JP5099351B2 - Liquid crystal aligning agent and liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal display element and a liquid crystal aligning agent used for forming the liquid crystal alignment film. More specifically, the present invention relates to a liquid crystal aligning agent that provides a liquid crystal alignment film excellent in printability and electrical characteristics, and a liquid crystal display element using the liquid crystal alignment film.

Currently, as a liquid crystal display element, a liquid crystal alignment film made of polyamic acid or polyimide is formed on a substrate surface provided with a transparent conductive film to form a liquid crystal display element substrate. A nematic liquid crystal layer having positive dielectric anisotropy is formed in a cell having a sandwich structure so that the major axis of the liquid crystal molecules is continuously twisted 90 degrees from one substrate to the other. A TN liquid crystal display element having a so-called TN (twisted nematic) liquid crystal cell is known. Further, STN (Super Twisted Nematic) type liquid crystal display elements and vertical alignment type liquid crystal display elements, which have a higher contrast than the TN type liquid crystal display elements and have less viewing angle dependency, have been developed. This STN type liquid crystal display element uses nematic liquid crystal blended with a chiral agent which is an optically active substance as liquid crystal, and the major axis of liquid crystal molecules is continuously twisted over 180 degrees between substrates. The birefringence effect generated by the above is utilized. On the other hand, as described in Non-Patent Document 1 and Patent Document 1, a vertically aligned liquid crystal display element called an MVA method has been proposed in which protrusions are formed on ITO to control the alignment direction of liquid crystals. Yes. The MVA liquid crystal display element is excellent in terms of manufacturing process, such as excellent viewing angle and contrast, and need not be rubbed in forming the liquid crystal alignment film. As a liquid crystal alignment film suitable for the TN, STN, and MVA methods, performance such as a short afterimage erasing time of the liquid crystal display element is required. In addition, as an alignment agent used for forming these liquid crystal alignment films, excellent printability is required in offset printing.
Japanese Patent Laid-Open No. 11-258605 “Liquid Crystal” Vol. 3 No. 2 117 (1999)

  The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to improve the charge retention while maintaining the voltage holding ratio in the polyimide-based liquid crystal alignment film and further improving the stored charge. A liquid crystal aligning agent having printability and a liquid crystal display element using the same.

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

According to the present invention, the above objects and advantages of the present invention are as follows.
A mixture of a polyamic acid comprising a repeating unit represented by the following formula (A) and a polyimide comprising a repeating unit represented by the following formula (B), a polyimide comprising a repeating unit represented by the following formula (B), and the following formula (1 This is achieved by a liquid crystal aligning agent characterized by containing a compound represented by the following formula (hereinafter also referred to as “specific compound”).

(Wherein P ¹ is a tetravalent organic group and Q ¹ is a divalent organic group.)

(Wherein P ² is a tetravalent organic group and Q ² is a divalent organic group.)

(Wherein two ^{R 1} is either hydrogen atom, Y is -S -, - NH -, - O -, - CH 2 - or a single bond, ^{X 1} and ^{X 2} are each independently And the following structure.)

(In the formula, Z ¹ , Z ² and Z ³ are diglycidylamino groups.)
It is preferable that P ¹ in the above formula (A) and P ² in the above formula (B) are both derived from 2,3,5-tricarboxycyclopentylacetic acid dianhydride.

According to the present invention, the above objects and advantages of the present invention, the second,
This is achieved by a liquid crystal display device comprising a liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention.

  Hereinafter, the present invention will be described in detail.

In the above formula (1), two ^{R 1} is either hydrogen atom. Y is —S—, —NH—, —O—, —CH ₂ — or a single bond. Among these, -S-, -NH- or a single bond is preferable. X ¹ and X ² are any of the following structures.

Of these, any of the following structures is preferred.

In the above formula, Z ¹ , Z ² and Z ³ are diglycidylamino groups .
Specific compounds include

Is mentioned.

[Polyamic acid comprising a repeating unit represented by the above formula (A)]
<Tetracarboxylic dianhydride>
Examples of the tetracarboxylic dianhydride used for the synthesis of polyamic acid that gives P ¹ (tetravalent organic group) in the above formula (A) include, for example, alicyclic tetracarboxylic dianhydrides, alicyclic tetra Carboxylic dianhydrides and aromatic tetracarboxylic dianhydrides are mentioned. Of these, alicyclic tetracarboxylic dianhydrides are preferred. Specific examples of the alicyclic tetracarboxylic dianhydride include, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic Acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1 , 2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5 -Cyclohexanetetracarboxylic dianhydride, 3,3 ', 4,4'-dicyclohexyltetracarboxylic dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6 -Tetracarboxylic acid Anhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-dianhydride, 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-furanyl) -naphtho 1,2-c] -furan-1,3-dione, bicyclo [2.2.2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 3-oxabicyclo [ 3.2.1] Octane-2,4-dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′-dione), a compound represented by each of the following formulas (I) and (II),

