KR20030019247A - Vertical Alignment Type Liquid Crystal Aligning Agent and Liquid Crystal Display Device Using the Same - Google Patents

Abstract

PURPOSE: To provide a vertically aligning-type liquid crystal aligner having excellent vertical alignability, giving short erasing time of an afterimage of a liquid crystal display element, and preferably used for a liquid crystal display element of EVA system or of photo-aligning system photo-aligning by polarized UV-ray irradiation, and a liquid crystal display element using the aligner. CONSTITUTION: This vertically aligning-type liquid crystal aligner comprises a polyamic acid and/or imidized polymer thereof containing a specific structure diamine.

Description

Vertical alignment liquid crystal aligning agent and liquid crystal display device using the same {Vertical Alignment Type Liquid Crystal Aligning Agent and Liquid Crystal Display Device Using the Same}

This invention relates to a vertical alignment liquid crystal aligning agent and the liquid crystal display element using the same. More specifically, the vertical alignment of the photo-alignment method in which the vertical alignment, printability, afterimage erasing time of the liquid crystal display element is short, and the liquid crystal display element of the EVA (Electrically tilted Vertical Alignment) method or the liquid crystal alignment layer are aligned by irradiating polarized ultraviolet light. It relates to a vertical alignment type liquid crystal aligning agent particularly suitable for a type liquid crystal display element or the like.

Currently, as a liquid crystal display element, the liquid crystal aligning film which consists of a polyamic acid, a polyimide, etc. is formed in the surface of the board | substrate with which the transparent conductive film is provided, and it is set as the board | substrate for liquid crystal display elements, and the two sheets are opposingly arranged, and positive dielectric is provided in the clearance gap. A so-called TN (Twisted Nematic) liquid crystal cell in which a layer of a nematic liquid crystal having anisotropy is formed to form a sandwich cell, and the long axis of the liquid crystal molecules is continuously twisted 90 degrees from one substrate to the other substrate. TN type liquid crystal display elements having a known type are known. Moreover, STN (Super Twisted Nematic) type | mold liquid crystals and a vertically oriented liquid crystal display element which have a high contrast compared with a TN type liquid crystal display element and its visual dependence are few. This STN type liquid crystal display element uses a mixture of nematic liquid crystals and a chiral agent, which is an optically active substance, as a liquid crystal, and the birefringence effect that occurs when the major axis of the liquid crystal molecules is continuously twisted over 180 degrees between the substrates. To use.

In this regard, reference is made to "liquid crystal" vol. 3 No. 4272 (1999), an EVA method for studying the electrode structure to control the orientation direction, and light irradiation as published in Jpn Appl, phys. Vol 36 428 (1997). The vertical alignment type liquid crystal display element, such as the photo-alignment system which modifies an oriented film and adjusts an orientation direction, is proposed. These vertically-aligned liquid crystal display elements are excellent also in the viewpoint of a manufacturing process, such as being excellent in viewing angle, contrast, etc., and not having to perform a rubbing process in formation of a liquid crystal aligning film. However, the performance is still insufficient compared with the TN type and STN type liquid crystal display elements mentioned above, and the performance improvement regarding the vertical alignment property and the afterimage erase time of a liquid crystal display element is desired especially.

An object of the present invention is excellent in the vertical alignment property, and vertically used suitably for the liquid crystal display element of the EVA system and the liquid crystal display element of the photo-alignment system which photo-aligned by polarized ultraviolet irradiation by the short afterimage erasing time of a liquid crystal display element. An alignment type liquid crystal aligning agent and a liquid crystal display element using the same are provided.

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

BRIEF DESCRIPTION OF THE DRAWINGS The schematic diagram of the liquid crystal cell of EVA system used for the Example of this invention.

<Description of the code>

1 Color filter side electrode (ITO)

2 liquid crystal aligning film

3 pixel electrode (ITO)

4 liquid crystal molecules

5 Orientation control means (slits)

According to the present invention, the above object and advantage of the present invention is a polymer having at least one repeating unit selected from the repeating unit represented by the following formula (1) and the repeating unit represented by the following formula (2) (hereinafter also referred to as "specific polymer") It is achieved by the perpendicular | vertical alignment type liquid crystal aligning agent characterized by containing.

In formula, P <^1> , P <^2> are tetravalent organic groups, respectively, Q <^1> , Q <^2> is group represented by following formula (3) or (4), respectively.

Wherein X is 2 selected from -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH-, -S-, methylene group, an alkylene group having 2 to 6 carbon atoms and a phenylene group Is a valent group, R ¹ is an alkyl group having 10 to 20 carbon atoms, a monovalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms, or a monovalent organic group having a fluorine atom having 6 or more carbon atoms, and R ² is 4 to 40 carbon atoms. It is a divalent organic group which has alicyclic skeleton.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

As for the vertical alignment liquid crystal aligning agent (henceforth simply a "liquid crystal aligning agent") of this invention, a specific polymer is melt | dissolved in the organic solvent. The said specific polymer is an imidation polymer which has a structure obtained by dehydrating ring closure (imidization) of polyamic acid or this polyamic acid. The imidized polymer may be a 100% dehydration ring closure (imidized) polyimide or a partially dehydrated ring closure (imidized) polymer. In addition, the liquid crystal aligning agent of the present invention may contain both a polyamic acid and an imidized polymer. It is preferable that the liquid crystal aligning agent of this invention has 5 mol% or more of the repeating unit whose polymer component is represented by the said General formula (3) among all the repeating units.

