JP2014095731A - Optical film, polarizing plate and liquid crystal display device - Google Patents

Abstract

An optical film in which a hard coat layer is formed on a thermoplastic substrate made of an acrylic resin has low moisture permeability, hardly causes image unevenness even after exposure to a high humidity environment, and has a high surface hardness. To provide.
An optical film having a hard coat layer formed from a coating composition for forming a hard coat layer on a thermoplastic substrate made of an acrylic resin, comprising: the thermoplastic substrate and the hard coat layer; In the meantime, a permeation layer containing the binder contained in the hard coat layer forming composition and the acrylic resin of the base material is formed.
[Selection figure] None

Description

  The present invention relates to an optical film, a polarizing plate, and a liquid crystal display device.

  In recent years, liquid crystal display devices have been widely used for liquid crystal panels such as liquid crystal televisions, personal computers, mobile phones, and digital cameras. Usually, a liquid crystal display device has a liquid crystal panel member provided with polarizing plates on both sides of a liquid crystal cell, and display is performed by controlling light from the backlight member with the liquid crystal panel member. Here, the polarizing plate is composed of a polarizer and protective films on both sides thereof, and a general polarizer is obtained by dyeing a stretched polyvinyl alcohol (PVA) film with iodine or a dichroic dye to protect it. A cellulose ester film or the like is used as the film.

Recent liquid crystal display devices are becoming more and more demanding, and the demands for durability are becoming stricter as the quality of the liquid crystal display devices increases. For example, when used in outdoor applications, stability against environmental changes is required, and optical films such as the above-described polarizing plate protective film and optical compensation film used in liquid crystal display devices also have dimensions and optical characteristics with respect to temperature and humidity changes. It is required to suppress changes in Problems with liquid crystal display devices exposed to high temperature and high humidity include the occurrence of warpage and display unevenness in the liquid crystal cell of the liquid crystal display device. This is because the polarizing plate and the optical film that composes it absorb and absorb moisture. When this occurs, the balance between the shrinkage of the polarizing plates on the front and back of the liquid crystal cell of the liquid crystal display device causes a difference in the warpage of the liquid crystal cell, and the four corners and four sides of the liquid crystal cell come into contact with the casing and the back side members The cause is considered to be unevenness. For this reason, improvements in humidity dependency and wet heat durability have been sought for protective films and optical compensation films for polarizing plates. The film is required to have a performance that prevents moisture from passing through, that is, low moisture permeability.
For example, Patent Document 1 discloses an optical film obtained by adding a large amount of acrylic resin such as polymethyl methacrylate (PMMA) to cellulose ester.

  In the case where the polarizing plate is used on the entire surface of the liquid crystal cell, it is disposed on the outermost side of the screen, so that it is required to prevent the display surface from being scratched or contaminated with dust or the like. Conventionally, a cover plate made of glass or plastic has been attached to the surface to prevent damage, and the polarizing plate attached to the surface of the liquid crystal cell has been prevented from being damaged. However, providing the cover plate is disadvantageous in terms of cost and thickness, and therefore, it has been studied to perform a hard coat treatment on the polarizing plate surface (Patent Documents 2 and 3).

  It is also known to impart antistatic properties to an optical film in order to prevent contamination due to adhesion of dust or the like. For example, in order to obtain an optical film having antistatic properties and hard coat properties, a conductive compound as an antistatic agent (for example, a conductive polymer) and a polymerizable group serving as a binder are formed on a transparent substrate. It is known to form an antistatic hard coat layer using a coating composition containing a compound having a solvent and a solvent (Patent Document 4). However, a technique that satisfies all of the low moisture permeability, hard coat properties, and antistatic properties has not yet been studied. Furthermore, since materials such as conductive polymers are expensive, in order to impart antistatic properties at low cost, it is required to develop higher antistatic properties with a small amount of conductive polymers.

International Publication No. 2009/047924 JP 2008-247938 A JP 2009-185258 A Japanese Patent No. 46006065

The object of the present invention is to achieve both low moisture permeability and hard coat properties. Furthermore, it is to provide an optical film satisfying all of the antistatic properties in addition to these performances at a low cost.
Another object of the present invention is to provide a polarizing plate using the optical film as a protective film for a polarizing plate, and an image display device having the optical film or the polarizing plate.

The present inventors have intensively studied to solve the above problems and found that the problems can be solved. That is, when a hard coat layer is formed on a substrate made of an acrylic resin having low moisture permeability, after applying a hard coat layer forming coating composition containing a binder and a conductive polymer to the substrate, only a part of the monomer Is to form a permeation layer that permeates the base material selectively. The present inventors have found that the conductive polymer can be concentrated in the hard coat layer, and that excellent antistatic properties can be imparted with a small amount, leading to the present invention.
Furthermore, in earnest study to solve the above problems, it has been found that excellent effects can be obtained by forming a permeation layer even for polymer components other than the conductive polymer. That is, various polymer components may be added to the hard coat layer for the purpose of modifying the film such as brittleness and hardness. As in the case of the conductive polymer, a coating composition for forming a hard coat layer may be used. It was found that when only a part of the monomer is selectively infiltrated after coating, the functional polymer component is concentrated in the hard coat, so that the function can be effectively expressed.
The problem to be solved by the present invention can be solved by the present invention which is the following means.

[1] An optical film having a hard coat layer on a thermoplastic substrate made of an acrylic resin, and is included in the composition for forming a hard coat layer between the thermoplastic substrate and the hard coat layer. An optical film provided with a permeation layer containing a binder and an acrylic resin as a base material.
[2] The film thickness of the hard coat layer is 1 μm or more, and the film thickness of the hard coat layer with respect to the total film thickness of the hard coat layer and the permeation layer is 10% or more and 90% or less. The optical film according to [1].
[3] The optical film as described in [1] or [2], wherein the composition for forming a hard coat layer for forming the hard coat layer contains (a) a polymer component.
[4] The optical film as described in any one of [1] to [3], wherein the polymer component (a) is a conductive polymer.
[5] The hard coat layer forming composition further contains (b) a monomer having two or more unsaturated double bonds in the same molecule, (c) a photopolymerization initiator, and (d) an organic solvent. The optical film according to any one of [1] to [4], wherein
[6] The optical film as described in any one of [1] to [5], wherein the monomer (b) having two or more polymerizable groups in the same molecule (b) has an SP value of 17 to 30. .
[7] The thermoplastic resin acrylic resin is a lactone ring unit represented by the following formula (101),

(Wherein R ¹¹¹ , R ¹¹² and R ¹¹³ each independently represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom.)
Or a glutaric anhydride unit structure represented by the following formula (102)

(In the formula, R ³¹ and R ³² each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom.)
The optical film as described in any one of [1] to [6], comprising:
[8]
A polarizing plate comprising a polarizer and at least one optical film according to any one of [1] to [7] as a protective film for the polarizer.
[9]
A liquid crystal display device comprising: a liquid crystal cell; and the polarizing plate according to [8] disposed in at least one of the liquid crystal cells, wherein the optical film is disposed as an outermost layer.
[10]
A method for producing an optical film having a hard coat layer on a thermoplastic substrate made of an acrylic resin, wherein the thermoplastic substrate is formed by applying a composition for forming a hard coat layer on the thermoplastic substrate. A penetrating layer containing a binder contained in the composition for forming a hard coat layer and a base acrylic resin is formed between the hard coat layer and the hard coat layer.

  According to the present invention, in an optical film in which a hard coat layer is formed on a thermoplastic substrate made of an acrylic resin, low moisture permeability is high, and even when exposed to a high humidity environment, image display unevenness hardly occurs, and surface hardness. And an optical film excellent in antistatic properties can be provided. By using the optical film of the present invention, it is possible to provide a liquid crystal display device in which the occurrence of black display unevenness after a high temperature and high humidity environment has been suppressed.

Below, the optical film of this invention, a polarizing plate, its manufacturing method, the additive used for it, etc. are demonstrated in detail.
The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
“Acrylic resin” means a resin obtained by polymerizing methacrylic acid or a derivative of acrylic acid, and a resin containing the derivative. Further, when not particularly limited, “(meth) acrylate” represents acrylate and methacrylate, and “(meth) acryl” represents acryl and methacryl.

<Optical film>
Hereinafter, the optical film of the present invention will be described.

  The optical film of the present invention is an optical film having a hard coat layer on a thermoplastic substrate made of an acrylic resin, and a composition for forming a hard coat layer between the thermoplastic substrate and the hard coat layer. The penetration layer containing the binder contained in the product and the acrylic resin of the base material is formed. The hard coat layer and the osmotic layer can be formed by applying a coating composition for forming a hard coat layer on a substrate.

{Coating composition for forming hard coat layer}
It preferably contains (a) a polymer component, (b) a monomer having two or more unsaturated double bonds in the same molecule, (c) a photopolymerization initiator, and (d) an organic solvent. (A) Due to poor compatibility between the polymer component and the thermoplastic base material made of acrylic resin, (b) only the monomer having two or more unsaturated double bonds in the same molecule is selectively used as the base material. It can penetrate to form a permeation layer.

(A) Polymer component The polymer component contained in the composition for forming a hard coat layer of the present invention will be described. The polymer component is added to give various functions. For example, adjustment of liquid physical properties such as viscosity and surface tension of the coating composition for forming a hard coat layer, and brittleness and hardness of the hard coat layer are required. Examples thereof include modification, change in appearance such as reflectance, and imparting antistatic properties. In particular, for the purpose of imparting antistatic properties, a conductive polymer is preferably used as the polymer component. Conductive polymers can be broadly classified into ion conductive compounds and electron conductive compounds, which will be described below.

(Ion conductive compound)
The ion conductive compound has high hydrophilicity and extremely low compatibility with a thermoplastic base material made of an acrylic resin described later. Utilizing this property, when the hard coat layer forming coating composition is applied to the substrate, only the compound having an unsaturated double bond described later is allowed to enter the substrate selectively, It is possible to concentrate the ion conductive polymer and improve the antistatic property. Such an effect is considered to be obtained by the electron conductive compound described later, but since the ion conductive compound is more polar, the effect of incompatibility with the base material is more. There is a possibility that it can be obtained greatly.
Examples of the (a) ion conductive compound used in the present invention include cationic, anionic and amphoteric ion conductive compounds.
Among these, cationic and nonionic compounds that can easily obtain the effects of the present invention are preferable, and a compound having a quaternary ammonium base (cationic compound) is particularly preferable from the viewpoint of high antistatic performance of the compound.

As the compound having a quaternary ammonium base, a polymer cationic antistatic agent is more preferably used because there is no fluctuation in antistatic properties due to bleeding out or the like.
As the cationic compound having a polymer type quaternary ammonium base, it can be appropriately selected from known compounds, but is preferably a quaternary ammonium base-containing polymer from the viewpoint of high ion conductivity. A polymer having at least one unit of structural units represented by the following general formulas (I) to (III) is preferable.

In the general formula (I), _{R 1} represents a hydrogen atom, an alkyl group, a halogen atom or _-CH 2 ^COO - represents an ^{M +.} Y represents a hydrogen atom or -COO ^- M ⁺ . M ⁺ represents a proton or a cation. L represents -CONH-, -COO-, -CO- or -O-. J represents an alkylene group, an arylene group, or a group formed by combining these. Q represents a group selected from the following group A.

In the formula, R ₂ , R ₂ ′ and R ₂ ″ each independently represents an alkyl group. J represents an alkylene group, an arylene group, or a group formed by combining these. X ⁻ represents an anion. p and q each independently represents 0 or 1.

In the general formulas (II) and (III), R ₃ , R ₄ , R ₅ and R ₆ each independently represent an alkyl group, and R ₃ and R ₄ and R ₅ and R ₆ are bonded to each other. A nitrogen-containing heterocycle may be formed.
A, B and D are each independently an alkylene group, an arylene group, an alkenylene group, an arylenealkylene _{group, -R 7 COR 8 -, -} R 9 COOR 10 OCOR 11 -, - R 12 OCR 13 COOR 14 -, - _{R 15 - (oR 16) m} -, - R 17 CONHR 18 NHCOR 19 -, - R 20 OCONHR 21 NHCOR 22 - or _-R 23 NHCONHR ₂₄ NHCONHR ₂₅ - represents a. E represents a single bond, an alkylene group, an arylene group, an alkenylene group, an arylene alkylene group, —R ₇ COR ₈ —, —R ₉ COOR ₁₀ OCOR ₁₁ —, —R ₁₂ OCR ₁₃ COOR ₁₄ —, —R ₁₅ — (OR _{16 ) m -, - R 17 CONHR} 18 NHCOR 19 -, - R 20 OCONHR 21 NHCOR 22 - or _-R 23 NHCONHR ₂₄ NHCONHR ₂₅ - or an _-NHCOR 26 CONH-. R ₇ , R ₈ , R ₉ , R ₁₁ , R ₁₂ , R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ , R ₁₉ , R ₂₀ , R ₂₂ , R ₂₃ , R ₂₅ and R ₂₆ represent an alkylene group. R ₁₀ , R ₁₃ , R ₁₈ , R ₂₁ and R ₂₄ each independently represent a linking group selected from an alkylene group, an alkenylene group, an arylene group, an arylene alkylene group and an alkylene arylene group. m represents a positive integer of 1 to 4. X ⁻ represents an anion.
Z ₁ and Z ₂ represent a group of nonmetallic atoms necessary to form a 5-membered or 6-membered ring together with —N═C— group, and are represented by E in the form of a quaternary salt of ≡N ⁺ [X ⁻ ] —. You may connect.
n represents an integer of 5 to 300.

The groups of general formulas (I) to (III) will be described.
Examples of the halogen atom include a chlorine atom and a bromine atom, and a chlorine atom is preferable.
The alkyl group is preferably a branched or straight chain alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group, an ethyl group, or a propyl group.
The alkylene group is preferably an alkylene group having 1 to 12 carbon atoms, more preferably a methylene group, an ethylene group or a propylene group, and particularly preferably an ethylene group.
The arylene group is preferably an arylene group having 6 to 15 carbon atoms, more preferably phenylene, diphenylene, phenylmethylene group, phenyldimethylene group, or naphthylene group, and particularly preferably phenylmethylene group. These groups have a substituent. It may be.
The alkenylene group is preferably an alkylene group having 2 to 10 carbon atoms, and the arylene alkylene group is preferably an arylene alkylene group having 6 to 12 carbon atoms, and these groups may have a substituent.
Examples of the substituent that may be substituted for each group include a methyl group, an ethyl group, and a propyl group.

In general formula (I), R ₁ is preferably a hydrogen atom.
Y is preferably a hydrogen atom.
J is preferably a phenylmethylene group.
Q is preferably the following general formula (VI) selected from group A, and R ₂ , R ₂ ′ and R ₂ ″ are each a methyl group.
X ⁻ includes a halogen ion, a sulfonate anion, a carboxylate anion and the like, preferably a halogen ion, and more preferably a chlorine ion.
p and q are preferably 0 or 1, more preferably p = 0 and q = 1.

In general formulas (II) and (III), R ₃ , R ₄ , R ₅ and R ₆ are preferably a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group. A methyl group is particularly preferred.
A, B and D preferably each independently represent a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, an arylene group, an alkenylene group or an arylene alkylene group, preferably a phenyldimethylene group.
X ⁻ includes a halogen ion, a sulfonate anion, a carboxylate anion and the like, preferably a halogen ion, and more preferably a chlorine ion.
E is preferably E represents a single bond, an alkylene group, an arylene group, an alkenylene group or an arylene alkylene group.
Examples of the 5-membered or 6-membered ring formed by Z ₁ and Z ₂ together with the —N═C— group include a diazoniabicyclooctane ring.

  Specific examples of the compound having units having structures represented by the general formulas (I) to (III) are shown below, but the present invention is not limited thereto. Of the subscripts (m, x, y, r and actual numerical values) in the following specific examples, m represents the number of repeating units of each unit, and x, y, r represents the molar ratio of each unit. .

