JPH0876128A - Liquid crystal orienting agent - Google Patents

Abstract

PURPOSE: To provide a liquid crystal orienting agent which realizes a liquid crystal cell with little afterimages and having a high voltage holding rate. CONSTITUTION: This agent consists of (a) 100 pts.wt. of at least one polymer material selected from among polymers obtd. by the reaction of tetracarboxylic acid dianhydride and diamine compd., imidized polymers of these, and isoimidized polymers of these, and (b) 5×10<-5> to 5×10<-2> pts.wt. of at least one compd. selected from among compds. containing one carboxylic acid group in the molecule, compds. having one carboxylic acid anhydride group in the molecule, and compds. containing one tertiary amine group in the molecule.

Description

Detailed Description of the Invention

FIELD OF THE INVENTION The present invention relates to a liquid crystal aligning agent.
More specifically, the present invention relates to a liquid crystal aligning agent that gives a liquid crystal aligning film having a small afterimage and a high voltage holding ratio.

2. Description of the Related Art Conventionally, polyimide, polyamide, polyester and the like have been used as liquid crystal alignment films for liquid crystal display devices. In particular, polyimide is used for many liquid crystal alignment films because it has excellent thermal stability. For example, in a substrate with a transparent electrode having a liquid crystal alignment film made of polyimide or the like, a nematic liquid crystal having a positive dielectric anisotropy has a sandwich structure, and the long axis of liquid crystal molecules is 90% between the substrates.
TN or S that can be twisted continuously up to 270 degrees
TN type liquid crystal display element (hereinafter referred to as "TN, STN type display element")
Say. )It has been known. The liquid crystal alignment in the TN and STN type display elements is formed by a rubbing-treated liquid crystal alignment film, but ionic charges are adsorbed to the liquid crystal alignment film when a voltage is applied, and an afterimage occurs when the voltage is erased. Therefore, there is a problem that sufficient contrast cannot be obtained. Further, when the liquid crystal display element is driven in a certain frame cycle, a low voltage holding ratio causes a reduction in contrast.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid crystal aligning agent for a liquid crystal display device which has a short afterimage erasing time at the time of voltage erasing of a liquid crystal cell and has a high voltage holding ratio.

[0002]

The above objects of the present invention are as follows.
(A) Polyamic acid obtained by reacting tetracarboxylic dianhydride and diamine compound (hereinafter referred to as “polymer A”)
Say. ) Or 100 parts by weight of at least one polymer selected from polymers obtained by dehydration ring closure of polymer A (hereinafter referred to as “polymer B”), and (b) containing one carboxylic acid group in the molecule. At least one compound selected from the group consisting of compounds, compounds containing one carboxylic acid anhydride group in the molecule, and compounds containing one tertiary amine group in the molecule (hereinafter referred to as “compound C”) 5. X 10 ^{-5 to} 5 x
It is achieved by a liquid crystal aligning agent characterized by containing 10 ^-2 parts by weight.

The details of the present invention will be described below. Examples of the tetracarboxylic dianhydride used when synthesizing the polymer A in the present invention include butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, and 1,2,3,4-cyclobutanetetracarboxylic dianhydride. , 3,4-Cyclopentanetetracarboxylic acid dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, tetracyclo [6,2,1,
1,0 ^2,7 ] dodeca-4,5,9,10-tetracarboxylic dianhydride, 3,5,6-tricarboxynorbornane-2-acetic acid dianhydride, 2,3,4,5-tetrahydrofuran Tetracarboxylic dianhydride, 1,3,3a, 4
5,9b-hexahydro-5-tetrahydro-2,5-
Dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-
1,2-dicarboxylic acid dianhydride, bicyclo [2,2,2]
2] -Octo-7-ene-2,3,5,6-tetracarboxylic dianhydride or other aliphatic or alicyclic tetracarboxylic dianhydride; pyromellitic dianhydride, 3,3 ′,
4,4'-benzophenone tetracarboxylic acid dianhydride,
3,3 ', 4,4'-biphenylsulfone tetracarboxylic acid dianhydride, 1,4,5,8-naphthalene tetracarboxylic acid dianhydride, 2,3,6,7-naphthalene tetracarboxylic acid dianhydride , 3,3 ', 4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3', 4,4 '
-Dimethyldiphenylsilane tetracarboxylic dianhydride, 3,3 ', 4,4'-tetraphenylsilane tetracarboxylic dianhydride, 1,2,3,4-furan tetracarboxylic dianhydride, 4,4 ′ -Bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,
4'-bis (3,4-dicarboxyphenoxy) diphenyl sulfone 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-
Aromatic aromatic compounds such as bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4'-diphenylether dianhydride, bis (triphenylphthalic acid) -4,4'-diphenylmethane dianhydride A tetracarboxylic dianhydride can be mentioned.