(Wherein R ² and R ⁴ represent a divalent organic group having an aromatic ring, R ³ and R ⁵ represent a hydrogen atom or an alkyl group, and a plurality of R ³ and R ⁵ are the same. But it may be different.)
In addition, aliphatic tetracarboxylic dianhydrides such as butanetetracarboxylic dianhydride;
Pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 1,4,5, 8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic dianhydride, 3,3 ′, 4,4′-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ′, 4,4′-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4,4′-bis ( 3,4-dicar Boxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidenediphthalic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 3 , 3 ′, 4,4′-biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis ( Triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4′-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4′-diphenylmethane dianhydride, ethylene glycol-bis ( Anhydrotrimellitate), propylene glycol-bis (anhydrotrimellitate), 1,4-butanediol-bis (anhydrotrimellitate) Retate), 1,6-hexanediol-bis (anhydrotrimellitate), 1,8-octanediol-bis (anhydrotrimellitate), 2,2-bis (4-hydroxyphenyl) propane-bis ( Anhydrotrimellitate) and aromatic tetracarboxylic dianhydrides such as compounds represented by the following formulas (2) to (5). These tetracarboxylic dianhydrides are used alone or in combination of two or more.

  Among the tetracarboxylic dianhydrides, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxy Cyclopentyl acetic acid dianhydride, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 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 -Dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, bicyclo [2.2.2] -oct-7-ene-2,3,5,6-tetracarboxylic acid Dianhydride, 3-oxabicyclo [3.2.1] octane-2,4 Dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′-dione), compounds represented by the following formulas (6) to (8) among the compounds represented by the above formula (I), etc. Among the alicyclic tetracarboxylic dianhydrides and the compounds represented by the above formula (II), the alicyclic tetracarboxylic dianhydrides such as the compounds represented by the following formula (9) have good liquid crystal alignment. It is preferable from the viewpoint of exhibiting sex. Particularly preferred are 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tri Carboxycyclopentyl acetic acid dianhydride, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 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-dianhydride, 1,3,3a, 4 , 5,9b-Hexa Dro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 3-oxabicyclo [3.2.1] octane Examples include -2,4-dione-6-spiro-3 '-(tetrahydrofuran-2', 5'-dione) and compounds represented by the following formula (6).

Among the other tetracarboxylic dianhydrides other than the alicyclic tetracarboxylic dianhydrides, for example, butanetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4, Examples include 4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, and the like.
Among these tetracarboxylic dianhydrides, the alicyclic tetracarboxylic dianhydride is preferably 50 mol% or more based on the total tetracarboxylic dianhydrides.

<Diamine>
Examples of the diamine used in the synthesis of polyamic acid and / or the imidized polymer thereof that give Q ¹ (divalent organic group) in the above formula (A) include p-phenylenediamine, m-phenylenediamine, 4 , 4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, 4,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenylsulfone, 3,3′-dimethyl-4,4′-diaminobiphenyl, 4, , 4′-diaminobenzanilide, 4,4′-diaminodiphenyl ether, 1,5-diaminonaphthalene, 2,2′-dimethyl-4,4′-diaminobiphenyl, 5-amino-1- (4′-aminophenyl) ) -1,3,3-trimethylindane, 6-amino-1- (4′-aminophenyl) -1,3,3-trimethylindane, , 4'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2, , 2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] Sulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-amino) Phenyl) -10-hydroanthracene, 2,7-diaminofluorene, 9,9-bis (4-aminophenyl) fluorene, , 4′-methylene-bis (2-chloroaniline), 2,2 ′, 5,5′-tetrachloro-4,4′-diaminobiphenyl, 2,2′-dichloro-4,4′-diamino-5 , 5′-dimethoxybiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 1,4,4 ′-(p-phenyleneisopropylidene) bisaniline, 4,4 ′-(m-phenyleneisopropylidene) Bisaniline, 2,2′-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 4 , 4′-bis [(4-amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl, N, N′-di (4-aminophenyl) benzidine and other aromatic diamines;
1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1 , 4-diaminocyclohexane, isophorone diamine, tetrahydrodicyclopentadienylenediamine, tricyclo [6.2.1.0 ^2,7 ] -undecylenedimethyl diamine, aliphatic such as 4,4′-methylenebis (cyclohexylamine) And alicyclic diamines;
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-diamino-2-vinyl-s-triazine, 2,4-diamino-5-phenylthiazole, 2,6- Aminopurine, 5,6-diamino-1,3-dimethyluracil, 3,5-diamino-1,2,4-triazole, 6,9-diamino-2-ethoxyacridine lactate, 3,8-diamino-6 Phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, bis (4-aminophenyl) phenylamine, 1- (3,5-diaminophenyl) -3-decylsuccinimide, 1- (3 2-diaminophenyl) -3-octadecylsuccinimide and the compounds represented by each of the following formulas (III) and (IV), etc., and two primary amino groups and nitrogen atoms other than the primary amino group in the molecule Having a diamine;

