JP2005206638A - Optical film and polarizing plate and picture display unit using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film which has a high planar homogeneity, especially an optical film which has a high planar homogeneity and an optical anisotropy and has no influence on its optical performance such a visibility angle, and a polarizing plate, a liquid crystal display device and a picture display unit in which the optical film is arranged. <P>SOLUTION: The optical film has optically functional layers on a transparent support. Here, at least one of the optically functional layers contains a fluorine-containing polymer having a specific structure. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical film containing a fluorine-containing copolymer, a polarizing plate, and a display device in which they are arranged.

  In recent years, development of materials using various coating methods has progressed. Particularly, a thin layer coating technique of several μm to several hundreds of nanometers is necessary for optical film, printing, photolithography, etc. The required coating accuracy is increasing with the increase in size and the speed of coating. Especially in the production of optical films, film thickness control is a very important point that affects optical performance, and it is necessary to increase productivity, so technology that can achieve high coating speed while maintaining high accuracy. The demand for is getting higher. However, while all wet coating using a solvent is very advantageous from the viewpoint of productivity, it is very difficult to keep the solvent dry immediately after coating, and surface unevenness tends to occur. The term “planar unevenness” as used herein refers to drying unevenness caused by a difference in solvent drying speed or thickness unevenness caused by drying air.

  It is known that it is effective to improve the leveling property in order to reduce unevenness during coating. As one means for improving the leveling property, a method of adding a surfactant to the coating composition has been proposed. In this method, the surface tension of the coating composition is reduced by the action of the surfactant to improve the wetting of the coating object, while the change in the surface tension during the coating formation process is reduced or reduced. This is based on a mechanism that improves thermal uniformity by preventing thermal convection (Non-patent Document 1). The optimum surface active species varies depending on the compatibility with the solvent, resin, and various additives in the target coating composition, but when coated with a solvent, it is soluble in the solvent and has the best surface tension reducing ability. It is effective to use a high fluorosurfactant.

Optical films in which liquid crystal compounds are highly oriented and fixed are being developed in various applications such as optical compensation films for liquid crystal display devices, brightness enhancement films, and optical correction films for projection display devices. The development of the device as an optical compensation film is remarkable. For example, Patent Documents 1 and 2 disclose optical compensation sheets in which an optically anisotropic layer formed from a discotic (disk-shaped) compound is coated on a transparent support. However, when the optical compensation sheet was mounted as a protective film on a polarizing plate of a large-sized liquid crystal display device, it was found that unevenness occurred on the panel, and improvement of the surface condition was a problem.
Patent Document 3 discloses a technique for improving unevenness by containing a leveling agent in a polymerizable liquid crystal, but it is effective only when the polymerizable liquid crystal is homogeneously aligned, including hybrid alignment. It was found that this is not applicable to the complicated orientation.
Japanese Patent Laid-Open No. 7-191217 European Patent 0911656A2 JP-A-11-148080 "Latest technology of coating additives", supervised by Haruo Kiryu, CMC, 2001

The purpose of the present invention is to
(1) To provide an optical film having high planar uniformity, in particular, an optical film having optical anisotropy having high planar uniformity without affecting optical performance such as viewing angle.
as well as,
(2) To provide a polarizing plate having such an optical film and an image display device.

As a result of careful examination of the structure and composition of the fluoroalkyl group in the fluorinated monomer that is a constituent of the fluorinated polymer surfactant, the present inventors have found that uneven drying caused during coating by using a fluorinated polymer having a specific structure. It was found that an optical film with high surface uniformity can be obtained without variation in wind and wind unevenness and without variation in optical performance and physical performance.
Furthermore, it has been found that a polarizing plate having high planar uniformity by using the optical film and an image display device using the polarizing plate can be obtained.

According to the present invention, an optical film, a polarizing plate, and an image display device having the following configuration are provided, and the above-described object of the present invention is achieved.
1. In an optical film having an optical functional layer on a transparent support, at least one layer of the optical functional layer includes a repeating unit derived from the following monomer (i) and a repeating unit derived from the following monomer (ii): An optical film comprising a fluorine-containing polymer whose content exceeds 50% by mass of the total polymerization units.
(I) A fluoroalkyl group-containing monomer represented by the following general formula [1].
(Ii) A fluoroalkyl group-containing monomer represented by the following general formula [2].
General formula [1]

General formula [2]

In the formula, R ¹ and R ² each independently represents a hydrogen atom, a methyl group or a halogen atom. L ¹ and L ² each independently represent a divalent group, and m and n each independently represent an integer of 1 to 12.
2. 2. The optical film as described in 1 above, wherein the fluoropolymer further has a repeating unit derived from the monomer (iii) below.
(Iii) A monomer copolymerizable with the monomers (i) and (ii).
3. 3. The optical film as described in 1 or 2 above, wherein the fluoroalkyl group-containing monomer represented by the general formula [1] is represented by the general formula [3].
General formula [3]

In the formula, X ¹ represents a divalent substituent represented by —O—, —S—, —N (R ³ ) —, and R ³ has a hydrogen atom or a substituent having 1 to 8 carbon atoms. Or an aryl group which may have a substituent having 6 to 20 carbon atoms, and p represents an integer of 1 to 8. R ¹ and m are the same as those in the general formula [1].
4). 4. The optical film as described in any one of 1 to 3, wherein the fluoroalkyl group-containing monomer represented by the general formula [2] is represented by the general formula [4].
General formula [4]

In the formula, X ² represents a divalent substituent represented by —O—, —S—, —N (R ³ ) —, and q represents an integer of 1 to 8. R ² and n are the same as those in general formula [2], and R ³ is the same as that in general formula [3].
5). 5. The optical film as described in any one of 1 to 4, wherein at least one of the optical functional layers containing the fluoropolymer is an optically anisotropic layer formed from a liquid crystal compound.
6). 6. The optical film as described in 5 above, wherein the liquid crystal compound is a discotic compound.
7). A polarizing plate comprising the optical film according to any one of 1 to 6 above.
8). A polarizing plate, wherein the optical film according to any one of 1 to 6 is used for one of two protective films of a polarizing film in the polarizing plate.
9. An image display device comprising the optical film according to any one of 1 to 6 above.

By including a fluorine-containing polymer having a CF ₂ H group and a CF ₃ group at the terminal, an optical film having no unevenness and excellent surface uniformity can be provided. Further, if the optical film of the present invention is used, optical compensation can be performed without unevenness. The polarizing plate and the image display device using the optical film of the present invention can display an image with high display quality without causing unevenness even in a large image display device.

The fluorine-containing polymer having a fluoroalkyl group according to the present invention will be described in detail.
The fluorine-containing polymer used in the present invention is a polymerization unit of a fluoroalkyl group-containing monomer represented by the general formula [1] (hereinafter sometimes abbreviated as “ω-H type fluorine-containing monomer”), and a general formula [2 ] A polymerization unit of a fluoroalkyl group-containing monomer represented by the formula (hereinafter sometimes abbreviated as “ω-F type fluorine-containing monomer”). For example, the ratio of the monomer is not particularly limited as long as it is a polymer composed of the monomer represented by the general formula [1] and the monomer represented by the general formula [2], but from the viewpoint of solubility and coatability, the general formula The content of the ω-H type fluorine-containing monomer represented by [1] exceeds 70% by mass, preferably 80% by mass or more, more preferably 90% by mass or more, based on the total polymerization units constituting the fluoropolymer. It is.

In the general formula [1], R ¹ represents a hydrogen atom, a methyl group or a halogen atom, more preferably a hydrogen atom or a methyl group. L ¹ represents a divalent linking group, m represents an integer of 1 to 12, more preferably 2 to 10, still more preferably 4 to 8, and most preferably 4, 6 or 8.
Further, two or more kinds of ω-H type fluorine-containing monomers represented by the general formula [1] may be contained in the fluorine-containing polymer as structural units.

In the general formula [2], R ² represents a hydrogen atom, a methyl group or a halogen atom, and more preferably a hydrogen atom or a methyl group. L ² represents a divalent linking group, n represents an integer of 1 to 12, more preferably 2 to 10, still more preferably 4 to 8, and most preferably 4, 6 or 8.
Further, two or more kinds of ω-F type fluorine-containing monomers represented by the general formula [2] may be contained in the fluorine-containing polymer as structural units.

The fluorine-containing polymer includes a ω-H type fluorine-containing monomer represented by the general formula [1], a ω-F type fluorine-containing monomer represented by the general formula [2], and a monomer copolymerizable therewith. It is also preferable. For example, in the case of a polymer comprising a ω-H type fluorine-containing monomer represented by the general formula [1], a ω-F type fluorine-containing monomer represented by the general formula [2], and a copolymerizable monomer, From the viewpoints of coating properties and coatability, the total content of the ω-H type fluorinated monomer represented by the general formula [1] and the content of the ω-F type fluorinated monomer represented by the general formula [2] is: It exceeds 50% by mass of the total polymerization units constituting the fluoropolymer, preferably 60% by mass or more, more preferably 70% by mass or more. The ratio of the content of the ω-H type fluorinated monomer represented by the general formula [1] and the content of the ω-F type fluorinated monomer represented by the general formula [2] is 50 or more and 50 or less. Preferably, 60 or more and 40 or less are more preferable, and 70 or more and 30 or less are more preferable.
In the fluorine-containing polymer, a ω-H type fluorine-containing monomer represented by the general formula [1], a ω-F type fluorine-containing monomer represented by the general formula [2], and a monomer copolymerizable therewith respectively. Two or more types of structural units may be included.

Next, L ¹ and L ² representing a divalent substituent will be described. L ¹ and L ² are not limited as long as they are each independently a divalent substituent, but a structure represented by the following general formula [5] is more preferable.

General formula [5]

In general formula [5], X ³ is a single bond, * -COO-**, * -COS-**, * -OCO-**, * -CON (R ⁵ )-**, or * -O. Represents a divalent linking group represented by-**. Here, * represents a position bonded to the double bond side, and ** represents a position bonded to R ⁴ .
R ⁴ is an optionally substituted polymethylene group (eg, methylene group, ethylene group, trimethylene group, etc.), an optionally substituted phenylene group (eg, o-phenylene group, m-phenylene group). , P-phenylene group and the like, and a group that can be formed by any combination thereof. Among them, a polymethylene group is more preferable, and among the polymethylene groups, a methylene group, an ethylene group, a trimethylene group, and a tetramethylene group are preferable, and a methylene group and an ethylene group are more preferable.
R ⁵ represents a hydrogen atom or an alkyl group which may have a substituent having 1 to 8 carbon atoms, or an aryl group which may have a substituent having 6 to 20 carbon atoms. A 1-6 alkyl group is more preferable, and a hydrogen atom or a C1-C4 alkyl group is still more preferable.

