JP5158356B2 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element.

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 nematic) in which the long axis of liquid crystal molecules is continuously twisted by 90 ° from one substrate to the other substrate. ) TN type liquid crystal display element having a liquid crystal cell, STN (Super Twisted Nematic) type liquid crystal display element capable of realizing a higher contrast ratio than TN type liquid crystal display element, IPS (In-Plane Switching) type having less viewing angle dependency Optical compensation bend (Optical) with low viewing angle dependency and excellent high-speed response of video screen y Compensated Birefringence = OCB) type liquid crystal display device, such as a VA (Vertical Alignment) type liquid crystal display device using a nematic liquid crystal is known to have a negative dielectric anisotropy (Patent Documents 1 to 6).
Known materials for the liquid crystal alignment film in these liquid crystal display elements include polyimide, polyamide, and polyester. Among these, polyimide is excellent in various properties such as heat resistance, affinity with liquid crystal, and mechanical strength, and is used in many liquid crystal display elements (Non-Patent Documents 1 and 2).

By the way, in the liquid crystal display element, the request | requirement of the display quality improvement, such as high definition, has become severe. In recent years, with the spread of large-sized liquid crystal televisions and the development of moving image fixing technology, the ability to display high-level moving images quickly and finely in liquid crystal display elements has been increasingly required. . From this point of view, the liquid crystal alignment film is required to have high voltage holding performance and good image sticking characteristics. Here, burn-in refers to a phenomenon in which an image displayed on a screen by applying a charge remains even after the release of charge, the degree of image remaining immediately after release of charge stress (burn-in characteristics immediately after releasing stress), and charge stress. It is expressed by both the length of time required from the cancellation to the disappearance of the image (burn-in relaxation property). That is, if the burn-in immediately after the stress release is large, the burn-in characteristic is poor only. If the burn-in immediately after the stress release is small, but the burn-in characteristic does not disappear for a long time (for example, several days), the burn-in characteristic is also poor.
In addition to various performances that have been conventionally required as a liquid crystal alignment film, that is, heat resistance, affinity with liquid crystal, mechanical strength, etc., it has high voltage holding performance, and also has burn-in and burn-in immediately after stress release A liquid crystal alignment film material excellent in all of relaxation properties has not been known so far.
JP 2002-62537 A Japanese Patent Laid-Open No. 7-261181 JP 2003-107486 A Japanese Patent Laid-Open No. 11-258605 JP 2007-9031 A JP-A-4-153622 JP 2002-327058 A JP-A-6-222366 JP-A-6-281937 JP-A-5-107544 Electronic material (12), p52 (1988) Display and Imaging, Volume 4, p213 (1996)

The present invention has been made in view of the above circumstances, and the object thereof is to provide various performances as a liquid crystal alignment film, while further maintaining high voltage holding performance, seizure immediately after stress release, and seizure mitigation properties. It is an object of the present invention to provide a liquid crystal alignment film excellent in the quality, a liquid crystal alignment agent that provides the same, and a liquid crystal display element excellent in display quality capable of displaying high-quality moving images quickly and finely.
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:
(A) tetracarboxylic dianhydride including 1,2,3,4-cyclobutanetetracarboxylic dianhydride, and the following formula (1)

(In Formula (1), R ^I and R ^II are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
And (B) a polyamic acid obtained by reacting a diamine containing a compound represented by formula (B), and an imidized polymer of polyamic acid obtained by reacting a tetracarboxylic dianhydride and a diamine, and ( The ratio of the number of imide rings of (B) imidized polymer to the total of A) the number of amic acid structures possessed by polyamic acid and (B) the number of imide rings possessed by imidized polymer and the number of amic acid structures Achieved by a liquid crystal aligning agent that is 10-50%, secondly achieved by a liquid crystal aligning film formed from the above liquid crystal aligning agent, and thirdly,
This is achieved by a liquid crystal display element comprising the above liquid crystal alignment film.

The liquid crystal alignment film formed from the liquid crystal alignment agent in the present invention has various performances as a liquid crystal alignment film, and is excellent in high voltage holding performance, burn-in immediately after stress release, and burn-in relaxation. The liquid crystal aligning agent of this invention can be used suitably for various liquid crystal display elements, such as TN type, STN type, VA type, IPS type, OCB type, ferroelectricity, and antiferroelectricity.
The liquid crystal display element of the present invention comprising a liquid crystal alignment film formed from the liquid crystal aligning agent of the present invention can display high-quality moving images quickly and finely and has excellent display quality. The liquid crystal display element of the present invention can be suitably used for various devices, and can be used for display devices such as desk calculators, watches, table clocks, counting display boards, word processors, personal computers, and liquid crystal televisions.