  The quaternary ammonium base-containing polymer suitably used as the ion conductive compound of the present invention is a polymer other than the structural units (ionic structural units) represented by the general formulas (I) to (III). May have units. By having polymerized units other than ionic structural units in the ion conductive compound, it is expected that the compatibility with the polyethylene oxide compound will be further enhanced and excellent conductivity will be exhibited. In addition, solubility in a solvent and compatibility with a compound having an unsaturated double bond and a photopolymerization initiator can be enhanced.

  The following compounds are mentioned as an example of the monomer which can be used as superposition | polymerization units other than an ionic structural unit.

<Compound (a-2) having an alkylene oxide chain>
The compound (a-2) having an alkylene oxide chain is represented by the following general formula (2). For example, after ring-opening polymerization of ethylene oxide with an alkyl alcohol, transesterification with methyl (meth) acrylate, or (meta ) It can be obtained by reaction with acrylic acid chloride.
^{_{CH 2 = C (R 5)}} COO (AO) n R 6 (2)
(In the formula, R ⁵ represents H or CH ₃ , R ⁶ represents hydrogen or a hydrocarbon group having 1 to 22 carbon atoms, n represents an integer of 2 to 200, and A represents an alkylene group having 2 to 4 carbon atoms. )

In the general formula (2), the alkylene oxide group (AO) is an alkylene oxide group having 2 to 4 carbon atoms, and examples thereof include an ethylene oxide group, a propylene oxide group, and a butylene oxide group. Moreover, the alkylene oxide group from which carbon number differs may exist in the same monomer.
The number (n) of alkylene oxide groups is an integer of 2 to 200, preferably an integer of 10 to 100. In the case of 2 or less, or 101 or more, sufficient compatibility with a compound having an unsaturated double bond described later may not be obtained.
R ⁶ is hydrogen or a hydrocarbon group having 1 to 22 carbon atoms. A carbon number of 23 or more is not practical because the raw material is expensive.
As the hydrocarbon group having 1 to 22 carbon atoms, a substituted or unsubstituted group can be selected, an unsubstituted group is preferable, and an unsubstituted alkyl group is preferable. As the unsubstituted alkyl group, any having or not having a branch can be used. Two or more of these may be used in combination.

  Specific examples of the compound (a-2) having an alkylene oxide chain include, for example, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polybutylene glycol mono (meth) acrylate, poly (ethylene glycol- Propylene glycol) mono (meth) acrylate, poly (ethylene glycol-tetramethylene glycol) mono (meth) acrylate, poly (propylene glycol-tetramethylene glycol) mono (meth) acrylate, polyethylene glycol mono (meth) acrylate monomethyl ether, polyethylene Glycol mono (meth) acrylate monobutyl ether, polyethylene glycol mono (meth) acrylate monooctyl ether, polyethylene glycol Cole mono (meth) acrylate monobenzyl ether, polyethylene glycol mono (meth) acrylate monophenyl ether, polyethylene glycol mono (meth) acrylate monodecyl ether, polyethylene glycol mono (meth) acrylate monododecyl ether, polyethylene glycol mono (meth) acrylate Monotetradecyl ether, polyethylene glycol mono (meth) acrylate monohexadecyl ether, polyethylene glycol mono (meth) acrylate monooctadecyl ether poly (ethylene glycol-propylene glycol) mono (meth) acrylate octyl ether, poly (ethylene glycol-propylene glycol) ) Mono (meth) acrylate octadecyl ether, poly (ethylene) Glycol - propylene glycol) mono (meth) acrylate nonylphenyl ether.

<Compound (a-3) copolymerizable with (a-2)>
Furthermore, you may radically copolymerize the compound (a-3) copolymerizable with the said (a-2) as needed.
The compound (a-3) copolymerizable with (a-2) is not particularly limited as long as it is a compound having one ethylenically unsaturated group. For example, methyl (meth) acrylate, ethyl Alkyl (meth) acrylates such as (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate; hydroxyethyl (meth) acrylate , Hydroxyalkyl (meth) acrylates such as hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate; benzyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) Various types (meth) such as acrylate, dicyclopentenyloxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate, butoxyethyl (meth) acrylate, cyanoethyl (meth) acrylate, glycidyl (meth) acrylate, etc. ) Acrylate, styrene, methylstyrene and the like.

  The conductive compounds exemplified above may be used alone, or two or more compounds may be used in combination. In addition, an antistatic compound having a polymerizable group in the molecule of the antistatic agent is more preferable because it can improve the scratch resistance (film strength) of the antistatic layer.

  (A) As an ion conductive compound, a commercial item can also be used, for example, a product name "Rioduras LAS-1211" (made by Toyo Ink Manufacturing Co., Ltd.), a product name "purple UV-AS-102" (Japan) Synthetic Drugs Co., Ltd.), “NK Oligo U-601, 201” (manufactured by Shin-Nakamura Chemical Co., Ltd.) and the like.

(Electron conductive compound)
As the polymer component of the present invention, an electron conductive compound can also be suitably used. The electron conductive compound is preferably a non-conjugated polymer or a conjugated polymer in which aromatic carbocycles or aromatic heterocycles are connected by a single bond or a divalent or higher linking group. Examples of the aromatic carbocyclic ring in the non-conjugated polymer or conjugated polymer include a benzene ring, and may further form a condensed ring. Examples of the aromatic heterocycle in the non-conjugated polymer or conjugated polymer include a pyridine ring, a birazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, an oxazole ring, a thiazole ring, an imidazole ring, an oxadiazole ring, a thiadiazole ring, Examples include triazole ring, tetrazole ring, furan ring, thiophene ring, pyrrole ring, indole ring, carbazole ring, benzimidazole ring, imidazopyridine ring, etc. Also good.

  The divalent or higher linking group in the non-conjugated polymer or conjugated polymer includes a linking group formed of a carbon atom, a silicon atom, a nitrogen atom, a boron atom, an oxygen atom, a sulfur atom, a metal, a metal ion, or the like. Is mentioned. Preferably, it is a group formed from a carbon atom, a nitrogen atom, a silicon atom, a boron atom, an oxygen atom, a sulfur atom and a combination thereof, and the group formed by the combination includes a substituted or unsubstituted methylene group, carbonyl Group, imino group, sulfonyl group, sulfinyl group, ester group, amide group, silyl group and the like.

  Specific examples of the electron conductive compound include substituted or unsubstituted conductive polyaniline, polyparaphenylene, polyparaphenylene vinylene, polythiophene, polyfuran, polypyrrole, polyselenophene, polyisothianaphthene, polyphenylene sulfide, polyacetylene, Examples thereof include polypyridyl vinylene, polyazine, and derivatives thereof. These may use only 1 type and may use it in combination of 2 or more type according to the objective.

  Moreover, as long as desired conductivity can be achieved, it can also be used as a mixture with other polymers that do not have conductivity, and a monomer that can form a conductive polymer and other monomers that do not have conductivity. Copolymers can also be used.

The electron conductive compound is more preferably a conjugated polymer. Examples of conjugated polymers include polyacetylene, polydiacetylene, poly (paraphenylene), polyfluorene, polyazulene, poly (paraphenylene sulfide), polypyrrole, polythiophene, polyisothianaphthene, polyaniline, poly (paraphenylene vinylene), poly (2,5-thienylene vinylene), double chain conjugated polymers (such as polyperinaphthalene), metal phthalocyanine polymers, other conjugated polymers (poly (paraxylylene), poly [α- (5,5 ' -Bithiophenediyl) benzylidene], etc.), or derivatives thereof.
Preferred examples include poly (paraphenylene), polypyrrole, polythiophene, polyaniline, poly (paraphenylene vinylene), and poly (2,5-thienylene vinylene), more preferred are polythiophene, polyaniline, polypyrrole, and derivatives thereof, and more preferred. Includes at least one of polythiophene and derivatives thereof.
These conjugated polymers may have a substituent. Examples of the substituent which these conjugated polymer has, can be exemplified by the substituents described as R ⁷¹ in the general formula (IV) below.

  In particular, the viewpoint that an electron conductive compound having a partial structure represented by the following general formula (IV) (that is, polythiophene and its derivatives) obtains an optical film having both high transparency and antistatic properties. To preferred.

In the general formula (IV), R ⁷¹ represents a substituent, and m11 represents an integer of 0 to 2. When m11 represents 2, the plurality of R ⁷¹ may be the same as or different from each other, and may be connected to each other to form a ring. n11 represents an integer of 1 or more.

Examples of the substituent represented by R ⁷¹ include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, still more preferably 1 to 8 carbon atoms, such as methyl, ethyl, iso-propyl, etc. , Tert-butyl, 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, Particularly preferred are those having 2 to 8 carbon atoms, such as vinyl, allyl, 2-butenyl, 3-pentenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 2-octenyl and the like, and alkynyl groups (preferably). Has 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, such as propargyl , 3-pentynyl, etc.), an aryl group (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyl, p-methylphenyl, Naphthyl and the like), an amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, Dibenzylamino, diphenylamino, etc.),

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, hexyloxy, octyloxy, etc.), An aryloxy group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, and particularly preferably 6 to 12 carbon atoms, such as phenyloxy and 2-naphthyloxy), an acyl group ( Preferably it has 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include acetyl, benzoyl, formyl, pivaloyl and the like, and an alkoxycarbonyl group (preferably carbon). 2-20, more preferably 2-16 carbon atoms, particularly preferably 2-12 carbon atoms, for example methoxy And aryloxycarbonyl groups (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, and particularly preferably having 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, and examples thereof include methoxycarbonylamino and the like, an aryloxycarbonylamino group (preferably 7 to 20 carbon atoms, more preferably carbon atoms). 7 to 16, particularly preferably 7 to 12 carbon atoms, for example 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, such as methanesulfonylamino, benzenesulfonylamino, etc. ), 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, phenylsulfuryl). Famoyl etc.),

A carbamoyl 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 carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl and the like), alkylthio. A 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 and ethylthio), an arylthio group (preferably having 6 to 6 carbon atoms). 20, More preferably, it is C6-C16, Most preferably, it is C6-C12, for example, phenylthio etc. are mentioned, A sulfonyl group (Preferably C1-C20, More preferably C1-C16 , Particularly preferably having 1 to 12 carbon atoms, such as mesyl and tosyl). Rufinyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably carbon 1 to 20, 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 carbon atom) -20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as diethyl phosphoric acid amide and phenyl phosphoric acid amide).

Hydroxy group, mercapto group, halogen atom (eg 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 ring Group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom, and a sulfur atom. Specifically, for example, pyrrolidine, piperidine, piperazine, Morpholine, thiophene, furan, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazoline, thiazole, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, isoquinoline, phthala , Naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzthiazole, benzotriazole, tetrazaindene, etc.), silyl group (preferably having 3 carbon atoms) -40, more preferably 3-30, particularly preferably 3-24, and examples thereof include trimethylsilyl, triphenylsilyl, and the like.

The substituent represented by R ⁷¹ may be further substituted. Moreover, when it has two or more substituents, those substituents may mutually be the same or different, and if possible, they may be connected to form a ring. Examples of the ring formed include a cycloalkyl ring, a benzene ring, a thiophene ring, a dioxane ring, and a dithiane ring.

The substituent represented by R ⁷¹ is preferably an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, or an alkylthio group, and more preferably an alkyl group, an alkoxy group, or an alkylthio group. Particularly preferably, when m11 is 2, it is preferable that two R ^71s are an alkoxy group or an alkylthio group in which a ring is formed to form a dioxane ring or a dithiane ring.

In the general formula (IV), when m11 is 1, R ⁷¹ is preferably an alkyl group, and more preferably an alkyl group having 2 to 8 carbon atoms.
n11 is not particularly limited as long as it is an integer of 1 or more, but is preferably an integer of 1 to 1000.
Further, when R ⁷¹ is poly (3-alkylthiophene) which is an alkyl group, the connection modes with adjacent thiophene rings are all stereoregular connected by 2-5 ′, and 2-2 ′. , 5-5 'linkages are included, but sterically irregular ones are preferred.

  In the present invention, as the electron conductive compound, since the hydrophilicity is relatively high, the compatibility with the base material is low, the formability of the permeation layer and the hard coat layer is excellent, and from the viewpoint of excellent conductivity, It is particularly preferable that poly (3,4-ethylenedioxy) thiophene (the following specific example compound (6), PEDOT) is contained as a main component.

Polythiophene represented by the general formula (IV) and derivatives thereof are described in J. Org. Mater. Chem. 2005, 15, 2077-2088. And Advanced Materials 2000, 12 (7), page 481, and the like. Further, as commercially available products, Denatron P502 (manufactured by Nagase Chemtech), 3,4-ethylenedioxythiophene (BAYTRON (registered trademark) MV2), 3,4-polyethylenedithiothiopene / polystyrenesulfate (BAYTRON (registered trademark), BAYTRON (registered trademark)) (Trademark) C), BAYTRON (registered trademark) FE, BAYTRON (registered trademark) M V2, BAYTRON (registered trademark) P, BAYTRON (registered trademark) P AG, BAYTRON (registered trademark) PHC V4, BAYTRON (registered trademark) PH, BAYTRON (registered trademark) PH, BAYTRON (registered trademark) PH 500, BAYTRON (registered trademark) PH 510 (above, Stark ) Can be obtained and the like.
Polyaniline (manufactured by Aldrich), polyaniline (eleraldine salt) (manufactured by Aldrich) and the like can be obtained as polyaniline and derivatives thereof.
Polypyrrole (manufactured by Aldrich) and the like can be obtained as polypyrrole and derivatives thereof.

Although the specific example of a conductive polymer is shown below, this invention is not limited to these. In addition to these, compounds described in International Publication No. 98/01909 and the like can be mentioned.
In the following formulae, x and y each independently represents an integer of 1 or more.

  The weight average molecular weight of the polymer component (a) used in the present invention is preferably 3,000 to 1,000,000, more preferably 10,000 to 500,000, still more preferably 10,000 to 100,000. It is. Here, the weight average molecular weight is a polystyrene-converted weight average molecular weight measured by gel permeation chromatography.

  From the viewpoint that the content of the polymer component (a) in the composition for forming a hard coat layer of the present invention is an amount sufficient to impart antistatic properties and the film hardness is difficult to deteriorate, 1 mass%-30 mass% are preferable with respect to the total solid in a composition, 3 mass%-20 mass% are more preferable, and 5 mass%-15 mass% are still more preferable.

(Compound having an unsaturated double bond)
Next, the compound which has the unsaturated double bond contained in the composition for hard-coat layer formation of this invention is demonstrated.
The compound having an unsaturated double bond can function as a binder, and (b) is preferably a monomer having two or more unsaturated double bonds in the same molecule. The monomer having two or more unsaturated double bonds in the same molecule can function as a curing agent, and can improve the strength and scratch resistance of the coating film. The number of polymerizable unsaturated groups is more preferably 3 or more.

(B) Examples of the monomer having two or more unsaturated double bonds in the same molecule include compounds having a polymerizable functional group such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. , (Meth) acryloyl groups and —C (O) OCH═CH ₂ are preferred. Particularly preferably, a compound containing three or more (meth) acryloyl groups in one molecule described below can be used.

  Specific examples of the compound having a polymerizable unsaturated bond include (meth) acrylic acid diesters of alkylene glycol, (meth) acrylic acid diesters of polyoxyalkylene glycol, and (meth) acrylic acid diesters of polyhydric alcohol. , (Meth) acrylic acid diesters of ethylene oxide or propylene oxide adducts, epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, and the like.

  Among these, esters of polyhydric alcohol and (meth) acrylic acid are preferable. For example, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate , Pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, PO modified trimethylolpropane tri (meth) acrylate, EO modified Tri (meth) acrylate phosphate, trimethylolethane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate Rate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate, caprolactone-modified tris (acryloxyethyl) isocyanurate, etc. Can be mentioned.

