JPH03167523A - Liquid crystal holding substrate, production thereof and liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain liq. crystal holding substrates having high reliability by allowing a specified silicon compd. to react with >=5C alcohol in the presence of a catalyst, removing produced <=4C alcohol, carrying out hydrolysis and condensation, applying the resulting compsn. for forming silica films and forming oriented films on the formed insulating films. CONSTITUTION:A silicon compd. represented by formula I (where R' is 1-4C alkyl, R is 1-4C alkyl and/or acetyl and n is an integer of 0-3) is mixed with >=5C alcohol and/or alcohol deriv., a catalyst is added and they are heated. At this time, it is preferable that <=4C solvent produced by an exchange reaction is completely removed. Water is then added and hydrolysis and condensation are carried out. The resulting compsn. for forming silica films is applied and cured to form insulating films and oriented films are further formed on the insulating films. A low-cost liq. crystal display device having high reliability is obtd.

Description

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

(Prior art) Conventionally, regarding the manufacture of liquid crystal display elements. On a substrate with patterned transparent electrodes. After applying an alignment film made of an organic polymer such as polyimide and performing alignment treatment. A method of assembling elements was used. But in recent years. As liquid crystal display elements become larger, there are cases where the alignment film is scratched by foreign matter that gets into the alignment film's bottle holes or the element gaps.
Display defects due to conduction between the upper and lower substrates caused by the break-through 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, such as (1) forming an oxide film at a low temperature by sputtering, (2) using alkoxysilane, alkoxytitanium, and thickening. After applying a solution containing an organic compound as an agent using a printing method, etc. Methods such as heat treatment to form an oxide film are employed.

however. In method (1). It required expensive vacuum equipment and had the disadvantage of poor productivity due to batch processing. As method 1 and (2), conventional method. Halogenated silane. The method of coating a solution of alkoxysilane or its partially hydrolyzed product on a substrate and baking it to form a silica-based film is well known.
Publication No. 52-20825, Japanese Unexamined Patent Publication No. 1982
This method has been proposed in, for example, Japanese Patent No.-34258. However, with the method using halogenated silanes, hydrogen halides are generated by hydrolysis. Controlling the reaction is extremely difficult because the system becomes strongly acidic. A large amount of hydrogen halide remains in the product, which impairs the stability of the liquid, and when used in liquid crystal display devices, etc. It has the disadvantage that the moisture resistance reliability of the element is significantly reduced (7).On the other hand, as alkoxysilane, conventional
The following alkoxysilanes have been used. In these systems, alcohols with carbon numbers of 4 or less and katap alcohol derivatives form a raw bottom after the hydrolysis reaction, so the viscosity of the liquid is low. 1) Application by printing method could not be carried out without adding a thickener, which increases volatility. As a way to improve this. Possible methods include a method using an alkoxysilane having an alkoxy group with a carbon number of 5 or more, and a method in which alcohol with a carbon number of 4 or less produced after hydrolysis with an alkoxysilane with a carbon number of 4 or less is removed under reduced pressure. .

However, the former is because alkoxysilane compounds with 5 or more carbon atoms have extremely high boiling points. It has the disadvantage that it is difficult to produce, and in the case of the latter, when the alcohol is removed, the hydrolyzate condenses and becomes high in molecular weight. It has been difficult to put this into practical use due to the drawback of significantly reduced liquid stability.

(Problem to be solved by the invention) The present invention. This product has a high viscosity that can be coated by printing method and improves the shortcomings of these conventional technologies. A protective film with excellent insulation properties is formed on the transparent electrode using a low-volatile silica-based coating liquid. The purpose of this invention is to easily obtain a highly reliable liquid crystal holding substrate, a button manufactured using the same, and a liquid crystal display element using the same.

