JP2008107499A - Polarizing plate and liquid crystal display device - Google Patents

Abstract

The present invention provides a polarizing plate that is small in dimensional change due to heat and humidity and has high durability, and a liquid crystal display device in which unevenness due to light leakage is suppressed.
A polarizer, a protective film A installed on one surface of the polarizer, and a protective film B installed on the other surface of the polarizer, the protective film A being 60 The moisture permeability at 95 ° C. and 95% RH is 50 g / m ² · day to 300 g / m ² · day, and the moisture permeability of the protective film B at 60 ° C. and 95% RH is 300 g / m ² · day or less. It is a polarizing plate etc. characterized by this.
[Selection figure] None

Description

  The present invention relates to a polarizing plate and a liquid crystal display device.

  Recently, liquid crystal display devices (hereinafter referred to as LCDs) are widely used in place of CRTs because of their thinness, light weight, and low power consumption. The demand for polarizing plates is rapidly increasing with the spread of LCDs. The field of use is also expanding from small products such as conventional calculators and watches to large products such as automotive instruments, PC monitors, and televisions.

In the polarizing plate, a protective film (hereinafter sometimes referred to as a protective layer) is bonded to both sides or one side of a polarizer having polarizing ability through an adhesive layer. As a material of the polarizer, polyvinyl alcohol (hereinafter sometimes referred to as PVA) is mainly used. After the PVA film is uniaxially stretched, it is dyed with iodine or a dichroic dye or dyed. A polarizer is formed by stretching and further crosslinking with a boron compound.
The protective film is mainly cellulose triacetate (hereinafter referred to as TAC) because it is optically transparent and has low birefringence, a smooth surface, and excellent adhesion to a polarizer made of PVA by saponification. Is sometimes used).

As the demand for larger size and display quality of liquid crystal display devices in recent years increases, liquid crystal display devices such as VA mode, IPS mode, OCB mode, etc. have spread as the display mode, compared to the conventional TN mode, Techniques using various retardation films as viewing angle compensation films have been proposed for the purpose of widening the viewing angle for each mode.
These retardation films are desired to be used as a protective film for a polarizer for the purpose of further reducing productivity and cutting costs by cutting the production process.
As a retardation film, it is known that an optically anisotropic layer is laminated on a cellulose acylate film or is prepared by performing a stretching process, but as other useful retardation films, a norbornene resin, Retardation films such as polycarbonate resin have been proposed, and these are used for polarizing plates and liquid crystal display devices because of their low dimensional change rate, low photoelastic coefficient, high hydrophobicity and low moisture permeability, etc. The film is expected as a film capable of improving the durability in the case of the above, and a technique for further improving the adhesion to the polarizer is required for the film mainly composed of these highly hydrophobic resins.

  On the other hand, since the display device is always in use for a long time, the polarizing plate has long-term durability so that the image quality of the LCD is not deteriorated even in long-term use in an environment having temperature and humidity changes. Sex has come to be required. In addition, with the expansion of applications, durability under severe conditions such as higher temperature and higher humidity has been required.

  Furthermore, with the widespread use of display devices, the required display quality has become higher, and when using cellulose triacetate as a protective film, unevenness of the display image due to light leakage during long-term use occurs. Has been pointed out as a problem, and there is a strong demand for improvement against such problems. It is estimated that the cause of these unevenness is that any of the members used is distorted due to deformation of the protective film or cell due to the contraction of the polarizer due to the entry and exit of moisture over time, and a phase difference occurs. Therefore, there is a demand for countermeasures by suppressing the entry and exit of moisture in the polarizing plate.

  As a technology to solve these various problems, by reducing the moisture permeability and moisture content of the protective film on the side opposite to the cell and the side of the polarizing plate (surface side) and improving the water resistance of the protective film, It is expected to improve the durability of the polarizing plate and suppress the occurrence of unevenness due to light leakage.

As a protective film with improved water resistance, for example, it has been reported that a sheet made of a norbornene resin is useful as a highly hydrophobic resin (see Patent Document 1).
However, a sheet made of a norbornene-based resin has a problem that moisture permeability is sufficiently small and it is difficult to receive a change in humidity, but adhesion to a polarizer is insufficient and productivity is low.
Although the technique which improves adhesiveness is proposed with respect to these problems (refer patent documents 2-3), it is still not a sufficient level in the situation where durability in higher temperature and high humidity conditions is calculated | required.

As another means, a technique of a protective film using a sheet made of polyester resin such as polyethylene terephthalate or other hydrophobic resin such as polycarbonate resin and further improving adhesiveness has been proposed (patent) References 4-8).
However, even if these techniques are used, the adhesiveness is not at a sufficient level even for a high demand for durability under severe conditions of higher temperature and higher humidity.

In addition, as a result of further diligent investigations on a protective film having high water resistance for the purpose of improving the durability of the polarizing plate, the present inventors have mainly used these highly hydrophobic resins such as norbornene resin, polyester resin and polycarbonate resin. When the sheet is used as a protective film for a polarizer, it can be seen that in a higher temperature durability test such as 100 ° C., the polarization performance deteriorates, which causes a problem. It was necessary to establish a technique to improve durability.
Furthermore, when using a retardation film made of a hydrophobic resin such as norbornene resin or polycarbonate resin as a protective film on the cell side, and directly sticking it to a polarizer, as a protective film on the opposite surface side When a protective film made of norbornene resin, polyester resin, or polycarbonate resin with high water resistance is used, productivity increases due to the heavy load of drying and annealing compared to the conventional bonding methods, even with the previously proposed bonding methods. In the durability test of polarizing plates at higher temperatures and higher humidity, there was a problem that the polarization performance deteriorated and peeling due to insufficient adhesion between the polarizer and the protective film occurred. .

JP-A-10-101907 Japanese Patent Laid-Open No. 2001-174637 JP 2001-305345 A JP 2004-219620 A JP 2002-90546 A JP-A-8-271733 JP-A-8-240716 JP-A-2005-275216

The present invention aims to solve the above-described problems and achieve the following objects. That is, an object of the present invention is to provide a highly durable polarizing plate that is small in dimensional change due to heat and humidity.
Another object of the present invention is to provide a liquid crystal display device in which unevenness due to light leakage is suppressed.

The present invention is based on the above findings by the present inventors, and means for solving the above problems are as follows. That is,
<1> It has a polarizer, a protective film A installed on one surface of the polarizer, and a protective film B installed on the other surface of the polarizer, and the protective film A is 60 ° C. The moisture permeability at 95% RH is 50 g / m ² · day to 300 g / m ² · day, and the moisture permeability at 60 ° C. and 95% RH of the protective film B is 300 g / m ² · day or less. It is a polarizing plate characterized by these.
<2> The polarizing plate according to <1>, wherein the sum of moisture permeability at 60 ° C. and 95% RH of the protective film A and the protective film B is 100 g / m ² · day or more.
<3> The dimensional change rate of the protective film B before and after being left for 100 hours at 60 ° C. and 90% RH is 0.3% or less for at least one of the TD direction and the MD direction of the protective film B < The polarizing plate according to any one of <1> to <2>.
<4> The dimensional change rate of the protective film B before and after being left for 100 hours at 90 ° C. and 2.7% RH is 0.02% or less for at least one of the TD direction and the MD direction of the protective film B. The polarizing plate according to any one of <1> to <3>.
<5> The polarizing plate according to any one of <1> to <4>, wherein the protective film B has a photoelastic coefficient of 10 × 10 ⁻¹³ cm ² / dyne or less.
<6> The polarizing plate according to any one of <1> to <5>, wherein the protective film B is made of at least one of a thermoplastic saturated norbornene resin, a polycarbonate resin, and a polyester resin.
<7> The polarizing plate according to any one of <1> to <6>, wherein the protective film A has an equilibrium water content at 25 ° C. and 80% RH of 1.5% or more.
<8> The polarizing plate according to <7>, wherein the protective film A includes a base material layer containing cellulose acylate and a coating layer having low moisture permeability.
<9> The polarizing plate according to <8>, wherein a hard coat layer is formed on the coating layer of the protective film A.
<10> The polarizing plate according to any one of <1> to <9>, wherein the surface of the protective film B to be bonded to the polarizer is subjected to a hydrophilic treatment.
<11> The polarizing plate according to any one of <1> to <10>, having an adhesive layer or a pressure-sensitive adhesive layer between the protective film B and the polarizer.
<12> The polarizing plate according to any one of <1> to <11>, wherein the polarizer is produced by stretching a film containing at least polyvinyl alcohol.

  <13> A liquid crystal cell and a polarizing plate installed in the liquid crystal cell, wherein the polarizing plate is the polarizing plate according to any one of <1> to <12>, and a protective film B It is a liquid crystal display device which is installed so as to face a liquid crystal cell.

According to the present invention, it is possible to provide a highly durable polarizing plate with small dimensional change due to heat and humidity.
In addition, according to the present invention, it is possible to provide a liquid crystal display device in which unevenness due to light leakage is suppressed.

Below, the polarizing plate and liquid crystal display device which concern on this invention are demonstrated in detail.
In the description of the present embodiment, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
In the description of the present embodiment, “45 °”, “parallel” or “orthogonal” means that the angle is within a range of strictly less than ± 5 °. The error from the exact angle is preferably less than 4 °, more preferably less than 3 °. Regarding the angle, “+” means the clockwise direction, and “−” means the counterclockwise direction. Further, the “slow axis” means a direction in which the refractive index is maximized. The “visible light region” means 380 to 780 nm. Further, the refractive index measurement wavelength is a value in the visible light region (λ = 550 nm) unless otherwise specified.

In the description of the present embodiment, the term “polarizing plate” is used to include both a long polarizing plate and a polarizing plate cut into a size incorporated in a liquid crystal device unless otherwise specified. Yes. The “cutting” here includes “punching” and “cutting out”.
In the description of the present embodiment, “polarizing film” and “polarizing plate” are distinguished from each other. However, “polarizing plate” is a laminate having a transparent protective film that protects the polarizing film on at least one side of “polarizing film”. It shall mean the body.

  In this specification, Re (λ) and Rth (λ) represent in-plane retardation and retardation in the thickness direction at the wavelength λ, respectively. Re (λ) is measured with KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments Co., Ltd.) by making light having a wavelength of λ nm incident in the normal direction of the film.

(Polarizer)
Although the structure in one Embodiment of the polarizing plate of this invention is shown to FIG. 1A and FIG. 1B, the polarizing plate of this invention is not restricted to this structure.
As shown in FIG. 1A and FIG. 1B, the polarizing plate of the present invention comprises a polarizer and protective films (protective films) A and B installed on one surface and the other surface of the polarizer, respectively. The protective film A includes at least a base material layer 1 and a layer 2 having low moisture permeability.
In these layers, as shown in FIG. 1A, the layer 2 having low moisture permeability may be on the polarizer side, and as shown in FIG. 1B, the base material layer 1 may be on the polarizer side. From the viewpoint of productivity and durability, the form shown in FIG. 1A is more preferable. It is preferable to further laminate a hard coat layer above the protective film A.
The hard coat layer preferably further comprises two or more layers having different refractive indexes. In this case, the refractive index of the surface-side layer is preferably low.
Moreover, it is also preferable to give internal scattering property and surface scattering property by including a particle.
The protective film B may be composed of only the base material layer 3 or the optically anisotropic layer 4 may be further laminated on the base material layer 3.
Furthermore, it is preferable to provide an easy-adhesion layer between the base material layer 3 and the polarizer for the purpose of improving adhesiveness. The easy adhesion layer may be a single layer, but is preferably composed of a plurality of layers. It is also preferable to use any one of the easy-adhesion layers as an antistatic layer.

<Polarizer>
The polarizer of the present invention is preferably composed of polyvinyl alcohol (PVA) and a dichroic molecule. However, as described in JP-A-11-248937, PVA and polyvinyl chloride are dehydrated and dechlorinated. A polyvinylene polarizer in which a polyene structure is generated and oriented is thereby used.

  PVA is a polymer material obtained by saponifying polyvinyl acetate, but may contain components copolymerizable with vinyl acetate such as unsaturated carboxylic acid, unsaturated sulfonic acid, olefins, and vinyl ethers. Further, modified PVA containing an acetoacetyl group, a sulfonic acid group, a carboxyl group, an oxyalkylene group, or the like may be used.

There is no restriction | limiting in particular as a saponification degree of PVA, According to the objective, it can select suitably, For example, 80-100 mol% is preferable from viewpoints of solubility etc., and 90-100 mol% is more preferable.
Moreover, there is no restriction | limiting in particular as a polymerization degree of PVA, According to the objective, it can select suitably, For example, 1,000-10,000 are preferable and 1,500-5,000 are more preferable.
The syndiotacticity of PVA is not particularly limited and can be appropriately selected according to the purpose. For example, as described in Japanese Patent No. 2978219, 55% or more is required to improve durability. However, as described in Japanese Patent No. 3317494, 45 to 52.5% can be preferably used. After PVA is formed into a film, it is preferable to introduce a dichroic molecule to constitute a polarizer.
As a method for producing a PVA film, a method of forming a film by casting a stock solution obtained by dissolving a PVA resin in water or an organic solvent is generally preferably used. The concentration of the polyvinyl alcohol-based resin in the stock solution is usually 5 to 20% by mass, and a PVA film having a thickness of 10 to 200 μm can be produced by forming this stock solution by casting.
The PVA film can be produced with reference to the production methods described in Japanese Patent No. 3342516, Japanese Patent Application Laid-Open No. 09-328593, Japanese Patent Application Laid-Open No. 2001-302817, and Japanese Patent Application Laid-Open No. 2002-144401.

There is no restriction | limiting in particular as a crystallinity degree of a PVA film, According to the objective, it can select suitably, For example, the average crystallinity degree (Xc) described in patent 3251073 gazette of 50-75 mass% In order to reduce in-plane hue variation, a PVA film having a crystallinity of 38% or less described in JP-A-2002-236214 may be used.
The birefringence (Δn) of the PVA film is preferably small, and a PVA film having a birefringence of 1.0 × 10 ⁻³ or less described in Japanese Patent No. 3342516 can be preferably used. However, as described in JP-A-2002-228835, in order to obtain a high degree of polarization while avoiding cutting during stretching of the PVA film, the birefringence of the PVA film may be set to 0.02 or more and 0.01 or less. Alternatively, as described in JP-A-2002-060505, the value of (nx + ny) / 2-nz may be set to 0.0003 or more and 0.01 or less.
The in-plane retardation Re of the PVA film is preferably 0 nm or more and 100 nm or less, and more preferably 0 nm or more and 50 nm or less.
The retardation Rth in the (film) thickness direction of the PVA film is preferably 0 nm or more and 500 nm or less, and more preferably 0 nm or more and 300 nm or less.
In addition, as a polarizing plate of the present invention, a PVA film having a 1,2-glycol bond amount of 1.5 mol% or less described in Japanese Patent No. 3021494, and Japanese Patent Application Laid-Open No. 2001-316492. A PVA film having 500 or less optical foreign matters of 5 μm or more per 100 cm ² , and a PVA film having a hot water cutting temperature spot of 1.5 ° C. or less in the TD direction of the film described in JP-A-2002-030163 Further, PVA formed from a solution in which 15 to 10% by mass of a plasticizer described in JP-A 06-289225 is mixed with 1 to 100 parts by mass of a trivalent or hexavalent polyhydric alcohol such as glycerin. A film is preferably used.

The film thickness before stretching of the PVA film is not particularly limited and can be appropriately selected depending on the purpose. For example, from the viewpoint of film holding stability and stretching uniformity, 1 μm to 1 mm is preferable. 20-200 micrometers is more preferable. Further, as described in JP-A-2002-236212, a thin PVA film may be used in which the stress generated when stretching 4 to 6 times in water is 10 N or less.
Dichroic molecule I ₃ ^- or I ₅ ^- higher iodine ion such as, or a dichroic dye is preferably used. Among them, higher-order iodine ions are particularly preferably used in the present invention. Higher-order iodine ions were obtained by dissolving iodine in an aqueous potassium iodide solution as described in “Application of Polarizing Plate” by Nagata Ryo, CMC Publishing and Industrial Materials, Vol. 28, No. 7, p39-p45. PVA can be immersed in a liquid and / or boric acid aqueous solution, and can be produced in a state of being adsorbed and oriented in PVA.
When a dichroic dye is used as the dichroic molecule, an azo dye is preferable, and among them, a bisazo dye and a trisazo dye are more preferable. The dichroic dye is preferably a water-soluble dye. For this reason, a hydrophilic substituent such as a sulfonic acid group, an amino group or a hydroxyl group is introduced into the dichroic molecule, so that a free acid, an alkali metal salt, an ammonium salt or an amine is introduced. It is preferably used as a salt.

Specific examples of such dichroic dyes include C.I. I. DirectRed37, CongoRed (C.I.DirectRed28), C.I. I. DirectViolet 12, C.I. I. DirectBlue90, C.I. I. DirectBlue 22, C.I. I. DirectBlue1, C.I. I. DirectBlue 151, C.I. I. Benzidines such as DirectGreen 1, C.I. I. Direct Yellow 44, C.I. I. DirectRed 23, C.I. I. Diphenylurea series such as DirectRed 79, C.I. I. Stilbene series such as Direct Yellow 12, C.I. I. Dinaphthylamine type such as DirectRed 31, C.I. I. DirectRed 81, C.I. I. DirectViolet 9, C.I. I. Examples include J acid systems such as DirectBlue 78.
In addition, C.I. I. Direct Yellow 8, C.I. I. Direct Yellow 28, C.I. I. Direct Yellow 86, C.I. I. Direct Yellow 87, C.I. I. Direct Yellow 142, C.I. I. Direct Orange 26, C.I. I. Direct Orange 39, C.I. I. Direct Orange 72, C.I. I. Direct Orange 106, C.I. I. Direct Orange 107, C.I. I. DirectRed2, C.I. I. DirectRed 39, C.I. I. DirectRed 83, C.I. I. DirectRed 89, C.I. I. DirectRed 240, C.I. I. DirectRed 242, C.I. I. DirectRed 247, C.I. I. DirectViolet 48, C.I. I. DirectViolet 51, C.I. I. DirectViolet 98, C.I. I. DirectBlue 15, C.I. I. DirectBlue 67, C.I. I. DirectBlue 71, C.I. I. DirectBlue 98, C.I. I. DirectBlue 168, C.I. I. DirectBlue 202, C.I. I. DirectBlue 236, C.I. I. DirectBlue 249, C.I. I. DirectBlue 270, C.I. I. DirectGreen 59, C.I. I. DirectGreen 85, C.I. I. Direct Brown 44, C.I. I. Direct Brown 106, C.I. I. Direct Brown 195, C.I. I. Direct Brown 210, C.I. I. Direct Brown 223, C.I. I. Direct Brown 224, C.I. I. DirectBlack1, C.I. I. DirectBlack17, C.I. I. DirectBlack 19, C.I. I. Direct Black 54 and the like are further disclosed in JP-A-62-70802, JP-A-1-161202, JP-A-1-172906, JP-A-1-172907, JP-A-1-183602, JP-A-1-183602. The dichroic dyes described in Japanese Patent No. 248105, Japanese Patent Application Laid-Open No. 1-265205, and Japanese Patent Application Laid-Open No. 7-261024 are preferably used. In order to produce dichroic molecules having various hues, two or more of these dichroic dyes may be blended. When a dichroic dye is used, the adsorption thickness may be 4 μm or more as described in JP-A-2002-082222.

If the content of the dichroic molecule in the film is too small, the degree of polarization is low, and if it is too large, the single-plate transmittance is lowered. Therefore, the polyvinyl alcohol polymer constituting the film matrix is usually used. On the other hand, it is adjusted to a range of 0.01% by mass to 5% by mass.
As a preferable film thickness of the polarizer, 5 to 40 μm is preferable, and 10 to 30 μm is more preferable. Further, as described in JP-A-2002-174727, the ratio between the thickness of the polarizer and the thickness of the protective film described later is 0.01 ≦ A (polarizer film thickness) / B (protective film thickness). ) ≦ 0.8 is also preferable.

<Protective film A>
The protective film A constituting the polarizing plate of the present invention is a protective film that is bonded to a surface opposite to the liquid crystal cell when bonded to a liquid crystal cell with respect to a polarizer made of polyvinyl alcohol.
The protective film A is a film characterized in that the moisture permeability at 60 ° C. and 95% RH is 50 g / m ² · day to 300 g / m ² · day, and further, at 25 ° C. and 80% RH. The film is characterized in that the equilibrium moisture content is 1.5% or more.
Further, the protective film A may consist of only the base material layer, and may include at least the base material layer and the coating layer, but has a low moisture permeability and a moisture content of 1.5% or more. In order to achieve both, it is preferable that the substrate layer and the coating layer are formed.
The moisture permeability at 60 ° C. and 95% RH is more preferably 60 g / m ² · day to 250 g / m ² · day, and more preferably 70 g / m ² · day to 200 g / m ² · day. Is more preferable.
Further, the equilibrium water content at 25 ° C. and 80% RH is more preferably 1.8% or more, and further preferably 2.0% or more.

<< Base material layer >>
As a base material layer of the protective film A, moisture permeability and equilibrium water content only have to be within a desired range, and the composition thereof includes cellulose resin, polyester resin, polycarbonate resin, saturated alicyclic structure-containing polymer resin, A resin such as an acrylic resin, a melamine resin, or a polyethylene resin can be used, and it is preferably made of a cellulose resin or a saturated alicyclic structure-containing polymer resin, and more preferably a cellulose acylate film made of a cellulose resin. preferable.

[Cellulose acylate film]
The substrate layer of the transparent substrate film A of the present invention is a cellulose acylate film because it is optically uniform, has a smooth surface, and has good secondary workability in producing a polarizing plate. Is preferably used.
The cellulose acylate used in the present invention is an aliphatic carboxylic acid ester or aromatic carboxylic acid ester having about 2 to 22 carbon atoms, and is particularly preferably a lower fatty acid ester of cellulose.
The lower fatty acid in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms. For example, cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate phthalate, etc. Mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate as described in JP-A-8-231761, U.S. Pat. No. 2,319,052 are used. Alternatively, esters of aromatic carboxylic acids and cellulose described in JP-A Nos. 2002-179701, 2002-265639, and 2002-265638 are also preferably used.
Among the above description, the lower fatty acid esters of cellulose that are particularly preferably used are cellulose triacetate and cellulose acetate propionate described later. These cellulose esters can also be mixed and used.

The degree of substitution (DS) of cellulose acylate means the ratio of acylation of three hydroxyl groups present in the cellulose structural unit (glucose having β1 → 4 glycosidic bonds).
The degree of substitution can be calculated by measuring the amount of bound fatty acid per unit mass of cellulose. The measurement method is carried out according to ASTM-D817-91.
The cellulose acylate of the present invention balances the humidity dependence of the retardation and the dimensional stability by appropriately balancing the hydrophobicity of the acyl group and the hydrophilicity of the hydroxyl group.
That is, if the alkyl chain in the acyl group is too short on average and / or the hydroxyl group ratio is too high, the humidity dependency of retardation increases.
On the other hand, if the alkyl chain in the acyl group is too long on average and / or the hydroxyl group ratio is too high, Tg is lowered and the dimensional stability is deteriorated.
Accordingly, the cellulose triacetate preferably used in the present invention preferably has a degree of acetylation of 2.83 or more and 2.91 or less and no other acyl group having 3 or more carbon atoms, and the degree of acetylation is 2.84 or more and 2. 89 or less is more preferable.

  In addition, cellulose ester other than cellulose triacetate has an acyl group having 2 to 4 carbon atoms as a substituent, the substitution degree of acetyl group is X, and the substitution degree of propionyl group is Y, the following formula ( It is a cellulose ester that satisfies both a) and (b).

2.6 ≦ X + Y ≦ 2.9 Equation (a)
0 ≦ X ≦ 2.5 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Formula (b)

  Here, among cellulose esters satisfying the above formulas (a) and (b) at the same time, cellulose acetate propionate (total acyl group substitution) of 1.9 ≦ X ≦ 2.5 and 0.1 ≦ Y ≦ 0.9 Degree = X + Y) is preferred. The portion not substituted with an acyl group usually exists as a hydroxyl group. These can be synthesized by known methods.

  30-120 micrometers is preferable and, as for the thickness of a transparent base film, 40-80 micrometers is more preferable. If the thickness of the base film is equal to or greater than the lower limit, problems such as a decrease in film strength are unlikely to occur. If the thickness is equal to or less than the upper limit, the mass increases excessively, particularly for large televisions of 20 inches or more. It is preferable because adverse effects such as disadvantages are less likely to occur.

-UV absorber-
It is preferable that two or more kinds of ultraviolet absorbers represented by the following general formula (1) are contained in any of the transparent substrate film, moisture-proof layer, undercoat layer, and hard coat layer of the present invention.
In the following general formula (1), R ¹ , R ² , R ³ , R ⁴ and R ⁵ each independently represent a hydrogen atom or a monovalent organic group, and at least one of R ¹ , R ² and R ³ Represents an unsubstituted branched or straight chain alkyl group having 4 to 20 carbon atoms in total, and R ¹ , R ² and R ³ are different from each other.
In addition, the average value (hereinafter referred to as average log P) of octanol / water partition coefficient (hereinafter referred to as log P) represented by the following mathematical formula (c) relating to the ultraviolet absorber and the acylation degree DS of cellulose acylate are represented by the following mathematical formula (d It is more preferable that a cellulose acylate film satisfying the relationship (2) is used as the transparent substrate film.
Here, in the following mathematical formula (c), W _n represents the mass fraction of the nth ultraviolet absorber, and (logP) _n represents “logP” of the nth ultraviolet absorber.

5.0 × DS−6.7 ≦ average log P ≦ 5.0 × DS−5.1... (D)

The average value of logP of the ultraviolet absorbent used in the present invention is (5.0 × DS−6.7) or more and (5.0 × DS−5.1) or less, and (5.0 × DS− 6.5) or more and (5.0 × DS-5.2) or less is preferable.
If the average value of log P is too large, the surface shape is deteriorated, and if the average value of log P is too small, the retentivity of the ultraviolet absorbent under high temperature and high humidity is deteriorated.
Moreover, the compound represented by General formula (1) has an absorption maximum in the wavelength range of 330-360 nm.

The UV absorber used in the present invention preferably has a molecular weight of 250 to 1,000 from the viewpoint of volatility, more preferably 260 to 800, still more preferably 270 to 800, and 300 to 800. It is particularly preferred that
A specific monomer structure may be used as long as these molecular weights are within the range, and an oligomer structure or a polymer structure in which a plurality of the monomer units are bonded may be used.
Moreover, it is preferable that a ultraviolet absorber does not volatilize in the process of dope casting of cellulose acylate film preparation, and drying.

--Compound addition amount--
The addition amount of the above-mentioned ultraviolet absorber is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, and 0.2 to 3% by mass with respect to cellulose acylate. % Is more preferable.

--Method of compound addition--
Further, the timing of adding these ultraviolet absorbers may be any time during the dope preparation process, or may be performed at the end of the dope preparation process.

Next, the ultraviolet absorber represented by the general formula (1) will be described in detail.
R ¹ , R ² , R ³ , R ^4, and R ⁵ each independently represent a hydrogen atom or a monovalent organic group, and at least one of R ¹ , R ^2, and R ³ is a non-carbon having 4 to 20 carbon atoms. It represents a substituted branched or straight chain alkyl group, and R ¹ , R ² and R ³ are different from each other.
Examples of the substituent include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methyl, ethyl, iso-propyl, tert-butyl, and n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2 to 8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), an alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2-8, for example, propargyl, 3-pentynyl, etc.), aryl groups (preferably having 6-30 carbon atoms) More preferably, it has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyl, p-methylphenyl, naphthyl and the like, and a substituted or unsubstituted amino group (preferably having 0 to 0 carbon atoms). 20, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, and examples thereof include amino, methylamino, dimethylamino, diethylamino, dibenzylamino and the like.

An alkoxy group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methoxy, ethoxy, butoxy, etc.), an aryloxy group (preferably C6-C20, More preferably C6-C16, Most preferably C6-C12, for example, phenyloxy, 2-naphthyloxy, etc.), acyl groups (preferably C1-C1) 20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as acetyl, benzoyl, formyl, pivaloyl, etc.), an alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, and more). Preferably it has 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonyl or ethoxycarbonyl. An aryloxycarbonyl group (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, such as phenyloxycarbonyl). An acyloxy group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as acetoxy and benzoyloxy), an acylamino group (preferably having a carbon number) 2 to 20, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as acetylamino, benzoylamino, etc.), an alkoxycarbonylamino group (preferably having 2 to 20 carbon atoms, More preferably, it has 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms. An aryloxycarbonylamino group (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino). ), A sulfonylamino group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include methanesulfonylamino and benzenesulfonylamino). A sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms, such as sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl, etc. ), A carbamoyl group (preferably having 1 to 20 carbon atoms, More preferably, it is C1-C16, Most preferably, it is C1-C12, for example, carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl etc. are mentioned. ), An alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio, ethylthio, etc.), an arylthio group (preferably carbon 6 to 20, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio, and the like, and a sulfonyl group (preferably 1 to 20 carbon atoms, more preferably carbon atoms). 1 to 16, particularly preferably 1 to 12 carbon atoms such as mesyl, tosyl, etc.), sulfinyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably carbon atoms). 1 to 12, for example, methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably having 1 to 1 carbon atoms) 0, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as ureido, methylureido, phenylureido, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms, More preferably, it has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include diethyl phosphoric acid amide and phenyl phosphoric acid amide), hydroxy group, mercapto group, halogen atom (for example, fluorine atom, Chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 and the hetero atom includes, for example, a nitrogen atom, an oxygen atom, a sulfur atom, specifically, for example, an imidazoli , Pyridyl, quinolyl, furyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc.), a silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably Are those having 3 to 24 carbon atoms, and examples thereof include trimethylsilyl and triphenylsilyl). These substituents may be further substituted.
Further, when there are two or more substituents, they may be the same or different, and may be connected to each other to form a ring if possible, but at least one of R ¹ , R ² and R ³ is It represents an unsubstituted branched or straight chain alkyl group having a total carbon number of 4 to 20, and R ¹ , R ² , and R ³ are different from each other.

R ¹ and R ³ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, and a halogen atom, more preferably A hydrogen atom, an alkyl group, an aryl group, an alkyloxy group, an aryloxy group and a halogen atom, more preferably a hydrogen atom and a C1-12 alkyl group, particularly preferably a C1-12 alkyl group (preferably Is carbon number 4-12).

R ² is preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, or a halogen atom, more preferably a hydrogen atom, An alkyl group, an aryl group, an alkyloxy group, an aryloxy group, and a halogen atom, more preferably a hydrogen atom and an alkyl group having 1 to 12 carbon atoms, particularly preferably a hydrogen atom and a methyl group, most preferably a hydrogen atom. It is.

R ⁴ and R ⁵ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, and a halogen atom, more preferably A hydrogen atom, an alkyl group, an aryl group, an alkyloxy group, an aryloxy group, and a halogen atom, more preferably a hydrogen atom and a halogen atom, and particularly preferably a hydrogen atom and a chlorine atom.

  Although the specific example of a compound represented by General formula (1) below is given, this invention is not limited to the following specific example at all.

-Plasticizer-
Examples of the plasticizer that can be used for the transparent substrate film of the present invention include polyhydric alcohol ester plasticizers, glycolate plasticizers, phosphate ester plasticizers, and phthalate ester plasticizers. Particularly preferred are polyhydric alcohol plasticizers and glycolate plasticizers.
Moreover, it is preferable to set it as 16 mass% or less with respect to a film, as for the addition amount of a phosphate ester plasticizer, it is more preferable to set it as 10 mass% or less, and it is still more preferable to set it as 6 mass% or less.

  The polyhydric alcohol ester is composed of an ester of a dihydric or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule.

The polyhydric alcohol used in the present invention is represented by the following general formula (2).
However, in the following general formula (2), R ₁ represents an n-valent organic group, n represents a positive integer of 2 or more, and an OH group represents an alcoholic and / or phenolic hydroxyl group.

Examples of the polyhydric alcohol represented by the general formula (2) include the following, but the present invention is not limited to these.
Specifically, adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol 1,3-butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, galactitol, mannitol, Examples include 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, and xylitol.
Among these, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, and xylitol are particularly preferable.

  There is no restriction | limiting in particular as monocarboxylic acid used for the polyhydric alcohol ester of this invention, Well-known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid, etc. are used. Use of an alicyclic monocarboxylic acid or aromatic monocarboxylic acid is preferred in terms of improving moisture permeability and retention.

  Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.

  As the aliphatic monocarboxylic acid, a fatty acid having a straight chain or side chain having 1 to 32 carbon atoms is preferably used. The number of carbon atoms is more preferably 1-20, and particularly preferably 1-10. When acetic acid is contained, the compatibility with the cellulose ester is increased, and it is also preferable to use a mixture of acetic acid and another monocarboxylic acid.

  Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid, tridecylic acid , Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, laccelic acid, undecylenic acid, And unsaturated fatty acids such as oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid.

  Examples of preferred alicyclic monocarboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, or derivatives thereof.

  Examples of preferred aromatic monocarboxylic acids include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and two or more benzene rings such as biphenylcarboxylic acid, naphthalenecarboxylic acid, and tetralincarboxylic acid. The aromatic monocarboxylic acid which has, or those derivatives are mentioned. Benzoic acid is particularly preferable.

  The molecular weight of the polyhydric alcohol ester is not particularly limited, but is preferably 300 to 1,500, and more preferably 350 to 750. A higher molecular weight is preferred because it is less likely to volatilize, and a smaller one is preferred in terms of moisture permeability and compatibility with cellulose ester.

  The carboxylic acid used for the polyhydric alcohol ester may be one kind or a mixture of two or more kinds. Moreover, all the OH groups in the polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are.

  The specific compound of a polyhydric alcohol ester is shown below.

The glycolate plasticizer is not particularly limited, but a glycolate plasticizer having an aromatic ring or a cycloalkyl ring in the molecule is preferably used.
As a preferable glycolate type plasticizer, for example, butylphthalylbutyl glycolate, ethylphthalylethyl glycolate, methylphthalylethyl glycolate or the like is used.

  For phosphate plasticizers, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenylbiphenyl phosphate, trioctyl phosphate, tributyl phosphate, etc. For phthalate ester plasticizers, phthalate ester In diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, butyl benzyl phthalate, dibenzyl phthalate, butyl phthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, methyl phthalyl Examples of citrate plasticizers such as ethyl glycolate include triethyl citrate, tri-n-butyl citrate, acetate Le triethyl citrate, acetyl tri-n-butyl citrate, acetyl tri-n-(2-ethylhexyl) citrate and the like are used.

