JP2010266477A - Liquid crystal aligner and liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal aligner for providing a liquid crystal alignment layer having high quality display and satisfactory characteristics of persistence of vision and characteristics of image sticking, and to provide a liquid crystal display element having excellent characteristics of persistence of vision and characteristics of image sticking and high voltage retention. <P>SOLUTION: The liquid crystal aligning agent contains at least one polymer selected from the group consisting of a polyamic acid and a polyimide and having a structure represented by formula (A) in at least a part of its molecule. The liquid crystal display element is provided with the liquid crystal alignment layer formed from the liquid crystal aligning agent. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid crystal aligning agent and a liquid crystal display element. More specifically, a liquid crystal aligning agent capable of forming a liquid crystal alignment film having both high-quality display, good afterimage characteristics, and image sticking characteristics, and a liquid crystal display having excellent afterimage characteristics and image sticking characteristics and high voltage holding ratio. It relates to an element.

A horizontal electric field type liquid crystal display element is a liquid crystal display element in which an electrode is formed only on the side of a pair of substrates arranged opposite to each other and an electric field is generated in a direction parallel to the substrate. Horizontal electric field type liquid crystal display elements have wider viewing angle characteristics and higher quality than conventional vertical electric field type liquid crystal display elements in which electrodes are formed on both substrates to generate an electric field in the direction perpendicular to the substrates. It is known that accurate display is possible. Such lateral electric field type liquid crystal display elements are described in Patent Documents 1 and 2 and Non-Patent Document 1, for example. Since the horizontal electric field type liquid crystal display element responds to the electric field only in the direction in which the liquid crystal molecules are parallel to the substrate, the change in the refractive index in the major axis direction of the liquid crystal molecules is not a problem. There is little change in the contrast and the contrast of the displayed color, so that high-quality display is possible regardless of the viewing angle.
However, in a horizontal electric field type liquid crystal display device, afterimage generation and image sticking become a problem during long-term use, and a liquid crystal alignment film excellent in recoverability (afterimage relaxation property) of the generated afterimage is required. In this regard, Patent Document 3 proposes a method for improving afterimage characteristics and image sticking characteristics by using a liquid crystal alignment film made of a polymer containing a large proportion of structural units derived from pyromellitic anhydride. However, when a liquid crystal alignment film containing a large number of structural units derived from pyromellitic acid anhydride is used, there is a problem that durability against long-term heat stress is impaired, and voltage holding ratio is lowered after application of heat stress. . Therefore, it is strongly desired to provide a liquid crystal alignment film that has both excellent afterimage relaxation behavior and high durability against thermal stress and surpasses a material containing a large proportion of structural units derived from pyromellitic anhydride.

U.S. Pat. No. 5,928,733 JP 56-91277 A JP 2008-15497 A JP-A-6-222366 JP-A-6-281937 JP-A-5-107544 JP 2003-214983 A

“Liq. Cryst.”, Vol. 22, p379 (1996)

The present invention has been made in view of the above circumstances, and the object thereof is a liquid crystal alignment film in which high-quality display, good afterimage characteristics, and image sticking characteristics are compatible, particularly in a liquid crystal display element of a horizontal electric field type. It is in providing the liquid crystal aligning agent which gives.
Another object of the present invention is to provide a liquid crystal display device that achieves both high-quality display and good afterimage characteristics and image sticking characteristics.
Still other objects and advantages of the present invention will become apparent from the following description.

In accordance with the present invention, the above objects and advantages of the present invention are primarily as follows:
At least one polymer selected from the group consisting of polyamic acid and polyimide, provided that at least a part of the polymer has the following formula (A)

It is achieved by the liquid crystal aligning agent containing which has the structure represented by these.
The above objects and advantages of the present invention are, secondly,
This is achieved by a liquid crystal display device comprising a liquid crystal alignment film formed from the above liquid crystal aligning agent.

The liquid crystal aligning agent of the present invention provides a liquid crystal alignment film in which a wide viewing angle characteristic and high-quality display, and a good afterimage characteristic and image sticking characteristic are compatible. Therefore, the liquid crystal display element of the present invention having a liquid crystal alignment film formed from such a liquid crystal aligning agent has both high-quality display and good afterimage characteristics and image sticking characteristics.
The liquid crystal aligning agent of the present invention exhibits its advantageous effects to the maximum when used in a liquid crystal display element of a horizontal electric field type. Therefore, the liquid crystal display element of the present invention is preferably a horizontal electrolysis type liquid crystal display element. is there.
The liquid crystal display element of the present invention (preferably a lateral electrolysis type liquid crystal display element) can be effectively applied to various devices, such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, portable information. It can be suitably used for display devices such as terminals, digital cameras, mobile phones, various monitors, and liquid crystal televisions.

Schematic which shows the structure of the comb-tooth shaped transparent electrode pattern in the horizontal electric field system liquid crystal display element of an Example.

Hereinafter, the present invention will be described in detail.
The liquid crystal aligning agent of the present invention is at least one polymer selected from the group consisting of polyamic acid and polyimide, provided that the polymer has a structure represented by the above formula (A) in at least a part of its molecule. It has. Hereinafter, such a polymer is referred to as “specific polymer” in the present specification. In the specific polymer, the structure represented by the above formula (A) may be present in the main chain of the polymer, may be present in the side chain of the polymer, or may be present in the polymer. It may be present in both the main chain and the side chain.
The polyamic acid having a structure represented by the above formula (A) in at least a part of the molecule includes, for example, a tetracarboxylic acid containing a compound represented by the above formula (A) and a compound having two carboxylic anhydride groups. Obtained by reacting a dianhydride with a diamine or reacting a tetracarboxylic dianhydride with a diamine containing a compound having the structure represented by the above formula (A) and two amino groups. Can
A polyimide having a structure represented by the above formula (A) in at least a part of the molecule can be obtained, for example, by dehydrating and ring-closing the polyamic acid obtained as described above.
As a specific polymer contained in the liquid crystal aligning agent of the present invention, a tetracarboxylic dianhydride is reacted with a diamine containing a compound having a structure represented by the above formula (A) and two amino groups. The polyamic acid obtained in this manner and at least one polymer selected from the group consisting of polyimides obtained by dehydrating and ring-closing the polyamic acid are preferred.
<Polyamic acid>
As described above, a preferred polyamic acid in the present invention is obtained by reacting a tetracarboxylic dianhydride with a diamine containing a compound represented by the above formula (A) and a compound having two amino groups. is there.
[Tetracarboxylic dianhydride]
Examples of the tetracarboxylic dianhydride used for the synthesis of the polyamic acid include butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 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-tricarboxycyclo Ntylacetic 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, 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 anhydride, 3,5,6-tricarboxy- 2-carboxymethylnorbornane-2: 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone, The following formulas (TI) and (T-II)