The fluoroalkyl group-containing monomer represented by the general formula [1] is more preferably represented by the following general formula [3].
General formula [3]

In General Formula [3], X ¹ represents a substituent represented by —O—, —S—, —N (R ³ ) —, and p represents an integer of 1 to 8. X ¹ is more preferably —O— or —N (R ³ ) —, and most preferably —O—. As for p, 1-6 are more preferable, and it is still more preferable that it is 1-3. R ¹ and m are the same as those described in the general formula [1]. R ³ represents a hydrogen atom or an alkyl group which may have a substituent having 1 to 8 carbon atoms, or an aryl group which may have a substituent having 6 to 20 carbon atoms.

The fluoroalkyl group-containing monomer represented by the general formula [2] is more preferably represented by the following general formula [4].
General formula [4]

In General Formula [4], X ² represents a substituent represented by —O—, —S—, —N (R ³ ) —, and p represents an integer of 1 to 8. X ² is more preferably —O— or —N (R ³ ) —, and most preferably —O—. As for q, 1-6 are more preferable, and it is still more preferable that it is 1-3. R ² and n are the same as those described in the general formula [2]. R ³ is the same as that described in the general formula [3].

  Examples of the substituent that the fluoroalkyl group-containing monomer or the fluorine-containing polymer may have include the following. Hydroxyl group, halogen atom (for example, Cl, Br, F, I), cyano group, nitro group, carboxyl group, sulfo group, linear or cyclic alkyl group having 1 to 8 carbon atoms (for example, methyl, ethyl, isopropyl, n- Butyl, n-hexyl, cyclopropyl, cyclohexyl, 2-hydroxyethyl, 4-carboxybutyl, 2-methoxyethyl, 2-diethylaminoethyl), an alkenyl group having 1 to 8 carbon atoms (for example, vinyl, allyl, 2-hexenyl) , Alkynyl groups having 2 to 8 carbon atoms (for example, ethynyl, 1-butynyl, 3-hexynyl), aralkyl groups having 7 to 12 carbon atoms (for example, benzyl, phenethyl), aryl groups having 6 to 10 carbon atoms (for example, phenyl, naphthyl) 4-carboxyphenyl, 4-acetamidophenyl, 3-methanesulfonamidophenyl, -Methoxyphenyl, 3-carboxyphenyl, 3,5-dicarboxyphenyl, 4-methanesulfonamidophenyl, 4-butanesulfonamidophenyl), acyl groups having 1 to 10 carbon atoms (for example, acetyl, benzoyl, propanoyl, butanoyl) , An alkoxycarbonyl group having 2 to 10 carbon atoms (for example, methoxycarbonyl, ethoxycarbonyl), an aryloxycarbonyl group having 7 to 12 carbon atoms (for example, phenoxycarbonyl, naphthoxycarbonyl), a carbamoyl group having 1 to 10 carbon atoms (for example, Unsubstituted carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl), an alkoxy group having 1 to 8 carbon atoms (for example, methoxy, ethoxy, butoxy, methoxyethoxy), an aryloxy group having 6 to 12 carbon atoms (for example, fluorine). Noxy, 4-carboxyphenoxy, 3-methylphenoxy, naphthoxy), acyloxy groups having 2 to 12 carbon atoms (for example, acetoxy, benzoyloxy), sulfonyloxy groups having 1 to 12 carbon atoms (for example, methylsulfonyloxy, phenylsulfonyloxy) An amino group having 0 to 10 carbon atoms (for example, unsubstituted amino, dimethylamino, diethylamino, 2-carboxyethylamino), an acylamino group having 1 to 10 carbon atoms (for example, acetamide or benzamide), a sulfonyl having 1 to 8 carbon atoms An amino group (for example, methylsulfonylamino, phenylsulfonylamino, butylsulfonylamino, n-octylsulfonylamino), a ureido group having 1 to 10 carbon atoms (for example, ureido, methylureido), and a urethane group having 2 to 10 carbon atoms (for example, methoxycarbon). Bonylamino, ethoxycarbonylamino), C1-C12 alkylthio group (for example, methylthio, ethylthio, octylthio), C6-C12 arylthio group (for example, phenylthio, naphthylthio), C1-C8 alkylsulfonyl group (for example, Methylsulfonyl, butylsulfonyl), arylsulfonyl groups having 7 to 12 carbon atoms (for example, phenylsulfonyl, 2-naphthylsulfonyl), sulfamoyl groups having 0 to 8 carbon atoms (for example, unsubstituted sulfamoyl, methylsulfamoyl, etc.), heterocyclic rings Groups (for example, 4-pyridyl, piperidino, 2-furyl, furfuryl, 2-thienyl, 2-pyrrolyl, 2-quinolylmorpholino) and the like. These substituents may be further substituted.

  Specific examples of the fluoroalkyl group-containing monomer represented by the general formula [1] are shown below, but are not limited thereto.

  Specific examples of the fluoroalkyl group-containing monomer represented by the general formula [2] are shown below, but are not limited thereto.

The monomer copolymerizable with the fluorine-containing monomer represented by the general formula [1] or [2] contained in the fluorine-containing polymer is not particularly limited as long as it can be copolymerized. For example, Polymer Handbook 2nd ed. , J .; Brandrup, Wiley Interscience (1975) Chapter 2, Pages 1-483 can be used.
For example, it has one addition polymerizable unsaturated bond selected from acrylic acid, methacrylic acid, acrylic esters, methacrylic esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, styrenes, etc. Examples thereof include compounds.

Specifically, the following monomers can be mentioned.
Acrylic esters:
Methyl acrylate, ethyl acrylate, propyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate, trimethylolpropane monoacrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, etc.

Methacrylic acid esters:
Methyl methacrylate, ethyl methacrylate, propyl methacrylate, chloroethyl methacrylate, 2-hydroxyethyl methacrylate, trimethylolpropane monomethacrylate, benzyl methacrylate, methoxybenzyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, etc.

Acrylamides:
Acrylamide, N-alkyl acrylamide (alkyl group having 1 to 3 carbon atoms, for example, methyl group, ethyl group, propyl group), N, N-dialkyl acrylamide (alkyl group having 1 to 6 carbon atoms), N-hydroxyethyl-N-methylacrylamide, N-2-acetamidoethyl-N-acetylacrylamide and the like.

Methacrylamide:
Methacrylamide, N-alkylmethacrylamide (alkyl group having 1 to 3 carbon atoms, such as methyl, ethyl, propyl group), N, N-dialkylmethacrylamide (alkyl group having 1 to 6 carbon atoms) ), N-hydroxyethyl-N-methylmethacrylamide, N-2-acetamidoethyl-N-acetylmethacrylamide and the like.

Allyl compounds:
Allyl esters (eg allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, etc.), allyloxyethanol, etc.

Vinyl ethers:
Alkyl vinyl ethers (eg hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethyl hexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether, hydroxyethyl vinyl ether, Diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, etc.

Vinyl esters:
Vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valerate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, vinyl butoxyacetate, vinyl lactate, vinyl-β-phenyl Butyrate, vinyl cyclohexyl carboxylate, etc.

Dialkyl itaconates:
Dimethyl itaconate, diethyl itaconate, dibutyl itaconate, etc.
Dialkyl or monoalkyl esters of fumaric acid:
Dibutyl fumarate, etc.

Other:
Crotonic acid, itaconic acid, acrylonitrile, methacrylonitrile, maleilonitrile, styrene, etc.
Among these, the monomer represented by the general formula [6] is preferable.

General formula [6]

In the general formula [6], R ⁶ represents a hydrogen atom, a methyl group or a halogen atom, more preferably a hydrogen atom or a methyl group. X ⁴ represents an oxygen atom, a sulfur atom or —N (R ⁸ ) —, more preferably an oxygen atom or —N (R ⁸ ) —, and still more preferably an oxygen atom. R ⁷ is an optionally substituted linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, an alkyl group containing a poly (oxyalkylene) group, or an optionally substituted aromatic group. Represents a group (for example, a phenyl group or a naphthyl group). A linear, branched or cyclic alkyl group having 1 to 12 carbon atoms or an aromatic group having 6 to 18 carbon atoms is more preferable, and a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms is more preferable. . R ⁸ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and further preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
Hereinafter, the poly (oxyalkylene) group will be described.

Poly (oxyalkylene) group can be represented by (OR) x, R is an alkylene group having 2 to 4 carbon atoms, such as _{-CH 2 CH 2 -, - CH} 2 CH 2 CH 2 -, - CH (CH ₃ ) CH ₂ — or —CH (CH ₃ ) CH (CH ₃ ) — is preferred. x represents an average degree of polymerization.
The oxyalkylene units in the poly (oxyalkylene) group may be the same as in poly (oxypropylene), or two or more different oxyalkylenes may be randomly distributed. It may be a linear or branched oxypropylene or oxyethylene unit, or a linear or branched oxypropylene unit block and an oxyethylene unit block.
The poly (oxyalkylene) chain may include those linked by one or more linking groups (for example, -CONH-Ph-NHCO-, -S-, etc .: Ph represents a phenylene group). When the linking group has a valence of 3 or more, a branched oxyalkylene unit is obtained.
When a copolymer containing a polymer unit having a poly (oxyalkylene) group is used in the present invention, the molecular weight of the poly (oxyalkylene) group is suitably from 250 to 3,000.
Poly (oxyalkylene) acrylates and methacrylates are commercially available hydroxypoly (oxyalkylene) materials such as “Pluronic” (Pluronic (Asahi Denka Kogyo Co., Ltd.), Adeka Polyether (Asahi Denka Kogyo Co., Ltd.) "Carbowax [Carbowax (Glico Products)]", "Triton" [Toriton (Rohm and Haas (Rohm and Haas)) and PEG (Daiichi Kogyo Seiyaku Co., Ltd.) Can be produced by reacting them with acrylic acid, methacrylic acid, acrylic chloride, methacryl chloride or acrylic anhydride, etc. Separately, poly (oxyalkylene) diacrylate produced by a known method is used. You can also.

