JPH0363629A - Spacer for liquid crystal and production thereof - Google Patents

Abstract

PURPOSE:To improve gap accuracy by providing an exposed metal oxide layer on the surface of solid fine particles. CONSTITUTION:The spacers for a liquid crystal are formed by providing the exposed titanium oxide layer on the surface of the solid fine particles. Resins, such as polyethylene and polypropylene/divinyl benzene copolymer, having a network structure are used as the material of the solid fine particles. A film obtd. by treating a silane coupling agent is provided on the surface of the solid fine particles and after the particles are immersed into a treating liquid contg. an org. titanate compd., the solvent is evaporated, by which the titanium oxide layer is formed on the surface of the fine particles. Since the alkyl group derived from the org. titanate is incorporated into the titanium oxide layer, the spacer surface is hydrophobic. The flocculation of the spacers to each other is, therefore, extremely hardly caused and the dispersibility of the spacers is improved at the time of dispersing the spacers on glass substrates. The gap accuracy of the liquid crystal cell is, therefore, greatly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a liquid crystal spacer used in a liquid crystal display device and a method for manufacturing the same, and more particularly to a liquid crystal spacer with extremely excellent dispersibility and a method for manufacturing the same.

(Prior Art) A liquid crystal spacer is disposed between a pair of glass substrates and is used to maintain a constant gap between the pair of glass substrates. Since the gap needs to be kept constant in the plane direction of the glass substrate, the liquid crystal spacers are arranged at a predetermined distance from each other.

However, in general, this type of fine liquid crystal spacers tend to aggregate with each other, and several to ten liquid crystal spacers tend to aggregate to form a lump. If the liquid crystal spacers are placed between the glass substrates in a cohesive state as described above, the gap accuracy will deteriorate, especially in a transmissive liquid crystal cell for monochrome display.
Since the agglomerated portion usually appears white, the black and white display contrast is reduced.

Conventionally, in order to improve the dispersibility of liquid crystal spacers, for example, Japanese Patent Application Laid-Open No. 62-195623 discloses a method of improving the dispersibility by irradiating ultrasonic waves. However, this method requires special equipment and uses ultrasonic waves, making it extremely impractical from an industrial perspective.

Although it is obvious that the most direct and effective method is to process the liquid crystal spacers themselves to prevent mutual agglomeration, and that it is industrially advantageous, specific means for this purpose have been proposed in the prior art. It has not been.

(Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned circumstances, and by improving the dispersibility of the liquid crystal spacer, the gap accuracy of the liquid crystal cell can be significantly improved. Another object of the present invention is to provide a liquid crystal spacer and a method for manufacturing the same, in which the decrease in the contrast of a liquid crystal display is significantly reduced and furthermore, minute spots due to aggregation of the spacers do not appear on a liquid crystal display screen.

(Means for Solving the Problems) The liquid crystal spacer of the present invention is characterized in that an exposed titanium oxide layer is provided on the surface of solid particles, thereby achieving the above object. Another liquid crystal spacer of the present invention is characterized in that a film obtained by treating the surface of solid fine particles with a silane coupling agent is provided, and an exposed titanium oxide layer is provided on the surface of the film. , thereby achieving the above objective.

The method for manufacturing a liquid crystal spacer of the present invention is characterized by treating solid fine particles with a silane coupling agent to form a film, and then treating the solid fine particles on which the film has been formed with an organic titanate compound. The above objective is achieved.

Examples of the material and shape of the solid fine particles used in the present invention include those shown below.

[Material]

polyethylene, polypropylene, polymethylpentene,
Linear or crosslinked polymers such as polyvinyl chloride, polytetrafluoroethylene, polystyrene, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, boria oxide, polyimide, polysulfone, polyphenylene oxide, polyacetal; epoxy resin, phenolic resin, Melamine resin, unsaturated polyester resin, divinylbenzene polymer, divinylbenzene-styrene copolymer, divinylbenzene-acrylic acid ester copolymer 5, diallyl phthalate polymer, triallyl isocyanurate polymer, benzogeanamide polymer, etc. A resin with a wire structure. Among the solid fine particles, particularly preferred are dizenylbenzene copolymer,
These resins have a wire structure such as divinylbenzene-styrene copolymer, divinylbenzene-acrylic acid ester copolymer, diallyl phthalate polymer, etc.

Inorganic materials include silicate glass, borosilicate glass,
Lead glass, soda lime glass, aluminum glass.

Alumina silicade or the like can be used. Among these, particularly preferred is silicate glass.

