JP2009145453A - Liquid crystal aligning agent and liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal aligning agent for providing a liquid crystal alignment film having reduced residual DC voltage and superior charge voltage properties against leak. <P>SOLUTION: The liquid crystal aligning agent includes at least one kind of polymer selected from a group consisting of a polyamic acid obtained by the reaction between tetracarboxylic acid dianhydride and a diamine including a compound represented by formula (1) (where R is a hydrogen atom or a monovalent organic group) and polyimide obtained by dehydration ring closure of the polyamic acid. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal aligning agent and a liquid crystal display element. More specifically, the present invention relates to a liquid crystal aligning agent that provides a liquid crystal alignment film having excellent electrical characteristics and heat resistance, and a liquid crystal display element capable of high-quality display, capable of suppressing display deterioration due to thermal stress, and capable of being driven for a long time. .

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 a liquid crystal display element having a liquid crystal alignment film made of these resin materials, a high level of characteristics is required for the liquid crystal alignment film in order to realize high-quality video expression that users in recent years demand for the liquid crystal display element. In particular, the demand for image sticking characteristics in a low voltage drive type liquid crystal display element aiming at low power consumption has become severe, and the performance of the liquid crystal alignment film used in the conventional liquid crystal display element is low voltage drive type. It has been insufficient as a liquid crystal alignment film for liquid crystal display elements. That is, when a conventionally known liquid crystal alignment film is applied as it is to a low-voltage drive type liquid crystal display element, there are many cases where there is a problem in image sticking characteristics. Therefore, there is a demand for a liquid crystal alignment film that has good image sticking characteristics, that is, a lower residual DC voltage.
In recent years, with the increase in size of substrates, the manufacturing process of liquid crystal display elements has made great progress. In particular, technologies such as a large substrate transfer technology and a liquid crystal dropping method (ODF) are attracting attention, and are considered to become main technologies in the future. In these processes, the substrate is fixed using a so-called “electrostatic chuck” method that uses strong static electricity. However, this static electricity accumulates on the substrate and remains without being neutralized, causing display defects. There is a problem of becoming. In order to solve this problem, the introduction of a static eliminator is the most effective. However, because it requires enormous costs, the liquid crystal alignment film that covers the substrate surface can reduce display defects caused by static electricity. It has been demanded. That is, there is a demand for a liquid crystal alignment film with improved voltage leakage.
However, a liquid crystal aligning agent that provides a liquid crystal aligning film that satisfies the above requirements is not yet known.
JP-A-9-197411 JP 2003-149648 A JP 2003-107486 A 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 of the present invention is to provide a liquid crystal aligning agent that provides a liquid crystal aligning film with reduced residual DC voltage and excellent voltage leakage.
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 another object of the present invention is to provide a polymer that provides a liquid crystal aligning agent having the above-mentioned advantages and a compound that is a raw material thereof.
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 (1)

(In formula (1), R is a hydrogen atom or a monovalent organic group.)
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
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.
Thirdly, the above object of the present invention is as follows.
This is achieved by a polyamic acid obtained by reacting a tetracarboxylic dianhydride and a diamine containing the compound represented by the above formula (1) or a polyimide obtained by dehydrating and ring-closing the polyamic acid.
Fourthly, the object of the present invention is as follows.
This is achieved by the compound represented by the above formula (1).

The liquid crystal aligning agent of the present invention can form a liquid crystal aligning film that is excellent in electrical characteristics and that does not deteriorate the liquid crystal aligning ability 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 (1), and a polyimide obtained by dehydrating and ring-closing the polyamic acid. At least one polymer selected from the group consisting of:
<Polyamic acid>
The polyamic acid that can be 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 (1).

