JP4978434B2 - Liquid crystal aligning agent and liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal aligning agent used for forming a liquid crystal alignment film of a liquid crystal display element. More specifically, the present invention relates to a liquid crystal aligning agent and a liquid crystal display element that provide a liquid crystal alignment film having good electrical characteristics and good printability.

Currently, as a liquid crystal display element, a liquid crystal alignment film made of polyamic acid, polyimide, or the like is formed on the surface of a substrate on which a transparent conductive film is provided 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 Patent Document 1 and Non-Patent Document 1, a vertical alignment type liquid crystal display element called an MVA method is proposed in which protrusions are formed on an ITO film to control the alignment direction of the liquid crystal. ing. 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 provide a liquid crystal aligning agent that maintains a voltage holding ratio, reduces accumulated charges, and has excellent printability. Another object of the present invention is to provide a liquid crystal display device having a liquid crystal alignment film.

  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.
This is achieved by a liquid crystal aligning agent characterized by containing a compound represented by the following formula (1) (hereinafter sometimes referred to as “specific compound”).

Here, R _{1 to} R ₄ are each independently a hydrogen atom or an aliphatic group, preferably an aliphatic group containing an epoxy group, and R _{5 to} R ₉ are a hydrogen atom, an alkyl group, an alkoxy group or an aromatic group. And A is a hydrogen atom or an aliphatic group.
R _{1 to} R ₄ in the above formula (1) are each independently an aliphatic group containing an epoxy group, and more preferably, A is an aliphatic group containing a hydrogen atom or an epoxy group.

  In addition, according to the present invention, the above-mentioned objects and advantages of the present invention are, secondly, a polyamic acid comprising the specific compound described above, a repeating unit represented by the following formula (I-1), and (I-2) And at least one polymer selected from the group consisting of polyimides consisting of repeating units represented by formula (1).

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

(Where P ² is a tetravalent organic group and Q ² is a divalent organic group.)
At least a part of tetracarboxylic dianhydride used for the synthesis of the polyamic acid composed of the repeating unit represented by the formula (I-1) and the polyimide composed of the repeating unit represented by (I-2) is 2, 3, 5-Tricarboxycyclopentylacetic acid dianhydride is preferred.

  According to the present invention, the above objects and advantages of the present invention are thirdly achieved by a liquid crystal display device comprising a liquid crystal alignment film obtained using the liquid crystal aligning agent of the present invention. .

  Hereinafter, the present invention will be described in detail.

  The liquid crystal aligning agent of the present invention is constituted by dissolving a specific compound and preferably at least one polymer selected from the group consisting of polyamic acid and polyimide in an organic solvent.

[Specific compound 1]
In the formula (1), R _{5 to} R ₉ are each independently a hydrogen atom, an alkyl group, an alkoxy group or an aromatic group, and are not particularly limited. Among them, the alkyl group and the alkoxyl group are preferably carbon atoms. These are an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms. Examples of the alkyl group contained in the alkyl group and the alkoxy group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a 2-methyl-propyl group, a 3-methyl-propyl group, and an n-pentyl group. Group and n-hexyl group. Moreover, as an aromatic group, a phenyl group or a naphthyl group is mentioned, for example. R _{1 to} R ₄ and A each independently represent a hydrogen atom or an aliphatic group. The aliphatic group is preferably an aliphatic group containing an aliphatic group having 1 to 4 carbon atoms or an epoxy group. Specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, and a glycidyl group.

  Preferred compounds represented by formula (1) are as follows.

