JP5057062B2 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element. More specifically, a liquid crystal aligning agent that provides a liquid crystal alignment film that has good electrical characteristics and liquid crystal alignment properties, and that hardly causes scratches (hereinafter also referred to as “rubbing scratches”) due to rubbing treatment on the surface of the liquid crystal alignment film. The present invention relates to a liquid crystal alignment film and a liquid crystal display element including the same.

Conventionally, a cell of a sandwich structure is formed by forming a nematic liquid crystal layer having positive dielectric anisotropy between two substrates having a liquid crystal alignment film formed on the surface via a transparent conductive film, There is known a TN liquid crystal display element having a TN (Twisted Nematic) type liquid crystal cell in which the major axis of liquid crystal molecules is continuously twisted by 90 degrees from one substrate toward the other substrate. The alignment of the liquid crystal in the liquid crystal display element such as the TN liquid crystal display element is usually realized by a liquid crystal alignment film provided with the alignment ability of liquid crystal molecules by rubbing treatment. Here, as materials for the liquid crystal alignment film constituting the liquid crystal display element, resins such as polyimide, polyamide, and polyester are conventionally known. In particular, polyimide is used in many liquid crystal display elements because of its excellent heat resistance, affinity with liquid crystals, mechanical strength, and the like. An example of improving the rubbing treatment resistance in a liquid crystal alignment film material using a polyimide resin is disclosed in Patent Document 1.
Patent Document 1 discloses a method of adding an epoxy compound containing a nitrogen atom to polyimide and polyamic acid resin. This inventor examined in order to express the further rubbing process tolerance in liquid crystal aligning film material.
JP 10-333153 A

  As a result of studying the structure of a compound containing two nitrogen atoms in the molecule disclosed in Patent Document 1, the present inventor has added a specific nitrogen-containing compound to polyimide and polyamic acid resin. Thus, the present inventors have found that the resistance to rubbing treatment can be further improved and completed the present invention. The reason why the rubbing treatment resistance is improved is presumed to be that the film density and film hardness of the alignment film are improved by adding a specific nitrogen-containing compound.

That is, the present invention is as follows.
A liquid crystal aligning agent comprising a compound represented by the following formula (I): (hereinafter sometimes referred to as a specific compound).

（式中、ＡおよびＢは、互に独立に、２価の有機基であり、Ｒ _４ 〜Ｒ _７ は水素原子または１価の有機基である。）
上記式（Ｉ）において、ｍが２でありそしてＲ_３が水素原子である特定化合物を含有する液晶配向剤が好ましい。
また、特定化合物として、下記式（ＩＩ）で表わされる特定化合物を含有する液晶配向剤がさらに好ましい。
(In the formula, R ₁ is a monovalent organic group having a 5- to 8-membered nitrogen atom represented by the following formula (R1) , and R ₂ is represented by the following formula (R2). And a monovalent organic group having a heterocyclic ring having a 5- to 8-membered nitrogen atom , m is an integer of 1 to 3, and R ₃ is a hydrogen atom or a monovalent organic group.)

(In the formula, A and B are each independently a divalent organic group, and R _{4 to} R ₇ are a hydrogen atom or a monovalent organic group.)
In the above formula (I), a liquid crystal aligning agent containing a specific compound in which m is 2 and R ₃ is a hydrogen atom is preferable.
Moreover, as a specific compound, the liquid crystal aligning agent containing the specific compound represented by following formula (II) is further more preferable.

(In the formula, A and B are each independently a divalent organic group, and R _{4 to} R ₇ are a hydrogen atom or a monovalent organic group.)
In formula (II), A and B, in each other _{independently, -CH 2 -, - CH 2} CH 2 -, or _-CH 2 _CH 2 CH ₂ - liquid crystal aligning agent containing a specific compound which is either Is more preferable.

In Formula (II), any one of R ₄ and R ₅ and any one of R ₆ and R _{7 is} a monovalent organic group containing an amino group, and A and B are both —CH ₂ CH _The liquid crystal aligning agent containing the specific compound which is 2- is also preferable.
In addition, in the formula (II), at least one of R _{4 to} R _{7 is} a monovalent organic group containing an epoxy group, and A and B each contain a specific compound that is —CH ₂ CH ₂ —. Agents are also preferred.

