JP2005240006A - Coating composition, coated item, optical member and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a coating composition which can provide a coated item having an excellent dispersion stability of particles and excellent optical diffusivity. <P>SOLUTION: The coating composition is obtained by blending composite particles with a binder solution containing a binder resin and a solvent. The composite particles comprise polymer particles derived from a polymerizable vinyl monomer and a silica film provided on the surfaces of the polymer particles so as to expose at least a part of the surfaces of the polymer particles. The silica film comprises a condensate of a polyalkoxysiloxane oligomer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention mainly relates to a coating composition in which particles are blended in a binder solution containing a binder resin and a solvent, a coated product using the same, an optical member, and the like.

Conventionally, as a coating composition, a mixture of particles has been used to achieve various purposes by utilizing the light diffusibility of the particles.
For example, for the purpose of matting the surface of various molded products, a mixture of inorganic particles such as silica particles or organic polymer particles (resin particles) is used. According to such a coating composition, irregularities are formed on the surface of the coating film, and the reflection of light is diffused, so that the surface is matte.

  Further, in image display devices used in televisions, personal computers, electronic notebooks, mobile phones, amusement devices, etc., optical sheets that diffuse transmitted light and reflected light are used as light diffusion sheets and antiglare sheets. Even in such an optical sheet, a composition containing inorganic particles and resin particles is used as a coating composition for forming a coating film on the surface in order to diffuse transmitted light and reflected light.

  For example, in a light diffusing sheet that diffuses transmitted light, a composition in which inorganic particles such as calcium carbonate and silica and organic polymer particles such as polystyrene and silicone are blended is used as a coating composition. .

However, in the coating composition containing the inorganic particles as described above, the dispersion stability in the binder solution, in particular, the binder solution using a transparent binder such as polymethyl methacrylate resin as the binder resin is low. There's a problem.
Further, the coating composition containing the organic polymer particles as described above has a problem that the dispersion stability is good but sufficient light diffusibility cannot be obtained.

For this problem, as organic polymer particles having high light diffusibility, polymer particles containing smectite (the following Patent Document 1) and composite particles in which silica particles of 500 nm or less are dispersed in resin particles (the following Patent) Document 2) has been proposed.
Japanese Patent No. 3040705 Japanese Patent Laid-Open No. 10-265580

However, even if any of the above particles is used as the blended particles, it is still difficult to say that a coated product having excellent light diffusibility can be provided.
Accordingly, in view of the above problems, the present invention provides a coating composition that can provide a coated product that is excellent in dispersion stability of particles and that is excellent in light diffusibility, and a coated product coated with the coating composition. The task is to do.

As a result of intensive studies in view of the above problems, the present inventors have found that the above problems can be solved by the following means, and have solved the present invention.
That is, the present invention is a coating composition in which composite particles are blended in a binder solution containing a binder resin and a solvent,
The composite particles include polymer particles derived from a polymerizable vinyl monomer, and a silica coating provided so that at least a part of the surface is exposed on the surface of the polymer particles, and the silica coating is a polyalkoxysiloxane. A coating composition comprising an oligomer condensate is provided.

  In the coating composition of the present invention, the action is not clear, but the composite particle and the binder are provided so that at least a part of the surface of the polymer particle is exposed. Familiarity with the resin is good, and the dispersion stability is excellent. Further, in addition to the light diffusibility originally exhibited by the silica particles, it is considered that at least a part of the surface is exposed, so that complex reflection and refraction of light occurs, and more excellent light diffusibility is expressed.

In the present invention, the silica coating has an opening ratio of 0.1 to 1, and the relationship of 0.5 ≦ h / D <1 between the height h of the silica coating and the diameter D of the composite particles. It is preferable that the polymer particles are coated so that the surface of the polymer particles is exposed so as to have the following.
When the aperture ratio of the silica coating is less than 0.1, there is a possibility that the light diffusion and reflection properties are relatively poor. When the aperture ratio exceeds 1, the coating is easily peeled off. A more preferable aperture ratio is 0.1 to 0.8.
The composite particles having an opening ratio of 1 means that the silica coating covers almost half of the polymer particles.
Further, when h / D is 1 or more, the light diffusion and reflectance may be relatively poor, and when h / D is less than 0.5, the film tends to peel off.
In addition, an aperture ratio and h / D are measured by the method as described in an Example.

  The present invention also provides a coated product obtained by coating such a coating composition on a substrate, an optical member coated on a transparent substrate, and a liquid crystal display using the optical member.

  As described above, the coating composition of the present invention can provide a coated product having excellent particle dispersion stability and excellent light diffusibility.

Hereinafter, preferred embodiments of the present invention will be described.
The coating resin composition of this embodiment is obtained by blending composite particles in a binder solution containing a binder resin and a solvent.
The composite particles are composed of polymer particles derived from a polymerizable vinyl monomer and a silica coating provided on the surface of the polymer particles, and the silica coating is composed of a polyalkoxysiloxane oligomer condensate, preferably spherical. Or it is made into the substantially spherical shape.

FIG. 1 is a schematic cross-sectional view showing the composite particle of the present embodiment.
The silica coating 2b is composed of a polyalkoxysiloxane oligomer condensate, and is provided such that the surface of the polymer particles 2a is exposed as shown in FIG. 1, and has anisotropy.
Specifically, the polymer particles have an aperture ratio of 0.1 to 1 and the height h of the silica coating and the diameter D of the composite particles have a relationship of 0.5 ≦ h / D <1. The polymer particles are coated by exposing the surface of the polymer.
With such a configuration, for example, the reflection and refraction of complex light is more complicated than non-anisotropic particles such as spherical particles of silica alone or spherical composite particles in which the surface of polymer particles is completely covered with silica. Occurs, and more excellent light diffusibility can be expressed.

The polymer particles are obtained by polymerizing a polymerizable vinyl monomer.
Examples of the polymerizable vinyl monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, and p-tert-butyl. Styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, n-methoxy styrene, p-phenyl styrene, p-chloro Styrene and derivatives thereof such as styrene and 3,4-dichlorostyrene,
Ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, isobutylene,
Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride,
Vinyl esters such as vinyl acetate, vinyl propionate and vinyl butyrate,
Methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, 2-acrylate Chlorethyl, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate , Stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethyl methacrylate α- methylene aliphatic monocarboxylic acid esters such as aminoethyl,
One type of acrylic acid or methacrylic acid derivative such as acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, etc. Or two or more,
In some cases, acrylic acid, methacrylic acid, maleic acid, fumaric acid and the like can also be used.

  Further, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone, N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl compounds such as N-vinylpyrrolidone, vinyl naphthalene salts, and the like can be used alone or in combination of two or more in a range not impeding the effects of the present invention.

