JPH1046151A - Liquid crystal aligning agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystal aligning agent which can form a non- peelable liquid crystal alignment film on a transparent electrode base by mixing a polyamic acid or an imide polymer derived therefrom with a specified compound. SOLUTION: This agent comprises at least one polymer selected among polyamic acids and imide polymers prepared therefrom and a compound having an organic group represented by the formula (wherein X is an alkyl or H) in the molecule. A liquid crystal display element provided with a liquid crystal alignment film formed by using the liquid crystal aligning agent scarcely forms a residual image on the display screen because the residual voltage after the release of the applied voltage is small and can develop high-contrast excellent display performances. The liquid crystal display element provided with this alignment film has excellent liquid crystal aligning performances and reliability and can be desirably used in the display of, e.g. a table calculator, a wrist watch, a clock, a count display panel, a word processor, a personal computer or a liquid crystal television set.

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, and more particularly, to a liquid crystal aligning agent containing a polyamic acid and / or an imidized polymer of a polyamic acid and a compound having a specific group in the molecule. Agent.

[0002]

2. Description of the Related Art At present, as a liquid crystal display element, a liquid crystal alignment film is formed on the surface of a substrate on which a transparent conductive film is provided to form a substrate for a liquid crystal display element. A nematic liquid crystal layer having a positive dielectric anisotropy is formed in the gap to form a sandwich cell, and the major axis of the liquid crystal molecules is continuously twisted 90 degrees from one substrate toward the other substrate. The so-called TN (Tw
TN having isted Nematic type liquid crystal cell
2. Description of the Related Art Liquid crystal display elements are known. Recently, STN (Super Tw) has higher contrast than TN-type liquid crystal display elements and has less viewing angle dependence.
An isotropic nematic liquid crystal display device has been developed. This STN-type liquid crystal display element uses a nematic liquid crystal blended with a chiral agent as an optically active substance as a liquid crystal, and the major axis of the liquid crystal molecule is 1 between the substrates.
It utilizes the birefringence effect caused by a continuous twisting state over 80 degrees. Orientation of liquid crystal molecules in these liquid crystal display elements is usually exhibited by a liquid crystal alignment film formed by performing a rubbing treatment on the surface of a film made of a polymer. Here, polyamic acid and polyimide are known as a polymer constituting the above-mentioned film, and a liquid crystal aligning agent obtained by dissolving these polymers in a solvent is generally used.

[0003]

However, since the film formed by the conventional liquid crystal aligning agent does not have sufficient toughness against the rubbing force, when the surface of the film is subjected to a rubbing treatment, Of the formed liquid crystal alignment film,
In some cases, peeling (hereinafter also referred to as “film shaving”) may occur from the substrate, and in a liquid crystal display device having such a liquid crystal alignment film, display defects due to film shaving may occur. is there. Further, in a liquid crystal display device provided with a liquid crystal alignment film formed by a conventional liquid crystal alignment agent, ionic charges generated during image display (during voltage application) and adsorbed on the liquid crystal alignment film are removed after image erasure ( (After release of voltage application)
However, there is a problem that the voltage is not desorbed from the liquid crystal alignment film, the voltage remains in the liquid crystal alignment film after the voltage is released, and a residual image is generated on the display screen after the release of the voltage due to the residual voltage. When such an afterimage occurs, the difference in brightness between when the voltage is applied and when the voltage is released becomes small, and good contrast cannot be obtained. First of the present invention
An object of the present invention is to provide a liquid crystal aligning agent capable of forming a liquid crystal alignment film without film shaving on a transparent electrode substrate. A second object of the present invention is to provide a liquid crystal display device having a liquid crystal alignment film to be formed, in which a residual voltage after the application of a voltage is released is small and an afterimage is hardly generated on a display screen,
An object of the present invention is to provide a liquid crystal aligning agent capable of exhibiting excellent display performance with high contrast.

[0004]

Means for Solving the Problems The liquid crystal aligning agent of the present invention comprises:
[A] at least one polymer selected from polyamic acids and imidized polymers of polyamic acids, and [b] the following formula (I): (In the formula, X represents an alkyl group or a hydrogen atom.) A compound having an organic group represented by the formula (hereinafter, also referred to as “compound (I)”) is contained. Hereinafter, the present invention will be described in detail.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION

<(A) Polyamic acid> The polyamic acid constituting the liquid crystal aligning agent of the present invention can be prepared by reacting a tetracarboxylic dianhydride with a diamine compound.

Examples of the tetracarboxylic dianhydride used in the synthesis reaction 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, 1,2,2
4,5-cyclohexanetetracarboxylic dianhydride,
3,3 ′, 4,4′-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 3,5,6-tricarboxynorbornane-2-acetic dianhydride, , 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, 4,5,9
b-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, 1,3,3
a, 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, aliphatic and alicyclic tetracarboxylic dianhydrides such as compounds represented by the following formulas (1) and (2);

[0007]

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(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 present. , May be the same or different.)

