JP2533648B2 - Liquid crystal spacer and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD 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 having extremely excellent dispersibility and a method for manufacturing the same.

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

However, in general, the spacers for fine liquid crystals of this type are likely to be aggregated with each other, and several to ten spacers for liquid crystals are likely to be aggregated into a lump. When the spacers for liquid crystals are arranged between the glass substrates in such a state, the gap accuracy is reduced, and particularly in the transmissive liquid crystal cell for monochrome display,
Since the aggregated portion usually looks white, the black-and-white display contrast is reduced.

Conventionally, in order to improve the dispersibility of spacers for liquid crystals, for example, JP-A-62-195623 discloses a method of improving the dispersibility by irradiating ultrasonic waves. However, this method is industrially extremely unpractical in that it requires a special device and uses ultrasonic waves. It is obvious that it is most direct and effective to prevent mutual aggregation by processing the liquid crystal spacers themselves, and it is industrially advantageous, but in the prior art, concrete means for this have been proposed. It has not been.

(Problems to be Solved by the Invention) The present invention has been made by paying attention to the above circumstances.
By improving the dispersibility of the spacer for liquid crystal, the gap accuracy of the liquid crystal cell can be remarkably improved, the decrease in the contrast of the liquid crystal display can be remarkably reduced, and minute spots due to the aggregation of the spacers on the liquid crystal display screen can be obtained. It is an object of the present invention to provide a liquid crystal spacer that never appears and a manufacturing method thereof.

(Means for Solving the Problem) The liquid crystal spacer of the present invention is characterized in that the titanium oxide layer derived from the organic titanate compound is provided on the surface of the solid fine particles, thereby achieving the above object. To be done. In another spacer for liquid crystal of the present invention, a coating obtained by treating a solid fine particle with a silane coupling agent is provided, and a titanium oxide layer derived from an organic titanate compound is provided on the surface of the coating. The above-mentioned object is achieved by that.

The method for producing a spacer for a liquid crystal of the present invention is characterized in that solid fine particles are treated with a silane coupling agent to form a film, and then the solid fine particles having the film formed thereon are treated with an organic titanate compound. The above object is achieved by the above.

Examples of the material and shape of the solid fine particles used in the present invention include the following.

[Material]

Linear or crosslinked polymers such as polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polytetrafluoroethylene, polystyrene, polymethylmethacrylate, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyimide, polysulfone, polyphenylene oxide, polyacetal, etc .;
Epoxy resin, phenol resin, melamine resin, unsaturated polyester resin, divinylbenzene polymer, divinylbenzene-styrene copolymer, divinylbenzene-acrylic acid ester copolymer, diallylphthalate polymer,
Resins having a network structure such as triallyl isocyanurate polymer and benzoguanamine polymer. Of the above solid fine particles, particularly preferable are resins having a network structure such as a dizenylbenzene copolymer, a divinylbenzene-styrene copolymer, a divinylbenzene-acrylic acid ester copolymer and a diallylphthalate polymer.

As the inorganic material, silicate glass, borosilicate glass, lead glass, soda lime glass, alumina, alumina silicate or the like can be used. Of these, silicate glass and borosilicate glass are particularly preferable.

〔shape〕

The shape of the solid fine particles is not limited, but, for example, a solid spherical shape, an elliptic spherical shape, or a cylindrical shape having the following dimensions can be used.

For solid spherical solid particles, the diameter is 0.1 μm to 1000 μ
m is preferable, and a particularly preferable range is 1 μm to
It is 100 μm.

In the case of ellipsoidal solid particles, the minor axis is 0.1 μm to 1000
The range is preferably μm, and the particularly preferred range is 1 μm.
~ 100 μm. The ratio of the major axis to the minor axis is preferably in the range of 1-10, particularly preferably 1-5.

In the case of cylindrical solid particles, the diameter is 0.5μm to 1000μ
m is preferable, and a particularly preferable range is 3 μm to
It is 100 μm. The length-to-diameter ratio of the cylinders should be in the range 1-50, with a particularly preferred range being 1-10.

The operation of treating these solid fine particles with an organic titanate compound is, for example, the following method.

Solid fine particles are immersed in a treatment liquid containing an organic titanate compound, the treatment liquid is filtered off, and then dried.

