KR20130096249A - Copolymerizable (meth)acrylic acid polymer, optical alignment film and phase difference film - Google Patents

Abstract

A copolymerizable (meth) acrylic acid polymer having excellent characteristics such as being soluble in a solvent having low toxicity and environmental load, a composition for a photoalignment film comprising the same, and a photoalignment film having a liquid crystal alignment ability in a film composed of the composition. And a phase difference film in which a liquid crystalline compound is oriented on the optical alignment film.
The copolymerizable (meth) acrylic acid polymer has a repeating unit represented by General Formula (I) (each symbol is as defined in the specification.).

Description

Copolymerizable (meth) acrylic acid polymer, optical alignment film and phase difference film}

The present invention relates to a copolymerizable (meth) acrylic acid polymer, an optical alignment film and a retardation film, and more particularly, a copolymerizable (meth) acrylic acid polymer having a side chain having a carboxyl group at the terminal and a side chain having an acrylic ester moiety at the terminal. The present invention relates to a photoalignment film composition comprising the same, a photoalignment film in which a liquid crystal alignment ability is generated in a film made of the composition, and a phase difference film in which a liquid crystal compound is aligned on the photoalignment film.

Background Art In recent years, in the field of displays (including liquid crystal displays and flexible displays), retardation films (optical anisotropic films) have been used in various forms. Such a retardation film is produced by applying a liquid crystalline compound on a film (or substrate) having a liquid crystal alignment capability, but conventionally, as a method for imparting liquid crystal alignment capability to the film (or substrate), the surface is chemically or physically treated. How to do is known. As such a method, the rubbing process which rubs a polymer resin film, such as a polyimide on the surface of a board | substrate, for example in textiles in one direction is known, and is used for formation of the alignment film for liquid crystal display devices, etc. However, in such a method, contamination of the liquid crystal manufacturing line due to the generation of fine dust, destruction of the TFT (thin film transistor) element by static electricity, or the like causes a decrease in the product ratio in the manufacturing process of the liquid crystal panel. There existed problems, such as difficulty in quantitative orientation control.

Therefore, in place of the rubbing process, various photo-alignment films which provide liquid crystal alignment capability by light irradiation have been proposed (Patent Documents 1 to 3). In particular, Patent Document 2 describes an optical alignment material obtained by polymerizing a monomer having a carboxyl group at a photoreactive side chain terminal as showing good photoreaction efficiency. However, such a photo-alignment material has a problem that it is difficult to suppress the manufacturing cost because the monomer which is a raw material is expensive. In addition, Patent Document 3 describes a copolymerizable polymer which solves the above problem by converting a part of the monomer to another cheaper monomer. Such other monomers have a common point of having a carboxyl group at the terminal, but do not include a structure exhibiting photoreactivity.

Generally, in order to manufacture a phase difference film using such a polymer, a polymer is first dissolved in a solvent, such a solution is applied onto a substrate, dried, and irradiated with linear polarization or the like, and heated as necessary to form a photoalignment film. It is done. Then, a liquid crystal compound is coated on the photoalignment film, heated to orient the liquid crystal compound, cured again, and then heated to improve the orientation to obtain a phase difference film. In such a process, as the solvent which dissolves the polymer for the first time, it is preferable that the toxicity or environmental load is as low as possible. However, the polymers described in Patent Documents 2 and 3 have poor solubility and use a relatively high solvent with toxicity and environmental load. There was a problem that can not be done.

In addition, the exposure amount at the time of irradiating linearly polarized light on the polymer coated on the substrate has an optimal range (optimal polarization exposure amount. In the present specification, also referred to simply as an optimal exposure amount) in manufacturing an optical alignment film. Since a limit value (limit polarization exposure amount, also referred to as limit exposure amount in the present specification) exists that the film deteriorates when the exposure amount is exceeded, it is necessary to reliably adjust the exposure amount in order to manufacture a highly suitable optical alignment film. Such adjustment is performed by adjusting the exposure intensity and exposure time by a machine for irradiating polarized light, but such an adjustment is made if the value of the optimum exposure dose is small (high photosensitivity) and the difference with the limit exposure dose is small. There was a problem that it became very difficult to carry out.

In addition, when manufacturing a phase difference film by orienting a liquid crystalline compound to a photo-alignment film, after heat-curing a liquid crystalline compound, it is necessary to heat to high temperature exceeding 200 degreeC, but the birefringence rate of a film before and after such a heating process. There was a problem that this decrease (low heat resistance).

(Patent Document 1) JPH08-015681 Publication (Patent Document 2) JP2007-304215 (Patent Document 3) JP2008-276149

In the above background, the present invention is a copolymerizable (meth) acrylic acid polymer, which can be dissolved in a solvent having low toxicity and environmental load, the composition for the photo-alignment film comprising the same, the liquid crystal alignment ability generated in the film composed of the composition An object of the present invention is to provide a photoalignment film and a phase difference film in which a liquid crystal compound is oriented on the photoalignment film.

The present invention also provides a copolymerizable (meth) acrylic acid polymer capable of suppressing a decrease in birefringence (high heat resistance) in a film forming process of a liquid crystal film, that is, a film heating (firing) process, and a composition for an optical alignment film comprising the same. It is an object of the present invention to provide a photoalignment film in which a liquid crystal alignment capability is generated in a film made of the composition, and a retardation film in which a liquid crystal compound is aligned on the photoalignment film.

In addition, the present invention has a relatively large value (low light sensitivity) of the polarized light to be irradiated when producing the optical alignment film, and / or a large difference between the optimal exposure amount and the threshold exposure amount, and easy adjustment of the exposure amount. It is an object to provide a copolymerizable (meth) acrylic acid polymer, a composition for a photoalignment film comprising the same, a photoalignment film having a liquid crystal alignment ability in a film composed of the composition, and a retardation film in which a liquid crystal compound is aligned on the photoalignment film. It is done.

As a result of earnestly researching the present inventors, when using the novel copolymerizable (meth) acrylic acid polymer which has the side chain which has a side chain which has a carboxyl group at the terminal, and the side chain which has an aryl acrylic acid ester (preferably cinnamon acid ester) part at the terminal, The present invention was completed by finding that the problem can be solved.