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′-biphenylethertetracarboxylic 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-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'-diphenyl ether dianhydride, bis (tri Phenylphthalic acid) -4,4′-diphenylmethane dianhydride, ethylene glycol-bis (anhydrotrimellitate), propylene glycol-bis (anhydrotrimellitate), 1,4-butanediol-bis (anhydrotrimeritate) Trimellitate), 1,6-hexanediol-bis (anhydrotrimellitate),
1,8-octanediol-bis (anhydrotrimellitate), 2,2-bis (4-hydroxyphenyl) propane-bis (anhydrotrimellitate), represented by the following formulas (3) to (6) And aromatic tetracarboxylic dianhydrides such as These are used alone or in combination of two or more.

[0010]

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Of these, butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride Anhydride, 1,2,3,4-
Cyclopentanetetracarboxylic dianhydride, 2,3,5
-Tricarboxycyclopentylacetic 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 dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′- Biphenylsulfonetetracarboxylic dianhydride, 1,4
5,8-Naphthalenetetracarboxylic dianhydride, among the compounds represented by the formula (1), the compounds represented by the following formulas (7) to (9) and the compound represented by the following formula (2): The compound represented by (10) is preferable from the viewpoint of exhibiting good liquid crystal alignment, and particularly preferable are 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,3-dimethyl. −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 3
a, 4,5,9b-Hexahydro-8-methyl-5-
(Tetrahydro-2,5-dioxo-3-furanyl)-
Examples thereof include naphtho [1,2-c] furan-1,3-dione, pyromellitic dianhydride and a compound represented by the following formula (7).

[0012]

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Examples of the diamine compound used in the synthesis reaction of the polyamic acid include p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane,
4,4'-diaminodiphenyl sulfide, 4,4'-
Diaminodiphenyl sulfone, 3,3'-dimethyl-
4,4'-diaminobiphenyl, 4,4'-diaminobenzanilide, 4,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 3,3-dimethyl-
4,4′-diaminobiphenyl, 5-amino-1- (4′-aminophenyl) -1,3,3-trimethylindane, 6-amino-1- (4′-aminophenyl) -1,3,3-trimethylindane, 3,4 ′ -Diaminodiphenyl ether, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2- Screw [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-hydro Anthracene, 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'-
Aromatic diamines such as bis (trifluoromethyl) biphenyl and 4,4′-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 (11); a diaminoorganosiloxane represented by the following formula (12):

[0016]

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(Wherein R ⁵ represents —O—, —COO—,
OCO-, -NHCO-, -CONH- and -CO-
And R ⁶ represents a monovalent organic group having a steroid skeleton or a trifluoromethyl group. )

[0018]

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(Wherein R ⁷ represents a hydrocarbon group having 1 to 12 carbon atoms, a plurality of R ^{7 s} 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 (13) to (17). These diamine compounds can be used alone or in combination of two or more.

[0021]

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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, 4,4'-diaminodiphenylsulfide, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 4,4'-diaminodiphenylether, 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, compounds represented by the above formulas (13) to (17), and compounds represented by the following formulas (18) to (22) among the compounds represented by the above formula (17) are preferable. These diamines may be used as they are, or may be used after being reduced again.

[0024]

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The ratio of the tetracarboxylic dianhydride and the diamine compound used in the synthesis reaction of the polyamic acid is such that the ratio of the acid contained in the tetracarboxylic dianhydride to the equivalent of the amino group contained in the diamine compound is 1 equivalent. The ratio is preferably 0.2 to 2 equivalents of the anhydride group, more preferably 0.3 to 1.4 equivalents. In both cases where the ratio of the acid anhydride groups contained in the tetracarboxylic dianhydride is less than 0.2 equivalent or more than 2 equivalents, the molecular weight of the obtained polymer becomes too small and the application of the liquid crystal aligning agent is performed. The properties may be poor.

The polyamic acid constituting the liquid crystal aligning agent in the present invention is synthesized by reacting a tetracarboxylic dianhydride with a diamine compound. The synthesis reaction of the polyamic acid is carried out in an organic solvent under a temperature condition of usually 0 to 150 ° C, preferably 0 to 100 ° C. Reaction temperature is 0
When the temperature is lower than or equal to ° C, the solubility of the compound in a solvent may be inferior. When the temperature exceeds 150 ° C, the molecular weight of the obtained polymer may decrease.

The organic solvent used for the synthesis of the polyamic acid is not particularly limited as long as it can dissolve the tetracarboxylic dianhydride, the diamine compound and the polyamic acid produced by the reaction. For example, γ-butyrolactone, N Aprotic systems such as -methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, tetramethylurea, hexamethylphosphoryltriamide, 1,3-dimethyl-2-imidazolidinone Polar solvents; phenolic solvents such as m-cresol, xylenol, phenol, halogenated phenol and the like can be mentioned.

The amount (a) of the organic solvent used is such that the total amount (b) of the tetracarboxylic dianhydride and the diamine compound as the reaction raw materials is 0.1 to 3 with respect to the total amount (a + b) of the reaction solution.
Preferably, the amount is 0% by weight.

