JP2993221B2 - Liquid crystal alignment film, liquid crystal holding substrate and liquid crystal display device 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 Application Laid-Open No. Sho 62-174725, U.S. Pat. 492), (2) a method of adding an amine compound having a long-chain fluoroalkyl group to polyimide (JP-A-1-180518), (3) a method of adding a metal complex having a long-chain fluoroalkyl group (Proceedings of the 13th Liquid Crystal Symposium 1987
October). However, any of these methods has a disadvantage that a stable pretilt angle cannot be obtained. Also, JP-A-62-207332 discloses that
Although a fluorine-containing polybenzoxazole represented by the following formula (5) is disclosed, a stable pretilt angle cannot be obtained as a liquid crystal alignment film.

Embedded image (Wherein, R ⁶ represents a divalent aromatic group).

[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, a liquid crystal holding substrate, a liquid crystal display element and a liquid crystal alignment film having the same. To provide a composition for use.

[0004]

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

Embedded image [However, in the general formula (I), Rf is -C _n F _2n-1 (where, n represents a is 6-12 integer) indicates the hydrogen of the benzene ring may be substituted, X is A tetravalent organic group containing an aromatic ring, wherein two sets of N and O are respectively bonded to the aromatic ring in X at the ortho position so as to form a five-membered ring] It contains fluorine-containing polybenzoxazole.

In the general formula (I), examples of the substituent which may be bonded to the benzene ring include a lower alkyl group, a lower alkoxy group, fluorine, chlorine and bromine.

The above-mentioned fluorine-containing polybenzoxazole is further represented by the general formula (I).

Embedded image [However, in the general formula (I ′), Z is a compound represented by the following general formula (I):

Embedded image And X 'is a tetravalent organic group containing an aromatic ring, and two sets of N and O represent an aromatic group in X' so as to form a five-membered ring, respectively. To the ring at the ortho position to each other].

The fluorine-containing polybenzoxazole is
It is preferable that the structural unit represented by the general formula (I) and the structural unit represented by the general formula (I ′) are contained so that the molar ratio of the latter / the former is 0/100 to 95/5,
In particular, it is preferable to include it so as to be 0/100 to 90/10. The fluorine-containing polyimide having a small number of structural units represented by the general formula (I) tends to have a low pretilt angle.

The liquid crystal alignment film is formed of ITO (Indium Tin Oxi).
The liquid crystal holding substrate having the liquid crystal alignment film can be formed on an appropriate substrate such as a glass substrate on which a transparent electrode such as de) is formed.

An electrode is provided by a known method using the above-mentioned liquid crystal holding substrate, and the liquid crystal has a liquid crystal holding substrate on which the liquid crystal alignment film is provided facing the liquid crystal. It can be a display element.

The liquid crystal alignment film can be prepared by using a liquid crystal alignment film material containing a fluorine-containing polyhydroxyamide which is a precursor of a fluorine-containing polybenzoxazole. Fluorine-containing polyhydroxyamide is
[General formula (II)]

Embedded image [However, in the general formula (II), Rf and X are the same as those in the general formula (II), and the hydrogen of the benzene ring may be substituted with a lower alkyl group, a lower alkoxy group or a halogen; OH is bonded to the aromatic ring in X at the ortho-position to each other].

The above-mentioned fluorine-containing polyhydroxyamide is represented by the general formula (II):
[General formula (II ')]

Embedded image [However, in the general formula (II '), Z and X' are the same as in the general formula (I '), and two sets of NH and OH are each represented by X
Are bonded to the aromatic ring at the ortho position to each other.] In this case, it is preferable to contain 5 to 100 mol% of the structural unit represented by the general formula (II) and 95 to 0 mol% of the structural unit represented by the general formula (II ′).

The liquid crystal alignment film can be manufactured using a liquid crystal alignment film material containing a polybenzoxazole-based resin described below.

