JP2005200613A - Coated particle, spacer for liquid crystal display element and liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide coated particles excellent in adhesion to a transparent electrode substrate and the like even when pressed to the transparent electrode substrate under a low temperature condition without causing aggregation, a spacer for liquid crystal display elements using the coated particles and the liquid crystal display element. <P>SOLUTION: The coated particles comprise base particles and core shell particles for coating the base particles. The core shell particles comprise core particles and a shell layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to coated particles, a liquid crystal display spacer using the coated particles, and a liquid crystal display element.

Particles in which a part of the surface of the base particle is coated with a resin (hereinafter also referred to as coated particle) are heat resistance, wear resistance, insulation, conductivity, water repellency, adhesiveness, dispersibility on the base particle. It is possible to impart performances such as gloss and coloring, and it is used as various fillers and modifiers in films, pressure-sensitive adhesives, adhesives, paints and the like. Among them, by providing an adhesive coating resin layer on the surface of the base particle having a highly controlled particle size, the coated particles imparted with adhesion to a transparent electrode substrate or the like are spacers for liquid crystal display, When used as a gap material between cell substrates of a fuel cell or the like, it is expected that movement between the substrates does not occur, and the arrangement of the coated particles is less likely to occur.

As such coated particles, for example, Patent Document 1 discloses a coated liquid crystal display spacer in which an adhesive coating layer is formed on the particle surface by graft polymerization. Patent Document 2 discloses mother particles. A spacer for a coated liquid crystal display element in which adhesive child particles smaller than the mother particles are attached to the surface by heating in a high-speed air stream is disclosed, and Patent Document 3 discloses a particle size smaller than the mother particles on the surface of the mother particles. Also disclosed is a coated liquid crystal display spacer obtained by coating a child particle having a different charge sign from that of the mother particle by electrostatic attraction.

However, in the case of the conventional coated particles, it is necessary to contain 50% or more of a polymerizable monomer having a long-chain alkyl group in the thermoplastic resin forming the coating layer in order to firmly fix the coated particle on the glass substrate. For this reason, there has been a problem that the glass transition temperature (Tg) of the coating layer becomes room temperature or lower, which causes coalescence and aggregation of the coated particles. In order to solve this problem, Patent Document 4
Then, Tg by making the content of the polymerizable monomer having a long chain alkyl group less than 50%
Discloses a coated liquid crystal display spacer obtained by using a child particle having a temperature of 50 ° C. or higher and obtained by a method similar to the method disclosed in Patent Document 3. However, since the Tg of the entire coating layer is 50 ° C. or more, in order to obtain sufficient adhesion between the glass substrates, it is necessary to tighten the conditions of thermocompression bonding, and there is a problem that a large burden is placed on the glass substrate. there were.

JP-A-8-328018 Japanese Patent Laid-Open No. 9-235527 JP 2002-131757 A JP 2003-374766 A

In view of the above, the present invention provides coated particles that are excellent in adhesion to a transparent electrode substrate and the like and can be suitably used for spacers for liquid crystal display elements even when pressure-bonded to a transparent electrode substrate or the like under low temperature and low pressure conditions An object of the present invention is to provide a liquid crystal display spacer and a liquid crystal display element using the coated particles.

The present invention is coated particles comprising substrate particles and hollow particles that coat the substrate particles.
The present invention is described in detail below.

The coated particles of the present invention comprise base particles and hollow particles that coat the base particles.
The base particle is not particularly limited, and examples thereof include a structure composed of only a single raw material; a core-shell structure in which a plurality of raw materials are formed in layers. Especially, since various characteristics, such as a mechanical characteristic and an electrical property, can be provided to base material particle | grains, a core-shell structure is suitable.

It does not specifically limit as a material which comprises the said base particle, Well-known inorganic compounds, such as a silica, an organic compound, etc. are mentioned. Among them, when the coated particles of the present invention are used as a liquid crystal display element spacer, it can be deformed at the time of pressure bonding to increase the bonding area, and is excellent in gap stability and adhesion between transparent electrode substrates. Is preferred.