[Tetracarboxylic dianhydride]
The tetracarboxylic dianhydride used for synthesizing the polyamic acid contained in the liquid crystal aligning agent of the present invention includes alicyclic tetracarboxylic dianhydride, aliphatic tetracarboxylic dianhydride and aromatic tetra Carboxylic dianhydrides can be mentioned.
Specific examples of the alicyclic tetracarboxylic dianhydride include, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic. Acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1 , 2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5 -Cyclohexanetetracarboxylic dianhydride, 3,3 ', 4,4'-dicyclohexyltetracarboxylic dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6 -Tetracarboxylic Dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 1,3,3a, 4 , 5,9b-Hexahydro-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b -Hexahydro-5-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione,

1,3,3a, 4,5,9b-hexahydro-5-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-7-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-7-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-ethyl-5 ( Trahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5,8-dimethyl- 5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 5- (2,5-dioxotetrahydrofural) -3-methyl-3 -Cyclohexene-1,2-dicarboxylic dianhydride, bicyclo [2.2.2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 3-oxabicyclo [3. 2.1] Octane-2,4-dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′-dione), the following formula (TI) or (T-II)

(Wherein R ¹ and R ³ are divalent organic groups having an aromatic ring, R ² and R ⁴ are hydrogen atoms or alkyl groups, and a plurality of R ² and R ⁴ are the same, May be different.)
The compound etc. which are represented by these can be mentioned.
Specific examples of the aliphatic tetracarboxylic dianhydride include butanetetracarboxylic dianhydride.
Specific examples of the aromatic tetracarboxylic dianhydride include, for example, 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'-dimethyldiphenylsilane tetracarboxylic dianhydride, 3,3 ', 4,4'-tetraphenylsilane tetracarboxylic dianhydride 1,2,3,4-furantetracarboxylic dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4′-bis (3,4-di Carboxyphenoxy Diphenylsulfone dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidenediphthalic dianhydride, 3, 3 ′, 4,4′-biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis (tri Phenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4'-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4'-diphenylmethane dianhydride, ethylene glycol-bis (an Hydrotrimellitate), propylene glycol-bis (anhydrotrimellitate), 1,4-butanediol-bis (anhydro) Remellitate), 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)

And the like, and the like.
These tetracarboxylic dianhydrides can be used singly 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 selected from the group consisting of alicyclic tetracarboxylic dianhydride and pyromellitic dianhydride. It is preferable that it contains at least one, among which 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxy Cyclopentyl acetic acid dianhydride, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 5 (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5 , 6-tetracarboxylic dianhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-dianhydride, 1,3,3a, 4,5,9b-hexahydro- 5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl- 5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5,8- Dimethyl-5- (tetrahydro-2,5-dioxy -3-furanyl) -naphtho [1,2-c] furan-1,3-dione, bicyclo [2.2.2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride Product, 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3 '-(tetrahydrofuran-2', 5'-dione), represented by the above formula (TI) Among the compounds, the following formulas (T-5) to (T-7)

Of the compounds represented by formula (T-II), the following formula (T-8)

And a tetracarboxylic dianhydride containing at least one selected from the group consisting of the compound represented by formula (1) and pyromellitic dianhydride is more preferable from the viewpoint of achieving good liquid crystal alignment.
The tetracarboxylic dianhydride used for synthesizing the polyamic acid contained in the liquid crystal aligning agent of the present invention is selected from the group consisting of alicyclic tetracarboxylic dianhydride and pyromellitic dianhydride. It is preferable that 50 mol% or more is included with respect to all tetracarboxylic dianhydrides, and more preferable that 80 mol% or more is included. Further, at least one selected from alicyclic tetracarboxylic dianhydrides is preferably contained in an amount of 50 mol% or more, particularly preferably 80 mol% or more, based on the total tetracarboxylic dianhydrides.

