JPH02105881A - Composition for insulating substrate for sandwiching liquid crystal, substrate for sandwiching liquid crystal, production of the same substrate, and liquid crystal display element - Google Patents

Abstract

PURPOSE:To make it possible to form a composition for an insulating substrate for sandwiching a liquid crystal, which can form an excellent insulating protective film for a transparent electrode when cured and which can be cured by heat treatment at low temperatures, by dissolving a specified hydroxy-terminated ladder polysiloxane and a specified organometallic compound in a solvent. CONSTITUTION:This composition comprises hydroxy-terminated ladder polysiloxane (a) of formula I (wherein R1 and R2 are each a hydrogen atom or a monovalent hydrocarbon group; and n is a positive integer), an organometallic compound (b) of the general formula: M(OR')m (wherein M is a metallic element; R' is a hydrogen atom or a monovalent hydrocarbon group; and m is a positive integer) and a solvent (c). Component (a) is preferably one having a number-average MW in the range of 1000-500000 and contained in an amount of 5-20wt.% in the composition. Examples of component (b) include Si(OR')4, Ti(OR')4, Zr(OR')4, Ta(OR')5 and In(OR')3 and when they are used chiefly as crosslinking agents, they are added in an amount of 10-100mol% based on the hydroxyl concentration of component (a).

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a liquid crystal sandwiching substrate insulating composition for producing a liquid crystal sandwiching substrate that improves display defects caused by conduction between the upper and lower substrates of a liquid crystal display element, and The present invention relates to a liquid crystal sandwiching substrate, a method for manufacturing the same, and a liquid crystal display element.

(Prior Art) Conventionally, when manufacturing a liquid crystal display element, an alignment film made of an organic polymer such as polyimide is coated on a substrate having a patterned transparent electrode.

A method has been used in which the device is assembled after alignment treatment. However, in recent years, as liquid crystal display elements have become larger, foreign matter that has entered pinholes in the alignment film or gaps between the elements has caused damage to the alignment film.

Display defects due to conduction between the upper and lower substrates caused by puncturing have become a problem.

Recently, as a means to solve this problem, methods of forming an insulating layer between the transparent electrode and the alignment film have been studied.2For example, (1) forming an oxide film at low temperature by sputtering, (2) A method has been adopted in which a solution containing silane, alkoxytitanium, and an organic polymer as a thickener is applied by a printing method, and then heat-treated to form an oxide film.

However, method (1) requires expensive vacuum equipment, has poor productivity due to batch processing, and (
Method 2) requires high-temperature treatment to form an oxide film, and this high-temperature treatment has drawbacks such as an increase in the sheet resistance of the transparent electrode.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned drawbacks of the prior art, and after coating by a printing method or the like, it is cured by heat treatment at a low temperature that does not increase the sheet resistance value of the transparent electrode, and becomes insulating. The present invention provides a composition for insulating a liquid crystal holding substrate that forms a protective film with excellent properties, a liquid crystal holding substrate using the same, a method for manufacturing the same, and a liquid crystal display element.

(Means for Solving the Problems) As a result of intensive studies, the present inventors have found that a composition in which #-terminated hydroxyl ladder polysiloxane and a specific organometallic compound are dissolved in a solvent is cured by low-temperature heat treatment. Found that it forms an excellent insulating protective film for transparent electrodes 2
We have arrived at the present invention.

That is, 1 the present invention is based on (a) the general formula (where 几! and mount are hydrogen or a monovalent hydrocarbon group 9m
is a positive integer), (b) general formula % formula % () (in the formula, 1M is a metal element, R' is hydrogen or a monovalent hydrocarbon group 9m is a positive integer) A composition for insulating a liquid crystal holding substrate containing an organometallic compound represented by the following formula and (C) a solvent, a liquid crystal holding substrate containing this insulating composition, a method for manufacturing the liquid crystal holding substrate, and a liquid crystal holding substrate. The present invention relates to a liquid crystal display device using a substrate.

The terminal hydroxy ladder polysiloxane represented by the general formula (1) used in the liquid crystal holding substrate of the present invention is, for example, phenyltrichlorosilane as shown in Japanese Patent Publication No. 58-50657.

After hydrolysis using a large amount of water, the resulting hydrolyzate is subjected to dehydration condensation polymerization in toluene using carbodiimides as a catalyst. In this case, 几 1 and uma in the general formula (1) are phenyl groups, but in the present invention, in addition to these, alkyl groups such as methyl group and ethyl group, allyl groups such as chlorophenyl group, etc. It can be a monovalent hydrocarbon group and hydrogen, and these can contain 2 or more 1s'' in the molecule. These terminal hydroxyl ladder polysiloxanes can also be used as a mixture.

The number average molecular weight of the terminal hydroxyl ladder polysiloxane is from 1,000 to 1,000 in terms of viscosity and curability as a coating liquid.
A range of 500,000 is preferred, more preferably a range of 0.
The range is from 00 to so, o o o. Although the concentration of the terminal hydroxyl ladder polysiloxane varies depending on its molecular weight and coating film thickness, it is preferably 5 to 20% by weight based on the composition for insulating liquid crystal sandwiching substrates.

