Solid emulsifier for oil-in-water emulsion, method for producing oil-in-water emulsion, oil-in-water emulsion, and cosmetic composition

Abstract

The purpose of the present invention is to provide: a solid emulsifier for an oil-in-water emulsion, which is used for producing an oil-in-water emulsion that has a low feeling of astringency when used as a cosmetic and has a good feeling of use; a method for producing an oil-in-water emulsion; and an oil-in-water emulsion. A solid emulsifier for an oil-in-water emulsion, which contains metal oxide particles having a volume average particle diameter of 0.2-0.4 [mu] m, a specific surface area of 5-20 m2 / g, and a degree of hydrophobicity defined in the present invention of 5-35.

Description

Technical Field

[0001] The present invention relates to a solid emulsifier for oil-in-water emulsion, a method for producing the oil-in-water emulsion, the oil-in-water emulsion and a cosmetic composition. Background Art

[0002] Oil-in-water (O / W) and water-in-oil (W / O) emulsions are used in cosmetics, etc. Most emulsifiers used in emulsions are surfactants, and cosmetics mixed with surfactants may feel sticky or slimy when applied to the skin, resulting in a poor feel. When applied to the skin, irritation to the skin may become a problem. In addition, cosmetics may fall off due to water such as sweat, and water resistance may become a problem.

[0003] As a non-irritating and water-resistant cosmetic, an oil-in-water emulsion cosmetic that utilizes Pickering emulsification based on inorganic fine particles having an average particle size of less than 200 nm such as silica particles without adding a surfactant has been developed in recent years (Patent Document 1).

[0004] However, there is a problem that the texture is poor due to the astringency caused by the inorganic fine particles.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application No. 2001-518111 Summary of the invention

[0008] Problems to be solved by the invention

[0009] The present invention aims to provide a solid emulsifier for an oil-in-water emulsion, a method for producing an oil-in-water emulsion, an oil-in-water emulsion and a cosmetic composition for producing an oil-in-water emulsion having low astringency and good feel when used as a cosmetic.

[0010] Means for solving problems

[0011] The present inventors have conducted intensive studies to solve the above-mentioned problems and have completed the present invention.

[0012] That is, the present invention relates to a solid emulsifier for oil-in-water emulsion, comprising metal oxide particles, wherein the volume average particle size of the metal oxide particles is 0.2 to 0.4 μm, and the specific surface area is 5 to 20 m 2 / g, and a hydrophobicity of 5 to 35; a method for producing an oil-in-water emulsion, which is a method for producing an oil-in-water emulsion in which an oil phase component is dispersed in an aqueous phase component, and comprises: a dispersion step, in which the solid emulsifier for the oil-in-water emulsion of the present invention is dispersed in an aqueous solvent to obtain an aqueous dispersion; and an emulsification step, in which the oil phase component is added to the aqueous dispersion while stirring the aqueous dispersion; an oil-in-water emulsion, which comprises the solid emulsifier for the oil-in-water emulsion of the present invention.

[0013] Effects of the Invention

[0014] According to the present invention, a solid emulsifier for an oil-in-water emulsion, a method for producing an oil-in-water emulsion, an oil-in-water emulsion, and a cosmetic composition can be provided for producing an oil-in-water emulsion having low astringency and good feel when used as a cosmetic. DETAILED DESCRIPTION

[0015] Hereinafter, the present invention will be described in detail.

[0016] The solid emulsifier for oil-in-water emulsion of the present invention comprises metal oxide particles, wherein the volume average particle size of the metal oxide particles is 0.2 to 0.4 μm, and the specific surface area is 5 to 20 m 2 / g, hydrophobicity is 5 to 35.

[0017] Examples of the metal oxide particles include particles of metal oxides and composite oxides such as silicon dioxide (SiO2), aluminum oxide (Al2O3), titanium dioxide (TiO2), zinc oxide (ZnO2), and zirconium oxide (ZrO2), and silicon dioxide particles are more preferred.

[0018] It should be noted that, in this specification, semimetals such as silicon (Si) are treated as substances included in metals.

[0019] When the volume average particle size of the metal oxide particles is 0.2 to 0.4 μm, the emulsion stability is improved, and when the solid emulsifier for oil-in-water emulsion of the present invention is used as a cosmetic, astringent feeling is less likely to be felt.

[0020] If the specific surface area of ​​metal oxide particles is 5 to 20 m 2 / g, when the solid emulsifier for oil-in-water emulsion of the present invention is used as a cosmetic, astringent feeling derived from the metal oxide particles is less likely to occur.

[0021] It should be noted that the specific surface area of ​​the metal oxide particles refers to the BET specific surface area obtained by the BET method. The BET method is a gas adsorption method in which gas particles such as nitrogen are adsorbed on solid particles and the specific surface area is measured based on the amount of adsorption. The single molecule adsorption amount VM is calculated using the BET formula based on the relationship between the pressure P and the adsorption amount V, thereby determining the specific surface area.

[0022] In this specification, the specific surface area refers to a value measured by the BET multipoint method described in JIS 8830:2013.

[0023] The hydrophobicity of the metal oxide particles is more preferably 10 to 32.5, further preferably 15 to 30, and particularly preferably 20 to 30.

[0024] When the hydrophobicity is within this range, the metal oxide particles can be stably adsorbed on the interface of oil droplets in water for a long period of time, and thus can be used as a solid emulsifier for oil-in-water emulsions.

[0025] In addition, in this specification, the hydrophobicity of "metal oxide particles" means the value measured by the following method.

[0026] <Method for measuring hydrophobicity>

[0027] (1) Add 50 mL of ion-exchanged water to a 100 mL beaker.

[0028] (2) 0.2 g of metal oxide particles as a test sample was added to the beaker of (1), and stirred with a PTFE stirrer (length 30 mm × diameter 8 mm). The stirring speed was adjusted so that when the stirring state in the beaker was observed from the side of the beaker, the bottom of the vortex generated by stirring was higher than the midpoint of the distance from the liquid surface to the bottom of the beaker.