[Polyamic acid]
<Tetracarboxylic dianhydride>
The tetracarboxylic dianhydride used for the synthesis of the polyamic acid comprising the repeating unit represented by the above formula (I-1) and giving the tetravalent organic group P ¹ includes an alicyclic tetracarboxylic dianhydride, Examples include aliphatic tetracarboxylic dianhydrides and aromatic tetracarboxylic dianhydrides. Of these, aliphatic 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, 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, 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-oxabicyclo [3.2.1] Octane-2,4-dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′-dione), 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene -1,2-dicarboxylic acid anhydride, 3,5,6-tricarboxy-2-carboxynorbornane-2: 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1 0.0 ^2,6 ] undecane-3,5,8,10-tetrao , Compounds represented by the following formulas (I) and (II),

(Wherein R ¹ and R ³ represent a divalent organic group having an aromatic ring, R ² and R ⁴ represent a hydrogen atom or an alkyl group, and a plurality of R ² and R ⁴ are 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′-perfluoroisopropylidene diphthalic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2 , 2 ′, 3,3′-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 (1) to (4). These may be 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-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- Xahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8- Methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5 8-Dimethyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, bicyclo [2.2.2] -oct-7-ene -2,3,5,6-tetracarboxylic dianhydride, 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3 '-(tetrahydrofuran-2', 5 ' -Dione), 5- (2,5-dioxotetrahydro-3-fura ) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxynorbornane-2: 3,5: 6-dianhydride, 4,9- Dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone, among the compounds represented by the above formula (I), the following formulas (5) to (7) An alicyclic tetracarboxylic dianhydride such as a compound represented by the following formula (8) among the compounds represented by the above formula (II) and the alicyclic tetracarboxylic dianhydride such as a compound represented by: From the standpoint of achieving good liquid crystal orientation. Particularly preferred are 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5- Tricarboxycyclopentyl acetic acid 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-dianhydride, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2 -C] furan-1,3- ON, 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3 '-(tetrahydrofuran-2', 5'-dione), 5- (2,5-dioxotetrahydro -3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxynorbornane-2: 3,5: 6-dianhydride, 4 , 9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone and compounds represented by the following formula (5).

Among the other tetracarboxylic dianhydrides other than the alicyclic tetracarboxylic dianhydrides, for example, butanetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4, 4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 1, 4,5,8-naphthalenetetracarboxylic dianhydride and the like.
Of these tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, especially 2,3,5-tricarboxycyclopentylic dianhydride, are at least one part, preferably 50, of all tetracarboxylic dianhydrides. It is desirable to be at least mol%.

<Diamine>
Examples of the diamine that is used for the synthesis of the polyamic acid composed of the repeating unit represented by the above formula (I-1) and gives the divalent organic group Q ¹ include p-phenylenediamine, m-phenylenediamine, and 4,4. '-Diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenylsulfone, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3 '-Dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminobenzanilide, 4,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 2,2'-ditrifluoromethyl-4,4'- Diaminobiphenyl, 3,3′-ditrifluoromethyl-4,4′-diaminobiphenyl, 5-amino-1- (4′-aminophenyl) ) -1,3,3-trimethylindane, 6-amino-1- (4′-aminophenyl) -1,3,3-trimethylindane, 3,4′-diaminodiphenyl ether, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-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) Nyl) -10-hydroanthracene, 2,7-diaminofluorene, 9,9-dimethyl-2,7-diaminofluorene, 9,9-bis (4-aminophenyl) fluorene, 4,4′-methylene-bis ( 2-chloroaniline), 2,2 ′, 5,5′-tetrachloro-4,4′-diaminobiphenyl, 2,2′-dichloro-4,4′-diamino-5,5′-dimethoxybiphenyl, 3 , 3′-dimethoxy-4,4′-diaminobiphenyl, 1,4,4 ′-(p-phenyleneisopropylidene) bisaniline, 4,4 ′-(m-phenyleneisopropylidene) bisaniline, 2,2′-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 4, '- bis [(4-amino-2-trifluoromethyl) phenoxy] - aromatic diamines such as octafluoro biphenyl;
1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1 , 4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindanylene methylenediamine, tricyclo [6.2.1.0 ^2,7 ] -undecylenedimethyldiamine, 4 Aliphatic and cycloaliphatic 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-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, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl -3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N, N'-di (4-aminophenyl) -benzidine, N, N'-di (4-aminophenyl) -N, N A diamine having two primary amino groups and a nitrogen atom other than the primary amino group in the molecule, such as'-dimethyl-benzidine; Such as diamino organosiloxane represented the like. These diamines can be used alone or in combination of two or more.