The treatment liquid containing the organic titanate compound is sprayed or applied to the solid fine particles, and then dried.

The solvent of the treatment liquid is, for example, n-hexane, dichlorohexane, benzene, toluene, trichlene, Freon-13.
3 etc.

In the method (1), a method of dissolving the organic titanate compound in a solvent, immersing the solid fine particles in the solvent, and evaporating the solvent while sufficiently mixing is preferable. After evaporating the solvent, it is preferable to heat at 60 ℃ to 100 ℃,
This heating step may be omitted.

In the above method, it is also possible to apply the treatment liquid to a product obtained by thinly spreading solid fine particles on a glass plate, a metal plate or the like using a spray gun or the like. After coating, heat treatment may be performed under the above heating conditions.

The organic titanate compound used in the present invention includes:
For example, tetraethoxy titanium Ti (OC ₂ H ₅ ) ₄ , tetrapropoxy titanium Ti (OC ₃ H ₇ ) ₄ , tetrabutoxy titanium Ti (OC
₄ H ₉ ) ₄ , Tetrapenttotitanium Ti (OC ₅ H ₁₁ ) ₄ , Tetrahexoxy Titanium Ti (OC ₆ H ₁₃ ) ₄ , Tetrakis (2-ethylhexoxy) Titanium Ti [OCH ₂ CH (C ₂ H ₅ ) C ₄ H _{9] 4,} tetradodecyl alkoxy titanium Ti (OC ₁₂ H _{25) 4,} tetra stearoxy titanium Ti (OC ₁₇ H _{35) 4,} dipropoxy-bis (acetylacetonato) titanium Ti (OC ₃ H _{7) 2} 〔OC ・ (CH ₃ ) CHCOC
H ₃ ] ₂ , dibutoxy bis (triethanolaminato)
Titanium Ti (OC ₄ H ₉ ) ₂ [OC ₂ H ₄ N (C ₂ H ₄ OH) ₂ ] ₂ , dividroxy bis (lactato) titanium Ti (OH) ₂ [OCH (CH ₃ ) COOH] ₂ ,
Titanium propokisiooctylene glycolate Ti
[OCH ₂ CH (C ₂ H ₅ ) CH (C ₃ H ₇ ) OH] _{4 and the} like are used, and among them, particularly preferred are tetraproxy titanium, tetrabutoxy titanium, tetrakis (2-ethylhexoxy) titanium, Dipropoxy bis (acetylacenato)
Titanium, dibutoxy bis (triethanolaminato)
Titanium.

The organic titanate compound treated on the surface of the solid fine particles by the above steps reacts with moisture in the air in an exposed state and is hydrolyzed to form, for example, a titanium oxide layer having the following structure. It seems to be.

The amount of the titanium oxide layer formed in a thin film on the surface of the solid fine particles is the titanium-equivalent weight, and the surface area of the solid fine particles is 1 m.
^It is preferable to set it in the range of 0.01 mg to 500 mg per ² .
A more preferable amount of titanium oxide layer is 0.1 mg to 100 mg. If the amount of titanium oxide is less than 0.01 mg per 1 m ² of surface area of the solid fine particles in terms of titanium, the effect of preventing aggregation of the liquid crystal spacer is small. Conversely, the amount of titanium oxide layer is the titanium equivalent weight, the surface area of the solid fine particles
If it is more than 500 mg per 1 m ^{2, it} may cause unfavorable results such as a decrease in electric resistance.

Further, in the present invention, in order to improve the adhesiveness between the solid fine particles and the titanium oxide layer, the solid fine particles are previously treated with a silane coupling agent to form a film, and the solid fine particles having the film formed thereon are You may treat with an organic titanate compound like this.

The operation of treating the solid fine particles with the silane coupling agent is as follows.

The solid fine particles are immersed in a treatment liquid containing a silane coupling agent, the treatment liquid is filtered, and then the solid fine particles are dried.

The treatment liquid containing the silane coupling agent is sprayed or applied to the solid fine particles and then dried.

