JPH0436724A - Coated fine particle and production thereof - Google Patents

Abstract

PURPOSE:To adhere colored fine particles to a substrate by providing a titanium oxide layer on the surface of the colored fine particles, coating the layer with an epoxy resin and melting the resin layer by heating. CONSTITUTION:After the epoxy resin is dissolved in a solvent, such as acetone, the colored fine particles and hardener are added into the soln. and are dispersed by mixing. While the soln. is stirred, the soln. is evaporated to coat the surfaces of the colored fine particles with the epoxy resin compsn. The titanium oxide layer may be provided between the colored fine particles and the epoxy resin layer in order to enhance the adhesiveness of the colored fine particles an the epoxy resin layer and to uniformly provided the thin epoxy resin layer and to uniformly provide the thin epoxy resin layer on the surface of the colored fine particles.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to coated fine particles having colored fine particles as a core material and a method for producing the same, and more specifically, to gap materials for liquid crystal display cells,
Gap material for electrochromic display cells, conductive or insulating spacers for electrode plates, or spacers for maintaining gaps between films, sheets, and blocks for uses other than those listed above, flat or concave surfaces for optical and other uses. The present invention relates to coated fine particles used for forming fine protrusions thereon and a method for producing the same.

(Prior art) Colored fine particles are used as liquid crystal spacers used in liquid crystal display cells, as labeling materials such as fluorescent particles used in flow cytometry in the biochemical field, and as standards used in particle size measurements using electron microscopes. Particles have applications as diagnostic carriers used in immunological diagnostic reagents.

A case where colored fine particles are used as a spacer for a liquid crystal display cell will be explained. In a liquid crystal display cell, it is necessary to maintain a constant gap between two translucent glass substrates or plastic substrates, so colored particles of approximately constant diameter are placed between the two substrates at a predetermined interval as spacers. Ru. For example, see JP-A-57-189117, JP-A-59-24829, and JP-A-1-144021.

(Problems to be Solved by the Invention) However, in conventional liquid crystal display cells, the colored fine particles are not fixed to the substrate, and therefore the following drawbacks have occurred.

(2) In the process of assembling a liquid crystal display cell, spacers placed on the substrate scatter and disappear when air is blown onto the substrate or air is sucked from the substrate.

(2) In the process of injecting liquid crystal into a liquid crystal display cell, the spacers move on the substrate, causing uneven placement of the spacers on the substrate.

■When the liquid crystal display cell is driven, the spacer moves due to electrical and hydrodynamic forces.

In order to overcome these drawbacks, the spacer is required to be fixed to the substrate. However, a specific method for fixing colored fine particles to a substrate has not been established so far.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to have a desired adhesion to the substrate so that it can be fixed to the substrate when used, for example, as a spacer for a liquid crystal display cell. An object of the present invention is to provide coated fine particles. Another object of the present invention is to provide coated fine particles in which the adhesive resin layer provided on the surface of the fine particles does not peel off from the fine particles or cohere with each other.

(Means for Solving the Problems) The coated fine particles of the present invention have colored fine particles and an epoxy resin layer provided on the surface of the colored fine particles, thereby achieving the above object.

The method for producing coated fine particles of the present invention includes a step of treating colored fine particles with an epoxy resin composition, thereby achieving the above object. Preferably, a titanium oxide layer is provided between the colored fine particles and the epoxy resin layer.

The colored fine particles used in the present invention refer to colored solid fine particles. The solid fine particles may be formed from an organic substance or an inorganic substance.

Examples of the organic solid particles include the following materials. polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polytetrafluoroethylene,
Thermoplastic resins such as polystyrene, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyimide, polysulfone, polyphenylene oxide, polyacetal; epoxy resins, phenolic resins, melamine resins, unsaturated polyester resins, divinylbenzene polymers, Thermosetting resins such as divinylbenzene-styrene copolymers, divinylbenzene-acrylic acid ester copolymers, diacryl phthalate polymers, triallyl isocyanurate polymers, and benzoguanamine polymers.

