JP5071662B2 - Liquid crystal aligning agent and liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal aligning agent and a liquid crystal display element. More specifically, a liquid crystal aligning agent that provides a liquid crystal alignment film excellent in printability and heat resistance, and capable of high-quality display, display deterioration due to thermal stress is suppressed, and liquid crystal display that can be driven for a long time It relates to an element.

Currently, as a liquid crystal display element, a liquid crystal alignment film 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 so-called TN type (twisted) in which a layer of a nematic liquid crystal having a property is formed into a sandwich cell and the major axis of liquid crystal molecules is continuously twisted by 90 ° from one substrate to the other. A TN liquid crystal display element having a (Nematic) liquid crystal cell is widely known. In addition, an STN (Super Twisted Nematic) type liquid crystal display element capable of realizing a high contrast ratio as compared with a TN type liquid crystal display element, an IPS (In-Plane Switching) type liquid crystal display element with less viewing angle dependency, and an IPS type electrode structure FFS (Fringe Field Switching) type liquid crystal display element with improved brightness by changing the aperture ratio of the display element part, and VA (Vertical Alignment) type liquid crystal display element, which has less viewing angle dependency and high-speed response of the video screen An OCB (Optical Compensated Bend) type liquid crystal display element having excellent properties has been developed.
As materials for the liquid crystal alignment film in these liquid crystal display elements, resin materials such as polyamic acid, polyimide, polyamide, and polyester are known, and in particular, a liquid crystal alignment film made of polyamic acid or polyimide has heat resistance, mechanical strength, It has excellent affinity with liquid crystals and is used in many liquid crystal display elements (see, for example, Patent Documents 1 to 3).

In such a liquid crystal aligning agent, a silane coupling agent is added for the purpose of improving the film thickness uniformity of the coating film to be formed, particularly the film thickness at the center and the film thickness at the edge of the substrate. Attempts have been made (see Patent Document 4). However, although the liquid crystal aligning agent to which the silane coupling agent is added improves the film thickness uniformity of the formed coating film, bubbles tend to be generated when the liquid crystal aligning agent is applied. There is a problem that the orientation of the liquid crystal is impaired due to holes.
Liquid crystal aligning agents that can provide a liquid crystal alignment film having excellent heat resistance, are excellent in printability without generating bubbles at the time of coating, and have sufficient film thickness uniformity of the formed coating film are conventionally known. Absent.
JP-A-9-197411 JP 2003-149648 A JP 2003-107486 A JP-A 61-171762 JP-A-6-222366 JP-A-6-281937 JP-A-5-107544

The present invention has been made in view of the above circumstances, and an object thereof is to provide a liquid crystal alignment film having excellent heat resistance, and excellent printability without formation of bubbles during coating. It aims at providing the liquid crystal aligning agent with sufficient film thickness uniformity of a coating film.
Another object of the present invention is to provide a liquid crystal display element capable of high-quality display and having no deterioration in display performance even when driven for a long time .
Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the object of the present invention is firstly as follows:
Tetracarboxylic dianhydride and the following formula (A)

(In Formula (A), R ^I is an alkyl group having 1 to 10 carbon atoms, a branched alkyl group having 11 to 30 carbon atoms, or an alicyclic group having 17 to 30 carbon atoms having a steroid skeleton, and R ^II is Single bond, oxygen atom, —COO— or —OOC—.)
It is achieved by a liquid crystal aligning agent containing at least one polymer selected from the group consisting of a polyamic acid obtained by reacting with a diamine containing a compound represented by formula (I) and a polyimide obtained by dehydrating and ring-closing the polyamic acid. .
The above object of the present invention is secondly,
This is achieved by a liquid crystal display element comprising a liquid crystal alignment film formed from the above liquid crystal aligning agent .

The liquid crystal aligning agent of the present invention can form a liquid crystal aligning film in which the liquid crystal aligning ability does not deteriorate even when a long-term heat stress is applied. The liquid crystal alignment film formed from the liquid crystal aligning agent of the present invention is suitable for various liquid crystal display elements such as TN type, STN type, IPS type, FFS type, VA type, OCB type, ferroelectricity and antiferroelectricity. Can be applied to.
The liquid crystal display element of the present invention having such a liquid crystal alignment film is capable of high-quality display, and display performance does not deteriorate even when driven for a long time. Therefore, the liquid crystal display element of the present invention can be effectively applied to various devices, such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, portable information terminals, digital cameras, cellular phones, Used for display devices such as various monitors and liquid crystal televisions.