Specific examples of the monomer represented by the general formula [6] include the specific examples of the acrylic esters, methacrylic esters, acrylamides, or methacrylamides shown above, and the following poly (oxyalkylene) groups. Although the specific example of what contains is mentioned, it is not limited to these. Poly (oxyalkylene) is often a mixture of compounds having different degrees of polymerization X, and even in the compounds shown as specific examples, the degree of polymerization is expressed by an integer close to the average of the degrees of polymerization.
Specific examples of the monomer represented by the general formula [6] are given below.

  The amount of the polymerized unit of the monomer represented by the general formula [6] preferably used in the present invention is preferably 50% by mass or less based on the total polymerized units constituting the fluoropolymer, and is 40% by mass. More preferably, it is more preferably 30% by mass or less.

  In addition, some of the fluorine-based chemical products produced by the electrolytic fluorination method that has been favorably used in the past are substances that have low biodegradability and high bioaccumulation, and to a lesser extent reproductive toxicity. There is concern about having developmental toxicity. It can also be said that it is industrially advantageous that the fluoropolymer having a hydrogen atom at the terminal of the fluoroalkyl group according to the present invention is a more environmentally safe substance.

  The higher the fluorine atom content (mass% of fluorine atoms with respect to the total mass of the polymer) of the fluoroalkyl group-containing fluoropolymer used in the present invention, the more effective the coating unevenness prevention is, and it is preferably 25% by mass or more. More preferably, it is at least 35% by mass, and even more preferably at least 35% by mass.

  The preferred mass average molecular weight of the fluoropolymer used in the present invention is preferably 3000 to 100,000, more preferably 4000 to 80,000, and even more preferably 5,000 to 60,000.

  Here, the mass average molecular weight and the molecular weight are converted to polystyrene by GTH analyzer using a column of TSKgel GMHxL, TSKgel G4000HxL, TSKgel G2000HxL (both trade names manufactured by Tosoh Corporation), and solvent THF and differential refractometer detection. The content is the area% of the peak in the molecular weight range when the peak area of the component having a molecular weight of 300 or more is defined as 100%.

  The fluorine-containing polymer used in the present invention can be produced by a known and conventional method. For example, it is produced by adding a general-purpose radical polymerization initiator and polymerizing monomers such as (meth) acrylate having a fluoroalkyl group and (meth) acrylate having a polyoxyalkylene group in an organic solvent. Come. Alternatively, other addition-polymerizable unsaturated compounds can be added in some cases and produced in the same manner as described above. Depending on the polymerizability of each monomer, a dropping polymerization method in which a monomer and an initiator are added dropwise to a reaction vessel is also effective for obtaining a polymer having a uniform composition.

  Examples of specific structures of the fluorine-containing polymer used in the present invention are shown below, but this is not restrictive. In addition, the number represented by a and b in a formula shows the mass ratio of each monomer component. Mw represents a mass average molecular weight.

  The optical film of the present invention contains at least one fluoroalkyl group-containing fluorine-containing polymer as described above, and may contain two or more kinds.

  The coating composition containing the fluorine-containing polymer for producing the optical film of the present invention can contain components other than the fluorine-containing polymer in addition to the above-mentioned components without particular limitation. That is, saturated hydrocarbons (n-hexane, n-octane, etc.), aromatic hydrocarbons (toluene, xylene, chlorobenzene, etc.), ketones (acetone, 2-butanone, 4-methyl-2-pentanone, isophorone, Cyclohexanone), alcohols (methyl alcohol, isopropyl alcohol, n-butyl alcohol, 2-methoxyethanol, 1-methoxy-2-propanol, cellosolve, butyl cellosolve, butyl carbitol, carbitol acetate, etc.), esters (methyl acetate) , Ethyl acetate, butyl acetate, etc.), amides (N, N-dimethylformamide, N, N-dimethylacetamide, N, N-dimethylimidazolinone, etc.), halogenated solvents (1,1,1-trichloroethane, chloroform, Perfluoroocta Etc.), organic solvents such as ethers (tetrahydrofuran, dioxane, etc.), water, and various resins such as acrylic resin, urethane resin, phenol resin, polyester resin, alkyd resin, epoxy resin, olefin resin, vinyl resin, fluorine resin, etc. , Organic / inorganic pigments, dyes, carbon and other colorants, rod-like liquid crystal compounds, discotic liquid crystal compounds, etc., monofunctional or polyfunctional polymerizable compounds, silica, titanium oxide, zinc oxide, aluminum oxide , Inorganic powders such as zirconium oxide, calcium oxide, calcium carbonate, organic fine powders such as higher fatty acids, poly (vinylidene fluoride), poly (tetrafluoroethylene), polyethylene, polymethyl methacrylate, photosensitizers, polymerization initiators, light resistance Property improver, weather resistance improver, antioxidant, heat stabilizer, It is possible to use various components selected according to the purpose, such as foaming agents, viscosity modifiers, gloss modifiers, fluorosurfactants, silicone surfactants, hydrocarbon surfactants, etc. Is possible.

The amount of the fluoroalkyl group-containing fluoropolymer added to the coating composition is preferably 0.001% by mass to 5.0% by mass, more preferably 0.01% by mass to 2% by mass.
The coating composition preferably has a water content of 30% by mass or less, more preferably 10% by mass or less, from the viewpoint of solubility of the additive.

  When producing the optical film of the present invention, a material for expressing the function is added to the coating composition, and coating is performed. As a material for expressing the function, inorganic fine particles (titanium dioxide, zirconium oxide, silica, etc.) dispersion and organic substances (fluorine-containing polymer, heat and / or photocurable polymer, etc.) for adjusting the refractive index, Examples thereof include liquid crystal compounds for exhibiting optical anisotropy (rod-like liquid crystal compounds, discotic liquid crystal compounds, polymer liquid crystal compounds, and the like).

The constituent materials of the optical film of the present invention will be described.
[Support]
The support of the present invention is preferably glass or a transparent polymer film.
The support preferably has a light transmittance of 80% or more. Examples of the polymer constituting the polymer film include cellulose esters (eg, cellulose acetate, cellulose diacetate), norbornene-based polymers, and polymethyl methacrylate. A commercially available polymer (for norbornene polymers, both Arton and Zeonex are trade names)) may be used.
Among these, cellulose esters are preferable, and lower fatty acid esters of cellulose are more preferable. Lower fatty acid means a fatty acid having 6 or less carbon atoms. Particularly, the number of carbon atoms is preferably 2 (cellulose acetate), 3 (cellulose propionate) or 4 (cellulose butyrate), and cellulose acetate is particularly preferred. Mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate may be used.

In addition, even a conventionally known polymer such as polycarbonate or polysulfone, which easily develops birefringence, can exhibit birefringence by modifying the molecule as described in International Publication No. 00/26705 pamphlet. Can be used for the optical film of the present invention.
When using the optical film of the present invention for a polarizing plate protective film or a retardation film, it is preferable to use cellulose acetate having an acetylation degree of 55.0 to 62.5% as the polymer film. The acetylation degree is more preferably 57.0 to 62.0%.

The degree of acetylation means the amount of bound acetic acid per unit mass of cellulose. The degree of acetylation is determined by measurement and calculation of the degree of acetylation in ASTM: D-817-91 (test method for cellulose acetate and the like).
The viscosity average degree of polymerization (DP) of cellulose acetate is preferably 250 or more, and more preferably 290 or more. Cellulose acetate preferably has a narrow molecular weight distribution of Mw / Mn (Mw is a mass average molecular weight, Mn is a number average molecular weight) by gel permeation chromatography. The specific value of Mw / Mn is preferably 1.0 to 1.7, more preferably 1.0 to 1.65, and most preferably 1.0 to 1.6. preferable.

In cellulose acetate, the hydroxyl groups at the 2-position, 3-position and 6-position of cellulose are not evenly substituted, but the substitution degree at the 6-position tends to be small. In the polymer film used in the present invention, it is preferable that the 6-position substitution degree of cellulose is the same as or higher than that of the 2-position and 3-position.
The ratio of the substitution degree at the 6-position to the total substitution degree at the 2-position, the 3-position, and the 6-position is preferably 30 to 40%, more preferably 31 to 40%, and more preferably 32 to 40%. Most preferably it is. The substitution degree at the 6-position is preferably 0.88 or more. The degree of substitution at each position can be measured by NMR. Cellulose acetate having a high degree of substitution at the 6-position is a synthesis example described in [Synthesis Example 1] and paragraphs [0048] to [0049] described in paragraphs [0043] to [0044] of JP-A No. 11-5851. 2 and by referring to the method of [Synthesis Example 3] described in paragraphs [0051] to [0052].

Hereinafter, the case where the optical film of the present invention is used as an optical compensation film will be described in more detail.
[Optically anisotropic layer]
The optically anisotropic layer is preferably designed so as to compensate for the liquid crystal compound in the liquid crystal cell in the black display of the liquid crystal display device. The alignment state of the liquid crystal compound in the liquid crystal cell in black display varies depending on the mode of the liquid crystal display device. The alignment state of the liquid crystal compound in this liquid crystal cell is described in IDW'00, FMC7-2, P411-414.
The optically anisotropic layer is formed directly from liquid crystalline molecules on the support, or is formed from liquid crystalline molecules via an alignment film. The alignment film preferably has a thickness of 10 μm or less.
Liquid crystalline molecules used for the optically anisotropic layer include rod-like liquid crystalline molecules and discotic compounds. The rod-like liquid crystal molecules and discotic compounds may be high-molecular liquid crystals or low-molecular liquid crystals, and further include those in which the low-molecular liquid crystals are cross-linked and no longer exhibit liquid crystallinity.
The optically anisotropic layer can be formed by applying a liquid crystal molecule and, if necessary, a coating liquid containing a polymerizable initiator and optional components on the alignment film.
A preferred example of the alignment film of the present invention is described in JP-A-8-338913.

As the solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane, tetrachloroethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination.
When producing an optical film with very high uniformity as in the present invention, the surface tension of the coating solution is preferably 30 mN / m or less, more preferably 28 mN / m or less, and 25 mN / m. More preferably, it is as follows.
The coating liquid can be applied by a known method (eg, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).
The thickness of the optically anisotropic layer is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and most preferably 1 to 10 μm.