[Polyamic acid]

Tetracarboxylic dianhydride

As tetracarboxylic dianhydride used for the synthesis | combination of the said polyamic acid, alicyclic tetracarboxylic dianhydride is preferable. Specific examples of the alicyclic tetracarboxylic dianhydride include, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxyl Acid dianhydrides, 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, 1,2,4 , 5-cyclohexanetetracarboxylic dianhydride, 3,3 ', 4,4'-dicyclohexyltetracarboxylic dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1 , 2,5,6-tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5 : 6-anhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5 ( Tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5 -Methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b Hexahydro-5-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-7-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1 , 3,3a, 4,5,9b-hexahydro-7-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1, 3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -Furan-1,3-dione, 1,3,3a, 4,5,9b-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-fura Nil) -naphtho [1,2-c] -furan-1,3-dione, 5- (2,5-dioxotetrahydrofural) -3-methyl-3 -Cyclohexene-1,2-dicarboxylic dianhydride, bicyclo [2,2,2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 3-oxabi Cyclo [3,2,1] octane-2,4-dione-6-spiro-3 '-(tetrahydrofuran-2', 5'-dione), the compounds represented by the following formulas (5) and (6), and the like. have.

In formula, R <^3> and R <^5> represents the divalent organic group which has an aromatic ring, R <^4> and R <^6> represent a hydrogen atom or an alkyl group, and two or more R <^4> and R <^6> may be same or different, respectively.

As other tetracarboxylic dianhydride, Aliphatic tetracarboxylic dianhydride, such as butane tetracarboxylic dianhydride; Pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenylsulfontetracarboxylic 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-furtetracarboxylic acid Dianhydrides, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfide dianhydrides, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydrides, 4, 4'-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ', 4,4'-perfluoroisopropylidenediphthalic dianhydride, 3,3', 4,4 ' Biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphineoxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride , m-phenylene-bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4'-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4'-diphenylmethane dianhydride , Ethylene glycol bis (anhydrous trimellitate), propylene glycol bis (anhydrous trimellitate), 1,4-butanediol-bis (anhydrous trimellitate), 1,6-hexanediol-bis (anhydrous trimellitate) ), 1,8-octanediol-bis (anhydrous trimellitate), 2,2-bis (4-hydroxyphenyl) propane-bis (anhydrous trimellitate), compounds represented by the following formulas 7 to 10, and the like Aromatic tetracarboxylic dianhydride is mentioned. These are used individually by 1 type or in combination of 2 or more types.

1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride in the alicyclic tetracarboxylic dianhydride , 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3, 5-tricarboxycyclopentylacetic dianhydride, 5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, cis-3,7- Dibutylcycloocta-1,5-diene-1,2,5,6-tetracarboxylic dianhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6 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-diox 3-furanyl) -naphtho [1,2-c] furan-1,3-dione, bicyclo [2,2,2] -oct-7-ene-2,3,5,6-tetracar Acid dianhydride, 3-oxabicyclo [3,2,1] octane-2,4-dione-6-spiro-3 '-(tetrahydrofuran-2', 5'-dione), Among the compounds to be represented, compounds represented by the following formulas (11) to (13) and compounds represented by the formula (6) among the compounds represented by the formula (14) are preferable from the viewpoint of being able to express good liquid crystal alignment, and particularly preferred are 1,2, 3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione , cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6-tetracarboxylic dianhydride, 3,5,6-tricarbonyl-2- Carboxynorbornane-2: 3,5: 6-anhydride, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3- Furanyl) -naphtho [1,2-c] furan-1,3-dione, 3-oxabicyclo [3,2,1] octane-2,4-dione-6-spiro-3 '-(tetra Hydrofuran-2 ', 5'-dione) and the compound represented by following formula (11).

Preferred among other tetracarboxylic dianhydrides include butanetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenylsulfontetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, etc. are mentioned.

It is preferable that alicyclic tetracarboxylic dianhydride is 50 mol% or more with respect to all tetracarboxylic dianhydride among these tetracarboxylic dianhydrides.

<Diamine>

The groups represented by the above formulas (3) and (4) are groups derived from diamines for synthesizing polyamic acid. Hereinafter, the diamine which has group represented by the said General formula (3) or said General formula (4) is also called "specific diamine."

In the above formula (3), examples of the alkyl group having 10 to 20 carbon atoms represented by R ¹ include n-decyl group, n-dodecyl group, n-pentadecyl group, n-hexadecyl group, n-octadecyl group, n-eicosyl group etc. are mentioned.