Among these, styrene or methacrylic acid derivatives that are inexpensive in terms of cost are preferable.
The polymer particles may or may not be crosslinked, but are preferably crosslinked when solvent resistance is required.
Examples of the monomer used for crosslinking include monomers having two or more functional groups such as a polymerizable vinyl monomer such as ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and divinylbenzene.

  The polymer particles may contain, for example, various additives such as an ultraviolet absorber, a heat stabilizer, and a colorant as long as the amount is less than 1 part by weight with respect to 100 parts by weight of the resin component.

  The silica coating is composed of a polyalkoxysiloxane oligomer condensate as described above. Examples of the polyalkoxysiloxane oligomer include those having the following structural formula.

Examples thereof include oligomers such as polymethoxysiloxane, polyethoxysiloxane, polypropoxysiloxane, and polybutoxysiloxane.
Among these, polymethoxysiloxane oligomers and polybutoxysiloxane oligomers which are poorly water-soluble and have good phase separation from the resin are preferable, and in particular, polymethoxysiloxane oligomers and polybutoxysiloxane oligomers having a weight average molecular weight of 300 to 3000 are preferable. preferable.
In addition, a weight average molecular weight is measured on condition of the following using GPC.
Column: “TSK GEL” (manufactured by Tosoh Corporation)
G-1000H,
G-2000H
G-4000H
Effluent: Tetrahydrofuran Outflow rate: 1 ml / min Outflow temperature: 40 ° C

  In the case of low molecular weight alkoxysiloxanes such as tetramethoxysilane and tetraethoxysilane in which n = 1 to 2 in the above molecular formula, in the production of composite particles to be described later, water is dissolved during functional group hydrolysis (condensation). Therefore, it is difficult and difficult to make it stably present in the monomer droplets. In addition, polyalkoxysiloxane oligomers in which n = 40 or more in the above molecular formula is not preferable because the condensability and compatibility with the polymerizable vinyl monomer are reduced.

  In the present invention, it is preferable that the polymerizable vinyl monomer is a styrene or methacrylic acid derivative and the alkoxysiloxane oligomer is a polymethoxysiloxane oligomer or a polybutoxysiloxane oligomer.

  In addition, hydrolyzable alkoxy metal compounds other than silicon-based compounds may be added to these polyalkoxysiloxane oligomer condensates for the purpose of adding functions such as ultraviolet absorption.

In the composite particles of the present invention, the ratio of the polymer particles to the silica coating is preferably 10 to 500 parts by weight, and more preferably 20 to 300 parts by weight with respect to 100 parts by weight of the polymer particles.
Such composite particles can be obtained, for example, by adjusting the mixing ratio of each monomer in such a range when the monomer composition of the polymerizable vinyl monomer and the polyalkoxysiloxane oligomer is adjusted in the composite particle manufacturing method described later. Adjusted.

The composite particles usually have a particle diameter of 1 to 100 μm, preferably 3 to 50 μm, more preferably 3 to 30 μm.
If the particle diameter of the composite particles is less than 1 μm, sufficient light reflection characteristics may not be obtained, and if it exceeds 100 μm, the appearance of the coated product may be deteriorated.
The particle diameter of the composite particles depends on the mixing conditions of the monomer composition and water, the addition amount of the suspension stability and surfactant, the stirring conditions of the above stirrer, and the dispersion conditions in the composite particle manufacturing method described later. It can be adjusted by adjusting.

As the binder resin constituting the binder solution, a thermoplastic resin is usually used. Examples of the thermoplastic resin include (meth) acrylic resin, (meth) acrylic acid alkyl-styrene copolymer resin, polycarbonate resin, Examples thereof include polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, silicone resin, urethane resin, epoxy resin, melamine resin, vinyl acetate resin, phenol resin, resorcin resin, and butadiene acrylonitrile rubber.
Among these, in the case where excellent transparency is required for a member after coating, such as a coating composition for an optical member, (meth) acrylic resin, (meth) acrylic acid alkyl-styrene copolymer resin, polycarbonate Resins and polyester resins are preferred. These thermoplastic resins can be used alone or in combination of two or more.

The solvent constituting the binder solution is not particularly limited as long as there is no problem with the solubility or dispersibility of the binder resin. For example, n-butane, n-hexane, n-heptane, n-octane, isononane, n- Hydrocarbon solvents such as decane, n-dodecane, cyclopentane, cyclohexane, cyclobutane,
Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, ether alcohol solvents such as ethyl acetate, butyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether,
Alcohol solvents such as ethanol, isopropanol, n-butanol, isobutanol,
One type or two or more types of aromatic solvents such as toluene, xylene, and catechol, and water can be used.
In an aqueous binder solution using water or an alcohol solvent, the binder resin does not need to be completely dissolved in the solvent, and may be dispersed in the form of an emulsion or a dispersion.
Among the above examples, particularly preferable solvents include methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, and toluene in consideration of the solubility of the binder resin and the drying speed after coating. As the water-based emulsion or dispersion, an acrylic or polyester-based emulsion or dispersion is easily available and the transparency of the resin is high, which is preferable.

In the coating composition of the present invention, the compounding amount of the composite particles is usually 1 to 150 parts by weight, preferably 1 to 120 parts by weight with respect to 100 parts by weight of the binder resin.
If it is 1 part by weight or more, sufficient light diffusibility and light reflection characteristics can be obtained, and if it is 150 parts by weight or less, the dispersion stability of the composite particles and the adhesion to an object to be coated such as a substrate are lowered. There is no fear.
In addition, when the object to be coated is a transparent base material and is a diffusion sheet that diffuses transmitted light by being applied to the transparent base material, the compounding amount of the composite particles in the coating composition is preferably a binder resin. It is 20-120 weight part with respect to 100 weight part, More preferably, it is 20-100 weight part. Moreover, when setting it as the glare-proof sheet which diffuses reflected light, Preferably it is 1-30 weight part, More preferably, it is 5-30 weight part.
The amount of the solvent is not particularly limited as long as the binder resin is dissolved or dispersed sufficiently uniformly and the composite particles can be dispersed sufficiently uniformly, but is 100 to 1000 parts by weight with respect to 100 parts by weight of the binder resin. Is preferred. If the amount is less than 100 parts by weight, the binder resin may not be dissolved or dispersed sufficiently uniformly. If the amount exceeds 1000 parts by weight, the viscosity of the coating composition is significantly reduced. Production of the film becomes difficult.