(Wherein R ⁶ represents a monovalent organic group having a ring structure containing a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine, and X ³ represents a divalent organic group.)

(Wherein X ⁴ represents a divalent organic group having a ring structure containing a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine, R ⁷ represents a divalent organic group, and there are a plurality of them. X ⁴ may be the same or different.)
Monosubstituted phenylenediamine represented by the following formula (V); diaminoorganosiloxane represented by the following formula (VI);

(Wherein R ⁸ represents a divalent organic group selected from —O—, —COO—, —OCO—, —NHCO—, —CONH— and —CO—, and R ⁹ represents a steroid skeleton, A monovalent organic group having a group selected from a fluoromethyl group and a fluoro group or an alkyl group having 6 to 30 carbon atoms is shown.)

(Wherein R ¹⁰ represents a hydrocarbon group having 1 to 12 carbon atoms, and a plurality of R ¹⁰ may be the same or different, p is an integer of 1 to 3, and q is 1 to 20) Is an integer.)
And compounds represented by the following formulas (10) to (14). These diamine compounds can be used alone or in combination of two or more.

(In the formula, y is an integer of 2 to 12, and z is an integer of 1 to 5.)
Among these, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 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, 1,4-cyclohexanediamine 4,4′-methylenebis (cyclohexylamine), 1,4-bis (4-amino) Enoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, compounds represented by the above formulas (10) to (14), 2,6-diaminopyridine, 3,4-diaminopyridine, 2 1,4-diaminopyrimidine, 3,6-diaminoacridine, a compound represented by the following formula (15) among the compounds represented by the above formula (III), and the following formula among the compounds represented by the above formula (IV) Of the compound represented by (16) and the compound represented by the above formula (V), compounds represented by the following formulas (17) to (25) are preferred.

<Synthesis of polyamic acid>
The proportion of tetracarboxylic dianhydride and diamine used in the polyamic acid synthesis reaction is 0.5 to 2 equivalents of tetracarboxylic dianhydride acid anhydride group to 1 equivalent of amino group of diamine. The ratio is preferably, more preferably 0.7 to 1.2 equivalent.
The polyamic acid synthesis reaction is preferably performed in an organic solvent under a temperature condition of −20 ° C. to 150 ° C., more preferably 0 to 100 ° C.

  Here, the organic solvent is not particularly limited as long as it can dissolve the synthesized polyamic acid. For example, 1-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, 3- Amide solvents such as butoxy-N, N-dimethylpropanamide, 3-methoxy-N, N-dimethylpropanamide, 3-hexyloxy-N, N-dimethylpropanamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea And aprotic polar solvents such as hexamethylphosphotriamide; and phenolic solvents such as m-cresol, xylenol, phenol, and halogenated phenol. The amount of organic solvent used (α) is usually such that the total amount (β) of tetracarboxylic dianhydride and diamine compound is 0.1 to 30% by weight based on the total amount (α + β) of the reaction solution. It is preferable that the amount is small.

  In addition, the said organic solvent can use together the alcohol, ketone, ester, ether, halogenated hydrocarbon, hydrocarbon, etc. which are poor solvents of a polyamic acid in the range in which the polyamic acid to produce | generate does not precipitate. Specific examples of such poor solvents include, 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 methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, malon Acid diethyl, 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 monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene, isoamylpropionate, isoamylisobutyrate, diisopentyl A Or the like can be mentioned Le.

  As described above, a reaction solution obtained by dissolving polyamic acid is obtained. Then, the reaction solution is poured into a large amount of poor solvent to obtain a precipitate, and the precipitate is dried under reduced pressure, or the reaction solution is distilled off under reduced pressure with an evaporator to obtain a polyamic acid. In addition, the polyamic acid can be purified by performing the step of dissolving the polyamic acid again in an organic solvent and then precipitating with a poor solvent, or the step of distilling the reaction solution under reduced pressure with an evaporator once or several times. it can.

