JP2943531B2 - Liquid crystal alignment film, liquid crystal holding substrate and liquid crystal display element having the same, and material for liquid crystal alignment film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal alignment film, a liquid crystal sandwiching substrate having the same, a liquid crystal display device, and a material for the liquid crystal alignment film.

[0002]

2. Description of the Related Art Conventionally, an STN (super twisted nematic) system has been used for a liquid crystal display element for a large display in order to improve visual characteristics. this is,
The long axis direction of the liquid crystal molecules is twisted by 240 to 270 ° in the cell (240 to 270 ° twist). An alignment film material that can stably obtain a high pretilt angle is indispensable for manufacturing an STN mode liquid crystal display element. Further, with the development of color display elements, there is a demand for an alignment film material that can form a film at a low curing temperature due to the limitation on heat resistance of a color filter. Therefore, in order to obtain an alignment film having such a high pretilt angle, (1) a method using a polyimide in which a fluoroalkyl group is bonded to a chain carbon (Japanese Patent Laid-Open No. 62-1)
No. 74725, U.S. Pat. No. 4,735,492), and (2) a method of adding an amine compound having a long-chain fluoroalkyl group to a polyimide (JP-A-1-18005).
No. 18), (3) Method of adding a metal complex having a long-chain fluoroalkyl group (Proceedings of the 13th Symposium on Liquid Crystal Symposium 1)
October 987) and the like. However, any of these methods has a disadvantage that a stable pretilt angle cannot be obtained.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and provides a liquid crystal alignment film stably exhibiting a high pretilt angle at a relatively low curing temperature, a liquid crystal holding substrate having the same, and a liquid crystal. It is intended to provide a display element and a composition for a liquid crystal alignment film.

[0004]

Means for Solving the Problems The liquid crystal alignment film of the present invention is represented by the following general formula (I):

Embedded image [Wherein, in the general formula (I), n is an integer of 2 to 16, and R represents a divalent organic group].

The above-mentioned polyimide is represented by the general formula (II) in addition to the structural unit represented by the general formula (I):

Embedded image [However, in the general formula (II), A represents a tetravalent residue of a tetracarboxylic dianhydride having an alicyclic structure, and R ′ represents a divalent organic group.] Is preferred.

The above-mentioned polyimide is represented by the following general formula (III) in addition to the structural unit represented by the general formula (I) and the structural unit represented by the general formula (II).

Embedded image [However, in the general formula (III), B represents a tetravalent residue of a tetracarboxylic dianhydride other than the tetravalent residue of the tetracarboxylic dianhydride in the general formulas (I) and (II). ,
R ″ represents a divalent organic group].

[0007] The polyimide preferably contains 5 to 100 mol%, more preferably 20 to 100 mol% of the structural unit represented by the general formula (I). Further, the polyimide preferably contains 5 to 95 mol% of the structural unit represented by the general formula (I) and 5 to 95 mol% of the structural unit represented by the general formula (II). It is preferred to contain 20 to 80 mol% of the structural unit represented by the formula (II) and 20 to 80 mol% of the structural unit represented by the formula (II). In the above, the structural unit represented by the general formula (III) can be appropriately contained so that the total amount is 100 mol%. Polyimide containing too few structural units represented by the general formula (I) tends to have a lower pretilt angle. In addition, polyimide having too few structural units represented by the general formula (II) tends to have a low voltage holding ratio. Here, the charge retention is as follows. TV
Display, matrix display, a large number of pixel electrodes,
Active type twisted nematic liquid crystal display elements using an electrode substrate incorporating a number of MIM elements (metal-insulating layer-metal field effect element) for performing on-off and TFT (field-effect thin film transistor) elements are known. In such an active liquid crystal display element, a drain voltage is generated by applying a pulse to the gate of the TFT.
The drain voltage gradually decreases until the next pulse application. The degree to which the drain voltage decreases is referred to as the voltage holding ratio. In order to obtain good display characteristics with an active liquid crystal display device, the voltage holding ratio is preferably as high as possible.

The liquid crystal alignment film is formed of ITO (Indium Tin Oxi).
The substrate is formed on an electrode substrate such as a glass plate provided with a transparent electrode such as de), and a pair of the substrates is opposed to each other, and a liquid crystal is sandwiched between the electrode substrates to form a liquid crystal sandwiching substrate.

Further, a liquid crystal display device having a liquid crystal holding substrate can be obtained by a known method using the above liquid crystal holding substrate.

The liquid crystal alignment film can be manufactured by using a liquid crystal alignment film material containing a polyamic acid which is a precursor of polyimide. This polyamic acid is represented by the following chemical formula 1.
0 [General formula (I ')]

Embedded image [However, in the general formula (I '), n and R represent the general formula (I)
The same applies to the above.).

The above polyamic acid is represented by the above general formula (I ')
With the structural unit represented by the general formula (I
I '))

Embedded image [However, in the general formula (II '), A and R'
It is the same as I)].

The polyamic acid is represented by the following general formula (III '), in addition to the structural unit represented by the general formula (I') and the structural unit represented by the general formula (II ').

Embedded image [However, in the general formula (III '), B and R "
The same applies to II)].

The polyamic acid has the general formula (I ')
It is preferable to contain 5 to 100 mol% of the structural unit represented by the formula, and particularly preferable to contain 20 to 100 mol%. Further, the polyimide preferably contains 5 to 95 mol% of the structural unit represented by the general formula (I ') and 5 to 95 mol% of the structural unit represented by the general formula (II'). ') And 20 to 80 mol% of the structural unit represented by the general formula (II'). In the above, the structural unit represented by the general formula (III ′) can be appropriately contained so that the total amount is 100 mol%.