The polybenzoxazole-based resin is represented by the following general formula (III):

Embedded image [However, in the general formula (III), Rf is -C _n F _2n-1 (where, n represents a is 6-12 integer) indicates the hydrogen of the benzene ring may be substituted] represented by And an acid component containing an aromatic dicarboxylic acid or an amide-forming derivative thereof represented by the general formula (IV):

Embedded image [Wherein, in the general formula (IV), R ¹ , R ² , R ³ and R ⁴ each independently represent hydrogen or a trialkylsilyl group, X represents a tetravalent organic group containing an aromatic ring, -NH-
R ¹ and —O—R ³ and —NH—R ² and —O—R ⁴ are each bonded to the aromatic ring in X at the ortho position.] It can be obtained by reacting a phenol component.

In this method, an aromatic dicarboxylic acid represented by the general formula (III) or an amide-forming derivative thereof is used as an acid component, and a bis (aminophenol) compound represented by the general formula (IV) is used as a reaction partner ( An aminophenol component) and a condensation or condensation / ring-closure reaction thereof. As the acid component, a dicarboxylic acid or an amide thereof reactive with the aminophenol component in addition to the aromatic dicarboxylic acid or an amide-forming derivative thereof. A forming derivative may be used in combination.

Examples of the dicarboxylic acid compound represented by the general formula (III) include 5- (perfluorononenyloxy) isophthalic acid, 4- (perfluorononenyloxy) phthalic acid, and 2- (perfluorononenyloxy) Terephthalic acid, 4-methyl-5- (perfluorononenyloxy) isophthalic acid, 4-methoxy-5- (perfluorononenyloxy) isophthalic acid, 2,4,6-trifluoro-5- (perfluorononene Nyloxy) isophthalic acid, 4-chloro-5- (perfluorononenyloxy) isophthalic acid, 4-bromo-5- (perfluorononenyloxy) isophthalic acid, 4-methyl-5- (perfluorononenyloxy) ) Phthalic acid, 4-methoxy-5
-(Perfluorononenyl) phthalic acid, 3,4,6-trifluoro-5- (perfluorononenyloxy) phthalic acid, 4-chloro-5- (perfluorononenyloxy) phthalic acid, 4-bromo -5- (perfluorononenyloxy) phthalic acid, 2-methyl-5- (perfluorononenyloxy) terephthalic acid, 4-methoxy-5-
(Perfluorononenyloxy) terephthalic acid, 2,
3,6-trifluoro-5- (perfluorononenyloxy) terephthalic acid, 2-chloro-5- (perfluorononenyloxy) terephthalic acid, 2-bromo-5- (perfluorononenyloxy) terephthalic acid 5- (perfluorohexenyloxy) isophthalic acid, 4- (perfluorohexenyloxy) phthalic acid, 2- (perfluorohexenyloxy) terephthalic acid, 4-methyl-5
-(Perfluorohexenyloxy) isophthalic acid, 4
-Methoxy-5- (perfluorohexenyloxy) isophthalic acid, 2,4,6-trifluoro-5- (perfluorohexenyloxy) isophthalic acid, 4-chloro-
5- (perfluorohexenyloxy) isophthalic acid,
4-bromo-5- (perfluorohexenyloxy) isophthalic acid, 4-methyl-5- (perfluorohexenyloxy) phthalic acid, 4-methoxy-5- (perfluorohexenyloxy) phthalic acid, 3,4,6 -Trifluoro-5- (perfluorohexenyloxy) phthalic acid, 4-chloro-5- (perfluorohexenyloxy) phthalic acid, 4-bromo-5- (perfluorohexenyloxy) phthalic acid, 2-methyl-5 -(Perfluorohexenyloxy) terephthalic acid, 4-methoxy-5
-(Perfluorohexenyloxy) terephthalic acid,
2,3,6-trifluoro-5- (perfluorohexenyloxy) terephthalic acid, 2-chloro-5- (perfluorohexenyloxy) terephthalic acid, 2-bromo-
5- (perfluorohexenyloxy) terephthalic acid and the like.

As the perfluorononenyl group, for example, a compound represented by the following formula (A):

Embedded image And the perfluorohexenyl group is, for example, a compound represented by the following formula (B):

Embedded image There is a group.