[0029] It should be noted that the “liquid surface” refers to the liquid surface of the ion-exchanged water containing the metal oxide particles in a static state before stirring.

[0030] (3) While continuing to stir, 0.5 mL of methanol was added dropwise using a burette. Stirring was stopped after 30 seconds had passed since the stirring was stopped, and it was determined whether metal oxide particles were visually observed on the liquid surface after 30 seconds had passed since the stirring was stopped.

[0031] (4) Step (3) is repeated until metal oxide particles can no longer be visually confirmed on the liquid surface in step (3).

[0032] (5) Calculate the volume percentage of the volume of the methanol added in (3) and (4) relative to the total volume of the ion-exchanged water in the beaker (50 mL) and the volume (mL) of the methanol added in (3) and (4), and use the value as the hydrophobicity.

[0033] Next, a method for producing metal oxide particles having the above-mentioned parameters will be described.

[0034] First, prepare a particle having a volume average particle size of 0.2 to 0.4 μm and a specific surface area of ​​5 to 20 m 2 / g, metal oxide particles that have not been surface treated (hereinafter, also referred to as "surface-untreated metal oxide particles").

[0035] The surface untreated metal oxide particles can be obtained by a deflagration method in which a metal powder is dispersed in an oxygen gas stream and ignited to oxidize it, a melting method in which the metal powder is melted and spheroidized in a flame, etc. Usually, the metal oxide powder obtained by the deflagration method is a true spherical particle. Among these methods, the deflagration method is most preferred because it is a true spherical particle and can be chemically modified uniformly on the surface.

[0036] By chemically modifying the surface of such surface-untreated metal oxide particles with a hydrophobic functional group (hydrocarbon group or the like), the hydrophobicity of the metal oxide particles can be adjusted to 5 to 35.

[0037] By using such a method, metal oxide particles having the above-mentioned parameters can be produced.

[0038] Next, as a method for producing metal oxide particles having the above-mentioned parameters, a case of producing silica particles will be specifically described as an example.

[0039] First, prepare a particle having a volume average particle size of 0.2 to 0.4 μm and a specific surface area of ​​5 to 20 m 2 / g, silica particles without surface treatment.

[0040] The silica particles are preferably silica particles obtained by a deflagration method, a fusion method, or the like (hereinafter also referred to as “deflagration method silica particles” and “fusion method silica particles,” respectively), and deflagration method silica particles are preferred.

[0041] Next, the hydrophobicity of the silica particles can be adjusted to 5 to 35 by chemically modifying at least a portion of the surface of the silica particles with a hydrophobic functional group (hydrocarbon group or the like).

[0042] Silica particles chemically modified with hydrophobic functional groups (hydrocarbon groups, etc.) can be obtained by surface-treating the silanol groups present on the surfaces of deflagration silica particles, fused silica particles, etc., by silylation using a known silane coupling agent (alkoxysilane, organosilazane, etc.).

[0043] The surface treatment can be carried out in a dry state of the silica particles or in a certain liquid. The surface treatment agent during the surface treatment can be added after being vaporized to make it react, or it can be added after being dissolved in a certain solvent (in the case where the surface treatment agent is a liquid, it can also be in its original state) to make it react. As the solvent or liquid, general solvents such as methyl ethyl ketone, acetone, methanol, ethanol, propanol, butanol, and water can be used.

[0044] In such silica particles, the carbon content is preferably 20 to 80% by mass, more preferably 50 to 80% by mass of the saturated content based on the total mass of the silica particles. The carbon content can be measured using a carbon analyzer (eg, EMIA-Pro (manufactured by Horiba, Ltd.)).

[0045] The chemical modification of the surface of the silica particles preferably uses alkoxysilanes and organosilazanes. Examples of alkoxysilanes include methyltrimethoxysilane, dimethyltrimethoxysilane, phenyltrimethoxysilane, dimethoxydiphenylsilane, n-propyltrimethoxysilane, hexyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propylethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, and the like. Examples of organosilazanes include tetramethyldisilazane, hexamethyldisilazane, pentamethyldisilazane, and the like. From the perspective of use in cosmetics, hexamethyldisilazane is most preferred.

[0046] The bond obtained by the reaction between the silanol group and the organosilazane is not easily hydrolyzed and is not easily cut over time, so that a solid emulsifier for an oil-in-water emulsion with excellent stability over time can be obtained.

[0047] As the silica particles before the surface treatment, commercially available silica particles can be used. For example, as the silica particles produced by the deflagration process or the fused process, Admafine SO-C1 (deflagration process silica particles manufactured by Admatechs) can be used.

[0048] <Method for producing oil-in-water emulsion>

[0049] The first embodiment of the method for producing an oil-in-water emulsion of the present invention is a method for producing an oil-in-water emulsion in which an oil phase component is dispersed in an aqueous phase component, and the method for producing an oil-in-water emulsion comprises: a dispersing step in which the solid emulsifier for the oil-in-water emulsion of the present invention is dispersed in an aqueous solvent to obtain an aqueous dispersion; and an emulsifying step in which the oil phase component is added to the aqueous dispersion while stirring the aqueous dispersion.

[0050] [Dispersion process]

[0051] In this step, the oil-in-water emulsion of the present invention is dispersed in an aqueous solvent using a solid emulsifier.

[0052] In the dispersing step, alcohol or a pH adjuster may be added to the aqueous solvent as needed.

[0053] In this step, the solid emulsifier for oil-in-water emulsion is added to the aqueous solvent and stirred using a known disperser such as a homomixer, whereby the solid emulsifier for oil-in-water emulsion can be dispersed in the aqueous solvent.

[0054] In addition, the alcohol and pH adjuster are preferably added to the aqueous solvent before the solid emulsifier for oil-in-water emulsion is added. That is, it is preferred to add the alcohol and pH adjuster to the aqueous solvent, and add the solid emulsifier for oil-in-water emulsion while stirring the aqueous solvent to disperse it.

[0055] The aqueous solvent is preferably an aqueous solution containing water and / or alcohol.

[0056] In addition, as water, purified water and ionized water are preferred.