  These plasticizers can be used alone or in combination of two or more. 4-20 mass% is preferable with respect to a cellulose ester, and, as for the usage-amount of a plasticizer, 6-16 mass% is more preferable, and 8-13 mass% is still more preferable. If the added amount of the plasticizer is too large, the film becomes too soft and the water absorption modulus decreases. If the added amount is too small, the moisture permeability of the film decreases.

  In addition to the plasticizers described above, various additives are used in the transparent base film of the present invention for the purpose of controlling film properties such as durability, moisture permeability, and elastic modulus of the substrate, and optical property values. For example, JP 2006-30937 A [0054] to [0134], JP 2003-12859 A, JP 2002-20410 A, JP 2003-222723 A [0031] to [0044]. ], The compounds described in JP-A-2002-22756, [0045] to [0058] can be used.

<< Coating layer >>
As the coating layer of the protective film A, the moisture permeability is reduced so that the moisture permeability at 60 ° C. and 95% RH when laminated on the base material layer is 50 g / m ² · day to 300 g / m ² · day. Any effect may be used, such as polyvinylidene chloride resin, polyvinyl alcohol, ethylene polyvinyl alcohol copolymer, resin component in which inorganic layered compound is dispersed, silica-based resin layer, and other hydrophobic compounds. The case where it is used will be described in detail.
The value of moisture permeability used in the present invention is measured from the base material side when measuring a protective film having a coating layer in which an inorganic layered compound is dispersed in a polyvinyl alcohol, an ethylene vinyl alcohol copolymer, and a resin layer thereof. The value of moisture permeability is used.
In general, in the case of a resin having a high density of hydrogen bonding groups such as vinyl alcohol resin, when the resin layer is directly exposed to high humidity, the hydrogen bond between the molecular chains is hindered by moisture and the water vapor barrier property is reduced. The value of moisture permeability from the resin layer side is often not included in the range described in the present invention because it significantly decreases, but the value of moisture permeability from the base film side is 50 g / m ² · day or more and 300 g or more. If it satisfies the range of not more than / m ² · day, the effect of improving the wet heat resistance of the polarizing plate is sufficiently exhibited.

[Coating layer made of polyvinylidene chloride resin]
The coating layer of the present invention is also preferably made of a polyvinylidene chloride resin (hereinafter also referred to as a chlorine-containing polymer) containing a repeating unit derived from a chlorine-containing vinyl monomer.
In general, examples of the chlorine-containing vinyl monomer include vinyl chloride and vinylidene chloride. A chlorine-containing polymer can be obtained by copolymerizing these vinyl chloride or vinylidene chloride monomers with a monomer copolymerizable therewith.

-Monomers copolymerizable with chlorine-containing vinyl monomers-
Examples of the copolymerizable monomer include olefins, styrenes, acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, itaconic acid diesters, maleic acid esters, fumaric acid diesters, N- Examples thereof include monomers selected from alkylmaleimides, maleic anhydride, acrylonitrile, vinyl ethers, vinyl esters, vinyl ketones, vinyl heterocyclic compounds, glycidyl esters, unsaturated nitriles, unsaturated carboxylic acids and the like.

  Examples of olefins include dicyclopentadiene, ethylene, propylene, 1-butene, 1-pentene, isoprene, chloroprene, butadiene, 2,3-dimethylbutadiene and the like.

  Examples of styrenes include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, chloromethyl styrene, methoxy styrene, acetoxy styrene, chloro styrene, dichloro styrene, bromo styrene, trifluoromethyl styrene, vinyl. And benzoic acid methyl ester.

Specific examples of acrylic esters and methacrylic esters include the following.
Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, t-octyl acrylate, 2-methoxyethyl acrylate, 2-butoxyethyl acrylate, 2-phenoxyethyl acrylate, chloroethyl acrylate, Cyanoethyl acrylate, dimethylaminoethyl acrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, oct Methacrylate, benzyl methacrylate, cyanoacetoxyethyl methacrylate, chlorobenzyl methacrylate, sulfopropyl methacrylate, N-ethyl-N-phenylaminoethyl methacrylate, 2-methoxyethyl methacrylate, 2- (3-phenylpropyloxy) ethyl methacrylate, dimethylamino Phenoxyethyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, phenyl methacrylate, cresyl methacrylate, naphthyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, 3 -Chloro-2-hydro Cypropyl methacrylate, 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, diethylene glycol monoacrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, 2,2-dimethyl-3-hydroxypropyl methacrylate, 5-hydroxypropyl Methacrylate, diethylene glycol monomethacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate.

Specific examples of vinyl ethers include the following.
Methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethyl hexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl ether, dimethylaminoethyl Vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, vinyl phenyl ether, vinyl tolyl ether, vinyl chlorophenyl ether, vinyl-2,4-dichlorophenyl ether, vinyl naphthyl ether, vinyl anthranyl ether .

Specific examples of the vinyl esters include the following.
Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl dimethyl propionate, vinyl ethyl butyrate, vinyl valerate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, Vinyl butoxy acetoacetate, vinyl phenyl acetate, vinyl acetoacetate, vinyl lactate, vinyl-β-phenylbutyrate, vinyl cyclohexyl carboxylate, vinyl benzoate, vinyl salicylate, vinyl chlorobenzoate, vinyl tetrachlorobenzoate, vinyl naphthoate.

  Acrylamides include acrylamide, methylacrylamide, ethylacrylamide, propylacrylamide, butylacrylamide, t-butylacrylamide, cyclohexylacrylamide, benzylacrylamide, hydroxymethylacrylamide, methoxyethylacrylamide, dimethylaminoethylacrylamide, phenylacrylamide, dimethylacrylamide, and diethyl. Examples include acrylamide, β-cyanoethyl acrylamide, and N- (2-acetoacetoxyethyl) acrylamide.

  Examples of methacrylamides include methacrylamide, methyl methacrylamide, ethyl methacrylamide, propyl methacrylamide, butyl methacrylamide, tert-butyl methacrylamide, cyclohexyl methacrylamide, benzyl methacrylamide, hydroxymethyl methacrylamide, methoxyethyl methacrylamide , Dimethylaminoethylmethacrylamide, phenylmethacrylamide, dimethylmethacrylamide, diethylmethacrylamide, β-cyanoethylmethacrylamide, N- (2-acetoacetoxyethyl) methacrylamide and the like.

  Further, acrylamides having a hydroxyl group can also be used, and examples thereof include N-hydroxymethyl-N- (1,1-dimethyl-3-oxo-butyl) acrylamide, N-methylolacrylamide, and N-methylol. Examples include methacrylamide, N-ethyl-N-methylol acrylamide, N, N-dimethylol acrylamide, N-ethanol acrylamide, N-propanol acrylamide, N-methylol acrylamide, and the like.

Examples of itaconic acid diesters include dimethyl itaconate, diethyl itaconate, and dibutyl itaconate. Examples of maleic acid diesters include diethyl maleate, dimethyl maleate, and dibutyl maleate.
Examples of the fumaric acid diesters include diethyl fumarate, dimethyl fumarate, dibutyl fumarate, and the like.

Examples of vinyl ketones include methyl vinyl ketone, phenyl vinyl ketone, methoxyethyl vinyl ketone, and the like.
Examples of the vinyl heterocyclic compound include vinyl pyridine, N-vinyl imidazole, N-vinyl oxazolidone, N-vinyl triazole, and N-vinyl pyrrolidone.
Examples of glycidyl esters include glycidyl acrylate and glycidyl methacrylate.
Examples of unsaturated nitriles include acrylonitrile and methacrylonitrile.
Examples of N-alkylmaleimides include N-ethylmaleimide and N-butylmaleimide.

  Examples of the unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid and the like, and further anhydrides such as fumaric acid, itaconic acid and maleic acid. Two or more kinds of these copolymerizable monomers may be used.

  Examples of the chlorine-containing polymer in the present invention include JP-A-53-58553, JP-A-55-43185, JP-A-57-139109, JP-A-57-139136, JP-A-60. -235818, JP-A 61-108650, JP-A 62-256871, JP-A 62-280207, JP-A 63-256665, and the like.

  The proportion of the chlorine-containing vinyl monomer in the chlorine-containing polymer is preferably from 50 to 99 mass%, more preferably from 60 to 98 mass%, still more preferably from 70 to 97 mass%. If the ratio of the chlorine-containing vinyl monomer is 50% or more, problems such as deterioration in moisture permeability do not occur, and if it is 99% or less, solubility in various solvents is obtained, which is preferable.

Chlorine-containing polymers are available from Asahi Kasei Chemicals Corporation and Kureha Chemical Corporation. The following are listed as available from Asahi Kasei Chemicals Corporation.
“Saran Resin R241C”, “Saran Resin F216”, “Saran Resin R204”, “Saran Latex L502”, “Saran Latex L529B”, “Saran Latex L536B”, “Saran Latex L544D”, “Saran Latex L549B”, “Saran Latex L551B” “Saran Latex L557”, “Saran Latex L561A”, “Saran Latex L116A”, “Saran Latex L411A”, “Saran Latex L120”, “Saran Latex L123D”, “Saran Latex L106C”, “Saran Latex L131A”, “ “Saran Latex L111”, “Saran Latex L232A”, “Saran Latex L321B”.

The thickness of the coating layer is preferably 1 to 10 μm, more preferably 2 to 9 μm, and still more preferably 3 to 8 μm. If the thickness is 1 μm or less, the moisture-proof property is inferior. Conversely, if the thickness is 10 μm or more, the film is not suitable as a protective film because it becomes a brittle film or is easily colored.
Further, the haze of the coating layer is preferably 5% or less, more preferably 3% or less, and still more preferably 1% or less. The ratio between the surface haze and the internal haze may be arbitrary, but the surface haze is more preferably 1% or less.

Since the coating layer of the present invention is often wet coated, the solvent used in the coating composition is an important factor. Requirements include sufficiently dissolving the above solute and being less likely to cause coating unevenness and drying unevenness during the coating to drying process.
Also, the solubility of the transparent base film is not too high (necessary for preventing failure such as deterioration of flatness and whitening), and conversely, the support (base layer) is dissolved and swollen to the minimum extent ( Necessary for adhesion) is also a preferable characteristic. One type of solvent may be used, but it is particularly preferable to adjust the solubility of the support, the swelling property, the solubility of the material, the drying property, the aggregation property of the particles, and the like by using two or more types of solvents.
By adding a small amount of highly swellable solvent to the low-swelling main solvent of the transparent support, it is possible to improve the adhesion with the transparent support without deteriorating other performance and surface condition. it can.
The coating solution may contain an organic solvent such as a ketone, alcohol, ester or ether. Preferred organic solvents are tetrahydrofuran, ketones (methyl ethyl ketone, acetone, methyl isobutyl ketone, cyclohexanone, etc.), ethyl acetate, and butyl acetate. BTXs such as toluene are also preferably used.
In the present invention, when the chlorine-containing polymer is vinylidene chloride, it is preferable to use tetrahydrofuran as the main solvent. Further, it is more preferable to use a copolymer of vinylidene chloride so that it can be dissolved in toluene, a ketone solvent, etc., and toluene, a ketone solvent, etc. are used without using tetrahydrofuran. Further, it is also preferable to add the above solvent within a range where the solute dissolves in tetrahydrofuran.
When the chlorine-containing polymer is supplied as a latex dispersion, water is preferably used as the main solvent. In the case of a latex dispersion, it is preferable to use a surfactant, a thickener or the like in combination.

When coating a coating layer containing a chlorine-containing polymer on a transparent substrate film, Silicia (made by Fuji Silysia), Mizuka Seal (made by Mizusawa Chemical Co., Ltd.), NipSeal (made by Nippon Silica Industry Co., Ltd.) is used to improve blocking resistance. 0.2 to 1.0 part of silica powder such as) or the like, paraffin wax (manufactured by Nippon Seiwa), behenic acid (manufactured by NOF), stearic acid (manufactured by NOF) It is also preferable to add 0.2 to 5.0 parts of a wax emulsion such as Also, modified waxes are preferably used as described in paragraphs [0012] to [0016] of JP-A-9-143419.
Since the chlorine-containing polymer is decomposed and colored by heat, light, and ultraviolet rays, it is preferable that stearic acid such as lead, zinc, barium, silver salts, magnesium oxide, or the like is used together as a stabilizer. Moreover, you may use antioxidants as described in Paragraph [0013]-[0020] of Unexamined-Japanese-Patent No. 2004-359819.
Furthermore, in order to increase the adhesion between the coating layer containing the chlorine-containing polymer and the transparent substrate film, and other layers, isocyanates such as Coronate L (made by Nippon Polyurethane) and Takenate A-3 (Takeda Pharmaceutical). It is also preferable to add 0.1 to 1.0 part of an adhesive with respect to the chlorine-containing polymer.

  As the coating layer of the present invention, in addition to the coating layer composed of the chlorine-containing resin layer, it is also preferable to use a coating layer composed of the resin layer described in (1) to (5) below.

(1) Coating layer formed from a resin comprising a vinyl alcohol polymer or a resin containing an inorganic layered compound in a vinyl alcohol polymer composition (1-1) Vinyl alcohol polymer Constructing a coating layer Examples of the vinyl alcohol polymer to be used include homopolymers such as polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH), and the like. In addition, these vinyl alcohol polymers may be partially carbonyl-modified, silanol-modified, epoxy-modified, acetoacetyl-modified, amino-modified or ammonium-modified, and a part thereof is a diacetone acrylamide unit. You may use the copolymer containing etc. Moreover, various vinyl alcohol polymers can be used alone or in combination of two or more.

  The saponification degree of the vinyl alcohol polymer can be selected from a range of 80 mol% or more, but is preferably 96 mol% or more, and more preferably 99 mol% or more. The degree of polymerization of the vinyl alcohol polymer is preferably 200 to 5,000, more preferably 400 to 5,000, and still more preferably about 500 to 3,000, from the viewpoint of moisture permeability and coatability.

(1-2) Other components In the present invention, as a component of the resin composition, a vinyl alcohol polymer cross-linking agent can be further added to the vinyl alcohol polymer and the layered inorganic compound described later. The water resistance of the adhesive layer can be improved.
The crosslinking agent that can be used for this purpose is not particularly limited, and any known crosslinking agent can be preferably used.
Examples of crosslinking agents include phenolic resin, melamine resin, urea resin, polyamide polyurea, dimethylol urea, dimethylol melamine, polyvalent epoxy compound, dialdehyde compound, polyvalent isocyanate resin, aziridine compound, polyamidoamine epichlorohydrin compound, activity Vinyl compound, dicarbonate compound, hydrazino group-containing compound (other-valent carboxylic acid polyhydrazide compound), colloidal silica, zirconium salt, polyvalent metal salt, boric acid, phosphoric acid, polyacrylic acid, dicarboxylic acid, adipic anhydride And titanium compounds such as succinic anhydride, tetraisopropyl titanate, diisopropoxybis (acetylacetone) titanate, and other coupling agents such as 3-glycidpropylmethoxysilane, The use of such a radical generating agent such as id are possible. It is also possible to add a catalyst and other additives for promoting the crosslinking reaction.

The addition amount of the crosslinking agent is preferably 0.5% by mass or more, more preferably 1% by mass or more, and particularly preferably 2% by mass or more in terms of (crosslinking agent / (vinyl alcohol polymer + crosslinking agent)). .
In the case where the mass ratio of the crosslinking agent to both the PVA polymer and the crosslinking agent is less than 0.5% by mass, the effect is not exhibited by adding the crosslinking agent.
The mass ratio of the crosslinking agent to both the vinyl alcohol polymer and the crosslinking agent is preferably 50% by mass or less, more preferably 40% by mass or less, and particularly preferably 30% by mass or less. Since some crosslinking agents such as aldehyde-based compounds turn yellow by heat, it is necessary to reduce the amount of such crosslinking agents to be within an allowable range by reducing the amount of addition.

(1-3) Formation of coating layer The coating layer which consists of a vinyl alcohol-type polymer or a vinyl alcohol-type polymer and an inorganic layered compound can be formed on a transparent material film using the below-mentioned coating system. At this time, in order to optimize the viscosity characteristic of the liquid for the coating apparatus during film formation, a method of adjusting the liquid viscosity of the coating liquid by adding a viscosity modifier such as a thickener to the coating liquid is also used. You can also.
In order to further improve the moisture resistance and water resistance of the coating layer, it is preferable to heat-treat the resin layer at 90 ° C. or higher and 150 ° C. or lower for several minutes after applying the coating layer on the cellulose acylate substrate. It is more preferable to heat at a temperature of from 150 ° C. to 150 ° C. The heat treatment time is preferably from 1 minute to 20 minutes, more preferably from 5 minutes to 15 minutes, from the viewpoint of productivity and water resistance. Moreover, it is preferable that the cellulose acylate is previously saponified from the viewpoint of adhesion between the resin layer and the cellulose acylate substrate.

(1-4) Thickness, haze, and surface roughness of coating layer The thickness of the coating layer is preferably in the range of 1 to 30 μm, and more preferably about 3 to 20 μm.
The haze value of the produced resin layer is preferably 30% or less, more preferably 10% or less, and still more preferably 8% or less.
The internal haze value is preferably 10% or less, more preferably 5% or less, and still more preferably 1% or less.
The arithmetic average roughness Ra of the surface is preferably 0.2 or less, the square root roughness Rq is preferably 0.2 or less, and the ten-point average roughness Rzjis is preferably 1.5 or less.

(1-5) Configuration As shown in FIGS. 2A to 2D which are polarizing plate configuration diagrams, the coating layer is between a polarizer and a transparent substrate film, or a polarizer is a transparent substrate film. It can be provided on the opposite side across the surface.
Moreover, although it can also provide in these both sides, this resin layer was provided between the polarizer and the transparent base film from the viewpoint of productivity at the time of polarizing plate processing, applicability of the hard coat layer, and the like. The case is more preferably used. However, even when the polarizer is provided with the resin layer on the opposite side across the transparent base film, the productivity at the time of polarizing plate processing is not reduced, and the following is described on the resin layer: By providing an easy-adhesion layer, it is possible to further provide a layer having a hard coat property or the like thereon.

(2) Coating layer formed from silica-based coating film The silica-based coating film used in the present invention is provided on at least one surface of a transparent substrate film made of cellulose acylates, achieves the desired moisture permeability, and In order to withstand practical use as a protective film, it is necessary to achieve both compactness and flexibility.
Accordingly, only a silica film, which is a hydrolyzate produced by adding a catalyst and water to an alkoxysilane and hydrolyzing and condensing, is insufficient in flexibility and not suitable for the present invention. In the present invention, it is composed of alkoxysilane. A coating film containing a compound, a compound having a functional group that reacts with a hydroxyl group or an alkoxyl group, and / or a silane coupling agent is preferably used, and a compound composed of alkoxysilane and a functional group that reacts with a hydroxyl group or an alkoxyl group. It is particularly preferable that all of the compound and the silane coupling agent are contained.

(2-1) Compound Composed of Alkoxysilane The compound composed of alkoxysilane used in the present invention is represented, for example, by the following general formula (1). In the following general formula (3), R ₁ represents a hydrogen atom, an alkyl group or an acyl group, R ₂ represents a hydrogen atom, an alkyl group or an aromatic group, and n represents a number of 2 to 4.

In the general formula (3), examples of the alkyl group represented by R ₁ include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the acyl group include an acetyl group and a propionyl group. Among these, a methyl group, an ethyl group, and a propyl group are particularly preferable, and an ethyl group is most preferable. n is preferably 2 to 4, more preferably 3 to 4, and still more preferably 4.
Accordingly, tetraalkoxysilane is preferable, tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane are particularly preferable, and tetraethoxysilane is particularly preferable. When n is 2 or 3, examples of the alkyl group represented by R ₂ include an alkyl group having 1 to 18 carbon atoms, preferably 1 to 5 carbon atoms, and examples of the aromatic group include a phenyl group. It is done.

(2-2) Compound having a functional group that reacts with a hydroxyl group or an alkoxyl group In the present invention, a compound having a functional group that reacts with a hydroxyl group or an alkoxy group is used.
Monomers, oligomers, and polymers having a functional group that reacts with a hydroxyl group or an alkoxyl group are more preferably used, and those having a functional group that reacts with a hydroxyl group or an alkoxyl group can be used without particular limitation.
For example, a monomer or oligomer having a hydroxyl group in which a thermosetting, ionizing curable, or moisture curable resin selected from an acrylic resin, a polyester resin, an epoxy resin, a urethane resin, and a melamine resin is used. , Polymers are more preferable, polymers having a hydroxyl group are particularly preferable, vinyl alcohol polymers such as polyvinyl alcohol (PVA) homopolymers and ethylene-vinyl alcohol copolymers (EVOH) are more preferably used. A homopolymer of alcohol (PVA) is particularly preferably used.
In addition, it is possible to use a part of these vinyl alcohol polymers modified with a carbonyl group or the like, a copolymer containing a diacetone acrylamide unit or the like in part. Moreover, various vinyl alcohol polymers can be used alone or in combination of two or more.

  As a vinyl alcohol polymer preferably used as a compound having a functional group that reacts with a hydroxyl group or an alkoxyl group, the saponification degree of the vinyl alcohol polymer can be selected from a range of 80 mol% or more, but 96 mol% or more is selected. Preferably, 98 mol% or more is more preferable. The degree of polymerization of the vinyl alcohol polymer is preferably 200 to 5,000, more preferably 400 to 5,000, and still more preferably about 500 to 3,000, from the viewpoint of moisture permeability and coatability.

(2-3) Silane coupling agent In this invention, a silane coupling agent is used. The silane coupling agent is not particularly limited as long as it is a compound having an alkoxysilane at the terminal, but at the same time, vinyl group, epoxy group, acrylic group or methacryl group, amine group, mercapto group, hydroxyl group, isocyanate group, carboxyl group, acid Those having an anhydride group are more preferred, and those having an epoxy group, an amine group, an acrylic group or a methacryl group are even more preferred.

  As the silane coupling agent having a vinyl group, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane and the like are preferably used.

  Examples of the silane coupling agent having an epoxy group include β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, and γ-glycidoxypropyltrimethoxysilane. Γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane and the like are preferably used.

  Examples of silane coupling agents having an acrylic group or a methacryl group include γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, and γ-methacryloxypropyltriethoxysilane. Etc. are preferably used.

  Examples of the silane coupling agent having an amine group include N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ- Aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane and the like are preferably used.

  As the silane coupling agent having a mercapto group, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane and the like are preferably used.

  As the silane coupling agent having an isocyanate group, γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane and the like are preferably used.

  In the present invention, the silane coupling agent may be used simultaneously with a compound having a functional group that reacts with a hydroxyl group or an alkoxyl group. It is preferable to use a silane coupling agent having a group.

  In the present invention, since the silane coupling agent is used simultaneously with the compound comprising alkoxysilane, from the viewpoint of increasing the reaction rate of dehydration polycondensation of alkoxysilane, a silane coupling agent having an amine group is used. preferable.

  In the present invention, a layer having a hard coat property is preferably provided on the coating layer, and in order to improve interlayer adhesion with the layer having a hard coat property, a silane coupling agent having an acryl group or a methacryl group. It is particularly preferable to use

Another preferred embodiment of the silane coupling agent that can be used in the present invention is a silane coupling agent having alkoxysilanes at both ends.
The silane coupling agent having alkoxysilane at both ends is desirable in that it can be crosslinked with a compound comprising alkoxysilane. Examples of the compound include organic chain-containing both-end functional silane monomers described in JP-A-2000-326448. Etc. are preferably used.

  In the present invention, a hydrolyzate of a silane coupling agent and a partial condensate of the hydrolyzate of a silane coupling agent are also preferably used. In the present invention, the silane coupling agent includes a hydrolyzate of the silane coupling agent and a partial condensate of the hydrolyzate of the silane coupling agent.

  Silane coupling agents having an epoxy group, an amine group, an acrylic group, or a methacryl group may be used alone, but it is more preferable to use two or more types in combination, and it is particularly preferable to use three types in combination. A tertiary amine soluble in an organic solvent is used as a polycondensation catalyst for increasing the reaction rate, and two types of silane coupling agent having an epoxy group and an acryl group or methacryl group are simultaneously used. Is more preferable.

When the contents of the compound comprising an alkoxysilane, the compound having a functional group that reacts with a hydroxyl group or an alkoxyl group, and the silane coupling agent are a mass%, b mass%, and c mass%, respectively (in this case, from alkoxysilane) The content of the compound is calculated from the calculated value after the polycondensation in the case of ideal condensation), when two types of compounds comprising an alkoxysilane and a compound having a functional group that reacts with a hydroxyl group or an alkoxyl group are used. A / b is preferably 10/90 to 90/10, more preferably 20/80 to 80/20, and particularly preferably 40/60 to 80/20. In the case of using two types of compounds comprising an alkoxysilane and a silane coupling agent, a / b is preferably 40/60 to 95/5, and more preferably 50/50 to 90/10.
In the case of simultaneously using a compound comprising an alkoxysilane, a compound having a functional group that reacts with a hydroxyl group or an alkoxyl group, and a silane coupling agent, a / (b + c) is preferably 10/90 to 90/10, 20 / 80-80 / 20 is more preferable, and 40 / 60-80 / 20 is particularly preferable. In that case, b / c is preferably 10/90 to 90/10, more preferably 20/80 to 80/20, and still more preferably 40/60 to 80/20.

(2-4) Other components In the present invention, a catalyst and water are used to advance the polycondensation reaction of the compound comprising alkoxysilane as described above.
Examples of curing catalysts include hydrochloric acid, nitric acid, acetic acid, oxalic acid, maleic acid, fumaric acid and other acids, and N, N-dimethylbenzylamine, tripropylamine, tributylamine, and tripentylamine which are soluble in organic solvents. An amine, an organic metal, a metal alkoxide, or the like is used.
1-10 mass% is preferable with respect to 100 mass parts of compounds which consist of alkoxysilanes, and, as for the addition amount, 1-5 mass parts is still more preferable.
Moreover, about water addition, the quantity more than the quantity which a partial hydrolyzate can hydrolyze 100% theoretically is preferable, and the quantity equivalent to 110-300% is more preferable. More preferably, an amount equivalent to 120 to 200% is added.
Furthermore, in this invention, a ultraviolet absorber can also be contained in a coating layer as needed.
Moreover, when using the silane coupling agent which has an acryl group or a methacryl group, it contains about 0.5-5 mass% of photoinitiators of the term of the hard-coat layer mentioned later of silane coupling agent content. Is also preferable.

(2-5) Coating solvent As the solvent of the coating composition for forming the silica-based coating film as the coating layer of the present invention, water, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol, It is preferable to use one or a mixture of two or more octanols. The amount of the solvent is preferably adjusted so that the solid concentration is 15 to 60% by mass.

(2-6) Polysilazane Another preferable material of the silica-based coating film as the coating layer of the present invention is a cured product of a coating composition containing polysilazane. Polysilazane described in paragraph Nos. 0097 to 0104 described in 240103 is preferable. Although it is possible to use polysilazane alone, it is also possible to use it in place of the above-mentioned compound comprising alkoxysilane.

(2-7) Adhesiveness with a base material When using a silica-type coating film as a coating film of this invention, adhesiveness with a transparent base film becomes a subject. In order to improve the adhesion, it is also preferable to form a silica-based coating film on the transparent base film after providing an undercoat layer described later, but the productivity decreases due to the increase in the number of layers. Since problems such as an increase in cost and an increase in layer thickness occur, in the present invention, it is more preferable to perform a pretreatment such as a hydrophilic treatment or an uneven treatment on one or both sides of the base film.
Examples of the pretreatment include corona discharge treatment, glow discharge treatment, chromic acid treatment (wet), saponification treatment (wet), flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment, etc., but corona discharge treatment, glow discharge treatment. Saponification treatment (wet) is particularly preferred, and saponification treatment is more preferred.

(2-8) Adhesion with Hard Coat Layer When a silica-based coating film is used as the coating film of the present invention, the adhesion with the hard coat layer is another problem. One of the effective means for improving the adhesion with the hard coat is that the silica-based coating film and / or the hard coat layer preferably contains a silane coupling agent. It is more preferable to include a coupling agent, and it is further preferable to include a silane coupling agent having the same functional group in both the silica-based coating film and the hard coat layer.
Since a polyfunctional acrylate or methacrylate monomer, oligomer, or polymer is generally used for the resin component of the hard coat layer, the silane coupling agent is more preferably a silane coupling agent having an acryl group or a methacryl group.

Another preferred means for improving the adhesion to the hard coat layer when a silica-based coating film is used as the coating film of the present invention is to provide an intermediate layer between the coating layer and the hard coat layer.
As the adhesion layer, an undercoat layer described later can be provided, but a layer containing a silane coupling agent is preferably provided, and a layer containing a silane coupling agent having an acryl group or a methacryl group is more preferably provided. It is more preferable to provide a layer containing a silane coupling agent and a polyfunctional polyfunctional acrylate or methacrylate monomer, oligomer or polymer at the same time.
When providing the layer containing a silane coupling agent, the hydrolyzate of a silane coupling agent and the partial condensate of the hydrolyzate of a silane coupling agent are especially preferable. The thickness of the intermediate layer is preferably 0.05 to 2 μm.

(2-9) Thickness of the coating layer The thickness of the coating layer in the case where a silica-based coating film is used as the coating film of the present invention is preferably 0.2 to 10 µm, and 0.3 to 5 µm. More preferred is a thickness of 0.4-2 μm. If the thickness is 0.2 μm or less, the moisture-proof property is inferior. Conversely, if the thickness is 10 μm or more, the film is not suitable as a protective film because it becomes a brittle film or the curl becomes strong. The haze of the coating layer is preferably 5% or less, more preferably 3% or less, and still more preferably 1% or less. The ratio between the surface haze and the internal haze may be arbitrary, but the surface haze is more preferably 1% or less.

(2-10) Configuration As shown in FIGS. 2A to 2D, which are polarizing plate configuration diagrams when a silica-based coating film is used as the coating film of the present invention, the polarizer and the transparent substrate film Between or between the polarizer and the polarizer can be provided on the opposite side across the transparent substrate film.
Moreover, although it can also provide in these both sides, as shown to FIG. 2A and FIG. 2B, the direction provided in the other side on both sides of a transparent base film with a polarizer is adhesiveness with a polarizer, and a polarizing plate. It is preferable in terms of processability.
A configuration having a hard coat layer on the surface as shown in FIG. 2B is particularly preferable from the viewpoint of scratch resistance and difficulty in cracking the coating layer.

(3) Coating layer made of a hydrophobic compound (3-1) Hydrophobic compound The coating layer having low moisture permeability of the present invention is constituted by constituting the main component of the matrix constituting the layer from a hydrophobic compound. Can be formed.
By forming a hydrophobic layer composed mainly of a hydrophobic compound, it is possible to suppress adsorption of water molecules to the membrane surface, dissolution into the membrane, and passage through the membrane, thereby reducing moisture permeability. can do.
Furthermore, by increasing the intermolecular interaction and other interactions between the compounds that form the matrix, or by carrying out more precise cross-linking, the degree of freedom of movement of the matrix molecules in the film is reduced, and the transparency is reduced. Wetness can be further reduced.
The binder system constituting the hydrophobic matrix that achieves these objectives includes a system composed of a hydrophobic monomer, a system composed of a hydrophobic monomer and a polyfunctional monomer (crosslinking agent), a system of a hydrophobic polymer, and a hydrophobic polymer. Examples thereof include a system composed of a crosslinking agent. Furthermore, examples of the binder having a large interaction between the compounds include a liquid crystal monomer system, a liquid crystal monomer / crosslinking agent system, a liquid crystalline polymer, a liquid crystal polymer / crosslinking agent system, and the like.
These binders preferably have a log P value of 1.0 or more and 12.0 or less, and preferably 2.0 or more and 11.5 or less from the viewpoint of handling properties such as hydrophobicity, solubility and film-forming properties. Is more preferably 3.0 or more and 11.0 or less.

(3-2) Log P value The octanol-water partition coefficient (log P value) can be measured by the flask immersion method described in JIS Japanese Industrial Standard Z7260-107 (2000).
Further, the octanol-water partition coefficient (log P value) can be estimated by a computational chemical method or an empirical method instead of the actual measurement.
As a calculation method, Crippen's fragmentation method (J. Chem. Inf. Comput. Sci., 27, 21 (1987)), Viswanadhan's fragmentation method (J. Chem. Inf. Comput. Sci., 29, 163). (1989)), Broto's fragmentation method (Eur. J. Med. Chem.-Chim. Theor., 19, 71 (1984)) and the like are preferably used, but the Crippen's fragmentation method (J. Chem. Inf .Comput.Sci., 27, 21 (1987)) is more preferable.
When the log P value of a certain compound varies depending on the measurement method or calculation method, it is preferable to determine whether or not the compound is within the scope of the present invention by the Crippen's fragmentation method.

Specifically as a hydrophobic monomer, a fluorine-type monomer, a cycloolefin type monomer, a monomer containing an aromatic, etc. can be used.
As the fluorine-based monomer, there can be used a fluorine-containing compound having a crosslinkable or polymerizable functional group described later, a compound described in JP-A-9-5519, a compound described in JP-A-2000-159840, and the like.
As the cycloolefin monomer, for example, compounds described in JP-A-2006-83225, JP-A-5-51542, JP-A-6-313056, and JP-A-6-340849 can be used.
Specific examples of the hydrophobic polymer include fluorine-based polymers, cycloolefin-based polymers, aromatic-containing polymers, and the like. A compound described in JP-A-7-70107, Reports Res. Lab. Asahi Glass Co. , Ltd., Ltd. , 55 (2005) P47-51 can be used.
Moreover, as a cycloolefin type polymer, the resin composition etc. which are described in Unexamined-Japanese-Patent No. 7-228673, Unexamined-Japanese-Patent No. 8-259784, etc. can be used.
In addition to the hydrophobic binder (monomer, polymer), the hydrophobic layer of the present invention is intended to improve the film density, reduce moisture permeability, and improve film properties such as brittleness and curl. , A polyfunctional polymerizable monomer or a crosslinkable monomer can be used in combination.
As monomers that can be used in combination, polyfunctional monomers and polyfunctional oligomers described in [Hard Coat Layer] described later can be used.

When the main component of the hydrophobic layer of the present invention is a monomer or a polymerizable compound, it can be cured and formed into a film by polymerization.
As the polymerization initiator used in this case, a photoinitiator described later can be used.
When using a polymerization initiator, it is preferable to use it in the range of 0.01-10.0 mass% with respect to a monomer or a polymeric compound as the usage-amount of a polymerization initiator, The range is more preferably 7.0% by mass, and still more preferably 0.5 to 5.0% by mass.

