JPH10104633A - Liquid crystal alignment agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystal alignment agent which allows lowtemp. baking, has good orientability of liquid crystals and is capable of forming a liquid crystal oriented film of the short residual image erasure time at the time of impression of a liquid crystal cell by incorporating an imidized polymer which has a specific repeating unit and has an intrinsic viscosity within a spe cific range. SOLUTION: This liquid crystal alignment agent contains the imidized polymer which has the repeating unit expressed by the formula and of which the intrinsic viscosity [ηinh] (where, concn. 0.5g/dlr measured at 30 deg.C in an N-methyl pyrrolidone solvent) is 0.05 to 10dl/g. In the formula, R<1> is a quadrivalent org. group and R<2> is a bivalent org. group having a nitrogen atom. The liquid crystal display element having the liquid crystal oriented film formed by using the liquid crystal orienting agent is usable adequately for TN type and STN type liquid crystal display elements and is also made usable adequately for SH type, IPS type, ferroelectric and antiferroelectric liquid crystal display element, etc., by selecting the liquid crystal to be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal aligning agent which can be fired at a low temperature and can form a liquid crystal alignment film having a short afterimage erasing time when a voltage is applied to the liquid crystal cell when the liquid crystal cell is assembled into the liquid crystal cell.

[0002]

2. Description of the Related Art Conventionally, a nematic liquid crystal having a positive dielectric anisotropy has a sandwich structure with a substrate having a transparent electrode having a liquid crystal alignment film made of polyimide or the like, and the major axis of the liquid crystal molecules is continuous at 90 degrees between the substrates. 2. Description of the Related Art A liquid crystal display element (TN liquid crystal display element) having a TN (Twisted Nematic) liquid crystal cell which is twisted likewise is known. This TN
The alignment of the liquid crystal in the liquid crystal display device is formed by a liquid crystal alignment film subjected to a rubbing treatment. Recently, an STN (Super Twisted Nematic) type liquid crystal display device, which is a liquid crystal display device excellent in contrast and viewing angle dependence, has been developed. The STN-type liquid crystal display device uses a nematic liquid crystal as a liquid crystal and a chiral agent which is an optically active substance blended. The birefringence effect caused by continuously twisting the major axis of the liquid crystal molecule between the substrates by 180 degrees or more is used. To use. The alignment of the liquid crystal in the TN-type and STN-type liquid crystal display elements is usually formed by a rubbed liquid crystal alignment film, but ionic charges are adsorbed on the liquid crystal alignment film surface when a voltage is applied, resulting in an afterimage. Therefore, there is a problem that a sufficient contrast cannot be obtained. At this time, the time until the afterimage is erased (hereinafter, also referred to as “afterimage erasing time”) varies depending on the use and the like, but is preferably about 5 seconds or less when a DC voltage of 10 V is applied for 1 hour.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal alignment film which can be fired at a low temperature, has good liquid crystal alignment properties, and can form a liquid crystal alignment film having a short afterimage erasing time when a liquid crystal cell is applied. To provide an agent.

[0004]

An object of the present invention is to provide a polymer having a repeating unit represented by the following formula (A) and an intrinsic viscosity [ηinh] (provided that the concentration in an N-methylpyrrolidone solvent is 0.5 g / dl, measured at 30 ° C. The same applies hereinafter.)
It can be achieved by a liquid crystal aligning agent characterized by containing an imidized polymer of from 10 to 10 dl / g.

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[0005] (In the formula, R ¹ is a tetravalent organic group, R ²
Is a divalent organic group having a nitrogen atom. )

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail. In the liquid crystal aligning agent of the present invention, the repeating unit represented by the formula (A) (hereinafter, also referred to as “specific repeating unit”) is usually 5 to 100 mol%, preferably 50 mol%, based on the imidized polymer. １００100 mol%. If the proportion of the specific repeating unit is less than 5 mol%, the desired afterimage characteristics may not be exhibited. The liquid crystal aligning agent of the present invention includes (1) an imidized polymer having a structure having only a specific repeating unit, (2) a random or block copolymer having a specific repeating unit and another repeating unit, and (3) a specific or repeating unit. It is composed of a mixture of an imidized polymer having a repeating unit and an imidized polymer having no specific repeating unit, and the imidized polymer is obtained by reacting a tetracarboxylic dianhydride with a diamine compound. The polyamic acid is synthesized by dehydration and ring closure.