(Rod-like liquid crystalline molecules)
Examples of rod-like liquid crystalline molecules include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used.
The rod-like liquid crystalline molecule includes a metal complex. In addition, a liquid crystal polymer containing a rod-like liquid crystalline molecule in a repeating unit can also be used as the rod-like liquid crystalline molecule. In other words, the rod-like liquid crystal molecule may be bonded to a (liquid crystal) polymer.
For rod-like liquid crystalline molecules, see Chapter 4, Chapter 7 and Chapter 11 of the Chemistry of the Quarterly Chemistry Vol. 22 (1994) The Chemical Society of Japan, and the 142th Committee of the Japan Society for the Promotion of Science. Described in Chapter 3.
The birefringence of the rod-like liquid crystal molecule is preferably in the range of 0.001 to 0.7.
The rod-like liquid crystalline molecule preferably has a polymerizable group in order to fix its alignment state. The polymerizable group is preferably an unsaturated polymerizable group or an epoxy group, more preferably an unsaturated polymerizable group, and most preferably an ethylenically unsaturated polymerizable group.

(Discotic compound)
Discotic compounds include C.I. Benzene derivatives described in a research report of Destrade et al. (Mol. Cryst. 71, 111 (1981)), C.I. Destrode et al. (Mol. Cryst. 122, 141 (1985), Physics lett, A, 78, 82 (1990)) described in The cyclohexane derivatives described in the research report of Kohne et al. (Angew. Chem. 96, 70 (1984)) and M.M. Lehn et al. (J. Chem. Commun., 1794 (1985)), J. Chem. Azacrown-type and phenylacetylene-type macrocycles described in the research report of Zhang et al. (J. Am. Chem. Soc. 116, 2655 (1994)) are included.

  The discotic compound includes a compound having a liquid crystallinity in which a linear alkyl group, an alkoxy group, and a substituted benzoyloxy group are radially substituted as a side chain of the mother nucleus with respect to the mother nucleus at the center of the molecule. It is. The molecule or the assembly of molecules is preferably a compound having rotational symmetry and imparting a certain orientation. In the optically anisotropic layer formed from the discotic liquid crystalline molecules, the compound finally contained in the optically anisotropic layer does not need to be a discotic liquid crystalline molecule. Also included are compounds having a group that reacts with heat or light and, as a result, polymerized or cross-linked by reaction with heat or light, resulting in a high molecular weight and loss of liquid crystallinity. Preferred examples of the discotic compound are described in JP-A-8-50206. Moreover, about superposition | polymerization of a discotic compound, Unexamined-Japanese-Patent No. 8-27284 has description.

  In order to fix the discotic compound by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic compound. However, when the polymerizable group is directly connected to the disc-shaped core, it becomes difficult to maintain the orientation state in the polymerization reaction. Therefore, a linking group is introduced between the discotic core and the polymerizable group. Therefore, the discotic compound having a polymerizable group is preferably a compound represented by the following formula (III).

(III) D (-LQ) n
In formula (III), D is a discotic core; L is a divalent linking group, Q is a polymerizable group, and n is an integer of 4-12.
An example of the disk-shaped core (D) is shown below. In each of the following examples, LQ (or QL) means a combination of a divalent linking group (L) and a polymerizable group (Q).

  In the formula (III), the divalent linking group (L) is selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, —CO—, —NH—, —O—, —S—, and combinations thereof. A divalent linking group is preferred. The divalent linking group (L) is a divalent combination of at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, -CO-, -NH-, -O-, and -S-. More preferably, it is a linking group. The divalent linking group (L) is most preferably a divalent linking group in which at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, -CO- and -O- are combined. . The alkylene group preferably has 1 to 12 carbon atoms. The alkenylene group preferably has 2 to 12 carbon atoms. The number of carbon atoms in the arylene group is preferably 6-10.

Examples of the divalent linking group (L) are shown below. The left side is bonded to the discotic core (D), and the right side is bonded to the polymerizable group (Q). AL represents an alkylene group or an alkenylene group, and AR represents an arylene group. The alkylene group, alkenylene group and arylene group may have a substituent (eg, an alkyl group).
L1: -AL-CO-O-AL-
L2: -AL-CO-O-AL-O-
L3: -AL-CO-O-AL-O-AL-
L4: -AL-CO-O-AL-O-CO-
L5: -CO-AR-O-AL-
L6: -CO-AR-O-AL-O-
L7: -CO-AR-O-AL-O-CO-
L8: -CO-NH-AL-
L9: -NH-AL-O-
L10: -NH-AL-O-CO-

L11: -O-AL-
L12: -O-AL-O-
L13: -O-AL-O-CO-
L14: -O-AL-O-CO-NH-AL-
L15: -O-AL-S-AL-
L16: -O-CO-AR-O-AL-CO-
L17: -O-CO-AR-O-AL-O-CO-
L18: -O-CO-AR-O-AL-O-AL-O-CO-
L19: -O-CO-AR-O-AL-O-AL-O-AL-O-CO-
L20: -S-AL-
L21: -S-AL-O-
L22: -S-AL-O-CO-
L23: -S-AL-S-AL-
L24: -S-AR-AL-

In the formula (III), the polymerizable group (Q) is determined according to the kind of the polymerization reaction. The polymerizable group (Q) is preferably an unsaturated polymerizable group or an epoxy group, more preferably an unsaturated polymerizable group, and most preferably an ethylenically unsaturated polymerizable group.
In formula (III), n is an integer of 4-12. A specific number is determined according to the type of the disk-shaped core (D). In addition, although the combination of several L and Q may differ, it is preferable that it is the same.

The alignment of liquid crystal molecules includes hybrid alignment, homogeneous alignment, homeotropic alignment, and the like. The optical film of the present invention can also be applied to complicated alignment including hybrid alignment.
In the hybrid orientation, the angle between the major axis (disk surface) of the discotic compound and the surface of the support, that is, the inclination angle, increases with increasing distance from the surface of the polarizing film in the depth direction of the optically anisotropic layer or is decreasing. The angle preferably decreases with increasing distance. Further, the change in the inclination angle can be continuous increase, continuous decrease, intermittent increase, intermittent decrease, change including continuous increase and continuous decrease, or intermittent change including increase and decrease. . The intermittent change includes a region where the inclination angle does not change in the middle of the thickness direction. Even if a region where the angle does not change is included, it may be increased or decreased as a whole. However, it is preferred that the tilt angle changes continuously.

  The average direction of the major axis (disk surface) of the discotic compound (average of the major axis direction of each molecule) is generally determined by selecting the discotic compound or the material of the alignment film, or by selecting the rubbing treatment method. Can be adjusted. Moreover, the major axis (disk surface) direction of the discotic compound on the surface side (air side) can be generally adjusted by selecting the type of additive used together with the discotic compound or the discotic compound. Examples of the additive used together with the discotic compound include a plasticizer, a surfactant, a polymerizable monomer and a polymer. The degree of change in the orientation direction of the major axis can also be adjusted by selecting liquid crystalline molecules and additives as described above.

  The plasticizer, surfactant, and polymerizable monomer used together with the discotic compound are preferably compatible with the discotic compound and can change the tilt angle of the discotic compound or do not inhibit the orientation. Among the additive components, addition of a polymerizable monomer (eg, a compound having a vinyl group, a vinyloxy group, an acryloyl group and a methacryloyl group) is preferable. The amount of the compound added is generally in the range of 1 to 50% by mass and preferably in the range of 5 to 30% by mass with respect to the discotic compound. In addition, when a monomer having 4 or more polymerizable reactive functional groups is mixed and used, the adhesion between the alignment film and the optically anisotropic layer can be improved.

The optically anisotropic layer contains the above-described fluoroaliphatic polymer according to the present invention. However, another polymer may be used together with the discotic compound, and the polymer includes a discotic compound and a certain amount. It is preferable that they have compatibility and can change the tilt angle of the discotic compound.
A cellulose ester can be mentioned as an example of a polymer. Preferred examples of the cellulose ester include cellulose acetate, cellulose acetate propionate, hydroxypropyl cellulose, and cellulose acetate butyrate. The addition amount of the polymer is preferably in the range of 0.1 to 10% by mass and in the range of 0.1 to 8% by mass with respect to the discotic compound so as not to inhibit the orientation of the discotic compound. It is more preferable that it is in the range of 0.1 to 5% by mass.
The discotic nematic liquid crystal phase-solid phase transition temperature of the discotic compound is preferably 70 to 300 ° C, and more preferably 70 to 170 ° C.

(Fixing the alignment state of liquid crystalline molecules)
The aligned liquid crystal molecules can be fixed while maintaining the alignment state. The immobilization is preferably performed by a polymerization reaction. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. A photopolymerization reaction is preferred.
Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatics. Group acyloin compounds (described in US Pat. No. 2,722,512), polynuclear quinone compounds (described in US Pat. Nos. 3,046,127 and 2,951,758), combinations of triarylimidazole dimers and p-aminophenyl ketone (US patents) No. 3549367), acridine and phenazine compounds (JP-A-60-105667, US Pat. No. 4,239,850) and oxadiazole compounds (US Pat. No. 4,221,970).

The amount of the photopolymerization initiator used is preferably in the range of 0.01 to 20% by mass, more preferably in the range of 0.5 to 5% by mass, based on the solid content of the coating solution.
It is preferable to use ultraviolet rays for light irradiation for polymerization of liquid crystalline molecules.
The irradiation energy is preferably in the range of ^{20mJ / cm 2 ~50J / cm 2} , more preferably in the range of 20~5000mJ / cm ^2, more preferably in the range of 100 to 800 mJ / cm ² . In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions.
A protective layer may be provided on the optically anisotropic layer.

[Polarizing film]
The optical film of the present invention exhibits its functions remarkably by being bonded to a polarizing plate or used as a protective film for a polarizing plate.
The polarizing film of the present invention is preferably a coating type polarizing film typified by Optiva, or a polarizing film comprising a binder and iodine or a dichroic dye.
Iodine and dichroic dye in the polarizing film exhibit deflection performance by being oriented in the binder. It is preferable that the iodine and the dichroic dye are aligned along the binder molecule, or the dichroic dye is aligned in one direction by self-assembly such as liquid crystal.
Currently, a general-purpose polarizing film is produced by immersing a stretched polymer in a solution of iodine or dichroic dye in a bath and allowing the iodine or dichroic dye to penetrate into the binder. Is common.
In general-purpose polarizing films, iodine or dichroic dye is distributed about 4 μm (about 8 μm on both sides) from the polymer surface, and a thickness of at least 10 μm is necessary to obtain sufficient polarization performance. The penetrability can be controlled by the solution concentration of iodine or dichroic dye, the temperature of the bath, and the immersion time.
As described above, the lower limit of the binder thickness is preferably 10 μm. On the other hand, the upper limit of the thickness is not particularly limited, but the thinner the better, from the viewpoint of the light leakage phenomenon that occurs when the polarizing plate is used in a liquid crystal display device.
Currently, it is preferably a general-purpose polarizing plate (about 30 μm) or less, preferably 25 μm or less, and more preferably 20 μm or less. When the thickness is 20 μm or less, the light leakage phenomenon is not observed on a 17-inch liquid crystal display device.

