KR20210136993A - Polarizing plate with retardation film and retardation layer - Google Patents

Abstract

Whitening and cracks are suppressed to provide a retardation film excellent in fold resistance. A film containing a predetermined polycarbonate-based resin, Re (450)/Re (550) is 0.98 to 1.03, and Re (550) is 200 nm to 400 nm.

Description

Polarizing plate with retardation film and retardation layer

The present invention relates to a retardation film and a polarizing plate with a retardation layer.

DESCRIPTION OF RELATED ART In recent years, with the spread of a thin display, the image display apparatus (organic electroluminescent display apparatus) in which the organic electroluminescent panel was mounted is proposed. The organic EL panel has a highly reflective metal layer, and problems such as external light reflection and background overlap are likely to occur. Therefore, it is known to prevent these problems by forming a retardation film. However, when the conventional retardation film is used for an image display apparatus, whitening and/or cracking may occur with use, and also the folding resistance may be insufficient.

Japanese Patent No. 3325560 Publication

The present invention has been made in order to solve the above conventional problems, and an object thereof is to provide a retardation film in which whitening and cracking are suppressed and having excellent folding resistance, and a polarizing plate with a retardation layer comprising such retardation film .

Retardation film in embodiment of this invention contains polycarbonate-type resin, Re(450)/Re(550) is 0.98-1.03, Re(550) is 200 nm - 400 nm.

In one embodiment, the said polycarbonate-type resin contains the structural unit derived from the dihydroxy compound represented by following formula (4).

In one embodiment, the polycarbonate-based resin further includes a structural unit derived from an alicyclic dihydroxy compound, the alicyclic dihydroxy compound is represented by the following general formula (II), and R ¹ is It is a structure represented by the following (IIb), and n=0.

HOCH ₂ -R ¹ -CH ₂ OH (II)

In one embodiment, the crack is suppressed in the mold release processability test of the said retardation film.

In one embodiment, whitening and cracking are suppressed in the said retardation film in a sebum resistance test.

In one embodiment, the number of MITs of the retardation film is 500 or more.

In one embodiment, the water vapor transmission rate of the said retardation film is 100 g/m<2>*24h or less.

In one embodiment, the phase difference change after storing for 500 hours on the conditions of the temperature of the said phase difference film 65 degreeC, and 90% of humidity is 1.0 % or less.

According to another aspect of the present invention, a polarizing plate with a retardation layer is provided. This polarizing plate with a retardation layer is provided with a retardation layer and a polarizer, and the said retardation layer is comprised from the said retardation film.

According to one embodiment, the said polarizing plate with a retardation layer is used for the visual recognition side of an image display apparatus.

(Effects of the Invention)

According to the embodiment of the present invention, whitening and cracking are suppressed by using a resin film containing a predetermined polycarbonate-based resin, Re (450) / Re (550) of 0.98 to 1.03, and in-plane retardation of 200 nm to 400 nm Moreover, the retardation film excellent in folding resistance can be implement|achieved.

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of this invention is described, this invention is not limited to these embodiment.

(Definition of terms and symbols)

Definitions of terms and symbols in the present specification are as follows.

(1) refractive index (nx, ny, nz)

"nx" is the refractive index in the direction in which the in-plane refractive index is maximum (that is, the slow axis direction), "ny" is the refractive index in the direction orthogonal to the slow axis in the plane (that is, the fast axis direction), and "nz" is It is the refractive index in the thickness direction.

(2) In-plane phase difference (Re)

"Re(λ)" is an in-plane retardation measured with light having a wavelength of λ nm at 23°C. For example, "Re(550)" is the in-plane retardation measured with the light of wavelength 550nm in 23 degreeC. Re(λ) is obtained by the formula: Re(λ)=(nx-ny)×d when the thickness of the layer (film) is d(nm).

(3) retardation in thickness direction (Rth)

"Rth(λ)" is the phase difference in the thickness direction measured with the light of the wavelength λnm in 23 degreeC. For example, "Rth (550)" is the phase difference in the thickness direction measured with the light of wavelength 550nm in 23 degreeC. Rth(λ) is obtained by the formula: Rth(λ)=(nx-nz)×d when the thickness of the layer (film) is d(nm).

(4) Nz coefficient

The Nz coefficient is obtained by Nz=Rth/Re.

A. Retardation film

The retardation film according to an embodiment of the present invention contains a polycarbonate resin. The retardation film according to the embodiment of the present invention is typically a stretched film of a polycarbonate resin film.

The retardation film exhibits a flat wavelength dispersion characteristic in which the retardation value hardly changes depending on the wavelength of the measurement light. Re(450)/Re(550) of retardation film is 0.98-1.03, Preferably it is 0.99-1.03, More preferably, it is 1.00-1.03. By using the polycarbonate resin from which Re(450)/Re(550) is obtained, whitening and cracking in the sebum resistance test are suppressed, and a retardation film excellent in releasability and folding resistance can be obtained. Moreover, if it is such a wavelength-dispersion characteristic, in a wide band, the outstanding antireflection characteristic can be implement|achieved.

