JPH0455821A - Coating solution for liquid crystal cell, liquid crystal oriented film, liquid crystal inserting substrate and liquid crystal display device - Google Patents

Abstract

PURPOSE:To prevent the deterioration of the display ability of a liq. crystal display device by using a coating soln.obtd. by adding polyamic acid and an amido compd. obtd. by allowing 1 mol aliphatic dicarboxylic acid to react with about 2 mol aliphatic monoamine to a solvent dissolving them. CONSTITUTION:Polyamic acid and an amido compd. obtd. by allowing 1 mol aliphatic dicarboxylic acid to react with about 2 mol aliphatic monoamine are added to a solvent dissolving them to obtain a coating soln. for a liq. crystal cell. The polyamic acid is obtd. by allowing tetracarboxylic acid dianhydride to react with diamine in the presence of a solvent preferably at <=50 deg.C and the amino compd. is obtd. by allowing 1 mol aliphatic dicarboxylic acid to react with about 2 mol aliphatic monoamine in the presence of a solvent and an optionally about 2 mol aliphatic monoamine in the presence of a solvent and an optionally added catalyst such as phosphoric acid preferably at 100-150 deg.C. A large tilt angle to liq. crystal molecules can be maintained and display ability is not deteriorated.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a coating liquid for liquid crystal cells, and more specifically, a coating liquid for liquid crystal cells that can increase the tilt angle of liquid crystal molecules and make the liquid crystal display easier to see. Coating liquid.

The present invention relates to a liquid crystal alignment film, a liquid crystal holding substrate, and a liquid crystal display element using the same.

(Prior Art) As a means for favorably aligning liquid crystal molecules on a transparent substrate on which electrodes are formed, there is a method of forming an oblique evaporation film of silicon oxide or the like, or a method of forming a film of organic polymer or the like.

A method of rubbing the film is known.

However, obliquely deposited films such as silicon oxide have different alignment abilities depending on the type of liquid crystal material, and some liquid crystal materials do not align at all, so this poses a major problem when using a mixture of various liquid crystals. Become. Further, since vapor deposition is performed in a vacuum system, the equipment cost is high, and since it is a batch process, mass production is poor. On the other hand, there is a method in which a resin film with excellent heat resistance, such as polyimide resin, is subjected to rubbing treatment.

Although it can be used for many liquid crystal materials, there is a problem that the #x,N orientation angle (tilt angle) of the liquid crystal molecules becomes low, resulting in a decrease in the display ability.

Therefore, as liquid crystal display methods are utilized in a wide range of industrial fields, there is a need for coating liquids for liquid crystal cells with even better performance.

(Problem to be solved by the invention) The object of the present invention is to solve the problems of the prior art described above.

It is an object of the present invention to provide a liquid crystal cell coating liquid that can maintain a high tilt angle with respect to liquid crystal molecules, and to provide a liquid crystal alignment film, a liquid crystal holding substrate, and a liquid crystal display element using the same.

(Means for Solving the Problems) The present invention provides an amide compound obtained by reacting (A) a polyamic acid, (B) 1 mole of an aliphatic dicarboxylic acid, and about 2 moles of an aliphatic monoamine; A liquid crystal cell coating liquid comprising a solvent that dissolves an acid and an amide compound, a liquid crystal alignment film formed from the liquid crystal cell coating liquid,
The present invention relates to a liquid crystal sandwiching substrate on which the liquid crystal alignment film is formed and a liquid crystal display element having the liquid crystal sandwiching substrate.

The polyamic acid (ASFi, tetracarboxylic dianhydride and diamine used in the present invention) in the presence of a solvent,
Preferably, the reaction is carried out at a temperature lower than or equal to 50°C. It is preferable that the proportions of tetracarboxylic dianhydride and diamine used are equimolar.

As a solvent, N,N-dimethylformamide.

Highly polar compounds such as N,N-dimethylacetamide, N,N-dimethylsulfoxide, and N-methyl-2-pyrrolidone are preferred.