Hereinafter, the present invention will be described in detail.
The liquid crystal aligning agent of the present invention comprises a polyamic acid obtained by reacting a tetracarboxylic dianhydride and a diamine containing the compound represented by the above formula (A), and a polyimide obtained by dehydrating and ring-closing the polyamic acid. At least one polymer selected from the group consisting of:

[Tetracarboxylic dianhydride]
Examples of the tetracarboxylic dianhydride used for synthesizing the polyamic acid contained in the liquid crystal aligning agent of the present invention include butanetetracarboxylic dianhydride and 1,2,3,4-cyclobutanetetracarboxylic acid dihydrate. Anhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic 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 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6-tricarboxynorbornane-2-acetic acid 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)- -Methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, bicyclo [2.2.2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 3-oxa Bicyclo [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-dioxa Tricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone, the following formulas (TI) and (T-II)

(Wherein R ¹ and R ³ are each a divalent organic group having an aromatic ring, R ² and R ⁴ are each a hydrogen atom or an alkyl group, and a plurality of R ² and R ^{4 are present.} May be the same or different.)
An aliphatic or alicyclic tetracarboxylic dianhydride such as a compound represented by each of the following:
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), the following formulas (T-1) to (T-4)

An aromatic tetracarboxylic dianhydride such as a compound represented by each of the above can be exemplified. These may be used alone or in combination of two or more.
The tetracarboxylic dianhydride used for synthesizing the polyamic acid contained in the liquid crystal aligning agent of the present invention is butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic. Acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic 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, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1, 3-Geo 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-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid Acid 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 acid Water, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfonetetracarboxylic dianhydride, 2,2 ′, 3,3′- Among the compounds represented by biphenyltetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, and the above formula (TI), the following formulas (T-5) to (T-7) )

Of the compounds represented by each of the above and the compounds represented by the above formula (T-II), the following formula (T-8)

It is preferable that the liquid crystal orientation is a tetracarboxylic dianhydride containing at least one selected from the group consisting of compounds represented by the following (hereinafter referred to as “specific tetracarboxylic dianhydride (1)”). Is more preferable from the viewpoint of expressing the above.
As the specific tetracarboxylic dianhydride (1), in particular, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 1,3,3a, 4,5,9b-Hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 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 acid Anhydride, 3,5,6-tricarboxy-2-carboxymethyl norbornane -2: 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^{2, 6]} undecane It is preferably at least one selected from the group consisting of -3,5,8,10-tetraone, pyromellitic dianhydride and a compound represented by the above formula (T-5).
Examples of the tetracarboxylic dianhydride used for synthesizing the polyamic acid contained in the liquid crystal aligning agent of the present invention include the specific tetracarboxylic dianhydride (1) as described above, and all tetracarboxylic dianhydrides. It is preferable to contain 20 mol% or more, and more preferably 30 mol% or more.

[Diamine]
The diamine used for synthesizing the polyamic acid contained in the liquid crystal aligning agent of the present invention contains a compound represented by the above formula (A). As the alkyl group having 1 to 10 carbon atoms of R ¹ in the formula (A), a linear alkyl group having 1 to 10 carbon atoms is preferable, and specific examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, Examples thereof include a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. Examples of the branched alkyl group having 11 to 30 carbon atoms include a 1-methyldodecyl group, a 1-methyltetradecyl group, and a 1-methylhexadecyl group. The steroid skeleton in the alicyclic group having 17 to 30 carbon atoms having a steroid skeleton refers to a cyclopentano-perhydrophenanthrene skeleton or a skeleton in which one or more of carbon-carbon bonds included in the skeleton is a double bond. Examples of the alicyclic group having 17 to 30 carbon atoms having such a steroid skeleton include a cholestanyl group and a cholesteryl group.
Specific examples of the compound represented by the above formula (A) include, for example, N, N-bis (4-aminophenyl) -p-hexylphenylamine, N, N-bis (4-aminophenyl) -p-octyl. Phenylamine, N, N-bis (4-aminophenyl) -p- (1-methyltetradecyl) phenylamine, N, N-bis (4-aminophenyl) -p- (cholestanyloxycarbonyl) phenylamine, N, N-bis (4-aminophenyl) -p- (cholesteryloxycarbonyl) phenylamine, N, N-bis (4-aminophenyl) -p- (cholestanyloxy) phenylamine, N, N-bis ( 4-aminophenyl) -p- (cholesteryloxy) phenylamine and the like.

As the diamine for synthesizing the polyamic acid contained in the liquid crystal aligning agent of the present invention, only the compound represented by the above formula (A) may be used alone, or the compound represented by the above formula (A). And other diamines may be used in combination.
Examples of other diamines that can be used in the present invention include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, and 4,4′-diaminodiphenyl sulfide. 4,4′-diaminodiphenyl sulfone, 3,3′-dimethyl-4,4′-diaminobiphenyl, 4,4′-diaminobenzanilide, 4,4′-diaminodiphenyl ether, 1,5-diaminonaphthalene, 2, 2,2′-dimethyl-4,4′-diaminobiphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl, 2,2′-ditrifluoromethyl-4,4′-diaminobiphenyl, 3,3 ′ -Ditrifluoromethyl-4,4'-diaminobiphenyl, 5-amino-1- (4'-aminophenyl) -1,3,3-to Methylindane, 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) -10-hydride 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 or cycloaliphatic diamines such as 1,4′-methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane;
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, the following formula (DI)

(In the formula (DI), R ⁵ is a monovalent organic group having a ring structure containing a nitrogen atom selected from the group consisting of pyridine, pyrimidine, triazine, piperidine and piperazine, and X ¹ is divalent. Organic group.)
A compound represented by formula (D-II):

(In formula (D-II), X ² is a divalent organic group having a ring structure containing a nitrogen atom selected from the group consisting of pyridine, pyrimidine, triazine, piperidine and piperazine, and R ⁶ is (It is a divalent organic group, and a plurality of X ² may be the same or different.)
A diamine having two primary amino groups and a nitrogen atom other than the primary amino group in a molecule such as a compound represented by:
The following formula (D-III)