Among the aromatic dicarboxylic acids represented by the general formula (III), perfluoroalkenyloxyisophthalic acid can be produced, for example, by producing p-perfluoroalkenyloxybenzoic acid described in JP-A-60-511146. It can be prepared according to the law. For example, 5
-Hydroxyisophthalic acid can be prepared by reacting a dimer or trimer of hexafluoropropene in the presence of an excess of an amine, the others likewise corresponding to the corresponding dicarboxylic acid and perfluoro It can be manufactured using alkenes.

The dicarboxylic acid represented by the above general formula (III) is described in, for example, JP-A-50-12124.
According to the method described in JP-A No. 3 (1993) -3, an oligomer of an ester of hydroxy-dicarboxybenzene such as diphenyl ester or dibenzyl ester and an oligomer of a fluoroalkene such as fluoropropene trimer or tetrafluoroethylene pentamer is used as a proton acceptor. In an aprotic organic solvent in the presence of
After reacting at or below room temperature in the presence of a base catalyst, the reaction product is isolated, and the reaction product is hydrolyzed in the presence of a basic compound such as sodium hydroxide, potassium hydroxide, and the like. It can be produced by appropriately treating with an acid such as hydrochloric acid. The reaction product and the final product are appropriately purified by means such as washing and recrystallization.

The amide-forming derivative of the aromatic dicarboxylic acid represented by the general formula (III) is a derivative capable of forming an amide bond by reacting with the bis (aminophenol) represented by the general formula (IV). There are acid halides such as dichloride and dibromide of the above aromatic dicarboxylic acid, and dialkyl esters such as dimethyl ester and diethyl ester of the acid.

The dichloride is, for example, represented by the general formula (I)
The compound can be obtained in high yield by reacting the aromatic dicarboxylic acid represented by II) with thionyl chloride.

The above-mentioned dialkyl esters such as dimethyl ester and diethyl ester can be prepared by converting an alcohol such as methanol or ethanol into a compound of the formula (III) in the presence of an acid.
By reacting with an aromatic dicarboxylic acid represented by the formula:

The dicarboxylic acid or the amide-forming derivative thereof which may be used in combination with the aromatic dicarboxylic acid or the amide-forming derivative thereof represented by the general formula (III) is represented by the following formula (III).

Embedded image [However, in the general formula (III '), Z is the general formula (I')
Is the same as the above), or a amide-forming derivative thereof, wherein Z in the general formula (III ′) is
Dicarboxylic acid, which is a divalent organic group containing an aromatic ring, or an amide-forming derivative thereof is preferable in view of heat resistance of the obtained polymer. As the divalent organic group containing an aromatic ring,
[General formula (a)]

Embedded image A group represented by the general formula (b):

Embedded image [Where Z 'is a bond, -O-, -S-, -SO
_{2 -, - C (= O} ) -, - CH 2 -, - C (CH 3) 2 -,
—CF ₂ —, —C (CF ₃ ) ₂ —, etc.];

Embedded image (Where Z 'is the same as above, and two Z's
May be the same or different) or a group represented by the general formula (d):

Embedded image (Where Z 'is the same as above and three Z's
May be the same or different), and these groups may be appropriately substituted with a lower alkyl group, a lower alkoxy group, halogen such as chlorine, bromine, and fluorine. . These groups are also Z in general formulas (I ') and (II').