That is, the present invention,

〔One〕

The compound of formula (I)

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, and ring A and ring B are each independently,

[However, each of X ^{1 to} X ³⁸ is independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group.]

Z is a group represented by -CH = CHCOO- (trans) or -N = N-, p and q are each independently an integer of 1-12, m and n are , Mole fraction of each monomer in a copolymer satisfying the relationship of 0.65 ≦ m ≦ 0.95, 0.05 ≦ n ≦ 0.35, and m + n = 1.]

Copolymerizable (meth) acrylic acid polymer having a repeating unit represented by

[2] In addition, another embodiment of the present invention is a general formula (I-A)

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, each of X ^{1A to} X ^4A is each independently, A hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group, and ring B is

[However, X ^{1B to} X ^4B And X ^{31B to} X ^38B are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group.]

Z is a group represented by -CH = CHCOO- (trans) or -N = N-, p and q are each independently an integer of 1-12, m and n are It is the mole fraction of each monomer in the copolymer which satisfies the relationship of 0.65≤m≤0.95, 0.05≤n≤0.35 and m + n = 1.]

Copolymerizable (meth) acrylic acid polymer having a repeating unit represented by

[3] The present invention also provides general formula (I-a)

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, each of X ^{1A to} X ^4A is each independently hydrogen An atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group, and ring B is

[However, each of X ^{1B to} X ^4B and X ^{31B to} X ^38B is each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group.]

P and q are each independently an integer of any one of 1 to 12, and m and n are copolymers satisfying a relationship of 0.65 ≦ m ≦ 0.95, 0.05 ≦ n ≦ 0.35, and m + n = 1 Mole fraction of each monomer in

Copolymerizable (meth) acrylic acid polymer having a repeating unit represented by

[4] The present invention also provides general formula (I-b)

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, X ^{1A to} X ^4A And each of X 3 ^{1B to} X ^38B is each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group, p and q are each independently an integer of any one of 1 to 12, and m and n are , Mole fraction of each monomer in a copolymer satisfying the relationship of 0.65 ≦ m ≦ 0.95, 0.05 ≦ n ≦ 0.35, and m + n = 1.]

Copolymerizable (meth) acrylic acid polymer having a repeating unit represented by

[5] The present invention also provides general formula (I-c)

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, X ^{1A to} X ^4A And each of X ^{1B to} X ^4B is, independently, a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group, and Z is a group represented by -CH = CHCOO- (trans) or -N = N-, p and q are each independently an integer of any one of 1-12, and m and n are the mole fractions of each monomer which occupies the copolymer which satisfy | fills the relationship of 0.65 <= m <0.95, 0.05 <= n <0.35, and m + n = 1 Copolymerizable (meth) acrylic acid polymer having a repeating unit represented by

[6] a composition for a photo-alignment film, comprising the copolymerizable (meth) acrylic acid polymer according to any one of the above [1] to [5];

[7] An optical alignment film in which light having anisotropy is irradiated to the film made of the composition for optical alignment films of [6], and then heated to generate liquid crystal alignment ability;

[8] The present invention relates to a retardation film in which a liquid crystal compound is oriented on the photoalignment film of [7].

The copolymerizable (meth) acrylic acid polymer (I) of the present invention is excellent in being soluble in methyl ethyl ketone and / or cyclohexanone and / or 1-methoxy-2-propanol which are solvents having low toxicity and low environmental load. Has Moreover, since methyl ethyl ketone, cyclohexanone, and 1-methoxy- 2-propanol have a low boiling point of about 80 degreeC, about 155 degreeC, and about 120 degreeC, respectively, the drying process for removing a solvent becomes easy by that much. Has an advantage.

In addition, if the polymer of the present invention uses this as an alignment film and aligns the liquid crystalline compound again to produce a retardation film, the decrease in the birefringence of the film in the heating step in the film forming process of the retardation film can be suppressed (that is, The heat resistance of the film is increased), and / or the value of the optimal exposure amount of polarized light to be irradiated when producing the optical alignment film becomes relatively large and / or the difference between the optimum exposure amount and the limit exposure amount becomes large (that is, the adjustment of the exposure amount becomes easy). It has an outstanding characteristic.

In the polymer (1) of this invention, a preferable specific example is shown below.

General formula (I-A)

[Symbols in the formula have the same meaning as above.]

A copolymerizable (meth) acrylic acid polymer having a repeating unit represented by

General formula (I-B)

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, and ring A and ring B are each independently

[Each of X ^{1 to} X ³⁸ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group.]

P and q are each independently an integer of any one of 1 to 12, and m and n are copolymers satisfying a relationship of 0.65 ≦ m ≦ 0.95, 0.05 ≦ n ≦ 0.35, and m + n = 1 Mole fraction of each monomer in

A copolymerizable (meth) acrylic acid polymer having a repeating unit represented by

General formula (I-a)

[In formula, a symbol has the same meaning as the above.]

A copolymerizable (meth) acrylic acid polymer having a repeating unit represented by

General formula (I-b)

[In formula, a symbol has the same meaning as the above.]

A copolymerizable (meth) acrylic acid polymer having a repeating unit represented by

General formula (I-c)

[In formula, a symbol has the same meaning as the above.]

In General Formula (I) of the present invention (including General Formulas (IA) and (IB) and General Formulas (Ia) to (Ic). The same applies hereinafter), R ¹ is preferably a methyl group. As R ² , an alkyl group or a phenyl group substituted with an alkyl group, an alkoxy group, a cyano group, and a group selected from a halogen atom is preferable, and among these, a phenyl group substituted with an alkyl group or a cyano group is more preferable, and an alkyl group is most preferred. Do. As another preferable example of R <^2> , the alkyl group or the phenyl group substituted by the alkoxy group or the cyano group is mentioned, Among these, the phenyl group substituted by the alkyl group or the alkoxy group is preferable. As another preferable example of R <^2> , the phenyl group substituted by the alkoxy group or the cyano group is mentioned, Among these, the phenyl group substituted by the alkoxy group is more preferable. Another preferable example of R ² is an alkyl group. As X ^{1 to} X ³⁸ , all hydrogen atoms or halogen atoms are preferable. As p and q, the integer in any one of 3-9 is preferable in all, Among these, the integer in any one of 5-7 is preferable, and 6 is the most preferable. For m, it is preferably in the range of about 0.75 ≦ m ≦ about 0.85, most preferably about 0.8. The preferable range of corresponding n is a range determined by itself from m + n = 1. That is, preferably in the range of about 0.15 ≦ n ≦ about 0.25, most preferred is about 0.2.

