Composite particles, method for producing composite particles, and cosmetic

Abstract

The present invention is a composite particle characterized by comprising particles of cellulose or a cellulose derivative, and silica adhered to the surface of the particles, the silica being a polymer of tetraalkoxysilane, the tetraalkoxysilane being 1-60 parts by mass per 100 parts by mass of the particles. As a result, fine particles having excellent biodegradability and tactile sensation are provided.

Description

Technical Field

[0001] The present invention relates to cellulose-silica composite particles, alkoxy-modified composite particles, a method for producing these composite particles, and cosmetics. Background Art

[0002] In the past, various polymer microparticles based on uses have been proposed. For example, as microparticles contained in cosmetics, their purposes are diverse. The purposes of containing microparticles in cosmetics are: improving the spreadability of cosmetics, giving a change to the touch, imparting an anti-wrinkle effect, and improving the smoothness of foundations and the like.

[0003] Particularly, microparticles with high sphericity have excellent touch, and a light scattering (soft focus) effect can be obtained depending on their physical properties or shape. Also, when such microparticles are used in foundations and the like, by filling the unevenness of the skin to make it smooth and scattering light in all directions, it is possible to expect a (soft focus) effect that makes wrinkles and the like less noticeable.

[0004] For such purposes and effects of cosmetics, the microparticles incorporated in cosmetics need to be microparticles with a narrow particle size distribution and high sphericity. As such microparticles, microparticles composed of synthetic polymers such as polyamides such as nylon 12, polymethyl methacrylate (PMMA), and polystyrene (PS) have been proposed.

[0005] However, the specific gravity of the microparticles composed of these synthetic polymers is as light as 1 or less, and the particle diameter is also extremely small, so they are likely to float on water and there are cases where they cannot be removed in wastewater treatment facilities, and sometimes they directly flow into rivers or further flow into the ocean through rivers. Therefore, there is also a problem that the ocean and the like are contaminated with the microparticles composed of these synthetic polymers.

[0006] Furthermore, since the microparticles composed of these synthetic polymers also have the property of adsorbing trace chemical contaminants in the environment, there is a concern that various effects such as adverse effects on the human body may be caused by plankton or fish swallowing the microparticles adsorbed with the chemical contaminants.

[0007] Due to such concerns, attempts have been made to use biodegradable particles instead of the microparticles of synthetic polymers used in various applications.

[0008] As a representative biodegradable resin, there is cellulose. The advantage of cellulose is that it does not compete with food or feed and can be obtained from natural raw materials such as wood or cotton. Therefore, it is desired to develop microparticles containing cellulose.

[0009] In addition, synthetic resin powder based on silicone as the main raw material forms a uniform coating film on the surface of the skin or hair, and is used in various cosmetics such as hair cosmetics, color cosmetics, sunscreen, etc. as an important component for imparting moisture or smoothness, and for providing water resistance or water repellency. For example, Patent Document 1 discloses silicone fine particles having a soft touch, no cohesiveness, and excellent dispersibility. Therefore, it is suitable for blending as a cosmetic, but there is a need to develop a better resin powder.

[0010] Patent Document 2 discloses blending particles obtained by surface-treating cellulose acetate particles with a lipophilic imparting agent containing a silicone-based component as a cosmetic composition. However, as this method, the lipophilic imparting agent is attached to the cellulose acetate particles by a wet treatment method, and an organic solvent such as n-hexane needs to be used. Therefore, there is a need to develop an environmentally friendly aqueous composite particle.

[0011] Prior Art Documents

[0012] Patent Documents

[0013] Patent Document 1: Japanese Patent Laid-Open No. 07-196815

[0014] Patent Document 2: International Publication No. 2020 / 188698 Summary of the Invention

[0015] (I) Technical Problem to be Solved

[0016] In view of the above circumstances, the present invention aims to provide fine particles having excellent biodegradability and touch.

[0017] (II) Technical Solution

[0018] To solve the above technical problem, the present invention provides a composite particle comprising particles of cellulose or a cellulose derivative, and silica attached to the surface of the particles, wherein the silica is a polymer of tetraalkoxysilane, and the tetraalkoxysilane is 1 to 60 parts by mass with respect to 100 parts by mass of the particles.

[0019] For such a composite particle, by coating biodegradable cellulose particles with silica that imparts slidability, water resistance, etc., a composite particle is formed, which becomes a composite particle having excellent biodegradability and touch.

[0020] In addition, it is preferable that the particles of cellulose or a cellulose derivative have a volume average particle diameter of 1 to 300 μm.

[0021] If the volume average particle diameter is set to such a value, the touch of the composite particle of the present invention is more excellent and suitable for cosmetics.

[0022] In addition, it is preferable that the tetraalkoxysilane is tetramethoxysilane.

[0023] If such a tetraalkoxysilane is used, the hydrolysis and condensation reactions of the tetraalkoxysilane can be more surely carried out to obtain composite particles in a state where silica is attached to the cellulose particles.

[0024] In addition, it is preferable that the coating film of the composite particles of the present invention has a coefficient of static friction of less than 0.50.

[0025] If such composite particles are used, a cosmetic having excellent smoothness can be obtained.

[0026] In addition, it is preferable that the above-mentioned composite particles have been alkoxylated.

[0027] If such composite particles are used, waterproof particles can be produced.

[0028] In addition, the present invention provides a composite particle, characterized in that it comprises particles of cellulose or a cellulose derivative, and silica attached to the surface of the particles, and 50% or more of the specific surface area of the particles is coated with silica.

[0029] For such composite particles, by coating biodegradable cellulose particles with silica that imparts slidability, waterproofness, etc., composite particles are produced, which become composite particles having excellent biodegradability and touch.

[0030] In addition, it is preferable that the particles of cellulose or a cellulose derivative have a volume average particle diameter of 1 to 300 μm.

[0031] If the volume average particle diameter is set to such a value, the touch of the composite particles of the present invention is more excellent and suitable for cosmetics.

[0032] In addition, it is preferable that the silica is a polymer of tetraalkoxysilane.

[0033] If such silica is used, the hydrolysis and condensation reactions of the tetraalkoxysilane can be more surely carried out to obtain composite particles in a state where silica is attached to the cellulose particles.

[0034] In addition, it is preferable that the tetraalkoxysilane is tetramethoxysilane.

