JP2007101658A - Optical film, polarizing plate using the same and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for optically compensating a liquid crystal cell by using a polarizing plate having an optical compensation function, and an optical film used therefor, especially, to provide a method for displaying a high-quality image without causing drying unevenness and stripe irregularity even in a large-size liquid crystal display device and an optical film used therefor, and to provide a liquid crystal display device using the optical film or the polarizing plate. <P>SOLUTION: The optical film has an optically anisotropic layer containing a fluorine-containing polymer and a liquid crystal compound on a substrate. The optical film is characterized in that the fluorine-containing polymer is included in the optically anisotropic layer by 0.137 mass% and the surface tension S of MEK solution with respect to air is in the range of 21.0 to 22.0 mN/m. Further, the polarizing plate and the liquid crystal display device using the optical film are disclosed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical film, particularly an optical film having an optical compensation function that does not cause unevenness even in a large liquid crystal display device, and a polarizing plate and a liquid crystal display device using the optical film.

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 technological advances in the optical compensation film of the device are remarkable.
The liquid crystal display device includes a polarizing plate and a liquid crystal cell.
In the TN mode TFT liquid crystal display device which is currently mainstream, an optical compensation sheet is inserted between the polarizing plate and the liquid crystal cell to realize a liquid crystal display device with high display quality. However, this method has a problem that the liquid crystal display device itself becomes thick.

According to Patent Document 1, it is possible to increase the front contrast without increasing the thickness of the liquid crystal display device by using an elliptically polarizing plate having a retardation film on one side of the polarizing film and a protective film on the other side. There is a description. However, the retardation film (optical compensation sheet) of the present invention has a problem that a sufficient viewing angle improvement effect cannot be obtained and the display quality of the liquid crystal display device is lowered.
In the inventions described in Patent Documents 2 and 3, an optical compensation sheet obtained by coating an optically anisotropic layer formed of a discotic compound on a transparent support is directly used as a protective film for a polarizing plate. The problem with viewing angle was solved without making the liquid crystal display thick.

In the prior art, an optical compensation sheet has been developed mainly assuming a small or medium-sized liquid crystal display device of 15 inches or less. However, recently, it is also necessary to assume a liquid crystal display device having a large size of 17 inches or more and high brightness.
When a conventional optical compensation sheet was mounted as a protective film on a polarizing plate of a large liquid crystal display device, it was found that unevenness occurred on the panel. Although this defect was not so noticeable in small or medium-sized liquid crystal display devices, it became more noticeable in response to the increase in size and brightness, and it was necessary to further develop an optical film that coped with uneven light leakage. .
Patent Document 4 discloses a technique for improving unevenness by incorporating a leveling agent into a polymerizable liquid crystal, but this technique is effective only when the polymerizable liquid crystal is homogeneously aligned, and is a hybrid alignment. It was found that it cannot be applied to complicated orientations such as.
In addition to the above-described prior arts, Patent Document 5 discloses a method for reducing unevenness in display by including a polymer composed of a fluoroaliphatic-containing monomer and a (meth) acrylic monomer in an optically anisotropic layer. And a remarkable effect was observed. However, recent market-oriented demands require a further increase in the size of the display screen, and therefore, further reduction of display screen unevenness, particularly elimination of unevenness, is required for reduction of display unevenness.

JP-A-1-68940 Japanese Patent Laid-Open No. 7-191217 European Patent 0911656A2 JP-A-11-148080 JP 2004-198511 A

The present invention has been made from the above background, and therefore the object thereof is to provide an optical film having an optically anisotropic layer with improved image display quality, especially in a large liquid crystal display device. Another object of the present invention is to provide a method for displaying an image with high display quality without causing unevenness on the display screen, in particular, unevenness in drying and unevenness, and an optical film used therefor.
Moreover, it is providing the polarizing plate and liquid crystal cell which have the optical compensation function by which the display quality was improved using the optical film.

  As a result of intensive studies based on the technique of Patent Document 5 in order to find further means for reducing display unevenness, the present inventor obtained MEK (methyl ethyl ketone) as a composition of the optically anisotropic layer. If the surface tension of the solution dissolved in a certain concentration is within a specific range, the optical film having the anisotropic layer is found to have less drying unevenness and unevenness, and the present invention has been reached based on this finding. . That is, an object of the present invention is to provide an optical film of the following (1) to (8) and a production method thereof, a polarizing plate of the following (9) provided with the optical film, and a liquid crystal display of the following (10) composed thereof Achieved by the device.