The above organic solvents include alcohols, ketones, esters which are poor solvents for polyamic acid,
Ethers, halogenated hydrocarbons, hydrocarbons and the like can be used in combination as long as the generated polyamic acid does not precipitate. Specific examples of such poor solvents include, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol,
Triethylene glycol, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate,
Diethyl malonate, diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl 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, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether Le, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, ethylene glycol ethyl ether acetate, 4
-Hydroxy-4-methyl-2-pentanone, ethyl 2-hydroxypropionate, ethyl lactate, methyl lactate,
Butyl lactate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3-
Methyl methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, 3-methyl-3-methoxybutanol, 3-ethyl-3-methoxybutanol, 2-methyl-2-methoxybutanol,
2-ethyl-2-methoxybutanol, 3-methyl-3
-Ethoxybutanol, 3-ethyl-3-ethoxybutanol, 2-methyl-2-ethoxybutanol, 2-ethyl-2-ethoxybutanol, tetrahydrofuran,
Dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-
Examples thereof include dichlorobenzene, hexane, heptane, octane, benzene, toluene, and xylene. These can be used alone or in combination of two or more.

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

<(A) Imidized polymer> The imidized polymer constituting the liquid crystal aligning agent of the present invention is prepared by the following methods (1) to (4).
It can be prepared by (3) and is usually a polyimide and / or polyisoimide.

Method (1): A method of heating a polyamic acid to effect dehydration ring closure. The reaction temperature in this method is usually from 60 to 200 ° C, preferably from 100 to 170 ° C. When the reaction temperature is lower than 60 ° C., the imidization reaction does not proceed sufficiently, and when the reaction temperature is higher than 200 ° C., the molecular weight of the specific polymer (II) obtained may be small.

Method (2): A method in which a polyamic acid is dissolved in an organic solvent, a dehydrating agent and an imidization catalyst are added to the solution, and the solution is heated if necessary. In this method, as the dehydrating agent, for example, acetic anhydride,
Acid anhydrides such as propionic anhydride and trifluoroacetic anhydride can be used. The amount of the dehydrating agent used is preferably 1.6 to 20 mol per 1 mol of the repeating unit of the polyamic acid. 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 imidation catalyst used is preferably 0.5 to 10 mol per 1 mol of the dehydrating agent used. In addition, as the organic solvent used for the imidization reaction, the organic solvents exemplified as those used for the synthesis of the polyamic acid can be exemplified. And the reaction temperature of the imidization reaction is usually 0 to 180 ° C, preferably 60 to 150 ° C.

Method (3): A method in which tetracarboxylic dianhydride and a diisocyanate compound are mixed and condensed. Specific examples of the diisocyanate compound used in this method include: an aliphatic diisocyanate compound such as hexamethylene diisocyanate; an alicyclic diisocyanate compound such as cyclohexane diisocyanate; diphenylmethane-4,4'-diisocyanate, diphenylether-4,4'- Diisocyanate, diphenylsulfone-4,4'-diisocyanate, diphenylsulfide-4,4'-diisocyanate, 1,2-diphenylethane-p, p'-diisocyanate, 2,2-diphenylpropane-p, p'-diisocyanate, 2,2-diphenyl-1,1,1,3,3,3-hexafluoropropane-p, p'-diisocyanate, 2,2-diphenylbutane-p, p'-diisocyanate, diphenyl dichloromethane-4,4 ' -Diisocyanates, diphs Aromatic diisocyanate compounds such as nylfluoromethane-4,4′-diisocyanate, benzophenone-4,4′-diisocyanate, and N-phenylbenzoic acid amide-4,4′-diisocyanate can be given, either alone or Two or more can be used in combination. This method does not require a catalyst, and the reaction temperature is usually 50 to 200 ° C., preferably 100 to 160 ° C.
° C. For the polymer solution thus obtained,
By performing the same operation as the method for purifying a polyamic acid, the imidized polymer can be purified.

<Intrinsic viscosity of polyamic acid and imidized polymer> The intrinsic viscosity of the polyamic acid and imidized polymer obtained as described above (30 ° C, N-methyl-
Measured in 2-pyrrolidone. The same applies hereinafter. ) Is usually 0.05 to 10 dl / g, preferably 0.05 to 5 dl.
/ G.

<Terminal-Modified Polymer> The polyamic acid and / or imidized polymer constituting the liquid crystal aligning agent of the present invention may be a terminal-modified polymer. The molecular weight of the terminal-modified polymer is controlled, and the coating characteristics of the liquid crystal aligning agent can be improved without impairing the effects of the present invention. The terminal-modified polymer can be synthesized by adding an acid anhydride, a monoamine compound or a monoisocyanate compound to the reaction system when synthesizing the polyamic acid.

The acid anhydride to be added to the reaction system for synthesizing the polyamic acid to obtain a terminal-modified polymer includes, for example, maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic acid Anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride, n-hexadecyl succinic anhydride and the like can be mentioned. Examples of the monoamine added to the reaction system include, for example, aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosyl Examples include amines. In addition, examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

<Compound (I)> The liquid crystal aligning agent of the present invention comprises:
It is characterized in that a compound having the organic group represented by the above formula (I) in the molecule is contained. By forming a liquid crystal alignment film using a liquid crystal alignment agent containing such a compound and manufacturing a liquid crystal display element, a residual voltage which causes an afterimage can be reduced after the voltage application is released. As a result, the liquid crystal display element has excellent display performance with high contrast.