(In the formula, R ⁵ represents a hydrocarbon group having 1 to 12 carbon atoms, and a plurality of R ⁵ may be the same or different, p is an integer of 1 to 3, and q is 1 to 20) Is an integer.)
Of these, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 2,2′-dimethyl-4,4′-diaminobiphenyl, 1,5-diaminonaphthalene, 2,7 -Diaminofluorene, 9,9-dimethyl-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-pheny Range isopropylidene) bisaniline, 4,4 ′-(m-phenylenediisopropylidene) bisaniline, 1,4-cycl Rhohexanediamine, 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, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole, N -Phenyl-3,6-diaminocarbazole, N, N'-di (4-aminophenyl) -benzidine, N, N'-di (4-aminophenyl) -N, N'-dimethyl-benzidine and the like are preferable.

Moreover, the polyimide which consists of a repeating unit shown by said Formula (I-2) can be manufactured by carrying out dehydration ring closure of the polyamic acid which consists of a repeating unit shown by said Formula (I-1).
For the liquid crystal alignment agent of the present invention has a pretilt angle expressing the above formula (I-1) and Q ^1, part Q ² 'or all the following formulas in each of (I-2) (Q- 1 ) And at least one group represented by the following formula (Q-2). That is, a diamine having a group represented by the following formula (Q-1) or the following formula (Q-2) (hereinafter sometimes referred to as “specific diamine”) is used. These may be used alone or in combination of two or more.

(In the formula, X is a single bond, —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—, —S— or an arylene group, and R ⁶ has 10 carbon atoms. An alkyl group of -20, 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 to 20 carbon atoms.)

(In the formula, X is a single bond, —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—, —S— or an arylene group, and R ⁷ has 4 carbon atoms. It is a divalent organic group having an alicyclic skeleton of ˜40.)
In the above formula (Q-1), examples of the alkyl group having 10 to 20 carbon atoms represented by R ⁶ include n-decyl group, n-dodecyl group, n-pentadecyl group, n-hexadecyl group, n- An octadecyl group, n-eicosyl group, etc. are mentioned. Examples of the organic group having an alicyclic skeleton having 4 to 40 carbon atoms represented by R ⁶ in the above formula (Q-1) and R ⁷ in the above formula (Q-2) include cyclobutane and cyclopentane. Groups having an alicyclic skeleton derived from cycloalkane such as cyclohexane and cyclodecane; groups having a steroid skeleton such as cholesterol and cholestanol; groups having a bridged alicyclic skeleton such as norbornene and adamantane. Among these, a group having a steroid skeleton is particularly preferable. The organic group having an alicyclic skeleton may be a group substituted with a halogen atom, preferably a fluorine atom, or a fluoroalkyl group, preferably a trifluoromethyl group.

Furthermore, examples of the group having 6 to 20 carbon atoms represented by R ⁶ in the formula (Q-1) include carbon atoms such as an n-hexyl group, an n-octyl group, and an n-decyl group. A linear alkyl group having 6 or more; an alicyclic hydrocarbon group having 6 or more carbon atoms such as a cyclohexyl group or a cyclooctyl group; an organic group such as an aromatic hydrocarbon group having 6 or more carbon atoms such as a phenyl group or a biphenyl group And a group in which part or all of the hydrogen atoms are substituted with a fluoroalkyl group such as a fluorine atom or a trifluoromethyl group.