The liquid crystal aligning agent of the present invention is
(A) A polyamic acid obtained by reacting a tetracarboxylic dianhydride containing 1,2,3,4-cyclobutanetetracarboxylic dianhydride with a diamine containing a compound represented by the above formula (1) And (B) an imidized polymer of polyamic acid obtained by reacting tetracarboxylic dianhydride and diamine.
<(A) Polyamic acid>
[Tetracarboxylic dianhydride]
(A) As a tetracarboxylic dianhydride for synthesizing a polyamic acid, only 1,2,3,4-cyclobutanetetracarboxylic dianhydride may be used, and 1,2,3,4-cyclobutane. Tetracarboxylic dianhydride and other tetracarboxylic dianhydrides may be used in combination. Examples of other tetracarboxylic dianhydrides that can be used here include butanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4- Tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride 3,3 ′, 4,4′-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6-tricarboxynorbornane- - acetic dianhydride, 2,3,4,5-tetrahydrofuran tetracarboxylic 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, , 3,3a, 4,5,9b-Hexahydro-7-ethyl-5- (teto Hydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5 (Tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-ethyl-5 -(Tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5,8- Dimethyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 5- (2,5-dioxotetrahydrofuranyl) -3- Methyl-3-cyclohexene-1,2-dicarboxylic anhydride, bi Chlo [2.2.2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 3-oxabicyclo [3.2.1] octane-2,4-dione-6 -Spiro-3 '-(tetrahydrofuran-2', 5'-dione), 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride 3,5,6-tricarboxy-2-carboxynorbornane-2: 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^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 each represent a divalent organic group having an aromatic ring, and R ² and R ⁴ each represent a hydrogen atom or an alkyl group. And a plurality of R ² and R ⁴ may be the same or different.)
An aliphatic or alicyclic tetracarboxylic dianhydride such as a compound represented by each of the following:
Pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 1,4,5, 8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic dianhydride, 3,3 ′, 4,4′-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ′, 4,4′-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4,4′-bis ( 3,4-dicar Boxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidene diphthalic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2 , 2 ′, 3,3′-biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis ( Triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4′-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4′-diphenylmethane dianhydride, ethylene glycol-bis ( Anhydrotrimellitate), propylene glycol-bis (anhydrotrimellitate), 1,4-butanediol-bis (anhydrotrimellitate) Retate), 1,6-hexanediol-bis (anhydrotrimellitate), 1,8-octanediol-bis (anhydrotrimellitate), 2,2-bis (4-hydroxyphenyl) propane-bis ( Anhydrotrimellitate), the following formulas (T-1) to (T-4)

An aromatic tetracarboxylic dianhydride such as a compound represented by each of the above can be exemplified. These may be used alone or in combination of two or more.
(A) Other tetracarboxylic dianhydrides that can be used to synthesize polyamic acid include butanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4 among the above. -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, 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-carboxynorbornane-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'-Benzophenonetetracarboxylic dianhydride 3,3 ′, 4,4′-biphenylsulfonetetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid Of the compounds represented by the dianhydride and the above formula (TI), the following formulas (T-5) to (T-7)

And the following formula (T-8) among the compounds represented by formula (T-II):

It is preferable to use at least one selected from the group consisting of the compounds represented by the above from the viewpoint that the formed liquid crystal alignment film can exhibit better liquid crystal alignment.
Other particularly preferred tetracarboxylic dianhydrides are 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-tri Carboxy-2-carboxynorvo Nan -2: 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^{2, 6]} undecane -3,5,8,10- tetraone, pyromellitic It is at least one selected from the group consisting of an anhydride and a compound represented by the above formula (T-5).
(A) The tetracarboxylic dianhydride used for synthesizing the polyamic acid is 40 moles of 1,2,3,4-cyclobutanetetracarboxylic dianhydride with respect to the total tetracarboxylic dianhydride. %, Preferably 50 mol% or more, more preferably 80 mol% or more.

[Diamine]
(A) The diamine used for synthesizing the polyamic acid contains a compound represented by the above formula (1).
Examples of the alkyl group having 1 to 4 carbon atoms of R ^I and R ^II in the above formula (1) include a methyl group, an ethyl group, and a propyl group. R ^I and R ^II are each preferably a hydrogen atom or a methyl group. When R ^I and R ^II are alkyl groups having 1 to 4 carbon atoms, the bonding position is preferably a meta position with respect to the amide bond.
In the above formula (1), the bonding positions of the two amino groups bonded to the benzene ring are preferably para positions with respect to the amide bond.
Preferable specific examples of the compound represented by the above formula (1) include, for example, the following formulas (1-1) to (1-3):

The compound etc. which are represented by these can be mentioned.
(A) As a diamine for synthesizing a polyamic acid, only the compound represented by the above formula (1) may be used, and the 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 here include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, 4,4′-diaminodiphenyl sulfide, 4 , 4'-diaminodiphenylsulfone, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 2,2'-dimethyl-4,4'- Diaminobiphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl, 2,2′-ditrifluoromethyl-4,4′-diaminobiphenyl, 3,3′-ditrifluoromethyl-4,4′-diamino Biphenyl, 5-amino-1- (4′-aminophenyl) -1,3,3-trimethylindane, 6-amino-1- (4′- Minophenyl) -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, 4,4'-bis (4-aminophenoxy) biphenyl, 1,3-bis (4- Aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -1 -Hydroanthracene, 2,7-diaminofluorene, 9,9-dimethyl-2,7-diaminofluorene, 9,9-bis (4-aminophenyl) fluorene, 4,4'-methylene-bis (2-chloroaniline) ), 2,2 ′, 5,5′-tetrachloro-4,4′-diaminobiphenyl, 2,2′-dichloro-4,4′-diamino-5,5′-dimethoxybiphenyl, 3,3′- Dimethoxy-4,4′-diaminobiphenyl, 1,4,4 ′-(p-phenyleneisopropylidene) bisaniline, 4,4 ′-(m-phenyleneisopropylidene) bisaniline, 2,2′-bis [4- ( 4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 4,4′-bis [( - Amino-2-trifluoromethyl) phenoxy] - aromatic diamines such as octafluoro biphenyl;

1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1 , 4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindanylene methylenediamine, tricyclo [6.2.1.0 ^2,7 ] -undecylenedimethyldiamine, 4 Aliphatic or cycloaliphatic diamines such as 1,4′-methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane;
2,3-diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 5,6-diamino-2,3-dicyanopyrazine, 5,6-diamino-2,4 -Dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 1,4-bis (3-aminopropyl) piperazine, 2,4-diamino-6-isopropoxy-1,3 , 5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine, 2,4-diamino-6-methyl -S-triazine, 2,4-diamino-1,3,5-triazine, 4,6-diamino-2-vinyl-s-triazine, 2,4-diamino-5-phenylthiazole, 2,6- Aminopurine, 5,6-diamino-1,3-dimethyluracil, 3,5-diamino-1,2,4-triazole, 6,9-diamino-2-ethoxyacridine lactate, 3,8-diamino-6 Phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, bis (4-aminophenyl) phenylamine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl -3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N, N'-bis (4-aminophenyl) -benzidine, N, N'-bis (4-aminophenyl) -N, N '-Dimethyl-benzidine, the following formula (DI)