In addition, examples of the organic group having an alicyclic skeleton having 4 to 40 carbon atoms represented by R ¹ of Formula 3 and R ² of Formula 4 include cycloalkanes such as cyclobutane, cyclopentane, cyclohexane, and cyclodecane. Groups having an alicyclic skeleton derived; Groups having a steroid skeleton such as cholesterol and cholestanol; The group which has bridge | crosslinked alicyclic skeleton, such as norbornene and adamantane, etc. are mentioned. Among them, particularly preferred are n-octadecyl group, a group having an alicyclic skeleton derived from cyclohexane, and a group having a steroid skeleton. The organic group having the alicyclic skeleton may be a group substituted with a halogen atom, preferably a fluorine atom.

Moreover, as group which has a C6 or more fluorine atom represented by R <^1> of said Formula (3), For example, C6 or more linear alkyl groups, such as n-hexyl group, n-octyl group, n-decyl group; Alicyclic hydrocarbon groups having 6 or more carbon atoms such as a cyclohexyl group and a cyclooctyl group; The group which substituted one part or all part of the hydrogen atom in organic groups, such as a C6 or more aromatic hydrocarbon group, such as a phenyl group and a biphenyl group, with the fluorine atom or the fluoroalkyl group is mentioned.

Moreover, as a divalent organic group represented by X of the said General formula (3) and the said General formula (4) -O-, -COO-, -OCO-, -NHCO-, -CONH, -CO-, methylene group, C2-C6 Alkylene group and a phenylene group, Especially preferable among these is group represented by -O-, -CO0-, -0CO-.

Specific examples of the diamine having a group represented by the formula (3) is dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, Octadecanoxy-2, 4- diamino benzene and the compound represented by following formula (15)-22 are mentioned as a preferable thing.

In addition, as a specific example of the diamine which has a group represented by the said General formula (4), the diamine represented by following General formula (23)-27 is mentioned as a preferable thing.

In the synthesis of the polyamic acid used in the present invention, other diamine compounds may be used in combination so as not to impair the effects of the present invention. As another diamine compound, p-phenylenediamine, m-phenylenediamine, 4,4'- diamino diphenylmethane, 4,4'- diamino diphenylethane, 4,4'- diaminodi, for example. Phenylsulfide, 4,4'-diaminodiphenylsulfone, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminobenzanilide, 4,4'-diaminodi Phenyl ether, 1,5-diaminonaphthalene, 3,3-dimethyl-4,4'-diaminobiphenyl, 5-amino-1- (4'-aminophenyl) -1,3,3-trimethylindan, 6-amino-1- (4'-aminophenyl) -1,3,3-trimethylindane, 3,4'-diaminodiphenylether, 3,3'-diaminobenzophenone, 3,4'-dia Minobenzophenone, 4,4'-diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] Hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] sulfone, 1,4-bis (4-aminophenoxy Benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3- Aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -10-hydroanthracene, 2,7-diaminofluorene, 9,9-bis (4-aminophenyl) fluorene, 4,4 ' Methylene-bis (2-chloroaniline), 2,2 ', 5,5'-tetrachloro-4,4'-diaminobiphenyl, 2,2'-dichloro-4,4'-diamino-5 , 5'-dimethoxybiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 1,4,4 '-(p-phenyleneisopropylidene) bisaniline, 4,4' -(m-phenyleneisopropylidene) bisaniline, 2,2'-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4'-diamino Aromatic diamines such as -2,2'-bis (trifluoromethyl) biphenyl and 4,4'-bis [(4-amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl;

1,1-methaxylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1 , 4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindenylenedimethylenediamine, tricyclo [6.2.1.0 ^2,7 ] -undecylenedimethyldiamine Aliphatic and alicyclic diamines such as 4,4'-methylenebis (cyclohexylamine);

2,3-diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 5,6-diamino-2,3-dicyanopyrazine, 5, 6-diamino-2,4-dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 1,4-bis (3-aminopropyl) piperazine, 2,4-diamino-6-isopropoxy-1,3,5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino- 6-phenyl-1,3,5-triazine, 2,4-diamino-6-methyl-s-triazine, 2,4-diamino-1,3,5-triazine, 4,6-dia Mino-2-vinyl-s-triazine, 2,4-diamino-5-phenylthiazole, 2,6-diaminopurine, 5,6-diamino-1,3-dimethyluracil, 3,5- Diamino-1,2,4-triazole, 6,9-diamino-2-ethoxyacridine lactate, 3,8-diamino-6-phenylphenanthtridine, 1,4-diaminopiperazine, In the molecule | numerators, such as 3, 6- diamino acridine and bis (4-aminophenyl) phenylamine, other than two primary amino groups and the said primary amino group Diamines having a nitrogen atom;

And diamino organosiloxane represented by the following formula (28).

In formula, R <^7> represents a C1-C12 hydrocarbon group, two or more R <^7> may be same or different, p is an integer of 1-3, q is an integer of 1-20.

These diamine compounds can be used individually or in combination of 2 or more types.

Among them, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 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, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine and the like This is preferred.