[0057] As the alcohol, it is preferable to use an alcohol having a water solubility of 500 g / L or more at 20° C. As preferred alcohols, ethanol (infinitely soluble in water), propylene glycol (infinitely soluble in water), dipropylene glycol (infinitely soluble in water), 1,3-butylene glycol (infinitely soluble in water), isopentyl glycol (infinitely soluble in water), glycerol (infinitely soluble in water), polyethylene glycol (PEG-8, etc.) (water solubility of 1000 g / L at 20° C.) and the like can be used.

[0058] The alcohol in the aqueous dispersion is preferably 10 to 55 parts by mass based on 100 parts by mass of water.

[0059] The aqueous dispersion obtained by dispersing the solid emulsifier for oil-in-water emulsion preferably has a pH of 7 to 14 at 25°C. The aqueous dispersion preferably has a pH of 7 to 14 at 25°C because the dispersion stability of the solid emulsifier for oil-in-water emulsion in the aqueous solvent is improved.

[0060] A pH adjuster may be used to adjust the pH of the aqueous dispersion to 7 to 14 at 25° C. As the pH adjuster, sodium hydroxide, potassium hydroxide, arginine, triethanolamine, citric acid, ascorbic acid, glycolic acid, succinic acid, or the like may be used.

[0061] The mass ratio of the solid emulsifier for oil-in-water emulsion contained in the aqueous dispersion is preferably 1 to 30 mass % based on the total mass of the aqueous dispersion.

[0062] More preferably, the aqueous dispersion contains an alcohol having a water solubility of 500 g / L or more at 20°C, and the pH of the aqueous dispersion at 25°C is 7 to 14.

[0063] [Emulsification process]

[0064] In this step, the oil phase component is added to the aqueous dispersion obtained in the dispersion step while stirring the aqueous dispersion.

[0065] The emulsification step can be performed by gradually adding the oil phase component while stirring the aqueous dispersion at room temperature (preferably 15 to 25° C.) with a homomixer.

[0066] By carrying out this step, an oil-in-water emulsion can be produced.

[0067] The method for producing an oil-in-water emulsion of the present invention preferably includes, after the emulsification step, an aqueous solvent additionally adding step of additionally adding an aqueous solvent while maintaining stirring.

[0068] By additionally adding the aqueous solvent, the dispersibility of the solid emulsifier for oil-in-water emulsion in water can be reduced, and the solid emulsifier for oil-in-water emulsion can be oriented to the oil phase interface.

[0069] In the method for producing an oil-in-water emulsion of the present invention, after the aqueous solvent additional adding step, an aqueous thickener adding step of adding an aqueous thickener and a pH adjusting step of adding a pH adjuster may be performed.

[0070] Alternatively, the pH of the oil-in-water emulsion may be adjusted to 6.0 to 8.0, and then degassed and allowed to stand overnight at 25 degrees.

[0071] In the method for producing an oil-in-water emulsion of the present invention, in the dispersion step, water-soluble ingredients that can be added to cosmetics, such as water-soluble ultraviolet absorbers, preservatives, moisturizers, polymers, amino acids and amino acid derivatives, sugars and sugar derivatives, fragrances, colorants, metal ion chelators, antioxidants, and drugs, can be added to the aqueous solvent.

[0072] In the method for producing an oil-in-water emulsion of the present invention, other ingredients that can be added to cosmetics, such as wax, solid oils and fats, solid waxes, higher fatty acids, oil-soluble ultraviolet absorbers, powders, emollients, polymers, amino acid derivatives, sugar derivatives, fragrances, colorants, antioxidants, and physiologically active substances, can be added to the oil phase components used in the emulsification step.

[0073] Next, the method for producing the oil-in-water emulsion according to the second embodiment of the present invention will be described.

[0074] Another embodiment of the method for producing an oil-in-water emulsion of the present invention is a method for producing an oil-in-water emulsion comprising the following steps: a dispersion step of dispersing the above-mentioned solid emulsifier for the oil-in-water emulsion of the present invention in an oily component to obtain an oily dispersion; and an emulsification step of adding the above-mentioned aqueous phase component to the above-mentioned oily dispersion while stirring the above-mentioned oily dispersion.

[0075] In the method for producing an oil-in-water emulsion according to the first aspect of the present invention, the solid emulsifier for the oil-in-water emulsion according to the present invention is dispersed in an aqueous solvent to obtain an aqueous dispersion, and then an oil phase component is added to the aqueous dispersion. However, in the method for producing an oil-in-water emulsion according to the second aspect of the present invention, the solid emulsifier for the oil-in-water emulsion is dispersed in an oily component to obtain an oily dispersion, and then an aqueous phase component is added, which is different from the method for producing an oil-in-water emulsion.

[0076] In this way, even if the solid emulsifier for oil-in-water emulsion of the present invention is dispersed in the oil phase component first, the oil-in-water emulsion can be produced.

[0077] The materials and the like used in the method for producing an oil-in-water emulsion in the second embodiment of the present invention are preferably the same as the materials and the like used in the method for producing an oil-in-water emulsion in the first embodiment of the present invention.

[0078] The method for producing an oil-in-water emulsion of the present invention can produce an oil-in-water emulsion containing the solid emulsifier for oil-in-water emulsion of the present invention.

[0079] In addition, the oil-in-water emulsion containing the solid emulsifier for oil-in-water emulsions of this invention is one aspect of this invention.

[0080] <Oil-in-water emulsion>

[0081] The oil-in-water emulsion of the present invention contains the above-mentioned solid emulsifier for oil-in-water emulsion of the present invention.

[0082] The oil-in-water emulsion comprises a water phase component and an oil phase component, and the oil phase component is dispersed in the water phase component.

[0083] The water phase component preferably comprises 30 to 99% by volume of the total amount of the oil-in-water emulsion, and the oil phase component preferably comprises 1 to 70% by volume of the total amount of the oil-in-water emulsion. The water phase component contains an aqueous solvent and may contain an aqueous thickener or a pH adjuster as required.

