JP4968422B2 - Method for producing liquid crystal alignment film - Google Patents

Description

The present invention also relates to the manufacture how the liquid crystal alignment film. More specifically, without the rubbing process relates to the production how polarized light or non-polarized light when irradiated with radiation capable of imparting the liquid crystal alignment capability liquid crystal alignment film.

  Conventionally, a nematic liquid crystal having positive dielectric anisotropy is sandwiched with a substrate with a transparent electrode having a liquid crystal alignment film, and the major axis of liquid crystal molecules is continuously twisted between 0 and 360 degrees between the substrates as necessary. Liquid crystal display elements having liquid crystal cells such as TN (twisted nematic), STN (super twisted nematic), and IPS (in-plane switching) are known (see Patent Documents 1 and 2). .

  As a means for aligning the liquid crystal in such a liquid crystal cell, an organic film (liquid crystal alignment film) is formed on the surface of the substrate, and then the surface of the organic film is rubbed in one direction with a cloth material such as rayon. (A method of applying a rubbing treatment), a method of obliquely depositing silicon oxide on the surface of a substrate, a method of forming a monomolecular film having a long chain alkyl group using the Langmuir-Blodgett method (LB method), etc. There is. Among these, from the viewpoints of substrate size, liquid crystal alignment uniformity, processing time, and processing cost, it is common to provide liquid crystal alignment ability by rubbing.

  However, if the alignment of the liquid crystal is performed by rubbing, dust is likely to be generated in the process or static electricity is likely to be generated, so that dust adheres to the alignment film surface and causes display defects. there were. In particular, in the case of a substrate having a TFT (Thin Film Transistor) element, there has been a problem that the circuit damage of the TFT element occurs due to the generated static electricity, resulting in a decrease in yield. Further, in liquid crystal display elements that will be further refined in the future, unevenness occurs on the surface of the substrate as the density of pixels increases, so that uniform rubbing is a problem.

  As another means of aligning the liquid crystal in the liquid crystal cell, there is a photo-alignment method that imparts liquid crystal alignment ability by irradiating polarized or non-polarized radiation to a photosensitive thin film such as polyvinyl cinnamate or polyimide formed on the substrate surface. Are known. According to this method, uniform liquid crystal alignment can be realized without generating static electricity or dust (see Patent Documents 3 to 12).

  Further, as an operation mode of a liquid crystal display element different from the above, a vertical (homeotropic) alignment mode in which liquid crystal molecules having negative dielectric anisotropy are aligned perpendicularly to a substrate is also known. In this operation mode, when a voltage is applied between the substrates and the liquid crystal molecules are tilted in the direction parallel to the substrate, the liquid crystal molecules must be tilted from the substrate normal direction to one direction in the substrate surface. There is. As a means for this, for example, a method of providing protrusions on the substrate surface, a method of providing stripes on the transparent electrode, or using a rubbing alignment film, liquid crystal molecules are slightly directed from the substrate normal direction to one direction in the substrate surface. A method of tilting (pretilting) has been proposed.

  The photo-alignment method is known to be useful as a method for controlling the tilt direction of liquid crystal molecules in a vertical alignment mode liquid crystal display element. That is, it is known that the tilt direction of the liquid crystal molecules at the time of voltage application can be uniformly controlled by using a vertical alignment film imparted with an alignment regulating force by a photo-alignment method (see Patent Documents 11 to 14).

  Conventionally, in the display, optoelectronics, and optical fields, optical members such as polarizing plates, phase difference plates, and optically rotatory optical films have been used. These optical members have various uses. For example, in addition to being widely used as a member such as a polarizing plate, a compensation plate, and a viewing angle improving film in a liquid crystal display device, they are also used as a phase difference plate for an optical pickup element in an optical disk device. It has been.

  As a method for producing such an optical member, many methods such as a method using a stretched and oriented resin film have been conventionally known. However, the optical member manufactured by such a method has the same optical characteristics over the entire surface, and it has not been possible to obtain an optical member having different optical characteristics in different regions within the surface.

  On the other hand, two prior inventions (see Patent Documents 15 to 16) clarified a method for fixing an alignment state after aligning a liquid crystal substance having an optical function on a liquid crystal alignment film manufactured by a photo-alignment method. ing. By this method, an optical member having different optical characteristics in different regions within the surface can be easily manufactured.

As described above, the liquid crystal alignment film manufactured by the photo-alignment method can be effectively applied to a liquid crystal display element and an optical member. However, the conventional photo-alignment method using polyvinyl cinnamate, polyimide, or the like has a problem that a large amount of radiation is necessary to obtain liquid crystal alignment ability.
JP 56-91277 A JP-A-1-120528 JP-A-6-287453 JP-A-10-251646 JP-A-11-2815 JP 11-152475 A JP 2000-144136 A JP 2000-319510 A JP 2000-281724 A JP-A-9-297313 JP 2003-307736 A JP 2004-163646 A JP-A-9-21468 JP 2003-114437 A JP-A-6-289374 JP 2004-20658 A

An object of the present invention is to provide a liquid crystal aligning agent (hereinafter referred to as “photo-aligning agent”) used for forming a liquid crystal aligning film capable of imparting liquid crystal aligning ability by irradiation with polarized or non-polarized radiation without performing a rubbing treatment. Is also disclosed ).

Another object of the present invention is to disclose a liquid crystal aligning agent used for forming a liquid crystal aligning film that requires a small amount of radiation for imparting liquid crystal aligning ability.

