JPH03216620A - Composition for liquid crystal oriented film, liquid crystal oriented film, liquid crystal crimping substrate, and liquid crystal display element - Google Patents

Abstract

PURPOSE:To maintain >=7 deg. pretilt angle by using specific polyimide as a liquid crystal oriented film. CONSTITUTION:The compsn. for the liquid crystal oriented film contg. the diamine compd. contg. the fluorine atom expressed by formula 1, diamine compds. exclusive of this compd. at need, or the tetracarboxylic dianhydride having the silicon atom expressed by formula II and a compsn. for liquid crystal oriented film contg. polyamide acid at need are used. In the formula I, Ar1 to Ar4 denote an arom. group; R1, R2 denote 1 to 5C fluorinated alkyl group; R3 to R6 denote 1 to 10C fluorinated alkyl group; X1, X2 denote -O-, etc.; (a) to (c) denote 0 or 1; (d) to (g) denote 1 to 4 integer. In the formula II, Ar5, Ar6 denote an arom. group; R7 to R10 denote 1 to 10C alkyl group; 1 to 10C substd. alkyl group, etc., arom. group; X1, X4 denote formula III, etc. The pretilt angle is specified at >=7 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a composition for a liquid crystal alignment film, a liquid crystal alignment film using the same, a liquid crystal holding substrate, and a liquid crystal display element.

(Prior Art) Conventionally, an STN (super twisted nematic) system has been used in liquid crystal display elements for large displays in order to improve visual characteristics. This is a method in which the long axis direction of the liquid crystal molecules within the cell is twisted by 200 to 2700 degrees (200 to 2700 degrees).
~270° twist) The larger the twist angle, the better the visual characteristics. In order to increase the twist angle in these STN type elements K, it is necessary to have a large angle (pretilt angle) between the liquid crystal molecules and the glass substrate on which the alignment film is formed. In order to obtain a twist angle of 260° or more, an alignment film material with a Gretilt angle of 7° or more is required.

However, with conventional polyimide-based alignment films, it was not possible to increase the pretilt angle to 7° or more.
It was put into practical use with a twist angle of around 240°.

(Problem M to be Solved by the Invention) The object of the present invention is to solve the problems of the prior art and provide a composition for a liquid crystal aligning film that can make the pretilt angle 7° or more, and a liquid crystal aligning film composition using the composition. The present invention provides a film, a liquid crystal holding substrate, and a liquid crystal display element.

(Means for Solving the Problem) The inventors of the present invention have conducted extensive research in view of the problems of the prior art described above. The inventors have discovered that when a specific polyimide is used as a liquid crystal alignment film, the pretilt angle becomes 7 degrees or more, and the present invention has been achieved.

That is, the present invention provides (a) general formula (I) Rt R4 * RS and R6 are heptafluorinated alkyl groups having 1 to 10 carbon atoms with the same or different structures, XI and X2 are 10- or -S1, and a, b and C are θ''! hx,d
, e, f and g represent 0 or an integer from \'il to 4.

However, if the value of a, b and C is O, either or both of d and g will not be 0, and if a is O and either or both of b and C is 1, then d, e, f A diamine compound having a fluorine atom, (b) if necessary, (a
Diamine compounds other than 1, (C) general 2 full) (...) (wherein, Ar5 and Ar6 are aromatic groups * R?
e FLs 1- and R+◎ are alkyl groups having 1 to 10 carbon atoms, substituted alkyl groups with 1 to Lot carbon atoms, or aromatic groups. x 1 and Tetracarpone dianhydride having a silicon atom represented by (integer from 1 to 5'1), and (d) the required K! ) (A composition for a liquid crystal alignment film comprising a polyamic acid obtained by reacting a tetracarboxylic dianhydride other than Cl in a solvent, a β liquid crystal alignment film formed from the composition, a liquid crystal having this alignment film) Facing the supporting board and liquid crystal,
The present invention relates to a liquid crystal display element having the liquid crystal alignment film on a liquid crystal holding substrate provided with electrodes.