The retardation film preferably exhibits a relationship of nx>ny≥nz in refractive index characteristics. The in-plane retardation Re(550) of the retardation layer film is 200 nm to 400 nm, preferably 220 nm to 350 nm, and more preferably 250 nm to 300 nm. That is, the retardation film can function as a λ/2 plate. Here, "ny=nz" includes not only the case where ny and nz are completely the same, but also the case where they are substantially the same. Therefore, there may be a case where ny<nz is not impaired in the effect of the present invention.

The retardation film preferably has an Nz coefficient of 0.9 to 1.5, more preferably 0.9 to 1.3. If the Nz coefficient is within such a range, an image display device having excellent reflectance and viewing angle dependence of reflected color can be obtained.

The water vapor transmission rate of the retardation film is preferably 100 g/m 2 ·24 h or less, and more preferably 90 g/m 2 ·24 h or less. The lower limit may be, for example, 1 g/m 2 ·24h. If the water vapor transmission rate of the retardation film is within such a range, the advantage that the change in retardation in a humidified environment can be suppressed can be obtained.

The phase difference change after storage (humidification test) for 500 hours under conditions of a temperature of 65° C. and a humidity of 90% of the retardation film is preferably 1.0% or less, and more preferably 0.9% or less. The lower limit may be, for example, 0.01%. The phase difference change (%) is represented by |(Re ₅₀₀ -Re ₀ )/Re ₀ |×100 (%). Re ₀ is the in-plane retardation (nm) of the retardation film before the start of the test, and Re ₅₀₀ is the in-plane retardation (nm) of the retardation film after the test. If the phase difference change of the retardation film is within this range, the advantage that the color change due to the phase difference becomes small for each location on the image display device and that the occurrence of color unevenness on the display is suppressed can be obtained.

The thickness of the retardation film may be appropriately set so as to function as a λ/2 plate. Thickness becomes like this. Preferably they are 20 micrometers - 80 micrometers, More preferably, they are 30 micrometers - 60 micrometers, More preferably, they are 35 micrometers - 50 micrometers.

The retardation film has an absolute value of the photoelastic coefficient of preferably 2×10 ^-11 m2/N or less, more preferably 2.0×10 ^-13 m2/N to 1.5×10 ^-11 m2/N, more preferably 1.0 ×10 ^-12 m2/N to 1.2×10 ^-11 m2/N. If the absolute value of the photoelastic coefficient is within such a range, a phase difference change is unlikely to occur when a shrinkage stress during heating occurs. As a result, thermal unevenness of the resulting image display apparatus can be prevented favorably.

In the said retardation film, the crack is suppressed in the mold release processability test. That is, the retardation film can be favorably used even in applications requiring a release shape. This advantage can be obtained by including the specific polycarbonate resin described later in the retardation film.

The retardation film has suppressed whitening and cracking in the sebum resistance test. That is, good characteristics can be maintained even when the retardation film is used, for example, on the viewing side of an image display device and continuously contacted with a user. This is to solve the problem recognized for the first time by using the retardation film on the visual recognition side of an image display device for a long period of time, and is an unexpectedly excellent effect. This advantage can be obtained by including the specific polycarbonate resin described later in the retardation film.

In the retardation film, the number of MITs is 500 or more. That is, the retardation film can exhibit excellent folding resistance even when used for a bendable (preferably foldable) image display device. These advantages can be obtained by stretching a resin film including a specific polycarbonate resin to be described later under a specific stretching method and stretching conditions to be described later to form a retardation film.

B. Resin film

As described above, the retardation film is typically a stretched film of a polycarbonate resin film.

(polycarbonate resin)

The polycarbonate resin according to the present invention contains at least a structural unit derived from a dihydroxy compound having a bonding structure represented by the following structural formula (1), and has at least one bonding structure -CH ₂ -O- in the molecule It is produced by reacting a dihydroxy compound containing at least a dihydroxy compound with a diester carbonate in the presence of a polymerization catalyst.

Here, the dihydroxy compound having a bonding structure represented by Structural Formula (1) includes a structure having two alcoholic hydroxyl groups and a linking group -CH ₂ -O- in the molecule, and in the presence of a polymerization catalyst, diester carbonate If it is a compound which can react with and generate|generate a polycarbonate, even if it is a compound of any structure, it is possible to use it, and it does not matter even if it uses multiple types together. Moreover, you may use together the dihydroxy compound which does not have the bonding structure represented by Structural formula (1) as a dihydroxy compound used for the polycarbonate resin by this invention. Hereinafter, the dihydroxy compound having the bonding structure represented by Structural Formula (1) is referred to as the dihydroxy compound (A), and the dihydroxy compound not having the bonding structure represented by the Structural Formula (1) is referred to as the dihydroxy compound (B) It is sometimes abbreviated as

(dihydroxy compound (A))

The "linking group -CH ₂ -O-" in the dihydroxy compound (A) means a structure in which atoms other than a hydrogen atom are bonded to each other to constitute a molecule. In this linking group, as an atom to which at least an oxygen atom can bond or an atom to which a carbon atom and an oxygen atom can bond simultaneously, a carbon atom is most preferable. The number of "linking groups -CH ₂ -O-" in the dihydroxy compound (A) is preferably 1 or more, more preferably 2 to 4.