<Dehydration ring closure reaction>
The polyimide constituting the liquid crystal aligning agent of the present invention can be synthesized by dehydrating and ring-closing part or all of the polyamic acid composed of the repeating unit represented by the above formula (A). In the polyimide used in the present invention, the ratio of repeating units having an imide ring in all repeating units (hereinafter also referred to as “imidation ratio”) is preferably 40 mol% or more, more preferably 50 mol% or more. By using a polymer having an imidization ratio of 40 mol% or more, a liquid crystal aligning agent capable of forming a liquid crystal alignment film having a short afterimage erasing time can be obtained.

The polyamic acid is dehydrated and closed by (i) a method of heating the polyamic acid, or (ii) dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring-closing catalyst to this solution, and heating as necessary. By the method.
The reaction temperature in the method of heating the polyamic acid (i) is preferably 50 to 200 ° C, more preferably 60 to 170 ° C. When the reaction temperature is less than 50 ° C., the dehydration ring-closing reaction does not proceed sufficiently, and when the reaction temperature exceeds 200 ° C., the molecular weight of the imidized polymer obtained may decrease.

  On the other hand, in the method (ii) of adding a dehydrating agent and a dehydrating ring-closing catalyst to the polyamic acid solution, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride is used as the dehydrating agent. Can do. The amount of the dehydrating agent used depends on the desired imidization ratio, but is preferably 0.01 to 20 mol per 1 mol of the polyamic acid repeating unit. Moreover, as a dehydration ring closure catalyst, tertiary amines, such as a pyridine, a collidine, a lutidine, a triethylamine, can be used, for example. However, it is not limited to these. The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. The imidation rate can be increased as the amount of the above dehydrating agent and dehydrating ring-closing agent increases. In addition, as an organic solvent used for dehydration ring closure reaction, the organic solvent illustrated as what is used for the synthesis | combination of a polyamic acid can be mentioned. And 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 obtained polyimide can be refine | purified by performing operation similar to the purification method of polyamic acid with respect to the reaction solution obtained in this way.

<End-modified polymer>
The polyamic acid (including the specific polyamic acid) and the polyimide (including the specific polyimide) used in the present invention may be of a terminal-modified type having a controlled molecular weight. By using this terminal-modified polymer, the coating characteristics of the liquid crystal aligning agent can be improved without impairing the effects of the present invention. Such a terminal-modified polymer can be synthesized by adding an acid monoanhydride, a monoamine compound, a monoisocyanate compound or the like to the reaction system when synthesizing a polyamic acid. Here, as the acid monoanhydride, for example, maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride , N-hexadecyl succinic anhydride and the like. Examples of monoamine compounds include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, and n-undecylamine. N-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine, etc. Can do. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

<Solution viscosity of polymer>
Each of the polyamic acid and polyimide obtained as described above preferably has a viscosity of 20 to 800 mPa · s, and has a viscosity of 30 to 500 mPa · s, when a 10% solution is obtained. It is more preferable that
In addition, the solution viscosity (mPa * s) of the polymer was measured at 25 degreeC using the E-type rotational viscometer about the solution diluted to 10% of solid content concentration using the predetermined | prescribed solvent.

[Liquid crystal aligning agent]
The liquid crystal aligning agent of this invention is comprised by the said polyamic acid, a polyimide, and a specific compound being normally dissolved and contained in the organic solvent.
The temperature at the time of preparing the liquid crystal aligning agent of this invention becomes like this. Preferably it is 0 to 200 degreeC, More preferably, it is 20 to 60 degreeC.
As an organic solvent which comprises the liquid crystal aligning agent of this invention, the solvent illustrated as what is used for the synthesis reaction of a polyamic acid can be mentioned. Moreover, the poor solvent illustrated as what can be used together in the case of the synthesis reaction of a polyamic acid can also be selected suitably, and can be used together.

  Particularly preferable organic solvents used in the liquid crystal aligning agent of the present invention include, for example, 1-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, 4 -Hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, 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 Coal dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, 3-butoxy-N, N-dimethylpropanamide, 3-methoxy-N, N-dimethylpropanamide 3-hexyloxy-N, N-dimethylpropanamide diethyl carbitol, ethyl carbitol acetate, butyl carbitol, triethylene glycol dimethyl ether, isoamyl isobutyrate, diisopentyl ether and the like. Of these, 3-butoxy-N, N-dimethylpropanamide, 3-methoxy-N, N-dimethylpropanamide, and 3-hexyloxy-N, N-dimethylpropanamide exhibit particularly good printability. preferable.