  X in the formula (Q-1) and the formula (Q-2) is a single bond, -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH-, -S. -Or an arylene group, and examples of the arylene group include a phenylene group, a tolylene group, a biphenylene group, and a naphthylene group. Of these, groups represented by —O—, —COO—, and —OCO— are particularly preferable. Specific examples of the diamine having a group represented by the above formula (Q-1) include dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy- Preferred examples include 2,4-diaminobenzene and compounds represented by the following formulas (9) to (13).

  Specific examples of the diamine having a group represented by the formula (Q-2) include diamines represented by the following formulas (14) to (16).

Of these, particularly preferred are compounds represented by the above formulas (9), (11), (13) and (14).
The use ratio of the specific diamine with respect to the total amount of diamine varies depending on the size of the pretilt angle to be expressed, but in the case of a TN type or STN type liquid crystal display element, 0 to 5 mol%, in the case of a vertical alignment type liquid crystal display element 5 to 100 mol% is preferable.

<Synthesis of polyamic acid>
The ratio of tetracarboxylic dianhydride and diamine used for the polyamic acid synthesis reaction is 0.2 to 2 equivalents of tetracarboxylic dianhydride acid anhydride group to 1 equivalent of amino group of diamine. The ratio is preferably, more preferably 0.3 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 such that the total amount (β) of tetracarboxylic dianhydride and diamine compound is 0.1 to 30% by weight based on the total amount of the reaction solution (α + β). It is preferable that

  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. Further, the polyamic acid can be purified by dissolving the polyamic acid again in an organic solvent and then precipitating it with a poor solvent, or performing the step of evaporating under reduced pressure with an evaporator once or several times.

<Dehydration ring closure reaction>
The polyimide constituting the liquid crystal aligning agent of the present invention can be synthesized by dehydrating and ring-closing some or all of the polyamic acid. 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 40 mol% or 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 imidization rate can be determined by the following method.

Method for measuring imidation rate of imidized polymer After imidized polymer was dried 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 substance. It can obtain | require by the type | formula shown by (ii).
Imidation ratio (%) = (1-A ¹ / A ² × α) × 100 ------ (ii)
A ¹ : NH group proton-derived peak area (10 ppm)
A ² : Peak area derived from other protons α: Number ratio of other protons to one proton of NH group in the precursor (polyamic acid) of the polymer The dehydration ring closure of the polyamic acid is (i) heating the polyamic acid Or (ii) a method in which polyamic acid is dissolved in an organic solvent, a dehydrating agent and a dehydrating ring-closing catalyst are added to this solution, and heating is performed as necessary.
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 and polyimide used in the present invention may be of a terminal modified type with 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>
The polymer used in the aligning agent of the present invention preferably has a viscosity of 20 to 800 mPa · s, and has a viscosity of 30 to 500 mPa · s, when a 10% by weight solution is obtained. It is more preferable.
The solution viscosity (mPa · s) of the polymer was measured at 25 ° C. using an E-type rotational viscometer for a solution diluted to a solid content concentration of 10% by weight using a predetermined solvent.

[Liquid crystal aligning agent]
The liquid crystal aligning agent of the present invention is usually constituted by dissolving the above-mentioned specific compound and preferably further the above-mentioned polymer and other components optionally added in an 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.

  Examples of the organic solvent constituting the liquid crystal aligning agent of the present invention include 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 dimethyl Ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, 3-butoxy-N, N-dimethyl Propanamide, 3-methoxy-N, N-dimethylpropanamide, 3-hexyloxy-N, N-dimethylpropanamide and the like can be mentioned. These can be used alone or in admixture of two or more. 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 particularly preferable solid content concentration range varies depending on the method used when the liquid crystal aligning agent is applied to the substrate. For example, when the spinner method is used, the range of 1.5 to 4.5% by weight is particularly preferable. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by weight, and thereby the solution viscosity is in the range of 12 to 50 mPa · s. In the case of the ink jet method, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by weight, and thereby the solution viscosity is in the range of 3 to 15 mPa · s.

