JP3201172B2 - Liquid crystal alignment agent - Google Patents

Description

DETAILED DESCRIPTION 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 which gives a liquid crystal alignment film having a low afterimage and a high voltage holding ratio.

2. Description of the Related Art Conventionally, polyimide, polyamide, polyester and the like have been used as a liquid crystal alignment film for a liquid crystal display device. Particularly, polyimide is used for many liquid crystal alignment films because of its excellent thermal stability and the like. For example, on 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 is formed in a sandwich structure, and the major axis of the liquid crystal molecules is 90
TN or S that can be twisted continuously up to 270 degrees
TN type liquid crystal display device (hereinafter referred to as "TN, STN type display device")
That. )It has been known. The alignment of the liquid crystal in the TN or STN type display element is formed by a rubbed 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 a sufficient contrast cannot be obtained. When the liquid crystal display element is driven at a certain fixed frame period, a low voltage holding ratio causes a decrease 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 having a short afterimage erasing time when erasing a voltage of a liquid crystal cell and having a high voltage holding ratio.

[0002]

The above objects of the present invention are as follows.
(A) a tetracarboxylic dianhydride and a diamine compound
Polyamic acid obtained by the reaction (hereinafter referred to as “polymer A”)
That. ) By dehydration and ring closure (hereinafter referred to as “polymer B”)
Say. ) 100 parts by weight, and (b) a compound containing one carboxylic acid group in the molecule, one tertiary within one compound containing carboxylic acid anhydride groups and molecular in the molecule
At least one compound selected from compounds containing an amino group (hereinafter, referred to as “compound C”) in a range of 5 × 10 ^{−5 to} 5 × 5;
A liquid crystal aligning agent characterized by containing × 10 ^-2 parts by weight.
And a liquid crystal alignment film obtained from the liquid crystal alignment agent.
This is achieved by a liquid crystal display element characterized by the following.

The details of the present invention will be described below. The tetracarboxylic dianhydride used when synthesizing the polymer A in the present invention includes, for example, butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2 , 3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic 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 dianhydride, bicyclo [2,2,
2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride or other aliphatic or alicyclic tetracarboxylic 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'-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) phenyl phosphine oxide dianhydride , P-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-
Aromatics such as bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4'-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4'-diphenylmethane dianhydride Tetracarboxylic dianhydride can be mentioned.

Among these, butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic 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 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'-biphenylsulfonetetracarboxylic dianhydride, 3,3 ', 4,4'-perfluoroisopropylidene diphthalic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic dianhydride Anhydrides and the like are preferred. These can be used alone or in combination of two or more.

The diamine compound used for synthesizing the polymer A in the present invention includes, for example, p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, , 4'-diaminodiphenyl sulfide,
4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylether, 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- Screw (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-methaxylylenediamine, 1,2-ethylenediamine, 1,3-propanediamine, tetra Methylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 1,4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoin Danylene dimethylene diamine, 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 And p represents 1 to 3 and q represents 1 to 20).

[0007] 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 preferred. These can be used alone or in combination of two or more.

The ratio of the tetracarboxylic dianhydride to the diamine compound is such that the acid anhydride group of the tetracarboxylic dianhydride is 0.2 to 1 equivalent of the amino group in the diamine compound.
To 2 equivalents, more preferably 0.3 to
1.4 equivalents. Further, at the time of synthesis of the polymer A, it is also possible to add an acid anhydride, a monoamine compound, or the like for the purpose of controlling the molecular weight of the polymer, improving coatability 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 the monoamine compound 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 with a diamine compound.
This reaction is carried out in an organic solvent at a temperature of usually 0 to 150 ° C, preferably 0 to 100 ° C.

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

In these organic solvents, polymer A which forms a poor solvent for polymer A such as alcohols, ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons is deposited. They can be used together to the extent that they do not. Such poor solvents include, for example, 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 tetracarboxylic dianhydride and diamine is 0.1 to 30% by weight based on the total amount of the reaction solution.

The polymer B in the present invention is obtained by heating the above-mentioned polymer A or by subjecting it to a dehydration ring-closing reaction in the presence of a dehydrating agent and a dehydration ring-closing catalyst. Polymer B
Is usually a polyimide or polyisoimide. The reaction temperature when the dehydration ring-closing reaction is caused by heating is usually 60 to 200 ° C, preferably 100 to 170 ° C.
If the reaction temperature is lower than 60 ° C., the progress of the reaction is delayed, and
When the temperature exceeds 0 ° C., the molecular weight of the polymer B may be greatly reduced. The reaction in the case of performing a dehydration ring-closing reaction in the presence of a dehydrating agent and a dehydration ring-closing catalyst can be performed in the above-mentioned organic solvent. The reaction temperature in this case is usually from 0 to 18
0 ° C., preferably 60 to 150 ° C. Acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used as the dehydrating agent. As the dehydration ring-closing catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, and triethylamine can be used. The amount of the dehydrating agent used is the repeating unit 1 of the polymer A.
The amount is preferably 1.5 to 20 moles per mole. The amount of the dehydration ring-closing catalyst used is preferably 0.5 to 10 mol per 1 mol of the dehydrating agent used. The intrinsic viscosity [η _inh : ln (ηrel / C), C = 0.5 g / d of the polymer A and / or the polymer B thus obtained.
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 placed 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. In addition, the polymer can be purified by dissolving the recovered polymer in an organic solvent again, and then putting it in a poor solvent to perform precipitation once or several times.