  Still another object of the present invention is to provide a method for producing a liquid crystal alignment film.

  Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the above objects and advantages of the present invention are :
Tetracarboxylic acid dianhydride represented by the following following formula (I)

（式中、Ｒ^１、Ｒ^２、Ｒ^３およびＲ^４は、それぞれ、水素原子または炭素数１〜１５の有機基を示す。但し、Ｒ^１、Ｒ^２、Ｒ^３およびＲ^４のうちの少なくとも１つは有機基であるものとする）

(Wherein R ¹ , R ² , R ³ and R ⁴ each represent a hydrogen atom or an organic group having 1 to 15 carbon atoms, provided that at least one of R ¹ , R ² , R ³ and R ⁴ One is an organic group)

A polyamic acid having the amic acid structure derived from a diamine, and a thin film made of photo-alignment agent you containing a compound having two or more epoxy groups in the molecule, although the thin film is formed on a substrate, the This is achieved by a method for producing a liquid crystal alignment film, which is characterized by imparting liquid crystal alignment ability by irradiating non-polarized radiation obliquely with respect to the substrate surface .

When the photo-alignment agent in the present invention is used, a liquid crystal alignment film can be obtained with a smaller radiation dose than in the case of using the conventional photo-alignment method. Therefore, when this liquid crystal alignment film is applied to a liquid crystal display element, a liquid crystal display element having excellent display characteristics can be manufactured at a lower cost than before. Moreover, when the liquid crystal aligning film in this invention is applied to manufacture of an optical member, the optical member excellent in in-plane uniformity can be manufactured cheaply than before. Therefore, these liquid crystal display elements and optical members can be effectively applied to various devices, and are suitable for devices such as desk calculators, watches, table clocks, counting display boards, word processors, personal computers, liquid crystal televisions, or optical disk devices. Used for.

  Hereinafter, the present invention will be described in detail. The polyamic acid used in the present invention can be obtained by reacting a tetracarboxylic dianhydride and a diamine compound in an organic solvent. These polyamic acids may be used as a mixture of two or more.

[Tetracarboxylic dianhydride]
The tetracarboxylic dianhydride used in the present invention is represented by the above formula (I). In the formula (I), R ¹ , R ² , R ³ and R ⁴ each represent a hydrogen atom or an organic group having 1 to 30 carbon atoms. However, at least one of R ¹ , R ² , R ³ and R ⁴ is an organic group.

As the organic group having 1 to 30 carbon atoms represented by R ¹ , R ² , R ³ or R ⁴ , specifically, an alkyl group having 1 to 30 carbon atoms, a cycloalkyl group having 1 to 30 carbon atoms, A C1-C30 alkoxyl group, a phenyl group, and the following formula (II)

（但し、Ｚは、エーテル結合、エステル結合、フェニレン基、および、これらの基を２つ以上連結して得られる基、からなる群より選ばれる結合基を表し、ｎは２または３であり、Ｘは炭素数１〜２５のアルキル基を表す。）

(However, Z represents a bonding group selected from the group consisting of an ether bond, an ester bond, a phenylene group, and a group obtained by linking two or more of these groups, and n is 2 or 3. X represents an alkyl group having 1 to 25 carbon atoms.)

The group represented by these can be mentioned. Among these, a C1-C30 alkyl group, a phenyl group, and group represented by the said formula (II) are preferable. Among the groups represented by the alkyl group having 1 to 6 carbon atoms, the phenyl group, and the above formula (II), the groups represented by the following formulas (i) to (iv) are more preferable, and the methyl group is particularly preferable. preferable.

_{-O- (CH 2 CH 2 O)} 2 -CH 2 CH 3 (i)

_{-O- (CH 2 CH 2 O)} 2 -CH 3 (ii)

  Examples of the tetracarboxylic dianhydride represented by the above formula (I) include 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1, 2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-diphenyl-1,2 , 3,4-cyclobutanetetracarboxylic dianhydride and the following formulas (1) to (4):

The compound represented by these can be mentioned. Of these, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,3-diphenyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride are preferred, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride is particularly preferred.

  In the polyamic acid used in the present invention, the content ratio of the tetracarboxylic dianhydride represented by the formula (I) and the amic acid repeating unit derived from the diamine is preferably 0. It is 1-100 mol%, More preferably, it is 5-95 mol%, Most preferably, it is 50-90 mol%.

In the polyamic acid used in the present invention, other tetracarboxylic dianhydrides can be used in combination with the tetracarboxylic dianhydride represented by the formula (I). Examples of such other tetracarboxylic dianhydrides include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride. 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3 ′, 4,4′-dicyclohexyltetracarboxylic dianhydride Anhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6-tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 3, 5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 1,3,3a, 4,5 9b Hexahydro-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5 Methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5 Ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-7- Methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-7- Ethyl-5 (tetrahydro-2,5-dioxo-3-fura Nyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5 (tetrahydro-2,5-dioxo-3- Furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-ethyl-5 (tetrahydro-2,5-dioxo-3- Furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5,8-dimethyl-5 (tetrahydro-2,5-dioxo-) 3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid Anhydride, bicyclo [2 . 2 . 2] -Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 3-oxabicyclo [3 . 2 . 1] octane-2,4-dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′-dione), tetracarboxylic dianhydrides represented by the following formulas (III) and (IV), etc. Alicyclic tetracarboxylic dianhydrides;

（式中、Ｒ^５およびＲ^７は、芳香環を有する２価の有機基を示し、Ｒ^６およびＲ^８は、水素原子またはアルキル基を示し、複数存在するＲ^６およびＲ^８は、それぞれ同一でも異なっていてもよい。）

(In the formula, R ⁵ and R ⁷ represent a divalent organic group having an aromatic ring, R ⁶ and R ⁸ represent a hydrogen atom or an alkyl group, and a plurality of R ⁶ and R ⁸ are the same. But it may be different.)