(In Formula (D-III), R ⁷ is a divalent organic group selected from the group consisting of —O—, —COO—, —OCO—, —NHCO—, —CONH—, and —CO—. , R ⁸ is a monovalent organic group having a steroid skeleton, a trifluoromethylphenyl group, a trifluoromethoxyphenyl group, and a skeleton selected from the group consisting of a fluorophenyl group, or an alkyl group having 6 to 30 carbon atoms. is there.)
A mono-substituted phenylenediamine represented by:
The following formula (D-IV)

(In the formula (D-IV), each R ⁹ represents a hydrocarbon group having 1 to 12 carbon atoms, and a plurality of R ⁹ may be the same or different from each other, , An integer of 1 to 3, and q is an integer of 1 to 20.)
Diaminoorganosiloxane represented by:
The following formulas (D-1) to (D-5)

(Y in the formula (D-4) is an integer of 2 to 12, and z in the formula (D-5) is an integer of 1 to 5.)
The compounds represented by each of the above can be mentioned.
These diamines can be used alone or in combination of two or more.
Other diamines that can be used in the present invention include p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,2 among the above. '-Dimethyl-4,4'-diaminobiphenyl, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 2,7-diaminofluorene, 4,4'-diaminodiphenyl ether, 2,2-bis [ 4- (4-aminophenoxy) phenyl] propane, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-Aminophenyl) hexafluoropropane, 4,4 ′-(p-phenylenediisopropylidene) bisaniline, 4 4 ′-(m-phenylenediisopropylidene) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 1,4-cyclohexanediamine, 4,4 '-Methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane, compounds represented by the above formulas (D-1) to (D-5), 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, represented by the above formula (DI) Formula Of the compounds (D-6)

  Of the compounds represented by formula (D-II), the following formula (D-7)

Of the compounds represented by formula (D-III), dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy- 2,4-diaminobenzene, dodecanoxy-2,5-diaminobenzene, pentadecanoxy-2,5-diaminobenzene, hexadecanoxy-2,5-diaminobenzene, octadecanoxy-2,5-diaminobenzene, the following formula (D-8) ~ (D-16)

And at least one selected from the group consisting of 1,3-bis (3-aminopropyl) -tetramethyldisiloxane among the compounds represented by formula (D-IV) And “specific diamine (1)”).
The diamine used for synthesizing the polyamic acid contained in the liquid crystal aligning agent of the present invention preferably contains 0.1 mol% or more of the compound represented by the above formula (A) with respect to the total diamine. It is more preferable to contain 0.1-30 mol%, and it is especially preferable to contain 0.1-20 mol%. The diamine used in the present invention preferably contains the specific diamine (1) as described above in addition to the compound represented by the above formula (A). In this case, the proportion of the specific diamine (1) used is preferably 0.1 to 30 mol%, more preferably 0.1 to 20 mol%, particularly 0.1 It is preferable that it is 10 mol%.

[Synthesis of polyamic acid]
The polyamic acid contained in the liquid crystal aligning agent of the present invention is obtained by reacting a tetracarboxylic dianhydride with a diamine containing a compound represented by the above formula (A).
The ratio of the tetracarboxylic dianhydride and the diamine used in the polyamic acid synthesis reaction is 0.2 to 2 for the tetracarboxylic dianhydride acid anhydride group to 1 equivalent of the amino group of the diamine. The ratio which becomes an equivalent is preferable, More preferably, it is the ratio which becomes 0.3-1.2 equivalent.
The polyamic acid synthesis reaction is preferably performed in an organic solvent, preferably at a temperature of −20 ° C. to 150 ° C., more preferably 0 to 100 ° C., and preferably 0.1 to 24 hours, more preferably 0.00. 1 to 12 hours. Here, the organic solvent is not particularly limited as long as it can dissolve the polyamic acid to be produced. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, Examples include aprotic polar solvents such as γ-butyrolactone, tetramethylurea and hexamethylphosphortriamide; and phenolic solvents such as m-cresol, xylenol, phenol and halogenated phenol. The amount (a) of the organic solvent used is such that the total amount (b) of the tetracarboxylic dianhydride and the diamine compound is 0.1 to 30% by weight with respect to the total amount (a + b) of the reaction solution. It is preferable.

For the organic solvent, alcohol, ketone, ester, ether, halogenated hydrocarbon, hydrocarbon and the like, which are poor solvents for polyamic acid, can be used in combination as long as the polyamic acid to be produced does not precipitate. Specific examples of the poor solvent include, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, 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, diethyl malonate, diethyl ether, ethylene glycol methyl ether, ethylene Glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n- Chill 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 ether and the like.
When the organic solvent and the poor solvent are used in combination, the amount of the poor solvent used can be appropriately set within the range in which the polyamic acid to be produced does not precipitate, but is preferably 50% by weight or less based on the total amount of the solvent. 40% by weight or less, more preferably 30% by weight or less.