It is borosilicate glass.

〔shape〕

The shape of the solid fine particles is not limited, however.

For example, a true sphere, an elliptical sphere, or a nine-cylindrical shape having the dimensions shown below can be used.

In the case of true spherical solid particles, the diameter is 0.1μ+m~10
It is preferably in the range of 00μ-, and a particularly preferable range is 1
μ11 to 100 μ−.

In the case of ellipsoidal solid particles, the minor axis is 0.1 μm-1
000 μm, and a particularly preferred range is 1 am to 100 μm. The ratio of major axis to minor axis is 1 to 1
The range is preferably 0, and the particularly preferred range is 1-5.

In the case of cylindrical solid particles, the diameter is 0.5 μl11-1
The thickness is preferably in the range of 000μ-, and a particularly preferred range is 3μ steel to 100μ steel. The length to diameter ratio of a cylinder is 1
The range is preferably from 1 to 50, particularly preferably from 1 to 50.
The range is 10.

There is one method for treating these solid fine particles with an organic titanate compound, for example, as shown below.

(2) Solid particles are immersed in a treatment solution containing an organic titanate compound, the treatment solution is filtered off, and then dried.

(2) A treatment solution containing an organic titanate compound is sprayed or applied onto solid particles, and then dried.

The solvent for the treatment liquid is 2, for example, n-hexane, dichlorohexane, benzene, toluene, or trichlene.

Examples include Freon-133.

In method (2), an organic titanate compound is dissolved in a solvent, and solid fine particles are immersed in the solvent.

A method of evaporating the solvent while thoroughly mixing is preferred. After evaporating the solvent, it is preferable to heat at 60°C to 100°C, but 1 this heating step may be omitted.

In method (2) above, solid particles are spread out on a glass plate, metal plate, etc.

It is also possible to apply the treatment liquid using a spray gun or the like. After coating, heat treatment may be performed under the above-mentioned heating conditions.

Examples of organic titanate compounds used in the present invention include 5, for example, tetraethoxytitanium Ti (OCJs), 41 tetrapropoxytitanium Ti (OCJy) a, and tetrabutoxytitanium Ti (OC4H9) 4. Tetrapentoxytitanium Ti (OCsH+ 1)4. Tetrahexoxytitanium Ti (OCJ+z) 4°tetrakis(2-ethylhexoxy)titanium Ti (OCHzC
H(CJs)CJv) a, tetradodecyl alkoxytitanium Ti(QC,zH□)1. Tetrastearoxytitanium Ti (OC+ dhs) sr Dipropoxy bis(acetylacetonato)titanium (OCJt)
z (QC・(CH:l) CHCOCH3) z, dibutoxy bis(triethanola ξnato) titanium Ti
(OCJw)! (OC!HJ(CzH40H) z
) t.

Dividroxy bis(lactato)titanium (OH)
t(OCH(CHs) C-008) z, titanium propoxyoctylene glycole) Ti (
OCfbCH(CJs)CH(C+To)OH]4, etc. are used, and among the above, particularly preferred are tetrapropoxytitanium, tetrabutoxytitanium, tetrakis(2-ethylhexoxy)titanium, and dipropoxy bis(acetylacenato)titanium. , dibutoxy bis(triethanolaminate) titanium.

(Left below) The organic titanate compound treated on the surface of the solid fine particles in the above steps reacts with moisture in the air in an exposed state and is hydrolyzed to form a titanium oxide with the structure shown below. It seems to form a layer.

The amount of the titanium oxide layer formed in the form of a thin film on the surface of the solid fine particles is preferably set in the range of 0.01 to 500 square meters per surface area of the solid fine particles, expressed as titanium equivalent weight. A more preferable amount of titanium oxide layer is 0.1■
~100■. If the amount of titanium oxide is less than 0.01 square centimeters per liter of surface area of the solid particles in terms of titanium weight, the effect of preventing agglomeration of the liquid crystal spacer will be small. On the other hand, if the amount of the titanium oxide layer is more than 500 .mu.m per surface area of the solid particles in terms of titanium weight, unfavorable results such as a decrease in electrical resistance will occur.

In addition, in the present invention, in order to improve the adhesion between the solid fine particles and the titanium oxide layer, the solid fine particles are treated with a silane coupling agent in advance to form a coating, and the solid fine particles on which this coating is formed are transferred to the titanium oxide layer. It may be treated with an organic titanate compound as in

The operation for treating solid fine particles with a silane coupling agent is as follows.