In the coating composition of the present invention, in order to impart functions such as gloss, opacity, and color to the coated film after coating, titanium oxide, zinc oxide, zirconium oxide, magnesium oxide, iron oxide, hydroxide Iron, chromium oxide, chromium hydroxide, ultramarine, bitumen, manganese violet, ultramarine purple, titanium black, carbon black, aluminum powder, titanium mica, bismuth oxychloride, iron oxide-treated mica titanium, bituminized mica titanium, carmine-treated mica titanium , Inorganic pigments such as silica, calcium carbonate, magnesium carbonate, barium sulfate, barium silicate, calcium silicate, magnesium silicate, calcium phosphate, hydroxyapatite, zeolite, alumina, talc, mica, bentonite, kaolin, sericite,
Organic pigments such as aluminum lakes such as tartrazine, sunset erotic FCF, brilliant blue FCF, zirconium lake, barium lake, herringdon pink CN, risol rubin BCA, lake red CBA, phthalocyanine blue, permanent orange, etc. may be blended. .
The blending amount of the pigment is preferably 1 to 80 parts by weight with respect to 100 parts by weight of the binder resin.
If the amount is less than 1 part by weight, the effect of a pigment such as coloring cannot be obtained, and if it exceeds 80 parts by weight, a coating film having a high appearance cannot be obtained.
However, it is preferable that the coating composition for an optical member does not contain a pigment.

  The coating composition of the present invention may be blended with resin particles (polymer single particles) or inorganic particles (inorganic single particles) as long as the effect is not inhibited.

  The coating composition of the present invention is configured as described above. Next, a preferred method for producing the coating composition will be described in steps (1) to (4).

(1) (Preparation of monomer composition)
First, in addition to a polymerizable vinyl monomer and a polyalkoxysiloxane oligomer, a polymerization initiator for polymerizing the polymerizable vinyl monomer and other components are blended to prepare a monomer composition.
Here, as the polymerizable vinyl monomer and the polyalkoxysiloxane oligomer, those described above can be used.
The blending amount of the polyalkoxysiloxane oligomer is appropriately adjusted so as to obtain a desired opening ratio and h / D, but the viewpoint that the opening ratio is 0.1 to 1 and 0.5 ≦ h / D <1 is likely to be obtained. Therefore, 10 to 500 parts by weight is preferable with respect to 100 parts by weight of the polymerizable vinyl monomer, and more preferably 20 to 300 parts by weight. When the amount is less than 10 parts by weight, it is difficult to cover the coating state with a predetermined opening ratio and h / D. When the amount is more than 500 parts by weight, the polymer particles are hardly exposed, which is not preferable.

As the polymerization initiator, for example, an oil-soluble peroxide polymerization initiator or azo polymerization initiator used for aqueous suspension polymerization can be used.
Specific examples include benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, orthochloroperoxybenzoic acid, orthomethoxybenzoic acid peroxide, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, cumene hydroperoxide, cyclohexanone peroxide, t-butyl. Peroxide polymerization initiators such as hydroperoxide and diisopropylbenzene hydroperoxide, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2 '-Azobis (2,3-dimethylbutyronitrile), 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,3,3-trimethylbutyronitrile) 2,2 '-Azobis (2-isopropylbutyronitrile 1,1′-azobis (cyclohexane-1-carbonitrile) 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile, (2-carbamoylazo) isobutyronitrile, 4,4′- Examples thereof include azo initiators such as azobis (4-cyanovaleric acid) and dimethyl-2,2′-azobisisobutyrate.

Among these, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), benzoyl peroxide, lauroyl peroxide have a high decomposition rate of the polymerization initiator, etc. This is preferable.
The addition amount of the polymerization initiator is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the polymerizable vinyl monomer.

(2) (Production of composite particles)
Next, using the prepared monomer composition, for example, by performing aqueous suspension polymerization in an aqueous medium, a polymerizable vinyl monomer is polymerized, and further, polyalkoxysiloxane is condensed to form composite particles.
Specifically, first, as the aqueous medium, water or a mixed medium of water and a water-soluble solvent such as alcohol is used.
In order to stabilize the suspension polymerized particles, the amount of the aqueous medium used is usually preferably 100 to 1000 parts by weight with respect to 100 parts by weight of the total of the polymerizable vinyl monomer and the polyalkoxysiloxane oligomer. .

In order to suppress the generation of emulsified particles in the aqueous medium, water-soluble polymerization prohibition such as nitrites, sulfites, hydroquinones, ascorbic acids, water-soluble vitamin Bs, citric acid and polyphenols is prohibited. An agent may be added.
Furthermore, you may add a suspension stabilizer as needed. Examples of the suspension stabilizer include phosphates such as calcium phosphate, magnesium phosphate, aluminum phosphate and zinc phosphate, pyrophosphates such as calcium pyrophosphate, magnesium pyrophosphate, aluminum pyrophosphate and zinc pyrophosphate, calcium carbonate And dispersion stabilizers of poorly water-soluble inorganic compounds such as magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, and colloidal silica. Among these, tribasic calcium phosphate, magnesium pyrophosphate, calcium pyrophosphate, and colloidal silica obtained by the metathesis method are preferable because polymer particles can be stably obtained.

The suspension stabilizer can be used in combination with a surfactant such as an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant.
Examples of the anionic surfactant include fatty acid oils such as sodium oleate and castor oil potassium, alkyl sulfate salts such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkylnaphthalene sulfone. Acid salts, alkane sulfonates, dialkyl sulfosuccinates, alkyl phosphate esters, naphthalene sulfonate formalin condensates, polyoxyethylene alkyl phenyl ether sulfates, polyoxyethylene alkyl sulfates and the like.

  Nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, oxy Examples include ethylene-oxypropylene block polymers.

  Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride.

  Examples of the zwitterionic surfactant include lauryl dimethylamine oxide and phosphate ester or phosphite ester surfactants.

  These suspension stabilizers and surfactants are used alone or in combination of two or more. Considering the particle diameter of the resulting polymer particles and the dispersion stability during polymerization, the selection and use amount of the suspension stabilizer is appropriately adjusted and used. Usually, the addition amount of the suspension stabilizer is 0.5 to 15 parts by weight with respect to 100 parts by weight of the polymerizable vinyl monomer, and the addition amount of the surfactant is 0.001 to 0.003 with respect to 100 parts by weight of the aqueous medium. 1 part by weight.

In this way, the monomer composition is added and dispersed in the aqueous medium to which various additives are added.
As a method for dispersing the monomer composition, for example, a method in which the monomer composition is directly added to an aqueous medium and dispersed in the aqueous medium as monomer droplets by stirring force of a propeller blade or the like, a high shear force composed of a rotor and a stator is used. It is possible to adopt a method of dispersing using a homomixer that is a disperser that uses the above, an ultrasonic disperser, or the like. In addition, as a preferable method for making the particle diameters substantially uniform, a high-pressure disperser or a MPG (microporous glass) porous film utilizing collision force between monomer droplets such as a microfluidizer or nanomizer or a collision force against the machine wall. A method such as press-fitting the monomer composition into an aqueous medium can also be employed.
In addition, the monomer composition in an aqueous medium becomes spherical normally as a monomer droplet by dispersion | distribution.