Among the solid fine particles made of the above-mentioned organic substances, particularly preferred are melamine resin, divinylbenzene copolymer,
These are thermosetting resins such as divinylbenzene-styrene copolymer, divinylbenzene-acrylic acid ester copolymer, and diacryl phthalate polymer.

Examples of the inorganic solid particles include the following materials. Silicate glass, borosilicate glass, lead glass, soda lime glass, alumina, alumina silicate, etc.

Among these, silicate glass and borosilicate glass are particularly preferred.

Although the shape of the solid fine particles is not limited, for example, a perfect sphere, an elliptical sphere, or a columnar shape having the dimensions shown below are preferable. In the case of true spherical solid particles, the diameter of the solid particles is 0.1 μm.
The range of 1000 μm is good, and the particularly preferable range is 1 μm.
5=100 μm. In the case of elliptical spherical solid particles, the short axis is preferably in the range of 0.1 μm=1000 μm, and a particularly preferable range is 1 μm to 100 μm.

The ratio of the long axis to the short axis of the solid fine particles is preferably in the range of 1 to 10, with a particularly preferable range of 1 to 5. In the case of cylindrical solid particles, the diameter is 0.5 μm to 1000 μm.
The range is preferably within the range of m, and the particularly preferable range is 3μm=
It is 100 μm.

The length to diameter ratio of the cylinder may range from 1 to 50, with a particularly preferred range from 1 to 10.

Usually, the solid fine particles used are those used in liquid crystal spacers, labeling materials, standard particles, diagnostic carriers, and the like.

Colored fine particles are obtained by coloring solid fine particles made of these materials. When the solid particles are made of organic matter, the solid particles are colored by treating the solid particles with carbon black, disperse dyes, acid dyes, basic dyes, metal oxides, etc. to obtain colored particles. .

When the solid particles are inorganic, colored particles can be obtained by forming an organic film on the surface of the solid particles and decomposing or carbonizing this at high temperature.

Furthermore, if the material forming the solid fine particles itself has a color, it may be used as is without special coloring.

The epoxy resin layer provided on the surface of the colored fine particles is formed by treating the surface of the colored fine particles with an epoxy resin composition. The epoxy resin layer melts and becomes adhesive when heated to a predetermined high temperature. The thickness of the epoxy resin layer is preferably in the range of 0.01μ5n-100μ.

Next, the epoxy resin composition used in the present invention and the method of providing an epoxy resin layer on the surface of colored fine particles using the epoxy resin composition will be explained.

Epoxy resin compositions usually consist of an epoxy resin and a curing agent. The epoxy resin used in the present invention includes:
Bisphenol A type epoxy resin (represented by formula 1) obtained by reacting bisphenol A and epichlorohydrin, bisphenol F type epoxy resin obtained by reacting bisphenol F and epichlorohydrin (■
(represented by the formula), bisphenol AD type epoxy resin obtained by the reaction of bisphenol AD and epichlorohydrin (represented by the m formula), obtained by the reaction of the bisphenol compound represented by the formulas from ■ to ■ with epichlorohydrin Examples include epoxy resins, phenol novolac type epoxy resin (represented by the formula 4), and cresol borac type epoxy resin (represented by the formula ■).

(Hereinafter, blank spaces) In the epoxy resins represented by formulas (I) to (IX) above, n is usually 0 to 50, preferably 1 to 6. If n is 7 or more, the viscosity of the resin during heating and melting will be extremely high. When the resulting coated fine particles are placed on, for example, a glass plate and heated, the adhesive resin layer is difficult to melt and flow down, making it difficult to obtain desired adhesion to the glass plate. Also, when n is 0, the resin is liquid at room temperature,
Because the resin viscosity during heating is too low, the adhesive resin layer of the coated fine particles becomes sticky or spreads too much on the glass plate.

The epoxy resins represented by formulas (1) to (4) above may be used alone or in combination.

Particularly preferred among the epoxy resins represented by formulas ■ to ■ above are bisphenol A type epoxy resin (formula I), phenol novolac type epoxy resin (formula ■), and cresol novolac type epoxy resin (formula ■). .

As the curing agent used in combination with the above-mentioned epoxy resin in the present invention, those shown below are preferably used.