-Photoinitiator-
Examples of photoinitiators (photoradical polymerization initiators) include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides (Japanese Patent Laid-Open No. 2001-139663, etc.) ), 2,3-dialkyldione compounds, disulfide compounds, fluoroamine compounds, aromatic sulfoniums, lophine dimers, onium salts, borate salts, active esters, active halogens, inorganic complexes, coumarins, etc. Can be mentioned.

These initiators may be used alone or in combination.
“Latest UV Curing Technology”, Technical Information Association, 1991, p. 159, and “UV curing system” written by Kayo Kiyomi, 1989, General Technology Center, p. Various examples are also described in 65-148 and are useful in the present invention.

  Commercially available photo radical polymerization initiators include KAYACURE (DETX-S, BP-100, BDKM, CTX, BMS, 2-EAQ, ABQ, CPTX, EPD, ITX, QTX, BTC, manufactured by Nippon Kayaku Co., Ltd. MCA, etc.), Irgacure (651, 184, 500, 819, 907, 369, 1173, 1870, 2959, 4265, 4263, etc.) manufactured by Ciba Specialty Chemicals, Ltd., Esacure (KIP100F, KB1, manufactured by Sartomer) EB3, BP, X33, KT046, KT37, KIP150, TZT) and the like and combinations thereof are preferable examples.

  It is preferable to use a photoinitiator in the range of 0.1-15 mass parts with respect to 100 mass parts of polyfunctional monomers, and the range of 1-10 mass parts is more preferable.

  The above is a hydrophobic binder in organic solvent-based coating, but a water-dispersible polyester described in JP-A-2003-165188 can also be used as a material for aqueous coating.

(3-3) Thickness of hydrophobic layer and haze The thickness of the hydrophobic layer in the present invention is 0.5 μm from the viewpoint of the effect of reducing moisture permeability, film physical properties such as brittleness and curl, and productivity and cost. It is preferably 40 μm or less, more preferably 1.0 μm or more and 30 μm or less, and further preferably 2.0 μm or more and 25 μm or less.
The haze of the hydrophobic layer in the present invention is preferably low because it is handled as an optical film, preferably 5.0% or less, more preferably 3.0% or less, and 1.0% or less. More preferably. However, when it serves also as the hard-coat layer mentioned later or an anti-glare layer, it is preferable to become the range of the description mentioned later, respectively.

(3-4) Formation of mixed region The hydrophobic layer of the present invention comprises a hydrophilic cellulosic base film and a hydrophobic compound in order to reduce moisture permeability and maintain the strength and durability of the membrane. In order to ensure adhesion with the hydrophobic layer, it is preferable to form a mixed region in which both resins are mixed at the interface between the hydrophobic layer and the cellulose-based substrate film. By forming a mixed region, interference unevenness can be suppressed, and adhesion between a hydrophilic substrate film and a hydrophobic layer, which are usually poorly compatible, is ensured to reduce moisture permeability and improve film strength and durability. Can be maintained.
The thickness of the mixed region layer is preferably in the range of 0.2 to 10 μm, more preferably 0.3 to 7 μm, and still more preferably 0.5 to 5 μm. If the thickness of the layer in the mixed region is smaller than this range, the effect of suppressing interference unevenness and the effect on adhesion are small, and if larger than this range, the effect of reducing moisture permeability tends to be reduced.
The thickness of the layer in the mixed region was photographed by cutting the cross section of the antireflection film using a microtome, observing the cross section using a scanning electron microscope (S-570, manufactured by Hitachi, Ltd.) in the backscattered electron mode. The thickness of the layer in the mixed region can be obtained from the photograph.

In the present invention, it is necessary to select a solvent having a property of dissolving or swelling the support in order to form the mixed region as a solvent of the coating solution for forming the hydrophobic layer.
This is because if such a solvent is used in the coating solution, the interface between the base film and the hydrophobic layer becomes unclear, in order to form a hydrophobic layer while dissolving or swelling the support immediately after coating, A layer in a region where the resin component of the hydrophobic layer and the resin component of the base film are mixed is formed.

  Moreover, in order to maintain the function of reducing the moisture permeability of the hydrophobic layer, it is preferable to mix at least one solvent that does not dissolve the base film (for example, triacetyl cellulose support) and dissolve the base film. More preferably, at least one of the solvents has a higher boiling point than at least one of the solvents that do not dissolve the substrate film.

  Moreover, since the main component of the hydrophobic layer of this invention is a hydrophobic compound, it is thought that the solubility to the solvent which melt | dissolves or swells a base film is not enough. For this reason, it is preferable that at least one of the solvent that dissolves or swells the base film or the solvent that does not dissolve is a solvent having sufficient solubility for the hydrophobic compound of the present invention. In this case, a fluorine-based solvent can be preferably used particularly for a fluorine-based binder.

When the support is a cellulose acylate film, examples of the solvent having the property of dissolving or swelling the support include the following.
Ethers having 3 to 12 carbon atoms: Specifically, dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5- Trioxane, tetrahydrofuran, anisole, phenetole, etc.
Ketones having 3 to 12 carbon atoms: specifically, acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, methylcyclohexanone, etc.
Esters having 3 to 12 carbon atoms: Specifically, ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, propion brewed ethyl, n-pentyl acetate, γ-butyrolactone, etc. ,
Organic solvent having two or more kinds of functional groups: Specifically, methyl 2-methoxyacetate, methyl 2-ethoxyacetate, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropionate, 2-methoxyethanol, 2-propoxyethanol , 2-butoxyethanol, 1,2-diacetoxyacetone, acetylacetone, diacetone alcohol, methyl acetoacetate, and ethyl acetoacetate, etc. Chlorine-containing solvents: methylene chloride, chloroform,

  These can be used alone or in combination of two or more. As the solvent for dissolving the base film, a ketone solvent is preferable, and methyl ethyl ketone and cyclohexanone are particularly preferable.

As a solvent that does not dissolve the base film (preferably triacetyl cellulose), methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-methyl-2 -Butanol, cyclohexanol, isobutyl acetate, methyl isobutyl ketone, 2-octanone, 2-pentanone, 2-hexanone, 2-heptanone, 3-pentanone, 3-heptanone, 4-heptanone, toluene.
These can be used alone or in combination of two or more.

  Examples of other solvents that dissolve the fluorine-based binder include fluorine-containing solvents such as perfluoropentane, perfluoropropane, perfluorohexane, perfluoromethanol, and perfluoroethanol.

  The mass ratio (A / B) of the total amount (A) of the solvent that dissolves the base film and the total amount (B) of the solvent that does not dissolve the base film is preferably 10/90 to 100/0, and 20/80 to 100 / 0 is more preferable, and 30/70 to 100/0 is still more preferable.

(3-5) Adhesiveness with other layers The hydrophobic layer in the present invention is preferably further laminated with a hard coat layer, an antiglare layer and an antireflection layer, as used in the constitutional examples described later. It is more preferable to maintain adhesiveness with other layers. In this case, it can be formed directly on the hydrophobic layer, but as another method, by providing a layer similar to the [undercoat layer] described later, it is possible to achieve both adhesion and low moisture permeability.

(3-6) Configuration As shown in FIGS. 2A to 2D, which are polarizing plate configuration diagrams, the configuration of the low moisture permeable layer by the hydrophobic layer in the present invention is between the polarizer and the base film, or The polarizer can be provided on the opposite side of the substrate film.
Moreover, although it can also provide in these both sides, as shown in FIG. 2A and FIG. 2B, the direction provided on the opposite side across a base film with respect to the polarizer, adhesion to the polarizer, It is preferable in terms of processability.
Further, the hydrophobic layer in the present invention may also serve as a hard coat layer. In this case, the performance of the film may be equivalent to the performance of the hard coat layer described in another item.

(4) Coating layer using hydrophilic polyfunctional compound and crosslinking agent The low moisture permeability coating layer that can be used in the present invention is hydrophilic from the viewpoint of reducing moisture permeability by forming a dense film. A layer composed of a combination of a functional polyfunctional compound and a crosslinking agent is used.
Specifically, (A) a method using a layer formed by laminating a resin composition comprising a saccharide and a formyl group-containing compound, or (B) an amino group-containing polymer compound and an amino group-reactive functional group and silanol group A method using a layer formed by laminating a resin composition composed of an organic silane compound can be used. By using these crosslinkable compounds or reactive compounds in combination, the effect of densifying the film and the maintenance of low moisture permeability under high humidity conditions by reacting with hydrophilic functional groups can be achieved. it can.
In the present invention, a coating layer mainly composed of a compound containing these hydrophilic groups is formed as a low moisture-permeable layer on a cellulose-based transparent substrate having high hydrophilicity. Adhesiveness can be sufficiently ensured, moisture permeability can be further reduced, and a low moisture permeability layer excellent in durability of low moisture permeability can be formed.

(4-1) Composition of hydrophilic polyfunctional compound and crosslinking agent The resin composition comprising (A) a saccharide and a formyl group-containing compound in the present invention is described in JP-A-2003-23827 and JP-A-2003-238734. The resin composition described is used.
The resin composition described in JP-A-2004-255601 is used as the resin composition comprising the (B) amino group-containing polymer compound and the amino group-reactive functional group-containing silanol group-containing organic silane compound in the present invention. be able to.

(4-2) Surface treatment of substrate In the present invention, a coating layer is laminated for the purpose of sufficiently ensuring the adhesion between the coating layer using a hydrophilic polyfunctional compound and a crosslinking agent and the substrate. It is preferable to perform the surface treatment of the base film before.
As a general method for surface treatment of a substrate made of cellulose acylate, there is a purpose of improving adhesion with a polarizer made of PVA as a protective film for a polarizing plate, or PVA on a cellulose acylate film. For the purpose of producing an optical film in which an alignment layer such as a liquid crystal compound is formed on an alignment film, it is known to saponify the substrate surface. Adhesion is ensured by the hydrogen bond between the newly formed hydroxyl group and the hydroxyl group of PVA, and there is a concern that in the durability under high humidity conditions, the hydrogen bond is inhibited by moisture and the adhesion is lowered. .

On the other hand, in the present invention, a formyl group-containing compound contained in the resin composition (A) or an organic silane contained in the resin composition (B) by performing a surface treatment on the base film. Durability under high-humidity conditions is sufficiently ensured by the formation of a cross-link between the compound and the substrate film surface, and adhesion can be sufficiently ensured by further increasing the cross-linking.
As a surface treatment method, a known method such as a corona treatment, a flame treatment such as a plasma treatment, a saponification treatment, or the like can be selected. It is preferable to use the method described in 1 above, and it is particularly preferable to use the method of applying an alkaline solution.
As the surface contact angle of the substrate after the surface treatment, the water contact angle is preferably 50 degrees or less, more preferably 45 degrees or less, and further preferably 40 degrees or less.

Moreover, it is also preferable to use a coupling agent in the resin composition for the purpose of further improving the adhesion to the substrate.
As the coupling agent, for the resin composition of (A), a compound containing a plurality of hydroxyl-reactive functional groups, a compound containing a formyl-reactive functional group and a hydroxyl-reactive functional group, For the resin composition, a compound containing a silanol group and a hydroxyl group reactive functional group, a compound containing an amino group reactive group and a hydroxyl group reactive functional group, an amino group and a hydroxyl group reactive functional group And the like are used.
Here, examples of the functional group reactive with a hydroxyl group include an isocyanate group, an epoxy group, and a formyl group. Examples of the functional group reactive with a formyl group include a hydroxyl group, an amino group, and a thiol group. Examples of the functional group include an isocyanate group, an epoxy group, and a formyl group.

(4-3) Adhesiveness with other layers The coating layer using the hydrophilic polyfunctional compound of the present invention and a crosslinking agent is further functional layers such as a hard coat layer, an antiglare layer and an antireflection layer described later. Are preferably laminated. In this case, it is preferable to use a coupling agent in combination in the coating layer using a hydrophilic polyfunctional compound and a crosslinking agent from the viewpoint of ensuring adhesion with the functional layer.
As the coupling agent, a compound containing a formyl group and a polymerizable group, a silane coupling agent comprising a polymerizable group and an alkoxysilane, and the like are preferably used. Here, the polymerizable group is preferably a double bond group such as an acryloyl group, a methacryloyl group or an allyl group, and an epoxy group.
Examples of the silane coupling agent include the compounds described in the above-mentioned silane coupling agent, and a silane coupling agent having an epoxy group and a silane coupling agent having an acrylic group or a methacryl group are particularly preferable.
As a usage-amount of a silane coupling agent, it is preferable to use in the range of 0.01-10.0 mass% with the content in solid content in a coating composition, 0.1-7.0 mass% The range is more preferable, and the range of 0.5 to 5.0% by mass is still more preferable.

(4-4) Thickness of coating layer using hydrophilic polyfunctional compound and crosslinking agent, haze As thickness of coating layer using hydrophilic multifunctional compound and crosslinking agent of the present invention, moisture permeability is used. From the viewpoint of reducing effect, film properties such as brittleness and curl, and productivity and cost, it is preferably 0.5 μm or more and 40 μm or less, more preferably 1.0 μm or more and 30 μm or less, and 1.5 μm. More preferably, it is 25 μm or less.
Further, the haze of the coating layer using a hydrophilic polyfunctional compound and a crosslinking agent is preferably low because it is handled as an optical film, preferably 5.0% or less, and 3.0% or less. Is more preferable, and it is still more preferable that it is 1.0% or less.

(4-5) Configuration The configuration of the low moisture permeable layer by the coating layer using the hydrophilic polyfunctional compound and the crosslinking agent in the present invention is a polarizer as shown in FIGS. And the polarizer, or the polarizer can be provided on the opposite side of the substrate film. Moreover, although it can also provide in these both sides, as shown in FIG. 2A and FIG. 2B, the direction provided on the opposite side across a base film with respect to the polarizer, adhesion to the polarizer, It is preferable in terms of processability.

(5) Coating Layer Containing Inorganic Layered Compound In order to further reduce the moisture permeability of the coating layer of the present invention, it is more preferable to disperse the inorganic layered compound in a binder that can be used for the coating layer described above. . Since the inorganic stratiform compound has a hydrophilic surface, it is preferably dispersed and used in a water-soluble binder. In the coating layer made of the above-mentioned vinyl alcohol polymer or in the coating layer made of a silica-based coating film It is preferable to disperse, and it is more preferable to disperse in a coating layer made of a vinyl alcohol polymer. A particularly preferable performance can be exhibited by combining with the above-mentioned preferable vinyl alcohol polymer. On the other hand, when the inorganic layered compound is organically treated, it can be dispersed in a binder having low hydrophilicity, and moisture permeability can be lowered.

(5-1) Inorganic layered compound The inorganic layered compound in the present invention is an inorganic compound having a structure in which unit crystal layers are laminated, and having a property of swelling or cleaving by coordinating or absorbing a solvent between layers. is there.
Examples of such inorganic compounds include swellable hydrous silicates such as smectite group clay minerals (montmorillonite, saponite, hectorite, etc.), palm curite group clay minerals, kaolinite group clay minerals, phyllosilicates (mica). Etc.).
In addition, a synthetic inorganic layered compound is also preferably used. Examples of the synthetic inorganic layered compound include synthetic smectite (hectorite, saponite, stevensite, etc.), synthetic mica, etc., preferably smectite, montmorillonite, mica, montmorillonite, mica. Is more preferable, and mica is more preferable. Synthetic mica is particularly preferable from the viewpoint of moisture permeability reduction and suppression of coloring. Such inorganic layered compounds may be those obtained by subjecting these inorganic layered compounds to an organic treatment.

The swellable layered inorganic compound is preferably finely divided from the viewpoint of achieving both gas barrier properties and adhesion between the substrate and the gas barrier layer. The swellable layered inorganic compound that has been microparticulated is usually plate-shaped or flat-shaped, and the planar shape is not particularly limited, and may be an amorphous shape.
The average particle diameter (planar average particle diameter) of the swellable layered inorganic compound that has been microparticulated is preferably, for example, 0.1 to 10 μm, more preferably 0.5 to 8 μm, and even more preferably 0.8 to 6 μm. preferable. If the particle diameter is smaller than this range, the effect of reducing moisture permeability is not sufficient, and if the particle diameter is large, an increase in haze value, an increase in surface roughness, and the like are not preferable.
3-60 mass% is preferable, as for the density | concentration of an inorganic compound, 3-50 mass% is more preferable, and 3-40 mass% is still more preferable. If the concentration of the inorganic compound is less than 3% by mass, the effect of reducing moisture permeability is not sufficient, and if the concentration of the inorganic compound is more than 60% by mass, an increase in haze value and deterioration of brittleness are not preferable.

(5-2) Dispersion treatment of inorganic layered compound The inorganic layered compound is dispersed in the binder in a state where the interlayer is surely cleaved, thereby increasing the moisture transmission path length and decreasing the moisture permeability.
Therefore, a dispersion treatment for obtaining a state where each layer of the inorganic layered compound is appropriately cleaved is very important.
The dispersion treatment is preferably carried out by high-pressure dispersion treatment a plurality of times in the solution. At this time, the treatment pressure is preferably 10 MPa or more, and more preferably 20 MPa or more. The solvent is not particularly specified, but water or a water-soluble solvent (lower alcohol such as methanol, ethanol, isopropyl alcohol, acetone, etc.) can be exemplified for the inorganic layered compound not subjected to organic treatment, and water is particularly preferred. preferable. A mixed solvent of water and lower alcohol is also preferably used.
Examples of the high-pressure dispersion treatment method include a method in which a swellable layered inorganic compound is swollen in a solvent and then stirred by a high-pressure homogenizer to perform high-pressure dispersion.
The method for adjusting the coating solution is not particularly limited, but a method of dissolving the binder component of the coating layer described above uniformly in a solvent and then mixing it with a solvent in which layered particles are uniformly dispersed is effectively used.

(5-3) Organoorganically treated inorganic layered compound When the inorganic layered compound is dispersed in a compound having low hydrophilicity, it is preferable to use an inorganic layered compound that can be dispersed in an organic solvent. Compounds are more preferred.
Examples of these inorganic layered compounds are layered compounds subjected to an organic treatment with an organic agent such as alkylamine.
For the purpose of further strengthening the strength of the coating layer and reducing moisture permeability, it is preferable to perform an organic treatment with an organic agent containing a polymerizable group.
Organic layered inorganic layered compounds that can be used as commercial products include Somasif MAE / MTE / MEE / MPE (all synthetic mica manufactured by Coop Chemical Co., Ltd.), Lucentite SAN, STN, SEN, SPN (all corp chemical) Synthetic smectite manufactured by Co., Ltd.) or the like is used.

Further, organic layered inorganic layered compounds such as Lucentite ME-100 Corp. Chemical Co., Ltd. synthetic mica) and Lucentite SWN (Coop Chemical Corp. synthetic smectite) are organically treated. It is also preferable.
The organic agent is preferably a quaternary ammonium salt and is not particularly limited, but a quaternary ammonium salt represented by the following general formula (4) is more preferable.
In the following general formula (4), Ra is represented by (CH ₂ ) mH, (CH ₂ ) mRcH or (CH ₂ Rc) mH, m is an integer of 2 or more, and Rc is an arbitrary structure or Rb is CH ₃ , and n is 0 or an integer of 1 to 3. A ⁻ represents Cl ⁻ or Br ⁻ .

In the said General formula (4), 0-3 are preferable, 0-2 are preferable, and 0-1 are especially preferable. When n is large, dispersibility deteriorates, which is not preferable. With respect to Ra, all groups may have the same structure or different structures.
m is 2 or more, and in at least one group of Ra, m is particularly preferably 4 or more, more preferably 8 or more, and further preferably 8 to 30. The larger m is, the better the dispersibility, but it is not preferred, if it is too large, the ratio of organic matter to the inorganic layered compound becomes too large.

Ra also preferably has a structure in which interaction between molecules is large. Examples of the structure in which interaction between molecules is large include —OH, —CH ₂ CH ₂ O—, —CHO (CH) ₃ — and the like.
Examples of the quaternary ammonium salt used in the organic treatment include dimethyldioctadecylammonium bromide, trimethyloctadecylammonium chloride, benzyltrimethylammonium chloride, dimethylbenzyloctadecylammonium bromide, trioctylmethylammonium chloride, polyoxypropylenetrimethylammonium chloride, di ( Polyoxypropylene) dimethylammonium chloride, di (polyoxyethylene) dodecylmethylammonium chloride, tri (polyoxypropylene) methylammonium chloride, tri (polyoxypropylene) methylammonium bromide and the like.

In addition to the method of using the organically treated inorganic layered compound, the layered compound is sufficiently dispersed in an organic solvent, and a solution in which a hydrophobic binder is dissolved and / or dispersed in the solvent is added. For example, a method of adding the dispersed organically treated inorganic layered compound solution to the hydrophobic binder solution may be used.
In addition, as a method of directly adding the inorganic layered compound to the hydrophobic binder, a method of adding the inorganic layered compound in a molten state of the hydrophobic binder and dispersing it in the hydrophobic binder by a method such as kneading may be used. it can.

<< Configuration of Protective Film A >>
As for the protective film of this invention, the coating layer is formed on the transparent base film, and the suitable range differs in the thickness of a coating layer with the kind of coating layer as mentioned above. If the thickness of the coating layer is equal to or less than the upper limit value, it is preferable because it has excellent low moisture permeability and does not cause adverse effects such as increased curl. If the curl becomes too large, it will hinder subsequent processes for producing a polarizing plate, for example, a bonding process with a polarizing film and handling.
Further, it is not preferable that the curl remains not only in the manufacturing process but also as the polarizing plate, which causes display unevenness in the LCD.
Therefore, in order to reduce the curl to such an extent that no curling occurs or no problem in practical use, the upper limit of the thickness of the coating layer is preferably within the above range.
On the other hand, the lower limit of the film thickness is defined in a range that is more preferable than water permeability. The coating layer consists of at least one layer, and two or more layers are also possible. The use of two or more different coating layers at the same time among the coating layers of the present invention is particularly preferred from the viewpoint of reducing moisture permeability.

  The formed coating layer may be composed of a single layer or a plurality of layers, but is preferably a single layer that is simple in the production process. The single layer in this case refers to a coating layer formed of the same composition, and may be formed by a plurality of coatings as long as the composition after coating and drying has the same composition. On the other hand, the term “multiple layers” refers to the formation of a plurality of compositions having different compositions.

<< Moisture permeability of protective film A >>
Next, the moisture permeability will be described in detail. The measurement method of moisture permeability is "Polymer Physical Properties II" (Polymer Experiment Course 4, Kyoritsu Shuppan), pages 285-294: Measurement of vapor permeation (mass method, thermometer method, vapor pressure method, adsorption amount method) The film sample of 70 mmφ according to the present invention was conditioned at 60 ° C. and 95% RH for 24 hours, respectively, and from the mass difference before and after the humidity adjustment, according to JIS Z-0208, per unit area Was calculated (g / m ² ).
The moisture permeability of the commercially available cellulose acetate film measured by the above measurement method is generally 80 μm in thickness and the moisture permeability under the above conditions is 1,200 to 1,500 g / m ² · day.
From the viewpoint of suppressing light leakage due to deterioration of polarization performance and deformation such as contraction of the polarizer in the durability test, the upper limit of the moisture permeability of the protective film A of the present invention is 300 g / m ² · day or less. Preferably, it is 250 g / m ² · day or less, and more preferably 200 g / m ² · day or less.
If the moisture permeability is higher than the above upper limit, the polarizing plate is not sufficiently durable at high temperatures and high temperature and high humidity conditions when used as a protective film for polarizing plates, and polarized light due to changes in temperature and humidity during long-term use. The effect of reducing the occurrence of unevenness in the display image due to light leakage due to the change in the size of the film is low.
Moreover, from the viewpoint of polarizing plate durability at a high temperature such as 100 ° C. dry (2.7% RH), the moisture permeability of the protective film A should not be too low, and the lower limit of the moisture permeability is 50 g / m ² · day. The above is preferable, 60 g / m ² · day or more is more preferable, and 70 g / m ² · day or more is more preferable.
Further, from the viewpoint of productivity during polarizing plate processing, the sum of the protective film A and the protective film B is preferably 100 g / m ² · day or more, more preferably 150 g / m ² · day or more, and 180 g / m ² · day. The above is more preferable.
Therefore, the moisture permeability of the protective film A is particularly preferably in the range of 70 to 200 g / m ² · day. Within this range, the performance as a polarizing plate (polarization degree, single plate transmittance) does not deteriorate after the durability test, and due to the change in the size of the polarizing film due to changes in temperature and humidity during long-term use, It is possible to suppress the occurrence of unevenness in the display image, and it is possible to achieve both productivity in polarizing plate processing.

<< Moisture content of protective film A >>
The protective film A of the present invention is used as a protective film on the side opposite to the cell, and a protective film B described later is used as a protective film on the polarizing plate in combination with a protective film on the cell side. From the viewpoint of durability, for the purpose of increasing the hydrophilicity of the protective film and further improving the adhesion to the polarizing film, the equilibrium moisture content is preferably 1.5% or more, and 2.0% or more More preferably, it is 2.3% or more.

  In the present invention, fine particles may be added to the coating layer forming coating solution. By adding fine particles, effects such as improved hardness, improved adhesion to a transparent substrate film, and reduced moisture permeability can be obtained.

[Fine particles]
As the fine particles, any of inorganic fine particles, organic fine particles, and organic-inorganic composite fine particles can be used. Examples of the inorganic fine particles include silicon dioxide particles, titanium dioxide particles, zirconium oxide particles, aluminum oxide particles, antimony oxide particles, and indium oxide particles.

  In general, the inorganic fine particles may easily form aggregates or cracks in the coating layer after curing, simply by mixing. In the present invention, in order to increase the affinity between the inorganic fine particles and the organic component, the surface of the inorganic fine particles can be treated with a surface modifier containing an organic segment.

  2-40 volume% is preferable with respect to the volume of the coating layer after filling, as for the filling amount of microparticles | fine-particles, 3-30 volume% is more preferable, and 5-30 volume% is still more preferable.

  An inorganic layered compound can also be added to the coating layer forming coating solution as described above. As the layer compound, synthetic mica and synthetic smectite are preferably used.

<< Haze of Protective Film A >>
The haze of the protective film of the present invention is preferably 1.5% or less, more preferably 1.2% or less, and still more preferably 1.0% or less.
Moreover, it is preferable that the protective film of this invention is substantially colorless.
Here, “substantially colorless” means that the absolute values of a ^* and b ^* expressed in the L ^* , a ^* , b ^* color system are 3.0 or less, 2.5 The following is more preferable, and 2 or less is more preferable. Substantially colorless, it is preferable because the color tone is neutral gray when a polarizing plate is used, and troubles such as hindrance in color display do not occur.

As for the protective film in this invention, it is preferable that the value when curl is represented by the following numerical formula (e) is in the range of −15 to +15, more preferably in the range of −12 to +12, and −10 A range of +10 is more preferable.
In this case, the measurement direction of the curl in the sample is measured in the conveyance direction of the base material in the case of application in a web form. In the following mathematical formula (e), R represents a radius of curvature (m).
Carl = 1 / R ... Formula (e)

If the curl is small and the curl value is within the above range, it is preferable that cracks and film peeling do not occur in the production, processing and handling of the film having a coating layer. It is possible to reduce the curl within the above range and increase the surface hardness by setting the volume shrinkage ratio before and after curing to 15% or less.
The curl is measured using the curl measurement template of Method A in “Measuring Method of Curling of Photographic Film” of JIS K-7619-1988. The measurement conditions are 25 ° C., humidity 60% RH, and humidity control time 10 hours. Here, “curl plus” means a curl in which the coating layer coating side of the film is inside the curve, and “minus” means a curl in which the coating side is outside the curve.

  Further, the protective film A of the present invention preferably has an absolute value of the difference between the curl values of 24 to 0 when only the humidity is changed from 80% RH to 10% RH based on the curl measurement method. More preferably, it is 15-0, and it is still more preferable that it is 8-0. This is a property related to handling, peeling, and cracking when a protective film is applied under various humidity conditions.

  As for the crack resistance of the protective film A of the present invention, the radius of curvature at which cracking occurs when the coating layer coating side is rolled outward is preferably 30 mm or less, more preferably 25 mm or less, and 20 mm or less. Is more preferable. About the crack of an edge part, it is preferable that there is no crack or the length of a crack is less than 1 mm on average. This crack resistance is an important characteristic for preventing cracking defects during handling such as coating, processing, cutting, and sticking of a film having a coating layer.

  In the coating layer of the protective film A of the present invention, additives such as a heat stabilizer, a light stabilizer and a lubricant can be used as necessary.

<< Hard coat layer >>
In the protective film A of the present invention, a layer having a hard coat property (hereinafter sometimes referred to as a hard coat layer) is provided on one surface of the transparent support in order to impart physical strength of the protective film. It is preferable to be provided.
The hard coat layer is preferably a light-scattering layer having light scattering properties on the surface and / or inside (when the surface is provided with scattering properties, it may be referred to as an antiglare layer).

<< Antireflection Layer >>
Further, in the protective film A of the present invention, it is preferable to reduce the reflectance by providing at least a low refractive index layer as an antireflection layer on the hard coat layer. It is more preferable in terms of reflectance reduction to provide an antireflection layer comprising a plurality of layers provided with a low refractive index layer in addition to the high refractive index layer.
Although an antireflection layer can be provided without providing a hard coat layer, it is preferable to interpose a hard coat layer in order to improve the physical strength of the protective film. The hard coat layer may have a laminated structure of two or more layers.

  Hereinafter, the hard coat layer and the antireflection layer formed in the present invention will be described. In the present invention, various types of layers can be provided as the coating layer, and the requirements for the hard coat layer may differ depending on the type of the coating layer, and individual descriptions are described in the description of the coating layer. The contents common to are described.

[Layer structure of hard coat layer and antireflection layer]
As a preferred embodiment, the refractive index, the film thickness, the number of layers, the layer order, etc. are set so that the reflectance is reduced by optical interference on a transparent base film or a coating layer provided with a hard coat layer. The structure laminated | stacked in consideration is mentioned.
The simplest configuration of the antireflection layer is a configuration in which only the low refractive index layer is coated on the hard coat layer. In order to further reduce the reflectance, the antireflection layer is composed of a combination of a high refractive index layer having a higher refractive index than that of the transparent substrate film and a low refractive index layer having a lower refractive index than that of the transparent substrate film. Is preferred.
As a structural example, two layers of a high refractive index layer / low refractive index layer from the transparent base film side, or three layers having different refractive indices are used as a medium refractive index layer (a transparent base film or a hard coat layer). Some layers have a high refractive index and a lower refractive index than the high refractive index layer) / high refractive index layer / low refractive index layer, and so on. Has been.
Among them, from the viewpoint of durability, optical characteristics, cost, productivity, etc., it is preferable to apply a medium refractive index layer / high refractive index layer / low refractive index layer in this order on a transparent substrate film having a hard coat layer. JP-A-8-122504, JP-A-8-110401, JP-A-10-300902, JP-A-2002-243906, JP-A-2000-11706 and the like.
Other functions may be imparted to each layer, for example, an antifouling low refractive index layer or an antistatic high refractive index layer (eg, JP-A-10-206603, JP-A-2002). -243906 publication etc.) etc. are mentioned.

  Examples of preferred layer configurations of the hard coat layer and antireflection layer of the present invention are shown below. The antireflection film of the present invention is not particularly limited to these layer configurations as long as the reflectance can be reduced by optical interference. In the following configuration, the transparent substrate film has a coating layer formed on at least one of the hard coat layer and / or the antireflection layer side or the opposite side, and includes the coating layer as a transparent substrate film. In the following constitution, the antiglare layer preferably basically has a hard coat property, but when it is used by being laminated with a hard coat layer, it may not have a hard coat property. In order to improve the hard coat property and control the surface form, it is also preferable to use a laminate of an antiglare layer having a hard coat property and a hard coat layer.

Transparent substrate film / low refractive index layerTransparent substrate film / antistatic layer / low refractive index layerTransparent substrate film / antiglare layer / low refractive index layerTransparent substrate film / antiglare layer / antistatic Layer / low refractive index layer / transparent substrate film / hard coat layer / antiglare layer / low refractive index layer / transparent substrate film / hard coat layer / antiglare layer / antistatic layer / low refractive index layer / transparent substrate Film / hard coat layer / antistatic layer / antiglare layer / low refractive index layer / transparent substrate film / hard coat layer / high refractive index layer / low refractive index layer / transparent substrate film / hard coat layer / antistatic layer / High refractive index layer / Low refractive index layer / transparent substrate film / Hard coat layer / Medium refractive index layer / High refractive index layer / Low refractive index layer / Transparent substrate film / Anti-glare layer / High refractive index layer / Low Refractive index layer / transparent substrate film / antiglare layer / medium refractive index layer / high refractive index layer / low refractive index layer / transparent substrate Film / Antistatic layer / Hard coat layer / Medium refractive index layer / High refractive index layer / Low refractive index layer / Antistatic layer / Transparent substrate film / Hard coat layer / Medium refractive index layer / High refractive index layer / Low refractive index Index layer / transparent substrate film / antistatic layer / antiglare layer / medium refractive index layer / high refractive index layer / low refractive index layer / antistatic layer / transparent substrate film / antiglare layer / medium refractive index layer / high Refractive index layer / low refractive index layer / antistatic layer / transparent substrate film / antiglare layer / high refractive index layer / low refractive index layer / high refractive index layer / low refractive index layer

  Further, as another aspect, an aspect in which a layer necessary for the purpose of imparting hard coat property, antifouling property and the like is provided without actively using optical interference is also preferable.

  The example of the preferable layer structure of the film of the said aspect is shown below. In the following configuration, the transparent substrate film has a moisture-proof layer formed on at least one side of the hard coat layer and / or the antireflection layer or the opposite side, and includes the coating layer to form a transparent substrate film. In the following constitution, the antiglare layer preferably basically has a hard coat property, but when it is used by being laminated with a hard coat layer, it may not have a hard coat property. In order to improve the hard coat property and control the surface form, it is also preferable to use a laminate of an antiglare layer having a hard coat property and a hard coat layer.

Transparent substrate film / hard coat layer Transparent substrate film / hard coat layer / hard coat layerTransparent substrate film / antiglare layerTransparent substrate film / antiglare layer / antiglare layerTransparent substrate film / Hard coat layer / antiglare layer / transparent substrate film / antiglare layer / hard coat layer / transparent substrate film / antistatic layer / transparent substrate film / antistatic layer / hard coat layer / transparent substrate film / hard coat Layer / antifouling layer / antistatic layer / transparent substrate film / hard coat layer / antistatic layer / transparent substrate film / antiglare layer / antiglare layer / transparent substrate film / antistatic layer

  These layers can be formed by methods such as vapor deposition, atmospheric pressure plasma, and coating. From the viewpoint of productivity, it is preferably formed by coating.

