Oil-in-water emulsion cosmetics

Abstract

To provide an oil-in-water type emulsified cosmetic that has an excellent ultraviolet ray blocking effect, excellent emulsion stability, is likely to break down as a formulation during application, and has an excellent usability with suppressed frictional feeling during application and tight feeling after application. 【Solution means】An oil-in-water type emulsified cosmetic containing the following components (A), component (B), and component (C), The content of component (A) is 7% by mass or more and 23% by mass or less, The content of component (B) is 0.15% by mass or more and 2% by mass or less, Component (B) is at least one selected from the group consisting of a (sodium acryloyldimethyltaurate / sodium acrylate) copolymer and a (acryloyldimethyltaurine ammonium / behenyl methacrylate-25) cross-polymer, The mass ratio [(B) / (C)] of the content of component (B) to component (C) is 0.5 or more and 1 or less, An oil-in-water type emulsified cosmetic. (A) Hydrophobically treated fine particle metal oxide having an average primary particle diameter of less than 100 nm (B) A water phase thickener containing a structure derived from 2-acrylamido-2-methylpropane sulfonic acid (C) Amphoteric surfactant

Description

Technical Field

[0001] The present invention relates to an oil-in-water type emulsified cosmetic having an excellent ultraviolet ray blocking effect.

Background Art

[0002] In recent years, as the importance of protection from ultraviolet rays in daily life has increased, the need for sunscreen cosmetics has also been expanding. From such market needs, oil-in-water type emulsified sunscreen cosmetics that are easy to use in combination with a refreshing feeling have been developed.

[0003] In these oil-in-water type emulsified cosmetics, in order to enhance the ultraviolet ray blocking effect, ultraviolet absorbers and ultraviolet scattering agents are used. Particularly, as the ultraviolet scattering agent, metal oxide powders such as zinc oxide and titanium oxide are used. However, when a metal oxide powder is blended into an oil-in-water type emulsified cosmetic, there are problems such as a poor feeling in use and insufficient stability of the metal oxide powder in the oil-in-water type emulsified cosmetic. In order to improve such problems, for example, in Patent Document 1, an oil-in-water type emulsified composition that stably contains a hydrophobized powder, is excellent in the stability of the emulsion system during high-temperature storage and when a shearing force is applied, and is excellent in the feeling in use such as freshness, has a carbon number of an alkyl group or an alkenyl group within a predetermined range, and an average added molar number of ethylene oxide within a predetermined range. A polyoxyethylene alkyl ether or polyoxyethylene alkenyl ether, a phospholipid, a hydrophobized powder, and water are contained, and an oil-in-water type emulsified composition in which the content mass ratio of the polyoxyethylene alkyl ether or polyoxyethylene alkenyl ether to the phospholipid is within a predetermined range is disclosed. Patent Document 2 discloses an oil-in-water emulsion cosmetic composition that has excellent UV protection, good stability over time, and excellent abrasion resistance. The composition contains a liquid oil containing an oil-soluble organic UV absorber, a salt-resistant water-soluble polymer, and hydrophobically treated fine metal oxide powder. The liquid oil contains 40% by mass or more of a component with an IOB value of 0.10 or higher, the liquid oil is contained in an amount of 3% by mass or more and 30% by mass or less of the total amount of the cosmetic composition, and the mass ratio of the hydrophobically treated fine metal oxide powder to the liquid oil is 0.4 or more and 1.0 or less. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2018-108994 [Patent Document 2] Japanese Patent Publication No. 2019-94280 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, when incorporating a large amount of metal oxide powder into oil-in-water emulsion cosmetics to enhance UV protection, the emulsion stability is still insufficient. Furthermore, the formulation may not easily break down during application, and a feeling of friction may be experienced. In addition, a feeling of tightness may occur after application. The present invention aims to provide an oil-in-water emulsion cosmetic that has excellent UV protection, excellent emulsification stability, is easily broken down as a formulation during application, and has a superior feel with reduced friction during application and tightness after application. [Means for solving the problem]

[0006] The inventors have discovered that by using hydrophobized fine particle metal oxides having an average primary particle size within a predetermined range, an aqueous phase thickener having a specific structure, and an amphoteric surfactant, and by setting the content of hydrophobized fine particle metal oxides within a predetermined range, it is possible to obtain an oil-in-water emulsion cosmetic that has excellent UV protection ability, high emulsion stability, is easily broken down as a formulation during application, and has a superior feel with reduced friction during application and tightness after application.