(2) Immerse solid particles in a treatment solution containing a silane coupling agent, filter the treatment solution, and then dry the solid particles.

(2) After spraying or applying a treatment liquid containing a silane coupling agent to solid particles, drying is performed.

In the method (2) above, the conditions such as the concentration of the treatment liquid, treatment temperature, treatment time, etc. are as follows, for example. 1 part by weight of solid fine particles to 1 to 1000 parts by weight of a suitable dispersion medium (described later),
It is preferably dispersed in 5 to 500 parts by weight, and 0.001 to 1 part by weight of a silane coupling agent, preferably o,
Add ~0.3 parts by weight of oos.

After stirring at room temperature for 10 minutes to 12 hours, preferably 30 minutes to 6 hours, the dispersion medium is separated from the furnace, and the remaining solid particles are heated at 40°C.
~500''C1 Preferably heated at 60°C to 400°C for 15 minutes to 12 hours, preferably 30 minutes to 5 hours.

In method (2) above, solid particles are spread out on a glass plate, metal plate, etc.

It is also possible to apply the treatment liquid using a spray gun or the like. After coating, heat treatment may be performed under the above-mentioned heating conditions.

Examples of the silane coupling agent used in the present invention include the following.

■Vinyl-based vinyltriethoxysilane, vinyl-tris(2-methoxyethoxy)silane ■Methacryl-based gamma-methacryloxypropyltrimethoxysilane ■Amine-based gamma-aminopropyltrimethoxysilane.

N-beta(ami))ethyl-gamma-aminopropyl-trimethoxysilane, 3-[N-allyl-N(2-
aminoethyl) core aminopropyltrimethoxysilane,
3-(N-allyl-N-methacryl)aminopropyltrimethoxysilane, 3-(N,N-diglycidyl)aminopropyltrimethoxysilane■Amine-based N,N-bis[(methyldimethoxysilyl)propylcorerane, N,N-bis[3-(trimethylsilyl)propyl]amine, N,N-bis[3-(methyldimethoxysilyl)propyl]ethylenecyagon Propyl]
Methacrylamide ξ-do, N, N-bis[3-(trimethoxysilyl)propyl]methacrylamide ■Glycidyl-based gamma-glycidoxypropyltrimethoxysilane, N
-Glycidyl-N,N-bis[3-(trimethoxysilyl)propyl]amine ■Mercapto-based gamma-mercaptopropyltrimethoxysilane Examples of the dispersion medium include alcohols such as methanol, ethanol, and isopropanol, and acetone.

A mixture of water and an organic solvent such as ketones such as methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, and ethers such as dioxane, tetrahydrofuran, methyl cellosolve, and ethyl cellosolve is used. The mixing ratio of the organic solvent and water is preferably 0.01 to 1 part by weight, more preferably 0.05 to 0.5 part by weight, per 1 part by weight of the organic solvent.

The silane coupling agent used in the present invention has the property of forming a film by reacting with hydroxyl groups, and the silane coupling agent has the property of forming a film by reacting with hydroxyl groups. If it is, it is presumed that it will react and form a film on the two surfaces.

By causing the organic titanate compound to act on the surface of the solid fine particles, the organic titanate compound reacts with moisture in the air and is hydrolyzed.

Mainly forms a titanium oxide layer. This titanium oxide layer also contains an alkyl group derived from an organic titanate compound, and it is presumed that the alkyl group also acts to make the surface of the liquid crystal spacer hydrophobic.

The surface of the liquid crystal spacer, which has become hydrophobic in this way, significantly reduces the adsorption of moisture in the air and becomes dry. It is considered that the dispersibility is very good when dispersing on the substrate. Furthermore, since the wettability of the organic titanate compound to the surface of the solid fine particles is poor, the adhesion of the titanium oxide layer to the solid fine particles tends to be poor.

Therefore, it is necessary to use a large amount of organic titanate compound, but if the surface of the solid fine particles is previously treated with a silane coupling agent to form a film, the film has extremely good affinity with the organic titanate compound. All of the above-mentioned drawbacks can be eliminated and a robust titanium oxide layer can be efficiently formed over a wide area on the surface of a liquid crystal spacer.

(Margin below) (Example) The present invention will be specifically described below based on two examples.

JiJLL Plastic fine particles with a particle size of 10μ (Micropearl 5P-210 manufactured by Block Fine Electric Cal ■) Log, tetrabutoxy titanium (B-1 manufactured by Nippon Soda ■) 0.0
Add a solution of 8g dissolved in 15-n-hexane,
After mixing well, n-hexane was evaporated. Then,
This material was thoroughly ground in a mortar.