  The solid content concentration in the liquid crystal aligning agent of the present invention is selected in consideration of viscosity, volatility, etc., but is preferably in the range of 1 to 10% by weight. That is, the liquid crystal aligning agent of the present invention is applied to the substrate surface to form a coating film that becomes a liquid crystal alignment film. When the solid content concentration is less than 1% by weight, the coating film thickness is When the solid content concentration exceeds 10% by weight, the film thickness of the coating film becomes excessive and a good liquid crystal alignment film cannot be obtained. In addition, the viscosity of the liquid crystal aligning agent increases, resulting in poor coating characteristics.

The liquid crystal aligning agent of this invention may contain the functional silane containing compound and the epoxy compound from a viewpoint which improves the adhesiveness with respect to the substrate surface within the range which does not impair the target physical property. Examples of such functional silane-containing compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, and N- (2-aminoethyl). -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-amino Propyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl- , 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, etc. can be mentioned. The blending ratio of these other functional silane-containing compounds is preferably 10 parts by weight or less, more preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the total amount of the polymer.
Examples of such epoxy compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and 1,6-hexane. Diol 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′-dia Bruno diphenylmethane, 3- (N-Ariru N Gurishijiru) aminopropyltrimethoxysilane, 3- (N, N-diglycidyl) and aminopropyl trimethoxy silane can be cited. Examples of the epoxy group-containing compound include 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-dibromoneopentylglycol 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, N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenyl ether, 1,4-bis (N, N-diglycidylaminomethyl) cyclohexane, 1,3-bis (N, N -Diglycidylaminomethyl) benzene, 1,4-bis (N, N-diglycidylaminomethyl) benzene, 3- (N-allyl-N-glycidyl) aminopropyltrimethoxysilane, 3- (N, N-diglycidyl) Preferred examples include aminopropyltrimethoxysilane, N, N- diglycidyl-benzylamine, N, N-diglycidyl-aminomethylcyclohexane, and the like. The blending ratio of these glycidylamine type epoxy group-containing compounds is preferably 50 parts by weight or less, more preferably 0.1 to 40 parts by weight, and more preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the polymer. Parts by weight.

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

(1) The liquid crystal aligning agent of the present invention is applied to one surface of a substrate provided with a patterned transparent conductive film by an offset printing method, a spin coating method, or an ink jet printing method, and then the coated surface is heated. To form a coating film. Here, as the substrate, for example, a glass such as float glass or soda glass; a transparent substrate made of a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, or polycarbonate can be used. As a transparent conductive film provided on one surface of the substrate, an NESA film (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ ), etc. For patterning these transparent conductive films, a photo-etching method or a method using a mask in advance is used. When applying the liquid crystal aligning agent, in order to further improve the adhesion between the substrate surface and the transparent conductive film and the coating film, a functional silane-containing compound, a functional titanium-containing compound, or the like is previously applied to the surface of the substrate. You can also The heating temperature after application of the liquid crystal aligning agent is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. The liquid crystal aligning agent of the present invention containing a polyamic acid forms a coating film that becomes an alignment film by removing the organic solvent after coating. It can also be a membrane. The film thickness of the coating film to be formed is, for example, 0.001 to 1 μm, preferably 0.005 to 0.5 μm.

(2) A rubbing process is performed in which the formed coating film surface is rubbed in a certain direction with a roll wound with a cloth made of a fiber such as nylon, rayon, or cotton. Thereby, the orientation ability of liquid crystal molecules is imparted to the coating film to form a liquid crystal orientation film. Further, by partially irradiating the liquid crystal alignment film formed of the liquid crystal alignment agent of the present invention with ultraviolet rays as disclosed in, for example, JP-A-6-222366 and JP-A-6-281937. A resist film is partially formed on the surface of the liquid crystal alignment film that has been subjected to a treatment for changing the pretilt angle or a rubbing treatment as disclosed in JP-A-5-107544, which is different from the previous rubbing treatment. The visibility characteristics of the liquid crystal display element can be improved by removing the resist film after performing the rubbing treatment in the direction and changing the liquid crystal alignment ability of the liquid crystal alignment film.