Examples of the tetracarboxylic dianhydride include 1, pyromellitic dianhydride, 2,3,6.7-naphthalenetetracarboxylic dianhydride, 3,3. '44'-diphenyltetracarboxylic dianhydride, 1,2,5.6-naphthalenetetracarboxylic dianhydride, 2.2. '3. λ'-diphenyltetracarboxylic dianhydride, 42-bis(he4-biscarboxyphenyl)propane dihydride.

3.4-dicarboxyphenylsulfone dianhydride.

Cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, perylene-3,4゜9.10-tetracarboxylic dianhydride, bis(λ4-dicarboxyphenyl) Eterni anhydride, a.

Part 4,4'-benzophenonetetracarboxylic dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-
1,1,3,3-tetramethyldisiloxane dianhydride and the like are used. These may be used alone or in combination of two or more.

Examples of diamines include m-phenylenediamine, p-
-phenylenediamine, m-xylenediamine, 2.2
'-Diaminodiphenylpropane, p-xylene diamine, 4.4'-diaminodiphenyl ether, 4.4'
-diaminodiphenylmethane, containing 3-dimethyl-4,4
'-Diaminodiphenylmethane.

3.3. '5.5'-tetramethyl-4.4'-diaminodiphenylmethane, 2.2'-bis[4(4-aminophenoxy)phenyl]propane, 4.4'-methylene dianiline, benzidine, 4.4'- Aminodiphenylsulfide, 4,4'-diaminodiphenylsulfone.

4.4'-di(4-aminophenoxy)diphenylsulfone, 1.5-diaminonaphthalene, 3.3'-dimethylbenzidine, 3.3'-dimethoxybenzidine, etc. are used. These may be used singly or in combination. In addition, these diamines can also be used in combination with diaminomonoamide compounds I' such as 1,4-diaminobenzene-2-carbonamide and 4,4'-diamino-diphenyl ether-3-carbonamide.

The amide compound (Bl) used in the present invention is prepared by mixing 1 mole of aliphatic dicarboxylic acid and about 2 moles of aliphatic monoamine in the presence of a solvent and, if necessary, a catalyst such as phosphoric acid at a temperature of preferably 100 to 150°C. It is obtained by reacting at a temperature of .

In view of the purity of the resulting amide compound, the amount of aliphatic monoamine is approximately 2 mol, preferably 12 mol, of F per 1 mol of aliphatic dicarboxylic acid.

As a solvent, N,N-dimethylformamide.

Highly polar compounds such as N,N-dimethylacetamide, N,N-dimethylsulfoxide, and N-methyl-2-pyrrolidonato are preferred.

As the aliphatic dicarboxylic acid, dicarboxylic acids having 2 to 20 carbon atoms are preferably used.9 For example, saturated or unsaturated dicarboxylic acids such as oxalic acid, adipic acid, azelaic acid, cepatic acid, fumaric acid, maleic acid, malic acid, etc. Examples include fatty acids. These Fi2 harvests or more may be used.

As the aliphatic monoamine, an amine having 2 to 25 carbon atoms is preferably used, such as n-hexylamine, n-
-octylamine, n-decylamine, n-dodecylamine, n-hexadecylamine, stearylamine, 1
．． Examples include 3-dimethylbutylamine, 1,5-dimethylhexylamine, and 2-ethylhexylamine. Two or more of these Vi types may be used.

The proportions of the polyamic acid fAl and the amide compound (Bl used are by weight).

7ih'4hi8things ≦. , 50°02≦polyamic acid. This usage ratio is 0.02
If it is less than 0.5, the effect of increasing the tilt angle will not be sufficiently obtained, and if it exceeds 0.5, the strength of the formed film.

Physical properties such as heat resistance may deteriorate.

The polyamic acid fA) and the amide compound (B) are dissolved in a solvent (C) that dissolves them to form a liquid crystal cell coating liquid. The solvent (q) used is the same as the solvent used in the synthesis of the polyamic acid amide compound. There are no particular restrictions on the mixing method, but 2 Usually, stirring and mixing at a temperature of 50°C or less is used. be done.

The coating liquid for liquid crystal cells of the present invention is prepared by a dip method, a spinner method,
It is applied onto a substrate on which electrodes are formed by a spray method, a printing method, a brush coating method, or the like.