The proportion of the specific diamine in the total diamine components of all the polymers contained in the liquid crystal aligning agent of the present invention is preferably 5 mol% or more, more preferably 10 mol% or more based on the total amount of the diamine components. When this use ratio is less than 5 mol%, the effect sufficient for vertical alignment may not be acquired in some cases.

Synthesis of Polyamic Acid

The use ratio of the tetracarboxylic dianhydride and the diamine provided in the polyamic acid synthesis reaction is preferably a ratio in which the acid anhydride group of the tetracarboxylic dianhydride is 0.2 to 2 equivalents to 1 equivalent of the amino group of the diamine. Preferably it is the ratio which becomes 0.3 to 1.2 equivalent.

The synthesis reaction of the polyamic acid is usually carried out in an organic solvent under a temperature condition of -20 ° C to 150 ° C, preferably 0 to 10 ° C.

The organic solvent is not particularly limited as long as it can dissolve the polyamic acid synthesized. For example, 1-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, Aprotic polar solvents such as dimethyl sulfoxide, γ-butyrolactone, tetramethylurea and hexamethylphosphotriamide; Phenol solvents, such as m-cresol, xylenol, a phenol, and a halogenated phenol, can be illustrated. In addition, the amount of the organic solvent (a) is preferably preferably an amount such that the total amount (β) of the tetracarboxylic dianhydride and the diamine compound is 0.1 to 30% by weight based on the total amount (α + β) of the reaction solution.

In addition, the organic solvent may be used in combination such that alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons and the like which are empty solvents of the polyamic acid are not precipitated. As specific examples of these empty solvents, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol, propylene glycol, 1,4-butanediol, Triethylene glycol, ethylene glycol monomethyl ether, ethyl lactate, butyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl methoxy propionate, ethyl ethoxy Propionate, 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 dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol mono Methyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane And chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene and the like.

As described above, a reaction solution obtained by dissolving polyamic acid is obtained. The reaction solution is poured into a large amount of empty solvent to obtain a precipitate, and the polyamic acid can be obtained by drying the precipitate under reduced pressure. In addition, the polyamic acid can be purified by dissolving the polyamic acid again in an organic solvent and then precipitating with an empty solvent once or several times.

<Dehydration ring closure reaction>

The specific polymer constituting the liquid crystal aligning agent of the present invention can be synthesized by dehydrating and closing some or all of the polyamic acid. The specific polymer used for this invention has 40 mol% or more of ratio of the repeating unit which has an imide ring in all the repeating units (henceforth "imidization ratio"), Preferably it is 50 mol% or more. By using the polymer whose imidation ratio is 40 mol% or more, the liquid crystal aligning agent which can form a liquid crystal aligning film with a short residual image removal time can be obtained.

The dehydration ring closure of polyamic acid may be performed by (i) heating the polyamic acid or (ii) dissolving the polyamic acid in an organic solvent and adding a dehydrating agent and a dehydration ring closure catalyst to the solution, and heating it as necessary. Is done by.

The reaction temperature in the method of heating the polyamic acid of said (i) becomes like this. Preferably it is 50-200 degreeC, More preferably, it is 60-170 degreeC. When reaction temperature is less than 50 degreeC, dehydration ring-closure reaction does not fully advance, and when reaction temperature exceeds 200 degreeC, the molecular weight of the imidation polymer obtained may fall.

On the other hand, in the method of adding the dehydrating agent and the dehydrating ring-closure catalyst in the solution of the polyamic acid of the above (ii), as the dehydrating agent, for example, acid anhydrides such as acetic anhydride, propionic anhydride and trifluoroacetic anhydride can be used. . The amount of the dehydrating agent to be used depends on the desired imidation ratio, but it is preferably set to 0.01 to 20 moles with respect to 1 mole of the repeating unit of the polyamic acid. As the dehydration ring closure catalyst, tertiary amines such as pyridine, coridine, lutidine and triethylamine can be used, for example. However, it is not limited to these. It is preferable that the usage-amount of a dehydration ring-closure catalyst shall be 0.01-10 mol with respect to 1 mol of dehydrating agents used. The imidation ratio can be made higher as the usage-amount of the said dehydrating agent and a dehydrating ring closure agent increases. Moreover, the organic solvent illustrated as what is used for the synthesis | combination of a polyamic acid is mentioned as an organic solvent used for dehydration ring-closure reaction. And the reaction temperature of dehydration ring-closure reaction becomes like this. Preferably it is 0-180 degreeC, More preferably, it is 10-150 degreeC. Moreover, the specific polymer obtained by performing the same operation as the purification method of polyamic acid about the reaction solution obtained in this way can be refine | purified.

<Polymer of Terminal Modified Type>

Particular polymers used in the present invention are preferably terminally modified with molecular weight. By using this terminal modified polymer, the coatability of a liquid crystal aligning agent, etc. can be improved, without the effect of this invention being impaired. These terminal-modified polymers can be synthesized by adding an acid-anhydride, a monoamine compound, a monoisocyanate compound and the like to the reaction system when synthesizing the polyamic acid. Here, examples of the acid-anhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic anhydride, n-hexadecylsuccinic anhydride, and the like. Can be. As the monoamine compound, 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 -An eicosylamine etc. are mentioned. Moreover, as a monoisocyanate compound, phenyl isocyanate, naphthyl isocyanate, etc. are mentioned, for example.