(3) Two substrates on which the liquid crystal alignment film is formed as described above are manufactured, and the two substrates are separated by a gap (cell gap) so that the rubbing directions in the respective liquid crystal alignment films are orthogonal or antiparallel. ), And the periphery of the two substrates are bonded together using a sealant, and liquid crystal is injected and filled in the cell gap defined by the substrate surface and the sealant, and the injection hole is sealed. A liquid crystal cell is constructed. A polarizing plate is disposed on the outer surface of the liquid crystal cell, that is, on the other surface side of each substrate constituting the liquid crystal cell, and the polarization direction thereof coincides with or is orthogonal to the rubbing direction of the liquid crystal alignment film formed on one surface of the substrate. A liquid crystal display element is obtained by pasting together. Here, as the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used. Examples of the liquid crystal include nematic liquid crystal and smectic liquid crystal. Among them, nematic liquid crystal is preferable. For example, Schiff base liquid crystal, azoxy liquid crystal, biphenyl liquid crystal, phenyl cyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal. Liquid crystals, biphenylcyclohexane liquid crystals, pyrimidine liquid crystals, dioxane liquid crystals, bicyclooctane liquid crystals, cubane liquid crystals, and the like can be used. Further, for these liquid crystals, for example, cholesteric liquid crystals such as cholestyl chloride, cholesteryl nonate, cholesteryl carbonate, and chiral agents such as those sold under the trade names “C-15” and “CB-15” (manufactured by Merck). Etc. can also be used. Furthermore, a ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate can also be used. Further, as a polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing film or an H film in which a polarizing film called an H film that absorbs iodine while sandwiching and stretching polyvinyl alcohol is sandwiched between cellulose acetate protective films. The polarizing plate which consists of itself can be mentioned.
Here, as the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

[Printability evaluation]
A 127 mm (D) × 127 mm (W) × 1.1 mm (H) glass substrate having an ITO film formed on the entire surface of one side is prepared, and a liquid crystal alignment film coating printer (Nissha Printing Co., Ltd.) is prepared on this glass substrate. The liquid crystal aligning agent obtained in the above experiment was filtered with a microfilter having a pore diameter of 0.2 μm using an Angstromer S-40L) and then applied to the transparent electrode surface. It dried with the hotplate contact | adhesion type preliminary dryer set to 80 degreeC, and baked at 200 degreeC for 10 minute (s), and formed the liquid crystal aligning film on the glass substrate with an ITO film | membrane. The obtained alignment film was evaluated for unevenness by visual observation, and a film having no unevenness was marked with ◯, and a film with unevenness was marked with x.

[Voltage holding ratio]
A voltage of 5 V was applied to the liquid crystal display element with an application time of 60 microseconds and a span of 167 milliseconds, and then the voltage holding ratio after 167 milliseconds from release of application was measured. The measuring apparatus used was VHR-1 manufactured by Toyo Corporation.

[Burn-in test]
A cell having an ITO electrode as shown in FIG. 1 was produced. A DC voltage of 6.0 V was applied to the electrode A, and a DC voltage of 0.5 V was applied to the electrode B at room temperature for 24 hours. After releasing the stress, a DC voltage of 0.1 to 5.0 V was applied to the electrodes A and B in increments of 0.1 V. The image sticking characteristics were determined based on the luminance difference between the electrodes A and B at each voltage. When the brightness difference was large, it was judged that the burn-in characteristic was bad. The case where no seizure was observed was marked with ◯, the case where seizure was weakly generated was marked with Δ, and the case where seizure was strong was marked with x.

Synthesis example 1
The following reaction was performed according to the following procedure under a nitrogen atmosphere.

Benzenethiol 22 g (0.2 mol), 4,4′-dibromobiphenyl 31.2 g (0.1 mol), potassium carbonate 69.1 g (0.5 mol), and DMF 500 ml were mixed in a three-necked flask equipped with a Dimroth condenser. . Heated to 60 ° C. and stirred for 8 hours. The reaction solution was cooled, and the reaction solution was poured into 2 L of 10% aqueous hydrochloric acid. Further, NH ₄ PF ₆ (0.2 mol) was added and stirred for 2 hours. The precipitated solid was separated by filtration, and the solid was washed with water and diethyl ether in this order.
Further purification was performed by column chromatography to obtain 27.8 g of the target compound 1 (compound A).

Synthesis example 2
The following reaction was performed by the following procedure under a nitrogen atmosphere.

In a three-necked flask equipped with a Dimroth condenser, 31 g (0.2 mol) of p-nitrobenzenethiol, 31.2 g (0.1 mol) of 4,4′-dibromobiphenyl, 69.1 g (0.5 mol) of potassium carbonate, and 500 ml of DMF were mixed. Mixed. Heated to 60 ° C. and stirred for 8 hours. The reaction solution was cooled, and the reaction solution was poured into 2 L of 10% aqueous hydrochloric acid. Further, 32.6 g (0.2 mol) of NH ₄ PF ₆ was added and stirred for 2 hours. The precipitated solid was separated by filtration, and the solid was washed with water and diethyl ether in this order.
Further purification was performed by column chromatography to obtain 32.2 g of the target compound 2.