The binder of the polarizing film may be cross-linked. As the crosslinked binder, a polymer that can be crosslinked per se can be used. A polarizing film can be formed by reacting a polymer having a functional group or a binder obtained by introducing a functional group into a polymer between the binders by light, heat, or pH change.
Moreover, you may introduce | transduce a crosslinked structure into a polymer with a crosslinking agent. It can be formed by cross-linking between binders by introducing a bonding group derived from the cross-linking agent between binders using a cross-linking agent which is a compound having high reaction activity.
Crosslinking is generally carried out by applying a coating liquid containing a polymer or a mixture of a polymer and a crosslinking agent on a transparent support and then heating. Since it is only necessary to ensure durability at the stage of the final product, the crosslinking treatment may be performed at any stage until the final polarizing plate is obtained.

  As the binder for the polarizing film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used. Examples of polymers include polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, polystyrene, gelatin, polyvinyl alcohol, modified polyvinyl alcohol, poly (N-methylolacrylamide), polyvinyltoluene, chlorosulfonated polyethylene, nitrocellulose, chlorinated Polyolefin (eg, polyvinyl chloride), polyester, polyimide, polyvinyl acetate, polyethylene, carboxymethyl cellulose, polypropylene, polycarbonate and copolymers thereof (eg, acrylic acid / methacrylic acid copolymer, styrene / maleimide copolymer, styrene) / Vinyl toluene copolymer, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer). Water-soluble polymers (eg, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol and modified polyvinyl alcohol) are preferred, gelatin, polyvinyl alcohol and modified polyvinyl alcohol are more preferred, and polyvinyl alcohol and modified polyvinyl alcohol are most preferred. .

The saponification degree of polyvinyl alcohol and modified polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%, and most preferably 85 to 100%. As for the polymerization degree of polyvinyl alcohol, 100-5000 are preferable.
Modified polyvinyl alcohol is obtained by introducing a modifying group into polyvinyl alcohol by copolymerization modification, chain transfer modification or block polymerization modification. In the copolymerization modification, COONa, Si (OH) ₃ , N (CH ₃ ) ₃ .Cl, C ₉ H ₁₉ COO, SO ₃ Na, C ₁₂ H ₂₅ can be introduced as modifying groups. In chain transfer modification, COONa, SH, or SC ₁₂ H ₂₅ can be introduced as a modifying group. The degree of polymerization of the modified polyvinyl alcohol is preferably 100 to 3000. The modified polyvinyl alcohol is described in JP-A-8-338913, JP-A-9-152509 and JP-A-9-316127.
Unmodified polyvinyl alcohol and alkylthio-modified polyvinyl alcohol having a saponification degree of 85 to 95% are particularly preferable. Two or more kinds of polyvinyl alcohol and modified polyvinyl alcohol may be used in combination.

When a large amount of the crosslinking agent for the binder is added, the heat and humidity resistance of the polarizing film can be improved. However, when 50 mass% or more of a crosslinking agent is added to the binder, the orientation of iodine or the dichroic dye is lowered. 0.1-20 mass% is preferable with respect to a binder, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is more preferable.
The binder contains some crosslinking agent that has not reacted even after the crosslinking reaction has been completed. However, the amount of the remaining crosslinking agent is preferably 1.0% by mass or less in the binder, and more preferably 0.5% by mass or less. When the crosslinking agent is contained in the binder layer in an amount exceeding 1.0% by mass, there may be a problem in durability. That is, when a polarizing film having a large amount of residual crosslinking agent is incorporated in a liquid crystal display device and used for a long time or left in a high-temperature and high-humidity atmosphere for a long time, the degree of polarization may decrease.
The crosslinking agent is described in US Reissue Patent 23297. Boron compounds (eg, boric acid, borax) can also be used as a crosslinking agent.

As the dichroic dye, an azo dye, stilbene dye, pyrazolone dye, triphenylmethane dye, quinoline dye, oxazine dye, thiazine dye or anthraquinone dye is used. The dichroic dye is preferably water-soluble. The dichroic dye preferably has a hydrophilic substituent (eg, sulfo, amino, hydroxyl).
Examples of dichroic dyes include C.I. I. Direct Yellow 12, C.I. I. Direct Orange 39, C.I. I. Direct Orange 72, C.I. I. Direct Red 39, C.I. I. Direct Red 79, C.I. I. Direct Red 81, C.I. I. Direct Red 83, C.I. I. Direct Red 89, C.I. I. Direct Violet 48, C.I. I. Direct Blue 67, C.I. I. Direct Blue 90, C.I. I. Direct Green 59, C.I. I. Acid Red 37 is included. As for the dichroic dyes, those described in JP-A-1-161202, 1-172906, 1-172907, 1-183602, 1-248105, 1-265205, 7-261024 are used. There are descriptions in each publication.
The dichroic dye is used as a free acid or an alkali metal salt, ammonium salt or amine salt. By blending two or more kinds of dichroic dyes, polarizing films having various hues can be produced. A polarizing film using a compound (pigment) that exhibits a black color when the polarization axes are orthogonal to each other, or a polarizing film or a polarizing plate in which various dichroic molecules are blended so as to exhibit a black color, have both a single-plate transmittance and a polarizability. It is excellent and preferable.

  In order to increase the contrast ratio of the liquid crystal display device, the transmittance of the polarizing plate is preferably higher and the degree of polarization is preferably higher. The transmittance of the polarizing plate is preferably in the range of 30 to 50%, more preferably in the range of 35 to 50%, and in the range of 40 to 50% in the light having a wavelength of 550 nm (of the polarizing plate). Most preferably, the maximum value of the single plate transmittance is 50%. The degree of polarization is preferably in the range of 90 to 100%, more preferably in the range of 95 to 100%, and most preferably in the range of 99 to 100% in light having a wavelength of 550 nm.

  It is also possible to arrange the polarizing film and the optically anisotropic layer, or the polarizing film and the alignment film via an adhesive. As the adhesive, a polyvinyl alcohol resin (including a modified polyvinyl alcohol with an acetoacetyl group, a sulfonic acid group, a carboxyl group, or an oxyalkylene group) or an aqueous boron compound solution can be used. Of these, polyvinyl alcohol resins are preferred. The thickness of the adhesive layer is preferably in the range of 0.01 to 10 μm after drying, and particularly preferably in the range of 0.05 to 5 μm.

(Manufacture of polarizing plates)
From the viewpoint of yield, the polarizing film is stretched at an angle of 10 to 80 degrees with respect to the longitudinal direction (MD direction) of the polarizing film (stretching method) or rubbed (rubbing method). It is preferable to dye with a dichroic dye. The tilt angle is preferably stretched so as to match the angle formed between the transmission axis of the two polarizing plates bonded to both sides of the liquid crystal cell constituting the LCD and the vertical or horizontal direction of the liquid crystal cell.
A normal inclination angle is 45 °. Recently, however, devices that are not necessarily 45 ° have been developed for transmissive, reflective, and transflective LCDs, and it is preferable that the stretching direction can be arbitrarily adjusted in accordance with the design of the LCD.

In the stretching method, the stretching ratio is preferably 2.5 to 30.0 times, and more preferably 3.0 to 10.0 times. Stretching can be performed by dry stretching in air. Moreover, you may implement wet extending | stretching in the state immersed in water. The stretch ratio of dry stretching is preferably 2.5 to 5.0 times, and the stretch ratio of wet stretching is preferably 3.0 to 10.0 times. The stretching step may be performed in several steps including oblique stretching. By dividing into several times, it is possible to stretch more uniformly even at high magnification. Before the oblique stretching, a slight stretching (a degree to prevent shrinkage in the width direction) may be performed horizontally or vertically.
Stretching can be performed by performing tenter stretching in biaxial stretching in different steps. The biaxial stretching is the same as the stretching method performed in normal film formation. In biaxial stretching, stretching is performed at different speeds on the left and right, so that the thickness of the binder film before stretching needs to be different on the left and right. In casting film formation, the flow rate of the binder solution can be differentiated between the left and right sides by tapering the die.
As described above, a binder film that is obliquely stretched by 10 to 80 degrees with respect to the MD direction of the polarizing film is produced.

In the rubbing method, a rubbing treatment method widely adopted as a liquid crystal alignment treatment process of LCD can be applied. That is, orientation is obtained by rubbing the surface of the film in a certain direction using paper, gauze, felt, rubber, nylon, or polyester fiber. Generally, it is carried out by rubbing several times using a cloth in which fibers having a uniform length and thickness are planted on average. It is preferable to carry out using a rubbing roll in which the roundness, cylindricity, and deflection (eccentricity) of the roll itself are all 30 μm or less. The wrap angle of the film on the rubbing roll is preferably 0.1 to 90 °. However, as described in JP-A-8-160430, a stable rubbing treatment can be obtained by winding 360 ° or more.
When rubbing a long film, it is preferable to transport the film at a speed of 1 to 100 m / min with a constant tension by a transport device. The rubbing roll is preferably rotatable in the horizontal direction with respect to the film traveling direction for setting an arbitrary rubbing angle. It is preferable to select an appropriate rubbing angle in the range of 0 to 60 °. When used in a liquid crystal display device, 40 to 50 ° is preferable, and 45 ° is particularly preferable.
A polymer film is preferably disposed on the surface of the polarizing film opposite to the optically anisotropic layer (arrangement of optically anisotropic layer / polarizing film / polymer film).

[Liquid Crystal Display]
A preferred form of the optically anisotropic layer in each liquid crystal mode will be described below.
(TN mode liquid crystal display)
The TN mode liquid crystal cell is most frequently used as a color TFT liquid crystal display device, and is described in many documents.
The alignment state in the liquid crystal cell in the TN mode black display is an alignment state in which the rod-like liquid crystal molecules rise at the center of the cell and the rod-like liquid crystal molecules lie near the cell substrate.