[Physical properties of hard coat layer]
The refractive index of the hard coat layer in the present invention is preferably in the range of 1.48 to 2.00 from the optical design for obtaining an antireflection film, and preferably 1.49 to 1.90. More preferably, it is in the range of 1.50 to 1.80. In an embodiment in which at least one low refractive index layer is provided on the hard coat layer, which is a preferred embodiment of the present invention, the antireflection property is lowered if the refractive index is too small, and the color of the reflected light is too large. Tend to be stronger.
From the viewpoint of imparting sufficient durability and impact resistance to the film, the thickness of the hard coat layer is preferably about 0.5 to 50 μm, more preferably 1 to 20 μm, further preferably 2 to 15 μm, and 3 to 12 μm. Is particularly preferred.
Further, the strength of the hard coat layer is preferably H or more, more preferably 2H or more, and further preferably 3H or more in a pencil hardness test.
Furthermore, in the Taber test according to JIS K5400, the smaller the wear amount of the test piece before and after the test, the better.

The hard coat layer is preferably formed by a crosslinking reaction or a polymerization reaction of an ionizing radiation curable compound. For example, it may be formed by coating a coating composition containing an ionizing radiation-curable polyfunctional monomer or polyfunctional oligomer on a transparent support and subjecting the polyfunctional monomer or polyfunctional oligomer to a crosslinking reaction or a polymerization reaction. it can.
The functional group of the ionizing radiation-curable polyfunctional monomer or polyfunctional oligomer is preferably a light, electron beam, or radiation polymerizable group, and among them, a photopolymerizable functional group is preferable.
Examples of the photopolymerizable functional group include unsaturated polymerizable functional groups such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among them, a (meth) acryloyl group is preferable.

In place of or in addition to the monomer having a polymerizable unsaturated group, a crosslinkable functional group may be introduced into the binder.
Examples of the crosslinkable functional group include isocyanate group, epoxy group, aziridine group, oxazoline group, aldehyde group, carbonyl group, hydrazine group, carboxyl group, methylol group and active methylene group. Vinylsulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester and urethane, and metal alkoxide such as tetramethoxysilane can also be used as a monomer having a crosslinked structure. A functional group that exhibits crosslinkability as a result of the decomposition reaction, such as a block isocyanate group, may be used. That is, in the present invention, the crosslinkable functional group may not react immediately but may exhibit reactivity as a result of decomposition. These binders having a crosslinkable functional group can form a crosslinked structure by heating after coating.

  The hard coat layer contains matte particles having an average particle diameter of 1.0 to 15.0 μm, preferably 1.5 to 10.0 μm, such as inorganic compound particles or resin particles, for the purpose of imparting internal scattering properties. May be.

  For the purpose of controlling the refractive index of the hard coat layer, a high refractive index monomer, inorganic particles, or both can be added to the binder of the hard coat layer. In addition to the effect of controlling the refractive index, the inorganic particles also have the effect of suppressing cure shrinkage due to the crosslinking reaction. In the present invention, a polymer formed by polymerizing the polyfunctional monomer and / or the high refractive index monomer after the formation of the hard coat layer, and the inorganic particles dispersed therein are referred to as a binder.

The haze of the hard coat layer varies depending on the function imparted to the protective film.
When maintaining the sharpness of the image, suppressing the reflectance of the surface, and not imparting the light scattering function inside and on the surface of the hard coat layer, the haze value is preferably as low as possible, specifically 10% or less is preferable, 5% or less is more preferable, and 2% or less is still more preferable.

On the other hand, when the antiglare function is imparted by surface scattering of the hard coat layer, the surface haze is preferably 0.5 to 15%, more preferably 1 to 10%.
In addition, when it is difficult to see the pattern, color unevenness, brightness unevenness, glare, etc. of the liquid crystal panel due to internal scattering of the hard coat layer, or to add the function of expanding the viewing angle by scattering, the internal haze value (from the total haze value) The value obtained by subtracting the surface haze value) is preferably 10 to 90%, more preferably 15 to 80%, and still more preferably 20 to 70%.
The film of the present invention can freely set surface haze and internal haze according to the purpose.

  In addition, for the surface irregularity shape of the hard coat layer, in order to obtain a clear surface for the purpose of maintaining the sharpness of the image, among the characteristics indicating the surface roughness, for example, the centerline average roughness (Ra) is set. The thickness is preferably 0.08 μm or less, more preferably 0.07 μm or less, and further preferably 0.06 μm or less. In the film of the present invention, the surface unevenness of the hard coat layer is dominant to the surface unevenness of the film, and the center line average roughness of the antireflection film is adjusted by adjusting the center line average roughness of the hard coat layer. It can be set as the said range.

  In order to maintain the sharpness of the image, it is preferable to adjust the clarity of the transmitted image in addition to adjusting the uneven shape of the surface. The clearness of the transmitted image of the clear antireflection film is preferably 60% or more. The transmitted image clarity is generally an index indicating the degree of blurring of an image reflected through a film, and the larger this value, the clearer and better the image viewed through the film. The transmitted image definition is preferably 70% or more, and more preferably 80% or more.

<< Surface Improvement Agent >>
The coating liquid used to produce any layer on the support has at least one of fluorine and silicone surfaces to improve surface defects (coating irregularities, drying irregularities, point defects, etc.) It is preferable to add a state improver.

The surface improver preferably changes the surface tension of the coating solution by 1 mN / m or more.
Here, when the surface tension of the coating liquid changes by 1 mN / m or more, the surface tension of the coating liquid after the addition of the surface conditioner is added, including the concentration process during coating / drying. It means that it changes by 1 mN / m or more as compared with the surface tension of the coating liquid that has not been applied.
It is preferably a surface improver that has the effect of lowering the surface tension of the coating solution by 1 mN / m or more, more preferably a surface improver that lowers by 2 mN / m or more, and a surface improver that lowers by 3 mN / m or more. More preferably it is.

  Preferable examples of the fluorine-based surface improver include compounds containing a fluoroaliphatic group. Examples of preferred compounds include those described in JP-A-2005-115359, JP-A-2005-221963, and JP-A-2005-234476.

<< Anti-glare layer >>
The antiglare layer is formed for the purpose of contributing to the film antiglare properties due to surface scattering and preferably hard coat properties for improving the scratch resistance of the film. Therefore, in this invention, it can be used as one embodiment of a hard-coat layer.

  As a method for imparting anti-glare properties, a method of laminating and forming a mat-shaped shaping film having fine irregularities on the surface as described in JP-A-6-16851, as described in JP-A-2000-206317 A method of forming by curing shrinkage of an ionizing radiation curable resin due to a difference in the amount of ionizing radiation applied, and by reducing the mass ratio of a good solvent to a light transmitting resin by drying as described in JP-A No. 2000-338310. A method of solidifying a light-sensitive fine particle and a translucent resin while gelling to form unevenness on the surface of the coating film, a method of imparting surface unevenness by external pressure as described in JP-A-2000-275404, A method for imparting surface irregularities by external pressure as described in Kai 2000-275404, and a mixture of a plurality of polymers as described in JP-A-2005-195819. How the solvent from the solution to form a surface unevenness by utilizing the fact that the phase separation in the process of evaporation, are known, such as, can use these known methods.

[Translucent particles]
One preferred embodiment of the antiglare layer that can be used in the present invention contains, as essential components, a binder that can impart hard coat properties, translucent particles for imparting antiglare properties, and a solvent. Surface irregularities are formed by the protrusions of the light-transmitting particles themselves or the protrusions formed of an aggregate of a plurality of particles. The antiglare layer having antiglare properties preferably has both antiglare properties and hard coat properties.

Specific examples of the translucent particles include inorganic compound particles such as silica particles and TiO ₂ particles; resin particles such as acrylic particles, crosslinked acrylic particles, polystyrene particles, crosslinked styrene particles, melamine resin particles, and benzoguanamine resin particles. Are preferred. Of these, crosslinked styrene particles, crosslinked acrylic particles, and silica particles are preferred. The shape of the mat particle can be either spherical or indefinite.

Two or more kinds of mat particles having different particle diameters may be used in combination. It is possible to impart anti-glare properties with mat particles having a larger particle size and to impart other optical characteristics with mat particles having a smaller particle size. For example, when an anti-glare antireflection film is attached to a high-definition display of 133 ppi or higher, a problem in display image quality called “glare” may occur.
“Glitter” is derived from the fact that pixels are enlarged or reduced due to unevenness present on the surface of the antiglare and antireflection antireflection film, resulting in loss of luminance uniformity, but particles smaller than mat particles that impart antiglare properties. It can be greatly improved by using mat particles having a diameter different from that of the binder.

The mat particles, matting particle amount in the formed antiglare hard coat layer is preferably be contained 10~1,000mg / ^{m 2,} it is more preferably contained 100 to 700 mg / ^{m 2.}

  The film thickness of the antiglare layer is preferably 1 to 20 μm, and more preferably 2 to 10 μm. By setting it within the above range, hard coat properties, curling, and brittleness can be satisfied.

  On the other hand, the center line average roughness (Ra) of the antiglare layer is preferably in the range of 0.09 to 0.40 μm. If it exceeds 0.40 μm, problems such as glare and whitening of the surface when external light is reflected occur. Further, it is preferable that the value of the transmitted image definition is 5 to 60%.

  The strength of the antiglare layer is preferably H or more, more preferably 2H or more, and further preferably 3H or more in a pencil hardness test.

[Phase separation]
As an example of a technique for imparting anti-glare properties other than expressing anti-glare properties using translucent particles that can be used in the present invention, unevenness is formed on the surface of the coating film by spinodal decomposition of a plurality of polymers. A method is mentioned.
Moreover, it becomes possible to give favorable light diffusibility by giving a difference in the refractive index of the phase isolate | separated especially.
The light scattering layer formed by spinodal decomposition is composed of a plurality of polymers having different refractive indexes, and is usually a phase having at least a co-continuous phase structure in an operating atmosphere (especially at room temperature of about 10 to 30 ° C.). A separation structure is formed.
The co-continuous phase structure is formed by spinodal decomposition from a liquid phase containing a plurality of polymers (liquid phase at room temperature, for example, a mixed liquid or a solution).
The bicontinuous phase structure is usually formed by spinodal decomposition through evaporation of a solvent using a composition (for example, a mixed solution or a solution) containing a plurality of polymers and forming a liquid phase at room temperature.
Since such a light scattering layer is formed from a liquid phase, it has a uniform and fine co-continuous phase structure.
When such a transmissive light scattering sheet is used, incident light is substantially isotropically scattered, and directivity can be imparted to the transmitted scattered light. Therefore, both high light scattering and directivity can be achieved.

  In order to enhance light scattering properties, a plurality of polymers can be used in combination so that the difference in refractive index is, for example, about 0.01 to 0.2, and preferably about 0.1 to 0.15. If the difference in refractive index is less than 0.01, the intensity of the transmitted scattered light decreases. If the difference in refractive index is greater than 0.2, high directivity cannot be imparted to the transmitted scattered light.

  The plurality of polymers include, for example, styrene resins, (meth) acrylic resins, vinyl ester resins, vinyl ether resins, halogen-containing resins, olefin resins (including alicyclic olefin resins), polycarbonate resins, and polyesters. Resin, polyamide resin, thermoplastic polyurethane resin, polysulfone resin (polyethersulfone, polysulfone, etc.), polyphenylene ether resin (2,6-xylenol polymer, etc.), cellulose derivatives (cellulose esters, cellulose carbamates) , Cellulose ethers, etc.), silicone resins (polydimethylsiloxane, polymethylphenylsiloxane, etc.), rubbers or elastomers (diene rubbers such as polybutadiene, polyisoprene, styrene-butadiene copolymers, Acrylonitrile - butadiene copolymer, acrylic rubber, urethane rubber, silicone rubber, etc.) can be chosen a suitable combination and the like.

  Preferred polymers include, for example, styrene resins, (meth) acrylic resins, vinyl ester resins, vinyl ether resins, halogen-containing resins, alicyclic olefin resins, polycarbonate resins, polyester resins, polyamide resins, Cellulose derivatives, silicone resins, rubbers or elastomers are included. As the plurality of polymers, a resin that is non-crystalline and is soluble in an organic solvent (in particular, a common solvent capable of dissolving the plurality of polymers) is usually used. In particular, resins with high moldability or film formability, transparency and weather resistance, such as styrene resins, (meth) acrylic resins, alicyclic olefin resins, polyester resins, cellulose derivatives (cellulose esters, etc.) Etc. are preferable.

  These plural polymers can be used in appropriate combinations. For example, in a combination of polymers, at least one polymer may be converted to a cellulose derivative, particularly a cellulose ester (eg, cellulose C2-4 alkylcarboxyl such as cellulose diacetate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, etc. Acid esters) and may be combined with other polymers.

  The glass transition temperature of the polymer is preferably, for example, −100 to 250 ° C., more preferably −50 to 230 ° C., still more preferably about 0 to 200 ° C., and particularly preferably about 50 to 180 ° C. From the viewpoint of sheet strength and rigidity, the glass transition temperature of at least one of the constituent polymers is 50 ° C. or higher (for example, about 70 to 200 ° C.), preferably 100 ° C. or higher (for example, 100 to 170 ° C.). It is advantageous that The mass average molecular weight of the polymer can be selected from the range of, for example, about 1,000,000 or less (about 10,000 to 1,000,000), preferably about 10,000 to 700,000.

  In the present invention, a wet method is employed in which a solvent is evaporated from a liquid phase containing a plurality of polymers to perform spinodal decomposition, and therefore, in principle, substantially isotropic regardless of the compatibility of the plurality of polymers. A light scattering layer having a co-continuous phase structure can be formed. For this reason, it may be configured by combining a plurality of mutually compatible polymers. However, in order to easily control the phase separation structure by spinodal decomposition and to form a co-continuous phase structure efficiently, incompatible (phase separation) In many cases, a plurality of polymers are combined.

  The plurality of polymers can be constituted by a combination of the first polymer and the second polymer, and each of the first polymer and the second polymer may be constituted by a single resin or a plurality of resins. Also good. The combination of the first polymer and the second polymer is not particularly limited. For example, when the first polymer is a cellulose derivative (for example, cellulose esters such as cellulose acetate propionate), the second polymer is a styrene resin (polystyrene, styrene-acrylonitrile copolymer, etc.), (meta ) Acrylic resins (such as polymethyl methacrylate), alicyclic olefin resins (such as polymers using norbornene as monomers), polycarbonate resins, polyester resins (such as poly C2-4 alkylene arylate copolyester) Or the like.

  The ratio (mass ratio) between the first polymer and the second polymer is preferably, for example, first polymer / second polymer = about 10/90 to 90/10, and about 20/80 to 80/20. More preferably, about 30/70 to 70/30 is still more preferable, and about 40/60 to 60/40 is particularly preferable. When the ratio of one polymer is too large, the volume ratio between the separated phases is biased, so that the intensity of scattered light decreases. In addition, when forming a sheet | seat with a 3 or more some polymer, 1-90 mass% is preferable, as for content of each polymer, 1-70 mass% is more preferable, 5-70 mass% is still more preferable, 10-70 mass% 70% by mass is particularly preferred.

The light scattering layer constituting the light scattering sheet of the present invention has at least a co-continuous phase structure. The co-continuous phase structure is sometimes referred to as a co-continuous structure or a three-dimensional continuous or connected structure, and means a structure in which at least two constituent polymer phases are continuous (for example, a network structure). .
The light scattering layer only needs to have at least a co-continuous phase structure, and may have a structure in which a co-continuous phase structure and a droplet phase structure (independent or isolated phase structure) are mixed. In spinodal decomposition, a co-continuous phase structure is formed with the progress of phase separation, and when the phase separation is further advanced, the continuous phase becomes discontinuous by its surface tension, resulting in a droplet phase structure (spherical, true spherical) Sea island structure of independent phases).
Therefore, depending on the degree of phase separation, an intermediate structure between the co-continuous phase structure and the droplet phase structure, that is, a phase structure in the process of shifting from the co-continuous phase to the droplet phase can be formed.
In the present invention, the intermediate structure is also referred to as a co-continuous phase structure. When the phase separation structure is a mixed structure of a co-continuous phase structure and a droplet structure, the ratio of the droplet phase (independent polymer phase) is, for example, 30% or less (volume ratio), preferably 10% or less ( Volume ratio). The shape of the co-continuous phase structure is not particularly limited, and may be a network shape, particularly a random network shape.

  The bicontinuous phase structure is generally isotropic with reduced anisotropy in the layer or sheet plane. Note that isotropic means that the average interphase distance of the co-continuous phase structure is substantially equal in any direction in the sheet plane.

The bicontinuous phase structure usually has regularity in the interphase distance (distance between the same phases). For this reason, the light scattered on the sheet is directed to a specific direction by Bragg reflection.
Therefore, even when mounted on a reflective liquid crystal display device, the transmitted scattered light can be directed in a certain direction, the display screen can be made highly bright, and a conventional particle-dispersed transmissive light scattering sheet Thus, a problem that cannot be solved, that is, reflection of a light source (for example, a fluorescent lamp) on the panel can be avoided.

  In the light scattering sheet, the average interphase distance between the co-continuous phases is preferably 0.5 to 20 μm, more preferably 1 to 20 μm, still more preferably 1 to 15 μm, and particularly preferably 1 to 10 μm. If the average interphase distance is too small, it is difficult to obtain high scattered light intensity, and if the average interphase distance is too large, the directivity of transmitted scattered light decreases.

  The average interphase distance of the co-continuous layer can be calculated from a photomicrograph (such as a transmission microscope, a phase contrast microscope, or a confocal laser microscope) of the light scattering layer or light scattering sheet. In addition, the scattering angle θ at which the scattered light intensity is maximized is measured by a method similar to the scattered light directivity evaluation method described later, and the average interphase distance d of the co-continuous phase is calculated from the following Bragg reflection condition equation. May be.

2d · sin (θ / 2) = λ
(Where d is the average interphase distance of co-continuous phases, θ is the scattering angle, and λ is the wavelength of light)

[Formation of light scattering layer by embossing method]
As an example of a method for creating a light scattering layer, a method for forming a light scattering layer by an embossing method can be given as an example of a method other than the use of translucent particles to exhibit antiglare properties.
The light scattering layer prepared by the embossing method is an ionizing radiation curable resin composition or a thermosetting resin composition formed on a transparent substrate with a mat-shaped molding film having fine irregularities on the surface. A light diffusion layer consisting essentially of is formed.
When the resin is an ionizing radiation curable resin composition, the light scattering layer is produced by coating the ionizing radiation curable resin composition on a transparent substrate and then applying the ionizing radiation curable resin. By laminating a mat-shaped shaped film having fine irregularities on the surface of the uncured coating film of the composition, and then irradiating ionizing radiation on the coated film on which the shaped film is laminated, It is preferable to manufacture the coating film of the ionizing radiation curable resin composition by a manufacturing method in which the shaped film is peeled from the cured coating film of the ionizing radiation curable resin.
When the resin is a thermosetting resin composition, the thermosetting resin composition is applied on a transparent substrate, and then the uncured coating film of the applied thermosetting resin composition is applied. A mat-like shaped film having fine irregularities on the surface is laminated, and then the coating film laminated with the shaped film is heated and cured, and then the cured thermosetting resin composition is applied. It is preferable to manufacture by the manufacturing method which peels a shaping film from a film | membrane.

When laminating the shaping film on the coating film of the uncured ionizing radiation curable resin composition, if the coated resin is of a solvent dilution type, the solvent is dried and then laminating, If the applied resin is solventless, lamination is performed as it is.
The film forming component of the ionizing radiation curable resin composition used for the light diffusing layer of the embossing method is preferably one having an acrylate functional group, for example, a relatively low molecular weight polyester resin, polyether resin, acrylic resin , Epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, oligomers or prepolymers of polyfunctional compounds such as polyhydric alcohols or prepolymers and ethyl (meth) as a reactive diluent Monofunctional monomers such as acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone and polyfunctional monomers such as trimethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripro Lenglycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) ) Those containing a relatively large amount of acrylate or the like can be used.

  Particularly preferably, a mixture of polyester acrylate and polyurethane acrylate is used. The reason is that polyester acrylate is very hard and suitable for obtaining a hard coat, but polyester acrylate alone has low impact and is brittle. In order to give the properties, polyurethane acrylate is used in combination. The blending ratio of polyurethane acrylate to 100 parts by mass of polyester acrylate is 30 parts by mass or less. If this value is exceeded, the coating film is too soft and the hardness is lost.

  Furthermore, in order to make the ionizing radiation curable resin composition into an ultraviolet curable resin composition, acetophenones, benzophenones, Michler benzoylbenzoate, α-amyloxime ester, tetra Methyl thiuram monosulfide, thioxanthones, and n-butylamine, triethylamine, tri-n-butylphosphine, and the like can be used as a photosensitizer. In particular, in the present invention, it is preferable to mix urethane acrylate as an oligomer and dipentaerythritol hexa (meth) acrylate as a monomer.

[High refractive index layer and medium refractive index layer]
When the protective film of the present invention is provided with a high refractive index layer and a medium refractive index layer and optical interference is used together with a low refractive index layer described later, the antireflection property can be enhanced.
In the following specification, the high refractive index layer and the middle refractive index layer may be collectively referred to as a high refractive index layer. In the present invention, “high”, “medium”, and “low” in the high refractive index layer, medium refractive index layer, and low refractive index layer represent the relative refractive index relationship between the layers. In terms of the relationship with the transparent support, the refractive index preferably satisfies the relationship of transparent support> low refractive index layer, high refractive index layer> transparent support.
In the present specification, the high refractive index layer, the middle refractive index layer, and the low refractive index layer may be collectively referred to as an antireflection layer.

  In order to construct an antireflection layer by constructing a low refractive index layer on the high refractive index layer, the refractive index of the high refractive index layer is preferably 1.55 to 2.40, and 1.60. To 2.20 is more preferable, 1.65 to 2.10 is more preferable, and 1.80 to 2.00 is particularly preferable.

  When an antireflective film is prepared by coating a medium refractive index layer, a high refractive index layer, and a low refractive index layer in order from the support, the refractive index of the high refractive index layer is 1.65 to 2.40. Preferably, it is 1.70-2.20. The refractive index of the middle refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the middle refractive index layer is preferably 1.55-1.80.

Specific examples of the inorganic particles used in the high refractive index layer and the medium refractive index layer include TiO ₂ , ZrO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO and SiO _2. Etc. TiO ₂ and ZrO ₂ are particularly preferable in terms of increasing the refractive index. The inorganic filler is preferably subjected to a silane coupling treatment or a titanium coupling treatment on the surface, and a surface treatment agent having a functional group capable of reacting with a binder species on the filler surface is preferably used.

The content of inorganic particles in the high refractive index layer is preferably 10 to 90 mass%, more preferably 15 to 80 mass%, and more preferably 15 to 75 mass% with respect to the mass of the high refractive index layer. More preferably. Two or more kinds of inorganic particles may be used in combination in the high refractive index layer.
When the low refractive index layer is provided on the high refractive index layer, the refractive index of the high refractive index layer is preferably higher than the refractive index of the transparent support.
The high refractive index layer contains an ionizing radiation curable compound containing an aromatic ring, an ionizing radiation curable compound containing a halogenated element other than fluorine (for example, Br, I, Cl, etc.), and atoms such as S, N, P, etc. A binder obtained by a crosslinking or polymerization reaction such as an ionizing radiation curable compound is also preferably used.

  The film thickness of the high refractive index layer can be appropriately designed depending on the application. When using a high refractive index layer as an optical interference layer described later, 30 to 200 nm is preferable, 50 to 170 nm is more preferable, and 60 to 150 nm is still more preferable.

  The haze of the high refractive index layer is preferably as low as possible when it does not contain particles that impart an antiglare function. It is preferably 5% or less, more preferably 3% or less, still more preferably 1% or less. The high refractive index layer is preferably constructed directly on the transparent support or via another layer.

[Low refractive index layer]
In order to reduce the reflectance of the film of the present invention, it is preferable to use a low refractive index layer.
The refractive index of the low refractive index layer is preferably 1.20 to 1.46, more preferably 1.25 to 1.46, and still more preferably 1.30 to 1.40.
The thickness of the low refractive index layer is preferably 50 to 200 nm, and more preferably 70 to 100 nm.
The haze of the low refractive index layer is preferably 3% or less, more preferably 2% or less, and still more preferably 1% or less. The specific strength of the low refractive index layer is preferably H or more, more preferably 2H or more, and further preferably 3H or more in a pencil hardness test under a 500 g load.
Moreover, in order to improve the antifouling performance of the protective film, the surface contact angle with respect to water is preferably 90 ° or more, more preferably 95 ° or more, and further preferably 100 ° or more.
Preferred embodiments of the composition of the low refractive index layer include (1) a composition containing a fluorine-containing polymer having a crosslinkable or polymerizable functional group, and (2) a hydrolysis condensate of a fluorine-containing organosilane material. And (3) a composition containing a monomer having two or more ethylenically unsaturated groups and inorganic fine particles having a hollow structure.

(1) Fluorine-containing compound having a crosslinkable or polymerizable functional group As the fluorine-containing compound having a crosslinkable or polymerizable functional group, co-polymerization of a fluorine-containing monomer and a monomer having a crosslinkable or polymerizable functional group Coalescence is mentioned. Examples of the fluorine-containing monomer include fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole, etc.) (meta ) Partially or fully fluorinated alkyl ester derivatives of acrylic acid (for example, Biscoat 6FM (manufactured by Osaka Organic Chemicals) or M-2020 (manufactured by Daikin)), fully or partially fluorinated vinyl ethers, and the like.

As one example of the monomer for imparting a crosslinkable group, a (meth) acrylate monomer having a crosslinkable functional group in the molecule in advance, such as glycidyl methacrylate, can be mentioned.
Further, as another embodiment, after synthesizing a fluorine-containing copolymer using a monomer having a functional group such as a hydroxyl group, a monomer that further introduces a crosslinkable or polymerizable functional group by modifying those substituents is used. Is the method.
These monomers include (meth) acrylate monomers having a carboxyl group, hydroxyl group, amino group, sulfonic acid group, etc. (for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, etc.) Is mentioned. The latter embodiment is disclosed in Japanese Patent Laid-Open Nos. 10-25388 and 10-147739.

The fluorine-containing copolymer may contain a copolymerizable component as appropriate from the viewpoints of solubility, dispersibility, coating property, antifouling property, antistatic property and the like. In particular, for imparting antifouling properties and slipperiness, it is preferable to introduce silicone, and it can be introduced into both the main chain and the side chain.
The polysiloxane partial structure introduction method to the main chain is, for example, an azo group-containing polysiloxane amide described in JP-A-6-93100 (VPS-0501, 1001 (trade name; Wako Pure Chemical Industries, Ltd. And a method using a polymer-type initiator such as a company)).
Moreover, the method of introduce | transducing into a side chain is J. for example. Appl. Polym. Sci. As described in 2000, 78, 1955, JP-A-56-28219, etc., a polysiloxane having a reactive group at one end (for example, Silaplane series (manufactured by Chisso Corporation)) is introduced by a polymer reaction. The method can be synthesized by a method of polymerizing a polysiloxane-containing silicon macromer, and both methods are preferably used.

As described in JP 2000-17028 A, a curing agent having a polymerizable unsaturated group may be used in combination with the above polymer. Moreover, combined use with the compound which has a fluorine-containing polyfunctional polymerizable unsaturated group as described in Unexamined-Japanese-Patent No. 2002-145952 is also preferable. Examples of the compound having a polyfunctional polymerizable unsaturated group include monomers having two or more ethylenically unsaturated groups. Moreover, the hydrolysis-condensation product of the organolane described in Unexamined-Japanese-Patent No. 2004-170901 is also preferable, and the hydrolysis-condensation product of the organosilane containing a (meth) acryloyl group is especially preferable.
These compounds are particularly preferred because they have a large combined effect for improving scratch resistance, particularly when a compound having a polymerizable unsaturated group is used in the polymer body.

  When the polymer itself does not have sufficient curability, necessary curability can be imparted by blending a crosslinkable compound. For example, when the polymer body contains a hydroxyl group, various amino compounds are preferably used as the curing agent. The amino compound used as the crosslinkable compound is, for example, a compound containing one or both of a hydroxyalkylamino group and an alkoxyalkylamino group in total, specifically, for example, a melamine compound, Examples include urea compounds, benzoguanamine compounds, glycoluril compounds, and the like. For curing these compounds, an organic acid or a salt thereof is preferably used.

  Specific examples of these fluoropolymers are described in JP2003-222702A, JP2003-183322A, and the like.

(2) Hydrolyzed condensate of fluorine-containing organosilane material A composition containing a hydrolyzed condensate of a fluorine-containing organosilane compound as a main component is also preferable because of its low refractive index and high hardness on the coating film surface. A condensate of a tetraalkoxysilane with a compound containing hydrolyzable silanol at one or both ends with respect to the fluorinated alkyl group is preferred. The specific composition is described in Unexamined-Japanese-Patent No. 2002-265866, 317152.

(3) A composition containing a monomer having two or more ethylenically unsaturated groups and inorganic fine particles having a hollow structure As yet another preferred embodiment, a low refractive index layer comprising low refractive index particles and a binder can be mentioned. . The low refractive index particles may be organic or inorganic, but particles having pores inside are preferable. Specific examples of the hollow particles are described in the silica-based particles described in JP-A-2002-79616. The particle refractive index is preferably 1.15 to 1.40, more preferably 1.20 to 1.30. Examples of the binder include monomers having two or more ethylenically unsaturated groups described on the page of the light diffusion layer.

  It is preferable to add the polymerization initiator described in the page of the light scattering layer to the low refractive index layer of the present invention. When a radically polymerizable compound is contained, 1 to 10 parts by mass, preferably 1 to 5 parts by mass of a polymerization initiator can be used with respect to the compound.

  In the low refractive layer of the present invention, inorganic particles can be used in combination. In order to provide scratch resistance, 15 to 150% of the thickness of the low refractive index layer is preferable, 30 to 100% is more preferable, and fine particles having a particle diameter of 45 to 60% are more preferably used.

  In the low refractive index layer of the present invention, for the purpose of imparting properties such as antifouling property, water resistance, chemical resistance, and slipping property, a known polysiloxane-based or fluorine-based antifouling agent, slipping agent, etc. are appropriately used. Can be added.

<< Antistatic Layer >>
In the present invention, it is preferable to provide an antistatic layer from the viewpoint of preventing static electricity on the film surface.
The antistatic layer can be formed by, for example, applying a conductive coating solution containing conductive fine particles and a reactive curable resin, or depositing or sputtering a metal or metal oxide that forms a transparent film. Conventionally known methods such as a method of forming a conductive thin film can be mentioned.
The conductive layer can be formed directly on the support or via a primer layer that strengthens adhesion to the support. Further, the antistatic layer can be used as a part of the antireflection film. In this case, when used in a layer close to the outermost layer, sufficient antistatic properties can be obtained even if the film is thin.

The thickness of the antistatic layer is preferably from 0.01 to 10 μm, more preferably from 0.03 to 7 μm, still more preferably from 0.05 to 5 μm. The surface resistance of the antistatic layer is ^preferably from ¹⁰ 5 ~10 ¹² Ω / ^sq, more preferably 10 5 ~10 ⁹ Ω / ^sq, still to be 10 5 ~10 ⁸ Ω / sq preferable. The surface resistance of the antistatic layer can be measured by a four probe method.

The antistatic layer is preferably substantially transparent. Specifically, the haze of the antistatic layer is preferably 10% or less, more preferably 5% or less, still more preferably 3% or less, and particularly preferably 1% or less. .
Further, the transmittance of light having a wavelength of 550 nm is preferably 50% or more, more preferably 60% or more, further preferably 65% or more, and particularly preferably 70% or more.
The antistatic layer of the present invention has excellent strength, and the specific antistatic layer has a pencil hardness of 1 kg, preferably H or higher, more preferably 2H or higher, more preferably 3H or higher. It is more preferable that it is 4H or more.

<< Coating solvent >>
Among the above constituent layers, the layer applied adjacent to the transparent substrate film includes at least one solvent that dissolves the transparent substrate film and at least one solvent that does not dissolve the transparent substrate film. It is preferable to contain.
By setting it as such an aspect, the coexistence of the excessive penetration | infiltration of the adjacent layer component to a transparent base film and ensuring adhesiveness of an adjacent layer and a transparent base film can be aimed at.
Moreover, it is more preferable that at least one of the solvents that dissolve the transparent substrate film has a higher boiling point than at least one of the solvents that do not dissolve the transparent substrate film, and dissolves the transparent substrate film. It is more preferable that the boiling point temperature difference between the solvent having the highest boiling point and the solvent having the highest boiling point among the solvents that do not dissolve the transparent substrate film is 30 ° C. or more, and the difference in boiling point temperature is 40 ° C. or more. It is particularly preferred that

  The mass ratio (A / B) of the total amount (A) of the solvent that dissolves the transparent base film and the total amount (B) of the solvent that does not dissolve the transparent base film is preferably 5/95 to 50/50. -40/60 is more preferable, and 15 / 85-30 / 70 is still more preferable.

<< Formation of each layer >>
For the coating layer, hard coat layer, low refractive index layer, and other layers used in the present invention, a coating solution is applied on a transparent support, heated and dried, and then irradiated with light and / or as necessary. Alternatively, the monomer or curable resin for forming each layer is cured by heating. Thereby, each layer is formed.

  Although the coating method of each layer of the film of the present invention is not particularly limited, a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, an extrusion coating method (die coating method) ( U.S. Pat. No. 2,681,294) and known methods such as a micro gravure coating method are used, and among them, the micro gravure coating method and the die coating method are preferably used from the viewpoints of high productivity and coating film uniformity.

  Drying is preferably performed under conditions where the concentration of the organic solvent in the applied liquid film is 5% by mass or less after drying, more preferably 2% by mass or less, and even more preferably 1% by mass or less. Although the drying conditions are affected by the thermal strength and transport speed of the transparent substrate film, the length of the drying process, etc., it is preferable that the organic solvent content is as low as possible in terms of film hardness and adhesion prevention. When an organic solvent is not contained, the drying step can be omitted and ultraviolet irradiation can be performed immediately after coating.

  The coating layer of the present invention may be subjected to heat treatment in order to increase the crystallinity. The preferable heat treatment temperature is 40 to 130 ° C., and the heat treatment time can be appropriately determined according to the required crystallinity, but it is usually about 5 minutes to 48 hours.

Furthermore, for the purpose of improving the adhesion between the transparent substrate film and the coating layer, it is more preferable to perform a pretreatment such as a hydrophilization treatment or an uneven treatment on one or both sides of the transparent substrate film as desired.
Examples of the pretreatment include corona discharge treatment, glow discharge treatment, chromic acid treatment (wet), saponification treatment (wet), flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment, etc., but corona discharge treatment, glow discharge treatment. Saponification treatment (wet) is particularly preferred.