[0035] If such a tetraalkoxysilane is used, the hydrolysis and condensation reactions of the tetraalkoxysilane can be more surely carried out to obtain composite particles in a state where silica is attached to the cellulose particles.

[0036] In addition, the composite particles of the present invention preferably have a coating film of the composite particles with a coefficient of static friction of less than 0.50.

[0037] If such composite particles are used, a cosmetic having excellent smoothness can be obtained.

[0038] In addition, the above composite particles are preferably alkoxylated.

[0039] If such composite particles are used, water-repellent particles can be produced.

[0040] In addition, the present invention provides a method for producing composite particles, which composite particles include particles of cellulose or a cellulose derivative and silica attached to the surface of the particles. The production method is characterized by including:

[0041] Step (1), in the presence of (A) particles of cellulose or a cellulose derivative, water, and an alkali, subject (B) tetraalkoxysilane in an amount of 1 to 60 parts by mass relative to 100 parts by mass of the (A) particles to hydrolysis and condensation reactions to form silica, and attach the silica to the surface of the (A) particles to obtain the composite particles.

[0042] Thus, the composite particles of the present invention can be produced by an aqueous reaction.

[0043] At this time, after the step (1), it may include: step (2), a step of removing water.

[0044] If so, the composite particles of the present invention can be obtained in a powder state.

[0045] In addition, the present invention provides a cosmetic containing the above composite particles.

[0046] The composite particles of the present invention can be suitably used for cosmetics.

[0047] At this time, it is preferred to contain the composite particles in an amount of 1 to 50% by mass based on the total amount of the cosmetic.

[0048] If the blending amount is set like this, the cosmetic of the present invention can sufficiently obtain the effects of the composite particles of the present invention.

[0049] (III) Advantageous Effects

[0050] When the composite particles of the present invention are used by being blended in a cosmetic, the cosmetic can be made to have slidability, a soft touch, water repellency, etc. Thus, the composite particles of the present invention can be blended in various cosmetics such as hair cosmetics, makeup cosmetics, sunscreen creams, etc. And because it is biodegradable, it is environmentally friendly. Description of the Drawings

[0051] Figure 1 An electron micrograph of the surface of the composite particles obtained in Example 3.

[0052] Fig. 2(a) is a photograph (a) of the surface of the composite particles obtained in Example 3 taken with an electron microscope.

[0053] Fig. 2(b) is an image (b) obtained by superimposing the elemental mapping image of silicon and the elemental mapping image of carbon corresponding to the photograph of Fig. 2(a).

[0054] Fig. 2(c) is an image (c) corresponding to the image of Fig. 2(b) and showing only the signal of silicon.

[0055] Figure 3 An electron micrograph of the surface of the composite particles obtained in Comparative Example 4. Detailed Description of the Invention

[0056] As described above, there is a need to develop fine particles having excellent biodegradability and touch.

[0057] In order to achieve the above object, the inventors of the present application conducted intensive studies and as a result, developed a composite particle obtained by coating cellulose particles with silica, thereby completing the present invention.

[0058] That is, the present invention provides a composite particle, a method for producing the same, and a cosmetic containing the composite particle. The composite particle is characterized in that it contains particles of cellulose or a cellulose derivative and silica attached to the surface of the particles. The silica is a polymer of a tetraalkoxysilane, and the tetraalkoxysilane is 1 to 60 parts by mass relative to 100 parts by mass of the particles. Further, there are provided a composite particle obtained by alkoxylating the composite particle, a method for producing the same, and a cosmetic containing the alkoxylated composite particle.

[0059] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0060] [Composite Particle]

[0061] The present invention relates to a composite particle characterized in that it contains particles of cellulose or a cellulose derivative and silica attached to the surface of the particles. The silica is a polymer of a tetraalkoxysilane, and the tetraalkoxysilane is 1 to 60 parts by mass relative to 100 parts by mass of the particles. Hereinafter, a detailed description will be given.

[0062] (A) Particles of Cellulose or Cellulose Derivative

[0063] Particles of cellulose or cellulose derivatives (hereinafter sometimes collectively referred to as cellulose particles) are particles containing cellulose. They may also be cellulose derivative particles such as cellulose acetate or cellulose acetate propionate. In addition, the shape of the cellulose particles is not limited to spherical, and may be an amorphous shape, but spherical cellulose particles are preferred.

[0064] The volume average particle diameter of the cellulose particles is preferably 1 to 300 μm. More preferably, it is 1 to 150 μm, and still more preferably 1 to 50 μm. More specifically, volume average particle diameters such as 3 μm, 5 μm, 7 μm, 10 μm, 15 μm, 20 μm, and 45 μm can be cited. Here, the volume average particle diameter of the cellulose particles is the cumulative volume 50% particle diameter obtained from the data measured using a laser diffraction particle size distribution analyzer (for example, "SALD2100" manufactured by SHIMADZU CORPORATION).

[0065] The bulk density of the cellulose particles is preferably 0.4 to 1.0 g / cm 3 . If it is 1.0 g / cm 3 or less, a light feeling can be obtained when blended into cosmetics, and the oil absorption property also becomes good. In addition, the bulk density can be calculated by the following method: Add the sample to a container of about 200 ml, measure the weight after removing the remaining sample from the upper surface of the container, and calculate according to the following formula.

[0066] Bulk density (g / cm 3 ) = sample weight (g) / container volume (cm 3 )

[0067] As a device for measuring the bulk density, for example, Powder Tester PT-X (manufactured by Hosokawa Micron CORPORATION) can be used.

[0068] The angle of repose of the cellulose particles is preferably 60° or less. If it is 60° or less, there is no concern about giving a sticky touch, so it is preferred. In addition, the angle of repose can be obtained by the following method: Pour about 10 g of the sample through a funnel with a diameter of 6 mm to form a sample pile on the tray below, and measure the angle formed by the slope of the sample pile and the horizontal plane at this time. As a device for measuring the angle of repose, for example, Powder Tester PT-X (manufactured by Hosokawa Micron CORPORATION) can be used.

[0069] For example, a suspension in which cellulose acetate particles are dispersed in water can be prepared by suspending a cellulose acetate solution obtained by dissolving cellulose acetate in an organic solvent in water, removing the organic solvent from the suspension, and saponifying the cellulose acetate particles such that the amount of acetic acid is 0.5 ppm or less relative to the mass of cellulose, thereby producing cellulose particles or cellulose derivatives. After saponifying the cellulose acetate particles to produce cellulose particles, water can be further removed by solid-liquid separation, and the cellulose particles can be dried.

