JP5057052B2 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element. More specifically, the present invention relates to a liquid crystal aligning agent having good image sticking characteristics regardless of the type of electrodes constituting the liquid crystal display element, a liquid crystal alignment film obtained from the liquid crystal aligning agent, and a liquid crystal display element including the film.

Conventionally, a cell of a sandwich structure is formed by forming a nematic liquid crystal layer having positive dielectric anisotropy between two substrates having a liquid crystal alignment film formed on the surface via a transparent conductive film, There is known a TN liquid crystal display element having a TN (Twisted Nematic) type liquid crystal cell in which the major axis of liquid crystal molecules is continuously twisted by 90 degrees from one substrate toward the other substrate.
Further, the addition of a chiral agent achieves a state in which the major axis of the liquid crystal molecules is continuously twisted between the substrates by 180 degrees or more, and an STN (Super Twisted Nematic) type liquid crystal display element utilizing the birefringence effect generated thereby. Is also present. More recently, a homeotropically aligned nematic liquid crystal layer having negative dielectric anisotropy between opposing substrates and a cholesteric liquid crystal layer in which the helical axis is parallel to the substrate normal are formed. A guest-host type reflective liquid crystal display element in which a dye is added to the above has also been developed. The alignment of the liquid crystal in these liquid crystal display elements is usually expressed by a liquid crystal alignment film subjected to a rubbing treatment. Here, as a material for the liquid crystal alignment film constituting the liquid crystal display element, polyimide, polyamide, polyester, and the like are conventionally known. In particular, polyimide is used in many liquid crystal display elements because of its excellent heat resistance, affinity with liquid crystals, mechanical strength, and the like.

Up to now, studies have been made on improving display quality, such as higher definition of liquid crystal display elements, and lowering power consumption. As a result, remarkable progress has been made as a high-performance display element. Liquid crystal display elements having a high retention rate and high reliability have been developed. However, in recent years, in addition to the conventional transmission type, the range of use of liquid crystal display elements such as a reflection type and a semi-transmission type has been expanded. As a result, the required performance for liquid crystal alignment films has become increasingly severe. In particular, demands for image sticking characteristics have become severe in a low-voltage drive type liquid crystal display element aiming at low power consumption, and it cannot be said that the performance of a conventional liquid crystal display element is sufficient. Among liquid crystal alignment films composed of polyamic acid, which is a precursor of conventional polyimide, and imide-based polymers having a structure obtained by dehydrating and cyclizing it, a liquid crystal display element is formed using the liquid crystal alignment film. When prepared, there were many having problems in image sticking characteristics even if the liquid crystal alignment ability was excellent and a sufficient voltage holding ratio was obtained.
Japanese Patent Laid-Open No. 2001-228481

  An object of the present invention is to provide a liquid crystal aligning agent that provides a liquid crystal aligning film that can exhibit a high voltage holding ratio and has good image sticking characteristics.

  Another object of the present invention is to provide a liquid crystal alignment film obtained from the liquid crystal aligning agent and having excellent performance as described above.

  Still another object of the present invention is to provide a liquid crystal display device comprising the liquid crystal alignment film of the present invention.

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

The above objects and advantages of the present invention are, according to the present invention, firstly,
Polyamic acid and / or imidized polymer thereof, and the following formula (1)

  Where X is

Or

R _{1 to} R ₄ are each independently a hydrogen atom or a monovalent aliphatic group, and R _{5 to} R ₇ are each independently a hydrogen atom or a monovalent organic group.
Which is achieved by a liquid crystal aligning agent characterized by containing an epoxy group .

The above objects and advantages of the present invention are secondly,
This is achieved by a liquid crystal alignment film formed from the liquid crystal aligning agent of the present invention.

Third, the above objects and advantages of the present invention are as follows:
This is achieved by a liquid crystal display device including the liquid crystal alignment film of the present invention.

The liquid crystal alignment film formed by the liquid crystal aligning agent of the present invention has excellent image sticking characteristics as compared with conventional alignment films, and is a TN liquid crystal display element, STN liquid crystal display element, reflective liquid crystal display element, and transflective liquid crystal display element. It can be suitably used to construct various liquid crystal display elements.
The liquid crystal display element of the present invention can be effectively used in various devices, and is suitable for display devices such as desk calculators, watches, table clocks, mobile phones, counting display boards, word processors, personal computers, and liquid crystal televisions. Can be used.

  Hereinafter, the present invention will be described in detail.