In the above method, conditions such as the concentration of the treatment liquid, the treatment temperature, the treatment time and the like are as follows, for example. 1 part by weight of solid fine particles is dispersed in 1 to 1000 parts by weight, preferably 5 to 500 parts by weight of a suitable dispersion medium (described later), and 0.001 to 1 part by weight, preferably 0.005 to 0.3 part by weight of a silane coupling agent is added thereto. In addition, 10 minutes to 12 hours at room temperature, preferably 30 minutes to 6
After stirring for an hour, the dispersion medium is separated and the remaining solid fine particles are
40 ℃ ~ 500 ℃, preferably 60 ℃ ~ 400 ℃ 15 minutes ~ 12 hours,
It is preferably heated for 30 minutes to 5 hours.

In the above method, it is also possible to apply the treatment liquid to a product obtained by thinly spreading solid fine particles on a glass plate, a metal plate or the like using a spray gun or the like. After coating, heat treatment may be performed under the above heating conditions.

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

Vinyl-based vinyltriethoxysilane, vinyl-tris (2-methoxyethoxy) silane Methacrylic-based gamma-methacryloxypropyltrimethoxysilane Amino-based gamma-aminopropyltrimethoxysilane, N-beta- (amino) ethyl-gamma-aminopropyl -Trimethoxysilane, 3- [N-allyl-N (2-aminoethyl)] aminopropyltrimethoxysilane, 3- (N-allyl-N-methacryl) aminopropyltrimethoxysilane, 3- (N, N- Diglycidyl) aminopropyltrimethoxysilane amine N, N-bis [(methyldimethoxysilyl) propyl] amine, N, N-bis [3- (trimethylsilyl) propyl]
Amine, N, N-bis [3- (methyldimethoxysilyl) propyl] ethylenediamine amide N, N-bis [(methyldimethoxysilyl) propyl] methacrylamide, N, N-bis [3- (trimethoxysilyl) propyl ] Methacrylamide Amidoglycidyl Gamma-Glycidoxypropyltrimethoxysilane, N-
Glycidyl-N, N-bis [3- (trimethoxysilyl)
Propyl] amine mercapto type gamma-mercaptopropyltrimethoxysilane Dispersion media include alcohols such as methanol, ethanol and isopropanol, ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, dioxane, tetrahydrofuran and methyl. A mixture of water and an organic solvent such as ethers such as cellosolve and ethyl cellosolve is used. The mixing ratio of the organic solvent and water is preferably 0.01 to 1 part by weight of water, more preferably 0.05 to 1 part by weight of the organic solvent.
0.5 parts by weight.

The silane coupling agent used in the present invention has a property of reacting with a hydroxyl group to form a film, and a hydroxyl group of a trace amount of water molecules bonded to the surface of solid fine particles, or a solid fine particle has other hydroxyl groups. If it is present, it is presumed that it reacts with it to form a film on the surface.

When the organic titanate compound is allowed to act on the surface of the solid fine particles, the organic titanate compound reacts with moisture in the air and is hydrolyzed to mainly form a titanium oxide layer. The titanium oxide layer also contains an alkyl group derived from the organic titanate compound, and it is presumed that the action of the alkyl group also acts to make the liquid crystal spacer surface hydrophobic. In this way, the surface of the liquid crystal spacer, which has become hydrophobic, has a significantly reduced adsorption of moisture in the air and is in a dry state. As a result, it is extremely difficult for the spacers to coagulate. It is considered that the dispersibility becomes extremely good when dispersed on the substrate. In addition, the wettability of the organic titanate compound to the surface of the solid fine particles is poor, so that 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 the organic titanate compound. If a film is formed in advance by treating with a silane coupling agent, the film has a very good affinity with the organic titanate compound.
It is possible to eliminate all of the above drawbacks and efficiently form a robust titanium oxide layer on the surface of the liquid crystal spacer over a large area.

(Examples) Hereinafter, the present invention will be specifically described based on Examples.