(In the formulas (T-I) and (T-II), R ¹ and R ³ are each a divalent organic group having an aromatic ring, and R ² and R ⁴ are each a hydrogen atom or an alkyl group. And a plurality of R ² and R ⁴ may be the same or different.)
An aliphatic tetracarboxylic dianhydride and an 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 ( And aromatic tetracarboxylic dianhydrides such as anhydrotrimellitate. The benzene ring of the aromatic tetracarboxylic dianhydride may be substituted with one or two or more alkyl groups having 1 to 4 carbon atoms (preferably a methyl group).
These tetracarboxylic dianhydrides can be used singly or in combination of two or more.

As tetracarboxylic dianhydride used for the synthesis of polyamic acid in the present invention, among the above, butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3 -Dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic 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, 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, , 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 anhydride, 3,5, 6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8 , 10-tetraone, 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, the following formulas (T-1) to (T-3) among the compounds represented by the above formula (TI)

And the following formula (T-4) among the compounds represented by formula (T-II)

By using at least one selected from the group consisting of compounds represented by the following (hereinafter referred to as “specific tetracarboxylic dianhydride”), the formed liquid crystal alignment film exhibits good liquid crystal alignment. It is preferable from the viewpoint that it can be performed.
More preferably, the specific tetracarboxylic dianhydride is 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, 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-dicarbo Acid anhydride, 3,5,6-tricarboxy-2-carboxymethyl norbornane -2: 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^{2, 6} ] At least one selected from the group consisting of undecane-3,5,8,10-tetraone, pyromellitic dianhydride and the compound represented by the above formula (T-1), more preferably 2 , 3,5-Tricarboxycyclopentylacetic acid dianhydride, pyromellitic dianhydride, 2,3,2 ′, 3′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetra Carboxylic dianhydride, 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,3,3a, 4,5 9b-Hexahydro-8-methyl-5 (Tetrahydro-2,5-dioxo-3-furanyl) - naphtho [1,2-c] - is small with one selected from the group consisting of furan-1,3-dione.

The tetracarboxylic dianhydride used in the synthesis of the polyamic acid in the present invention contains 50 mol% or more of the specific tetracarboxylic dianhydride as described above with respect to the total tetracarboxylic dianhydride. Preferably, it is more preferably 70 mol% or more, and particularly preferably 80 mol% or more.
As the specific tetracarboxylic dianhydride, in particular, 2,3,5-tricarboxycyclopentylacetic acid dianhydride,
Pyromellitic dianhydride, 2,3,2 ′, 3′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 3,4,3 ′, 4'-biphenyltetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic 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 is preferably included. In this case, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride is preferably contained in an amount of 50 mol% or more, more preferably 70 mol% or more based on the total specific tetracarboxylic dianhydride. In particular, it is preferable to contain 90 mol% or more.
The tetracarboxylic dianhydride used for the synthesis of the polyamic acid in the present invention is most preferably composed of only the specific tetracarboxylic dianhydride as described above.

[Diamine]
The diamine used for synthesizing a preferred polyamic acid in the present invention includes a structure represented by the above formula (A) and a compound having two amino groups (hereinafter referred to as “compound (A)”).
Examples of the compound (A) include the following formulas (A-1) to (A-3):

(In the above formulas (A-1) to (A-3), R ^I is an alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, respectively. A hydroxyl group, a carboxyl group, a cyano group or an acyl group, each of R ^II is a single bond or a divalent aromatic group having 4 to 20 carbon atoms, a is an integer of 0 to 3, and b is , 0 or 1 respectively.)
The compound represented by each of these can be mentioned.
Examples of the R ¹ alkyl group in the above formulas (A-1) to (A-3) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. The cycloalkyl group of R ¹ is a concept including both a monocyclic group and a polycyclic group. For example, a cyclopentyl group, a cyclohexyl group, a 2-norbornyl group, a bicyclo [2.2.2] oct-1-yl Group, decahydronaphthalen-2-yl group and the like. Examples of the R ¹ alkoxyl group include a methoxyl group, an ethoxyl group, a propoxyl group, and a butoxyl group.
The divalent aromatic group having 4 to 20 carbon atoms of R ^{II in} the above formulas (A-1) to (A-3) is an arylene group having 6 to 20 carbon atoms (divalent aromatic carbon hydrogen group). And a divalent heteroaromatic group having 4 to 20 carbon atoms, and examples of the arylene group include a 1,4-phenylene group and a 1,3-phenylene group;
Examples of the divalent heteroaromatic group include a 2,4-pyridyl group, a 2,5-pyridyl group, a 2,5-furandiyl group, a 2,5-thiophenediyl group, and the like.
A in the formula (A-1) is 0 or 1;
In the above formulas (A-2) and (A-3), b is preferably 0, respectively.
Specific examples of the compound (A) include, for example, 2- (4-aminophenyl) -6-aminobenzoxazole, 4- (6-aminobenzoxazolo) -4′-aminobiphenyl, 2- (4-amino Phenyl) -5-methylbenzoxazol-6-ylamine, 2- (4-aminophenyl) -7-methylbenzoxazol-5-ylamine, 2- (4-aminophenyl) -6-aminobenzo [1,2-d 4,5-d ′] bisoxazole and the like. Among these, 2- (4-aminophenyl) -6-6 is particularly preferable from the viewpoint of improving the afterimage characteristics of the liquid crystal alignment film to be formed. Aminobenzoxazole is preferred.