■Amine curing agent: Aliphatic amine compounds such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, menthendiamine, influorondiamine, bis(4-amino-3-methylmicrohexyl)methane; phenylenediamine, methylenedianiline, benzyldimethylamine, 2-
Aromatic amine compounds such as (dimethylaminomethylphenol).

■Polyaminoamide curing agent: ethylenediamine,
A condensation compound of polyethylene amine and organic carboxylic acid such as diethylene triamine, triethylene tetramine, tetraethylene pentamine, and pentaethylene tetramine. Here, as the organic carboxylic acid, used are polymerized fatty acid epoxidized unsaturated fatty acids obtained by heat treatment of unsaturated fatty acids such as linoleic acid and lilunic acid, anikenylsuccinic acid, amino acid compounds, and the like.

■Acid anhydride curing agents: dodecenyl succinic anhydride, polyadipic anhydride, phthalic anhydride, methylhexahydrophthalic anhydride, trimelli-nodic anhydride, pyromellitic anhydride, etc.

■Basic active hydrogen compound curing agent: dicyandiamide, adipic acid dihydrazide, eicosaniic acid dihydrazide, 7.11-octadecadiene-1,18-dicarbohydrazide, 1.3-bis(hydrazinocarboethyl)- 5-isopropylhydantoin, etc.

■Imidazole curing agent: 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-n-alkylimidazole, 2-phenylimidazole, 2-phenyl-2-methylimidazole, 2-ethylimidazole, cyanoethyl -2-methyl-imidazole,
l-cyanoethyl-2-ethyl-4-methylimidazole, 2,4-diamino-6-(2'-methylimidazolyl)ethyl-1; 3,5-triazine, 2,4-diamino-6-(2'- Ethyl-4-methylimidazolyl)ethyl-1,3,5-triazine, 2,4-diamino-6
-(2'-n-undecylimidazolyl)ethyl-1,
3,5-triazine, 2-phenylimidazole-4,
5-diyldimetatool, (5-methyl-2-phenyl-4-imidazolyl)methanol, etc.

■Tertiary amine curing agent: tris(dimethylaminomethyl)phenol, dimethylbenzylamine, 1.8-
diazabicyclo(5,4,0)undecane, etc.

■Others: monoethylamine salt of boron trifluoride,
Lewis acid salts such as piperidine salt of boron trifluoride, monoethylamine salt of trifluoromethanesulfonic acid, diphenyliodonium salt of hexafluorine hisoic acid, and Brønsted acid salts.

The above curing agents (1) to (4) are used directly in combination with an epoxy resin, or in the form of microcapsules. These curing agents cause a curing reaction when mixed with an epoxy resin and heated at a predetermined temperature. The temperature that causes curing varies depending on the type of curing agent and is usually between 50°C and 250°C. A particularly preferred curing temperature is 90°C to 200°C.

Hardening agent: 0.5 parts by weight per 100 parts by weight of epoxy resin
Although it can be used in a range of 100 parts by weight, a particularly preferable amount of curing agent added is 5 parts by weight per 100 parts by weight of epoxy resin.
Parts by weight to 50 parts by weight.

Among the above-mentioned curing agents, particularly preferred as curing agents that can be used in the present invention are the basic active hydrogen compound curing agent (1) and the imidazole curing agent (2). When these are mixed with epoxy resin, they do not cause a curing reaction at room temperature, so the resulting epoxy resin composition has a long dry life, can be stored for a long time, and can be stored at a specified temperature or higher. It can be rapidly cured by heating.

All of the above-mentioned curing agents are heat curing types. In the present invention, the following ultraviolet curing type curing agents can also be used.

(a) Aromatic diazonium salt (b) Aromatic sulfonium salt (C) Aromatic iodonium salt ASF-b+sbF-b These ultraviolet curing type curing agents are epoxy resin 10
It is preferable to use it in a range of 0.1 parts by weight to 10 parts by weight per 0 parts by weight.

The method for coating the colored fine particles with the epoxy resin composition is as follows.