Next, suspension polymerization is started by heating the aqueous medium in which the monomer composition is dispersed.
The aqueous medium is preferably stirred during the polymerization reaction. For example, the stirring may be performed so gently as to prevent the monomer droplets from floating and the particles after polymerization from being settled. In suspension polymerization, the polymerization temperature is preferably about 30 to 100 ° C, more preferably about 40 to 80 ° C. The time for maintaining this polymerization temperature is preferably about 0.1 to 20 hours.
In addition, when the boiling point of the polymerizable vinyl monomer and the polyalkoxysiloxane oligomer is near the polymerization temperature or higher than the polymerization temperature, preferably the pressure resistance of the autoclave or the like so that the polymerizable vinyl monomer and the polyalkoxysiloxane oligomer do not volatilize. Polymerization is carried out in a sealed state or under pressure using a polymerization facility.

After the polymerization, the polyalkoxysiloxane oligomer is condensed.
Examples of the condensation method of the polyalkoxysiloxane oligomer include dehydration condensation using an acid catalyst or a base catalyst. Examples of the acid catalyst and base catalyst include inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid, organic acids such as citric acid, ascorbic acid, isoascorbic acid and phenolic compounds, inorganic acids such as ammonia, sodium hydroxide, potassium hydroxide and ammonium nitrate. Bases and organic bases such as amine compounds and amide compounds can be used. When the production container is made of steel or stainless steel, it is preferable to use basic sodium hydroxide, ammonia or the like from the viewpoint of corrosion or the like. The addition amount of the catalyst is preferably 0.01 to 30 parts by weight with respect to 100 parts by weight of the polyalkoxysiloxane oligomer. More preferably, it is 1 to 15 parts by weight.

  After the condensation, if necessary, the suspension stabilizer is decomposed with hydrochloric acid, etc., and the silica-coated polymer particles are separated as a hydrous cake by a method such as suction filtration, centrifugal dehydration, centrifugal separation, and pressure dehydration. The obtained water-containing cake is washed with water and dried to obtain the desired composite particles.

  According to the method for producing composite particles, since the method is not a method in which silica particles are coated on the polymer particles by applying a high shearing force, the polymer having no Tg (glass transition point) lower than 80 ° C. Even these particles can be easily coated. Examples of the polymer having a Tg lower than 80 ° C. include polyethyl acrylate, poly (n-butyl acrylate), poly (isobutyl acrylate), poly (lauryl acrylate), poly (stearyl acrylate), poly (2-ethylhexyl acrylate), and poly (methacrylic acid). Examples include ethyl, poly (n-butyl methacrylate), poly (isobutyl methacrylate), poly (lauryl methacrylate), poly (stearyl methacrylate), and poly (2-ethylhexyl methacrylate).

(3) (Combination of various components)
Finally, composite particles prepared as described above, a solvent, a binder resin, and a pigment or the like are further blended as necessary, and mixed so that the composite particles are sufficiently dispersed to form a coating composition.

The coating composition of the present embodiment is configured as described above and manufactured as described above. Next, a coated material in which the coating composition is applied to various substrates will be described.
The coated product of the present embodiment is configured by coating the coating composition as described above on various substrates. The optical member is constituted by applying the coating composition as described above to various transparent substrates.
Examples of the substrate include metals (iron, aluminum, zinc, etc.), wood, plastic, glass, slate, mortar, stone, concrete and the like.
Specific examples include constituent members of automobiles and home appliances, transparent members such as light guide plates, building materials, miscellaneous goods, paper, and building wall materials.
The transparent substrate is preferably made of glass or plastic, for example, quartz glass, soda glass, polycarbonate, polymethyl methacrylate, polyvinyl chloride, polyester, cellulose acetate butyrate, polyolefin, polystyrene, fluororesin, epoxy resin, Examples thereof include those made of polyacrylate, silicone, polyethylene terephthalate, cycloolefin polymer, polyimide and the like.
These base materials preferably have heat resistance, curl resistance, solvent resistance and the like.

  The shape of the substrate, particularly the transparent substrate, is preferably a sheet. Such a sheet-like substrate usually has a thickness of preferably about 10 to 3000 μm, and the transparent substrate constituting the optical sheet as the optical member preferably has a thickness of 10 to 300 μm.

As a method for applying the coating composition to a substrate, particularly a transparent substrate, a known coating method can be selected. For example, reverse roll coating method, die coating method, comma coater method, spray coating method, gravure coating method, rod coating In addition to coating methods such as coating, brush coating, roller coating, spray coating, cationic electrodeposition coating, electrostatic coating, and the like can be employed.
The thickness of the coating film is preferably 1 to 500 μm, more preferably 1 to 200 μm in a dry state in which the solvent is completely volatilized. Particularly in an optical sheet, 1 to 100 μm is preferable.

  In the optical sheet as the optical member of the present invention, the coating composition may be applied to one surface of a sheet-like transparent substrate, or may be applied to both surfaces. Also good. Further, a plurality of coating films formed by applying the coating composition may be formed. Furthermore, a hard coat layer may be laminated on the surface of the coating film for preventing scratches and improving weather resistance.

Examples of the present invention will be described below.
In this example, measurements of haze, total light transmittance, specular reflectance, etc. were performed by the following methods.

(Measurement of haze, total light transmittance, specular reflectance)
The haze and total light transmittance of the coated product were measured with a haze meter (based on “NDH-2000” JIS K7105 manufactured by Nippon Denshoku Co., Ltd.).
Further, using VGS-300A and VGS-SENSOR (manufactured by Nippon Denshoku Industries Co., Ltd.), the specular reflectance at an incident light of 60 ° was measured with respect to the coating film surface of the coated material in accordance with JIS Z 8741. . The number of measurements was 5 times, and the average value was taken as the specular reflectance in this specification.

(Measurement of particle diameter)
The particle diameter was measured by the Coulter counter method.
The Coulter counter method is a method of measuring the particle diameter by an electric resistance method called the Coulter principle.
In detail, this method is described in detail by placing an electrode on both sides of the aperture (pore) of the aperture tube in the electrolyte, passing an electric current, suspending the particles to be measured in the electrolyte, and using a manometer from inside the aperture tube. When the electrolyte is sucked and passes through the aperture, the electrolyte corresponding to the particle volume is replaced, and resistance is generated between both electrodes, but this resistance change is proportional to the volume of the particle passing through the aperture. This is a method of detecting and calculating the volume average particle diameter of the particle diameter.
Specifically, according to REFERENCE MANUAL FOR THE COULTER MULTISIZER (1987) published by Coulter Electoronics Limited, calibration was performed using an aperture having a diameter of 100 μm. More specifically, as a particle diameter measuring device, a device composed of Coulter Multisizer II and Sampling Stand IIA (manufactured by Beckman Coulter) was used, and 0.1 g of particles in 10 ml of 0.1% nonionic surfactant solution. Pre-dispersed using a touch mixer and ultrasonic waves, and added to a beaker containing 300 ml of ISOTON II (manufactured by Beckman Coulter, Inc .: electrolyte for measurement) attached to the sampling stand II with a dropper while gently stirring. Then, the concentration meter on the main body screen was prepared to be around 10%, and the volume average particle diameter of 100,000 particles was measured.