[0015] The liquid crystal aligning agent of the present invention is polymerized in an organic solvent.
It usually contains 1 to 10% by weight of a body . As the organic solvent used here, the above-mentioned solvents that can be used for the polymerization of the polymer A and the polymer B can be used. Also,
The poor solvent described as usable in the polymerization can be appropriately selected and used within a range in which the polymer does not precipitate. The organic solvent is
The selection is made in consideration of the solution viscosity, volatility, influence on the environment, and the like. A liquid crystal alignment agent containing a polymer is printed on a substrate by a printing method,
It is applied by a spin coating method or the like and dried to form a liquid crystal alignment film. At this time, if the polymer concentration is less than 1% by weight, the film thickness becomes too thin. On the other hand, if it exceeds 10% by weight, the film thickness becomes too large, and the solution viscosity becomes large and printing becomes difficult. In addition, the coating characteristics are also deteriorated by the spin coating method.

In the compound C used in the present invention, the compound having one carboxylic acid group in the molecule includes:
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 having 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 anhydride and succinic anhydride.

Compounds containing one tertiary amino 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 preferred. The proportion of the compounds C for polymer B, 5 × 10 ^-5 ~5 respect polymer B 100 parts by weight
× 10 ^-2 parts by weight, preferably 5 × 10 ^{-5 to} 5 × 10 ^-3 parts by weight. When the proportion of the compound C is less than 5 × 10 ⁻⁵ parts by weight, the effect of improving the afterimage is small, and when the proportion of the compound C exceeds 5 × 10 ⁻² parts by weight, the film formability of the liquid crystal aligning agent is disturbed. Would.

The liquid crystal aligning agent of the present invention may contain a functional silane-containing compound for the purpose of further improving the adhesiveness between the polymer B and the substrate. Examples of such functional silane-containing compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, 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, 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)
Examples thereof include -3-aminopropyltriethoxysilane and the like. Further, a reaction product of a tetracarboxylic dianhydride and an amino group-containing silane compound described in JP-A-63-291922 can also be used.

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. 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,
The coating is preferably formed by heating at a temperature of 120 to 200 ° C. This coating film has a thickness of usually 0.001 to 1 μm, preferably 0.005 to 0.5 μm.

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

Further, SnO ₂ is used as the transparent conductive film.
NESA film made of, consists of In ₂ O ₃ -SnO ₂ I
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. In applying the liquid crystal aligning agent, a functional silane-containing compound or a functional titanium compound is previously coated on the substrate and the transparent conductive film in order to further improve the adhesion between the substrate and the transparent conductive film. It can also be applied. The two substrates on which the liquid crystal alignment film is formed face the liquid crystal alignment film so that the rubbing directions are orthogonal or antiparallel, and the peripheral portion between the substrates is sealed with a sealant, filled with liquid crystal, and filled. The liquid crystal display device is obtained by sealing the holes to form a liquid crystal display device, and laminating both surfaces of the liquid crystal display device such that the polarization directions thereof coincide with or perpendicular to the rubbing direction of the liquid crystal alignment film of the substrate.

As the sealant, for example, an epoxy resin containing a hardening agent and aluminum oxide spheres as a spacer can be used. As the liquid crystal, a nematic liquid crystal, a smectic liquid crystal, and among them, a liquid crystal that forms a nematic liquid crystal are preferable. 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, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonaate, and cholesteryl carbonate, and trade names C-15 and CB-
15 (manufactured by Merck & Co.) and the like can be used by adding a chiral agent or the like. Furthermore, p
Ferroelectric liquid crystals such as -decyloxybenzylidene-p-amino-2-methylbutylcinnamate can also be used.

As a polarizing plate used outside the liquid crystal display element, polyvinyl alcohol is stretched and oriented.
Examples include a polarizing plate in which a polarizing film called an H film that has absorbed iodine is sandwiched by a cellulose acetate protective film and a polarizing plate composed of the H film itself.

[0026]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In addition, the following method evaluated the liquid crystal display element produced using the liquid crystal aligning agent of this invention. Evaluation of the orientation of the liquid crystal display element: The presence or absence of abnormal domains in the liquid crystal display element when the voltage was turned on / off was observed with a polarizing microscope. Voltage holding ratio of liquid crystal display device: After applying a voltage of 5 V to a liquid crystal display device installed in a thermostat at 60 ° C., the voltage was turned off, and the voltage holding ratio after 16.7 msec was measured. Afterimage erasing time: After applying a DC voltage of 15 V for 1 hour to the liquid crystal display element, the voltage was turned off, and the time until the afterimage was erased was visually measured.