The organic compound is not particularly limited. For example, polyolefins such as polyethylene, polypropylene, polystyrene, polypropylene, polyisobutylene, and polybutadiene, acrylic resins such as polymethyl methacrylate and polymethyl acrylate, polyalkylene terephthalate, polysulfone, polycarbonate, polyamide, Phenolic resins such as phenol formaldehyde resin, melamine resins such as melamine formaldehyde resin, benzoguanamine resins such as benzoguanamine formaldehyde resin, urea formaldehyde resin, epoxy resin, (unsaturated) polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, polyimide, Polyamideimide, polyetheretherketone, Include those consisting of Li ether sulfone. Especially, what uses the resin formed by superposing | polymerizing 1 type, or 2 or more types of various polymerizable monomers which have an ethylenically unsaturated group is preferable from being easy to obtain suitable hardness.

The polymerizable monomer having an ethylenically unsaturated group may be a non-crosslinkable monomer or a crosslinkable monomer.
Examples of the non-crosslinkable monomer include styrene monomers such as styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, chloromethylstyrene; (meth) acrylic acid, maleic acid, Carboxyl group-containing monomers such as maleic anhydride; methyl (meth)
Acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (
(Meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, ethylene glycol (
Alkyl (meth) acrylates such as meth) acrylate, trifluoroethyl (meth) acrylate and pentafluoropropyl (meth) acrylate; 2-hydroxyethyl (
(Meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth)
Oxygen atom-containing (meth) acrylates such as acrylate and glycidyl (meth) acrylate; Nitrile-containing monomers such as (meth) acrylonitrile; Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether and propyl vinyl ether; Vinyl acetate, vinyl butyrate and laurin Acid vinyl esters such as vinyl acid vinyl, vinyl stearate, vinyl fluoride, vinyl chloride and vinyl propionate; and unsaturated hydrocarbons such as ethylene, propylene, butylene, methylpentene, isoprene and butadiene.

Examples of the crosslinkable monomer include tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (
(Meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate; glycerol di (meth) acrylate, polyethylene glycol di (meth) ) Polyfunctional (meth) acrylates such as acrylate and polypropylene glycol di (meth) acrylate; triallyl (iso) cyanurate,
Triallyl trimellitate, divinylbenzene, diallyl phthalate, diallyl acrylamide, diallyl ether, etc .; γ- (meth) acryloxypropyltrimethoxysilane,
Silane-containing monomers such as trimethoxysilylstyrene and vinyltrimethoxysilane; dicarboxylic acids such as phthalic acid; diamines; diallyl phthalate, benzoguanamine, triallyl isocyanate and the like.

The preferable lower limit of the average particle diameter of the substrate particles is 0.5 μm, and the preferable upper limit is 1000 μm. If it is less than 0.5 μm, aggregation is likely to occur during the production of the base particles, and the coated particles produced using the base particles having such a small particle diameter cannot be used as spacers for liquid crystal display elements. Sometimes. If it exceeds 1000 μm, the coated particles of the present invention may not be used as a spacer for a liquid crystal display element.
The average particle size of the substrate particles is obtained by statistically processing the particle size measured using an optical microscope, electron microscope, particle size distribution meter, dynamic light scattering particle size distribution meter, laser diffraction particle size distribution meter, etc. be able to.

The coefficient of variation of the average particle diameter of the substrate particles is preferably 10% or less. When it exceeds 10%, when the obtained coated particles are used as a gap material between substrates such as spacers for liquid crystal display elements, it becomes difficult to arbitrarily control the distance between the transparent electrode substrates facing each other. The coefficient of variation is a numerical value obtained by dividing the standard deviation obtained from the particle size distribution by the average particle size.
The preferable lower limit of the 10% K value of the substrate particles is 1000 MPa, and the preferable upper limit is 15000.
MPa. If it is less than 1000 MPa, the strength of the resulting coated particles is insufficient. Therefore, when the coated particles of the present invention are used for a spacer for a liquid crystal display element, the particles are destroyed when compressed and deformed, and the function as a spacer is achieved. If it exceeds 15000 MPa, the transparent electrode substrate may be damaged if the coated particles of the present invention are used for spacers for liquid crystal display elements. A more preferable lower limit is 2000 MPa, and a more preferable upper limit is 10,000 MP.
a. In addition, the 10% K value is a micro compression tester (for example, PCT-2 manufactured by Shimadzu Corporation).
, Etc.), and the particles are compressed with a smooth indenter end face made of a diamond cylinder having a diameter of 50 μm under a compression rate of 2.6 mN / sec and a maximum test load of 10 g (mm).
Can be obtained by the following formula.