In general formula (I) of this invention, as X <^1A> -X <^4A> , a hydrogen atom or a halogen atom is preferable, In particular, it is preferable that any one of X <^1A> -X <^4A> is a halogen atom, and others are hydrogen atoms, Moreover, the case where all are hydrogen atoms is the most preferable. Moreover, as X <^31B> -X <^38B> , a hydrogen atom or a halogen atom is preferable and the case where all are hydrogen atoms is the most preferable.

The alkyl group of the substituent of the phenyl group of the alkyl group of R ² or R ^2, there can be mentioned an alkyl group having 1 to 12 carbon atoms having 1 to 6 carbon atoms is preferably from that, it is more preferably from 1 to 4 carbon atoms, and most preferably For example, a methyl group is mentioned. As an alkoxy group of the substituent of the phenyl group of R <^2> , a C1-C12 alkoxy group is mentioned, Preferably, a C1-C6 thing, More preferably, a C1-C4 thing, Most preferably, methoxy The season can be mentioned. As a halogen atom of the substituent of the phenyl group of R <^2> , a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, Among these, a fluorine atom is preferable. Examples of the alkyl group in X ^{1 to} X ³⁸ include those having 1 to 4 carbon atoms, of which methyl group is most preferred, and examples of the alkoxy group include those having 1 to 4 carbon atoms, of which methoxy group is most preferred. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, Among these, a fluorine atom is preferable.

In addition, with respect to the specification in the X ^1A ~X ^38A, the ring A or a substituent of X ¹ ~X ³⁸ on the ring B, shows a case in which they substituents on the ring A, X ^1B ~X ^38B is, they are a substituent on the ring B It indicates the case. Therefore, the description about X ^{1 to} X ³⁸ is also applicable to X ^1A to X ^{3 8A} and X ^{1B to} X ^38B as it is.

Polymer (I) of the present invention is a general formula (II),

[In formula, a symbol has the same meaning as the above.]

A predetermined amount of the (meth) acrylic acid monomer (M1) and the general formula (III),

[In formula, a symbol has the same meaning as the above.]

It can manufacture by mixing the predetermined amount of the (meth) acrylic-acid monomer (M2) represented by in a solventless or solvent, and polymerizing. The polymerization can be carried out using light or heat. In the polymerization step, a method of adding a material, a solvent, or the like is not particularly limited, and polymerization may be initiated after all materials have been added to the reaction vessel before polymerization, and after mixing M1 and M2, such a mixture or solvent may be used. After the polymerization is started for a part, the remainder may be added stepwise by a method such as dropwise addition or split addition.

Moreover, although it is not essential at the time of the superposition | polymerization of M1 and M2, you may contain another monomer, and such a monomer is not specifically limited in another point, as long as it is a compound which has a polymerizable ethylenically unsaturated bond, A liquid crystal You do not have to have a last name.

As such a monomer, for example, methyl (meth) acrylate, t-butyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, ethoxyethyl (meth) acrylate, (Meth) acrylic monomers such as hydroxyethyl (meth) acrylate, phenyl (meth) acrylate, N, N-dimethylacrylamide, styrene, α-methylstyrene, p-styrenesulfonic acid, ethyl vinyl ether, N- Vinyl monomers such as vinylimidazole, vinyl acetate, vinylpyridine, 2-vinyl naphthalene, vinyl chloride, vinyl fluoride, N-vinylcarbazole, vinylamine, vinylphenol, and N-vinyl-2-pyrrolidone, 4 Aryl type monomers, such as -aryl-1, 2-dimethoxybenzene, 4-arylphenol, and 4-methoxyarylbenzene, maleimide, such as phenyl maleimide and cyclohexyl maleimide, are mentioned.

When superposing | polymerizing in a solution, the general purpose organic solvent can be used without a restriction | limiting in particular. Specific examples of the solvent include alcohol solvents such as ethanol, propanol and butanol, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and cyclopentanone, ethyl acetate, butyl acetate and propylene glycol mono Ester solvents such as methyl ether acetate, ether solvents such as diethyl ether and diglyme, hydrocarbon solvents such as hexane, cyclohexane, methylcyclohexane, toluene and xylene, and nitrile solvents such as acetonitrile And amide solvents such as N-methyl pyrrolidone and dimethylacetamide. These solvents may be used alone or in combination of two or more thereof.

In the case of the said superposition | polymerization, a polymerization initiator can be used. The polymerization initiator may be generally used, and specific examples thereof include azobis isobutyronitrile (AIBN), diethyl-2,2'-azobisisobutyrate (V-601), and 2,2'-azobis. Azo polymerization initiators such as (2,4-dimethylvaleronitrile), dimethylazobismethylpropionate, peroxide polymerization initiators such as benzoyl peroxide, hydrogen peroxide, and lauroyl peroxide, potassium persulfate, ammonium persulfate, and the like. Persulfate type polymerization initiator etc. are mentioned. Any one of these polymerization initiators may be used alone, or two or more kinds may be used in combination.

Although the temperature at the time of the said superposition | polymerization changes with kinds of monomers M1 and M2, polymerization solvent species, initiator species, etc., Preferably it is 40-150 degreeC, More preferably, it is the range of 50-120 degreeC.

The polymer (1) of the present invention thus obtained can be appropriately added to a polymerizable composition that generates polymerization by light and heat, in addition to a photopolymerization initiator, a surfactant, a solvent, and the like, to form a composition for a photoalignment film. have. Although content of these arbitrary components is not specifically limited, Usually, with respect to the total weight of a polymer (I), about 1 to about 10 weight% of photoinitiators, about 0.1 to about 5 weight% of surfactant, and about 70 to about solvent It is preferable that 99 weight% is included.