  As described above, a reaction solution obtained by dissolving polyamic acid is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal aligning agent, may be used for the preparation of the liquid crystal aligning agent after isolating the polyamic acid contained in the reaction solution, or the isolated polyamic acid was purified. You may use for preparation of a liquid crystal aligning agent. Polyamic acid can be isolated by pouring the reaction solution into a large amount of poor solvent to obtain a precipitate, and drying the precipitate under reduced pressure, or by distilling the reaction solution under reduced pressure using an evaporator. it can. Further, the polyamic acid can be purified by a method of dissolving the polyamic acid again in an organic solvent and then precipitating with a poor solvent, or a method of performing the step of distilling under reduced pressure with an evaporator once or several times.

<Polyimide>
The polyimide that can be contained in the liquid crystal aligning agent of the present invention can be obtained by dehydrating and ring-closing the polyamic acid as described above to imidize.
Examples of the tetracarboxylic dianhydride used for the synthesis of the polyimide include the same compounds as the tetracarboxylic dianhydride used for the synthesis of the polyamic acid described above.
The tetracarboxylic dianhydride used for the synthesis of the polyimide contained in the liquid crystal aligning agent of the present invention is at least one selected from alicyclic tetracarboxylic dianhydrides (hereinafter referred to as “specific tetracarboxylic dianhydride ( It is preferable that it is tetracarboxylic dianhydride containing 2) ". Specific tetracarboxylic dianhydrides (2) include 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, 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-carboxyno Bornane -2: 3,5: selected from 6-dianhydride and 4,9-dioxatricyclo [5.3.1.0 ^{2, 6]} undecane -3,5,8,10- tetraone group consisting At least one of the above is preferred.
The tetracarboxylic dianhydride used for the synthesis of the polyimide contained in the liquid crystal aligning agent of the present invention is a specific tetracarboxylic dianhydride (2) as described above with respect to all tetracarboxylic dianhydrides. It is preferable to contain 1 mol% or more, more preferably 1.0 mol% or more, and particularly preferably 10 mol% or more.

Examples of the diamine used for synthesizing the polyimide contained in the liquid crystal aligning agent of the present invention include the same diamine as the diamine compound used for the synthesis of the polyamic acid. That is, the diamine used for the synthesis | combination of the polyimide contained in the liquid crystal aligning agent of this invention contains the compound represented by the said Formula (A).
The diamine used for synthesizing the polyimide contained in the liquid crystal aligning agent of the present invention is at least selected from the compound represented by the above formula (D-III) in addition to the compound represented by the above formula (A). One type (hereinafter referred to as “specific diamine (2)”) is preferably included. As the specific diamine (2), dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy-2,4-diaminobenzene, dodecanoxy-2, 5-diaminobenzene, pentadecanoxy-2,5-diaminobenzene, hexadecanoxy-2,5-diaminobenzene, octadecanoxy-2,5-diaminobenzene and compounds represented by the above formulas (D-8) to (D-16) It is preferably at least one selected from the group consisting of:
The diamine used to synthesize the polyimide contained in the liquid crystal aligning agent of the present invention is a diamine other than the compound represented by the above formula (A) and the compound represented by the above formula (D-III). May be included. Examples of such other diamines include the specific diamine (1), except for those corresponding to the specific diamine (2).
The diamine used for synthesizing the polyimide contained in the liquid crystal aligning agent of the present invention preferably contains 0.1 mol% or more of the compound represented by the above formula (A) with respect to the total diamine. More preferably, it is contained in an amount of 1 to 30 mol%, and particularly preferably 0.1 to 20 mol%. Moreover, it is preferable that the diamine used for this invention contains the above specific diamine (2) other than the compound represented by the said Formula (A). In this case, the specific diamine (2) is preferably used in an amount of 0.5 to 30 mol%, more preferably 1 to 20 mol%, particularly 1.0 to 10 mol% based on the total diamine. It is preferable that it is mol%.

The polyimide contained in the liquid crystal aligning agent of the present invention may be a completely imidized product obtained by dehydrating and cyclizing all of the amic acid structure that the polyamic acid as a raw material had, and only a part of the amic acid structure is dehydrated. It may be a partially imidized product that is ring-closed and has both an amic acid structure and an imide ring structure.
The polyimide contained in the liquid crystal aligning agent of the present invention preferably has an imidation ratio of 30% or more, more preferably 80% or more, and particularly preferably 85% or more.
The said imidation rate represents the ratio which the number of the imide ring structure accounts with respect to the sum total of the number of the amic acid structures of polyimide, and the number of imide ring structures in percentage. At this time, a part of the imide ring may be an isoimide ring. The imidation rate is calculated by the following formula (i) based on the result of ¹ H-NMR measured at room temperature using tetramethylsilane as a reference substance by dissolving polyimide in a suitable deuterated solvent (for example, deuterated dimethyl sulfoxide). Can be sought.
Imidation rate (%) = (1-A ¹ / A ² × α) × 100 (i)
(In Formula (i), A ¹ is a peak area derived from protons of NH groups appearing near a chemical shift of 10 ppm, A ² is a peak area derived from other protons, and α is a polyimide precursor (polyamic acid). The number ratio of other protons to one proton of NH group in