(In the formula (DI), R ⁵ represents a monovalent organic group having a ring structure containing a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine, and X ¹ represents a divalent organic group. R ⁶ represents an alkyl group having 1 to 4 carbon atoms, and a1 represents an integer of 0 to 3.)
A compound represented by formula (D-II):

(In formula (D-II), R ⁷ represents a divalent organic group having a ring structure containing a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine, and X ² represents a divalent organic group, respectively. A plurality of X ² may be the same or different, R ⁸ represents an alkyl group having 1 to 4 carbon atoms, and a2 represents an integer of 0 to 3, respectively. Show.)
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 the formula (D-III), R ⁹ represents a divalent linking group selected from —O—, —COO—, —OCO—, —NHCO—, —CONH— and —CO—, and R ¹⁰ represents a steroid. R ¹¹ represents a monovalent organic group having a skeleton or a group selected from a skeleton, a trifluoromethylphenyl group, a trifluoromethoxyphenyl group, and a fluorophenyl group, or an alkyl group having 6 to 30 carbon atoms, and R ¹¹ represents 1 to 4 carbon atoms. And a3 represents an integer of 0 to 3.)
Monosubstituted phenylenediamines such as compounds represented by:
The following formula (D-IV)

(In the formula (D-IV), each R ¹² represents a hydrocarbon group having 1 to 12 carbon atoms, and a plurality of R ¹² 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.)
Diaminoorganosiloxanes such as compounds 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.)
And the like, and the like. These other diamines can be used alone or in combination of two or more.
The benzene ring of the aromatic diamine may be substituted with one or two or more alkyl groups having 1 to 4 carbon atoms (preferably a methyl group). In the above formulas (DI), (D-II) and (D-III), R ⁶ , R ⁸ and R ¹¹ are each preferably a methyl group, and a1, a2 and a3 are each 0 Or it is preferable that it is 1, and it is more preferable that it is 0.
(A) Other diamines that can be used to synthesize the polyamic acid include p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1,5- Diaminonaphthalene, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-ditrifluoromethyl-4,4′-diaminobiphenyl, 2,7-diaminofluorene, 4,4′-diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 ′-(p-phenylenediisopropylidene N) 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) to (D-5), 2,6- Diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6- Diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N, N′-bis (4-aminophenyl) -benzidine, , N'- bis (4-aminophenyl) -N, N'- dimethyl benzidine, the expression formula of (D-I) compound represented by (D-6)

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

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

And at least one selected from the group consisting of 1,3-bis (3-aminopropyl) -tetramethyldisiloxane among the compounds represented by each of the above and the compounds represented by the above formula (D-IV) It is preferable.
(A) The diamine that can be used to synthesize the polyamic acid preferably contains 5 mol% or more of the compound represented by the above formula (1) with respect to the total diamine, and contains 10 mol% or more. More preferably, it is more preferably 20 mol% or more.

[(A) Synthesis of polyamic acid]
The polyamic acid (A) contained in the liquid crystal aligning agent of the present invention is represented by the tetracarboxylic acid containing 1,2,3,4-cyclobutanetetracarboxylic dianhydride as described above and the above formula (1). It can be obtained by reacting with a diamine containing a compound.
(A) The proportion of tetracarboxylic dianhydride and diamine used in the polyamic acid synthesis reaction is such that the acid anhydride group of tetracarboxylic dianhydride is equivalent to 1 equivalent of amino group contained in the diamine compound. A ratio of 0.5 to 2 equivalents is preferable, and a ratio of 0.7 to 1.2 equivalents is more preferable.
The synthetic reaction of polyamic acid is preferably carried out in an organic solvent under a temperature condition of -20 to 150 ° C, more preferably 0 to 100 ° C. The reaction time is preferably 0.5 to 48 hours, more preferably 1 to 24 hours. The organic solvent is not particularly limited as long as it can dissolve the synthesized polyamic acid. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ- Examples include aprotic polar solvents such as butyrolactone, tetramethylurea and hexamethylphosphortriamide; phenolic solvents such as m-cresol, xylenol, phenol and halogenated phenol. The amount of organic solvent used (a) is such that the total amount (b) of tetracarboxylic dianhydride and diamine is 0.1 to 30% by weight based on the total amount (a + b) of the reaction solution. It is preferable that In addition, when using an organic solvent together with the poor solvent demonstrated below, the usage-amount (a) of the said organic solvent should be understood as a total amount of an organic solvent and a poor solvent.

For the organic solvent, alcohol, ketone, ester, ether, halogenated hydrocarbon, hydrocarbon and the like, which are poor solvents for polyamic acid, can be used in combination as long as the polyamic acid to be produced does not precipitate. Specific examples of the poor solvent include, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether, ethyl lactate, butyl lactate, Acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, diethyl malonate, diethyl ether, ethylene glycol methyl ether, ethylene Glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n- Chill ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1 , 4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene, isoamylpropionate, isoamylisobutyrate, diisopentyl ether and the like.
When the organic solvent and the poor solvent are used in combination, the proportion of the poor solvent used is preferably 10% by weight or less, more preferably 5% by weight or less, based on the total of the organic solvent and the poor solvent.