The liquid crystal aligning agent in the present invention contains a compound represented by the above formula (1) (hereinafter sometimes referred to as a specific compound) and a polyamic acid and / or an imidized polymer thereof, preferably dissolved in an organic solvent. Is done.
[Specific compounds]
The specific compound is represented by the above formula (1). In the formula (1), X is

Or

It is. X is

When this is the case, the formula (1) is represented by the above formula (1) -1. X is

When this is the case, the formula (1) is represented by the above formula (1) -2.

R ₅ , R ₆ and R ₇ are each independently a hydrogen atom or a monovalent organic group. Examples of the monovalent organic group include an alkyl group having 1 to 12 carbon atoms, an alkoxy group, and a phenyl group. These may be substituted. For example, R ₇ may be an alkyl group having an epoxy group.
R _{1 to} R ₄ are each independently a hydrogen atom or a monovalent aliphatic group. Examples of the monovalent aliphatic group include an alkyl group having 1 to 12 carbon atoms, a cyclohexyl group, an alkoxy group having 1 to 12 carbon atoms, a vinyl group, an allyl group, and a glycidyl group.

  As the specific compound, a compound represented by the following formula (1) -1 or (1) -2 is preferable.

Here, the definition of R < ₁ > -R < ₆ > is the same as the said Formula (1).

Here, the definitions of R _{1 to} R ₄ and R ₇ are the same as those in the above formula (1).
A specific compound can be used individually or in combination of 2 or more types.
The specific compound can be synthesized using the following diamine compounds as starting materials.

  Examples of the diamine compound include 2,8-diaminodibenzofuran, 2,8-diaminodibenzothiophene, 2,8-diaminodibenzothiophene, 3,7-diamino-dibenzothiophene, 3,7-diamino-2,8-dimethyl-dibenzo. Thiophene, 9,9-dimethyl-2,7-diaminofluorene, 2,7-diaminofluorene, 9,9-diphenyl-2,7-diaminofluorene, 3,6-diaminocarbazole, 9-methyl-3,6- Examples include diaminocarbazole, 9-ethyl-3,6-diaminocarbazole, 9-phenyl-3,6-diaminocarbazole.

Specific examples of the specific compound include N 2 , N, N ′, N′-tetraglycidyl-2,7-diaminofluorene , N 2 , N, N ′, N′-tetraglycidyl-3,6-diaminocarbazole and the like. be able to.
The specific compound may contain these 1 to 3 substituents.
The blending ratio of these specific compounds is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the polyamic acid or the polyimide polymer.

Polymer The polyamic acid used in the present invention and its imidized polymer, preferably, a repeating unit represented by the following formula (I-1), a repeating unit represented by the following formula (I-2), or these Having both repeating units. Examples thereof include a polyamic acid and / or an imidized polymer having a structure obtained by dehydrating and ring-closing (imidizing) the polyamic acid. The “imidized polymer” in the present invention includes those in which all of the repeating units are imidized and those that are partially imidized. Further, a part of the imide ring may be an isoimide ring.

Here, P ¹ is a tetravalent organic group obtained by removing two anhydride groups from tetracarboxylic dianhydride, and Q ¹ is a divalent organic group obtained by removing two amino groups from the diamine compound.

Here, P ² is a tetravalent organic group obtained by removing two anhydride groups from tetracarboxylic dianhydride, and Q ² is a divalent organic group obtained by removing two amino groups from a diamine compound. .

A preferred polymer in the present invention is a polymer having a repeating unit represented by the above formula (I-1) and a repeating unit represented by the above formula (I-2). Examples of the liquid crystal aligning agent having such a polymer include the following polymers (1) to (3).
(1) A liquid crystal aligning agent containing both a polyamic acid and an imidized polymer.
(2) A liquid crystal aligning agent containing a block copolymer obtained from a prepolymer having an amic acid structure and a prepolymer having an imide structure.
(3) A liquid crystal aligning agent containing an imidized polymer obtained by partially dehydrating and ring-closing polyamic acid.
Of these, (1) and (2) are preferable, and (1) is particularly preferable.

Polyamic acid The polyamic acid used in the present invention is obtained by reacting a tetracarboxylic dianhydride and a diamine.