In the above formula (I), X represents an alkyl group or a hydrogen atom.
~ 6 alkyl groups are preferred. As the compound (I), preferred are, for example, compounds represented by the following formulas (I-1) to
The compound shown by (I-4) can be mentioned. These compounds can be used alone or in combination of two or more.

[0040]

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(Wherein, X ¹ represents an alkyl group or a hydrogen atom, and X ² represents an organic group or a hydrogen atom represented by the following formula (i): —CH ₂ OX ¹ (i))

The compound represented by the above formula (I-1)
-A melamine having a substituted alkoxymethyl group or a methylol group, such as N, N, N, N, N, N- (hexamethoxymethyl) melamine. The compound may include a compound obtained by introducing an organic group represented by the above formula (I) into a melamine-formaldehyde resin. Commercial products of melamine containing an N-substituted alkoxymethyl group or a methylol group include, for example, Cymel 300, Cymel 301, Cymel 303, Cymel 350, Cymel 736, Cymel 738, Cymel 370, Cymel 771, Cymel 325, Cymel 3
27, Cymel 703, Cymel 701, Cymel 26
6, Cymel 267, Cymel 285, Cymel 23
2, Cymel 235, Cymel 238, Cymel 114
1, Cymel 272, Cymel 254, Cymel 20
2, Cymel 1156, Cymel 1158 (manufactured by Mitsui Cytec Co., Ltd.) and the like.

The compound represented by the above formula (I-2)
-A benzoguanamine containing a substituted alkoxymethyl group or a methylol group, such as N, N '-(dibutoxymethyl) benzoguanamine. The compound may include a compound obtained by introducing an organic group represented by the above formula (I) into a benzoguanamine-formaldehyde resin. Commercially available benzoguanamines containing an N-substituted alkoxymethyl group or a methylol group include, for example, Cymel 1123 and Cymel 1123-1.
0, Cymel 1125-80, Cymel 1128 (manufactured by Mitsui Cytec Co., Ltd.) and the like.

The compound represented by the above formula (I-3)
-Glycoluril containing a substituted alkoxymethyl group or a methylol group, such as N, N, N, N,-
(Tetramethoxymethyl) glycoluril and the like. The compound may include a compound obtained by introducing an organic group represented by the above formula (I) into a glycoluril-formaldehyde resin. Commercial products of glycoluril containing an N-substituted alkoxymethyl group or a methylol group include, for example, Cymel 1170 and Cymel 1170.
171, Cymel 1174, Cymel 1172 (manufactured by Mitsui Cytec Co., Ltd.) and the like.

The compound represented by the above formula (I-4) is
-A urea containing a substituted alkoxymethyl group or a methylol group, such as N, N, N, N- (tetramethoxymethyl) urea. The compound may include a compound obtained by introducing an organic group represented by the above formula (I) into a urea-formaldehyde resin. Examples of commercially available urea containing an N-substituted alkoxymethyl group or a methylol group include UFR65 and UFR300 (manufactured by Mitsui Cytec Co., Ltd.).

As the compound (I), thiourea-formaldehyde resin, guanamine-
A compound in which an organic group represented by the above formula (I) is introduced into a formaldehyde resin or the like can be given.

Further, a latent acid generator may be added to the liquid crystal aligning agent of the present invention in order to accelerate the reaction of compound (I). Examples of the latent acid generator include a cationic polymerization catalyst that generates an acid by heating, and specifically, onium salts such as sulfonium salts, benzothiazolium salts, ammonium salts, and phosphonium salts are used. . Among them, sulfonium salts and benzothiazolium salts are preferred.

Specific examples of the above sulfonium salt include 4
-Acetophenyldimethylsulfonium hexafluoroantimonate, 4-acetoxyphenyldimethylsulfonium hexafluoroarsenate, dimethyl-4-
(Benzyloxycarbonyloxy) phenylsulfonium hexafluoroantimonate, dimethyl-4-
Alkylsulfonium salts such as (benzoyloxy) phenylsulfonium hexafluoroantimonate, dimethyl-4- (benzoyloxy) phenylsulfonium hexafluoroarsenate, dimethyl-3-chloro-4-acetoxyphenylsulfonium hexafluoroantimonate; benzyl-4 -Hydroxyphenylmethylsulfonium hexafluoroantimonate, benzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate, 4-acetoxyphenylbenzylmethylsulfonium hexafluoroantimonate, benzyl-4-methoxyphenylmethylsulfonium hexafluoroantimonate, benzyl-2 -Methyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate DOO, benzyl-3-chloro-4-
Monobenzylsulfonium salts such as hydroxyphenylmethylsulfonium hexafluoroarsenate and 4-methoxybenzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate; dibenzyl-4
-Hydroxyphenylsulfonium hexafluoroantimonate, dibenzyl-4-hydroxyphenylsulfonium hexafluorophosphate, 4-acetoxyphenyldibenzylsulfonium hexafluoroantimonate, dibenzyl-4-methoxyphenylsulfonium hexafluoroantimonate, dibenzyl-3-
Chloro-4-hydroxyphenylsulfonium hexafluoroarsenate, dibenzyl-3-methyl-4-hydroxy-5-tert-butylphenylsulfonium hexafluoroantimonate, benzyl-4-methoxybenzyl-4-hydroxyphenylsulfonium hexafluorophosphate, etc. Dibenzylsulfonium salt of p-chlorobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, p-nitrobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, p-chlorobenzyl-4-hydroxyphenylmethylsulfonium hexa Fluorophosphate, p-nitrobenzyl-3-methyl-4-hydroxyphenylmethylsulfonium hexafluoroantimony Over DOO, 3,5-dichlorobenzyl -
Substituted benzylsulfonium salts such as 4-hydroxyphenylmethylsulfonium hexafluoroantimonate, o-chlorobenzyl-3-chloro-4-hydroxyphenylmethylsulfonium hexafluoroantimonate; sulfonium represented by the following formulas (23) to (29) Salts.