The liquid crystal alignment film can be manufactured using a liquid crystal alignment film material containing a polyimide resin described below. The polyimide resin is a general term for the above-mentioned polyimide and its precursor. Examples of the polyimide precursor include the above-mentioned polyamic acid and a partially imidized polyamic acid.

The above polyimide resin is represented by the following formula (IV):

Embedded image [However, in the general formula (IV), n represents an integer of 2 to 16]. The compound can be produced by reacting an acid component containing a tetracarboxylic dianhydride and a diamine compound.

In the production of the above-mentioned polyimide resin, the acid component together with the tetracarboxylic dianhydride represented by the general formula (IV) is represented by the following general formula (V):

Embedded image [However, in the general formula (V), A represents a tetravalent residue of a tetracarboxylic dianhydride having an alicyclic structure.] It is preferable to use a tetracarboxylic dianhydride represented by the following formula:

In the production of the polyimide resin, the acid component preferably contains 5 to 100 mol% of the tetracarboxylic dianhydride represented by the general formula (IV).
It is particularly preferable to contain 20 to 100 mol%. further,
In the polyimide, the tetracarboxylic dianhydride represented by the general formula (IV) is 5 to 95 mol% and the tetracarboxylic dianhydride represented by the general formula (V) is 5 to 9 mol%.
It is preferable to contain 5 mol%, especially 20 to 80 mol% of the structural unit represented by the general formula (IV) and the above-mentioned general formula (V)
Preferably contains 20 to 80 mol% of the tetracarboxylic dianhydride represented by the formula: In the above, a tetracarboxylic dianhydride other than the tetracarboxylic dianhydride represented by the general formula (IV) or (V) can be appropriately contained so that the total amount becomes 100 mol%.

The tetracarboxylic dianhydride represented by the general formula (IV) includes ethylene glycol bis (trimellitic anhydride), 1,3-propanediol bis (trimellitic anhydride), 1,4 -Butanediol bis (trimellitic anhydride), 1,5-pentanediol bis (trimellitic anhydride), 1,6-hexanediol bis (trimellitic anhydride), 1,8-octanediol bis ( Trimellitic anhydride), 1,10-
Decanediol bis (trimellitic anhydride), 1,1
6-hexadecanediol bis (trimellitic anhydride) and the like. These may be used in combination of two or more.

The tetracarboxylic dianhydride represented by the above general formula (V) includes butane-1,2,3,4-tetracarboxylic dianhydride, cyclobutane-1,2,3,
4-tetracarboxylic dianhydride, cyclopentane-1,
2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, 3,
4,3 ', 4'-bicyclohexyltetracarboxylic dianhydride, bis [bicyclo (2,2,1) hepta-2,3-
Dicarboxylic anhydride] sulfone, 1,3-di (3,4-dicarboxycyclohexyl) cyclohexanol dianhydride, bicyclo (2,2,1) hepta-2,3,5,6-
Tetracarboxylic dianhydride, bicyclo (2,2,2) oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, decahydronaphthalene-1,4,5,8-tetracarboxylic Acid dianhydride, 4,8-dimethyl-1,2,2
3,5,6,7-hexahydronaphthalene-, 1,2,2
5,6-tetracarboxylic dianhydride and the like. These may be used in combination of two or more.

Examples of the tetracarboxylic dianhydride other than the tetracarboxylic dianhydride represented by the general formula (IV) or (V) include pyromellitic anhydride,
3 ', 4,4'-diphenyltetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,3,6,7, -naphthalenetetracarboxylic dianhydride, 2,2 ', 3,3'-diphenyltetracarboxylic dianhydride, 2,2-bis (3,4, -dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride Anhydride, 3,4,9,1
O-perylenetetracarboxylic dianhydride, bis (3,4
-Dicarboxyphenyl) ether dianhydride, naphthalene-1,2,4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride,
2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,7-dichloronaphthalene-
1,4,5,8, tetracarboxylic dianhydride, 2,3
6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, phenanthrene-1,8,
9,10-tetracarboxylic dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride,
1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride Anhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride,

Benzene-1,2,3,4-tetracarboxylic dianhydride, 3,4,3 ', 4'-benzophenonetetracarboxylic dianhydride, 2,3,2', 3-benzophenonetetracarboxylic Acid dianhydride, 2,3,3 ', 4'
-Benzonephenone tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride,
Ethylene tetracarboxylic dianhydride, 2,3,3 ',
4′-biphenyltetracarboxylic dianhydride, 3,4
3 ′, 4′-biphenyltetracarboxylic dianhydride,
2,3,2 ', 3'-biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) dimethylsilane dianhydride, bis (3,4-dicarboxyphenyl) methylphenylsilane dianhydride , Bis (3,4-dicarboxyphenyl) diphenylsilane dianhydride, bis (2,3-dicarboxyphenyl) dimethylsilane dianhydride, 1,4-bis (3,4-dicarboxyphenyldimethylsilyl) benzene Dianhydride, 1,3-bis (3,4
-Dicarboxyphenyl) -1,1,3,3-tetramethyldicycloxane dianhydride, p-phenylbis (trimellitic acid monoester anhydride), 4,4'-bis (3,4-di (Carboxyphenoxy) diphenylsulfide dianhydride, 2,2-bis (2,3-dicarboxyphenyl) hexafluoropropane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride Anhydride, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] hexafluoropropane dianhydride, 1,4-bis (2-hydroxyhexafluoropropyl) benzenebistrimellitic dianhydride,
1,3-bis (2-hydroxyhexafluoropropyl) benzenebistrimellitic dianhydride,