As a diamine for synthesizing a preferred polyamic acid in the present invention, only the compound (A) may be used alone, or the compound (A) and other diamines may be used in combination.
Examples of other diamines that can be used here include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, 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'-dimethyl-4,4'-diaminobiphenyl, 5-amino-1- (4'-aminophenyl) -1,3,3-trimethylindane, 6-amino-1- (4'-aminophenyl)- 1,3,3-trimethylindane, 3,4'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, 3,4'- Aminobenzophenone, 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, bis [4- (4-aminophenoxy) phenyl] sulfone, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4- Aminophenoxy) biphenyl, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -10-hydroanthracene, 2, 7-diaminofluorene, 9,9-dimethyl-2,7-diaminofluorene, 9,9-bis (4-aminophenyl) fluorene Orene, bis (4-amino-2-chlorophenyl) methane, 2,2 ′, 5,5′-tetrachloro-4,4′-diaminobiphenyl, 2,2′-dichloro-4,4′-diamino-5 , 5′-dimethoxybiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 4,4 ′-(p-phenylenediisopropylidene) bisaniline, 4,4 ′-(m-phenylenediisopropylidene) Bisaniline, 2,2′-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4′-diamino-3,3′-bis (trifluoromethyl) biphenyl, 4 , 4′-Diamino-2,2′-bis (trifluoromethyl) biphenyl, 4,4′-bis [(4-amino-2-trifluoromethyl) phenoxy] -octafluorobiphe Nil, the following formulas (D-1) and (D-2)

(Y in formula (D-1) is an integer of 2 to 12, and z in formula (D-2) is an integer of 1 to 5.)
An aromatic diamine such as a compound represented by each of the following:
1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 1,4-diaminocyclohexane, isophoronediamine, Tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindanylene methylenediamine, tricyclo [6.2.1.0 ^2,7 ] -undecylenediethylenediamine, 4,4′-methylenebis (cyclohexylamine) ), 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane and other aliphatic and alicyclic diamines;
2,3-diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 5,6-diamino-2,3-dicyanopyrazine, 5,6-diamino-2,4 -Dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 1,4-bis (3-aminopropyl) piperazine, 2,4-diamino-6-isopropoxy-1,3 , 5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine, 2,4-diamino-6-methyl -S-triazine, 2,4-diamino-1,3,5-triazine, 4,6-diamino-2-vinyl-s-triazine, 2,4-diamino-5-phenylthiazole, 2,6- Aminopurine, 5,6-diamino-1,3-dimethyluracil, 3,5-diamino-1,2,4-triazole, 3,8-diamino-6-phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, N, N′-bis (4-aminophenyl) phenylamine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole N-phenyl-3,6-diaminocarbazole, N, N′-bis (4-aminophenyl) -benzidine, N, N′-bis (4-aminophenyl) -N, N′-dimethyl-benzidine and Formulas (DI) and (D-II)

(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 a divalent group. An organic group;
In the formula (D-II), R ⁶ 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 X ² is 2 And a plurality of X ² may be the same or different. )
A diamine having two primary amino groups in the molecule and a nitrogen atom other than the primary amino group, such as a compound represented by each of:
The following formula (D-III)

(In formula (D-III), each R ⁷ is a hydrocarbon group having 1 to 12 carbon atoms, and a plurality of R ⁷ may be the same or different, and p is each 1 is an integer of 1 to 3, and q is an integer of 1 to 20.)
And diaminoorganosiloxanes such as compounds represented by the formula: The benzene rings of the aromatic diamine and the diamine having two primary amino groups and a nitrogen atom other than the primary amino group in the molecule are each one or more alkyl groups having 1 to 4 carbon atoms. (Preferably a methyl group) may be substituted.
These other diamines can be used alone or in combination of two or more.

  Other diamines that can be used to synthesize the polyamic acid in the present invention include p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulfide, 1,5- Diaminonaphthalene, 2,2′-dimethyl-4,4′-diaminobiphenyl, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 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 ′-( -Phenylenediisopropylidene) bisaniline, 4,4 '-(m-phenylenediisopropylidene) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, 1,4-diaminocyclohexane, 4,4′-methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane, compounds represented by the above formulas (D-1) and (D-2), 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′-bi Of the compounds represented by (4-aminophenyl) -benzidine, N, N′-bis (4-aminophenyl) -N, N′-dimethylbenzidine, the above formula (D-II), the following formula (D— 3)

And at least one selected from the group consisting of 1,3-bis (3-aminopropyl) -tetramethyldisiloxane among the compounds represented by formula (D-III) and "Other specific diamines") are preferred.
Other particularly preferred diamines are p-phenylenediamine, 3,5-diaminobenzoic acid, 3,5-diaminobenzoic acid methyl ester, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 1,4 Selected from the group consisting of -bis (4-aminophenyl) piperazine, 2,2'-dimethyl-4,4'-diaminobiphenyl and 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl At least one kind.
The diamine used for synthesizing a preferred polyamic acid in the present invention preferably contains 0.1 mol% or more, and 1 to 40 mol% of the above compound (A) with respect to the total diamine. More preferably, it is particularly preferable to contain 5 to 20 mol%. The diamine used in the present invention preferably contains other specific diamine as described above in addition to the compound (A). In this case, the use ratio of the other specific diamine is preferably 30 to 99.9 mol%, more preferably 50 to 99 mol%, particularly 80 to 95 mol%, based on the total diamine. It is preferable that
The diamine used for synthesizing the polyamic acid in the present invention is preferably composed only of the above compound (A) and other specific diamine.

[Synthesis of polyamic acid]
The preferable polyamic acid in this invention can be obtained by making tetracarboxylic dianhydride and the diamine containing a compound (A) react.
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. It takes 5 to 12 hours.
Examples of the organic solvent that can be used in the synthesis of the polyamic acid include an aprotic polar solvent, phenol and derivatives thereof, alcohol, ketone, ester, ether, halogenated hydrocarbon, hydrocarbon and the like.

Examples of the aprotic polar solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide and the like. ;
Examples of the phenol derivative include m-cresol, xylenol, halogenated phenol and the like;
Examples of the alcohol include methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, and ethylene glycol monomethyl ether;
Examples of the ketone include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone;
Examples of the ester include ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, and diethyl malonate;
Examples of the ether include 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, etc .;
Examples of the halogenated hydrocarbon include dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene and the like;
Examples of the hydrocarbon include hexane, heptane, octane, benzene, toluene, xylene, isoamylpropionate, isoamylisobutyrate, and diisopentyl ether.