Logarithmic viscosity of the polymer

The value of the logarithmic viscosity (η _ln ) of the polyamic acid obtained as described above is preferably 0.05 to 10 dl / g, more preferably 0.05 to 5 dl / g.

The value of the logarithmic viscosity (η _ln ) in the present invention uses N-methyl-2-pyrrolidone as a solvent, measures the viscosity at 30 ° C for a solution having a concentration of 0.5 g / 100 ml, It is calculated | required by Formula 1.

[Liquid crystal aligning agent]

The liquid crystal aligning agent of this invention consists of the said specific polymer melt | dissolving in the organic solvent normally.

The temperature at the time of manufacturing the liquid crystal aligning agent of this invention becomes like this. Preferably it is 0 degreeC-200 degreeC, More preferably, it is 20 degreeC-60 degreeC.

As an organic solvent which comprises the liquid crystal aligning agent of this invention, 1-methyl- 2-pyrrolidone, (gamma) -butyrolactone, (gamma) -butyrolactam, N, N- dimethylformamide, N, N- Dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxy propionate, ethyl ethoxy propionate, ethylene glycol methyl ether, ethylene Glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether Diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, and the like. Can be.

Although solid content concentration of the liquid crystal aligning agent of this invention is selected in consideration of viscosity, volatility, etc., Preferably it is the range of 1 to 10 weight%. That is, when the liquid crystal aligning agent of this invention is apply | coated to the board | substrate surface, and the coating film used as a liquid crystal aligning film is formed, but solid content concentration is less than 1 weight%, the film thickness of this coating film is too thin and a favorable liquid crystal aligning film is not obtained, solid content concentration When exceeds 10 weight%, the film thickness of a coating film is too thick and a favorable liquid crystal aligning film cannot be obtained, Furthermore, the viscosity of a liquid crystal aligning agent increases and applicability | paintability is inferior.

The liquid crystal aligning agent of this invention can contain a functional silane containing compound and an epoxy compound from a viewpoint of improving adhesiveness to the surface of a board | substrate within the range which does not damage the target substance. As such a functional silane containing compound, 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 2-aminopropyl trimethoxysilane, 2-aminopropyl triethoxysilane, N- ( 2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltrier Methoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-tri Methoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecan, 10-triethoxysilyl-1,4,7-triazadecan, 9-trimethoxysilyl- 3,6-diazanyl acetate, 9-triethoxysilyl-3,6-diazanyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-ben Jyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyltri Methoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, etc. are mentioned. As these epoxy compounds, for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, Neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5, 6-tetraglycidyl-2,4-hexanediol, N, N, N ', N'-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl ) Cyclohexane, N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane, 3- (N-allyl-N-glycidyl) aminopropyltrimethoxysilane, 3- (N, N- diglycidyl) aminopropyltrimethoxysilane etc. are mentioned.

<Liquid crystal display element>

The liquid crystal display element obtained using the liquid crystal aligning agent of this invention can be manufactured by the following method, for example.

(1) The liquid crystal aligning agent of this invention is apply | coated to one surface of the board | substrate with which the patterned transparent conductive film is provided, for example by methods, such as a roll coater method, a spinner method, and a printing method, and it heats a coating surface subsequently, To form. Here, as a board | substrate, For example, glass, such as a float glass and a soda glass; A transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone and polycarbonate can be used. As the transparent conductive film provided on one surface of the substrate, an NESA film (registered trademark of PPG Co., Ltd.) made of tin oxide (SnO ₂ ), an ITO film made of indium tin oxide (In ₂ O ₃ -SnO ₂ ), or the like is used. It can be used, The photo-etching method and the method of using a mask beforehand are used for patterning of these transparent conductive films. Furthermore, in order to define the orientation direction of a liquid crystal, the liquid crystal display element which improved the viewing angle dependency by the method of forming a processus | protrusion structure, or forming a slit in an electrode can be obtained in a board | substrate. In application | coating of a liquid crystal aligning agent, in order to make adhesiveness of the surface of a board | substrate and a transparent conductive film, and the film of a liquid crystal aligning agent more favorable, a functional silane containing compound, a functional titanium containing compound, etc. are previously apply | coated to the said surface of a board | substrate. can do. Moreover, heating temperature is 80-250 degreeC, Preferably it is 120-200 degreeC. The film thickness of the formed film is usually from 0.01 to 1 mu m, preferably from 0.05 to 0.5 mu m. In addition, although the liquid crystal aligning agent of this invention forms the film which turns into a liquid crystal aligning film by removing an organic solvent after application | coating, it can also be made into the film which imidated or fully imidated by advancing dehydration ring closure by heating.