[0070] As commercially available cellulose particles, for example, BELLOCEA (registered trademark, manufactured by Daicel CORPORATION, cellulose acetate), Viscopearl (registered trademark, manufactured by Rengo Co., Ltd.), ART PEARL NC-400, and NC-800 (manufactured by Negami Chemical Industrial Co., Ltd.) can be used.

[0071] (B) Silicon dioxide

[0072] The composite particles of the present invention are formed by attaching silicon dioxide to the surface of the above-mentioned cellulose particles. The silicon dioxide is a polymer of tetraalkoxysilane. Tetraalkoxysilane is represented by the following chemical formula.

[0073] Si(OR)4

[0074] (In the formula, R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Most preferably, it is a methyl group.)

[0075] One kind of tetraalkoxysilane can be used alone, or two or more kinds can be used simultaneously.

[0076] As the above-mentioned tetraalkoxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane are preferred. Tetramethoxysilane in which R is a methyl group is particularly preferred.

[0077] In the composite particles of the present invention, the attached silicon dioxide is a polymer obtained by hydrolysis and condensation reactions of tetraalkoxysilane, and has a structure containing SiO2 units, but it may also contain alkoxy groups derived from the starting tetraalkoxysilane or silanol groups that have not undergone condensation reactions.

[0078] [Manufacturing method]

[0079] The present invention provides a method for manufacturing composite particles, which comprise particles of cellulose or a cellulose derivative and silicon dioxide attached to the surface of the particles, and the manufacturing method is characterized in that it includes:

[0080] Step (1): In the presence of particles of (A) cellulose or a cellulose derivative, water, and an alkali, (B) a tetraalkoxysilane in an amount of 1 to 60 parts by mass relative to 100 parts by mass of the (A) particles is subjected to hydrolysis and condensation reactions to form silica, and the silica is caused to adhere to the surface of the (A) particles to obtain the composite particles. It may also include, thereafter: Step (2), a step of removing water. Here, the silica is a polymer containing SiO2 units. Hereinafter, the production method of the present invention will be described in detail.

[0081] Step (1) in the production method of the present invention is to subject (B) a tetraalkoxysilane to hydrolysis and condensation reactions in the presence of (A) cellulose particles, water, and an alkali to form silica. The silica obtained by the hydrolysis and condensation reactions can be obtained in a state of adhering to the cellulose particles.

[0082] The alkali functions as a catalyst for the hydrolysis and condensation reactions of (B) a tetraalkoxysilane or as a catalyst for the condensation reaction. The alkali can be used alone or two or more kinds can be used simultaneously. In addition, the alkali can be added directly or added as an alkaline aqueous solution. Further, the alkali can be blended before adding the tetraalkoxysilane to the aqueous dispersion containing cellulose particles and water, or can be added after adding the tetraalkoxysilane.

[0083] Regarding the addition amount of the alkali, it is an amount such that the pH of the aqueous dispersion containing cellulose particles and water is preferably in the range of 9.0 to 12.0, more preferably 9.5 to 11.5. If the pH is within the above range, the hydrolysis and condensation reactions of the tetraalkoxysilane can be sufficiently carried out, and the obtained silica can be sufficiently adhered to the surface of the cellulose particles.

[0084] The alkali is not particularly limited as long as it causes the hydrolysis and condensation reactions of (B) a tetraalkoxysilane to proceed. 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; alkali metal carbonates such as potassium carbonate and sodium carbonate; ammonia; tetraalkylammonium hydroxides such as tetramethylammonium hydroxide and tetraethylammonium hydroxide; or amines such as monomethylamine, dimethylamine, diethylamine, trimethylamine, triethanolamine, and ethylenediamine can be used. Among them, ammonia is most suitable because it can be easily removed from the powder of the obtained cellulose particles by volatilization. Ammonia water available on the market can be used.

[0085] Regarding the addition amount of (B) tetraalkoxysilane, it is an amount in the range of 1 to 60 parts by mass of (B) tetraalkoxysilane relative to 100 parts by mass of (A) cellulose particles. Preferably, it is an amount in the range of 5 to 50 parts by mass, and more preferably in the range of 15 to 40 parts by mass. If the amount of (B) tetraalkoxysilane is less than 1 part by mass, the effect of silica cannot be exhibited. If it exceeds 60 parts by mass, silica that does not coat the cellulose particles or cohesive particles will be generated, resulting in a poor feel. When blended as a cosmetic, hardness or graininess will be produced.

[0086] Regarding the addition of (B) tetraalkoxysilane, it is desirable to use a conventional stirrer such as a propeller blade or a flat blade, and preferably carry out the stirring at 50 to 500 rpm.

[0087] In addition, for the purpose of controlling the adhesion of silica adhered to the surface of cellulose particles, a surfactant or a water-soluble polymer can be added to the cellulose aqueous dispersion.

[0088] The surfactant added to the aqueous dispersion is not particularly limited, and examples include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Two or more surfactants can be used. When a surfactant is added, the amount can be in the range of 0.01 part by mass to 10 parts by mass relative to 100 parts by mass of (A) cellulose particles.

[0089] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyethylene glycol fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerol fatty acid esters, polyoxyethylene glycerol fatty acid esters, polyglycerol fatty acid esters, propylene glycol fatty acid esters, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene fatty acid amides, polyoxyethylene-modified organopolysiloxanes, polyoxyethylene polyoxypropylene-modified organopolysiloxanes, etc.

[0090] Examples of anionic surfactants include alkyl sulfates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl phenyl ether sulfates, sulfate esters of fatty acid alkanolamides, alkylbenzene sulfonates, α-sulfo fatty acid esters, alkylnaphthalene sulfonates, alkyl diphenyl ether disulfosuccinates, fatty acid salts, polyoxyethylene alkyl ether carboxylates, N-acyl amino acid salts, monoalkyl phosphate salts, dialkyl phosphate salts, polyoxyethylene alkyl ether phosphate salts, etc.

[0091] Examples of the cationic surfactant include alkyltrimethylammonium salts, dialkyldimethylammonium salts, polyoxyethylene alkyldimethylammonium salts, polyoxyethylene (2) alkyldimethylammonium salts, polyoxyethylene (3) alkyldimethylammonium salts, alkylbenzyldimethylammonium salts, alkylpyridinium salts, monoalkylamine salts, monoalkylamide amine salts, and the like.