(1) In an optical film having an optically anisotropic layer containing a fluoropolymer and a liquid crystal compound on a support, the surface tension of a 0.137% by mass MEK solution of the composition of the optically anisotropic layer is 21.0. [mN / m] or more and 22.0 [mN / m] or less.
(2) The optical film as described in (1) above, wherein the fluorine-containing polymer is a copolymer.
(3) The optical film as described in any one of (1) to (4) above, wherein the fluoropolymer has a hydrophilic monomer as a constituent monomer component.
(4) The optical film as described in any one of (1) to (5) above, which has an alignment film on a support and is coated with an optical anisotropic layer on the alignment film.
(5) In an optical film having an optically anisotropic layer containing a fluorine-containing polymer and a liquid crystal compound on a support, the optically anisotropic layer is derived from a monomer of the following (i) and the following (ii) The optical film according to any one of the above (1) to (4), comprising a fluoroaliphatic group-containing copolymer containing a structural unit derived from the monomer (1).
(I) Fluoroaliphatic group-containing monomer represented by the following general formula [1] (ii) Poly (oxyalkylene) acrylate and / or poly (oxyalkylene) methacrylate General formula [1]

(In the general formula [1], R ₁ represents a hydrogen atom or a methyl group, X represents an oxygen atom, a sulfur atom or —N (R ₂ ) —, m is an integer of 1-6, and n is 2-4. R ₂ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

(6) In an optical film having an optically anisotropic layer containing a fluoropolymer and a liquid crystal compound on a support, the optically anisotropic layer is a repeating unit derived from the monomer (i) below, (ii Any one of (1) to (5) above, comprising a fluoroaliphatic group-containing copolymer comprising a repeating unit derived from the monomer (ii) and a repeating unit derived from the monomer (iii) below: The optical film described in 1.
(I) the fluoroaliphatic group-containing monomer represented by the general formula [1] described in (5) above (ii) poly (oxyalkylene) acrylate and / or poly (oxyalkylene) methacrylate (iii) (i) above And a monomer represented by the following general formula [2] copolymerizable with (ii):

(In the general formula [2], R ₃ represents a hydrogen atom or a methyl group, Y represents a divalent linking group, R ₄ represents a straight chain having 4 to 20 carbon atoms which may have a substituent, Represents a branched or cyclic alkyl group.)

(7) The optical film as described in any one of (1) to (6) above, wherein the liquid crystal compound is a discotic compound.
(8) An optically anisotropic layer containing a fluorine-containing polymer and a liquid crystal compound is coated on the alignment film on the support to obtain the optical film according to any one of the above (1) to (7). A method for producing an optical film.
(9) A polarizing plate comprising the optical film according to any one of (1) to (7).
(10) A liquid crystal display device comprising the optical film according to any one of (1) to (7) above.

  The surface tension of a 0.137% by mass MEK solution of a fluorine-containing polymer in the composition of the optically anisotropic layer is 21.0 [mN / m] or more and 22.0 [mN / m] or less. By using the optical film of the present invention, a liquid crystal cell can be optically compensated effectively, and even in a large-sized liquid crystal display device, an image with high display quality can be obtained without causing unevenness, in particular, dry unevenness and uneven stripes. Can be displayed. Therefore, an uneven polarizing plate and a liquid crystal display device using this optical film can be provided.

  The optical film of the present invention is characterized in that the surface tension of a 0.137% by mass MEK solution of a fluorine-containing polymer in the composition of the optically anisotropic layer is 21.0 [mN / m] or more and 22.0 [mN / m] or less, and an optical film having an optical compensation layer having a composition having a surface tension within this range has unevenness caused by an optical film in which an optical compensation sheet and a polarizing plate are combined, particularly unevenness. Can be suppressed. In addition, by applying the optical film to a large-sized liquid crystal display device, even a large area display does not cause unevenness, and an image with high display quality can be displayed.

The fluorine-containing polymer in the composition of the optically anisotropic layer literally refers to the fluorine-containing polymer in the solid component constituting the optically anisotropic layer, but the fluorine-containing polymer before being incorporated into the composition in terms of surface tension measurement. It is substantially the same as the polymer.
When the fluorine-containing polymer in the composition of the optically anisotropic layer is dissolved in MEK to obtain a 0.137% by mass solution, the surface tension of the solution is 21.0 [mN / m] or more and 22.0 [mN at 25 ° C. / m] or less, and within this range, the reduction in unevenness, which is an effect of the invention, is remarkable. A more preferable surface tension is 21.4 [mN / m] or more and 21.7 [mN / m] or less.
When the value of the surface tension exceeds the preferable range, the coating property is deteriorated, and streaks unevenness and drying unevenness are increased. On the other hand, if it is lower than the preferred range, it becomes unsuitable due to uneven stripes or uneven drying.

In this specification, the surface tension refers to the surface tension at 25 ° C. unless otherwise specified. Of course, the surface tension is the surface tension with air as the contact surface. Further, in a place where there is no possibility of misunderstanding, the “surface tension of the fluorine-containing polymer 0.137 mass% MEK solution” may be simply referred to as “surface tension of the fluorine-containing polymer solution”.
The surface tension measurement described in this specification uses an automatic surface tension meter CBVP-Z type (manufactured by Kyowa Marine Science Co., Ltd.), the measurement mode is the blade method, fully automatic, and the sample concentration is as described above. It is a 0.137 mass% MEK solution, and the amount of the sample is 15 g.
However, the apparatus and method for measuring the surface tension are not limited as long as the surface tension of the MEK solution of the fluoropolymer can be measured at the above concentration.