An aliphatic tetracarboxylic dianhydride such as butanetetracarboxylic dianhydride;
Pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 1,4,5, 8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic dianhydride, 3,3 ′, 4,4′-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ′, 4,4′-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4,4′-bis ( 3,4-dicar Boxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidene diphthalic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, bis (Phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4 , 4′-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4′-diphenylmethane dianhydride, ethylene glycol-bis (anhydro trimellitate), propylene glycol-bis (anhydro trimellitate) 1,4-butanediol-bis (anhydrotrimellitate), 1,6-hexanediol-bis (anhydride) Trimellitate), 1,8-octanediol-bis (anhydrotrimellitate), 2,2-bis (4-hydroxyphenyl) propane-bis (anhydrotrimellitate), the following formulas (5) to (8) An aromatic tetracarboxylic dianhydride such as an aromatic tetracarboxylic dianhydride having a steroid skeleton represented by These may be used alone or in combination of two or more.

Of these, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride 5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1, 2,5,6-tetracarboxylic dianhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-dianhydride, 1,3,3a, 4,5,9b -Hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8 -Methyl-5- (tetra Dro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5,8-dimethyl-5 -(Tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, bicyclo [2 . 2 . 2] -Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 3-oxabicyclo [3 . 2 . 1] Octane-2,4-dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′-dione), among the compounds represented by the above formula (III), the following formulas (9) to (11) A compound represented by the following formula (12) among the compounds represented by the formula (IV):

Butanetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride And 1,4,5,8-naphthalenetetracarboxylic dianhydride are preferable from the viewpoint of exhibiting good liquid crystal orientation and electrical characteristics. Among them, pyromellitic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3- Furanyl) -naphtho [1,2-c] furan-1,3-dione and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo- 3-furanyl) -naphtho [1,2-c] furan-1,3-dione is preferred. These other tetracarboxylic dianhydrides may be used alone or in combination of two or more.

[Diamine compound]
Examples of the diamine compound used for the synthesis of the polyamic acid include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, 4,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl sulfone, 3,3′-dimethyl-4,4′-diaminobiphenyl, 4,4′-diaminobenzanilide, 4,4′-diaminodiphenyl ether, 1,5-diaminonaphthalene, 2, 2'-dimethyl-4,4'-diaminobiphenyl, 5-amino-1- (4'-aminophenyl) -1,3,3-trimethylindane, 6-amino-1- (4'-aminophenyl)- 1,3,3-trimethylindane, 3,4'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, , 4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexa Fluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] sulfone, 1,4-bis (4-aminophenoxy) benzene, 1 , 3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -10-hydroanthracene, 2,7-diaminofluorene, 9 , 9-bis (4-aminophenyl) fluorene, 4,4′-methylene-bis (2-chloroaniline), 2,2 ′, 5,5′-tetra Loro-4,4′-diaminobiphenyl, 2,2′-dichloro-4,4′-diamino-5,5′-dimethoxybiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 1,4 , 4 ′-(p-phenyleneisopropylidene) bisaniline, 4,4 ′-(m-phenyleneisopropylidene) bisaniline, 2,2′-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] Such as hexafluoropropane, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 4,4′-bis [(4-amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl, etc. Aromatic diamines;

1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1 , 4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindanylene methylenediamine, tricyclo [6.2.1.0 ^2,7 ] -undecylenedimethyldiamine, 4 Aliphatic and cycloaliphatic diamines such as 4,4'-methylenebis (cyclohexylamine);

2,3-diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 5,6-diamino-2,3-dicyanopyrazine, 5,6-diamino-2,4 -Dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 1,4-bis (3-aminopropyl) piperazine, 2,4-diamino-6-isopropoxy-1,3 , 5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine, 2,4-diamino-6-methyl -S-triazine, 2,4-diamino-1,3,5-triazine, 4,6-diamino-2-vinyl-s-triazine, 2,4-diamino-5-phenylthiazole, 2,6- Aminopurine, 5,6-diamino-1,3-dimethyluracil, 3,5-diamino-1,2,4-triazole, 6,9-diamino-2-ethoxyacridine lactate, 3,8-diamino-6 Two molecules in the molecule such as phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, bis (4-aminophenyl) phenylamine and compounds represented by the following formulas (V) to (VI) A diamine having a primary amino group and a nitrogen atom other than the primary amino group;

（式中、Ｒ^９は、ピリジン、ピリミジン、トリアジン、ピペリジンおよびピペラジンから選ばれる窒素原子を含む環構造を有する１価の有機基を示し、Ｘは２価の有機基を示す。）

(Wherein R ⁹ represents a monovalent organic group having a ring structure containing a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine, and X represents a divalent organic group.)

（式中、Ｒ^１０は、ピリジン、ピリミジン、トリアジン、ピペリジンおよびピペラジンから選ばれる窒素原子を含む環構造を有する２価の有機基を示し、Ｘは２価の有機基を示し、複数存在するＲ^１０は、同一でも異なっていてもよい。）

Wherein R ¹⁰ represents a divalent organic group having a ring structure containing a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine, X represents a divalent organic group, and a plurality of R ¹⁰ may be the same or different.)