(Method for confirming the coating state of composite particles)
Whether the polymer particles are exposed by a method of visually observing the composite particles with a microscope (used lens: 600 times) using a sodium lamp as a light source by dropping an aqueous dispersion of the composite particles on a glass slide. I confirmed it.

(Evaluation of redispersibility)
The prepared coating composition is filled in 40 ml of a 50 ml sample tube with a lid, and centrifuged at 3000 rpm for 10 minutes using a centrifuge to completely separate the liquid part and the solid content. It was set sideways on a shaker (manufactured by Taiyo Kagaku Kogyo Co., Ltd.) and vibrated for 10 minutes under vibration conditions of 60 times / min.
Then, the state after vibration was confirmed by visual observation, and the case where the particle lump was lost was evaluated as ◯, and the case where the particle lump remained was evaluated as x.

(Measurement method of aperture ratio)
First, 1 g of the composite particles was taken into a 50 ml magnetic crucible, and this was fired at 500 ° C. for 2 hours using an electric furnace (manufactured by ISUZU). The silica composite particles shown in FIG. Particles having only a silica portion (hereinafter referred to as silica particles) were obtained.
Next, the silica particles were gently taken out from the inside of the magnetic crucible with a spatula, and a photograph was taken with a scanning electron microscope (manufactured by JEOL Ltd .: JSM-820-A).
Furthermore, from the photographed photograph, arbitrary 50 pieces having an opening portion of silica particles on the top are selected, and each of them is manually measured by using a trace measurement of an image analysis apparatus (made by OMRON: Image-Ana LITE). The contour of the silica particle and the contour of the opening portion were designated, and the projected area (S2) and the area (S1) of the opening portion of the silica particle were measured as illustrated in FIG.
From the measured areas, the aperture ratios of the individual silica particles were determined by the following formula, and the average value was shown in the examples.
Opening ratio = area of the opening of silica particles (S1) ÷ projected area of silica particles (S2)

(Measurement of h / D of silica particles)
As shown in FIG. 2, the value of h / D when the diameter of the silica particle is D and the height of the silica particle is h was measured by the following method.
In the same manner as the aperture ratio measurement method, a scanning electron micrograph of silica particles is taken, and 50 particles whose silica particle opening surface is perpendicular to the imaging surface are selected from the photographed images. did. The value of D and h of each particle was measured with the image analysis apparatus, and h / D was calculated. In this specification, h / D means an average value of 50 h / Ds.

Production Example 1
To 200 g of water, 5 g of magnesium pyrophosphate by metathesis method is mixed as a suspension stabilizer, put into a 500 ml separable flask, 0.04 g of sodium lauryl sulfate as a surfactant, and sodium nitrite as a polymerization inhibitor. 0.02 g was dissolved in the dispersion medium.
Separately, as a polymerizable vinyl monomer, 56 g of methyl methacrylate and 14 g of ethylene glycol dimethacrylate, and as a polyalkoxysiloxane oligomer, MKC silicate MS57 (manufactured by Mitsubishi Chemical Corporation: average molecular weight 1300 to 1500, in the above structural formula, R is methyl, n The monomer composition was prepared by uniformly mixing 30 g of 15 to 18) and 0.25 g of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator.
This monomer composition is added to the dispersion medium in the separable flask and stirred for about 10 seconds at 8000 rpm with a homomixer (trade name: ULTRA TURRAX T-25, manufactured by IKA) to finely disperse the monomer composition. It was. Next, a stirring blade, a thermometer and a reflux condenser were attached to the separable flask, and after replacing with nitrogen, the flask was placed in a constant temperature water bath (water bath) at 60 ° C. Then, the inside of the separable flask is continuously stirred at a stirring speed of 200 rpm, and the polymerizable vinyl system is obtained by performing suspension polymerization for 10 hours after the temperature of the dispersion medium to which the monomer composition in the separable flask is added reaches 60 ° C. The monomer was polymerized. Next, 2 g of sodium hydroxide was added to cause dehydration condensation of the polyalkoxysiloxane oligomer.

Next, the separable flask is taken out from the constant temperature water bath, the reaction liquid in the separable flask is cooled to room temperature while stirring the separable flask, and hydrochloric acid is added until the pH of the slurry becomes about 2 to obtain a suspension stabilizer. The suspension stabilizer was removed by suction filtration with a Buchner funnel using filter paper and washed with 1.2 L of ion exchange water, and dried to obtain composite particles (flat particle diameter 15 μm). . In the obtained composite particles, a part of the surface of the polymer particles was exposed.
Table 1 shows the aperture ratio and h / D of the composite particles.

Production Example 2
Composite particles (average particle diameter of 6 μm) were obtained in the same manner as in Production Example 1 except that methyl methacrylate was changed to styrene and ethylene glycol dimethacrylate was changed to divinylbenzene. In the obtained composite particles, a part of the surface of the polymer particles was exposed.
Table 1 shows the aperture ratio and h / D of the composite particles.

Production Example 3
The composite particles were prepared in the same manner as in Production Example 1 except that MKC silicate MS58B15 (manufactured by Mitsubishi Chemical Co., Ltd .: average molecular weight 1600 to 1800) was used as the polyalkoxysiloxane oligomer, and the stirring conditions of the homomixer were 10000 rpm for about 10 seconds. An average particle diameter of 5 μm) was obtained. In the obtained composite particles, a part of the surface of the polymer particles was exposed.
Table 1 shows the aperture ratio and h / D of the composite particles.

Production Example 4
Composite particles were prepared in the same manner as in Production Example 1 except that the amount of magnesium pyrophosphate was 7.5 g, the amount of sodium lauryl sulfate as a surfactant was 0.06 g, and the stirring condition of the homomixer was 10000 rpm for 60 seconds. (Average particle diameter 3 μm) was obtained. In the obtained composite particle, a part of the polymer particle was exposed.
Table 1 shows the aperture ratio and h / D of the composite particles.

Production Example 5
Composite particles (average particle diameter of 6 μm) were obtained in the same manner as in Production Example 2 except that 56 g of styrene in Production Example 2 was changed to 28 g of styrene and 28 g of methyl methacrylate. In the obtained composite particle, a part of the polymer particle was exposed.
Table 1 shows the aperture ratio and h / D of the composite particles.