More specifically, as the dihydroxy compound (A), for example, 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene, 9,9-bis(4-(2-hydroxyl) Ethoxy)-3-methylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isopropylphenyl)fluorene, 9,9-bis(4-(2-hydroxyl) Ethoxy)-3-isobutylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butylphenyl)fluorene, 9,9-bis(4-(2) -Hydroxyethoxy)-3-cyclohexylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene, 9,9-bis(4-( 2-hydroxyethoxy)-3,5-dimethylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butyl-6-methylphenyl)fluorene, 9, A compound having an aromatic group in a side chain as exemplified by 9-bis(4-(3-hydroxy-2,2-dimethylpropoxy)phenyl)fluorene and an ether group bonded to an aromatic group in the main chain, bis[4-( 2-hydroxyethoxy)phenyl]methane, bis[4-(2-hydroxyethoxy)phenyl]diphenylmethane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]ethane, 1 ,1-bis[4-(2-hydroxyethoxy)phenyl]-1-phenylethane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane, 2,2-bis[4 -(2-hydroxyethoxy)-3-methylphenyl]propane, 2,2-bis[3,5-dimethyl-4-(2-hydroxyethoxy)phenyl]propane, 1,1-bis[4- (2-hydroxyethoxy)phenyl]-3,3,5-trimethylcyclohexane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 1,4-bis[4- (2-hydroxyethoxy)phenyl]cyclohexane, 1,3-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 2,2-bis[4-(2-hydroxyethoxy) -3-phenylphenyl]propane, 2,2-bis[(2-hydroxyethoxy)-3-isopropylphenyl]propane, 2,2-bis[3-tert-butyl-4-(2-hydroxy Ethoxy)phenyl]propane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]butane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]-4-methyl pentane , 2,2-bis[4-(2-hydroxyethoxy)phenyl]octane, 1,1-bis[4-(2-hydroxyethoxy) )phenyl]decane, 2,2-bis[3-bromo-4-(2-hydroxyethoxy)phenyl]propane, 2,2-bis[3-cyclohexyl-4-(2-hydroxyethoxy) Bis(hydroxyalkoxyaryl)alkanes as exemplified by )phenyl]propane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 1,1-bis[3-cyclohexyl Bis(hydroxyalkoxyaryl)cycloalkane as exemplified by -4-(2-hydroxyethoxy)phenyl]cyclohexane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclopentane diphenyl ether, as exemplified by 4,4'-bis(2-hydroxyethoxy)diphenyl ether, 4,4'-bis(2-hydroxyethoxy)-3,3'-dimethyldiphenyl ether Hydroxyalkoxydiaryl ethers, 4,4'-bis(2-hydroxyethoxyphenyl)sulfide, 4,4'-bis[4-(2-dihydroxyethoxy)-3-methylphenyl]sulfide Bishydroxyalkoxyarylsulfides as exemplified by feed, 4,4'-bis(2-hydroxyethoxyphenyl)sulfoxide, 4,4'-bis[4-(2-dihydroxyethoxy) Bishydroxyalkoxyarylsulfoxides as exemplified by )-3-methylphenyl]sulfoxide, 4,4'-bis(2-hydroxyethoxyphenyl)sulfone, 4,4'-bis[4-(2) -dihydroxyethoxy)-3-methylphenyl]sulfone, as exemplified by bishydroxyalkoxyarylsulfones, 1,4-bishydroxyethoxybenzene, 1,3-bishydroxyethoxybenzene, 1, 2-bishydroxyethoxybenzene, 1,3-bis[2-[4-(2-hydroxyethoxy)phenyl]propyl]benzene, 1,4-bis[2-[4-(2-hydroxyl Ethoxy)phenyl]propyl]benzene, 4,4'-bis(2-hydroxyethoxy)biphenyl, 1,3-bis[4-(2-hydroxyethoxy)phenyl]-5,7-dimethyl and compounds having a cyclic ether structure such as adamantane, anhydrosugar alcohols represented by dihydroxy compounds represented by the following formula (4), and spiroglycols represented by the following formula (6). It may be used independently and may be used in combination of 2 or more type.

These dihydroxy compounds (A) may be used independently and may be used in combination of 2 or more type. In the present invention, examples of the dihydroxy compound represented by the formula (4) include isosorbide, isomannide, and isoidet in a stereoisomer relationship. A combination of the above may be used.

In addition, isosorbide obtained by dehydration condensation of sorbitol, which is abundantly present as a resource among dihydroxy compounds (A) and is prepared from various readily available starches, is obtained from the viewpoint of ease of acquisition and production, optical properties, and moldability. Most preferred. In the present invention, isosorbide is preferably used as the dihydroxy compound (A).

(dihydroxy compound (B))

In the present invention, as the dihydroxy compound, a dihydroxy compound (B) which is a dihydroxy compound other than the dihydroxy compound (A) may be used. As the dihydroxy compound (B), for example, an alicyclic dihydroxy compound, an aliphatic dihydroxy compound, an oxyalkylene glycol, an aromatic dihydroxy compound, or a diol having a cyclic ether structure is used in the composition of the polycarbonate. It can be used together with a dihydroxy compound (A), for example, the dihydroxy compound represented by Formula (4) as a dihydroxy compound used as a unit.