  The liquid crystal aligning agent of the present invention may contain an epoxy compound other than the functional silane-containing compound and the specific compound from the viewpoint of improving the adhesion to the substrate surface within a range not impairing the target physical properties. 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. 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 ′ Diaminodiphenylmethane, N, N, -diglycidyl-benzylamine, N, N-diglycidyl-aminomethylcyclohexane, 3- (N-allyl-N-glycidyl) aminopropyltrimethoxysilane, 3- (N, N-diglycidyl) aminopropyltri And methoxysilane. The blending ratio of these functional silane-containing compounds and epoxy group-containing compounds is preferably 40 parts by weight or less, more preferably 30 parts by weight or less, with respect to 100 parts by weight of the polymer.

<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. Form a coating film. Here, as the substrate, for example, glass such as float glass or soda glass; a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, alicyclic polyolefin, or the like 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. Can be used. 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 After applying the liquid crystal aligning agent, preheating (pre-baking) is preferably performed for the purpose of preventing dripping of the applied aligning agent. The pre-baking temperature is preferably 30 to 200 ° C, more preferably 40 to 150 ° C, and particularly preferably 40 to 100 ° C. Thereafter, a baking (post-baking) step is performed for the purpose of completely removing the solvent and heat imidizing the polyamic acid. The firing (post-bake) temperature is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. In addition, 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, but further proceeds with dehydration ring closure by further heating, and is further imidized. It can also be set as a coating film. The film thickness of the formed coating film is preferably 0.001-1 μm, more preferably 0.005-0.5 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, the other surface 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.

  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 close contact type preliminary dryer set to 80 degreeC, and baked for 60 minutes at 200 degreeC, and formed the liquid crystal aligning film on the glass substrate with an ITO film | membrane. The unevenness of the obtained alignment film was visually evaluated. A sample in which no unevenness was observed was marked with ◯, and a sample with unevenness was marked with ×.

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

[Burn-in test]
A cell having the ITO electrode shown in FIG. 1 was produced. A DC voltage of 10.0 V was applied to the electrode A, and a DC voltage of 0.5 V was applied to the electrode B for 24 hours at room temperature. 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 luminance difference was large, it was judged that the image sticking characteristic was bad.
The case where no seizure was observed was marked with ◯, and the case where seizure occurred was marked with x.

<Synthesis of specific compounds>
Synthesis example 1
In a 500 ml four-necked flask in a nitrogen atmosphere, 20 ml of toluene, 0.42 g (0.0018 mol) of palladium (II) acetate and 1.5 g (0.0075 mol) of tert-butylphosphine were added and stirred for several minutes. 100 ml of a toluene solution of 22.2 g (0.094 mol) of dibromobenzene was dropped, and the mixture was further stirred for 10 minutes.
Next, after adding 200 ml of a toluene solution of 42.0 g (0.196 mol) of 4-amino-4′-nitrobiphenyl, 15.86 g (0.165 mol) of sodium-tert-butoxide was added, and the mixture was heated to reflux for 4 hours. Reacted. After completion of the reaction, water was added to the container and extracted with diethyl ether. After dehydration with sodium sulfate, sodium sulfate was filtered off, and the solvent was removed with a rotary evaporator. The crude product was purified by silica gel column chromatography to obtain compound (1).

Synthesis example 2
In a 500 ml three-necked flask, 5 g (9.95 mmol) of compound (1), 13 g (199 mmol) of zinc, 2.1 g (40 mmol) of ammonium chloride, 150 ml of ethanol and 15 ml of water were mixed. This solution was heated to reflux and reacted for 7 hours. The reaction solution was filtered, and the filtrate was added dropwise to 1 L of water. The precipitated solid was filtered off and dried to obtain a crude product. The crude product was purified by silica gel column chromatography to obtain the specific compound (A-1).