[Tetracarboxylic dianhydride] Examples of the tetracarboxylic dianhydride used in the synthesis of the above polyamic acid include 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,2- Dimethyl-1,2,2
3,4-cyclobutanetetracarboxylic dianhydride, 1,
3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4
-Cyclobutanetetracarboxylic dianhydride, 1,2,2
3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetra Carboxylic dianhydride, 3,3 ′,
4,4'-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 3,5,6-tricarboxynorbornane-2
-Acetic dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 1,3,3a, 4,5,9
b-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-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, 4,5,9
b-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, the following formulas (I) to (II)
An alicyclic tetracarboxylic dianhydride such as a compound represented by the formula:

[0008]

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(Wherein, R ³ and R ⁵ each represent a divalent organic group having an aromatic ring, R ⁴ and R ^{6 each} represent a hydrogen atom or an alkyl group, and a plurality of R ⁴ and R ⁶ each represent They may be the same or different.)

Aliphatic tetracarboxylic dianhydrides such as butanetetracarboxylic dianhydride; pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3' , 4,4'-biphenylsulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic 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 acid Dianhydride, 4,4'-bis (3,
4-dicarboxyphenoxy) diphenylsulfide dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) 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'-diphenylether dianhydride, bis (triphenylphthalic acid)-
4,4′-diphenylmethane dianhydride, ethylene glycol-bis (anhydrotrimellitate), propylene glycol-bis (anhydrotrimellitate), 1,
4-butanediol-bis (anhydrotrimellitate), 1,6-hexanediol-bis (anhydrotrimellitate), 1,8-octanediol-bis (anhydrotrimellitate), 2,2- Aromatic tetracarboxylic dianhydrides such as bis (4-hydroxyphenyl) propane-bis (anhydrotrimellitate) and compounds represented by the following formulas (1) to (4) can be given. These are used alone or in combination of two or more.

[0011]

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Of these, 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] 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 acid Anhydrides and compounds represented by the following formula (5) among the compounds represented by the above formula (I)
Alicyclic tetracarboxylic dianhydride such as a compound represented by the following formula (8) among the compounds represented by the formulas (II) to (7) and Are preferred from the viewpoint of allowing the expression of 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4
-Cyclobutanetetracarboxylic dianhydride, 2,3,5
-Tricarboxycyclopentyl acetic dianhydride, 1,
3,3a, 4,5,9b-Hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3
a, 4,5,9b-Hexahydro-8-methyl-5-
(Tetrahydro-2,5-dioxo-3-furanyl)-
Examples include naphtho [1,2-c] furan-1,3-dione and a compound represented by the following formula (5).

[0013]

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<Diamine Compound> The diamine compound used in the synthesis of the above polyamic acid has two 1
A diamine compound having a primary amino group and a nitrogen atom other than the primary amino group (hereinafter, also referred to as “specific diamine compound”). In particular, diamine compounds having a ring structure containing a nitrogen atom, such as a pyridine ring, a pyrimidine ring, a triazine ring, a piperidine ring, and a piperazine ring, are preferable. For example, 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, , 4-bis (3-aminopropyl) piperazine, 2,4-diamino-6-isopropoxy-1,3,5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, , 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-diaminopurine,
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, Examples thereof include bis (4-aminophenyl) phenylamine and compounds represented by the following formulas (III) to (VI).

[0015]

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(Wherein, R ⁷ represents a monovalent organic group having a ring structure containing a nitrogen atom selected from a pyridine ring, a pyrimidine ring, a triazine ring, a piperidine ring and a piperazine ring, and X represents a single bond or It represents a divalent organic group.)