(2) A liquid crystal aligning ability is provided to the formed film surface. As this method, the rubbing process which rubs in a fixed direction with the roll which rolled cloth which consists of fibers, such as a nylon, rayon, and cotton, is performed, for example, or the orientation surface is provided by irradiating a polarized ultraviolet-ray, an ion beam, an electron beam, etc. to the film surface. Method is suitably used. Moreover, a liquid crystal aligning film can also be formed by the method of obtaining a film by the uniaxial stretching method, the Langmuir-Blodgett method, etc. Moreover, in order to remove the fine powder (foreign substance) which arises at the time of a rubbing process, and to make a surface clean, it is preferable to wash the formed liquid crystal aligning film with isopropyl alcohol etc. Moreover, the process which changes a pretilt angle by partially irradiating an ultraviolet-ray, an ion beam, an electron beam, etc. to the surface of the formed liquid crystal aligning film (for example, Unexamined-Japanese-Patent No. 6-222366, Unexamined-Japanese-Patent No. 6-281937). Japanese Patent Laid-Open Publication No. Hei 7-168187 and Japanese Laid-Open Patent Publication No. Hei 8-234207), the resist film is partially formed on the surface of the formed liquid crystal alignment film, and the rubbing treatment is performed in a direction different from the preceding rubbing treatment. After the removal, the resist film is removed and the treatment for changing the alignment ability of the liquid crystal alignment film (see, for example, Japanese Patent Application Laid-Open No. H5-107544) can improve the viewing angle characteristics of the liquid crystal display device to be produced. have.

(3) As described above, two substrates on which a liquid crystal alignment film was formed were prepared, were disposed to face each other through a gap (cell gap), and the peripheral portions of the two substrates were bonded together using a sealant to the substrate surface and the sealant. The liquid crystal is injected and filled into the cell gap partitioned by this, and the injection hole is sealed to form a liquid crystal cell. And a liquid crystal display element is obtained by bonding a polarizing plate to the outer surface of a liquid crystal cell, ie, the other surface side of each board | substrate which comprises a liquid crystal cell.

As the sealant, for example, an epoxy resin or the like containing an aluminum oxide sphere as a curing agent and a spacer can be used.

Examples of the liquid crystals include nematic liquid crystals and smectic liquid crystals. Among them, nematic liquid crystals are preferable, and for example, a sipe salt liquid crystal, a cyan salt liquid crystal, a biphenyl liquid crystal, a phenylcyclohexane liquid crystal, an ester liquid crystal, A terphenyl type liquid crystal, a biphenyl cyclohexane type liquid crystal, a pyrimidine type liquid crystal, a dioxane type liquid crystal, a bicyclooctane type liquid crystal, a cuban type liquid crystal, etc. can be used. Moreover, it is sold to these liquid crystals as cholesteric liquid crystals, such as a cholesteryl chloride, a cholesteryl nonaate, a cholesteryl carbonnet, and a brand name "C-15" "CB-15" (made by Merck), for example. The chiral agent etc. which are like can be added.

Moreover, as a polarizing plate bonded to the outer surface of a liquid crystal cell, the polarizing plate which consists of a polarizing plate which inserted the polarizing film called H film which absorbed iodine, and extended | stretched polyvinyl alcohol by the cellulose acetate protective film, or the H film itself is mentioned.

The liquid crystal aligning agent of this invention can be used suitably for the liquid crystal display element of EVA system. The EVA method is described in "liquid crystal" vol. 3 No. 4 272 (1999) shows a vertical alignment method of adjusting the orientation direction by studying the electrode structure and installing the slits. The slit can be formed on each of the TFT substrate side and the color filter side.

Further, the liquid crystal aligning agent of the present invention is described in "Jpn Appl. Phys." Vol 36 428 (1997), it can be used suitably for the vertical alignment type liquid crystal display element of the photo-alignment system by polarized ultraviolet irradiation. It is preferable that the polarized ultraviolet ray used in the said liquid crystal display element is an ultraviolet-ray linearly polarized.

<Example>

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[Measuring Method of Imidization Rate of Specific Polymer]

After drying the polymer under reduced pressure at room temperature, it was dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference material, and was determined by the formula represented by the following formula (2).

A ¹ : peak area derived from NH proton (10 ppm)

A ² : peak area derived from other protons

α: ratio of the number of other protons to one proton of the NH group in the precursor of the polymer (polyamic acid)

[Production Method of Liquid Crystal Display Element]

Fabrication of Liquid Crystal Display Devices:

(1) EVA cell

As shown in FIG. 1, as a model element corresponding to EVA system, a liquid crystal aligning agent is printed on two glass substrates which have a pattern of ITO, and it dries by drying at 80 degreeC for 1 minute, and then at 180 degreeC for 1 hour. A coating film having a film thickness of 600 kPa was formed. After the epoxy resin-based adhesive containing aluminum oxide spheres having a particle size of 3.5 µm was applied to the outer edges of one substrate by screen printing, as shown in FIG. Each substrate was bonded. Merck's negative liquid crystal MLC6608 was injected and filled into the cell gap partitioned by the adhesive on the surface of the substrate and the outer edge portion, and then the injection hole was sealed with an epoxy adhesive to prepare a vertically aligned liquid crystal display device.