  Monosubstituted phenylenediamines represented by the following formula (VII); diaminoorganosiloxanes represented by the following formula (VIII);

（式中、Ｒ^１１は、−Ｏ−、−ＣＯＯ−、−ＯＣＯ−、−ＮＨＣＯ−、−ＣＯＮＨ−および−ＣＯ−から選ばれる２価の有機基を示し、Ｒ^１２は、ステロイド骨格、トリフルオロメチル基およびフルオロ基から選ばれる基を有する１価の有機基または炭素数６〜３０のアルキル基を示す。）

(Wherein R ¹¹ represents a divalent organic group selected from —O—, —COO—, —OCO—, —NHCO—, —CONH— and —CO—, and R ¹² represents a steroid skeleton, A monovalent organic group having a group selected from a fluoromethyl group and a fluoro group or an alkyl group having 6 to 30 carbon atoms is shown.)

（式中、Ｒ^１３は炭素数１〜１２の炭化水素基を示し、複数存在するＲ^１３は、それぞれ同一でも異なっていてもよく、ｐは１〜３の整数であり、ｑは１〜２０の整数である。）

(In the formula, R ¹³ represents a hydrocarbon group having 1 to 12 carbon atoms, and a plurality of R ¹³ may be the same or different, p is an integer of 1 to 3, and q is 1 to 20) Is an integer.)

  Examples thereof include compounds represented by the following formulas (13) to (17). These diamine compounds can be used alone or in combination of two or more.

（式中、ｙは２〜１２の整数であり、ｚは１〜５の整数である。）

(In the formula, y is an integer of 2 to 12, and z is an integer of 1 to 5.)

Among these, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 4,4′-diaminodiphenyl ether, 2, 2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2 , 2-bis (4-aminophenyl) hexafluoropropane, 4,4 ′-(p-phenylenediisopropylidene) bisaniline, 4,4 ′-(m-phenylenediisopropylidene) bisaniline, 1,4-cyclohexanediamine 4,4′-methylenebis (cyclohexylamine), 1,4-bis (4-amino) Enoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, the above formula (VII Monosubstituted phenylenediamines represented by:
Further, compounds represented by the above formulas (13) to (17) are preferable, and among the mono-substituted phenylenediamines represented by the above formula (VII), 1- (2,5-diaminophenoxy) hexadecane, -(2,5-diaminophenoxy) octadecane and compounds represented by the following formulas (18) to (27) are particularly preferred.

  In addition, 1- (2,5-diaminophenoxy) hexadecane, 1- (2,5-diaminophenoxy) octadecane, or a compound represented by the following formulas (18) to (27) is 2 in 100 mol of all diamines. It is particularly preferred that it be contained in moles.

［チルト成分］
本発明における液晶配向剤をＴＮ（Ｔｗｉｓｔｅｄ Ｎｅｍａｔｉｃ）型、ＳＴＮ（Ｓｕｐｅｒ Ｔｗｉｓｔｅｄ Ｎｅｍａｔｉｃ）型、ＶＡ（Ｖｅｒｔｉｃａｌ Ａｌｉｇｎｍｅｎｔ）型などの液晶セルを有する液晶表示素子に適用する場合には、当該液晶配向剤に含有されるポリアミック酸の合成反応に供されるテトラカルボン酸二無水物またはジアミン化合物として、炭素数１０〜３０のアルキル基、炭素数１０〜３０の脂環式骨格含有基および炭素数２以上のフッ素含有有機基よりなる群より選ばれる少なくとも１種の基を有する化合物（以下、「チルト成分」ともいう）を用いることにより、垂直配向性またはプレチルト角発現性を付与することが好ましい。なお、本発明における「プレチルト角」とは、基板面と平行な方向からの液晶分子の傾きの角度を表す。

[Tilt component]
When the liquid crystal aligning agent in the present invention is applied to a liquid crystal display element having a liquid crystal cell such as a TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, VA (Vertical Alignment) type, etc., it is contained in the liquid crystal aligning agent. As a tetracarboxylic dianhydride or diamine compound to be used in the polyamic acid synthesis reaction, an alkyl group having 10 to 30 carbon atoms, an alicyclic skeleton-containing group having 10 to 30 carbon atoms, and fluorine having 2 or more carbon atoms By using a compound having at least one group selected from the group consisting of a contained organic group (hereinafter also referred to as “tilt component”), it is preferable to impart vertical alignment or pretilt angle expression. The “pretilt angle” in the present invention represents an angle of inclination of liquid crystal molecules from a direction parallel to the substrate surface.

  Specifically, the tilt component is represented by the formula (VII) among the compounds represented by the above formulas (5) to (8) among the tetracarboxylic acid anhydride and the diamine compound. Examples include mono-substituted phenylenediamines and compounds represented by the above formulas (13) to (15).

When the tilt component is used in the synthesis of the polyamic acid in the present invention, the ratio of the tilt component in the total amount of the tetracarboxylic dianhydride and the diamine compound used is preferably 0 when used in the vertical alignment mode. 0.1 to 75 mol%, more preferably 1 to 50 mol%, and particularly preferably 3 to 25 mol%. Moreover, when using for modes other than vertical alignment, although a preferable content rate changes with target pretilt angles, the upper limit becomes like this. Preferably it is 20 mol%.