[0017]

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(Wherein, R ⁸ represents a divalent organic group having a ring structure containing a nitrogen atom selected from a pyridine ring, a pyrimidine ring, a triazine ring, a piperidine ring and a piperazine ring, and X represents a single bond or It represents a divalent organic group, and a plurality of Xs may be the same or different.)

Of these, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine and the compound of the above formula (II
Among the compounds represented by the formula (I), the compound represented by the following formula (9) and the compound represented by the following formula (IV) among the compounds represented by the above formula (IV) have particularly good liquid crystal alignment properties. Is preferred. These may be used alone or 2
It can be used in combination of more than one kind.

[0020]

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In the present invention, another diamine compound can be used in combination as a component constituting a repeating unit other than the specific repeating unit. Such other diamine compounds include, for example, 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, 3,3-dimethyl-4,4'-diaminobiphenyl, 5-amino-1- (4'-aminophenyl) -1,3,3-trimethylindane, 6-amino-1- (4'-aminophenyl) -1,3,3 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-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′-tetrachloro-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 Aromatic diamines such as' -bis [(4-amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl;

1,1-meta-xylylenediamine, 1,3
-Propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1,4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclo Pentadienylenediamine, hexahydro-4,7-methanoindanylene dimethylenediamine, tricyclo [6,2,1,02.7]-
Aliphatic and cycloaliphatic diamines such as undecylenedimethyldiamine, 4,4'-methylenebis (cyclohexylamine);

A monosubstituted phenylenediamine represented by the following formula (V); a diaminoorganosiloxane represented by the following formula (VI):

[0024]

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(Wherein R ⁹ is —O—, —COO—,
OCO-, -NHCO-, -CONH- and -CO-
And R ¹⁰ represents a monovalent organic group having a steroid skeleton or a trifluoromethyl group. )

[0026]

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(In the formula, R ¹¹ represents a hydrocarbon group having 1 to 12 carbon atoms, a plurality of R ¹¹ may be the same or different, p is an integer of 1 to 3, and q is 1-2
It is an integer of 0. )

Examples include compounds represented by the following formulas (11) to (15). These diamine compounds can be used alone or in combination of two or more.

[0029]

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(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, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 2,2-
Bis [4- (4-aminophenoxy) phenyl] propane, 9,9-bis (4-aminophenyl) fluorene, 4,4 '-(p-phenylenediisopropylidene)
Bisaniline, 1,4-bis (4-aminophenoxy)
Benzene, 4,4′-bis (4-aminophenoxy) biphenyl, the compounds represented by the above formulas (11) to (15), and the compound represented by the following formula (1) among the compounds represented by the above formula (V)
Compounds represented by 6) to (20) are preferred. These can be used alone or in combination of two or more. These diamines may be used as they are, or may be used after being reduced again.

[0032]

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In the liquid crystal aligning agent of the present invention, the most preferred combination of tetracarboxylic dianhydride and diamine compound is 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-dianhydride. 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, 1,3,3
a, 4,5,9b-Hexahydro-8-methyl-5-
(Tetrahydro-2,5-dioxo-3-furanyl)-
Alicyclic tetracarboxylic dianhydride, 2,6-diaminopyridine, 3,4 selected from naphtho [1,2-c] furan-1,3-dione and the compound represented by the above formula (5)
-Diaminopyridine, 2,4-diaminopyrimidine, 3,
6-diaminoacridine and the above formulas (9) to (10)
And a specific diamine compound selected from the compounds represented by the following formulas and p-phenylenediamine, 4,4′-diaminodiphenylmethane, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 2,2-bis [4- (4- Aminophenoxy) phenyl] propane, 9,9-bis (4-aminophenyl) fluorene, 4,4 ′-(p-phenylenediisopropylidene) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4'-bis (4-aminophenoxy) biphenyl and the above formula (1
Examples include combinations of other aromatic diamine compounds selected from the compounds represented by 1) to (20). The use ratio of the specific diamine compound in the combination is preferably 5 to 80 mol% based on all the diamine compounds.