K value ^{(N / mm 2) = (} 3 / √2) · F · S -3/2 · R -1/2
F: Load value at 10% compression deformation of particles (N)
S: Compression displacement (mm) in 10% compression deformation of particles
R: radius of particle (mm)

In order to obtain base particles having a 10% K value satisfying the above conditions, the base particles are preferably made of a resin obtained by polymerizing the above polymerizable monomer having an ethylenically unsaturated group. In this case, it is more preferable to contain at least 20% by weight of a crosslinkable monomer as a constituent component.

The substrate particles preferably have a recovery rate of 20% or more. If it is less than 20%, the resulting coated particles may not be restored to their original shape even when they are deformed, resulting in poor connection. More preferably, it is 40% or more. In addition, the said recovery rate means the recovery rate after applying a 9.8 mN load to particle | grains.

As a method for producing such base particles, conventionally known methods can be used and are not particularly limited. For example, emulsion polymerization, phase inversion emulsion polymerization, suspension polymerization, dispersion polymerization, seed polymerization, Examples include a soap-free precipitation polymerization method. Among these, a seed polymerization method that is excellent in controllability of particle diameter is preferable.
Moreover, what is marketed as the said base particle can also be used.

The seed polymerization is intended to be obtained by monodispersing seed particles synthesized by dispersion polymerization, emulsion polymerization or the like in water, further absorbing the monomer together with an oil-soluble polymerization initiator, and the like. This is a method of polymerizing by heating and the like until the particle size is expanded. The seed polymerization is suitable for the purpose of producing a large amount of fine particles having a specific particle diameter because monodispersed particles can be obtained without classification.

When preparing the base particles by the seed polymerization method, the particle size distribution of the seed particles is also reflected in the particle size distribution of the base particles obtained after the seed polymerization, and is preferably as monodisperse as possible. The value is preferably 10% or less.

The oil-soluble polymerization initiator is not particularly limited, and examples thereof include benzoyl peroxide, lauroyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, 3, 5, 5
Organic peroxides such as trimethylhexanoyl peroxide, t-butylperoxy-2-ethylhexanoate, and di-t-butyl peroxide; azobisisobutyronitrile, azobiscyclohexacarbonitrile, azobis ( 2,4-dimethylvaleronitrile)
An azo compound such as

In the seed polymerization, a surfactant or a dispersion stabilizer may be used as necessary.
As the surfactant, a polymer soluble in the medium, a nonionic surfactant, an ionic surfactant, or the like can be used as appropriate. The dispersion stabilizer is usually a polymer that is soluble in a medium, and examples thereof include polyvinyl alcohol and polyvinyl pyrrolidone.

In the coated particles of the present invention, the substrate particles are coated with hollow particles.
The hollow particles may have a structure in which one large void is formed therein, or a plurality of voids may be formed, and a plurality of small voids may be further formed therein to form a sponge. The resulting structure may be used. Further, when the inside of the hollow particles is sponge-like,
Each space | gap may be mutually connected, may be independent, and these may be mixed. Further, the hollow particles may have voids formed in the inside thereof on the surface.

The porosity of the hollow particles is preferably 10% or more. If it is less than 10%, the effect of coating the base particles with the hollow particles is not so much obtained. If the coated particles of the present invention are used for the spacer for the liquid crystal display element, the base particles and the transparent electrode must be applied unless a high pressure is applied. Hollow particles cannot be completely excluded from the space between the substrate and the transparent electrode substrate may be damaged.
In addition, the said porosity means the ratio of the space | gap part which occupies for the whole volume including the space | gap part of the said hollow particle, The porosity of this hollow particle is particle | grains by a transmission electron microscope (TEM), for example It can be obtained by observing the cross section or measuring the particle specific gravity.

The hollow particles are preferably deformed and / or destroyed when the base particles are deformed by 2%. If it exceeds 2%, it is necessary to carry out under severe pressure bonding conditions when connecting a transparent electrode substrate or the like, which may damage the transparent electrode substrate or the like.
When the coated particles of the present invention in which such hollow particles are coated on the base particles are used as spacers for a liquid crystal display element and a transparent electrode substrate or the like is connected by pressure bonding, the above-mentioned base material even if the pressure bonding conditions are low pressure The hollow particles coated between the particles and the transparent electrode substrate are easily deformed or destroyed, and the amount of the deformed or broken hollow particles remaining between the base material particles and the transparent electrode substrate is small. The base particle and the transparent electrode substrate can be directly connected.