<< undercoat layer >>
In the present invention, it will be described that an undercoat layer is provided on both sides or one side of the coating layer. The undercoat layer may be composed of one layer or may be composed of two or more layers. In the present invention, it is more preferable to provide an undercoat layer having the following two-layer structure between the transparent support / coating layer.

[Composition of undercoat layer]
First layer: water-dispersible or water-soluble synthetic resin, and carbodiimide compound,
Antistatic layer second layer containing conductive metal oxide particles as essential components: Surface layer containing water-dispersible or water-soluble synthetic resin and cross-linking agent as essential components

The undercoat layer is provided with an antistatic layer and a surface layer in this order on a support. In the antistatic layer of the present invention, the haze of the low chargeable support obtained by providing the antistatic layer on the support is 3% or less, and the surface resistance of the surface layer of the resulting photosensitive material is 1 ×. Conductivity is imparted so as to be in the range of 10 ⁶ to 1 × 10 ¹¹ Ω. By providing the antistatic layer, it is possible to suppress the occurrence of trouble with dust caused by static electricity that occurs in the manufacturing process of handling the plastic support.

The antistatic layer is a layer containing conductive metal oxide particles, and generally further contains a binder.
The conductive metal oxide particles are preferably acicular particles having a major axis to minor axis ratio (major axis / minor axis) in the range of 3 to 50. More preferably, the minor axis is in the range of 10-50.
The minor axis of such acicular particles is preferably in the range of 0.001 to 0.1 μm, and more preferably in the range of 0.01 to 0.02 μm. The major axis is preferably in the range of 0.1 to 5.0 μm, and more preferably in the range of 0.1 to 2.0 μm.

Examples of the material of the conductive metal oxide particles include ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , MgO, BaO and MoO ₃ , and composite oxides thereof, and metal oxides thereof. In addition, metal oxides further containing different atoms can be mentioned.
As the metal oxide, SnO ₂ , ZnO, Al ₂ O ₃ , TiO ₂ , In ₂ O ₃ and MgO are preferable, SnO ₂ , ZnO, In ₂ O ₂ and TiO ₂ are more preferable, and SnO ₂ is particularly preferable. .
Examples of containing a small amount of different atoms include Zn or Al, In, TiO ₂ Nb or Ta, In ₂ O ₃ Sn, and SnO ₂ Sb, Nb or halogen elements. What doped 0.01-30 mol% (preferably 0.1-10 mol%) of an element is mentioned.
If the amount of the different element added is less than 0.01 mol%, sufficient conductivity cannot be imparted to the oxide or composite oxide. If it exceeds 30 mol%, the degree of blackening of the particles increases, and charging Since the prevention layer is dark, it is not suitable as a protective film.
Therefore, in the present invention, the material of the conductive metal oxide particles is preferably one containing a small amount of different elements with respect to the metal oxide or the composite metal oxide.
Moreover, what contains an oxygen defect in crystal structure is also preferable. As the conductive metal oxide particles containing a small amount of different atoms, antimony-doped SnO ₂ particles are preferable, and antimony-doped SnO ₂ particles are particularly preferable.
Accordingly, in the present invention, it is advantageous to use a metal oxide particle such as antimony-doped SnO ₂ having the short axis and long axis dimensions for forming an antistatic layer that is transparent and has good conductivity. is there. As a result, a protective film having a low chargeable support and having a surface layer having a surface electrical resistance in the range of 1 × 10 ⁶ to 1 × 10 ¹¹ Ω can be easily obtained.

About the reason why an antistatic layer which is transparent and has good conductivity can be advantageously formed by using acicular metal oxide particles having the dimensions of the short axis and the long axis (eg, antimony-doped SnO ₂ ). Is considered as follows.
In the antistatic layer, the needle-like metal oxide particles extend long in the major axis direction parallel to the surface of the antistatic layer, but the length of the minor axis in the thickness direction of the layer. It only occupies.
Since such acicular metal oxide particles are long in the major axis direction as described above, they are easier to contact with each other than ordinary spherical particles, and high conductivity can be obtained even in a small amount.
Accordingly, the surface electrical resistance can be reduced without impairing the transparency. Further, in the needle-like metal oxide particles, the minor axis diameter is usually smaller than or substantially the same as the thickness of the antistatic layer and rarely protrudes on the surface. Therefore, it is almost completely covered by the surface layer provided on the antistatic layer.
Accordingly, there can be obtained an advantage that there is almost no occurrence of powder falling that is a detachment of the protruding portion from the layer during the transport of the protective film.

The antistatic layer of the present invention generally contains a binder that disperses and supports conductive metal oxide particles.
As a material for the binder, various polymers such as an acrylic resin, a vinyl resin, a polyurethane resin, and a polyester resin can be used. From the viewpoint of preventing powder falling, a cured product of a polymer (preferably an acrylic resin, a vinyl resin, a polyurethane resin, or a polyester resin) and a carbodiimide compound is preferable.
In the present invention, from the viewpoint of maintaining a good working environment and preventing air pollution, it is preferable to use either a water-soluble polymer or a carbodiimide compound, or an aqueous dispersion such as an emulsion.
Further, the polymer has any group of a methylol group, a hydroxyl group, a carboxyl group, and an amino group so that a crosslinking reaction with the carbodiimide compound is possible. A hydroxyl group and a carboxyl group are preferred, and a carboxyl group is particularly preferred. The content of hydroxyl group or carboxyl group in the polymer is preferably 0.0001 to 1 equivalent / 1 kg, particularly preferably 0.001 to 1 equivalent / 1 kg.

Acrylic resins include acrylic acid esters such as acrylic acid and alkyl acrylate, homopolymers of monomers such as acrylamide, acrylonitrile, methacrylic acid esters such as methacrylic acid and alkyl methacrylate, methacrylamide and methacrylonitrile. Or the copolymer obtained by superposition | polymerization of 2 or more types of these monomers is mentioned.
Among these, homopolymers of monomers of acrylic acid esters such as alkyl acrylates and methacrylic acid esters such as alkyl methacrylates, or copolymers obtained by polymerization of two or more of these monomers preferable.
For example, the homopolymer of the monomer in any one of acrylic acid ester and methacrylic acid ester which has a C1-C6 alkyl group, or the copolymer obtained by superposition | polymerization of these 2 or more types of monomers is mentioned.
The acrylic resin has the above composition as a main component and, for example, partially uses a monomer having any group of a methylol group, a hydroxyl group, a carboxyl group, and an amino group so that a crosslinking reaction with a carbodiimide compound is possible. The resulting polymer.

Examples of the vinyl resin include polyvinyl alcohol, acid-modified polyvinyl alcohol, polyvinyl formal, polyvinyl butyral, polyvinyl methyl ether, polyolefin, ethylene / butadiene copolymer, polyvinyl acetate, vinyl chloride / vinyl acetate copolymer, vinyl chloride / ( And (meth) acrylic acid ester copolymers and ethylene / vinyl acetate copolymers (preferably ethylene / vinyl acetate / (meth) acrylic acid ester copolymers).
Among these, polyvinyl alcohol, acid-modified polyvinyl alcohol, polyvinyl polymer, polyolefin, ethylene / butadiene copolymer and ethylene / vinyl acetate copolymer (preferably ethylene / vinyl acetate / acrylic acid ester copolymer). Is preferred.
In the case of polyvinyl alcohol, acid-modified polyvinyl alcohol, polyvinyl formal, polyvinyl butyral, polyvinyl methyl ether, and polyvinyl acetate, for example, a vinyl alcohol unit is left in the polymer so that the vinyl resin can undergo a crosslinking reaction with a carbodiimide compound. Thus, the polymer having a hydroxyl group is used, and the other polymer is, for example, a crosslinkable polymer by partially using a monomer having any of a methylol group, a hydroxyl group, a carboxyl group, and an amino group.

Examples of the polyurethane resin include polyhydroxy compounds (eg, ethylene glycol, propylene glycol, glycerin, trimethylolpropane), aliphatic polyester polyols obtained by reaction of polyhydroxy compounds and polybasic acids, polyether polyols (eg, Poly (oxypropylene ether) polyol, poly (oxyethylene-propylene ether) polyol), polycarbonate-based polyol, and polyethylene terephthalate polyol, or a polyurethane derived from a mixture thereof and polyisocyanate can be used.
In the polyurethane resin, for example, the hydroxyl group remaining unreacted after the reaction between polyol and polyisocyanate can be used as a functional group capable of crosslinking reaction with a carbodiimide compound.

As the polyester resin, generally used is a polymer obtained by reacting a polyhydroxy compound (eg, ethylene glycol, propylene glycol, glycerin, trimethylolpropane) with a polybasic acid.
In the above-mentioned polyester resin, for example, the hydroxyl group and carboxyl group remaining unreacted after the reaction between the polyol and the polybasic acid can be used as a functional group capable of crosslinking reaction with the carbodiimide compound. Of course, a third component having a functional group such as a hydroxyl group may be added.

  Among the above polymers, acrylic resins and polyurethane resins are preferable, and acrylic resins are particularly preferable.

As the carbodiimide compound used in the present invention, it is preferable to use a compound part having a plurality of carbodiimide structures in the molecule.
Polycarbodiimide is usually synthesized by a condensation reaction of organic diisocyanate. Here, the organic group of the organic diisocyanate used for the synthesis of the compound having a plurality of carbodiimide structures in the molecule is not particularly limited, and either aromatic or aliphatic, or a mixed system thereof can be used. An aliphatic system is particularly preferred from the viewpoint of reactivity.
As the synthetic raw material, organic isocyanate, organic diisocyanate, organic triisocyanate and the like are used.
As examples of organic isocyanates, aromatic isocyanates, aliphatic isocyanates, and mixtures thereof can be used.

Specifically, 4,4′-diphenylmethane diisocyanate, 4,4-diphenyldimethylmethane diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane Diisocyanate, xylylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,3-phenylene diisocyanate, etc. are used. As organic monoisocyanates, isophorone isocyanate, phenyl isocyanate are used. Cyclohexyl isocyanate, butyl isocyanate, naphthyl isocyanate and the like are used.
Moreover, the carbodiimide type compound that can be used in the present invention is also available as a commercial product such as Carbodilite V-02-L2 (trade name: manufactured by Nisshinbo Co., Ltd.).
It is preferable to add the carbodiimide type compound of this invention in the range of 1-200 mass% with respect to a binder, and it is more preferable to add in the range of 5-100 mass%.

In order to form the antistatic layer of the present invention, first, for example, a dispersion obtained by dispersing the conductive metal oxide particles as they are or in a solvent such as water (including a dispersant and a binder as necessary) An antistatic layer-forming coating solution is prepared by adding and mixing (dispersing as necessary) an aqueous dispersion or aqueous solution containing the binder (eg, polymer, carbodiimide compound and appropriate additive).
The antistatic layer is a coating method generally known on the surface of a plastic film such as polyester (the side where no photosensitive layer is provided), such as dip coating, air knife coating, It can be applied by a curtain coating method, a wire bar coating method, a gravure coating method, an extrusion coating method or the like.
The plastic film such as polyester to be applied may be any of before sequential biaxial stretching, before simultaneous biaxial stretching, after uniaxial stretching and before re-stretching, or after biaxial stretching.
The surface of the plastic support on which the coating solution for forming the antistatic layer is preferably subjected to surface treatment such as ultraviolet treatment, corona treatment, glow discharge treatment and the like in advance.

The layer thickness of the antistatic layer of the present invention is preferably in the range of 0.01 to 1 μm, more preferably in the range of 0.01 to 0.2 μm. If the coating agent is less than 0.01 μm, it is difficult to uniformly apply the coating agent, and uneven coating tends to occur on the product. If it exceeds 1 μm, the antistatic performance and scratch resistance may be inferior.
The conductive metal oxide particles are preferably contained in the antistatic layer in the range of 10 to 1,000% by mass with respect to the binder (for example, the total of the polymer and the carbodiimide compound), More preferably, it is contained in the range of 500% by mass. If it is less than 10% by mass, sufficient antistatic properties cannot be obtained, and if it exceeds 1,000% by mass, the haze becomes too high.

The antistatic layer of the present invention and the following surface layer can be used in combination with additives such as a matting agent, a surfactant, and a slipping agent, if necessary.
Examples of the matting agent include particles of oxides such as silicon oxide, aluminum oxide, and magnesium oxide having a particle diameter of 0.001 to 10 μm, and particles such as a polymer or a copolymer such as polymethyl methacrylate and polystyrene. .
Examples of the surfactant include known anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants.
Examples of the slip agent include natural waxes such as carnauba wax, phosphate esters of higher alcohols having 8 to 22 carbon atoms or amino salts thereof; palmitic acid, stearic acid, behenic acid, and esters thereof; and silicone compounds. It is done.

  In the present invention, a surface layer is provided on the antistatic layer. The surface layer is provided mainly to assist the adhesion imparting with the adhesive layer and the anti-detachment function of the conductive metal oxide particles of the antistatic layer. As the material for the surface layer, various polymers such as acrylic resin, vinyl resin, polyurethane resin, and polyester resin can be generally used, and polymers described as the binder in the antistatic layer are preferable.

The crosslinking agent used for the surface layer is preferably an epoxy compound.
Examples of the epoxy compound include 1,4-bis (2 ′, 3′-epoxypropyloxy) butane, 1,3,5-triglycidyl isocyanurate, 1,3-diglycidyl-5- (γ-acetoxy-β-oxy Propyl) isosinurate, sorbitol polyglycidyl ethers, polyglycerol polyglycidyl ethers, pentaerythritol polyglycidyl ethers, diglycerol polyglycidyl ether, 1,3,5-triglycidyl (2-hydroxyethyl) isocyanurate, glycerol poly Epoxy compounds such as glycerol ethers and trimethylolpropane polyglycidyl ethers are preferable, and specific commercial products thereof include, for example, Denacol EX-521 and EX-614B (manufactured by Nagase Kasei Kogyo Co., Ltd.). , But it is not limited thereto.

  In addition, in the range of the addition amount that does not affect the optical characteristics, it can be used in combination with other compounds. E. K. Meers and T.W. H. "The Theory of the Photographic Process" by James, 3rd edition (1966), U.S. Patent Nos. 3316095, 3232264, 3288775, 27332303, 3635718, 3323716, 2732616, 258616 No. 3103437, No. 3017280, No. 2983611, No. 2725294, No. 2725295, No. 3100294, No. 3091537, No. 3321313, No. 3543292 and No. 312449, and British Patent Nos. 994869 and 1167207. The curing agent described in No. etc. is mentioned.

  Typical examples include melamine compounds containing two or more (preferably three or more) methylol groups and / or alkoxymethyl groups, and melamine resins or melamine urea resins, mucochloric acid, which are polycondensates thereof. Mucobromic acid, mucofenoxycyclolic acid, mucophenoxypromic acid, formaldehyde, glyoxal, monomethylglioxal, 2,3-dihydroxy-1,4-dioxane, 2,3-dihydroxy-5-methyl-1,4-dioxanesuccin Aldehyde compounds such as aldehyde, 2,5-dimethoxytetrahydrofuran and glutaraldehyde and derivatives thereof; divinylsulfone-N, N′-ethylenebis (vinylsulfonylacetamide), 1,3-bis (vinylsulfonyl) -2-propanol, Methylene bi Maleimide, 5-acetyl-1,3-diacryloyl-hexahydro-s-triazine, 1,3,5-triacryloyl-hesahydro-s-triazine, 1,3,5-trivinylsulfonyl-hexahydro-s-triazine, etc. 2,4-dichloro-6-hydroxy-s-triazine sodium salt, 2,4-dichloro-6- (4-sulfoanilino) -s-triazine sodium salt, 2,4-dichloro-6 Active halogen compounds such as (2-sulfoethylamino) -s-triazine and N, N′-bis (2-chloroethylcarbamyl) piperazine; bis (2,3-epoxypropyl) methylpropylammonium · p-toluene Sulfonate, 2,4,6-triethylene-s-triazine, 1,6-hexamethylene , N′-bisethyleneurea and bis-β-ethyleneiminoethylthioether and other ethyleneimine compounds; 1,2-di (methanesulfoneoxy) ethane, 1,4-di (methanesulfoneoxy) butane and 1,5 -Methanesulfonic acid ester compounds such as di (methanesulfoneoxy) pentane; carbodiimide compounds such as dicyclohexylcarbodiimide and 1-dicyclohexyl-3- (3-trimethylaminopropyl) carbodiimide hydrochloride; 2,5-dimethylisoxazole and the like Isoxazole compounds; inorganic compounds such as chromium alum and chromium acetate; N-carboethoxy-2-isopropoxy-1,2-dihydroquinoline and N- (1-morpholinocarboxy) -4-methylpyridinium chloride, etc. A dehydration-condensation type peptide reagent; Active ester compounds such as N, N'-adipoyldioxydisuccinimide and N, N'-terephthaloyldioxydisuccinimide: Isocyanates such as toluene-2,4-diisocyanate and 1,6-hexamethylene diisocyanate And epichlorohydrin-based compounds such as polyamide-polyamine-epichlorohydrin reactants, but are not limited thereto.

  In order to form the surface layer of the present invention, first, the above polymer, epoxy compound, and appropriate additives are added to and mixed with a solvent such as water (including a dispersant and a binder as necessary). Disperse accordingly) to prepare a surface layer coating solution.

The surface layer is formed by a coating method generally well known on the antistatic layer of the present invention, such as dip coating, air knife coating, curtain coating, wire bar coating, gravure coating, and extrusion coating. It can form by apply | coating the said surface layer coating liquid.
The thickness of the surface layer is preferably in the range of 0.01 to 1 μm, and more preferably in the range of 0.01 to 0.2 μm. If it is less than 0.01 μm, the anti-detachment function of the conductive metal oxide particles of the antistatic layer is insufficient, and if it exceeds 1 μm, it is difficult to uniformly apply the coating agent, and uneven coating tends to occur on the product.

  In the present invention, these formed coating layers and hard coat layers contain an antifouling agent, or contain a low surface energy curable resin containing fluorine and / or silicon, and are cured by irradiation with ultraviolet rays. An antifouling coating layer can be obtained by laminating an antifouling layer mainly composed of an adhesive composition.

  The antifouling agent used in the present invention imparts antifouling properties such as water repellency and oil repellency to the coating layer, such as preparation of a coating solution for forming a coating layer and transparent base film Any coating material may be used as long as it has no inconvenience when applied on the surface and exhibits water repellency and oil repellency on the surface of the antifouling coating layer when the antifouling coating layer is formed. Such a resin includes a cured resin containing fluorine and / or silicon.

[Curable resin containing fluorine and / or silicon]
The curable resin containing fluorine and / or silicon contained in the coating layer or antifouling layer used in the present invention includes a known fluorine curable resin, silicon curable resin, or fluorine and silicon-containing part. A curable resin having a block is mentioned, and a curable resin containing a segment having good compatibility with a resin or metal oxide and a segment containing fluorine or silicon is preferable, and the coating layer or the antifouling layer is obtained. By adding, fluorine or silicon can be unevenly distributed on the surface.

Specific examples of these curable resins include block copolymers or graft copolymers of fluorine- or silicon-containing monomers and other hydrophilic or lipophilic monomers.
Examples of the fluorine-containing monomer include perfluoroalkyl group-containing (meth) acrylic acid esters such as hexafluoroisopropyl acrylate, heptadecafluorodecyl acrylate, perfluoroalkylsulfonamidoethyl acrylate, and perfluoroalkylamidoethyl acrylate. It is done.
Examples of the silicon-containing monomer include monomers having a siloxane group by a reaction such as polydimethylsiloxane and (meth) acrylic acid.
Hydrophilic or lipophilic monomers include (meth) acrylic acid esters such as methyl acrylate, hydroxyl-containing polyester and (meth) acrylic acid ester at the terminal, hydroxyethyl (meth) acrylate, polyethylene glycol (meth) acrylic acid Examples include esters.

  Commercially available curable resins include acrylic oligomers having a perfluoroalkyl chain microdomain structure, such as “Defenser MCF-300”, “Defenser MCF-312”, “Defenser MCF-323”, etc. “Megafac F-170”, “Megafac F-173”, “Megafac F-175”, etc. of oligomers containing oily groups, “Megafac F-171”, etc. of oligomers containing perfluoroalkyl groups / hydrophilic groups, etc. ( As described above, Dainippon Ink Chemical Co., Ltd.), and alkyl fluoride-based "Modiper F-200" and "Modiper", which are block monomers of vinyl monomers composed of segments with excellent surface migration and resin-compatible segments F-220 "," Modiper F-600 "," Modiper F-820 ", etc. "Modiper FS-700" on emissions system, "Modiper FS-710", etc. (manufactured by NOF Corporation) and the like.

  In order to provide an antifouling layer on the coating layer, a curable resin having a low surface energy and containing fluorine atoms is preferred. Specifically, JP-A-57-34526 and JP-A-2-19811 are preferred. Examples thereof include a silicon curable resin containing a fluorinated hydrocarbon group and a fluorinated hydrocarbon group-containing polymer described in JP-A-3-17901.

<Protective film B>
The protective film B used in the present invention is located between the polarizing film and the cell, and preferably has a desired phase difference in order to have a function of an optical compensation in addition to the function as a protective film of the polarizing plate, Any film can be used as long as it is free from harmful effects, and various thermoplastic polymer films that are generally used can be suitably used.
Further, from the viewpoint of durability as a polarizing plate, the moisture permeability of the protective film B is preferably low, and the moisture permeability at 60 ° C. and 95% RH is preferably 400 g / m ² · day or less, preferably 200 g / m ² · It is more preferably day or less, and further preferably 100 g / m ² · day or less.
In addition, from the viewpoint of preventing deterioration of display quality of the liquid crystal display device when used as a protective film for a polarizing plate for a liquid crystal display device, the film of the protective film before and after heat treatment at 90 ° C., 2.7%, 100 hours The dimensional change rate (also referred to as dimensional change rate), which is the ratio of the change in length of the film to the length before processing, should be small, and the dimensional change rate in either the TD or MD direction of the film is 0. 0.02% or less is preferable, 0.015% or less is more preferable, and 0.01% or less is still more preferable.
From the same point of view, the dimensional change rate (also referred to as the dimensional change rate) is the ratio of the amount of change in film length before and after 100 hours of wet heat treatment at 60 ° C. and 90% RH on the protective film to the length before treatment. Is preferably smaller, and the dimensional change rate in either the TD direction or the MD direction of the film is preferably 0.3% or less, more preferably 0.2% or less, % Or less is more preferable.
From the same viewpoint, it is preferred towards the photoelastic coefficient is not greater protective film, is preferably ^{10 × 10 -13 cm 2 /dyne(1.0×10 -11} m 2 / N) or less, 7 more preferably × at ¹⁰ -13 ^cm 2 / dyne or less, and more preferably 5 × ¹⁰ -13 ^cm 2 / dyne or less.

<< Thermoplastic polymer film >>
As a material for providing the thermoplastic polymer film used in the present invention, it is preferable that the moisture permeability is low, the dimensional change rate is not large, and the photoelastic coefficient is small, transparency, mechanical strength, thermal stability, moisture A synthetic polymer excellent in properties such as shielding properties is preferred.
Examples of the material for the thermoplastic polymer film include polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, acrylic polymers such as polymethyl methacrylate, and styrene resins such as polystyrene and acrylonitrile / styrene copolymer (AS resin). A polymer, a polycarbonate-type polymer, etc. are mentioned.
In addition, polyethylene, polypropylene, cyclo or polyolefin having a norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfones Polymer, polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, or blend of the above polymers A thing etc. are also mentioned as an example of the polymer which forms the said protective film.
At this time, the protective film is required to have high transparency, a thin film and sufficient strength, and suitable materials in this respect include polycarbonate polymers, norbornene polymers, polyimide polymers, polyester polymers. And the like are preferable. In particular, a protective film made of a norbornene polymer or a polycarbonate polymer is preferable from the viewpoint of cost and retardation.
Furthermore, in a situation where durability is more demanded, norbornene-based polymers, polycarbonate-based polymers, and polyester-based polymers are preferable as polymers having a relatively small dimensional change rate, and norbornene-based polymers are preferable. In addition, a norbornene-based polymer is preferable from the viewpoint that optical distortion with respect to physical distortion with time is small.

[Norbornene resin polymer film]
The thermoplastic saturated norbornene-based resin used in the present invention is a known resin disclosed in, for example, Japanese Patent Laid-Open Nos. 3-14882 and 3-122137. In the present invention, these conventionally known resins are known. A thermoplastic saturated norbornene resin can be suitably used. For example, a ring-opening polymer hydrogenated product of a norbornene monomer, an addition polymer of a norbornene monomer, an addition polymer of a norbornene monomer and an olefin monomer such as ethylene or α-olefin; a norbornene monomer and cyclopentene, cyclo Examples thereof include addition polymers with cyclic olefin monomers such as octene and 5,6-dihydrodicyclopentadiene, and modified products of these resins.

  Examples of the monomer constituting the thermoplastic saturated norbornene resin include, for example, norbornene, 5-methyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene, 5-ethylidene-2-norbornene, 5-methoxycarbonyl-2-norbornene, 5,5-dimethyl-2-norbornene, 5-cyano-2-norbornene, 5-methyl-5-methoxycarbonyl-2-norbornene, 5-phenyl-2-norbornene, 5- Phenyl-5-methyl-2-norbornene, ethylene-tetracyclododecene copolymer, 6-methyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a- Octahydronaphthalene, 6-ethyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahi Lonaphthalene, 6-ethyl-1,4: 5,8-ethylidene-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-chloro-1,4: 5,8-dimethano -1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-cyano-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a -Octahydronaphthalene, 6-pyridyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-methoxycarbonyl-1,4: 5 8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 1,4-dimethano-1,4,4a, 4b, 5,8,8a, 9a-octahydrofluorene, 5,8-methano-1,2,3,4,4a, 5,8,8a-octahydride -2.3-cyclopentadienonaphthalene, 4,9: 5,8-dimethano-3a, 4,4a, 5,8,8a, 9,9a-octahydro-1H-benzoindene, 4,11: 5 10: 6,9-trimethano-3a, 4,4a, 5,5a, 6,9,9a, 10,10a, 11,11a-dodecahydro-1H-cyclopentanthracene and the like.

The norbornene-based monomer may be polymerized by a known method. If necessary, the norbornene-based monomer can be copolymerized with another copolymerizable monomer or hydrogenated to obtain a norbornene-based polymer hydrogenated product.
In addition, polymers and polymer hydrogenated products have α-, β-unsaturated carboxylic acid and derivatives thereof, styrene hydrocarbons, olefinic unsaturated bonds, and hydrolyzable groups by known methods. You may modify | denaturate using an organosilicon compound, an unsaturated epoxy monomer, etc.

In the above polymerization, a hydrated salt of Ir, Os, Ru trichloride, MoC ₁₅ , WC ₁₆ , ReCl ₅ , (C ₂ H ₅ ) ₃ Al, (C ₂ H ₅ ) ₃ Al / TiCl ₄ is used as a polymerization medium. , (Π-C ₄ H ₇ ) ₄ Mo / TiCl ₄ , (π-C ₄ H ₇ ) ₄ W / TiCl ₄ , (π-C ₃ H ₅ ) ₃ Cr / WCl _{6 and the} like. .

  Examples of the thermoplastic saturated norbornene-based resin include, for example, trade names “ZEONOR” and “ZEONEX” manufactured by Nippon Zeon Co., Ltd .; trade names “ARTON” manufactured by JSR Corporation; trade names “OPTOREZ” manufactured by Hitachi Chemical Co., Ltd .; The product name “APEL” manufactured by Mitsui Petrochemical Co., Ltd. is marketed as a commercial product.

  When the number average molecular weight of the thermoplastic saturated norbornene resin decreases, moisture resistance decreases and moisture permeability increases. When the number average molecular weight increases, film formability decreases. Therefore, measurement is performed by gel permeation chromatography (GPC) using a toluene solvent. And 25,000-100,000 are preferable and 30,000-80,000 are more preferable.

-Production method-
As the method for producing the thermoplastic saturated norbornene resin film, any known method may be employed, and for example, the film can be formed by a solution casting method, a melt molding method, or the like.

  In order to form a film by the solution casting method, first, for example, a high boiling point solvent such as toluene, xylene, ethylbenzene, chlorobenzene, triethylbenzene, diethylbenzene, isopropylbenzene, or these high boiling point solvents and cyclohexane, benzene, tetrahydrofuran, hexane The above-mentioned thermoplastic saturated norbornene-based resin is preferably dissolved in a mixed solvent with a low boiling point solvent such as octane or the like to obtain a resin solution.

  Next, the obtained resin solution is cast on a heat-resistant film such as polyethylene terephthalate, a steel belt, a metal foil or the like using a bar coater, a doctor knife, a Meir bar, a roll, a T-die, or the like, and dried by heating.

  In order to form a film by the melt molding method, a method using a T die, a melt extrusion method such as an inflation method, a calendar method, a hot press method, an injection molding method, or the like is used.

  The thickness of the thermoplastic saturated norbornene resin film is usually preferably 5 to 100 μm, more preferably 10 to 80 μm. When the thickness of the film is less than 5 μm, not only the strength is lowered, but there is a problem that when the durability test of the polarizing plate is performed, the curl becomes large. On the contrary, when the thickness exceeds 100 μm, not only the transparency is lowered, but also there is a problem that the moisture permeability becomes small and the drying of water as a solvent of the PVA adhesive is delayed.

  In the thermoplastic saturated norbornene-based resin film, an anti-aging agent such as phenol or phosphorus is used in order to improve the heat resistance, ultraviolet resistance, smoothness, etc. of the film within a range not impairing the effects of the present invention; Anti-degradation agents such as phenols; anti-static agents such as amines; lubricants such as esters of aliphatic alcohols and partial esters of polyhydric alcohols; benzophenone UV absorbers, benzotriazole UV absorbers, acrylonitrile UV absorbers UV absorbers such as agents; leveling agents such as fluorine-based nonionic surfactants, special acrylic resin leveling agents, and silicone leveling agents may be added.

[Polycarbonate film]
Next, the polycarbonate polymer as a thermoplastic polymer film preferably used in the present invention is a polyester of carbonic acid and glycol or dihydric phenol, and carbonic acid and 2,2′-bis (4-hydroxyphenyl). The aromatic polycarbonate having propane (commonly known as bisphenol-A) as a structural unit is of course not limited to this, for example, 1,1-bis (4-hydroxyphenyl) -alkylcycloalkane. 1,1-bis (3-substituted-4-hydroxyphenyl) -alkylcycloalkane, 1,1-bis (3,5-substituted-4-hydroxyphenyl) -alkylcycloalkane, 9,9-bis (4 -Hydroxyphenyl) fluorenes selected from the group consisting of at least one dihydric phenol selected from the group consisting of Examples thereof include homo- or copolymerized polycarbonates, mixtures of polycarbonates containing the above dihydric phenol and bisphenol A as monomer components, and copolymeric polycarbonates containing the above dihydric phenol and bisphenol A as monomer components.

  Specific examples of 1,1-bis (4-hydroxyphenyl) -alkylcycloalkane include 1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (4-hydroxyphenyl) ) -3,3-dimethyl-5,5-dimethylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3-dimethyl-5-methylcyclopentane and the like.

  1,1-bis (3-substituted-4-hydroxyphenyl) -alkylcycloalkane includes 1,1-bis (4-hydroxyphenyl) -alkyl substituted with an alkyl group having 1 to 12 carbon atoms or a halogen group. Cycloalkanes such as 1,1-bis (3-methyl-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (3-ethyl-4-hydroxyphenyl) -3,3- Dimethyl-5,5-dimethylcyclohexane, 1,1-bis (3-chloro-4-hydroxyphenyl) -3,3-dimethyl-4-methylcyclohexane, 1,1-bis (3-bromo-4-hydroxyphenyl) ) -3,3-dimethyl-5-methylcyclopentane.

  1,1-bis (3,5-substituted-4-hydroxyphenyl) -alkylcycloalkane includes 1,1-bis (4-hydroxyphenyl) substituted with an alkyl group having 1 to 12 carbon atoms or a halogen group. Alkylcycloalkanes such as 1,1-bis (3-methyl-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (3,5-dichloro-4-hydroxyphenyl)- 3,3-dimethyl-5-methylcyclohexane, 1,1-bis (3-ethyl-5-methyl-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (3,5- Dimethyl-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) -3,3-di Chill -5-methyl cyclopentane, and the like.

  Examples of 9,9-bis (4-hydroxyphenyl) fluorenes include 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene, Examples include 9-bis (3-ethyl-4-hydroxyphenyl) fluorene.

  Furthermore, as other bisphenol components, 2,2′-bis (4-hydroxyphenyl) propane (bisphenol-A), 4,4 ′-(α-methylbenzylidene) bisphenol, bis (4-hydroxyphenyl) methane, 2 , 2′-bis (4-hydroxyphenyl) butane, 3,3′-bis (4-hydroxyphenyl) pentane, 4,4′-bis (4-hydroxyphenyl) hebutane, 4,4′-bis (4- Hydroxyphenyl) 2,5-dimethylhebutane, bis (4-hydroxyphenyl) methylphenylmethane, bis (4-hydroxyphenyl) diphenylmethane, 2,2′-bis (4-hydroxyphenyl) octane, bis (4-hydroxy) Phenyl) octane, bis (4-hydroxyphenyl) 4-10 fluorophenylmethane, 2 , 2′-bis (3-fluoro-4-hydroxyphenyl) propane, bis (3,5-dimethyl-4hydroxyphenyl) methane, 2,2′-bis (3,5-dimethyl-4-hydroxyphenyl) propane, Bis (3,5-dimethyl-4-hydroxyphenyl) phenylethane, bis (3-methyl-4-hydroxyphenyl) diphenylmethane and the like can be mentioned, and these can be used alone or in combination of two or more.

  In addition to the bisphenol component, the polycarbonate contains a polyester carbonate using a small amount of aliphatic or aromatic dicarboxylic acid as a comonomer of the acid component. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, p-xylene glycol, bis (4-hydroxyphenyl) -methane, 1,1′-bis (4-hydroxyphenyl) -ethane, and 1,1′-. Bis (4-hydroxyphenyl) -butane, 2,2′-bis (4-hydroxyphenyl) -butane and the like can be mentioned. Of these, terephthalic acid and isophthalic acid are preferred.

  The polycarbonate used preferably has a viscosity average molecular weight of 2,000 to 100,000, more preferably 5,000 to 70,000, and still more preferably 7,000 to 50,000. It is preferably 0.07 to 2.70, more preferably 0.15 to 1.80, and more preferably 0.20 to 1.30, expressed as a specific viscosity measured at 20 ° C. in a methylene chloride solution having a concentration of 0.7 g / dL. Is more preferable. A film having a viscosity average molecular weight of less than 2,000 is not suitable because the resulting film becomes brittle, and a film having a viscosity average molecular weight of 100,000 or more is not preferable because processability to the film becomes difficult.