Examples of the dicarboxylic acids represented by the general formula (III ') include aliphatic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid. Dicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, 3,3'-dicarboxylic diphenyl ether, 3,4'-dicarboxylic diphenyl ether, 4,4'-dicarboxylic diphenyl ether, 3,3'- Dicarboxyldiphenylmethane, 3,4'-dicarboxyldiphenylmethane,
4,4'-dicarboxyldiphenylmethane, 3,3 '
-Dicarboxyldiphenyldifluoromethane, 3,
4'-dicarboxyldiphenyldifluoromethane,
4,4'-dicarboxyldiphenyldifluoromethane, 3,3'-dicarboxyldiphenylsulfone,
3,4'-dicarboxyldiphenylsulfone 4,4 '
Dicarboxylic diphenyl sulfone, 3,3'-dicarboxyl diphenyl sulfide, 3,4'-dicarboxyl diphenyl sulfide, 4,4'-dicarboxyl diphenyl sulfide, 3,3 ' -Dicarboxylic diphenyl ketone, 3,4'-dicarboxylic diphenyl ketone, 4,4'-dicarboxylic diphenyl ketone,
2,2-bis (3-carboxylphenyl) propane,
22- (3,4'-dicarboxylphenyl) propane, 2,2-bis (4-carboxylphenyl) propane, 2,2-bis (3-carboxylphenyl) hexafluoropropane, 2,2- ( 3,4'-dicarboxylphenyl) hexafluoropropane, 2,2-bis (4-carboxylphenyl) hexafluoropropane, 1,3-bis (3-carboxylphenoxy) benzene, 1,4-bis (3-carboxylphenoxy) benzene, 1,4-bis (4-carboxylphenoxy)
Benzene, 3,3 '-(1,4-phenylenebis (1-
Methylethylidene)) bisbenzoic acid, 3,4 '-(1,
4-phenylenebis (1-methylethylidene)) bisbenzoic acid, 4,4 '-(1,4-phenylenebis (1-methylethylidene)) bisbenzoic acid, 2,2-bis (4-
(3-carboxylphenoxy) phenyl) propane,
2,2-bis (4- (4-carboxylphenoxy) phenyl) propane, 2,2-bis (4- (3-carboxylphenoxy) phenyl) hexafluoropropane,
2,2-bis (4- (4-carboxylphenoxy) phenyl) hexafluoropropane, bis (4- (3-carboxylphenoxy) phenyl) sulfide, bis (4- (4-carboxylphenoxy) phenyl) There are aromatic dicarboxylic acids such as phenyl) sulfide, bis (4- (3-carboxylphenoxy) phenyl) sulfone and bis (4- (4-carboxylphenoxy) phenyl) sulfone.

Examples of the amide-forming derivative of the dicarboxylic acid represented by the general formula (III ') include acid halides of the dicarboxylic acid such as dichloride and dibromide.
Examples of the dicarboxylic acid include dialkyl esters such as dimethyl ester and diethyl ester.

As the acid component, an aromatic dicarboxylic acid represented by the general formula (III) or an amide-forming derivative thereof is used in an amount of 5 to 100 mol%, especially 10 to 100 mol%.
It is preferred to use mol%.

Among the bis (aminophenol) compounds represented by the general formula (IV), trialkylsilylated diamines in which R ¹ , R ² , R ³ , and R ⁴ are represented by trialkylsilyl groups are macromolecular compounds. (Macromolec
ules) 21, 3305 (1988) 3,3'-bis (trimethylsiloxy)-as shown below.
It can be adjusted in accordance with the production method of 4,4'-bis (trimethylsilylamino) biphenyl. For example,
Reacting a trialkylsilyl chloride in a tetrahydrofuran solution of 4,4'-diamino-3,3'-dihydroxybiphenyl in the presence of triethylamine,
3,3'-bis (trialkylsiloxy) -4,4'-
Bis (trialkylsilylamino) biphenyl can be obtained.

As the bis (aminophenol) compound represented by the general formula (IV), a compound in which at least R ¹ and R ² are a trialkylsilyl group in order to obtain a higher molecular weight benzoxazole-based polymer. preferable.
As the trialkylsilyl group, a trimethylsilyl group,
There are a triethylsilyl group and a tripropylsilyl group.