Hereinafter, the optically anisotropic layer used in the present invention will be described first from the fluorine-containing polymer.
[Fluoropolymer]
As long as the fluorine-containing polymer used in the present invention is a polymer that can be contained in the optically anisotropic layer and contains a fluorine element in the constituent component, as long as it has the molecular weight configuration described above, and as long as it is in the range of the constituent composition amount described above, It can be used without limitation. In the present invention, the molecular weight composition is determined by GPC (gel permeation chromatography) analysis. As the measurement conditions, a 0.201% by mass THF solution of a fluorine-containing polymer was used, and polystyrene having a molecular weight of 1090000, 706000, 427000, 190000, 96400, 37900, 800, 10200, 5970, 2630, 1050,500 was selected as the standard sample. However, it is preferable to use a TSK gel column. The fluorine-containing polymer constituent amount is indicated by a development area ratio.
Among the fluorine-containing polymers, a copolymer having a fluoroaliphatic group (sometimes abbreviated as “fluorine polymer”) is preferable. Hereinafter, the fluoropolymer will be described in detail.
Among the above-mentioned fluorine-containing polymers, a copolymer having a fluoroaliphatic-containing structure and a poly (oxyalkylene) acrylate or methacrylate structure particularly exhibits the effects of the present invention. This fluoroaliphatic-containing copolymer further improves the effect of the present invention by adjusting the optical characteristics by adding a monomer represented by the general formula [II] as a copolymerization component, and is compatible with a liquid crystal display device. Can be adjusted.

  As the fluorine-based polymer preferably used in the present invention, an acrylic resin, a methacrylic resin, and a copolymer with a vinyl monomer copolymerizable therewith satisfying the requirements described in the above (1) or (2) are useful. .

  One of the fluoroaliphatic groups in the fluoropolymer according to the present invention is derived from a fluoroaliphatic compound produced by a telomerization method (also referred to as a telomer method) or an oligomerization method (also referred to as an oligomer method). It is. Regarding the production method of these fluoroaliphatic compounds, for example, “Synthesis and function of fluorine compounds” (supervision: Nobuo Ishikawa, published by CMC Co., 1987), “Chemistry of Organic Fluorine Compounds” II "(Monograph 187, Milos Hudlicky and Attila E. Pavlath, American Chemical Society 1995), pages 747-752. The telomerization method is a method of synthesizing a telomer by radical polymerization of a fluorine-containing vinyl compound such as tetrafluoroethylene using an alkyl halide having a large chain transfer constant such as iodide as a telogen (example in Scheme-1). showed that).

  The obtained terminal iodinated telomer is usually subjected to appropriate terminal chemical modification such as [Scheme2], and led to a fluoroaliphatic compound. These compounds are further converted into a desired monomer structure as necessary, and used for the production of a fluoroaliphatic group-containing polymer.

In the general formula [1] of the present invention, R ₁ represents a hydrogen atom or a methyl group, and X represents an oxygen atom, a sulfur atom, or —N (R ₂ ) —. Here, R ₂ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, specifically a methyl group, an ethyl group, a propyl group, or a butyl group, preferably a hydrogen atom or a methyl group. X is more preferably an oxygen atom.
M in the general formula [1] is preferably an integer of 1 to 6 and particularly preferably 2.
In the general formula [1], n is 2 to 4, particularly 2 or 3, and a mixture thereof may be used.
Although the example of the more specific monomer of the fluoro aliphatic group containing monomer represented by General formula [1] is given below, it is not this limitation.

In the general formula [2], R ₃ represents a hydrogen atom or a methyl group, and Y represents a divalent linking group. As the divalent linking group, an oxygen atom, a sulfur atom or —N (R ₅ ) — is preferable. R ₅ is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, a propyl group, or a butyl group. More preferred forms of R ₅ are a hydrogen atom and a methyl group.
Y is more preferably an oxygen atom, —N (H) —, and —N (CH ₃ ) —.
R ₄ represents a linear, branched or cyclic alkyl group having 4 to 20 carbon atoms which may have a substituent. Examples of the substituent for the alkyl group of R ₄ include a hydroxyl group, an alkylcarbonyl group, an arylcarbonyl group, a carboxyl group, an alkyl ether group, an aryl ether group, a halogen atom such as a fluorine atom, a chlorine atom, and a bromine atom, a nitro group, and a cyano group. , Amino groups and the like, but not limited thereto. Examples of the linear, branched or cyclic alkyl group having 4 to 20 carbon atoms include a butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group and undecyl group which may be linear or branched. , Dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, octadecyl group, eicosanyl group, etc., and monocyclic cycloalkyl groups such as cyclohexyl group, cycloheptyl group and bicycloheptyl group, bicyclodecyl group, tricycloundecyl group, A polycyclic cycloalkyl group such as a tetracyclododecyl group, an adamantyl group, a norbornyl group, or a tetracyclodecyl group is preferably used.