Among these organic solvents, one or more selected from the group consisting of aprotic polar solvents and phenol and derivatives thereof (first group organic solvent), or one selected from the first group of organic solvents It is preferable to use a mixture of the above and one or more selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons (second group organic solvent). In the latter case, the use ratio of the second group of organic solvents is preferably 50% by weight or less, more preferably 40% by weight or less, with respect to the total of the first group of organic solvents and the second group of organic solvents. Furthermore, it is preferable that it is 30 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.
When polyamic acid is dehydrated and cyclized into a polyimide, the above reaction solution may be directly subjected to dehydration and cyclization reaction, or may be subjected to dehydration and cyclization reaction after isolating the polyamic acid contained in the reaction solution. Alternatively, the isolated polyamic acid may be purified and then subjected to a dehydration ring closure reaction.
The polyamic acid is 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 off the solvent in the reaction solution under reduced pressure using an evaporator. It can be carried out. 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 evaporating under reduced pressure with an evaporator once or several times.

<Polyimide>
A preferred polyimide in 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 kind of preferable tetracarboxylic dianhydride and its preferable usage rate are the same as in the case of polyamic acid.
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 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 a compound (A), may use only a compound (A), a compound (A) and said other A diamine may be used in combination. The types of other preferred diamines and the preferred use ratio of each diamine are the same as in the case of polyamic acid.
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 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 50% or more, and particularly preferably 70% 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 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. 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. The reaction time is preferably 1.0 to 24 hours, more preferably 1.0 to 12 hours.
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 120 hours, more preferably 2.0 to 30 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 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 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 dehydration ring closure 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 preferred polyamic acid and polyimide in the present invention may each be a terminal-modified polymer having a controlled molecular weight. By using such a 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-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride, n -Hexadecyl succinic anhydride etc .;
Examples of the monoamine compound include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine and the like; Examples of the isocyanate compound include phenyl isocyanate and naphthyl isocyanate.
The use ratio of the molecular weight modifier is preferably 20 parts by weight or less, more preferably 10 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 has 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 aligning agent of the present invention preferably contains the specific polymer as described above as an essential component, but may contain other components as necessary. Examples of such other components include other polymers and adhesion improvers.
These other polymers can be used to improve solution and electrical properties. Such other polymer is a polymer other than the specific polymer as described above. For example, a polyamic acid (hereinafter referred to as “others”) obtained by reacting tetracarboxylic dianhydride with a diamine not containing the compound (A). Polyamic acid ”), polyimide obtained by dehydrating and ring-closing the polyamic acid (hereinafter referred to as“ other polyimide ”), polyamic acid ester, polyester, polyamide, polysiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly (Styrene-phenylmaleimide) derivatives, poly (meth) acrylates and the like. Of these, other polyamic acids or other polyimides are preferred, and other polyamic acids are more preferred.
The proportion of the other polymer used is preferably 50% by weight or less, more preferably 0. 0% by weight based on the total amount of the polymers (referring to the total of the specific polymer and other polymers, hereinafter the same). It is preferably 1 to 40% by weight, and more preferably 0.1 to 30% by weight.

Examples of the adhesion improver include a compound having at least one epoxy group in the molecule (hereinafter referred to as “epoxy compound”), a functional silane compound, and the like.
The epoxy compound is preferably an epoxy compound having at least two epoxy groups in the molecule, such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diester. Glycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, N, N, N ′ , N′-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexa N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane, N, N-diglycidyl-benzylamine, N, N-diglycidyl-aminomethylcyclohexane, N, N-diglycidyl-cyclohexylamine, etc. Can be mentioned as preferred.
The compounding ratio of these epoxy 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-trimethoxysilyl-3,6-diazanonyl acetate, 9- Triethoxysilyl-3,6-diazanonyl acetate, methyl 9-trimethoxysilyl-3,6-diazananoate, methyl 9-triethoxysilyl-3,6-diazananoate, N-benzyl-3-aminopropyltri Methoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, glycidoxymethyltrimethoxysilane, glycidoxy Methyltriethoxysilane, 2-glycidoxyethyltrimeth Shishiran, 2-glycidoxyethyl triethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropyl triethoxy silane and the like.
The blending ratio of these functional silane compounds is preferably 2 parts by weight or less, more preferably 0.02 to 0.2 parts by weight with respect to 100 parts by weight of the total amount of the polymer.

The liquid crystal aligning agent of the present invention is constituted by dissolving the specific polymer as described above and other additives optionally blended as required, preferably dissolved in an organic solvent.
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 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, diisopentyl ether, ethylene carbonate, propylene carbonate, etc. Can be mentioned. These can be used alone or in combination 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 wt%. 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 solid content concentration range varies depending on the method used when applying the liquid crystal aligning agent 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 10 to 50 degreeC, More preferably, it is 20 to 30 degreeC.
The liquid crystal aligning agent of the present invention thus obtained can be suitably used particularly for forming a liquid crystal alignment film of a horizontal electrolysis type liquid crystal display element.

<Liquid crystal display element>
The liquid crystal display element of the present invention is a liquid crystal display element comprising a liquid crystal alignment film formed from the liquid crystal aligning agent of the present invention as described above, preferably a horizontal electrolysis type liquid crystal display element.
Such a horizontal electric field type liquid crystal display element can be produced by, for example, the following steps (1) to (3) using the liquid crystal aligning agent of the present invention.
(1) First, the liquid crystal aligning agent of this invention is apply | coated on a board | substrate, Then, a coating film is formed on a board | substrate by heating an application surface.
Here, as a substrate, a pair of a conductive film formation surface of a substrate on which a transparent conductive film patterned in a comb-teeth shape is provided and a substrate on which the conductive film is not provided is provided as a pair. The liquid crystal aligning agent of the present invention is preferably a roll coater on the conductive film forming surface of the substrate provided with the transparent conductive film patterned in a tooth shape and on one side of the substrate (counter substrate) not provided with the conductive film. A coating film is formed by coating each of the coated surfaces by a method, a spinner method or an ink jet printing method, and then heating each coated surface.
Examples of the material constituting the substrate include glass such as float glass and soda glass; plastics such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly (alicyclic olefin). As the transparent conductive film provided on one surface of the substrate on one side, 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 ) In order to obtain a patterned transparent conductive film, for example, a method of forming a pattern by photo-etching after forming a transparent conductive film without a pattern, a desired pattern when forming a transparent conductive film, etc. For example, a method using a mask having the same 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.