Although it does not specifically limit as a material which comprises the said hollow particle, Since it is easy to deform | transform or destroy when connecting a board | substrate etc. by pressure bonding, it consists of an organic compound.
It does not specifically limit as said organic compound, For example, the organic compound etc. which are used for the above-mentioned base material particle are mentioned.
In addition, as a material which comprises the said hollow particle, it is not limited to the said organic compound, For example, you may consist of inorganic compounds, such as a silica.

When the coated particle of the present invention is used as a spacer for a liquid crystal display element, the material constituting the hollow particle has adhesiveness and is softened under temperature conditions when the liquid crystal display element is pressed against cell glass. It is preferable that it adheres to the cell glass depending on the temperature conditions during pressure bonding and does not contaminate the liquid crystal or the like. This is because when the coated particles of the present invention are used as spacers for liquid crystal display elements, it is possible to obtain strong adhesion to cell glass without contaminating the liquid crystals.

It does not specifically limit as a method to manufacture the said hollow particle, It can manufacture by a well-known method. Examples thereof include a mini-emulsion polymerization method, an emulsion polymerization method, a phase inversion emulsion polymerization, a micro suspension polymerization method, a suspension polymerization method, a dispersion polymerization method, a seed polymerization method, and a soap-free precipitation polymerization method. Among these, a mini-emulsion polymerization method or a seed polymerization method that is excellent in controllability of the hollow ratio is preferably used. Moreover, what is marketed as a hollow particle can also be used.

The particle diameter of the hollow particles varies depending on the particle diameter of the base particle and the application of the coated particle of the present invention, but is preferably 1/10 or less of the particle diameter of the base particle. If it exceeds 1/10, the physical properties of the base particles may be governed by the physical properties of the hollow particles, and the effect of using the base particles may be difficult to obtain. More preferably, the lower limit of the particle diameter of the hollow particles is 10 nm.
The preferred upper limit is 2000 nm.
Moreover, when the particle diameter of the hollow particles is 1/10 or less of the base material particles, the hollow particles are efficiently adsorbed on the base particles when the coated particles of the present invention are produced by the heteroaggregation method described later. Can be made.
In addition, since small hollow particles enter a gap covered with large hollow particles and the coating density can be improved, two or more kinds of hollow particles having different particle diameters may be used in combination. At this time, the particle diameter of the small hollow particles is preferably ½ or less of the particle diameter of the large hollow particles, and the number of small hollow particles is preferably ¼ or less of the number of large hollow particles. .

The hollow particles preferably have a particle diameter CV value of 20% or less. When it exceeds 20%, the thickness of the coating layer of the resulting coated particles becomes non-uniform, and when the coated particles of the present invention are used as a gap material between substrates such as spacers for liquid crystal display elements, they are pressure-bonded between transparent electrodes. In this case, it becomes difficult to apply pressure uniformly, which may cause improper fixing. The CV value of the particle diameter can be calculated by the following formula.
CV value of particle diameter (%) = standard deviation of particle diameter / average particle diameter × 100
As a method for measuring the particle size distribution, it can be measured with a particle size distribution meter or the like before coating the substrate particles, but after coating, it can be measured by image analysis of an SEM photograph or the like.

The coated particles of the present invention are such that the hollow particles are coated on the surface of the substrate particles. The hollow particles have a surface area of 20% or less in contact with the surface of the substrate surface particles. Preferably it is. If it exceeds 20%, the deformation of the hollow particles is large, and the thickness of the coating layer of the resulting coated particles may be non-uniform. The lower limit is not particularly limited, and the hollow particles and the base particles Is, for example, substantially 0 when it is connected by a polymer having a long chain length.
%.

In the coated particles of the present invention, it is preferable that 5% or more of the surface of the substrate particles is coated with the hollow particles. If it is less than 5%, sufficient adhesion cannot be obtained.
In addition, the coverage with the hollow particles on the surface of the base particles is defined by the addition amount (concentration) of the hollow particles, the charge density of the surface of the hollow particles, the amount of functional groups (density) introduced to the surface of the base particles, water, and / or It can be controlled by the pH and / or ionic strength of the organic solvent.