  Synthesis example 3

30 g (0.065 mol) of Compound 2 was dissolved in 400 ml of ethanol, 0.3 g of 5 wt% palladium-carbon catalyst and 5.0 g (0.1 mol) of hydrazine monohydrate were added, and the mixture was heated to reflux for 6 hours. The reaction solution was poured into a large excess of water, and the precipitate was filtered off. The obtained solid was further recrystallized from ethanol to obtain 16.9 g of the target compound 3 .

  Synthesis example 4

  15 g (0.037 mol) of Compound 3, 200 ml of DMSO, and 41.4 g (0.3 mol) of potassium carbonate were mixed. After cooling this solution in an ice bath, 27.8 g (0.3 mol) of epichlorohydrin in 200 ml of DMSO solution was added dropwise. After completion of the dropping, the temperature was returned to room temperature, followed by stirring for 48 hours. The reaction solution was filtered, the filtrate was concentrated with a rotary evaporator, and the epichlorohydrin added excessively was removed with a vacuum pump. The obtained crude product was diluted by adding 300 ml of toluene, and the liquid was washed 4 times with 300 ml of distilled water. Sodium sulfate was added and allowed to stand overnight, then the sodium sulfate was filtered off and the solvent was removed by a rotary evaporator. The obtained crude product was purified by silica gel column chromatography to obtain 16.2 g of compound 4 (specific compound B).

Synthesis example 5
(Synthesis of specific polyamic acid A)
1.84 g (0.04 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 16 g (0.04 mol) of compound 3 as N-methyl-2 as a diamine compound -It was made to melt | dissolve in 180 g of pyrrolidone, and it was made to react at 40 degreeC for 3 hours. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 15 hours to obtain 12 g of polyamic acid (this is referred to as “specific polyamic acid A”).

Synthesis Example 6
2,3,5-tricarboxycyclopentylacetic acid dianhydride 112.09 g (0.50 mol) and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5 as tetracarboxylic dianhydride (Tetrahydro-2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione 157.15 g (0.50 mol), p-phenylenediamine 93.54 g (0 .865 mol), 3,3 ′-(tetramethyldisiloxane-1,3-diyl) bis (propylamine) 24.85 g (0.10 mol), and 3,6-bis (4-aminobenzoyloxy) 12.86 g (0.02 mol) of cholestan and 8.09 g (0.03 mol) of n-octadecylamine as monoamine were added to N-methyl-2-pyrrolidone 4,500. It was dissolved in g and reacted at 60 ° C. for 6 hours. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 15 hours to obtain 380 g of a polyamic acid having a logarithmic viscosity of 0.80 dl / g. 30 g of the resulting polyamic acid was dissolved in 570 g of N-methyl-2-pyrrolidone, 23.4 g of pyridine and 18.1 g of acetic anhydride were added, and dehydration was carried out at 110 ° C. for 4 hours, followed by precipitation, washing, The pressure was reduced to obtain 18.6 g of polyimide (referred to as “polyimide (A-1)”).

Synthesis example 7
224.17 g (1.0 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride, 108.14 g (1.0 mol) of p-phenylenediamine as a diamine compound, and cholesteryl- 7.842 g (0.015 mol) of 3,5-diaminobenzoate was dissolved in 4,500 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 15 hours to obtain 400 g of polyamic acid having a logarithmic viscosity of 0.75 dl / g. 30 g of the resulting polyamic acid was dissolved in 570 g of N-methyl-2-pyrrolidone, 23.4 g of pyridine and 18.1 g of acetic anhydride were added, and dehydration was carried out at 110 ° C. for 4 hours, followed by precipitation, washing, The pressure was reduced to obtain 19.2 g of polyimide (referred to as “polyimide (A-2)”).

Synthesis Example 8
196.12 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 2,2′-dimethyl-4,4′-diaminobiphenyl 212 as diamine compound .3 g (1.0 mol) was dissolved in 4,500 g of N-methyl-2-pyrrolidone and reacted at 40 ° C. for 3 hours. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 15 hours to obtain 390 g of polyamic acid (this is referred to as “polyamic acid (I-1)”).

Example 1
The polyimide (A-1) obtained in Synthesis Example 6 and the polyamic acid (I-1) obtained in Synthesis Example 8 were mixed with γ-butyrolactone so that polyimide: polyamic acid = 20: 80 (weight ratio). / N-methyl-2-pyrrolidone / butyl cellosolve mixed solvent (weight ratio 71/17/12) to dissolve N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane as a polymer 100 2 parts by weight and 10 parts by weight of Compound 4 to the polymer 100 were added to prepare a solution having a solid content concentration of 3.5% by weight and a solution having a weight of 6.0% by weight. Each solution was sufficiently stirred and then filtered using a filter having a pore size of 1 μm to prepare the liquid crystal aligning agent of the present invention.