As the diamine compound (a) having a fluorine atom represented by the above general formula (1) used in the present invention, for example, 2
．． 2-bis(4-aminophenyl) -1. 1, 1
．． 3. λ3-hexafluoropropane, λ3-bis(4
-aminophenyl) -1. 1, 1, s 2, 4
, 4, 5, 5. 5-tecafluorobentane, 2
．． 2-bis(4-7minophenyl) - 1. 1,
1. 3, 3. 4, 4. 4-octafluorobutane. 2.2-bis(3-aminophenyl)1,1,1
,3,3.3-hexafluoropropane. 2.2-bis i4-(4-aminophenoquine》phenyl}-1.1
, 1,43.3-hexafluoroproban,z2-bis(4-(4-aminophenoxy)funinyl}1,
1, 1. 2, 2, 4. 4. 5. 5. 5
-dicafluoropentane, 2.2-bis(4-(4-
aminophenoxy)phenyl)-1. 1, 1, 3
, 3, 4.44-octafluorobutane, 2.2-
Bis{3-(4-aminophenoxy)phenyl}-1.
1, 1. & 3,3-hexafluoropropane,
2.2-bis{4-(3-aminophenoxy)phenyl}-1. 1, 1, λ-containing 3-hexafluoropropane, 2.2-bis(3-(3-aminophenoxy)phenyl} - 1. 1, 1, 3, & 3-hexafluoropropane, 2.2-bis( 4-(4-aminophenoxy)phenyl} - 1. 1, 1, 3,
3. 3-hexafluoropropane, 4.4'-diamino-3.3'-di(trifluoromethyl)biphenyl, 4.4'-diamino-3.3'-di(penta7fluoroethyl)biphenyl, 4.4'-diamino-3.3'-
Di(pentafluoroprobyl)biphenyl, 4.3'-
Diamino-λ4'-di(trifluoromethyl)biphenyl, 3,3'-cyamino-4,4'-di(trifluoromethyl)biphenyl, 4,4'-diamino-3,3'
-di(trifluoromethyl)-5'-di(pentafluoroethyl)biphenyl. 4.4'-pis(4-amino-3-trifluoromethylphenoxy)piphenyl, 4
．． 4'-bis(4-amino-3-pentafluoroethyl)biphenyl, &3'-bis(4-amino-3-trifluoromethylphenoxy)biphenyl, 4.4'-bis(3-amino-4-trifluoromethyl) phenoxy)biphenyl, 4.4'-pis(4-aminophenoxy)-3'-ditrifluoromethylbiphenyl, λ3'-bis(4-aminophenoxy)-44'-ditrifluoromethylbiphenyl, 4.4 '-bis(4-aminophenoxy)-3.3'-dipentafluoroethylbiphenyl, 4.4'-(4-aminophenoxy) 3'-ditrifluoromethylbiphenyl, 2.2'-bis(4 -amino-3-trifluoromethylphenyl)-1,t. t
．． a, a, 3-hexafluoropronone, 2.2'-
Bis(4-amino-3-pentafluoroethyl)-1.
1,1.3,3.3-hexafluoropropane. 3.3
'-Bis(4-amino-3-trifluoromethylphenyl) - 1. 1. 1. 2, Z 4. 4.
5, 5. 5-Decafluoropentane. 3.3'-bis(4-amino-3-pentafluoroethyl phenyl)
-1. 1. 1. Z Z 4. 4, 5, 5
．． 5-Decafluoropentane. L2'-bis {4-(
4-aminophenoxy)-3-trifluoromethylphenyl} - 1. 1, 1. a 3,3-hexafluoropropane. 2.2'-bis(4-(4-amino-3-trifluoromethylphenoxy)}-1.1.1
,3,3.3-hexafluoropropane,4,4'-bis(4-amino-3-trifluoromethylphenoxy)
-33'-cy(}lifluoromethyl)biphenyl, 42
'-Pis(4-(4-amino-3-trifluoromethylphenoxy)7enyl} - 1. 1. 1. 3,
Examples include λ3-hexafluoropropane. These can be used in 1s or in combination of two or more kinds.