Synthesis example 3
In a 200 ml three-necked flask, 3 g (6.78 mmol) of the specific compound (A-1), 40 ml of DMSO, and 8.75 g (54.2 mmol) of potassium carbonate were mixed. After cooling this solution in an ice bath, epichlorohydrin 5.0 g (54.2 mmol) DMSO solution 40 ml 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 100 ml of toluene, and the liquid was washed 4 times with 100 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 the specific compound (A-2).

Polyimide synthesis example 1
2,3,5-tricarboxycyclopentyl acetic acid dianhydride 112 g (0.50 mol) and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro) as tetracarboxylic dianhydride -2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione 157 g (0.50 mol), p-phenylenediamine 96 g (0.89 mol) as the diamine compound, 3 , 3 ′-(tetramethyldisiloxane-1,3-diyl) bis (propylamine) 25 g (0.10 mol) and 3,6-bis (4-aminobenzoyloxy) cholestane 13 g (0.020 mol) Then, 8.1 g (0.030 mol) of n-octadecylamine as a monoamine was dissolved in 960 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours. It was. A small amount of the resulting polyamic acid solution was taken, NMP was added, and the viscosity was measured with a solution having a solid content concentration of 10% by weight. As a result, it was 60 mPa · s. Next, 2,700 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 396 g of pyridine and 409 g of acetic anhydride were added, and dehydration ring closure was performed at 110 ° C. for 4 hours. After the imidization reaction, the solvent in the system was replaced with new γ-butyrolactone (the pyridine and acetic anhydride used for the imidization reaction were removed from the system in this operation), and the solid content concentration was 15% by weight. About 2,000 g of an imidized polymer (referred to as “polyimide (A-1)”) having a solution viscosity of 70 mPa · s and an imidization ratio of about 95% at a partial concentration of 10% by weight (γ-butyrolactone solution). Got.

Polyimide synthesis example 2
224 g (1.0 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride, 108 g (1.0 mol) of p-phenylenediamine as a diamine compound, and cholesteryl-3,5- 7.8 g (0.015 mol) of diaminobenzoate was dissolved in 3,039 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours to obtain a polyamic acid solution having a solution viscosity of about 260 mPa · s. Next, 2,700 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 396 g of pyridine and 306 g of acetic anhydride were added, and dehydration ring closure was performed at 110 ° C. for 4 hours. After the imidation reaction, the solvent in the system was replaced with new γ-butyrolactone (the pyridine and acetic anhydride used in the imidation reaction were removed from the system in this operation), and the solid content concentration was about 9.0 wt. %, A solid content concentration of 10% by weight (γ-butyrolactone solution), an imidized polymer having a solution viscosity of 250 mPa · s and an imidization ratio of about 51% (hereinafter referred to as “imidized polymer (A-2)”). ) About 3,000 g of a solution was obtained.

Polyamic acid synthesis example 1
196 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 212 g (1 of 2,2′-dimethyl-4,4′-diaminobiphenyl as diamine compound) 0.0 mol) was dissolved in N-methyl-2-pyrrolidone (370 g) and γ-butyrolactone (3,300 g) and reacted at 40 ° C. for 3 hours, and a polyamic acid having a solution viscosity of 160 mPa · s at a solid content concentration of 10% by weight (this) About 3,700 g of “polyamic acid (I-1)” solution.

Polyamic acid synthesis example 2
95 g (0.50 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride, 109 g (0.50 mol) of pyromellitic dianhydride, 2.7 as diamine compound -196 g (1.0 mol) of diaminofluorene was dissolved in 230 g of N-methyl-2-pyrrolidone and 2,060 g of γ-butyrolactone, reacted at 40 ° C for 3 hours, and then 1,350 g of γ-butyrolactone was added. About 3,600 g of a polyamic acid solution having a solid content concentration of 10% by weight and a solution viscosity of 125 mPa · s (referred to as “polyamic acid (I-2)”) was obtained.