[0084] As aqueous solvents, in addition to pure water and ionized water, aqueous solvents containing alcohol in pure water and ionized water can be cited. As alcohols, for example, monohydric alcohols such as ethanol, 3-methoxy-1-butanol or 3-methoxy-3-methyl-1-butanol; dihydric alcohols such as propylene glycol, dipropylene glycol, 1,3-butylene glycol, isopentyl glycol or tetraethylene glycol; or polyhydric alcohols such as glycerol, diglycerol, polyglycerol or polyethylene glycol (PEG-8, etc.); sugars such as trehalose and glycosyl trehalose and sugar derivatives can be cited.

[0085] From the viewpoint of dispersibility of the solid emulsifier, ethanol, propylene glycol, dipropylene glycol, 1,3-butylene glycol, isoprene glycol, glycerin, and polyethylene glycol are preferred.

[0086] As aqueous thickeners, water-soluble natural polymers, semi-synthetic polymers, synthetic polymers, clay minerals, etc. can be cited. For example, natural polymers can include xanthan gum, guar gum and cellulose nanofibers, semi-synthetic polymers can include derivatives of polysaccharides such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose and carboxymethyl cellulose, synthetic polymers can include polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylic acid and sodium acrylate grafted starch, and clay minerals can include bentonite, montmorillonite, etc. Among them, hydroxyethyl cellulose, cellulose nanofibers, polyacrylic acid and sodium acrylate grafted starch can be preferably cited. The amount of the thickener is preferably about 0.01% by mass to 5% by mass relative to the total amount of the oil-in-water emulsion.

[0087] As the pH adjuster, sodium hydroxide, potassium hydroxide, arginine, triethanolamine, citric acid, ascorbic acid, glycolic acid, succinic acid or the like can be used. The amount of the pH adjuster is preferably 1% by mass or less based on the total amount of the oil-in-water emulsion.

[0088] The water phase component of the oil-in-water emulsion of the present invention may contain water-soluble ingredients that can be added to cosmetics, such as water-soluble ultraviolet absorbers, preservatives, humectants, polymers, amino acids and amino acid derivatives, sugars and sugar derivatives, fragrances, colorants, metal ion chelators, antioxidants, and drugs, within the range that does not impair the effects of the present invention.

[0089] As the oil phase component, an oily component that can be added to cosmetics can be used, and at least one selected from the group consisting of natural oils and fats, silicone oils, hydrocarbon oils, and synthetic ester oils is preferred.

[0090] Examples of the natural oils and fats include avocado oil, camellia oil, tortoise oil, macadamia oil, corn oil, mink oil, olive oil, rapeseed oil, egg yolk oil, sesame oil, almond oil, wheat germ oil, camellia oil, castor oil, linseed oil, safflower oil, cottonseed oil, perilla oil, soybean oil, peanut oil, tea seed oil, coconut oil, rice bran oil, Chinese tung oil, Japanese tung oil, jojoba oil, and germ oil.

[0091] Examples of the silicone oil include cyclic polysiloxanes such as cyclopentasiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane; chain polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxane, and octylpolymethylsiloxane; modified polysiloxanes such as amino-modified polysiloxane, polyether-modified polysiloxane, polyether-modified dimethylpolysiloxane, alkyl-modified polysiloxane, and fluorine-modified polysiloxane, or crosslinked products thereof.

[0092] Examples of the hydrocarbon oil include isododecane, isohexadecane, squalane, squalene, paraffin, light isoparaffin, liquid paraffin, hydrogenated poly(C6-12 olefin), and pristane.

[0093] Examples of the synthetic ester oil include tri(ethylhexanoin), isopropyl myristate, octyldodecyl myristate, isopropyl palmitate, hexyl laurate, decyl oleate, hexyldecyl dimethyloctanoate, lanolin acetate, isocetyl stearate, hexyldecyl isostearate, cetyl ethylhexanoate, neopentyl glycol dicaprate, diisostearyl malate, glyceryl diisostearate, trimethylolpropane tri(ethyl) Hexanoate, Trimethylolpropane Triisostearate, Pentaerythrityl Tetraethylhexanoate, Glyceryl Triethylhexanoate, Triisopalmitin, Trimethylolpropane Triisostearate, Ethylhexyl Palmitate, Trimyristin, Oleyl Oleate, Diethylhexyl Sebacate, Isocetyl Myristate, Hexyldecyl Palmitate, Diisopropyl Sebacate, Diethylhexyl Succinate, Ethylhexyl Palmitate, Caprylic / Capric Triglyceride.

[0094] The oil phase component of the oil-in-water emulsion of the present invention may contain other ingredients that can be added to cosmetics, such as waxes, solid oils and fats, solid waxes, higher fatty acids, oil-soluble ultraviolet absorbers, powders, emollients, polymers, amino acid derivatives, sugar derivatives, fragrances, colorants, antioxidants, and physiologically active substances, within the range that does not impair the effects of the present invention.

[0095] <Cosmetic Composition>

[0096] The cosmetic composition of the present invention comprises the above-mentioned oil-in-water emulsion of the present invention.

[0097] As long as the effects of the present invention are not impaired, known components used in cosmetics can be appropriately blended into the cosmetic composition of the present invention according to the use and purpose.

[0098] Examples of known components that can be incorporated into the cosmetic composition of the present invention include oil components, surfactants, water-miscible organic solvents, thickeners, inorganic powders, acids, alkalis, and sugars.

[0099] Examples of the oil component include oils / waxes, hydrocarbons, higher fatty acids, higher alcohols, and esters.

[0100] Examples of the oil / wax include almond oil, olive oil, hardened oil, camellia oil, castor oil, coconut oil, silicone oil, beeswax, lanolin, and carnauba wax.

[0101] The hydrocarbon includes linear or branched hydrocarbon oils, and specific examples thereof include squalane, ceresin, paraffin, liquid paraffin, and vaseline.

[0102] The higher fatty acids include fatty acids having 12 to 30 carbon atoms, and specifically, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, undecylenic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), isostearic acid, 12-hydroxystearic acid, and the like.