Although it does not specifically limit as an alicyclic dihydroxy compound which can be used for this invention, Preferably, the compound containing a 5-membered ring structure or a 6-membered ring structure is used normally. In addition, the 6-membered ring structure may be fixed in a chair form or a mold by a covalent bond. When the alicyclic dihydroxy compound has a 5-membered ring or 6-membered ring structure, the heat resistance of the polycarbonate obtained can be made high. The number of carbon atoms contained in the alicyclic dihydroxy compound is usually 70 or less, preferably 50 or less, and more preferably 30 or less. Although heat resistance becomes high, so that this value becomes large, a synthesis|combination becomes difficult, refinement|purification becomes difficult, or cost becomes expensive. It is easy to refine|purify and it becomes easy to obtain, so that a carbon atom number becomes small.

Specific examples of the alicyclic dihydroxy compound having a 5-membered ring structure or a 6-membered ring structure that can be used in the present invention include an alicyclic dihydroxy compound represented by the following general formula (II) or (III).

HOCH ₂ -R ¹ -CH ₂ OH (II)

HO-R ² -OH (III)

(In formulas (II) and (III), R ¹ and R ² each represent a cycloalkylene group having 4 to 20 carbon atoms)

As the cyclohexanedimethanol which is the alicyclic dihydroxy compound represented by the general formula (II), in the general formula (II), R ¹ is the following general formula (IIa) ( ^{wherein R 3} is an alkyl group having 1 to 12 carbon atoms, or represents a hydrogen atom). Specific examples of such substances include 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, and 1,4-cyclohexanedimethanol.

As tricyclodecanedimethanol and pentacyclopentadecanedimethanol which are alicyclic dihydroxy compounds represented by the above general formula (II), R ¹ in the general formula (II) is the following general formula (IIb) (wherein n is represents 0 or 1).

As decalindimethanol or tricyclotetradecanedimethanol which is an alicyclic dihydroxy compound represented by the general formula (II), in the general formula (II), R ¹ is the following general formula (IIc) (wherein m is 0 or 1 is included). Specific examples thereof include 2,6-decalin dimethanol, 1,5-decalin dimethanol, and 2,3-decalin dimethanol.

Moreover, as norbornane dimethanol which is an alicyclic dihydroxy compound represented by the said general formula (II), R<^1> in general formula (II) includes various isomers represented by the following general formula (IId). Specific examples of such substances include 2,3-norbornane dimethanol and 2,5-norbornane dimethanol.

As adamantane dimethanol which is an alicyclic dihydroxy compound represented by General formula (II), R<^1> in General formula (II) includes various isomers represented by the following general formula (IIe). Specific examples of this include 1,3-adamantane dimethanol and the like.

In addition, in the cyclohexanediol which is an alicyclic dihydroxy compound represented by the general formula (III), in the general formula (III), R ² is the following general formula (IIIa) ( ^{wherein R 3} is an alkyl group having 1 to 12 carbon atoms) or hydrogen atom). Specific examples thereof include 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-methyl-1,4-cyclohexanediol, and the like.

As tricyclodecanediol and pentacyclopentadecanediol, which are alicyclic dihydroxy compounds represented by the general formula (III), R ² in the general formula (III) represents the following general formula (IIIb) (wherein n is 0 or 1 is included).

As decalindiol or tricyclotetradecanediol which is an alicyclic dihydroxy compound represented by the general formula (III), in the general formula (III), R ² is the following general formula (IIIc) (wherein m is 0 or 1) It includes various isomers represented by ). As such, 2,6-decalindiol, 1,5-decalindiol, 2,3-decalindiol and the like are specifically used.

As norbornanediol which is an alicyclic dihydroxy compound represented by the said general formula (III), R<^2> in general formula (III) includes various isomers represented by the following general formula (IIId). As such, 2,3-norbornanediol, 2,5-norbornanediol, etc. are specifically used.

As adamantanediol which is an alicyclic dihydroxy compound represented by the said general formula (III), R<^2> in general formula (III) includes various isomers represented by the following general formula (IIIe). As such, 1,3-adamantanediol or the like is specifically used.

Among the specific examples of the above-described alicyclic dihydroxy compound, cyclohexanedimethanols, tricyclodecanedimethanols, adamantanediols, and pentacyclopentadecanedimethanols are preferred, and ease of availability and ease of handling From the viewpoint of that, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, and tricyclodecanedimethanol are preferable. In the present invention, tricyclodecanedimethanol is suitably used as the dihydroxy compound (B).

Examples of the aliphatic dihydroxy compound usable in the present invention include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, and 1,2-butanediol. , 1,5-heptanediol, and 1,6-hexanediol. Examples of the oxyalkylene glycols usable in the present invention include diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol.

As the aromatic dihydroxy compound usable in the present invention, for example, 2,2-bis(4-hydroxyphenyl)propane [=bisphenol A], 2,2-bis(4-hydroxy-3,5- Dimethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-diethylphenyl)propane, 2,2-bis(4-hydroxy-(3,5-diphenyl)phenyl)propane, 2 ,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxyphenyl)pentane, 2,4'-dihydroxy-diphenylmethane, bis( 4-hydroxyphenyl)methane, bis(4-hydroxy-5-nitrophenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 3,3-bis(4-hydroxyphenyl)pentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl)sulfone, 2,4'-dihydroxydiphenylsulfone, bis(4-hydroxyphenyl)sulfide, 4, 4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dichlorodiphenyl ether, 4,4'-dihydroxy-2,5-diethoxydiphenyl ether, 9, 9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy-2-methyl)phenyl]fluorene, 9,9-bis( 4-hydroxyphenyl) fluorene and 9,9-bis (4-hydroxy-2-methylphenyl) fluorene are mentioned.