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

<(B) Imidized polymer>
The (B) imidized polymer contained in the liquid crystal aligning agent of the present invention can be obtained by dehydrating and ring-closing polyamic acid obtained by reacting tetracarboxylic dianhydride and diamine.
[Tetracarboxylic dianhydride]
(B) As the tetracarboxylic dianhydride used for synthesizing the imidized polymer, (A) the tetracarboxylic dianhydride used for synthesizing the polyamic acid and those exemplified above The same can be mentioned. (B) The tetracarboxylic dianhydride used for synthesizing the imidized polymer may be 1,2,3,4-cyclobutanetetracarboxylic dianhydride among those exemplified above, 2,3, 5-Tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan- 1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan- 1,3-dione, 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′-dione), 5- (2,5 -Dioxotetrahydro-3-furanyl) 3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxynorbornane-2: 3,5: 6-dianhydride and 4,9-dioxatri Includes at least one selected from the group consisting of cyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone (hereinafter referred to as “specific tetracarboxylic dianhydride”). It is preferable.

Particularly preferred specific tetracarboxylic dianhydrides are 2,3,5-tricarboxycyclopentylacetic acid 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.
(B) The tetracarboxylic dianhydride used to synthesize the imidized polymer is 30 mol% or more of the specific tetracarboxylic dianhydride as described above with respect to the total tetracarboxylic dianhydride. It is preferable that it is contained, more preferably 50 mol% or more, and particularly preferably 80 mol% or more.

[Diamine]
(B) Examples of the diamine used for synthesizing the imidized polymer include (A) the same ones as exemplified above as other diamines that can be used for synthesizing the polyamic acid. it can.
(B) Among the compounds exemplified above, the diamine used for synthesizing the imidized polymer is a compound represented by the above formula (D-III), p-phenylenediamine, 4,4′-diaminodiphenylmethane. 4,4′-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-ditrifluoromethyl-4,4′-diaminobiphenyl, 2, , 7-diaminofluorene, 4,4′-diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 '-(P-phenylenediisopropylidene) bisaniline, 4,4'-(m-phenylenediisopropylidene) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis (4-amino) Phenoxy) biphenyl, 1,4-diaminocyclohexane, 4,4′-methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4 -Diaminopyrimidine, 3,6-diaminoacridine, N, N'-bis (4-aminophenyl) -benzidine, N, N'-bis (4-aminophenyl) -N, N'-dimethyl-benzidine, the above formula Of the compounds represented by each of (D-1) to (D-5) and the compound represented by the above formula (DI), the above formula (D-6) 1, of the compounds represented by the formula (D-7), the compound represented by the formula (D-IV), 3-bis (3-aminopropyl) -tetramethyldisiloxane and the like, and it is more preferable that at least one of these is included in a range of 20 mol% or more with respect to the total diamine, and 50 mol% or more is included. More preferably, it is preferable to contain 70 mol% or more.

As the compound represented by the above formula (D-III), compounds represented by the above formulas (D-8) to (D-16) are preferable.
(B) It is preferable that the diamine used for synthesizing the imidized polymer does not include the compound represented by the above formula (1).
(B) The diamine used for synthesizing the imidized polymer is particularly preferably a compound represented by the above formula (D-III), p-phenylenediamine, and 1,3-bis (3-aminopropyl). ) -Tetramethyldisiloxane, 4,4′-diaminodiphenylmethane, 2,2′-dimethyl-4,4′-diaminobiphenyl and diamine comprising at least one selected from the group consisting of 4,4′-diaminodiphenyl ether Among them, the compound represented by the above formula (D-III) is preferably contained in an amount of 0.5 to 40 mol%, particularly preferably 1 to 15 mol%, based on the total diamine.

[Synthesis of (B) imidized polymer]
(B) The imidized polymer can be obtained by dehydrating and ring-closing the polyamic acid obtained by reacting the tetracarboxylic dianhydride and diamine as described above. Here, the reaction of tetracarboxylic dianhydride and diamine can be carried out in the same manner as described above as the method for synthesizing (A) polyamic acid.
For example, (i) a method in which polyamic acid is heated, (ii) a method in which polyamic acid is dissolved in an organic solvent, a dehydrating agent and a dehydrating ring-closing catalyst are added to the solution, and heating is performed as necessary. Etc.
The reaction temperature in the method of heating the polyamic acid (i) is preferably 50 to 200 ° C, more preferably 60 to 170 ° C. When the reaction temperature is less than 50 ° C., the dehydration ring-closing reaction does not proceed sufficiently, and when the reaction temperature exceeds 200 ° C., the molecular weight of the imidized polymer obtained may decrease. The reaction time is preferably 0.5 to 24 hours, more preferably 1 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. It is preferable that the usage-amount of a dehydrating agent shall be 0.01-20 mol with respect to 1 mol of repeating units 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. It is preferable that the usage-amount of a dehydration ring-closing catalyst shall be 0.01-10 mol with respect to 1 mol of dehydrating agents to be used. In addition, as an organic solvent used for dehydration ring closure reaction, the organic solvent illustrated as what is used for the synthesis | combination of a polyamic acid can be mentioned. And the reaction temperature of dehydration ring closure reaction becomes like this. Preferably it is 0-180 degreeC, More preferably, it is 10-150 degreeC. The reaction time is preferably 0.5 to 24 hours, more preferably 1 to 12 hours.

The (B) imidized polymer obtained in the above method (i) may be used for the preparation of a liquid crystal aligning agent as it is, or after the obtained imidized polymer is purified, it is used for the preparation of a liquid crystal aligning agent. May be. On the other hand, in the method (ii), a reaction solution containing an imidized polymer is obtained. This reaction solution may be directly used for the preparation of the liquid crystal aligning agent, or may be used for the preparation of the liquid crystal aligning agent after removing the dehydrating agent and the dehydrating ring-closing catalyst from the reaction solution. After separating, it may be used for preparing a liquid crystal aligning agent, or the isolated imidized polymer may be purified and then used for preparing a liquid crystal aligning agent. 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. (B) Isolation and purification of the imidized polymer can be performed by performing the same operation as described above as the method for isolating and purifying (A) polyamic acid.
The (B) imidized polymer 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 the amic acid structure A partially imidized product in which only a part of is dehydrated and closed and an amic acid structure and an imide ring structure coexist may be used.
The (B) imidized polymer contained in the liquid crystal aligning agent of the present invention preferably has an imidization rate of 40% or more, and more preferably 80% or more. Here, the “imidation rate” is a percentage of the number of imide ring structures to the total of the number of amic acid structures and the number of imide ring structures in the imidized polymer. At this time, a part of the imide ring may be an isoimide ring.