(Trifluoromethyl) pyromellitic dianhydride, bis (trifluoromethyl) pyromellitic dianhydride, 5,5'-bis (trifluoromethyl) -3,
3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2', 5,5'-tetrakis (trifluoromethyl) -3,3 ', 4,4'-biphenyltetracarboxylic dianhydride , 5,5'-bis (trifluoromethyl)-
3,3 ', 4,4'-diphenylethertetracarboxylic dianhydride, 5,5'-bis (trifluoromethyl)
-3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, bis {(trifluoromethyl) dicarboxyphenoxy} benzene dianhydride, bis {(trifluoromethyl) dicarboxyphenoxy} biphenyl dianhydride , Bis {(trifluoromethyl) dicarboxyphenoxy} (trifluoromethyl) benzene dianhydride, bis {(trifluoromethyl) dicarboxyphenoxy} bis (trifluoromethyl) biphenyl dianhydride, bis {(trifluoromethyl) ) Dicarboxyphenoxy diphenylether dianhydride, bis (dicarboxyphenoxy) (trifluoromethyl) benzene dianhydride, bis
(Dicarboxyphenoxy) bis (trifluoromethyl) benzene dianhydride, bis (dicarboxyphenoxy) tetrakis (trifluoromethyl) benzene dianhydride, bis (dicarboxyphenoxy) bis (trifluoromethyl) biphenyl dianhydride, Bis (dicarboxyphenoxy) tetrakis (trifluoromethyl) biphenyl dianhydride; These may be used in combination of two or more.

As the diamine compound, 4- (4-
Aminophenyl) -3-aminobenzoic acid, 2,2-bis (4-aminophenyl) propane, 2,6-diaminopyridine, bis (4-aminophenyl) diethylsilane,
Bis- (4-aminophenyl) diphenylsilane, bis- (4-aminophenyl) ethylphosphine oxide, bis- (4-aminophenyl) -N-butylamine, bis- (4-aminophenyl) -N-methylamine, N- (3-aminophenyl) -4-aminobenzamide, 3,3'-diaminodiphenylmethane, 3,3 '
-Diaminodiphenyl ether, 3,3'-diaminodiphenylsulfone, 3,3'-diaminodiphenylpropane, 3,3'-diaminodiphenylsulfide, p-
Phenylenediamine, m-phenylenediamine, m-xylenediamine, 2,4-diaminotoluene, 2,6-
Diaminotoluene, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylmethane, 3,3 '
-Diaminobenzophenone, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,4 '
-Diaminodiphenyl ether, 1,5-diaminonaphthalene,

2,4-bis (β-amino-t-butyl)
Toluene, bis (p-β-amino-t-butyl-phenyl) ether, bis (p-β-methyl-γ-amino-pentyl) benzene, bis-p- (1,1-dimethyl-5)
-Aminopentyl) benzene, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis {4- (2-aminophenoxy) phenyl} hexafluoropropane, 2,2-bis {4- ( 3-aminophenoxy) phenyl {hexafluoropropane, 2,2-bis} 4-
(4-aminophenoxy) phenyl} hexafluoropropane, 2,2-bis (3-carbamoyl-4-aminophenyl) hexafluoropropane, 2,2-bis {4- (3
-Carbamoyl-4-aminophenoxy) phenyl} hexafluoropropane, 2,2-bis (3-sulfamoyl-4-aminophenyl) hexafluoropropane, 2,
2-bis {4- (3-sulfamoyl-4-aminophenoxy) phenyl} hexafluoropropane, 2,2-
Bis (3-carboxy-4-aminophenyl) hexafluoropropane, 2,2-bis {4- (3-carboxy-
4-aminophenoxy) phenyl @ hexafluoropropane,

1,3-bis [2- {4- (4-aminophenoxy) phenyl} hexafluoroisopropyl] benzene p-bis (3-carboxy-4-aminophenoxy) tetrafluorobenzene, 4,4'-bis (3-carboxy-4-aminophenoxy) octafluorobiphenyl, 4,4′-diaminooctafluorobiphenyl, 1,2-bis (3-carboxy-4-aminophenyl) tetrafluoroethane, 1,3-bis (3 -Carboxy-4-aminophenyl) hexafluoropropane,
1,5-bis (3carboxy-4-aminophenyl) decafluoropentane, diaminobenzotrifluoride, bis (trifluoromethyl) phenylenediamine,
Diaminotetra (trifluoromethyl) benzene, diamino (pentafluoroethyl) benzene, 2,2′-bis (trifluoromethyl) benzidine, 2,2′-bis (trifluoromethyl) -4,4′-diaminodiphenyl ether, Bis (aminophenoxy) di (trifluoromethyl) benzene, bis (aminophenoxy) tetrakis (trifluoromethyl) benzene, bis [(trifluoromethyl) aminophenoxy] benzene, bis [(trifluoromethyl) aminophenoxy] biphenyl, Bis {[(trifluoromethyl) aminophenoxy] phenyl} hexafluoropropanehexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, tetramethylenediamine, Ropi diamine, 3
-Methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine,

2,11-diaminododecane, 1,2-bis (3-aminopropoxy) ethane, 2,2-dimethylpropylenediamine, 3-methoxy-hexamethylenediamine, 2,5-dimethylhexamethylenediamine,
2,5-dimethylheptamethyldiamine, 5-methylnonamethylenediamine, 2,17-diaminoicosadecane, 1,4-diaminocyclohexane, 1,10-diamino-1,10-dimethyldecane, 1,12-diamino Octadecane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-
Diaminodiphenylmethane, 3,3'-dimethoxy-
4,4'-diaminodiphenylmethane, 3,3'diethoxy-4,4'-diaminodiphenylmethane, 3,3 '
-Difluoro-4,4'-diaminodiphenylmethane,
3,3'-dichloro-4,4'diaminodiphenylmethane, 3,3'-dibromo-4,4'-diaminodiphenylmethane, 3,3'-di (trifluoromethyl) -4,
4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenyl ether, 3,3'-
Diisopropyl-4,4'-diaminodiphenylether, 3,3'-dimethoxy-4,4'-diaminodiphenylether, 3,3'-diethoxy-4,4'-diaminodiphenylether, 3,3'-difluoro-4,
4'-diaminodiphenyl ether, 3,3'-dichloro-4,4'-diaminodiphenyl ether, 3,3 '
-Dibromo-4,4'-diaminodiphenyl ether,
3,3′-di (trifluoromethyl) -4,4′-diaminodiphenyl ether,