  Specific examples of the monomer represented by the general formula [2] include, but are not limited to, the following monomers.

Next, poly (oxyalkylene) acrylate and / or poly (oxyalkylene) methacrylate, which are essential components of the optically anisotropic layer constituting the optical film of the present invention, will be described (hereinafter, when referring to both acrylate and methacrylate, both May be collectively referred to as (meth) acrylate).
Polyoxyalkylene 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 is the number of repeated oxyalkylene groups, preferably 2 to 30, more preferably 3 to 25, and most preferably 4 to 20.
The oxyalkylene units in the poly (oxyalkylene) group may be the same as in the poly (oxypropylene) group, or two or more different oxyalkylene units may be randomly distributed. It may be a linear or branched oxypropylene unit or oxyethylene unit, or may be present as a block of linear or branched oxypropylene units and a block of oxyethylene units.
In this poly (oxyalkylene) chain, a plurality of poly (oxyalkylene) units are linked to each other by one or more chain bonds (for example, -CONH-Ph-NHCO-, -S-, etc., where Ph represents a phenylene group) ) Can be included. If the chain bond has a valence of 3 or more, this provides a means for obtaining branched oxyalkylene units. When this copolymer 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 Product)), "Triton" (Toriton (Rohm and Haas)) and "PEG" (Daiichi Kogyo Seiyaku Co., Ltd.) Can be produced by reacting the product with acrylic acid, methacrylic acid, acrylic chloride, methacrylic chloride or acrylic acid anhydride in a known manner.
Separately, poly (oxyalkylene) diacrylate produced by a known method can also be used.

A copolymer of the monomer represented by the general formula [1], which is an essential component of the optically anisotropic layer used in the present invention, and polyoxyalkylene (meth) acrylate is used. It is preferable to include.
A particularly preferred embodiment is a polymer obtained by copolymerizing three or more monomers of the monomer represented by the general formula [1], polyoxyethylene (meth) acrylate, and polyoxyalkylene (meth) acrylate. Here, polyoxyalkylene (meth) acrylate is a monomer different from polyoxyethylene (meth) acrylate.
More preferably, it is a terpolymer of polyoxyethylene (meth) acrylate, polyoxypropylene (meth) acrylate, and a monomer represented by the general formula [1].
A preferable copolymerization ratio of polyoxyethylene (meth) acrylate is 0.5 mol% or more and 20 mol% or less, more preferably 1 mol% or more and 10 mol% or less in all monomers.

A copolymer of the monomer represented by the general formula [1] and the monomer represented by poly (oxyalkylene) acrylate and / or poly (oxyalkylene) methacrylate and the general formula [2] used in the present invention is In addition to the monomer, a copolymer obtained by adding a monomer copolymerizable with these and reacting them may also be used.
A preferable copolymerization ratio of the copolymerizable monomer is 20 mol% or less, more preferably 10 mol% or less, based on all monomers.
Such monomers include Polymer Handbook 2nd edition, J. MoI. Brandrup, Wiley lnterscience (1975), Chapter 2, pages 1-483 can be used.
For example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid, methacrylic acid, acrylic esters, methacrylic esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. I can give you.

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

Acrylamides:
Acrylamide, N-alkyl acrylamide (alkyl group having 1 to 3 carbon atoms, such as methyl group, ethyl group, propyl group), N, N-dialkyl acrylamide (alkyl group having 1 to 3 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, for example, methyl group, ethyl group, propyl group), N, N-dialkylmethacrylamide (alkyl group having 1 to 3 carbon atoms) ), N-hydroxyethyl-N-methylmethacrylamide, N-2-acetamidoethyl-N-acetylmethacrylamide and the like.
Allyl compounds:
Allyl esters (for example, allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, etc.), allyloxyethanol and the like.

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 and the like.
Vinyl esters:
Vinyl bubilate, 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 esters or monoalkyl esters of fumaric acid: dibutyl fumarate and the like.
In addition, crotonic acid, itaconic acid, acrylonitrile, methacrylonitrile, maleilonitrile, styrene, etc.

  In addition, some of the fluorinated 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. There are concerns about toxicity and developmental toxicity. It can be said that it is an industrial advantage that the fluoropolymer according to the present invention is a more environmentally safe substance.

The amount of the fluoroaliphatic group-containing monomer represented by the general formula [1] in the fluoropolymer used in the present invention is 5 mol% or more, preferably 5 to 70 mol%, based on the total amount of constituent monomers of the polymer. More preferably, it is the range of 7-60 mol%.
The amount of poly (oxyalkylene) acrylate and / or poly (oxyalkylene) methacrylate, which is an essential component in the fluoropolymer of the present invention, is 10 mol% or more of the total amount of constituent monomers of the fluoropolymer, preferably 15 It is -70 mol%, More preferably, it is 20-60 mol%.
The amount of the monomer represented by the general formula [2], which is a form preferably used for the fluoropolymer of the present invention, is 3 mol% or more, preferably 5 to 50 mol% of the total amount of constituent monomers of the fluoropolymer. More preferably, it is 10-40 mol%.