[End-modified polymer]
The (A) polyamic acid and (B) imidized polymer may each be a terminal-modified polymer having a controlled molecular weight. When such a terminal-modified polymer is synthesized with a polyamic acid ((A) polyamic acid or (B) polyamic acid as a precursor of an imidized polymer), acid monoanhydride, It can be synthesized by adding a monoamine compound, a monoisocyanate compound or the like to the reaction system. Here, as the acid monoanhydride, for example, maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride , N-hexadecyl succinic anhydride and the like. Examples of the monoamine compound include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, and n-undecyl. Amine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine, etc. be able to. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate. The use ratio of the molecular weight regulator as described above is preferably 10 parts by weight or less, more preferably 100 parts by weight or less, more preferably 100 parts by weight of the total of tetracarboxylic dianhydride and diamine used when synthesizing the polyamic acid. 5 parts by weight or less.

[Solution viscosity]
The (A) polyamic acid and the (B) imidized polymer preferably have a solution viscosity of 20 to 800 mPa · s, respectively, when this is a 10% by weight solution. More preferably, it has a solution viscosity of 500 mPa · s.
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.
[Use ratio of (A) polyamic acid and (B) imidized polymer]
The liquid crystal aligning agent of the present invention contains (A) polyamic acid and (B) imidized polymer as described above, and the ratio of use thereof depends on the number of (A) the number of amic acid structures possessed by polyamic acid and (B The ratio of the number of imide rings of the (B) imidized polymer to the total number of imide rings and imamic acid structures of the imidized polymer (hereinafter referred to as “average imidization ratio”) is 10 to 10. The ratio is 50%. The average imidization rate is preferably 10 to 40%.
By adjusting the use ratio of (A) polyamic acid and (B) imidized polymer in the above range, good image sticking characteristics, that is, image sticking immediately after release of charge stress is suppressed, and the liquid crystal alignment film is excellent in image sticking relaxation properties. The liquid crystal aligning agent which gives can be made.

<Other ingredients>
As described above, the liquid crystal aligning agent of the present invention contains (A) a polyamic acid and (B) an imidized polymer in the above proportions, but other than these unless the effects and advantages of the present invention are impaired. May contain other components. Examples of such other components 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 said epoxy compound can be contained in the liquid crystal aligning agent of this invention from a viewpoint of improving the adhesiveness with respect to the substrate surface of the liquid crystal aligning film formed. Examples of such epoxy compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and 1,6-hexane. Diol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N, N ′, N′— Tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-4,4′-dia Bruno diphenylmethane, N, N-diglycidyl - benzylamine, N, N-diglycidyl - aminomethyl cyclohexane, etc., it may be mentioned as being preferred. The blending ratio of these epoxy compounds is preferably 40 parts by weight or less with respect to 100 parts by weight of the polymer (the total of (A) polyamic acid and (B) imidized polymer). Preferably it is 0.1-30 weight part.

Examples of the functional silane compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl)- 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyl Trimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4 7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N- Benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis ( Examples thereof include oxyethylene) -3-aminopropyltrimethoxysilane and N-bis (oxyethylene) -3-aminopropyltriethoxysilane.
The blending ratio of these functional silane compounds is preferably 2 parts by weight or less, more preferably 0.2 parts by weight or less, with respect to 100 parts by weight of the total polymer.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of the present invention contains (A) polyamic acid and (B) imidized polymer as essential components as described above, and further contains other components depending on the case, but each component is an organic solvent. It is preferable to be constituted by being dissolved and contained therein.
As an organic solvent which can be used for the liquid crystal aligning agent of this invention, the solvent illustrated as what is used for the synthesis reaction of (A) polyamic acid can be mentioned. Moreover, the poor solvent illustrated as what can be used together in the synthesis reaction of (A) polyamic acid can also be selected suitably, and can be used together.
Preferred organic solvents used in the liquid crystal aligning agent of the present invention include, for example, 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 Examples thereof include dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, isoamyl propionate, isoamyl isobutyrate, and diisopentyl ether. These can be used alone or in admixture of two or more.

A particularly preferable solvent composition is a solvent composition obtained by combining the above-mentioned solvents, in which each component does not precipitate in the liquid crystal aligning agent, and the surface tension of the liquid crystal aligning agent is in the range of 25 to 40 mN / m. The solvent composition.
The solid content concentration of the liquid crystal aligning agent of the present invention, that is, the ratio of the total weight of components other than the organic 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. However, it is preferably in the range of 1 to 10% by weight. That is, when the liquid crystal aligning agent of the present invention is applied to the substrate surface and the organic solvent is removed to form a coating film that becomes a liquid crystal aligning film, the solid content concentration is less than 1% by weight. The film thickness of this coating film may be 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. Similarly, it may be difficult to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal aligning agent may increase, resulting in poor coating characteristics.
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 range of 1.5 to 4.5% by weight is particularly preferable. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by weight, and thereby the solution viscosity is in the range of 12 to 50 mPa · s. In the case of the ink jet method, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by weight, and thereby the solution viscosity is in the range of 3 to 15 mPa · s.
The temperature at which the liquid crystal aligning agent of the present invention is prepared is preferably 0 ° C to 100 ° C, more preferably 20 ° C to 60 ° C.