X in the general formula (IV) is, for example,

Embedded image A group represented by the general formula (b)

Embedded image [Wherein, Y is a bond, -O-, -S-, -SO ₂
-, - C -, - CH 2 -, - C (CH 3) 2 -, - CF
_2- , -C (CF ₃ ) ₂ -or -Rf '-(ORf') _m-
Wherein Rf ′ represents a divalent fluorocarbon, n is an integer of 1 to 5, and a plurality of Rf ′s may be the same or different. c ')]

Embedded image [Wherein, Y is the same as general formula (b '), and 2
Y may be the same or different], or a group represented by the general formula (d ')

Embedded image [Wherein, Y is the same as general formula (b ′), and 3
Y may be the same or different], and the benzene ring in these groups may be appropriately substituted with a lower alkyl group, a lower alkoxy group, a halogen, or the like. These groups are also X or X 'in general formulas (I), (I'), (II) and (II ').

As the bis (aminophenol) compound represented by the general formula (IV), 3,4-diamino-1,5
-Benzenediol, 3,3'-dihydroxyl-4,
4'-diaminobiphenyl, 3,3'-diamino-4,
4'-dihydroxybiphenyl, 2,2'-bis (3-
Amino-4-hydroxyphenyl) ketone, 2,2-bis (3-amino-4-hydroxyphenyl) sulfide, 2,2-bis (3-amino-4-hydroxyphenyl) ether, 2,2- Bis (3-hydroxy-4-aminophenyl) sulfone, 2,2-bis (3-amino-
4-hydroxyphenyl) propane, 2,2-bis (3
-Hydroxy-4-aminophenyl) propane, 2,2
-Bis (3-hydroxy-4-aminophenyl) methane, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, 2,2-bis (3-hydroxy-4-aminophenyl) hexafluoropropane 2,2-bis (3-amino-4-hydroxyphenyl) difluoromethane,
And trialkylsilyl compounds thereof.

Embedded image

Embedded image

Embedded image

Embedded image

The acid component and the aminophenol component are reacted at an appropriate temperature to obtain a fluorine-containing polybenzoxazole and a fluorine-containing polyhydroxyamide (including those in which the hydroxyl group is trialkylsilylated as described above). The same applies hereinafter). In this reaction, the degree of ring closure can be appropriately adjusted by selecting appropriate conditions. For example, a method in which the acid component and the aminophenol component are melted (preferably at a temperature of 200 ° C. or higher) and reacted without a solvent,
By reacting the acid component and the aminophenol component in an organic solvent or polyphosphoric acid at 150 ° C. or higher, almost or completely closed-ring polybenzoxazole can be produced, and the acid component (sometimes dihalide) and the Aminophenol component in an organic solvent, 80 ° C or less,
In particular, by reacting at 50 ° C. or lower, a polyhydroxyamide which is a precursor of polybenzoxazole and has little or no ring closure can be produced.

The polybenzoxazole precursor (the above-mentioned polyhydroxyamide or the polyhydroxyamide in which ring-closure is partially advanced) is further heated to 100 ° C.
Acetic anhydride, propionic anhydride as required at 50 ° C or higher,
An acid anhydride such as benzoic anhydride, a ring-closing agent such as carbodiimide such as dicyclohexylcarbodiimide, and, if necessary, a ring-closing catalyst such as pyridine, isoquinoline, trimethylamine, aminopyridine, imidazole and the like are added to chemically close the ring (ring closing agent and Each of the ring-closing catalysts has an acid component
It is preferable to use within a range of 1 to 8 moles per mole), so that a polybenzoxazole in which ring closure is almost or completely completed can be produced. These reactions are
Preferably, the reaction is performed in the presence of an organic solvent.

Examples of the organic solvent which can be used in the above include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, hexamethylphosphoramide, phenol, m-cresol, and chlorol. There is an organic polar solvent such as benzene, and two or more kinds may be used as a mixture as long as they are compatible with each other. A general-purpose solvent such as toluene, xylene, cellosolve acetate, or methyl cellosolve can be used together with these organic polar solvents as long as the solubility of polybenzoxazole or its precursor is not reduced.

In any of the above reactions, when dihalide is used as the acid component, the reaction can be appropriately carried out in the presence of a hydrogen halide trapping agent. Examples of the hydrogen halide trapping agent include tertiary amines such as pyridine, triethylamine and dimethylaniline.