As a photoinitiator, all the general-purpose photoinitiators generally known can be used in order to form a uniform film | membrane by a small amount of light irradiation. As a specific example, Azonitrile type photoinitiators, such as 2,2'- azobisisobutyronitrile and 2,2'- azobis (2, 4- dimethylvaleronitrile), Irgacua 907 (Chiba, for example) Α-amino ketone photopolymerization initiators such as Specialty Chemicals Co., Ltd.) and Irgacua 369 (Ciba Specialty Chemicals Co., Ltd.), 4-phenoxydichloroacetphenone, 4-t-butyldichloroacetphenone, diethoxy Acetphenone, 1- (4-isopropyl phenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2-benzyl-2-dimethylamino-1- (4- Acetphenone photoinitiators, such as morpholinophenyl) -butan-1-one, Benzoin type photoinitiators, such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzyl dimethyl ketal, and benzophenone , Benzoyl benzoic acid, methyl benzoyl benzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylate ben Benzophenone-type photoinitiators, such as a phenone and 4-benzoyl-4'-methyldiphenyl sulfide, 2-chlor chioxane, 2-methyl thioxanthone, an isopropyl thioxone, and 2, 4- diisopropyl level Chioxanson type photoinitiators, such as an oxone, 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p-meth Methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2-pipero Nyl-4,6-bis (trichloromethyl) -s-triazine, 2,4-bis (trichloromethyl) -6-styryl s-triazine, 2- (naphtho-1-yl) -4 , 6-bis (trichloromethyl) -s-triazine, 2- (4-methoxynaphtho-1-yl) -4,6-bis (trichloromethyl) -s-triazine, 2,4- Triazine photoinitiators such as trichloromethyl- (piperonyl) -6-triazine, 2,4-trichloromethyl (4′-methoxystyryl) -6-triazine, carbazole photopolymerization initiators, Dazole-based light weight A polymerization initiator, etc. Further, α-acyloxy ester, acylphosphine oxide, methylphenylglyoxylate, benzyl, 9, 10-phenan srenquinone, camphor-quinone, ethyl anthraquinone, 4,4'-diethyl isopropyl And photopolymerization initiators such as tarophenone, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, 4,4'-diethylaminobenzophenone and thioxanthone. A photoinitiator may be used independently and may use 2 or more types together.

As surfactant, in order to form a uniform film | membrane, all the surfactant generally used can be used. As a specific example, for example, sodium lauryl sulfate, lauryl ammonium sulfate, lauryl triethanolamine, polyoxyethylene alkyl ether sulfate, alkyl ether phosphate, sodium oleyl succinate, potassium myristic acid potassium, palm oil fatty acid potassium, sodium Anionic surfactants such as lauroyl salcosinate; nonionic surfactants such as polyethylene glycol monolaurate, sorbitan stearate, glyceryl myristin, glyceryl diorate, sorbitan sterate, and sorbitan oleate Chaotytic surfactants such as stearyl trimethylammonium chloride, behenyltrimethylammonium chloride, stearyldimethylbenzylammonium chloride, cetyltrimethylammonium chloride; laurylbetaine, alkylsulfobetaine, cocamidepropylbetaine, alkyldimethyl Alkylbetaines, such as amino acid betaine, alkyl imidazolines, lauroyl sarcosine Amphoteric surfactants such as sodium and sodium cocoan acetate; moreover, BYK-361, BYK-306, BYK-307 (manufactured by BIC Chem Japan), Floroid FC430 (manufactured by Sumitomo 3M), mega perc F171, R08 (die Surfactants, such as the Nippon Ink Chemical Industries, Ltd. make), etc. are mentioned. These surfactant may be used independently and may use 2 or more types together.

As the solvent, toluene, ethylbenzene, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, propylene glycol methyl ether, dibutyl ether, acetone, methyl ethyl ketone, ethanol, propanol, cyclohexane, cyclopentanone, methylcyclohexane, tetra Hydrofran, dioxane, cyclohexanone, n-hexane, ethyl acetate, butyl acetate, propylene glycol methyl ether acetate, methoxybutyl acetate, N-methylpyrrolidone, dimethylacetamide, and the like. Methyl ethyl ketone and cyclohexanone are preferable from the viewpoint of toxicity and environmental load and / or solvent resistance to resin substrates (for example, polyethylene terephthalate (PET), cycloolefin polymer (COP), etc.). These may use any one independently and may use 2 or more types together. In particular, the polymer (I) of this invention has the outstanding characteristic of melt | dissolving also in methyl ethyl ketone, cyclohexanone, and 1-methoxy- 2-propanol.

The composition for the photo-alignment film of the present invention thus obtained is applied to a substrate to remove the solvent to form a film, and then the film is irradiated with light having anisotropy, and heated again to cause liquid crystal alignment ability. It can be set as an alignment film.

As a coating method of the composition for photo-alignment films, any method generally known in the said field may be sufficient, For example, a spin coating method, the bar coating method, the dikota method, the screen printing method, the spray coater method, etc. are mentioned. After application of the composition, a layer of the composition is formed by drying to remove the solvent. The drying step may be any method commonly used in this field until the resin layer is immobilized in a constant form to form a film.

As a base material which can be used, For example, glass base materials, such as alkali glass and an alkali free glass, polyimide, polyamide, acrylic resin, polyvinyl alcohol, triacetyl cellulose, polyethylene terephthalate, a cycloolefin polymer, polyethylene, a polycarbonate And resin substrates such as polystyrene and polytrifluoroethylene, and metal substrates such as iron, aluminum, and copper, and the like, and glass substrates are more preferable.