<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) First, the liquid crystal alignment film of the present invention is applied onto a pair of substrates, and the solvent is removed to form a coating film. Here, when the display mode of the liquid crystal display element to be manufactured is a vertical electric field system such as a TN type, an STN type, or a VA type, two substrates on which a transparent conductive film patterned on one side is provided. Are used as a pair of substrates. On the other hand, when the display mode of the liquid crystal display element to be manufactured is a horizontal electric field method, a pair of a substrate provided with a transparent conductive film having a comb-like pattern and a substrate not having a transparent conductive film is used. Used as a substrate.
In any of the above cases, the liquid crystal aligning agent is applied onto the substrate (on the surface having the transparent conductive film of the substrate when the substrate has a transparent conductive film). As the substrate, for example, glass such as float glass or soda glass; a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, poly (cycloaliphatic olefin) can be used. Examples of the transparent conductive film provided on one surface of the substrate include 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 ), and the like. Can be used. In addition, in order to obtain these patterned transparent conductive films, a method of forming a pattern by a photo-etching method after forming a transparent conductive film without a pattern, and a mask having a desired pattern when forming the transparent conductive film. For example, a method of directly forming a patterned transparent conductive film can be employed.
The liquid crystal aligning agent is applied onto the substrate by an appropriate application method such as a roll coater method, a spinner method, a printing method, or an ink jet method. 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, a functional titanium compound, or the like is applied in advance to the coated surface of the substrate. You may keep it.

After application, preheating (pre-baking) is preferably performed for the purpose of preventing dripping of the applied alignment agent. The pre-baking temperature is preferably 30 to 200 ° C, more preferably 40 to 150 ° C, and particularly preferably 40 to 100 ° C. The pre-bake time should be appropriately set according to the type of heating equipment to be used. For example, when a hot plate is used, it is preferably 45 seconds to 30 minutes, more preferably 45 seconds to 20 minutes. It is. Thereafter, a baking (post-baking) step is performed for the purpose of completely removing the solvent. In addition to the purpose of completely removing the solvent from the coating film, this Portobake further promotes dehydration and cyclization of the amic acid structure of the polymer contained in the liquid crystal aligning agent of the present invention by heating. It can also be performed for the purpose of further increasing the imidization rate. The post-baking temperature is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. The post-bake time should be appropriately set depending on the type of heating equipment to be used. For example, when a hot plate is used, it is preferably 3 to 60 minutes, more preferably 7 to 30 minutes. is there.
Thus, the coating film used as a liquid crystal aligning film can be formed. The film thickness of the formed coating film is preferably 0.001-1 μm, more preferably 0.005-0.5 μm.
When the liquid crystal display element to which the liquid crystal aligning agent of the present invention is applied is a VA type liquid crystal display element, a projecting building as described in, for example, Patent Document 7 (Japanese Patent Laid-Open No. 2002-327058) is used. After forming on a substrate, a liquid crystal aligning agent may be applied to improve viewing angle characteristics.

(2) When the display mode of the liquid crystal display element to be manufactured is the VA type, the coating film formed as described above can be used as a liquid crystal alignment film as it is. The rubbing process described may be performed. On the other hand, when the display mode of the liquid crystal display element to be manufactured is a vertical electric field method other than the VA type or a horizontal electric field method, a rubbing process is performed on the formed coating film surface.
The rubbing treatment can be performed by a method of rubbing in a certain direction with a roll around which a cloth made of fibers such as nylon, rayon, and cotton is wound. Thereby, the orientation ability of a liquid crystal molecule is provided to a coating film, and it becomes a liquid crystal aligning film. Furthermore, a part of the liquid crystal alignment film as shown in, for example, Patent Document 8 (Japanese Patent Laid-Open No. 6-222366) or Patent Document 9 (Japanese Patent Laid-Open No. 6-281937) is applied to the coating film after the rubbing treatment. Or a part of the surface of the liquid crystal alignment film as disclosed in Patent Document 10 (Japanese Patent Laid-Open No. 5-107544) By forming a resist film on the top and performing a rubbing treatment in a direction different from the previous rubbing treatment, and then removing the resist film so that the liquid crystal alignment film has different liquid crystal alignment capabilities for each region, It is possible to improve the visibility characteristics of the obtained liquid crystal display element.

(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 facing each other. Here, when the rubbing process is performed on the coating film, the two substrates are disposed to face each other so that the rubbing directions in the respective coating films 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, or the like can be used, and among these, a nematic liquid crystal is preferable. In the case of a VA liquid crystal cell, a nematic liquid crystal having negative dielectric anisotropy is preferable. For example, a dicyanobenzene liquid crystal, a pyridazine liquid crystal, a Schiff base liquid crystal, an azoxy liquid crystal, a biphenyl liquid crystal, or a phenylcyclohexane liquid crystal is used. It is done. In the case of a TN type liquid crystal cell or an STN type liquid crystal cell, a nematic type liquid crystal having positive dielectric anisotropy is preferable. For example, biphenyl type liquid crystal, phenyl cyclohexane type liquid crystal, ester type liquid crystal, terphenyl type liquid crystal, biphenyl cyclohexane type A liquid crystal, a pyrimidine liquid crystal, a dioxane liquid crystal, a bicyclooctane liquid crystal, a cubane liquid crystal, or the like is used. For example, 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); p-decyloxybenzylidene Ferroelectric liquid crystals such as -p-amino-2-methylbutyl cinnamate 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.
The polymer solution viscosity in the following synthesis examples is a value measured at 25 ° C. using an E-type viscometer for the heavy duty solution pointed out in each synthesis example.
The imidation rate of the imidized polymer was calculated by the following formula from ¹ H-NMR measured at room temperature using tetramethylsilane as a reference substance after the imidized polymer was dried under reduced pressure at room temperature and then dissolved in deuterated dimethyl sulfoxide. Obtained by (i).