Commercially available polyfunctional acrylate compounds having a (meth) acryloyl group can be used, such as KAYARAD DPHA manufactured by Nippon Kayaku Co., Ltd., PET-30, Shin Nakamura Chemical Co., Ltd., NK Ester A -TMMT, A-TMPT, etc. can be mentioned.
Non-fluorinated polyfunctional monomers are described in paragraphs [0114] to [0122] of JP-A-2009-98658, and the same applies to the present invention.

The compound having an unsaturated double bond in the composition for forming a hard coat layer of the present invention has an SP value of preferably 17 to 30, more preferably 19 to 25, from the viewpoint of easy penetration into the substrate. 23 is more preferable.
The SP value (solubility parameter) in the present invention is a value calculated by the Hoy method, and the Hoy method is described in POLYMER HANDBOOK FOURTH EDITION.

  The content of the compound having an unsaturated double bond in the composition for forming a hard coat layer of the present invention provides a sufficient polymerization rate and imparts hardness and the like, so in the composition for forming an antistatic hard coat layer. 40-98 mass% is preferable with respect to the total solid of, and 60-95 mass is more preferable.

(Polymerization initiator)
The composition for forming a hard coat layer (hereinafter also referred to as composition) used in the present invention preferably contains a polymerization initiator, and (c) a photopolymerization initiator is preferred as the polymerization initiator.
As photopolymerization initiators, acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds, Examples include fluoroamine compounds, aromatic sulfoniums, lophine dimers, onium salts, borate salts, active esters, active halogens, inorganic complexes, and coumarins. Specific examples, preferred embodiments, commercially available products, and the like of the photopolymerization initiator are described in paragraphs [0133] to [0151] of JP-A-2009-098658, and can be suitably used in the present invention as well. it can.

  “Latest UV Curing Technology” {Technical Information Association, Inc.} (1991), p. 159, and “UV Curing System” written by Kiyomi Kato (published by the General Technology Center in 1989), p. Various examples are also described in 65-148 and are useful in the present invention.

  Commercially available photocleavable photoradical polymerization initiators include “Irgacure 651”, “Irgacure 184”, “Irgacure 819”, “Irgacure 907”, “Irgacure 1870” (CGI) manufactured by Ciba Specialty Chemicals Co., Ltd. -403 / Irgacure 184 = 7/3 mixing initiator), "Irgacure 500", "Irgacure 369", "Irgacure 1173", "Irgacure 2959", "Irgacure 4265", "Irgacure 4263", "Irgacure 127", " OXE01 ”, etc .;“ Kayacure DETX-S ”,“ Kayacure BP-100 ”,“ Kayacure BDK ”,“ Kayacure CTX ”,“ Kayacure BMS ”,“ Kayacure 2-EAQ ”,“ Cayacure ”manufactured by Nippon Kayaku Co., Ltd. "ABQ", " “Yacure CPTX”, “Kayacure EPD”, “Kayacure ITX”, “Kayacure QTX”, “Kayacure BTC”, “Kayacure MCA”, etc .; , KIP150, TZT) ", etc., and combinations thereof are preferred examples.

  The content of the photopolymerization initiator used in the present invention is set so that the polymerizable compound contained in the composition is polymerized and the starting point is set so as not to increase too much. 0.5-8 mass% is preferable with respect to the total solid content in it, and 1-5 mass% is more preferable.

(solvent)
The composition used in the present invention preferably contains a solvent. As the solvent, various solvents can be used in consideration of the solubility of the monomer, the drying property at the time of coating, the dispersibility of the translucent particles, etc., but the monomer in the coating composition for forming the hard coat layer is based on the solvent. In order to easily enter the material and form a permeation layer, it is preferable to contain a solvent that can dissolve the thermoplastic base material made of acrylic resin. Examples of the organic solvent carbonic acid include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, acetone, methyl ethyl ketone (MEK), cyclopentanone, cyclohexanone methyl acetate, and ethyl acetate. It doesn't depend on this. Examples of various organic solvents that can be used include dibutyl ether, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrofuran, and anisole. , Phenetole, diethyl ketone, dipropyl ketone, diisobutyl ketone, methylcyclohexanone, ethyl formate, propyl formate, pentyl formate, propyl acetate, methyl propionate, ethyl propionate, γ-ptyrolactone, methyl 2-methoxyacetate, 2-ethoxyacetic acid Methyl, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropionate, 2-methoxyethanol, 2-propoxyethanol, 2-butoxyethanol, 1,2-diacetoxyacetone, acetylacetone, diacetate Methyl alcohol such as alcohol, methyl acetoacetate, ethyl acetoacetate, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, cyclohexyl alcohol, isobutyl acetate, methyl isobutyl ketone (MIBK), 2-octanone, 2-pentanone, 2-hexanone, ethylene Glycol ethyl ether, ethylene glycol isopropyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, ethyl carbitol, butyl carbitol, hexane, heptane, octane, cyclohexane, methylcyclohexane, ethylcyclohexane, benzene, toluene, xylene, etc. These can be used singly or in combination of two or more.

  It is preferable to use a solvent so that the solid content of the composition used in the present invention is in the range of 20 to 80% by mass, more preferably 30 to 75% by mass, and still more preferably 40 to 70% by mass. It is.

(Surfactant)
It is also suitable to use various surfactants in the composition for forming a hard coat layer of the present invention. In general, a surfactant may suppress unevenness in film thickness due to variation in drying due to local distribution of drying air, and may improve surface unevenness and repellency of a coated material. Furthermore, by improving the dispersibility of the conductive polymer, it may be more stable and high conductivity may be expressed, which is preferable.

  Specifically, the surfactant is preferably a fluorine-based surfactant or a silicone-based surfactant. Further, the surfactant is preferably an oligomer or a polymer rather than a low molecular compound.

  When a surfactant is added, the surfactant quickly moves to the surface of the applied liquid film and becomes unevenly distributed, and the surfactant is unevenly distributed on the surface even after the film is dried. The surface energy of the hard coat layer is lowered by the surfactant. From the viewpoint of preventing non-uniformity in film thickness, repellency, and unevenness of the antistatic layer, the surface energy of the film is preferably low.

  Preferred embodiments and specific examples of the fluorosurfactant are described in paragraph numbers [0023] to [0080] of JP-A-2007-102206, and the same applies to the present invention.

  Preferable examples of the silicone surfactant include those having a substituent at the end of the compound chain and / or the side chain, containing a plurality of dimethylsilyloxy units as repeating units. The compound chain containing dimethylsilyloxy as a repeating unit may contain a structural unit other than dimethylsilyloxy. The substituents may be the same or different, and a plurality of substituents are preferable. Examples of preferred substituents include groups containing a polyether group, an alkyl group, an aryl group, an aryloxy group, an aryl group, a cinnamoyl group, an oxetanyl group, a fluoroalkyl group, a polyoxyalkylene group, and the like.

  Although there is no restriction | limiting in particular in molecular weight, It is preferable that it is number average molecular weight 100,000 or less, It is more preferable that it is 50,000 or less, It is especially preferable that it is 1000-30000, It is most preferable that it is 1000-20000.

Examples of preferable silicone compounds include “X-22-174DX”, “X-22-2426”, “X22-164C”, “X-22-176D” (manufactured by Shin-Etsu Chemical Co., Ltd.) (Trade name); “FM-7725”, “FM-5521”, “FM-6621”, (product name) manufactured by Chisso Corporation; “DMS-U22”, “RMS-033” (manufactured by Gelest) Product name); “SH200”, “DC11PA”, “ST80PA”, “L7604”, “FZ-2105”, “L-7604”, “Y-7006”, “SS” manufactured by Toray Dow Corning Co., Ltd. -2801 "(above product name);" TSF400 "(product name); manufactured by Momentive Performance Materials Japan, but is not limited thereto.
The surfactant is preferably contained in the total solid content of the coating composition for forming an antistatic hard coat layer in an amount of 0.01 to 0.5% by mass, more preferably 0.01 to 0.3% by mass. preferable.

(Translucent resin particles)
Various optically transparent resin particles can be used for the optical film of the present invention in order to impart antiglare properties (surface scattering properties) and internal scattering properties. Since the translucent resin particles cannot penetrate into the base material, they exist in the hard coat layer.

As the translucent resin particles have no variation in particle size, the scattering characteristics are less varied and the design of the haze value becomes easier. As the translucent particles, plastic beads are preferable, and those having particularly high transparency and a difference in refractive index with the binder are preferable.
As organic particles, polymethyl methacrylate particles (refractive index 1.49), crosslinked poly (acryl-styrene) copolymer particles (refractive index 1.54), melamine resin particles (refractive index 1.57), polycarbonate particles ( Refractive index 1.57), polystyrene particles (refractive index 1.60), crosslinked polystyrene particles (refractive index 1.61), polyvinyl chloride particles (refractive index 1.60), benzoguanamine-melamine formaldehyde particles (refractive index 1. 68) etc. are used.

  Of these, cross-linked polystyrene particles, cross-linked poly ((meth) acrylate) particles, and cross-linked poly (acryl-styrene) particles are preferably used, and a binder is selected according to the refractive index of each light-transmitting particle selected from these particles. By adjusting the refractive index, the internal haze, surface haze, and centerline average roughness of the present invention can be achieved.

  The difference in refractive index between the hard coat layer of the present invention and the translucent resin particles (the refractive index of the translucent particles−the refractive index of the hard coat layer) is preferably 0.001 to 0.030 as an absolute value. . When the difference in refractive index is within this range, problems such as film character blurring, dark room contrast reduction, and surface turbidity do not occur.

  The average particle diameter (volume basis) of the translucent resin particles is preferably 0.5 to 20 μm. When the average particle diameter is within this range, the light scattering angle distribution does not become too wide, and there is no character blur on the display.

  Moreover, you may use together and use 2 or more types of translucent resin particles from which a particle diameter differs. It is possible to impart an antiglare property with a light-transmitting resin particle having a larger particle diameter, and to reduce surface roughness with a light-transmitting particle having a smaller particle diameter.

  When blending the translucent particles, it is preferably blended so as to be contained in an amount of 3 to 30% by mass in the total solid content of the antistatic hard coat layer. When the content is within this range, problems such as image blur, surface turbidity and glare can be prevented, and antistatic properties are not impaired.

{Thermoplastic substrate made of acrylic resin}
A thermoplastic base material made of an acrylic resin (hereinafter also referred to as a base film) has a (meth) acrylic polymer as a main component. In the present application, that the base film is mainly composed of a (meth) acrylic polymer means that the base film contains 50% by mass or more of the (meth) acrylic polymer.

  The (meth) acrylic polymer is a concept including both a methacrylic polymer and an acrylic polymer. The (meth) acrylic polymer also includes acrylate / methacrylate derivatives, in particular, acrylate ester / methacrylate ester (co) polymers.

((Meth) acrylic polymer)
The (meth) acrylic acid polymer preferably has a repeating structural unit derived from a (meth) acrylic acid ester monomer as a repeating structural unit.

  The (meth) acrylic acid polymer further polymerizes at least one selected from a hydroxyl group-containing monomer, an unsaturated carboxylic acid, and a monomer represented by the following general formula (201) as a repeating structural unit. It may contain a repeating structural unit constructed as described above.

Formula (201)
CH ₂ = C (X) R ²⁰¹

(In the formula, R ²⁰¹ represents a hydrogen atom or a methyl group, and X represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, a —CN group, a —CO—R ²⁰² group, or —O—CO—R. ²⁰³ represents a group, and R ²⁰² and R ²⁰³ represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)

The (meth) acrylic acid ester is not particularly limited, and examples thereof include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, cyclohexyl acrylate, and benzyl acrylate. Acrylic acid esters; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, methacrylic acid esters such as benzyl methacrylate; These may be used alone or in combination of two or more. Among these, methyl methacrylate is particularly preferable from the viewpoint of excellent heat resistance and transparency.
When the (meth) acrylic acid ester is used, the content ratio in the monomer component to be subjected to the polymerization step is preferably 10 to 100% by mass, more preferably 10 in order to sufficiently exhibit the effects of the present invention. -100 mass%, More preferably, it is 40-100 mass%, Most preferably, it is 50-100 mass%.

The hydroxyl group-containing monomer is not particularly limited. For example, 2- (hydroxyalkyl) acrylic acid ester such as α-hydroxymethylstyrene, α-hydroxyethylstyrene, methyl 2- (hydroxyethyl) acrylate; 2 2- (hydroxyalkyl) acrylic acid such as-(hydroxyethyl) acrylic acid; and the like. These may be used alone or in combination of two or more.
In the case of using the hydroxyl group-containing monomer, the content ratio in the monomer component to be subjected to the polymerization step is preferably 0 to 30% by mass, more preferably 0 to 0% in order to sufficiently exhibit the effects of the present invention. 20 mass%, More preferably, it is 0-15 mass%, Most preferably, it is 0-10 mass%.

Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, α-substituted acrylic acid, α-substituted methacrylic acid and the like. These may be used alone or in combination of two or more. You may use together. Among these, acrylic acid and methacrylic acid are preferable in that the effects of the present invention are sufficiently exhibited.
When the unsaturated carboxylic acid is used, the content ratio in the monomer component to be subjected to the polymerization step is preferably 0 to 30% by mass, more preferably 0 to 20%, in order to sufficiently exhibit the effects of the present invention. It is 0 mass%, More preferably, it is 0-15 mass%, Most preferably, it is 0-10 mass%.

Examples of the monomer represented by the general formula (201) include styrene, vinyl toluene, α-methyl styrene, acrylonitrile, methyl vinyl ketone, ethylene, propylene, vinyl acetate, and the like. You may use, and may use 2 or more types together. Among these, styrene and α-methylstyrene are particularly preferable in that the effects of the present invention are sufficiently exhibited.
When using the monomer represented by the general formula (201), the content ratio in the monomer component to be subjected to the polymerization step is preferably 0 to 30 mass in order to sufficiently exhibit the effects of the present invention. %, More preferably 0 to 20% by mass, still more preferably 0 to 15% by mass, and particularly preferably 0 to 10% by mass.

[(Meth) acrylic polymer having a ring structure in the main chain]
Among (meth) acrylic polymers, those having a ring structure in the main chain are preferred. By introducing a ring structure into the main chain, the rigidity of the main chain can be improved and the heat resistance can be improved.
In the present invention, among (meth) acrylic polymers having a ring structure in the main chain, a polymer having a lactone ring structure in the main chain, a polymer having a glutaric anhydride ring structure in the main chain, and a glutarimide ring in the main chain It is preferably any of polymers having a structure. Among these, a polymer containing a lactone ring structure in the main chain is more preferable.
The following polymers having a ring structure in these main chains will be described in order.

((Meth) acrylic polymer with lactone ring structure in the main chain)
The (meth) acrylic polymer having a lactone ring structure in the main chain (hereinafter also referred to as a lactone ring-containing polymer) is not particularly limited as long as it is a (meth) acrylic polymer having a lactone ring in the main chain, but preferably Has a lactone ring structure represented by the following general formula (101).

In formula (401), R ¹¹¹ , R ¹¹² and R ¹¹³ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms, and the organic residue may contain an oxygen atom. . Here, the organic residue having 1 to 20 carbon atoms is preferably a methyl group, an ethyl group, an isopropyl group, an n-butyl group, a t-butyl group, or the like.

  The content ratio of the lactone ring structure represented by the general formula (101) in the structure of the lactone ring-containing polymer is preferably 5 to 90% by mass, more preferably 10 to 70% by mass, and still more preferably 10 to 60% by mass. %, Particularly preferably 10 to 50% by mass. By setting the content ratio of the lactone ring structure to 5% by mass or more, the heat resistance and surface hardness of the obtained polymer tend to be improved, and by setting the content ratio of the lactone ring structure to 90% by mass or less. The moldability of the obtained polymer tends to be improved.