[0007] In other words, the present invention is an oil-in-water emulsion cosmetic containing the following components (A), (B), and (C), Component (A): Hydrophobized metal oxide fine particles with an average primary particle diameter of less than 100 nm. Component (B): Aqueous phase thickener containing a structure derived from 2-acrylamido-2-methylpropanesulfonic acid Ingredient (C): Amphoteric surfactant This is an oil-in-water emulsion cosmetic having an ingredient (A) content of 7% by mass or more and 30% by mass or less. [Effects of the Invention]

[0008] The present invention provides an oil-in-water emulsion cosmetic that has excellent UV protection, excellent emulsification stability, is easily broken down as a formulation during application, and has a superior feel with reduced friction during application and tightness after application. [Modes for carrying out the invention]

[0009] [Oil-in-water emulsion cosmetic] The oil-in-water emulsion cosmetic of the present invention (hereinafter also referred to as "emulsified cosmetic") is an oil-in-water emulsion cosmetic containing the following components (A), (B), and (C), Component (A): Hydrophobized metal oxide fine particles with an average primary particle diameter of less than 100 nm. Component (B): Aqueous phase thickener containing a structure derived from 2-acrylamido-2-methylpropanesulfonic acid Ingredient (C): Amphoteric surfactant The content of component (A) is between 7% by mass and 30% by mass. Furthermore, in this invention, "hydrophobically treated fine metal oxide particles" refers to fine metal oxide particles whose surface has been subjected to a hydrophobic treatment.

[0010] The oil-in-water emulsion cosmetic of the present invention has excellent UV protection, excellent emulsion stability, is easily broken down as a formulation during application, and provides a comfortable feel with reduced friction during application and tightness after application. The reason for this is not entirely clear, but it is thought to be as follows. The fine metal oxide particles contained in the emulsified cosmetic of the present invention have an average primary particle diameter of less than 100 nm and their surfaces are hydrophobically treated. Furthermore, by using an aqueous phase thickener containing a structure derived from 2-acrylamido-2-methylpropanesulfonic acid and an amphoteric surfactant as thickeners to thicken the continuous aqueous phase, it is believed that even with a high content of fine metal oxide particles in an oil-in-water emulsified cosmetic, the fine metal oxide particles can be stably present in the oil phase. As a result, emulsification stability is improved, ultraviolet rays are efficiently scattered, and the UV protection ability can be enhanced. Moreover, it is believed that the formulation is less likely to break down during application, and friction during application and tightness after application can be suppressed.

[0011] <Component (A): Hydrophobized metal oxide fine particles with an average primary particle diameter of less than 100 nm> The oil-in-water emulsion cosmetic of the present invention contains hydrophobized fine particle metal oxide with an average primary particle diameter of less than 100 nm as component (A). The metal oxide of component (A) is preferably one or more selected from the group consisting of zinc oxide, titanium oxide, and cerium oxide, from the viewpoint of scattering ultraviolet rays and enhancing the ultraviolet protection effect, and more preferably one or more selected from the group consisting of zinc oxide and titanium oxide. Furthermore, these fine particle metal oxides can contain metals with a valent or higher valency, and metals or oxides such as iron, zirconium, calcium, manganese, magnesium, and yttrium can be included in the metal oxide, either alone or in appropriate combinations of two or more.

[0012] The average primary particle size of component (A) is less than 100 nm, preferably 90 nm or less, more preferably 70 nm or less, even more preferably 50 nm or less, even more preferably 40 nm or less, even more preferably 30 nm or less, and preferably 1 nm or more, more preferably 5 nm or more, even more preferably 10 nm or more, from the viewpoint of enhancing the UV protection effect and improving emulsification stability. More specifically, the average primary particle size of component (A) is preferably 1 to 90 nm, more preferably 1 to 70 nm, even more preferably 1 to 50 nm, even more preferably 5 to 50 nm, even more preferably 10 to 50 nm, even more preferably 10 to 40 nm, and even more preferably 10 to 30 nm, from the viewpoint of enhancing the UV protection effect and improving emulsification stability.