[Synthetic reaction of polyamic acid]
The ratio of the tetracarboxylic dianhydride and the diamine compound used for the polyamic acid synthesis reaction is such that the acid anhydride group of the tetracarboxylic dianhydride is 0.1 relative to 1 equivalent of the amino group contained in the diamine compound. A ratio of 2 to 2 equivalents is preferable, and a ratio of 0.3 to 1.2 equivalents is more preferable.

  The synthetic reaction of polyamic acid is preferably carried out in an organic solvent under a temperature condition of -20 to 150 ° C, more preferably 0 to 100 ° C. Here, the organic solvent is not particularly limited as long as it can dissolve the synthesized polyamic acid. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide And aprotic polar solvents such as γ-butyrolactone, tetramethylurea and hexamethylphosphortriamide; and phenolic solvents such as m-cresol, xylenol, phenol and halogenated phenol. The amount of organic solvent used (a) is preferably such that the total amount (b) of tetracarboxylic dianhydride and diamine compound is 0.1 to 30% by weight based on the total amount (a + b) of the reaction solution. It is preferable that the amount is small.

[Poor solvent]
Alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, etc., which are poor solvents for polyamic acid, may be used in combination with the organic solvent as long as the resulting polyamic acid does not precipitate. it can. Specific examples of the poor solvent include, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether, ethyl lactate, butyl lactate, Acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, diethyl malonate, diethyl ether, ethylene glycol methyl ether, ethylene Glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n- Chill ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1 , 4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene and the like.

  As described above, a reaction solution obtained by dissolving polyamic acid is obtained. The reaction solution is poured into a large amount of poor solvent to obtain a precipitate, and the precipitate is dried under reduced pressure to obtain a polyamic acid. The polyamic acid can be purified by dissolving the polyamic acid again in an organic solvent and then precipitating with a poor solvent once or several times.

[Terminal-modified polyamic acid]
The polyamic acid may be of a terminal modified type with a controlled molecular weight. By using this terminal-modified polyamic acid, the coating characteristics of the liquid crystal aligning agent can be improved without impairing the effects of the present invention. Such a terminal-modified type can be synthesized, for example, by adding an acid monoanhydride, a monoamine compound, a monoisocyanate compound or the like to the reaction system when synthesizing the polyamic acid. Here, as the acid monoanhydride, for example, maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride , N-hexadecyl succinic anhydride and the like. Examples of monoamine compounds include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, and n-undecylamine. N-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine, etc. Can do. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

[Photo-alignment agent]
The photo-alignment agent in the present invention is usually constituted by dissolving the above polyamic acid and a compound having two or more epoxy groups in the molecule in an organic solvent. Examples of the organic solvent constituting the photoalignment agent in the present invention include the solvents exemplified as those used for the polyamic acid synthesis reaction. Moreover, the poor solvent illustrated as what can be used together in the case of the synthesis reaction of a polyamic acid can also be selected suitably, and can be used together.

The solid content concentration in the photo-alignment agent in the present invention is selected in consideration of viscosity, volatility, etc., but is preferably in the range of 1 to 10% by weight. That is, the photo-alignment agent in the present invention is applied to the substrate surface to form a coating film that becomes a liquid crystal alignment film. When the solid content concentration is less than 1% by weight, the coating film thickness is It is too small to obtain a good liquid crystal alignment film. When the solid content concentration exceeds 10% by weight, it is difficult to obtain a good liquid crystal alignment film due to an excessive film thickness, and the viscosity of the photo-alignment agent increases and the coating properties tend to be inferior. Moreover, the temperature at the time of preparing the photo-alignment agent in the present invention is preferably 0 ° C to 200 ° C, more preferably 20 ° C to 60 ° C.

The photo-alignment agent in the present invention contains a compound having two or more epoxy groups in the molecule (hereinafter also referred to as “epoxy group-containing compound”) in an amount of 100 parts by weight of polyamic acid in order to improve the stability and electrical properties of the film. It is preferable to contain 5 parts by weight or more based on the above.

  Examples of the epoxy group-containing compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6 -Hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, bisphenol A diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N, N ′, N′-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N Low molecular epoxy compounds such as N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane, bisphenol A type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, cycloaliphatic epoxy resins And epoxy group-containing polymers such as glycidyl ester epoxy resins, glycidyl diamine epoxy resins, heterocyclic epoxy resins, and epoxy group-containing acrylic resins.

  The content of the epoxy compound is preferably 5 parts by weight or more, more preferably 10 to 100 parts by weight, and still more preferably 20 to 80 parts by weight with respect to 100 parts by weight of the polyamic acid contained in the photoalignment agent. It is. Furthermore, when using the aforementioned polyfunctional epoxy-containing compound, a basic catalyst such as 1-benzyl-2-methylimidazole can be added for the purpose of efficiently causing a crosslinking reaction.

In addition, the photo-alignment agent in the present invention may contain a functional silane-containing compound. Examples of such functional silane-containing compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, and N- (2-aminoethyl). -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-amino Propyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl- , 4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N -Bis (oxyethylene) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, etc. can be mentioned.

  The blending ratio of these functional silane-containing compounds is preferably 40 parts by weight or less, more preferably 4 parts by weight or less with respect to 100 parts by weight of the polyamic acid.