Furthermore, the specific compound of the above formula (II), wherein any one of R ₄ and R ₅ and any one of R ₆ and R ₇ is a monovalent organic group containing an amino group, tetracarboxylic dianhydride, The liquid crystal aligning agent characterized by containing the polyamic acid polymer obtained by reaction of this is also provided by this invention.
Therefore, according to the present invention, at least one of the specific compound and the polyamic acid polymer, a polyamic acid composed of a repeating unit represented by the following formula (I-1), and the following formula (I-2) are represented. A liquid crystal aligning agent comprising at least one polymer selected from polyimides composed of repeating units is preferably provided.

(Where 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)
P ¹ in the above formula (I-1) and P ² in the above formula (I-2) are preferably derived from 2,3,5-tricarboxycyclopentylacetic acid dianhydride.

  According to the present invention, it is possible to obtain a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element that have good electrical characteristics and liquid crystal alignment properties, and that hardly cause rubbing scratches on the surface of the liquid crystal alignment film.

  Hereinafter, the present invention will be specifically described.

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

[Specific compounds]
In the above formula (I), R ₁ and R ₂ are monovalent organic groups having a heterocyclic ring having a 5- to 8-membered nitrogen atom. These heterocycles may form a condensed ring obtained by condensing aromatics. In particular,

Etc. In addition, a monovalent organic group may be bonded to each aromatic ring having the above structure. In this

Is preferred.
In the above formula (I), m is an integer of 1 to 3, and preferably m is 2. R ₃ is a hydrogen atom or a monovalent organic group. As the monovalent organic group, an alkyl group and an alkoxyl group are preferable, and an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms are more preferable. 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. R ₃ is most preferably a hydrogen atom.

In the above formula (II), R _{4 to} R ₇ are hydrogen or a monovalent organic group. The monovalent organic group is preferably an alkyl group, an alkoxyl group, a phenyl group or a phenoxy group, more preferably an alkyl group having 1 to 6 carbon atoms or 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, the phenyl group and the phenoxy group may have a substituent on the aromatic ring. The substituent is preferably a monovalent organic group containing an amino group and an epoxy group. Specific examples of R _{4 to} R ₇ include the following structures.

In the above specific compound, when either one of R ₄ and R ₅ and one of R ₈ and R _{9 is} a monovalent organic group containing an amino group, it is reacted with an acid anhydride to obtain a polyamic acid. be able to. In synthesizing this polyamic acid, the acid anhydride is not particularly limited, but preferred are 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3, 4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic 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-dione, 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, pyromellitic dianhydride, etc. are used. These acid anhydrides can be used alone or in combination of two or more.

  In addition to the specific compound having a diamine structure, other diamine compounds may be used in combination as the diamine compound. Preferred examples of the other diamine compounds include 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-phenylenediisopropylidene) bisaniline, 4,4'-(m-phenylene Isopropylidene) bisaniline, 1,4-cyclohexanediamine, 4,4′-methylenebis (cyclohexylamine), 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, 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. These diamines can be used alone or in combination of two or more.

[Polyamic acid and polyimide]
<Tetracarboxylic dianhydride>
Examples of the tetracarboxylic dianhydride used for the synthesis of the polyamic acid composed of the repeating unit represented by the formula (I-1) include alicyclic tetracarboxylic dianhydrides, aliphatic tetracarboxylic dianhydrides, and aromatics. Group 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 (III) and (IV),

(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 (III), the following formulas (5) to (7) Alicyclic tetracarboxylic dianhydrides such as compounds represented by the following formula (8) among compounds represented by the above formula (IV) and alicyclic tetracarboxylic dianhydrides such as compounds 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-tri Carboxycyclopentyl 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] Fran-1,3-di 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).

In addition, other preferable tetracarboxylic dianhydrides other than alicyclic tetracarboxylic dianhydrides include, 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.
Among these tetracarboxylic dianhydrides, it is preferable that the alicyclic tetracarboxylic dianhydride accounts for 50 mol% or more based on the total tetracarboxylic dianhydrides.