The dehydration ring closure of the polyamic acid is preferably performed by (i) a method of heating the polyamic acid, or (ii) dissolving the polyamic acid in an organic solvent, and adding a dehydrating agent and a dehydration ring closure catalyst to this solution as necessary. This is done by heating.
The reaction temperature in the method (i) of heating the polyamic acid is preferably 50 to 200 ° C, more preferably 60 to 170 ° C. The reaction time is preferably 1.0 to 24 hours, more preferably 1.0 to 12 hours. 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 resulting polyimide 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. Although the usage-amount of a dehydrating agent is based on the desired imidation rate, it is preferable to set it as 0.01-20 mol with respect to 1 mol of the amic acid structure of a polyamic acid. 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-closing catalyst used is preferably 0.01 to 10 mol with respect to 1 mol 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. Examples of the organic solvent used in the dehydration ring-closing reaction include the organic solvents exemplified as those used for the synthesis of polyamic acid. The reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C, more preferably 10 to 150 ° C. The reaction time is preferably 1.0 to 24 hours, more preferably 1.0 to 12 hours.

  The polyimide obtained in the above method (i) may be used for the preparation of the liquid crystal aligning agent as it is, or may be used for the preparation of the liquid crystal aligning agent after purifying the obtained polyimide. On the other hand, in the above method (ii), a reaction solution containing polyimide is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal aligning agent, or may be used for the preparation of the liquid crystal aligning agent after removing the dehydrating agent and the dehydrating ring-closing catalyst from the reaction solution. It may be used for the preparation of a liquid crystal aligning agent or may be used for the preparation of a liquid crystal aligning agent after purifying the isolated polyimide. In order to remove the dehydrating agent and the dehydrating ring-closing catalyst from the reaction solution, for example, a method such as solvent replacement can be applied. The isolation and purification of the polyimide can be performed by performing the same operation as described above as the isolation and purification method of the polyamic acid.

-End-modified polymer-
The polyamic acid or polyimide contained in the liquid crystal aligning agent of the present invention may be of a terminal modified type whose molecular weight is adjusted. By using the terminal-modified polymer, the coating properties of the liquid crystal aligning agent can be further improved without impairing the effects of the present invention. Such a terminal-modified polymer can be obtained by adding a molecular weight modifier to a polymerization reaction system when synthesizing a polyamic acid. Examples of molecular weight regulators include acid monoanhydrides, monoamine compounds, monoisocyanate compounds, and the like.
Examples of the acid monoanhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic anhydride, n -Hexadecyl succinic anhydride etc. can be mentioned. Examples of the monoamine compound include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, Examples include n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, and n-eicosylamine. it can. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.
The use ratio of the molecular weight modifier is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, with respect to 100 parts by weight of the total of tetracarboxylic dianhydride and diamine used when synthesizing the polyamic acid. .
-Solution viscosity-
The polyamic acid or polyimide obtained as described above preferably has a solution viscosity of 20 to 800 mPa · s, and a solution viscosity of 30 to 500 mPa · s when a 10% by weight solution is obtained. It is more preferable to have it.
The solution viscosity (mPa · s) of the above polymer is E for a polymer solution having a concentration of 10% by weight prepared using a good solvent for the polymer (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). It is a value measured at 25 ° C. using a mold rotational viscometer.

<Other additives>
The liquid crystal alignment film of the present invention contains, as an essential component, at least one selected from the group consisting of the polyamic acid as described above and a polyimide obtained by imidizing the polyamic acid, but contains other components as necessary. May be. Examples of such other components include other polymers, compounds having at least one epoxy group in the molecule (hereinafter referred to as “epoxy compound”), and functional silane compounds.
These other polymers can be used to improve solution and electrical properties. Such other polymer includes a polyamic acid obtained by reacting a tetracarboxylic dianhydride and a diamine containing the compound represented by the above formula (A), and a polymer other than a polyimide obtained by dehydrating and ring-closing the polyamic acid. A polyamic acid obtained by reacting, for example, tetracarboxylic dianhydride with a diamine not containing the compound represented by the above formula (A) (hereinafter referred to as “other polyamic acid”), the polyamic acid. Polyimide obtained by dehydrating and cyclizing acid (hereinafter referred to as “other polyimide”), polyamic acid ester, polyester, polyamide, polysiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, poly ( And (meth) acrylate. Of these, other polymic acids or other polyimides are preferred, and other polyamic acids are more preferred.
As other polymer use ratios, the total amount of the polymer (the polyamic acid obtained by reacting the tetracarboxylic dianhydride with the diamine containing the compound represented by the formula (A) and the polyamic acid) Is the total of polyimide and other polymers obtained by dehydrating and ring-closing, and the same shall apply hereinafter)), preferably 50% by weight or less, more preferably 0.1 to 40% by weight, and further 0.1 It is preferably ˜30% by weight.

Examples of the epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 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′-diame Diphenylmethane, N, N-diglycidyl - benzylamine, N, N-diglycidyl - such as aminomethyl cyclohexane may be mentioned as preferred. The blending ratio of these 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 total amount of the polymer.
Examples of the functional silane compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl)- 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyl Trimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4 7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N- Benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis ( Examples thereof include oxyethylene) -3-aminopropyltrimethoxysilane and N-bis (oxyethylene) -3-aminopropyltriethoxysilane.
The blending ratio of these functional silane-containing compounds is preferably 40 parts by weight or less with respect to 100 parts by weight of the total amount of the polymer.