(2) photo-alignment cells

As a model element corresponding to the vertical photo-alignment method, a liquid crystal aligning agent was printed on two glass substrates with ITO, respectively, and it dried for 1 minute at 80 degreeC, and then at 180 degreeC for 1 hour, and the coating film of 600 mm of dry film thicknesses was carried out. Formed. In addition, each board | substrate was irradiated for 3 minutes with the irradiation intensity of 1.0 J / cm <^2> in 45 degree direction from the film surface by the ultraviolet-ray of linearly polarized light which mainly made 365 nm wavelength using a mercury lamp. After the epoxy resin adhesive containing the aluminum oxide sphere with a particle diameter of 3.5 micrometers was apply | coated by the screen printing method to the outer edge part of one board | substrate, it bonded together so that the light irradiation direction to each board | substrate might be 180 degrees (antiparallel). . MLC6608 was injected in the same manner as the EVA cell, and the injection port was sealed to manufacture a vertically aligned liquid crystal display device.

[Vertical orientation]

The liquid crystal display element at voltage OFF and alternating current 12 V (peak-peak) was observed under cross nicol.

[Voltage retention rate]

After applying a voltage of 5 V to the liquid crystal display element in an application time of 60 microseconds and a period of 167 milliseconds, the voltage retention after 167 milliseconds from the release of the application was measured. The measurement apparatus used VHR-1 by Toyo Technica.

Afterimage erasing time of liquid crystal display element

After applying a 30 Hz, 3.0 V rectangular wave superimposed on a liquid crystal display device with a direct current 3.0 V and an AC 6.0 V (peak-peak) for 20 hours at an environmental temperature of 70 ° C., the voltage was turned off, and the afterimage was visually observed. The time to erasure was measured.

Synthesis of Specific Polymer

<Synthesis Examples 1 to 7>

Diamine and tetracarboxylic dianhydride were added to 1-methyl-2-pyrrolidone in the composition shown in Table 1, and the mixture was reacted for 6 hours at a solid content concentration of 20% and 60 ° C to have a logarithmic viscosity shown in Table 1. Polyamic acid was obtained.

Number in () is mole%

TCAAH: 2,3,5-tricarboxycyclopentylacetic dianhydride

CB: 1,2,3,4-cyclobutanetetracarboxylic dianhydride

MTDA: 1,3,3a, 4,5,9b-hexahydro-8-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan- 1,3-dione

PDA: p-phenylenediamine

ODA: Octadecanoxy-2,4-diaminobenzene

Diamine ①: diamine represented by the formula (15)

Diamine ②: diamine represented by the formula (16)

Diamine ③: diamine represented by the formula (19)

<Synthesis Examples 8-17>

The polyamic acid obtained in Synthesis Examples 1 to 7 was diluted with 1-methyl-2-pyrrolidone to a solid content concentration of 5%, pyridine and acetic anhydride were added as a catalyst shown in Table 2 as a catalyst, Certain polymers were synthesized by stirring for hours. The polymer solution was reprecipitated with diethyl ether to obtain a white powder of polymer (imidized polymer). The imidation ratio of the obtained specific polymer is shown together in Table 2. In Table 2, pyridine / acid anhydride (double molar) = 1.0 / 1.0 means that 1.0 mole of pyridine and 1.0 mole of acetic anhydride are added to 1.0 mole of amide bonds in the polyamic acid.

Synthesis Examples 18 to 27

Polyamine having a logarithmic viscosity shown in Table 3 was added to 1-methyl-2-pyrrolidone in the composition shown in Table 3 in this order, diamine, tetracarboxylic dianhydride, and reacted at a solid content concentration of 20% for 60 hours for 6 hours. Amic acid was obtained.

The number in () is mole%

TDA: 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3 Dion

TNA: 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-anhydride

CHA: acid anhydride represented by the formula

DDE: 4,4'-diaminodiphenyl ether

Diamine ②: diamine represented by the formula (16)

Diamine ④: diamine represented by the formula (27)

Diamine ⑤: diamine represented by the formula (23)

Diamine ⑥: diamine represented by the formula (22)

Synthesis Examples 29 to 34

By diluting the polyamic acid obtained in the synthesis example to 1% of solids concentration by 1-methyl-2-pyrrolidone, adding pyridine and acetic anhydride shown in Table 4 as a catalyst, and stirring at 110 ° C for 4 hours, Specific polymers were synthesized. The polymer solution was reprecipitated with diethyl ether to obtain a white powder of polymer (imidized polymer). The imidation ratio of the obtained specific polymer is shown together in Table 4. In Table 4, pyridine / acid anhydride (double molar) = 1.0 / 1.0 means that 1.0 mole of pyridine and 1.0 mole of acetic anhydride are added to 1.0 mole of amide bonds in the polyamic acid.

Synthesis Examples 35 to 39

Diamine and tetracarboxylic dianhydride were added to 1-methyl-2-pyrrolidone in the composition shown in Table 5, reacted for 6 hours at a solid content concentration of 20% and 60 ° C, and the logarithmic viscosity shown in Table 5 was obtained. Obtained polyamic acid was obtained.