[0049]

Embedded image

Specific examples of the benzothiazonium salt include 3-benzylbenzothiazolium hexafluoroantimonate, 3-benzylbenzothiazolium hexafluorophosphate, 3-benzylbenzothiazolium tetrafluoroborate, Benzyl such as-(p-methoxybenzyl) benzothiazolium hexafluoroantimonate, 3-benzyl-2-methylthiobenzothiazolium hexafluoroantimonate, 3-benzyl-5-chlorobenzothiazolium hexafluoroantimonate Benzothiazolium salts are mentioned.

Of these, 4-acetoxyphenyldimethylsulfonium hexafluoroarsenate, benzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, 4-acetoxyphenylbenzylmethylsulfonium hexafluoroantimonate, dibenzyl-4-hydroxyphenylsulfonium Hexafluoroantimonate, 4-acetoxyphenylbenzylsulfonium hexafluoroantimonate, 3-benzylbenzothiazolium hexafluoroantimonate and the like are preferably used. These commercial products include Sun-Aid SI-L85 and SI-L11
0, same SI-L145, same SI-L150, same SI-L
160 (manufactured by Sanshin Chemical Industry Co., Ltd.). These compounds can be used alone or in combination of two or more.

<Liquid Crystal Alignment Agent> The liquid crystal alignment agent of the present invention comprises a component (a) composed of polyamic acid and / or an imidized polymer of polyamic acid and a component (b) composed of the compound (I). It is constituted by being dissolved and contained in a solvent.

The content ratio (polymer concentration) of the component (a) in the liquid crystal aligning agent of the present invention is selected in consideration of viscosity, volatility and the like, but is preferably 0.1 to 10% based on the whole solution.
20% by weight, more preferably 0.5 to 10% by weight
It is said. When the concentration is less than 0.1% by weight, the thickness of the coating film (coating) becomes too small to obtain a good liquid crystal alignment film, while the concentration exceeds 20% by weight. In such a case, the film thickness of the coating film becomes excessively large, making it difficult to obtain a good liquid crystal alignment film. In addition, the viscosity of the liquid crystal alignment agent is increased, and the coating properties may be deteriorated. As the content ratio of the component (b) in the liquid crystal aligning agent of the present invention, the ratio of the component (b) to 100 parts by weight of the component (a) is usually 0.0
The content is 1 to 30 parts by weight, preferably 0.01 to 20 parts by weight. If the content of the component (b) is less than 0.01 part by weight, the effect of reducing the residual voltage may not be sufficiently achieved, while the content of the component (b) may be less than 30 parts.
If the amount exceeds the weight part, the surface of the film formed by the obtained liquid crystal aligning agent may be roughened. In addition,
The organic solvent for dissolving the component (a) and the component (b) is not particularly limited as long as they can dissolve the components, and examples thereof include the solvents exemplified as those used for the synthesis of polyamic acid. Can be. 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 for the purpose of further improving the adhesion to the substrate. Examples of such functional silane-containing compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, and N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N-
(2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3 -Aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxyisyl-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-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyltrimethoxy Silane, N-bis (oxyethylene)
And -3-aminopropyltriethoxysilane.

<Liquid Crystal Display Device> A liquid crystal display device obtained by using the liquid crystal aligning agent of the present invention can be manufactured, for example, by the following method.

(1) The liquid crystal aligning agent of the present invention is applied to one surface of a substrate on which a patterned transparent conductive film is provided, for example, by a roll coater method, a spinner method, a printing method or the like, and then the coated surface To form a film. Here, as the substrate, for example, a transparent substrate made of glass such as float glass or soda glass; or a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, or polycarbonate can be used. As the transparent conductive film provided on one surface of the substrate, tin oxide (SnO)
2), an NESA film (registered trademark of PPG, USA), an indium oxide-tin oxide (In 2 O 3 —SnO 2) ITO film, and the like can be used. Alternatively, a method using a mask in advance is used. In applying the liquid crystal aligning agent, in order to further improve the adhesion between the substrate surface and the transparent conductive film and the liquid crystal aligning agent film, a functional silane-containing compound, a functional titanium-containing compound, etc. Can be applied in advance. The heating temperature is 80
To 250 ° C, preferably 120 to 200 ° C. The thickness of the film to be formed is usually 0.001 to 1 μm
And preferably 0.005 to 0.5 μm. Incidentally, the liquid crystal aligning agent of the present invention containing a polyamic acid,
After the application, the organic solvent is removed to form a film serving as a liquid crystal alignment film. By further heating, dehydration ring closure proceeds to form a partially or completely imidized film.