After application of the liquid crystal aligning agent, preheating (pre-baking) is preferably performed for the purpose of preventing dripping of the applied aligning agent. The pre-bake temperature is preferably 30 to 200 ° C, more preferably 40 to 150 ° C, and particularly preferably 40 to 100 ° C. The pre-bake time is preferably 0.25 to 10 minutes, more preferably 0.5 to 5 minutes. Then, a baking (post-baking) process is implemented for the purpose of removing a solvent completely, and heat imidizing a polyamic acid as needed. The firing (post-bake) temperature is preferably 80 to 300 ° C, more preferably 120 to 250 ° C, and the post-bake time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. Thus, the film thickness of the formed film is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm.
Although the liquid crystal aligning agent of this invention forms the coating film used as a liquid crystal aligning film by removing an organic solvent after application | coating as mentioned above, the liquid crystal aligning agent of this invention is polyamic acid or an imide ring structure, and an amic acid. In the case of containing a polyimide having both a structure and a coating film, the film may be further heated to cause the dehydration ring-closing reaction to proceed to form a more imidized coating film.

(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 liquid crystal molecules is imparted to the coating film to form a liquid crystal orientation film.
Further, for the liquid crystal alignment film formed as described above, for example, a liquid crystal as shown in Patent Document 4 (JP-A-6-222366) and Patent Document 5 (JP-A-6-281937). A process for changing the pretilt angle of a part of the liquid crystal alignment film by irradiating a part of the alignment film with ultraviolet rays, or a liquid crystal alignment as disclosed in Patent Document 6 (Japanese Patent Laid-Open No. 5-107544). A resist film is formed on a part of the film surface, then the rubbing process is performed in a direction different from the previous rubbing process, and then the resist film is removed so that the liquid crystal alignment film has different liquid crystal alignment capabilities in each region. It is possible to further improve the visual field characteristics of the liquid crystal display element obtained.

(3) A liquid crystal cell is manufactured by preparing two substrates on which a liquid crystal alignment film is formed as described above, and disposing a liquid crystal between the two substrates opposed to each other. Here, the two substrates are arranged to face each other so that the rubbing directions in each coating film are at a predetermined angle, for example, orthogonal or antiparallel.
In order to manufacture a liquid crystal cell, the following two methods are mentioned, for example.
The first method is a conventionally known method. First, two substrates are arranged to face each other through a gap (cell gap) so that the respective liquid crystal alignment films are opposed to each other, and the peripheral portions of the two substrates are bonded using a sealant, and the substrate surface and the sealant are bonded. A liquid crystal cell can be manufactured by injecting and filling liquid crystal into the cell gap partitioned by the step, and then sealing the injection hole.
The second method is a method called an ODF (One Drop Fill) method. For example, an ultraviolet light curable sealing material is applied to a predetermined location on one of the two substrates on which the liquid crystal alignment film is formed, and liquid crystal is dropped on the liquid crystal alignment film surface. The other substrate is bonded so as to face each other, and then the entire surface of the substrate is irradiated with ultraviolet light to cure the sealant, whereby a liquid crystal cell can be manufactured.
Regardless of which method is used, the liquid crystal cell produced as described above is further heated to a temperature at which the liquid crystal used takes an isotropic phase, and then gradually cooled to room temperature, so that the flow alignment during liquid crystal injection is achieved. It is desirable to remove.
And the liquid crystal display element of this invention can be obtained by bonding a polarizing plate on the outer surface of a liquid crystal cell.

Here, as the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used.
As the liquid crystal, for example, a nematic liquid crystal, a smectic liquid crystal, and the like can be used. Among these, a nematic liquid crystal is preferable. For example, a Schiff base liquid crystal, an azoxy liquid crystal, a biphenyl liquid crystal, a phenyl cyclohexane liquid crystal, and an ester liquid crystal. Terphenyl liquid crystal, biphenyl cyclohexane liquid crystal, pyrimidine liquid crystal, dioxane liquid crystal, bicyclooctane liquid crystal, cubane liquid crystal, 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 (Merck); Ferroelectric liquid crystals such as siloxybenzylidene-p-amino-2-methylbutylcinnamate may be further added and used.
As a polarizing plate 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 stretching and aligning polyvinyl alcohol is sandwiched between protective films of cellulose acetate 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.
In addition, in the following synthesis example, 2- (4-aminophenyl) -6-aminobenzoxazole used the commercial item by Wakayama Seika Kogyo Co., Ltd. as it was.
Further, the solution viscosity (mPa · s) of the polymer in each synthesis example was measured at 25 ° C. using a predetermined solvent and the polymer solution having the concentration described in each synthesis example using an E-type viscometer. It is the value.

<Synthesis of specific polymer>
[Synthesis of polyamic acid having a structure represented by the above formula (A)]
Synthesis example 1
150 g (0.50 mol) of 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride as tetracarboxylic dianhydride and 45 g of 2- (4-aminophenyl) -6-aminobenzoxazole as diamine ( 0.20 mol), 40 g (0.20 mol) of 4,4′-diaminodiphenyl ether and 27 g (0.10 mol) of N, N′-bis (4-aminophenyl) piperazine were added to N-methyl-2-pyrrolidone 2 , 300 g and reacted at room temperature for 6 hours to obtain a solution containing 10% by weight of polyamic acid (A-1) having a solution viscosity of 110 mPa · s.
Synthesis example 2
150 g (0.50 mol) of 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride as tetracarboxylic dianhydride and 45 g of 2- (4-aminophenyl) -6-aminobenzoxazole as diamine ( 0.20 mol), 4,4′-diaminodiphenyl ether 20 g (0.10 mol), N, N′-bis (4-aminophenyl) piperazine 27 g (0.10 mol) and 3,5-diaminobenzoic acid 15 g (0.10 mol) is dissolved in 2,300 g of N-methyl-2-pyrrolidone and reacted at room temperature for 6 hours to contain 10% by weight of polyamic acid (A-2) having a solution viscosity of 80 mPa · s. Got.

[Synthesis of polyimide having the structure represented by the above formula (A)]
Synthesis example 3
110 g (0.50 mol) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride as tetracarboxylic dianhydride and 11 g (0.050 mol) of 2- (4-aminophenyl) -6-aminobenzoxazole as diamine ), 3,5-diaminobenzoic acid 38 g (0.25 mol), p-phenylenediamine 14 g (0.13 mol), 4,4′-diaminodiphenyl ether 10 g (0.050 mol) and N, N′-bis By dissolving 6.7 g (0.025 mol) of (4-aminophenyl) piperazine in 1,700 g of N-methyl-2-pyrrolidone and reacting at 60 ° C. for 6 hours, a polyamic acid having a solution viscosity of 60 mPa · s was obtained. A solution containing was obtained.
Next, 820 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 400 g of pyridine and 310 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 substituted with γ-butyrolactone, and then concentrated to obtain 1,200 g of a solution containing 15% by weight of polyimide (B-1) having an imidization ratio of about 85%. . A small amount of this solution was collected, and γ-butyrolactone was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 6.0% by weight was 20 mPa · s.