[0092] Examples of the zwitterionic surfactant include alkyldimethylamine oxides, alkyldimethylcarboxybetaines, alkylamidopropyldimethylcarboxybetaines, alkylhydroxy sulfobetaines, alkylcarboxymethylhydroxyethylimidazoline betaines, and the like.

[0093] The water-soluble polymer added to the aqueous dispersion is not particularly limited, and examples thereof include nonionic water-soluble polymers, anionic water-soluble polymers, cationic water-soluble polymers, and zwitterionic water-soluble polymers. The water-soluble polymer can be used alone or in combination of two or more. When the water-soluble polymer is added, the amount thereof can be in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the (A) cellulose particles.

[0094] Examples of the nonionic water-soluble polymer include copolymers of vinyl alcohol and vinyl acetate, polymers of acrylamide, polymers of vinylpyrrolidone, copolymers of vinylpyrrolidone and vinyl acetate, polyethylene glycol, polymers of isopropylacrylamide, polymers of methyl vinyl ether, starch, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, guar gum, xanthan gum, and the like.

[0095] Examples of the anionic water-soluble polymer compound include polymers of sodium acrylate, copolymers of sodium acrylate and sodium maleate, copolymers of sodium acrylate and acrylamide, polymers of sodium styrenesulfonate, copolymers of sodium polyisoprenesulfonate and styrene, polymers of sodium naphthalenesulfonate, carboxymethyl starch, phosphate starch, carboxymethyl cellulose, sodium alginate, gum arabic, carrageenan, sodium chondroitin sulfate, sodium hyaluronate, and the like.

[0096] Examples of the cationic water-soluble polymer include polymers of dimethyldiallylammonium chloride, polymers of vinylimidazoline, polymers of methylvinylchloroimidazolium, polymers of ethyltrimethylammonium acrylate, polymers of ethyltrimethylammonium methacrylate, polymers of acrylamidopropyltrimethylammonium chloride, polymers of methacrylamidopropyltrimethylammonium chloride, epichlorohydrin / dimethylamine polymers, polymers of ethyleneimine, quaternized products of polymers of ethyleneimine, polymers of allylamine hydrochloride, polylysine, cationic starch, cationized cellulose, chitosan, and derivatives of these components obtained by copolymerizing these components with monomers having nonionic groups or anionic groups.

[0097] Examples of zwitterionic water-soluble polymers include copolymers of ethyltrimethylammonium chloride acrylate and acrylamide, copolymers of ethyltrimethylammonium chloride methacrylate, acrylic acid and acrylamide, Hofmann degradation products of acrylamide polymers, and the like.

[0098] One embodiment of the production method of the present invention is to add (B) tetraalkoxysilane after adding an alkali to an aqueous dispersion containing (A) cellulose particles and water. In this case, the tetraalkoxysilane may be added all at once, but it is preferably added slowly over time. The reaction temperature when adding the tetraalkoxysilane is preferably in the range of 0 to 60°C, more preferably in the range of 0 to 40°C. If the temperature is within the above range, silica can be smoothly attached to the surface of the cellulose particles. Then, the hydrolysis reaction of the tetraalkoxysilane is carried out, and stirring is continued at least until the tetraalkoxysilane is completely dissolved in water. At this time, a small amount of alkali may be added to promote the hydrolysis reaction. After adding the tetraalkoxysilane, stirring is continued until the hydrolysis and condensation reactions of the tetraalkoxysilane are completed. In order to complete the hydrolysis, this reaction may be carried out at room temperature or under heating at about 40 to 100°C, and alkali may be appropriately added.

[0099] In another embodiment of the production method of the present invention, the tetraalkoxysilane may be added before adding the alkali. In this case, the tetraalkoxysilane may first be added to water. The tetraalkoxysilane may be added to water all at once or slowly over time. In addition, water may be added to the tetraalkoxysilane, or water and the tetraalkoxysilane may be added to the tank and mixed simultaneously. The temperature when adding the tetraalkoxysilane to water is not particularly limited, and for example, it may be carried out as long as it is in the range of 0 to 100°C. Then, the hydrolysis reaction of the tetraalkoxysilane is carried out, and stirring is continued at least until the tetraalkoxysilane is completely dissolved in water. At this time, a small amount of alkali may be added to promote the hydrolysis reaction.

[0100] Then, an aqueous dispersion containing cellulose particles is added to the solution obtained above, and then an alkali is added. When the alkali is added, the condensation reaction of the hydrolysis product of the tetraalkoxysilane proceeds to form silica. However, at this time, it is necessary to stop stirring or stir very slowly before silica is formed. If the reaction solution flows at a high speed when silica is formed, the silica cannot be well attached to the cellulose particles.

[0101] The temperature during the condensation reaction is preferably in the range of 0 to 60 °C, more preferably in the range of 0 to 40 °C. If the temperature is within the above range, silica can be well adhered to the cellulose particles. Until the formation of silica (silica adheres to the surface of cellulose particles), the reaction solution can be left standing or placed in a very slow stirring state. In addition, the standing time is preferably in the range of 10 minutes to 24 hours. Then, in order to end the condensation reaction, an additional base can be added or heating can be carried out at 40 to 100 °C. In addition, normal stirring can be further carried out.

[0102] Step (2) in the manufacturing method of the present invention is a step of removing water. After silica is adhered to the surface of cellulose particles, the water is volatilized and removed.

[0103] The volatilization and removal of water can be carried out under normal pressure or reduced pressure (0 to 200 °C), or can be carried out by heating under normal pressure or reduced pressure (preferably 100 to 200 °C). For example, a method of leaving the dispersion standing under heating to remove water can be cited. In addition, as a pretreatment for this operation, the dispersion can be concentrated by methods such as filtration separation, centrifugal separation, and decantation. If necessary, the dispersion can be washed with water or water-soluble alcohol, etc.

[0104] In the case where the powder of the composite particles obtained by volatilizing and removing water undergoes cohesion, it is only necessary to use a crusher such as a jet mill, a ball mill, or a hammer mill to crush it.

[0105] The cellulose particles of the composite particles obtained by the above method are coated with silica. The coating with silica can be confirmed by infrared absorption spectroscopy. In addition, the coating state can be confirmed by observing the surface in an electron microscope photograph. In particular, it is preferably 30% to 95%, preferably 40 to 90%, more preferably 50 to 70% of the specific surface area of the cellulose particles that is coated with silica.