  The method for producing the lactone ring-containing polymer is not particularly limited, but preferably, after obtaining a polymer (p) having a hydroxyl group and an ester group in the molecular chain by a polymerization step, the obtained polymer ( It is obtained by carrying out a lactone cyclization condensation step for introducing a lactone ring structure into the polymer by heat-treating p).

  The mass average molecular weight of the lactone ring-containing polymer is preferably 1,000 to 2,000,000, more preferably 5,000 to 1,000,000, still more preferably 10,000 to 500,000, particularly preferably. 50,000 to 500,000.

  The lactone ring-containing polymer has a mass reduction rate within a range of 150 to 300 ° C. in dynamic TG measurement, preferably 1% or less, more preferably 0.5% or less, and still more preferably 0.3% or less. It is good. As a method for measuring dynamic TG, the method described in JP-A-2002-138106 can be used.

  Since the lactone ring-containing polymer has a high cyclization condensation reaction rate, there is little dealcoholization reaction in the production process of the molded product, and bubbles and silver stripes (silver streaks) are formed in the molded product after molding due to the alcohol. The disadvantage of entering can be avoided. Furthermore, since the lactone ring structure is sufficiently introduced into the polymer due to a high cyclization condensation reaction rate, the obtained lactone ring-containing polymer has high heat resistance.

  The lactone ring-containing polymer has a coloring degree (YI) of preferably 6 or less, more preferably 3 or less, still more preferably 2 or less, and particularly preferably 1 or less when a chloroform solution having a concentration of 15% by mass is used. . If the degree of coloring (YI) is 6 or less, problems such as loss of transparency due to coloring are unlikely to occur, and therefore, it can be preferably used in the present invention.

  The lactone ring-containing polymer has a 5% mass reduction temperature in thermal mass spectrometry (TG) of preferably 330 ° C. or higher, more preferably 350 ° C. or higher, and still more preferably 360 ° C. or higher. The 5% mass reduction temperature in thermal mass spectrometry (TG) is an indicator of thermal stability, and by setting it to 330 ° C. or higher, sufficient thermal stability tends to be exhibited. The thermal mass spectrometry can use the apparatus for measuring the dynamic TG.

  The lactone ring-containing polymer has a glass transition temperature (Tg) of preferably 115 ° C. or higher, more preferably 125 ° C. or higher, further preferably 130 ° C. or higher, particularly preferably 135 ° C. or higher, and most preferably 140 ° C. or higher. .

  The total amount of residual volatile components contained in the lactone ring-containing polymer is preferably 5,000 ppm or less, more preferably 2,000 ppm or less, still more preferably 1,500 ppm, and particularly preferably 1,000 ppm. If the total amount of residual volatile components is 5,000 ppm or less, it is preferable because coloring defects due to alteration during molding, foaming, and molding defects such as silver streak are unlikely to occur.

  The lactone ring-containing polymer has a total light transmittance of 85% or more, more preferably 88% or more, and still more preferably measured by a method based on ASTM-D-1003 for a molded product obtained by injection molding. 90% or more. The total light transmittance is an index of transparency, and when it is 85% or more, the transparency tends to be improved.

In the case of a polymerization form using a solvent, the polymerization solvent is not particularly limited. For example, aromatic hydrocarbon solvents such as toluene, xylene, and ethylbenzene; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ether solvents such as tetrahydrofuran Etc., and only one of these may be used, or two or more may be used in combination.
In the first aspect of the production method of the present invention, the (meth) acrylic resin is dissolved in an organic solvent and cast by solution casting. Therefore, the organic solvent at the time of synthesizing the (meth) acrylic resin is There is no limitation as compared with the case of performing melt film formation, and synthesis may be performed using an organic solvent having a high boiling point.

During the polymerization reaction, a polymerization initiator may be added as necessary. Although it does not specifically limit as a polymerization initiator, For example, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, t-amyl Organic peroxides such as peroxy-2-ethylhexanoate; 2,2′-azobis (isobutyronitrile), 1,1′-azobis (cyclohexanecarbonitrile), 2,2′-azobis (2, Azo compounds such as 4-dimethylvaleronitrile), and the like. These may be used alone or in combination of two or more. The amount of the polymerization initiator used is not particularly limited as long as it is appropriately set according to the combination of the monomers used and the reaction conditions.
The weight average molecular weight of the polymer can be adjusted by adjusting the amount of the polymerization initiator.

  When performing the polymerization, it is preferable to control the concentration of the produced polymer in the polymerization reaction mixture to be 50% by mass or less in order to suppress gelation of the reaction solution. Specifically, when the concentration of the produced polymer in the polymerization reaction mixture exceeds 50% by mass, it is preferable that the polymerization solvent is appropriately added to the polymerization reaction mixture and controlled to be 50% by mass or less. . The concentration of the produced polymer in the polymerization reaction mixture is more preferably 45% by mass or less, still more preferably 40% by mass or less.

  The form in which the polymerization solvent is appropriately added to the polymerization reaction mixture is not particularly limited, and the polymerization solvent may be added continuously or intermittently. By controlling the concentration of the produced polymer in the polymerization reaction mixture in this way, the gelation of the reaction solution can be more sufficiently suppressed. The polymerization solvent to be added may be the same type of solvent used during the initial charging of the polymerization reaction or may be a different type of solvent, but is the same as the solvent used during the initial charging of the polymerization reaction. It is preferable to use different types of solvents. Further, the polymerization solvent to be added may be only one type of solvent or a mixed solvent of two or more types.

(Polymer having glutaric anhydride ring structure in the main chain)
The polymer having a glutaric anhydride ring structure in the main chain represents a polymer having glutaric anhydride units.

  The polymer having a glutaric anhydride unit preferably has a glutaric anhydride unit represented by the following general formula (102) (hereinafter referred to as a glutaric anhydride unit).

  Formula (102):

In the general formula ^{(102), R 31, R} 32 each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom. R ³¹ and R ³² particularly preferably represent the same or different hydrogen atoms or alkyl groups having 1 to 5 carbon atoms.

  The polymer having a glutaric anhydride unit is preferably a (meth) acrylic polymer containing a glutaric anhydride unit. The (meth) acrylic polymer preferably has a glass transition temperature (Tg) of 120 ° C. or higher from the viewpoint of heat resistance.

  As content of the glutaric anhydride unit with respect to a (meth) acrylic-type polymer, 5-50 mass% is preferable, More preferably, it is 10-45 mass%. When the content is 5% by mass or more, more preferably 10% by mass or more, an effect of improving heat resistance can be obtained, and further an effect of improving weather resistance can be obtained.

Moreover, it is preferable that said (meth) acrylic-type copolymer contains the repeating unit based on unsaturated carboxylic-acid alkylester further. As the repeating unit based on the unsaturated carboxylic acid alkyl ester, for example, those represented by the following general formula (103) are preferred.
Formula _{(103): - [CH 2} -C (R 41) (COOR 42)] -

In General Formula (103), R ⁴¹ represents hydrogen or an alkyl group having 1 to 5 carbon atoms, R ⁴² ) represents an aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms, or one or more carbon atoms inclusive. Represents an aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms substituted by the number of hydroxyl groups or halogen.

The monomer corresponding to the repeating unit represented by the general formula (103) is represented by the following general formula (104).
Formula _{(104): CH 2 = C} (R 41) (COOR 42)

  Preferred examples of such monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, (meth) acrylic acid. t-butyl, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth ) 3-hydroxypropyl acrylate, 2,3,4,5,6-pentahydroxyhexyl (meth) acrylate and 2,3,4,5-tetrahydroxypentyl (meth) acrylate, among others, methacryl Methyl acid is most preferably used. These may be used individually by 1 type, or may use 2 or more types together.

  The content of the unsaturated carboxylic acid alkyl ester unit relative to the (meth) acrylic polymer is preferably 50 to 95% by mass, more preferably 55 to 90% by mass. A (meth) acrylic polymer having a glutaric anhydride unit and an unsaturated carboxylic acid alkyl ester unit is obtained by polymerizing a copolymer having an unsaturated carboxylic acid alkyl ester unit and an unsaturated carboxylic acid unit, for example. It can be obtained by cyclization.

As an unsaturated carboxylic acid unit, what is represented, for example by the following general formula (105) is preferable.
Formula _{(105): - [CH 2} -C (R 51) (COOH)] -
Here, R ⁵¹ represents hydrogen or an alkyl group having 1 to 5 carbon atoms.

Preferable specific examples of the monomer for deriving the unsaturated carboxylic acid unit include a compound represented by the following general formula (106) which is a monomer corresponding to the repeating unit represented by the general formula (105), and Examples thereof include maleic acid and a hydrolyzate of maleic anhydride, and acrylic acid and methacrylic acid are preferable, and methacrylic acid is more preferable in terms of excellent thermal stability.
Formula _{(106): CH 2 = C} (R 51) (COOH)

  These may be used individually by 1 type, or may use 2 or more types together. As described above, an acrylic thermoplastic copolymer having a glutaric anhydride unit and an unsaturated carboxylic acid alkyl ester-based unit is, for example, a copolymer having an unsaturated carboxylic acid alkyl ester-based unit and an unsaturated carboxylic acid unit. Since the polymer can be obtained by cyclization of the polymer, it may have an unsaturated carboxylic acid unit in its constituent unit.

  As content of the unsaturated carboxylic acid unit with respect to said (meth) acrylic-type polymer, 10 mass% or less is preferable, More preferably, it is 5 mass% or less. By setting the content to 10% by mass or less, it is possible to prevent a decrease in colorless transparency and retention stability.

  Moreover, the said (meth) acrylic-type polymer may have the other vinyl-type monomer unit which does not contain an aromatic ring in the range which does not impair the effect of this invention. Specific examples of other vinyl monomer units that do not contain an aromatic ring include the corresponding monomers: vinyl cyanide monomers such as acrylonitrile, methacrylonitrile, ethacrylonitrile; allyl glycidyl ether Maleic anhydride, itaconic anhydride; N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, acrylamide, methacrylamide, N-methylacrylamide, butoxymethylacrylamide, N-propylmethacrylamide; aminoethyl acrylate, acrylic Propylaminoethyl acid, dimethylaminoethyl methacrylate, ethylaminopropyl methacrylate, cyclohexylaminoethyl methacrylate; N-vinyldiethylamine, N-acetylvinylamine, allylamine, methallylamino , N- methyl-allyl amine; 2-isopropenyl - oxazoline, 2-vinyl - oxazoline, 2-acryloyl - oxazoline, and the like. These may be used alone or in combination of two or more.

  As content of the other vinyl-type monomer unit which does not contain an aromatic ring with respect to said (meth) acrylic-type polymer, 35 mass% or less is preferable.

  For vinyl monomer units containing an aromatic ring (N-phenylmaleimide, phenylaminoethyl methacrylate, p-glycidylstyrene, p-aminostyrene, 2-styryl-oxazoline, etc.), they have scratch resistance and weather resistance. Since there exists a tendency to reduce, it is preferable to keep it as 1 mass% or less as content with respect to the said (meth) acrylic-type polymer.

((Meth) acrylic polymer with glutarimide ring structure in the main chain)
The (meth) acrylic polymer having a glutarimide ring structure in the main chain (hereinafter also referred to as a glutarimide resin) has preferable characteristics in terms of optical properties and heat resistance by having a glutarimide ring structure in the main chain. Balance can be expressed. The (meth) acrylic polymer having a glutarimide ring structure in the main chain is at least the following general formula (107):

Wherein R ³⁰¹ , R ³⁰² and R ³⁰³ are independently hydrogen or an unsubstituted or substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group or an aryl group. It is preferable to contain a glutarimide resin having 20% by mass or more.

As preferred glutarimide units constituting the glutarimide resin used in the present invention, R ³⁰¹ and R ³⁰² are hydrogen or a methyl group, and R ³⁰³ is a methyl group or a cyclohexyl group. The glutarimide unit may be a single type, or may include a plurality of types in which R ³⁰¹ , R ³⁰² , and R ³⁰³ are different.

  A preferred second structural unit constituting the glutarimide resin used in the present invention is a unit composed of an acrylate ester or a methacrylate ester. Preferable acrylic acid ester or methacrylic acid ester structural unit includes methyl acrylate, ethyl acrylate, methyl methacrylate, methyl methacrylate and the like. Another preferred imidizable unit includes N-alkyl methacrylamide such as N-methyl methacrylamide and N-ethyl methacrylamide. These second structural units may be of a single type or may include a plurality of types.

  The content of the glutarimide unit represented by the general formula (107) in the glutarimide resin is 20% by mass or more based on the total repeating unit of the glutarimide resin. The preferable content of the glutarimide unit is 20% by mass to 95% by mass, more preferably 50 to 90% by mass, and still more preferably 60 to 80% by mass. When a glutarimide unit is smaller than this range, the heat resistance of the film obtained may be insufficient or transparency may be impaired. On the other hand, if it exceeds this range, the heat resistance is unnecessarily increased and it becomes difficult to form a film, the mechanical strength of the resulting film becomes extremely brittle, and the transparency may be impaired.

  The glutarimide-based resin may be further copolymerized with a third structural unit as necessary. Preferred examples of the third structural unit include styrene monomers such as styrene, substituted styrene and α-methylstyrene, acrylic monomers such as butyl acrylate, and nitrile monomers such as acrylonitrile and methacrylonitrile. , A structural unit obtained by copolymerizing maleimide monomers such as maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide can be used. These may be directly copolymerized with the glutarimide unit and the imidizable unit in the glutarimide resin, and graft copolymerized with the resin having the glutarimide unit and the imidizable unit. It may be polymerized. When the third component is added, the content in the glutarimide resin is preferably 5 mol% or more and 30 mol% or less based on the total repeating units in the glutarimide resin.

  The glutarimide resin is described in US Pat. No. 3,284,425, US Pat. No. 4,246,374, JP-A-2-153904, and the like, and is obtained by using methyl methacrylate as a main raw material as a resin having an imidizable unit. It can be obtained by using a resin and imidizing the resin having an imidizable unit with ammonia or a substituted amine. When obtaining a glutarimide resin, a unit composed of acrylic acid, methacrylic acid, or an anhydride thereof may be introduced into the glutarimide resin as a reaction by-product. The presence of such a structural unit, particularly an acid anhydride, is not preferable because it reduces the total light transmittance and haze of the obtained film of the present invention. The acrylic acid or methacrylic acid content is 0.5 milliequivalent or less per gram of resin, preferably 0.3 milliequivalent or less, more preferably 0.1 milliequivalent or less. In addition, as seen in JP-A No. 02-153904, it is also possible to obtain a glutarimide resin by imidization using a resin mainly composed of N-methylacrylamide and methacrylic acid methyl ester.

The glutarimide resin preferably has a weight average molecular weight of 1 × 10 ⁴ to 5 × 10 ⁵ .

<Ultraviolet absorber>
The ultraviolet absorber preferably used for the base film will be described. The optical film of the present invention including the base film is used for a polarizing plate, a liquid crystal display member, or the like. From the viewpoint of preventing deterioration of the polarizing plate or the liquid crystal, an ultraviolet absorber is preferably used. As the ultraviolet absorber, those excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less and having little absorption of visible light having a wavelength of 400 nm or more are preferably used from the viewpoint of good liquid crystal display properties. Only one type of ultraviolet absorber may be used, or two or more types may be used in combination. For example, the ultraviolet absorber as described in Unexamined-Japanese-Patent No. 2001-72782 and Special Table 2002-543265 is mentioned. Specific examples of the ultraviolet absorber include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like.