The hollow particles are preferably coated with a single layer on the surface of the substrate particles. By controlling the particle diameter of the hollow particles, the particle diameter of the coated particles of the present invention can be easily made uniform, and when connecting the transparent electrode substrate or the like by pressure bonding using the coated particles of the present invention. The pressure applied to the coated particles can be made uniform, and the coated particles of the present invention and the transparent electrode substrate can be reliably fixed.

In the coated particles of the present invention, the method for bonding the hollow particles and the base particles is not particularly limited, and either physical adsorption or chemical adsorption may be used. Examples of the physical adsorption method include dry methods such as a high-speed stirrer and a hybridizer. However,
When hollow particles are introduced onto the surface of the substrate particles by a dry method using the high-speed stirrer, a hybridizer, or the like, a load such as an excessive pressure or frictional heat is easily applied. At this time, the hollow particles are deformed or destroyed by impact and frictional heat with the base particles, and the coating particle thickness becomes non-uniform,
The hollow particles and the base particles may be chemically bonded, and more preferably covalently bonded, because the hollow particles may be laminated and the control of the coating thickness may be difficult. . When the hollow particles and the base particles are chemically bonded, the binding force is stronger than that by only van der Waals force or electrostatic force, and the hollow particles can be prevented from peeling off from the base particles. . Moreover, since this chemical bond is formed only between the base particles and the hollow particles, and the hollow particles are not bonded to each other, the coating layer of the hollow particles is a single layer. From this, if the thing with a uniform particle diameter is used as a base particle and a hollow particle, the particle diameter of the covering particle | grains of this invention can be made uniform easily.

Examples of the method for covalently bonding the hollow particles to the base particles include base particles having NH ₂ groups on the surface (for example, divinylbenzene obtained by suspension polymerization using polyallylamine as a dispersion stabilizer). For example, a method of reacting an epoxy group of a hollow particle having an epoxy group on the surface obtained by miniemulsion polymerization or the like with the NH ₂ group on the surface of the main particle).

In the coated particles of the present invention, the surface of the substrate particles is preferably coated with a single layer by hollow particles. When it is a single layer, the particle size of the coated particles can be easily controlled. In addition, as a method of coating the surface of the substrate particle with a single layer with the hollow particles, the heteroaggregation method described later is preferable.

The method for producing the coated particles of the present invention is not particularly limited. For example, electrostatic interaction, dry blending method, melt dispersion cooling method, solution dispersion drying method, heteroaggregation method, spray drying method, interfacial polymerization method, etc. Examples thereof include a method in which hollow particles are introduced on the surface of the substrate particles, and the hollow particles and the substrate particles are chemically bonded. When the surface of the substrate particles is made of a conductive metal and is coated with a single layer of hollow particles, a heteroaggregation method is suitably used when introducing the hollow particles.

In the heteroaggregation method, the hollow particles can be uniformly coated on the surface of the base particles made of a conductive metal by aggregating the hollow particles on the surface of the base particles in water and / or an organic solvent. In addition, the presence of water and / or organic solvent causes a rapid chemical reaction between the functional group introduced to the surface of the base particle or the surface of the base particle due to the solvent effect and the functional group of the hollow particle. Is not required, and the temperature of the entire system is easily controlled, so the load on the base particles is reduced. In addition, the problem that the hollow particles are deformed or broken by excessive heat is less likely to occur, and the accuracy of the coating becomes extremely high.
The organic solvent is not particularly limited as long as it does not dissolve the hollow particles.

The coated particles of the present invention enclose 1 g of coated particles and 10 mL of ultrapure water in a quartz tube,
When extracted for 24 hours, the concentration of ions extracted in the ultrapure water is preferably 10 ppm or less. If it exceeds 10 ppm, when the coated particles of the present invention are used as spacers for liquid crystal display elements, the liquid crystal may be contaminated by ionic components or the like resulting from the coated particles.
A method for achieving the concentration of ions to be extracted is not particularly limited, and examples thereof include a method for producing the base particles constituting the coated particles or the hollow particles to be coated by the following method.

That is, a polymerizable composition containing a polymerizable monomer containing a polymerizable monomer having an ionic functional group and a polymerizable composition containing a nonionic polymerization initiator are polymerized in a state of being uniformly dispersed in water, and are then applied to the surface. Resin fine particles to be a base resin or hollow particles having an ionic functional group are obtained. Further, the surface of the coated particle is prepared after the base particle or the hollow particle to be coated is prepared by the method of converting the ionic functional group of the obtained resin fine particle to the nonionic functional group, or the base particle is coated with the hollow particle. The ionic functional group is converted into a nonionic functional group.