The preferred weight average molecular weight of the fluoropolymer used in the present invention is preferably 3000 to 100,000, more preferably 6,000 to 80,000.
Furthermore, the preferable content of the fluoropolymer according to the present invention with respect to the coating composition mainly comprising a liquid crystal compound (coating component excluding the solvent) is in the range of 0.005 to 8% by mass, preferably 0.01. It is the range of -1 mass%, More preferably, it is the range of 0.05-0.5 mass%. If the addition amount of the fluorine-based polymer is less than 0.005% by mass, the effect is insufficient, and if it exceeds 8% by mass, the coating film may not be sufficiently dried or the performance as an optical film (for example, retardation) Adverse effects on the uniformity of

These fluoropolymers have a molecular weight distribution similar to general polymer compounds. In general, a so-called monodisperse polymer having a narrow molecular weight distribution is preferred, but in the present invention, a fluorine-containing polymer having a weight average molecular weight of 3000 to 100,000 is intentionally incorporated with 8% or more of a fluoropolymer component having a weight average molecular weight of 100,000 or more. In addition, by suppressing the component having a weight average molecular weight of 20000 or less to 61% or less, or by implementing both of them, an optical film with improved unevenness and unevenness was realized.
Adjustment of molecular weight components such as a high molecular weight component and a low molecular weight component was performed by molecular weight fractionation using GPC or the like.

  The fluoropolymer used in the present invention can be produced by a known and conventional method. For example, a general-purpose radical polymerization initiator is added and polymerized in an organic solvent containing monomers such as (meth) acrylate having a fluoroaliphatic group and (meth) acrylate having a polyoxyalkylene group. Can be manufactured. Further, in some cases, other addition-polymerizable unsaturated compounds can be further added and produced by the same method 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.

  Hereinafter, although the example of the specific structure of the fluorine-type polymer used by this invention is shown, this invention is not limited to these. In addition, the number in a formula shows the molar ratio of each monomer component. Mw represents a weight average molecular weight.

[Optically anisotropic layer]
In the present invention, the fluorine-containing polymer contained in the optically anisotropic layer has already been described. The configuration of the other optically anisotropic layer and the layer forming method will be described.
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 crystalline 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 a 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 is preferably 25 mN / m or less, and more preferably 22 mN / m or less.
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)
As rod-like liquid crystalline molecules, 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 Chemical Chemistry of the Quarterly Chemical Review Vol. 22, Liquid Crystal Chemistry (1994), and the 142nd 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, A78, 82 (1990)). 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 from 4 to 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 (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 valent 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 to 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 the formula (III), n is an integer of 4 to 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.

  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, but another polymer may be used together with the discotic compound, and the polymer may be combined with the discotic compound to some extent. It is preferable that the discotic compound can be changed in inclination angle.
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 amount of the polymer added is preferably in the range of 0.1 to 10% by mass and preferably 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 aromatic acyloin. Compound (described in US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) Acridine and phenazine compounds (JP-A-60-105667, U.S. Pat. No. 4,239,850) and oxadiazole compounds (U.S. Pat. No. 4,212,970).

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.
Light irradiation for polymerizing liquid crystalline molecules is preferably performed using ultraviolet rays.
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.
Alternatively, 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, general-purpose polarizers are 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. The introduction of the crosslinked structure can be formed by introducing a bonding group derived from the crosslinking agent between the binders using a crosslinking agent that is a highly reactive compound and crosslinking between the binders.
Crosslinking is generally carried out by applying a coating solution 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, carboxymethylcellulose, 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 95 to 100%. The polymerization degree of polyvinyl alcohol is preferably 100 to 5000.
The 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, groups such as COONa, Si (OH) ₃ , N (CH ₃ ) ₃ .Cl, C ₉ H ₁₉ COO, SO ₃ Na, and C ₁₂ H ₂₅ can be introduced as modifying groups. . In chain transfer modification, groups such as COONa, SH, and SC ₁₂ H ₂₅ can be introduced as modifying groups. 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 preferred.
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. The addition amount of the crosslinking agent is preferably 0.1 to 20% by mass, and more preferably 0.5 to 15% by mass with respect to the binder.
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 that is blended with various dichroic molecules so as to exhibit a black color, have both a single-plate transmittance and a polarizing coefficient. 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 by tilting the binder 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 °. However, recently, liquid crystal display 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 by different stretching operations. 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, the angle is preferably 40 to 50 °. 45 ° is particularly preferred.
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).

Hereinafter, constituent materials necessary for the optical film 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 triacetate, 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). Cellulose acetate is particularly preferred. Mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate may be used.