The organometallic compound represented by the general formula (II) used in the present invention and the organometallic compound used in the present invention, Sj (OR')41
Ti (OR')4 *Zr(Q几')41 Ta(
OR')s* Compounds such as In(OR')s, specifically tetraisopropoxytitanium.

Examples include tetrabutoxyzirconium, tetraethoxyzirconium, pentaethoxytantalum, triptoxyindium, and the like. These compounds react with the terminal hydroxyl ladder polysiloxane terminal hydroxyl group to form Si.
It forms a -0-M bond and acts as a crosslinking agent at low temperatures. Further, depending on the amount added, the refractive index of the protective film to be formed can be controlled, and phenomena such as so-called Nesa black, in which the transparent electrode pattern is visible when not lit, can be prevented. When used mainly as a crosslinking agent, the amount of these organometallic compounds added is 10 to 100% relative to the hydroxyl group concentration of the terminal hydroxyl ladder polysiloxane.
A molar ratio is preferable, and when the main purpose is to control the refractive index, it is preferable to use an organometallic compound such as titanium or zirconium, and set the ratio of metal atoms to Si atoms to be 10 to 100 molar.

The insulating composition for liquid crystal sandwiching substrates of the present invention can be obtained by dissolving the above-mentioned terminal hydroxy ladder polysiloxane in a solvent at room temperature or higher temperature, then adding a predetermined amount of the above-mentioned organometallic compound, and dissolving with stirring. can get. The solvent used in this case is I NlN-dimethylacetamide, N
-Methyl-2-pyrrolidone, bunal cellosolve, hexylene glycol, butyl cellosolve acetate, etc. are used.

The liquid crystal holding substrate of the present invention is produced by applying the above-mentioned insulating composition onto a substrate on which a pattern of transparent electrodes is formed using a printing machine such as a roll coater, a spinner coating machine, etc.
It is obtained by forming an insulating protective film of a transparent electrode by heat treatment at 300° C., preferably 150 to 250° C., on an open or hot plate, and then forming an alignment film thereon by a known method.

The heat treatment time for the above-mentioned insulating protective film is preferably about 30 to 90 minutes in the case of an oven, and about 10 to 30 minutes in the case of a hot grate.

Further, the thickness of the insulating protective film to be formed is preferably 500 to 2000 A from the viewpoint of dielectric strength.

The liquid crystal holding substrate of the present invention is made into a liquid crystal display element by rubbing the alignment film using a known method, then bonding the substrates with a sealing material in which a gap material is dispersed, and injecting and sealing the liquid crystal.

(Example) The present invention will be explained below with reference to nine examples.

Example I A) Synthesis of terminal hydroxyl ladder polysiloxane Phenyltrichlorosilane (CgHsSiC1!s) 105
．． 89 (0.5 mol) in diethyl ether 200 m/
dissolved in On the other hand, 11 ion-exchanged water in 21 Yotsuro flasks! A stirrer, a cooler, and a thermometer were attached to the flask, and the flask was cooled to below 20°C in a water bath.The ether solution of phenyltrichlorosilane was added dropwise into the flask from the dropping funnel to perform hydrolysis. The reaction temperature is 20℃ or less, and
The dripping was completed in an hour. Stirring was stopped, the reaction solution separated into two layers was put into a separating funnel, and the ether layer was taken out. After washing the ether layer with deionized water until it becomes neutral.

The mixture was dried with anhydrous sulfuric acid (IJum) for 1 day. Thereafter, the ether was removed, and the mixture was placed in a vacuum dryer and dried at 60° C. for 2 hours. 350 in the obtained white powder aI process spectrum.
Absorption of 10H at 0cm-1, 1130°1135cm-
The absorption of IK8i-o-8i was shown. Its number average molecular weight was about 1.000.

Next, the white powder hydrolyzate was weighed into a three-meter flask equipped with a reflux condenser stirrer and a thermometer, and 30 mI of toluene was added as a solvent. was added and dissolved to form a uniform layer. Dicyclohexylcarbodiimide ttg was added as a condensation catalyst and dissolved therein, and the mixture was reacted at 110° C. under stirring and reflux for 2 hours. After the reaction, precipitation of urea derivatives was observed in the two reaction vessels. After the reaction was completed, the reaction mixture was allowed to cool.

The urea derivative was suction filtered, poured into 10 times the volume of methanol to precipitate the polymer, and then filtered.

Dry under reduced pressure. The number average molecular weight of the obtained polymer was 50
．． OOO, -1 and its El spectrum has 3
Absorption due to -○H was observed at 500 cm-'', confirming that it was a terminal hydroxy polyphenyl ladder polysiloxane.

B) Preparation of composition for insulating liquid crystal holding substrate 5 g of the terminal hydroxy polyphenyl ladder siloxane obtained above was
Weighed into a four-way flask equipped with a reflux condenser, stirrer, thermometer and dropping funnel, added 60G of N,N-dimethylacetamide as the solvent! :Hexylene glycol 30g
was added and stirred to dissolve. Next, 5 g of a 10% by weight isopropyl alcohol solution of tetraisopropoxytitanium was added dropwise from the dropping funnel with stirring, and the mixture was stirred and mixed at room temperature for about 2 hours to obtain a composition for insulating a liquid crystal sandwiching substrate.