The polycarbonate used in the present invention is particularly preferably a polycarbonate comprising a repeating unit represented by the following general formula (A) and a repeating unit represented by the following general formula (B).
In the following general formula (A), R _{1 to} R ₈ are each independently at least one group selected from a hydrogen atom, a halogen atom, and a hydrocarbon group having 1 to 6 carbon atoms.
In the following general formula (B), R _{11 to} R ₁₈ are each independently at least one group selected from a hydrogen atom, a halogen atom, and a hydrocarbon group having 1 to 22 carbon atoms.

Similarly, the general formula (A), X is a compound represented by the following general formula (X), R ₉ and R ₁₀ are each independently a hydrogen atom, a halogen atom or an alkyl group having 1 to 3 carbon atoms is there.

In the general formula (B), Y is represented by the following general formula group (Y), wherein _R 19 _{~R 21, R 23,} and _{R 24} each independently represent a hydrogen atom, 1 to halogen atoms, and carbon atoms 22 is at least one group selected from hydrocarbon groups, R ₂₂ and R ₂₅ are each independently at least one group selected from hydrocarbon groups having 1 to 20 carbon atoms, Ar _{1 to} Ar ₃ Are each independently at least one group selected from aryl groups having 6 to 10 carbon atoms.

In the polycarbonate containing the repeating unit represented by the general formulas (A) and (B), the content of the repeating unit represented by the general formula (A) is based on the total of the repeating units constituting the polycarbonate. It is preferable that it is 10-90 mol%.
In this polycarbonate, when the content of the repeating unit represented by the general formula (A) is less than 10 mol%, the birefringence of the polymer film is increased, so that it is difficult to obtain a film having uniform retardation characteristics. .
On the other hand, if the content of the repeating unit represented by the general formula (A) exceeds 90 mol% of the whole, the film is easily broken and becomes brittle, and is not suitable as a protective film. More effectively, the content of the repeating unit represented by the general formula (A) is 20 to 80 mol%, and more effectively, the content of the repeating unit represented by the general formula (A) is 30 to 70 mol%. Preferably there is. In particular, in applications where the retardation value is required to have larger characteristics as the wavelength is shorter, the content of the repeating unit represented by the general formula (A) is suitably 30 to 55 mol%, and the retardation value is shorter than the wavelength. For applications that require extremely small characteristics, it is suitable that the content of the repeating unit represented by the general formula (A) is 55 to 70 mol%, and characteristics that the retardation value hardly changes regardless of the wavelength are required. 40-60 mol% is suitable for the intended use.

Among these, in particular, a polycarbonate copolymer and / or a blend comprising a repeating unit represented by the following general formula (C) and a repeating unit represented by the following general formula (D) is preferably used, and has heat resistance and dimensional stability. Excellent in properties and transparency.
In the following general formula (C), R _{26 to} R ₂₇ are each independently a hydrogen atom or a methyl group, and preferably a methyl group from the viewpoint of handleability.
In the following general formula (D), R _{28 to} R ₂₉ are each independently a hydrogen atom or a methyl group, and a hydrogen atom is preferable from the viewpoint of economy, film characteristics, and the like.

  In the present invention, the copolymer and / or blend refers to all composition forms such as a copolymer, a blend, a blend of a copolymer, and a blend of a copolymer and a homopolymer.

  Here, the molar ratio can be obtained for the entire polycarbonate bulk constituting the polymer oriented film, for example, by a nuclear magnetic resonance (NMR) apparatus, regardless of the copolymer or blend.

The above copolymer and / or blend can be produced by a known method.
As the polycarbonate, a method by polycondensation of a dihydroxy compound and phosgene, a melt polycondensation method or the like is preferably used. In the case of a blend, a compatible blend is preferable, but even if the blend is not completely compatible, if the refractive index between the components is matched, light scattering between the components can be suppressed and transparency can be improved.

  In the polycarbonate film of the present invention, a polymer modifier such as a heat stabilizer, an antioxidant, an ultraviolet absorber, a light stabilizer, a transparent nucleating agent, a permanent antistatic agent, and a fluorescent brightening agent is simultaneously present in the film. May be.

  The polycarbonate film obtained by the present invention has good transparency, preferably has a haze value of 5% or less and a total light transmittance of 85% or more, but the haze value is intentionally increased. There is also a case.

  The glass transition temperature of the polycarbonate film is preferably 120 to 280 ° C, more preferably 130 to 270 ° C, still more preferably 140 to 260 ° C, particularly preferably 150 to 250 ° C, and most preferably 160 to 240 ° C. If the temperature is less than 120 ° C., the dimensional stability is poor, and if the temperature exceeds 280 ° C., the temperature control in the stretching process becomes very difficult, so that the production becomes difficult.

  The manufacturing method of the polycarbonate film used for the protective film of this invention is not specifically limited, It is possible to use the film produced using the known method. Examples thereof include a melt film forming method, a solution film forming method, a calendar method, and an injection molding method.

  The thickness of the polycarbonate film of the present invention is generally 500 μm or less, preferably 1 to 300 μm or less, and more preferably 5 to 200 μm.

[Polyester resin film]
The polyester resin used for the thermoplastic resin film of the present invention is not particularly limited in structure. Particularly preferred among these is a resin obtained by condensation polymerization using an aromatic dicarboxylic acid and an aliphatic glycol. Another preferred resin is a resin that is polycondensed using an aromatic dicarboxylic acid and an aromatic polyhydric hydroxyl compound.

  Aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, etc., and use these lower alkyl esters (derivatives capable of forming esters such as anhydrides and lower alkyl esters). Can do.

Examples of the aliphatic glycol include ethylene glycol, propylene glycol, butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, diethylene glycol, and p-xylylene glycol.
In addition, examples of the aromatic polyvalent hydroxyl compound include fluorene derivatives.
Of these, polyethylene terephthalate obtained by the reaction of terephthalic acid and ethylene glycol is preferred as the main component.

  Here, the main component being polyethylene terephthalate means that the copolymer contains 80% by mass or more of polyethylene terephthalate when the copolymer of polyethylene terephthalate is 80% by mole or more, or when blended. .

  Examples of the aromatic dicarboxylic acid having a group selected from sulfonic acid and a salt thereof used for incorporating a sulfonic acid group in the polyester used in the present invention include 5-sodium sulfoisophthalic acid and 2-sodium sulfoisophthalic acid. 4-sodium sulfoisophthalic acid, 4-sodium sulfo-2,6-naphthalenedicarboxylic acid or an ester-forming derivative thereof, and a compound obtained by replacing these sodium with other metals (for example, potassium, lithium, etc.) are used.

  Moreover, what introduce | transduced the group chosen from the sulfonic acid and its salt in glycol may be used, but in order to make a polyester contain a sulfonic acid group, as a compound, the said sulfonic acid group or its salt is preferable. The aromatic dicarboxylic acid is used.

  If the aromatic dicarboxylic acid component having these sulfonic acid groups or salts thereof exceeds 10 mol% of the total aromatic dicarboxylic acid used during production, the stretchability may be inferior or the mechanical strength may be inferior. Moreover, if it is less than 1 mol%, sufficient drying property may not be obtained.

  In the polyester used for the protective film of the present invention, other components may be copolymerized or other polymers may be blended as long as the performance is not impaired.

Other aromatic dicarboxylic acids other than those mentioned above or derivatives thereof include aromatic dicarboxylic acids such as 2,7-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid and lower alkyl esters thereof (anhydrous And derivatives capable of forming esters such as lower alkyl esters).
In addition, during production, cycloaliphatic dicarboxylic acids such as cyclopropanedicarboxylic acid, cyclobutanedicarboxylic acid and hexahydroterephthalic acid and derivatives thereof (derivatives capable of forming esters such as anhydrides and lower alkyl esters), adipic acid, and succinic acid , Aliphatic dicarboxylic acids such as oxalic acid, azelaic acid, sebacic acid and dimer acid and derivatives thereof (an ester-forming derivative such as anhydride and lower alkyl ester) are used in an amount of 10 mol% or less of the total dicarboxylic acid. May be.

  Examples of glycols that can be used in the present invention include ethylene glycol and the aforementioned glycols, as well as trimethylene glycol, triethylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, bisphenol A, p, p'-dihydroxy. Examples include phenylsulfone, 1,4-bis (β-hydroxyethoxyphenyl) propane, polyalkylene (eg, ethylene, propylene) glycol, p-phenylenebis (dimethylolcyclohexane), and the like. You may use it in the quantity below mol%.

  The polyester used in the present invention may be one having a terminal hydroxyl group and / or carboxyl group blocked with a monofunctional compound such as benzoic acid, benzoylbenzoic acid, benzyloxybenzoic acid, methoxypolyalkylene glycol, Alternatively, it may be modified so that a substantially linear copolymer can be obtained with a very small amount of a trifunctional or tetrafunctional ester-forming compound such as glycerin or pentaerythritol.

Moreover, the polyester used for this invention can be copolymerized with the compound which has a bisphenol type compound, a naphthalene ring, or a cyclohexane ring for the purpose of improving the heat resistance of a film.
The polyester used in the present invention preferably has a glass transition temperature (Tg) of 80 ° C. or higher, and more preferably 90 ° C. or higher. If it is less than 80 degreeC, the dimensional stability of the obtained film under high temperature and high humidity may be inferior. Tg was determined from the tan δ peak measured by dynamic viscoelasticity.

-Antioxidant-
The polyester used in the present invention may contain an antioxidant. The effect is particularly remarkable when the polyester contains a compound having a polyoxyalkylene group.
There are no particular restrictions on the type of antioxidant to be contained, and various types of antioxidants can be used. For example, antioxidants such as hindered phenol compounds, phosphite compounds, and thioether compounds can be used. Can be mentioned. Among these, an antioxidant of a hindered phenol compound is preferable in terms of transparency. 0.01-2 mass% is preferable with respect to polyester, and, as for content of antioxidant, 0.1-0.5 mass% is more preferable.

  The polyester film of the present invention can be provided with easy slipperiness if necessary. The slipperiness imparting means is not particularly limited, but the external particle addition method for adding inert inorganic particles to the polyester, the internal particle precipitation method for precipitating the catalyst to be added at the time of polyester synthesis, or a surfactant, etc. A method of applying to the surface is common.

-UV absorber-
An ultraviolet absorber may be added to the polyester film of the present invention as necessary to prevent deterioration of the polarizer and the liquid crystal.

  From the viewpoint of excellent ultraviolet ray absorption ability and good liquid crystal display properties, the ultraviolet ray absorber preferably has a transmittance of 0 to 50% at a wavelength of 380 nm of the polyester film to which the ultraviolet ray absorber is added, and 0 to 30%. Is more preferable, 0 to 10% is more preferable, transmittance of 600 nm is preferably 80 to 100%, more preferably 85 to 100%, and still more preferably 90 to 100%.

  The ultraviolet absorber used in the present invention is a low volatility ultraviolet ray having a mass loss% of 10% or less when the temperature is increased at a rate of temperature increase of 10 degrees / minute until reaching a temperature of 300 ° C. under nitrogen gas. An absorbent or ultraviolet absorber containing 0.4% by mass of the ultraviolet absorber and a polyester resin having a water content of 50 ppm or less heated at 300 ° C. for 1 minute, and then molded into a thickness of 1.5 mm b UV absorption showing heat resistance such that the difference between the value (measured by a color difference meter) and the b value of a plate molded to a thickness of 1.5 mm after heating the polyester resin for 8 minutes is 3.0 or less It is preferable to knead at least one kind of UV absorber having both the volatility and the heat resistance.

When using a low volatility UV absorber with a mass loss of 10% or less when heated at a rate of 10 ° C./min until reaching a temperature of 300 ° C. under nitrogen gas, the transparent polyester resin After adding the UV absorber and melt-kneading, the UV absorber is less likely to evaporate from the film immediately after being discharged from the die part, so that the UV absorption ability is prevented from being lowered, or a large amount of the UV absorber. Use of is unnecessary. In addition, if a large amount of UV absorber is volatilized, the UV absorber volatilized (sublimated) in the production line will contaminate the line, and this may also cause adhesion to the support film traveling in the line. In the invention, this can also be avoided.
The weight loss is preferably 5% or less, and more preferably 1% or less. Generally, the weight loss can be suppressed to 5% or less by setting the molecular weight of the ultraviolet absorber to 400 or more.
Examples of the ultraviolet absorber having the above-described characteristics include, in addition to the ultraviolet absorber having the structural formula represented by the general formula (1), benzophenone-based, benzotriazole-based, salicylic acid ester-based, cyanoacrylate-based, benzoxazine-based, and triazine. A coumarin copolymer system, a polymer ultraviolet absorber described in JP-A-6-148430, and a polymer UV absorber described in JP-A-2002-31715 are also used.

In addition, since the ultraviolet absorber exhibiting heat resistance as described above is stable even at a resin temperature (for example, 300 ° C.) when melt-kneaded with a polyester resin and does not thermally decompose, it absorbs ultraviolet rays when used for a polyester resin support. It is possible to suppress the yellowing of the support film and the decrease in the ultraviolet absorption ability based on the decomposition of the agent.
It is also possible to prevent the degradation of the polyester resin (lowering the molecular weight of the polyester resin) caused by the degradation of the ultraviolet absorber.
The difference between the b values is preferably 2.0 or less, and more preferably 1.0 or less.
Examples of the ultraviolet absorber having the above-mentioned characteristics include a benzoxazine-based ultraviolet absorber and the like in addition to the ultraviolet absorber having the structural formula represented by the general formula (1).

Moreover, it becomes possible to exhibit the said effect together by using the ultraviolet absorber which has the said two characteristics together.
Examples of the ultraviolet absorber having such characteristics include a benzoxazine-based ultraviolet absorber and the like in addition to the ultraviolet absorber having the structural formula represented by the general formula (1).
Furthermore, the ultraviolet absorber having volatility and / or heat resistance as described above can be kneaded at the same time when the support is formed into a film, so that a support having ultraviolet absorbing ability can be easily produced.

<< Function as optical compensation film >>
The protective film B made of the thermoplastic polymer film of the present invention is a film that protects at least one surface of a polarizer constituting a polarizing plate, and at the same time, an optical compensation film having retardation characteristics as an optical compensation function It is preferable to function.
The in-plane retardation value (Re value) and thickness direction retardation value (Rth value) as the optical compensation film are represented by the following mathematical formulas (f) and (g), respectively.
Re = (nx−ny) × d (Equation (f))
Rth = ((nx + ny) / 2−nz) × d Expression (g)
In the above formulas (f) and (g), nx, ny, and nz are the three-dimensional refractive indexes of the film, and the refraction in the x-axis direction, the y-axis direction, and the z-axis direction perpendicular to the film, respectively. Rate. D is the thickness (nm) of the film.

That is, nx, ny, and nz are indices that represent the optical anisotropy of the film. In particular, in the case of the film in the present invention, nx: maximum refractive index in the film plane ny: refractive index azimuth azimuth perpendicular to the direction showing the maximum refractive index in the film plane: refractive index in the film normal direction.

Here, in the present invention, when the polymer film is uniaxially stretched, the stretched direction, and when biaxially stretched, the stretched direction increases the degree of orientation, that is, the orientation of the polymer main chain in terms of chemical structure. When the refractive index in the direction is maximum, the optical anisotropy is positive, and when the refractive index in the orientation direction is minimum, the optical anisotropy is negative.
In the present invention, the optical anisotropy of the polymer film is regarded as a refractive index ellipsoid, and this three-dimensional refractive index is obtained by a method for obtaining it by a known refractive index ellipsoid formula.
Since this three-dimensional refractive index is dependent on the wavelength of the light source to be used, it is preferably defined by the wavelength of the light source to be used. In the present invention, the value is 550 nm unless a wavelength is specified.

The thermoplastic polymer film used in the present invention preferably satisfies at least one of the following mathematical formulas (1) and (2), and the R value and K value are appropriately selected depending on the application.
For example, when providing the viewing angle compensation function of the VA liquid crystal, it is preferable to satisfy at least one of the following mathematical formulas (1-1) and (2-1).
Moreover, when providing the viewing angle compensation function of the IPS liquid crystal, it is preferable to satisfy at least one of the following mathematical formulas (1-2) and (2-2).
Moreover, when providing the function of wide viewing angle of the anti-reflection circularly polarizing plate, it is preferable to satisfy at least one of the following mathematical formulas (1-3) and (2-3).
Furthermore, when providing the function of wide viewing angle as a single polarizing plate, it is preferable to satisfy at least one of the following formulas (1-4) and (2-4).

0 ≦ Re ≦ 300 (nm) ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Formula (1)
−150 ≦ Rth ≦ 400 (nm)... Formula (2)
30 ≦ Re ≦ 200 (nm) ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Formula (1-1)
80 ≦ Rth ≦ 300 (nm) ..... Formula (2-1)
50 ≦ Re ≦ 300 (nm) ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Formula (1-2)
−150 ≦ Rth ≦ 150 (nm)... Formula (2-2)
100 ≦ Re ≦ 170 (nm) ........................ (1-3)
−150 ≦ Rth ≦ 90 (nm)... Formula (2-3)
200 <= Re <= 300 (nm) ... Formula (1-3)
−150 ≦ Rth ≦ 150 (nm)... Formula (2-3)

<< Production Method as Optical Compensation Film >>
In many cases, the obtained film is subjected to a stretching treatment or the like in order to give a retardation characteristic according to the purpose.
Examples of stretching methods include a roll uniaxial stretching method using a roll speed difference, a tenter lateral uniaxial stretching method in which a film width direction end is gripped by a pin or a clip, and the gripped portion is expanded in the width direction. Continuous stretching methods such as a tenter oblique uniaxial stretching method using a difference in speed in the film flow direction and / or a traveling distance difference, a special Z-axis stretching method in which tensile stress is applied in the thickness direction, and a special Z-axis stretching method in which in-plane compressive stress is applied. Is mentioned.
Furthermore, the sequential biaxial stretching method that repeats the uniaxial stretching method as described above, the simultaneous biaxial stretching method that spreads the tenter with a speed difference in the film flow direction in the width direction, and multi-stage stretching that repeats such stretching several times. Law.

  Although several examples of the continuous stretching method for obtaining a film giving a phase difference have been given, the stretching method of the polymer film of the present invention is not limited to these, but continuous stretching is preferable from the viewpoint of productivity. In particular, there is no need for continuous stretching.

  As another method of giving a phase difference to the protective film B of the present invention, an optical anisotropic layer may be provided on the film surface. The optically anisotropic layer is not particularly limited. For example, an alignment layer is further formed on a thermoplastic polymer film directly or on an undercoat layer, and a liquid crystal compound is aligned and solidified thereon. Can be formed. Alternatively, the alignment layer alone can be an optically anisotropic layer. The optically anisotropic layer may be provided on either the surface to which the polarizer is adhered or the surface to which the polarizer is not adhered, but is preferably provided on the surface to which the polarizer is not adhered.

[Alignment layer]
The alignment layer is disposed on the thermoplastic polymer film and is used to align the liquid crystal compound in the optical anisotropic layer adjacent to the optical anisotropic layer described later.
Specific materials constituting the alignment layer include, for example, polyimide, polyamideimide, polyamide, polyetherimide, polyetheretherketone, polyetherketone, polyketonesulfide, polyethersulfone, polysulfone, polyphenylenesulfide, polyphenyleneoxide, Examples include, but are not limited to, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyacetal, polycarbonate, polyarylate, acrylic resin, polyvinyl alcohol, polypropylene, polyvinyl pyrrolidone, cellulosic plastics, epoxy resin, and phenol resin.

  Although a known method is used for the alignment treatment, a treatment method widely adopted as a liquid crystal alignment treatment step of LCD such as rubbing treatment can be used, and a known photo-alignment layer can also be used.

[Optically anisotropic layer]
Since the optically anisotropic layer improves the viewing angle characteristics of the liquid crystal display element, the thickness of the optically anisotropic layer varies depending on the birefringence of the liquid crystal compound constituting it and the orientation state of the liquid crystal compound. In general, the film thickness is preferably 0.1 to 10 μm, and more preferably 0.2 to 5 μm.
A plurality of optically anisotropic layers can be provided for one thermoplastic polymer film, but it is preferably one layer from the viewpoint of productivity.

―Liquid crystal compounds―
The liquid crystal compound is not particularly limited as long as it can be aligned, and examples thereof include a discotic compound or a rod-like liquid crystal compound, which may be a mixture of several kinds of liquid crystal compounds, and by treatment using a chemical reaction or a temperature difference, The orientation can be fixed.
In addition, when an optically anisotropic layer is prepared by preparing a solution containing a liquid crystal compound and an organic solvent, applying the solution, and drying the liquid crystal compound, the alignment treatment of the liquid crystal compound is performed at a temperature lower than the liquid crystal transition temperature. It is also possible to do.

  When a solution containing a liquid crystal compound is applied, the solvent can be dried and removed after application to obtain a liquid crystal layer having a uniform film thickness. The liquid crystal layer can fix the alignment of the liquid crystal by the action of heat or light energy, or by a chemical reaction using heat and light energy in combination.

Further, when the liquid crystal compound is a polymer liquid crystal, the alignment of the liquid crystal may not be fixed using the curing reaction by the chemical reaction.
For example, the alignment can be fixed by heat-treating the polymer liquid crystal above the glass transition temperature and allowing it to cool below the glass transition temperature.
When the glass transition temperature of the polymer liquid crystal is higher than the heat resistance temperature of the thermoplastic polymer film, the alignment film is placed on the thermoplastic polymer film, the polymer liquid crystal is applied, and then the glass transition of the polymer liquid crystal. It can be heated and aligned above the point temperature.
In addition, after orientation solidification on another support, it can be transferred to a thermoplastic polymer film using an adhesive to produce an optical anisotropic body.

In order to give the phase difference characteristic according to the purpose, a method of providing a stretching process and an optically anisotropic layer has been described, but these methods may be used in combination.
In particular, when it is desired to have different in-plane retardation and thickness-direction retardation, the optical anisotropic layer may be provided on the thermoplastic polymer film having different retardation wavelength dependence. .
For example, an VA liquid crystal or the like may be provided with an optically anisotropic layer having a characteristic that the retardation is larger as the wavelength is shorter on a thermoplastic polymer film having a characteristic that the retardation is smaller as the wavelength is shorter. Alternatively, when a stretching process with low productivity such as special Z-axis stretching is required, an optical anisotropic layer is provided on the thermoplastic polymer film subjected to a stretching process with high productivity, and the whole is intended. There may be a phase difference characteristic. For example, an IPS liquid crystal, a circularly polarizing plate and the like are provided with an optically anisotropic layer having a negative thickness direction retardation on a uniaxially stretched thermoplastic polymer film having positive optical anisotropy. Alternatively, an optically anisotropic layer having a positive thickness direction retardation is provided on a uniaxially stretched thermoplastic polymer film having negative optical anisotropy. Furthermore, a biaxially stretched thermoplastic polymer film having negative optical anisotropy is provided with a positive uniaxial optical anisotropic layer having an optical axis in the plane, and the entire object is achieved. There may be a phase difference characteristic.

<< Adhesiveness of thermoplastic polymer film >>
The protective film B made of the thermoplastic polymer film is preferably subjected to a surface treatment for the purpose of forming a layer on the film or improving the adhesion to the polarizer.
Examples of the surface treatment include saponification treatment, corona discharge treatment, ultraviolet irradiation treatment, lamination of an easy-adhesion layer, and the like. The contact angle of water droplets on the film surface is preferably 65 ° or less, more preferably 60 ° or less, and 40 ° or less. More preferably, the surface state is as follows.

<< Easily Adhesive Layer >>
In the present invention, it is preferable to form an easy adhesion layer in order to improve adhesion.
The easy-adhesion layer may be anything as long as it forms a layer on the film as a protective film or improves the adhesion to the polarizer, for example, acrylate latex, methacrylic latex, styrene An easy adhesion layer made of latex such as latex, an easy adhesion layer made of a mixture containing a hydrophilic polymer compound and a crosslinkable resin compound, and the like are used.
These easy adhesion layers may be laminated directly on the thermoplastic polymer film, or may be laminated after performing an easy adhesion treatment such as a saponification treatment or a corona discharge treatment.

[Easily adhesive layer made of latex]
In the present invention, it is preferable that an easy-adhesion layer comprising an acrylate latex, a methacrylic acid latex, or a styrene latex is formed on a film support. In addition, this latex has (a) a diolefin monomer, (b) a vinyl monomer, (c) two or more vinyl groups, acryloyl groups, methacryloyl or allyl groups in one or more molecules. (D) obtained by emulsion polymerization in an aqueous medium in the presence of a polymerization chain transfer agent consisting of α-methylstyrene dimer and another polymerization chain transfer agent. Copolymer latex may be used.

(A) Diolein monomer One of the monomers forming the copolymer (a) Diolein monomer can include conjugated dienes such as butadiene, isoprene, chloroprene, etc., and butadiene is preferred. Used. Moreover, it is preferable that it is 10-60 mass% of the whole copolymer, and, as for content of the (a) diolephin monomer in a copolymer, it is more preferable that it is 15-40 mass%.

(B) Vinyl monomer The (b) vinyl monomer, which is the second component of the copolymer used in the present invention, may be any monomer inherent to a vinyl group, but is preferably the following: Styrene, acrylonitrile, methyl methacrylate, vinyl chloride, vinyl acetate and their derivatives, alkyl esters of acrylic acid, acrylamide, methacrylamide, acrolein, methacrolein, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2 -Hydroxyethyl methacrylate, allyl acrylate, allyl methacrylate, N-methylolated acrylamide, N-methylolated methacrylamide, vinyl isocyanate, allyl isocyanate and the like. Moreover, as content of the (b) vinyl monomer in a copolymer, 90-40 mass% of the whole is preferable, and the said vinyl monomer, especially styrene is 70-40 mass% of the whole copolymer. More preferably.

  Examples of the styrene derivatives include methyl styrene, dimethyl styrene, ethyl styrene, diethyl styrene, isopropyl styrene, butyl styrene, hexyl styrene, cyclohexyl styrene, decyl styrene, benzyl styrene, chloromel styrene, trifluoromethyl styrene, and ethoxymethyl. Styrene, acetoxymethylstyrene, methoxystyrene, 4-methoxy-3-methylstyrene, dimethoxystyrene, chlorostyrene, dichlorostyrene, trichlorostyrene, tetrachlorostyrene, pentachlorostyrene, bromostyrene, dibromostyrene, iodostyrene, fluoro Styrene, trifluorostyrene, 2-bromo-4-trifluoromethylstyrene, 4-fluoro-3-trifluoromethylstyrene, Sulfonyl benzoic acid methyl ester and the like.

  Among the acrylic esters, preferred are acrylic ester, glycidyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate.

(C) Monomer having two or more vinyl groups, acryloyl groups, methacryloyl groups, and allyl groups in the molecule. (C) Two monomers in the molecule that are the third component of the copolymer used in the present invention. As a monomer having the above vinyl group, acryloyl group, methacryloyl group, allyl group, divinylbenzene, 1,5-hexadiene-3-yne, hexatriene, divinyl ether, divinyl sulfone, diallyl phthalate, diallyl carbinol, Examples include so-called cross-linking agents that are usually added during polymerization of vinyl monomers such as diethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and trimethylolpropane dimethacrylate.

  (C) The monomer having two or more vinyl groups, acryloyl groups, methacryloyl groups, and allyl groups in the molecule is 0 with respect to the total of (a) diolephine monomer and (b) vinyl monomer. It is preferable that it is 0.01-10 mass%, and it is more preferable that it is 0.1-5 mass%.

(D) α-Methylstyrene Dimer in Polymerization Chain Transfer Agent (d) α-Methylstyrene Dimer in Polymerization Chain Transfer Agent is an isomer such as (i) 2-4-diphenyl-4-methyl-1- There are pentene, (b) 2-4-diphenyl-4-methyl-2-pentene, and (c) 1-1-3-trimethyl-3-phenylindane.
A preferred composition as the α-methylstyrene dimer is (i) component 40% by mass or more, (b) component and / or (c) component 60% by mass or less, more preferably (b) component 50% by mass or more, The component (b) and / or the component (c) is 50% by mass or less, particularly preferably the component (a) is 70% by mass or more, and the component (b) and / or the component (c) is 30% by mass or less. (A) The chain transfer effect is excellent as the composition ratio of the component increases.

  The α-methylstyrene dimer is an impurity such as unreacted α-methylstyrene, α-methylstyrene oligomers other than the components (a), (b), and (c), as long as the object of the present invention is not impaired. An α-methylstyrene polymer may be included. When α-methylstyrene dimer is used, it can be used in an unpurified state after synthesizing α-methylstyrene dimer as long as the purpose is not impaired.

(D) The proportion of α-methylstyrene dimer in the polymerization chain transfer agent is preferably 2 to 100% by mass, more preferably 3 to 100% by mass, and still more preferably 5 to 95% by mass.
If the proportion of this α-methylstyrene dimer is less than 2% by mass, a copolymer latex excellent in adhesive strength and blocking resistance cannot be obtained.
Moreover, the reactivity at the time of superposition | polymerization can be improved by combined use with (alpha) -methylstyrene dimer and another polymerization chain transfer agent.

(D) As for the usage-amount of a polymerization chain transfer agent, 0.3-10 mass parts is preferable per 100 mass parts of monomer mixtures, and 0.5-7 mass parts is more preferable. When the amount of the (d) polymerization chain transfer agent used is less than 0.3 parts by mass, the blocking resistance is inferior. On the other hand, when it exceeds 10 parts by mass, the adhesive strength is undesirably lowered.
In addition, about the usage-amount of (alpha) -methylstyrene dimer, it is preferable to use in the range of 0.1-5 mass parts per 100 mass parts of monomer mixtures.

Next, as the other chain transfer agent used in combination with the α-methylstyrene dimer in the polymerization chain transfer agent (d), a known polymerization chain transfer agent used in general emulsion polymerization can be used.
Specifically, for example, mercaptans such as octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, t-tetradecyl mercaptan; dimethylxanthogen disulfide, diethylxanthogen disulfide, Xanthogen disulfides such as diisopropylxanthogen disulfide; thiuram disulfides such as tetramethylthiuram disulfide, tetraethylthiuram disulfide and tetrabutylthiuram disulfide; halogenated hydrocarbons such as carbon tetrachloride and ethylene bromide; hydrocarbons such as pentaphenylethane Acrolein, methacrolein, allyl alcohol, 2-ethylhexyl thioglycolate, terpinolene α- terpinene, .gamma.-terpinene, and the like dipentene. These may be used alone or in combination of two or more.
Of these, mercaptans, xanthogen disulfides, thiuram disulfides, carbon tetrachloride and the like are preferably used.

The copolymer latex in the present invention can be produced by a conventionally known emulsion polymerization method except that the monomer mixture and the polymerization chain transfer agent are used.
That is, it can be obtained by adding a monomer mixture, a polymerization initiator, an emulsifier, a polymerization chain transfer agent and the like to an aqueous medium such as water and performing emulsion polymerization.

  The copolymer latex is applied as a subbing layer on a polyester film support. The coating thickness is preferably 50 to 1,000 nm, more preferably 50 to 300 nm, and still more preferably 50 to 200 nm.

  In the present invention, when forming an undercoat layer on a polyester film support, it is preferable to use a dichloro-s-triazine-based crosslinking agent in combination with the copolymer latex. The combined use of dichloro-s-triazine-based cross-linking agent significantly improves the adhesive strength under normal humidity conditions, high humidity conditions, and low humidity conditions, and no cracks occur under low humidity conditions. The effect which was excellent in property, water resistance, solvent resistance, etc. can be provided.

The dichloro-s-triazine-based crosslinking agent used in the present invention is preferably at least one compound represented by the following general formula (5) and general formula (6). In the following general formula (5), A represents an alkyl group, a cyclic alkyl group, an aryl group, an aralkyl group, a metal, or a hydrogen atom. In the general formula (6), R ¹ and R ² are hydrogen, an alkyl group, a cyclic alkyl group, an aryl group, an aralkyl group, —NHR ³ (R ³ is an alkyl group or an acyl group), R ¹ and R ² may be bonded, and may form a 5- to 6-membered ring containing O, S, and N—R ⁴ (R ⁴ is an alkyl group).

These dichloro-s-triazine crosslinking agents can be added in an amount of 0.1 to 100 parts by mass with respect to the monomer mixture. When the addition amount of the dichloro-s-triazine-based crosslinking agent is less than 0.1 parts by mass, the adhesion is not sufficiently improved, and the crack prevention effect, antistatic property, scratch resistance and water resistance under low humidity conditions are also insufficient. Such effects as solvent resistance tend to be insufficient.
On the other hand, when the added amount of the dichloro-s-triazine-based crosslinking agent exceeds 100 parts by mass, a large amount of unreacted crosslinking agent remains and moves to the upper gelatin layer to become a hardened film and adheres to the emulsion or back layer. This is not preferable because the properties are lowered.

Specific examples of these dichloro-s-triazine-based crosslinking agents include the following.

[Hydrophilic polymer compound]
In the present invention, a second undercoat layer containing a hydrophilic polymer compound as a main binder can be further laminated on the undercoat layer to provide an easy adhesion layer.

  Here, as the hydrophilic polymer compound, generally, a polymer compound having a hydrophilic group such as a hydroxyl group may be used, and acylated gelatin such as gelatin, phthalated gelatin, maleated gelatin, methyl cellulose, carboxymethyl cellulose, Cellulose derivatives such as hydroxyethyl cellulose, grafted gelatin obtained by grafting acrylic acid, methacrylic acid or amide onto gelatin, polyvinyl alcohol derivatives (for example, polyvinyl alcohol, vinyl acetate-vinyl alcohol copolymer, polyvinyl acetate, polyvinyl acetal, Polyvinyl homar, polyvinyl benzal, etc.), natural polymer compounds (eg, gelatin, casein, gum arabic, agar, starch, etc.), hydrophilic polyester derivatives (eg, partially sulfonated) Poly (N-vinylpyrrolidone, copoly-vinylpyrrolidone-vinyl acetate, polyacrylamide, polyvinylimidazole, polyvinylpyrazole, etc.), polyhydroxyalkyl acrylate, grafted starch, agarose, albumin, sodium alginate Polysaccharide polyacrylamide, N-substituted acrylamide, N-substituted methacrylamide or the like alone or a copolymer, or a partial hydrolyzate thereof, or a synthetic or natural hydrophilic polymer compound is used. These are used alone or in combination. A preferred hydrophilic polymer is gelatin or a derivative thereof.