  Among them, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) benzotriazole, 2- (2′- Hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2 '-Hydroxy-3'-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3 -Tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2'-hydroxy-3'-tert-butyl-5'-methyl) Enyl) -5-chlorobenzotriazole, 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis (2-methoxy-4-hydroxy) -5-benzoylphenylmethane), (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2 (2 '-Hydroxy-3', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, (2 (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) -5-chlorobenzo Triazole, 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1 , 3,5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert- Butyl-4-hydroxyphenyl) propionate, N, N′-hexamethylenebis (3,5-di-tert-butyl-4- Hydroxy-hydrocinnamide), 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-tert-butyl) -4-hydroxybenzyl) -isocyanurate and the like. In particular, (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2 (2′-hydroxy-3 ′, 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, (2 (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) -5-chlorobenzotriazole, 2,6-di -Tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-tert-butyl -5-methyl-4-hydroxyphenyl) propionate], for example, N, N'-bis [3- (3,5-di-tert-butyl-4 Hydroxyphenyl) may be used in combination with phosphorus-based processing stabilizer such as metal hydrazine systems such as propionyl] hydrazine deactivator and tris (2,4-di -tert- butylphenyl) phosphite.

  An ultraviolet absorber can also be introduce | transduced into resin as a structural unit which has an ultraviolet absorptivity. For example, a benzotriazole derivative, a triazine derivative or a benzophenone derivative into which a polymerizable group is introduced. The polymerizable group to be introduced can be appropriately selected according to the structural unit of the resin.

  Specific examples of the monomer having ultraviolet absorbing ability include 2- (2′-hydroxy-5′-methacryloyloxy) ethylphenyl-2H-benzotriazole (manufactured by Otsuka Chemical Co., Ltd., trade name RUVA-93), 2- (2 '-Hydroxy-5'-methacryloyloxy) phenyl-2H-benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methacryloyloxy) phenyl-2H-benzotriazole.

(Other additives)
Additives such as a matting agent, a retardation developer, a plasticizer, an ultraviolet absorber, a deterioration preventing agent, a release agent, an infrared absorber, a wavelength dispersion adjusting agent, and a moisture permeability reducing compound may be added to the base film. They can be solid or oily. That is, the melting point and boiling point are not particularly limited. For example, mixing of ultraviolet absorbing material at 20 ° C. or lower and 20 ° C. or higher, and similarly mixing of a plasticizer is described in, for example, JP-A-2001-151901. Furthermore, infrared absorbing dyes are described in, for example, JP-A No. 2001-194522. Moreover, the addition time may be added at any time in the dope preparation step, but may be added by adding an additive to the final preparation step of the dope preparation step. Furthermore, the amount of each material added is not particularly limited as long as the function is manifested. Moreover, when an optical film is formed from a multilayer, the kind and addition amount of the additive of each layer may differ. For example, it is described in Japanese Patent Application Laid-Open No. 2001-151902, and these are conventionally known techniques. For these details, materials described in detail on pages 16 to 22 in the Japan Institute of Invention Disclosure Technical Bulletin (Public Technical No. 2001-1745, published on March 15, 2001, Japan Institute of Invention) are preferably used.

<Moisture permeability reducing compound>
Of the other additives, the moisture permeability reducing compound is described in detail below. It is also preferable that the base film contains a moisture permeability reducing compound. A polymer having low moisture permeability due to the polymer alone has a low solubility in a solvent and has many problems in the production process. By reducing the moisture permeability by combining the polymer and the moisture permeability reducing compound, it becomes possible to achieve both low moisture permeability and solubility (manufacturability), and it is preferable to include a moisture permeability reducing compound.

  The moisture permeability reducing compound may have a structure including one or more aromatic rings. Hydrophobic properties can be imparted to the film by the aromatic ring, and moisture permeation and desorption can be suppressed.

  As the moisture permeability reducing compound contained in the base film, a compound represented by the following general formula (A) can be preferably used.

(In general formula (A), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ each independently represents a hydrogen atom or a substituent.)

In the general formula (A), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ each independently represents a hydrogen atom or a substituent. The aforementioned substituent T can be applied. Further, these substituents may be further substituted with another substituent, and the substituents may be condensed to form a ring structure.

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁸ and R ^{9 in the} general formula (A) are preferably hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, aryl groups, substituted or unsubstituted An 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, still more preferably a hydrogen atom, An alkyl group having 1 to 12 carbon atoms, particularly preferably a hydrogen atom or a methyl group, and most preferably a hydrogen atom.

R ² in the general formula (A) 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, a halogen atom, or more. Preferred are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted amino group having 0 to 20 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, and a hydroxy group. More preferably, it is a C1-C20 alkoxy group, Most preferably, it is a C1-C12 alkoxy group.

R ⁷ in the general formula (A) 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, a halogen atom, or more. Preferably, a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted amino group having 0 to 20 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, and a hydroxy group More preferably a hydrogen atom or an alkyl group having 1 to 20 carbon atoms (preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably a methyl group), particularly preferably a methyl group or a hydrogen atom. Is an atom.

  Although the preferable example of a compound represented by the said general formula (A) below is shown below, this invention is not limited to these specific examples.

As the moisture permeability reducing compound contained in the base film, a compound represented by the following general formula (B) can be preferably used.
General formula (B)

In the general formula ^{(B), R 12, R} 13, R 14, R 15, R 16, R 21, R 23, R 24, R 25, R 32, R 33, R 34, R 35, R 36 are, Each represents a hydrogen atom or a substituent, and the substituent T described below can be applied as the substituent. Further, in the general formula (B), R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ²¹ , R ²³ , R ²⁴ , R ²⁵ , R ³² , R ³³ , R ³⁴ , R ³⁵ and R ^At least one of ³⁶ is an amino group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group, a hydroxy group, a mercapto group, or a carboxyl group.

Examples of the substituent T include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms, such as a methyl group, an ethyl group, an isopropyl group, and tert-butyl. Group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 carbon atoms). To 12, particularly preferably 2 to 8 carbon atoms, such as vinyl group, allyl group, 2-butenyl group, and 3-pentenyl group), alkynyl group (preferably 2 to 20 carbon atoms, more preferably Has 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, and examples thereof include a propargyl group and a 3-pentynyl group.), Aryl (Preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include a phenyl group, a p-methylphenyl group, and a naphthyl group.), An amino group (Preferably has 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, and particularly preferably 0 to 6 carbon atoms. For example, amino group, methylamino group, dimethylamino group, diethylamino group, dibenzylamino group, etc. And an alkoxy group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, and a butoxy group. ), An aryloxy group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyl A xy group, a 2-naphthyloxy group, etc.), an acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms, such as an acetyl group, A benzoyl group, a formyl group, a pivaloyl group, etc.), an alkoxycarbonyl group (preferably having a carbon number of 2 to 20, more preferably a carbon number of 2 to 16, particularly preferably a carbon number of 2 to 12, such as methoxycarbonyl Group, an ethoxycarbonyl group, etc.), an aryloxycarbonyl group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, particularly preferably having 7 to 10 carbon atoms, such as a phenyloxycarbonyl group. An acyloxy group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, especially Preferably it is C2-C10, for example, an acetoxy group, a benzoyloxy group, etc. are mentioned. ), An acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include an acetylamino group and a benzoylamino group), alkoxycarbonyl. An amino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as a methoxycarbonylamino group), an aryloxycarbonylamino group (preferably Has 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as a phenyloxycarbonylamino group, and a sulfonylamino group (preferably 1 to 1 carbon atom). 20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms. Nylamino group, benzenesulfonylamino group, etc.), 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 group, methyl A sulfamoyl group, a dimethylsulfamoyl group, a phenylsulfamoyl group, etc.), a carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to carbon atoms). 12 and examples thereof include a carbamoyl group, a methylcarbamoyl group, a diethylcarbamoyl group, a phenylcarbamoyl group, etc.), an alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably carbon atoms). Examples thereof include methylthio group and ethylthio group. ), An arylthio group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as a phenylthio group), a sulfonyl group (preferably C1-C20, More preferably, it is C1-C16, Most preferably, it is C1-C12, For example, a mesyl group, a tosyl group, etc. are mentioned), a sulfinyl group (preferably C1-C20, More preferably, it is C1-C16, Most preferably, it is C1-C12, for example, a methanesulfinyl group, a benzenesulfinyl group, etc.), a ureido group (preferably C1-C20, more preferably carbon) The number is 1 to 16, particularly preferably 1 to 12, and examples thereof include a ureido group, a methylureido group, and a phenylureido group. ), A phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms, such as a diethylphosphoric acid amide group and a phenylphosphoric acid amide group. Hydroxy group, mercapto group, halogen atom (eg 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 Group, heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom, and a sulfur atom, specifically, for example, an imidazolyl group, a pyridyl group, and a quinolyl group. Group, furyl group, piperidyl group, morpholino group, benzoxazolyl group, benzimidazolyl group, benzthiazolyl group, etc. ), A silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms, and examples thereof include a trimethylsilyl group and a triphenylsilyl group. For example). Among these, an alkyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, and an aryloxy group are more preferable, and an alkyl group, an aryl group, and an alkoxy group are more preferable.
These substituents may be further substituted with a substituent T. Moreover, when there are two or more substituents, they may be the same or different. If possible, they may be linked together to form a ring.

Further, in the general formula ^{(B), R 12, R} 13, R 14, R 15, R 16, R 21, R 23, R 24, R 25, R 32, R 33, R 34, R 35, R 36 At least one of them is an amino group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group, a hydroxy group, a mercapto group, or a carboxyl group, more preferably an amino group or a hydroxy group. A hydroxy group is preferred. These groups may be substituted with a substituent. As the substituent in this case, the above-described substituent T can be applied, and the preferred range is also the same.

  Preferred examples of the compound represented by the general formula (B) are shown below, but the present invention is not limited to these specific examples.

As the moisture permeability reducing compound contained in the base film, a novolac compound can also be preferably used.
Although it does not specifically limit as a novolak type phenol resin used for this invention, Generally what reacted phenols and aldehydes using an acidic substance as a catalyst is used preferably. Although it does not specifically limit as phenols used as the raw material of a novolak-type phenol resin, For example, cresol, such as phenol, o-cresol, m-cresol, and p-cresol, 2,3-xylenol, 2,4-xylenol, 2, 5-xylenol, 2,6-xylenol, 3,4-xylenol, xylenol such as 3,5-xylenol, ethylphenol such as o-ethylphenol, m-ethylphenol, p-ethylphenol, isopropylphenol, butylphenol, p -Alkylphenols such as butylphenol such as tert-butylphenol, p-tert-amylphenol, p-octylphenol, p-nonylphenol, p-cumylphenol, fluorophenol, chlorophenol, bromophenol, Halogenated phenols such as dephenol, monovalent phenol substitutes such as p-phenylphenol, aminophenol, nitrophenol, dinitrophenol and trinitrophenol, and monovalent phenols such as 1-naphthol and 2-naphthol, resorcin And polyhydric phenols such as alkylresorcin, pyrogallol, catechol, alkylcatechol, hydroquinone, alkylhydroquinone, phloroglucin, bisphenol A, bisphenol F, bisphenol S, and dihydroxynaphthalene. Although these can be used individually or in combination of 2 or more types, generally phenol and cresol are often used.

  The moisture permeability reducing compound is preferably included in the base film in an amount of 10% by mass to 100% by mass with respect to the mass of the thermoplastic resin. More preferably, they are 15 mass% or more and 90 mass% or less, and 20 mass% or more and 80 mass% or less are still more preferable.

  The base film may contain rubber-like particles. Examples thereof include acrylic particles such as soft acrylic resin, acrylic rubber, and rubber-acrylic graft type core-shell polymer, or styrene-elastomer copolymer. Furthermore, additives that improve impact resistance and stress whitening resistance described in JP-B-60-17406, JP-B-3-39095 and the like are also preferably used.

In the said base film, when adding these additives, it is preferable that the total amount of an additive is 50 mass% or less with respect to a base film, and it is preferable that it is 30 mass% or less.
These additives improve the brittleness of the film and greatly improve the folding resistance test of the film (e.g., crack evaluation when bent 180 degrees).
In order to achieve low haze, the refractive index of the additive preferably has substantially the same refractive index as the base polymer, and the refractive index difference is preferably 0.5 or less, more preferably 0.3 or less. preferable.

(Base film thickness)
The film thickness of the substrate film is preferably 5 to 100 μm, more preferably 10 to 80 μm, particularly preferably 15 to 70 μm, and particularly preferably 20 to 60 μm. By controlling the film thickness within the above range, it is possible to reduce the unevenness of the panel due to the environment where the liquid crystal display device is placed after laminating the low moisture permeable layer, that is, the temperature and humidity change.

(Water vapor permeability of base film)
The moisture permeability of the base film is measured under the conditions of 40 ° C. and 90% relative humidity based on JIS Z-0208.
The moisture permeability of the base film is preferably 300 g / m ² / day or less, more preferably 250 g / m ² / day or less, still more preferably 200 g / m ² / day or less, It is particularly preferably 150 g / m ² / day or less. By controlling the moisture permeability of the base film within the above range, the liquid crystal display device equipped with the optical film (the optical film of the present invention) on which the low moisture permeable layer is mounted is subjected to normal temperature, high humidity, and high temperature and high humidity environment over time. In addition, warping of the liquid crystal cell and display unevenness during black display can be suppressed.

(Oxygen permeability coefficient of base film)
In order to reduce moisture permeability, it is preferable to suppress the diffusion of water in the film, that is, it is preferable to reduce the free volume of the film. In general, the free volume of the film correlates with the oxygen permeability coefficient of the film.
The oxygen permeability coefficient of the base film is preferably 100 cc · mm / (m ² · day · atm) or less, and more preferably 30 cc · mm / (m ² · day · atm) or less.
The oxygen permeability coefficient of the base film can be measured by the following method.

<Measurement method of oxygen permeability coefficient>
The oxygen permeation amount of the film is measured by attaching a test piece cut to a diameter of 1.5 cm through silicon grease thinly applied to an oxygen electrode (MODEL 3600, PFA manufactured by Orbis Fair Laboratories), and outputting oxygen reduction current in a steady state. The oxygen permeation amount was determined from the value.
Conversion of the output current value to the oxygen permeation amount was obtained by creating a calibration curve using a sample with a known permeation amount. The measurement was performed in an environment of 25 ° C. and 50% RH.

(Haze of base film)
The base film preferably has a total haze value of 2.00% or less. When the total haze value is 2.00% or less, the transparency of the film is high, and the contrast ratio and brightness of the liquid crystal display device are improved. The total haze value is more preferably 1.00% or less, further preferably 0.50% or less, particularly preferably 0.30% or less, and most preferably 0.20% or less. The lower the total haze value, the better the optical performance, but it is preferably 0.01% or more considering raw material selection, production control, and roll film handling.
The internal haze value of the substrate film is preferably 1.00% or less. By setting the internal haze value to 1.00% or less, the contrast ratio of the liquid crystal display device can be improved and excellent display characteristics can be realized. The internal haze value is more preferably 0.50% or less, further preferably 0.20% or less, particularly preferably 0.10% or less, and most preferably 0.05% or less. From the viewpoint of raw material selection, production control, etc., 0.01% or more is preferable.
In particular, the base film preferably has a total haze value of 0.30% or less and an internal haze value of 0.10% or less.
The total haze value and internal haze value are the types and addition amounts of film materials, selection of additives (particularly the particle size, refractive index, addition amount of matting agent particles), and further film production conditions (temperature at stretching, The stretching ratio can be adjusted.
In addition, the measurement of a haze can be measured according to JISK-6714 with a haze meter (HGM-2DP, Suga test machine) at 25 degreeC and 60% of relative humidity for the film sample 40 mm x 80 mm.