[Tetracarboxylic dianhydride]
Examples of the tetracarboxylic dianhydride used for the synthesis of the polyamic acid include butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1 , 2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4 -Cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride Anhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3 ′, 4,4′-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxy Pentylacetic acid dianhydride, 3,5,6-tricarboxynorbornane-2-acetic acid 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-di- Oxo-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-furanyl) -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 dianhydride, 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), 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxy Norbornane-2: 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone, represented by the following formula (I ) And fats such as compounds represented by (II) Aliphatic and alicyclic tetracarboxylic dianhydrides;

(Wherein R ¹ and R ³ represent a divalent organic group having an aromatic ring, R ² and R ⁴ represent a hydrogen atom or an alkyl group, and a plurality of R ² and R ⁴ are the same. But it may be different.)
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, 2 , 2 ′, 3,3′-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 ( Anhydrotrimellitate), propylene glycol-bis (anhydrotrimellitate), 1,4-butanediol-bis (anhydrotrimellitate) Retate), 1,6-hexanediol-bis (anhydrotrimellitate), 1,8-octanediol-bis (anhydrotrimellitate), 2,2-bis (4-hydroxyphenyl) propane-bis ( Anhydrotrimellitate) and aromatic tetracarboxylic dianhydrides such as compounds represented by the following formulas (1) to (4). These may be used alone or in combination of two or more.

Of these, butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-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, 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- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] Franc-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), 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1, 2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxynorbornane-2: 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^{2 , 6} ] Undecane-3,5,8,10-tetraone, pyromerit Acid dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 2,2 ′, 3,3 '-Biphenyltetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, represented by the following formulas (5) to (7) among the compounds represented by the above formula (I) Among the compounds represented by formula (II) and the compound represented by formula (II), a compound represented by the following formula (8) is preferable from the viewpoint of exhibiting good liquid crystal orientation. Particularly preferred are 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid 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 -(Tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 3-oxabicyclo [3.2.1] octane-2,4-dione- 6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′-dione), 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride Thing, 3, 5, 6 Carboxy-2-carboxy-norbornane -2: 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^{2, 6]} undecane -3,5,8,10- tetraone And pyromellitic dianhydride and compounds represented by the following formula (5).

[Diamine]
Examples of the diamine 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′-diaminodiphenylsulfone, 3,3′-dimethyl-4,4′-diaminobiphenyl, 4,4′-diaminobenzanilide, 4,4′-diaminodiphenyl ether, 1,5-diaminonaphthalene, 2,2 '-Dimethyl-4,4'-diaminobiphenyl, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 3,3'-ditrifluoromethyl-4,4'-diaminobiphenyl, 5-amino- 1- (4′-aminophenyl) -1,3,3-trimethylindane, 6-amino-1- (4′-aminophenyl) Enyl) -1,3,3-trimethylindane, 3,4'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 2,2-bis [ 4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 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-amino) Phenoxy) benzene, 9,9-bis (4-aminophenyl) -10-hydroanthracene, 2,7-diaminofluorene, 9, 9-dimethyl-2,7-diaminofluorene, 9,9-bis (4-aminophenyl) fluorene, 4,4′-methylene-bis (2-chloroaniline), 2,2 ′, 5,5′-tetra Chloro-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] Hexafluoropropane, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 4,4′-bis [(4-amino-2-trifluoromethyl) phenoxy] -oct Aromatic diamines such as fluoro biphenyl;

1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1 , 4-diaminocyclohexane, isophorone diamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindanylene methylene diamine, tricyclo [6.2.1.0 ^2,7 ] -undecylenedimethyl diamine, 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 Phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, bis (4-aminophenyl) phenylamine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl -3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N, N'-di (4-aminophenyl) -benzidine, and each of the following formulas (III) to (VI) A diamine having two primary amino groups and a nitrogen atom other than the primary amino group in the molecule, such as a compound;

(In the formula, R ⁵ 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.)

(Where X Represents a divalent organic group having a ring structure containing a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine, R ⁶ represents a divalent organic group, and a plurality of Xs are the same or different It may be. )
Monosubstituted phenylenediamine represented by the following formula (V); diaminoorganosiloxane represented by the following formula (VI);

(Wherein R ⁷ represents a divalent organic group selected from —O—, —COO—, —OCO—, —NHCO—, —CONH— and —CO—, and R ⁸ 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.)

(In the formula, R ⁹ represents a hydrocarbon group having 1 to 12 carbon atoms, and a plurality of R ⁹ may be the same or different, p is an integer of 1 to 3, and q is 1 to 20) Is an integer.)
Examples include compounds represented by the following formulas (9) to (13). These diamines can be used alone or in combination of two or more.