The concentration of the obtained composition was 5.1% by weight (200°C/2h
(dry), and the viscosity at 25° C. was 40 centivoise.

The obtained composition was applied onto a silicon wafer using a spinner, heat treated at 150°C for 1 hour, and then heated for 30°C.
Heat treatment was performed at 0° C. for 1 hour to form a film with a thickness of zoooA. 2 mm to the coating.

Al! When electrodes were deposited and the dielectric breakdown voltage was measured,
It showed a withstand pressure of about 1oov.

C) Preparation and evaluation of liquid crystal sandwiching substrate 3 A transparent electrode pattern of 640 x 200 dots was formed.
After applying the above composition on a glass substrate of 0.00 x 150 mm by printing method, heat treatment similar to that described above was performed, and a thickness of 100 mm was applied.
An insulating protective film of 0^ was formed.

Next, a polyimide alignment film material (Hitachi Chemical Co., Ltd. splitting product name LQ-1800) was applied on the film using the same printing method.
Heat treated at 150°C for 1 hour and then further heated.

A heat treatment was performed at 300° C. for 1 hour to form an alignment film of approximately 800 mm, thereby obtaining a liquid crystal sandwiching substrate.

The thus obtained liquid crystal sandwiching substrate was rubbed using a known method, and the epoxy sealant EN was applied so that it was twisted by 210 degrees.
-1000 (made by Hitachi Chemical ■) with #'i, 9 combination,
A liquid crystal display cell was prepared by enclosing a liquid crystal ZLI-1132 (manufactured by Merck & Co.), and a DC 1! A voltage was applied using a source, and the orientation state at that time was visually observed. As a result, no alignment defects or Nesa black due to conduction between the upper and lower substrates were observed. Furthermore, when the driving voltage was measured on the DC power source side, there was no increase in the driving voltage due to an increase in the resistance of the transparent electrode.

Example 2 Terminated hydroxypolyladder siloxane G-100 (Owens Illinois Co., Ltd.) having methyl groups and phenyl groups in the side chains in a ratio of 2:1 was weighed in a flask similar to Example 1. 559 N-methyl-2-pyrrolidone and 30 g of butyl cellosolve were added as a solvent and dissolved with stirring. moreover.

After dropping 5 g of a 5% by weight solution of tetrabutoxyzirconium in butyl selon from the dropping funnel while stirring, the mixture was stirred and mixed at room temperature for about 2 hours to obtain a composition for insulating a liquid crystal sandwiching substrate. The concentration of the resulting composition was 9.8% by weight, and the viscosity was 20%.
It was centiboise.

The dielectric strength voltage of the insulating protective film obtained using this composition was evaluated in the same manner as in Example IB) and was found to be 45V/100.
It was 0X.

In addition, the protective film-forming insulating composition thus obtained was coated by a printing method on a glass substrate similar to that in Example IC), and then heat-treated at 150°C for 1 hour and then at 250°C for 1 hour to determine the thickness. A 1000-sized insulating protective film is formed, and furthermore, on the film, Hitachi Chemical Co., Ltd.
A polyimide-based alignment film of approximately 5001 was formed using the same method to prepare a liquid crystal holding substrate.

A liquid crystal display cell was produced in the same manner as in Example 1 using the liquid crystal holding substrate obtained in this way, and the alignment state under pressure was observed. As a result, conductivity was poor and Nesa black was observed.

The results were good with no change in driving voltage.

(Effects of the Invention) The composition for insulating a liquid crystal holding substrate of the present invention can form an insulating protective film for a transparent electrode by a coating method and a curing treatment at a low temperature, and the liquid crystal holding substrate obtained using the composition is inexpensive. It has the advantages of high resistance, low resistance, and no blackness, which makes it possible to manufacture high-quality liquid crystal display elements with no conduction defects between the upper and lower substrates at low cost.

Claims (4)

[Claims] 1. (a) General formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (I) (In the formula, R_1 and R_2 are hydrogen or monovalent hydrocarbon groups, and n represents a positive integer) Terminal hydroxy ladder polysiloxane , (b) an organometallic compound represented by the general formula M(OR')_m(II) (wherein M is a metal element, R' is hydrogen or a monovalent hydrocarbon group, and m is a positive integer); and (c) A composition for insulating a liquid crystal holding substrate containing a solvent. 2. A liquid crystal holding substrate comprising an alignment film formed on a cured film of the liquid crystal holding substrate composition according to claim 1 on a substrate having a transparent electrode. 3. A method for manufacturing a liquid crystal holding substrate, comprising applying and curing the composition for a liquid crystal holding substrate according to claim 1 on a substrate having a transparent electrode, and forming an alignment film thereon. 4. A liquid crystal display element using the liquid crystal holding substrate according to claim 2.