Among these, butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, tetracyclo [6,2] , 1, 1, 0
^2,7 ] Dodeca-4,5,9,10-tetracarboxylic dianhydride, 5- (2,5-dioxotetrahydrofural)
-3-Methyl-3-cyclohexene-1,2-dicarboxylic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5-tetrahydro-2,5-dioxo-3-furanyl) -naphtho [ 1,2-c] -furan-1,3-dione, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′,
4,4'-biphenylsulfone tetracarboxylic dianhydride, 3,3 ', 4,4'-perfluoroisopropylidene diphthalic dianhydride, 3,3', 4,4'-biphenyl tetracarboxylic dianhydride Anhydrous and the like are preferable. These can be used alone or in combination of two or more.

Examples of the diamine compound used when synthesizing the polymer A in the present invention include p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4 , 4'-diaminodiphenyl sulfide,
4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminobenzanilide, 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, bis [4- (4-aminophenoxy) phenyl] sulfone, 1,4- Bis (4-
Aminophenoxy) benzene, 4,4 '-(p-phenylenediisopropylidene) bisaniline, 4,4'-
(M-phenylenediisopropylidene) bisaniline,
1,3-bis (4-aminophenoxy) benzene, 1,
3-bis (3-aminophenoxy) benzene, 9,9-
Bis (4-aminophenyl) -10-hydroanthracene, 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- Aromatic diamines such as 4,4′-diaminobiphenyl; Aromatic diamines having a hetero atom such as diaminotetraphenylthiophene; 1,1-Metaxylylenediamine, 1,2-ethylenediamine, 1,3-propanediamine, tetra Methylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 1,4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoin. Daniylene methylenediamine, g Cyclo [6,2,1,0 ^2.7] - undecylenate range methyl diamine, 4,4'-methylenebis aliphatic or alicyclic diamines such as (cyclohexylamine);

The following formula: H ₂ N- (CH ₂ ) p-SiR ₂ -(-O-SiR
_{2 -) q- (CH 2)} p-NH 2 ( wherein, R is as aryl groups such as a cycloalkyl group or a phenyl group such as an alkyl group, a cyclohexyl group selected from methyl group, ethyl group and propyl group A C1-12 hydrocarbon group, p is 1 to 3, and q is 1 to 20).

Of these, p-phenylenediamine,
4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9-bis (4-aminophenyl) fluorene, 2,2 -Bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 '-(p-phenylenediisopropylidene) bisaniline, 4,4 ′-(M-Phenylenediisopropylidene) bisaniline and the like are preferable. These can be used alone or in combination of two or more.

The ratio of the tetracarboxylic dianhydride to the diamine compound used is such that the acid anhydride group of the tetracarboxylic dianhydride is 0.2 per 1 equivalent of the amino group in the diamine compound.
~ 2 equivalents are preferred, and more preferably 0.3 ~
It is 1.4 equivalents. Further, at the time of synthesizing the polymer A, it is also possible to add an acid anhydride, a monoamine compound or the like for the purpose of adjusting the molecular weight of the polymer, improving the coating property on a substrate, and the like. It can be used in the present invention. Here, examples of the acid anhydride include maleic anhydride, phthalic anhydride, and itaconic anhydride. Examples of monoamine compounds include 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-eicosylamine, etc. Can be mentioned.