[Diamine]
The diamine used for synthesizing the polyamic acid contained in the liquid crystal aligning agent of the present invention includes a compound represented by the above formula (1). Examples of the monovalent organic group represented by R in the above formula (1) include an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, and an alicyclic group having 3 to 40 carbon atoms. Can do.
Examples of the alkyl group having 1 to 40 carbon atoms include the following formula (R-1):
_{- (CH 2) a -CH 3} (R-1)
(In formula (R-1), a is an integer of 1 to 19, preferably an integer of 11 to 17.)
The alkyl group represented by these can be mentioned. Examples of the fluoroalkyl group having 1 to 40 carbon atoms include the following formula (R-2) or (R-3)
_{- (CH 2) b -CF 3} (R-2)
_{- (CH 2) c -C 2} F 5 (R-3)
(B in the formula (R-2) and c in the (R-3) are each independently an integer of 1 to 19, preferably an integer of 3 to 9.)
The fluoroalkyl group represented by these can be mentioned. The alicyclic group having 3 to 40 carbon atoms is preferably an alicyclic group having 17 to 40 carbon atoms having a steroid skeleton, particularly preferably a 3-cholestanyl group or a 3-cholestenyl group.
In the above formula (1), the bonding positions of the two amino groups bonded to the two phenyl groups are preferably in the meta positions from the viewpoints of solubility and polymerizability.
Examples of the compound represented by the formula (1) preferably used in the present invention include the following formulas (1-1) to (1-6).

(Wherein a, b and c have the same meanings as in formulas (R-1), (R-2) and (R-3), respectively).
The compound represented by either of these can be mentioned.
The compound represented by the above formula (1) can be synthesized according to a conventional method of organic chemistry.
For example, in the above formula (1), a compound in which R is a hydrogen atom is reacted with 2 equivalents of nitrophenyl cyanate isocyanate and 1 equivalent of an alkali metal salt of cyanate to produce an intermediate 1,3-bis (nitrophenyl). ) -S-triazine-2,4,6-trione can be synthesized, and then the nitro group of the intermediate can be reduced.
In addition, the compound in which R is a monovalent organic group in the above formula (1) includes 1,3-bis (nitrophenyl) -s-triazine-2,4,6-trione synthesized in the same manner as described above, Compound R—X (where R is the same monovalent organic group as in formula (1) above, X is a chlorine atom, bromine atom or iodine atom) or R—OH (where R is the above formula) The same monovalent organic group as in (1)), and the 5-position substituted 1,3-bis (nitrophenyl) in which the 5-position of the s-triazine ring is substituted with a monovalent organic group. It can be synthesized by obtaining -s-triazine-2,4,6-trione as an intermediate and then reducing the nitro group of the intermediate.
The reduction reaction of the nitro group can be carried out by an appropriate method such as a known reduction reaction, for example, a method using palladium carbon and hydrazine monohydrate, a method using zinc and ammonium chloride, and a method using tin chloride.

As a diamine for synthesizing a polyamic acid, only the compound represented by the above formula (1) may be used alone, or a compound represented by the above formula (1) and another diamine may be used in combination. Also good.
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′-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 ' 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-hydroanthracene, 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] hexafluoro Propane, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 4,4′-bis [(4-amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl, di (4 -Aromatic diamines such as aminophenyl) benzidine;

1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1 , 4-diaminocyclohexane, isophorone diamine, tetrahydrodicyclopentadienylenediamine, tricyclo [6.2.1.0 ^2,7 ] -undecylene diamine, 4,4′-methylenebis (cyclohexylamine), 1,3 -Aliphatic or cycloaliphatic diamines such as 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, 1- (3,5-diaminophenyl) -3-decylsuccinimide, 1- (3 5-Diaminophenyl) -3-octadecylsuccinimide, 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 divalent. 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 skeleton or a group selected from the group consisting of a steroid skeleton, a trifluoromethyl group and a fluoro group, or an alkyl group having 6 to 30 carbon atoms.)
A mono-substituted phenylenediamine represented by:
The following formula (D-IV)