The reaction between the acid component and the bis (aminophenol) component is preferably carried out in an equimolar or almost equimolar manner, and the order of addition of each component is arbitrary.

In the above reaction, the group —NH—R ¹ or —NH—R ² of the bis (aminophenol) compound represented by the formula (10) takes precedence over the group —OR ³ or the group —OR ⁴ . And react.

As the bis (aminophenol) compound represented by the general formula (IV), R ³ or R ⁴
Is a trialkylsilyl group, and a precursor of a fluorine-containing polybenzoxazole is produced by the method described above, the resulting polymer is represented by the following formula, in which at least one of the OH groups is a trialkylsiloxy group. Although containing a certain structural unit, this polymer can convert a trialkylsiloxy group into an OH group by adding the reaction solution as it is or by isolating it to methanol or water.

The above-mentioned benzoxazole-based resins such as fluorine-containing polybenzoxazole and fluorine-containing polyhydroxyamide are dimethylacetamide (DMA), respectively.
Those dissolved in c) are dissolved in the solvent at a concentration of 0.1 g / dl, and the reduced viscosity measured at 30 ° C. is 0.01 dl / d.
g or more, particularly preferably 0.3 dl / g or more.
The polyhydroxyamide dissolves in DMAc.

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

The material for a liquid crystal alignment film is applied on an appropriate 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 polybenzoxazole layer. . As a coating method, a dipping method, a printing method, a spraying method, or the like is used.
The drying temperature is 60-350 ° C, preferably 100-300.
Although it is selected in the range of ° C., when a precursor of polybenzoxazole such as polyhydroxyamidic acid is used as the polybenzoxazole-based resin, the temperature is not lower than the temperature at which ring closure occurs. For this purpose, 200 ° C. or higher is preferable. . The heating time is 1 minute to 6 hours, preferably 1 minute to 3 hours. In order to improve the adhesion between the substrate and the polybenzoxazole layer, a coupling agent such as a silane coupling agent or a titanium coupling agent may be used between them.

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

The liquid crystal alignment film is particularly suitable for an STN mode liquid crystal display device having a twist angle of 240 to 270 °.

[0042]

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. 5- (Perfluorononenyloxy) isophthalic acid dichloride used in the following was
8 compound.

Embedded image

Synthesis Example 1 In a reaction vessel equipped with a stirring device, a nitrogen introducing tube, and a drying tube, 2.16 g (0.01 mol) of 3,3'-dihydroxy-4,4'-diaminobiphenyl and 1.1 of pyridine. 74g
(0.022 mol) and 12.3 g of dimethylacetamide were cooled in an ice-water bath. 3,3'-dihydroxy-4,
When 4'-diaminobiphenyl is dissolved, 6.49-perfluorononenyloxyisophthalic acid dichloride is obtained.
g (0.01 mol) are added in small portions. After stirring for 5 hours, the reaction solution was poured into a large amount of methanol to precipitate the polymer. The precipitated polymer was separated by filtration, washed with methanol, and dried to obtain polyhydroxyamide.

Synthesis Example 2 3.66 g (0.01 mol) of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane was placed in a reaction vessel equipped with a stirring device, a nitrogen introducing tube, and a drying tube. , 1.74 g (0.022 mol) of pyridine and 15.2 g of dimethylacetamide were cooled in an ice-water bath. 2,2
When bis- (3-amino-4-hydroxy) hexafluoropropane is dissolved, 6.49 g (0.01 mol) of 5-perfluorononenyloxyisophthalic acid dichloride is obtained.
Is added in small portions. After stirring for 5 hours, the reaction solution was poured into a large amount of methanol to precipitate the polymer. The precipitated polymer is separated by filtration and washed with methanol.
Drying was performed to obtain polyhydroxyamide.