H
．． 1.3-bis(&4-dicarboxyphenyl)-1.
1.3.3-Tetramethyldisiloxane dianhydride. 1.
3-bis(&4-dicarboxyphenyl)-1.1, shallow 3-tetraethyldisiloxane dianhydride, 1.3-bis(&4-dicarboxyphenyl)-1. 1. λ3
-tetraphenyldisiloxane dianhydride, 1,3-bis{3-(&4-dicarboxybenzoyloxy)propyl l - 1. 1, 3. 3-Tetramethyldisiloxane dianhydride, 1.3-bis+2-(&4-dicarboxybenzoyloxy)ethyl l - 1. 1, & 3
-tetramethyldisiloxane dianhydride, 1.3-bis+
5-(&4-dicarboxypenzoyloxy)pentyl) 11. 1. λ3-Tetramethyldisiloxane dianhydride, 1,3-bis(3-(3,4-dicarboxypenzoyloxy)probyl)-1, 1.3.3-tetraphenyldisiloxane dianhydride, bis( 3.4-Dicarboxybenzoyloxy)diphenylsilanianhydride, bis(3.4-dicarboxybenzoyloxy)dimethylsilanianhydride, bis(3.4-dicarboxybenzoyloxy)ethylmethylsilanianhydride ,1.3
-Bis(λ4-dicarbonyl/phenyl) -1.3-
, 'Methyl-1,3-diethyl di/loxanianhydride,
1.3-bis(a4-dicarboxyphenyl)-1.1
．． 3.3.5.5-Hexamethyltrisiloxane dianhydride, 1.3-bis(3.4-dicarboxy7phenyl)
-1. 1. &h s, s,7,7-octamethyltetrasiloxane dianhydride, 1,3-bis(3,4
-dicarboxyphenyl)-1.1, 3, 5, 5
, 7, 7, 9. 9-decamethylbentasiloxane dianhydride, 1.3-bis(3.4-dicarpoxyphenyl) - 1. 1. & 3, 5, 5, 7,
7, 9, 9, 1 1. 1 1-dodecamethylhexasiloxane dianhydride, etc.
Seed-! Or two or more types can be used together.

Further, the diamine compound (at) having a fluorine atom represented by the general formula (I) according to claim 2 and the general formula (
Diamine compounds other than (a) and tetracarboxylic dianhydrides other than (C) used in conjunction with silicon atom-containing tetracarboxylic dianhydride (c) represented by If) are particularly limited. However, examples of diamine compounds other than [a) include m-phenylenediamine. p-7 enylene diamine. m-xylene diamine. p-xylene diamine, 4.4'-diaminodiphenyl ether, 4.4'-diaminodiphenylmethane, λ
3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3. '5.5'-tetramethyl-4.4'-diaminodiphenylmethanet2.2'-bis(4-aminophenyl)broban, 4.4'-methylene dianiline, benzine, 4.4'-diaminodiphenyl sulfide, 4
．． Examples include 4'-diaminodiphenyl sulfone, L5-diaminonaphthalene, 3'-dimethylbenzine, and 3,3'-dimethoxybenzine. These can be used alone or in combination of two or more Fi.

In addition, as tetracarboxylic dianhydrides other than IC),
For example, pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride. 3, 3, '4.4'
-diphenyltetracarboxylic dianhydride, 1,2,5.
6-naphthalenetetracarboxylic dianhydride, 2,Z'-containing 3'-diphenyltetracarboxylic dianhydride, thiophene-Za45-tetracarboxylic dianhydride. z2-bis(λ4-carpoquinphenyl) fropanni anhydrous ah.
3. 4-dicarboxyphenylsulfone dianhydride, perylene & 4. 9. 1 0-Tetracarboxylic dianhydride, bis(a4-dicarboxyphenyl)ether dianhydride. :l'4.4'-benzophenonetetracarpone dianhydride and the like.

Two or more of these can be used together.

The polyamic acid in the present invention has (a) the general formula (1
) A diamine compound having a fluorine atom represented by (a) and, if necessary, a diamine compound other than (a), (C) a tetracarboxylic dianhydride having a silicon atom represented by the above general formula (n), as necessary. Accordingly, it is obtained by reacting a tetracarboxylic dianhydride other than (C) in a solvent.

In this case, the amount of the diamine compound having a fluorine atom represented by the above general formula (1) to be used is 0.5 mole or more based on the total diamine component, and the diamine compound having a silicon atom represented by the above general formula (It) is used. The amount of tetracarboxylic dianhydride used is.
The amount is preferably 0.5 mole or more based on all the tetracarboxylic dianhydrides. Preferably, the total number of moles of the diamine component and the total number of moles of the tetracarboxylic dianhydride are approximately equal in mole K, and the reaction is carried out.

The solvent used in the reaction is an inert solvent, and it is not necessary to dissolve all of the monomers mentioned above. It is preferable to use one that dissolves the polyamic acid produced, such as N-methyl-2
-pyrrolidone. N. N-dimethylformamide, N
．． N-diethylformamide, dimethyl sulfoxide.
Hexamethylphosphoramide, tetramethylsulfone.
Examples include 1,4-dioxane. These may be used alone or in combination. In addition to these solvents, K. A solvent can be added before or after the reaction to improve the applicability to the glass substrate. Examples of the solvent used include ehaptyl cellosolve, butyl cellosolve acetate, xylene, and toluene.