After that, 100-400℃, preferably 250-350℃
The polyamic acid is heat-treated at a temperature of 0.degree. C. to dehydrate and ring-close the polyamic acid, and then subjected to a rubbing treatment to obtain a polyimide-based liquid crystal alignment film.

A liquid crystal display element can be obtained by a known method using a liquid crystal holding substrate having this liquid crystal alignment film.

(Example) Hereinafter, the present invention will be explained in detail by way of implementation.

Example I 1.0 mol of 2,2-diaminodiphenylpropane, 0.8 mol of pyromellitic dianhydride and 1.3-bis(turime-4-dicarboxyphenyl)- in N-methyl-2-pyrrolidone. 0.2 mol of 1,1,3,3-tetramethyldisiloxane dianhydride was reacted to obtain polyamic acid, which is a precursor of polyimide. Further, 1.0 mol of adipic acid and 20 mol of stearamine were reacted in iN-methyl-2-pyrrolidone at 150° C. for 4 hours in the presence of 0.05 mol of phosphoric acid to obtain an amide compound.

5 each of the obtained polyamic acid and amide compound
N-methyl-2-pyrrolidone solutions were prepared to contain 1% and 1% by weight, and this solution was applied using a spinner onto a glass substrate on which indium oxide electrodes were formed. After that, after drying at 150℃ for 1 hour,
Heat treatment was performed at 0° C. for 1 hour to cause thermal dehydration and ring closure, thereby forming a polyimide coating film.

This coating film was rubbed in a certain direction with a cotton cloth to obtain a liquid crystal holding substrate having a polyimide liquid crystal alignment film, and two liquid crystal holding substrates and an epoxy sealing material EN-1000 (E
A cell was prepared by heat-pressing at 18°C for 1 hour using a liquid crystal (ZLI 113 manufactured by Merck & Co., Ltd.) containing biphenyl-based liquid crystal as its main component through the injection port formed in the cell.
2) was injected and the injection port was sealed with epoxy resin (photocurable type 3052B manufactured by Three Bond) to prepare a test liquid crystal display element.

Using this test element, the initial orientation and the
The orientation was examined after 100 hours in a 5-chip H atmosphere, and all showed good orientation. The liquid crystal tilt orientation angle of this cell was measured using a magnetic field capacitance method and was found to be 12°.

Comparative Example 1 A test liquid crystal display element was produced in the same manner as in Example 1, except that an N-methyl-2-pyrrolidone solution containing 6% by weight of polyamic acid and no amide compound was used. , initial orientation of this test element and 70°C
The orientation was examined after 100 hours in a 95 S RH atmosphere. Although the test element after 100 hours showed orientation, the liquid crystal tilt orientation angle determined by the magnetic field capacitance method was as small as 5°.

(Effects of the Invention) Since the liquid crystal cell coating liquid of the present invention can maintain a high tilt angle with respect to liquid crystal molecules, the display ability of a liquid crystal display element obtained using the liquid crystal cell coating liquid does not deteriorate.

Claims (1)

[Claims] 1. (A) polyamic acid, (B) aliphatic dicarboxylic acid 1
A liquid crystal cell coating liquid comprising an amide compound obtained by reacting 1 mole with about 2 moles of an aliphatic monoamine, and (C) a solvent that dissolves the polyamic acid and the amide compound. 2. The coating liquid for a liquid crystal cell according to claim 1, wherein the ratio of the polyamic acid and the amide compound used is such that the polymerization ratio is 0.02≦amide compound amount/polyamic acid amount≦0.5. 3. A liquid crystal alignment film formed from the liquid crystal cell coating liquid according to claim 1 or 2. 4. A liquid crystal holding substrate having a liquid crystal alignment film formed from the liquid crystal cell coating liquid according to claim 1 or 2. 5. On the liquid crystal holding substrate with electrodes facing the liquid crystal,
A liquid crystal display element comprising a liquid crystal alignment film obtained from the liquid crystal cell coating liquid according to claim 1 or 2.