The polymer A in the present invention is obtained by reacting a tetracarboxylic dianhydride and a diamine compound.
Such a reaction is carried out in an organic solvent at a temperature of generally 0 to 150 ° C, preferably 0 to 100 ° C.

The organic solvent used in the reaction is one capable of dissolving the tetracarboxylic dianhydride, the diamine compound and the polymer A produced by the reaction, for example, γ-butyrolactone, N-methyl-2-pyrrolidone, N , N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, tetramethylurea, hexamethylphosphortriamide, and other aprotic polar solvents; m-cresol, xylenol, phenol, halogenated phenols, and other phenolic solvents. Can be mentioned.

In these organic solvents, polymer A which produces alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, etc., which are poor solvents for polymer A, is deposited. It can be used together to the extent that it does not. Examples of such a poor solvent include methyl alcohol,
Ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, Diethyl oxalate, diethyl malonate, diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-
Propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether,
Ethylene glycol-n-hexyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethylene Glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol-n-propyl ether acetate, ethylene glycol-i-propyl ether acetate, ethylene glycol-n-butyl ether acetate, ethylene Glycol-n-hexyl ether acetate, 4-hydroxy-4-methyl-2-pentanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethoxy Ethyl acetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate,
Ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane. , Heptane, octane, benzene, toluene, xylene and the like.

The amount of the organic solvent used is usually preferably such that the total amount of the tetracarboxylic dianhydride and the diamine is 0.1 to 30% by weight based on the total amount of the reaction solution.

The polymer B in the present invention can be obtained by heating the above polymer A or by subjecting the polymer A to a dehydration ring-closing reaction in the presence of a dehydrating agent and a dehydration ring-closing catalyst. Polymer B
Is usually polyimide or polyisoimide. When the dehydration ring closure reaction is caused by heating, the reaction temperature is usually 60 to 200 ° C, preferably 100 to 170 ° C.
If the reaction temperature is less than 60 ° C, the reaction progresses slowly,
If it exceeds 0 ° C, the molecular weight of the polymer B may be significantly reduced. Further, the reaction in the case of the dehydration ring-closing reaction in the presence of the dehydrating agent and the dehydration ring-closing catalyst can be carried out in the above-mentioned organic solvent. The reaction temperature in this case is usually 0 to 18
The temperature is 0 ° C, preferably 60 to 150 ° C. As the dehydrating agent, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. Further, as the dehydration ring-closing catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, triethylamine and the like can be used. The amount of the dehydrating agent used is the repeating unit 1 of the polymer A.
It is preferably from 1.5 to 20 mol per mol. Further, the amount of the dehydration ring-closing catalyst used is preferably 0.5 to 10 mol per 1 mol of the dehydrating agent used. Intrinsic viscosity of polymer A and / or polymer B thus obtained [η _inh : ln (η rel / C), C = 0.5 g / d
1, 30 ° C., in N-methyl-2-pyrrolidone, the same applies hereinafter] is usually 0.05 to 10 dl / g, preferably 0.05 to 5 dl / g.

The polymer A and / or polymer B solution obtained by the reaction is usually put in a large amount of a poor solvent to precipitate the polymer, and the precipitate is dried under reduced pressure to recover the polymer. Good. Further, the polymer can be purified by performing the step of dissolving the recovered polymer again in the organic solvent and then putting it in the poor solvent to cause precipitation once or several times.