Synthesis example 4
110 g (0.50 mol) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride as tetracarboxylic dianhydride and 11 g (0.050 mol) of 2- (4-aminophenyl) -6-aminobenzoxazole as diamine ), 3,5-diaminobenzoic acid 46 g (0.30 mol), p-phenylenediamine 5.4 g (0.050 mol), 4,4′-diaminodiphenyl ether 10 g (0.050 mol) and N, N ′ -By dissolving 13 g (0.050 mol) of bis (4-aminophenyl) piperazine in 1,880 g of N-methyl-2-pyrrolidone and reacting at 60 ° C. for 6 hours, a polyamic acid having a solution viscosity of 64 mPa · s was obtained. A solution containing was obtained.
Next, 850 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 400 g of pyridine and 310 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with γ-butyrolactone, and then concentrated to obtain 1,200 g of a solution containing 15% by weight of polyimide (B-2) having an imidation ratio of about 87%. . A small amount of this solution was collected, and γ-butyrolactone was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 6.0% by weight was 22 mPa · s.

Synthesis example 5
110 g (0.50 mol) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride as tetracarboxylic dianhydride and 5.6 g (0.2 g) of 2- (4-aminophenyl) -6-aminobenzoxazole as diamine. 025 mol), 3,5-diaminobenzoic acid 46 g (0.30 mol), p-phenylenediamine 11 g (0.10 mol), 4,4′-diaminodiphenyl ether 10 g (0.050 mol) and N, N ′. -Polyamics having a solution viscosity of 75 mPa · s by dissolving 6.7 g (0.025 mol) of bis (4-aminophenyl) piperazine in 1,700 g of N-methyl-2-pyrrolidone and reacting at 60 ° C. for 6 hours A solution containing acid was obtained.
Next, 820 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 400 g of pyridine and 310 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 γ-butyrolactone, and then concentrated to obtain 1,200 g of a solution containing 15% by weight of polyimide (B-3) having an imidization ratio of about 90%. . A small amount of this solution was collected, and γ-butyrolactone was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 6.0% by weight was 32 mPa · s.

<Synthesis of other polymers>
[Synthesis of other polyamic acids]
Comparative Synthesis Example 1
120 g (0.40 mol) of 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride as tetracarboxylic dianhydride, 22 g (0.10 mol) of pyromellitic anhydride and p-phenylene as diamine 22 g (0.20 mol) of diamine, 40 g (0.20 mol) of 4,4′-diaminodiphenyl ether and 27 g (0.10 mol) of N, N′-bis (4-aminophenyl) piperazine were added to N-methyl-2. -A solution containing 10% by weight of polyamic acid (a-1) having a solution viscosity of 120 mPa · s was obtained by dissolving in 2,300 g of pyrrolidone and reacting at room temperature for 6 hours.
Comparative Synthesis Example 2
120 g (0.40 mol) of 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride as tetracarboxylic dianhydride, 22 g (0.10 mol) of pyromellitic anhydride and p-phenylene as diamine 22 g (0.20 mol) of diamine, 40 g (0.20 mol) of 4,4′-diaminodiphenyl ether, 27 g (0.10 mol) of N, N′-bis (4-aminophenyl) piperazine and 3,5-diaminobenzoic acid 15% (0.10 mol) of acid is dissolved in 2,200 g of N-methyl-2-pyrrolidone and reacted at room temperature for 6 hours, thereby containing 10% by weight of polyamic acid (a-2) having a solution viscosity of 94 mPa · s. A solution was obtained.

Comparative Synthesis Example 3
150 g (0.50 mol) of 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride as tetracarboxylic dianhydride and 22 g (0.20 mol) of p-phenylenediamine as diamine, 4,4 ′ -40 g (0.20 mol) of diaminodiphenyl ether and 27 g (0.10 mol) of N, N'-bis (4-aminophenyl) piperazine were dissolved in 2,100 g of N-methyl-2-pyrrolidone and stirred at room temperature for 6 hours. By making it react, the solution containing 10 weight% of polyamic acids (a-3) with a solution viscosity of 110 mPa * s was obtained.
Comparative Synthesis Example 4
150 g (0.50 mol) of 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride as tetracarboxylic dianhydride and 22 g (0.20 mol) of p-phenylenediamine as diamine, 4,4 ′ -20 g (0.10 mol) of diaminodiphenyl ether, 27 g (0.10 mol) of N, N′-bis (4-aminophenyl) piperazine and 15 g (0.10 mol) of 3,5-diaminobenzoic acid were mixed with N-methyl A solution containing 10% by weight of polyamic acid (a-4) having a solution viscosity of 78 mPa · s was obtained by dissolving in 2,100 g of -2-pyrrolidone and reacting at room temperature for 6 hours.

[Synthesis of other polyimides]
Comparative Synthesis Example 5
100 g (0.45 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride, 11 g (0.050 mol) of pyromellitic anhydride and 3,5-diaminobenzoic acid as diamine 38 g (0.25 mol), p-phenylenediamine 19 g (0.18 mol), 4,4′-diaminodiphenyl ether 10 g (0.050 mol) and N, N′-bis (4-aminophenyl) piperazine 7 g (0.025 mol) was dissolved in 1,700 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours to obtain a solution containing polyamic acid having a solution viscosity of 75 mPa · s.
Next, 820 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 400 g of pyridine and 310 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 γ-butyrolactone, and then concentrated to obtain 1,000 g of a solution containing 15% by weight of polyimide (b-1) having an imidation ratio of about 87%. . A small amount of this solution was collected, and γ-butyrolactone was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 6.0% by weight was 24 mPa · s.