3,3'-dimethyl-4,4'-diaminodiphenylsulfone, 3,3'-dimethoxy-4,4 '
-Diaminodiphenylsulfone, 3,3'-diethoxy-4,4'-diaminodiphenylsulfone, 3,3'-
Difluoro-4,4'-diaminodiphenyl sulfone,
3,3'-dichloro-4,4'-diaminodiphenylsulfone, 3,3'-dibromo-4,4'-diaminodiphenylsulfone, 3,3'-di (trifluoromethyl)
-4,4'-diaminodiphenylsulfone, 3,3'-
Dimethyl-4,4'-diaminodiphenylpropane,
3,3'-dimethoxy-4,4'-diaminodiphenylpropane, 3,3'-diethoxy-4,4'-diaminodiphenylpropane, 3,3'-difluoro-4,4 '
-Diaminodiphenylpropane, 3,3'-dichloro-
4,4′-diaminodiphenylpropane, 3,3′-dibromo-4,4′-diaminodiphenylpropane,
3'-di (trifluoromethyl) -4,4'-diaminodiphenylpropane, 3,3'-dimethyl-4,4'diaminodiphenyl sulfide, 3,3'-dimethoxy-
4,4 ′ diaminodiphenyl sulfide, 3,3′-diethoxy-4,4′-diaminodiphenyl sulfide,
3,3'-difluoro-4,4'-diaminodiphenyl sulfide, 3,3'-dichloro-4,4'-diaminodiphenyl sulfide, 3,3'-dibutomo-4,4 '
-Diaminodiphenyl sulfide, 3,3'-di (trifluoromethyl) -4,4'-diaminodiphenyl sulfide,

3,3'-dimethyl-4,4'-diaminodiphenylhexafluoropropane, 3,3'-dimethoxy-4,4'-diaminodiphenylhexafluoropropane, 3,3'-diethoxy-4,4 ' -Diaminodiphenylhexafluoropropane, 3,3'-difluoro-
4,4′-diaminodiphenylhexafluoropropane, 3,3′-dichloro-4,4′-diaminodiphenylhexafluoropropane, 3,3′-dibromo-4,
4'-diaminodiphenylhexafluoropropane,
3,3′-di (trifluoromethyl) -4,4′-diaminodiphenylhexafluoropropane, 3,3′-dimethyl-4,4′-diaminobenzophenone, 3,3 ′
-Dimethoxy-4,4'-diaminobenzophenone,
3,3'-diethoxy-4,4'-diaminobenzophenone, 3,3'-difluoro-4,4'-diaminobenzophenone, 3,3'-dichloro-4,4'-diaminobenzophenone, 3,3'- Dibromo-4,4'-diaminobenzophenone, 3,3'-di (trifluoromethyl) -4,4'-diaminobenzophenone, 3,3'-
Dimethylbenzidine, 3,3 ′, 5,5′-tetramethyl-4,4′-diaminodiphenylmethane, 3,3 ′,
5,5′-tetraisopropyl-4,4′-diaminodiphenylmethane, 3,3 ′, 5,5′-tetramethoxy-4,4′-diaminodiphenylmethane, 3,3 ′,
5,5'-tetraethoxy-4,4'-diaminodiphenylmethane, 3,3 ', 5,5'-tetrafluoro-
4,4'-diaminodiphenylmethane, 3,3 ', 5
5'-tetrachloro-4,4'-diaminodiphenylmethane, 3,3 ', 5,5'-tetrabromo-4,4'-
Diaminodiphenylmethane, 3,3 ′, 5,5′-tetra (trifluoromethyl) -4,4′-diaminodiphenylmethane,

3,3 ', 5,5'-tetramethyl-4,
4'-diaminodiphenyl ether, 3,3 ', 5
5'-tetraethyl-4,4'-diaminodiphenyl ether, 3,3 ', 5,5'-tetramethoxy-4,4'
-Diaminodiphenyl ether, 3,3 ', 5,5'-tetraethoxy-4,4'-diaminodiphenyl ether,
3,3 ′, 5,5′-tetrafluoro-4,4′-diaminodiphenyl ether, 3,3 ′, 5,5′-tetrachloro-4,4′-diaminodiphenyl ether, 3,
3 ′, 5,5′-tetrabromo-4,4′-diaminodiphenyl ether, 3,3 ′, 5,5′-tetra (trifluoromethyl) -4,4′-diaminodiphenyl ether, 3,3 ′, 5 5'-tetramethyl-4,4'-
Diaminodiphenyl sulfone, 3,3 ′, 5,5′-tetramethoxy-4,4′-diaminodiphenyl sulfone,
3,3 ', 5,5'-tetraethoxy-4,4'-diaminodiphenylsulfone, 3,3', 5,5'-tetrafluoro-4,4'-diaminodiphenylsulfone, 3,
3 ′, 5,5′-tetrachloro-4,4′-diaminodiphenylsulfone, 3,3 ′, 5,5′-tetrabromo-4,4′-diaminodiphenylsulfone, 3,3 ′,
5,5'-tetra (trifluoromethyl) -4,4'-
Diaminodiphenyl sulfone, 3,3 ′, 5,5′-tetramethyl-4,4′-diaminodiphenylpropane,
3,3 ′, 5,5′-tetramethoxy-4,4′-diaminodiphenylpropane, 3,3 ′, 5,5′-tetraethoxy-4,4′-diaminodiphenylpropane, 3,
3 ′, 5,5′-tetrafluoro-4,4′-diaminodiphenylpropane, 3,3 ′, 5,5′-tetrachloro-4,4′-diaminodiphenylpropane, 3,3 ′,
5,5′-tetrabromo-4,4′-diaminodiphenylpropane, 3,3 ′, 5,5′-tetra (trifluoromethyl) -4,4′-diaminodiphenylpropane,