(Means for Solving Problem Ill) In other words, the present invention provides a structure in which the general formula A is formed on a substrate having a transparent electrode.
) R'n Si(OR)4-n
A) (In the formula, R' is an alkyl group having 1 to 4 carbon atoms.R is an alkyl group having 1 to 4 carbon atoms and /1 or an acetyl group.n
represents an integer from 0 to 3). An alcohol having 5 or more carbon atoms and/or a derivative of Kakitapaso are reacted in the presence of a catalyst. After removing the produced alcohol and/or its derivatives having 4 or less carbon atoms from the system. The above general formula A used for producing the coating liquid for forming a silica-based film of the present invention, in which an insulating film is formed by coating and curing a silica-based film-forming composition obtained by adding water and hydrolyzing and condensing the composition. ) is a silicon compound represented by. Tetramethoxysilane, tetraethoxysilane.
Tetraalkoxysilanes such as tetraboxysilane and tetraptoxysilane, and methyltrimethoxysilane. Ethyltriethoxysilane. Alkyltrialkoxysilanes such as methyltriisoproboxysilane and methyltributoxysilane. Dimethyldimethoxylane, dimethyldiethoxysilane. Diethyl diisoproboxylene. Two or more types of dialkyldialcoquine 7ranes such as diethyldibutoxysilane, alkylacetoxysilanes such as tetraacetoxysilane, methyltriacetoxysilane, ethyltriacetoxysilane, and dimethyldiacetoxysilane are used.

It was a cabinet. Examples of alcohols having 5 or more carbon atoms and their derivatives include ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, ethylene glycol in amyl ether, and propylene glycol monopropyl ether. ether. Probylene glycol monobutyl ether. Propylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol heptanoethyl ether. Diethylene glycol monophthyl ether. cyethylene glycol monobrobyl ether,
-Al fluoride of compounds such as diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobrobyl ether, hexylene glycol, 17 ethylene glycol, etc. Two or more types are used.

The alcohol having 5 or more carbon atoms and/or its derivative preferably has a viscosity of 3 centivoise or more at 20° C. in order to improve printability. If this viscosity is less than 3 centipoise, repellency is likely to occur during printing and coating. 1,
In order to prevent the composition from drying out on the substrate, the alcohol having 5 or more carbon atoms and/or its derivatives should have a boiling point of 1 at normal pressure.
Preferably, the temperature is 00°C or higher. Boiling point is 100 at normal pressure
Below ℃. Foreign matter adhesion due to the formation of dry matter on the substrate.
Changes in coating film thickness due to changes in the solubility of the composition are likely to occur. It's a good shelter. It is an alcohol with 5 or more carbon atoms and a viscosity of 3 centiboise or more at 20°C and a boiling point of 100°C or more at normal pressure.

When producing the coating solution for forming a silica-based film of the present invention, the catalysts used for the transesterification reaction include nitric acid, sulfuric acid,
Inorganic acids such as phosphoric acid and organic acids such as oxalic acid, maleic acid, and acetic acid are used. It is not limited to these.

Next, in the production of the coating liquid for forming a silica-based film of the present invention, the reaction method is as follows:
Mix the above alcohol and/or alcohol derivative. Add catalyst and heat. At this time, the amount of alcohol and /''!! or alcohol derivative added should be preferably <d2 times equivalent or more with respect to the substitutable alkoxy group and/or alkyl ester group of the silicon compound. The amount of the catalyst to be added is preferably 0.1 to 2 times more by weight than the silicon compound mentioned above.The reaction temperature is set at an alcohol with 4 or less carbon atoms that can be produced by exchange reaction. In order to remove the alcohol derivatives from the system.The temperature is preferably higher than their boiling points.The solvent having 4 or less carbon atoms formed as a raw bottom by the above exchange reaction must be completely removed. Although it is preferable that it remains in the coating solution obtained after hydrolysis, it may remain in the range that does not reduce the viscosity of the coating solution to 10 centipoise or less.

After the exchange reaction, water and other solvents are added as necessary to perform hydrolysis and condensation. On this occasion. The amount of water to be added is equivalent to the hydrolyzable group of the silicon compound, or 80 to 80% thereof.
100 equivalents are preferred.

Although there is no particular restriction on the reaction temperature of the hydrolysis reaction, it is preferable to heat it to 50 to 100°C to accelerate the reaction. As other solvents that may be added as necessary, the aforementioned solvents having 5 or more carbon atoms are preferred.

The liquid crystal holding substrate of the present invention is. After applying the above-mentioned composition for forming a silica-based film onto a substrate on which a pattern of transparent electrodes has been formed using a printing machine such as a roll coater or a blade coater, it is heated to a temperature of 100 to 200°C. Dry at a temperature of 120 to 180°C. 200~500℃ preferably 300~4
It is obtained by curing at a temperature of 00° C. to form a silica-based film, and applying a resin for alignment film thereon and curing it. At this time, it is preferable that the film thickness of the silicate film is 500 to 2000 A.

If it is thinner than 500A, the effect of preventing poor conduction cannot be obtained sufficiently, and if it is thicker than 2000A, the alignment characteristics will deteriorate.