The number in () is mole%

PMDA: pyromellitic dianhydride

Synthesis Example 40

The polyamic acid obtained in Synthesis Example 39 was diluted with 1-methyl-2-pyrrolidone to a solid content concentration of 5%, and 1.0 mol of pyridine and 1.0 mol of acetic anhydride were added to 1.0 mol of the amide bond in the polyamic acid as a catalyst. And the specific polymer was synthesize | combined by stirring at 110 degreeC for 4 hours. The polymer solution was reprecipitated with diethyl ether to obtain a white powder of polymer (imidized polymer). The imidation ratio of the obtained specific polymer was 50%.

<Examples 1 to 10>

The specific polymer shown in Table 6 was prepared in a mixed solvent of N-methyl-2-pyrrolidone (NMP): butyl cellosolve (BC) = 6: 4 (weight ratio) at a solid content concentration of 6.0% to obtain a vertical orientation of the present invention. A type liquid crystal aligning agent was obtained. The liquid crystal display element was produced using this liquid crystal aligning agent, and various evaluation was performed. The results are shown in Table 6.

<Examples 11 to 27, Comparative Example 1>

As Example 11, 95 g of a specific polymer (Synthesis Example 29) and 5 g of an additive (N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane, hereinafter EP) were added. It melt | dissolved in the mixed solvent of NMP: BC = 5: 5 (weight ratio), was prepared so that solid content concentration might be 6.0%, and the vertically-aligned liquid crystal aligning agent of this invention was obtained. The said liquid crystal display element of said EVA type was produced using this liquid crystal aligning agent, and various evaluation was performed. The results are shown in Table 7. In the same manner as in Example 11, specific liquid crystals, additives, and solvents were mixed at the ratios shown in Tables 7 to 8 to prepare liquid crystal aligning agents, and respective characteristics were evaluated. The results are collectively shown in Tables 7-8.

Silane ①: N-glycidyl-N, N-bis [3- (methyldimethoxysilyl) propyl] amine

BL: γ-butyrolactone

<Example 28>

In the same manner as in Example 11, a specific polymer solution was prepared, to prepare an EVA type cell. The liquid crystal alignment property of the obtained EVA type cell was favorable, and there existed no abnormality, such as a domain, according to voltage ON and OFF. Moreover, the voltage retention of the cell was 99.3% and the afterimage erase time was 40 seconds.

<Example 29>

A specific polymer solution was prepared in the same manner as in Example 11 to prepare a photoaligned cell. The liquid crystal alignment property of the obtained photo-alignment type cell was favorable, and there existed no abnormality, such as a domain, according to voltage ON and OFF. Moreover, the voltage retention of the cell was 98.3% and the afterimage erase time was 95 seconds.

<Examples 30 to 34, Comparative Example 1>

As Example 30, 85 g of a specific polymer (Synthesis Example 35) and EP 15 g as an additive were dissolved in a mixed solvent of NMP: BC = 3: 7 (weight ratio), and the solid content concentration was prepared to be 6.0%, and the present invention The vertical alignment type liquid crystal aligning agent was obtained. The said liquid crystal display element of said EVA type was produced using this liquid crystal aligning agent, and various evaluation was performed. The results are shown in Table 9. In the same manner as in Example 30, specific polymers, additives, and solvents were mixed at the ratios shown in Table 9 to prepare liquid crystal aligning agents, and respective characteristics were evaluated. All the results are shown in Table 9.

According to this invention, the liquid crystal aligning agent and liquid crystal display element suitable for the orientation system (EVA, photo-alignment, etc.) with favorable vertical alignment property and a short residual image erasing time can be obtained. In addition, the liquid crystal display element provided with the liquid crystal aligning film formed using the liquid crystal aligning agent of this invention can be used effectively for various apparatuses, For example, it is a projection system other than the direct-monitor personal computer monitor, liquid crystal television, etc. Used for transmissive and reflective displays.

Claims (2)

A vertical alignment liquid crystal aligning agent comprising a polymer having at least one repeating unit selected from the repeating unit represented by the following formula (1) and the repeating unit represented by the following formula (2). <Formula 1> <Formula 2> In formula, P <^1> , P <^2> are tetravalent organic groups, respectively, Q <^1> , Q <^2> is group represented by following formula (3) or (4), respectively. <Formula 3> <Formula 4> Wherein X is 2 selected from -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH-, -S-, methylene group, an alkylene group having 2 to 6 carbon atoms and a phenylene group Is a valent group, R ¹ is an alkyl group having 10 to 20 carbon atoms, a monovalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms, or a monovalent organic group having a fluorine atom having 6 or more carbon atoms, and R ² is 4 to 40 carbon atoms. It is a divalent organic group which has alicyclic skeleton. The liquid crystal aligning film obtained from the vertically-aligned liquid crystal aligning agent of Claim 1 is provided, The liquid crystal display element characterized by the above-mentioned.