(In the formula, y is an integer of 2 to 12, and z is an integer of 1 to 5.)
Of these, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2, 2′-ditrifluoromethyl-4,4′-diaminobiphenyl, 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-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, the above formula (9 ) To (13), 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, 3,6-diaminocarbazole, N- Methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N, N′-di (4-aminophenyl) -benzidine, the above formula (III ) Represented by the following formula (14), among the compounds represented by the above formula (IV), represented by the following formula (15) And dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy-2,5-diamino, among the compounds represented by formula (V) Benzene, dodecanoxy-2,5-diaminobenzene, pentadecanoxy-2,5-diaminobenzene, hexadecanoxy-2,5-diaminobenzene, octadecanoxy-2,5-diaminobenzene, each of the following formulas (16) to (23) The compounds represented are preferred.

[Synthesis 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 the organic solvent used (a) is such that the total amount (b) of the tetracarboxylic dianhydride and the diamine compound is 0.1 to 30% by weight with respect to the total amount (a + b) of the reaction solution. It is preferable that

  The organic solvent can be used in combination with an alcohol, ketone, ester, ether, halogenated hydrocarbon, hydrocarbon, or the like, which is a poor solvent for polyamic acid, as long as the polyamic acid to be produced does not precipitate. 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, diisobutyl ketone, isoamylpropionate, isoamylisobutyrate, diisopentyl ether, etc. In That.

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

Imidized Polymer The imidized polymer used in the present invention is obtained by dehydrating and ring-closing a polyamic acid obtained by reacting tetracarboxylic dianhydride and diamine.

[Tetracarboxylic dianhydride]
Examples of the tetracarboxylic dianhydride used for the synthesis of the imidized polymer include the same compounds as the tetracarboxylic dianhydride used for the synthesis of the polyamic acid described above.
As the tetracarboxylic dianhydride used for the synthesis of the imidized polymer of the present invention, an alicyclic tetracarboxylic dianhydride is preferable. Particularly preferred examples include 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, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) Naphtho [1,2-c] furan-1,3-dione, 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5 '-Dione), 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxy Norbornane-2: 3 : 6-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^{2, 6]} undecane -3,5,8,10- tetraone and the like. Moreover, you may use together and use alicyclic tetracarboxylic dianhydride and another tetracarboxylic dianhydride.

[Diamine]
Examples of the diamine used for the synthesis of the imidized polymer include the same diamine as that used for the synthesis of the polyamic acid described above.
As the diamine used for the synthesis of the imidized polymer of the present invention, a diamine represented by the above formula (V) is preferable. Preferred examples include dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy-2,5-diaminobenzene, dodecanoxy-2,5-diaminobenzene. , Pentadecanoxy-2,5-diaminobenzene, hexadecanoxy-2,5-diaminobenzene, octadecanoxy-2,5-diaminobenzene, and compounds represented by the above formulas (16) to (23).

In the imidized polymer of the present invention, the diamine represented by the above formula (V) and other diamines may be used in combination. Among the other diamines, preferred are p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,2′-dimethyl-4,4 ′. -Diaminobiphenyl, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 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) hexafluoro Propane, 4,4 '-(p-phenylenediisopropylidene) bisaniline, 4,4'-(m-phenylene Isopropylidene) bisaniline, 1,4-cyclohexanediamine, 4,4′-methylenebis (cyclohexylamine), 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, Compounds represented by the above formulas (9) to (13), 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, N, N′- Di (4-aminophenyl) -benzidine, a compound represented by the above formula (14) among the compounds represented by the above formula (III), and a compound represented by the above formula (15) among the compounds represented by the above formula (IV) The compound etc. which are represented by these are mentioned.
In the imidized polymer of the present invention, the diamine represented by the formula (V) is preferably used in an amount of 0.5% by weight or more, particularly preferably 1% by weight or more of the total diamine.

[Synthesis of imidized polymer]
The imidized polymer constituting the liquid crystal aligning agent of the present invention can be obtained by dehydrating and ring-closing the polyamic acid. The polyamic acid is dehydrated and closed by (i) a method of heating the polyamic acid, or (ii) dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring-closing catalyst to this solution, and heating as necessary. By the method.
The reaction temperature in the method of heating the polyamic acid (i) is preferably 50 to 200 ° C, more preferably 60 to 170 ° C. When the reaction temperature is less than 50 ° C., the dehydration ring-closing reaction does not proceed sufficiently, and when the reaction temperature exceeds 200 ° C., the molecular weight of the imidized polymer obtained may decrease.