After dissolving the epoxy resin in a solvent such as acetone, tetrahydrofuran, methyl ethyl ketone, benzene, or toluene, colored fine particles and a curing agent are added to the resulting solution and mixed and dispersed. Although the amount of solvent may be arbitrary, it is preferable that the concentration of the epoxy resin in the solution is in the range of 3% by weight to 30% by weight. Next, the epoxy resin composition is coated on the surface of the colored fine particles by evaporating the solvent by means such as reduced pressure while stirring the solution, thus forming an epoxy resin layer. Adding a small amount of a precipitant or surfactant that dissolves in the solvent but not in the epoxy resin into the solution prevents the coalescence and aggregation of particles that tend to occur as the solvent evaporates. can be prevented.

Water is particularly effective as such a precipitant.

In the present invention, in order to improve the adhesion between the colored fine particles and the epoxy resin layer, and to uniformly provide a relatively thin epoxy resin layer on the surface of the colored fine particles, titanium oxide is added between the colored fine particles and the epoxy resin layer. A material layer may also be provided.

The method for forming a titanium oxide layer on the surface of colored fine particles is as follows:
For example, this can be done by the following method.

After an organic titanate compound is dissolved in a solvent and the resulting solution is applied to the surface of the colored fine particles, the organic titanate compound is hydrolyzed to form a titanium oxide layer.

Examples of the organic titanate compound include tetraethoxoxytitanium Ti (OC2H5)J, tetrapropoxytitanium Ti (OCsHv)a, and tetrabutoxytitanium Ti (.

C4H9) 4% ftrahento beef city 97Ti (OC
sHt+) a, Tetra Hegyunteshititanium Ti (OC6H
13) i, Tetrakis (2-ethylhexoxy) titanium Ti [0CH2CH(C2Hs)C4H9] a, Tetradodecylalco-cow titanium Ti (QC12H26
) 4, Tetrastea oxytita 7Ti (OC+yH3s
) 4, dipropoxy bis(acetylacetonato)titaniumTi(OCsHy)2[0C(CH3)CHCOC
H3] 2, dibutoxy bis(triethanolaminato)titanium Ti(OC4H9)2 [0C2HJ(C2
H40H)+] 2. Dihydro beef ci bis(lactato)
f9 Ti(OH)2[0CR(C113)COO
Hco2, titanium bropoxyoctylene glycolate Ti [0CH2CH(C2ns)CH(C3Hv)
OHI a etc. are used. Particularly preferred are tetrapropoxy titanium, tetrabutoxy titanium, tetrakis (2-ethylhexoxy) titanium, dipropoxy bis (acetylacenato) titanium, and dibutoxy bis (triethanolaminato) titanium.

Examples of the above-mentioned solvents include n-hegyosan, cyclohegyosan, benzene, toluene, trichlene, freon-113, and the like. A suitable method for applying the organic titanate compound to the surface of the colored fine particles is to immerse the organic titanate compound in the solution and evaporate the solvent while thoroughly mixing. After evaporating the solvent,
It is preferable to heat at 60°C to 100°C as necessary.

It is presumed that the organic titanate compound formed on the surface of the colored fine particles by the above operation reacts with moisture in the air and is hydrolyzed to form a titanium oxide layer having the structure shown below.

The amount of the titanium oxide layer formed on the surface of the colored fine particles is preferably in the range of 0.01+ag to 500 mg per rrl of surface area of the colored fine particles, expressed as titanium equivalent weight. A more preferable amount of the titanium oxide layer is O, 1 mg to 100
mg. The amount of titanium oxide layer is titanium equivalent weight,
If it is less than O.Qlmg per 1 d of surface area of the solid fine particles, the adhesion between the epoxy resin layer and the colored fine particles will not be sufficient. On the other hand, the amount of the titanium oxide layer is 500+ag per 1 d of surface area of the colored fine particles in titanium equivalent weight.
If the amount is too large, unfavorable results such as a decrease in the electrical resistance of the coated fine particles will occur.

(Examples) The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples.