Synthesis Example 1 44.8 g of 2,3,5-tricarboxycyclopentylacetic 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. Next, the reaction solution was poured into a large excess of methanol to precipitate polyamic acid. Thereafter, the polymer 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 were 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, no peak corresponding to compound C was detected. The sensitivity of the measurement is 5 × 10 ⁻⁵ parts by weight based on 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
0 g of γ-butyrolactone and 21.6 of pyridine.
g and 16.74 g of acetic anhydride were added, and an imidization reaction was performed at 120 ° C. for 3 hours. Next, 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 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. A-
The imidization reaction was carried out in the same manner as in Synthesis Example 2 using 2) to obtain a polymer (B-2) 2 having an intrinsic viscosity of 1.16 dl / g.
2.2 g were obtained. The polymer (B-2) was analyzed in the same manner as in Synthesis Example 2, but no peak corresponding to Compound C was detected.

Synthesis Example 4 The same procedure as in Synthesis Example 1 was conducted except that the tetracarboxylic dianhydride was changed to 39.22 g of cyclobutanetetracarboxylic dianhydride, and the intrinsic viscosity was 1.26 dl / g.
50.5 g of a polymer (A-3) was obtained. This polymer (A
-3) was analyzed for compound C in the same manner as in Synthesis Example 1, but no peak corresponding to these was detected.

Synthesis Example 5 In Synthesis Example 1, the tetracarboxylic dianhydride was changed to 1,
3,3a, 4,5,9b-Hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione A polymer (A-4) was obtained in the same manner as in Synthesis Example 1,
Further, an imidation reaction was carried out using this polymer (A-4) 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 the tetracarboxylic dianhydride was changed to 43.6 g of pyromellitic dianhydride. A-
5) 60.5 g was obtained. This polymer (A-5) was analyzed by gas chromatography in the same manner as in Synthesis Example 1, and no peak corresponding to compound C was detected.

Example 1 100 g of the polymer ( B-1 ) obtained in Synthesis Example 2 and 0.005 g of pyridine were dissolved in N-methyl-2-pyrrolidone to obtain a solution having a solid concentration 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 a liquid crystal alignment film coating printer using ITO.
A transparent electrode surface is coated on a glass substrate with a transparent electrode made of a film, and dried at 180 ° C. for 1 hour.
m was formed. Using a rubbing machine having a roll in which a rayon cloth is wound around the coating film, the number of rotation of the roll is 500 rpm, and the moving speed of the stage is 1 cm /
A rubbing treatment was performed for 0.6 seconds with a hair foot pressing length of 0.6 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, a nematic type liquid crystal (manufactured by Merck, Z
After filling LI-5080), the liquid crystal injection port is sealed with an epoxy-based adhesive, polarizing plates are provided on both outer surfaces of the substrate, and the polarizing direction of the polarizing plate matches the rubbing direction of the liquid crystal alignment film of each substrate. Then, a liquid crystal display device was manufactured, and the orientation, the voltage holding ratio, and the afterimage erasing time were evaluated. The results are shown in Table 1.

Examples 2 to 18 In the same manner as in Example 1, except that the polymer B obtained in Synthesis Examples 2 to 4 and the compound C shown in the table were used to prepare a liquid crystal aligning agent. A liquid crystal display device was manufactured and evaluated. The results are shown in Tables 1 and 2.

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

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

Comparative Example 3 The polymer (A-5) obtained in Synthesis Example 6 was prepared in the same manner as in Example 1 except that pyridine was not added.
-A liquid crystal aligning agent was prepared by dissolving the compound in pyrrolidone, and a liquid crystal aligning film and a liquid crystal display element were prepared using the liquid crystal aligning agent. 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, after applying a voltage to the liquid crystal display element, the afterimage erasing time when the voltage is erased is short, the voltage holding ratio is high, and the alignment of the liquid crystal is good. A liquid crystal alignment film can be obtained. In addition, a liquid crystal display device having a liquid crystal alignment film formed by using the liquid crystal alignment agent of the present invention can provide SH (Super) by selecting a liquid crystal to be used.
Homeotropic), ferroelectric and antiferroelectric liquid crystal display devices. Further, a liquid crystal display device having an alignment film formed using the liquid crystal alignment agent of the present invention has excellent liquid crystal alignment and reliability, and can be effectively used for various devices, for example, a desk calculator, a wristwatch, a clock, and a coefficient. It is used for display devices such as display boards, word processors, personal computers, and liquid crystal televisions.

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yasuo Matsuki 2--11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic Rubber Co., Ltd. Examiner Yoshiyuki Fujioka (56) References JP-A-5-273558 (JP, A (58) Fields surveyed (Int. Cl. ⁷ , DB name) G02F 1/1337 C08L 79/08

Claims (2)

(57) [Claims] (A) tetracarboxylic dianhydride and dia
To remove the polyamic acid obtained by reacting
100 parts by weight of a water-closed 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 compound in the molecule.
A liquid crystal aligning agent, comprising 5 × 10 ^{−5 to} 5 × 10 ⁻² parts by weight of at least one compound selected from compounds containing three tertiary amino groups . 2. A liquid crystal aligning agent according to claim 1.
Liquid crystal display element comprising a liquid crystal alignment film
Child.