(In Formula (D-IV), 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, and p is an integer of 1 to 3) And q is an integer from 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.
Among these, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 4,4′-diaminodiphenyl ether, 2, 2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2 , 2-bis (4-aminophenyl) hexafluoropropane, 4,4 ′-(p-phenylenediisopropylidene) bisaniline, 4,4 ′-(m-phenylenediisopropylidene) bisaniline, 1,4-cyclohexanediamine 4,4′-methylenebis (cyclohexylamine), 1,4-bis (4-amino) Enoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, compounds represented by the above formulas (D-1) to (D-5), 2,6-diaminopyridine, 3,4- Of the compounds represented by diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, and the above formula (DI), the following formula (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- 2,5-diaminobenzene, dodecanoxy-2,5-diaminobenzene, pentadecanoxy-2,5-diaminobenzene, hexadecanoxy-2,5-diaminobenzene, octadecanoxy-2,5-diaminobenzene, the following formula (D-8) ~ (D-16)

The compounds represented by each of these are preferred.
The diamine used for synthesizing the polyamic acid contained in the liquid crystal aligning agent of the present invention preferably contains 1 mol% or more of the compound represented by the above formula (1) with respect to the total diamine. More preferably, it contains 50 mol%. Moreover, it is preferable that the diamine used for this invention contains at least 1 type selected from the compound represented by the said Formula (D-III) other than the compound represented by the said Formula (1). In this case, the compound represented by the formula (D-III) is more preferably contained in an amount of 0.5 mol% or more, more preferably 1 mol% or more, based on the total diamine.

[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 −20 ° C. to 150 ° C., more preferably at 0 to 100 ° C., preferably 1 to 48 hours, more preferably 2 to 12 hours. Done. Here, the organic solvent is not particularly limited as long as it can dissolve the produced polyamic acid. For example, 1-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, 3-butoxy Amide compounds such as -N, N-dimethylpropanamide, 3-methoxy-N, N-dimethylpropanamide, 3-hexyloxy-N, N-dimethylpropanamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexa Examples include aprotic compounds such as methyl phosphortriamide; phenolic compounds such as m-cresol, xylenol, phenol, and halogenated phenol. The amount of organic solvent used (α) is usually such that the total amount (β) of tetracarboxylic dianhydride and diamine compound is 0.1 to 30% by weight based on the total amount of the reaction solution (α + β). It is preferable that

As the organic solvent, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, and the like, which are poor solvents for polyamic acid, may be used in combination as long as the generated polyamic acid does not precipitate. Specific examples of such poor solvents include, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol. , Ethylene glycol monomethyl ether, ethyl lactate, butyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, malon Acid diethyl, diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i Propyl ether, ethylene glycol-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene, diisobutyl ketone, isoamylpropionate, isoamylisobutyrate , And the like di-iso-pentyl ether.
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 80% by weight or less based on the total amount of the solvent. 50% by weight or less is more preferable.

  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. 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>
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 a tetracarboxylic dianhydride containing at least one selected from alicyclic tetracarboxylic dianhydrides. 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-carboxynorbornane-2: 3,5: 6- A tetracarboxylic acid dihydrate containing at least one selected from the group consisting of dianhydride and 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone More preferably, it is an anhydride.
The tetracarboxylic dianhydride used for synthesizing the polyimide contained in the liquid crystal aligning agent of the present invention is at least one selected from alicyclic tetracarboxylic dianhydrides to all tetracarboxylic dianhydrides. It is preferable that 50 mol% or more is contained.
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.

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 80 mol% or more, more preferably 85 mol% 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 to 120 hours, more preferably 2 to 48 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 to 24 hours, more preferably 2 to 8 hours.

  In the method (ii), a reaction solution containing polyimide is obtained as described above. This reaction solution may be used as it is for the preparation of a liquid crystal aligning agent, or may be used for the preparation of a 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, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine, etc. it can. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.
The use ratio of the molecular weight regulator is preferably 20 parts by weight or less, more preferably 5 parts by weight or less, with respect to 100 parts by weight of the diamine.

-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 polymer is a value measured at 25 ° C. using an E-type rotational viscometer for a polymer solution having a concentration of 10% by weight prepared using a good solvent for the polymer. .