Synthesis Example 3 2.16 g (0.01 mol) of 3,3'-dihydroxy-4,4'-diaminobiphenyl in a reaction vessel equipped with a stirring device, a nitrogen introducing tube, and a drying tube, and pyridine 1. 74g
(0.022 mol) and 9.65 g of dimethylacetamide were cooled in an ice-water bath. 3,3'-dihydroxy-4,
When 4'-diaminobiphenyl is dissolved, 3.25-perfluorononenyloxyisophthalic acid dichloride 3.25
g (0.005 mol) and isophthalic dichloride 1.0
2 g (0.005 mol) are added in small portions. After stirring for 5 hours, the reaction solution was poured into a large amount of methanol to precipitate the polymer. Filtration of the precipitated polymer,
After washing with methanol, drying was performed to obtain polyhydroxyamide.

Synthesis Example 4 3.66 g (0.01 mol) of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane was placed in a reaction vessel equipped with a stirring device, a nitrogen introducing tube, and a drying tube. , 1.74 g (0.022 mol) of pyridine and 9.2 g of dimethylacetamide were cooled in an ice-water bath. 2,2
When bis- (3-amino-4-hydroxyphenyl) hexafluoroparopane is dissolved, 0.65 g (0.06 g) of 5-perfluorononenyloxyisophthalic acid dichloride is added.
01 mol), 1.83 g of isophthalic acid dichloride (0.8 mol).
009 mol) is added in small portions. After stirring for 5 hours, the reaction solution was poured into a large amount of methanol to precipitate the polymer. The precipitated polymer was separated by filtration, washed with methanol, and dried to obtain polyhydroxyamide.

Synthesis Example 5 2.16 g (0.01 mol) of 3,3'-dihydroxy-4,4'-diaminobiphenyl was added to a reaction vessel equipped with a stirring device, a nitrogen inlet tube, and a cooling tube containing balls. Acid 10
Add 0 g and heat to 200 ° C. 6.12 g (0.01 mol) of 5-perfluorononenyloxyisophthalic acid is added and reacted at 200 ° C. for 4 hours. The reaction solution was poured into water to precipitate the polymer. Filtration of the precipitated polymer,
After washing with water, a dilute aqueous solution of sodium hydrogen carbonate, water and methanol, and drying, polybenzoxazole was obtained.

Synthesis Example 6 3,3'-Bis (trimethylsiloxy) -4,4 'was placed in a reaction vessel equipped with a stirring device, a nitrogen inlet tube and a drying tube.
-Bis (trimethylsilylamino) -biphenyl 5.0
5 g (0.01 mol), dimethylacetamide 17.3 g
And cooled in an ice-water bath. 6.49 g (0.01 mol) of 5-perfluorononenyloxyisophthalic dichloride are added in small portions. After stirring for 5 hours, the reaction solution was poured into a large amount of methanol to precipitate the polymer. The precipitated polymer was separated by filtration, washed with methanol, and dried to obtain polyhydroxyamide.

Synthesis Example 7 2,2-bis (4- (trimethylsiloxy) -3) was added to a reaction vessel equipped with a stirring device, a nitrogen inlet tube, and a drying tube.
6.55 g (0.01 mol) of (trimethylsilylamino) hexafluoropropane, dimethylacetamide 1
9.5 g was put and cooled in an ice water bath. 6.49 g of 5-perfluorononenyloxyisophthalic acid dichloride
(0.01 mol) are added in small portions. After stirring for 5 hours, the reaction solution was poured into a large amount of methanol to precipitate the polymer. The precipitated polymer was separated by filtration, washed with methanol, and dried to obtain polyhydroxyamide.

Synthesis Example 8 In the same manner as in Synthesis Example 1, except that 6.49 g of 5-perfluorononenyloxyisophthalic acid dichloride shown in Synthesis Example 1 was replaced by 2.03 g (0.01 mol) of isophthalic acid dichloride. Polyhydroxyamide was obtained.

Synthesis Example 9 Synthesis Example 7 was conducted using 2.03 g (0.01 mol) of isophthalic acid dichloride instead of 6.49 g of 5-perfluorononenyloxyisophthalic acid dichloride of Synthesis Example 7.
And a polyhydroxyamide was obtained.