(2) A rubbing treatment is performed in which the surface of the film formed by the liquid crystal aligning agent is rubbed in a certain direction with a roll around which a cloth made of fibers such as nylon, rayon or cotton is wound. As a result, the alignment ability of liquid crystal molecules is imparted to the film, and a liquid crystal alignment film is formed. In addition to the rubbing treatment method, a liquid crystal alignment film is formed by irradiating polarized ultraviolet light to the resin film surface to impart alignment ability, or by forming a film by a uniaxial stretching method, a Langmuir-Blodgett method, or the like. You can also. Note that, in order to remove fine powder (foreign matter) generated during the rubbing treatment and keep the surface clean, it is preferable to wash the formed liquid crystal alignment film with isopropyl alcohol or the like. In addition, a process of changing the pretilt angle by partially irradiating the surface of the formed liquid crystal alignment film with ultraviolet rays (for example, JP-A-6-222366, JP-A-6-281937).
Japanese Patent Application Laid-Open No. H10-157, a resist film is partially formed on the surface of the formed liquid crystal alignment film, a rubbing process is performed in a direction different from the preceding rubbing process, and then the resist film is removed. (See, for example, Japanese Patent Application Laid-Open No. 5-107544) can improve the viewing angle characteristics of a liquid crystal display device to be manufactured.

(3) Two substrates on each of which a liquid crystal alignment film is formed as described above are prepared, and the two substrates are aligned so that the alignment treatment direction, that is, the rubbing direction in each liquid crystal alignment film is orthogonal or antiparallel. Substrates are arranged to face each other with a gap (cell gap) therebetween, the peripheral portions of the two substrates are bonded together with a sealant, and liquid crystal is injected and filled into the substrate surface and the cell gap defined by the sealant. Then, the injection 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.

Here, as the sealant, for example, an epoxy resin containing aluminum oxide spheres as a curing agent and 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,
Biphenyl-based liquid crystal, phenylcyclohexane-based liquid crystal, ester-based liquid crystal, terphenyl-based liquid crystal, biphenylcyclohexane-based liquid crystal, pyrimidine-based liquid crystal, dioxane-based liquid crystal, bicyclooctane-based liquid crystal, cubane-based liquid crystal, and the like can be used. In addition, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonaate, and cholesteryl carbonate, and chiral agents such as those sold under the trade names "C-15" and "CB-15" (manufactured by Merck & Co.) It can also be used by adding it. Further, p-decyloxybenzylidene-p
Ferroelectric liquid crystals such as -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 plate or an H film in which a polarizing film called an H film absorbing iodine is sandwiched by a cellulose acetate protective film while stretching and aligning polyvinyl alcohol. A polarizing plate composed of itself can be mentioned.

[0060]

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 evaluation items and evaluation methods of the liquid crystal aligning agents prepared in the following Examples and Comparative Examples are shown below. [Orientation of Liquid Crystal] The presence or absence of defective alignment (abnormal domains) in the liquid crystal cell when a voltage was applied to the liquid crystal display element and released was observed with a polarizing microscope, and the case where there was no abnormal domain was judged as “good”. [Measurement of Residual Voltage] A DC voltage of 10 V was applied to the liquid crystal display device at a temperature of 60 ° C. for 2 hours, and after the application of the voltage was released, the maximum voltage remaining in the liquid crystal display device was measured. [Film shaving of liquid crystal alignment film (toughness of film)] Stripe electrode made of ITO film (interval: 1 mm, ITO film thickness: 20)
00 ■), a liquid crystal aligning agent is applied to the electrode surface of the transparent electrode substrate, and the coating film is dried to form a coating having a dry film thickness of 0.05 μm, and the surface of the coating is subjected to a rubbing treatment (processing conditions:
Hair push-in length 0.6mm, roll rotation speed 500rpm
m, stage moving speed 1 cm / sec), the liquid crystal alignment film obtained was examined for the presence or absence of film scraping by rubbing.

[Synthesis Example 1] 44.8 g of 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 21.0 g of p-phenylenediamine and 3.1 g of cholesteryl 3,5-diaminobenzoate were combined with N-methyl- 2-pyrrolidone 62
0 g, and the solution was reacted at room temperature for 6 hours.
Then, the obtained reaction solution was poured into a large excess of methyl alcohol to precipitate a reaction product. Thereafter, the solid matter is separated, washed with methyl alcohol, and reduced pressure at 40 ° C. for 15 minutes.
After drying for an hour, the logarithmic viscosity (ηln) becomes 1.
21 dl / g of polyamic acid [this is referred to as “polyamic acid (A1)”. 66.0 g was obtained.

[Synthesis Example 2] 30.0 g of the polyamic acid (A1) obtained in Synthesis Example 1 was mixed with γ-butyrolactone 570.
g of pyridine, 34.4 g of pyridine and acetic anhydride.
6 g was added thereto, followed by dehydration ring closure at 110 ° C. for 3 hours. Subsequently, by precipitating, separating, washing and drying the reaction product in the same manner as in Synthesis Example 1, an imidized polymer having a logarithmic viscosity (ηln) of 1.30 dl / g [this is referred to as “polyimide (B1 ) ". 27.0 g were obtained.