Example 1 10 g of plastic fine particles having a particle size of 10 μm (Micropearl SP-210 manufactured by Sekisui Fine Chemical Co., Ltd.) and 15 ml of 0.08 g of tetrabutoxy titanium (B-1 manufactured by Nippon Soda Co., Ltd.)
The solution of n-hexane was added and mixed well, and then n-hexane was evaporated. Then, this 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. Evaluation is first
The dispersing device shown in the figure was used. In the figure, 1 is an air inlet pipe, 2 is a nozzle, 3 is a spacer container, 4 is a glass substrate,
Pressurized air is discharged from the lower end of the nozzle 2 toward the spacer container 3. The pressure of the compressed air is 3k
g / cm ² , the temperature inside the device is set to 50 ° C, and the discharge time is set to 30 seconds. The glass substrate used was a square with a side of 15 cm.

0.1 g of treated fine particles was collected in a 100 ml beaker, and air was forced out from a nozzle to disperse the fine particles on a glass substrate. Nine observation areas having the same area on the glass substrate were selected, and the number of aggregated fine particles was counted for the areas where three or more fine particles were aggregated in each observation area. The results are shown in Table 1.

Example 2 10 g of the plastic particles used in Example 1 were dispersed in a mixed solution of 100 g of water and 900 g of ethanol, and 0.1 g of gamma-aminopropyltrimethoxysilane (A-110 manufactured by Nippon Unicar Co., Ltd.) was added thereto. And stirred at room temperature for 3 hours. Then, the fine particles obtained by separating the reaction solution by filtration were heat-treated at 200 ° C. for 5 hours.

To the treated fine particles thus obtained, 0.08 g of tetrabutoxytitanium (B-1 manufactured by Nippon Soda Co., Ltd.) was added to 15 ml of n-
Add a solution dissolved in hexane and mix well, then n-
Hexane was evaporated. Then, this was thoroughly ground in a mortar.

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

Comparative Example 1 A dispersion test was conducted in exactly the same manner as in Example 1, except that the plastic fine particles used in Example 1 were not treated with titanate, and the results shown in Table 1 were obtained.

Example 3 Polystyrene particles having a particle size of 3 μm (SP-3 manufactured by Soken Kagaku)
0) 10g tetrabutoxy titanium (manufactured by Nippon Soda Co., Ltd.)
A-1) 0.15 g of a solution prepared by dissolving 15 ml of n-hexane was added and mixed well, and then n-hexane was evaporated. Then, this was thoroughly ground in a mortar.

The treated fine particles thus obtained were evaluated for dispersibility by the same method as in Example 1, and the results shown in Table 1 were obtained.

Example 4 10 g of polystyrene particles used in Example 3,
The mixture was dispersed in a mixed solution of 30 g of water and 70 g of isopropanol, 1 g of gamma-aminopropyltrimethoxysilane (A-187 manufactured by Nippon Unicar Co., Ltd.) was added thereto, and the mixture was stirred at room temperature for 1 hour. Then, the fine particles obtained by separating the reaction solution by filtration were heat-treated at 75 ° C. for 2 hours.

To the treated fine particles thus obtained, 0.15 g of tetrabutoxytitanium (A-1 manufactured by Nippon Soda Co., Ltd.) was added to 15 ml of n-
Add a solution dissolved in hexane and mix well, then n-
Hexane was evaporated. Then, this was thoroughly ground in a mortar.

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

Comparative Example 2 A dispersion test was conducted in exactly the same manner as in Example 1, except that the plastic fine particles used in Example 3 were not treated with titanate, and the results shown in Table 1 were obtained.

Example 5 Silica particles having a particle size of 1 μm (Nippon Shokubai Kagaku Kogyo Co., Ltd.)
Seacaster KE-P100) 10 g, tetrakis (2-ethylhexoxy) titanium (Nippon Soda Co., Ltd. TOT) 0.3 g
Was dissolved in 15 ml of n-hexane, mixed well, and then n-hexane was evaporated. Then, this was thoroughly ground in a mortar.

The treated fine particles thus obtained were evaluated for dispersibility by the same method as in Example 1, and the results shown in Table 2 were obtained.

Example 6 10 g of the silica particles used in Example 5 were dispersed in a mixed solution of 200 g of water 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, the fine particles obtained by filtering the reaction solution were heat-treated at 300 ° C. for 1 hour.

Tetrakis 2-ethylhexoxy) titanium (TO, manufactured by Nippon Soda Co., Ltd.) was added to the treated fine particles thus obtained.
A solution prepared by dissolving 0.3 g of T) in 15 ml of n-hexane was added and mixed well, and then n-hexane was evaporated. Then, this was thoroughly ground in a mortar.