Comparative Synthesis Example 6
100 g (0.45 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride, 11 g (0.050 mol) of pyromellitic anhydride and 3,5-diaminobenzoic acid as diamine 46 g (0.30 mol), p-phenylenediamine 11 g (0.10 mol), 4,4′-diaminodiphenyl ether 10 g (0.050 mol) and N, N′-bis (4-aminophenyl) piperazine 13 g ( 0.050 mol) was dissolved in 1,700 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours to obtain a solution containing a polyamic acid having a solution viscosity of 92 mPa · s.
Next, 850 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 400 g of pyridine and 310 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 γ-butyrolactone and then concentrated to obtain 1,200 g of a solution containing 15% by weight of polyimide (b-2) having an imidization ratio of about 88%. . A small amount of this solution was collected, and γ-butyrolactone was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 6.0% by weight was 25 mPa · s.

Comparative Synthesis Example 7
100 g (0.45 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride, 11 g (0.050 mol) of pyromellitic anhydride and 3,5-diaminobenzoic acid as diamine 46 g (0.30 mol), p-phenylenediamine 14 g (0.13 mol), 4,4′-diaminodiphenyl ether 10 g (0.050 mol) and N, N′-bis (4-aminophenyl) piperazine 7 g (0.025 mol) was dissolved in 1,700 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours to obtain a solution containing polyamic acid having a solution viscosity of 78 mPa · s.
Next, 820 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 400 g of pyridine and 310 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 γ-butyrolactone and then concentrated to obtain 1,200 g of a solution containing 15% by weight of polyimide (b-3) having an imidation ratio of about 93%. . A small amount of this solution was collected, and γ-butyrolactone was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 6.0% by weight was 37 mPa · s.

Comparative Synthesis Example 8
110 g (0.50 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride, 38 g (0.25 mol) of 3,5-diaminobenzoic acid as diamine, 19 g of p-phenylenediamine (0.18 mol), 10 g (0.050 mol) of 4,4′-diaminodiphenyl ether and 6.7 g (0.025 mol) of N, N′-bis (4-aminophenyl) piperazine were added to N-methyl-2. -A solution containing polyamic acid having a solution viscosity of 55 mPa · s was obtained by dissolving in 1,600 g of pyrrolidone and reacting at 60 ° C for 6 hours.
Next, 780 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 400 g of pyridine and 310 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with γ-butyrolactone and then concentrated to obtain 1,100 g of a solution containing 15% by weight of polyimide (b-4) having an imidization ratio of about 84%. . A small amount of this solution was collected, and γ-butyrolactone was added to measure the solution viscosity as a solution having a polyimide concentration of 6.0% by weight, which was 21 mPa · s.

Comparative Synthesis Example 9
110 g (0.50 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride, 46 g (0.30 mol) of 3,5-diaminobenzoic acid as diamine, 11 g of p-phenylenediamine (0.10 mol), 10 g (0.050 mol) of 4,4′-diaminodiphenyl ether and 13 g (0.050 mol) of N, N′-bis (4-aminophenyl) piperazine were added to N-methyl-2-pyrrolidone. A solution containing polyamic acid having a solution viscosity of 60 mPa · s was obtained by dissolving in 1,700 g and reacting at 60 ° C. for 6 hours.
Next, 820 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 400 g of pyridine and 310 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 γ-butyrolactone, and then concentrated to obtain 1,200 g of a solution containing 15% by weight of polyimide (b-5) having an imidation ratio of about 91%. . A small amount of this solution was collected, and γ-butyrolactone was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 6.0% by weight was 23 mPa · s.

Comparative Synthesis Example 10
110 g (0.50 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride, 46 g (0.30 mol) of 3,5-diaminobenzoic acid as diamine, 14 g of p-phenylenediamine (0.13 mol), 10 g (0.050 mol) of 4,4′-diaminodiphenyl ether and 6.7 g (0.025 mol) of N, N′-bis (4-aminophenyl) piperazine were added to N-methyl-2. -A solution containing polyamic acid having a solution viscosity of 71 mPa · s was obtained by dissolving in 1,700 g of pyrrolidone and reacting at 60 ° C for 6 hours.
Next, 810 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 400 g of pyridine and 310 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 γ-butyrolactone, and then concentrated to obtain 1,200 g of a solution containing 15% by weight of polyimide (b-6) having an imidation ratio of about 89%. . A small amount of this solution was collected, and γ-butyrolactone was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 6.0% by weight was 31 mPa · s.

Example 1
<Preparation of liquid crystal aligning agent>
In the solution containing the polyamic acid (A-1) obtained in Synthesis Example 1 above, N-methyl-2-pyrrolidone and butyl cellosolve were used, and the weight ratio of N-methyl-2-pyrrolidone: butyl cellosolve was 80:20. In addition, 2 parts by weight of N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane, which is an epoxy compound, is added as an adhesion improver to obtain a solid content concentration of 3.5% by weight. % Solution was prepared. After sufficiently stirring this solution, a liquid crystal aligning agent was prepared by filtering using a filter having a pore size of 1 μm.

<Manufacture and evaluation of liquid crystal cells>
Using the liquid crystal aligning agent prepared above, a liquid crystal cell was produced and evaluated as follows.
(1) Manufacture of liquid crystal cell for voltage holding ratio evaluation (anti-parallel alignment liquid crystal cell) The liquid crystal aligning agent prepared above is formed on a transparent conductive film made of an ITO film provided on one surface of a glass substrate having a thickness of 1 mm. Apply using a spinner, heat on a hot plate at 80 ° C. for 1 minute (pre-bake) to remove the solvent, and then heat on a hot plate at 230 ° C. for 15 minutes (post-bake) to coat with a film thickness of about 100 nm. A film was formed. The coating film is rubbed with a rubbing machine having a roll wrapped with a rayon cloth under the conditions of a roll rotation speed of 1,000 rpm, a stage moving speed of 2 cm / sec, and a hair foot indentation length of 0.4 mm. And a liquid crystal alignment film was formed by imparting liquid crystal alignment ability to the coating film. The substrate having the liquid crystal alignment film was subjected to ultrasonic cleaning for 1 minute in ultrapure water and then dried in a clean oven at 100 ° C. for 10 minutes.
By repeating these series of operations, two (a pair) substrates having a liquid crystal alignment film were prepared.
Next, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 3.5 μm is applied to each outer edge of the substrate having the pair of liquid crystal alignment films, and each liquid crystal alignment film surface is opposed to each other. The adhesive was cured by overlapping and pressing. Next, after filling a nematic liquid crystal (MLC-2019, manufactured by Merck & Co., Inc.) having a positive dielectric anisotropy between the liquid crystal injection port and the substrate, the liquid crystal injection port is filled with an acrylic photo-curing adhesive. By sealing, an anti-parallel alignment liquid crystal cell was manufactured.