Even in the case of polymers that are easily known to exhibit birefringence, such as polycarbonate and polysulfone, which are conventionally known, the birefringence can be developed by modifying the molecule as described in WO '00 / 26705. Can be used for the optical film of the present invention.
When the optical film of the present invention is used for a polarizing plate protective film or a retardation film, cellulose acetate having an acetylation degree of 55.0 to 62.5% is preferably used as the polymer film. The acetylation degree is more preferably 57.0 to 62.0%.

The degree of acetylation means the mass of bound acetic acid per mass of glucopyranose unit. 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 described in Synthesis Example 1 described in Paragraph Nos. 0043 to 0044, Synthesis Example 2 described in Paragraph Nos. 0048 to 0049, and Paragraph Nos. 0051 to 0052. It can be synthesized with reference to the method of Synthesis Example 3.

[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 crystalline molecules rise at the center of the cell and the rod-like liquid crystalline molecules lie in the vicinity of the cell substrate.

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

(Transparent) 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 a homeotropically oriented discotic compound and The optically anisotropic layer comprising a homogeneously aligned rod-like liquid crystal molecule mixture preferably has an Rth retardation value of 40 nm to 200 nm and an Re retardation value of 0 to 70 nm.
In this specification, Re and Rth respectively represent in-plane retardation and retardation in the thickness direction at a wavelength λ. Re is measured by making light having a wavelength of λ nm incident in the normal direction of the film in an automatic birefringence meter such as KOBRA 21ADH (manufactured by Oji Scientific Instruments). Rth was measured by making light having a wavelength λ nm incident from a direction inclined + 40 ° with respect to the film normal direction with the Re, in-plane slow axis (determined by KOBRA 21ADH) as the tilt axis (rotation axis). The retardation value and the retardation value measured by making light of wavelength λ nm incident from a direction inclined by −40 ° with respect to the film normal direction with the in-plane slow axis as the tilt axis (rotation axis). An automatic birefringence meter such as KOBRA 21ADH is calculated based on the retardation value measured in the direction. Here, as the assumed value of the average refractive index, the values in the polymer handbook (JOHN WILEY & SONS, INC) and catalogs of various optical films can be used. Those whose average refractive index is not known can be measured with an Abbe refractometer. The average refractive index values of the main optical films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), Polystyrene (1.59). KOBRA 21ADH calculates nx, ny, and nz by inputting these assumed values of average refractive index and film thickness.
Regarding the discotic liquid crystalline molecular layer having homeotropic alignment (horizontal alignment) and the rod-like liquid crystalline molecular layer having homogeneous alignment (horizontal alignment), JP-A-12-304931 and JP-A-12-304932 describe each of them. Are listed. 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)
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 an upper portion and a lower portion 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 such that the rod-like liquid crystal molecules rise in 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 (transparent) support is homeotropically oriented, or the optically anisotropic layer in which the rod-like liquid crystalline molecules are homogeneously oriented is Rth retardation. The value is preferably 150 nm to 500 nm, and the 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 crystalline molecules are aligned substantially vertically when no voltage is applied.
The VA mode liquid crystal cell includes (1) a narrowly defined VA mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied, and substantially horizontally when a voltage is applied (Japanese Patent Laid-Open No. Hei 2-). 176625) (2) Liquid crystal cell (SID97, Digest of tech. Papers (Preliminary Proceed) 28 (1997) 845 in which the VA mode is made into a multi-domain (MVA mode) for widening the viewing angle ), (3) 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 Japanese Liquid Crystal Society) (1998)) and (4) SURVAVAL 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 °.
(Transparent) 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. And the Re 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.

[Example 1]
(Production of polymer substrate)
In the following examples, the following polymer substrate was used as a 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 with 60.9% acetylation (from linter material) 80 parts by weight Cellulose acetate with 60.8% acetylation (from linter material) 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

In a separate mixing tank, 4 parts by mass of cellulose acetate having an acetylation degree of 60.9% (based on linter), 16 parts by mass of the following retardation increasing agent, silica fine particles (particle size 20 nm, Mohs hardness about 7) 0.5 parts by mass, 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.
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, the width of the film was 28 in the width direction using a tenter with a drying air of 140 ° C. % Stretched. Then, it dried with 135 degreeC dry air for 20 minutes, and manufactured the polymer base material (PK-1) whose residual solvent amount is 0.3 mass%.
The obtained polymer substrate (PK-1) had a width of 1340 mm and a thickness of 92 μm. When the retardation value (Re) at a wavelength of 590 nm was measured using an automatic birefringence meter (KOBRA21ADH, manufactured by Oji Scientific Instruments), it was 43 nm. Moreover, it was 175 nm when the retardation value (Rth) in wavelength 590nm was measured.
The produced polymer substrate (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.

(Orientation film coating solution composition)
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 polymer substrate (PK-1).