Examples of the diols having a cyclic ether structure that can be used in the present invention include spiroglycols and dioxane glycols. In addition, the above exemplary compound is an example of an alicyclic dihydroxy compound, an aliphatic dihydroxy compound, an oxyalkylene glycol, an aromatic dihydroxy compound, and a diol having a cyclic ether structure that can be used in the present invention. It is not limited to these. These compounds can be used 1 type, or 2 or more types together with the dihydroxy compound represented by Formula (4).

By using these dihydroxy compounds (B), effects such as improvement of flexibility, improvement of heat resistance, and improvement of moldability according to the use can be obtained. Although the ratio of the dihydroxy compound (A), for example, the dihydroxy compound represented by Formula (4) to all the dihydroxy compounds constituting the polycarbonate resin according to the present invention, is not particularly limited, it is preferably 10 mol% or more, more preferably 40 mol% or more, still more preferably 60 mol% or more, preferably 90 mol% or less, more preferably 80 mol% or less, still more preferably 70 mol% or less. When there are too many content rates of the structural unit derived from another dihydroxy compound, performance, such as an optical characteristic, may fall.

When an alicyclic dihydroxy compound is used among the other dihydroxy compounds, the dihydroxy compound (A) relative to all the dihydroxy compounds constituting the polycarbonate, for example, a dihydroxy compound represented by formula (4) Although the ratio of the total of and alicyclic dihydroxy compound is not specifically limited, Preferably it is 80 mol% or more, More preferably, it is 90 mol% or more, More preferably, it is 95 mol% or more.

Further, in the polycarbonate resin according to the present invention, the dihydroxy compound (A), for example, a structural unit derived from a dihydroxy compound represented by formula (4), and a constitution derived from an alicyclic dihydroxy compound Although the content ratio of the unit can be selected at any ratio, the structural unit derived from the dihydroxy compound represented by formula (4): the structural unit derived from the alicyclic dihydroxy compound = 1:99 to 99:1 ( mol%) is preferable, and in particular, the structural unit derived from the dihydroxy compound represented by the formula (4): the structural unit derived from the alicyclic dihydroxy compound = 10:90 to 90:10 (mol%) desirable. If there are more structural units derived from the dihydroxy compound represented by the formula (4) than the above range and fewer structural units derived from the alicyclic dihydroxy compound, the color is likely to occur, and conversely, the dihydroxy compound represented by the formula (4) is more likely to be colored. When there are few structural units derived from a hydroxy compound and there are many structural units derived from an alicyclic dihydroxy compound, there exists a tendency for molecular weight to become difficult to rise.

In addition, when using an aliphatic dihydroxy compound, oxyalkylene glycol, aromatic dihydroxy compound, or diol having a cyclic ether structure, the dihydroxy compound (A) for all dihydroxy compounds constituting the polycarbonate , For example, the ratio of the sum total of the dihydroxy compound represented by Formula (4) and each dihydroxy compound is not specifically limited, It can select by arbitrary ratios. In addition, the content ratio of the structural unit derived from the dihydroxy compound (A), for example, the dihydroxy compound represented by Formula (4), and the structural unit derived from each of these dihydroxy compounds is not particularly limited, either, It can be selected in any ratio.

The detail of polycarbonate-type resin is described in Unexamined-Japanese-Patent No. 2012-31370, for example. The description of the above patent document is incorporated herein by reference.

C. Manufacturing method of retardation film

The manufacturing method of the retardation film by embodiment of this invention includes the extending|stretching process of a resin film. The resin film is a film formed of the polycarbonate resin described in section B above.

In one embodiment, the retardation film can be produced by biaxial stretching. Simultaneous biaxial stretching may be sufficient as biaxial stretching, and sequential biaxial stretching may be sufficient as it. The draw ratio in the longitudinal direction is preferably more than 1.0 times and 2.0 times or less, and more preferably 1.1 times to 1.5 times. The draw ratio of the width direction becomes like this. Preferably they are 1.6 times - 2.2 times, More preferably, they are 1.8 times - 2.0 times. By stretching the film formed of the polycarbonate resin at such a draw ratio, it is possible to realize not only desired optical properties but also very excellent mechanical properties (eg, releasability and bending resistance).

The stretching temperature of the resin film is preferably Tg-30°C to Tg+30°C, more preferably Tg-15°C to Tg+15°C, still more preferably Tg-10°C to Tg+10°C. . By stretching at such a temperature, a retardation film having suitable properties in the present invention can be obtained. In addition, Tg is the glass transition temperature of the constituent material of a film.