  The undercoat layer coating solution used in the present invention is a generally well-known coating method, such as dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, or U.S. Pat. It can apply | coat by the extrusion method etc. which use the hopper as described in 2681294 specification.

  As a thickness of an easily bonding layer, the range of 0.05-1.0 micrometer is preferable. If it is thinner than 0.05 μm, it is difficult to obtain sufficient adhesiveness, and if it is thicker than 1.0 μm, the adhesive effect is saturated.

An ultraviolet absorber can be added to the easy-adhesion layer and the layer containing a hydrophilic polymer as necessary.
From the viewpoint of excellent UV absorption and good liquid crystal display properties, the UV absorber has a transmittance of 0 to 50% at a wavelength of 380 nm over the entire protective film after the UV absorber is added to each layer. Preferably, 0 to 30% is more preferable, 0 to 10% is more preferable, the transmittance at 600 nm is preferably 80 to 100%, 85 to 100% is more preferable, and 90 to 100% is more preferably used. .

[Adhesive layer comprising a mixture containing a hydrophilic polymer compound and a crosslinkable resin compound]
In the protective film of the present invention, a layer obtained by usually heat-treating a mixture containing a hydrophilic polymer compound and a crosslinkable resin compound on at least one surface of the thermoplastic polymer film may be laminated as an easily adhesive layer. Good.
Specifically, these are mainly a mixture containing the hydrophilic polymer compound and the crosslinkable resin compound (hereinafter sometimes referred to as a coating solution) applied on at least one surface of the thermoplastic polymer film, Subsequently, it can obtain by heat-processing. In particular, from the viewpoint of productivity and safety, the mixture containing the hydrophilic polymer compound and the crosslinkable resin compound is usually a solution containing water and preferably an aqueous solution.

-Hydrophilic polymer compounds-
Examples of the hydrophilic polymer compound in the present invention include the aforementioned hydrophilic polymer compounds, and these may be used alone or in combination of two or more. As the hydrophilic polymer compound, a polyvinyl alcohol derivative (for example, polyvinyl alcohol) having a composition similar to that of a polarizer is preferable.
When polyvinyl alcohol is used, the degree of polymerization is preferably 100 to 7,000, more preferably 300 to 5,000, still more preferably 500 to 5,000, and 1,000 to 4,000 is particularly preferred.
The saponification degree is preferably 40 to 99.9%, more preferably 50 to 99.5%, further preferably 60 to 99, and particularly preferably 70 to 95%. preferable.

-Crosslinkable resin compound-
The crosslinkable resin compound in the present invention refers to a raw material monomer that gives a resin that is cured through a crosslinking reaction or the like by external excitation energy or a polymer polymerized therefrom, but is actinic radiation curing that is cured by irradiation with actinic radiation such as ultraviolet rays or electron beams. Thermally crosslinkable resins that initiate a crosslinking reaction with resin and heat may be mentioned, but any of them may be used.

Typical examples of the actinic radiation curable resin include an ultraviolet curable resin. Examples thereof include an ultraviolet curable polyester acrylate resin, an ultraviolet curable acrylic urethane resin, an ultraviolet curable methacrylate ester resin, and an ultraviolet curable resin. Examples thereof include a curable polyester acrylate resin and an ultraviolet curable polyol acrylate resin.
In particular, UV curable polyol acrylate resins are preferred, such as trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, alkyl-modified diester. Photopolymerizable monomer oligomers such as pentaerythritol pentaerythritol are preferred. These polyol acrylate resins have high crosslinkability, high hardness, small cure shrinkage, low odor, low toxicity, and relatively high safety.

  Examples of electron beam curable resins are preferably those having an acrylate-based functional group, such as relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins. , Polybutadiene resin, polythiol polyene resin and the like.

  Examples of thermosetting resins include acrylic resins, styrene resins, epoxy resins, phenoxy resins, phenoxy ether resins, phenoxy ester resins, melamine resins, phenol resins, urethane resins, and also copolymers and mixtures thereof. Good.

  The crosslinkable resin compound is particularly preferably a compound capable of reacting with a hydroxyl group and / or a carboxyl group of a phenolic skeleton, and particularly preferably having an oxazoline group, a diimide group, a hydrazide group, an epoxy group, or the like. Of these, it is particularly preferable to have an oxazoline group. If it has such a group, the main chain structure is not particularly limited, and acrylic, styrene, urethane and the like are preferably used, but not limited thereto.

When the layer composed of the crosslinkable resin compound and the hydrophilic polymer compound is formed as an easy-adhesion layer, the hydrophilic polymer compound in the coating solution is 0.1 to 100 parts by mass of the coating solution. The amount is preferably 25 parts by mass, more preferably 0.3 to 20 parts by mass, still more preferably 0.5 to 15 parts by mass, and particularly preferably 1 to 10 parts by mass.
The crosslinkable resin compound is preferably 0.5 to 30 parts by mass, more preferably 1 to 25 parts by mass, and 1.5 to 20 parts by mass with respect to 100 parts by mass of the coating liquid. More preferably, it is 2 to 15 parts by mass.

  Depending on the desired purpose of the coating liquid, for example, water-soluble polymers other than those described above, surfactants, antifoaming agents, and the like can be appropriately mixed. In preparing a coating solution containing these, it is desirable to prepare respective aqueous solutions whose concentrations are appropriately adjusted, and then mix them to prepare a coating solution. When preparing each aqueous solution, it may be dissolved by heating in order to enhance the solubility.

  For the coating of the coating liquid, a commonly used coating method can be used, for example, spin coating method, Mayer bar coating method, forward rotation roll coating method, gravure roll coating method, reverse Examples of the method include, but are not limited to, a roll coating method.

The coating solution is applied on at least one surface of the thermoplastic polymer film, and then usually heat-treated. In the thermoplastic polymer film production process, the coating solution is further applied after film formation or after film formation and stretching. Work and heat treatment are preferable from the viewpoint of productivity. Furthermore, it is preferable in terms of production energy cost to apply a coating solution to the formed thermoplastic polymer film and then to perform a stretching treatment when the heat treatment is performed.
As thickness of a layer, 0.01-10 micrometers is preferable and 0.05-5 micrometers is more preferable.

When producing a polarizing plate using the protective film of the present invention as at least one of the surface protective films of two polarizing films, the protective film is formed on the transparent base film on the side opposite to the coating layer. It is preferable to improve the adhesion on the adhesive surface by hydrophilizing the surface, that is, the surface to be bonded to the polarizing film.
The hydrophilized surface is effective for improving the adhesiveness with the adhesive layer mainly composed of polyvinyl alcohol. As the hydrophilic treatment, the following saponification treatment is preferably performed. Also, when the saponification treatment is performed as the pretreatment before forming the coating layer in the present invention, the following method is preferably used.

[Saponification]
(1) Method of immersing in alkaline solution A method of saponifying all surfaces that are reactive with alkali on the entire surface of the film by immersing a protective film in an alkaline solution under appropriate conditions. Since it is not necessary, it is preferable in terms of cost.
The alkaline liquid is preferably a sodium hydroxide aqueous solution. The concentration is preferably 0.5 to 3 mol / L, and more preferably 1 to 2 mol / L. Moreover, as a liquid temperature of an alkaline liquid, 30-75 degreeC is preferable and 40-60 degreeC is more preferable.
The combination of the saponification conditions is preferably a combination of relatively mild conditions, but can be set according to the material and configuration of the light scattering film and the antireflection film, and the target contact angle.
After being immersed in the alkaline solution, it is preferable to sufficiently wash with water or neutralize the alkaline component by immersing in a dilute acid so that the alkaline component does not remain in the film.

By saponification treatment, the surface opposite to the surface having the antiglare layer or antireflection layer of the transparent support is hydrophilized.
The protective film is used by adhering the hydrophilic surface of the transparent support to the polarizing film.
The hydrophilized surface is effective for improving the adhesiveness with the adhesive layer mainly composed of polyvinyl alcohol.
In the saponification treatment, the lower the contact angle with water on the surface of the transparent support opposite to the side having the antiglare layer or the low refractive index layer, the better from the viewpoint of adhesiveness to the polarizing film. At the same time, since it is damaged by alkali from the surface having the antiglare layer and the low refractive index layer to the inside, it is important to set the reaction conditions to the minimum necessary.
When the contact angle to water of the transparent support on the opposite surface is used as an index of damage to each layer due to alkali, 10 to 50 degrees is preferable, particularly if the transparent support is triacetylcellulose, and 30 to 50 The degree is more preferable, and 40 to 50 degrees is more preferable. If it is 50 degrees or more, a problem arises in the adhesion to the polarizing film, which is not preferable. On the other hand, if it is less than 10 degrees, the damage is too great, and physical strength is impaired.

(2) Method of applying alkaline solution As a means for avoiding damage to each film in the above-mentioned immersion method, the alkaline solution is applied only to the surface opposite to the surface having the antiglare layer or the low refractive index layer under appropriate conditions. An alkaline solution coating method of coating, heating, washing with water and drying is preferably used.
The application in this case means that an alkaline solution or the like is brought into contact only with the surface to be saponified, and in addition to the application, it may be carried out by spraying or contacting a belt containing the solution. Including.
By adopting these methods, a separate facility and process for applying an alkaline solution are required, which is inferior to the immersion method (1) from the viewpoint of cost.
On the other hand, since the alkali solution contacts only the surface to be saponified, the opposite surface can have a layer using a material that is weak against the alkali solution.
For example, vapor deposition films and sol-gel films have various effects such as corrosion, dissolution, and peeling due to alkali solution, so it is not desirable to use the immersion method. Is possible.

In any of the saponification methods (1) and (2), since each layer can be formed after being unwound from a roll-shaped support, a series of processes are added in addition to the above-described antiglare and antireflection film production process. You may carry out by operation of.
Furthermore, the polarizing plate can be produced more efficiently than the same operation with a single wafer by continuously performing the bonding process with the polarizing plate made of the unwound support.

(3) Method of protecting and saponifying an antiglare layer and an antireflection layer with a laminate film When the antiglare layer and / or the low refractive index layer is insufficient in resistance to an alkaline solution as in the above (2) Then, after forming the final layer, the laminate film is bonded to the surface on which the final layer is formed and then immersed in an alkaline solution to hydrophilize only the side of the triacetyl cellulose opposite to the surface on which the final layer has been formed. After being laminated, the laminate film can be peeled off.
Even in this method, only the surface opposite to the surface on which the final layer of the triacetylcellulose film is formed can be subjected to the hydrophilic treatment necessary for the protective film without damaging the antiglare layer and the low refractive index layer. . Compared with the method (2), there is an advantage that a laminate film is generated as waste, but a device for applying a special alkaline solution is unnecessary.

(4) Method of immersing in alkaline solution after forming up to antiglare layer Up to antiglare layer is resistant to alkaline solution, but when low refractive index layer is insufficiently resistant to alkaline solution, after forming up to antiglare layer It is also possible to soak both surfaces in an alkali solution to hydrophilize both surfaces, and then form a low refractive index layer on the antiglare layer.
Although the manufacturing process becomes complicated, there is an advantage that the interlayer adhesion between the antiglare layer and the low refractive index layer is improved particularly when the low refractive index layer has a hydrophilic group such as a fluorine-containing sol-gel film.

(5) Method of forming a coating on a previously saponified triacetyl cellulose film Saponification is performed by immersing a triacetyl cellulose film in an alkaline solution in advance, and a coating layer is formed directly on one side or via another layer. May be formed. In the case of saponification by dipping in an alkaline solution, interlayer adhesion between the coating layer and the triacetyl cellulose surface hydrophilized by saponification may deteriorate.
In such a case, after saponification, only the surface on which the coating layer is to be formed is treated by corona discharge, glow discharge, etc. to remove the hydrophilic surface and then form an antiglare layer or other layer. I can deal with it. Moreover, when an anti-glare layer or another layer has a hydrophilic group, interlayer adhesion may be good.

(Liquid crystal display device)
Below, the polarizing plate using the protective film of this invention and the liquid crystal display device using this polarizing plate are demonstrated.
The film and polarizing plate of the present invention can be advantageously used for an image display device such as a liquid crystal display device, and is preferably used for the outermost layer of the display.
The liquid crystal display device has a liquid crystal cell and two polarizing plates arranged on both sides thereof, and the liquid crystal cell carries a liquid crystal between two electrode substrates.
Furthermore, one optically anisotropic layer may be disposed between the liquid crystal cell and one polarizing plate, or two optically anisotropic layers may be disposed between the liquid crystal cell and both polarizing plates.

  The liquid crystal cell is preferably in TN mode, VA mode, OCB mode, IPS mode or ECB mode.

<TN mode>
In a TN mode liquid crystal cell, rod-like liquid crystal molecules are substantially horizontally aligned when no voltage is applied, and are twisted and aligned at 60 to 120 °.
TN mode liquid crystal cells are particularly frequently used as color TFT liquid crystal display devices, and are described in many documents.

<VA mode>
In a VA mode liquid crystal cell, rod-like liquid crystal molecules are aligned substantially vertically when no voltage is applied.
The VA mode liquid crystal cell includes (1) a narrowly defined VA mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied, and substantially horizontally when a voltage is applied (Japanese Patent Laid-Open No. Hei 2-). 176625) (2) Liquid crystal cell (SID97, Digest of Tech. Papers (Proceedings) 28 (1997) 845 in which the VA mode is converted into a multi-domain (for MVA mode) in order to enlarge the viewing angle. ), (3) A liquid crystal cell in a mode (n-ASM mode) in which rod-like liquid crystalline molecules are substantially vertically aligned when no voltage is applied and twisted multi-domain alignment is applied when a voltage is applied (Preliminary collections 58-59 of the Japan Liquid Crystal Society) (1998)) and (4) SURVAVAL mode liquid crystal cells (announced at LCD International 98).

<OCB mode>
The OCB mode liquid crystal cell is a bend alignment mode liquid crystal cell in which rod-like liquid crystal molecules are aligned in substantially opposite directions (symmetrically) at the upper and lower portions of the liquid crystal cell. US Pat. No. 4,583,825, No. 5,410,422. Since the rod-like liquid crystal molecules are symmetrically aligned at the upper and lower portions of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. Therefore, this liquid crystal mode is called an OCB (Optically Compensatory Bend) liquid crystal mode. The bend alignment mode liquid crystal display device has an advantage of high response speed.

<IPS mode>
The IPS mode liquid crystal cell is a type in which a nematic liquid crystal is switched by applying a lateral electric field. IDRC (Asia Display '95), p. 577-580 and p. 707-710.

<ECB mode>
In the ECB mode liquid crystal cell, rod-like liquid crystalline molecules are substantially horizontally aligned when no voltage is applied. The ECB mode is one of the liquid crystal display modes having the simplest structure, and is described in detail in, for example, Japanese Patent Application Laid-Open No. 5-203946.

<Brightness enhancement film>
As the brightness enhancement film, a polarization conversion element having a function of separating light emitted from a light source (backlight) into transmitted polarized light, reflected polarized light, or scattered polarized light is used. Such a brightness enhancement film can improve the emission efficiency of linearly polarized light by using retroreflected light from a reflected polarized light or scattered polarized light backlight.
An example is an anisotropic reflective polarizer. An anisotropic reflective polarizer includes an anisotropic multiple thin film that transmits linearly polarized light in one vibration direction and reflects linearly polarized light in the other vibration direction.
An example of the anisotropic multiple thin film is DBEF manufactured by 3M (for example, see JP-A-4-268505).
An example of the anisotropic reflective polarizer is a composite of a cholesteric liquid crystal layer and a λ / 4 plate. An example of such a composite is PCF manufactured by Nitto Denko Corporation (see JP-A-11-231130, etc.).
An example of the anisotropic reflective polarizer is a reflective grid polarizer.
As the reflective grid polarizer, a metal grid reflective polarizer (see US Pat. No. 6,288,840, etc.) that finely processes metal to produce reflected polarized light even in the visible light region, and metal fine particles in a polymer matrix. Examples thereof include those stretched by being inserted (see JP-A-8-184701, etc.).

Moreover, an anisotropic scattering polarizer is mentioned. An example of the anisotropic scattering polarizer is DRP manufactured by 3M (see US Pat. No. 5,825,543).
Furthermore, there is a polarizing element that can perform polarization conversion in one pass. For example, an anisotropic diffraction grating may be used (for example, see JP-A-2001-201635) using smectic C ^* .
The polarizing plate of the present invention can be used together with a brightness enhancement film. When a brightness enhancement film is used, it is more preferable that the polarizing plate and the brightness enhancement film are in close contact with each other in order to prevent moisture from entering the polarizing plate and suppress light leakage.
The adhesive for bonding the polarizing plate and the brightness enhancement film is not particularly limited. For example, acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyvinyl ether, vinyl acetate / vinyl chloride copolymer, modified polyolefin, epoxy-based, fluorine-based, natural rubber, synthetic rubber and other rubber-based polymers Can be appropriately selected and used. In particular, those excellent in optical transparency, exhibiting appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties and excellent in weather resistance, heat resistance and the like can be preferably used.

<Touch panel>
The protective film of the present invention can be applied to touch panels described in JP-A-5-127822 and JP-A-2002-48913.

<Organic EL device>
The protective film of the present invention can be used as a substrate (base film) such as an organic EL element or a protective film.
When the protective film of the present invention is used for an organic EL device or the like, JP-A-11-335661, JP-A-11-335368, JP-A-2001-192651, JP-A-2001-192652, JP-A-2001-192653. JP, 2001-335776, JP, 2001-247859, JP, 2001-181616, JP, 2001-181617, JP, 2002-181816, JP, 2002-181617, JP, 2002-056776, etc. The contents described in each publication can be applied. Moreover, it is preferable to use together with the content of each gazette of Unexamined-Japanese-Patent No. 2001-148291, Unexamined-Japanese-Patent No. 2001-221916, and Unexamined-Japanese-Patent No. 2001-231443.

  Hereinafter, the present invention will be described more specifically by way of examples. However, the embodiments of the present invention are not limited to these examples.

(Preparation of protective film A)
<Preparation of protective film A-001>
Using a coater having a throttle die on a triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd., hereinafter sometimes referred to as “TAC”) having a thickness of 80 μm, a coating layer having the following composition One coating solution was coated so that the thickness after drying was 2.4 μm. It apply | coated on conditions with a conveyance speed of 30 m / min, and after drying for 30 seconds at 60 degreeC, it dried for 5 minutes at 100 degreeC, and produced protective film A-001.

[Coating layer 1 coating solution composition]
-Chlorine-containing polymer: R204
{"Saran Resin R204" manufactured by Asahi Kasei Life & Living Co., Ltd.} 12g
・ Tetrahydrofuran 58g
・ Toluene 5g

[Measurement of moisture permeability]
About obtained protective film A-001, moisture permeability was computed according to JISZ-0208 except having changed humidity control conditions into 60 degreeC and 95% RH.
At this time, the operation of taking out the cup placed in the thermo-hygrostat at an appropriate time interval and weighing it is repeated, and the mass increase per unit time is obtained for each of the two consecutive weighings, and it is constant within 5%. Evaluation continued until.
Moreover, in order to exclude the influence by the moisture absorption etc. of a sample, the blank cup which does not put a hygroscopic agent was measured, and the value of moisture permeability was correct | amended.
Moreover, when measuring the moisture permeability of the protective film having a resin layer containing a vinyl alcohol polymer, set the sample in such an orientation that the resin layer provided on the transparent substrate film is in contact with the measuring cup, The moisture permeability from the transparent base film side was measured by the same method as described above. Thus, when the water vapor transmission rate of protective film A-001 was measured, it was 98 g / m < ² > * day. The results are shown in Table 2.

[Measurement of equilibrium moisture content]
A section (7 mm × 35 mm) of the obtained protective film A-001 was allowed to stand for 24 hours or more in an atmosphere adjusted to 25 ° C. and 80% RH, and then a moisture measuring device and a sample dryer (CA-03, VA). -05, both manufactured by Mitsubishi Chemical Corporation), the moisture content was determined by the Karl Fischer method, and the equilibrium moisture content of each protective film A at 25 ° C. and 80% RH was calculated from the ratio of the moisture content to the sample mass. The results are shown in Table 2.

<Preparation of protective film A-002>
Using a coater having a throttle die on a triacetylcellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm, the coating layer 2 coating solution is dried to have a thickness of 2.4 μm. It was applied to.
It apply | coated on conditions with a conveyance speed of 30 m / min, and after drying at 60 degreeC for 1 minute, it dried at 100 degreeC for 5 minutes, and produced protective film A-002.
Then, when the water vapor transmission rate of obtained protective film A-002 was measured, it was 180 g / m < ² > * day. Further, the “equilibrium moisture content” of the obtained protective film A-002 was also measured in the same manner as the protective film A-001. The results are shown in Table 2.

[Coating layer 2 coating solution composition]
-Chlorine-containing polymer: F216
{"Saran Resin F216" manufactured by Asahi Kasei Life & Living Co., Ltd.} 12g
・ 33 g of tetrahydrofuran
・ Toluene 30g

<Preparation of protective film A-003>
The side on which the coating layer 3 of triacetylcellulose (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd.) was provided was saponified at 50 ° C. using a 1 mol / L alkaline solution.
Thereafter, using a coater having a throttle die on the saponified surface of the triacetylcellulose film, a coating solution for coating layer 3 having the following composition was applied so that the film thickness after drying was 6 μm.
Then, it apply | coated on conditions with a conveyance speed of 30 m / min, and it dried at 130 degreeC for 5 minute (s), and produced protective film A-003.
Then, when the water vapor transmission rate of obtained protective film A-002 was measured, it was 230 g / m < ² > * day. Further, the “equilibrium moisture content” of the obtained protective film A-002 was also measured in the same manner as the protective film A-001. The results are shown in Table 2.

[Coating layer 3 coating solution composition]
・ Vinyl alcohol polymer HR-3010 (manufactured by Kuraray Co., Ltd.) 5 parts by mass ・ Underwater high pressure dispersed mica ME-100 (solid content ratio 5% by mass) 10 parts by mass
・ 100 parts by weight of water

The inorganic layered compound ME-100 (manufactured by Co-op Chemical) was mixed with water so as to have a desired concentration, and then subjected to high-pressure dispersion treatment at 30 Mpa three times using a high-pressure disperser, and dispersed in water.
HR-3010 was dissolved by stirring with 95 ° C. water for 2 hours. Thereafter, both were mixed to prepare a coating solution for coating layer 3.

<Preparation of protective film A-004>
Using a coater having a throttle die on a triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm, the coating layer 1 coating solution is dried to have a thickness of 3.6 μm. It was applied to.
It apply | coated on conditions with a conveyance speed of 30 m / min, and after drying at 60 degreeC for 1 minute, it dried at 100 degreeC for 5 minutes, and produced protective film A-004.
Then, when the water vapor transmission rate of obtained protective film A-004 was measured, it was 64 g / m < ² > * day. Moreover, the “equilibrium water content” of the obtained protective film A-004 was also measured in the same manner as the protective film A-001. The results are shown in Table 2.

<Preparation of Protective Film A-005 to A-010>
<< Creation of base material layer >>
[Production of Cellulose Acylate Film C-1]
-Preparation of cellulose acylate solution (dope) D-01-
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acylate solution D-01.

[Cellulose acylate solution D-01 composition]
Cellulose triacetate (acetyl substitution degree 2.86) 100.0 parts by mass Triphenyl phosphate (plasticizer 1) 6.0 parts by mass Biphenyl phosphate (plasticizer 2) 3.0 parts by mass Methylene chloride 1 solvent) 402.0 parts by mass
・ Methanol (second solvent) 60.0 parts by mass

-Preparation of matting agent solution-
The following composition was charged into a disperser and stirred to dissolve each component to prepare a matting agent solution DM-01.

[Matting agent solution DM-01 composition]
Silica particles having an average particle diameter of 16 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd. 2.2 parts by mass) Cellulose triacetate (acetyl substitution degree 2.88) 2.0 parts by mass Triphenyl phosphate (plasticizer 1) 0 .2 parts by mass-biphenyl phosphate (plasticizer 2) 0.1 parts by mass-methylene chloride (first solvent) 83.5 parts by mass
・ Methanol (second solvent) 12.0 parts by mass

-Preparation of UV absorber solution DU-01-
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare an ultraviolet absorber solution DU-01.

[UV absorber solution DU-01 composition]
-UV-1 (ultraviolet absorber 1) 3.0 parts by mass-UV-10 (ultraviolet absorber 2) 12.0 parts by mass-Cellulose triacetate (acetyl substitution degree 2.86) 4.4 parts by mass-Triphenylphos Fate (plasticizer 1) 0.4 parts by mass Biphenyl phosphate (plasticizer 2) 0.2 parts by mass Methylene chloride (first solvent) 70.0 parts by mass
・ Methanol (second solvent) 10.0 parts by mass

97.4 parts by mass of cellulose acylate solution D-01, 1.3 parts by mass of matting agent solution DM-01, and 1.3 parts by mass of UV absorber solution DU-01 were mixed after filtration. Cast using a casting machine.
When the residual solvent was 60%, the film was peeled off from the band, and the film was held at 100 ° C. using a clip tenter and held at 130 ° C. for 30 seconds with the width after 5% stretching.
Thereafter, the clip was removed and dried at 130 ° C. for 40 minutes to produce a cellulose acylate film C-1.
The obtained cellulose acylate film C-1 had a residual solvent amount of 0.2% and a film thickness of 80 μm.

[Production of Cellulose Acylate Films C-2 to C-7]
-Preparation of cellulose acylate solution (dope) D-02 to D-06-
Each dope composition having the following composition was added to the pressure-resistant airtight tank together with the matting agent solution DM-02 with stirring, and then heated at 80 ° C. for 3 hours to completely dissolve the dope, and further filtered. Cellulose acylate solutions (dope) D-02 to D-06 were respectively prepared.

[Cellulose acylate solution D-02 composition]
Cellulose acetate (acetyl substitution degree 2.88) 100 parts by mass Triphenylphosphine 9 parts by mass Ethylphthalyl ethyl glycolate 3 parts by mass UV-1 0.4 parts by mass UV-6 0.8 parts by mass UV-8 0.8 parts by mass ・ Methylene chloride 475 parts by mass
・ 50 parts by mass of ethanol

[Composition of cellulose acylate solution D-03]
-Cellulose acetate (acetyl substitution degree 2.88) 100 parts by mass-Triphenylphosphine 11 parts by mass-UV-1 0.8 parts by mass-UV-11 0.8 parts by mass-Methylene chloride 475 parts by mass
-Ethanol 50 mass parts However, UV-11 is 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) -5-chlorobenzotriazole.

[Cellulose acylate solution D-04 composition]
-Cellulose acetate (acetyl substitution degree 2.88) 100 parts by mass-Compound shown in the following structural formula 6 parts by mass-Ethyl phthalyl ethyl glycolate 12 parts by mass-UV-10 0 parts by mass-UV-6 4 parts by mass-UV -8 2 parts by mass, 475 parts by mass of methylene chloride
・ 50 parts by mass of ethanol

[Composition of cellulose acylate solution D-05]
-Cellulose acetate propionate (acetyl substitution degree 1.9, propionyl substitution degree 0.8) 100 parts by mass-Triphenylphosphine 9 parts by mass-Ethylphthalyl ethyl glycolate 3 parts by mass-UV-1 0.4 part by mass・ UV-6 0.8 parts by mass ・ UV-8 0.8 parts by mass ・ Methylene chloride 475 parts by mass
・ 50 parts by mass of ethanol

[Matting agent solution DM-02 composition]
Silica particles having an average particle diameter of 16 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd. 2.2 parts by mass) Cellulose triacetate (acetyl substitution degree 2.88) 2.0 parts by mass Triphenyl phosphate (plasticizer 1) 0 .2 parts by mass-biphenyl phosphate (plasticizer 2) 0.1 parts by mass-methylene chloride (first solvent) 85.5 parts by mass
・ Ethanol (second solvent) 10.0 parts by mass

[Casting casting]
The temperature of the dope mixed with cellulose acylate solution D-02 (98.7 parts by mass) and matting agent solution DM-02 (1.3 parts by mass) was adjusted to 35 ° C., and fed to a die, and then a die slit. And uniformly cast on a metal support composed of an endless stainless steel belt.
The cast part of the endless stainless steel belt was inscribed from the inside with a metal roll circulated with hot water of 35 ° C. from the back side and heated.
After casting, the dope film on the support (which will be referred to as a web after casting on a stainless steel belt) is dried by applying hot air of 44 ° C., and after 90 seconds from casting, the amount of residual solvent is 40% by mass. And dried while being conveyed by a large number of rolls.
The temperature of the endless stainless steel belt at the peeling portion was 10 ° C.
The peeled web was transported through the first drying zone set at 50 ° C. for 1 minute, then held at the entrance of the second drying zone at 80 ° C., gripped by the web with a tenter, and at 90 ° C. in the width direction. The film was stretched 1.07 times.
After stretching, the width is maintained for several seconds, then the width is released, and further conveyed for 20 minutes in a third drying zone set at 125 ° C. to dry the cellulose ester film having a thickness of 80 μm. C-2 was obtained.

  Table 1 below shows the type of cellulose acylate solution used in place of the cellulose acylate solution D-02, the film thickness of the film sample after casting, and the stretching ratio in the width direction when gripping the web edge with a tenter. Except for the values described in (2), casting film formation was carried out in the same manner as in the cellulose film sample C-2 to prepare cellulose film sample film samples C-3 to C-7.

Instead of the TD80-UL used in the production of the protective films A-001 to A-003, as shown in Table 2 below, the above-mentioned protection was performed except that the cellulose acylate films C-1 to C-7 were used. Protective films A-005 to A-011 were produced in the same manner as film A-001. The produced protective films A-005 to A-011 were measured for moisture permeability at 60 ° C. and 95% RH, and equilibrium water content at 25 ° C. and 80% RH. The results are shown in Table 2.
As shown in Table 2, the moisture permeability of the produced protective films A-001 to A-011 is 50 to 300 g / m ² · day, and the equilibrium moisture content is 1.5% by mass or more. there were.

<Preparation of protective film A-101>
<< Preparation of norbornene-based resin film C-101 >>
A pellet of a norbornene polymer (trade name: ZEONOR 1420R, manufactured by Nippon Zeon Co., Ltd., glass transition temperature: 136 ° C., saturated water absorption: less than 0.01%) is heated at 110 ° C. using a hot air dryer in which air is circulated. Dry for hours.
A short shaft having a coat hanger type T-die having a lip width of 650 mm with an average surface roughness Ra = 0.04 μm, on which a leaf disk-shaped polymer filter (filtration accuracy 30 μm) is installed and the tip of the die lip is chrome-plated The pellet was melt-extruded at 260 ° C. using an extruder to produce a norbornene-based resin film C-101 having a thickness of 121 μm and a width of 600 mm as a long base film.
The obtained long base film had an equilibrium water content of 0.01% by mass or less at 25 ° C. and 80% RH, and a moisture permeability of 11 g / m ² · day. The in-plane retardation value (Re) was 2 nm.

<< Adjustment of coating solution for undercoat layer >>
Using a mixing tank, the following materials were mixed to prepare an undercoat layer coating solution.

[Coating solution composition for undercoat layer]
・ Styrene butadiene latex (solid content 43%) 300g
・ 2,4-Dichloro-6hydroxy-s-triazine sodium salt (8%) 49 g
・ Distilled water 1,600g

Using a high-frequency transmitter (corona generator HV05-2, manufactured by Tamtec) on one side of the long base film C-101 produced above, the output voltage is 100%, the output is 250 W, and the diameter is 1.2 mm. A corona-treated protective film KA-101 that has been subjected to corona discharge treatment for 3 seconds under the conditions of a wire electrode with an electrode length of 240 mm and a work electrode distance of 1.5 mm and a surface tension of 0.072 N / m. Produced.
Thereafter, the prepared coating solution for undercoat layer was applied so that the dry film thickness was 90 nm. This produced protective film A-101 with an undercoat layer.

<Preparation of protective film A-102>
<< Synthesis of polyethylene terephthalate A >>
Dimethyl terephthalate and ethylene glycol were polymerized in a conventional manner by adding manganese acetate as a transesterification catalyst, antimony trioxide as a polymerization catalyst, and phosphorous acid as a stabilizer to obtain polyethylene terephthalate A.

<< Preparation of polyester film >>
The polyethylene terephthalate A chip material was dried to a water content of 50 ppm or less in a Henschel mixer and a paddle dryer dryer, and then melted in an extruder set at a heater temperature of 280 to 300 ° C. The melted polyester resin was discharged onto a chiller roll electrostatically applied from the die part to obtain an amorphous base.
The amorphous base was stretched in the base flow direction at a stretch ratio of 3.3 times, and then stretched in the base width direction at a stretch ratio of 3.9 times to produce a polyester film having a thickness of 100 μm. Further, the moisture permeability of the produced film was 41 g / m ² · day, and the equilibrium water content at 25 ° C. and 80% RH was 0.4% by mass.

<< Coating of undercoat layer >>
On one side of the produced polyester film, using a high-frequency transmitter (corona generator HV05-2, manufactured by Tamtec) just before coating, a wire electrode with an output voltage of 100%, an output of 250 W, and a diameter of 1.2 mm, A corona discharge treatment was performed for 3 seconds under the conditions of a length of 240 mm and a distance between work electrodes of 1.5 mm to produce KA-102 (corona treatment) having a surface modified so that the surface tension was 0.072 N / m.
Further, the undercoat layer coating solution prepared in the production of the protective film A-101 was applied so that the dry film thickness was 90 nm. This produced protective film A-102 with an undercoat layer.

(Preparation of protective film B)
<Preparation of protective film B-101>
<< Preparation of Norbornene Resin Film C-103 >>
A norbornene-based resin having a film thickness of 110 μm and a width of 600 mm is produced by the same production method as that of the norbornene-based resin film C-101, except that the melt-extruded molten film is stretched 2.1 times in the width direction at 160 ° C. Film C-103 was produced as a long base film.
The obtained norbornene-based resin film C-103 had an equilibrium moisture content of 0.01% by mass or less at 25 ° C. and 80% RH, and a moisture permeability of 11 g / m ² · day. The norbornene resin film C-103 had retardation values of Re = 210 nm and Rth = 110 nm. The results are shown in Table 3.
Further, in the same manner as the protective film A-101, the norbornene-based resin film C-103 is subjected to corona treatment to produce a corona-treated protective film KB-101, and an undercoat layer is applied to the undercoat layer. A protective film B-101 on which was formed.