Among the liquid crystal aligning agents, a solution having a solid content concentration of 3.5% by weight is applied on a transparent conductive film made of an ITO film provided on one surface of a glass substrate having a thickness of 1 mm using a spinner (number of rotations: 2,500 rpm, coating time: 1 minute) and dried at 200 ° C. for 1 hour to form a film having a dry film thickness of 0.08 μm. A rubbing machine having a roll in which a rayon cloth was wound around this film was subjected to a rubbing treatment at a roll rotation speed of 400 rpm, a stage moving speed of 3 cm / second, and a hair foot pushing length of 0.4 mm. The liquid crystal alignment film-coated substrate was dipped in isopropyl alcohol for 1 minute and then dried on a hot plate at 100 ° C. for 5 minutes. Next, after applying an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm to the outer edges of the pair of transparent electrodes / transparent electrode substrates having the liquid crystal alignment film of the liquid crystal alignment film coated substrate, the liquid crystal alignment film The adhesive was cured by overlapping and pressing so that the surfaces were opposed. Next, a nematic liquid crystal (MLC-6221, manufactured by Merck & Co., Inc.) is filled between the substrates through the liquid crystal injection port, and then the liquid crystal injection port is sealed with an acrylic photo-curing adhesive, and polarizing plates are formed on both sides of the substrate. Were laminated to prepare a liquid crystal display element. The voltage holding ratio evaluation and burn-in evaluation of the obtained liquid crystal display element were performed according to the method described above.
Using a solution having a solid content concentration of 6.0% by weight, printability was evaluated according to the method described above.

Example 2
The polyimide (A-2) obtained in Synthesis Example 7 is dissolved in an N-methyl-2-pyrrolidone / butyl cellosolve mixed solvent (weight ratio 50/50), and N, N, N ′, N′-tetraglycidyl is dissolved. 2 parts by weight of -4,4'-diaminodiphenylmethane is added to 100 parts by weight of polyimide (A-2), and 10 parts by weight of Compound 4 (specific compound B) is added to 100 parts by weight of polyimide (A-2). A solution having a solid concentration of 3.5% by weight and a solution having a solid content of 6.0% by weight were prepared. Each solution was sufficiently stirred and then filtered using a filter having a pore size of 1 μm to prepare the liquid crystal aligning agent of the present invention. The method for producing the liquid crystal display element, the method for evaluating the liquid crystal display element, and the method for evaluating the orientation agent printability were performed in the same manner as in Example 1.

Example 3 (Reference Example)
The polyimide (A-1) and the specific polyamic acid A obtained in Synthesis Example 6 were mixed with γ-butyrolactone / N-methyl-2-pyrrolidone so that polyimide: specific polyamic acid A = 20: 80 (weight ratio). / Butyl cellosolve mixed solvent (weight ratio 71/17/12), N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane is 100 parts by weight in total of polyimide and specific polyamic acid A 2 parts by weight were added to the solution to prepare a solution having a solid content concentration of 3.5% by weight and a solution having a solid content of 6.0% by weight. Each solution was sufficiently stirred and then filtered using a filter having a pore size of 1 μm to prepare the liquid crystal aligning agent of the present invention.

Comparative Examples 1-4
The polyimide, polyamic acid, and the specific compound were prepared in the same procedure as in Example 1 using the materials shown in Table 1.

Explanatory drawing of the cell with the ITO electrode created for the burn-in test.

Claims (3)

A mixture of a polyamic acid comprising a repeating unit represented by the following formula (A) and a polyimide comprising a repeating unit represented by the following formula (B), a polyimide comprising a repeating unit represented by the following formula (B), and the following formula ( A liquid crystal aligning agent comprising the compound represented by 1).

(Wherein P ¹ is a tetravalent organic group and Q ¹ is a divalent organic group.)

(Wherein P ² is a tetravalent organic group and Q ² is a divalent organic group.)

(Wherein two ^{R 1} is either hydrogen atom, Y is -S -, - NH -, - O -, - CH 2 - or a single bond, ^{X 1} and ^{X 2} are each independently And any of the following structures.)

(In the formula, Z ¹ , Z ² and Z ³ are diglycidylamino groups.) ^2. The liquid crystal aligning agent according to claim 1, wherein P ¹ in the formula (A) and P ² in the formula (B) are both derived from 2,3,5-tricarboxycyclopentylacetic acid dianhydride. The liquid crystal display element characterized by including the liquid crystal alignment film obtained from the liquid crystal aligning agent according to claim 1 or 2.

Images