As a method for forming a liquid crystal alignment film in the liquid crystal alignment film present invention include, for example, the following method. First, the photo-alignment agent in the present invention is applied to the transparent conductive film side of the substrate provided with the transparent conductive film by a roll coater method, a spinner method, a printing method, or the like, and preferably heated at a temperature of 40 to 200 ° C. Form a coating film. The film thickness of the coating film is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm, as a solid content. As the substrate, for example, a transparent substrate made of glass or a plastic film such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, or polycarbonate can be used. As the transparent conductive film, an indium oxide-based film or a tin oxide-based film can be used, and a photolithography method, a printing method, or the like can be applied to patterning the transparent conductive film. In applying the liquid crystal aligning agent, a functional silane-containing compound or titanate may be applied in advance on the substrate and the transparent conductive film in order to further improve the adhesion between the substrate and the transparent conductive film and the coating film. it can.

Subsequently, the coating film is irradiated with non- polarized radiation, and in some cases, a heat treatment is further performed at a temperature of 150 to 250 ° C. to impart liquid crystal alignment ability. As the radiation, ultraviolet rays and visible rays having a wavelength of 150 nm to 800 nm can be used. Among these, ultraviolet rays having a wavelength of 150 nm to 450 nm are preferable, and ultraviolet rays having a wavelength of 200 nm to 300 nm are more preferable. As the radiation, non-polarized light is preferable because it is more easily obtained than linearly polarized light or partially polarized light . When irradiating non- polarized radiation, the direction of irradiation needs to be oblique to the substrate surface. Moreover, in order to improve liquid crystal aligning ability, you may irradiate, heating a board | substrate to 50-250 degreeC. Dose of the radiation is preferably in the range of 1~10,000mJ / cm ^2, more preferably in the range of 10~1,000mJ / cm ^2, in the range of 20~100mJ / cm ² It is particularly preferred.

  In addition, upon irradiation with radiation, for the purpose of preparing liquid crystal alignment films having different orientation directions in different regions within the plane, radiation having different polarization state, optical axis direction, and energy is applied to each region within the surface. Can be irradiated. As a method of changing the polarization state of the irradiated radiation, the direction of the optical axis, and the energy in-plane, the method of performing irradiation through a photomask, while changing the light intensity, the incident angle, etc. as necessary, Examples thereof include a method of sweeping the coating film with light. These methods can be used alone or in combination. Further, one or both of these methods may be combined with the batch irradiation on the entire surface of the substrate.

As the light source, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, or an excimer laser can be used. The ultraviolet rays in the preferable wavelength region can be obtained by means of using a filter or a diffraction grating in combination with the light source.
In addition, it is thought that the photoalignment agent in this invention has changed the polyamic acid part or all into the polyimide by heating.

Liquid crystal display element The liquid crystal display element in this invention is manufactured as follows, for example. First, the two substrates on which the liquid crystal alignment film is formed are opposed to each other so that the polarization direction of the linearly polarized radiation previously irradiated becomes a predetermined angle and bonded together with a sealant, and then the liquid crystal is injected, and the injection hole is formed. The liquid crystal cell is assembled by sealing. At this time, it is desirable to remove the flow alignment at the time of liquid crystal injection by heating the cell to a temperature at which the liquid crystal takes an isotropic phase and then cooling it to room temperature. Next, a polarizing plate is attached to both surfaces of the cell so that the polarizing direction of the polarizing plate forms a predetermined angle with the polarizing direction of the linearly polarized radiation, thereby obtaining a liquid crystal display element. When the liquid crystal alignment film is horizontally oriented, the TN type, STN type, or IPS type can be arbitrarily adjusted by adjusting the angle formed by the polarization direction of the linearly polarized radiation to be irradiated and the angle between each substrate and the polarizing plate. A liquid crystal display element such as can be obtained. On the other hand, when the liquid crystal alignment film is vertically aligned, the cell is configured so that the directions of easy alignment axes of the two substrates on which the liquid crystal alignment film is formed are parallel, and a polarizing plate is attached to the polarizing plate. A liquid crystal display element having a vertical alignment type liquid crystal cell can be obtained by bonding so that the direction forms an angle of 45 degrees with the easy alignment axis.

  As the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used.

  As the liquid crystal, nematic liquid crystal, smectic liquid crystal, or the like can be used. In the case of a TN type liquid crystal cell, STN type liquid crystal cell and IPS type liquid crystal cell, those composed of liquid crystal molecules having positive dielectric anisotropy to form a nematic type liquid crystal are preferable. Biphenyl liquid crystal, phenyl cyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenyl cyclohexane liquid crystal, pyrimidine liquid crystal, dioxane liquid crystal, bicyclooctane liquid crystal, or cubane liquid crystal are used. Further, for example, a cholesteric liquid crystal such as cholesteryl chloride, cholesteryl nonate and cholesteryl carbonate, a chiral agent such as that sold under the trade name C-15 or CB-15 (manufactured by Merck & Co., Inc.) and the like are added to the liquid crystal. You can also Furthermore, a ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate can also be used. In the case of a vertically aligned liquid crystal cell, a liquid crystal molecule having negative dielectric anisotropy that forms a nematic liquid crystal is preferable. For example, dicyanobenzene liquid crystal, pyridazine liquid crystal, Schiff base liquid crystal, azoxy liquid crystal Type liquid crystal, biphenyl type liquid crystal, or phenylcyclohexane type liquid crystal is used.