(Elastic modulus of base film)
The elastic modulus of the base film is preferably 1800 to 7000 MPa in the width direction (TD direction).
In the present invention, when the elastic modulus in the TD direction is within the above range, display unevenness at the time of black display after high humidity and high temperature and high humidity environment aging, transportability at the time of film production, end slit property and difficulty in breaking. It is preferable from the viewpoint of manufacturing suitability. If the TD elastic modulus is too small, display unevenness at the time of black display after high humidity and high temperature and high humidity environment is likely to occur, and there is a problem in manufacturing suitability. The elastic modulus is more preferably 1800 to 5000 MPa, and further preferably 1800 to 4000 MPa.
Moreover, 1800-4000 MPa is preferable and, as for the elasticity modulus of the conveyance direction (MD direction) of the said base film, it is more preferable that it is 1800-3000 MPa.
Here, the conveyance direction (longitudinal direction) of the film is the conveyance direction (MD direction) during film production, and the width direction is the direction (TD direction) perpendicular to the conveyance direction during film production.
The elastic modulus of the film depends on the type and amount of the thermoplastic resin used in the base film material, selection of additives (particularly, the particle size, refractive index, and amount of addition of the matting agent particles), and film production conditions (stretching). The magnification can be adjusted.
The elastic modulus is obtained, for example, by measuring a stress at 0.5% elongation at a tensile rate of 10% / min in an atmosphere of 23 ° C. and 70 RH% using a universal tensile tester “STM T50BP” manufactured by Toyo Baldwin Co., Ltd. be able to.

(Glass transition temperature Tg of base film)
The glass transition temperature Tg of the base film is preferably 100 ° C. or higher and 200 ° C. or lower, more preferably 100 ° C. or higher and 150 ° C. or lower, from the viewpoints of production suitability and heat resistance.
The glass transition temperature is a temperature at which the base line derived from the glass transition of the film starts to change and a temperature at which it returns to the base line again when measured at a heating rate of 10 ° C./min using a differential scanning calorimeter (DSC). It can be calculated as an average value.
Moreover, the measurement of a glass transition temperature can also be calculated | required using the following dynamic viscoelasticity measuring apparatuses. A film sample (unstretched) 5 mm × 30 mm was conditioned at 25 ° C. and 60% RH for 2 hours or more, and then grasped with a dynamic viscoelasticity measuring device (Vibron: DVA-225 (produced by IT Measurement Control Co., Ltd.)) Measured at a distance of 20 mm, a temperature increase rate of 2 ° C./min, a measurement temperature range of 30 ° C. to 250 ° C., and a frequency of 1 Hz. The straight line 1 and the straight line when a straight line 1 is drawn in the solid region and a straight line 2 is drawn in the glass transition region, when the storage elastic modulus sometimes shifts from the solid region to the glass transition region. The intersection of 2 is the temperature at which the storage elastic modulus suddenly decreases and the film begins to soften when the temperature rises, and is the temperature at which the film begins to move to the glass transition region.

(Knoop hardness of the base film)
The polarizing plate protective film used for the outermost surface preferably has a high surface hardness. In that case, as a characteristic of the base film, it is preferable that the Knoop hardness is high. The Knoop hardness is preferably 100 N / mm ² or more, more preferably 150 N / mm ² or more.
The Knoop hardness of the base film can be measured by the following method.

<Measurement of surface hardness>
Using the “Fuscherscope H100Vp hardness tester” manufactured by Fischer Instruments Co., Ltd., the direction of the minor axis of the indenter is relative to the transport direction (longitudinal direction; test direction in the pencil hardness test) when the cellulose acylate film is formed. The surface of the sample fixed to the glass substrate was measured with a Knoop indenter arranged in parallel under a load time of 10 sec, a creep time of 5 sec, an unload time of 10 sec, and a maximum load of 100 mN. The hardness was calculated from the relationship between the contact area between the indenter and the sample obtained from the indentation depth and the maximum load, and the average value of these five points was defined as the surface hardness.

(Equilibrium moisture content of base film)
The water content (equilibrium water content) of the base film is 25, regardless of the film thickness, so as not to impair the adhesiveness with water-soluble thermoplastics such as polyvinyl alcohol when used as a protective film for a polarizing plate. It is preferable that the moisture content in 0 degreeC and 80% of relative humidity is 0-4 mass%. It is more preferably 0 to 2.5% by mass, and still more preferably 0 to 1.5% by mass. If the equilibrium moisture content is 4% by mass or less, the dependence of retardation on humidity changes does not become too large, and the display unevenness of the liquid crystal display device during black display after normal temperature, high humidity, and high temperature and high humidity environments is suppressed. This is also preferable.
The moisture content was measured by measuring a film sample 7 mm × 35 mm by a Karl Fischer method using a moisture measuring device and sample drying apparatuses “CA-03” and “VA-05” (both manufactured by Mitsubishi Chemical Corporation). It can be calculated by dividing the amount of water (g) by the sample mass (g).

(Dimensional change of base film)
The dimensional stability of the base film is as follows: dimensional change rate after standing for 24 hours under conditions of 60 ° C. and 90% relative humidity (high humidity), and 80 ° C., DRY environment (relative humidity 5% or less) ) When it is allowed to stand for 24 hours under the above conditions (high temperature), it is preferable that the dimensional change rate is 0.5% or less. More preferably, it is 0.3% or less, More preferably, it is 0.15% or less.

(Photoelastic coefficient of base film)
When the optical film of the present invention is used as a protective film for a polarizing plate, birefringence (Re, Rth) may change due to stress caused by the contraction of the polarizer. Although the change in birefringence accompanying such stress can be measured as a photoelastic coefficient, the elastic modulus of the base film is preferably 15 Br or less, more preferably −3 to 12 Br, and more preferably 0 to 11 Br. More preferably it is.

<Method for producing base film>
Hereinafter, a manufacturing method for forming a thermoplastic resin film mainly composed of a (meth) acrylic polymer used in the present invention will be described in detail.
In order to form a base film using a (meth) acrylic polymer as a main component, for example, after pre-blending the film raw material with a conventionally known mixer such as an omni mixer, the resulting mixture is extrusion kneaded. To do. In this case, the mixer used for extrusion kneading is not particularly limited. For example, a conventionally known mixer such as an extruder such as a single screw extruder or a twin screw extruder or a pressure kneader can be used. .

  Examples of the film forming method include conventionally known film forming methods such as a solution casting method (solution casting method), a melt extrusion method, a calendar method, and a compression molding method. Of these film forming methods, the melt extrusion method is particularly suitable.

  Examples of the melt extrusion method include a T-die method and an inflation method, and the molding temperature at that time may be appropriately adjusted according to the glass transition temperature of the film raw material, and is not particularly limited. For example, it is preferably 150 ° C to 350 ° C, more preferably 200 ° C to 300 ° C.

  When forming a film by the T-die method, a roll-shaped film can be obtained by attaching a T-die to the tip of a known single-screw extruder or twin-screw extruder and winding the film extruded into a film. it can. At this time, it is possible to perform uniaxial stretching by appropriately adjusting the temperature of the take-up roll and adding stretching in the extrusion direction. Further, simultaneous biaxial stretching, sequential biaxial stretching, and the like can be performed by stretching the film in a direction perpendicular to the extrusion direction.

  The base film having the (meth) acrylic polymer as the main component may be either an unstretched film or a stretched film. In the case of a stretched film, either a uniaxially stretched film or a biaxially stretched film may be used. When it is a biaxially stretched film, either a simultaneous biaxially stretched film or a sequential biaxially stretched film may be used. In the case of biaxial stretching, the mechanical strength is improved and the film performance is improved. When the (meth) acrylic polymer is a (meth) acrylic polymer having a cyclic structure in the main chain, mixing with other thermoplastic resins increases the retardation even when stretched. It is possible to obtain a film that can be suppressed and retains optical isotropy.

  The stretching temperature is preferably in the vicinity of the glass transition temperature of the (meth) acrylic polymer that is the film raw material, specifically, preferably (glass transition temperature-30 ° C) to (glass transition temperature + 100 ° C), More preferably, it is within the range of (glass transition temperature−20 ° C.) to (glass transition temperature + 80 ° C.). If the stretching temperature is less than (glass transition temperature-30 ° C.), a sufficient stretching ratio may not be obtained. Conversely, when the stretching temperature exceeds (glass transition temperature + 100 ° C.), the flow of the (meth) acrylic polymer may occur, and stable stretching may not be performed.

  The draw ratio is preferably 1.1 to 25 times, more preferably 5.0 to 20 times in terms of area ratio, and particularly preferably 8 to 15 times. If the draw ratio is less than 1.1 times, the toughness accompanying the drawing may not be improved. On the other hand, when the draw ratio exceeds 25 times, the effect of increasing the draw ratio may not be recognized. Moreover, when the draw ratio is 5 times or more, moisture permeability may be lowered in addition to improvement of toughness, which is more preferable in the present invention.

  The stretching speed is unidirectional, preferably 10 to 20,000% / min, more preferably 100 to 10,000% / min. When the stretching speed is less than 10% / min, it takes time to obtain a sufficient stretching ratio, and the production cost may increase. On the contrary, when the stretching speed exceeds 20,000% / min, the stretched film may be broken.

  In addition, the base film obtained by using the (meth) acrylic polymer as a main component can be subjected to a heat treatment (annealing) or the like after the stretching treatment in order to stabilize its optical isotropy and mechanical properties. . The conditions for the heat treatment may be appropriately selected similarly to the conditions for the heat treatment performed on a conventionally known stretched film, and are not particularly limited.

  The thickness of the base film obtained with the (meth) acrylic polymer as a main component is preferably 5 μm to 200 μm, more preferably 10 μm to 100 μm. When the thickness is less than 5 μm, not only the strength of the film is lowered, but also when the durability test is performed by sticking to other parts, the crimp may be increased. On the other hand, when the thickness exceeds 200 μm, not only the transparency of the film is lowered, but also the moisture permeability is reduced, and when a water-based adhesive is used when sticking to other parts, water that is the solvent is used. The drying speed may be slow.

Furthermore, the base film achieves improved adhesion between the base film and the low moisture-permeable layer and other layers (for example, a polarizer, an undercoat layer, and a back layer) by optionally performing a surface treatment. be able to. For example, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be used. The glow discharge treatment here may be low-temperature plasma that occurs under a low pressure gas of 10 ^{−3 to} 20 Torr, and plasma treatment under atmospheric pressure is also preferred. A plasma-excitable gas is a gas that is plasma-excited under the above conditions, and includes chlorofluorocarbons such as argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, tetrafluoromethane, and mixtures thereof. It is done. Details of these are described in detail in pages 30 to 32 in the Japan Institute of Invention Disclosure Technical Bulletin (Public Technical Number 2001-1745, published on March 15, 2001, Japan Institute of Invention), and are preferably used in the present invention. be able to.

{Function layer}
The optical film of the present invention has a hard-coat layer and a pre-penetration layer containing a binder and a base acrylic resin contained in the hard-coat layer-forming composition, and further, on at least one surface, a functional layer May be laminated. The type of the functional layer is not particularly limited, but a hard coat layer, an antireflection layer (a layer having a adjusted refractive index such as a low refractive index layer, a medium refractive index layer, or a high refractive index layer), an antiglare layer, an antistatic layer, Examples thereof include an ultraviolet absorbing layer and an optically anisotropic layer.
The functional layer may be a single layer or a plurality of layers. The functional layer may be laminated on the surface of the base film provided with the hard coat layer and the osmotic layer, or may be the opposite surface. The method for laminating the functional layer is not particularly limited, and another functional layer may be provided on the optical film after the hard coat layer and the permeation layer are formed, or the hard coat layer and the functional layer are based. In the case of being arranged on another surface of the material film, a hard coat layer and a permeation layer can be formed on the opposite surface of the base film after forming the functional layer. When laminating a plurality of functional layers, one functional layer can be laminated on the hard coat layer, and the other functional layer can be laminated on the surface where the hard coat layer is not formed. Examples of functional layers are shown below.

(Low refractive index layer)
In the optical film of the present invention, a low refractive index layer may be provided on the hard coat layer directly or via another layer. In this case, the optical film of the present invention can function as an antireflection film.
In this case, the low refractive index layer preferably has a refractive index of 1.30 to 1.51. It is preferably 1.30 to 1.46, more preferably 1.32 to 1.38. Within the above range, the reflectance can be suppressed and the film strength can be maintained, which is preferable. The low refractive index layer can be formed by a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method, particularly a vacuum vapor deposition method or a sputtering method, which is a kind of physical vapor deposition method. It is preferable to use an all wet coating method using the composition for a low refractive index layer.

  The low refractive index layer is not particularly limited as long as it is a layer having the above refractive index range, but a known component can be used as a constituent component. Specifically, the fluorine-containing curability described in JP-A-2007-298974 can be used. A composition containing a resin and inorganic fine particles and a hollow silica fine particle-containing low refractive index coating described in JP-A Nos. 2002-317152, 2003-202406, and 2003-292831 are preferably used. be able to.

(Low moisture permeability layer)
The low moisture permeable layer refers to a layer that has a moisture permeability of 200 g / m ² / day or less and satisfies the formula (1) when laminated on a base film containing a thermoplastic resin. .
Formula (1) A / B <= 0.9
(In Formula (1), A represents the moisture permeability of the optical film which laminated | stacked the said low moisture-permeable layer on the base film containing the said thermoplastic resin, B represents the permeability | transmittance of the optical film before laminating | stacking a low moisture-permeable layer. (However, the moisture permeability is the value after 24 hours at 40 ° C. and 90% relative humidity by the method of JIS 0208.)

  In the optical film of the present invention, a low moisture permeable layer may be provided directly or via another layer on the hard coat layer or on the substrate opposite to the hard coat layer. The low moisture permeability layer may be a single layer or a plurality of layers. The method for laminating the low moisture permeable layer is not particularly limited, but the low moisture permeable layer is formed as a co-cast with the base film, or the low moisture permeable layer is laminated on the base film by coating. The low moisture-permeable layer is preferably provided by being laminated on the base film by coating. That is, in the optical film of the present invention, it is more preferable that the low moisture permeable layer is laminated on the base film by coating.

  The low moisture-permeable layer is not particularly limited as long as it reduces moisture permeability, but known components can be used as the constituent components, and specific examples include materials described in JP-A-2008-003580. .

(Optically anisotropic layer)
An optically anisotropic layer can also be provided on the optical film of the present invention. The optically anisotropic layer may be an optically anisotropic layer in which a film having a constant retardation is uniformly formed in the plane, and the direction of the slow axis and the magnitude of the retardation are different from each other. It may be an optically anisotropic layer having a pattern in which retardation regions are regularly arranged in a plane. The optically anisotropic layer is preferably formed on the surface of the base film on which the hard coat layer and the permeation layer are not formed.

  The optically anisotropic layer can be selected from materials and production conditions according to various uses, but in the present invention, an optically anisotropic layer using a polymerizable liquid crystalline compound is preferable. In that case, it is also a preferred embodiment that an alignment film is formed between the optically anisotropic layer and the substrate film in contact with the optically anisotropic layer.

  A preferred example having an optically anisotropic layer formed uniformly in the plane is an embodiment in which the optically anisotropic layer is a λ / 4 film, and is particularly useful as a member of an active 3D liquid crystal display device. As an aspect in which a λ / 4 film's anisotropy layer and a hard coat layer are laminated on opposite surfaces via a base film, they are described in JP2012-098772A and JP20121277982A. Such an embodiment can be preferably used in the optical film of the present invention.

  On the other hand, as a preferable example of the optically anisotropic layer in which a pattern is formed, a pattern type λ / 4 film is exemplified, and the embodiments described in Japanese Patent Nos. 4825934 and 4887463 are applied to the optical film of the present invention. It can be preferably used.

{Characteristics of optical film}
(Optical film thickness)
5-100 micrometers is preferable, as for the film thickness (total film thickness after laminating a osmosis | permeation layer and a hard-coat layer on a base film) of the optical film of this invention, 10-80 micrometers is more preferable, and 15-75 micrometers is especially preferable.