<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 and adhesion improvers.
These other polymers can be used to improve solution and electrical properties. Such other polymers include polyamic acid obtained by reacting tetracarboxylic dianhydride and a diamine containing the compound represented by the above formula (1), and a polymer other than polyimide formed by dehydrating and ring-closing the polyamic acid. A polyamic acid obtained by reacting, for example, a tetracarboxylic dianhydride and a diamine not containing the compound represented by the above formula (1) (hereinafter referred to as “other polyamic acid”), the polyamic 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.
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 (1) 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 99% by weight or less, more preferably 90% by weight or less.

The said adhesive improvement agent can be used in order to improve the adhesiveness with respect to the substrate surface of the liquid crystal aligning film obtained. 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.
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, 3- (N-allyl--N- glycidyl) aminopropyltrimethoxysilane, 3- (N, N- diglycidyl) and the like aminopropyltrimethoxysilane.
The use ratio of the epoxy compound as described above 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 proportion of the functional silane compound as described above is preferably 40 parts by weight or less with respect to 100 parts by weight of the total amount of the polymer.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of the present invention preferably contains at least one selected from the group consisting of polyamic acid and polyimide as described above and other additives optionally blended as necessary, preferably dissolved in an organic solvent. Configured.
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 time is preferably 0.1 to 10 minutes, more preferably 1 to 5 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 5 to 300 minutes, more preferably 30 to 120 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. In the case of a VA liquid crystal display element, the rubbing process may not be performed.
Further, for example, Patent Document 4 (Japanese Patent Laid-Open No. 6-222366) and Patent Document 5 (Japanese Patent Laid-Open No. 6-281937) show liquid crystal alignment films formed with 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 (1)>
Example 1 (Synthesis of Compound (1-2-1))
Scheme 1 below

The compound (1-2-1) was synthesized according to
38 g of potassium cyanate was charged into a 2 L three-necked flask equipped with a nitrogen introduction tube, a thermometer and a dropping funnel, and 224 g of 3-nitrophenyl isocyanate was added to the dropping funnel, followed by sufficient drying. Next, 1 L of sufficiently dried N, N-dimethylformamide was added to the flask and 500 mL to the dropping funnel, respectively, and the flask was heated to 75 ° C., and then dropped, and the reaction was continued with stirring for 30 minutes. . After completion of the reaction, N, N-dimethylformamide was removed under reduced pressure, and 1 L of ethyl acetate and 3 L of water were added to the residue to separate the layers. Concentrated hydrochloric acid was added to the aqueous layer, and the deposited precipitate was collected and recrystallized with ethanol to obtain 191 g of white crystals of the compound (1-1a).
Next, 74 g of the compound (1-1a) obtained above was charged in a 2,000 mL three-necked flask, and further 2.2 g of potassium hydroxide, 73 g of n-octadecyl bromide and 1,000 mL of N, N-dimethylformamide. And the reaction was conducted at 50 ° C. with stirring for 5 hours. After completion of the reaction, ethyl acetate and saturated aqueous sodium hydrogen carbonate solution were added to the reaction mixture and shaken to remove the aqueous layer. The organic layer was washed with water, dried over magnesium sulfate, concentrated, and recrystallized with a mixed solvent of ethanol and tetrahydrofuran to obtain 41 g of yellow crystals of compound (1-2-1b).
Next, 23.9 g of the compound (1-2-1b) obtained above was charged into a 1,000 mL three-necked flask equipped with a thermometer, and 86 g of tin chloride dihydrate and 400 mL of ethanol were further added. The reaction was carried out at 70 ° C. with stirring for 1 hour. After completion of the reaction, the reaction mixture was neutralized by adding an aqueous sodium hydrogen carbonate solution, and further filtered by adding ethyl acetate, and then the organic layer was washed with water, dried over magnesium sulfate, concentrated, and then silica column. And 5.1 g of white crystals of compound (1-2-1) were obtained by recrystallization from ethanol.