100 g of concentrated sulfuric acid was added to styrene plastic fine particles log having a fff diameter of 8.05 μm, and the mixture was stirred at 55° C. for 6 hours to perform acid treatment. On the other hand, 6 g of the basic dye Cachilon Black 5BH (manufactured by Hodokugaya Kagaku ■) was dissolved in 300 mJ2 of water, and acetic acid was added to prepare a dye bath whose pH was adjusted to 4. Add the above acid-treated plastic fine particles to this dye bath and dye at 95°C for 6 hours to obtain 10 g of black colored fine particles.
I got it.

Solid epoxy with an Evokin equivalent of 480 and a softening point of 68°C (manufactured by Yuka Shell Epoxy ■, trade name Ehicoat 1001)
) 2 g was added to L in 40ra of acetone and dissolved, and then 6 mft of water was added, and the colored fine particles Log,
and 2-ethyl-4-methylimidazole as a curing agent (manufactured by Shikoku Kasei Kogyo ■, trade name Curazol 2E4MZ)
After adding 0.4 g and thoroughly mixing, acetone was evaporated by stirring. The obtained dried product was crushed using a mortar to completely loosen the lumps.

The particle size of the coated fine particles obtained in this way was
When measured using a counter ZB/C-1000 type particle size measuring device, the average particle size was 8.45 μm.

From this result, the thickness of the epoxy resin layer was calculated to be 0.20 μm. Observation of the surface of the coated fine particles using a scanning electron microscope revealed that an epoxy resin layer was uniformly formed on the surface of the colored fine particles.

The coated fine particles were suspended in Freon 113 to obtain a spray liquid. The spray liquid was sprayed onto a glass plate from a nozzle. The coated fine particles did not aggregate with each other on the glass plate and showed good dispersibility. The glass plate having the coated fine particles was left in a heating furnace at 130° C. for 20 minutes. When the bonded area between the glass plate and the coated fine particles was observed using a scanning electron microscope at a magnification of 2000 times, it was found that a melted epoxy resin layer was present between the glass plate and the colored fine particles. Further, an operation of attaching an adhesive tape to the surface of the glass plate to which the coated fine particles were adhered (the surface on the side of the coated fine particles) and then peeling off the tape was repeated several times. Count the number of particles remaining on the glass plate before applying the adhesive tape to the glass plate surface and after applying the tape to the glass plate surface as described above, and then apply the tape to the glass plate surface. The ratio of the number of particles after the tape was attached to the surface of the glass plate (residual ratio) to the number of particles before was determined. As a result, the residual ratio was 0.95, and it was confirmed that the adhesion between the coated fine particles and the glass plate was sufficient.

Support! Silica particles with a master particle size of 1.15μ (Nippon Shokubai Chemical Co., Ltd.)
Seahoster WE-P100 (manufactured by Seishin Corporation) was dyed with a basic dye to obtain 10 g of blue colored fine particles.

As a hardening agent, dicyanamide (oiled shell epoxy)
0.2 g of DICY-7 (manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name) and 0.2 g of 2-phenylimidazole-4,5-diyldimetazole (manufactured by Shikoku Kasei Kogyo ■, trade name 2PHZ) were used.

Coated fine particles were obtained in the same manner as in Example 1 except that the above materials were used. The particle size of the coated fine particles was 1.35 μm. The thickness of the epoxy resin layer was calculated to be 0.10 μm. Observation of the surface of the coated fine particles using a scanning electron microscope revealed that an epoxy resin layer was uniformly formed on the surface of the colored fine particles.

Next, a spray solution was obtained in the same manner as in Example 1 except that the coated fine particles were used, and the spray solution was sprayed onto a glass plate. It was confirmed that the coated fine particles were well dispersed in the form of single particles on the glass plate. The glass plate having the coated fine particles was left in a heating furnace at 150'C for 30 minutes. As in Example 1, when the bonded portion between the glass plate and the coated fine particles was observed using an electron microscope, it was found that a melted epoxy resin layer was present between the glass plate and the colored fine particles. When the residual ratio of particles was determined in the same manner as in Example 1, the residual ratio was 0.95.

Melamine resin particles (manufactured by Unitika ■, Unipex WA) having a main particle diameter of 20.27 μm were dyed with an acid dye to obtain 10 g of red colored fine particles.