3,3 ', 5,5'-tetramethyl-4
4'-diaminodiphenyl sulfide, 3,3 ', 5
5'-tetramethoxy-4,4'-diaminodiphenyl sulfide, 3,3 ', 5,5'-tetraethoxy-
4,4′-diaminodiphenyl sulfide, 3,3 ′,
5,5′-tetrafluoro-4,4′-diaminodiphenyl sulfide, 3,3 ′, 5,5′-tetrachloro-
4,4′-diaminodiphenyl sulfide, 3,3 ′,
5,5′-tetrabromo-4,4′-diaminodiphenyl sulfide, 3,3 ′, 5,5′-tetra (trifluoromethyl) -4,4′-diaminodiphenyl sulfide, 3,3 ′, 5,5 '-Tetramethyl-4,4'-diaminodiphenylhexafluoropropane, 3,3',
5,5′-tetramethoxy-4,4′-diaminodiphenylhexafluoropropane, 3,3 ′, 5,5′-tetraethoxy-4,4′-diaminodiphenylhexafluoropropane, 3,3 ′, 5 5′-tetrafluoro-4,4′-diaminodiphenylhexafluoropropane, 3,3 ′, 5,5′-tetrachloro-4,4′-diaminodiphenylhexafluoropropane, 3,3 ′,
5,5′-tetrabromo-4,4′-diaminodiphenylhexafluoropropane, 3,3 ′, 5,5′-tetra (trifluoromethyl) -4,4′-diaminodiphenylhexafluoropropane,

3,3 ', 5,5'-tetramethyl-4,
4'-diaminobenzophenone, 3,3 ', 5,5'-
Tetramethoxy-4,4′-diaminobenzophenone,
3,3 ′, 5,5′-tetraethoxy-4,4′-diaminobenzophenone, 3,3 ′, 5,5′-tetrafluoro-4,4′-diaminobenzophenone, 3,3 ′,
5,5'-tetrachloro-4,4'-diaminobenzophenone, 3,3 ', 5,5'-tetrabromo-4,4'
-Diaminobenzophenone, 3,3 ', 5,5'-tetra (trifluoromethyl) -4,4'-diaminobenzophenone, 3,3', 5,5'-tetraisopropyl-
4,4′-diaminodiphenylmethane, 3,3′-diisopropyl-5,5′-dimethyl-4,4′-diaminodiphenylmethane, 3,3′-diisopropyl-5
5'-diethyl-4,4'-diaminodiphenylmethane, 3,3'-diisopropyl-5,5'-dimethyl-
4,4'-diaminodiphenyl ether, 3,3'-diisopropyl-5,5'-diethyl-4,4'-diaminodiphenyl ether, 3,3'-diisopropyl-
5,5′-dimethyl-4,4′-diaminodiphenylpropane, 3,3′-diisopropyl-5,5′-diethyl-4,4′-diaminodiphenylpropane, 3,3 ′
-Diisopropyl-5,5'-dimethyl-4,4'-diaminodiphenylsulfone, 3,3'-diisopropyl-5,5'-diethyl-4,4'-diaminodiphenylsulfone, 3,3'-bis (tri Fluoromethyl) benzidine, 2,2′-bis (trifluoromethyl) -4,
4'-diaminodiphenyl ether, 3,3'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether, 3,3 ', 5,5'-tetrakis (trifluoromethyl) -4,4'-diaminodiphenyl ether , 3,3'-bis (trifluoromethyl) -4,4 '
-Diaminobenzophenone and the like, and two or more of these may be used in combination. Among these diamines, aromatic diamines are preferred in terms of heat resistance.

As a part of the diamine, silicon diamine may be used. As the silicon diamine, 1,3-bis (3-aminopropyl) -1,1,1
3,3 - tetraphenyl disiloxane, 1,3-bis (3-aminopropyl) -1,1, 3,3 - tetramethyl disiloxane, 1,3-bis (4-aminobutyl) -
1,1, 3,3 - there is tetramethyldisiloxane and the like.
When using silicon diamines, these are preferably used in an amount of 0.1 to 10 mol% based on the total amount of the diamines. By using silicon diamine, the resulting polyimide resin has improved adhesion.

In producing the polyimide resin,
The tetracarboxylic dianhydride and the diamine are reacted at an appropriate temperature. In this reaction, the degree of imidization can be appropriately adjusted by selecting appropriate conditions. For example, to produce a completely or almost completely imidized polyimide by reacting at 100 ° C. or higher, particularly 120 ° C. or higher, if necessary, in the presence of a catalyst such as tributylamine, triethylamine, and triphenyl phosphite. (The catalyst is preferably used in an amount of 0 to 15% by weight based on the total amount of the reaction components, and more preferably 0.1 to 15% by weight.
When the reaction is carried out at 80 ° C. or less, particularly at 50 ° C. or less, it is a precursor of the polyimide and is completely or almost not imidized.
Polyamic acid can be produced. Further, a polyimide precursor in which imidization has partially progressed can be produced.