<Preparation of protective film B-102>
<< Preparation of Norbornene Resin Film C-104 >>
The norbornene-based resin film C-- except that the melt-extruded molten film was subjected to a 1.6-fold stretching process in the conveying direction at 160 ° C. and then a 1.6-fold stretching process in the width direction at 160 ° C. A norbornene-based resin film C-104 having a thickness of 110 μm and a width of 600 mm was produced as a long base film by the same production method as in 101.
The obtained norbornene-based resin film C-104 had an equilibrium water content of 0.01% by mass or less at 25 ° C. and 80% RH. Moreover, the produced norbornene-based resin film C-104 had retardation values of Re = 152 nm and Rth = 11 nm. The results are shown in Table 3.
Further, in the same manner as the protective film KA-101, the norbornene-based resin film C-104 is subjected to corona treatment to produce a corona-treated protective film KB-102, and an undercoat layer is applied to the undercoat layer. A protective film B-102 on which was formed was produced.

<Preparation of protective film B-103>
<< Preparation of Norbornene Resin Film C-102 >>
[Preparation of Norbornene Resin (Polymer P-101)]
8-Methyl-8-methoxycarbonyltetracyclo [4,4,0,12.5,17.10] dodec-3-ene was dissolved in toluene to prepare a 50 mass% concentration solution. The toluene solution 600 cm ^3, were placed in 1.5 dm ³ autoclave was thoroughly purged with pre-ethene.
The solution was saturated with ethene by multiple pressurization with ethene (ethylene) (6 bar). 10 cm ³ of a toluene solution of methylaluminoxane (freezing point depressurization measurement method: a toluene solution of methylaluminoxane having a molecular weight of 1,300 g / mol and having a molecular weight of 1,300 g / mol) was weighed 10 cm ³ , and the mixture was measured at 70 ° C. Stir for 30 minutes.
0.37 mg of isopropylene (1-indenyl) (3-tert-butylcyclopentadienyl) zirconium dichloride was preactivated for 15 minutes in 10 cm ³ of a toluene solution of methylaluminoxane and then added to the reaction vessel. .
The polymerization was carried out for 1 hour with stirring (750 rpm) and the ethene pressure was kept at 6 bar by metering an additional amount.

At the end of the reaction time, the polymerization mixture was discharged into a container, immediately introduced with 5 dm ³ of acetone and stirred for 10 minutes, followed by filtration of the precipitated product.
The filter cake was washed three times alternately with 10% hydrochloric acid and acetone, and the residue was slurried in acetone and filtered again.
The polymer purified in this way was dried at 80 ° C. under reduced pressure (0.2 bar) for 15 hours.
As a result, 40 g of colorless polymer P-101 was obtained. This polymer had a glass transition temperature of 142 ° C., a viscosity number of 185 mL / g, and a mass average molecular weight of 147,000 g / mol.
<< Preparation of Norbornene Resin Film C-105 >>
The norbornene-based polymer P-101 is dissolved in toluene to 35% by mass, cast onto a polyethylene terephthalate process film, peeled off from the process film at 80 ° C. for 5 minutes, 120 ° C. for 5 minutes, and then the tenter. In the stretching process, the film edge is held with a tenter clip, and dried at 150 ° C. for 3 minutes while stretching the film in the film width direction by 2.2 times, and a long base film C-105 made of a norbornene resin. Was made.
The norbornene resin film C-105 after drying had a thickness of 130 μm.
Moreover, the water vapor transmission rate of the produced film was 260 g / m < ² > * day, and the equilibrium water content in 25 degreeC80% RH was 0.33 mass%.
Moreover, the produced norbornene resin film C-105 had retardation values of Re = 196 nm and Rth = −23 nm. The results are shown in Table 3.
Further, in the same manner as the protective film A-101, the norbornene-based resin film C-105 is subjected to corona treatment to produce a corona-treated protective film KB-103, and an undercoat layer is provided. A protective film B-103 having a film formed thereon was produced.

<Preparation of protective film B-104>
<< Production of phase difference PC >>
A sodium hydroxide aqueous solution and ion-exchanged water were charged into a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser, and each monomer represented by the following general formulas (E) and (F) was added at a molar ratio of 15:85. And a small amount of hydrosulfite was added.
Next, methylene chloride was added thereto, and phosgene was blown in at about 20 ° C. over about 60 minutes.
Further, p-tert-butyphenol was added to emulsify, and then triethylamine was added and stirred at 30 ° C. for about 3 hours to complete the reaction.
After completion of the reaction, the organic phase was separated and methylene chloride was evaporated to obtain a polycarbonate copolymer. The composition ratio of the obtained copolymer was almost equal to the monomer charge ratio. Moreover, the glass transition temperature of this copolymer polycarbonate was 216 ° C.

This copolymer polycarbonate was dissolved in methylene chloride to prepare an 18% by mass dope solution. The dope solution was cast on a steel drum, which was continuously peeled off and dried. The film was stretched at 220 ° C. in the machine direction by 2.3 times.
The film thickness of the obtained film was 115 μm, and the residual solvent amount was 1.3% by mass. The stretched film obtained by this stretching treatment had retardation values of Re = 267 nm and Rth = 15 nm.

On this stretched film, a polyvinyl alcohol resin (Kuraray PVA217, polymerization degree 1700, saponification degree 88%) 5% by mass aqueous solution and oxazoline group-containing water-soluble polymer (Nippon Catalyst WS700) 25% by mass aqueous solution in a mass ratio of 7: 3. The aqueous solution mixed at a ratio was applied as a coating liquid by the Meyer bar coating method and heat-treated at 120 ° C. for 5 minutes to prepare a protective film B-104 having a layer having a thickness of 0.6 μm. The produced protective film B-104 had a moisture permeability of 110 g / m ² · day and an equilibrium water content at 25 ° C. and 80% RH of 0.35% by mass. The results are shown in Table 3.

<Preparation of protective film B-105>
In the production of the protective film B-104, the monomers represented by the above general formulas (E) and (F) are dissolved at a molar ratio of 60:40, and the dope solution is cast on a steel drum, which is continuously added. A protective film having retardation values of Re = 157 nm and Rth = −22 nm was obtained in the same manner except that the stretching treatment after peeling off and drying was performed at 220 ° C. in the longitudinal direction at a magnification of 1.8 times. B-105 was produced. The results are shown in Table 3.

<Preparation of protective film B-106>
In the production of the protective film B-104, the monomers represented by the above general formulas (E) and (F) are dissolved at a molar ratio of 35:65, and the dope solution is cast on a steel drum, which is continuously added. The protective film B having a retardation value of Re = 152 nm and Rth = 40 nm was obtained by the same method except that the stretching process after peeling off and drying was performed at 220 ° C. by 1.7 times in the longitudinal direction. -106 was produced. The results are shown in Table 3.

<Preparation of protective film B-107>
Polyethylene terephthalate A was obtained in the same manner as the synthesis of polyethylene terephthalate A in the production of the protective film A-102 described above.

<< Preparation of polyester film >>
The polyethylene terephthalate A chip material was dried to a water content of 50 ppm or less in a Henschel mixer and a paddle dryer dryer, and then melted in an extruder set at a heater temperature of 280 to 300 ° C.
The melted polyester resin was discharged onto a chiller roll electrostatically applied from the die part to obtain an amorphous base. The amorphous base was stretched in the base flow direction at a stretch ratio of 2.0 times, and then stretched in the base width direction at a stretch ratio of 2.0 times to produce a polyester film having a thickness of 100 μm. Further, the moisture permeability of the film produced is ^{41g / m 2 · day, 25} ℃ water content at 80% RH is 0.4 mass%, the retardation value was Re = 1nm, Rth = 45nm. The results are shown in Table 3.

<< Coating of undercoat layer >>
On one side of the produced polyester film, using a high-frequency transmitter (corona generator HV05-2, manufactured by Tamtec) just before coating, a wire electrode with an output voltage of 100%, an output of 250 W, and a diameter of 1.2 mm, A corona discharge treatment was performed for 3 seconds under the conditions of a length of 240 mm and a distance between work electrodes of 1.5 mm to produce KA-102 (corona treatment) having a surface modified so that the surface tension was 0.072 N / m.
Further, the undercoat layer coating solution prepared in the production of the protective film A-101 was applied so that the dry film thickness was 90 nm. This produced protective film B-107 with an undercoat layer.

  About protective film B-101-107 produced above, the moisture permeability, the equilibrium moisture content, the dimensional change rate, and the photoelastic coefficient were measured similarly to protective film A. The results are shown in Table 3.

[Measurement of dimensional change rate]
In the obtained protective film A-001 section (35 mm x 120 mm), two points are plotted in the TD direction or MD direction so as to be 100 mm apart, and the humidity is adjusted for 24 hours or more at 25 ° C and 60% RH. Then, wet heat treatment is performed at 90 ° C. for 2.7% RH (dry) for 100 hours and 60 ° C. for 90 hours at 90% RH. From the length between the plots immediately after the heat treatment and the distance between the two points before the wet heat treatment. The amount of change was determined, and the dimensional change rate was determined from the ratio to the length before wet heat treatment. The results are shown in Table 3.

[Measurement of photoelastic coefficient]
A tensile stress was applied to the MD direction or the TD direction of the section (12 mm × 120 mm) of the obtained protective film A-001, and the retardation at that time was measured with an ellipsometer (M150, JASCO Corporation). The photoelastic coefficient was calculated from the amount of change in retardation with respect to stress. The results are shown in Table 3.

(Example 1)
<Preparation of polarizing plate 001>
<< Preparation of polarizer >>
A polyvinyl alcohol film having a thickness of 100 μm and an average polymerization degree of 2,400 was stretched 2.5 times in the transport direction while being immersed in pure water at 30 ° C. for 1 minute.
Next, the film was stretched 1.2 times in the conveying direction while immersed in a dyeing bath containing iodine and potassium iodide at 30 ° C. for 1 minute.
Next, the film was stretched twice while immersed in a 4% by mass boric acid bath at 60 ° C. for 2 minutes, and further immersed in a 5% by mass potassium iodide concentration 5% by mass bath for 5 seconds, and then at 35 ° C. for 5 minutes. It dried and produced the polarizer.

<< Saponification treatment of protective film >>
The surface of the protective film A-001 was hydrophilized on one surface of the polarizer prepared above, and saponification was performed for the purpose of imparting bonding properties with the polarizer. That is, the obtained protective film A-01 was immersed in a 1.5 mol / L sodium hydroxide aqueous solution at 55 ° C. for 2 minutes, and then neutralized, washed with water, and dried to carry out a saponification treatment.
The protective films A-002 to A-011 and a commercially available triacetyl cellulose film (TAC-TD80UL, manufactured by Fuji Photo Film) were similarly subjected to saponification treatment.
The contact angle of water was measured on the surface of the protective film A-001 subjected to the saponification treatment and the surface on which the coating layer of the protective film A-002 to A-011 was not laminated. Met.

<< Preparation of PVA paste aqueous solution >>
A commercially available 5% aqueous solution of completely saponified polyvinyl alcohol was dissolved at 95 ° C., and the insoluble matter was filtered off and adjusted to obtain a PVA paste aqueous solution.

The protective film A-001 was used as the protective film A on one side of the produced polarizer, the PVA glue aqueous solution was applied to the side on which the coating layer was not laminated, and bonded to the polarizer.
Furthermore, the protective film B-101 is used as the protective film B on the other surface of the polarizer, the PVA aqueous solution is applied to the side on which the undercoat layer is formed and the polarizer, and the other surface of the polarizer is Pasted together. After bonding, the polarizing plate 001 was produced by drying at 70 ° C. for 15 minutes.

(Examples 2-9, 11-12, and 16-18)
<Production of Polarizing Plates 002 to 009, 011 to 012, and 016 to 018>
Further, the polarizing plates 002 to 009, 011 to 012 of the present invention were made in the same manner as the polarizing plate 001 except that the combination of the protective film of the present invention and the drying time after bonding were set to the conditions shown in Table 4. And 016 to 018 were produced.

(Example 13)
<Preparation of Polarizing Plate 013>
<< Preparation of primer solution >>
Hydrogenated product of maleic anhydride-modified styrene / butadiene / styrene block copolymer (melt index value is 200 g, 1.0 g / 10 min at 5 kg load, styrene block content is 30% by mass, hydrogenation rate is 80% or more, anhydrous 2 parts by weight of maleic acid added 2%) was dissolved in a mixed solvent of 8 parts by weight of xylene and 40 parts by weight of methyl isobutyl ketone and filtered through a polytetrafluoroethylene filter having a pore size of 1 μm to obtain a primer solution. .
The protective film A-001 was used as the protective film A on one side of the produced polarizer, the PVA glue aqueous solution was applied to the side on which the coating layer was not laminated, and bonded to the polarizer.
Further, the protective film KB-103 was used as the protective film B on the other surface of the polarizer, and the primer solution was applied to the corona-treated surface, and then bonded to the other surface of the polarizer. After bonding, the polarizing plate 013 was produced by drying at 70 ° C. for 20 minutes.

(Examples 10 and 14 to 15)
<Preparation of polarizing plate 010 and 014 to 015>
Further, polarizing plates 010 and 014 to 015 were produced in the same manner as the polarizing plate 005 except that the combination of the protective film of the present invention and the drying time after bonding were set to the conditions shown in Table 4.

(Comparative Examples 1-2, Comparative Examples 4-14)
<Preparation of Polarizing Plates 101-102, 104-106, 121, 201-206, and 221>
Further, except that the combination of the protective film of the present invention and the drying time after bonding are the conditions shown in Table 4, the polarizing plates 101 to 102, 104 to 106 of the present invention are produced in the same manner as the polarizing plate 001. 121, 201-206, and 221 were produced.

(Comparative Example 3)
<Preparation of Polarizing Plate 103>
Using the protective film KA-102 as the protective film A on one side of the produced polarizer, the primer solution was applied to the surface subjected to corona treatment, and bonded to the polarizer.
Further, the protective film KB-103 was used as the protective film B on the other surface of the polarizer, and the primer solution was applied to the corona-treated surface, and then bonded to the other surface of the polarizer. After bonding, the polarizing plate 103 was produced by drying at 70 ° C. for 20 minutes.

<Evaluation of polarizing plate>
The polarizing plates 001 to 018, 101 to 106, 121, 201 to 206, and 221 obtained as described above are subjected to an adhesion test and a durability test based on the following evaluation criteria, and before and after the durability test test. The degree of polarization and the presence or absence of peeling were evaluated. Table 5 shows the evaluation results.

<< Adhesiveness >>
About the produced polarizing plates 001-018, 101-106, 121, 201-206, and 221, the adhesiveness test of a protective film and a polarizer was done. That is, the edge part of the produced polarizing plate was loosened beforehand before drying, and the sample for adhesive evaluation with the part which isolate | separated the protective film and the polarizer was produced. Next, the separated protective film was peeled off from the polarizer with both hands, and the adhesion was evaluated.

[Evaluation criteria]
○: Not peeled at all △: Partially peeled by applying a considerable peeling force ×: The whole peeled cleanly by applying a certain amount of peeling force

<< Durability >>
About the produced polarizing plates 001-018, 101-106, 121, 201-206, and 221, the durability test in the state of only a polarizing plate single-piece | unit and the state which bonded the polarizing plate to the glass plate was done.
For the sample to be bonded to the glass plate, the surface of the prepared polarizing plate sample on which the protective film B is bonded is bonded to a glass plate of the same size using an adhesive, and the glass plate bonded polarizing plate sample Was made.
The polarizing plate sample conditioned under normal conditions of 25 ° C. and 60% RH and the glass plate-laminated polarizing plate sample were subjected to heat resistance conditions (dry) of 100 ° C. and 100 hours, or 60 ° C. and 95% RH, 720. Durability tests were conducted under wet heat and heat resistance conditions (wet) for each time, and the change in the degree of polarization of the polarizing plate sample before and after the test and the presence or absence of peeling on the bonded surface were evaluated.

<< degree of polarization >>
About the produced polarizing plates 001 to 018, 101 to 106, 121, 201 to 206, and 221, the degree of polarization before and after the durability test is expressed by the following mathematical formula (3) from the parallel transmittance and the orthogonal transmittance at a wavelength of 550 nm. It was calculated and obtained. And the difference ((DELTA) p) of the calculated polarization degree was evaluated as a parameter | index of a durability test.

[Evaluation criteria for degree of polarization]
○: Decrease in polarization degree is 2.0% or less Δ: Decrease in polarization degree exceeds 2.0%, 5.0% or less ×: Reduction in polarization degree exceeds 5.0%

<< Peel-off >>
The polarizing plates 001 to 018, 101 to 106, 121, 201 to 206, and 221 after the durability treatment were observed and evaluated for the presence or absence of peeling at the interface between the polarizer and the protective film. In addition, in the following evaluation criteria, the width of peeling was set to 2 mm as a range that would not cause a significant problem in display performance when used in a liquid crystal display device.

[Evaluation criteria]
○: No peeling was observed Δ: Peeling of 2 mm or less in width occurred at the sample edge, but there was no problem x: Peeling exceeding 2 mm in width was clearly observed at the sample edge

(Examples 19 to 30)
Further, the produced polarizing plate was incorporated into a liquid crystal display device, and the produced liquid crystal display device was evaluated for display unevenness.
<Production of liquid crystal display device>
The polarizing plate provided in the IPS type liquid crystal display device (Th-26LX300, manufactured by Matsushita Electric Industrial Co., Ltd.) is peeled off from the cell together with the retardation film. Instead, the polarizing plate 001 of the present invention is used as the transmission axis of the polarizing plate. Attached to the backlight side (back side) of the cell so as to match the attached polarizing plate, and further, the polarizing plate 004 of the present invention so that the transmission axis of the polarizing plate matches the polarizing plate attached to the product. Affixed to the display surface side (front side) of the cell.
A liquid crystal display device 001 was produced by further incorporating the produced liquid crystal cell into a housing of the liquid crystal display device.
Liquid crystal display devices 002 to 012 were produced by the same method as the liquid crystal display device 001 except that the polarizing plate combined with the liquid crystal cell was replaced with the polarizing plate described in Table 6.

(Examples 31-33)
Also, the polarizing plate provided in the VA type liquid crystal display device (LC-26GD3 manufactured by Sharp) is peeled off from the liquid crystal cell together with the retardation film, and the polarizing plate 002 of the present invention is attached to the product instead of the polarizing plate of the present invention. The liquid crystal cell was attached to the backlight side (back side) of the cell so as to match the polarizing plate, and the polarizing plate 009 of the present invention was further aligned with the polarizing plate attached to the product. Affixed to the display side.
A liquid crystal display device 013 was produced by further incorporating the produced liquid crystal cell into a housing of the liquid crystal display device.
Liquid crystal display devices 014 to 015 were produced by the same method as the liquid crystal display device 013 except that the polarizing plate combined with the liquid crystal cell was replaced with the polarizing plate described in Table 6.

<Display performance evaluation after high temperature and high temperature and high humidity treatment>
<< Contrast evaluation and color evaluation >>
A liquid crystal display device using the produced polarizing plate was prepared by the method described below, and the liquid crystal display device was immediately treated at 100 ° C. (dry) × 120 hours or 60 ° C. and 90% RH for 120 hours, 25 ° C. and 60% RH. The display performance evaluation (contrast evaluation and color evaluation) in the environment was performed and confirmed by the difference with respect to the display performance before wet heat treatment. Table 6 shows the evaluation results.

[Contrast evaluation criteria]
○: Decrease in contrast is less than 5%. Δ: Decrease in contrast is 5% or more and less than 15%. Decrease is not noticeable. ×: Contrast decrease is 15% or more and can be clearly recognized.

<Measurement of color>
About the manufactured liquid crystal display device, the hue u ′ at an angle inclined 60 ° clockwise and 60 ° counterclockwise from the normal direction of the liquid crystal cell in the black display state before and after the durability treatment. v ′ was measured using a luminance meter (BM-5, manufactured by TOPCON) and evaluated based on the following evaluation criteria from the values of the differences Δu ′ and Δv ′ before and after the durability treatment.

[Evaluation criteria for color]
○: Δu ′ and Δv ′ are both 0.05 or less, and the color change of the display image is not known. Δ: Δu ′ or Δv ′ is 0.05 or more, and the color change of the display image is slight. ×: Δu ′ and Δv ′ are both 0.05 or more, and the color change of the display image is large, which is not acceptable.

<< Durability evaluation of display performance >>
Further, the produced polarizing plate was incorporated into a liquid crystal display device, and the durability of the display performance of the produced liquid crystal display device was evaluated.

(Comparative Examples 15-18)
Further, the produced polarizing plate was incorporated into a liquid crystal display device, and the produced liquid crystal display device was evaluated for display unevenness.
<Production of liquid crystal display device>
The polarizing plate provided in the IPS type liquid crystal display device (Th-26LX300, manufactured by Matsushita Electric Industrial Co., Ltd.) is peeled off from the cell together with the retardation film, and the polarizing plate 201 of the present invention is used as the product instead of the polarizing plate of the present invention. Attaching to the backlight side (back side) of the cell so that it matches the attached polarizing plate, and further, the polarizing plate 204 displays the cell so that the transmission axis of the polarizing plate matches the polarizing plate attached to the product. Affixed to the surface side (front side).
A liquid crystal display device 101 was manufactured by further incorporating the manufactured liquid crystal cell into a housing of the liquid crystal display device.
Further, liquid crystal display devices 102 to 104 were produced by the same method as the liquid crystal display device 101 except that the polarizing plate combined with the liquid crystal cell was replaced with the polarizing plate described in Table 6.

(Comparative Examples 19-20)
In addition, the polarizing plate provided in the VA type liquid crystal display device (LC-26GD3 manufactured by Sharp) is peeled off from the liquid crystal cell together with the retardation film, and the polarizing plate 102 of the present invention is attached to the product instead of the polarizing plate 102 of the present invention. The liquid crystal cell was attached to the backlight side (back side) of the cell so as to match the polarizing plate, and the polarizing plate 105 of the present invention was aligned with the polarizing plate attached to the product. Affixed to the display side.
A liquid crystal display device 105 was manufactured by further incorporating the manufactured liquid crystal cell into a housing of the liquid crystal display device.
A liquid crystal display device 106 was produced in the same manner as the liquid crystal display device 105 except that the polarizing plate combined with the liquid crystal cell was replaced with the polarizing plate shown in Table 6.

From the above evaluation results, according to the polarizing plate of the present invention, since the protective film A having a moisture permeability within a predetermined range is provided, light leakage in the liquid crystal display device over time is suppressed, and heat resistance is achieved. It was found that the deterioration of the performance of the polarizing plate in the durability test under the conditions was suppressed.
Moreover, by employ | adopting the polarizing plate which combined the protective film A and the protective film B so that the sum total of the water vapor transmission rate of the protective film A and the water vapor transmission rate of the protective film B may be 100 g / m < ² > * day or more, It was found that a polarizing plate excellent in productivity during polarizing plate processing can be produced.
Moreover, the adhesiveness of a protective film and a polarizer (PVA film) can be ensured by using the polarizing plate which becomes 1.5 mass% or more of the equilibrium moisture content of the protective film A, and heat-and-moisture resistance It was found that the peeling after the durability test under the conditions can be suppressed and the above light leakage can be suppressed.
Furthermore, it was found that the use of the polarizing plate employing the protective film B having a small dimensional change rate or the protective film B having a small photoelastic coefficient is preferable because the deterioration of the image immediately after the aging test becomes smaller.

(Example 34)
<Preparation of protective film A with antireflection layer>
<< Coating of hard coat layer >>
[Preparation of Sol Solution 1]
In a 1,000 mL reaction vessel equipped with a thermometer, a nitrogen inlet tube, and a dropping funnel, 187 g (0.80 mol) of acryloxyoxypropyltrimethoxysilane, 27.2 g (0.20 mol) of methyltrimethoxysilane, 320 g of methanol ( 10 mol) and 0.06 g (0.001 mol) of KF were charged, and 15.1 g (0.86 mol) of water was slowly added dropwise at room temperature with stirring. After completion of the dropwise addition, the mixture was stirred at room temperature for 3 hours, and then heated and stirred for 2 hours under methanol reflux.
Thereafter, low-boiling components were distilled off under reduced pressure, and further filtered to obtain 120 g of sol solution 1. As a result of GPC measurement of the substance thus obtained, the mass average molecular weight was 1,500, and among the components higher than the oligomer component, the component having a molecular weight of 1,000 to 20,000 was 30%. Further, from the measurement result of ^{1 H-NMR,} the structure of the resulting material was a structure represented by the following general formula (7).

Furthermore, the condensation rate α as determined by ²⁹ Si-NMR was 0.56. From this analysis result, it was found that most of the silane coupling agent sol was a linear structure portion.
From the gas chromatography analysis, the raw material acryloxypropyltrimethoxysilane had a residual rate of 5% or less.

<< Preparation of coating solution for hard coat layer >>
A coating solution having the following composition was filtered through a polypropylene filter having a pore size of 30 μm to prepare a coating solution for a hard coat layer.

[Composition of coating liquid for hard coat layer]
・ PET-30 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 40.0g
・ DPHA ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 10.0g
・ Irgacure 184 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 2.0g
-SX-350 (30%) ... 2.0g
・ Cross-linked acrylic-styrene particles (30%) ... 13.0g
・ FP-13 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.06g
・ Sol solution 1 ... 11.0g
・ Toluene ... 38.5g

The compounds used in the hard coat layer coating solution are shown below.
PET-30: A mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (manufactured by Nippon Kayaku Co., Ltd.)
・ Irgacure 184: Polymerization initiator (Ciba Specialty Chemicals Co., Ltd.)
SX-350: average particle size 3.5 μm cross-linked polystyrene particles (refractive index 1.60, manufactured by Soken Chemical Co., Ltd., 30% toluene dispersion, used after dispersion for 20 minutes at 10,000 rpm with a Polytron disperser)
Crosslinked acrylic-styrene particles: average particle size 3.5 μm (refractive index 1.55, manufactured by Soken Chemical Co., Ltd., 30% toluene dispersion, used after dispersion for 20 minutes at 10,000 rpm with a Polytron disperser)

The produced protective film A-001 is unrolled in a roll form, and using a coater having a throttle die, the hard coat layer coating solution is directly extruded onto the surface of the backup roll on which the protective film coating layer is not provided. And applied. After coating at a transfer speed of 30 m / min, drying at 30 ° C. for 15 seconds and 90 ° C. for 20 seconds, and further using a 160 W / cm air-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) under a nitrogen purge. The coating layer is cured by irradiating ultraviolet rays with an irradiation amount of 90 mJ / cm ² to form an anti-glare layer having an anti-glare property having a thickness of 6 μm, and the hard film layer is provided on the protective film A-001. It was.

<Coating of low refractive index layer>
<< Synthesis of Perfluoroolefin Copolymer (1) >>
A 100 mL stainless steel autoclave with a stirrer was charged with 40 mL of ethyl acetate, 14.7 g of hydroxyethyl vinyl ether, and 0.55 g of dilauroyl peroxide, and the system was degassed and replaced with nitrogen gas.
Furthermore, 25 g of hexafluoropropylene (HFP) was introduced into the autoclave and the temperature was raised to 65 ° C. The pressure when the temperature in the autoclave reached 65 ° C. was 0.53 Mpa (5.4 kg / cm ² ).
The reaction was continued for 8 hours while maintaining the temperature, and when the pressure reached 0.31 MPa (3.2 kg / cm ² ), the heating was stopped and the mixture was allowed to cool.
When the internal temperature decreased to room temperature, unreacted monomers were driven out, the autoclave was opened, and the reaction solution was taken out. The obtained reaction solution was poured into a large excess of hexane, and the polymer was precipitated by removing the solvent by decantation.
Further, this polymer was dissolved in a small amount of ethyl acetate and reprecipitated twice from hexane to completely remove the residual monomer. After drying, 28 g of polymer was obtained.
Next, 20 g of the polymer was dissolved in 100 mL of N, N-dimethylacetamide, and 11.4 g of acrylic acid chloride was added dropwise under ice cooling, followed by stirring at room temperature for 10 hours. Ethyl acetate was added to the reaction solution, washed with water, the organic layer was extracted and concentrated, and the resulting polymer was reprecipitated with hexane to obtain 19 g of a perfluoroolefin copolymer (1) represented by the following general formula (8). It was. The resulting polymer had a refractive index of 1.421.

<< Preparation of Sol Solution 2 >>
A stirrer, a reactor equipped with a reflux condenser, 120 parts of methyl ethyl ketone, 100 parts of acryloyloxypropyltrimethoxysilane (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.), 3 parts of diisopropoxyaluminum ethyl acetoacetate were added and mixed. Thereafter, 30 parts of ion-exchanged water was added and reacted at 60 ° C. for 4 hours, and then cooled to room temperature to obtain a sol solution 2.
The mass average molecular weight was 1,600, and among the components higher than the oligomer component, the component having a molecular weight of 1,000 to 20,000 was 100%. Further, from the gas chromatography analysis, the raw material acryloyloxypropyltrimethoxysilane did not remain at all.

<< Preparation of coating solution for low refractive index layer >>
Thermally crosslinkable fluorine-containing polymer having a refractive index of 1.44 containing polysiloxane and hydroxyl group (JTA113, solid content concentration 6%, manufactured by JSR Corporation) 13 g, colloidal silica dispersion MEK-ST-L (trade name, average) Particle size 45 nm, solid content concentration 30%, manufactured by Nissan Chemical Co., Ltd.) 1.3 g, the sol solution 2 0.65 g, methyl ethyl ketone 4.4 g, cyclohexanone 1.2 g were added, and after stirring, the pore size was 1 μm. It filtered with the filter made from a polypropylene, and the low refractive index layer coating liquid 1 was prepared. The refractive index of the layer formed with this coating solution was 1.45.

The protective film A-001 on which the hard coat layer is formed is unwound in a roll form, and using a coater having a throttle die, the coating liquid for the low refractive index layer is applied to the hard coat layer of the protective film on the backup roll. It was directly extruded onto the surface.
After drying at 120 ° C. for 150 seconds and further drying at 140 ° C. for 8 minutes, an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) with 240 W / cm in an atmosphere with an oxygen concentration of 0.1% by nitrogen purge is used. Then, an ultraviolet ray with an irradiation amount of 300 mJ / cm ² is irradiated to form a low refractive index layer having a thickness of 100 nm, wound, and a low refractive index layer is further formed on the protective film A-001 on which the hard coat layer is formed. A protective film A-001 with an antireflection layer was prepared.

  In Example 1, a polarizing plate 301 with an antireflection layer was prepared in the same manner as in Example 1 except that the protective film with antireflection layer A-001 was used instead of the protective film A-001. In the same manner as in No. 1, the degree of polarization after the durability test and evaluation of polarizing plate performance such as peeling were performed. The results are shown in Tables 7-8.

(Examples 35-51 and Comparative Examples 21-34)
Moreover, 35-51 and Comparative Examples 21-34 were carried out similarly to Example 34 except having replaced the protective film A which provides the antireflection layer produced in the said Example 34 with the protective film A shown in Table 7. A polarizing plate with an antireflection layer was prepared, and the degree of polarization after the durability test and evaluation of polarizing plate performance such as peeling were performed in the same manner as in Example 1.
As a result, it was found that in the polarizing plates of Examples 35 to 51, deterioration of the performance of the polarizing plate in the durability test was suppressed. The results are shown in Tables 7-8.

(Examples 52-66 and Comparative Examples 35-40))
In Example 19, except that the polarizing plate shown in Table 9 was used, a liquid crystal display device was produced in the same manner as in Example 19, and as in Example 19, evaluation of durability in the liquid crystal display device form was performed. Carried out.
As a result, it was found that the liquid crystal display devices of Examples 52 to 66 were prevented from being deteriorated in the liquid crystal display device form over time. The results are shown in Table 9.

The polarizing plate of the present invention is excellent in productivity, has a small dimensional change due to heat and humidity, and has high durability, and thus can be suitably used for a liquid crystal display device.
The liquid crystal display device of the present invention is excellent in productivity and has excellent performance in which unevenness due to light leakage is suppressed, and can be suitably used for mobile phones, monitors for personal computers, televisions, liquid crystal projectors, and the like. .

FIG. 1A is a cross-sectional view showing the configuration of the polarizing plate of the present invention. FIG. 1B is a cross-sectional view showing the configuration of the polarizing plate of the present invention. FIG. 2A is a cross-sectional view showing the configuration of the polarizing plate of the present invention. FIG. 2B is a cross-sectional view showing the configuration of the polarizing plate of the present invention. FIG. 2C is a cross-sectional view showing the configuration of the polarizing plate of the present invention. FIG. 2D is a cross-sectional view showing the configuration of the polarizing plate of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material layer of protective film A 2 Cover layer 3 Base material layer of protective film B 4 Optical anisotropic layer 5 Hard coat layer 6 Easy adhesion layer 7 Polarizer (polarizing film)

Claims (13)

It has a polarizer, a protective film A installed on one surface of the polarizer, and a protective film B installed on the other surface of the polarizer, and the protective film A is 60 ° C. and 95% RH. The water vapor permeability at 50 g / m ² · day is 300 g / m ² · day or less, and the protective film B has a water vapor permeability at 60 ° C. and 95% RH of 300 g / m ² · day or less. A polarizing plate. The polarizing plate according to claim 1, wherein the sum of moisture permeability at 60 ° C. and 95% RH of the protective film A and the protective film B is 100 g / m ² · day or more.   The dimensional change rate before and after leaving the protective film B for 100 hours at 60 ° C. and 90% RH is 0.3% or less in at least one of the TD direction and the MD direction of the protective film B. The polarizing plate in any one of.   2. The dimensional change rate before and after leaving the protective film B at 90 ° C. and 2.7% RH for 100 hours is 0.02% or less in at least one of the TD direction and the MD direction of the protective film B. To 4. The polarizing plate according to any one of 3 to 4. The polarizing plate according to claim 1, wherein the protective film B has a photoelastic coefficient of 10 × 10 ⁻¹³ cm ² / dyne or less.   The polarizing plate according to claim 1, wherein the protective film B is made of at least one of a thermoplastic saturated norbornene resin, a polycarbonate resin, and a polyester resin.   The polarizing plate according to any one of claims 1 to 6, wherein the protective film A has an equilibrium water content at 25 ° C and 80% RH of 1.5% or more.   The polarizing plate according to claim 7, wherein the protective film A comprises a base material layer containing cellulose acylate and a coating layer having low moisture permeability.   The polarizing plate according to claim 8, wherein a hard coat layer is formed on the coating layer of the protective film A.   The polarizing plate according to claim 1, wherein the surface of the protective film B on the side to be bonded to the polarizer is subjected to a hydrophilic treatment.   The polarizing plate according to claim 1, which has an adhesive layer or a pressure-sensitive adhesive layer between the protective film B and the polarizer.   The polarizing plate according to claim 1, wherein the polarizer is produced by stretching a film containing at least polyvinyl alcohol. It has a liquid crystal cell and the polarizing plate installed in this liquid crystal cell, and this polarizing plate is a polarizing plate in any one of Claim 1-12, Comprising: The protective film B and a liquid crystal cell oppose. A liquid crystal display device characterized by being installed as described above.