In the liquid crystal aligning agent of the present invention, at least one polymer selected from the group consisting of the above polyamic acid and polyimide, and other additives optionally blended as necessary, are preferably in an organic solvent. Dissolved and contained.
Examples of the organic solvent that can be used in the liquid crystal aligning agent of the present invention include N-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 Examples include 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, isoamyl propionate, isoamyl isobutyrate, and diisopentyl ether. These can be used alone or in admixture of two or more.

The solid content concentration in the liquid crystal aligning agent of the present invention (the ratio of the total weight of components other than the solvent of the liquid crystal aligning agent to the total weight of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, and the like. The range is preferably 1 to 10% by weight. That is, the liquid crystal aligning agent of the present invention is applied to the substrate surface as described later, and preferably, when heated, a coating film that becomes a liquid crystal aligning film is formed, but the solid content concentration is less than 1% by weight. In this case, the film thickness of the coating film becomes too small to obtain a good liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10% by weight, the film thickness of the coating film becomes excessive. Thus, a good liquid crystal alignment film cannot be obtained, and the viscosity of the liquid crystal aligning agent increases, resulting in poor coating properties.
The particularly preferable range of the solid content concentration 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 solid content concentration is particularly preferably in the range of 1.5 to 4.5% by weight. 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 inkjet 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 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.

<Liquid crystal display element>
The liquid crystal display element of the present invention comprises a liquid crystal alignment film formed from the liquid crystal aligning agent of the present invention as described above.
The liquid crystal display element of the present invention can be produced, for example, by the following method.
(1) The liquid crystal aligning agent of the present invention is applied to one side of a substrate provided with a patterned transparent conductive film by an appropriate application method such as a roll coater method, a spin coating method, an offset printing method, or an ink jet printing method. Then, the coated surface is formed by heating the coated surface. Here, as the substrate, for example, a glass such as float glass or soda glass; a transparent substrate made of a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, or poly (alicyclic olefin) 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. In order to obtain a patterned transparent conductive film which can be used, for example, a method of forming a pattern by photo-etching after forming a transparent conductive film without a pattern, a mask having a desired pattern when forming the transparent conductive film The method using can be 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 compound or functional titanium is formed on the surface of the substrate surface on which the coating film is to be formed. You may give the pretreatment which apply | coats a compound etc. previously.

As for the heating after the application of the liquid crystal aligning agent, a preliminary heating (pre-baking) step and a baking (post-baking) step are preferably performed sequentially. The heating temperature of the pre-bake is preferably 30 to 300 ° C, more preferably 40 to 200 ° C, and particularly preferably 50 to 150 ° C. The prebaking heating time is preferably 0.1 to 60 minutes, more preferably 0.1 to 30 minutes, and further preferably 0.1 to 20 minutes. The post-baking step is performed for the purpose of completely removing the solvent contained in the liquid crystal aligning agent of the present invention. The heating temperature of this post-bake is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. The post-baking heating time is preferably 1.0 to 120 minutes, more preferably 1.0 to 100 minutes, and further preferably 1.0 to 80 minutes.
Although the liquid crystal aligning agent of this invention forms the coating film used as an orientation film by removing an organic solvent after application | coating, the polymer contained in the liquid crystal aligning agent of this invention is a polyamic acid or an imide ring structure, and an amic acid structure. In the case of a polyimide having both, the dehydration ring-closing reaction is advanced by further heating after the coating film is formed, and a more imidized coating film may be obtained.
The film thickness of the coating film formed here is preferably 0.001-1 μm, more preferably 0.005-0.5 μm.

(2) Next, the rubbing process which rubs the coating-film surface formed as mentioned above in a fixed direction with the roll which wound the cloth which consists of fibers, such as nylon, rayon, cotton, for example is performed. Thereby, the orientation ability of a liquid crystal molecule is provided to a coating film, and it becomes a liquid crystal aligning film.
Further, for example, Patent Document 5 (JP-A-6-222366) and Patent Document 6 (JP-A-6-281937) show liquid crystal alignment films formed by the liquid crystal aligning agent of the present invention. A process for changing the pretilt angle of a part of the liquid crystal alignment film by irradiating a part of the liquid crystal alignment film with ultraviolet rays, as disclosed in Japanese Patent Application Laid-Open No. 5-107544 After a resist film is formed on a part of the liquid crystal alignment film surface, the resist film is removed after the rubbing process in a direction different from the previous rubbing process. It is possible to improve the visual field characteristics of the liquid crystal display element obtained by having it.