The polyamic acid or the polyimide precursor partially imidized is further heated at 100 ° C.
Above, particularly a method of imidization by heating to 120 ° C. or higher, acetic anhydride, propionic anhydride, acid anhydrides such as benzoic anhydride, ring-closing agents such as carbodiimides such as dicyclohexylcarbodiimide, and pyridine and isoquinoline as needed. Chemical ring closure (imidization) in the presence of a ring closure catalyst such as trimethylamine, aminopyridine, imidazole, etc.
(Preferably, the ring-closing agent and the ring-closing catalyst are used in a range of 1 to 8 mol per 1 mol of the acid anhydride) to produce a polyimide in which imidation is almost or completely completed. it can. These reactions are preferably performed in the presence of an organic solvent.

Organic polar solvents usable in the above reaction include N, N-dimethylformamide, N, N-
Dimethylacetamide, N-methyl-2-pyrrolidone,
Dimethyl sulfoxide, hexamethylphosphoramide,
There are phenol, m-cresol, chlorobenzene and the like, and two or more kinds thereof may be used as a mixture as long as they are compatible with each other. In addition, along with these organic polar solvents, toluene,
General-purpose solvents such as xylene, cellosolve acetate, and methyl cellosolve can be used in combination as long as the solubility of the polyimide resin or its precursor is not reduced. There is no particular limitation on the order in which the reactants are added.

In the polyimide resin thus obtained, a polyimide precursor, especially a polyamic acid,
It is dissolved in N, N-dimethylacetamide at a concentration of 0.1 g / dl and has a reduced viscosity of 0.1 d when measured at 30 ° C.
It is preferably at least 1 / g. Polyimide can be easily adjusted to have a glass transition temperature of 100 to 250 ° C.

The material for the liquid crystal alignment film contains the above-mentioned polyimide resin, but is preferably a material obtained by dissolving this polyimide resin in an organic solvent (varnish). As the organic solvent, those exemplified above as those which can be used in the production of the polyimide resin can be used. The selection of the organic solvent to be used is determined in consideration of the solubility of the polyimide-based resin. Among the polyimide-based resins, a polyimide precursor such as polyamic acid has good solubility in the organic solvent.

The material for a liquid crystal alignment film is applied on a suitable substrate such as a glass substrate on which a transparent electrode such as ITO (Indium Tin Oxide) is formed in advance, and dried to form a polyimide layer. As a coating method, a dipping method, a printing method, a spraying method, or the like is used. Drying temperature is 10
The temperature is selected in the range of 0 to 250 ° C, preferably 150 to 230 ° C. When a polyimide precursor such as polyamic acid is used as the polyimide resin, the temperature is set to a temperature not lower than the temperature at which ring closure occurs. ℃ or more is preferable,
In particular, 200 ° C. or higher is preferable. The heating time is 1 minute to 6 minutes.
The time is preferred, especially 1 minute to 3 hours. In order to improve the adhesion between the substrate and the polyimide layer, a coupling agent such as a silane coupling agent or a titanium coupling agent may be used between them.

The polyimide layer thus formed is used as a liquid crystal alignment film by rubbing the surface. A liquid crystal display device can be obtained by a known method using the liquid crystal holding substrate having the liquid crystal alignment film.

The liquid crystal alignment film is particularly suitable for an STN type liquid crystal display device having a twist angle of 240 to 270 °. Further, those containing the structural unit represented by the general formula (II) in the molecular structure are particularly suitable for an active twisted nematic liquid crystal display device.

[0041]

EXAMPLES The present invention will be described below with reference to examples, but the scope of the present invention is not limited by these examples.

Synthesis Example 1 A four-necked flask equipped with a thermometer, a stirrer, a nitrogen inlet tube, a drying tube and a nitrogen inlet tube was charged with 8 g of N, N-dimethylacetamide and 0.4 g of 4,4'-diaminodiphenyl ether. 20 g (2 mmol) were added and stirred until a homogeneous solution was obtained. After the diamine was dissolved, 0.82 g (2 mmol) of ethylene glycol bis (trimellitic anhydride) was added little by little. After completion of the addition, the mixture was stirred for 5 hours while being cooled in an ice bath, and reacted to obtain a polyamic acid solution.

Synthesis Example 2 N, N-dimethylformamide (8 g, 2,2) was placed in a four-necked flask equipped with a thermometer, a stirrer, a drying tube and a nitrogen inlet tube.
0.45 g of 2-bis (4-aminophenyl) propane
(2 mmol) and stirred until a homogeneous solution was obtained.
After the diamine was dissolved, 0.99 g (2 mmol) of 1,8-octanediol bis (trimellitic anhydride) was added little by little. After the addition, cool in an ice bath for 2 hours.
After that, the reaction was performed at room temperature for 3 hours to obtain a polyamic acid solution.

Synthesis Example 3 N, N-dimethylacetamide (8 g, 2,2) was placed in a four-necked flask equipped with a thermometer, a stirrer, a drying tube and a nitrogen inlet tube.
0.23 g of 2-bis (4aminophenyl) propane (1
Mmol), 4,4'-diaminodiphenylmethane.
20 g (1 mmol) was added and stirred until a homogeneous solution was obtained. After the diamine is dissolved, 1,10-decandio-
A mixture of 0.522 g (1 mmol) of rubis (trimellitic anhydride) and 0.29 g (1 mmol) of 3,3 ', 4,4'-diphenyltetracarboxylic dianhydride was added little by little. After completion of the addition, the mixture was reacted at room temperature for 5 hours to obtain a polyamic acid solution.