The liquid crystal aligning agent of the present invention usually contains 1 to 10% by weight of the polymer A and / or the polymer B in an organic solvent. As the organic solvent used here, the above-mentioned solvents that can be used for polymerization of the polymer can be used. Further, the poor solvent described as usable for the above-mentioned polymerization can also be appropriately selected and used within a range in which the polymer does not precipitate. The organic solvent is selected in consideration of solution viscosity, volatility, influence on the environment, and the like. A liquid crystal aligning agent containing a polymer is applied to a substrate by a printing method, a spin coating method or the like, and dried to form an alignment film. At this time, if the polymer concentration is less than 1% by weight, the film thickness becomes too thin, while if it exceeds 10% by weight, there is a problem that the film thickness becomes too large, and the solution viscosity becomes large and printing becomes difficult. Also, the coating characteristics are deteriorated even by the spin coating method.

In the compound C used in the present invention, the compound containing one carboxylic acid group in the molecule is
Acetic acid, propionic acid, trifluoroacetic acid, benzoic acid, n
-Butyric acid, isobutyric acid, n-caproic acid, isocaproic acid,
Formic acid, cyclopropanecarboxylic acid, cyclobutanecarboxylic acid, cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, acrylic acid, methacrylic acid and the like can be mentioned.

Compounds containing one carboxylic acid group in the molecule include acetic anhydride, propionic anhydride, trifluoroacetic anhydride, phthalic anhydride, n-butyric anhydride, isobutyric anhydride, n-caproic anhydride. Isocaproic anhydride, cyclopropanecarboxylic anhydride, cyclobutanecarboxylic anhydride, cyclopentanecarboxylic anhydride, cyclohexanecarboxylic anhydride, maleic anhydride, itaconic anhydride, citraconic anhydride, mesaconic anhydride, muconic anhydride,
Examples thereof include fumaric acid anhydride and succinic anhydride.

Examples of compounds having one tertiary amine group in the molecule include pyridine, collidine, lutidine, quinoline, isoquinoline, triethylamine, tripropylamine, trimethylamine, dimethylethylamine, methyldiethylamine, dimethylethanolamine, methyldiethanolamine. , Ethyldiethanolamine, triethanolamine, piperidine, N-methylpiperidine, N-ethylpiperidine, N-methylpyrrolidine, N
-Ethylpyrrolidine, N-methylmorpholine, 1,8-
Diazabicyclo- [5.4.0] -7-undecene,
1,5-diazabicyclo- [4.3.0] -5-nonane and the like can be mentioned.

Of these, acetic acid, propionic acid, trifluoroacetic acid, acetic anhydride, propionic anhydride, trifluoroacetic anhydride, pyridine, collidine, lutidine, quinoline, isoquinoline, triethylamine, tripropylamine and the like are particularly preferable. The ratio of the compound C to the polymer A and / or the polymer B is 5 × 10 ⁻⁵ to 5 × 10 with respect to 100 parts by weight of the polymer A and / or the polymer B.
^-2 parts by weight, preferably 5 × 10 ^{−5 to} 5 × 10 ⁻³ parts by weight. If the proportion of compound C is less than 5 × 10 ⁻⁵ , the afterimage improving effect is small, and the proportion of compound C is 5 × 10 ^−2.
If it exceeds the weight part, the film forming property of the liquid crystal aligning agent is disturbed.

The liquid crystal aligning agent of the present invention comprises polymer A and / or
Alternatively, a functional silane-containing compound may be contained for the purpose of further improving the adhesiveness between the polymer B and the substrate. Examples of such a functional silane-containing compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane and N- (2-amino Ethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3 -Aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 1
0-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-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane and the like can be mentioned. −
It is also possible to use a reaction product of a tetracarboxylic dianhydride and an amino group-containing silane compound described in JP-A-291922.

The 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. First, the liquid crystal aligning agent of the present invention is applied to the transparent conductive film side of the substrate provided with the transparent conductive film, and the liquid crystal aligning agent of 80 to 200 ° C.
Preferably, the coating film is formed by heating at a temperature of 120 to 200 ° C. This coating film usually has a thickness of 0.001 to 1 μm, preferably 0.005 to 0.5 μm.