  As a polarizing plate used outside the liquid crystal cell, for example, a polarizing plate formed by sandwiching a polarizing film called an H film that absorbs iodine while stretching and aligning polyvinyl alcohol with a cellulose acetate protective film, or a polarizing film composed of the H film itself A board etc. can be mentioned.

An optical member in the optical member present invention, for example, can be manufactured according, by various methods in Patent Documents 16. Among them, a particularly preferable method is a method in which a polymerizable liquid crystal material is aligned on the liquid crystal alignment film in the present invention and then solidified by polymerizing the material by radiation irradiation.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. The pretilt angle, voltage holding ratio, and retardation in Examples and Comparative Examples were evaluated by the following methods.

[Pretilt angle]
T.A. J. et al. Scheffer et. al. J. et al. Appl. Phys. vo. 19, p. In accordance with the method described in 2013 (1980), it was measured by a crystal rotation method using a He—Ne laser beam.

[Orientation of liquid crystal]
The presence / absence of an abnormal domain when the voltage was turned on / off (applied / released) to the liquid crystal display element was observed with a polarizing microscope, and the case where there was no abnormal domain was determined as “good”.

[Voltage holding ratio]
A voltage of 5 V was applied to the liquid crystal display element with an application time of 60 microseconds and a span of 167 milliseconds, and then the voltage holding ratio after 167 milliseconds from release of application was measured. The measuring apparatus used was VHR-1 manufactured by Toyo Corporation. The case where the voltage holding ratio was 90% or more was judged as good, and the other cases were judged as bad.

[Retardation]
Using OMS-J3 manufactured by Chuo Seiki Co., Ltd., measurement was performed by the Senarmon method.

Synthesis Examples 1-8
In N-methyl-2-pyrrolidone, the composition shown in Table 1, in the order of diamine compound (shown as “diamine” in the table), tetracarboxylic dianhydride (shown as “acid anhydride” in the table). In addition, a solution having a solid content concentration of 15% by weight was prepared and reacted at room temperature for 6 hours. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Then, the polyamic acid polymer (A-1 to A-8) shown in Table 1 was obtained by washing with methyl alcohol and drying at room temperature under reduced pressure for 15 hours.

The diamine compounds and tetracarboxylic dianhydrides in Table 1 are as follows.

<Diamine compound>
D-1: p-phenylenediamine D-2: 4,4′-diaminodiphenyl ether D-3: 1- (2,5-diaminophenoxy) octadecane D-4: Compound D- represented by the above formula (18) 5: Compound represented by formula (19) <Tetracarboxylic dianhydride>
T-1: 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride T-2: 1,2,3,4-cyclobutanetetracarboxylic dianhydride

Comparative Synthesis Example 0.1 mol (21.8 g) of pyromellitic dianhydride and 0.1 mol (20.0 g) of 4,4′-diaminodiphenyl ether were dissolved in 300 g of N-methyl-2-pyrrolidone at 60 ° C. The reaction was performed for 6 hours. The reaction mixture was then poured into a large excess of methanol to precipitate the reaction product. Thereafter, it was washed with methanol and dried under reduced pressure at 40 ° C. for 15 hours to obtain 41 g (yield 98%) of polyamic acid (hereinafter referred to as “polymer Aa”).

Reference example 1
The polymer Aa obtained in the comparative synthesis example was dissolved in N-methyl-2-pyrrolidone to obtain a solution having a solid content concentration of 2.5% by weight, and this solution was filtered through a filter having a pore size of 1 μm. Hereinafter, “liquid crystal aligning agent P”) was prepared. This solution was applied onto the transparent electrode surface of the glass substrate with a transparent electrode made of an ITO film using a spinner so that the film thickness became 0.1 μm, and dried at 180 ° C. for 1 hour to form a thin film. The thin film was rubbed at a rotational speed of 500 rpm and a stage moving speed of 1 cm / sec using a rubbing machine having a roll around which a nylon cloth was wound. Next, with respect to the pair of substrates subjected to the rubbing treatment, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm is screen-printed on the surface on which the liquid crystal alignment film is formed, and then the rubbing direction becomes antiparallel. The substrate was superposed and pressure-bonded, and the adhesive was thermally cured at 150 ° C. for 1 hour. Next, a nematic liquid crystal (ZLI-1565 manufactured by Merck & Co., Inc.) was filled between the pair of substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an epoxy adhesive. Furthermore, in order to remove the flow alignment at the time of liquid crystal injection, this was heated at 150 ° C. and then gradually cooled to room temperature. Next, a polarizing plate was bonded to both sides of the substrate so that the polarization directions were orthogonal to each other and at an angle of 45 degrees with the rubbing direction of the liquid crystal alignment film. The orientation of was good. When a voltage of 5 V was applied, a change in brightness of the liquid crystal display element was observed in response to ON / OFF of the applied voltage. Further, the pretilt angle in this liquid crystal cell was 0.5 °, and the voltage holding ratio was judged to be good.

Reference example 2
In the same manner as in Reference Example 1, the liquid crystal aligning agent P was applied onto a glass substrate using a spinner so that the film thickness was 0.1 μm, and dried at 180 ° C. for 1 hour to form a thin film. The thin film was rubbed at a rotational speed of 500 rpm and a stage moving speed of 1 cm / sec using a rubbing machine having a roll around which a nylon cloth was wound.

  4- (4-n-butylcyclohexyl) cyclohexyl acrylate 50 parts by weight, 4- (4-n-propylcyclohexyl) phenyl acrylate 50 parts by weight, photopolymerization initiator IRGACURE907 (manufactured by Ciba Specialty Chemicals), 1 part by weight Then, 100 parts by weight of propylene glycol monomethyl ether acetate as a solvent was mixed to prepare a polymerizable liquid crystal.