Synthesis Example 4 In Synthesis Example 2, instead of 0.99 g (2 mmol) of 1,8-octanediol bis (trimellitic anhydride), 3,3 ′, 4,4′-benzophenonetetracarboxylic acid dicarboxylic acid was used. A polyamic acid solution was obtained according to Synthesis Example 2, except that 0.64 g (2 mmol) of anhydride was used.

Synthesis Example 5 8 g of N, N-dimethylacetamide and 0.40 g of 4,4'-diaminodiphenyl ether (2 g) were placed in a four-necked flask equipped with a thermometer, a stirrer, a drying tube and a nitrogen inlet tube.
Mmol) and stirred until a homogeneous solution was obtained. After the diamine was dissolved, 0.52 g (1 mmol) of 1,10-decandioyl bis (trimellitic anhydride) was added to 1,1
A mixture of 0.22 g (1 mmol) of 2,4,5-cyclohexanetetracarboxylic dianhydride was added in small portions. After the addition is completed, the mixture is reacted for 5 hours while cooling in an ice bath,
A solution of the polyamic acid was obtained.

Synthesis Example 6 In a four-necked flask equipped with a thermometer, a stirrer, a drying tube and a nitrogen introducing tube, 8 g of N-methyl-2-pyrrolidone and
0.45 g of 2-bis (4-aminophenyl) propane
(2 mmol) and stirred until a homogeneous solution was obtained.
After dissolution of the diamine, 0.84 g (1.6 mmol) of 1,10-decandioylbis (trimellitic anhydride) and 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 0. 08 g (0.4 mmol) of the mixture were added in small portions. After completion of the addition, the mixture was reacted at room temperature for 5 hours to obtain a polyamic acid solution.

Synthesis Example 7 N, N-dimethylformamide (8 g, 2,2) was placed in a four-necked flask equipped with a thermometer, a stirrer, a drying tube and a nitrogen inlet tube.
0.27 g of 2-bis (4-aminophenyl) propane
(1.2 mmol) and 0.16 g (0.8 mmol) of 4,4'-diaminodiphenylmethane were stirred and stirred until a homogeneous solution was obtained. After the diamine is dissolved, 0.35 of 1,5-pentanedioylbis (trimellitic anhydride)
g (0.8 mmol) and 3,3 ', 4,4'-dicyclohexyltetracarboxylic dianhydride, 0.39 g (1.
2 mmol) was added in small portions. After completion of the addition, the mixture was reacted at room temperature for 5 hours to obtain a polyamic acid solution.

Synthesis Example 8 N, N-dimethylacetamide (8 g) and 4,4'-diaminodiphenyl ether (0.40 g) were placed in a four-necked flask equipped with a thermometer, a stirrer, a drying tube and a nitrogen inlet tube.
(2.0 mmol) and stirred until a homogeneous solution was obtained. After the diamine is dissolved, 0.42 g (0.8 mmol) of decandiol (bistrimellitic anhydride),
0.20 g (1.0 mmol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 3,3 ′, 4
4'-benzophenonetetracarboxylic dianhydride 0.0
6 g (0.2 mmol) of the mixture were added in small portions.
After completion of the addition, the mixture was reacted for 5 hours while cooling in an ice bath to obtain a polyamic acid solution.

Synthesis Example 9 In Synthesis Example 5, 0.52 g (1 mmol) of 1,10-decandioyl bis (trimellitic anhydride) and 0.1% of 1,2,4,5-cyclohexanetetracarboxylic dianhydride were added. 3,3 ', instead of 22g (1mmol)
4,4'-benzophentetracarboxylic dianhydride
A polyamic acid solution was obtained according to Synthesis Example 5 except that 64 g (2 mmol) was used.

Synthesis Example 10 In Synthesis Example 6, 0.84 g (1.6 mmol) of 1,10-decandioyl bis (trimellitic anhydride) and 1,2,3,4-cyclopentanetetracarboxylic dianhydride Instead of 0.08 g (0.4 mmol)
A polyamic acid solution was obtained according to Synthesis Example 6, except that only 0.42 g (2.0 mmol) of 2,3,4-cyclopentanetetracarboxylic dianhydride was used.

Synthesis Example 11 In a four-necked flask equipped with a thermometer, a stirrer, a nitrogen inlet tube, a drying tube and a nitrogen inlet tube, 9 g of N, N-dimethylacetamide and 1.08 g of p-phenylenediamine (10
Mmol) and stirred until a homogeneous solution was obtained. Thereafter, a mixture of 0.99 g (5 mmol) of butane-1,2,3,4-tetracarboxylic dianhydride and 2.47 g (5 mmol) of octanediol (bistrimellitic anhydride) was added little by little. After completion of the addition, the reaction was carried out at room temperature for 5 hours to obtain a polyamic acid solution.

Synthesis Example 12 1.78 g (9 mmol) of butane-1,2,3,4-tetracarboxylic dianhydride was used, and decanediol (bistrimellitic anhydride) was used instead of octanediol (bistrimellitic anhydride). A polyamic acid was obtained in the same manner as in Synthesis Example 11 except that 0.52 g (1 mmol) of acid anhydride was used.

Table 1 shows the measurement results of the reduced viscosities of the polyamic acids obtained in Synthesis Examples 1 to 12. In addition, a solution of these polyamic acids is applied on a glass substrate by spin coating, and is applied at 150 ° C., 200 ° C., 250 ° C., and 300 ° C.
For 30 minutes each to produce a polyimide film. Table 1 shows the results of measuring the glass transition temperature of polyimide using these polyimide films. Incidentally, the reduced viscosity of the polyamic acid, the solution of the polyamide obtained in each synthesis example is poured into water or methanol,
The precipitated polyamic acid is filtered off and dried, and then N, N-
It was dissolved in dimethylacetamide at a concentration of 0.1 g / dl and measured at 30 ° C. The glass transition temperature of the polyimide was measured using a DSC-7 model manufactured by PerkinElmer, Inc. at a rate of temperature increase of 10 ° C./min and a sample amount of about 10 mg.