As light which has anisotropy, partial polarization etc. are mentioned other than linearly polarized light, for example. Here, linearly polarized light is light in which the surface containing the vibration direction of an electric field (or magnetic field) is specified in one, and partial polarization means that the intensity | strength of the vibration of an electric field (or magnetic field) is stronger than the other direction with respect to a specific direction. Linearly polarized light can be solidified by using a polarizing filter or a polarizing prism for light from a light source. Partial polarization is obtained using a partial polarization filter. In the present invention, any light can be used as long as it has anisotropy. In order to efficiently perform photoalignment, it is preferable to use linearly polarized light. The irradiated light is not particularly limited as long as it is irradiated radiation that generates a chemical reaction by irradiation, such as infrared rays, visible rays, ultraviolet rays (near ultraviolet rays, far ultraviolet rays, etc.), X-rays, charged particle beams (e.g., electron lamps), and the like. In general, however, the irradiation rays often have a wavelength of 200 nm to 500 nm, and near ultraviolet rays of 350 nm to 450 nm are preferable in terms of effectively generating optical crosslinking. As a light source, a xenon lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a metal halide lamp, etc. are mentioned, for example. Purple external light or visible light obtained by such a light source may limit the wavelength range irradiated using an interference filter, a color filter, or the like. Although irradiation energy (optimal exposure amount) changes with kinds of polymer (I), it is usually about 5 mJ / cm <2> -50mJ / cm <2>.

Moreover, when irradiating polarized light, when a photomask is used, two or more liquid crystal aligning ability can be made to arise in a pattern form in a direction different from a photo-alignment film. Specifically, after applying and drying the composition for the photo-alignment film of the present invention, a photomask is put thereon and irradiated with light having anisotropy to give only the exposed portion liquid crystal alignment ability, and if necessary, change the direction, By repeating, the liquid crystal alignment ability can be generated in a pattern form in a plurality of directions.

When the heating is performed after the light irradiation, heat polymerization proceeds, and thus a photo-alignment film having a higher durability with respect to light, heat and the like can be obtained. The heating temperature is not particularly limited as long as the polymerization is sufficient to proceed. Generally, the heating temperature is about 80 to 250 ° C, preferably about 100 to 200 ° C, and more preferably about 120 to 170 ° C. When heat-polymerizing, you may add the polymerization initiator generally used in a composition, and do not need to add it. It is preferable that the film thickness of the photo-alignment film formed by the above is about 10 to about 500 nm, More preferably, the range of about 100 to about 500 nm, about 100 to about 200 nm is more preferable.

A phase difference film is formed by apply | coating a liquid crystalline compound on the photo-alignment film obtained above, heating, irradiating UV-light, and heating-firing again.

As a liquid crystalline compound, the polyfunctional liquid crystalline (meth) acrylate which has a polymeric group in a molecule | numerator, a liquid crystalline epoxy compound, and a liquid crystalline oxetane compound are mentioned. Among these, polyfunctional liquid crystalline (meth) acrylate is preferable.

As a polyfunctional liquid crystalline (meth) acrylate, the compound etc. which are represented by following formula (IV)-(VI) are mentioned, for example.

(IV)

[In formula, n is an integer of 1-18, R is a hydrogen atom or a methyl group.]

(Expression V)

[In formula, n is an integer of 1-18, R is a hydrogen atom or a methyl group, Z is a hydrogen atom, a halogen atom, or a C1-C8 alkyl group.]

(Expression VI)

[In formula, n is an integer of 1-18, R is a hydrogen atom or a methyl group, Z is a hydrogen atom, a halogen atom, or a C1-C8 alkyl group.]

As a liquid crystalline epoxy compound, the compound etc. which are represented by following formula (VII) are mentioned, for example.

(VII)

(In formula, n represents the integer of 1-20, m represents the integer of 2-15.)

As a liquid crystalline oxetane compound, the compound etc. which are represented by following formula (VIII) are mentioned, for example.

(Formula VIII)

[In formula, n is an integer of 1-18, Z is a hydrogen atom, a halogen atom, or a C1-C8 alkyl group.]

As a temperature at the time of heating after apply | coating a liquid crystalline compound, it is about 50-100 degreeC normally, about 60-90 degreeC is preferable, and it is more preferable that it is about 65-85 degreeC.

Irradiation of UV light can be performed similarly to irradiation with said photo-alignment film. Heat baking can also be performed by a conventional method, and the temperature is about 150-300 degreeC normally, about 200-250 degreeC is preferable, and it is more preferable that it is about 210-230 degreeC. The heating firing time is about 0.5 to 3 hours, preferably about 0.6 to 2 hours, and most preferably about 0.6 to 1.5 hours.

As for the retardation film of this invention obtained in this way, although the film thickness changes with a use etc., generally, the range of 0.1-20.0 micrometers is preferable, and the range of 1.0-5.0 micrometers is more preferable.

General formula (I) of this specification shows typically that M1 and M2 which are raw material monomers are contained by the molar ratio of m: n, and M1 and M2 do not necessarily couple | bond alternately and comprise the copolymer. . Therefore, general formula (1) contains the copolymer which superposed | polymerized M1 and M2 in the molar ratio of m: n, for example, any of alternating type, random type, and graft type. Moreover, in general formula (I), the broken line which connects monomers is a single bond loss normally, but when it contains another monomer at the time of superposition | polymerization of M1 and M2, these monomers may exist in the said broken line part, and may exist. have.

Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to the following Example originally.

1.Synthesis of Copolymer (Meta) acrylic Acid Polymer

[Example 1]

Poly [1- [6- [4- [4-[(E) -2-methoxycarbonylvinyl] phenoxycarbonyl] phenoxy] hexyloxycarbonyl] -1-methylethylene-CO-1- [6- [4-carboxyphenoxy] hexyloxycarbonyl] -1-methylethylene] (M1: M2 = 90: 10) (polymer 1)

4-g (11 mmol) 4- [6- (2-methylacryloyloxy) hexyloxy] benzoic acid 4-[(E) -2-methoxycarbonylvinyl] phenyl ester, 4- [6- (2- 29.6 g (96 mmol) of methylacryloyloxy) hexyloxy] benzoic acid and 0.35 g (2.1 mmol) of 2,2'-azobisisobutyronitrile were dissolved in 196 g of cyclohexanone. Nitrogen was passed through this solution for 1 hour. Then heated at 80 ° C. After 10 hours, the reaction solution was cooled and added dropwise to 346 g of normal hexane at room temperature with vigorous stirring. The separated polymer was filtered off and 26 g of Polymer 1 was obtained by drying at 50 ° C under reduced pressure.