The polyamic acid obtained in the above reaction is heated (for example, 10
0 to 400°C) and/or chemical treatment (e.g., acetic anhydride treatment). Becomes polyimide.

The composition for a liquid crystal alignment film containing the polyamic acid of the present invention may be, for example. Indium T
K is coated on a glass substrate on which a transparent electrode such as inQxide is formed, and the polyimide layer is dehydrated and ring-closed to form a polyimide layer.

As for the application method. Immersion method. Printing method. A method such as a spraying method is used. The dehydration ring closure temperature can be arbitrarily selected within the range of 150 to 400°C, preferably 150 to 300°C. Also, the heating time Fi is 1 minute to 6 hours, preferably 1 minute.
It is said to be from minutes to 3 hours.

The polyimide layer is coated with K.I. to improve the adhesion between the glass substrate and the polyimide layer. During this time, a coupling agent such as a silane coupling agent or a titanium coupling agent may be used.

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

The liquid crystal alignment film obtained using the composition for liquid crystal alignment film of the present invention is. Liquid crystal display elements K of the STN method with a twist angle of 260 to 270[deg.] are particularly suitable.

(Example) The present invention will be explained below using examples.

Example 1 2.2-bis{4-(4-aminophenoxy}phenyl}-1. 1, 1, 3, 3. 19.44 g (0.037 mol) of 3-hexafluoropropane was converted into N-
Add to 170 g of methyl-2-pyrrolidone, stir well, and add to 170 g of methyl-2-pyrrolidone. 4'-diphenylcarboxylic dianhydride 4.699 (0.016 mol) and pyromellitic dianhydride 3.489 (0.016 mol) and 1
．． 3-bis(3.4-dicarboxyphenyl)-1.1
, 3.3-tetramethyldisiloxane dianhydride 149 (
After adding 0.005 mol) and reacting at 50°C for 5 hours, a pale yellow viscous solution was formed.

The viscosity of this solution was adjusted, and the solution was coated on two glass substrates with transparent ITO electrodes using a sinter coating, heated at 250°C for 1 hour, the solvent was removed, and the polyamide film was removed. Perform dehydration ring closure.
A polyimide layer with a thickness of 500A was formed. The surfaces of this layer on two glass substrates were rubbed to obtain a liquid crystal holding substrate as a liquid crystal alignment film, and this was combined with two polyimide layers facing each other so that the wrapping directions were antiparallel. The periphery was sealed with epoxy sealant EN-1000 (trade name manufactured by Hitachi Chemical Co., Ltd.), and after heating and curing at 180°C for 2 hours, liquid crystal ZLI-1132 (trade name at Merck & Co., Ltd. exhibition) was sealed inside at room temperature. Then, a liquid crystal cell was formed. After heating this liquid crystal cell at 120°C, which is a temperature higher than TN■ (71°C) of liquid crystal ZLI-1132, for 1 hour, the pretilt angle of the cell was measured using a laser beam, and the pretilt angle was 13.8. ° de l :>. This satisfied the requirements for a 270° twist alignment film for liquid crystal display elements.

Next, using the above solution, 640 x 20
A polyimide layer was formed on two glass substrates on which ITO transparent electrodes were formed so as to have 0 dots K, and the surface of this layer was rubbed, and the twist angle was set to 27 in the same manner as above.
Combine so that the angle is 0°. Seal the surrounding area. A liquid crystal prepared by adding a chiral agent S-811 (trade name, manufactured by Merck & Co., Ltd.) to the above liquid crystal was sealed at room temperature and heated at 120° C. for 1 hour to form a liquid crystal display element.

The liquid crystal display element can be driven at 640 x 200 dots,
High display quality was achieved with no alignment defects such as domains.

Example 2 2.2-bis(4-aminophenyl) - 1. 1.
1. 3,3.3-hexafluoropropane 15.5
After adding 49 (0.046 mol) to 170 g of N-methyl-2-pyrrolidone and stirring thoroughly, 3, λ' 4.
4'-diphenylcarboxylic dianhydride6. 4 7
g (0.02 2 mol), biromellitic dianhydride4. sog (0.022 mol) and 1.3-bi,(
(a4-dicarboxyphenyl) - 1. 1.3.
3 -f } La7x Nildine Roxanni Anhydride 1.3
19 (0.002 mol) was added and reacted at 50°C for 5 hours, resulting in a pale yellow viscous solution.

Using this solution, a liquid crystal cell was formed by processing in the same manner as in Example 1, and after heating at 12° C. for 1 hour, the pretilt angle was measured, and the pretilt angle was 11.0'.