The coating film formed as described above is made into a liquid crystal alignment film by rubbing with a roll around which a cloth made of synthetic fiber such as nylon is wound. As the substrate, a transparent substrate made of glass such as float glass or soda glass, plastic film such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone or polycarbonate can be used.

As the transparent conductive film, SnO _{2 is used.}
NESA film made of I, and I made of In ₂ O ₃ —SnO _2.
A TO film or the like can be used, and a photo-etching method, a method using a mask in advance, or the like is used for patterning these transparent conductive films. When 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 or a functional titanium compound is previously formed on the substrate and the transparent conductive film. It can also be applied. The substrates on which the liquid crystal alignment film is formed are made to face each other so that the rubbing directions of the liquid crystal alignment films are orthogonal or anti-parallel, and the peripheral portion between the substrates is sealed with a sealant, and the liquid crystal is filled and filled. A liquid crystal display element is obtained by sealing the holes and sticking on both sides so that the polarization directions are the same or orthogonal to the rubbing direction of the liquid crystal alignment film of the substrate.

As the sealant, for example, a curing agent and an epoxy resin containing aluminum oxide spheres as a spacer can be used. The liquid crystal is preferably a nematic liquid crystal, a smectic liquid crystal, and among them, a liquid crystal forming a nematic liquid crystal, for example, a Schiff base liquid crystal, an azoxy liquid crystal, a biphenyl liquid crystal, a phenylcyclohexane liquid crystal, an ester liquid crystal, a terphenyl liquid crystal. Liquid crystals, biphenylcyclohexane-based liquid crystals, pyrimidine-based liquid crystals, dioxane-based liquid crystals, bicyclooctane-based liquid crystals, cubane-based liquid crystals and the like are used. In addition to these liquid crystals, for example, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonaate and cholesteryl carbonate, and trade names C-15 and CB-
It is also possible to add and use a chiral agent such as that sold as No. 15 (manufactured by Merck). Furthermore, p
Ferroelectric liquid crystals such as-decyloxybenzylidene-p-amino-2-methylbutyl cinnamate can also be used.

As a polarizing plate used on the outside of the liquid crystal display element, while polyvinyl alcohol is stretched and aligned,
Examples thereof include a polarizing plate in which a polarizing film called an H film absorbing iodine is sandwiched between cellulose acetate protective films, or a polarizing plate composed of the H film itself.

[0026]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The liquid crystal display element produced by using the liquid crystal aligning agent of the present invention was evaluated by the following method. Orientation evaluation of liquid crystal display device: The presence or absence of an abnormal domain in the liquid crystal display device when the voltage was turned on and off was observed with a polarizing microscope, and when there was no abnormal domain, it was judged as good. The voltage holding ratio of the liquid crystal display device: It was evaluated by applying a voltage of 5 V to the liquid crystal display device installed in a constant temperature bath of 60 ° C., turning off the voltage, and measuring the voltage holding ratio after 16.7 msec. Afterimage erasing time: A DC voltage of 15 V was applied to the liquid crystal display element for 1 hour, the voltage was turned off, and the time until the afterimage was erased was measured visually.

Synthesis Example 1 44.8 g of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride and 21.6 g of p-phenylenediamine
Was dissolved in 988 g of N-methyl-2-pyrrolidone and reacted at room temperature for 6 hours. Then, the reaction solution was poured into a large excess of methanol to precipitate the polyamic acid. Then, it was washed with methanol and dried under reduced pressure at 40 ° C. for 15 hours to obtain a polymer (A-1) having an intrinsic viscosity of 1.44 dl / g.
60.2 g was obtained. When 1 g of this polymer (A-1) was dissolved in 9 g of N-methyl-2-pyrrolidone and the content of compound C was measured by gas chromatography, a peak corresponding to compound C was not detected. The measurement sensitivity is 5 × 10 ⁻⁵ parts by weight with respect to 100 parts by weight of the polymer.

