JPS5814117A - Substrate for sandwiching liquid crystal - Google Patents

Abstract

PURPOSE:To obtain a film for homogeneous orientation which is highly adhesive and resistant to heat and is stable with time by using a polyhydradiimide siloxane type high polymer film. CONSTITUTION:Electrodes are provided on substrates, and the soln. of the siloxane bond-contg. polyhydrazide acid-amide acid obtd. by reaction of carboxylic anhydride such as pyromellitic anhydride, dihydrazide such as isophthatic dihydrazide, diamine such as p-phenylene diamine and diaminosiloxane such as 1,3- bis(amino propyl)-tetramethyl disiloxane is coated on said substrates and electrode and is heated to cause dehydration and ring closure of said siloxane bond- contg. polyhydrazide acid-amide acid, whereby the polyhydradiimide-siloxane type high polymer film is formed. It is preferable to use arom. compds. for the above-mentioned compds. in terms of heat resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides means for improving the quality of initial homogeneous alignment that can be used in liquid crystal display devices that require liquid crystal molecules to be homogeneously aligned in an initial state (unexcited state). This invention relates to a liquid crystal sandwiching substrate.

Conventionally, as a means to improve the homogeneous alignment of liquid crystal molecules in the initial state, methods of forming an obliquely vapor-deposited film of silicon oxide or the like on a substrate, or forming a film of various surface treatment agents, organic polymers, etc. have been used.

A method of rubbing the film is known. However, each of these known methods has drawbacks as described below.

That is, the orientation ability of the obliquely deposited film on the silicon oxide cylinder differs depending on the type of liquid crystal substance, and there are liquid crystal substances that do not align at all. This is a very serious problem when using a mixture of various liquid crystals to improve the temperature characteristics or electro-optical characteristics of the liquid crystal. In the method of forming a film of various surface treatment agents, organic polymers, etc. and then rubbing the film, the film has low heat resistance, so the film deteriorates due to heating during device assembly, resulting in a decrease in orientation. Most of them have drawbacks such as oxidation, and only heat-resistant organic polymers such as polyimide have good heat resistance for orientation regulation.

However, these heat-resistant polyimide thread molecules generally have a strongly colored cured film, and therefore, the use of these films has the disadvantage that the appearance of a liquid crystal display element is significantly impaired. In addition, the polyimide Kurushima molecular film has poor adhesion to the substrate surface, resulting in partial peeling of the film during rubbing treatment, resulting in poor orientation such as the formation of domains.

The present inventors conducted studies to eliminate the above-mentioned drawbacks of the prior art, and as a result, they arrived at the present invention. In other words, the present invention allows the molecular axis of liquid crystal to be aligned parallel to the substrate surface and in the characteristic direction of the substrate surface, regardless of the liquid crystal substance, and this liquid crystal alignment regulating force has excellent heat resistance and transparency. The present invention provides a liquid crystal holding substrate with improved rubbing resistance, which does not impose any restrictions on the assembly of liquid crystal display elements.

Furthermore, a liquid crystal display device that is uncolored, stable over time, has a long life, and has high performance can be obtained.

The present invention provides a polyhydrazide acid-amide containing a silocane bond, which is obtained by providing an electrode on the side facing the liquid crystal on a liquid crystal sandwiching substrate, and reacting a carboxylic acid anhydride, dihydrazide, cyamine, and diaminosiloxane on the core substrate and the electrode. The present invention relates to a liquid crystal sandwiching substrate formed with a polyhydradiimide-siloxane polymer coating obtained by dehydrating and ring-closing an acid.

The siloxane bond-containing polyhydrasidic acid-amic acid, which is a precursor of the polyhydradiimide-siloxane polymer used in the present invention, is synthesized by the reaction of carboxylic acid anhydride, dihydrazide, diamine, and diaminosiloxane. These reactions are carried out under anhydrous conditions, preferably at temperatures of 30°C or lower. Regarding the reaction ratio of carboxylic anhydride, dihydrazide, diamine, and diaminosiloxane, it is preferable that the number of moles of carboxylic anhydride and the number of moles of dihydrazide, diamine, and diaminosiloxane be equimolar. This reaction involves dimethylformamide,
Dimethylacetamide, dimethyl sulfoxide.