(Formation of optically anisotropic layer)
The following discotic liquid crystalline compound 41.01 kg, ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 4.06 kg, cellulose acetate butyrate (CAB531-1, manufactured by Eastman Chemical Co., Ltd.) ) 0.35 kg, photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 1.35 kg, and sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.45 kg are dissolved in 102 kg of methyl ethyl ketone. The solution further contains a fluoroaliphatic group-containing copolymer (in this example, Megafac F780 Dainippon Ink Co., Ltd.) is subjected to an operation such as molecular weight fractionation to change the molecular weight distribution, and the molecular weight is 10,000 or more. Use a sample with a molecular weight distribution (sample 1) with a ratio of 12.8% and a ratio of 20,000 or less of 63.9%) Add 0.1 kg to make a coating solution. This coating solution is continuously applied onto the alignment film with a # 3.6 wire bar and heated at 130 ° C. for 2 minutes to align the discotic liquid crystalline compound. It was. Next, UV irradiation was performed for 1 minute using a 120 W / cm high-pressure mercury lamp at 100 ° C. to polymerize the discotic liquid crystalline compound. Then, it stood to cool to room temperature. In this way, an optical compensation sheet (KH1) 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 angle (tilt angle) between the disk surface and the first transparent support surface was 33 ° on average.
When the polarizing plate was arranged in a crossed Nicol arrangement and 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.
In accordance with the same method as above, however, a fluoroaliphatic group-containing copolymer (in the present invention, a product made by Megafac F780 Dainippon Ink Co., Ltd.) was subjected to operations such as molecular weight fractionation, and the molecular weight distribution as shown in Table 1. The optical compensation sheets KH2 to KH7 having different molecular weight distributions as described below were prepared by the molecular weight fractionation operation. That is, Sample 2 has a molecular weight of 10,000 or more at 8.7%, 20,000 or less at 65.0%, and Sample 3 has a molecular weight of 10,000 or more at 10.1% or 20,000 or less. 65.2%, sample 4 has a molecular weight of 10,000 or more at 10.5%, 20,000 or less at 65.9%, and sample 5 has a molecular weight of 10,000 or more at 11.3%, 2 The ratio of the molecular weight of 10,000 or less is 64.5%, the sample 6 has a molecular weight of 10,000 or more of 13.5%, the ratio of 20,000 or less of 64.7%, and the sample 7 has a molecular weight of 10,000 or more of 8. The ratio of 7% or 20,000 or less is 64.2%. Samples 2 to 7 are fluoropolymer samples used for KH2 to KH7, respectively.

The surface tension of the fluoropolymer solution was measured by the following method.
First, a 0.137% by mass MEK solution in which 0.137 g of a fluoropolymer and 99.863 g of MEK were sufficiently mixed and made uniform was prepared.
Next, 15g of fluoropolymer 0.137 mass% MEK solution was sampled and used as a sample for surface tension measurement. Automatic surface tension meter CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) was used, and the measurement mode was blade method. As a result, surface tension was measured automatically.

(Production of polarizer)
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, immersed in an aqueous solution of 60 g / L of potassium iodide 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 polarizer (HF-01 ) The polarizer had a width of 660 mm and a thickness of 20 μm on both the left and right sides.

(Preparation of polarizing plate)
Each of the optical compensation sheets (KH1 to KH7) was attached to one side of the polarizer (HF-1) on the polymer substrate (PK-1) surface using a polyvinyl alcohol-based adhesive. Moreover, the saponification process was performed to the 80-micrometer-thick triacetylcellulose film (TD-80U: Fuji Photo Film Co., Ltd. product), and it affixed on the other side of the polarizer using the polyvinyl alcohol-type adhesive agent.
The transmission axis of the polarizer and the slow axis of the polymer substrate (PK-1) were arranged in parallel. The transmission axis of the polarizer and the slow axis of the triacetyl cellulose film were arranged so as to be orthogonal to each other. In this way, polarizing plates (HB1 to HB7) were produced.
When the polarizing plate was arranged in a crossed Nicol arrangement and 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.

[Comparative Example 1]
To the optically anisotropic layer, a fluoroaliphatic group-containing copolymer (Megafac F780 (manufactured by Dainippon Ink Co., Ltd.) with a molecular weight splitting condition changed as described below) was added, and Example 1 and Similarly, optical compensation sheets (KH-H1 to KH-H4) and further polarizing plates with KH-H1 (HB-H1 to HB-H4) were produced.
The conditions for molecular weight splitting are as follows. That is, Comparative Sample 1 has a molecular weight ratio of 10,000 or more of 4.2%, 20,000 or less ratio of 65.8%, and Comparative Sample 2 has a molecular weight of 10,000 or more ratio of 4.0% or 20,000 or less. 64.3%, comparative sample 3 has a molecular weight of 10,000 or more 3.9%, 20,000 or less has a ratio of 63.5%, and sample 4 has a molecular weight of 10,000 or more of 3.7. %, The ratio of 20,000 or less is 64.0%.