This polymerizable liquid crystal was applied on the alignment film subjected to the rubbing treatment by using a spinner and aligned. Next, in order to polymerize and solidify the applied polymerizable liquid crystal, ultraviolet rays were irradiated for 1 minute at 100 mW / cm ² using a high-pressure mercury lamp in a nitrogen atmosphere. The solvent in the polymerizable liquid crystal is volatilized and removed by the temperature rise by ultraviolet irradiation.

  In this way, a retardation plate having a retardation at a wavelength of 633 nm of 317 nm was obtained. This retardation plate was colorless and transparent, and had a uniform slow axis orientation and retardation in the plane.

Examples 1-3
The polyamic acids A-1 to A-3 obtained in Synthesis Examples 1 to 3 were dissolved in a mixed solvent of N-methyl-2-pyrrolidone / butyl cellosolve (60/40) (weight ratio) with the composition shown in Table 2. Then, a solution having a solid content concentration of 2.5% by weight was prepared, and this solution was filtered through a filter having a pore size of 1 μm to prepare liquid crystal alignment agents B-1 to B-3.

The additives in Table 2 are as follows.
E-1: N, N, N ′, N′-tetraglycidyl-4,4′-diaminodi
Phenylmethane

Next, a thin film was formed on the substrate in the same manner as in Reference Example 1 except that the liquid crystal aligning agents B-1 to B-8 were used in place of the liquid crystal aligning agent P. The surface of the thin film was irradiated with non-polarized ultraviolet light 0.1 J / cm ² including an emission line of 254 nm from a direction inclined by 40 degrees from the substrate normal line using a Hg—Xe lamp. Next, a liquid crystal display device was produced in the same manner as in Reference Example 1 except that, when the substrate and the polarizing plate were bonded, instead of the rubbing direction, the projection direction of the optical axis of the ultraviolet rays onto the substrate surface was followed. However, the orientation of the liquid crystal was good. When a voltage was applied under the same conditions as in Reference Example 1, a change in brightness of the liquid crystal display element was observed in response to ON / OFF of the applied voltage in any liquid crystal display element.

  Table 3 shows the determination of the pretilt angle and voltage holding ratio of these liquid crystal display elements.

Examples 4-9
The polyamic acids A-4 to A-8 obtained in Synthesis Examples 4 to 8 were dissolved in a solvent with the composition shown in Table 4 to obtain a solution having a solid content concentration of 2.5% by weight, and this solution was a filter having a pore size of 1 μm. To prepare liquid crystal aligning agents B-4 to B-9.

The additives in Table 4 are as follows.
E-1: N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylphenylmethane E-2: bisphenol A diglycidyl ether

  Next, a liquid crystal display device was produced in the same manner as in Example 1 except that Merck MLC-6608 was used instead of Merck ZLI-1565 as the liquid crystal. In any liquid crystal display element, the liquid crystal exhibited good vertical alignment. When a voltage is applied under the same conditions as in Reference Example 1, a change in brightness of the liquid crystal display element is observed in response to ON / OFF of the applied voltage in any liquid crystal display element, and the liquid crystal orientation during voltage application is It was good.

  Table 5 shows the determination of the pretilt angle and voltage holding ratio of these liquid crystal display elements.

Examples 10-12
In place of the liquid crystal aligning agent P, the liquid crystal aligning agents B-1 to B-3 shown in Table 2 are used. Instead of performing the rubbing treatment, an Hg-Xe lamp is used, and an unpolarized ultraviolet ray containing a 254 nm emission line is 0.1 J. A retardation plate was produced in the same manner as in Reference Example 2 except that / cm 2 was irradiated from a direction inclined by 40 degrees from the substrate normal. The retardation of this retardation plate was 317 nm at a wavelength of 633 nm. The retardation plate was colorless and transparent, and had a uniform slow axis orientation and retardation in the plane.

Comparative Example 1
When a liquid crystal display device was produced in the same manner as in Example 1 except that the liquid crystal aligning agent P was used in place of the liquid crystal aligning agent B-1, no liquid crystal alignment was observed.

Comparative Example 2
A retardation plate was produced in the same manner as in Example 15 except that the liquid crystal aligning agent P was used instead of the liquid crystal aligning agent B-1. The obtained retardation plate was cloudy and had no retardation.

Claims (2)

Tetracarboxylic dianhydride represented by the following formula (I)

(Wherein R ¹ , R ² , R ³ and R ⁴ each represent a hydrogen atom or an organic group having 1 to 30 carbon atoms, provided that at least one of R ¹ , R ² , R ³ and R ⁴ One is an organic group)
A thin film comprising a polyamic acid containing an amic acid structure derived from diamine and a photoalignment agent containing a compound having two or more epoxy groups in the molecule, provided that the thin film is formed on the substrate A method for producing a liquid crystal alignment film, which comprises imparting liquid crystal alignment ability by irradiating non-polarized radiation obliquely with respect to the substrate surface. From the group which the said polyamic acid consists of a C10-30 alkyl group, a C10-30 alicyclic skeleton containing group, and a C2 or more fluorine-containing organic group as tetracarboxylic dianhydride or diamine. The method for producing a liquid crystal alignment film according to claim 1, which is obtained using a compound having at least one selected group.