[0106] If the surface coating rate of the cellulose particles is less than 30%, the effect of the siloxane cannot be exhibited. In addition, if the coating rate is 50% or more, the effect of the siloxane is more significantly exhibited. On the other hand, if the coating rate is 95% or less, there is no concern about the generation of siloxane or cohesive particles that are not coated on the cellulose particles and the deterioration of the hand feeling, and the biodegradability effect of the cellulose particles can be surely obtained.

[0107] The volume average particle diameter of the composite particles of the present invention is preferably 1 to 300 μm. More preferably, it is 1 to 150 μm, and still more preferably, it is 1 to 50 μm. Here, the volume average particle diameter of the composite particles of the present invention is the cumulative volume 50% particle diameter obtained from the data measured by using a laser diffraction particle size distribution analyzer (for example, "SALD2100" manufactured by SHIMADZU CORPORATION).

[0108] Furthermore, the composite particles of the present invention can be alkoxylated. As a method for alkoxylation, for example, the method disclosed in JP-A-2008-37714 can be cited. Specifically, this method is: surface-modifying silica with an alcohol (C n H 2n+1 OH) to form an alkoxy group on the surface of the silica. In addition, the value of n is not particularly limited, and for example, it can be set to n < 5.

[0109] In the present invention, the following embodiments are preferred: alkoxylation is carried out by refluxing with boiling alcohol; the water resistance is improved by changing the side chain length of the organic functional group composed of the alkoxy group; the hydrophobic part of the organic functional group is changed according to the side chain length of the alcohol to make the silica surface hydrophobic.

[0110] The composite particles of the present invention only need to be composite particles in which silica is attached to the surface of cellulose particles. That is, the composite particles of the present invention can be composite particles in which only silica is attached to the surface of cellulose particles, or can also be composite particles in which other components are attached to the surface of cellulose particles in addition to silica. Among them, when the other components include rubber particles, since the rubber particles will affect the touch and the like, a better touch or ductility can be obtained when the rubber particles are less. Therefore, the content of rubber particles per 100 parts by mass of cellulose in the composite particles of the present invention is preferably less than 0.1 part by mass, and more preferably, no rubber particles are attached to the surface of the cellulose particles.

[0111] In addition, the composite particles of the present invention preferably include that the coating film of the composite particles has a coefficient of static friction less than 0.50. If the composite particles are such, a cosmetic with excellent smoothness can be obtained.

[0112] [Cosmetics]

[0113] The composite particles of the present invention can be incorporated and used in cosmetics. The incorporation amount of the composite particles relative to the whole cosmetics is preferably 1 to 50% by mass. If it is 1% by mass or more, sufficient effects can be obtained, and if it is 50% by mass or less, there are no obvious adverse conditions such as whitening.

[0114] Examples of cosmetic admixtures other than the composite particles of the present invention include oil agents, solvents, and powders other than the composite particles of the present invention.

[0115] Examples of oil agents include hydrocarbons, silicone oils, triglycerides, ester oils, fats and oils, waxes, higher fatty acids having 12 to 20 carbon atoms, higher alcohols having 8 to 20 carbon atoms, etc. Low-boiling silicone oils, low-boiling isoparaffinic hydrocarbons, triglycerides, and ester oils are particularly preferred. For example, examples of low-boiling silicone oils include octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, tetradecamethylcyclohexasiloxane, etc. Examples of ester oils include fatty acid esters having 6 to 20 carbon atoms or glycerol fatty acid esters, etc.

[0116] The content of the oil agent in the cosmetic varies depending on the dosage form of the cosmetic. Relative to the total amount of the powder and the composite particles of the present invention, it is preferably 0.1 to 95% by mass, and more preferably 1 to 80% by mass. If it is 0.1% by mass or more, the effects such as the smoothness and moisturizing property of the oil agent can be sufficiently exhibited, and if it is 95% by mass or less, the storage stability is good.

[0117] Examples of solvents include lower and middle alcohols, aromatic alcohols, etc., and lower alcohols having 1 to 4 carbon atoms such as isopropyl alcohol are preferred. The content rate of the solvent in the cosmetic of the present invention varies depending on the dosage form of the cosmetic. Relative to the total amount of the powder and the composite particles of the present invention, it is preferably 0.1 to 80% by mass, and more preferably 1 to 50% by mass.

[0118] The powder represents a material that can usually be used in (cosmetic) cosmetics, and there is no particular limitation. Usually, the average particle size is 0.1 to 50 μm, and examples include coloring materials such as inorganic coloring pigments, inorganic white pigments, and organic pigments, pearlescent agents, extender pigments, and organic powders.