(2) Evaluation of durability against thermal stress (thermal durability) The durability against thermal stress was evaluated using the voltage holding ratio as an index. First, after applying a voltage of 5 V at 60 ° C. with an application time of 60 microseconds and a span of 167 milliseconds to the anti-parallel alignment liquid crystal cell manufactured above, the voltage holding ratio after 167 milliseconds from the application release is obtained. Measured (initial voltage holding ratio (VHR0)). As a measuring device, VHR-1 manufactured by Toyo Corporation was used.
Next, after the liquid crystal cell after the initial voltage holding ratio measurement was left in a 100 ° C. oven for 1,000 hours to apply thermal stress, the voltage holding ratio was measured again in the same manner as described above (after applying the thermal stress). Voltage holding ratio (VHR1)).
Using these measured values, the following mathematical formula (1)
ΔVHR = VHR0−VHR1 (1)
When the difference in voltage holding ratio was found to be 5% or less, the thermal durability was evaluated as “good”, and when it exceeded 5%, the thermal durability was evaluated as “bad”. The orientation was “good”.

(3) Manufacture of afterimage characteristics evaluation liquid crystal cell (transverse electric field type liquid crystal cell) In the manufacture of the antiparallel alignment liquid crystal cell, a glass substrate and a transparent conductive film having two lines of comb-like transparent conductive film patterns made of chromium are used. Manufacturing of the anti-parallel alignment liquid crystal cell except that the liquid crystal alignment agent was applied to the transparent conductive film of the substrate having the comb-like transparent conductive film and one side of the other substrate, respectively, using a pair of glass substrates having no comb. A horizontal electric field type liquid crystal cell was manufactured in the same manner as described above. A schematic diagram showing the configuration of the comb-like transparent electrode pattern on the glass substrate is shown in FIG.
The two types of transparent conductive film patterns of the transverse electric field type liquid crystal cell manufactured above are hereinafter referred to as “electrode A” and “electrode B”, respectively.
(4) Evaluation of afterimage characteristics Evaluation of afterimage characteristics was performed according to the method described in Patent Document 7 (Japanese Patent Application Laid-Open No. 2003-214983).
The horizontal electric field type liquid crystal cell manufactured as described above is sandwiched between polarizing plates arranged in a cross Nicol, placed in an environment of 25 ° C. and 1 atm, no voltage is applied to the electrode B, and an AC voltage of 3.5 V is applied to the electrode A. And a composite voltage of DC voltage 5V was applied for 2 hours. Immediately thereafter, an AC voltage of 4 V was applied to both electrode A and electrode B. Here, a picture of the liquid crystal cell was taken every 5 seconds from the start of applying an AC voltage of 4 V to both electrodes, and the luminance of the electrodes A and B was measured. When the time until the difference in luminance between the electrodes A and B disappears is 500 seconds or less, the afterimage characteristic is evaluated as “good”, and when it exceeds 500 seconds, the afterimage characteristic is evaluated as “bad”. The afterimage characteristics of the liquid crystal cell were “good”.

Examples 2-5 and Comparative Examples 1-10
In Example 1 above, a liquid crystal aligning agent was prepared in the same manner as in Example 1 except that the type of polymer used and the solvent composition were as shown in Table 1, respectively. A display element was manufactured and evaluated.
The evaluation results are shown in Table 1.
In addition, the abbreviation of the solvent in Table 1 has the following meaning, respectively.
NMP: N-methyl-2-pyrrolidone BL: γ-butyrolactone BC: Butyl cellosolve

Claims (9)

At least one polymer selected from the group consisting of polyamic acid and polyimide, provided that at least a part of the polymer has the following formula (A)

The liquid crystal aligning agent characterized by including the structure represented by these.   The polymer is a polyamic acid obtained by reacting a tetracarboxylic dianhydride with a diamine containing a compound having the structure represented by the formula (A) and two amino groups, and dehydrating and ring-closing the polyamic acid. The liquid crystal aligning agent according to claim 1, which is at least one polymer selected from the group consisting of polyimides. Compounds having the structure represented by the above formula (A) and two amino groups are represented by the following formulas (A-1) to (A-3).

(In the above formulas (A-1) to (A-3), R ^I is an alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, respectively. A hydroxyl group, a carboxyl group, a cyano group or an acyl group, each of R ^II is a single bond or a divalent aromatic group having 4 to 20 carbon atoms, a is an integer of 0 to 3, and b is , 0 or 1 respectively.)
The liquid crystal aligning agent of Claim 2 which is a compound represented by either.   In addition to the structure represented by the above formula (A) and the compound having two amino groups, the diamine further includes p-phenylenediamine, 3,5-diaminobenzoic acid, 3,5-diaminobenzoic acid methyl ester, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 1,4-bis (4-aminophenyl) piperazine, 2,2'-dimethyl-4,4'-diaminobiphenyl and 4,4'-diamino The liquid crystal aligning agent of Claim 2 or 3 containing at least 1 sort (s) selected from the group which consists of -2,2'-bis (trifluoromethyl) biphenyl.   The tetracarboxylic dianhydride is 2,3,5-tricarboxycyclopentylacetic acid dianhydride, pyromellitic dianhydride, 2,3,2 ′, 3′-biphenyltetracarboxylic dianhydride, 2, 3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic 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 The liquid crystal aligning agent as described in any one of Claims 2-4 which contains at least 1 sort (s) selected from the group which consists of. The tetracarboxylic dianhydride is
2,3,5-tricarboxycyclopentyl acetic acid dianhydride;
Pyromellitic dianhydride, 2,3,2 ′, 3′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 3,4,3 ′, 4'-biphenyltetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro- The liquid crystal according to claim 5, comprising at least one selected from the group consisting of 2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione. Alignment agent.   The liquid crystal aligning agent as described in any one of Claims 1-6 used in order to form the liquid crystal aligning film of a horizontal electrolysis type liquid crystal display element.   A liquid crystal display element comprising a liquid crystal alignment film formed from the liquid crystal aligning agent according to claim 1.   A horizontal electrolysis type liquid crystal display element comprising a liquid crystal alignment film formed from the liquid crystal alignment agent according to claim 1.

Images