[0013] The shape of component (A) can be, for example, spherical, flaky, rod-shaped, fusiform, needle-shaped, or irregularly shaped, but any shape can be used as long as the average primary particle diameter is within the aforementioned range. The average primary particle diameter of component (A) in this invention can be determined from an observation image obtained by a transmission electron microscope (TEM). Specifically, it is determined by observing the particle with a TEM at a magnification of 50,000x, measuring the maximum minor diameter of 300 primary particles in the observation image, and calculating the number average value. Here, the maximum minor diameter refers to the longest minor diameter among the minor diameters perpendicular to the major diameter, if component (A) has a shape other than a flake. If component (A) has a flake shape, it is determined by measuring the thickness of 300 primary particles in the observation image observed under the same conditions as above and calculating the number average value. Specifically, it is measured by the method described in the examples.

[0014] Hydrophobic treatments for component (A) include silicone treatment; alkylalkoxysilane treatment; fatty acid treatment; fluorine-containing compound treatment with perfluoroalkyl phosphate esters, perfluoroalcohols, etc.; amino acid treatment with N-acyl glutamic acid, etc.; lecithin treatment; metal soap treatment; alkyl phosphate ester treatment; and ASI treatment with N-acyl amino acid metal salts (sodium lauroyl aspartate), zinc chloride, and alkoxytitanium alkylate (isopropyl titanium triisostearate). These surface treatments may be applied individually or in combination of two or more types. Among these, the hydrophobic treatment of component (A) is preferably one or more selected from the group consisting of silicone treatment, alkylalkoxysilane treatment, and fatty acid treatment, from the viewpoint of increasing the content of fine metal oxide particles in the oil-in-water emulsion cosmetic and improving the UV protection effect, improving emulsion stability and the ease with which the formulation breaks down during application, and suppressing the feeling of friction during application and the feeling of tightness after application.

[0015] Examples of surface treatment agents used in silicone treatment include various silicone oils such as methylpolysiloxane, dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, methylcyclopolysiloxane, dodecamethylcyclohexasiloxane, tetradecamethylhexasiloxane, dimethylsiloxane / methyl(polyoxyethylene)siloxane / methyl(polyoxypropylene)siloxane copolymer, dimethylsiloxane / methyl(polyoxyethylene)siloxane copolymer, dimethylsiloxane / methyl(polyoxypropylene)siloxane copolymer, dimethylsiloxane / methylcetyloxysiloxane copolymer, dimethylsiloxane / methylstearoxysiloxane copolymer, and (alkyl acrylate / dimethicone) copolymer. Among these, methylhydrogenpolysiloxane and dimethylpolysiloxane are preferred from the viewpoint of improving the dispersibility of component (A) in emulsified cosmetics, improving UV protection effect, emulsification stability, and the ease with which the formulation breaks down during application, as well as suppressing friction during application and tightness after application.

[0016] The surface treatment agent used for the alkylalkoxysilane treatment preferably has a linear or branched alkyl group having 6 to 20 carbon atoms from the viewpoints of enhancing the dispersibility of component (A) in the emulsified cosmetic, improving the UV protection effect, emulsification stability, and the tendency of the formulation to collapse during application, and suppressing the frictional feeling during application and the tight feeling after application. Octyltriethoxysilane and octyltrimethoxysilane are more preferable.

[0017] Examples of the surface treatment agent used for the fatty acid treatment include linear or branched higher fatty acids having 12 to 22 carbon atoms. Among these, from the viewpoints of improving the UV protection effect, emulsification stability, and the tendency of the formulation to collapse during application, and suppressing the frictional feeling during application and the tight feeling after application, linear or branched higher fatty acids having 14 to 22 carbon atoms are preferable, linear or branched higher fatty acids having 16 to 20 carbon atoms are more preferable, and stearic acid and isostearic acid are even more preferable. The above-mentioned surface treatment agents may be used alone or in combination of two or more.

[0018] Examples of commercially available products of hydrophobically treated fine particle zinc oxide include FINEX series (manufactured by Sakai Chemical Industry Co., Ltd.), MZ series, MZY series (manufactured by Tayca Corporation), etc. Examples of commercially available products of hydrophobically treated fine particle titanium oxide include STR series (manufactured by Sakai Chemical Industry Co., Ltd.), TTO-55 series, TTO-51 series (manufactured by Ishihara Sangyo Co., Ltd.), MT series, MTY series (manufactured by Tayca Corporation), etc.

[0019] From the viewpoints of enhancing the dispersibility of component (A) in the emulsified cosmetic, improving the UV protection effect, emulsification stability, and the tendency of the formulation to collapse during application, and suppressing the frictional feeling during application and the tight feeling after application, the treatment amount of the hydrophobization treatment in component (A) is preferably 0.1% by mass or more with respect to component (A), and is preferably 40% by mass or less, more preferably 30% by mass or less. In this invention, the mass and average primary particle diameter of component (A) refer to the mass and average primary particle diameter including the surface treatment agent.