[0119] As powder materials, examples include titanium oxide, zirconium oxide, zinc oxide, cerium oxide, magnesium oxide, barium sulfate, calcium sulfate, magnesium sulfate, calcium carbonate, magnesium carbonate, talc, mica, kaolin, sericite, muscovite, synthetic mica, phlogopite, red mica, biotite, lepidolite, silicic acid, silicon dioxide, aluminum silicate, sodium silicate, sodium magnesium silicate, magnesium silicate, magnesium aluminum silicate, calcium silicate, barium silicate, strontium silicate, metal tungstate salts, hydroxyapatite, vermiculite, gibbsite, bentonite, montmorillonite, hectorite, zeolite, ceramic powder, calcium monohydrogen phosphate, aluminum oxide, aluminum hydroxide, boron nitride, boron subnitride, etc.; as organic powder materials, examples include polyamide powder, polyester powder, polyethylene powder, polypropylene powder, polystyrene powder, polyurethane powder, phenylmelamine powder, polymethylphenylmelamine powder, polytetrafluoroethylene powder, polymethyl methacrylate powder, cellulose, silk powder, nylon powder, nylon 12, nylon 6, silicone powder, polymethylsilsesquioxane spherical powder, styrene-acrylic copolymer, divinylbenzene-styrene copolymer, vinyl resin, urea resin, phenolic resin, fluororesin, silicone resin, acrylic resin, melamine resin, epoxy resin, polycarbonate resin, microcrystalline fiber powder, starch powder, lauroyl lysine, etc.; as surfactant metal salt powder materials, examples include zinc stearate, aluminum stearate, calcium stearate, magnesium stearate, zinc myristate, magnesium myristate, zinc palmitate, zinc laurate, zinc cetyl alcohol phosphate, calcium cetyl alcohol phosphate, sodium zinc cetyl alcohol phosphate, etc.; as colored pigments, examples include inorganic red pigments such as red iron oxide, iron oxide, iron hydroxide, iron titanate, etc., inorganic brown pigments such as γ-iron oxide, etc., inorganic yellow pigments such as yellow iron oxide, loess, etc., inorganic black pigments such as black iron oxide, carbon black, etc., inorganic purple pigments such as manganese violet, cobalt violet, etc., inorganic green pigments such as chromium hydroxide, chromium oxide, cobalt oxide, cobalt titanate, etc., inorganic blue pigments such as Prussian blue, ultramarine, etc., pigments obtained by lake formation of tar-based pigments such as Red No. 3, Red No. 104, Red No. 106, Red No. 201, Red No. 202, Red No. 204, Red No. 205, Red No. 220, Red No. 226, Red No. 227, Red No. 228, Red No. 230, Red No. 401, Red No. 505, Yellow No. 4, Yellow No. 5, Yellow No. 202, Yellow No. 203, Yellow No. 204, Yellow No. 401, Blue No. 1, Blue No. 2, Blue No. 201, Blue No. 404, Green No. 3, Green No. 201, Green No. 204, Green No. 205, Orange No. 201, Orange No. 203, Orange No. 204, Orange No. 206, Orange No. 207, etc., and pigments obtained by lake formation of natural pigments such as carminic acid, laccaic acid, carthamin, brazilin, crocin, etc.Examples of pearlescent pigments include mica coated with titanium oxide, mica titanate, mica titanate treated with iron oxide, bismuth oxychloride, bismuth oxychloride coated with titanium oxide, talc coated with titanium oxide, fish scale foil, colored mica coated with titanium oxide, etc.; examples of metal powder pigments include metal powders such as aluminum, gold, silver, copper, platinum, and stainless steel.

[0120] Furthermore, in addition to the above components, other components commonly incorporated in cosmetics, such as surfactants, oily components, high molecular compounds, gelling agents, alkalis, polyhydric alcohols, pH regulators, ultraviolet absorbers, antioxidants, preservatives, anti-inflammatory agents, skin beautifying components, and fragrances, can also be incorporated into the cosmetics of the present invention according to the purpose.

[0121] Examples of the cosmetics of the present invention include color cosmetics such as foundation, face powder, eyeshadow, eyeliner, eyebrow pencil, blush, lipstick, and nail polish, basic cosmetics such as lotion, cream, moisturizing lotion, calamine lotion, sunscreen, suntan lotion, aftershave lotion, pre-shave lotion, facial mask, anti-acne cosmetics, essence, etc., hair cosmetics such as shampoo, hair rinse, hair conditioner, hair color, hair tonic, setting agent, hair growth agent, permanent, etc., body powder, deodorant, hair remover, soap, body shampoo, bath agent, hand soap, perfume, etc. The composite particles of the present invention are preferably used in powder cosmetics such as foundation, face powder, eyeshadow, and eyebrow pencil.

[0122] Examples

[0123] Hereinafter, examples and comparative examples are shown to explain the present invention in more detail, but the present invention is not limited by the following examples. In addition, in the following examples, "parts" and "%" represent parts by mass and mass%, respectively.

[0124] [Example 1]

[0125] In a 500 ml reactor, 100 parts by mass of spherical cellulose particles (A-1) with an average particle size of 7 μm, 830 parts by mass of ion-exchanged water, and 1.6 parts by mass of dodecyltrimethylammonium chloride (cationic BB, a cationic emulsifier manufactured by NOF CORPORATION) were added and stirred for 30 minutes. After cooling to 5°C, 0.5 part by mass of 25% ammonia water was added, and 22.5 parts by mass of tetramethoxysilane (B-1) was added over 20 minutes. After aging at 8°C for 1 hour, 22 parts by mass of 25% ammonia water was added and aged for 1 hour. The temperature was raised to 55°C and aged for 1 hour to obtain a slurry. The slurry was subjected to suction filtration to separate the solid and liquid, and then left standing for drying. It was confirmed by electron microscopy that it was a composite particle with silica attached to the surface of the granular cellulose particles.

[0126] [Example 2]

[0127] In a 500 ml reactor, 100 parts by weight of the powder obtained in Example 1 was added, 830 parts by mass of isopropyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd.) was added, the temperature was raised to 80°C, and reflux was carried out for 10 hours to obtain a slurry. After the slurry was subjected to suction filtration to separate the solid and liquid and then left standing for drying, a powder with excellent fluidity was obtained by monodispersion. When this powder was floated in water and left standing for 5 minutes, the powder maintained a state of floating on the water surface and did not precipitate in the water. Then, when observed after standing for more than 10 hours, precipitation was observed in the water. Therefore, this powder has short-term waterproof properties.

[0128] [Example 3]

[0129] Except that the spherical cellulose particles with an average particle size of 7 μm were replaced with spherical cellulose particles (A-2) with an average particle size of 15 μm, the procedures of Example 1 were repeated to obtain a powder.

[0130] The composite particles were observed using an electron microscope, and it was confirmed that particles with a particle size of approximately 100 nm were present on the particle surface. In addition, using an FT-IR measuring device (manufactured by SHIMADZU CORPORATION), the infrared absorption spectrum was measured by the potassium bromide tablet method. As a result, characteristic absorption was confirmed at wavenumbers 1260 cm -1 and 1100 - 1020 cm -1 . From this, it was confirmed that it was a composite particle with silica attached to the surface of the granular cellulose particles. Figure 1An electron micrograph showing the surface of the above composite particles is presented. Additionally, in FIGS. 2(a) to (c), there are shown an electron micrograph (a) of the surface of the above composite particles, an image (b) obtained by superimposing an elemental mapping image of silicon and an elemental mapping image of carbon analyzed using SwiftED3000 (manufactured by HITACHI CORPORATION) corresponding to the micrograph (a), and an image (c) corresponding to the image (b) showing only the signal of silicon. Although FIG. 2(b) becomes slightly less clear when transformed into a black-and-white image, in FIG. 2(b), the substantially white portions represent signals from carbon, and the colored portions represent signals from silicon. From these electron micrographs, it was confirmed that composite particles with silica attached to the surface of granular cellulose particles were obtained.

[0131] [Example 4]

[0132] Except for replacing the cellulose particles of Example 1 with spherical cellulose particles (A-3) having an average particle diameter of 5 μm, the procedure of Example 1 was repeated to obtain a powder.

[0133] [Comparative Examples 1 to 3]

[0134] Cellulose particles (A-1), (A-2), and (A-3) were subjected to evaluation in an untreated state with respect to silica treatment.

[0135] [Comparative Example 4]

[0136] Except for not adding 25% ammonia before and after adding tetramethoxysilane, the procedure of Example 1 was repeated to obtain composite particles. An electron micrograph is shown in Figure 3 .

[0137] [Comparative Example 5]

[0138] Spherical silica particles (B-2) were subjected to evaluation in an untreated state with respect to any treatment.

[0139] The above-obtained composite particles were evaluated as follows. The results are shown in Tables 1 and 2.

[0140] <Coating Rate>

[0141] Based on electron micrographs of the surfaces of 10 composite particles, the average coating rate was calculated by visual inspection. More specifically, based on images respectively taken in a field of view enlarged up to 10,000 times, the area of the region in the composite particles where silica fine particles were not attached was measured, and the ratio coated with silica was calculated.

[0142] The calculation is performed using the following formula.

[0143] Coating rate (%) = Coated area / Surface area × 100

[0144] <Method for Measuring Touch and Ductility>

[0145] Attach an appropriate amount of powder sample to the finger, touch the black carbon paper and slide instantaneously on the paper surface. Take the feeling during sliding as the touch, and take how far the sliding trace can extend as the ductility, and evaluate according to the following 3 criteria.

[0146] ○: Has a particularly good smooth feeling

[0147] △: Has a relatively good smooth feeling

[0148] ×: The finger feels resistance and has no smooth feeling

[0149] <Method for Measuring Coefficient of Friction>

[0150] Evenly coat and spread approximately 1 g of powder sample on a bionic skin plate (manufactured by Beaulax Co., Ltd.) to make a sample piece. Through HEIDON TYPE-38 (manufactured by Shinto Scientific Co., Ltd.), make the indenter with a 100 g weight placed on it contact the above sample piece vertically, measure the frictional force when it is moved at 3 cm / minute, and calculate the coefficient of friction according to the frictional force. The indenter used has a contact surface diameter of 12 mm and artificial leather Sapphire installed on the contact surface with the sample piece. In addition, for the preferred range of the static coefficient of friction and the dynamic coefficient of friction, both the static coefficient of friction and the dynamic coefficient of friction are preferably 0.01 - 0.50, and more preferably 0.01 - 0.45.

[0151] <Contact Angle>

[0152] Make a sample piece the same as that for the above coefficient of friction measurement, drop a 10 μm water droplet on the sample piece, and use a contact angle meter CA-D type manufactured by Kyowa Interface Science Co., Ltd. to measure the contact angle value after 10 seconds. As a waterproof material, the preferred range is that the contact angle is 90° or more, and more preferably 95° or more.

[0153] <Light Diffusion Intensity (Light Diffusion Property Evaluation)>

[0154] Add 5 g of the powder sample to 45 g of clear lacquer, and disperse it for 2 minutes at 3000 rpm using a Disper Mixer. Drop the dispersion onto a black carbon paper to form a circle with a diameter of 2 cm, and coat it using a 5 MIL coater to form a film. After air drying, measure three different points on the film using a gloss meter and take the average value. The smaller the reflected light intensity at 85°, the more matte the quality and the better the light diffusibility. The preferred range of the light diffusion intensity (85°) is 5 or less.

[0155] [Table 1]

[0156]

[0157] [Table 2]

[0158]

[0159] A-1: Cellulose particles with an average particle size of 7 μm (bulk density of 0.59 g / cm 3 , angle of repose of 47°)

[0160] A-2: Cellulose particles with an average particle size of 15 μm (bulk density of 0.66 g / cm 3 , angle of repose of 49°)

[0161] A-3: Cellulose particles with an average particle size of 5 μm (bulk density of 0.68 g / cm 3 , angle of repose of 51°)

[0162] B-1: Tetramethoxysilane (KBM04, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0163] B-2: Silicon dioxide powder (average particle size of 4 μm, Siloblock S-400, manufactured by Moriroku Company, Ltd.)

[0164] (In addition, the average particle sizes of A-1 to A-3 are the average particle sizes (D50) measured using a laser diffraction particle size distribution measuring device (LA-950V2 manufactured by HORIBA, Ltd.) after dispersing 1 g of the powder sample in water.)

[0165] As shown in Table 1, as the composite particles of the present invention, those of Examples 1 to 4 are all composite particles in which the surface of cellulose particles is coated with silica, and thus exhibit good touch and ductility, and at the same time, the smoothness or light diffusibility is also excellent. Further, the composite particles of Example 2 in which alkoxy modification was carried out have water repellency. On the other hand, as shown in Table 2, for Comparative Examples 1 to 3 in which cellulose particles were used alone, and Comparative Example 4 in which tetramethoxysilane (B-1) was added but silica was not attached, although the touch was good, sufficient ductility was not obtained. In addition, the touch and ductility of Comparative Example 5 in which silica powder was used alone were both poor.

[0166] [Example 5]

[0167] Using the composite particles manufactured in Example 1, a foundation was prepared by blending as shown below.

[0168] Foundation

[0169]

[0170] (Note 1) NS Talc (TALC) JA-46R-3F (manufactured by KAKUHACHI CO,.LTD.)

[0171] [Examples 6 to 8, Comparative Examples 6 to 10]

[0172] Except that the powder was replaced with the composite particles obtained in Examples 2 to 4 and Comparative Examples 1 to 5, a foundation was prepared by blending in the same manner as in Example 5.

[0173] [Example 9]

[0174] Except that the amount of the composite particles used in Example 5 was set to 20%, a foundation was prepared by blending in the same manner as in Example 5.

[0175] For the foundation obtained above, the following evaluation was carried out. The results are shown in Tables 3 and 4.

[0176] [Touch, Smoothness]

[0177] Twenty professional testers were allowed to conduct a use test, and according to the following scoring criteria, the evaluation items related to the touch and smoothness of the cosmetics were evaluated respectively. Then, the scores given by each person were totaled, and the evaluation was carried out according to the following evaluation criteria.

[0178] (Scoring Criteria)

[0179] 5 points: Very excellent

[0180] 4 points: Excellent

[0181] 3 points: Ordinary

[0182] 2 points: Poor

[0183] 1 point: Very poor

[0184] (Evaluation criteria)

[0185] ◎: The total score is above 80 points

[0186] ○: The total score is above 60 points and less than 80 points

[0187] △: The total score is above 40 points and less than 60 points

[0188] ×: The total score is less than 40 points

[0189] [Table 3]

[0190]

[0191] [Table 4]

[0192]

[0193] As shown in Table 3 and Table 4 above, the touch and smoothness of the foundation using untreated cellulose particles or silica powder on the surface are poor. In contrast, compared with the untreated cellulose particles on the surface, the touch and smoothness of the foundation obtained from the cellulose-silica composite particles of the present invention are excellent.

[0194] This specification includes the following inventions.

[0195] [1]: A composite particle, characterized in that it comprises particles of cellulose or a cellulose derivative, and silica attached to the surface of the particles, the silica being a polymer of tetraalkoxysilane, and the tetraalkoxysilane being 1 to 60 parts by mass relative to 100 parts by mass of the particles.

[0196] [2]: The composite particle according to [1] above, characterized in that the particles of cellulose or a cellulose derivative have a volume average particle diameter of 1 to 300 μm.

[0197] [3]: The composite particle according to [1] or [2] above, characterized in that the tetraalkoxysilane is tetramethoxysilane.

[0198] [4]: The composite particle according to any one of [1] to [3] above, characterized in that the coating film containing the composite particle has a coefficient of static friction of less than 0.50.

[0199] [5]: The composite particle according to any one of [1] to [4] above, characterized in that the composite particle has been alkoxylated.

[0200] [6]: A composite particle, characterized in that it comprises particles of cellulose or a cellulose derivative, and silica adhered to the surface of the particles, and more than 50% of the specific surface area of the particles is coated with silica.

[0201] [7]: The composite particle according to the above [6], characterized in that the particles of cellulose or a cellulose derivative have a volume average particle diameter of 1 to 300 μm.

[0202] [8]: The composite particle according to the above [6] or the above [7], characterized in that the silica is a polymer of tetraalkoxysilane.

[0203] [9]: The composite particle according to the above [8], characterized in that the tetraalkoxysilane is tetramethoxysilane.

[0204]

[10] : The composite particle according to any one of the above [6] to [9], characterized in that the coating film containing the composite particle has a coefficient of static friction of less than 0.50.

[0205]

[11] : The composite particle according to any one of the above [6] to

[10] , characterized in that the composite particle has been alkoxylated.

[0206]

[12] : A method for manufacturing a composite particle, the composite particle comprising particles of cellulose or a cellulose derivative, and silica adhered to the surface of the particles, the manufacturing method being characterized in that it includes: step (1), in the presence of (A) particles of cellulose or a cellulose derivative, water and an alkali, hydrolyzing and condensing (B) tetraalkoxysilane in an amount of 1 to 60 parts by mass relative to 100 parts by mass of the (A) particles to form silica, and adhering the silica to the surface of the (A) particles to obtain the composite particle.

[0207]

[13] : The method for manufacturing a composite particle according to the above

[12] , characterized in that after the step (1), it further includes: step (2), a step of removing water.

[0208]

[14] : A cosmetic, characterized in that it contains the composite particle according to any one of the above [1] to

[11] .

[0209]

[15] : The cosmetic according to the above

[14] , characterized in that it contains the composite particle in an amount of 1 to 50% by mass relative to the total amount of the cosmetic.

[0210] In addition, the present invention is not limited by the above embodiments. The above embodiments are illustrative, and technical solutions having the same constitution as the technical concept described in the claims of the present invention and exhibiting the same effects are included in the technical scope of the present invention.

[0211] Industrial applicability

[0212] When the composite particles of the present invention are blended and used in cosmetics, the cosmetics can be provided with slidability, a soft touch, water resistance, etc., and can be blended in various cosmetics such as hair cosmetics, makeup cosmetics, and sunscreen. In addition, biodegradability effects can be expected for the composite powder of the present invention and the cosmetics containing the composite powder.

Claims

1. A composite particle, characterized in that, It contains particles of cellulose or a cellulose derivative, and silica attached to the surface of the particles. The silica is a polymer of tetraalkoxysilane, and the tetraalkoxysilane is 1 to 60 parts by mass relative to 100 parts by mass of the particles.

2. The composite particles according to claim 1, characterized in that, The particles of cellulose or a cellulose derivative have a volume average particle diameter of 1 to 300 μm.

3. The composite particles according to claim 1, characterized in that, The tetraalkoxysilane is tetramethoxysilane.

4. The composite particle according to claim 1, wherein The coating film containing the composite particles has a coefficient of static friction of less than 0.

50.

5. The composite particles according to claim 1, wherein, The composite particles have been alkoxylated.

6. A composite particle, characterized in that, It contains particles of cellulose or a cellulose derivative, and silica attached to the surface of the particles. More than 50% of the specific surface area of the particles is coated with silica.

7. The composite particle according to claim 6, wherein The particles of cellulose or a cellulose derivative have a volume average particle diameter of 1 to 300 μm.

8. The composite particle according to claim 6, wherein, The silica is a polymer of tetraalkoxysilane.

9. The composite particle according to claim 8, wherein, The tetraalkoxysilane is tetramethoxysilane.

10. The composite particle according to claim 6, wherein, The coating film containing the composite particles has a coefficient of static friction of less than 0.

50.

11. The composite particle according to claim 6, wherein The composite particles have been alkoxylated.

12. A method for manufacturing composite particles, the composite particles containing particles of cellulose or a cellulose derivative, and silica attached to the surface of the particles. The manufacturing method is characterized in that it includes: Step (1), in the presence of (A) particles of cellulose or a cellulose derivative, water, and an alkali, hydrolyze and condense (B) tetraalkoxysilane, which is 1 to 60 parts by mass relative to 100 parts by mass of the (A) particles, to form silica, and attach the silica to the surface of the (A) particles to obtain the composite particles.

13. The manufacturing method of the composite particles according to claim 12, characterized in that, After the step (1), it further includes: step (2), a step of removing water.

14. A cosmetic, characterized in that, It contains the composite particles according to any one of claims 1 to 11.

15. The cosmetic according to claim 14, wherein The composite particles are contained in an amount of 1 to 50% by mass relative to the total amount of the cosmetic.

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