[Synthesis of Polyamic Acid] The ratio of the tetracarboxylic dianhydride and the diamine compound to be used in the synthesis reaction of the polyamic acid is as follows.
The ratio of the acid anhydride group of the tetracarboxylic dianhydride to 0.2 to 2 equivalents per 1 equivalent of the primary amino group is preferable,
The ratio is more preferably 0.3 to 1.2 equivalents.
The synthesis reaction of the polyamic acid is usually performed in an organic solvent at 0 to
At a reaction temperature of 150 ° C, preferably 0-100 ° C,
Performed over 8 hours. The organic solvent is not particularly limited as long as it can dissolve the reactant generated in the reaction. For example, N-methyl-2-pyrrolidone, N, N
Aprotic polar solvents such as dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide; phenolic solvents such as m-cresol, xylenol, phenol and halogenated phenol Solvents can be mentioned. The amount of organic solvent used is
Usually, the total amount of the tetracarboxylic dianhydride and the diamine compound is 0.1 to 30% by weight based on the total amount of the reaction solution.
It is preferable that In addition, in the above organic solvent, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, etc., which are poor solvents for the polyamic acid, are used in combination within a range where the generated polyamic acid does not precipitate. be able to. Specific examples of such poor solvents include, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol,
Tetrahydrofurfuryl alcohol, ethylene glycol, propylene glycol, 1,4-butanediol,
Triethylene glycol, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate, diethyl malonate, diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol monophenyl ether, ethylene glycol methyl phenyl Ether, ethylene glycol ethyl phenyl ether, 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, ethylene glycol methyl ether acetate, ethylene glycol Lumpur ethyl ether acetate, 4
-Hydroxy-4-methyl-2-pentanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, 2- Methyl hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate,
Methyl 3-ethoxypropionate, 3-methyl-3-methoxybutanol, 3-ethyl-3-methoxybutanol, 2-methyl-2-methoxybutanol, 2-ethyl-2-methoxybutanol, 3-methyl-3-ethoxy Butanol, 3-ethyl-3-ethoxybutanol, 2
-Methyl-2-methoxybutanol, 2-ethyl-2-
Ethoxybutanol, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene,
Examples include toluene and xylene. These may be used alone or in combination of two or more.

As described above, a reaction solution obtained by dissolving the polyamic acid is obtained. Pouring the reaction solution into a poor solvent to precipitate the polyamic acid, dissolving the deposited polyamic acid in the organic solvent again, and then performing the step of depositing with the poor solvent once or several times can purify the polyamic acid. it can.

For the purpose of controlling the molecular weight of the imidized polymer obtained from the polyamic acid, improving coatability on a substrate, etc., the terminal modification obtained by adding an acid monoanhydride or a monoamine compound during the synthesis of the polyamic acid. Polyamic acids of the type can also be used as precursors of the imidized polymer. Examples of the acid monoanhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride,
Examples thereof include n-tetradecylsuccinic anhydride, n-hexadecylsuccinic anhydride, and n-octadecylsuccinic anhydride. Examples of the monoamine include aniline, cyclohexylamine, n
-Butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-
Nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-
Examples thereof include tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, and n-eicosylamine.

[Imidated Polymer] The imidized polymer constituting the liquid crystal aligning agent of the present invention can be prepared by dehydrating and ring-closing the above polyamic acid. The dehydration and ring closure of the polyamic acid can be performed by (i) heating the polyamic acid or (ii) dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and an imidization catalyst to the solution, and heating as necessary. It is done by doing. In the above reaction (i), the reaction temperature is usually from 60 to 250.
° C, preferably 100 to 170 ° C. Reaction temperature 6
When the reaction temperature is lower than 0 ° C, the dehydration ring-closing reaction does not sufficiently proceed, and when the reaction temperature exceeds 250 ° C, the molecular weight of the obtained imidized polymer may decrease. In the above reaction (ii), the reaction temperature is usually 0 to 180 ° C, preferably 60 to 150 ° C.
° C. As the dehydrating agent, for example, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. Further, as the imidation catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, and triethylamine can be used, but are not limited thereto. The amount of the dehydrating agent used is preferably 1.5 to 20 mol per 1 mol of the repeating unit of the polyamic acid. The amount of the imidization catalyst used is preferably 0.5 to 10 mol per 1 mol of the dehydrating agent used. In addition, as the imidized polymer constituting the liquid crystal aligning agent of the present invention, a polymer having a amic acid structure in which a part of the polymer is not dehydrated and ring-closed may be used. In that case,
As described above, the ratio of the specific repeating unit to the imidized polymer is usually 5 mol% or more, preferably 50 mol% or more. The imidization ratio of the imidized polymer used in the present invention is preferably 80% or more.