[0020] The content of component (A) in the emulsified cosmetic of the present invention is 7% by mass or more, preferably 9% by mass or more, more preferably 10% by mass or more, and even more preferably 13% by mass or more, from the viewpoint of enhancing the UV protection effect, and from the viewpoint of improving emulsification stability and the ease with which the formulation collapses during application, and from the viewpoint of suppressing friction during application and tightness after application, it is 30% by mass or less, preferably 27% by mass or less, more preferably 25% by mass or less, even more preferably 23% by mass or less, and even more preferably 20% by mass or less. More specifically, from the viewpoint of enhancing the UV protection effect, improving emulsification stability and the ease with which the formulation collapses during application, and from the viewpoint of suppressing friction during application and tightness after application, it is preferably 9 to 27% by mass, more preferably 10 to 25% by mass, even more preferably 10 to 23% by mass, and even more preferably 13 to 20% by mass.

[0021] From the viewpoint of transparency when applied to the skin, component (A) preferably contains hydrophobized fine-particle zinc oxide. When component (A) contains hydrophobized fine-particle zinc oxide, the content of hydrophobized fine-particle zinc oxide in component (A) is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more, from the same viewpoint as above. From the viewpoint of UV protection effect, component (A) preferably contains hydrophobized titanium dioxide microparticles. When component (A) contains hydrophobized titanium dioxide microparticles, the content of hydrophobized titanium dioxide microparticles in component (A) is preferably 50% by mass or more, more preferably 55% by mass or more, even more preferably 60% by mass or more, and even more preferably 65% ​​by mass or more, from the same viewpoint as above.

[0022] <Component (B): Aqueous phase thickener containing a structure derived from 2-acrylamido-2-methylpropanesulfonic acid> The oil-in-water emulsion cosmetic of the present invention contains an aqueous phase thickener as component (B) that includes a structure derived from 2-acrylamido-2-methylpropanesulfonic acid (acryloyldimethyltauric acid) (hereinafter also referred to as "acryloyldimethyltauric acid" or "AMPS"). Component (B) is not particularly limited as long as it contains a structure derived from 2-acrylamido-2-methylpropanesulfonic acid (acryloyldimethyltauric acid) and has the effect of thickening the continuous aqueous phase. However, from the viewpoint of enhancing the UV protection effect, improving emulsification stability and the ease with which the formulation breaks down during application, and suppressing friction during application and tightness after application, it is preferably a water-soluble polymer containing constituent units derived from acryloyldimethyltauric acid. Examples of water-soluble polymers containing constituent units derived from acryloyldimethyltauric acid include homopolymers of acryloyldimethyltauric acid and copolymers containing constituent units derived from acryloyldimethyltauric acid, with copolymers containing constituent units derived from acryloyldimethyltauric acid (AMPS) being preferred.

[0023] Examples of copolymers containing AMPS-derived structural units include (AMPS / acrylic acid) copolymers, (AMPS / acrylamide) copolymers, (AMPS / acrylic acid / acrylamide) copolymers, (AMPS / dimethylacrylamide) copolymers, (AMPS / hydroxyethyl acrylate) copolymers, (AMPS / vinylpyrrolidone) copolymers, (AMPS / vinylformamide) copolymers, (AMPS / polyoxyethylene alkyl ester of methacrylic acid (average number of moles of ethylene oxide added: 10-30)) copolymers, and salts thereof. More specifically, examples include (sodium acryloyldimethyltaurate / hydroxyethyl acrylate) copolymer, (sodium acryloyldimethyltaurate / sodium acrylate) copolymer, (acryloyldimethyltaurate / acrylic acid / dimethylacrylamide) crosspolymer, (ammonium acryloyldimethyltaurate / vinylpyrrolidone) copolymer, (sodium acryloyldimethyltaurate / acrylic acid / acrylamide / sodium acrylate) copolymer, (ammonium acryloyldimethyltaurate / dimethylacrylamide / lauryl methacrylate / laureth-4 methacrylate) crosspolymer, (ammonium acryloyldimethyltaurate / beheneth-25 methacrylate) crosspolymer, and (ammonium acryloyldimethyltaurate / steareth-25 methacrylate) crosspolymer. Among these, copolymers containing AMPS-derived structural units are preferred from the viewpoint of enhancing UV protection, improving emulsification stability and the ease with which the formulation breaks down during application, and suppressing friction during application and tightness after application, by further containing structural units derived from acrylic monomers other than AMPS, such as acrylic acid, acrylamide, dimethylacrylamide, alkyl acrylate, alkyl methacrylate, hydroxyalkyl acrylate, and polyoxyethylene alkyl methacrylic acid (average number of moles of ethylene oxide added: 10-30). These acrylic monomers may be used individually or in combination of two or more.