Furthermore, a liquid crystal display element was formed using this solution in the same manner as in Example 1, but no alignment defects occurred and the display quality was high.

Example 3 44'-bis(4-amino-3-tri7fluoromethylphenoxy)biphenyl 1 6.8 7 g (0.033
mol) was added to 170 g of N-methyl-2-pyrrolidone, and after thorough stirring, 3.659 g of pyromellitic dianhydride was added.
(α017 mol) and 1.3-bis(3-(3.4-
dicarboxypenzoyloxy)7' o hill) -
9.48 g (0.017 mol) of l, l, 3.3-tetramethyldisiloxane dianhydride was added and reacted at 50°C for 5 hours. The result was a pale yellow viscous solution.

Using this solution, a liquid crystal cell was formed by processing in the same manner as in Example 1, and after heating at 120° C. for 1 hour, the pretilt angle was measured, and the gretilt angle was 9.0°.

Furthermore, a liquid crystal display element was formed using this solution in the same manner as in Example 1, but no alignment defects occurred and the display quality was high.

Example 4 19.99 (0.038 mol) of 2.2-bis(4-(4-aminophenoxy)phenyl l-1.1.1.&λ3-hexafluoropropane) was converted into N-methyl-2
- After adding virolidone 1706K and stirring thoroughly, aa
'4,4'-diphenylcarboxylic dianhydride 5.529
(0.019 mol), biromellitic dianhydride 4.09
g (0.019 mol) and 0.499 (0.001 mol) of 1.3-bis(3.4-dicarpoxybenzoyloxy)diphenylsilanhydride were added and reacted at 50°C for 5 hours. , it became a pale yellow viscous solution.

Using this solution, a liquid crystal cell was formed by processing in the same manner as in Example 1. After heating at 120° C. for 1 hour, the pretilt angle was measured and found to be 9.5°.

Furthermore, a liquid crystal display element was formed using this solution in the same manner as in Example 1. No alignment defects occurred and the display quality was high.

(Effects of the Invention) According to the composition for liquid crystal alignment film of the present invention. A liquid crystal alignment film having a pretilt angle of 7° or more can be formed. In addition, by using a liquid crystal holding substrate having this liquid crystal alignment film,
A liquid crystal display element twisted by 0 to 270 degrees has high display quality without causing alignment defects such as domains.

Claims (1)

[Claims] 1. (a) General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, Ar_1, Ar_2, Ar_3 and Ar_4
is an aromatic group, R_1 and R_2 are fluorinated alkyl groups having 1 to 5 carbon atoms, and R_3, R_4, R_5 and R_6 are 1 to 10 carbon atoms having the same or different structures.
fluorinated alkyl groups up to, X_1 and X_2 are -O
- or -S-, a, b and c are 0 or 1,
d, e, f and g represent 0 or an integer from 1 to 4. However, if a, b, and c are all 0, either or both of d and g will not be 0, and if a is 0, b and c
If either or both of are 1, any of d, e, f, and g will not be 0, and all of d, e, f, and g will be 0.
(b) Diamine compounds other than (a) if necessary (c) General formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) (In the formula, Ar_5 and Ar_6 are aromatic groups, R_7,
R_8, R_9 and R_1_0 are alkyl groups with 1 to 10 carbon atoms, substituted alkyl groups or aromatic groups with 1 to 10 carbon atoms, , tables, etc. ▼ (n is an integer from 1 to 10), k and m are 0 or 1, L is 0 or an integer from 1 to 5) A composition for a liquid crystal alignment film comprising a polyamic acid obtained by reacting a tetracarboxylic dianhydride and (d) a tetracarboxylic dianhydride other than (c) if necessary in a solvent. 2. The amount of the diamine compound represented by the general formula (I) to be used is 0.5 mol% or more based on the total diamine component and/or the amount of the diamine compound represented by the general formula (I) based on the total tetracarboxylic dianhydride component.
II) The amount of tetracarboxylic dianhydride used is 0.
．． The composition for a liquid crystal alignment film according to claim 1, wherein the content is 5 mol% or more. 3. A liquid crystal alignment film formed from the composition for liquid crystal alignment film according to claim 1 or 2. 4. A liquid crystal holding substrate having a liquid crystal alignment film formed from the composition for a liquid crystal alignment film according to claim 1 or 2. 5. On the liquid crystal holding substrate with electrodes facing the liquid crystal,
A liquid crystal display element having a liquid crystal alignment film obtained from the composition for liquid crystal alignment film according to claim 1 or 2.