  On the other hand, in the method (ii) of adding a dehydrating agent and a dehydrating ring-closing catalyst to the polyamic acid solution, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride is used as the dehydrating agent. Can do. The amount of the dehydrating agent used is preferably 0.01 to 20 mol with respect to 1 mol of the polyamic acid repeating unit. Moreover, as a dehydration ring closure catalyst, tertiary amines, such as a pyridine, a collidine, a lutidine, a triethylamine, can be used, for example. However, it is not limited to these. The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. Examples of the same solvent as the organic solvent used for the dehydration ring-closing reaction include the same solvents as those exemplified as those used for the synthesis of the polyamic acid. And the reaction temperature of dehydration ring closure reaction becomes like this. Preferably it is 0-180 degreeC, More preferably, it is 10-150 degreeC. In addition, the imidized polymer can be purified by performing the same operation as the polyamic acid purification method on the reaction solution thus obtained.

  The imidized polymer used in the present invention may be partially dehydrated and closed and have a low imidization rate. The imidation ratio in the imidized polymer used in the present invention is preferably 80% or more, more preferably 85% or more. Here, the “imidation ratio” is the percentage of the number of repeating units that form an imide ring with respect to the total number of repeating units in the polymer. At this time, a part of the imide ring may be an isoimide ring. The imidization rate can be determined by the following method.

[Method for measuring imidization rate of imidized polymer]
The imidized polymer is dried at room temperature under reduced pressure, then dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR is measured at room temperature using tetramethylsilane as a reference substance, and obtained by the formula represented by the following formula (ii). Can do.
Imidation ratio (%) = (1-A ¹ / A ² × α) × 100 ------ (ii)
A ¹ : NH group proton-derived peak area (10 ppm)
A ² : Peak area derived from other protons α: Number ratio of other protons to one proton of NH group in polymer precursor (polyamic acid)

Terminal-modified polymer The polyamic acid and imidized polymer may be of a terminal-modified type whose molecular weight is adjusted. Such a terminal-modified type can be synthesized by adding an acid monoanhydride, a monoamine compound, a monoisocyanate compound or the like to the reaction system when synthesizing the polyamic acid. Here, examples of the acid monoanhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, N-decylsuccinic anhydride, N-dodecylsuccinic anhydride, and N-tetradecylsuccinic anhydride. N-hexadecyl succinic acid anhydride and the like. Examples of the monoamine compound include aniline, cyclohexylamine, N-butylamine, N-pentylamine, N-hexylamine, N-heptylamine, N-octylamine, N-nonylamine, N-decylamine, and N-undecyl. Amine, N-dodecylamine, N-tridecylamine, N-tetradecylamine, N-pentadecylamine, N-hexadecylamine, N-heptadecylamine, N-octadecylamine, N-eicosylamine, etc. be able to. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

[Solution viscosity]
The polymer used in the aligning agent of the present invention preferably has a viscosity of 20 to 800 mPa · s, and preferably has a viscosity of 30 to 500 mPa · s when a 10% solution is obtained. Is more preferable.
The solution viscosity (mPa · s) of the polymer was measured at 25 ° C. using an E-type rotational viscometer for a solution diluted to a predetermined solid content concentration using a predetermined solvent.

Liquid crystal aligning agent The liquid crystal aligning agent of this invention is comprised by the said (A) polymer and (B) epoxy-containing compound being normally dissolved and contained in the organic solvent.
The temperature at which the liquid crystal aligning agent of the present invention is prepared is preferably 0 ° C to 200 ° C, more preferably 20 ° C to 60 ° C.
As an organic solvent which comprises the liquid crystal aligning agent of this invention, the same solvent as the solvent illustrated as what is used for the synthesis reaction of a polyamic acid can be mentioned. 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 liquid crystal aligning agent of the present invention is selected in consideration of viscosity, volatility and the like. Preferably it is the range of 1-10 weight%. That is, the liquid crystal aligning agent of 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 When the solid content concentration exceeds 10% by weight, it is difficult to obtain a good liquid crystal alignment film because the film thickness is excessive. The viscosity of the aligning agent increases, resulting in poor coating properties.
The particularly preferable solid content concentration range varies depending on the method used when the liquid crystal aligning agent is applied to the substrate. For example, when the spinner method is used, the range of 1.5 to 4.5% by weight is particularly preferable. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by weight, and thereby the solution viscosity is in the range of 12 to 50 mPa · s. In the case of the ink jet method, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by weight, and thereby the solution viscosity is in the range of 3 to 15 mPa · s.