<Diamine>
Examples of the diamine used for the synthesis of the polyamic acid composed of the repeating unit represented by the formula (I-1) include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, and 4,4′-. Diaminodiphenylethane, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenylsulfone, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diamino Biphenyl, 4,4'-diaminobenzanilide, 4,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 3,3'-ditrifluoro Methyl-4,4′-diaminobiphenyl, 5-amino-1- (4′-aminophenyl) -1,3,3-trime Luindan, 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-amino) Phenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -10-hydroa Anthracene, 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, 4,4′-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; represented by the following formula (V) Such as diamino organo siloxanes are. 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.

The polyimide comprising the repeating unit represented by the formula (I-2) can be obtained by dehydrating and ring-closing the polyamic acid comprising the repeating unit represented by the formula (I-1).
In the case where the liquid crystal aligning agent of the present invention has pretilt angle expression, a part or all of Q ¹ and Q ^{2 in} the above formulas (I-1) and (I-2) are represented by the following formula (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 also 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- Preferable 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 preferably such that the total amount (β) of tetracarboxylic dianhydride and diamine compound is 0.1 to 30% by weight with respect to 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, diisobutyl ketone, isoamylpropionate, isoamylisobutyrate , And the like di-iso-pentyl ether.

  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 polymer precursor (polyamic acid)

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 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 alignment agent of the present invention preferably has a viscosity of 20 to 800 mPa · s, and a viscosity of 30 to 500 mPa · s when a 10% by weight solution is obtained. It is more preferable that
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 predetermined solid content concentration using a predetermined solvent.

[Liquid crystal aligning agent]
The liquid crystal aligning agent of the present invention comprises at least one of the specific compound and the specific polyamic acid polymer, preferably the polymer, and other components optionally added, usually dissolved in an organic solvent. Is done.
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, diisobutyl ketone (DIBK), isoamyl propionate, isoamyl isobutyrate, diisopentyl ether 3-butoxy- N, N-dimethylpropanamide, 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 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. 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, N, N-diglycidyl - benzylamine, N, N-diglycidyl - aminomethyl cyclohexane, 3- (N-Ariru N Gurishijiru) aminopropyltrimethoxysilane, 3- (N, N-diglycidyl) aminopropyltrimethoxysilane Examples include silane. Among these, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether Glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N, N ′, N′-tetraglycidyl-m Xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane, N N- diglycidyl - benzylamine, N, N- diglycidyl - such as aminomethyl cyclohexane may be mentioned as preferred. The blending ratio of these functional silane-containing compounds and epoxy group-containing compounds is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight 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. To 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. 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. 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 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.

[Rubbing resistance of liquid crystal alignment film]
Using a rubbing machine with a liquid crystal alignment film formed on a quartz substrate and a roll wrapped with a rayon cloth, the length of pushing the hair foot is 0.8 mm, the roll rotation speed is 400 rpm, the stage moving speed is 3 cm / second, the number of rubbing times The rubbing process is performed under two conditions, the formed liquid crystal alignment film is washed with isopropyl alcohol, and the alignment film is visually checked to see if there are rubbing scratches from the substrate, and peeling and / or rubbing. A mark in which no scratch was generated was marked with ◯, and a mark with scratch was marked with x.

[Orientation of liquid crystal]
The presence / absence of an abnormal domain when the voltage was turned on / off (applied / released) to the liquid crystal display element was observed with a polarizing microscope, and the case where there was no abnormal domain was determined as “good”.

[Voltage holding ratio of liquid crystal display element]
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 16.7 milliseconds, and then the voltage holding ratio after 16.7 milliseconds from the application release was measured. The measuring apparatus used was VHR-1 manufactured by Toyo Corporation.

<Synthesis of specific compounds>
Synthesis example 1 (amination reaction)
The following reactions are described in literature J. Org. Chem. 65, 1158 (2000).

10,11-dihydro-5H-dibenz [b, f] azepine 4.3 g (22 mmol), 4,4-dibromobiphenyl 3.12 g (10 mmol), tris (dibenzylideneacetone) dipalladium 91.6 mg (0.1 mmol) ), 2- (di-t-butylphosphino) biphenyl (119 mg, 0.4 mmol) and sodium-t-butoxide (2.98 g, 31 mmol) were added to a three-necked flask equipped with a Dimroth condenser.
After degassing and drying using a vacuum pump, the system was put into a nitrogen atmosphere. 20 ml of dehydrated toluene was added with a syringe.
The reaction was completed by heating and stirring at 80 ° C. for 15 hours.
The reaction solution was cooled to room temperature, and separated and washed twice with 1N HCl aqueous solution and once with saturated brine. The solvent was distilled off, and silica gel column purification was performed to obtain 3.24 g of Compound 1.