[Liquid Crystal Alignment Agent] The liquid crystal alignment agent of the present invention is obtained by dissolving the above imidized polymer in an organic solvent. The content ratio of the imidized polymer in the liquid crystal aligning agent of the present invention is selected in consideration of viscosity, volatility and the like, but is preferably in the range of 0.1 to 20% by weight, more preferably 1 to 10% by weight. It is said. That is, a liquid crystal aligning agent comprising an imidized polymer solution is applied to the substrate surface by a printing method, a spin coating method, etc., and then dried to form a film serving as a liquid crystal alignment film. When the content of the polymerized polymer is less than 0.1% by weight,
In some cases, a good liquid crystal alignment film cannot be obtained because the thickness of the coating film is too small, and when it exceeds 20% by weight, the thickness of the coating film becomes too large to form a good liquid crystal alignment film. In some cases, it is difficult to obtain, and the viscosity of the liquid crystal aligning agent may increase, resulting in poor coating characteristics. The organic solvent for dissolving the imidized polymer is not particularly limited as long as it can dissolve the imidized polymer, and examples thereof include solvents exemplified as those used in the synthesis reaction of polyamic acid and the dehydration ring closure reaction. Can be mentioned. In addition, the poor solvents exemplified as those which can be used together in the synthesis reaction of the polyamic acid can be appropriately selected and used in combination.

The liquid crystal aligning agent of the present invention may contain a functional silane-containing compound or an epoxy compound from the viewpoint of improving the adhesion between the imidized polymer and the surface of the substrate to be coated. Examples of the functional silane-containing compound 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-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N -Triethoxysilylpropyltriethylenetriamine, N
-Trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-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-aminopropyltriacetate Methoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, and the like. Can be. Examples of the epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, and 1,6.
-Hexanediol diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether,
1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N, N ', N'-tetraglycidyl-m
-Xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, bisphenol A
Type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, tetraglycidyldiaminodiphenylmethane, triglycidylaminophenol, tetraglycidylmethaxylylenediamine, diglycidyltribromoaniline, and the like.

[Liquid crystal display device] A liquid crystal display device obtained by using the liquid crystal aligning agent of the present invention can be produced, for example, by the following method. (1) The liquid crystal aligning agent of the present invention is applied to the transparent conductive film side of the substrate on which the patterned transparent conductive film is provided, for example, by a method such as a roll coater method, a spinner method, or a printing method. A film is formed by heating. Here, as the substrate, for example, float glass,
A transparent substrate made of glass such as soda glass, a plastic film of polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, or the like can be used. As the transparent conductive film provided on one surface of the substrate, NE made of SnO ₂ is used.
An SA film, an ITO film made of In ₂ O ₃ —SnO ₂ , or the like can be used. A photo-etching method, a method using a mask in advance, or the like is used for patterning these transparent conductive films. In applying the liquid crystal aligning agent, in order to further improve the adhesion between the substrate and the transparent conductive film and the coating film, a functional silane-containing compound, titanate, or the like may be applied on the substrate and the transparent conductive film in advance. it can. The firing temperature is usually 80 to 250 ° C, preferably 120 to 2 ° C.
00 ° C. The film thickness of the formed film is usually 0.0
It is from 0.01 to 1 μm, preferably from 0.005 to 0.5 μm.