The treated fine particles thus obtained were dispersed on a glass substrate by the following method, and the dispersibility was evaluated.

For the evaluation, a dispersion device shown in FIG. 1 was used. In addition.

In the figure, 1 is an air supply pipe, 2 is a nozzle, 3 is a spacer container,
4 is a glass substrate, and compressed air is discharged from the lower end of the nozzle 2 toward the spacer container 3. The pressure of compressed air is 3 kg/d, and the temperature inside the device is 50
The °C1 discharge time is set to 30 seconds. Also,
A square glass substrate with one side of 15C1 was used.

Collect 0.1 g of treated fine particles into a 1OOIIdl beaker.

Air was forced out from the nozzle to disperse the fine particles on the glass substrate. Select nine observation areas of the same area on the glass substrate,
At t7, count the number of aggregated particles in each observation area where three or more particles are aggregated, and calculate the total number in the 9 observation areas. It was recorded as a result. The results are shown in Table 1.

The plastic fine particles Log used in Example 1 were dispersed in a mixture of too much water and 900 g of ethanol, and 0.1 gt of gamma-aminopropyltrimethoxysilane (A-110 manufactured by Nippon Unicar Co., Ltd.) was added to this. The mixture was added and stirred at room temperature for 3 hours.Then, the reaction solution was filtered and the resulting fine particles were heat-treated at 200°C for 5 hours.

To the treated fine particles thus obtained, 0.08 g of tetrabutoxy titanium (B-1 manufactured by Nippon Soda) was added for 15 days.
After adding a solution of 100% in n-hexane and mixing well, the n-hexane was evaporated. Next, this material was sufficiently ground in a mortar.

About the treated fine particles obtained in this way.

When the dispersibility was evaluated in exactly the same manner as in Example 1, the results shown in Table 1 were obtained.

For comparison purposes, a dispersion test was carried out in exactly the same manner as in Example 1 without titanating the plastic particles used in Example 1, and the results shown in Table 1 were obtained.

1. Polystyrene particles with a main particle size of 3 μm (5P-3 manufactured by Soken Chemical Co., Ltd.)
0') 0.15g of tetrabutoxytitanium (A-1 manufactured by Nippon Soda ■) per 10g for 15ad! After adding a solution dissolved in fi''% xane and mixing well, n-hexane was evaporated.Then, this was thoroughly ground in a mortar.

About the treated fine particles obtained in this way.

The dispersibility was evaluated in exactly the same manner as in Example 1, and the results shown in Table 1 were obtained.

10 g of polystyrene particles used in Example 3,
Dispersed in a mixture of 30 g of water and 70 g of isopropanol, and added gamma-5-nopropyltrimethoxysilane (
1 g'lr of Nippon Unicar A-187) was added and stirred at room temperature for 1 hour. Next, the reaction solution was filtered and the obtained fine particles were heat-treated at 75°C for 2 hours.

To the treated fine particles thus obtained, 0.15 g of tetrabutoxy titanium (A-1 manufactured by Nippon Soda) was added for 15 days.
After adding a solution of 100% in n-hexane and mixing well, the n-hexane was evaporated. Next, this material was thoroughly ground in a mortar.

About the treated fine particles obtained in this way.

When the dispersibility was evaluated in exactly the same manner as in Example 1, the results shown in Table 1 were obtained.

Five comparisons 1 A dispersion test was conducted in exactly the same manner as in Example 1 without titanating the plastic particles used in Example 3, and the results shown in Table 1 were obtained.

Silica particles with a particle size of 1 μm (Seahoster Kt!-Ploo manufactured by Nippon Shokubai Chemical Co., Ltd.) Tetrakis (2-ethylhexoxy) titanium (To manufactured by Nippon Soda ■) for Log
A solution of 0.3 g of T) dissolved in 15d of n-hexane was added and mixed well, and then the n-hexane was evaporated. Next, this material was sufficiently ground in a mortar.

The dispersibility of the treated fine particles thus obtained was evaluated in exactly the same manner as in Example 1, and the results shown in Table 2 were obtained.

Back twisting 10 g of silica particles used in Example 5 were mixed with 200 g of water.
g and 800 g of acetone, 3 g of gamma-methacryloxypropyltrimethoxysilane was added thereto, and the mixture was stirred at room temperature for 30 minutes. Thereafter, one reaction solution was filtered and the obtained fine particles were heat-treated at 300'C for 1 hour.