Synthesis Example 3 The logarithmic viscosity (η) was the same as in Synthesis Example 1 except that 3,8.4 g of 4,4′-diaminodiphenylmethane was used instead of p-phenylenediamine.
ln) is 1.18 dl / g [this is referred to as “polyamic acid (A2)”. 79.4 g was obtained. Thereafter, the logarithmic viscosity (ηln) was 1.24 dl / in the same manner as in Synthesis Example 2 except that 30.0 g of the polyamic acid (A2) was used instead of the polyamic acid (A1).
g of polyimide [this is referred to as “polyimide (B2)”. 26.2 g were obtained.

Synthesis Example 4 39.2 g of cyclobutanetetracarboxylic dianhydride and 82.1 g of 2,2-bis [4- (4-aminophenoxy) phenyl] propane were mixed with N-
It was dissolved in 620 g of methyl-2-pyrrolidone, and the solution was reacted at room temperature for 6 hours. Next, by precipitating, separating, washing and drying the reaction product in the same manner as in Synthesis Example 1, a polyamic acid having a logarithmic viscosity (ηln) of 1.46 dl / g [this is referred to as “polyamic acid (A3) ". 115.5 g was obtained.

[Synthesis Example 5] Instead of 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,3,3a,
4,5,9b-Hexahydro-5- (tetrahydro-
2,5-dioxo-3-furanyl) -naphtho [1,2-
c] Logarithmic viscosity (ηln) was 1. in the same manner as in Synthesis Example 1 except that 60.0 g of furan-1,3-dione was used.
A polyamic acid of 05 dl / g [this is referred to as “polyamic acid (A4)”. 76.5 g was obtained. Thereafter, in the same manner as in Synthesis Example 2 except that 30.0 g of polyamic acid (A4) was used instead of polyamic acid (A1), a polyimide having a logarithmic viscosity (ηln) of 1.16 dl / g [this was referred to as “ Polyimide (B4) ". ]
26.2 g were obtained.

[Synthesis Example 6] Logarithmic viscosity (in the same manner as in Synthesis Example 1) except that 43.6 g of pyromellitic dianhydride was used instead of 2,3,5-tricarboxycyclopentylacetic acid dianhydride. η ln) is 1.66 dl / g [this is referred to as “polyamic acid (A5)”. 64.5 g were obtained.

[Synthesis Example 7] 44.8 g of 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 20.2 g of p-phenylenediamine and 4.9 g of n-dodecylamine were mixed with 620 g of N-methyl-2-pyrrolidone. And the solution was reacted at room temperature for 6 hours. Subsequently, the reaction product was precipitated, separated, washed and dried in the same manner as in Synthesis Example 1 so that the logarithmic viscosity (ηln) was 0.85 dl / g.
Polyamic acid [this is referred to as "polyamic acid (A
6) ". 63.6 g were obtained. Thereafter, polyamic acid (A6) was used instead of polyamic acid (A1) 30.
A polyimide having a logarithmic viscosity (ηln) of 0.92 dl / g [this is referred to as “polyimide (B6)” in the same manner as in Synthesis Example 2 except that 0 g was used. 25.2 g was obtained.

<Example 1> (1) Preparation of liquid crystal aligning agent: 5.0 g of polyamic acid (A1) obtained in Synthesis Example 1 and Cymel 300 (formula (I)
-1), 0.5 g of X ¹ = methyl group, X ² = compound which is an organic group represented by formula (i) (X ¹ = methyl group in formula (i)) and N-methyl-2 -A solution having a solid content of 4.0% by weight was obtained by dissolving the compound in pyrrolidone, and the solution was filtered through a filter having a pore size of 1 µm to prepare a liquid crystal aligning agent of the present invention.

(2) Production of liquid crystal display element: ITO provided on one surface of a glass substrate having a thickness of 1 mm
On a transparent conductive film made of a film, the liquid crystal aligning agent prepared as described above is applied using a coating press, and is applied at 180 ° C.
For 1 hour to form a film having a dry film thickness of 0.05 μm. The surface of the formed film was subjected to a rubbing treatment using a rubbing machine provided with a roll wound with a rayon cloth to form a liquid crystal alignment film. here,
The rubbing treatment conditions were as follows: the push-in length of the hair foot was 0.4 mm, the number of rotations of the roll was 500 rpm, and the moving speed of the stage was 1 cm /
Seconds. After the rubbing treatment, the formed liquid crystal alignment film was washed with isopropyl alcohol. The substrate on which the liquid crystal alignment film was formed as described above
An epoxy resin-based adhesive containing aluminum oxide spheres having a diameter of 17 μm was applied to the outer edge of each substrate by screen printing, and then the two rubbing directions of each liquid crystal alignment film were orthogonalized. The substrates were placed facing each other with a gap therebetween, and the outer edges were pressed together to cure the adhesive. Thereafter, the nematic liquid crystal “MLC-2004” (manufactured by Merck) is placed in the cell gap defined by the adhesive on the surfaces and the outer edges of the two substrates.
, And then the injection hole was sealed with an epoxy-based adhesive to form a liquid crystal cell. Thereafter, a polarizing plate was attached to the outer surface of the liquid crystal cell so that the polarization direction coincided with the rubbing direction of the liquid crystal alignment film formed on one surface of the substrate, thereby producing a liquid crystal display device. In the liquid crystal display device manufactured as described above, no abnormal domain was observed, and the orientation of the liquid crystal was good.
Further, the maximum residual voltage of this liquid crystal display element was as extremely small as 0.22 V. Further, a coating film was formed on the electrode surface of the transparent electrode substrate provided with the stripe electrodes in the same manner as described above, and the rubbing treatment was performed in the same manner as described above except that the bristle indentation length was 0.6 mm. When the liquid crystal alignment film was observed, no occurrence of film abrasion was observed, and it was confirmed that the liquid crystal alignment film (coating) formed by the liquid crystal alignment agent of this example had excellent toughness against abrasion force. .