(2) The formed film is subjected to a rubbing treatment of rubbing in a certain direction with a roll around which a cloth made of a synthetic fiber such as nylon is wound, so that the film is provided with the ability to align liquid crystal molecules. Becomes In addition to the method using a rubbing treatment, a method of irradiating polarized ultraviolet light to the coating surface to impart orientation ability, a uniaxial stretching method, a Langmuir method,
The liquid crystal alignment film can also be formed by a method of obtaining a film by a blow jet method or the like. Note that the formed liquid crystal alignment film is preferably washed with isopropyl alcohol or the like in order to remove fine powder (foreign matter) generated during the rubbing treatment and keep the surface clean. Also,
For example, JP-A-6-222366 and JP-A-6-281 disclose a liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention.
No. 937, a process in which the pretilt angle is changed by partially irradiating ultraviolet rays, or a rubbed liquid crystal, as described in JP-A-5-107544. After partially forming a resist film on the alignment film, performing a rubbing process in a direction different from the preceding rubbing process, removing the resist film, and performing a process of changing the alignment ability of the liquid crystal alignment film. By doing so, it is possible to improve the visibility characteristics of the liquid crystal display element.

(3) Two substrates on which the liquid crystal alignment films are formed as described above are prepared, and the two substrates are separated by a gap so that the rubbing directions of the respective liquid crystal alignment films are orthogonal or antiparallel. (A cell gap), the peripheral portions of the two substrates are bonded together with a sealant, liquid crystal is filled into the surface of the substrate and the cell gap defined by the sealant, and the filling hole is sealed. To form a liquid crystal cell.
Then, a polarizing plate is provided 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. Thus, a liquid crystal display element is obtained. As the sealant,
For example, an epoxy resin containing a hardening agent and aluminum oxide spheres as a spacer can be used. Examples of the liquid crystal include a nematic liquid crystal and a smectic liquid crystal. Among them, a nematic liquid crystal is preferable.For example, a Schiff base liquid crystal, an azoxy liquid crystal, a biphenyl liquid crystal, a phenylcyclohexane liquid crystal, an ester liquid crystal, and a terphenyl liquid crystal. Liquid crystal, biphenylcyclohexane liquid crystal, pyrimidine liquid crystal, dioxane liquid crystal, bicyclooctane liquid crystal, cubane liquid crystal, and the like are used. In addition, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonaate and cholesteryl carbonate, and chiral agents sold under the trade names “C-15” and “CB-15” (manufactured by Merck & Co.) It can also be used by adding it. In addition, ferroelectric liquid crystals such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate can be used. Further, as a polarizing plate used outside the liquid crystal cell, a polarizing plate in which a polarizing film called an H film absorbing iodine is sandwiched between cellulose acetate protective films while stretching and aligning polyvinyl alcohol,
Alternatively, a polarizing plate composed of the H film itself can be used.

[0043]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. Each of the liquid crystal display devices manufactured by the following examples and comparative examples was evaluated for the liquid crystal alignment of the liquid crystal display device and the afterimage erasing time. The evaluation method is as follows. [Liquid Crystal Alignment of Liquid Crystal Display Element] The presence or absence of an abnormal domain in the liquid crystal display element when the voltage was turned on / off in the liquid crystal display element was observed with a polarizing microscope. [Afterimage erasing time] The afterimage erasing time was measured by applying a 10 V DC voltage to the liquid crystal cell for 1 hour, turning off the voltage, and visually erasing the afterimage. [Imidation rate of imidized polymer] The imidized polymer was dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR was measured. The imidation ratio was calculated from the ratio of the number of hydrogen atoms attributed to the amide group to the number of other hydrogen atoms in the obtained ¹ H-NMR spectrum.