  Synthesis example 2 (bromination)

  3 g (5.55 mmol) of Compound 1 and 20 ml of acetic acid were placed in a three-necked flask and mixed. While cooling the reaction solution in an ice bath, 10 ml of acetic acid solution of 4.27 g (26.7 mmol) of bromine was slowly added dropwise. It stirred for 6 hours after dripping. The reaction solution was poured into 500 ml of water, and the precipitate was filtered. The resulting solid was mixed with 500 ml of water and filtered. The filtered solid was dried to obtain 3.33 g of Compound 2.

  Synthesis example 3

  The following reaction was performed in a nitrogen atmosphere.

  3 g (3.5 mmol) of compound 2, 2.1 g (15.4 mmol) of 3-aminophenylboronic acid, 0.534 g (0.46 mmol) of tetrakis (triphenylphosphine) palladium, and 20 ml of toluene were mixed in a three-necked flask. Stir. Two equivalents of 2M aqueous sodium carbonate solution were added to this solution. The solution was stirred at 100 ° C. for 12 hours. The reaction solution was cooled and separated and washed with saturated brine. The solvent was distilled off and silica gel column purification was performed to obtain 1.9 g (2.1 mmol) of the target compound 3 (specific compound A-1).

  Synthesis example 4

  A mixed solution of 1.5 g (1.66 mmol) of Compound 3, 2.46 g (26.6 mmol) of epichlorohydrin in 10 ml of THF and 1.5 ml of water is heated and stirred at 80 ° C. for 4 hours. After the reaction temperature was lowered to 60 ° C., 1 g of 50% NaOH aqueous solution was added dropwise. After heating and stirring for 4 hours, unreacted epichlorohydrin was distilled off under reduced pressure. The residue was separated and washed with toluene / water, and the solvent was distilled off to obtain 1.6 g of the target compound 4 (specific compound A-2).

Synthesis example 5
The following reaction was performed in a nitrogen atmosphere.

  Compound 2 3 g (3.5 mmol), p-nitrophenol 2.14 g (15.4 mmol), palladium acetate 62.9 mg (0.28 mmol), potassium phosphate 5.94 g (28 mmol), 2- (di-t-butylphosphine) Fino) biphenyl 125 mg (0.42 mmol) and toluene 20 ml were mixed in a three-necked flask equipped with a Dimroth condenser, and the reaction solution was heated and stirred at 100 ° C. for 12 hours. The reaction solution was separated and washed with saturated brine, and further purified with a silica gel column to obtain 2.7 g of the desired compound 5.

  Synthesis Example 6

  Compound 5 2.0 g (1.84 mmol), zinc 4.81 g (73.6 mmol), ammonium chloride 0.787 g (14.7 mmol), ethanol 20 ml, water 2.5 ml in a three-necked flask equipped with a Dimroth condenser Mixed. The reaction solution was heated and stirred at 100 ° C. for 5 hours. Zinc was filtered from the reaction solution, and the filtrate was added dropwise to 250 ml of water. The precipitated powder was filtered and dried to obtain 1.3 g of the target compound 6 (specific compound B-1).

  Synthesis example 7

  0.95g of the target compound 7 (specific compound B-2) was obtained by carrying out similarly to the synthesis example 4 using 1.0g (1.03 mmol) of compounds 6.

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 35/60/5), add 10 parts by weight of the specific compound A-1 to the polymer 100, solid content concentration 3 A 0.5 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. After being immersed in isopropyl alcohol for 1 minute, it was 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.) 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 the liquid crystal orientation evaluation of the obtained liquid crystal display element were performed according to the methods described above. The liquid crystal aligning agent of the present invention prepared as described above is applied onto a quartz substrate having a thickness of 1.5 mm by using a spinner, and a coating film is formed in the same manner as in the production of a liquid crystal display element, and the rubbing resistance. Evaluation was performed according to the method described above.

Examples 2-7
The same procedure as in Example 1 was performed except that the polyimide, polyamic acid, and the specific compound were those shown in Table 1.