Example 1
The polyimide (A-1) obtained in Polyimide Synthesis Example 1 and the polyamic acid (I-1) obtained in Polyamic Acid Synthesis Example 1 are polyimide: polyamic acid = 20: 80 (weight ratio). Dissolve in γ-butyrolactone / N-methyl-2-pyrrolidone / butyl cellosolve mixed solvent (weight ratio 71/17/12), add 10 parts by weight of specific compound A-1 to 100 parts by weight of polymer, solid content concentration A 3.5 wt% solution and a 6.0 wt% solution were made. 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 subjected to ultrasonic cleaning for 1 minute in ultrapure water and dried in a 100 ° C. clean oven for 10 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.) was filled between the substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an acrylic photo-curing adhesive to produce 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.
Moreover, printability evaluation was performed according to the method described above using a solution having a solid content concentration of 6.0% by weight.

Examples 2-4
The same procedure as in Example 1 was performed except that the compounds described in Table 1 were used as the polyimide, polyamic acid, and specific compound.

Example 5
The polyimide (A-2) obtained in Polyimide Synthesis Example 2 is dissolved in an N-methyl-2-pyrrolidone / butyl cellosolve mixed solvent (weight ratio 50/50), and the specific compound A-1 is added to 100 parts by weight of the polymer. On the other hand, 10 parts by weight was added to prepare a solution having a solid 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. 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 6
The same procedure as in Example 5 was performed except that the compounds shown in Table 1 were used as the specific compound.

Comparative Examples 1-2
The same procedures as in Example 1 were performed except that the materials described in Table 1 were used as polyimide and polyamic acid, and no specific compound was added.

Comparative Example 3
The same procedure as in Example 5 was performed except that the specific compound was not added.

Comparative Examples 4-5
The polyimide and polyamic acid used were those shown in Table 1, except that N, N′-diphenyl-N, N′-di (m-tolyl) benzidine (Compound Z) was used as the specific compound. The same procedure was performed.

Comparative Example 6
The same procedure as in Example 5 was performed except that N, N′-diphenyl-N, N′-di (m-tolyl) benzidine (Compound Z) was used as the specific compound.
The results of the above examples and comparative examples are all shown in Table 1. In Table 1, “-” indicates that the component corresponding to the column was not used. Further, “> 99%” in the voltage holding ratio column indicates that the measured value exceeds 99%.

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

Claims (6)

The liquid crystal aligning agent characterized by including the compound represented by following formula (1).

(Wherein R _{1 to} R ₄ are each independently a hydrogen atom or an aliphatic group, R _{5 to} R ₉ are a hydrogen atom, an alkyl group, an alkoxy group or an aromatic group, and A is a hydrogen atom or an aliphatic group) A group.) R ₁ to R ₄ in the formula (1) are each independently, a liquid crystal aligning agent of claim 1 is an aliphatic group containing a hydrogen atom or an epoxy group. The R _{1 to} R ₄ in the formula (1) are each independently an aliphatic group containing an epoxy group, and A is an aliphatic group containing a hydrogen atom or an epoxy group. Liquid crystal aligning agent. The compound according to any one of claims 1 to 3, and a polyamic acid composed of a repeating unit represented by the following formula (I-1) and a polyimide composed of a repeating unit represented by (I-2). A liquid crystal aligning agent comprising at least one polymer.

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

(Where P ² is a tetravalent organic group and Q ² is a divalent organic group.)   At least one part of tetracarboxylic dianhydride used for the synthesis of the polyamic acid composed of the repeating unit represented by the formula (I-1) and the polyimide composed of the repeating unit represented by the formula (I-2) is 2, The liquid crystal aligning agent according to claim 4, which is 3,5-tricarboxycyclopentylacetic acid dianhydride.   A liquid crystal display element comprising a liquid crystal alignment film obtained using the liquid crystal aligning agent according to claim 1.

Images