<Measurement of Weight Average Molecular Weight (MW)>

The weight average molecular weight (MW) of the polymer obtained above was measured using gel filtration chromatography (GPC). The obtained weight average molecular weight (MW) was 30700.

<Measurement of acid value>

The measurement method is as follows. In other words, about 60 mL of THF was taken into a 100 mL triangular flask, and phenolphthalein was neutralized with an aqueous 0.1 mol / L sodium hydroxide solution as an indicator. About 1.5 g of a polymer was weighed, uniformly dissolved in the solution, stirred, and 0.1 mol The titration was performed by titration with an aqueous solution of / L sodium hydroxide, and the point that the off-red color did not disappear for about 30 seconds.

The acid value was calculated according to the following equation.

Acid value = (0.1 × f × A × 56.1 / B) / (C / 100)

A ： appropriate amount (ml)

f ： titer of sodium hydroxide aqueous solution

B: Polymer composition amount (g) (amount of solution after titration completion including polymer)

C: Polymer concentration (%) (polymer amount / polymer composition amount * 100)

The acid value of the polymer obtained above was 156 mgKOH / g.

<Measurement of phase transition temperature>

It was 160-180 degreeC when the phase transition temperature of the polymer obtained above was measured using differential scanning calorimetry (DSC).

[Example 2]

Poly [1- [6- [4- [4-[(E) -2-methoxycarbonylvinyl] phenoxycarbonyl] phenoxy] hexyloxycarbonyl] -1-methylethylene-CO-1- [6- [4-carboxyphenoxy] hexyloxycarbonyl] -1-methylethylene] (M1: M2 = 80: 20) (polymer 2)

8 g (17 mmol) of 4- [6- (2-methylacryloyloxy) hexyloxy] benzoic acid 4-[(E) -2-methoxycarbonylvinyl] phenyl ester, 4- [6- ( 21 g (69 mmol) of 2-methylacryloyloxy) hexyloxy] benzoic acid, 0.28 g (1.7 mmol) of 2,2'-azobisisobutyronitrile, and 116 g of cyclohexanone Except to carry out, it processed like Example 1 and obtained 24g of polymers 2.

The obtained polymer had a weight average molecular weight (MW) 31700, acid value 130 mgKOH / g, and phase transition temperature of 148-173 degreeC.

[Example 3]

Poly [1- [6- [4- [4-[(E) -2-methoxycarbonylvinyl] phenoxycarbonyl] phenoxy] hexyloxycarbonyl] -1-methylethylene-CO-1- [6- [4-carbocarboxyphenoxy] hexyloxycarbonyl] -1-methylethylene] (M1: M2 = 70: 30) (polymer 3)

10 g (21 mmol) of 4- [6- (2-methylacryloyloxy) hexyloxy] benzoic acid 4-[(E) -2-methoxycarbonylvinyl] phenyl ester, 4- [6- 15.3 g (50 mmol) of (2-methylacryloyloxy) hexyloxy] benzoic acid, 0.23 g (1.4 mmol) of 2,2'-azobisisobutyronitrile, and cyclohexanone Except having used the amount of 101.2g and normal hexane as 253g, it processed similarly to Example 1 and obtained 24g of polymers 3.

The obtained polymer had a weight average molecular weight (MW) 33300, and the acid value had 110 mgKOH / g phase transition temperature of 155-166 degreeC.

[Example 4]

Poly [1- [6- [4- [4-[(E) -2-methoxycarbonylvinyl] phenoxycarbonyl] phenoxy] hexyloxyoxycarbonyl] -1-methylethylene-CO-1- [6- [3-Fluoro-4-carboxyphenoxy] hexyloxycarbonyl] -1-methylethylene] (M1: M2 = 81: 19) (polymer 4)

2 g (4 mmol) of 4- [6- (2-methylacryloyloxy) hexyloxy] benzoic acid 4-[(E) -2-methoxycarbonylvinyl] phenyl ester, 2-fluoro-4- [6 5.6 g (17 mmol) of (2-methylacryloyloxy) hexyloxy] benzoic acid, 0.11 g (0.6 mmol) of 2,2'-azobisisobutyronitrile, 116 g of cyclohexanone, and 76 g of normal hexane In the same manner as in Example 1, 5 g of a polymer 4 was obtained.

The obtained polymer had a weight average molecular weight (MW) 48200, the acid value of 132 mgKOH / g, and a phase transition temperature of 85-120 degreeC.

EXAMPLE 5

Poly [1- [6- [4-[(E) -2- [4-cyanophenoxy] carbonylvinyl] phenoxy] hexyloxycarbonyl] -1-methylethylene-CO-1- [6 [4-carboxyphenoxy] hexyloxycarbonyl] -1-methylethylene] (M1: M2 = 80: 20) (polymer 5)

4- [6- (2-methylacryloyloxy) hexyloxy]-(E) -cinnamic acid 4-cyanophenylester (23 mmol), 4- [6- (2-methylacryloyloxy) hex Example 1 except that 28 g (92 mmol) of siloxy] benzoic acid was used, except that 0.38 g (2.3 mmol) of the 2,2'-azobisisobutyronitrile was used and 153 g of the cyclohexanone was used. In the same manner, 22 g of Polymer 5 was obtained.

The obtained polymer had a weight average molecular weight (MW) 24800, the acid value 135 mgKOH / g, and the phase transition temperature 160-180 degreeC.

[Comparative Example 1]

Poly [1- [6- [4-[(E) -2-hydrokisicarbonylvinyl] phenoxy] hexyloxycarbonyl] -1-methylethylene] (polymer 6)

20 g (23 mmol) of 4- [6- (2-methylacryloyloxy) hexyloxy]-(E) -cinnamic acid were used, and the amount of 2,2'-azobisisobutyronitrile was 0.2 g ( 1.2 mmol) and the same process as in Example 1 were carried out except that 80 g of cyclohexanone was used, thereby obtaining 17 g of Polymer 6.