<Examples 2 to 12> According to the formulation shown in Table 1 below, each of the polyamic acid and the imidized polymer of the polyamic acid [component (a)] obtained in Synthesis Examples 2 to 7 above and Table 1 Is dissolved in N-methyl-2-pyrrolidone to obtain a solution having a solid content of 4.0% by weight, and this solution is filtered through a filter having a pore size of 1 μm. Thereby, the liquid crystal alignment agent of the present invention was prepared. Using each of the liquid crystal aligning agents thus prepared, a film was formed on the substrate surface in the same manner as in Example 1, and the film was rubbed to form a liquid crystal alignment film. A liquid crystal display element was manufactured using the substrate on which the film was formed. For each of the manufactured liquid crystal display elements, the orientation of the liquid crystal was evaluated and the residual voltage was measured in the same manner as in Example 1. Further, the liquid crystal was formed on the electrode surface of the transparent electrode substrate in the same manner as in Example 1. An alignment film was formed, and whether or not the liquid crystal alignment film was scraped was observed. The results are shown in Table 1 below.

<Comparative Example> The polyamic acid (A1) obtained in Synthesis Example 1 was dissolved in N-methyl-2-pyrrolidone to obtain a solution having a solid content of 4.0% by weight. Then, a liquid crystal aligning agent for comparison was prepared by filtering with a filter of. Using the liquid crystal aligning agent thus prepared, a film is formed on the substrate surface in the same manner as in Example 1, and the film is rubbed to form a liquid crystal alignment film. A liquid crystal display device was manufactured using the formed substrate. With respect to the manufactured liquid crystal display element, the orientation of the liquid crystal was evaluated and the residual voltage was measured in the same manner as in Example 1. Further, as in Example 1, the liquid crystal alignment film was formed on the electrode surface of the transparent electrode substrate. Was formed, and whether or not the liquid crystal alignment film was scraped was observed. The results are shown in Table 1 below.
Shown in

[0072]

[Table 1] * 1: In the above formula (I-1), X ¹ = methyl group, X
² = a compound that is an organic group represented by the formula (i) (X ¹ = hydrogen atom in the formula (i)) * 2: In the above formula (I-1), X ¹ = hydrogen atom, X
² = Compound which is an organic group represented by a hydrogen atom * 3: In the above formula (I-1), X ¹ = methyl group or butyl group, X ² = Formula (i) (wherein X ¹ = A compound which is an organic group represented by a methyl group or a butyl group * 4: In the above formula (I-2), X ¹ = methyl group or ethyl group, X ² = formula (i) (X in formula (i) ⁽¹ = methyl group or ethyl group) * 5: Compound of the above formula (I-3), wherein X ¹ is an organic group of a butyl group * 6: Formula (I-4) )), X ¹ = methyl group, X
² = a compound which is an organic group represented by the formula (i) (wherein X ¹ = methyl group in the formula (i))

[0073]

According to the liquid crystal aligning agent of the present invention, it is possible to form a resin film on the transparent electrode substrate which does not cause film shaving even when rubbing is performed. Further, a liquid crystal alignment film formed by performing a rubbing process on the surface of the resin film, in a liquid crystal display element configured with the same,
Excellent display performance due to the low residual voltage after the release of the voltage application, that is, display performance with high contrast and little afterimage is generated on the display screen. The liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention can be used not only for TN liquid crystal display elements and STN liquid crystal display elements, but also for SH (Super Homeotropic).
Mold, IPS (In-Plane Switching)
Mold, OCB (Optically Compensat)
The present invention can be suitably used for forming various liquid crystal display elements such as an ed Birefringence type liquid crystal display element and a ferroelectric liquid crystal display element. In addition, a liquid crystal display device including the liquid crystal alignment film has excellent liquid crystal alignment and reliability, and can be effectively used for various devices. For example, a desk calculator, a wristwatch, a clock, a counting display,
It can be suitably used as a display device such as a word processor, a personal computer, and a liquid crystal television.

Continuation of the front page (72) Inventor Yasuo Matsuki 2-11-24 Tsukiji, Chuo-ku, Tokyo Inside Nippon Gosei Rubber Co., Ltd.

Claims (1)

[Claims] 1. A polymer selected from the group consisting of (a) a polyamic acid and an imidized polymer of a polyamic acid, and (b) a compound represented by the following formula (I): (Wherein, X represents an alkyl group or a hydrogen atom). A liquid crystal alignment agent comprising a compound having an organic group represented by the formula: