WO2021210257A1

WO2021210257A1 - Composite particle and method for producing same

Info

Publication number: WO2021210257A1
Application number: PCT/JP2021/005393
Authority: WO
Inventors: 井口　良範
Original assignee: 信越化学工業株式会社
Priority date: 2020-04-15
Filing date: 2021-02-15
Publication date: 2021-10-21
Also published as: TW202203884A; JP2021169421A

Abstract

The present invention is a composite particle in which organic resin particles are adhered to the surface of an inorganic particle, the composite particle being characterized in that the organic resin particles are anchored to the inorganic particle using silica as a binder. This serves to provide a hydrophilic composite particle in which organic resin particles are adhered to the surface of an inorganic particle, and to provide a method for producing the composite particle.

Description

Composite particles and their manufacturing methods

The present invention relates to composite particles, specifically composite particles formed by adhering organic resin particles to the surface of inorganic particles, and a method for producing the same.

Makeup cosmetics such as foundations are intended to hide morphological problems such as wrinkles, pores, and roughness of the skin, and color problems such as skin spots and freckles, and to make the skin look smooth and beautiful in recent years. In, the emphasis is on a natural, non-artificial finish (feeling of bare skin). In addition, the natural finish of cosmetics is evaluated when there is no unnatural luster, the cosmetic film has excellent uniformity of adhesion, and it has high transparency.

Conventionally, many new materials and new technologies have been proposed in order to obtain a natural finish while following the effects of the above makeup cosmetics.

In particular, the present inventor has proposed composite particles in which silicone elastomer particles having light diffusivity are adhered to the surface of arbitrary nuclear particles using a silicone resin as a binder (Patent Document 1), and cosmetics containing the composite particles. The agent can visually express the effect of improving skin morphology troubles, has a soft and moist feeling as a smoothness peculiar to silicone elastomer, and has good spreadability, softness, stickiness, and mixing condition, and skin morphology correction. The effect can be given.

As binders for silicone resins in these composite particles, Patent Document 1 states that _{polymers consisting of [CH 3} SiO _3/2 ] units, so-called polymethylsilsesquioxane, [CH ₃ SiO _3/2 ] units and [CH 3 SiO 3/2] units. Specific examples of a polymer consisting of H ₂ NC ₃ H ₆ SiO _3/2 ] units, and a polymer consisting of [CH ₃ SiO _3/2 ] units and [(CH ₃ ) ₂ SiO _{2/2] units are shown.} There is. These silicone resins are water repellent, and when the composite particles are coated with the silicone resin, the composite particles become water repellent. It is necessary to use a surfactant to add this to an aqueous cosmetic product, but since the surfactant has irritation to the skin, its use in cosmetics may be avoided.

Japanese Unexamined Patent Publication No. 2011-1332.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide composite particles having hydrophilicity and having organic resin particles adhered to the surface of inorganic particles, and a method for producing the same.

In order to achieve the above object, in the present invention, the composite particles are composite particles in which organic resin particles are attached to the surface of the inorganic particles, and the organic resin particles are fixed to the inorganic particles using silica as a binder. I will provide a.

If it is such a thing, it can be made into a composite particle formed by adhering organic resin particles to the surface of inorganic particles showing hydrophilicity.

Further, it is preferable that the inorganic particles are one or more selected from barium sulfate, talc, mica, and sericite.

With such a product, when blended in cosmetics, a more remarkable soft focus effect, that is, an effect of making wrinkles and the like inconspicuous by light scattering can be obtained.

Further, the amount of the organic resin particles is preferably in the range of 0.5 to 100 parts by mass with respect to 100 parts by mass of the inorganic particles.

If it is such a product, when it is added to cosmetics, it will give a better feeling of use such as more remarkable soft focus effect, silky feeling, smoothness, stretchability, moist feeling, softness, etc., and composite particles. There is no risk of agglomeration.

Further, in the present invention, tetraalkoxysilane is added to the above-mentioned method for producing composite particles, which is a mixture of an aqueous dispersion in which the inorganic particles and the organic resin particles are dispersed and an alkaline substance. Provided is a method for producing composite particles to be hydrolyzed and condensed.

The composite particle of the present invention can be produced by such a method.

Further, it is preferable to further add a cationic surfactant to the mixed solution.

By doing so, the organic resin particles are uniformly adhered to the surface of the inorganic particles, and the adhesion by silica is sufficient.

At this time, the blending amount of the cationic surfactant is preferably in the range of 0.01 to 2 parts by mass with respect to 100 parts by mass of water in the mixed solution.

By doing so, the organic resin particles adhere uniformly to the surface of the inorganic particles, and the adhesion by silica becomes more sufficient.

As described above, since the composite particles of the present invention have hydrophilicity, they can be blended in water-based cosmetics without necessarily blending a dispersant such as a surfactant or a water-soluble polymer. It is expected that cosmetics can be provided with good spreadability, softness, adhesion, mixing condition, and excellent skin morphology correction effect.

It is an electron micrograph of the composite particle obtained in Example 1. FIG.

As described above, there has been a demand for the development of composite particles having organic resin particles adhered to the surface of inorganic particles showing hydrophilicity and a method for producing the same.

As a result of diligent studies to achieve the above object, the present inventor has found that the above problems can be solved by forming composite particles formed by adhering organic resin particles to the surface of inorganic particles using silica as a binder. This is what led to the present invention.

That is, the present invention is a composite particle in which organic resin particles are attached to the surface of the inorganic particles, and the organic resin particles are fixed to the inorganic particles using silica as a binder.

Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[Composite particles]
The composite particles of the present invention are particles formed by adhering organic resin particles to the surface of inorganic particles (inorganic powder) using silica as a binder.

<Inorganic particles>
The inorganic particles used in the present invention are particles that form the core of composite particles. As the inorganic particles, one type alone or two or more types can be used as appropriate, and powders substantially usable in cosmetics and particles having a particle size in the entire range can be applied. Further, as long as the geometrical aspect is that usually used for cosmetics, it may have any shape such as spherical, polyhedral, spindle-shaped, needle-shaped, plate-shaped, and any of non-porous and porous. It may be.

The average particle size is preferably in the range of 0.5 to 50 μm, more preferably 1 to 30 μm. When the particle size is 0.5 μm or more, a feeling of use such as smoothness and smoothness and the effect of imparting extensibility can be sufficiently obtained, and when the particle size is 50 μm or less, the feeling of roughness can be reduced. The average particle size is appropriately selected from a microscope method, a light scattering method, a laser diffraction method, a liquid phase sedimentation method, an electric resistance method, and the like according to each shape.

Inorganic particles include titanium oxide, titanium mica, zirconium oxide, zinc oxide, cerium oxide, magnesium oxide, barium sulfate, calcium sulfate, magnesium sulfate, calcium carbonate, magnesium carbonate, talc, talc, mica (mica), kaolin, Serisite, white mica, synthetic mica, gold mica, red mica, black mica, lithia mica, silicic acid, silicon dioxide, hydrous silicon dioxide, aluminum silicate, magnesium silicate, magnesium silicate, calcium silicate, silicic acid Barium, strontium silicate, metal tungrate, hydroxyapatite, vermiculite, hygilite, bentonite, montmorillonite, hectrite, zeolite, ceramics, calcium diphosphate, alumina, aluminum hydroxide, boron titanate, boron titanate, glass, etc. Particles can be mentioned.

Further, inorganic pigments are mentioned, and specific examples thereof include inorganic red pigments such as iron oxide, iron hydroxide and iron titanate; inorganic brown pigments such as γ-iron oxide; yellow iron oxide and yellow clay. Inorganic yellow pigments; Inorganic black pigments such as black iron oxide and carbon black; Inorganic purple pigments such as manganese violet and cobalt violet; Inorganic green pigments such as chromium hydroxide, chromium oxide, cobalt oxide and cobalt titanate; Inorganic blue pigments such as dark blue and ultramarine; colored pigments such as tar-based pigments raked and natural pigments raked; titanium oxide-coated mica, titanium oxide-coated mica, bismuth oxychloride, titanium oxide-coated oxychloride Pearl pigments such as bismuth, titanium oxide-coated talc, fish scale foil, and titanium oxide-coated colored mica; metal powder pigments such as aluminum powder, copper powder, and stainless powder can be mentioned.

Barium sulfate, talc, mica, and sericite are preferable when a more remarkable soft focus effect is desired.

Inorganic particles may be surface-treated with metal soap, silane, silicone, silicone resin, fluorine compound, amino acid, iron oxide, titanium oxide, iron oxide or aluminum hydroxide.

<Organic resin particles>
The organic resin particles used in the present invention are particles adhering to the surface of the inorganic particles that form the core of the composite particles. As the organic resin particles, one type alone or two or more types can be used as appropriate, and powders substantially usable for cosmetics and particles having a particle size in the entire range can be applied. Further, as long as the geometrical aspect is that usually used for cosmetics, it may have any shape such as spherical, polyhedral, spindle-shaped, needle-shaped, plate-shaped, and any of non-porous and porous. It may be.

The particle size of the organic resin particles is preferably smaller than that of the inorganic particles. If the size is smaller than that of the inorganic particles, which are the nuclear powders, the characteristics such as the smoothness of the powder, the feeling of use such as smoothness, the extensibility, and the adhesiveness are sufficiently exhibited. The average particle size is preferably in the range of 0.05 to 5 μm, more preferably 0.1 to 1 μm.

Organic resin particles include polyamide, polyacrylic acid / acrylic acid ester, polyester, polyethylene, polypropylene, polystyrene, styrene / acrylic acid copolymer, divinylbenzene / styrene copolymer, polyurethane, vinyl resin, urea resin, and melamine resin. , Benzoguanamine, polymethylbenzoguanamine, tetrafluoroethylene, polymethylmethacrylate such as polymethylmethacrylate, cellulose, silk, nylon, phenol resin, epoxy resin, polycarbonate, polybutadiene rubber, acrylic rubber, urethane rubber, silicone rubber, fluororubber, etc. Particles can be mentioned.

In the present invention, the density of the organic resin particles adhering to the surface of the inorganic particles is not particularly limited. That is, the organic resin particles may be sparsely adhered to the surface of the inorganic particles, or the surface of the inorganic particles may be coated and adhered without gaps.

The amount of the organic resin particles is not particularly limited when the effect of adding to the cosmetic is exhibited, but the more remarkable soft focus effect, silky feeling, smoothness, stretchability, moist feeling, softness, etc. are good. When a good feeling of use is desired, it is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and further preferably 2 parts by mass or more with respect to 100 parts by mass of the inorganic particles. Further, from the viewpoint of obtaining more sufficient low cohesiveness and soft focus effect, it is preferably 100 parts by mass or less, more preferably 70 parts by mass or less, and further preferably 50 parts by mass or less with respect to 100 parts by mass of the inorganic particles. ..

<Silica>
The silica used in the present invention is a binder of inorganic particles and organic resin particles. By using silica as a binder to form composite particles formed by adhering organic resin particles to the surface of inorganic particles, the organic resin particles are fixed to the surface of the inorganic particles and are less likely to fall off from the surface of the inorganic particles, resulting in a better usability. Can be given.

The shape of silica may be film-like or granular, and may be partially or wholly attached to the surface of inorganic particles and / or the surface of organic resin particles. Silica has a _{structure composed of 2} units of SiO, and the production method thereof is not particularly limited, but silica is preferably obtained by a hydrolysis / condensation reaction of tetraalkoxysilane as in the production method described later.

The amount of silica is not particularly limited, but in order to fix the organic resin particles to the surface of the inorganic particles, it is preferably 10 parts by mass or more, more preferably 20 parts by mass or more with respect to 100 parts by mass of the organic resin particles. More preferably, it is 30 parts by mass or more. Further, from the viewpoint of obtaining a more sufficient soft focus effect, it is preferably 500 parts by mass or less, more preferably 300 parts by mass or less, and further preferably 200 parts by mass or less with respect to 100 parts by mass of the organic resin particles.

The state in which the organic resin particles are attached to the surface of the inorganic particles can be confirmed with an electron microscope.

The composite particles of the present invention are particles formed by adhering organic resin particles to the surface of inorganic particles using silica as a binder and have hydrophilicity. It is also possible to treat the particle surface with a silylating agent, silicone oil, waxes, paraffins, an organic fluorine compound, a surfactant, or the like in order to improve the dispersibility of the particles.

[Manufacturing method of composite particles]
The composite particles formed by adhering the organic resin particles to the surface of the inorganic particles using the silica of the present invention as a binder are composed of an aqueous dispersion (mixed water dispersion) in which the inorganic particles and the organic resin particles are dispersed and an alkaline substance. It can be obtained by adding tetraalkoxysilane to the blended mixed solution and hydrolyzing / condensing the mixture.

In the method for producing composite particles of the present invention, the above-mentioned inorganic particles and organic resin particles can be used.

The inorganic particles are preferably 3 to 150 parts by mass, more preferably 5 to 50 parts by mass, with respect to 100 parts by mass of the water to be blended. When the amount is 3 parts by mass or more, the production efficiency is high, and when the amount is 150 parts by mass or less, the kinematic viscosity of the aqueous dispersion does not become too high, and organic resin particles are easily attached. The amount of the organic resin particles may be an amount that adheres to the surface of the inorganic particles.

A surfactant and a water-soluble polymer may be blended in order to disperse the inorganic particles and / or the organic resin particles in water.

The surfactant is not particularly limited, but a nonionic surfactant, a cationic surfactant, and / or an amphoteric surfactant are preferable.

Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyethylene glycol fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, and poly. Oxyethylene sorbit fatty acid ester, glycerin fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyglycerin fatty acid ester, propylene glycol fatty acid ester, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene hydrogenated castor oil fatty acid ester, poly Examples thereof include oxyethylene alkylamine, polyoxyethylene fatty acid amide, polyoxyethylene modified organopolysiloxane, and polyoxyethylene polyoxypropylene modified organopolysiloxane.

Examples of the cationic surfactant include alkyltrimethylammonium salt, dialkyldimethylammonium salt, polyoxyethylene alkyldimethylammonium salt, dipolyoxyethylene alkylmethylammonium salt, tripolyoxyethylene alkylammonium salt, alkylbenzyldimethylammonium salt, and alkylpyri. Examples thereof include a didium salt, a monoalkylamine salt, and a monoalkylamidoamine salt.

Examples of the amphoteric surfactant include alkyldimethylamine oxide, alkyldimethylcarboxybetaine, alkylamidepropyldimethylcarboxybetaine, alkylhydroxysulfobetaine, and alkylcarboxymethylhydroxyethylimidazolinium betaine.

The water-soluble polymer is not particularly limited, but a nonionic water-soluble polymer and / or a cationic water-soluble polymer is preferable.

Examples of the nonionic water-soluble polymer include polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, polymethyl vinyl ether, polyisopropylacrylamide, methyl cellulose, hydroxypropyl methyl cellulose, starch, guagam, and kitansan gum.

Examples of the cationic water-soluble polymer include a polymer of dimethyldialylammonium chloride, a polymer of vinylimidazoline, a polymer of methylvinylimidazolium chloride, a polymer of ethyltrimethylammonium chloride acrylate, and a polymer of ethyltrimethylammonium chloride methacrylate. Polymer, acrylamide propyltrimethylammonium chloride polymer, methacrylicamidopropyltrimethylammonium chloride polymer, epichlorohydrin / dimethylamine polymer, ethyleneimine polymer, quaternary product of ethyleneimine polymer, allylamine hydrochloride Examples thereof include polymers, polylysine, cationic starch, cationized cellulose, chitosan, and derivatives thereof obtained by copolymerizing a monomer having a nonionic group or an anionic group with them.

As the inorganic particles and / or the organic resin particles, those prepared in advance as an aqueous dispersion or an aqueous dispersion synthesized in water may be used.

In the method for producing composite particles of the present invention, an alkaline substance is further used. The alkaline substance is a catalyst for the hydrolysis / condensation reaction of tetraalkoxysilane.

The amount of the alkaline substance to be blended is preferably at least an amount in which the pH of the mixed solution of the alkaline substance and the aqueous dispersion in which the inorganic particles and the organic resin particles are dispersed is 9.0 to 12.0, preferably 9.5 to 12.0. An amount of 11.5 is more preferable. When an alkaline substance having a pH of 9.0 to 12.0 is added, the hydrolysis / condensation reaction of tetraalkoxysilane proceeds and the organic resin particles are sufficiently adhered to the surface of the inorganic particles.

The alkaline substance is not particularly limited, and for example, alkali metal hydroxides such as potassium hydroxide, sodium hydroxide and lithium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide and barium hydroxide; potassium carbonate and carbon dioxide. Alkali metal carbonates such as sodium; ammonia; tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide; or monomethylamine, monoethylamine, monopropylamine, monobutylamine, monopentylamine, dimethylamine, diethylamine , Trimethylamine, triethanolamine, ethylenediamine and other amines can be used. Among them, ammonia is most suitable because it can be easily removed from the powder of the obtained composite particles by volatilization. As the ammonia, a commercially available aqueous solution of ammonia can be used.

In the present invention, it is preferable that the cationic surfactant is added to the mixture of the aqueous dispersion in which the inorganic particles and the organic resin particles are dispersed and the alkaline substance. By doing so, the organic resin particles are uniformly adhered to the surface of the inorganic particles, and the adhesion by silica is sufficient.

Examples of the cationic surfactant include those mentioned above, but an alkyltrimethylammonium salt is preferable.

The amount of the cationic surfactant is preferably 0.01 to 2 parts by mass with respect to 100 parts by mass of water in a mixed solution containing an aqueous dispersion in which inorganic particles and organic resin particles are dispersed and an alkaline substance. , More preferably in the range of 0.02 to 1 part by mass. When the blending amount is 0.01 part by mass to 2 parts by mass, the organic resin particles are uniformly adhered to the surface of the inorganic particles, and the adhesion by silica is sufficient.

The method of blending the cationic surfactant into the mixed solution is not particularly limited, but for example, a mixed solution containing an aqueous dispersion in which inorganic particles and organic resin particles are dispersed and an alkaline substance will be described later. It may be added before the addition of the tetraalkoxysilane, or it may be added at the same time as the addition of the tetraalkoxysilane, which will be described later. When used as a dispersant for inorganic powder and / or organic resin particles, it is already blended, but it may be additionally added if necessary.

In the method for producing composite particles of the present invention, tetraalkoxysilane is added to a mixed solution in which an aqueous dispersion in which inorganic particles and organic resin particles are dispersed and an alkaline substance are mixed. Tetraalkoxysilane is hydrolyzed and condensed by the catalytic action of the above-mentioned alkaline substance to become silica. After the addition of tetraalkoxysilane, the silica produced by the hydrolysis / condensation reaction of tetraalkoxysilane is formed on the surface of the inorganic particles and / or on the surface of the organic resin particles, and at the same time, the organic resin particles are adsorbed on the surface of the inorganic particles. As a result, the organic resin particles are fixed to the surface of the inorganic particles with silica.

The tetraalkoxysilane is represented by ^{Si (OR 6} ) _4. ^{R 6} in the formula is an alkyl group. As the alkyl group, an alkyl group having 1 to 6 carbon atoms is preferable. Specific examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group and the like, but from the viewpoint of reactivity, a methyl group and an ethyl group are more preferable. That is, tetramethoxysilane and tetraethoxysilane are more preferable, and tetramethoxysilane is even more preferable. As the tetraalkoxysilane, one in which a part or all of the alkoxy group is hydrolyzed may be used. Further, a partially condensed product may be used.

The amount of tetraalkoxysilane added is not particularly limited, but the amount of silica after the hydrolysis / condensation reaction may be set to be the amount relative to the amount of the above-mentioned organic resin particles.

Tetraalkoxysilane is added while stirring a mixed solution containing an aqueous dispersion (mixed water dispersion) in which inorganic particles and organic resin particles are dispersed and an alkaline substance. The tetraalkoxysilane may be added by gradually dropping it, or it may be added in a form dissolved in water or dispersed in water, and a solution containing a water-soluble organic solvent such as alcohol is added. You may.

From the viewpoint of preventing aggregation of the inorganic particles, the stirring may be loose using paddle blades, propeller blades, swept blades, anchor-shaped blades, etc., but the inorganic particles, organic resin particles, and tetraalkoxysilane are mixed. Stirring strength is required to disperse in the liquid.

The temperature at which tetraalkoxysilane is added to the mixed solution is preferably 0 to 60 ° C, more preferably 0 to 39 ° C. If this temperature is 0 ° C. or higher, the mixed solution is unlikely to solidify, and if it is 60 ° C. or lower, the obtained particles are unlikely to coagulate.

A water-soluble organic solvent such as alcohol may be added to the mixed solution for the purpose of uniformly adhering the organic resin particles to the surface of the inorganic particles. When the particles are surface-treated with a silylating agent, the finished composite particles may be treated, or the silylating agent may be added and then treated after adding tetraalkoxysilane to the mixed solution. Examples of the silylating agent include trimethylmethoxysilane, trimethylsilanol, hexamethyldisilazane, methyltrimethoxysilane, and phenyltrimethoxysilane.

After the addition of tetraalkoxysilane is completed, it is preferable to continue stirring for a while until the hydrolysis / condensation reaction is completed. It may be heated at 40-100 ° C. to accelerate the reaction, or an alkaline substance may be added. After that, if necessary, an acidic substance may be added to neutralize the substance.

Remove water after hydrolysis / condensation reaction. Moisture can be removed, for example, by heating the mixed solution after the reaction under normal pressure or reduced pressure. Specifically, a method of allowing the mixed solution to stand under heating to remove water, mixing. Examples thereof include a method of removing water while stirring and flowing the liquid under heating, a method of spraying and dispersing the mixed liquid in a hot air stream such as a spray dryer, and a method of using a fluidized heat medium. As a pretreatment for this operation, the mixed solution may be concentrated by a method such as heat dehydration, filtration separation such as pressure filtration, centrifugation, decantation, etc., and if necessary, the mixed solution may be concentrated with water, alcohol, or the like. You may wash it.

If the powder obtained by removing water from the mixed solution after the reaction is agglomerated, it may be crushed or classified with a crusher such as a jet mill, a ball mill, or a hammer mill.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the example, the kinematic viscosity is a value measured using a capillary viscometer at 25 ° C., and "%" indicating the concentration and the content rate indicates "mass%".

[Manufacturing Example 1]
(Manufacturing of aqueous dispersion of silicone rubber particles)
349 g of methylvinylpolysiloxane having a kinematic viscosity of 61 mm ² / s represented by the following formula (1) and 51 g of methylhydrogen polysiloxane having a kinematic viscosity of 30 mm ² / s represented by the following formula (2) (vinyl group). A glass beaker having a capacity of 1 liter (a blending amount in which 1.2 hydrosilyl groups were added to each) was charged and mixed and dissolved using a homomixer. When 26 g of polyoxyethylene tridecyl ether (trade name: Neugen TDS-100, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and 40 g of water were added and stirred using a homomixer, the viscosity was increased to a state where stirring was not possible. The thickener was kneaded with a homodisper for 15 minutes. Then, 532 g of water was added and mixed using a homomixer to obtain a uniform white emulsion. This emulsion is transferred to a glass flask having a capacity of 1 liter equipped with a stirrer using an anchor-type stirring blade, the temperature is adjusted to 20 to 25 ° C., and then an isododecane solution (platinum content) of a platinum-vinyl group-containing disiloxane complex under stirring. A mixed solution of 1 g (0.5%) and 1 g of polyoxyethylene tridecyl ether (trade name: Neugen TDS-100, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added, and the mixture was stirred at the same temperature for 24 hours, and made of silicone rubber. An aqueous dispersion of particles was obtained.

The volume average particle size of the obtained silicone rubber particles was measured using a "laser diffraction / scattering type particle size distribution measuring device LA-960" (manufactured by HORIBA, Ltd.) and found to be 360 nm.

Next, the methylvinylpolysiloxane having a kinematic viscosity of 61 mm ² / s represented by the above formula (1), the methylhydrogen polysiloxane having a kinematic viscosity of 30 mm ² / s represented by the above formula (2), and platinum. -An isododecane solution of a vinyl group-containing disiloxane complex (platinum content 0.5%) is mixed at the above blending ratio, poured into an aluminum chalet so as to have a thickness of 10 mm, left at 25 ° C. for 6 hours, and then further 50 ° C. It was heated for 1 hour in a constant temperature bath. The obtained cured product was a non-sticky rubber elastic body, and the hardness was 48 when measured with a durometer A hardness tester.

[Manufacturing Example 2]
(Manufacturing of aqueous dispersion of acrylic particles)
Acrylic particles (trade name: MP-2200, manufactured by Soken Kagaku Co., Ltd., shape = spherical, average particle size = 350 nm) 50 g, polyoxyethylene tridecyl ether (trade name: Neugen TDS-) in a glass beaker with a capacity of 1 liter. 100, 3.5 g of Dai-ichi Kogyo Seiyaku Co., Ltd., and 447 g of water were charged and mixed using a homomixer. The mixture was passed through a high pressure homogenizer at a pressure of 40 MPa to obtain an aqueous dispersion of acrylic particles.

[Example 1]
Using a glass flask with a capacity of 2 liters equipped with a stirrer with an anchor-shaped stirrer, mica particles (trade name: Y-5000, made of Kakuhachi fish scale foil, shape = plate, average particle size = 14 μm) A mixed water dispersion in which 90 g, 22 g of the silicone rubber particle aqueous dispersion obtained in Production Example 1 (the amount of silicone rubber particles is 9.8 parts by mass with respect to 100 parts by mass of mica particles), and 805 g of water are mixed. Was charged with 1.6 g of 2.8% ammonia water. The pH of the liquid at this time was 10.8. After adjusting the temperature to 5 to 10 ° C., 24 g of tetramethoxysilane (the amount of silica after hydrolysis / condensation reaction is 108 parts by mass with respect to 100 parts by mass of silicone rubber particles) and 30% lauryltrimethylammonium chloride aqueous solution (commodity). Name: Cationic BB, manufactured by Nichiyu Co., Ltd., and 58 g of an aqueous solution diluted 10-fold with water (amount of lauryltrimethylammonium chloride in an amount of 0.2 parts by mass with respect to 100 parts by mass of water) was added dropwise over 20 minutes. During this period, the liquid temperature was maintained at 5 to 10 ° C., and stirring was further carried out for 1 hour. Then, the mixture was heated to 75 to 80 ° C. and stirred for 1 hour while maintaining the temperature to complete the hydrolysis / condensation reaction of tetramethoxysilane. The obtained suspension was dehydrated using a pressure filter. The dehydrated product was transferred to a glass flask having a capacity of 2 liters equipped with a stirring device using an anchor-shaped stirring blade, 1,000 g of water was added, the mixture was stirred for 30 minutes, and then dehydrated using a pressure filter. This operation was repeated twice. The obtained dehydrated product was dried in a hot air flow dryer at a temperature of 105 ° C., and the dried product was crushed with a jet mill to obtain particles.

When the obtained particles were observed with an electron microscope, spherical particles having a size of about 350 nm were uniformly adhered to the surface of the plate-shaped particles, and the composite particles formed by adhering silicone rubber particles to the surface of the mica particles. It was confirmed that it was. An electron micrograph is shown in FIG.

Next, when 5 g of the obtained particles were added to a 100 mL beaker containing 80 g of water and stirred with a glass rod, all the particles were dispersed in water, and it was confirmed that the particles were hydrophilic. Further, when the particles were allowed to stand for 24 hours and the ups and downs of the particles were observed, all the particles were settled. Silicone rubber particles float because their specific gravity is smaller than that of water. From this result, it is judged that the silicone rubber particles have not fallen off from the surface of the mica particles, and silica acts as a binder to fix the silicone rubber particles to the surface of the mica particles. It was suggested that

[Example 2]
90 g of mica particles of Example 1 were talc particles (trade name: JA-69R, manufactured by Asada Flour Milling Co., Ltd., shape = plate shape, average particle size = 10 μm), except that the particles were the same as in Example 1. Got

When the obtained particles were observed with an electron microscope, spherical particles having a size of about 350 nm were uniformly adhered to the surface of the plate-shaped particles, and the composite particles formed by adhering silicone rubber particles to the surface of the talc particles. It was confirmed that it was.

Next, when 5 g of the obtained particles were added to a 100 mL beaker containing 80 g of water and stirred with a glass rod, all the particles were dispersed in water, and it was confirmed that the particles were hydrophilic. Further, when the particles were allowed to stand for 24 hours and the ups and downs of the particles were observed, all the particles were settled. Silicone rubber particles float because their specific gravity is smaller than that of water. From this result, it is judged that the silicone rubber particles have not fallen off from the surface of the talc particles, and silica acts as a binder to fix the silicone rubber particles to the surface of the talc particles. It was suggested that

[Example 3]
Same as in Example 1 except that 90 g of mica particles of Example 1 was 90 g of sericite particles (trade name: Sanshin Mica FSE, manufactured by Sanshin Mining Co., Ltd., shape = plate shape, average particle size = 10 μm). Obtained particles.

When the obtained particles were observed with an electron microscope, spherical particles having a size of about 350 nm were uniformly adhered to the surface of the plate-shaped particles, and composite particles formed by adhering silicone rubber particles to the surface of the sericite particles. It was confirmed that

Next, when 5 g of the obtained particles were added to a 100 mL beaker containing 80 g of water and stirred with a glass rod, all the particles were dispersed in water, and it was confirmed that the particles were hydrophilic. Further, when the particles were allowed to stand for 24 hours and the ups and downs of the particles were observed, all the particles were settled. Silicone rubber particles float because their specific gravity is smaller than that of water. From this result, it is judged that the silicone rubber particles have not fallen off from the surface of the sericite particles, silica acts as a binder, and the silicone rubber particles are placed on the surface of the sericite particles. It was suggested that they were stuck.

[Example 4]
Barium sulfate particles (trade name: plate-shaped barium sulfate HL, manufactured by Sakai Chemical Industry Co., Ltd., shape = plate-shaped, average particle size = Mixed water dispersion in which 90 g of 15 μm), 87 g of the aqueous dispersion of acrylic particles obtained in Production Example 2 (amount of 9.7 parts by mass of acrylic particles with respect to 100 parts by mass of barium sulfate particles) and 740 g of water are mixed. 1.6 g of 2.8% ammonia water was charged into the liquid. The pH of the liquid at this time was 10.7. After adjusting the temperature to 5 to 10 ° C, 24 g of tetramethoxysilane (amount of silica after hydrolysis / condensation reaction becomes 109 parts by mass with respect to 100 parts by mass of acrylic particles) and a 30% lauryltrimethylammonium chloride aqueous solution (trade name). : 58 g of an aqueous solution obtained by diluting cation BB, manufactured by Nichiyu Co., Ltd. with water 10 times (amount of lauryltrimethylammonium chloride in an amount of 0.2 parts by mass with respect to 100 parts by mass of water) was added dropwise over 20 minutes. During this period, the liquid temperature was maintained at 5 to 10 ° C., and stirring was further carried out for 1 hour. Then, the mixture was heated to 75 to 80 ° C. and stirred for 1 hour while maintaining the temperature to complete the hydrolysis / condensation reaction of tetramethoxysilane. The obtained suspension was dehydrated using a pressure filter. The dehydrated product was transferred to a glass flask having a capacity of 2 liters equipped with a stirring device using an anchor-shaped stirring blade, 1,000 g of water was added, the mixture was stirred for 30 minutes, and then dehydrated using a pressure filter. This operation was repeated twice. The obtained dehydrated product was dried in a hot air flow dryer at a temperature of 105 ° C., and the dried product was crushed with a jet mill to obtain particles.

When the obtained particles were observed with an electron microscope, spherical particles having a size of about 350 nm were uniformly adhered to the surface of the plate-shaped particles, and the composite particles formed by adhering acrylic particles to the surface of barium sulfate particles. It was confirmed that it was.

Next, when 5 g of the obtained particles were added to a 100 mL beaker containing 80 g of water and stirred with a glass rod, all the particles were dispersed in water, and it was confirmed that the particles were hydrophilic. Further, when the particles were allowed to stand for 24 hours and the ups and downs of the particles were observed, all the particles were settled. Acrylic particles float because their specific gravity is smaller than that of water. From this result, it is judged that the acrylic particles have not fallen off from the surface of the mica particles, and silica acts as a binder to fix the acrylic particles to the surface of the barium sulfate particles. It has been suggested.

Furthermore, when the obtained composite particles were subjected to element mapping with a fluorescent X-ray analyzer, silicon and oxygen were detected in the entire particles. From this, it was determined that the composite particles were entirely coated with silica, and the silica served as a binder, and the acrylic particles were fixed to the surface of the barium sulfate particles.

[Comparative Example 1]
Using a glass flask with a capacity of 2 liters equipped with a stirrer with an anchor-shaped stirrer, mica particles (trade name: Y-5000, made of Kakuhachi fish scale foil, shape = plate, average particle size = 14 μm) A mixed water dispersion in which 90 g, 22 g of the silicone rubber particle aqueous dispersion obtained in Production Example 1 (the amount of silicone rubber particles is 9.8 parts by mass with respect to 100 parts by mass of mica particles), and 817 g of water are mixed. Was charged with 20 g of 28% ammonia water. The pH of the liquid at this time was 11.4. After adjusting the temperature to 5 to 10 ° C., 19 g of methyltrimethoxysilane (amount of polymethylsilsesquioxane after hydrolysis / condensation reaction becomes 106 parts by mass with respect to 100 parts by mass of silicone rubber particles) and 30% lauryl. 32 g of an aqueous solution of trimethylammonium chloride aqueous solution (trade name: cation BB, manufactured by Nichiyu Co., Ltd.) diluted 10-fold with water (amount of lauryltrimethylammonium chloride in 0.1 parts by mass with respect to 100 parts by mass of water) Was added dropwise over 20 minutes, the liquid temperature during this period was maintained at 5 to 10 ° C., and stirring was further carried out for 1 hour. Then, the mixture was heated to 75 to 80 ° C. and stirred for 1 hour while maintaining the temperature to complete the hydrolysis / condensation reaction of methyltrimethoxysilane. The obtained suspension was dehydrated using a pressure filter. The dehydrated product was transferred to a glass flask having a capacity of 2 liters equipped with a stirring device using an anchor-shaped stirring blade, 1,000 g of water was added, the mixture was stirred for 30 minutes, and then dehydrated using a pressure filter. This operation was repeated twice. The obtained dehydrated product was dried in a hot air flow dryer at a temperature of 105 ° C., and the dried product was crushed with a jet mill to obtain particles.

When the obtained particles were observed with an electron microscope, spherical particles having a size of about 350 nm were uniformly adhered to the surface of the plate-shaped particles, and the composite particles formed by adhering silicone rubber particles to the surface of the mica particles. It was confirmed that it was.

Next, when 5 g of the obtained particles were added to a 100 mL beaker containing 80 g of water and stirred with a glass rod, all the particles were not dispersed in water and were in a floating state, confirming that they were water-repellent particles. Was done.
Add 5 g of the obtained particles to a 100 mL beaker containing 80 g of 0.5% by mass dissolved water of polyoxyethylene lauryl ether (trade name: Emargen 109P, manufactured by Kao Corporation), and stir with a glass rod to mix the particles. Distributed. After that, the particles were allowed to stand for 24 hours, and when the ups and downs of the particles were observed, all the particles had settled. Silicone rubber particles float because their specific gravity is smaller than that of polyoxyethylene lauryl ether dissolved water. From this result, it is judged that the silicone rubber particles have not fallen off from the surface of the mica particles, and the silicone resin serves as a binder to the surface of the mica particles. It was suggested that silicone rubber particles were fixed to the surface.

From the results of Examples 1 to 4, it was clarified that the composite particles of the present invention using silica as a binder would be hydrophilic composite particles. On the other hand, in Comparative Example 1, the composite particles did not show hydrophilicity because a silicone resin having a methyl group was used as the binder instead of silica.

The present invention is not limited to the above embodiment. The above-described embodiment is an example, and any object having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect and effect is the present invention. Is included in the technical scope of.

Claims

Composite particles in which organic resin particles are attached to the surface of inorganic particles.
A composite particle characterized in that the organic resin particles are adhered to the inorganic particles using silica as a binder.
The composite particle according to claim 1, wherein the inorganic particle is at least one selected from barium sulfate, talc, mica, and sericite.
The composite particle according to claim 1 or 2, wherein the amount of the organic resin particles is in the range of 0.5 to 100 parts by mass with respect to 100 parts by mass of the inorganic particles.
The method for producing composite particles according to any one of claims 1 to 3.
A method for producing composite particles, which comprises adding tetraalkoxysilane to a mixed solution of an aqueous dispersion in which the inorganic particles and the organic resin particles are dispersed and an alkaline substance, and hydrolyzing and condensing the particles. ..
The method for producing composite particles according to claim 4, wherein a cationic surfactant is further added to the mixed solution.
The method for producing composite particles according to claim 5, wherein the blending amount of the cationic surfactant is in the range of 0.01 to 2 parts by mass with respect to 100 parts by mass of water in the mixed solution. ..