<Synthesis Example 1> 1, 3, 3a, 4, 5, 9b
-Hexahydro-8-methyl-5- (tetrahydro-
2,5-dioxo-3-furanyl) -naphtho [1,2-
c] Furan-1,3-dione 42.08 g, p-phenylenediamine 8.69 g, 11.31 g of the compound represented by the above formula (16) and 2,6-diaminopyridine
92 g was dissolved in 260 g of N-methyl-2-pyrrolidone and reacted at room temperature for 24 hours. In the obtained reaction solution,
950 g of N-methyl-2-pyrrolidone, pyridine
After adding 9 g and 41 g of acetic anhydride, respectively, and performing a dehydration ring closure reaction at 80 ° C. for 3 hours, the reaction solution was poured into a large amount of methanol to precipitate and purify, and the intrinsic viscosity was 1.49 dl /.
g, a polymer (1) having an imidation ratio of 100% was obtained. <Synthesis Example 2> 1,3,3a, 4,5,9b-Hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-
40.87 g of 1,3-dione, 5.63 g of p-phenylenediamine, 6.77 of the compound represented by the above formula (16)
g, 10.31 g of diaminodiphenylmethane and 2,
1.42 g of 6-diaminopyridine was dissolved in 260 g of N-methyl-2-pyrrolidone and reacted at room temperature for 24 hours. 900 g of N-methyl-2-pyrrolidone, 41.1 g of pyridine and 92.9 of acetic anhydride were added to the obtained reaction solution.
g, and the mixture was subjected to a dehydration ring-closing reaction at 80 ° C. for 3 hours. Then, the reaction solution was poured into a large amount of methanol for precipitation and purification, and a polymer (2) having an intrinsic viscosity of 1.4 dl / g and an imidation ratio of 100% was added. ) Got. <Synthesis Example 3> In Synthesis Example 1, compound 6.88 represented by the above formula (9) is used instead of 2,6-diaminopyridine.
Except that g was used, the intrinsic viscosity was 1.
A polymer (3) having 5 dl / g and an imidation ratio of 99% was obtained. <Synthesis Example 4> In Synthesis Example 1, compound represented by the above formula (10) instead of 2,6-diaminopyridine.
Polymer (4) having an intrinsic viscosity of 1.4 dl / g and an imidation ratio of 99% was obtained in the same manner as in Synthesis Example 2 except that 87 g was used.

Synthesis Example 5 36.0 g of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 25.5 g of diaminodiphenylmethane and 3.5 g of 2,6-diaminopyridine were added to 260 g of N-methyl-2-pyrrolidone. It was dissolved and reacted at room temperature for 12 hours. To the obtained reaction solution, N-methyl-2-pyrrolidone (1000 g), pyridine (63.5 g) and acetic anhydride (49.2 g) were added, respectively.
After performing the dehydration ring-closure reaction at 110 ° C. for 3 hours, the reaction solution was poured into a large amount of methanol to precipitate and purify the solution.
A polymer (5) having 29 dl / g and an imidation ratio of 99% was obtained. <Synthesis Example 6> In Synthesis Example 5, except that 19.1 g of diaminodiphenylmethane and 6.97 g of 2,6-diaminopyridine were used as the diamine, an intrinsic viscosity of 1.1 dl / g and imidization were used. A polymer (6) having a ratio of 99% was obtained. <Synthesis Example 7> An intrinsic viscosity of 1.0 d was obtained in the same manner as in Synthesis Example 6, except that 3.5 g of 2,4-diaminopyrimidine was used instead of 2,6-diaminopyridine.
1 / g, a polymer (7) having an imidation ratio of 99% was obtained.

<Synthesis Example 8> Pyromellitic dianhydride 4
2.07 g and diaminodiphenylmethane 30.95
g in 260 g of N-methyl-2-pyrrolidone,
The reaction was performed at room temperature for 3 hours. The reaction solution was poured into a large amount of methanol for precipitation and purification to obtain a polymer (8) having an intrinsic viscosity of 1.80 dl / g and an imidation ratio of 0%. <Synthesis Example 9> 43.15 g of 2,3,5-tricarboxycyclopentylacetic acid dianhydride and 21.8 g of p-phenylenediamine were added to 260 g of N-methyl-2-pyrrolidone.
And reacted at room temperature for 6 hours. To the obtained reaction solution, 1005 g of N-methyl-2-pyrrolidone, 15.2 g of pyridine and 19.6 g of acetic anhydride were respectively added, and a dehydration ring closure reaction was performed at 110 ° C. for 3 hours, and the reaction solution was added to a large amount of methanol. The mixture was poured, precipitated and purified to obtain a polymer (9) having an intrinsic viscosity of 0.80 dl / g and an imidation ratio of 40%.