Synthesis Example 2 30.0 g of the polymer (A-1) obtained in Synthesis Example 1 was added to 57
Dissolve in 0 g of γ-butyrolactone to give pyridine 21.6
g and 16.74 g of acetic anhydride were added, and an imidization reaction was carried out at 120 ° C. for 3 hours. Then, the polymer was precipitated in the same manner as in Synthesis Example 1 to obtain 24.0 g of a polymer (B-1) having an intrinsic viscosity of 1.35 dl / g. This polymer (B-1) 1
g was dissolved in 9 g of N-methyl-2-pyrrolidone, and the content of the compound C was measured by gas chromatography in the same manner as in Synthesis Example 1. As a result, peaks corresponding to these were not detected.

Synthesis Example 3 A polymer (A-2) was obtained in the same manner as in Synthesis Example 1 except that the diamine was changed to 39.6 g of 4,4'-diaminodiphenylmethane in Synthesis Example 1, and this polymer ( A-
2) was used to carry out an imidization reaction in the same manner as in Synthesis Example 2 to obtain a polymer (B-2) 2 having an intrinsic viscosity of 1.16 dl / g.
2.2 g was obtained. This polymer (B-2) was analyzed in the same manner as in Synthesis Example 2, but no peak corresponding to compound C was detected.

Synthetic Example 4 Intrinsic viscosity 1.26 dl / g in the same manner as in Synthetic Example 1 except that the tetracarboxylic dianhydride was changed to 39.22 g of cyclobutanetetracarboxylic dianhydride.
50.5 g of the polymer (A-3) was obtained. This polymer (A
-3) was analyzed for compound C in the same manner as in Synthesis Example 1, but peaks corresponding to these were not detected.

Synthesis Example 5 In Synthesis Example 1, tetracarboxylic acid dianhydride was added to 1,
3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione 60.0 g except that A polymer (A-4) was obtained in the same manner as in Synthesis Example 1,
Further, using this polymer (A-4), an imidization reaction was carried out in the same manner as in Synthesis Example 2 to obtain 22.2 g of a polymer (B-4) having an intrinsic viscosity of 1.16 dl / g. This polymer (B-
4) was analyzed by gas chromatography in the same manner as in Synthesis Example 2, but no peak corresponding to compound C was detected.

Synthesis Example 6 A polymer having an intrinsic viscosity of 1.66 dl / g was prepared in the same manner as in Synthesis Example 1 except that 43.6 g of pyromellitic dianhydride was used as the tetracarboxylic acid dianhydride. A-
5) Obtained 60.5 g. This polymer (A-5) was analyzed by gas chromatography in the same manner as in Synthesis Example 1, but no peak corresponding to compound C was detected.

Example 1 100 g of the polymer (A-1) obtained in Synthesis Example 1 and 0.001 g of pyridine were dissolved in N-methyl-2-pyrrolidone to obtain a solution having a solid content of 4% by weight. The solution was filtered with a filter having a pore size of 1 μm to prepare a liquid crystal aligning agent.
This solution was applied to ITO using a printing machine for coating liquid crystal alignment film.
Coating on the transparent electrode surface on a glass substrate with a transparent electrode made of a film, dried at 180 ° C for 1 hour, and dried film thickness 0.05μ
m coating film was formed. By a rubbing machine having a roll in which a cloth made of rayon is wrapped around this coating film, the rotation speed of the roll is 500 rpm, the moving speed of the stage is 1 cm /
The rubbing treatment was performed at a pressing length of 0.6 mm for 2 seconds. Next, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 17 μm is screen-printed on each outer edge of the pair of rubbed substrates having the liquid crystal alignment film, and then the pair of substrates are opposed to each other. As described above, and further, the rubbing directions were overlapped with each other and pressure-bonded to cure the adhesive. Then, a nematic type liquid crystal (Merck & Co., Z
After filling LI-5080), the liquid crystal injection port is sealed with an epoxy adhesive, polarizing plates are provided on both outer sides of the substrate, and the polarization direction of the polarizing plate matches the rubbing direction of the liquid crystal alignment film of each substrate. Then, the liquid crystal display device was manufactured by laminating as described above, and the orientation, the voltage holding ratio and the afterimage erasing time were evaluated. The results are shown in Table 1.