(Film thickness of each layer)
The thickness of the hard coat layer is preferably 1 μm or more, more preferably 1 μm to 20 μm, still more preferably 3 μm to 15 μm, and most preferably 5 μm to 10 μm. By setting it as the said range, surface hardness and antistatic property can be made compatible. Moreover, it is preferable that the ratio of the hard-coat layer film thickness with respect to the sum total of the film thickness of a hard-coat layer and a osmosis | permeation layer is 10%-90%, and 20%-80% are more preferable.

  The thickness of the osmotic layer is preferably 1 μm or more, more preferably 1 μm to 20 μm, still more preferably 3 μm to 18 μm, and most preferably 5 μm to 10 μm. By setting it as the said range, physical strength and antistatic property can be made compatible, and failures, such as a cloudiness of a film | membrane, can also be suppressed.

The film thickness of each layer can be measured, for example, by a cross-sectional SEM. When the optical film is cut with a microtome, the cross section is cut out and stained with osmium tetroxide, and then the surface is cut out again and the cross section SEM observation, the hard coat layer containing the quaternary ammonium salt polymer is brightly dyed and contains this The infiltration layer that cannot be observed is observed dark. Furthermore, among the monomers that have penetrated into the permeation layer, monomers that have penetrated deep into the base material do not have a large amount of diffusion, and are often blocked by the polymer chain of the base material and cannot completely complete the photopolymerization reaction. Since these monomers are dyed, the interface between the permeation layer and the substrate is observed brightly.
Thus, since contrast is given and the interface of the hard coat layer / penetrating layer and the penetrating layer / base material can be observed, the film thickness of each of the hard coat layer and the penetrating layer can be measured.
As another method, when the optical film is cut with a microtome, a cross section is cut out and analyzed with a time-of-flight secondary ion mass spectrometer (TOF-SIMS), both the base material component and the hard coat layer component are detected. It is also possible to detect a portion as a penetrating layer and a region where only a hard coat layer component is detected as a hard coat layer. The ratio of the film thickness of each layer can be measured from the cross-sectional information of TOF-SIMS, and the film thickness of each layer can be known by simultaneously measuring the total film thickness of the film.

(Water vapor transmission rate of optical film)
The moisture permeability of the optical film of the present invention is measured under the conditions of 40 ° C. and 90% relative humidity based on JIS Z-0208.
The moisture permeability of the optical film of the present invention is preferably 200 g / m ² / day or less, more preferably 120 g / m ² / day or less, and even more preferably 50 g / m ² / day or less. . If the water vapor transmission rate is 200 g / m ² / day or less, warpage of the liquid crystal cell and display unevenness during black display after the normal temperature, high humidity, and high temperature and high humidity environment of the liquid crystal display device can be suppressed.

(Surface hardness of optical film)
The surface hardness of the optical film of the present invention is preferably H or more, more preferably 2H or more, and most preferably 3H or more in the pencil hardness test described in JIS K5400. 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.

(Conductivity of optical film)
The common logarithm value (Log SR) of the surface resistivity SR (Ω / sq) of the optical film of the present invention is preferably as low as possible from the viewpoint of antistatic properties, and is preferably 12 or less in an environment of 25 ° C. and 60%. Is 5-11 or less, more preferably 6-10. By setting the surface resistivity within the above range, excellent dust resistance can be imparted.

  The transmittance of the optical film of the present invention is preferably 80% or more, more preferably 85% or more, and most preferably 90% or more.

<Method for producing optical film>
The optical film of the present invention can be formed by the following method, but is not limited to this method.
First, the above-mentioned composition for forming a hard coat layer is prepared. Next, the composition is applied onto a transparent support by 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, a die coating method, etc. The layer formed from the composition for forming a hard coat layer is cured by irradiation, whereby the hard coat layer and the permeation layer can be formed simultaneously. A micro gravure coating method, a wire bar coating method, and a die coating method (see US Pat. No. 2,681,294 and JP-A-2006-122889) are more preferable, and a die coating method is particularly preferable.

  In this way, the optical film of the present invention is obtained. Further, other layers as described above can be provided as necessary. In the method for producing an optical film of the present invention, a plurality of layers may be applied simultaneously or sequentially.

[Polarizer]
The polarizing plate of the present invention includes a polarizer and at least one optical film of the present invention as a protective film for the polarizer.
The optical film of the present invention can be used as a protective film for a polarizing plate. When using as a protective film for polarizing plates, the production method of a polarizing plate is not specifically limited, It can produce by a general method. There is a method in which the obtained optical film is treated with an alkali and bonded to both sides of a polarizer prepared by immersing and stretching a polyvinyl alcohol film in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. Instead of alkali treatment, easy adhesion processing as described in JP-A-6-94915 and JP-A-6-118232 may be performed. Further, the surface treatment as described above may be performed. The bonding surface of the optical film with the polarizer may be a surface laminated with a low moisture permeable layer or a surface not laminated with a low moisture permeable layer.
Examples of the adhesive used to bond the protective film treated surface and the polarizer include polyvinyl alcohol adhesives such as polyvinyl alcohol and polyvinyl butyral, vinyl latexes such as butyl acrylate, and the like.
The polarizing plate is composed of a polarizer and a protective film that protects both surfaces of the polarizer, and further includes a protective film bonded to one surface of the polarizing plate and a separate film bonded to the other surface. The protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection. In this case, the protect film is bonded for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal plate. Moreover, a separate film is used in order to cover the adhesive layer bonded to a liquid crystal plate, and is used for the surface side which bonds a polarizing plate to a liquid crystal plate.

[Liquid Crystal Display]
The liquid crystal display device of the present invention includes a liquid crystal cell and the polarizing plate of the present invention disposed in at least one of the liquid crystal cells, so that the optical film of the present invention contained in the polarizing plate is the outermost layer. It is arranged.

(General liquid crystal display device configuration)
The liquid crystal display device includes a liquid crystal cell having a liquid crystal supported between two electrode substrates, two polarizing plates disposed on both sides thereof, and, if necessary, between the liquid crystal cell and the polarizing plate. At least one optical compensation film is arranged.
The liquid crystal layer of the liquid crystal cell is usually formed by sealing liquid crystal in a space formed by sandwiching a spacer between two substrates. The transparent electrode layer is formed on the substrate as a transparent film containing a conductive substance. The liquid crystal cell may further be provided with a gas barrier layer, a hard coat layer, or an undercoat layer (undercoat layer) (used for adhesion of the transparent electrode layer). These layers are usually provided on the substrate. The substrate of the liquid crystal cell generally has a thickness of 50 μm to 2 mm.

In a liquid crystal display device, a substrate including a liquid crystal cell is usually disposed between two polarizing plates. The protective film for polarizing plates to which the optical film of the present invention is applied is a protective film for any of the two polarizing plates. Although it can be used, it is preferable to use as a protective film arrange | positioned outside a liquid crystal cell with respect to a polarizer among two protective films of each polarizing plate.
Of the two polarizing plates, it is particularly preferable to dispose the optical film of the present invention as a viewing-side protective film of the viewing-side polarizing plate.
Moreover, after arranging the optical film of the present invention as the protective film on the viewing side of the viewing side polarizing plate of the two polarizing plates, the present invention is also applied to the backlight side protective film of the backlight side polarizing plate. It is also a preferable aspect to dispose an optical film, suppress expansion and contraction of the polarizer contained in the two polarizing plates, and prevent warping of the panel.

(Types of liquid crystal display devices)
The film of the present invention can be used for liquid crystal cells in various display modes. TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-Ferroly Liquid Liquid Crystal), OCB (Optically QuantNW). Various display modes such as ECB (Electrically Controlled Birefringence) and HAN (Hybrid Aligned Nematic) have been proposed. In addition, a display mode in which the above display mode is oriented and divided has been proposed. The optical film of the present invention is effective in any display mode liquid crystal display device. Further, it is effective in any of a transmissive type, a reflective type, and a transflective liquid crystal display device.

  Hereinafter, the present invention will be specifically described based on examples. The materials, reagents, amounts and ratios of substances, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the present invention is not limited to the following examples.

[Production Example 1]
<Preparation of base film 1>
(Film made of acrylic resin with lactone ring unit structure in the main chain)
In a reaction vessel having an internal volume of 30 L equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introduction pipe, 8000 g of methyl methacrylate (MMA), 2000 g of methyl 2- (hydroxymethyl) acrylate (MHMA) and 10000 g of toluene as a polymerization solvent Was heated up to 105 ° C. while passing nitrogen through it. When the reflux accompanying the temperature rise began, 10.0 g of t-amylperoxyisonononanoate was added as a polymerization initiator, and a solution comprising 20.0 g of t-amylperoxyisonononanoate and 100 g of toluene was added. While dropping over time, solution polymerization was allowed to proceed under reflux at about 105 to 110 ° C., and further aging was performed for 4 hours. The polymerization reaction rate was 96.6%, and the content (mass ratio) of MHMA in the obtained polymer was 20.0%.

  Next, 10 g of stearyl phosphate / distearyl phosphate mixture (Phoslex A-18, manufactured by Sakai Chemical Industry Co., Ltd.) as a cyclization catalyst is added to the resulting polymerization solution, and the mixture is refluxed at about 80 to 100 ° C. for 5 hours. The cyclization condensation reaction was allowed to proceed.

  Next, the obtained polymerization solution was subjected to a barrel type screw twin screw extruder having a barrel temperature of 260 ° C., a rotation speed of 100 rpm, a degree of vacuum of 13.3 to 400 hPa (10 to 300 mmHg), a rear vent number of 1, and a forevent number of 4. (Φ = 29.75 mm, L / D = 30) was introduced at a treatment rate of 2.0 kg / hour in terms of resin amount, and cyclization condensation reaction and devolatilization were performed in the extruder. Next, after completion of devolatilization, the resin in the molten state left in the extruder is discharged from the tip of the extruder, pelletized by a pelletizer, and transparent pellets made of an acrylic resin having a lactone ring structure in the main chain A was obtained. The weight average molecular weight of this resin is 148,000, the melt flow rate (based on JIS K7120, the test temperature is 240 ° C., the load is 10 kg, the same applies to the following production examples) is 11.0 g / 10 min, glass transition The temperature was 130 ° C.

  Next, the obtained pellets and AS resin (made by Toyo Styrene, trade name: Toyo AS AS20) are kneaded using a single screw extruder (φ = 30 mm) at a mass ratio of pellet / AS resin = 90/10. As a result, a transparent pellet B having a glass transition temperature of 127 ° C. was obtained.

  The resin composition pellet B produced above was melt extruded from a coat hanger type T die using a twin screw extruder to produce a resin film having a thickness of about 160 μm.

  Next, the obtained unstretched resin film is simultaneously biaxially stretched by 2.0 times in the longitudinal direction and 2.0 times in the transverse direction (stretching ratio is 4 times by area ratio), thereby forming a transparent plastic film. A substrate was prepared. The biaxially stretchable film thus obtained had a thickness of 40 μm and a total light transmittance of 92%.

[Production Example 2]
<Preparation of base film 2>
(Film made of acrylic resin with glutaric anhydride unit structure in the main chain)
Using 100 parts by mass of methyl methacrylate-styrene copolymer (MS) resin (composition is 80 mol%: 20 mol%) and 20 parts by mass of monomethylamine (Mitsubishi Gas Chemical Co., Ltd.) as an imidizing agent, A resin was produced.

  The used extruder is a meshing type co-rotating twin screw extruder having L / D = 90 and a diameter of 40 mm. Nitrogen, which is an inert gas, was flowed from the hopper into the extruder at a flow rate of 200 ml / min. The set temperature of the reaction zone of the extruder (between the primary amine addition port and the vent port) was 270 ° C., and the screw rotation speed was 200 rpm. A raw material resin dried at 110 ° C. for 8 hours from a hopper was supplied at 20 kg / hr. After the resin was melted and filled by a kneading block, 20 parts by mass of monomethylamine (4 kg / hr) was supplied from the nozzle to the raw material resin. ) Was injected. A reverse flight was placed at the end of the reaction zone (before the vent port) to fill the resin. By-products and excess monomethylamine after the reaction were removed by reducing the pressure at the vent port to -0.092 MPa. Resin that came out as a strand from a die provided at the exit of the extruder was cooled in a water tank and then pelletized with a pelletizer to obtain pellet C.

  Using the pellet C, a transparent plastic film substrate was produced in the same manner as in Production Example 1. The biaxially stretchable film thus obtained had a thickness of 40 μm and a total light transmittance of 91%.

[Production Example 3]
<Preparation of base film 3>
(Film made of acrylic resin with lactone ring unit structure in the main chain)
In a reaction vessel having an internal volume of 30 L equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introduction pipe, 41.5 parts of methyl methacrylate (MMA) and 6 parts of methyl 2- (hydroxymethyl) acrylate (MHMA) 2.5 parts of 2- [2′-hydroxy-5′-methacryloyloxy] ethylphenyl] -2H-benzotriazole (trade name: RUVA-93, manufactured by Otsuka Chemical), 50 parts of toluene as a polymerization solvent, 0 0.025 part of an antioxidant (manufactured by Asahi Denka Kogyo Co., Ltd., Adeka Stub 2112) and 0.025 part of n-dodecyl mercaptan were charged as a chain transfer agent, and the temperature was raised to 105 ° C. through nitrogen. When the reflux with the temperature increase started, 0.05 part of t-amyl peroxyisononanoate (manufactured by Arkema Yoshitomi, trade name: Luperox 570) was added as a polymerization initiator, and 0.10 part of t- While amyl peroxy isononanoate was added dropwise over 3 hours, solution polymerization was allowed to proceed under reflux at about 105 to 110 ° C., followed by further aging for 4 hours.

  Next, 0.05 part of 2-ethylhexyl phosphate (manufactured by Sakai Chemical Industry Co., Ltd., Phoslex A-8) is added to the resulting polymerization solution as a catalyst for the cyclization condensation reaction (cyclization catalyst). The cyclization condensation reaction was allowed to proceed for 2 hours under reflux at 0 ° C., and then the polymerization solution was heated for 30 minutes in an autoclave at 240 ° C. to further proceed the cyclization condensation reaction. Next, 0.94 parts of CGL777MPA (manufactured by Ciba Specialty Chemicals) was mixed with the polymerization solution after the reaction proceeded as an ultraviolet absorber.

  Next, the obtained polymerization solution was subjected to a barrel temperature of 240 ° C., a rotation speed of 100 rpm, a degree of vacuum of 13.3 to 400 hPa (10 to 300 mmHg), a rear vent number of 1 and a forevent number of 4 (first and Bent type screw twin screw extruder (Φ = 50.0mm, L) with leaf disk type polymer filter (filtration accuracy 5μ, filtration area 1.5m2) at the tip / D = 30) was introduced at a treatment rate of 45 kg / hr in terms of resin amount, and devolatilization was performed. At that time, a separately prepared mixed solution of antioxidant / cyclization catalyst deactivator was charged at a rate of 0.68 kg / hour from the back of the first vent, and ion-exchanged water was charged at 0.22 kg / hour. Each was fed from behind the third vent at a speed.

  In the mixed solution of antioxidant / cyclization catalyst deactivator, 50 parts of antioxidant (Sumitizer GS manufactured by Sumitomo Chemical Co., Ltd.) and 35 parts of zinc octylate (manufactured by Nippon Kagaku Sangyo Co., Ltd., Nikka Octix) Zinc (3.6%) was dissolved in 200 parts of toluene.

  Next, after completion of devolatilization, the resin in the hot melt state remaining in the extruder is discharged while being filtered through a polymer filter from the tip of the extruder, pelletized by a pelletizer, and has a lactone ring structure in the main chain A transparent resin composition pellet D containing an acrylic resin and an ultraviolet absorber was obtained. The weight average molecular weight of the resin was 145000, and the glass transition temperature (Tg) of the resin and the resin composition was 122 ° C.