By selecting the stretching method and stretching conditions as described above, and stretching the resin film containing the polycarbonate resin as described above, whitening and cracking in the sebum resistance test are suppressed, and a retardation film excellent in releasability and folding resistance is obtained. can get

D. Polarizing plate with retardation layer

The retardation film according to items A to C may be provided as a laminate with other optical films and/or optical members. In one embodiment, retardation film can be provided as a laminated body with a polarizing plate (polarizing plate with retardation layer). Accordingly, the present invention includes a polarizing plate with a retardation layer having the retardation film. A polarizing plate with a retardation layer according to an embodiment of the present invention includes a polarizing plate and a retardation layer composed of the retardation film. In the retardation film, the angle between the absorption axis of the polarizer of the polarizing plate and the slow axis of the retardation film may be appropriately set according to the purpose and purpose. In one embodiment, the angle is preferably 40° to 50°, more preferably 42° to 48°, and still more preferably about 45°.

A polarizing plate typically has a polarizer and the protective layer arrange|positioned at least on one side of a polarizer.

Any suitable polarizer may be employed as the polarizer. For example, a single-layered resin film may be sufficient as the resin film which forms a polarizer, and the laminated body of two or more layers may be sufficient as it.

As a specific example of a polarizer composed of a single-layer resin film, a polyvinyl alcohol (PVA)-based film, a partially formalized PVA-based film, an ethylene/vinyl acetate copolymer-based partially saponified film, etc. and polyene-based oriented films such as those subjected to dyeing treatment and stretching treatment with a sexual substance, dehydration treatment products of PVA and dehydrochloric acid treatment products of polyvinyl chloride. Preferably, a polarizer obtained by dyeing a PVA-based film with iodine and uniaxially stretching it is used from the viewpoint of excellent optical properties.

Dyeing with the said iodine is performed by immersing a PVA-type film in the iodine aqueous solution, for example. Preferably the draw ratio of the said uniaxial stretching is 3 to 7 times. Extending|stretching may be performed after a dyeing process, and may be performed, dyeing|staining. Moreover, after extending|stretching, you may dye|stain. A swelling process, a crosslinking process, a washing process, a drying process, etc. are given to a PVA-type film as needed. For example, by immersing the PVA-based film in water and washing with water before dyeing, it is possible not only to wash the surface of the PVA-based film from stains and anti-blocking agents, but also to swell the PVA-based film to prevent staining of dyeing and the like.

As a specific example of a polarizer obtained using a laminate, a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate. The polarizer obtained by using is mentioned. The detail of the manufacturing method of such a polarizer is described in Unexamined-Japanese-Patent No. 2012-73580 etc., for example. The description of the above patent document is incorporated herein by reference. The above publication is incorporated herein by reference in its entirety.

In one embodiment, the thickness of a polarizer becomes like this. Preferably they are 1 micrometer - 25 micrometers, More preferably, they are 3 micrometers - 10 micrometers, More preferably, they are 3 micrometers - 8 micrometers. Curl|Karl at the time of a heating can be suppressed favorably as the thickness of a polarizer is such a range, and favorable external appearance durability at the time of a heating is acquired.

The protective layer is formed of any suitable protective film that can be used as a film for protecting the polarizer. Specific examples of the material used as the main component of the protective film include cellulose resins such as triacetyl cellulose (TAC), polyester, polyvinyl alcohol, polycarbonate, polyamide, polyimide, polyethersulfone, and transparent resins such as polysulfone-based, polystyrene-based, polynorbornene-based, polyolefin-based, (meth)acrylic-based and acetate-based resins. Moreover, thermosetting resins, such as (meth)acrylic type, a urethane type, (meth)acryl urethane type, an epoxy type, silicone type, or ultraviolet curable resin etc. are mentioned. In addition to this, for example, glassy polymers, such as a siloxane type polymer, are also mentioned. Moreover, the polymer film described in Unexamined-Japanese-Patent No. 2001-343529 (WO01/37007) can also be used. As a material of this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in a side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain can be used, for example, iso and a resin composition comprising an alternating copolymer composed of butylene and N-methylmaleimide and an acrylonitrile/styrene copolymer. The polymer film may be, for example, an extrusion molding of the resin composition.

The thickness of the protective layer is preferably 10 µm to 100 µm. The protective layer may be laminated on the polarizer via an adhesive layer (specifically, an adhesive layer, an adhesive layer), or may be laminated on the polarizer in close contact (not through an adhesive layer). Surface treatment layers, such as a hard-coat layer, a glare-proof layer, and an antireflection layer, may be formed in the protective layer arrange|positioned on the outermost surface of a polarizing plate with a retardation layer as needed.

The polarizing plate with a retardation layer may be used on the viewing side of an image display device. In addition, the retardation layer in a polarizing plate with a retardation layer may be arrange|positioned at the visual recognition side, and may be arrange|positioned at the display cell side.

(Example)

Hereinafter, the present invention will be specifically described by way of Examples, but the present invention is not limited by these Examples. In addition, the measuring method and evaluation method of each characteristic are as follows.

(1) In-plane retardation and wavelength dispersion characteristics

The retardation film obtained by the Example and the comparative example was cut out to 4 cm in length and 4 cm in width, and it was set as the measurement sample. About the said measurement sample, the in-plane retardation Re (550) was measured using the Axometrics company make and product name "Axoscan". Moreover, Re(450) was also measured, and Re(450)/Re(550) was computed.