[0103] The higher alcohols include alcohols having 8 to 30 carbon atoms, specifically, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, behenyl alcohol, cetyl alcohol, oleyl alcohol, isostearyl alcohol, hexyldodecanol, octyldodecanol, cetearyl alcohol, 2-decyltetradecyl alcohol, cholesterol, phytosterol, polyoxyethylene cholesterol ether, monostearyl glyceryl ether (baty alcohol), monooleyl glyceryl ether (baty alcohol), etc.

[0104] The ester includes ester oils having 3 to 100 carbon atoms, and specifically, butyl stearate, cetyl lactate, myristyl lactate, isopropyl palmitate, isopropyl myristate, octyldodecyl myristate, myristyl myristate, hexyl laurate, glyceryl monostearate, and di-2-heptylundecanoic acid glyceryl.

[0105] As the surfactant, there are included nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants.

[0106] Examples of the nonionic surfactant include aliphatic alcohol (8 to 24 carbon atoms) alkylene oxide (2 to 8 carbon atoms) adducts (polymerization degree = 1 to 100) [oleyl alcohol ethylene oxide 11 mol adduct, etc.], (poly)oxyalkylene (2 to 8 carbon atoms, polymerization degree = 1 to 100) glycol higher fatty acid (8 to 24 carbon atoms) esters [monostearic acid polyethylene glycol ester (polymerization degree = 20) and distearic acid polyethylene glycol ester (polymerization degree = 30) and the like], poly (2 to 10 valent or more) alcohol fatty acid (8 to 24 carbon atoms) esters [propylene glycol monolaurate, glyceryl monostearate, ethylene glycol monostearate and sorbitan monolaurate and the like], poly (2 to 10 valent or more) alcohol higher fatty acid (8 to 24 carbon atoms) esters (poly)cyclohexane Alkylene oxide adducts (alkylene carbon number 2-8, polymerization degree = 1-100) [sorbitan monolaurate ethylene oxide (polymerization degree = 10) adduct and methyl glucose dioleate ethylene oxide (polymerization degree = 50) adduct, etc.], fatty acid N-hydroxyalkylamides [1:1 coconut oil fatty acid diethanolamide and 1:1 lauric acid diethanolamide, etc.], alkyl (carbon number 1-22) (poly)oxyalkylene (carbon number 2-8, polymerization degree = 1-100) phenyl ether, alkyl (carbon number 8-24) (poly)oxyalkylene (carbon number 2-8, polymerization degree = 1-100)-aminoalkyl (carbon number 8-24) ether and alkyl (carbon number 8-24) dialkyl (carbon number 1-6) amine oxides [lauryl dimethylamine oxide, etc.], etc.

[0107] Examples of the anionic surfactant include alkyl ether carboxylic acids having 8 to 24 carbon atoms or their salts, alkyl (poly)oxyethylene ether carboxylic acids having 8 to 24 carbon atoms or their salts [sodium (poly)oxyethylene (polymerization degree = 1 to 100) lauryl ether acetate and disodium (poly)oxyethylene (polymerization degree = 1 to 100) lauryl sulfosuccinate, etc.], alkyl sulfate ester salts having 8 to 24 carbon atoms and alkyl (poly)oxyethylene sulfate ester salts having 8 to 24 carbon atoms [sodium lauryl sulfate, sodium lauryl (poly)oxyethylene (polymerization degree = 1 to 100) sulfate and triethanolamine lauryl (poly)oxyethylene (polymerization degree = 1 to 100) sulfate, etc.], coconut oil fatty acid monoethanolamide sulfuric acid, Sodium sulfonic acid salt, alkylphenyl sulfonate having 8 to 24 carbon atoms [sodium dodecylbenzenesulfonate, etc.], alkyl phosphate ester salt having 8 to 24 carbon atoms and alkyl (poly)oxyethylene phosphate ester salt having 8 to 24 carbon atoms [sodium lauryl phosphate and sodium (poly)oxyethylene (degree of polymerization = 1 to 100) lauryl ether phosphate, etc.], fatty acid salt [sodium laurate and triethanolamine laurate, etc.], acylated amino acid salt [sodium coconut oil fatty acid methyl taurine, sodium coconut oil fatty acid sarcosinate, coconut oil fatty acid sarcosine triethanolamine, N-coconut oil fatty acid acyl-L-glutamate triethanolamine, sodium N-coconut oil fatty acid acyl-L-glutamate and sodium lauroyl methyl-β-alanine, etc.].

[0108] Examples of the cationic surfactant include quaternary ammonium salt type [stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, distearyldimethylammonium chloride, and ethylsulfate lanolin fatty acid aminopropylethyldimethylammonium, etc.] and amine salt type [stearic acid diethylaminoethylamide lactylate, dilaurylamine hydrochloride, and oleylamine lactylate, etc.] and the like.

[0109] Examples of the amphoteric surfactant include betaine-type amphoteric surfactants [coconut oil fatty acid amide propyl dimethylaminoacetic acid betaine, lauryl dimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, lauryl hydroxysulfobetaine, and lauryl amide ethyl hydroxyethyl carboxymethyl betaine hydroxypropyl sodium phosphate, etc.] and amino acid-type amphoteric surfactants [sodium β-laurylaminopropionate, etc.].

[0110] Specific examples of the water-miscible organic solvent include ethanol, isopropanol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, glycerol, diglycerol, polyglycerol, 3-methyl-1,3-butanediol, 1,3-butanediol, 1,2-pentanediol, and 1,2-hexanediol.

[0111] Examples of the thickener include guar gum, starch, carboxymethyl cellulose, acetyl methyl cellulose, polyvinyl alcohol, and sodium polyacrylate.

[0112] Examples of the inorganic powder include zinc oxide, titanium oxide, barium sulfate, calcium sulfate, calcium carbonate, talc, mica, kaolin, mica, silicic acid, aluminum silicate, hydroxyapatite, vermiculite, HIGILITE (aluminum hydroxide), bentonite, montmorillonite, hectorite, zeolite, ceramic powder, alumina, silica, and silylated silica.