  The pellet D was melt-extruded from a coat hanger type T die using a twin screw extruder to produce a resin film having a thickness of about 160 μm.

Next, the obtained unstretched resin film is simultaneously biaxially stretched by 2.0 times in the longitudinal direction and 2.0 times in the transverse direction (stretching ratio is 4 times by area ratio), thereby forming a transparent plastic film. A substrate was prepared.
When the physical properties of the biaxially stretchable resin film thus obtained were measured, the thickness was 40 mm, the haze (turbidity) was 0.3%, the glass transition temperature was 128 ° C., and the transmittance for light at 380 nm was The transmittance for light of 5.8% and 500 nm was 92.2%.

[Production Example 4]
<Preparation of base film 4>
(Highly stretched film made of acrylic resin with lactone ring unit structure in the main chain)
The pellet B produced in Production Example 1 was melt-extruded from a coat hanger type T die using a twin screw extruder to produce a resin film having a thickness of about 500 μm.

  Next, the obtained unstretched resin film is biaxially stretched 3.4 times in the longitudinal direction and 3.6 times in the transverse direction (stretching ratio is 12.2 times in terms of area ratio). A film substrate was prepared. The biaxially stretchable film thus obtained had a thickness of 40 μm, a total light transmittance of 92%, a haze of 0.3%, and a glass transition temperature of 127 ° C.

[Example 1]
<Production of optical film>
As shown below, an antistatic hard coat layer forming composition (coating solution) was prepared, an antistatic hard coat layer was formed on a transparent substrate, and an optical film sample No. 1-12 were produced.

(Synthesis of (a) ion conductive compound IP-1)
IP-1 (30% by mass) which is the same as Synthesis Example 2 of Japanese Patent No. 4600655 and is a quaternary ammonium base-containing polymer having an ethylene oxide chain as a compound corresponding to (A-2) of the patent document. Ethanol solution) was synthesized.

(Preparation of coating solution for hard coat layer)
Each component was added so that it might become the composition of the coating liquid A-1 for hard-coat layers of the following Table 1, The obtained composition was thrown into a mixing tank, it stirred, and the polypropylene filter with the hole diameter of 0.4 micrometer. To obtain a hard coat layer coating solution A-1 (non-volatile content: 60% by mass).

  In the same manner as hard coat layer coating liquid A-1, the components are mixed as shown in Table 1 below, dissolved in a solvent and adjusted so that the composition ratios shown in Table 1 are obtained. Liquids A-2 to A-4 were prepared. In Table 1, the content of each component other than the solvent was expressed as the ratio (mass%) of the solid content of each component to the nonvolatile content of the coating solution.

(Preparation of hard coat layer)
On the transparent base material produced in the manufacture example 1, the said coating liquid A-1 for hard-coat layers was apply | coated using the gravure coater. After drying at 60 ° C. for about 2 minutes, using a 160 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) while purging with nitrogen so that the atmosphere has an oxygen concentration of 1.0% by volume or less, the illuminance The coating layer is cured by irradiating with ultraviolet rays of 400 mW / cm ² and an irradiation amount of 150 mJ / cm ² to form an antistatic hard coat layer A-1 having a thickness of 10 μm. 1 was produced.

  In the same manner, the antistatic property is adjusted by using the coating liquids A-1 to A-6 for the antistatic hard coat layer on the transparent substrate prepared in Production Example 1, 2, or 3, respectively. Hard coat layers A-2 to A-12 were prepared, and optical film sample Nos. 2 to 13 were produced.

(Evaluation of optical film)
Various characteristics of the optical film were evaluated by the following methods. The results are shown in Table 2.

(1) Film thickness measurement The prepared sample was cut with a microtome, cut into a cross section, stained with a 3% osmium tetroxide aqueous solution overnight, and then the surface was cut out again and observed with a cross section SEM. In backscattered electron increase, in order from the substrate side, the entire layer observed dark from the linearly brightly stained part is the permeation layer, and the brightly observed layer above it is the hard coat layer, and the film thickness is respectively Measured length.

(2) Measurement of surface resistance value After placing the sample for 2 hours at 20 ° C. and 15% RH, measurement was performed using a super insulation resistance / microammeter TR8601 (manufactured by Advantest Co., Ltd.). (Log SR). The lower the log SR, the better the antistatic property, and in the present invention, it is preferably less than 11.0 from the viewpoint of suppressing dust on the display when used as a polarizing plate protective film.

(3) Prevention of dust adhesion The transparent support side of the optical film is attached to the CRT surface, and used for 24 hours in a room having 1 to ² million pieces of dust and tissue paper waste of 0.5 μm or more per 1 ft ³ (legislation foot). did. The number of adhering dust and tissue paper waste per 100 cm ^{2 of the} antireflection film was measured, and the average value of each result was evaluated as follows.
A: Less than 20 and almost no dust adheres B: 20 to less than 150 and small amount of dust adheres, but no problem C: 150 to less than 200, medium amount of waste adheres There is no significant problem D: More than 200 pieces, a lot of scraps adhere

(4) Pencil hardness evaluation The pencil hardness evaluation described in JIS K 5400 was performed. The optical film was conditioned at a temperature of 25 ° C. and a humidity of 60% RH for 2 hours, and then evaluated using a test pencil specified in JIS S 6006. In the present invention, it is preferably 2H or more.

(4) Moisture permeability (moisture permeability at 40 ° C and 90% relative humidity)
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 method described in is applied.
70 mmφ of optical film samples of each example and comparative example were conditioned at 40 ° C. and 90% relative humidity for 24 hours, respectively, and using a moisture permeable cup according to JIS Z-0208, moisture permeability = mass after humidity adjustment−control The amount of water per unit area (g / m ² ) was calculated by the mass before wetting and evaluated as follows. The moisture permeability value was not corrected with a blank cup without a hygroscopic agent.
A: 50 g / m ² or less A ′: greater than 50 g / m ² and 90 g / m ² or less B: greater than 90 g / m ² and 120 g / m ² or less C: greater than 120 g / m ²

In the said Table 1, content of each component other than a solvent was represented by the ratio (mass%) of solid content of each component with respect to the non volatile matter of a coating liquid.
Moreover, content of each solvent was represented by the ratio (mass%) of the mass of each solvent with respect to the total mass of all the solvents (volatile matter).
In Table 1, in Sample 15 using the composition A-15, the coating film remarkably repelled and a hard coat layer could not be formed.

The compounds used are shown below.
IP-2: A poly (3,4-ethylenedioxythiophene) -poly (styrenesulfonic acid) 1.0% solution of JP 2011-31501 A [Adjustment Example 4]. Solvent is MEK / acetone / water (0.05% water)
A-TMMT: Pentaerythritol tetraacrylate (Shin Nakamura Chemical Co., Ltd. NK Ester)
A-TMM-3L: A mixture of pentaerythritol triacrylate (content 55% by mass), pentaerythritol diacrylate, pentaerythritol monoacrylate (Shin-Nakamura Chemical Co., Ltd., NK ester)
A-400: Polyethylene glycol diacrylate (repetition number of ethylene oxide 9) (Shin-Nakamura Chemical Co., Ltd. NK ester)
Irg. 184: Photopolymerization initiator, Irgacure 184 (manufactured by Ciba Japan Co., Ltd.)
MEK: methyl ethyl ketone (boiling point 79.5 ° C.)
IP-1

As shown in Table 2, the optical film having a hard coat layer formed using the composition for forming a hard coat layer according to the present invention has an osmotic layer formed between the acrylic base material and the hard coat layer. It was confirmed that Furthermore, it was confirmed that the sample containing the conductive polymer had low surface resistance and good antistatic properties, and that dust was suppressed.
Comparison of sample 1 as an example and sample 5 as a comparative example shows that even if the total thickness of the hard coat layer and the permeation layer is the same, sample 1 has a lower surface resistance and antistatic properties. It turns out that it is excellent in. It is thought that the conductive polymer was concentrated in the hard coat layer, and the antistatic property was further improved. Furthermore, comparison between Sample 1 as an example and Sample 5 as a comparative example shows that the pencil hardness can be increased when the penetration layer is formed even if the film thickness of the hard coat layer is the same.
It was also confirmed that the samples of the examples were excellent in low moisture permeability. In particular, the moisture permeability of Sample 14 was A rank, which was particularly excellent.

  In addition, the following compound FP-13 (a fluorosurfactant dissolved in a methyl ethyl ketone solvent at a solid content concentration of 40% by mass) is used as a leveling agent in the composition for forming a hard coat layer. When an optical film was prepared in the same manner except that 0.05% by mass was added to the non-volatile content, the same result as above was obtained.

  Moreover, in the optical film of any Example, even if the total film thickness of the hard coat layer and the osmotic layer was changed from 2 μm to 20 μm, the same effect as the Example of the present invention was obtained.

  In addition, in any of the optical films of Examples, Optical Film No. in Examples of International Publication No. 2009/047924 is used instead of the substrate containing the acrylic resin of Production Examples 1 and 2 as a substrate. When the film having a layer thickness of 60 μm described in 1 was used, the same effect as in the example of the present invention was obtained. Furthermore, even when a film whose thickness is changed from 20 μm to 100 μm by appropriately adjusting the draw ratio of Production Examples 1 and 2 as a base material is adjusted to be thicker than 80 μm, the level of moisture permeability is adjusted to be thinner than 30 μm. In this case, the same effect was obtained except that the moisture permeability level was C.

  Furthermore, on the hard coat layer of the optical film of any of Examples, Example Sample No. The sample in which the antireflection layer is formed in the same manner as the method described in 29, or the sample in which the low moisture-permeable layer is formed in the same method as the coating layer described in Example 1 of Japanese Patent Application Laid-Open No. 2008-003580 is used. The same effect as in the example was obtained.

  Furthermore, on the hard coat layer of the optical film of any of Examples, Example Sample No. A sample in which an antireflection layer is formed in the same manner as the method described in No. 29, or a sample in which a low moisture-permeable layer is formed in the same manner as the coating layer described in Example 1 of JP-A-2008-003580, JP-A-2008-249901 In the sample in which the low-humidity layer was formed by the same method as the coating layer described in Example 2, the same effects as those of the example of the present invention were obtained except that the moisture permeability was B, A, and A ′, respectively. It was.

  A sample in which a low moisture-permeable layer is formed on the substrate opposite to the hard coat layer of the optical film of any example by the same method as the coating layer described in Example 1 of JP-A-2008-003580, Also in the sample in which the low-humidity layer was formed by the same method as the coating layer described in Example 2 of Kai 2008-249901, the same effects as in the example of the present invention except that the moisture permeability was A and A ′, respectively. was gotten.

(Panel evaluation)
<Preparation of polarizing plate>
1) Saponification of film Commercially available cellulose acylate film (Fujitack ZRD40, manufactured by Fuji Film Co., Ltd.) and optical film samples 1 and 10 in the examples were placed in a 1.5 mol / L NaOH aqueous solution (saponification solution) maintained at 55 ° C. 2), the film was washed with water, and then immersed in a 0.05 mol / L sulfuric acid aqueous solution at 25 ° C. for 30 seconds, and then passed through a washing bath for 30 seconds under running water. It was in a state. Then, draining with an air knife was repeated three times, and after dropping the water, the film was retained in a drying zone at 70 ° C. for 15 seconds and dried to produce a saponified film.

2) Production of Polarizer According to Example 1 of Japanese Patent Application Laid-Open No. 2001-141926, iodine was adsorbed to a stretched polyvinyl alcohol film to produce a polarizer having a thickness of 20 μm.

3) Bonding (production of polarizing plates 101, 110, 113)
After applying the corona treatment to one side of the polarizer produced as described above, the surface of the produced optical film samples 1, 10 and 13 on which the low moisture permeable layer is not laminated is pasted using an acrylic adhesive. Combined. The saponified commercially available cellulose acylate film ZRD40 was attached to the other side of the polarizer prepared above using a polyvinyl alcohol-based adhesive, dried at 70 ° C. for 10 minutes or more, and polarizing plates 101, 110, 113. Was made.
Under the present circumstances, it arrange | positioned so that the longitudinal direction of the roll of the produced polarizer and the longitudinal direction of the optical films 102-106 may become parallel. Moreover, it arrange | positioned so that the longitudinal direction of the roll of a polarizer and the longitudinal direction of the roll of the said cell roll acylate film ZRD40 may become parallel.

<Implementation to IPS panel>
The upper and lower polarizing plates of the IPS mode liquid crystal cell (manufactured by LGD, 42LS5600) were peeled off, and the polarizing plates of the above examples and comparative examples were attached so that the ZRD 40 was on the liquid crystal cell side. The crossed nicols were arranged so that the transmission axis of the upper polarizing plate was in the vertical direction and the transmission axis of the lower polarizing plate was in the horizontal direction.
The obtained liquid crystal display device was made into the liquid crystal display device of each Example and a comparative example.
In addition, the structure of the polarizing plate of each Example and a comparative example at the time of mounting to an IPS panel was described in following Table 2.

  The liquid crystal display device produced as described above was evaluated for black display unevenness after a high temperature and high humidity environment. The results are shown in Table 3 below.

(Black display unevenness after high temperature and high humidity environment)
After the liquid crystal display device was passed for 20 hours at 65 ° C. and a relative humidity of 90%, it was lit for 2 hours in an environment of 25 ° C. and a relative humidity of 60%, and then turned on to reduce the degree of color unevenness during black display. It observed visually and evaluated in three steps according to the following criteria.
A: Color unevenness was not observed.
B: Although weak color unevenness was observed in an area of 1/2 or less of the display surface, there is no problem.
C: Color unevenness is observed in an area exceeding 1/2 of the display surface, which is a problem.

  As shown in Table 3, it can be seen that the black display unevenness of the panel is weak and is at a good level even after the high temperature and high humidity environment.

Claims (10)

  An optical film having a hard coat layer on a thermoplastic substrate made of an acrylic resin, the binder and the base contained in the composition for forming a hard coat layer between the thermoplastic substrate and the hard coat layer An optical film provided with a permeation layer containing an acrylic resin as a material.   The film thickness of the hard coat layer is 1 μm or more, and the film thickness of the hard coat layer with respect to the total film thickness of the hard coat layer and the permeation layer is 10% or more and 90% or less. 1. The optical film as described in 1.   The optical film according to claim 1 or 2, wherein the composition for forming a hard coat layer for forming the hard coat layer contains (a) a polymer component.   The optical film according to claim 1, wherein the polymer component (a) is a conductive polymer.   The composition for forming a hard coat layer further contains (b) a monomer having two or more unsaturated double bonds in the same molecule, (c) a photopolymerization initiator, and (d) an organic solvent. The optical film according to any one of claims 1 to 4.   The optical film according to any one of claims 1 to 5, wherein the SP value of the monomer (b) having two or more polymerizable groups in the same molecule is 17 to 30. The acrylic resin of the thermoplastic substrate is a lactone ring unit represented by the following formula (101),

(Wherein R ¹¹¹ , R ¹¹² and R ¹¹³ each independently represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom.)
Or a glutaric anhydride unit structure represented by the following formula (102)

(In the formula, R ³¹ and R ³² each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom.)
The optical film according to claim 1, comprising:   A polarizing plate comprising at least one polarizer and the optical film according to any one of claims 1 to 7 as a protective film for the polarizer.   A liquid crystal display device comprising: a liquid crystal cell; and the polarizing plate according to claim 8 disposed in at least one of the liquid crystal cells, wherein the optical film is disposed as an outermost layer.   A method for producing an optical film having a hard coat layer on a thermoplastic substrate made of an acrylic resin, wherein the thermoplastic substrate is formed by applying a composition for forming a hard coat layer on the thermoplastic substrate. A penetrating layer containing a binder contained in the composition for forming a hard coat layer and a base acrylic resin is formed between the hard coat layer and the hard coat layer.