  Particularly preferable organic solvents used in the liquid crystal alignment agent of the present invention include, for example, N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, Hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-N- Propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-N-butyl ether (butyl cellosolve), 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, diisobutyl ketone (DIBK), isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, etc. Can be mentioned. These can be used alone or in admixture of two or more.

The liquid crystal aligning agent of the present invention may contain an epoxy group-containing compound from the viewpoint of improving the adhesion to the substrate surface. Examples of the epoxy group-containing compound include 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, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N, N ′, N′-tetraglycidyl-m-xylenediamine, 1, 1,3-bis (N, N-diglycidyl aminomethyl) cyclohexane, N, N, N ', N'- tetraglycidyl-4,4'-diaminodiphenylmethane, N, N-diglycidyl - benzylamine, N, N-diglycidyl - it may be mentioned as being preferred and aminomethyl cyclohexane. The blending ratio of these and the epoxy group-containing compound is preferably 40 parts by weight or less, more preferably 30 parts by weight or less with respect to 100 parts by weight of the polymer.

Liquid crystal display element The liquid crystal display element of this invention can be manufactured, for example with the following method.

(1) The liquid crystal aligning agent of the present invention is preferably applied to one surface of a substrate provided with a patterned transparent conductive film, preferably by a printing method or the like, and then the coated surface is heated by heating the coated surface. Form. Here, as the substrate, for example, glass such as float glass or soda glass; a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, alicyclic polyolefin, or the like can be used. As a transparent conductive film provided on one surface of the substrate, a NESA film (registered trademark of PPG, USA) made of tin oxide (SNO ₂ ), an ITO film made of indium oxide-tin oxide (IN ₂ O ₃ -SNO ₂ ), etc. Can be used. For patterning these transparent conductive films, a photo-etching method or a method using a mask in advance is used. When applying the liquid crystal aligning agent, in order to further improve the adhesion between the substrate surface and the transparent conductive film and the coating film, a functional silane-containing compound, a functional titanium-containing compound, or the like is previously applied to the surface of the substrate. You can also After applying the liquid crystal aligning agent, preheating (pre-baking) is preferably performed for the purpose of preventing dripping of the applied aligning agent. The pre-baking temperature is preferably 30 to 300 ° C, more preferably 40 to 200 ° C, and particularly preferably 50 to 150 ° C. Thereafter, a baking (post-baking) step is performed for the purpose of completely removing the solvent and heat imidizing the polyamic acid. The firing (post-bake) temperature is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. In this way, the liquid crystal aligning agent of the present invention containing a polyamic acid forms a coating film that becomes a liquid crystal aligning film by removing the organic solvent after coating, and further proceeds with dehydration ring closure by further heating. It can also be set as the imidized coating film. The film thickness of the formed coating film is preferably 0.001-1 μm, more preferably 0.005-0.5 μm.

(2) A rubbing process is performed in which the formed coating film surface is rubbed in a certain direction with a roll wound with a cloth made of a fiber such as nylon, rayon, or cotton. Thereby, the orientation ability of a liquid crystal molecule is provided to a coating film, and it becomes a liquid crystal aligning film.
Further, by partially irradiating the liquid crystal alignment film formed of the liquid crystal alignment agent of the present invention with ultraviolet rays as disclosed in, for example, JP-A-6-222366 and JP-A-6-281937. A resist film is partially formed on the surface of the liquid crystal alignment film that has been subjected to a treatment for changing the pretilt angle or a rubbing treatment as disclosed in JP-A-5-107544, which is different from the previous rubbing treatment. The visibility characteristics of the liquid crystal display element can be improved by removing the resist film after performing the rubbing treatment in the direction and changing the liquid crystal alignment ability of the liquid crystal alignment film.

(3) Two substrates on which the liquid crystal alignment film is formed as described above are manufactured, and the two substrates are separated by a gap (cell gap) so that the rubbing directions in the respective liquid crystal alignment films are orthogonal or antiparallel. ), And the periphery of the two substrates are bonded together using a sealant, and liquid crystal is injected and filled in the cell gap defined by the substrate surface and the sealant, and the injection hole is sealed. A liquid crystal cell is constructed. A polarizing plate is disposed on the outer surface of the liquid crystal cell, that is, on the other surface side of each substrate constituting the liquid crystal cell, and the polarization direction thereof coincides with or is orthogonal to the rubbing direction of the liquid crystal alignment film formed on one surface of the substrate. A liquid crystal display element is obtained by pasting together.
Here, as the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used.