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 in the vicinity of 10 ppm, A ² is a peak area derived from other protons, and α is a precursor of an imidized polymer (polyamic acid). The number ratio of other protons to one proton of NH group in)
<(A) Synthesis of polyamic acid>
Synthesis example 1
200 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 150 g of 2,2′-dimethyl-4,4′-diaminobiphenyl as diamine (0. 7 mol) and 4,4′-diaminobenzanilide 68 g (0.3 mol) are dissolved in a mixed solvent consisting of 3,300 g of γ-butyrolactone and 370 g of N-methyl-2-pyrrolidone, and the reaction is carried out at 40 ° C. for 3 hours. By performing, about 4,000 g of a solution containing 10% by weight of polyamic acid (A-1) was obtained. The solution viscosity of this solution was 190 mPa · s.

<Comparative synthesis example of polyamic acid>
Synthesis example 2
200 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 210 g of 2,2′-dimethyl-4,4′-diaminobiphenyl as diamine (1. 0 mol) is dissolved in a mixed solvent consisting of 370 g of N-methyl-2-pyrrolidone and 3,300 g of γ-butyrolactone, and reacted at 40 ° C. for 3 hours to contain 10% by weight of polyamic acid (A-2) About 3,700 g of a solution was obtained. The solution viscosity of this solution was 160 mPa · s.
Synthesis example 3
1,2,3,4-Cyclobutanetetracarboxylic dianhydride 98 g (0.50 mol) and pyromellitic dianhydride 110 g (0.50 mol) as tetracarboxylic dianhydride and 4,4 ′ as diamine -200 g (1.0 mol) of diaminodiphenylmethane was dissolved in a mixed solvent consisting of 230 g of N-methyl-2-pyrrolidone and 2,100 g of γ-butyrolactone, reacted at 40 ° C. for 3 hours, γ-butyrolactone 1, By adding 350 g, about 3,800 g of a solution containing 10% by weight of polyamic acid (A-3) was obtained. The solution viscosity of this solution was 125 mPa · s.

<(B) Synthesis of imidized polymer>
Synthesis example 4
110 g (0.50 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro -2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione 160 g (0.50 mol), p-phenylenediamine 94 g (0.87 mol) as diamine, 1, 25 g (0.10 mol) of 3-bis (3-aminopropyl) tetramethyldisiloxane and 9.6 g (0.015 mol) of 3,6-bis (4-aminobenzoyloxy) cholestane and octadecylamine as monoamine. 1 g (0.030 mol) was dissolved in 960 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours, To obtain a solution containing click acid. A small amount of the obtained polyamic acid solution was collected, and N-methyl-2-pyrrolidone was added to measure the solution viscosity as a solution having a polyamic acid concentration of 10% by weight of 60 mPa · s.
Next, 2,700 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 400 g of pyridine and 410 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with new γ-butyrolactone (by this solvent replacement operation, pyridine and acetic anhydride used in the dehydration ring closure reaction were removed from the system, the same applies hereinafter). Thus, about 2,400 g of a solution containing 15% by weight of the imidized polymer (B-1) having an imidation ratio of about 95% was obtained. A small amount of this imidized polymer solution was taken, and γ-butyrolactone was added thereto to measure the solution viscosity as a solution having an imidized polymer content of 10% by weight. The solution viscosity was 70 mPa · s, and the imidized polymer content was 6.0% by weight. The solution viscosity measured as a solution was 16.0 mPa · s.

Synthesis example 5
2,3,5-tricarboxycyclopentyl acetic acid dianhydride 112 g (0.50 mol) and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro) as tetracarboxylic dianhydride -2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione 157 g (0.50 mol), p-phenylenediamine 88 g (0.81 mol) as diamine, bisamino 25 g (0.10 mol) of propyltetramethyldisiloxane and 35 g (0.080 mol) of 4- (4′-trifluoromethoxybenzoyloxy) cyclohexyl-3,5-diaminobenzoate and 1.4 g of aniline as monoamine (0 .015 mol) is dissolved in 1,250 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours. Thus, a solution containing a polyamic acid 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 polyamic acid concentration of 10% by weight was 55 mPa · s.
To the obtained polyamic acid solution, 2,500 g of N-methyl-2-pyrrolidone was added, 400 g of pyridine and 408 g of acetic anhydride were further 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 new N-methyl-2-pyrrolidone, whereby a solution containing about 17% by weight of an imidized polymer (B-2) having an imidization rate of 95% was obtained. , 800 g 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 an imidized polymer concentration of 6.0% by weight was 13.0 mPa · s.

Synthesis Example 6
224 g (1.0 mol) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride as tetracarboxylic dianhydride and 106 g (0.99 mol) of p-phenylenediamine as diamine and cholestayl-3,5- 7.8 g (0.015 mol) of diaminobenzoate was dissolved in 3,050 g of N-methyl-2-pyrrolidone and reacted at room temperature for 3 hours to obtain a polyamic acid solution having a solution viscosity of 210 mPa · s.
Next, 3,400 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 400 g of pyridine and 300 g of acetic anhydride were further 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 new γ-butyrolactone to obtain 3,100 g of a solution containing 9% by weight of polyimide (B-4) having an imidization ratio of 90%. 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 3.1% by weight of 15.0 mPa · s.