Since the coated particles of the present invention are those in which the surface of the base particles is coated with hollow particles that are easily softened / deformed, a material having a high glass transition temperature (Tg) may be used as the material of the hollow particles. As a result, it does not cause aggregation and has excellent long-term stability.
In addition, even when pressure bonding to a transparent electrode substrate or the like is performed under low-temperature and low-pressure conditions, the hollow particles are easily softened and deformed to act as a fixing agent between the base particle and the transparent electrode substrate. It can be made excellent in adhesion between the electrode substrate and the coated particles. Moreover, since the amount of the resin constituting the hollow particles protruding from between the base material particles and the transparent electrode substrate is reduced by using the hollow particles, the apparent particle diameter of the base material particles is not increased more than necessary. Liquid crystal contamination due to resin is less likely to occur.

Further, when the hollow particles of the coated particles of the present invention are covalently bonded to the base particles, it is possible to prevent the hollow particles from being peeled off from the surface of the base particles, and to obtain coated particles having a uniform particle size. Can do.
Further, when 1 g of the coated particles of the present invention and 10 mL of ultrapure water are sealed in a quartz tube and extracted at 120 ° C. for 24 hours, the concentration of ions extracted into the ultrapure water is 10 ppm or less. When manufacturing a liquid crystal display element using the coated particles of the present invention as a spacer for a liquid crystal display element,
Even when the liquid crystal display element spacer and the liquid crystal are directly contacted with each other, the liquid crystal is contaminated because the liquid crystal display element spacer component does not elute into the liquid crystal as ions. Absent.
The spacer for liquid crystal display elements using the coated particles of the present invention is also one aspect of the present invention.
Furthermore, the liquid crystal display element using the spacer for liquid crystal display elements of this invention is also 1 of this invention.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

(Synthesis Example 1)
10000 parts by weight of ion exchange water, polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Co., Ltd., “GH-2
0 ") 30 parts by weight and polyallylamine (manufactured by Nittobo," PPA-H-10C ") 1
A mixture of 100 parts by weight of divinylbenzene and 1 part by weight of benzoyl peroxide was dispersed in 0 part by weight of the solution using an SPG membrane having a pore diameter of about 0.8 micrometers, and polymerization was performed at 90 ° C. for 10 hours. After washing, classification was performed to obtain base particles having an amino group on the surface having an average particle diameter of 5 μm (CV value 5%).

(Synthesis Example 2)
To 10 parts by weight of dodecyl mercaptan, 95 parts by weight of styrene, 5 parts by weight of dimethylaminopropylacrylamide, 1000 parts by weight of ion-exchanged water, 1 part by weight of AIBA and 1 part by weight of dodecyltrimethylammonium chloride are added and polymerized at 70 ° C. for 8 hours. Average particle size 80
A latex dispersion having a nm (CV value of 10%) was obtained. Using this latex as seed particles,
10 parts by weight of this latex in solid content, 2 parts by weight of dodecyltrimethylammonium chloride, and 1 part by weight of AIBA were dispersed in 900 parts by weight of ion-exchanged water. When a mixture of 40 parts by weight of methyl methacrylate, 20 parts by weight of glycidyl methacrylate, 30 parts by weight of styrene and 10 parts by weight of divinylbenzene was added and stirred for 48 hours at room temperature, most of the above substances were absorbed by the seed particles. It was done. Subsequently, when this was polymerized at 60 ° C. for 6 hours, a dispersion of hollow particles (1) having an average particle diameter of 180 nm (CV value 10%) was obtained.
When this particle dispersion was dried and observed with a transmission electron microscope, the central portion of the particles was transparent and the inner diameter was 90 nm (hollow rate 12.5%). Moreover, the glass transition temperature (Tg) of this particle | grain was 107 degreeC. The hollow particle (1) dispersion was replaced with acetone by centrifugation to obtain an acetone dispersion (1) of the hollow particles (1).