[0113] Examples of the acid include citric acid, tartaric acid, lactic acid, phosphoric acid, etc. Examples of the base include hydroxides of alkali metals (sodium, potassium, etc.) or alkaline earth metals (calcium, etc.), ammonia water, triethanolamine, diethanolamine, monoethanolamine, etc.

[0114] Examples of the sugar include mannitol, sorbitol, xylitol, maltitol, erythritol, pentaerythritol, glucose, sucrose, fructose, lactose, maltose, xylose, and trehalose.

[0115] In addition to the above, the cosmetics of the present invention may also contain ingredients commonly used in cosmetics [colorants, fragrances, hormones, vitamins, photosensitizers, plant / animal extracts, ultraviolet absorbers, antioxidants, preservatives / bactericides, antiperspirants / deodorants, etc. listed in the latest cosmetic science (published by Yakuji Nippo).]

[0116] The cosmetic composition of the present invention has a good feel during use and is therefore suitable for skin care, hair care, and makeup. The cosmetic composition of the present invention can be applied to sprays, emulsions, sheets, powders, and the like.

[0117] Specific uses include, for example, facial cleansers, cleansers, makeup removers, lotions, emulsions, gels, beauty serums, facial masks, face masks, shaving lotions, sunscreens, after-sun lotions, sunscreen preparations, deodorizing lotions, body lotions, hand lotions, foot lotions, lipsticks, lip glosses, lip liners, hair waxes, hair mousses, hair gels, hair oils, hair sprays, hair spray mists, hair milks, leave-in hair creams, leave-in conditioners, foundations, liquid foundations, concealers, blushers, eyeliners, eyebrow pencils, eye shadows, lipsticks, and the like.

[0118] The following matters are disclosed in this specification.

[0119] The Disclosure <1> A solid emulsifier for oil-in-water emulsion, comprising metal oxide particles, wherein the volume average particle size of the metal oxide particles is 0.2 to 0.4 μm, and the specific surface area is 5 to 20 m 2 / g, and the hydrophobicity measured by the following method is 5 to 35.

[0120] <Method for measuring hydrophobicity>

[0121] (1) Add 50 mL of ion-exchanged water to a 100 mL beaker.

[0122] (2) 0.2 g of metal oxide particles as a test sample was added to the beaker of (1), and stirred with a PTFE stirrer (length 30 mm × diameter 8 mm). The stirring speed was adjusted so that when the stirring state in the beaker was observed from the side of the beaker, the bottom of the vortex generated by stirring was higher than the midpoint of the distance from the liquid surface to the bottom of the beaker.

[0123] (3) While continuing to stir, 0.5 mL of methanol was added dropwise using a burette. Stirring was stopped after 30 seconds had passed since the stirring was stopped, and it was determined whether metal oxide particles were visually observed on the liquid surface after 30 seconds had passed since the stirring was stopped.

[0124] (4) Step (3) is repeated until metal oxide particles can no longer be visually confirmed on the liquid surface in step (3).

[0125] (5) Calculate the volume percentage of the volume of the methanol added in (3) and (4) relative to the total volume of the ion-exchanged water in the beaker (50 mL) and the volume (mL) of the methanol added in (3) and (4), and use the value as the hydrophobicity.

[0126] The Disclosure <2> For this disclosure <1> In the solid emulsifier for oil-in-water emulsion, the metal oxide particles are silicon dioxide particles.

[0127] The Disclosure <3> A method for producing an oil-in-water emulsion, wherein an oil phase component is dispersed in an aqueous phase component, and the method comprises:

[0128] Dispersion process, so that the present disclosure <1> or <2> The oil-in-water emulsion is dispersed in an aqueous solvent using a solid emulsifier to obtain an aqueous dispersion; and

[0129] In the emulsification step, the oil phase component is added to the aqueous dispersion while stirring the aqueous dispersion.

[0130] The Disclosure <4> For this disclosure <3> The method for producing an oil-in-water emulsion, wherein the aqueous dispersion contains an alcohol having a water solubility of 500 g / L or more at 20°C, the mass ratio of the alcohol in the aqueous dispersion is 5 to 55 parts by mass relative to 100 parts by mass of water, and the pH of the aqueous dispersion at 25°C is 7 to 14.

[0131] The Disclosure <5> A method for producing an oil-in-water emulsion, wherein an oil phase component is dispersed in an aqueous phase component, comprises: a dispersing step, <1> or <2> The oil-in-water emulsion is dispersed in an oil component with a solid emulsifier to obtain an oil dispersion; and an emulsification step of adding the water phase component to the oil dispersion while stirring the oil dispersion.

[0132] The Disclosure <6> It is an oil-in-water emulsion, which comprises the present disclosure <1> or <2> The oil-in-water emulsion uses a solid emulsifier.

[0133] The Disclosure <7> A cosmetic composition comprising the present invention <6> The oil-in-water emulsion.

[0134] Example

[0135] Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to these examples. It should be noted that each measuring method is as follows.

[0136] <Volume Average Particle Size>

[0137] In the following Examples and Comparative Examples, silica particles were used as the surface-untreated metal oxide particles, and the volume average particle diameter of the silica particles was measured using a laser diffraction particle size distribution measuring device (Horiba, Ltd.) or the like. Water, isopropyl alcohol or other solvents were filled in the measuring cell of the laser diffraction particle size distribution measuring device, and ultrasonic waves were applied while adding silica powder little by little until a concentration suitable for measurement was reached. After adjusting to an appropriate concentration, the particle size distribution was measured.

[0138] <BET specific surface area (m 2 / g)>

[0139] The BET specific surface area of the silica particles was measured by the BET method described in JIS 8830:2013 using a gas adsorption specific surface area measuring device (Shimadzu Corporation). The silica particles were weighed in the measuring cell of the surface area measuring device, heated to 200 °C, cooled and heated using liquid nitrogen, and the specific surface area was calculated from the amount of gas generated by nitrogen desorption.