The obtained polymer had a weight average molecular weight (MW) 35000, the acid value 169 mgKOH / g, and the phase transition temperature 162-197 degreeC.

[Comparative Example 2]

Poly [1- [6- [4-[(E) -2-hydroxycarbonylvinyl] phenoxy] hexyloxycarbonyl] -1-methylethylene-CO-1- [6- [4-carboxyphenoxy Ci] hexyloxycarbonyl] -1-methylethylene] (polymer 7) 4- [6- (2-methylacryloyloxy) hexyloxy]-(E)-cinnamic acid 10 g (30 mmol), 4- 37 g (120 mmol) of [6- (2-methylacryloyloxy) hexyloxy] benzoic acid were used, and the usage-amount of 2,2'- azobisisobutyronitrile was 0.5 g (3.0 mmol) of cyclohexanone 40g of polymers 7 were obtained in the same manner as in Example 1 except that the amount of use was 187 g.

The obtained polymer had a weight average molecular weight (MW) 31000 and the acid value 178 mgKOH / g phase transition temperature of 155-182 degreeC.

[Example 6]

Poly [1- [6- [4-[(E) -2- [4-methoxyphenoxy] carbonylvinyl] phenoxy] hexyloxycarbonyl-1-methylethylene-CO-1- [6- [ 4-carboxyphenoxy] hexyloxycarbonyl] -1-methylethyl] (M1: M2 = 80: 20) (polymer 8)

10.0 g (23 mmol) of 4- [6- (2-methylacryloyloxy) hexyloxy]-(E) -cinnamic acid 4-methoxyphenyl ester, 4- [6- (2-methylacryloyloxy Example) Except that the usage-amount of 2,2'- azobisisobutyronitrile is 0.5g (3 mmol) and the usage-amount of cyclohexanone is 152g using 27.9g (91 mmol) of hexyloxy] benzoic acid The same treatment as in 1 was carried out to obtain 25 g of the polymer 8.

The obtained polymer had a weight average molecular weight (MW) 46000, an acid value 135 mgKOH / g, and a phase transition temperature of 70-146 degreeC.

[Example 7]

Poly [1- [6- [4- [4-methoxyphenylazo] phenoxy] hexyloxycarbonyl] -1-methylethylene-CO-1- [6- [4-carboxyphenoxy] hexyloxyca Levonyl] -1-methylethylene] (M1: M2 = 80: 20) (polymer 9) 1- (4-methoxyphenylazo) -4- [6- (2-methyl acryloyloxy) hexyl oxy] The use amount of 2,2'- azobisisobutyronitrile using 10.0 g (25 mmol) of benzene, 30.9 g (100 mmol) of 4- [6- (2-methylacryloyloxy) hexyloxy] benzoic acid 33g of polymers 9 were obtained in the same manner as in Example 1 except that 0.4 g (3 mmol) and the amount of cyclohexanone used were 123 g.

The obtained polymer had a weight average molecular weight (MW) of 48000, an acid value of 138 mgKOH / g, and a phase transition temperature of 72 to 148 ° C.

2. Preparation of composition for photoalignment film

Polymers 1-9 were dissolved in cyclohexanone at a concentration of 5% by weight, respectively, to obtain compositions 1-9 for the photoalignment film.

3. Preparation of Photoalignment Film

The composition 1 for photo-alignment film was apply | coated so that it might become thickness of about 100 nm using the spin coater on the glass substrate. Then, it dried at 80 degreeC and continuously irradiated 40mJ / cm <2> of linearly-polarized UV light. Subsequently, heat processing was performed at 150 degreeC for 10 minutes, and orientation was produced and the photo-alignment film 1 was produced.

Using the composition 2 for photo-alignment films, the photo-alignment film 2 was produced in the same manner as in the preparation of the photo-alignment film 1 except that the irradiation amount of the linearly polarized UV light was 30 mJ / cm 2, and the subsequent heat treatment temperature was 140 ° C.

Using the composition 3 for photo-alignment films, the photo-alignment film 3 was produced in the same manner as in the preparation of the photo-alignment film 1 except that the irradiation amount of the linearly polarized UV light was 20 mJ / cm 2 and the subsequent heat treatment temperature was 140 ° C.

Using the composition 4 for photo-alignment films, the photo-alignment film 4 was produced like the manufacture of the photo-alignment film 1 except that the irradiation amount of linearly polarized UV light was 30 mJ / cm 2, and the subsequent heat treatment temperature was 110 ° C.

Using the composition 5 for photo-alignment films, the photo-alignment film 5 was produced in the same manner as in the preparation of photo-alignment film 1 except that the irradiation amount of the linearly polarized UV light was 5 mJ / cm 2, and the subsequent heat treatment temperature was 140 ° C.

The composition 6 for photo-alignment film was apply | coated so that it might become thickness of about 100 nm using the spin coater on the glass substrate. Then, it dried at 120 degreeC and then irradiated with 5mJ / cm <2> of linearly-polarized UV light. Subsequently, heat processing was performed at 160 degreeC for 10 minutes, and orientation was produced and the photo-alignment film 6 was produced.

Using the composition 7 for photo-alignment films, the photo-alignment film 7 was produced like the manufacture of the photo-alignment film 6 except that the irradiation amount of linearly-polarized UV-rays was 15 mJ / cm <2>, and the heat processing temperature after that was 150 degreeC.

Using the composition 8 for photo-alignment films, the photo-alignment film 8 was produced in the same manner as in the preparation of the photo-alignment film 1 except that the irradiation amount of the linearly polarized UV light was 20 mJ / cm 2, and the subsequent heat treatment temperature was 130 ° C.

Using the composition 9 for photo-alignment films, the photo-alignment film 9 was produced in the same manner as in the preparation of the photo-alignment film 1 except that the irradiation amount of the linearly polarized UV light was 10 mJ / cm 2, and the subsequent heat treatment temperature was 130 ° C.