(2) moisture permeability

For the retardation films obtained in Examples and Comparative Examples, in accordance with the moisture permeability test (cup method) of JIS Z0208, the amount of water vapor (g) passing through a sample of 1 m2 in area in an atmosphere at a temperature of 40°C and a humidity of 92%RH in 24 hours measured.

(3) Phase difference change

The retardation films obtained in Examples and Comparative Examples were cut out to 5 cm x 5 cm, the adhesive was affixed to one side with a hand roller, and the adhesive side was affixed to the single side|surface of alkali glass, and the test piece was obtained. The test piece was stored in an oven at a temperature of 65°C and a humidity of 90% for 500 hours (humidity test), and the phase difference change (%) before and after the start of the test (%) was calculated.

(4) Mold release processability test

The retardation film obtained in Examples and Comparative Examples _{was irradiated with a CO 2} laser at an energy of 3Kw, cut in the direction perpendicular to the flow direction and flow direction of the film, and a measurement sample of 200 mm × 200 mm was obtained. The cut part was observed using the laser microscope, and when a crack did not generate|occur|produce, it was set as (circle), a crack generate|occur|produced and/or when a cutting was not possible, it was set as X.

(5) Sebum resistance test

The retardation films obtained in Examples and Comparative Examples were cut out to 5 cm x 5 cm, the adhesive was affixed to one side with a hand roller, and the adhesive side was affixed to the single side|surface of alkali glass, and the test piece was obtained. After the obtained test piece was immersed in an oleic acid solution under the conditions of 65 degreeC and 90 %RH for 72 hours and taken out, the transparent thing was made into (circle), and the thing which whitening or cracking was made into x.

(6) Number of MITs

The MIT test was conducted in accordance with JIS P 8115. Specifically, retardation films obtained in Examples and Comparative Examples were cut out to a length of 15 cm and a width of 1.5 cm to obtain a measurement sample. Attach the measurement sample to the MIT anti-fatigue tester BE-202 (manufactured by TESTER SANGYO CO., Ltd.) (load 1.0 kgf, clamp R: 0.38 mm), and bend repeatedly at a test speed of 90 cpm and a bending angle of 90°. It carried out and made the number of times of bending when a measurement sample fracture|ruptures into a test value. The thing of 500 or more times of an experience value was made into (circle), and the thing of less than 500 times was made into x.

[Example 1]

1. Preparation of resin film

47.19 parts by mass of tricyclodecanedimethanol (hereinafter, sometimes abbreviated as "TCDDM") to 81.98 parts by mass of isosorbide (hereinafter, sometimes abbreviated as "ISB"), diphenyl carbonate (hereinafter, " DPC") 175.1 parts by mass and 0.979 parts by mass of a 0.2 mass % cesium carbonate aqueous solution as a catalyst are put into a reaction vessel, and the heating bath temperature is heated to 150° C. as the first step of the reaction in a nitrogen atmosphere. and, if necessary, the raw materials were dissolved while stirring (about 15 minutes). Next, the pressure was set to 13.3 kPa from normal pressure, and the phenol generated while raising the heating bath temperature to 190°C in 1 hour was taken out of the reaction vessel. After maintaining the entire reaction vessel at 190°C for 15 minutes, as the second step, the pressure in the reaction vessel was set to 6.67 kPa, the heating bath temperature was raised to 230°C in 15 minutes, and the generated phenol was taken out of the reaction vessel. . Since the stirring torque of the stirrer increased, the temperature was raised to 250°C in 8 minutes, and the pressure in the reaction vessel was made to reach 0.200 kPa or less in order to remove the generated phenol. After reaching a predetermined stirring torque, the reaction was terminated, and the resulting reactant was pushed into water to obtain polycarbonate resin pellets. After vacuum drying the obtained polycarbonate resin at 80 ° C for 5 hours, a single screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 250 ° C), T-die (width 300 mm, set temperature: 250 ° C), and coating A 135-micrometer-thick polycarbonate resin film was produced using the film film forming apparatus provided with the drag roll (setting temperature: 120-130 degreeC) and the winder.

2. Preparation of retardation film

The unstretched polycarbonate resin film was subjected to preheat treatment and simultaneous biaxial stretching using a simultaneous biaxial stretching machine to obtain a retardation film. The preheating temperature was 138.5°C, the stretching temperature was 138.5°C, and the draw ratio in the longitudinal direction was 1.2 times and the draw ratio in the width direction was 1.9 times. The obtained retardation film had a wavelength dispersion value of 1.025, an in-plane retardation Re(550) of 269 nm, a water vapor transmission rate of 80 g/m 2 ·24h, and a phase difference change of 0.8%. The obtained retardation film was used for evaluation of said (4)-(6). A result is shown in Table 1.

[Example 2]

A retardation film was obtained in the same manner as in Example 1, except that the preheating temperature was 139 ° C., the stretching temperature was 139 ° C., the draw ratio in the longitudinal direction was 1.25 times, and the draw ratio in the width direction was 2.0 times. The obtained retardation film had a wavelength dispersion value of 1.021, an in-plane retardation Re(550) of 262 nm, a water vapor transmission rate of 83 g/m 2 ·24h, and a phase difference change of 0.9%. The obtained retardation film was used for evaluation of said (4)-(6). A result is shown in Table 1.