Example 8
The polyimide (A-2) obtained in Polyimide Synthesis Example 2 is dissolved in an N-methyl-2-pyrrolidone / butyl cellosolve mixed solvent (weight ratio 90/10), and the specific compound A-1 is added to the polymer 100. 10 parts by weight were 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. Using this aligning agent, a liquid crystal display device was prepared according to the method described in Example 1.
The voltage holding ratio evaluation and the liquid crystal orientation evaluation of the obtained liquid crystal display element were performed according to the methods described above. The liquid crystal aligning agent of the present invention prepared as described above is applied onto a quartz substrate having a thickness of 1.5 mm by using a spinner, and a coating film is formed in the same manner as in the production of a liquid crystal display element, and the rubbing resistance. Evaluation was performed according to the method described above.

Examples 9-12
The specific compound was used in the same procedure as in Example 8 except that the compounds shown in Table 1 were used.

Comparative Examples 1-2
The polyimide and polyamic acid were the same as those used in Example 1 except that the materials shown in Table 1 were used and the specific compound was not added.

Comparative Example 3
The procedure was the same as in Example 8, except that the specific compound was not added.

Comparative Examples 4-6
The same procedure as in Example 1 was used except that the polyimide and polyamic acid used were those shown in Table 1, and N, N, N ′, N′-tetraglycidyl-m-xylenediamine (Compound X) was used as the specific compound. I went there. N, N, N ′, N′-tetraglycidyl-m-xylenediamine purchased from Mitsubishi Gas Chemical Co., Ltd. was used.

Claims (10)

The following formula (I):

(In the formula, R ₁ is a monovalent organic group having a 5- to 8-membered nitrogen atom represented by the following formula (R1) , and R ₂ is represented by the following formula (R2). And a monovalent organic group having a heterocyclic ring having a 5- to 8-membered nitrogen atom, m is an integer of 1 to 3, and R ₃ is a hydrogen atom or a monovalent organic group.)
The liquid crystal aligning agent characterized by containing the compound represented by these.

(In the formula, A and B are each independently a divalent organic group, and R _{4 to} R ₇ are a hydrogen atom or a monovalent organic group.) 2. The liquid crystal aligning agent according to claim 1, wherein in the formula (I), m is 2 and R ₃ is a hydrogen atom. The liquid crystal aligning agent according to claim 1 or 2, wherein the compound represented by the formula (I) is a compound represented by the following formula (II).

(In the formula, A 1 , B and R _{4 to} R ₇ each have the same meaning as in the above formula (I) .) A and B, in each independently a single _{bond, -CH 2 -, - CH 2} CH 2 - or _-CH 2 _CH 2 CH ₂ - liquid crystal aligning agent of claim 3 is either. R ₄ and one of one, and _{R 6} and _{R 7} in _{R 5} is a monovalent organic group containing an amino group, and A and B are both _-CH 2 CH ₂ - Claim 1 which is the liquid crystal aligning agent as claimed in any one of 1-4. R ₄ at least one of to R ₇ is a monovalent organic group containing an epoxy group, and A and B are both _-CH 2 CH ₂ - crystal according to any one of claims 1-4 in which Alignment agent. Under following formula (II) in expressed, liquid crystal, characterized by containing a polyamic acid polymer obtained by reaction of a compound with a tetracarboxylic acid dianhydride having a heterocyclic ring having 5-8 membered nitrogen-atoms Alignment agent.

(In the formula, A and B are each independently a divalent organic group, R _{4 to} R ₇ are a hydrogen atom or a monovalent organic group, provided that either one of R ₄ and R ₅ and Either one of R ₆ and R _{7 is} a monovalent organic group containing an amino group.) The compound according to any one of claims 1 to 6 and the polyamic acid polymer according to claim 7, and a polyamic acid comprising a repeating unit represented by the following formula (I-1) and (I-2) A liquid crystal aligning agent comprising at least one polymer selected from the group consisting of polyimides consisting of repeating units represented by formula (1).

(Where 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) The liquid crystal aligning agent of claim 8 derived from the above formula ^{(I-1) P} 1 and the formula (I-2) in the ^{P 2} are 2,3,5-tricarboxycyclopentylacetic dianhydride in. A liquid crystal display element comprising a liquid crystal alignment film obtained by using the liquid crystal aligning agent according to claim 1.