(3) The pair of substrates on which the liquid crystal alignment films are formed as described above are arranged to face each other through a gap (cell gap) so that the rubbing directions of the liquid crystal alignment films of the two substrates are orthogonal or antiparallel. Then, the peripheral portions of the two substrates are bonded using a sealing agent, liquid crystal is injected and filled into the cell gap defined by the substrate surface and the sealing agent, and the injection hole is sealed to form a liquid crystal cell. And a liquid crystal display element can be obtained by bonding a polarizing plate on the outer surface of a liquid crystal cell so that the polarization direction thereof coincides with or is orthogonal to the rubbing direction of a liquid crystal alignment film formed on each substrate. 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 crystals and smectic liquid crystals. Among them, nematic liquid crystals are preferable. For example, Schiff base liquid crystals, azoxy liquid crystals, biphenyl liquid crystals, phenylcyclohexane liquid crystals, ester liquid crystals, terphenyl liquid crystals. Liquid crystals, biphenylcyclohexane liquid crystals, pyrimidine liquid crystals, dioxane liquid crystals, bicyclooctane liquid crystals, cubane liquid crystals, and the like can be used. In addition, cholesteric liquid crystals such as cholestyl chloride, cholesteryl nonate, and cholesteryl carbonate; chiral agents such as those sold under the trade names “C-15” and “CB-15” (manufactured by Merck) A ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate may be added and used.
As a polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing film or an H film itself in which a polarizing film called “H film” in which iodine is absorbed while stretching and aligning polyvinyl alcohol is sandwiched between cellulose acetate protective films The polarizing plate which consists of can be mentioned.
The liquid crystal display element of the present invention manufactured as described above has the advantage that the display performance does not deteriorate even when it is continuously driven for a long time, as compared with a conventionally known liquid crystal display element. Have.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. The polymer solution viscosity below is a value measured at 25 ° C. using an E-type viscometer.
<Synthesis Example of Compound Represented by Formula (A)>
Synthesis example 1
In a 300 mL three-necked flask under nitrogen atmosphere, 21.2 g (0.15 mol) of 4-fluoronitrobenzene, 27.4 g (0.18 mol) of cesium fluoride and 15.3 g (0.0745 mol) of 4-octylaniline Was added, and 75 mL of dimethyl sulfoxide was further added and stirred. The obtained solution was heated and stirred under nitrogen at 110 ° C. for 6 hours to carry out the reaction. After completion of the reaction, the reaction solution was mixed with 800 mL of ethanol and stirred for 1 hour. The precipitate was collected by filtration and dried (solvent removal) to obtain 11.2 g of an intermediate N, N-bis (4-nitrophenyl) -p-octylphenylamine.
Next, in a nitrogen atmosphere, 11.2 g (0.025 mol) of the intermediate synthesized above and 9.1 g of palladium / carbon were charged in a 300 mL three-necked flask, and 150 mL of tetrahydrofuran was further added, followed by stirring at 70 ° C. for 1 hour. . Thereafter, 15 mL of hydrazine monohydrate was added, and the mixture was further stirred at 80 ° C. for 3 hours under nitrogen to carry out the reaction. After completion of the reaction, the catalyst was removed by filtration, the filtrate was concentrated, and the solvent was further removed to obtain a viscous liquid. The resulting viscous liquid was purified by column chromatography (eluent: chloroform / acetone = 10/1 (volume ratio)), concentrated, and further the solvent was removed to remove N, N-bis (4-aminophenyl). 5.3 g of p-octylphenylamine was obtained.

<Synthesis examples of other polyamic acids>
Synthesis example 2
1,2,3,4-cyclobutanetetracarboxylic dianhydride 98 g (0.50 mol) and pyromellitic dianhydride 109 g (0.50 mol) as tetracarboxylic dianhydride and 4,4 as diamine compound 198 g (1.0 mol) of '-diaminodiphenylmethane was dissolved in a mixed solvent consisting of 230 g of N-methyl-2-pyrrolidone and 2,060 g of γ-butyrolactone, reacted at 40 ° C. for 3 hours, and then γ-butyrolactone 1 About 4,000 g of a solution containing 10% by weight of polyamic acid (A-1). The solution viscosity of this solution was 125 mPa · s.
Synthesis example 3
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) is dissolved in a mixed solvent consisting of 370 g of N-methyl-2-pyrrolidone and 3,300 g of γ-butyrolactone, and reacted at 40 ° C. for 3 hours, thereby containing a polyamic acid (A-2) About 4,000 g was obtained. The solution viscosity of this solution was 160 mPa · s.

<Synthesis of polyimide>
Synthesis example 4
11.2 g (0.050 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5 (Tetrahydro-2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione 15.7 g (0.050 mol), p-phenylenediamine 9.0 g (0 0.084 mol), 2.5 g (0.010 mol) of bisaminopropyltetramethyldisiloxane and 1.9 g (0.0050 mol) of N, N-bis (4-aminophenyl) -p-octylphenylamine and monoamine As an example, 0.28 g (0.0030 mol) of aniline is dissolved in 96 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours. To obtain a solution containing click acid. A small amount of the obtained polyamic acid solution was collected, and N-methyl-2-pyrrolidone was added to measure the solution viscosity as a solution having a polyamic acid concentration of 10% by weight of 60 mPa · s.
Next, 270 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 40 g of pyridine and 41 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration cyclization reaction, the solvent in the system was replaced with new γ-butyrolactone (the pyridine and acetic anhydride used in the dehydration cyclization reaction were removed from the system by this operation), whereby the imidation rate was about 95. About 270 g of a solution containing 15% by weight of polyimide (B-1) was obtained. A small amount of the obtained polyimide solution was taken, and γ-butyrolactone was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 6.0% by weight was 16 mPa · s.