<Polyimide synthesis example>
Example 2
2.24 g (0.01 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic acid anhydride and 0.97 g (0.009 mol) of p-phenylenediamine as a diamine compound and the above Example 1 0.56 g (0.001 mol) of the compound (1-2-1) obtained in 1 above was dissolved in 15.12 g of N-methyl-2-pyrrolidone, and reacted at 60 ° C. for 6 hours. A solution containing% by weight was obtained. The solution viscosity of this polyamic acid solution was 5,000 mPa · s.
Next, 35.10 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 0.79 g of pyridine and 1.02 g of acetic anhydride were added, and dehydration ring closure was performed at 110 ° C. for 4 hours. After the dehydration cyclization reaction, the solvent in the system was replaced with new N-methyl-2-pyrrolidone (pyridine and acetic anhydride used for the dehydration cyclization reaction were removed from the system in this operation), thereby imido. 19.00 g of a solution containing 19% by weight of polyimide (A-1) having a conversion rate of about 49% was obtained. A small amount of this solution was taken, N-methyl-2-pyrrolidone was added, and the solution viscosity measured as a solution having a polymer concentration of 6.0% by weight was 22 mPa · s.
Comparative Synthesis Example 1
224 g (1.0 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic acid anhydride and 99 g (0.90 mol) of p-phenylenediamine as a diamine compound and the above formula (D-10) 53 g (0.10 mol) of the represented compound was dissolved in 1,510 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours to obtain a polymer solution containing 20% by weight of polyamic acid. The solution viscosity of this polyamic acid solution was 2,560 mPa · s.
Next, 3,500 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 79 g of pyridine and 102 g of acetic anhydride were added, and dehydration ring closure was performed at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with new N-methyl-2-pyrrolidone (pyridine and acetic anhydride used in the dehydration ring closure reaction were removed from the system by this operation), thereby imido. About 2,000 g of a solution containing 20% by weight of polyimide (B-1) having a conversion rate of about 53% was obtained. A small amount of this solution was taken, N-methyl-2-pyrrolidone was added, and the solution viscosity measured as a solution having a polymer concentration of 6.0% by weight was 16 mPa · s.

<Preparation and evaluation of liquid crystal aligning agent>
Example 3
(I) Preparation of liquid crystal aligning agent N-methyl-2-pyrrolidone and butyl cellosolve were added to a solution containing the polyimide (A-1) synthesized in Example 1 as a polymer, and the solvent composition was N-methyl-2- A liquid crystal aligning agent was prepared by making a pyrrolidone: butyl cellosolve = 50: 50 (weight ratio) and a solid content concentration of 4% by weight and filtering this solution using a filter having a pore size of 1 μm.
(II) Evaluation of liquid crystal aligning agent (1) Manufacture of liquid crystal display element The liquid crystal aligning agent prepared above was applied with a spinner on a transparent conductive film made of an ITO film provided on one side of a glass substrate having a thickness of 1 mm. The film was heated at 200 ° C. for 60 minutes to form a coating film (liquid crystal alignment film) having a thickness of 0.08 μm. This operation was repeated to prepare a pair (two) of substrates having a liquid crystal alignment film on the transparent conductive film.
After applying an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm to the outer edges of the surfaces having the liquid crystal alignment film of the pair of substrates, the liquid crystal alignment film surfaces are stacked and pressure-bonded so as to face each other. The adhesive was cured. Next, a negative type liquid crystal (MLC-6608, manufactured by Merck & Co., Inc.) is filled between the substrates through the liquid crystal injection port, and then the liquid crystal injection port is sealed with an acrylic photo-curing adhesive, and polarized on both sides outside the substrate. A liquid crystal display element was manufactured by laminating the plates.
This liquid crystal display element was evaluated for vertical alignment, residual DC voltage, and voltage leakage by the following methods.