Examples 1 to 7 and Comparative Examples 1 and 2 The polymers obtained in Synthesis Examples 1 to 9 were diluted with dimethylacetamide to about 5% to prepare a composition for a liquid crystal alignment film. This solution was spin-coated on two glass substrates with ITO transparent electrodes, and dried by heating at 250 ° C. for 1 hour to form a polybenzoxazole layer having a thickness of 500 °. Next, the surface of the polybenzoxazole layer is subjected to a rubbing treatment to obtain a liquid crystal holding substrate. The two substrates are combined with the polybenzoxazole layers facing each other so that the rubbing directions are antiparallel. Agent E
Sealed with N-1000 (trade name of Hitachi Chemical Co., Ltd.), and heat-cured at 120 ° C. for 2 hours to assemble a test liquid crystal display cell. Liquid crystal ZLI-1132 (trade name, manufactured by Merck) was sealed in the test liquid crystal display cell at room temperature 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 1 shows the results measured together with the used polyhydroxyamide and polybenzoxazole (synthesis examples for producing the same).

[Table 1]

Next, using the polyamic acid solution (composition for liquid crystal alignment film) obtained in Synthesis Examples 1 to 7, an ITO transparent electrode was formed so as to have 640 × 200 dots by the same method as described above. A polyimide layer is formed on the substrate which has been rubbed, and the surface of the
The cell was assembled so as to be twisted, and a liquid crystal adjusted by adding a chiral agent S-811 (manufactured by Merck) to the liquid crystal at room temperature 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 has a 6
The display was able to be driven by 40 × 200 dots, and high display quality was obtained without occurrence of poor orientation such as domains.

[0054]

According to the liquid crystal alignment film of the first aspect,
A high pretilt angle can be obtained stably, and the liquid crystal holding substrate according to claim 2 can also exhibit an excellent pretilt angle.
The liquid crystal display element according to the third aspect also exhibits an excellent pretilt angle, and the liquid crystal alignment film according to the first aspect can be obtained from the liquid crystal alignment film material according to the fourth and fifth aspects.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G02F 1/1337 520 C08G 69/32 C08G 69/48 C09K 19/02 C09K 19/38

Claims (5)

(57) [Claims] [Chemical formula 1] [Chemical formula 1] [However, in the general formula (I), Rf is -C _n F _2n-1 (where, n represents a is 6-12 integer) indicates the hydrogen of the benzene ring may be substituted, X is A tetravalent organic group containing an aromatic ring, wherein two sets of N and O are respectively bonded to the aromatic ring in X at the ortho position so as to form a five-membered ring] Liquid crystal alignment film containing fluorine-containing polybenzoxazole. 2. A liquid crystal holding substrate having the liquid crystal alignment film according to claim 1. 3. A liquid crystal display device comprising an electrode provided thereon, and further comprising a liquid crystal holding substrate on which the liquid crystal alignment film according to claim 1 is provided facing the liquid crystal. 4. A compound of the general formula (II) [However, in the general formula (II), Rf is -C _n F _2n-1 (where, n represents a is 6-12 integer) indicates the hydrogen of the benzene ring may be substituted, X is A tetravalent organic group containing an aromatic ring, and NH and OH are bonded to the aromatic ring in X at the ortho position to each other.] Materials for alignment film. 5. A compound represented by the following general formula (III): [However, in the general formula (III), Rf is -C _n F _2n-1 (where, n represents a is 6-12 integer) indicates the hydrogen of the benzene ring may be substituted] represented by And an acid component containing an aromatic dicarboxylic acid or an amide-forming derivative thereof represented by the general formula (IV): (Wherein, R ¹ , R ² , R ³ and R ⁴ each independently represent hydrogen or a trialkylsilyl group, X represents a tetravalent organic group containing an aromatic ring, —NH—R ¹ and -OR
³ and —NH—R ² and —O—R ⁴ are respectively bonded to the aromatic ring in X at the ortho position) by reacting an aminophenol component containing a bis (aminophenol) compound represented by A material for a liquid crystal alignment film comprising the obtained fluorine-containing polybenzoxazole-based resin.