Examples of the liquid crystal include nematic liquid crystal and smectic liquid crystal. Among them, nematic liquid crystal is preferable. For example, Schiff base liquid crystal, azoxy liquid crystal, biphenyl liquid crystal, phenyl cyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal. Liquid crystals, biphenylcyclohexane liquid crystals, pyrimidine liquid crystals, dioxane liquid crystals, bicyclooctane liquid crystals, cubane liquid crystals, and the like can be used. Further, for these liquid crystals, for example, cholesteric liquid crystals such as cholestyl chloride, cholesteryl nonate, cholesteryl carbonate, and chiral agents such as those sold under the trade names “C-15” and “CB-15” (manufactured by Merck). Etc. can also be used. Furthermore, a ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate can also be used.
Further, as a polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing film or an H film in which a polarizing film called an H film that absorbs iodine while sandwiching and stretching polyvinyl alcohol is sandwiched between cellulose acetate protective films. The polarizing plate which consists of itself can be mentioned.

  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 imidization rate and voltage holding rate of the imidized polymer in Examples and Comparative Examples were evaluated by the following methods.

[Method for measuring imidization rate of imidized polymer]
The imidized polymer was dried at room temperature under reduced pressure, then dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference substance, and determined by the formula shown by the following formula (ii). .
Imidation ratio (%) = (1-A ¹ / A ² × α) × 100 ------ (ii)
A ¹ : NH group proton-derived peak area (10 ppm)
A ² : Peak area derived from other protons α: Number ratio of other protons to one proton of NH group in polymer precursor (polyamic acid)

[Solution viscosity]
The solution viscosity (mPa · s) of the polymer was measured at 25 ° C. using an E-type rotational viscometer for a solution diluted to a predetermined solid content concentration using a predetermined solvent.

[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.

[Burn-in test]
A cell having an ITO electrode as shown in FIG. 1 was produced. A DC voltage of 6.0 V was applied to electrode A and a DC voltage of 0.5 V was applied to electrode B at room temperature for 72 hours. After releasing the stress, a DC voltage of 0.1 to 5.0 V was applied to the electrodes A and B in increments of 0.1 V. The image sticking characteristics were determined based on the luminance difference between the electrodes A and B at each voltage. When the luminance difference was large, it was judged that the image sticking characteristic was bad.

Synthesis example 1
2,3,5-tricarboxycyclopentyl acetic acid dianhydride 112 g (0.50 mol) and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro) as tetracarboxylic dianhydride -2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione 157 g (0.50 mol), p-phenylenediamine 96 g (0.89 mol) as the diamine compound, bis 25 g (0.10 mol) of aminopropyltetramethyldisiloxane and 13 g (0.020 mol) of 3,6-bis (4-aminobenzoyloxy) cholestane, 8.1 g (0.030 mol) of N-octadecylamine as a monoamine ) Was dissolved in 960 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours. A small amount of the obtained polyamic acid solution was taken, NMP was added, and the viscosity was measured with a solution having a solid content concentration of 10%. As a result, it was 60 mPa · S. Next, 2,700 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 396 g of pyridine and 409 g of acetic anhydride were added, and dehydration ring closure was performed at 110 ° C. for 4 hours. After the imidization reaction, the solvent in the system was replaced with a new γ-butyrolactone (the pyridine and acetic anhydride used for the imidization reaction were removed from the system in this operation), and the solid content concentration was 15 wt%. About 2,000 g of an imidized polymer solution (referred to as “polyimide (A-1)”) having a solution viscosity of 16 mPa · S at a concentration of 6.0% (γ-butyrolactone solution) and an imidization ratio of about 95%. Obtained.

Synthesis example 2
196 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 212 g (1 of 2,2′-dimethyl-4,4′-diaminobiphenyl as diamine compound) 0.0 mol) was dissolved in N-methyl-2-pyrrolidone (370 g) and γ-butyrolactone (3,300 g) and reacted at 40 ° C. for 3 hours, and the solution viscosity was 160 mPa · S polyamic acid (this was referred to as “polyamic acid (B- 1) ") About 3,700 g of solution was obtained.