(2) Evaluation of vertical alignment For the liquid crystal display device manufactured above, the presence or absence of anomalous domains when the voltage was turned on / off under crossed Nicols was observed using a polarizing microscope. The quality was evaluated as “good”.
(3) Evaluation of residual DC voltage After applying the direct current voltage 5.0V to the liquid crystal display element manufactured above for 20 hours at an environmental temperature of 60 ° C. and allowing to cool at room temperature for 15 minutes immediately after turning off the direct current voltage, The voltage remaining in the liquid crystal cell was determined by a flicker-erasing method. At this time, the case where the residual voltage was 300 mV or less was evaluated as the residual DC voltage “good”.
(4) Evaluation of voltage leakage characteristics After applying a voltage of 10 V for 1 second to the liquid crystal display element manufactured as described above, the circuit was opened and left standing, and the temporal change in transmitted light intensity transmitted from the liquid crystal cell was measured. It was measured. At this time, a voltage drop that was reduced to 10% of the initial transmitted light intensity within 10 minutes (when voltage was applied) was evaluated as “good”, and a voltage that did not decrease within 10 minutes was evaluated as “bad”.
All the above evaluation results are shown in Table 1. It was confirmed that the liquid crystal aligning agent of this example showed good vertical alignment and low residual DC voltage, and good voltage leakage.

Example 4
(I) Preparation of liquid crystal aligning agent N-methyl-2-pyrrolidone and butyl cellosolve are added to a solution containing the polyimide (A-1) synthesized in Example 1 as a polymer, and N, N, N ′ as an epoxy compound. , N′-tetraglycidyl-m-xylylenediamine is added in an amount of 10 parts by weight based on 100 parts by weight of polyimide (A-1), and the solvent composition is N-methyl-2-pyrrolidone: butyl cellosolve = 50: 50 (weight) The liquid crystal aligning agent was prepared by preparing a solution having a solid content concentration of 4% by weight and filtering the solution using a filter having a pore size of 1 μm.
(II) Evaluation of liquid crystal aligning agent A liquid crystal display element was produced and evaluated in the same manner as in Example 3 except that the liquid crystal aligning agent prepared above was used as the liquid crystal aligning agent.
The evaluation results are shown in Table 1.
Comparative Example 1
A liquid crystal aligning agent was prepared and evaluated in the same manner as in Example 3 except that the solution containing the polyimide (B-1) obtained in Comparative Synthesis Example 1 was used as the polymer solution.
The evaluation results are shown in Table 1.
Comparative Example 2
A liquid crystal aligning agent was prepared and evaluated in the same manner as in Example 4 except that the solution containing the polyimide (B-1) obtained in Comparative Synthesis Example 1 was used as the polymer solution.
The evaluation results are shown in Table 1.

Claims (8)

Tetracarboxylic dianhydride and the following formula (1)

(In formula (1), R is a hydrogen atom or a monovalent organic group.)
Characterized in that it contains at least one polymer selected from the group consisting of a polyamic acid obtained by reacting with a diamine containing a compound represented by: and a polyimide formed by dehydrating and ring-closing the polyamic acid, Liquid crystal aligning agent.   The R in the formula (1) is a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, or an alicyclic group having 3 to 40 carbon atoms. Liquid crystal aligning agent.   The liquid crystal aligning agent of Claim 2 whose R in the said Formula (1) is a C17-C40 alicyclic group which has a steroid skeleton.   The tetracarboxylic dianhydride includes at least one selected from the group consisting of alicyclic tetracarboxylic dianhydride and pyromellitic dianhydride, according to any one of claims 1 to 3. Liquid crystal aligning agent.   The liquid crystal display element which comprises the liquid crystal aligning film formed from the liquid crystal aligning agent as described in any one of Claims 1-4.   A polyamic acid obtained by reacting a tetracarboxylic dianhydride and a diamine containing a compound represented by the above formula (1).   A polyimide obtained by dehydrating and ring-closing a polyamic acid obtained by reacting a tetracarboxylic dianhydride with a diamine containing a compound represented by the above formula (1).   A compound represented by the above formula (1).