(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 (HB1) prepared in Example 1 were attached so as to sandwich the prepared bend alignment cell. The optically anisotropic layer of the elliptically polarizing plate faces the cell substrate, and the rubbing direction of the liquid crystal cell and the rubbing direction of the optically anisotropic layer facing the liquid crystal cell are arranged to be 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-Contrast160D, manufactured by ELDIM) as the contrast ratio of the transmittance ratio (white display / black display), the viewing angle can be adjusted in eight steps from black display (L1) to white display (L8). It was measured.
Moreover, the polarizing plate (HB-H1) produced by the comparative example 1 was 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 viewing angle of the liquid crystal cell using the polarizing plate (HB1) was sufficiently wide and uniform and satisfactory.

(Evaluation of unevenness on LCD panel)
The display panel of the liquid crystal display device of Example 1HB1) and Comparative Example 1 was adjusted to the whole halftone, and the unevenness was evaluated. In Example 1, 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.

(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 (HB1) produced in Example 2 is used instead as an optical compensation sheet. A single sheet was affixed to the observer side and the backlight side via an adhesive so that (KH1) was on the liquid crystal cell side.
The transmission axis of the polarizing plate on the viewer side and the transmission axis of the polarizing plate on the backlight side were arranged 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-Contrast160D, ELDIM company make). Wide and uniform viewing angle.

(Evaluation of unevenness on LCD panel)
The display panel of the liquid crystal display device of Example 2 was adjusted to the whole halftone, and unevenness was evaluated. No unevenness was observed from any direction.

[Evaluation of results]
Table 1 shows the evaluation results of drying unevenness and streaks of the optical films of Examples and Comparative Examples prepared as described above.
In Table 1, the sample for measuring the surface tension of the fluoropolymer MEK solution is a sample for measuring the surface tension by collecting 15 g of 100 g of a solution obtained by thoroughly mixing and homogenizing 0.137 g of the fluoropolymer and 99.863 g of MEK. A sample was used.
The surface evaluation shows the result of observing the polarizing plate on the optical compensation sheet (the optical compensation sheet KH1 of Example 1 in the same publication) prepared by the same method as that of JP-A-2004-198511. The evaluation criteria (evaluation levels are shown in Table 1.
Moreover, all were performed by the same method in the comparative example and the Example.
Table 1

  As shown in Table 1, all the examples of the present invention have good drying unevenness and streaks and have achieved the object of the invention.

Claims (10)

 In an optical film having an optically anisotropic layer containing a fluoropolymer and a liquid crystal compound on a support, the surface tension of the 0.137% by mass MEK solution of the fluoropolymer contained in the optically anisotropic layer is 21.0. [mN / m] or more and 22.0 [mN / m] or less.   The optical film according to claim 1, wherein the fluorine-containing polymer is a copolymer.   The optical film according to claim 1, wherein the fluorine-containing polymer has a hydrophilic monomer as a constituent monomer component.   The optical film according to claim 1, wherein the optical film has an alignment film on a support and an optically anisotropic layer is applied on the alignment film. In an optical film having an optically anisotropic layer containing a fluoropolymer and a liquid crystal compound on a support, the optically anisotropic layer is a repeating unit derived from the monomer (i) below and a monomer (ii) below The optical film according to claim 1, comprising a fluoroaliphatic group-containing copolymer containing a repeating unit derived from
(I) Fluoroaliphatic group-containing monomer represented by the following general formula [1] (ii) Poly (oxyalkylene) acrylate and / or poly (oxyalkylene) methacrylate General formula [1]

(In the general formula [1], R ₁ represents a hydrogen atom or a methyl group, X represents an oxygen atom, a sulfur atom or —N (R ₂ ) —, m is an integer of 1-6, and n is 2-4. R ₂ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.) An optical film having an optically anisotropic layer containing a fluoropolymer and a liquid crystal compound on a support, wherein the optically anisotropic layer is a repeating unit derived from the monomer (i) below, and the monomer (ii) below The optical film according to claim 5, comprising a fluoroaliphatic group-containing copolymer containing a repeating unit derived from the above and a repeating unit derived from the monomer (iii) below.
(I) the fluoroaliphatic group-containing monomer represented by the general formula [1] according to claim 5 (ii) poly (oxyalkylene) acrylate and / or poly (oxyalkylene) methacrylate (iii) (i) and Monomer represented by the following general formula [2] copolymerizable with (ii) [2]

(In the general formula [2], R ₃ represents a hydrogen atom or a methyl group, Y represents a divalent linking group, R ₄ represents a straight chain having 4 to 20 carbon atoms which may have a substituent, Represents a branched or cyclic alkyl group.)   The optical film according to claim 1, wherein the liquid crystal compound is a discotic compound.   An optical film according to any one of claims 1 to 7, wherein an optically anisotropic layer containing a fluorine-containing polymer and a liquid crystal compound is coated on an alignment film on a support. Production method.   A polarizing plate comprising the optical film according to claim 1.   A liquid crystal display device comprising the optical film according to claim 1.