Production Example 6
Composite particles (average particle diameter 5.8 μm) were obtained in the same manner as in Production Example 1 except that 56 g of methyl methacrylate and 14 g of ethylene glycol as polymerizable vinyl monomers were changed to 70 g of methyl methacrylate.
Table 1 shows the aperture ratio and h / D of the composite particles.

Production Example 7
MKC silicate MS57 (manufactured by Mitsubishi Chemical Co., Ltd .: average molecular weight 1300 to 1500, R in the above structural formula is methyl, average n is 15 to 18) as polyalkoxysiloxane oligomer, MKC silicate MS51 (manufactured by Mitsubishi Chemical Corporation: average molecular weight) Composite particles (average particle diameter of 6.4 μm) were obtained in the same manner as in Production Example 1 except that the structural formula was changed to 500 to 700 and R in the structural formula was methyl and the average of n was 5 to 10).
Table 1 shows the aperture ratio and h / D of the composite particles.

Production Example 8
MKC silicate MS57 (manufactured by Mitsubishi Chemical Corporation: average molecular weight 1300-1500, R in the structural formula is methyl, n is an average of 15-18) as a polyalkoxysiloxane oligomer, MKC silicate MS58B15 (manufactured by Mitsubishi Chemical Corporation: average molecular weight) Composite particles (average particle diameter of 17.1 μm) were obtained in the same manner as in Production Example 1 except that 1600 to 1800 and R in the structural formula was changed to butyl and the average of n was changed to 11 to 13).
Table 1 shows the aperture ratio and h / D of the composite particles.

Production Example 9
Composite particles (average particle diameter of 19.5 μm) were obtained in the same manner as in Production Example 1 except that 56 g of methyl methacrylate and 14 g of ethylene glycol as polymerizable vinyl monomers were changed to 70 g of n-butyl acrylate.
Table 1 shows the aperture ratio and h / D of the composite particles.

Comparative production example 1
A polymerization vessel equipped with a stirrer and a thermometer was charged with 500 g of deionized water in which 0.05 g of sodium lauryl sulfate was dissolved, and 50 g of tricalcium phosphate was added and dispersed. A mixed liquid prepared by dissolving 0.5 g of benzoyl peroxide and 0.5 g of azobisisobutyronitrile in 85 g of styrene, which is a polymerizable vinyl monomer, and 15 g of divinylbenzene, was prepared in advance. T. The liquid was dispersed with a K homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to adjust the droplets to about 6 μm. Next, the inside of the polymerization vessel was heated to 65 ° C. and subjected to suspension polymerization while stirring, and then cooled. The suspension was filtered, washed and dried to obtain true spherical polymer particles (average particle diameter 6 μm).

Comparative production example 2
Spherical polymer particles (average particle diameter of 15 μm) in the same manner as in Comparative Production Example 1 except that styrene is methyl methacrylate, divinylbenzene is ethylene glycol dimethacrylate, and the droplet diameter is about 15 μm. Got.

Comparative production example 3
(Production of toluene solution of polymer)
In a 300 ml four-necked flask equipped with a stirrer, a thermometer and a condenser tube, 144.5 g of tetramethoxysilane, 23.6 g of γ-methacryloxypropyltrimethoxysilane, 19 g of water, 30 g of methanol and Amberlyst 15 (Rohm and -5 g of a cation exchange resin manufactured by Hearth Japan Co., Ltd. was added and stirred at 65 ° C. for 2 hours for reaction. After the reaction mixture is cooled to room temperature, a distillation column is attached instead of the cooling pipe, and a cooling pipe and an outlet are provided therein, and the temperature is increased to 80 ° C. over 2 hours at normal pressure until the methanol does not flow out. The reaction was allowed to proceed further. After cooling to room temperature again, Amberlyst 15 was filtered to obtain a polymerizable polysiloxane having a number average molecular weight of 1800.
Next, in a 1 liter flask equipped with a stirrer, a dripping port, a thermometer, a cooling pipe and a nitrogen gas inlet, 200 g of toluene as an organic solvent was introduced, nitrogen gas was introduced, and the flask internal temperature was increased to 110 ° C. while stirring. Heated. Next, a solution obtained by mixing 20 g of the polymerizable polysiloxane obtained above, 80 g of methyl methacrylate, 10 g of 2-ethylhexyl acrylate, 60 g of styrene, 30 g of butyl acrylate, and 6 g of 2,2′-azobisisobutyronitrile was added from the dropping port. It was dripped over 2 hours. After the dropwise addition, stirring was continued for 1 hour at the same temperature, and then 0.4 g of 1,1′-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane was added twice every 30 minutes. Copolymerization was performed by heating for 2 hours to obtain a toluene solution of a polymer in which a polymer having a number average molecular weight of 12000 was dissolved in toluene. The solid content in the obtained solution was 49.5% by weight.
(Manufacture of dispersion)
496 g of butyl acetate and 124 g of methanol were placed in a 1 liter four-necked flask equipped with a stirrer, two dripping ports (dropping ports 1 and 2) and a thermometer, and the internal temperature was adjusted to 20 ° C. Next, 10 g of the toluene solution of the polymer obtained above and 100 g of tetramethoxysilane (solution A) were mixed from the dropping port 1 with stirring of the inside of the flask and 30 g of water, 30 g of 25% aqueous ammonia and 60 g of methanol. The liquid (solution B) was added dropwise from the dropping port 2 over 1 hour. After the dropping, stirring was continued for 2 hours until the same temperature. Next, 37 g of a toluene solution of the polymer obtained above and 37 g of butyl acetate were dropped from the dropping port 1 over 1 hour. After dropping, stirring was continued for 2 hours at the same temperature. Further, the temperature inside the flask was raised to 100 ° C. under a pressure of 110 mmHg, and ammonia, methanol, toluene and butyl acetate were distilled off until the solid content concentration became 30% by weight. A dispersion dispersed in was obtained. The average particle diameter (volume diameter) of the obtained fine particles was diluted with ion-exchanged water until the solid content was around 1% by weight, and a laser diffraction / diffusion-type particle size distribution measuring device (trade name “LS230”, It was 0.18 μm (180 nm) as a result of measurement by Coulter Co.).
(Manufacture of composite particles)
In a flask equipped with a stirrer, an inert gas introduction tube, a reflux condenser and a thermometer, 900 g of deionized water in which 0.5 g of polyvinyl alcohol (PVA-205, manufactured by Kuraray Co., Ltd.) was dissolved was charged. Next, 75 g of methyl methacrylate, 19 g of ethylene glycol dimethacrylate, 20 g of the dispersion obtained above and 1 g of azobisisobutyronitrile were charged into a flask. K. A uniform suspension was prepared by stirring at 3000 rpm for 5 minutes with a homogenizer (manufactured by Tokushu Kika Kogyo Co., Ltd.).
Next, the mixture was heated to 75 ° C. while blowing nitrogen gas, and stirred at this temperature for 5 hours to carry out the polymerization reaction, and then cooled, filtered, washed and dried to obtain composite particles (average particle diameter of 12 μm). ) The composite particles had a structure in which silica particles were dispersed in polymer particles derived from a polymerizable vinyl monomer.