Synthesis example 3
2,7-Diaminofluorene (10 g, 0.051 mol), epichlorohydrin (3.8 g, 0.041 mol), tetrahydrofuran (100 ml) and water (4.5 ml) were mixed, and the mixture was heated and stirred at 80 ° C. for 4 hours. After the reaction temperature was lowered to 60 ° C., 10 g of 50% NaOH aqueous solution was added dropwise. After heating and stirring for 4 hours, unreacted epichlorohydrin was distilled off under reduced pressure. The residue was separated and washed with toluene / water, and the solvent was distilled off to obtain 13.9 g of the desired epoxy compound (C-1).

Synthesis example 4
In Synthesis Example 3, 12.9 g of the target epoxy compound (C-2) was obtained by using 10.06 g (0.051 mol) of 3,6-diaminocarbazole instead of 2,7-diaminofluorene.

Example 1
The polyimide (A-1) obtained in Synthesis Example 1 and the polyamic acid (B-1) obtained in Synthesis Example 3 were mixed with γ-butyrolactone so that polyimide: polyamic acid = 20: 80 (weight ratio). / N-methyl-2-pyrrolidone / butyl cellosolve mixed solvent (weight ratio 71/17/12). The epoxy body (C-1) was dissolved in this solution so that it might be 15 weight part with respect to 100 weight part of polymers, and it was set as the solution of solid content concentration 3.5 weight%. After sufficient stirring, the solution was filtered using a filter having a pore size of 1 μm to prepare the liquid crystal aligning agent of the present invention. The liquid crystal aligning agent was applied onto a transparent conductive film made of an ITO film provided on one surface of a glass substrate having a thickness of 1 mm using a spinner (rotation speed: 2500 rpm, application time: 1 minute), and 200 A film having a dry film thickness of 0.08 μm was formed by drying at 0 ° C. for 1 hour. A rubbing machine having a roll in which a rayon cloth was wound around this film was subjected to a rubbing treatment at a roll rotation speed of 400 rpm, a stage moving speed of 3 cm / second, and a hair foot pushing length of 0.4 mm. The liquid crystal alignment film-coated substrate was subjected to ultrasonic cleaning for 1 minute in ultrapure water and dried in a 100 ° C. clean oven for 10 minutes. Next, after applying an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm to the outer edges of the pair of transparent electrodes / transparent electrode substrates having the liquid crystal alignment film of the liquid crystal alignment film coated substrate, the liquid crystal alignment film The adhesive was cured by overlapping and pressing so that the surfaces were opposed. Next, a nematic liquid crystal (MLC-6221 manufactured by Merck & Co., Inc.) was filled between the substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an acrylic photo-curing adhesive to produce a liquid crystal display element. The voltage holding ratio of the obtained liquid crystal display element was evaluated. The liquid crystal aligning agent obtained in the present invention showed a high voltage holding ratio of 99% or more. Moreover, when the image sticking test was conducted, good results were shown.

Example 2
It carried out similarly to Example 1 except having used the epoxy body (C-2) instead of the epoxy body (C-1). The results are shown in Table 1.

Comparative Example 1
The same operation as in Example 1 was performed except that a liquid crystal display element was produced without using an epoxy body.
Then, voltage holding ratio and image sticking characteristics were evaluated. The results are shown in Table 1.

Explanatory drawing of the cell used for the burn-in test.

Claims (6)

Polyamic acid and / or imidized polymer thereof, and the following formula (1)

Where X is

Or

R _{1 to} R ₄ are each independently a hydrogen atom or a monovalent aliphatic group, and R _{5 to} R ₇ are each independently a hydrogen atom or a monovalent organic group.
A liquid crystal aligning agent comprising: a compound represented by the formula: wherein the compound has an epoxy group . The compound represented by the above formula (1) is R in the above formula (1). ₁ ~ R ₄ The liquid crystal aligning agent of Claim 1 which is a reaction product of the diamine compound and epichlorohydrin whose are hydrogen atoms. The compound represented by the above formula (1) is represented by the following formula (1) -1.

_Here, definitions of R 1 to R ₆ are the same as the equation (1),
The liquid crystal aligning agent of Claim 1 or 2 represented by these. The compound represented by the above formula (1) is represented by the following formula (1) -2.

Here, the definitions of R _{1 to} R ₄ and R ₇ are the same as those in the above formula (1).
The liquid crystal aligning agent of Claim 1 or 2 represented by these. The liquid crystal aligning film formed from the liquid crystal aligning agent in any one of Claims 1-4 . A liquid crystal display device comprising the liquid crystal alignment film according to claim 5 .

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