[0055]

[Table 1]

Examples 1 to 9 and Comparative Examples 1 to 3 The polyamic acid solutions obtained in Synthesis Examples 1 to 12 were
-Diluted with dimethylacetamide to a solid content of about 5% by weight to prepare a composition for a liquid crystal alignment film. This solution was spin-coated on two glass substrates with ITO transparent electrodes. Thereafter, the resultant was separately heated and dried at 180 ° C., 230 ° C., or 250 ° C. for 1 hour to form a polyimide layer having a thickness of 500 °. Next, the surface of the polyimide layer is rubbed to obtain a liquid crystal holding substrate. The two substrates are combined with the polyimide layers facing each other so that the rubbing directions are antiparallel.
00 (Hitachi Chemical Industry Co., Ltd.), 120
A test liquid crystal display cell was assembled by performing heat curing at 2 ° C. for 2 hours. These test liquid crystal display cells were filled with liquid crystal Z at room temperature.
LI-1132 (trade name, manufactured by Merck) was sealed to form a liquid crystal cell. After heating the liquid crystal at 120 ° C., which is a temperature not _lower than T _NI (71 ° C.), for 1 hour, the pretilt angle of the cell was measured using a laser beam. Table 2 shows the results of measurement together with the polyamic acid used (synthesis example for producing the same).

[Table 2]

Using the liquid crystal display cells obtained in Examples 4 to 9 and Comparative Examples 2 to 3, the voltage holding ratio was measured. In Table 3,
The measurement results are shown together with the used polyamic acid (synthesis example for producing the same). The voltage holding ratio was measured as follows. The drain of the TFT element is electrically connected to the ITO electrode on one substrate of the liquid crystal display cell, the ITO electrode on the other substrate of the liquid crystal display cell is grounded, and the pulse width is applied between the gate and the source of the TFT element. A gate signal of 100 μs and a source signal having a frequency of 30 Hz and a voltage of ± 4.5 V were input, and a change in drain voltage was measured. The measurement was performed by monitoring with a digital memory scope. {[(Drain voltage value at rising of source signal)-(Value of applied drain voltage at falling of source signal)] / (Drain voltage value at rising of source signal)} × 100
(%) Was determined as the voltage holding ratio.

[Table 3]

Next, using the polyamic acid solution (composition for liquid crystal alignment film) obtained in Synthesis Examples 1 to 3 and Synthesis Examples 5 to 7 to obtain 640 × 200 dots in the same manner as described above. A polyimide layer is formed on the substrate on which the ITO transparent electrode is formed, the surface of this layer is subjected to a rubbing treatment, and a cell is assembled in the same manner as described above so that the liquid crystal becomes a twist of 240 °. A liquid crystal prepared by adding 811 (manufactured by Merck) was sealed, and heated at 120 ° C. for 1 hour to form a liquid crystal display device. Each of the obtained liquid crystal display devices could be driven at 640 × 200 dots, and had high display quality without occurrence of domain and other alignment defects.

[0059]

According to the liquid crystal alignment film of the present invention, a high pretilt angle can be stably obtained even when the liquid crystal alignment film is cured at a relatively low temperature. The liquid crystal holding substrate according to the third aspect can also exhibit an excellent pretilt angle. The liquid crystal display element of the fourth aspect also exhibits an excellent pretilt angle. The liquid crystal alignment film according to claim 1 can be obtained from the liquid crystal alignment film material according to claims 5 and 7, and the liquid crystal alignment film according to claim 2 can be obtained from the liquid crystal alignment film material according to claims 6 and 8. be able to.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuo Miyadera 48, Wadai, Tsukuba, Ibaraki Hitachi Chemical Co., Ltd. Tsukuba Research Laboratory (72) Inventor Masahiro Kawakami 4-13-1, Higashicho, Hitachi, Ibaraki Hitachi (56) References JP-A-63-106729 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02F 1/1337

Claims (5)

(57) [Claims] (1) a structural unit represented by the general formula (I): [In the general formula (I), n represents an integer of 2 to 16, and R represents a divalent organic group. ] And (b) of 2 [formula (II)] [Chemical Formula 2] [However, in the general formula (II), A is a tetracyclic compound having an alicyclic structure.
The tetravalent residue of lacarboxylic dianhydride, R 'is a divalent organic
Represents a group. ] The liquid crystal alignment film containing the polyimide containing the structural unit represented by these . 2. A liquid crystal holding substrate in which a pair of electrode substrates having the liquid crystal alignment film according to claim 1 formed on one surface of the substrate are opposed to each other, and a liquid crystal is held between the electrode substrates. 3. A liquid crystal display device having the liquid crystal holding substrate according to claim 2. 4. A structural unit represented by the following formula (a): ## STR3 ## [However, in the general formula (I ′), n is an integer of 2 to 16,
Represents a divalent organic group. ] And (b) of 4 [formula (II ')] embedded image [However, in the general formula (II '), A and R' represent the general formula (I
Same as I). And a polyamic acid comprising a structural unit represented by the formula: 5. (a) Tetracarboxylic dianhydride represented by the general formula (IV): ## STR5 ## [However, in general formula (IV), n shows the integer of 2-16. ] And (b) of 6 [Formula (V)] embedded image [However, in the general formula (V), A is a tetracyclic compound having an alicyclic structure.
Shows the tetravalent residue of lacarboxylic dianhydride. ]
A liquid crystal alignment film material including a polyimide resin, obtained by reacting a diamine compound in an acid component comprising a tetracarboxylic dianhydride that.