As a curing agent, l-cyanoethyl-2-ethyl-4-methylimidazole (manufactured by Shikoku Kasei Kogyo ■, trade name 2E4M) was used.
Z-CN) 0.4 g was used.

Coated fine particles were obtained in the same manner as in Example 1 except that the above materials were used. The particle size of this coated fine particle is 20.93 μm
Met. The thickness of the epoxy resin layer was calculated to be 0.33 μm. Observation of the surface of the coated fine particles using a scanning electron microscope revealed that an epoxy resin layer was uniformly formed on the surface of the colored fine particles.

Next, a spray solution was obtained in the same manner as in Example 1 except that the coated fine particles were used, and the spray solution was sprayed onto a glass plate. It was confirmed that the coated fine particles were well dispersed in the form of single particles on the glass plate. The glass plate having the coated fine particles was left in a heating furnace at 110°C for 30 minutes. As in Example 1, when the bonded portion between the glass plate and the coated fine particles was observed using an electron microscope, it was found that a melted epoxy resin layer was present between the glass plate and the colored fine particles. When the residual ratio of particles was determined in the same manner as in Example 1, the residual ratio was 1.0.

K Arashi Takumi etetrapropoxy titanium (manufactured by Nippon Sotatsu ■, product side A-1)
) 0.15g was dissolved in 15mA n-beef sun to prepare a solution, 10g of colored fine particles obtained in the same manner as in Example 1 was added to this solution, and after stirring well with a spatula, n- Hexane was evaporated.

Next, this material was sufficiently ground using a mortar to eliminate any lumps.

On the other hand, as an epoxy resin, solid epoxy with an epoxy equivalent of 480 and a softening point of 68°C (manufactured by Yuka Shell Epoxy ■,
Product name Epicote 1001) 2g in acetone 40r
After adding and dissolving in aA, add 6 mA of water to this solution,
10 g of the colored fine particles and a curing agent, 2-ethyl-
After adding 0.4 g of 4-methylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name: Curesol 2E4MZ) and thoroughly mixing, acetone was evaporated while stirring. The dried material was crushed using a mortar to completely loosen the lumps to obtain coated fine particles.

The particle size of the coated fine particles was 8.84 μm. The thickness of the epoxy resin layer was calculated to be 0.15 μm. Observation of the surface of the coated fine particles using a scanning electron microscope revealed that an epoxy resin layer was uniformly formed on the surface of the colored fine particles.

Next, a spray solution was obtained in the same manner as in Example 1 except that the coated fine particles were used, and the spray solution was sprayed onto a glass plate. It was confirmed that the coated fine particles were well dispersed in the form of single particles on the glass plate. The glass plate having the coated fine particles was left in a heating furnace at 130°C for 30 minutes. As in Example 1, when the bonded portion between the glass plate and the coated fine particles was observed using an electron microscope, it was found that a melted epoxy resin layer was present between the glass plate and the colored fine particles. When the residual ratio of particles was determined in the same manner as in Example 1, the residual ratio was 1.0.

)dfL Tetrabutoxytitanium (manufactured by Sobe Japan, product side B-1)
A solution was prepared by dissolving 0.35 g in 15+aA n-beef sun, and 10 g of blue colored fine particles obtained in the same manner as in Example 2 was added to this solution, and after stirring well with a spatula, The n-hexane was evaporated.

Next, this material was sufficiently ground using a mortar to eliminate any lumps.

On the other hand, as an epoxy resin, solid epoxy with an epoxy equivalent of 480 and a softening point of 68°C (manufactured by Yuka Shell Epoxy ■,
Product name Epicote 1001) 2g in acetone 40v
After adding and dissolving in aA, add 6ra of water to this solution.
A s 10 g of the above colored fine particles and dicyanamide (manufactured by Yuka Shell Epoxy ■, trade name DICY) were used as a hardening agent.
-7) 0.2 g and 2-phenylimidazole-4
After adding 0.2 g of ゜5-diyldimetathool (manufactured by Shikoku Kasei Kogyo, trade name: 2PH2) and thoroughly mixing, the acetone was evaporated with stirring. The dried material was crushed using a mortar to completely loosen the lumps to obtain coated fine particles.