Example 1 5 g of the polymer (1) obtained in Synthesis Example 1 was dissolved in γ-butyrolactone to obtain a solution having a solid concentration of 4% by weight, and this solution was filtered through a filter having a pore size of 1 μm. A liquid crystal aligning agent was prepared. The above liquid crystal aligning agent is applied on a glass substrate with a transparent electrode made of an ITO film using a printing machine for coating a liquid crystal alignment film,
After baking for a time, a coating film having a dry film thickness of 0.05 μm was formed.
A rubbing machine having a roll in which a rayon cloth is wound around this coating film is used to rotate the roll at 400 rpm.
The rubbing treatment was performed at a m, stage moving speed of 3 cm / sec, and a hair foot indentation length of 0.4 mm. Next, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 17 μm is screen-printed and applied to each outer edge of the pair of rubbed substrates having the liquid crystal alignment film, and then the pair of substrates face each other. As described above, the rubbing direction was perpendicular to the rubbing direction, and the adhesive was cured by pressing. Next, after filling a nematic liquid crystal (MLC-2001, manufactured by Merck) between the pair of substrates from the liquid crystal injection port, the liquid crystal injection port is sealed with an epoxy-based adhesive, and polarizing plates are provided on both outer surfaces of the substrate. Were bonded so that the polarization direction of the polarizing plate coincided with the rubbing direction of the liquid crystal alignment film of each substrate, to produce a liquid crystal display device. The orientation of the liquid crystal of the obtained liquid crystal display element was good, and the afterimage erasing time was an extremely small value of 0.3 seconds. Table 1 shows the results.

Examples 2 to 9 and Comparative Examples 1 to 2 Using the polymers (2) to (9) obtained in Synthesis Examples 2 to 9,
A liquid crystal alignment agent was prepared in the same manner as in Example 1, and the performance of the liquid crystal display device was evaluated. Table 1 shows the results.

[0049]

[Table 1] (In the tables, the ratios of the polymers in Examples 8 and 9 are weight ratios.)

[0050]

The liquid crystal aligning agent of the present invention can be fired at a low temperature, has good alignment of the liquid crystal, and can obtain a liquid crystal alignment film having an extremely short residual image erasing time when applying a liquid crystal cell. The liquid crystal display device having a liquid crystal alignment film formed using the liquid crystal alignment agent of the present invention can be suitably used for TN type and STN type liquid crystal display devices, and can be further provided by selecting SH (Super Homeotropic) by selecting a liquid crystal to be used. ) Type, IPS (In-Plane)
It can also be suitably used for (Switcing) type, ferroelectric and antiferroelectric liquid crystal display devices. Further, a liquid crystal display device having a liquid crystal alignment film formed using the liquid crystal alignment agent of the present invention can be effectively used for various devices, for example, a desk calculator, a wristwatch, a clock, a coefficient display plate, a word processor, a personal computer, and a liquid crystal. Used for display devices such as televisions.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuaki Rokka 2--11-24 Tsukiji, Chuo-ku, Tokyo Inside Nippon Gosei Rubber Co., Ltd. (72) Inventor Yasuo Matsuki 2--11 Tsukiji, Chuo-ku, Tokyo No. 24 Nippon Synthetic Rubber Co., Ltd.

Claims (1)

[Claims] 1. It has a repeating unit represented by the following formula (A) and has an intrinsic viscosity [ηinh] (measured in an N-methylpyrrolidone solvent of 0.5 g / dl at 30 ° C.).
A liquid crystal aligning agent comprising an imidized polymer having a content of from 0.05 to 10 dl / g. Embedded image (In the formula, R ¹ is a tetravalent organic group, and R ² is a divalent organic group having a nitrogen atom.)