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

Comparative Example 3 The silica particles used in Example 5 were subjected to a dispersion test in exactly the same manner as in Example 1 without the titanate treatment, and the results shown in Table 2 were obtained.

Example 7 10 g of plastic fine particles having a particle size of 8 μm (Micropearl SP-208 manufactured by Sekisui Fine Chemical Co., Ltd.)
The mixture was dispersed in 50 g of a mixed solution, 1 g of N, N-bis [3- (trimethoxysilyl) propyl] ethylenediamine (TSL8214 manufactured by Toshiba Silicone Co., Ltd.) was added thereto, and the mixture was stirred at room temperature for 30 minutes. Then, the reaction solution was filtered to obtain 100
It heat-processed at 2 degreeC for 2 hours.

To the treated fine particles thus obtained, 0.1 g of tetrabutoxytitanium (B-1 manufactured by Nippon Soda Co., Ltd.) was added to 15 ml of n-
Add a solution dissolved in hexane and mix well, then n-
Hexane was evaporated. Then, this was thoroughly ground in a mortar.

The titanium content of the treated fine particles thus obtained was quantified. The quantification was performed using an ICP emission spectrophotometer after decomposing the sample with sulfuric acid and nitric acid. As a result, the titanium content per 1 m ² of surface area of the treated fine particles was 2.2 mg, which was close to the theoretical value.

The treated fine particles were evaluated for dispersibility by the same method as in Example 1, and the results shown in Table 2 were obtained.

Example 8 The titanium content per 1 m ² of 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 the silane coupling agent was 1/12 of the theoretical value. Was 0.19 mg.

The treated fine particles were evaluated for dispersibility by the same method as in Example 1, and the results shown in Table 2 were obtained.

(Effect of the Invention) Since the spacer for liquid crystal thus obtained has extremely excellent dispersibility, it has the following effects.

The gap accuracy of the liquid crystal cell is significantly improved.

Ideally, the liquid crystal spacer that controls the gap of the glass substrate should be dispersed with a single particle, but in practice it is acceptable even if a few particles are aggregated and dispersed. Is the common sense of those skilled in the art. The conventional spacer has a problem in controlling the gap, because a large number of aggregates of several to 10 particles are generated.
The spacer according to the present invention is remarkably improved in this respect.

The decrease in the contrast of the 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 usually looks white, and if there are many white parts in the black and white display regardless of the display function, the display contrast of black and white is obviously remarkable. descend. This is not the case with the spacer of the present invention.

No fine spots appear due to the aggregation of spacers on the liquid crystal display screen.

Due to these effects, it is possible to obtain a liquid crystal spacer having an ideal performance with good gap accuracy and high display quality. Moreover, the spacer for liquid crystal having the above advantages can be obtained only by treating the solid fine particles with the organic titanate compound, and the production is extremely simple and the productivity is excellent.

In particular, when solid fine particles are previously treated with a silane coupling agent to form a film on the surface, an organic titanate compound that is well bonded to the fine particles is formed over a large area through this film. It is possible to obtain a spacer for liquid crystal which is extremely excellent in dispersibility.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a dispersibility test device for a liquid crystal spacer. 1 ... Air inlet pipe, 2 ... Nozzle, 3 ... Spacer container, 4 ...
… Glass substrate.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-73225 (JP, A) JP-A-62-262737 (JP, A) JP-A-64-77024 (JP, A) JP-A-62- 169122 (JP, A) JP 62-157322 (JP, A) JP 61-283624 (JP, A) JP 62-177070 (JP, A)

Claims (3)

(57) [Claims] 1. A liquid crystal spacer comprising a titanium oxide layer derived from an organic titanate compound exposed on the surface of solid fine particles. 2. A coating obtained by treating a silane coupling agent on the surface of solid fine particles, and a titanium oxide layer derived from an organic titanate compound exposed on the surface of the coating. Liquid crystal spacer. 3. A method for producing a spacer for a liquid crystal, which comprises treating the solid fine particles with a silane coupling agent to form a coating film, and then treating the solid fine particles having the coating film with an organic titanate compound.