The particle size of the coated fine particles was 1.32 μm. The thickness of the epoxy resin layer was calculated to be 0.05 μm. Observation of the surface of the coated fine particles using a scanning electron microscope revealed that an epoxy resin layer was uniformly formed on the surface of the colored fine particles.

Next, a spray solution was obtained in the same manner as in Example 1 except that the coated fine particles were used, and the spray solution was sprayed onto a glass plate. It was confirmed that the coated fine particles were well dispersed in the form of single particles on the glass plate. The glass plate having the coated fine particles was left in a heating furnace at 150°C for 30 minutes. As in Example 1, when the bonded portion between the glass plate and the coated fine particles was observed using an electron microscope, it was found that a melted epoxy resin layer was present between the glass plate and the colored fine particles. When the residual ratio of particles was determined in the same manner as in Example 1, the residual ratio was 0.95.

A solution was prepared by dissolving OJg of tetrakis(2-ethylhexoxy) titanium (manufactured by Nippon Soda, trade name: TOT) in 15 mJ2 of hexasan. 10 g of red colored fine particles were added thereto, and the mixture was thoroughly stirred using a submersible spoon, and then the n-hexane was evaporated.

Next, this material was sufficiently ground using a mortar to eliminate any lumps.

As a curing agent, 1-cyanoethyl-2-ethyl-4-methylimidazole (manufactured by Shikoku Kasei Kogyo ■, trade name 2E4M) was used.
Z-CN) 0.4 g was used.

Coated fine particles were obtained in the same manner as in Example 4 except that the above materials were used. The particle size of this coated fine particle is 20.77μm
Met. The thickness of the epoxy resin layer was calculated to be 0.25 μm. Observation of the surface of the coated fine particles using a scanning electron microscope revealed that an epoxy resin layer was uniformly formed on the surface of the colored fine particles.

Next, a spray solution was obtained in the same manner as in Example 1 except that the coated fine particles were used, and the spray solution was sprayed onto a glass plate. It was confirmed that the coated fine particles were well dispersed in the form of single particles on the glass plate. The glass plate having the coated fine particles was left in a heating furnace at 110° C. for 30 minutes.

As in Example 1, when the bonded portion between the glass plate and the coated fine particles was observed using an electron microscope, it was found that a melted epoxy resin layer was present between the glass plate and the colored fine particles. When the residual ratio of particles was determined in the same manner as in Example 1, the residual ratio was 0.99.

(Effects of the Invention) According to the present invention, since the epoxy resin layer is provided on the surface of the colored fine particles, the colored fine particles can be adhered to the substrate by heating and melting the epoxy resin layer. Therefore, when the foreign particles of the present invention are used, for example, in a spacer for a liquid crystal display cell, the spacer does not scatter or move from the substrate surface, and the gap between two transparent substrates can be reliably filled almost completely. The quality of the liquid crystal display cell can be improved by keeping it constant.

Furthermore, when a titanium oxide layer with good adhesion, which is assumed to be derived from the rough surface structure, is provided on the surface of the colored fine particles, the epoxy resin composition has good wettability with the titanium oxide layer, so It is sufficient to coat only a monomolecular layer of the resin, and as a result, there is no fear that the spacers will aggregate together, and the epoxy resin layer can be provided on the surface of the colored fine particles with good adhesion.

that's all

Claims (1)

[Claims] 1. Coated fine particles comprising colored fine particles and an epoxy resin layer provided on the surface of the colored fine particles. 2. A method for producing coated fine particles, which includes the step of treating colored fine particles with an epoxy resin composition to form an epoxy resin layer on the surface of the colored fine particles. 3. Coated fine particles comprising colored fine particles, a titanium oxide layer provided on the surface of the colored fine particles, and an epoxy resin layer provided on the surface of the titanium oxide layer. 4. A step of treating colored fine particles with an organic titanate compound to form a titanium oxide layer on the surface of the colored fine particles, and treating the colored fine particles with the titanium oxide layer formed thereon with an epoxy resin composition to form a titanium oxide layer on the surface of the colored fine particles. A method for producing coated fine particles, comprising the step of forming an epoxy resin layer on the surface of an oxide layer.