[0140] <Manufacture of solid emulsifier for oil-in-water emulsion>

[0141] (Example 1-1)

[0142] 100 parts by mass of uncoated deflagration method silica particles (trade name “SO-C1”, volume average particle diameter 0.3 μm, specific surface area 16 m 2 / g, manufacturer: Admatechs Co., Ltd.) were surface-treated with 0.75 parts by mass of a silylating agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “SZ-31”, hexamethyldisilazane) to obtain a solid emulsifier (E-1) for oil-in-water emulsion with a hydrophobicity of 35 in Example 1-1.

[0143] The surface treatment with the silylating agent was carried out as follows: the silylating agent was added little by little while stirring the silica powder with a mixer, and then heat treatment was carried out at 130 °C.

[0144] (Example 1-2) to (Example 1-3) and (Comparative Example 1-1) to (Comparative Example 1-2)

[0145] The silica particles and the silylating agent were changed to the amounts shown in Table 1, and otherwise, solid emulsifiers (E-2 to E-3) for oil-in-water emulsion in Examples 2 to 3 and solid emulsifiers (CE-1 to CE-2) for oil-in-water emulsion in Comparative Examples 1 to 2 were obtained in the same manner as in Example 1-1. In addition, the hydrophobicity of the obtained solid emulsifiers for oil-in-water emulsion was measured. The results are shown in Table 1. It should be noted that the unit of the numerical values of the components in Table 1 is “parts by mass”.

[0146] [Table 1]

[0147]

[0148] <Manufacturing of Oil-in-Water Emulsion>

[0149] (Example 2-1)

[0150] 1. Dispersion process

[0151] Into a 300 mL tall beaker, 35.4 g of ionized water and 6.25 g of ethanol were added, and a 10% by mass aqueous solution of sodium hydroxide (0.1417 g) as an aqueous solution of a pH adjuster was added and homogenized. Then, 3.75 g of the solid emulsifier (E-1) for the oil-in-water emulsion obtained in Example 1-1 was added, and the mixture was stirred for 1 minute (rotation speed 8000 rpm) with a homogenizer to prepare an aqueous dispersion.

[0152] 2. Emulsification process

[0153] After the aqueous dispersion was prepared, 25 g of liquid paraffin (manufactured by Sonneborn, trade name "Carnation") as an oily component was added while stirring, and 54.2 g of ionized water as an aqueous solvent as another water-soluble component was added 1 minute later, and 125 g of 1% by mass hydroxyethyl cellulose (manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Hydroxyethyl Cellulose" (4500-6500 mPa·s, 2% by mass aqueous solution, 25° C.) as an aqueous thickener was added 1 minute later. 0.2268 g of a 10% by mass citric acid aqueous solution (manufactured by Tokyo Chemical Industry Co., Ltd.) as a pH adjuster as another water-soluble component was further added while stirring to adjust the pH to 7.0±1.0.

[0154] 3. Degassing and standing

[0155] After the emulsification step, the mixture was degassed and left to stand overnight at 25° C. to prepare an oil-in-water emulsion of Example 2-1.

[0156] (Example 2-2) to (Example 2-8) and (Comparative Example 2-1) to (Comparative Example 2-3)

[0157] The oil-in-water emulsions of Examples 2-2 to 2-8 and Comparative Examples 2-1 to 2-3 were obtained in the same manner as in Example 2-1 except that the solid emulsifier for oil-in-water emulsion, aqueous solvent, pH-adjusting aqueous solution, other water-soluble components, thickener aqueous solution, and oily components were changed to the amounts described in Tables 2 and 4. It should be noted that in Comparative Example 2-3, as the solid emulsifier for oil-in-water emulsion (CE-3), commercially available surface-treated fumed silica particles (manufactured by Evonik, trade name "Aerosil r816", volume average particle size 0.01 μm, specific surface area 170-210 m 2 / g, hydrophobicity 0).

[0158] (Example 2-9)

[0159] 1. Emulsification process

[0160] Into a 300 mL tall beaker, 50 g of liquid paraffin (manufactured by Sonneborn, trade name "Carnation") as an oily component and 7.5 g of the solid emulsifier for the oil-in-water emulsion (E-2) obtained in Example 1-2 were placed, and stirred for 1 minute with a homomixer (rotation speed 8000 rpm), 67.5 g of ionized water was added, and after 1 minute, 125 g of a 1% by mass aqueous solution of hydroxyethyl cellulose (manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Hydroxyethyl Cellulose" (4500-6500 mPa·s, 2% by mass aqueous solution, 25°C)) was added as an aqueous thickener, and stirred for 1 minute.

[0161] 2. Degassing and standing

[0162] After the emulsification step, the mixture was degassed and left to stand overnight at 25° C. to prepare an oil-in-water emulsion of Example 2-9.

[0163] The oil-in-water emulsions of each example and each comparative example were subjected to appearance tests, storage stability tests, and evaluations of feeling during use. The results are shown in Tables 2 to 4.

[0164] In addition, the unit of the numerical value of the component in Tables 2 to 4 is "g".

[0165] <Appearance test>

[0166] 40 mL of the obtained oil-in-water emulsion was placed in a 50 ml screw tube, and the presence or absence of a water phase and an oil phase was confirmed. The evaluation criteria are as follows.

[0167] ○: Only O / W emulsified phase, no separation observed

[0168] ×: Oil phase was observed in addition to the emulsified phase

[0169] <Storage stability test>

[0170] 40 mL of the obtained oil-in-water emulsion was placed in a 50-ml screw tube and stored at 25° C. or 50° C. for 1 month, and then the presence or absence of separation of the oil phase was confirmed. The evaluation criteria are as follows.

[0171] (Evaluation Criteria)

[0172] ○: No oil phase separation

[0173] ×: There is separation of oil phase

[0174] <User experience evaluation>

[0175] The astringency of the skin was evaluated by a panel of 10 experts. The inner side of each judge's forearm was washed with water, and the water was wiped off with a towel. After drying for 15 minutes, 1 g of the obtained oil-in-water emulsion was applied to the inner side of the forearm. The sensory evaluation results on the astringency of the skin were expressed as scores, and the average score was used for evaluation. The astringency when using cosmetics was evaluated on a scale of 1 to 5 by sensory evaluation, and the average score of the 10 people was calculated. The evaluation criteria are as follows.