(Synthesis Example 3)
Latex obtained in the same manner as in Synthesis Example 2 was used as seed particles, and this latex was solid content of 1
0 parts by weight and 2 parts by weight of dodecyltrimethylammonium chloride were added to ion-exchanged water 900.
Dispersed in parts by weight. To this, 40 parts by weight of methyl methacrylate, 20 parts by weight of glycidyl methacrylate, 30 parts by weight of styrene, 1 part by weight of benzoyl peroxide, 1 divinylbenzene
When a mixture of 0 part by weight and 40 parts by weight of ethanol was added and stirred at room temperature for 48 hours, most of the substance was absorbed by the seed particles. Subsequently, when this was polymerized at 60 ° C. for 6 hours, a dispersion of solid particles (1) having an average particle size of 160 nm (CV value of 10%) was obtained.
When this particle dispersion was dried and observed with a transmission electron microscope, no voids were observed in the particles. Moreover, the glass transition temperature (Tg) of this particle | grain was 107 degreeC. The solid particle (1) dispersion was replaced with acetone by centrifugation to obtain an acetone dispersion (1) of solid particles (1).

(Example 1)
10 parts by weight of the base particles obtained in Synthesis Example 1 are dispersed in acetone, and 10 parts by weight of solid dispersion of acetone dispersion (1) of the hollow particles (1) obtained in Synthesis Example 2 is added at room temperature. Stir for 3 hours. After filtration, it was further washed with acetone and dried to obtain coated particles (1).

(Comparative Example 1)
10 parts by weight of the base material particles obtained in Synthesis Example 1 were dispersed in acetone, and 10 parts by weight of solid dispersion (1) of the solid particles (1) obtained in Synthesis Example 3 was added at a solid content. For 3 hours. After filtration, it was further washed with acetone and dried to obtain coated particles (2).

(Observation of coating state)
The coated particles (1) and (2) obtained in Example 1 and Comparative Example 1 were scanned with a scanning electron microscope (SEM).
When the surface was observed, the hollow particles (1) of the coated particles (1) and the solid particles (1) of the coated particles (2) were both coated with a single layer on the surface of the substrate particles.

(Evaluation of adhesiveness)
Each of the coated particles (1) and (2) obtained in Example 1 and Comparative Example 1 was dispersed on the surface of a transparent electrode plate for a liquid crystal panel, and sandwiched between the same transparent electrode plates, and then 120 ° C. on a hot plate.
And heated for 30 minutes. Thereafter, the transparent electrode on the non-heated surface was removed, and an air blow test was performed. In this air blow test, after measuring the number of coated particles in a predetermined region using an optical microscope, an air gun (0.3 MPa) is used to remove air from a distance of 10 cm from the surface of the transparent electrode substrate for a liquid crystal panel. It sprayed for 2 seconds, the number of the covering particles which remained in the predetermined area was re-measured, and the value by the following formula was made into the air blow residual rate.

Air blow residual ratio = (number of particles after air blow) / (number of particles before air blow)
) × 100

As a result, the air blow residual rate of the coated particles (1) according to Example 1 is as high as 98%,
The air blow residual ratio of the coated particles (2) according to Comparative Example 1 was 63%, whereas it was fixed.
It was very low and the adhesiveness was low.

Since the present invention is constituted as described above, it is excellent in adhesion to a transparent electrode substrate or the like even if it is pressure-bonded to the transparent electrode substrate or the like under low temperature and low pressure conditions, and can be suitably used for a liquid crystal display element spacer or the like. It is possible to provide a coated particle that can be produced, a spacer for liquid crystal display and a liquid crystal display element using the coated particle.

Claims (8)

A coated particle comprising substrate particles and hollow particles covering the substrate particles. The coated particles according to claim 1, wherein the hollow particles are deformed and / or broken when the base particles are deformed by 2%. The coated particles according to claim 1 or 2, wherein the hollow particles have a porosity of 10% or more. 4. The coated particle according to claim 1, 2, or 3, wherein the base particle and the hollow particle are made of an organic compound. The surface of the base particle is covered with a single layer by hollow particles, 1, 2,
3. Coated particles according to 3 or 4. 1 g of coated particles and 10 mL of ultrapure water are sealed in a quartz tube, and when extracted at 120 ° C. for 24 hours, the concentration of ions extracted into the ultrapure water is 10 ppm or less. Item 6. The coated particle according to Item 1, 2, 3, 4 or 5. A spacer for a liquid crystal display element, comprising the coated particles according to claim 1, 2, 3, 4, 5 or 6. A liquid crystal display element comprising the spacer for a liquid crystal display element according to claim 7.