4. Preparation of Retardation Film

Bifunctional liquid crystalline acrylate represented by the following formula (VI-a)

The composition for phase difference films was prepared by 19 weight%, the photoinitiator (Igagaurea 907 Chiba Specialty Chemicals make) 1 weight%, and propylene glycol monomethyl ether acetate.

The prepared composition for phase difference film was apply | coated to the photo-alignment film image 1 so that it might become thickness of about 2 micrometers using a spin coater. Then, it orientated at 70 degreeC, and irradiated with 100 mJ / cm <2> of unpolarized UV light continuously. Subsequently, heat baking was performed at 230 degreeC for 1 hour, and the retardation film 1 was produced.

Thus, phase difference films 2-9 were produced on the photo-alignment films 2-9, respectively.

5. Performance Evaluation

<Solubility of Polymer>

The solubility with respect to the various solvents in 1, 5, 10, and 20% of the polymers 1-7 was visually evaluated, and the thing which melt | dissolved completely, (circle) and melt | dissolved what was left as (triangle | delta) and insoluble were recorded as x. A result is shown in Table 1 (where (circle), (DELTA), and X mean, it is the same in a following table).

The solubility in various solvents in 1, 5, 10, and 20% of the polymers 8 and 9 was visually evaluated. The results are shown in Table 2.

The solubility to 1-methoxy-2-propanol in 1, 5, 10, 20% of the polymers 1-9 was visually evaluated. The results are shown in Table 3.

<Photosensitive sensitivity of polymer (polarization exposure amount)>

Retardation film was produced on the produced photo-alignment film about the optimal polarization exposure amount and limit polarization exposure amount of the photo-alignment film produced using the polymer 1-7, and the evaluation was performed from the orientation. The polarization exposure amount with the highest orientation is made into the optimal polarization exposure amount, and the exposure amount which orientation property starts to fall is made into the limit polarization exposure amount, and a result is shown in Table 4. FIG.

Retardation film was produced on the produced photo-alignment film about the optimal polarization exposure amount and limit polarization exposure amount of the photo-alignment film produced using the polymers 8 and 9, and the orientation was evaluated. The results are shown in Table 5.

At the time of preparation of the retardation film on the photo-alignment film produced using the polymers 1-7, the retention rate of the birefringence rate before and after the baking process was evaluated. The measurement of the birefringence was performed using the polarization analyzer OPTIPRO (made by Syntec Co., Ltd.) (same for the following experiment). The results are shown in Table 6.

At the time of preparation of the retardation film on the photo-alignment film produced using the polymers 8 and 9, the retention rate of the birefringence rate before and after the baking process was evaluated.

The results are shown in Table 7.

(Industrial availability)

The copolymerizable (meth) acrylic acid polymer of the present invention is useful as a raw material of a photoalignment film and a retardation film using the same, and the photoalignment film and the retardation film of the present invention are particularly various OA devices such as computers and facsimile. It is useful as an optical element of liquid crystal display devices, such as a mobile telephone, an electronic notebook, a liquid crystal television, and a video camera.

Claims (8)

The compound of formula (I)

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, and ring A and ring B are each independently,

[However, each of X ^{1 to} X ³⁸ is independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group.]
Z is a group represented by -CH = CHCOO- (trans) or -N = N-, p and q are each independently an integer of 1-12, m and n are It is the mole fraction of each monomer which occupies the copolymer which satisfy | fills the relationship of 0.65 <= m <= 0.95, 0.05 <= n <= 0.35, and m + n = 1. The copolymerizable (meth) acrylic acid polymer which has a repeating unit represented by]. General formula (IA)

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, each of X ^{1A to} X ^4A is each independently, A hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group, and ring B is

[However, X ^{1B to} X ^4B And X ^{31B to} X ^38B are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group.]
Z is a group represented by -CH = CHCOO- (trans) or -N = N-, p and q are each independently an integer of 1-12, m and n are It is the mole fraction of each monomer in the copolymer which satisfies the relationship of 0.65≤m≤0.95, 0.05≤n≤0.35 and m + n = 1.]
A copolymerizable (meth) acrylic acid polymer having a repeating unit represented by Formula (Ia)

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, each of X ^{1A to} X ^4A is each independently hydrogen An atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group, and ring B is

[However, each of X ^{1B to} X ^4B and X ^{31B to} X ^38B is each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group.]
P and q are each independently an integer of any one of 1 to 12, and m and n are copolymers satisfying a relationship of 0.65 ≦ m ≦ 0.95, 0.05 ≦ n ≦ 0.35, and m + n = 1 Mole fraction of each monomer in
A copolymerizable (meth) acrylic acid polymer having a repeating unit represented by Formula (Ib)

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, X ^{1A to} X ^4A And X3 ^1B ~X ^38B each are independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group, respectively, and p and q are each independently, are any integer of 1~12, m, and n are , Mole fraction of each monomer in a copolymer satisfying the relationship of 0.65 ≦ m ≦ 0.95, 0.05 ≦ n ≦ 0.35, and m + n = 1.]
A copolymerizable (meth) acrylic acid polymer having a repeating unit represented by General formula (Ic)

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group or a phenyl group substituted with a group selected from an alkyl group, an alkoxy group, a cyano group and a halogen atom, X ^{1A to} X ^4A And each of X ^{1B to} X ^4B is, independently, a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group, and Z is a group represented by -CH = CHCOO- (trans) or -N = N-, p and q are each independently integers in any one of 1-12, m and n are the mole fractions of each monomer which occupies the copolymer which satisfy | fills the relationship of 0.65 <= m <0.95, 0.05 <= n <0.35, and m + n = 1 to be.〕
A copolymerizable (meth) acrylic acid polymer having a repeating unit represented by The composition for photo-alignment films containing the copolymerizable (meth) acrylic-acid polymer of any one of Claims 1-5. The optical alignment film | membrane which irradiated the light which has anisotropy to the film | membrane which consists of a composition for photo-alignment films of Claim 6, and heats it again and generate | occur | produces liquid-crystal orientation capability. The retardation film which orientated the liquid crystalline compound on the photo-alignment film of Claim 7.