[0176] 5 points: No astringency, very good feel

[0177] 4 points: No astringency, good feel

[0178] 3 points: Average

[0179] 2 points: Slightly astringent

[0180] 1 point: Strong astringency, poor feel

[0181] [Table 2]

[0182]

[0183] [Table 3]

[0184]

[0185] [Table 4]

[0186]

[0187] In addition, the raw materials other than those described in the above Examples used in Tables 2 to 4 are as follows.

[0188] [Aqueous solvent in aqueous dispersion]

[0189] ・Ethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "Ethanol (99.5)")

[0190] ・Propylene glycol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "propylene glycol")

[0191] ·Dipropylene glycol (manufactured by ADEKA, trade name "DPG-RF")

[0192] 1,3-Butanediol (manufactured by Tokyo Chemical Industry Co., Ltd., trade name "1,3-Butanediol")

[0193] Isopentyl glycol (manufactured by Kuraray, trade name "IPG-S")

[0194] Glycerin (manufactured by Kao Corporation, trade name "Concentrated Glycerin for Cosmetics")

[0195] PEG-8 (manufactured by Sanyo Chemical Industries, Ltd., trade name "PEG-400")

[0196] [pH adjuster in aqueous dispersion]

[0197] Potassium hydroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "potassium hydroxide")

[0198] [Thickeners in other water-soluble ingredients]

[0199] Cellulose nanofiber (manufactured by Nippon Paper Industries, trade name "Cellenpia CS-01C")

[0200] Polyacrylic acid (manufactured by Lubrizol, trade name "Carbopol 980 Polymer")

[0201] Sodium acrylate grafted starch (manufactured by Sanyo Chemical Industries, Ltd., trade name "Sanfresh ST-100")

[0202] [Oily ingredients]

[0203] ·Dimethicone (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KF-96L-2cs")

[0204] · Caprylic / capric triglyceride (manufactured by Nissin Oillio Co., Ltd., trade name "ODO")

[0205] · Glyceryl triethylhexanoate (manufactured by Nissin Oillio Co., Ltd., trade name "TIO")

[0206] Olive oil (manufactured by Nikko Chemical Co., Ltd., trade name "NIKKOL Olive Oil")

[0207] · Cetyl ethylhexanoate (manufactured by Nissin Oillio Co., Ltd., trade name "SALACOS 816")

[0208] In addition, in Tables 2 to 4, the numerical values ​​of the compositions are "g".

[0209] As shown in Tables 2 to 4, the oil-in-water emulsions of the Examples were superior in storage stability, had low astringency, and had good feel during use, compared with the oil-in-water emulsions of the Comparative Examples.

[0210] Industrial Applicability

[0211] The oil-in-water emulsion of the present invention has excellent storage stability, low astringency, and good feeling during use, and can therefore be used in cosmetics and quasi-drugs. In addition, the oil-in-water emulsion of the present invention has excellent storage stability, and can therefore also be suitably used in the fields of coatings, detergents, foods, building materials, papermaking, fibers, ceramics, toiletries / sanitation, and drainage.

Claims

1. A solid emulsifier for oil-in-water emulsion, comprising metal oxide particles, wherein the volume average particle size of the metal oxide particles is 0.2 μm to 0.4 μm and the specific surface area is 5 m 2 / g~20m 2 / g, the hydrophobicity measured by the following method is 5 to 35, <Method for measuring hydrophobicity> (1) Add 50 mL of ion exchange water to a 100 mL beaker; (2) 0.2 g of metal oxide particles as a measurement sample is added to the beaker of (1), and stirred with a PTFE stirring bar having a length of 30 mm and a diameter of 8 mm. The stirring speed is adjusted so that when the stirring state in the beaker is observed from the side of the beaker, the bottom of the vortex generated by the stirring is higher than the midpoint of the distance from the liquid surface to the bottom of the beaker; (3) While continuing to stir, 0.5 mL of methanol was added dropwise using a burette. After 30 seconds from the addition of methanol, stirring was stopped. After 30 seconds from the cessation of stirring, it was determined whether metal oxide particles could be visually confirmed on the liquid surface. (4) repeating step (3) until metal oxide particles can no longer be visually confirmed on the liquid surface in (3); (5) Calculate the percentage of the volume of the methanol added dropwise in (3) and (4) relative to the total volume of the ion-exchanged water in the beaker (50 mL) and the volume (mL) of the methanol added dropwise in (3) and (4), and use the value as the hydrophobicity.

2. The solid emulsifier for oil-in-water emulsion according to claim 1, wherein The metal oxide particles are silicon dioxide particles.

3. A method for producing an oil-in-water emulsion, wherein an oil phase component is dispersed in an aqueous phase component, comprising: a dispersing step of dispersing the solid emulsifier for the oil-in-water emulsion according to claim 1 or 2 in an aqueous solvent to obtain an aqueous dispersion; and In the emulsification step, the oil phase component is added to the aqueous dispersion while stirring the aqueous dispersion.

4. The method for producing an oil-in-water emulsion according to claim 3, wherein: The aqueous dispersion contains an alcohol having a water solubility of 500 g / L or more at 20° C., the mass ratio of the alcohol in the aqueous dispersion is 5 to 55 parts by mass relative to 100 parts by mass of water, and the pH of the aqueous dispersion at 25° C. is 7 to 14.

5. A method for producing an oil-in-water emulsion, wherein an oil phase component is dispersed in an aqueous phase component, comprising: a dispersing step of dispersing the solid emulsifier for the oil-in-water emulsion according to claim 1 or 2 in an oily component to obtain an oily dispersion; and In the emulsification step, the aqueous phase component is added to the oily dispersion while stirring the oily dispersion. 6 . An oil-in-water emulsion comprising the solid emulsifier for oil-in-water emulsion according to claim 1 .

7. A cosmetic composition comprising the oil-in-water emulsion according to claim 6.

Images