Tetrakis 2 was added to the treated fine particles thus obtained.
-ethylhexoxy) titanium (TOT manufactured by Nippon Soda)
A solution of 0.3 g dissolved in 15d of n-hexane was added, mixed well, and the n-hexane was evaporated.
Next, this material was thoroughly ground in a mortar.

About the treated fine particles obtained in this way.

When the dispersibility was evaluated in exactly the same manner as in Example 1, the results shown in Table 2 were obtained.

A dispersion test was conducted on the silica particles used in Comparative Example 5 in exactly the same manner as in Example 1 without titanate treatment, and the results shown in Table 2 were obtained.

1 application 1 Plastic fine particles with a particle size of 8μ (Microvar 5P-208 manufactured by Building Block Fine Kagocal) Log were dispersed in a mixed solution of 450 g of ethanol, and N was added to the mixture.

N-bis[3-()rimethoxysilyl)propyl]ethylenediamine (rst, 8214 manufactured by Toshiba Silicone ■)
) was added thereto, and the mixture was stirred at room temperature for 30 minutes. Next, the reaction solution was filtered, and the resulting fine particles were heat-treated at 100° C. for 2 hours.

To the treated fine particles thus obtained, 0.1 g of tetrabutoxy titanium (Nippon Soda B-1) was added to 15M
A solution of 1 dissolved in n-hexane was added and mixed well, and then the n-hexane was evaporated. Next, this material was sufficiently ground in a mortar.

The titanium content of the treated fine particles thus obtained was determined. Quantification was performed using an ICP emission spectrometer after decomposing the sample with sulfuric acid and nitric acid. As a result, the titanium content per surface area of the treated fine particles was close to the theoretical value of 2.
It was 2■.

The dispersibility of the treated fine particles was evaluated in exactly the same manner as in Example 1, and the results shown in Table 2 were obtained.

Practical Benefit Team 1 In Example 7, the titanium content per surface area of treated fine particles obtained in exactly the same manner as in Example 7 except that the plastic fine particles were not treated with a silane coupling agent was 1/12 of the theoretical value. It was 0.19■.

The dispersibility of the treated fine particles was evaluated in exactly the same manner as in Example 1, and the results shown in Table 2 were obtained.

(Effects of the Invention) The liquid crystal spacer thus obtained has extremely excellent dispersibility and thus has the following effects.

■ Significantly improves the gap accuracy of liquid crystal cells.

Ideally, liquid crystal spacers that control the gap between glass substrates should be dispersed as a single particle, but in practice it is acceptable even if two or three particles are aggregated and dispersed. This is the common sense of those skilled in the art. Spacers according to the prior art produced many clusters of a few to 10 particles, which caused problems in controlling the gap.
The spacer according to the invention is significantly improved in this respect.

■Deterioration in contrast of liquid crystal display is significantly reduced.

In the case of a transmissive liquid crystal cell, if a large number of spacers are aggregated, that part will usually appear white, and if there are many white parts in black and white display, regardless of the display function,
Naturally, the black and white display contrast is significantly reduced. This is not the case with the spacer of the present invention.

■There is no appearance of minute spots due to agglomeration of spacers on the liquid crystal display screen.

These effects make it possible to obtain a liquid crystal spacer with ideal performance such as good gap accuracy and high display quality.

Furthermore, a liquid crystal spacer having the above-mentioned advantages can be obtained simply by treating solid fine particles with an organic titanate compound, and is extremely easy to manufacture and has excellent productivity.

In particular, if solid fine particles are treated with a silane coupling agent in advance to form a film on their surface, the organic titanate compound that is well bonded to the fine particles via this film will be formed over a wide area.

A liquid crystal spacer with extremely excellent dispersibility can be obtained.

Figure 1 is a schematic diagram showing a dispersion test device for liquid crystal spacers.

DESCRIPTION OF SYMBOLS 1... Air supply pipe, 2... Nozzle, 3... Spacer volume 4... Glass substrate.

Claims (1)

[Claims] 1. A spacer for a liquid crystal, characterized in that a titanium oxide layer is provided on the surface of solid fine particles. 2. A spacer for a liquid crystal, characterized in that a film obtained by treating the surface of solid particles with a silane coupling agent is provided, and a titanium oxide layer exposed on the surface of the film is provided. 3. A method for manufacturing a liquid crystal spacer, which comprises treating solid particles with a silane coupling agent to form a film, and then treating the solid particles with the film formed thereon with an organic titanate compound.