As a resin for alignment film. Polyimide, polyamideimide. Polyimide resins such as polyetherimide and polyesterimide are suitable, but other resins such as polyvinyl alcohol and polyvinyl acetal are also suitable. Various film-forming polymeric resins can also be used.

The liquid crystal holding substrate of the present invention is produced by wrapping an alignment film using a known method, then sealing with a sealant containing a gap material dispersed therein, and then injecting liquid crystal. It is sealed to form a liquid crystal display element.

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

Example 1 A) Preparation of silica-based film forming composition Thermometer. 5. Tetraethoxysilane in a four-loop flask equipped with a condenser and a stirrer with a flow divider 2. 1
g, Heki'/Re7f Recall 29 6.4 9 + 0.6 g of phosphoric acid was charged and heated to 100° C. using an oil bath while stirring. After about 1 hour, reflux of ethyl alcohol occurred in the separation tube, and when the reflux temperature reached about 80°C, recovery of ethyl alcohol was started. 5 hours later.
When 45 g of ethyl alcohol was recovered, gas chromatography measurements confirmed the disappearance of tetraethoxysilane and the formation of a reaction product of hexylene glycol.

Next, the reaction solution was cooled to room temperature 1. Ion exchange water 17.69
After dripping. The mixture was reacted at 60° C. for 5 hours to obtain a silica-based film forming composition. The concentration of the composition thus obtained is 2
Measured as drying residual at 00°C/2 hours. 5.
It was 0 weight i1%. The viscosity of the casing was measured at 25°C using an Ubbelohde viscometer, and it was found to be 30 centistokes (
0. 3 cm”/sl.

B) Fabrication and evaluation of liquid crystal holding substrate 3 with a transparent electrode pattern of 640 x 200 dots
On a glass substrate of 00 x 150 mm, a silica-based coating formed from Al was applied using a roll coater.
After drying at 150°C for 1 hour. It was cured at 300° C. for 1 hour to form a silica-based film.

The thickness of the obtained film was measured using Talystep (manufactured by Rank Taylor Hobson) and was found to be IIOOA. No defects such as cissing were observed.

Next, use the roll coater again on the film. Boimide liquid crystal alignment film material LQ-1800 (manufactured by Hitachi Chemical Co., Ltd., resin concentration 7% by weight) was applied. After drying at 150°C for 30 minutes. The film was cured at 300° C. for 1 hour to form a soo'k alignment film, and a liquid crystal holding substrate was obtained.

The thus obtained shielding crystal holding substrate was rubbed by a conventionally known method. They were laminated with epoxy resin EN-1000 (manufactured by Hitachi Chemical Co., Ltd.) in a 210' twist, and a liquid crystal ZLI-1132 (manufactured by Merck & Co., Ltd.!!!) was sealed to prepare a liquid crystal display cell. Next, power is applied to the liquid crystal display cell using a DC power source. Apply pressure. The orientation state at that time was visually observed. the result. No alignment defects due to conduction between the upper and lower substrates were observed.

(Effect of the invention) According to the present invention. A liquid crystal holding substrate on which a silica-based insulating film is formed can also be easily obtained by a printing method.

Therefore, by using the liquid crystal holding substrate obtained in this way. It becomes possible to manufacture inexpensive and highly reliable liquid crystal display elements.

Claims (1)

[Claims] 1. On a substrate having a transparent electrode, the general formula A) R'_nSi(OR)_4_-_nA) (wherein R' is an alkyl group having 1 to 4 carbon atoms, and R is an alkyl group having 1 carbon number)
-4 alkyl groups and/or acetyl groups, n is 0-3
(representing an integer of A composition for liquid crystal display elements in which an insulating film is formed by applying and curing a silica-based film-forming composition obtained by adding water, hydrolyzing and condensing, and then forming an alignment film thereon. LCD holding board. 2. The method for producing a liquid crystal holding substrate according to claim 1, wherein the silica film-forming composition according to claim 1 is applied by a printing method onto a substrate having a transparent electrode. 3. A liquid crystal holding substrate for a liquid crystal display element according to claim 1, wherein the alignment film is a polyimide alignment film. 4. A liquid crystal sandwiching method in which the composition for forming a silica-based film according to claim 1 is coated and cured by a printing method on a substrate having a transparent electrode to form an insulating film, and then a polyimide-based alignment film is formed thereon. Substrate manufacturing method. 5. A liquid crystal display element obtained using the liquid crystal holding substrate according to claim 1.