<Preparation and evaluation of liquid crystal aligning agent>
Example 1
(I) Preparation of Liquid Crystal Alignment Agent A solution containing the polyamic acid (A-1) obtained in Synthesis Example 2 and a solution containing the polyimide (B-1) obtained in Synthesis Example 4 were prepared using a polyamic acid (A -1): Polyimide (B-1) = 80: 20 (weight ratio) was mixed, and γ-butyrolactone (BL), N-methyl-2-pyrrolidone (NMP) and butyl cellosolve (BC) were added thereto. In addition, 10 parts by weight of N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane as an epoxy compound was added to the total amount of 100 parts by weight of the polymer, and the mixture was sufficiently stirred. BL: NMP: BC = 71: 17: 12 (weight ratio), and a solid content concentration of 6.0% by weight was obtained. A liquid crystal aligning agent was prepared by filtering this solution using a filter having a pore diameter of 1 μm.
(II) Evaluation of liquid crystal aligning agent (1) Evaluation of printability About the liquid crystal aligning agent prepared above, glass with a transparent electrode made of an ITO film using a liquid crystal aligning film printer (Nissha Printing Co., Ltd.) After coating on the transparent electrode surface of the substrate and heating (pre-baking) on a hot plate at 80 ° C. for 1 minute to remove the solvent, heating (post-baking) on a hot plate at 200 ° C. for 10 minutes to obtain an average film thickness A 600-mm coating film was formed. When this coating film was observed with a microscope with a magnification of 20 times to check for the presence of printing unevenness and pinholes, neither printing unevenness nor pinholes were observed, and the printability was good.

(2) Evaluation of film thickness uniformity of coating film About the coating film formed above, the film thickness at the center of the substrate and the center of 15 mm from the outer edge of the substrate using a stylus-type film thickness meter (manufactured by KLA Tencor) The film thickness at the position near the film was measured. When the film thickness difference between the two was 20 mm or less, the film thickness uniformity was evaluated as “good”, and when the film thickness difference exceeded 20 mm was evaluated as film thickness uniformity “bad”, the film uniformity was good.
(3) Manufacture of liquid crystal cell The liquid crystal aligning agent prepared above is applied to the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using a liquid crystal alignment film printing machine (manufactured by Nissha Printing Co., Ltd.). After removing the solvent by heating on a hot plate at 80 ° C. for 1 minute (pre-baking), the coating was heated on the hot plate at 200 ° C. for 10 minutes (post-baking) to form a coating film having an average film thickness of 600 mm.
The coating film is rubbed with a rubbing machine having a roll wrapped with a rayon cloth at a roll rotation speed of 500 rpm, a stage moving speed of 3 cm / sec, and a hair foot indentation length of 0.4 mm to give liquid crystal alignment ability. did. Thereafter, ultrasonic cleaning was performed in ultrapure water for 1 minute, followed by drying in a 100 ° C. clean oven for 10 minutes to obtain a substrate having a liquid crystal alignment film. This operation was repeated to obtain a pair (two) of substrates having a liquid crystal alignment film.
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 substrates having the liquid crystal alignment film, the liquid crystal alignment film surfaces are overlapped and pressure bonded. The adhesive was cured. Next, after filling nematic liquid crystal (MLC-6221 manufactured by Merck & Co., Inc.) between a pair of substrates from the liquid crystal injection port, the liquid crystal injection port is sealed with an acrylic photo-curing adhesive to produce a liquid crystal cell. did.
(3) Evaluation of heat-resistant stability About the liquid crystal cell manufactured above, a 30 Hz, 3.0 V rectangular wave on which an alternating current of 6.0 V (peak-peak) was superimposed was applied at an environmental temperature of 70 ° C. for 500 hours. When the cell after 500 hours was visually observed, when no display defect was observed, the heat stability was evaluated as “good”, and when the display defect was observed, the heat stability was evaluated as “bad”. The heat resistance stability of the liquid crystal cell was good.

Example 2
Liquid crystal alignment in the same manner as in Example 1 except that the solution containing the polyamic acid (A-1) obtained in Synthesis Example 3 was used instead of the solution containing the polyamic acid (A-1) in Example 1. When the agent was prepared and evaluated, printing unevenness and pinholes were not observed on the coating film, the printing property was good, and the coating film thickness uniformity and the heat resistance stability of the obtained liquid crystal cell were also good. It was.

Claims (3)

Tetracarboxylic dianhydride and the following formula (A)

(In Formula (A), R ^I is an alkyl group having 1 to 10 carbon atoms, a branched alkyl group having 11 to 30 carbon atoms, or an alicyclic group having 17 to 30 carbon atoms having a steroid skeleton, and R ^II is Single bond, oxygen atom, —COO— or —OOC—.)
A liquid crystal comprising at least one polymer selected from the group consisting of a polyamic acid obtained by reacting with a diamine containing a compound represented by formula (I) and a polyimide obtained by dehydrating and ring-closing the polyamic acid. Alignment agent.   The liquid crystal aligning agent of Claim 1 whose polymer is a polyimide and the imidation ratio is 30% or more. A liquid crystal display element comprising a liquid crystal alignment film formed from the liquid crystal aligning agent according to claim 1.