This is carried out in the presence of a solvent such as N-methyl-2-pyrrolidone.

Examples of the carboxylic anhydride used in the present invention include pyromellitic anhydride, 2,3,6.7-naphthalenetetracarboxylic anhydride +11, a, 3;'4.4
'-Diphenyltetracarboxylic acid anhydride 1,1,2,5
．． 6-naphthalenetetracarboxylic anhydride, z′2:a
, a'-diphenyltetracarboxylic anhydride, thiophene-2,3,4,5-tetracarboxylic anhydride, 2.2
-bis(3,4-biscarboxyphenyl)propane m
Water elJ, 3.4-dicarboxyphenylsulfone anhydride, -! ! Rylene-3.4.9.10-tetracarboxylic anhydride, bis(3,4-dicarboxyphenyl)needle anhydride, 3.3. '4.4'-benzophenonetetracarboxylic acid anhydride and the like are used.

Examples of dihydrazide include isophthalic acid dihydrazide, terephthalic acid dihydrazide, 4゜4'-oxybis (benzoic acid hydrazide), 4,4'-sulfonyl bis (benzoic acid hydrazide), 3゜3'-sulfonyl bis (benzoic acid hydrazide). .

4.4'-Methylenebis(benzoic acid hydrazide).

4.4'-Carbonylbis(benzoic acid hydrazide).

4.4'-Biphenyl di(carbonyl hydrazide).

=5-4.4'-thiobis(benzoic acid hydrazide), oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide.

Adipic acid dihydrazide, pimelic acid dihydrazide, peric acid dihydrazide, azelaic acid dihydrazide, etc. are used.

Examples of diamine include m-phenylenediamine,
p-phenylenediamine, m-xylenediamine, p-
xylene diamine, 4.4'-diaminodiphenyl ether, 4.4'-diaminodiphenylmethane, a, a'
-dimethyl-4,4'-diaminodiphenylmethane,
a, a:s, 5'-tetramethyl-4,4'-diaminodiphenylmethane, 2,2'-bis(4-aminophenyl)propane-4,4'-methylene dianiline,
Benzidine, 4,4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfone, 1,5-diaminonaphthalene.

Examples of 3.3'-dimethylbenzidine, 3.3'-dimethoxybenzidine, and diaminomonoamide include 1
．． 4-diaminobenzene-2-carboxylic 6-amide, 4,4'-diaminodiphenylneedle-3-
Carbonamide and the like are used.

As the diaminosiloxane, for example, the general formula (wherein R is a divalent hydrocarbon group, R+, ltv,
几3 and R4 are monovalent hydrocarbon groups, and n is an integer of 1 or more. ) are used, examples of which include compounds such as.

For the carboxylic acid anhydride, dihydrazide, diamine, and diaminosiloxane, it is preferable to use aromatic compounds from the viewpoint of heat resistance. Two or more of each of carboxylic acid anhydride, dihydrazide, cyanogen, and diaminosiloxane d may be used in combination. There is no limit to the proportion of dihydrazide and diaminosiloxane contained in dihydrazide, diamine, and diaminosiloxane, but from the viewpoint of heat resistance, adhesion to the substrate, coloration and stability of the cured film, the proportion of dihydrazide, diamine, and diaminosiloxane contained in Wit is not limited. The dihydrazide is in the range of 50 to 95 molar ratio.

It is preferable to use diaminosiloxane in a range of 0.1 to 50 moles so that the total amount of the three components is 100 moles.

Application of the siloxane-bonded gold-containing polyhydrazidic acid-amic acid synthesized by the above reaction onto the substrate and electrodes is as follows:
iA' Siloxane binding polyhydrazidic acid-amic acid dimethylformamide, dimethylacetamide. This is carried out by applying a 0.01 to 40% by weight solution of dimethyl sulfoxide, N-methyl-2-pyrrolidone, etc., by a tip method, a spinner method, a spray method, a printing method, a brush coating method, or the like. 100℃~350℃ after coating,
Preferably, heat treatment is performed at 250°C to 300°C to dehydrate and ring-close the siloxane-bonded gold-containing polyhydrazidic acid-amic acid to obtain a polyhydradiimide-siloxane polymer coating 9
− It can be done.

Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples.

Dihydrazide 0.90 mol, p-phenylenediamine 0
,05 mol and 0.05 mol of 1,3-bis(aminopropyl)-tetramethyldisiloxane were dissolved.

Polyhydrazimide obtained by condensation with 1.0 mol of pyromellitic dianhydride at 10°C or lower - Siloxane bond-containing polyhydrazide acid which is a precursor of siloxane-based polymer
A 6% by weight solution of amic acid in N-methyl-2-pyrrolidone was applied using a spinner to a glass substrate on which indium oxide electrodes were formed. After coating, ring closure was performed by heating at 300'C for 1 hour to form a polyhydradiimide-siloxane polymer film having a thickness of 100 OA.

Thereafter, the coating was rubbed in a certain direction with gauze, but no peeling occurred in the polyhydradiimide siloxane 7-sane polymer coating. Furthermore, the coating had very little coloration and exhibited good visible light transmittance. Further, a liquid crystal display cell was prepared using a pair of substrates having the above-mentioned rubbed coating, and liquid crystal was sealed in the cell and the alignment was observed, and the alignment was found to be good.

Dissolve 0.7 mol of dihydrazide, 0.28 mol of 4.4'-diaminodiphenyl ether and 0.02 mol of 1.3-bis(γminobrovirone-tetramethyldisiloxane, and dissolve hyromellitic anhydride at 10°C or below. 0.5 mol and 3.3 mol of 4.4'-benzophenonetetracarboxylic acid anhydride and 0.5 mol of siloxane-bonded polyhydrazidic acid-amic acid obtained by condensation were prepared in the same manner as in Example 1. As a result of evaluation, a sandwiched substrate and display element with excellent rubbing resistance, visible light transmittance, and orientation heat resistance were obtained.

0.9 mol of isophthalic acid hashhydrazide and 0 p-phenylenediamine in N-methyl-2-pyrrolidone
．． Polyhydrazidic acid-imide acid, which is a precursor of polyhydradiimide obtained by dissolving 1 mol and condensing it with 1.0 mol of pyromellitic dianhydride at 10°C or lower, was evaluated in the same manner as in Example 1. However, the adhesion to the substrate was poor, and the film partially peeled off during rubbing.

727670.9 mol and 0.1 mol of 1,3-bis(aminopropyl)tetramethedisiloxane were dissolved, and 1
3. 0.5 mol of pyromellitic dianhydride and H below 0°C.
3: A siloxane bond-containing polyamic acid obtained by condensation with 0.5 mol of 4'-benzophenone tetracarboxylic anhydride was evaluated in the same manner as in Example 1. As a result, a sandwiched substrate and a display element with excellent rubbing resistance and orientation heat resistance were obtained, but these were very strongly colored.

As shown in the Examples and Comparative Examples, the polyhydradiimide-siloxane polymer coating of the present invention exhibits very excellent visible light transmittance. It also exhibits excellent adhesion to substrates and can withstand all types of rubbing treatment conditions. In addition, since the liquid crystal alignment regulating force has excellent heat resistance, the liquid crystal sandwiching substrate of the present invention does not impose any restrictions on the assembly of liquid crystal display elements, and is colorless, stable over time, has a long life, and has a high sieving performance. You can fatten the device.

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Claims (1)

[Claims] 1. An electrode is provided on the side facing the liquid crystal on a liquid crystal sandwiching substrate, and a carboxylic acid anhydride is provided on the substrate and the electrode. A liquid crystal sandwiching substrate formed by forming a polyhydradiimide-siloxane polymer film obtained by dehydrating a siloghisane-bonded gold-containing polyhydrazidic acid-amic acid obtained by reacting dihydrazide, diamine, and diaminosiloxane.