Examples 2 to 21 Example 1 was repeated except that the liquid crystal aligning agent was prepared by using the polymer A or the polymer B obtained in Synthesis Examples 2 to 6 and the compound C shown in the table. A liquid crystal display device was prepared and evaluated in the same manner as in. The results are shown in Tables 1 and 2.

Comparative Example 1 The polymer (A-1) obtained in Synthesis Example 1 was dissolved in N-methyl-2-pyrrolidone to prepare a liquid crystal aligning agent in the same manner as in Example 1 except that pyridine was not added. The liquid crystal alignment film and the liquid crystal display device were prepared using the prepared liquid crystal and evaluated. Table 2 shows the results.

Comparative Example 2 The polymer (B-1) obtained in Synthesis Example 2 was dissolved in N-methyl-2-pyrrolidone to prepare a liquid crystal aligning agent in the same manner as in Example 1 except that pyridine was not added. The liquid crystal alignment film and the liquid crystal display device were prepared using the prepared liquid crystal and evaluated. Table 2 shows the results.

Comparative Example 3 N-methyl-2 was prepared in the same manner as in Example 1 except that pyridine was not added to the polymer (A-5) obtained in Synthesis Example 6.
-Dissolved in pyrrolidone to prepare a liquid crystal aligning agent, and using this, a liquid crystal aligning film and a liquid crystal display device were prepared and evaluated. Table 2 shows the results.

Comparative Example 4 A liquid crystal display device was prepared and evaluated in the same manner as in Example 1 except that 100 g of the polymer (A-5) obtained in Synthesis Example 6 and 1 g of pyridine were used. Table 2 shows the results.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

When the liquid crystal aligning agent of the present invention is used, the afterimage erasing time when the voltage is erased after the voltage is applied to the liquid crystal display element is short, the voltage holding ratio is high, and the liquid crystal orientation is good. An excellent liquid crystal alignment film can be obtained. Further, a liquid crystal display device having a liquid crystal alignment film formed by using the liquid crystal aligning agent of the present invention can be selected by selecting a liquid crystal to be used, and thus SH (Super
It can also be suitably used for homeotropic), ferroelectric and antiferroelectric liquid crystal display devices. Furthermore, a liquid crystal display device having an alignment film formed by using the liquid crystal aligning agent of the present invention is excellent in liquid crystal alignment and reliability and can be effectively used in various devices. For example, desktop calculators, wrist watches, clocks, and coefficients. It is used for display devices such as display boards, word processors, personal computers, and liquid crystal televisions.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Tadahiko Udagawa 2-11-24 Tsukiji, Chuo-ku, Tokyo Within Nippon Synthetic Rubber Co., Ltd. (72) Inventor Yasushi Matsuki 2-11-24 Tsukiji, Chuo-ku, Tokyo Within Nippon Synthetic Rubber Co., Ltd.

Claims (1)

[Claims] 1. 100 parts by weight of at least one polymer selected from (a) a polyamic acid obtained by reacting a tetracarboxylic dianhydride and a diamine compound or a polymer obtained by dehydration ring closure of the polymer, and (B) a compound containing one carboxylic acid group in the molecule, a compound containing one carboxylic acid anhydride group in the molecule and one in the molecule
A liquid crystal aligning agent, characterized by containing 5 × 10 ^{−5 to} 5 × 10 ⁻² parts by weight of at least one compound selected from compounds each having a tertiary amine group. [0001]