The rod-like liquid crystalline molecules in the center of the cell are compensated with a disk-like liquid crystalline molecule or support of homeotropic orientation (horizontal orientation in which the disc surface lies), and the rod-like liquid crystalline molecules in the vicinity of the cell substrate Thus, it can be compensated by discotic liquid crystalline molecules having a hybrid orientation (an orientation in which the inclination of the major axis changes with the distance from the polarizing film).
In addition, for the rod-like liquid crystalline molecules in the center of the cell, the rod-like liquid crystalline molecules in the homogeneous orientation (horizontal orientation in which the major axis lies) or the support are compensated for the rod-like liquid crystalline molecules in the vicinity of the cell substrate. In other words, it can be compensated by discotic liquid crystal molecules of hybrid orientation.

Homeotropic alignment liquid crystal molecules are aligned in a state where the angle between the long axis average alignment direction of the liquid crystal molecules and the plane of the polarizing film is 85 to 95 °.
The liquid crystal molecules of homogeneous alignment are aligned with the angle between the average alignment direction of the long axes of the liquid crystal molecules and the plane of the polarizing film being less than 5 °.
In the hybrid alignment liquid crystal molecules, the angle between the average alignment direction of the long axes of the liquid crystal molecules and the plane of the polarizing film is preferably larger than 15 °, and more preferably 15 ° to 85 °.

An optically anisotropic layer in which the support or discotic compound is homeotropically oriented, an optically anisotropic layer in which rod-like liquid crystalline molecules are homogeneously oriented, and further homogenously oriented with a homeotropically oriented discotic compound The optically anisotropic layer made of a mixture of rod-like liquid crystal molecules preferably has an Rth retardation value of 40 nm to 200 nm and an Re retardation value of 0 to 70 nm. The Rth retardation value (Rth) is a value defined by the following formula (I), and the Re retardation value (Re) is a value defined by the following formula (II).
(I) Rth = {(nx + ny) / 2−nz} × d
(II) Re = (nx−ny) × d
[In formulas (I) and (II), nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, and nz is the film refractive index. The refractive index in the thickness direction. And d is the thickness of the film].
Regarding the discotic liquid crystalline molecular layer that is homeotropically aligned (horizontal alignment) and the rod-like liquid crystalline molecular layer that is homogeneously aligned (horizontal alignment), see JP-A-12-304931 and JP-A-12-304932. Has been described. Japanese Patent Application Laid-Open No. 8-50206 discloses a disk-like liquid crystal molecular layer having a hybrid orientation.

(OCB mode liquid crystal display device)
The OCB mode liquid crystal cell is a bend alignment mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned in a substantially opposite direction (symmetrically) between the upper part and the lower part of the liquid crystal cell. Liquid crystal display devices using a bend alignment mode liquid crystal cell are disclosed in US Pat. Nos. 4,583,825 and 5,410,422. Since the rod-like liquid crystal molecules are symmetrically aligned at the upper and lower portions of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. Therefore, this liquid crystal mode is called an OCB (Optically Compensatory Bend) liquid crystal mode.
Similarly to the TN mode, the liquid crystal cell in the OCB mode is in a black display, and the alignment state in the liquid crystal cell is an alignment state in which the rod-like liquid crystal molecules rise at the center of the cell and the rod-like liquid crystal molecules lie in the vicinity of the cell substrate. .

  Since the TN mode and the alignment of the liquid crystal are the same in black display, the preferred mode is the same for the TN mode. However, since the OCB mode has a larger range in which the liquid crystal compound rises in the center of the cell than the TN mode, the optically anisotropic layer in which the discotic compound is homeotropically aligned, or the rod-like liquid crystal molecule It is necessary to slightly adjust the retardation value of the optically anisotropic layer that is homogeneously oriented. Specifically, the optically anisotropic layer in which the discotic compound on the support is homeotropically oriented, or the optically anisotropic layer in which the rod-like liquid crystalline molecules are homogeneously oriented has an Rth retardation value of 150 nm. ˜500 nm, and Re retardation value is preferably 20 to 70 nm.

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

In the black display of the VA mode liquid crystal display device, since most of the rod-like liquid crystalline molecules in the liquid crystal cell are in an upright state, the optically anisotropic layer in which the discotic compound is homeotropically aligned, or The liquid crystal compound is compensated by the optically anisotropic layer in which the rod-like liquid crystalline molecules are homogeneously oriented, and separately, the rod-like liquid crystalline molecules are homogeneously oriented, the average orientation direction of the major axis of the rod-like liquid crystalline molecules and the transmission axis of the polarizing film It is preferable to compensate the viewing angle dependency of the polarizing plate with an optically anisotropic layer having an angle with the direction of less than 5 °.
The optically anisotropic layer in which the support or the discotic compound is homeotropically oriented, or the optically anisotropic layer in which the rod-like liquid crystalline molecules are homogeneously oriented has an Rth retardation value of 150 nm to 500 nm, The retardation value is preferably 20 to 70 nm.

(Other liquid crystal display devices)
The ECB mode and STN mode liquid crystal display devices can be optically compensated in the same way as described above.

  The optical film of the present invention may be provided with a layer having antireflection ability (hereinafter sometimes referred to as an antireflection layer). In the case of providing the layer, various types of anti-reflection layers such as a single layer and a multilayer are known, but a multilayer structure generally has a structure in which a high refractive index layer and a low refractive index layer are alternately laminated. Is. As an example of the configuration, a layer composed of two layers of a high refractive index layer / a low refractive index layer from the transparent substrate side, or three layers having different refractive indexes, a medium refractive index layer (transparent support or described later) In which the refractive index is higher than that of the hard coat layer and lower than that of the high-refractive-index layer) / high-refractive-index layer / low-refractive-index layer. A laminate of these has also been proposed. Among them, in view of durability, optical characteristics, cost, productivity, and the like, it is preferable to apply a high refractive index layer / medium refractive index layer / low refractive index layer in this order on a support having a hard coat layer. A high refractive index layer (which may be provided with a middle refractive layer) on the substrate surface, and a low refractive index layer are laminated in order toward the air, and the optical film thickness of the high refractive index layer and the low refractive index layer with respect to the light wavelength An optical interference layer formed by setting to a certain value to form an antireflection laminate is particularly preferable as the antireflection layer, and the refractive index and film thickness can be calculated and calculated by measuring the spectral reflectance.

Moreover, when the strength of the film is required in the optical film of the present invention, a transparent hard coat layer can be provided.
The transparent hard coat layer can be generally formed by applying a coating solution containing an actinic ray curable or thermosetting component and then curing the coating solution. The actinic radiation curable component can be cured through a crosslinking reaction or the like by irradiation with actinic rays such as ultraviolet rays or electron beams. Typical examples of the actinic rays include ultraviolet rays and electron beams, but other components that are cured by actinic ray irradiation may be used. In general, UV curable components include compounds called polyfunctional acrylate monomers having 2 to 6 acrylate groups in the molecule, several in the molecule called urethane acrylate, polyester acrylate, and epoxy acrylate. Oligomer having a molecular weight of several hundred to several thousand having an acrylic ester group is used. However, many of these oligomer compounds have a small amount of acrylic groups introduced, and sufficient hardness cannot be obtained by themselves. Therefore, polyfunctional acrylate monomers are widely used as hard coat curable components that require higher hardness. It is used.

  Also, a coating composition containing a polyfunctional acrylate monomer as the resin-forming component of the hard coat layer and containing a powdery inorganic filler such as alumina, silica, titanium oxide and a polymerization initiator is disclosed in Japanese Patent Publication No. 02-60696. It is disclosed. Japanese Patent Publication No. 62-21815 discloses a photopolymerizable composition containing an inorganic charge material composed of silica or alumina surface-treated with alkoxysilane or the like. Japanese Patent Laid-Open No. 2000-52472 proposes a method of satisfying curl and scratch resistance by forming a hard coat layer into two layers and adding fine-particle silica to the first layer. Since the hardness of the hard coat layer is improved by these and the amount of cure shrinkage is also reduced, an embodiment in which inorganic fine particles are added is also preferable.

  The type of the optical film of the present invention is not particularly limited, and examples of the optical functional layer include a film having one or more of a colored layer, an antiglare layer, an antireflection layer, an optical compensation layer, and the like. The fluorine-containing polymer according to the present invention is preferably added to at least one of the layers formed on these optical films. The optical film of the present invention is particularly useful as an optical film having an optical compensation layer, an antiglare layer, an antireflection layer, and the like, which require strict film thickness and planar uniformity.

The present invention will be described in more detail based on examples, but the present invention is not limited thereto.
[Example 1]
(Synthesis of fluorinated polymer (P-15))

To a reactor equipped with a stirrer and a reflux condenser, 1H, 1H, 7H-dodecafluoroheptyl acrylate (manufactured by Daikin Industries, Ltd.) 36.0 g, 2- (perfluorohexyl) ethyl acrylate (manufactured by Daikin Industries, Ltd.) ) 4.0 g, 1.1 g of dimethyl-2,2′-azobisisobutyrate, and 30 g of 2-butanone were added and heated to 78 ° C. for 6 hours under a nitrogen atmosphere to complete the reaction. The weight average molecular weight was 1.6 × 10 ⁴ .

[Example 2]
(Synthesis of fluoropolymer (P-79))
In a reactor equipped with a stirrer and a reflux condenser, 32.0 g of 1H, 1H, 7H-dodecafluoroheptyl acrylate (manufactured by Daikin Industries, Ltd.), 2- (perfluorobutyl) ethyl acrylate (manufactured by Daikin Industries, Ltd.) ) 4.0 g, BLEMMER AP-400 (manufactured by NOF Corporation) 4.0 g, 1.1 g of dimethyl-2,2′-azobisisobutyrate, 30 g of 2-butanone were added and added under nitrogen atmosphere for 6 hours 78 The reaction was completed by heating to ° C. The weight average molecular weight was 1.5 × 10 ⁴ .

  A fluorine-containing polymer (P-11) was synthesized by a similar method.

[Example 3]
(Production of support)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution.

<Cellulose acetate solution composition>
Cellulose acetate (linter) with an acetylation degree of 60.9% 80 parts by mass Cellulose acetate (linter) with an acetylation degree of 60.8% 20 parts by mass Triphenyl phosphate (plasticizer) 7.8 parts by mass Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by mass Methylene chloride (first solvent) 300 parts by mass Methanol (second solvent) 54 parts by mass 1-butanol (third solvent) 11 parts by mass

<Preparation of retardation increasing agent solution>
In another mixing tank, 4 parts by mass of cellulose acetate (linter) with an acetylation degree of 60.9%, 16 parts by mass of the following retardation increasing agent, 0.5 parts by mass of silica fine particles (particle size 20 nm, Mohs hardness about 7) Then, 87 parts by mass of methylene chloride and 13 parts by mass of methanol were added and stirred while heating to prepare a retardation increasing agent solution.

<Preparation of dope>
A dope was prepared by mixing 36 parts by mass of the retardation increasing agent solution with 464 parts by mass of the cellulose acetate solution and stirring sufficiently. The addition amount of the retardation increasing agent was 5.0 parts by mass with respect to 100 parts by mass of cellulose acetate.

The obtained dope was cast using a band casting machine. After the film surface temperature on the band reached 40 ° C., the film was dried for 1 minute, and after the film having a residual solvent amount of 43% by mass was peeled off, it was dried in the width direction by using a tenter with 140 ° C. % Stretched. Then, it dried for 20 minutes with 135 degreeC dry air, and manufactured the support body (PK-1) whose residual solvent amount is 0.3 mass%.
The width of the obtained support (PK-1) was 1340 mm, and the thickness was 92 μm. When the retardation value (Re) at a wavelength of 590 nm was measured using an ellipsometer (M-150, manufactured by JASCO Corporation), it was 43 nm. Moreover, it was 175 nm when the retardation value (Rth) in wavelength 590nm was measured.
The produced support (PK-1) was immersed in a 2.0N potassium hydroxide solution (25 ° C.) for 2 minutes, neutralized with sulfuric acid, washed with pure water, and dried. The surface energy of this PK-1 was determined by the contact angle method and found to be 63 mN / m.
On this PK-1, an alignment film coating solution having the following composition was coated at a coating amount of 28 ml / m ² with a # 16 wire bar coater. Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 90 ° C. for 150 seconds.

(Production of optical compensation sheet with optically anisotropic layer)
<Alignment film coating solution composition>
The following modified polyvinyl alcohol 10 parts by weight Water 371 parts by weight Methanol 119 parts by weight Glutaraldehyde (crosslinking agent) 0.5 parts by weight

  The alignment film was rubbed in the direction of 45 ° with the slow axis (measured at a wavelength of 632.8 nm) of the support (PK-1).

<Formation of optically anisotropic layer>
Discotic liquid crystalline compounds (Exemplary compounds described in JP-A-7-306317)
(TP-53)) 41.01 Kg
Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 4.06Kg
Cellulose acetate butyrate (CAB531-1, manufactured by Eastman Chemical Co.) 0.35 kg
Photopolymerization initiator (IRGACURE 907, manufactured by Ciba Geigy Co., Ltd. 1.35 Kg
Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.45Kg

The above compound is dissolved in 102 kg of methyl ethyl ketone, 0.164 kg of fluoropolymer (P-15) is added to this solution to make a coating solution, and this is continuously coated on the alignment film with a # 3.6 wire bar. did. Next, after heating for 2 minutes at 130 ° C. to align the discotic liquid crystalline compound, UV irradiation is performed for 1 minute using a 120 W / cm high pressure mercury lamp at 100 ° C. to polymerize the discotic liquid crystalline compound. It was. Then, it stood to cool to room temperature. In this manner, an optical compensation sheet (KH-1) with an optically anisotropic layer was produced.
The Re retardation value of the optically anisotropic layer measured at a wavelength of 546 nm was 38 nm.
The polarizing plate produced as described below was arranged in a crossed Nicol arrangement, and when the unevenness of the obtained optical compensation sheet was observed, the unevenness could not be detected even when viewed from the front and the direction inclined to 60 ° from the normal line.

(Preparation of polarizing film)
PVA having an average polymerization degree of 4000 and a saponification degree of 99.8 mol% was dissolved in water to obtain a 4.0% aqueous solution. This solution was band-cast using a die having a taper and dried to form a film so that the width before stretching was 110 mm, the thickness was 120 μm at the left end, and 135 μm at the right end.
The film was peeled off from the band, and obliquely stretched in the 45 ° direction in a dry state, and immersed in an aqueous solution of 0.5 g / L iodine and 50 g / L potassium iodide for 1 minute at 30 ° C., and then 100 g boric acid. / L, potassium iodide 60 g / L in an aqueous solution at 70 ° C. for 5 minutes, further washed with water at 20 ° C. for 10 seconds and then dried at 80 ° C. for 5 minutes to obtain an iodine-based polarizing film (HF-01 ) The polarizing film had a width of 660 mm and a thickness of 20 μm on both sides.

(Preparation of polarizing plate)
Using a polyvinyl alcohol-based adhesive, KH-1 (optical compensation sheet) was attached to one side of the polarizing film (HF-01) on the support (PK-1) surface. Moreover, the saponification process was performed to the 80-micrometer-thick triacetyl-cellulose film (TD-80U: Fuji Photo Film Co., Ltd. product), and it affixed on the other side of the polarizing film using the polyvinyl alcohol-type adhesive agent.
The transmission axis of the polarizing film and the slow axis of the support (PK-1) were arranged in parallel. The transmission axis of the polarizing film and the slow axis of the triacetyl cellulose film were arranged so as to be orthogonal to each other. In this way, a polarizing plate (HB-1) was produced.

[Comparative Example 1]
An optical compensation sheet (KH-H1), and further a polarizing plate with KH-H1 (HB-), except that the fluoropolymer (P-15) is not added to the optically anisotropic layer, in the same manner as in Example 3. H1) was produced.

[Comparative Example 2]
An optical compensation sheet (KH-H2), and further a polarizing plate with KH-H2 (HB), except that the fluoropolymer (P-15) was changed to the following fluoropolymer (A), in the same manner as in Example 3. -H2) was prepared.

  Fluoropolymer (A): a copolymer of monomers (a-1) and (b-2-1) described in JP-A No. 11-148080.

[Example 4]
(Production of support)
Into the mixing tank, 16 parts by mass of the retardation increasing agent used in Example 1, 80 parts by mass of methylene chloride and 20 parts by mass of methanol were added and stirred while heating to prepare a retardation increasing agent solution.
25 parts by mass of the retardation increasing agent solution was mixed with 474 parts by mass of the cellulose acetate solution prepared in Example 1, and the dope was prepared by sufficiently stirring. The addition amount of the retardation increasing agent was 3.5 parts by mass with respect to 100 parts by mass of cellulose acetate.

The obtained dope was cast using a band casting machine. After the film surface temperature on the band reached 40 ° C., it was dried for 1 minute and peeled off, and then the support (PK-2) having a residual solvent amount of 0.3% by mass was dried with 140 ° C. drying air. Manufactured.
The obtained support (PK-2) had a width of 1500 mm and a thickness of 65 μm. It was 4 nm when the retardation value (Re) in wavelength 590nm was measured using the ellipsometer (M-150, JASCO Corporation make). Moreover, it was 78 nm when the retardation value (Rth) in wavelength 590nm was measured.

(Production of optical compensation sheet with optically anisotropic layer)
The support (PK-2) was immersed in a 2.0N potassium hydroxide solution (25 ° C.) for 2 minutes, neutralized with sulfuric acid, washed with pure water and dried. The surface energy of PK-2 was determined by a contact angle method and found to be 63 mN / m.
<Formation of alignment film>
On the produced PK-2, a coating solution having the following composition was coated with a # 16 wire bar coater at a coating amount of 28 ml / m ² . Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 90 ° C. for 150 seconds.

<Alignment film coating solution composition>
Modified polyvinyl alcohol of Example 1 10 parts by weight Water 371 parts by weight Methanol 119 parts by weight Glutaraldehyde (crosslinking agent) 0.5 parts by weight Next, modified polyvinyl alcohol to be oriented in a direction parallel to the longitudinal direction of PK-2 The membrane was rubbed.

<Formation of optically anisotropic layer>
Discotic liquid crystalline compound of Example 3 41.01 Kg
Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 4.06Kg
Cellulose acetate butyrate (CAB551-0.2, manufactured by Eastman Chemical Co.) 0.90Kg
Cellulose acetate butyrate (CAB531-1, manufactured by Eastman Chemical Co.) 0.23 kg
Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 1.35 kg
Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.45Kg

0.1 kg of a fluorine-containing polymer (P-79) was added to a solution obtained by dissolving the above compound in 102 kg of methyl ethyl ketone to form a coating solution, which was coated on the alignment film with a # 3.4 wire bar. This was heated in a constant temperature zone of 130 ° C. for 2 minutes to align the discotic liquid crystalline compound. Next, UV irradiation was performed for 1 minute using a 120 W / cm high-pressure mercury lamp in an atmosphere of 60 ° C. to polymerize the discotic liquid crystalline compound. Then, it stood to cool to room temperature.
Thus, an optically anisotropic layer was formed, and an optical compensation sheet (KH-2) was produced. The Re retardation value of the optically anisotropic layer measured at a wavelength of 546 nm was 40 nm.
The polarizing plate produced as described below was arranged in a crossed Nicol arrangement, and when the unevenness of the obtained optical compensation sheet was observed, the unevenness could not be detected even when viewed from the front and the direction inclined to 60 ° from the normal line.

(Preparation of polarizing plate)
Using a polyvinyl alcohol-based adhesive, KH-2 (optical compensation sheet) was attached to one side of the polarizing film (HF-01). Moreover, the saponification process was performed to the 80-micrometer-thick triacetyl-cellulose film (TD-80U: Fuji Photo Film Co., Ltd. product), and it affixed on the other side of the polarizing film using the polyvinyl alcohol-type adhesive agent.
The transmission axis of the polarizing film and the slow axis of PK-2 were arranged in parallel. The transmission axis of the polarizing film and the slow axis of the triacetyl cellulose film were arranged so as to be orthogonal to each other. In this way, a polarizing plate (HB-2) was produced.

[Comparative Example 3]
An optical compensation sheet (KH-H3) and a polarizing plate with KH-H3 (HB-H3) were produced in the same manner as in Example 4 except that the fluoropolymer was not added to the optically anisotropic layer. .

[Comparative Example 4]
An optical compensation sheet (KH-H4) and a polarizing plate with KH-H4 (HB) were used in the same manner as in Example 4 except that the fluoropolymer (P-79) was changed to the following fluoropolymer (B). -H4) was prepared.

  Fluoropolymer (B): Monomer (A-22) described in JP-A-2002-249706 and NK ester M-90G (polyethylene oxide chain-containing methacrylate (average number of added moles of ethylene oxide chain: 9), Shin-Nakamura Chemical Co., Ltd. Co., Ltd.)

[Example 5]
(Preparation of bend alignment liquid crystal cell)
A polyimide film was provided as an alignment film on a glass substrate with an ITO electrode, and the alignment film was rubbed. The obtained two glass substrates were faced to each other so that the rubbing directions were parallel to each other, and the cell gap was set to 6 μm. [Delta] n (refractive index difference between n _e and n _o) is a liquid crystal compound of 0.1396 (ZLI1132, manufactured by Merck) was injected to prepare a bend-aligned liquid crystal cell. The size of the liquid crystal cell was 20 inches.
Two polarizing plates (HB-1) prepared in Example 3 were attached so as to sandwich the manufactured bend alignment cell. The optically anisotropic layer of the elliptically polarizing plate was arranged so as to face the cell substrate, and the rubbing direction of the liquid crystal cell and the rubbing direction of the optically anisotropic layer facing it were antiparallel.
A rectangular wave voltage of 55 Hz was applied to the liquid crystal cell. A normally white mode of 2V white display and 5V black display was set. Using the measurement ratio (EZ-Contrast 160D, manufactured by ELDIM) with the transmittance ratio (white display / black display) as the contrast ratio, the viewing angle can be adjusted in 8 steps from black display (L1) to white display (L8). It was measured.
Moreover, the polarizing plate (HB-H1) produced in the comparative example 1 and the polarizing plate (HB-H2) produced in the comparative example 2 were each affixed by the same method, and the viewing angle was measured. As an evaluation measure of the viewing angle, the contrast ratio of the visual field image is maintained at 10 or more, and gradation inversion on the black side does not occur (that is, inversion occurs between the black display (L1) and the next level (L2)). None) A range of open angle values was used. The measurement results are shown in Table 1.

[Example 6]
(Evaluation of unevenness on LCD panel)
The display panels of the liquid crystal display devices of Example 3 and Comparative Examples 1 and 2 were all adjusted to halftone, and unevenness was evaluated. In Example 3, no unevenness was observed from any direction, but in Comparative Example 1, unevenness was detected in a lattice shape with an upper visual field of 45 ° or more. In Comparative Example 2, no unevenness was observed, but a spotted pattern was observed.

[Example 7]
(Evaluation with TN liquid crystal cell)
A pair of polarizing plates provided in a liquid crystal display device (AQUAS LC20C1S, manufactured by Sharp Corporation) using a TN type liquid crystal cell is peeled off, and the polarizing plate (HB-2) prepared in Example 4 is optically replaced. The compensation sheets (KH-2) were attached to the viewer side and the backlight side one by one through an adhesive so that the compensation sheet (KH-2) was on the liquid crystal cell side. The transmission axis of the polarizing plate on the observer side and the transmission axis of the polarizing plate on the backlight side were arranged so as to be in the O mode.
About the produced liquid crystal display device, the viewing angle was measured in eight steps from black display (L1) to white display (L8) using the measuring machine (EZ-Contrast 160D, ELDIM company make). The measurement results are shown in Table 2.
Moreover, the viewing angle of the polarizing plate (HB-H3) produced in Comparative Example 3 and the polarizing plate (HB-H4) produced in Comparative Example 4 was measured by the same method.

[Example 8]
(Evaluation of unevenness on LCD panel)
The display panels of the liquid crystal display devices of Example 4 and Comparative Examples 3 and 4 were all adjusted to halftone, and unevenness was evaluated. In Example 4, no unevenness was observed when viewed from any direction, but in Comparative Examples 3 and 4, unevenness was detected in a lattice pattern with an upper field of view of 45 ° or more.

  As is apparent from the results shown in Tables 1 and 2, when the fluorine-containing polymer of the present invention is added, it does not affect the viewing angle, and excellent surface uniformity is obtained. .

[Example 9]
(Production of optical compensation sheet with optically anisotropic layer)
A commercially available triacetyl cellulose film (Fuji Tac Fuji Photo Film Co., Ltd.) was immersed in a 2.0N potassium hydroxide solution (25 ° C.) for 2 minutes, neutralized with sulfuric acid, washed with pure water and dried. did. The surface energy was determined by a contact angle method and found to be 63 mN / m.
<Formation of alignment film>
A coating solution having the following composition was applied onto the Fuji Tac with a # 16 wire bar coater at a coating amount of 28 ml / m ² , and then heated at 60 ° C. for 60 seconds and then at 90 ° C. with warm air. Dry for 150 seconds.

<Alignment film coating solution composition>
Modified polyvinyl alcohol of Example 3 10 parts by weight Water 371 parts by weight Methanol 119 parts by weight Glutaraldehyde (crosslinking agent) 0.5 parts by weight Rubbing the modified polyvinyl alcohol film so as to be oriented in a direction parallel to the longitudinal direction of Fujitac Processing was carried out.

<Formation of optically anisotropic layer>
90 parts by mass of the discotic compound of Example 1 Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 10 parts by mass Melamine formaldehyde / acrylic acid copolymer (Aldrich reagent) 0.6 parts by mass Light Polymerization initiator (Irgacure 907, manufactured by Nippon Ciba Geigy Co., Ltd.) 3.0 parts by mass Photosensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1.0 part by mass is dissolved in methyl ethyl ketone to obtain a solid content. A solution having a concentration of 38% by mass was prepared, and 3.6 parts by mass of a fluoropolymer (P-11) was added to the solution to prepare a coating solution.

This coating solution was applied onto the alignment film at the same coating amount as in Example 2 and dried. The discotic compound was oriented by heating at 130 ° C. for 1 minute. Immediately cooled to room temperature, irradiated with 500 mJ / cm ² of ultraviolet rays to polymerize the discotic compound, fix the alignment state, and produce an optical compensation sheet (KH-3). The thickness of the formed optically anisotropic layer was 1.7 μm.
The angle dependence of retardation of the optically anisotropic layer was measured with an ellipsometer (manufactured by JASCO Corporation). As a result, the angle between the disc surface of the discotic compound and the alignment film surface was 0.2 °, and the retardation (Rth) in the thickness direction was 150 nm.

(Preparation of polarizing plate)
An optical compensation sheet (KH-3) was attached to one side of the polarizing film (HF-01) using a polyvinyl alcohol-based adhesive. Moreover, the saponification process was performed to the 80-micrometer-thick triacetyl-cellulose film (TD-80U: Fuji Photo Film Co., Ltd. product), and it affixed on the other side of the polarizing film using the polyvinyl alcohol-type adhesive agent.
The transmission axis of the polarizing film (HF-01) and the slow axis of KH-3 were arranged in parallel. The transmission axis of the polarizing film and the slow axis of the triacetyl cellulose film were arranged so as to be orthogonal to each other. In this way, a polarizing plate (HB-3) was produced.

[Comparative Example 5]
Except that the fluoroalkyl group-containing monomer (P-11) is not added to the optically anisotropic layer, the optical compensation sheet (KH-H5), and further the polarizing plate with KH-H5 ( HB-H5) was prepared.

[Comparative Example 6]
An optical compensation sheet (KH-H6), and further a polarizing plate with KH-H6 (HB-), except that the fluoropolymer (P-11) was changed to the following fluoropolymer (C), in the same manner as in Example 9. H6) was produced.

  Fluorine-containing polymer (C): a polymer (polymer 1-1) described in JP-A-2002-249706, PR Example (Reference Example 1).

[Example 10]
(Vertical alignment type liquid crystal cell)
A pair of polarizing plates and a pair of retardations provided in a liquid crystal display device (VL-1530S, manufactured by Fujitsu Limited) using a vertical alignment type liquid crystal cell were peeled off, and the polarizing plate prepared in Example 9 ( HB-9) was affixed via an adhesive so that Fuji Tac was on the liquid crystal cell side. The crossed Nicols were arranged so that the transmission axis of the polarizing plate on the viewer side was in the vertical direction and the transmission axis of the polarizing plate on the backlight side was in the horizontal direction.
Further, a liquid crystal display device incorporating the polarizing plate (HB-H5) manufactured in Comparative Example 5 and the polarizing plate (HB-H6) manufactured in Comparative Example 6 was manufactured in the same manner.

[Example 11]
(Evaluation of unevenness on the panel)
The liquid crystal display device including the polarizing plate produced in Example 9 and Comparative Examples 5 and 6 was adjusted to a halftone on the entire surface, and unevenness was evaluated. In the case of including the polarizing plate prepared in Example 9, no unevenness was observed from any direction. However, in the case of including the polarizing plate prepared in Comparative Example 5, when the field of view was tilted by 45 °, all directions were observed. Unevenness was detected in a grid pattern. Further, the alignment of the liquid crystal was not uniform when the polarizing plate produced in Comparative Example 6 was included.

  From this, it is clear that when the fluorine-containing polymer of the present invention is added, excellent surface uniformity can be obtained without affecting the alignment of the liquid crystal.

Claims (7)

In an optical film having an optical functional layer on a transparent support, at least one layer of the optical functional layer includes a repeating unit derived from the following monomer (i) and a repeating unit derived from the following monomer (ii): An optical film comprising a fluorine-containing polymer whose content exceeds 50% by mass of the total polymerization units.
(I) A fluoroalkyl group-containing monomer represented by the following general formula [1].
(Ii) A fluoroalkyl group-containing monomer represented by the following general formula [2].
General formula [1]

General formula [2]

In the formula, R ¹ and R ² each independently represents a hydrogen atom, a methyl group or a halogen atom. L ¹ and L ² each independently represent a divalent group, and m and n each independently represent an integer of 1 to 12. The optical film according to claim 1, wherein the fluoropolymer further has a repeating unit derived from the monomer (iii) below.
(Iii) A monomer copolymerizable with the monomers (i) and (ii).   3. The optical film according to claim 1, wherein at least one of the optical functional layers containing the fluoropolymer is an optically anisotropic layer formed from a liquid crystal compound.   The optical film according to claim 3, wherein the liquid crystal compound is a discotic compound.   A polarizing plate comprising the optical film according to claim 1.   The optical film as described in any one of Claims 1-4 is used for one of the two protective films of the polarizing film in a polarizing plate, The polarizing plate characterized by the above-mentioned.   An image display device comprising the optical film according to claim 1.