Example 1
<Preparation of liquid crystal aligning agent>
The quantity which converted the solution containing the polyamic acid (A-1) obtained by the said synthesis example 1 and the solution containing the polyimide (B-1) obtained by the said synthesis example 3 into the polymer which each contains. Are mixed such that (A-1) :( B-1) = 80: 20 (weight ratio), where γ-butyrolactone (BL), N-methyl-2-pyrrolidone (NMP) and butyl cellosolve (BC ), And 2 parts by weight of N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane as an epoxy compound is added to a total of 100 parts by weight of the polymer, and the solvent composition is BL: A solution having NMP: BC = 71: 17: 12 (weight ratio) and a solid concentration of 6% by weight was obtained. A liquid crystal aligning agent (S-1) was prepared by filtering this solution using a filter having a pore diameter of 1 μm.
In addition, the average imidation ratio of the polymer in the liquid crystal aligning agent (S-1) was 19%.
<Manufacture of liquid crystal cells>
The liquid crystal aligning agent (S-1) prepared above was applied onto the transparent electrode surface of the glass substrate with a transparent electrode made of an ITO film by a spinner, then pre-baked at 80 ° C. for 1 minute, and further post-baked at 210 ° C. for 10 minutes. As a result, a coating film having a film thickness of 60 nm was formed. The coating film was rubbed using a rubbing machine having a roll wrapped with a rayon cloth under the conditions of a roll rotation speed of 400 rpm, a stage moving speed of 3 cm / second, and a hair foot indentation length of 0.4 mm. Next, this substrate was ultrasonically cleaned in ultrapure water for 1 minute and dried in a clean oven at 100 ° C. for 10 minutes to form a liquid crystal alignment film on the transparent electrode surface of the glass substrate. This operation was repeated to produce a pair (two) of glass substrates having a liquid crystal alignment film on the transparent electrode surface.
After applying an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm to the outer edge of the surface having the liquid crystal alignment film of each of the pair of substrates, the liquid crystal alignment film surfaces face each other and the liquid crystal alignment film of both substrates has The adhesive was cured by overlapping and pressing so that the rubbing direction was perpendicular. Next, after filling nematic liquid crystal (MLC-6221 manufactured by Merck & Co., Inc.) between a pair of substrates from the liquid crystal injection port, the liquid crystal injection port is sealed with an acrylic photo-curing adhesive to produce a liquid crystal cell. did.

<Evaluation of voltage holding ratio>
With respect to the liquid crystal cell produced above, a voltage of 5 V was applied at 60 ° C. with an application time of 60 microseconds and a span of 167 milliseconds, and then the voltage holding ratio after 167 milliseconds from the release of application was measured. As a measuring device, VHR-1 manufactured by Toyo Corporation was used.
In Table 1, “> 99” indicates that the measured value of the voltage holding ratio exceeds 99% and is 100% or less.
<Evaluation of seizure characteristics>
A liquid crystal cell was produced in the same manner as described above except that a substrate having a transparent electrode with a pattern as shown in FIG. 1 was used.
[Evaluation of seizure characteristics immediately after release of charge stress]
For this liquid crystal cell, a DC voltage of 17 V was applied to the electrode A and a DC voltage of 0 V was applied to the electrode B for 20 hours at 25 ° C. Immediately after the voltage application was canceled, a direct current voltage of 0.1 to 3.0 V was applied to the electrodes A and B in increments of 0.1 V. At this time, the luminance difference between the two electrodes at each voltage was examined, and the burn-in characteristic immediately after the release of the charge stress was evaluated at a voltage at which the luminance difference between the electrodes was the largest. That is, when the difference in brightness between the electrodes is not observed, the image sticking characteristic “excellent” immediately after the stress is released, and when the difference in brightness is slightly observed, the image sticking characteristic “good”, when the difference in brightness is clearly observed. The seizure characteristic was “bad”. The results are shown in Table 1.
[Evaluation of seizure mitigation]
The liquid crystal cell subjected to the evaluation of the image sticking property was allowed to stand at 25 ° C. for 2 days (48 hours) after releasing the charge stress. Thereafter, a voltage having the largest luminance difference between the two voltages in the evaluation of the burn-in characteristic immediately after the release of the charge stress was applied to the electrodes A and B, and the luminance difference between the two electrodes was examined. About this brightness | luminance difference, the result evaluated in three steps similarly to the said reference | standard was made into the evaluation result of burn-in relaxation. The results are shown in Table 1.

Example 2 and Comparative Examples 1-5
As the polymer-containing solution, a solution containing the polymer shown in Table 1 was used in such an amount that the weight converted into the polymer contained in the polymer was a value shown in Table 1, respectively. In the same manner as in Example 1, liquid crystal aligning agents (S-2) and (R-1) to (R-5) were prepared and evaluated. The evaluation results are shown in Table 1.

Schematic explanatory drawing which shows the pattern of the transparent electrode for image sticking characteristic evaluation.

Claims (5)

(A) tetracarboxylic dianhydride including 1,2,3,4-cyclobutanetetracarboxylic dianhydride, and the following formula (1)

(In Formula (1), R ^I and R ^II are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
And (B) a polyamic acid obtained by reacting a diamine containing a compound represented by formula (B), and an imidized polymer of polyamic acid obtained by reacting a tetracarboxylic dianhydride and a diamine, and ( The ratio of the number of imide rings of (B) imidized polymer to the total of A) the number of amic acid structures possessed by polyamic acid and (B) the number of imide rings possessed by imidized polymer and the number of amic acid structures The liquid crystal aligning agent characterized by being 10 to 50%.   (B) Tetracarboxylic dianhydrides for synthesizing imidized polymers are 2,3,5-tricarboxycyclopentyl acetic dianhydride and 1,3,3a, 4,5,9b-hexahydro-8- 2. It contains at least one selected from the group consisting of methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione. Liquid crystal aligning agent as described in.   The compound further comprising at least one epoxy group in the molecule in the range of 0.1 to 30 parts by weight with respect to 100 parts by weight in total of (A) polyamic acid and (B) imidized polymer. The liquid crystal aligning agent of 1 or 2.   The liquid crystal aligning film formed from the liquid crystal aligning agent as described in any one of Claims 1-3.   A liquid crystal display element comprising the liquid crystal alignment film according to claim 4.

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