Comparative production example 4
Polymer particles (average particle diameter of 5 μm) were obtained in the same manner as in Comparative Production Example 2, except that the particle diameter of the droplets was adjusted to about 5 μm.

Comparative Production Example 5
In the monomer composition of Comparative Production Example 2, 5 g of lipophilic smectite (trade name “SAN”, manufactured by Coop Chemical Co., Ltd.) was uniformly dispersed, and the particle diameter of the droplet was adjusted to about 6 μm (the stirring condition of the homomixer was Smectite-dispersed composite particles (average particle diameter 6 μm) were obtained by the same method as in Comparative Production Example 2 except for 10,000 seconds at 10,000 rpm.

Example 1
To a binder solution in which 100 parts by weight of an acrylic resin (trade name “BR106”, manufactured by Mitsubishi Rayon Co., Ltd.) as a binder resin is dissolved in 300 parts by weight of a solvent (180 parts by weight of toluene, 90 parts by weight of ethyl acetate, 30 parts by weight of butyl acetate). Then, 100 parts by weight of the composite particles produced in Production Example 1 were blended and dispersed uniformly to prepare a coating composition.
This coating composition was coated on a polyethylene terephthalate film as a transparent substrate having a thickness of 100 μm using a 75 μm applicator and dried to produce a light diffusion sheet.
The haze and total light transmittance of the surface of this light diffusion sheet were measured by the above methods. The results are shown in Table 2 below.

Example 2
A light diffusion sheet was produced in the same manner as in Example 1 except that the composite particles obtained in Production Example 2 were used instead of the composite particles in Example 1 and the addition amount was 20 parts by weight. And the haze and total light transmittance of the surface of the obtained light-diffusion sheet were measured. The results are shown in Table 2 below.

Example 3
A light diffusing sheet was produced in the same manner as in Example 1 except that the composite particles obtained in Production Example 5 were used instead of the composite particles in Example 1 and the addition amount was 70 parts by weight. And the haze and total light transmittance of the surface of the obtained light-diffusion sheet were measured. The results are shown in Table 2 below.

Example 4
A light diffusion sheet was produced in the same manner as in Example 1 except that the addition amount of the composite particles was changed to 150 parts by weight. And the haze and total light transmittance of the surface of the obtained light-diffusion sheet were measured. The results are shown in Table 2 below.

Comparative Example 1
A light diffusing sheet was obtained in the same manner as in Example 1, except that 3 g of the polymer particles obtained in Comparative Production Example 1 were not used in the composite particles of Example 1 with respect to 300 g of methyl methacrylate resin. It was. And the haze and total light transmittance of the surface of the obtained light-diffusion sheet were measured. The results are shown in Table 2 below.

Comparative Example 2
A light diffusing sheet was obtained in the same manner as in Example 1 except that the polymer particles obtained in Comparative Production Example 2 were used instead of the composite particles in Example 1. And the haze and total light transmittance of the surface of the obtained light-diffusion sheet were measured. The results are shown in Table 2 below.

Comparative Example 3
A light diffusing sheet was obtained in the same manner as in Example 1 except that the composite particles obtained in Comparative Production Example 3 were used instead of the composite particles in Example 1. And the haze and total light transmittance of the surface of the obtained light-diffusion sheet were measured. The results are shown in Table 2 below.

Comparative Example 4
A light diffusing sheet was obtained in the same manner as in Example 1 except that the composite particles obtained in Comparative Production Example 5 were used in place of the composite particles in Example 1. And the haze and total light transmittance of the surface of the obtained light-diffusion sheet were measured. The results are shown in Table 2 below.

As can be seen from Comparative Examples 1, 2, 3, and 4 in Table 2, generally, increasing the haze decreases the total light transmittance, and increasing the total light transmittance decreases the haze (particularly Comparative Example 1). It is. That is, usually, an increase in haze means a decrease in total light transmittance, and an increase in total light transmittance means a decrease in haze.
However, the optical sheets of Examples 1, 2, 3, and 4 have both improved haze and total light transmittance as compared to Comparative Examples 2, 3, and 4, as compared with Comparative Examples 2, 3, and 4. .
As is clear from this, an optical sheet (optical member) obtained by using composite particles provided with a silica coating so that a part of the polymer particles is exposed as particles to be blended in the coating composition. ) Can be excellent in both light diffusibility (haze) and total light transmittance. Therefore, it is recognized that the light diffusion sheet is suitable for a light diffusion sheet interposed between a prism sheet and a light guide plate in a liquid crystal display device, for example.

Example 5
A binder solution in which 100 parts by weight of a polyester resin (trade name “Byron 200”, manufactured by Toyobo Co., Ltd.) as a binder resin is dissolved in 300 parts by weight of a solvent (180 parts by weight of toluene, 90 parts by weight of ethyl acetate, 30 parts by weight of butyl acetate). Then, 10 parts by weight of the composite particles produced in Production Example 3 were blended and dispersed uniformly to prepare a coating composition.
This coating composition was coated on a polyethylene terephthalate film, which was a transparent substrate having a thickness of 100 μm, using an applicator having a thickness of 20 μm and dried to obtain an antiglare sheet. And the haze, total light transmittance, and specular reflectance of the surface of the obtained anti-glare sheet were measured. The results are shown in Table 3 below.

Example 6
An antiglare sheet was obtained in the same manner as in Example 5 except that the composite particles obtained in Production Example 4 were used instead of the composite particles used in Example 5 and the blending amount was 5 parts by weight. It was. And the haze, total light transmittance, and specular reflectance of the surface of the obtained anti-glare sheet were measured. The results are shown in Table 3 below.

Example 7
An antiglare sheet was obtained in the same manner as in Example 5 except that the composite particles obtained in Production Example 5 were used instead of the composite particles used in Example 5 and the blending amount was 20 parts by weight. It was. And the haze, total light transmittance, and specular reflectance of the surface of the obtained anti-glare sheet were measured. The results are shown in Table 3 below.

Comparative Example 5
An antiglare sheet was obtained in the same manner as in Example 5 except that the polymer particles obtained in Comparative Production Example 4 were used in place of the composite particles used in Example 5. And the haze, total light transmittance, and specular reflectance of the surface of the obtained anti-glare sheet were measured. The results are shown in Table 3 below.