[Example 3]

A retardation film was obtained in the same manner as in Example 1 except that the draw ratio in the longitudinal direction was 1.25 times and the draw ratio in the width direction was 2.0 times. The obtained retardation film had a wavelength dispersion value of 1.026, an in-plane retardation Re(550) of 279 nm, a water vapor transmission rate of 81 g/m 2 ·24h, and a change in retardation of 0.8%. The obtained retardation film was used for evaluation of said (4)-(6). A result is shown in Table 1.

[Example 4]

A retardation film was obtained in the same manner as in Example 1 except that the preheating temperature was 139°C and the stretching temperature was 139°C. The obtained retardation film had a wavelength dispersion value of 1.021, an in-plane retardation Re(550) of 271 nm, a water vapor transmission rate of 97 g/m 2 ·24h, and a phase difference change of 1.0%. The obtained retardation film was used for evaluation of said (4)-(6). A result is shown in Table 1.

[Example 5]

A retardation film was obtained in the same manner as in Example 1 except that the preheating temperature was 140°C and the stretching temperature was 140°C. The obtained retardation film had a wavelength dispersion value of 1.022, an in-plane retardation Re(550) of 230 nm, a water vapor transmission rate of 78 g/m 2 ·24h, and a phase difference change of 0.8%. The obtained retardation film was used for evaluation of said (4)-(6). A result is shown in Table 1.

[Example 6]

The retardation film was obtained like Example 1 except the preheating temperature being 138 degreeC and the extending|stretching temperature being 138 degreeC. The obtained retardation film had a wavelength dispersion value of 1.025, an in-plane retardation Re(550) of 300 nm, a water vapor transmission rate of 76 g/m 2 ·24h, and a phase difference change of 0.8%. The obtained retardation film was used for evaluation of said (4)-(6). A result is shown in Table 1.

[Comparative Example 1]

A retardation film was obtained in the same manner as in Example 1 except that a commercially available cycloolefin-based resin film (manufactured by Zeon Corporation, trade name “ZEONOR”) was used as a resin film, and stretching was performed at a preheating temperature of 180°C and a stretching temperature of 175°C. The obtained retardation film had a wavelength dispersion value of 1.01, an in-plane retardation Re (550) of 270 nm, a water vapor transmission rate of 25 g/m 2 ·24 h, and a phase difference change of 0.6%. The obtained retardation film was used for evaluation of said (4)-(6). A result is shown in Table 1.

[Comparative Example 2]

The rubbing treatment was performed by adjusting the rotation axis of the rubbing roller to 45° counterclockwise with respect to the longitudinal direction of the triacetyl cellulose (TAC) film (manufactured by FUJIFILM Corporation). Liquid crystal was applied to the rubbing-treated TAC film to obtain a liquid-crystal-coated triacetyl cellulose (TAC) film. Except having used this liquid-crystal coating TAC film as a resin film, and not having performed extending|stretching, it carried out similarly to Example 1, and obtained retardation film. The obtained retardation film had a wavelength dispersion value of 1.09, an in-plane retardation Re(550) of 260 nm, a water vapor transmission rate of 330 g/m 2 ·24h, and a phase difference change of 4%. The obtained retardation film was used for evaluation of said (4)-(6). A result is shown in Table 1.

As is apparent from Table 1, it can be seen that the retardation film of Examples of the present invention is excellent in water vapor transmission rate, retardation change, mold release processability test, sebum resistance test, and MIT test. It is estimated that this is realized by extending|stretching the resin film containing a specific polycarbonate resin in a specific extending|stretching method and extending|stretching conditions.

(industrial applicability)

The retardation film by embodiment of this invention is used suitably for an image display apparatus.

Claims (10)

Containing a polycarbonate-based resin,
Re (450) / Re (550) is 0.98 ~ 1.03,
Re (550) of 200 nm to 400 nm retardation film. The method of claim 1,
The retardation film in which the said polycarbonate-type resin contains the structural unit derived from the dihydroxy compound represented by following formula (4).

3. The method of claim 2,
The polycarbonate-based resin further comprises a structural unit derived from an alicyclic dihydroxy compound,
The retardation film wherein the alicyclic dihydroxy compound is represented by the following general formula (II), R ¹ is a structure represented by the following (IIb), and n=0.
HOCH ₂ -R ¹ -CH ₂ OH (II)

4. The method according to any one of claims 1 to 3,
The retardation film in which cracks are suppressed in the mold release processability test. 5. The method according to any one of claims 1 to 4,
A retardation film in which whitening and cracking are suppressed in the sebum resistance test. 6. The method according to any one of claims 1 to 5,
Retardation film with more than 500 MIT times. 7. The method according to any one of claims 1 to 6,
A retardation film having a water vapor transmission rate of 100 g/m 2 ·24 h or less. 8. The method according to any one of claims 1 to 7,
A retardation film having a retardation change of 1.0% or less after storage for 500 hours at a temperature of 65°C and a humidity of 90%. A polarizing plate with a retardation layer which has a retardation layer comprised from the retardation film in any one of Claims 1-8, and a polarizer. 10. The method of claim 9,
A polarizing plate with a retardation layer used on the visual recognition side of an image display device.