Comparative Example 6
An antiglare sheet was obtained in the same manner as in Example 5 except that the composite particles obtained in Comparative Production Example 3 were used in place of the composite particles used in Example 5. And the haze, total light transmittance, and specular reflectance of the surface of the obtained anti-glare sheet were measured. The results are shown in Table 3 below.

Comparative Example 7
An antiglare sheet was obtained in the same manner as in Example 5 except that the composite particles obtained in Comparative Production Example 5 were used in place of the composite particles used in Example 5. And the haze, total light transmittance, and specular reflectance of the surface of the obtained anti-glare sheet were measured. The results are shown in Table 3 below.

As is clear from Table 3, the optical sheets of Examples 5, 6, and 7 have both improved haze and total light transmittance as compared with the comparative example. Moreover, the specular reflectance is greatly reduced.
As is clear from this, an optical sheet (optical member) obtained by using composite particles provided with a silica coating so that a part of the polymer particles is exposed as particles to be blended in the coating composition. ) Is excellent in both light diffusibility (haze) and total light transmittance, and can be very low in specular reflectance. Therefore, it is recognized that it is suitable for an anti-glare sheet, for example, an anti-glare sheet arranged on the most front side in a liquid crystal display device.

Example 8
It is obtained in Production Example 1 to 400 parts by weight (a binder resin content of about 30 parts by weight) of an aqueous binder solution (trade name “Vylonal MD1200” manufactured by Toyobo Co., Ltd.) using a polyester resin as a binder resin and water and alcohol as solvents. 50 parts by weight of the composite resin was blended and dispersed uniformly to prepare a coating composition. This coating composition was applied onto a black and white masking paper (BYK-Garder) using a 75 μm applicator and dried to prepare a coating. And the specular reflectance of the surface of the obtained coating material was measured.
In addition, the redispersibility of the prepared coating composition was evaluated. The results are shown in Table 4 below.

Example 9
A coating composition was prepared in the same manner as in Example 8, except that the composite particles obtained in Production Example 2 were used instead of the composite particles used in Example 8, and the blending amount was 10 parts by weight. Was prepared. Further, in the same manner as in Example 8, the specular reflectance was measured and the redispersibility was evaluated. The results are shown in Table 4 below.

Example 10
A coating composition was prepared in the same manner as in Example 8, except that the composite particles obtained in Production Example 5 were used instead of the composite particles used in Example 8, and the blending amount was 100 parts by weight. Was prepared. Further, in the same manner as in Example 8, the specular reflectance was measured and the redispersibility was evaluated. The results are shown in Table 4 below.

Example 11
A coating composition was prepared in the same manner as in Example 8, except that the composite particles obtained in Production Example 6 were used instead of the composite particles used in Example 8. Further, in the same manner as in Example 8, the specular reflectance was measured and the redispersibility was evaluated. The results are shown in Table 4 below.

Example 12
A coating composition was prepared in the same manner as in Example 8, except that the composite particles obtained in Production Example 7 were used instead of the composite particles used in Example 8. Further, in the same manner as in Example 8, the specular reflectance was measured and the redispersibility was evaluated. The results are shown in Table 4 below.

Example 13
A coating composition was prepared in the same manner as in Example 8, except that the composite particles obtained in Production Example 8 were used instead of the composite particles used in Example 8. Further, in the same manner as in Example 8, the specular reflectance was measured and the redispersibility was evaluated. The results are shown in Table 4 below.

Example 14
A coating composition was prepared in the same manner as in Example 8, except that the composite particles obtained in Production Example 9 were used instead of the composite particles used in Example 8. Further, in the same manner as in Example 8, the specular reflectance was measured and the redispersibility was evaluated. The results are shown in Table 4 below.

Comparative Example 8
Instead of the composite particles used in Example 8, the polymer particles obtained in Comparative Production Example 2 were used, and the coating amount was the same as in Example 8 except that the blending amount was 10 parts by weight. A composition was prepared. Further, in the same manner as in Example 8, the specular reflectance was measured and the redispersibility was evaluated. The results are shown in Table 4 below.

Comparative Example 9
Instead of the composite particles used in Example 8, the composite particles obtained in Comparative Production Example 3 were used, and the composition for coating was the same as in Example 8 except that the blending amount was 10 parts by weight. A product was prepared. Further, in the same manner as in Example 8, the specular reflectance was measured and the redispersibility was evaluated. The results are shown in Table 4 below.

Comparative Example 10
A coating composition was prepared in the same manner as in Example 8 except that the composite particles were not blended. Further, as in Example 8, the specular reflectance was measured. The results are shown in Table 4 below.

Comparative Example 11
A coating composition was obtained in the same manner as in Example 8, except that the composite particles obtained in Comparative Production Example 5 were used instead of the composite particles used in Example 8, and the blending amount was 20 parts by weight. A product was prepared. Further, in the same manner as in Example 8, the specular reflectance was measured and the redispersibility was evaluated. The results are shown in Table 4 below.

  As is apparent from Table 4, it can be seen that the coating composition of the present invention has good redispersibility, that is, dispersion stability even in an aqueous system.

  The coated product of the present invention is effective in fields where matting and antiglare are required because the specular reflectance of the coating film is suppressed. In particular, since the optical member of the present invention can be excellent in light transmittance and light diffusibility, it is required to have high light diffusibility and light transmittance such as a lighting fixture cover, a light guide plate, and a projection television screen. Effective in the field.

The schematic sectional drawing which shows the composite particle of this embodiment. The schematic sectional drawing of the silica particle obtained by baking the composite particle of this embodiment. Schematic for demonstrating the measuring method of an aperture ratio.

Explanation of symbols

2 ... Composite particles 2a ... Polymer particles 2b ... Silica coating

Claims (7)

A composition for coating in which composite particles are blended in a binder solution containing a binder resin and a solvent,
The composite particles include polymer particles derived from a polymerizable vinyl monomer, and a silica coating provided so that at least a part of the surface is exposed on the surface of the polymer particles, and the silica coating is a polyalkoxysiloxane. A coating composition comprising an oligomer condensate.   The silica coating has an aperture ratio of 0.1 to 1, and the weight so that the height h of the silica coating and the diameter D of the composite particles have a relationship of 0.5 ≦ h / D <1. The coating composition according to claim 1, wherein the polymer particles are coated by exposing the surface of the coalesced particles.   The coating composition according to claim 1 or 2, wherein the amount of the composite particles is 1-150 parts by weight with respect to 100 parts by weight of the binder resin.   A coated product obtained by coating the coating composition according to any one of claims 1 to 3 on a substrate.   An optical member obtained by applying the coating composition according to claim 1 to a transparent substrate.   The optical member according to claim 5, wherein the amount of the composite particles is 20 to 120 parts by weight with respect to 100 parts by weight of the binder resin.   A liquid crystal display using the optical member according to claim 6.

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