[0024] Commercially available products containing ingredient (B) include: "SIMULGEL EG" ((Sodium Acryloyldimethyltaurate / Sodium Acrylate) Copolymer, Isohexadecane, Polysorbate 80, Water), "SEPIMAX ZEN" ((Ammonium Acryloyldimethyltaurate / Dimethylacrylamide / Lauryl Methacrylate / Laureth-4 Methacrylate) Crosspolymer), "SEPINOV EMT 10" ((Sodium Acryloyldimethyltaurate / Hydroxyethyl Acrylate) Copolymer), "SIMULGEL NS" ((Sodium Acryloyldimethyltaurate / Hydroxyethyl Acrylate) Copolymer, Squalane, Polysorbate 60, Water), "SIMULGEL FL" ((Sodium Acryloyldimethyltaurate / Hydroxyethyl Acrylate) Copolymer, Isohexadecane, Polysorbate 60, Water), and "SEPIPLUS Examples include "S" ((Sodium acryloyldimethyltaurate / hydroxyethyl acrylate) copolymer, polyisobutene, PEG-7 trimethylolpropane coconut oil alkyl ether, water), "SEPIPLUS 400" ((Sodium acryloyldimethyltaurate / acrylic acid / acrylamide / sodium acrylate) copolymer, polyisobutene, polysorbate 20, water) (all manufactured by SEPPIC); "Aristoflex AVC" ((Ammonium acryloyldimethyltaurate / vinylpyrrolidone) copolymer), "Aristoflex HMB" ((Ammonium acryloyldimethyltaurate / beheneth-25 methacrylate) crosspolymer), and "Aristoflex HMS" ((Ammonium acryloyldimethyltaurate / steareth-25 methacrylate) crosspolymer) (all manufactured by Clariant).

[0025] Among these, component (B) is preferably a copolymer containing structural units derived from AMPS, more preferably a copolymer containing structural units derived from AMPS and structural units derived from acrylic monomers, even more preferably one or more selected from the group consisting of (sodium acryloyldimethyltaurate / sodium acrylate) copolymer, (ammonium acryloyldimethyltaurate / beheneth-25 methacrylate) crosspolymer, and (ammonium acryloyldimethyltaurate / dimethylacrylamide / lauryl methacrylate / laureth-4 methacrylate) crosspolymer, and even more preferably (sodium acryloyldimethyltaurate / sodium acrylate) copolymer.

[0026] The content of component (B) in the emulsified cosmetic of the present invention is preferably 0.1% by mass or more, more preferably 0.15% by mass or more, even more preferably 0.2% by mass or more, and even more preferably 0.25% by mass or more, from the viewpoint of enhancing the UV protection effect and improving emulsification stability, and from the viewpoint of improving the ease with which the formulation breaks down during application and suppressing the feeling of friction during application, it is preferably 3% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less, and even more preferably 0.5% by mass or less. More specifically, it is preferably 0.1 to 3% by mass, more preferably 0.15 to 2% by mass, even more preferably 0.2 to 1% by mass, and even more preferably 0.25 to 0.5% by mass.

[0027] The mass ratio of component (A) to component (B) in the emulsified cosmetic composition of the present invention [(A) / (B)] is preferably 10 or more, more preferably 15 or more, even more preferably 20 or more, and even more preferably 30 or more, from the viewpoint of improving the ease with which the formulation breaks down during application and suppressing the feeling of friction during application, and from the viewpoint of enhancing the UV protection effect and improving emulsification stability, it is preferably 90 or less, more preferably 80 or less, even more preferably 70 or less, and even more preferably 50 or less. More specifically, it is preferably 10 to 90, more preferably 15 to 80, even more preferably 20 to 70, and even more preferably 30 to 50.

[0028] <Ingredients (C): Amphoteric surfactant> The oil-in-water emulsion cosmetic composition of the present invention contains an amphoteric surfactant as component (C). Examples of amphoteric surfactants include betaine-type surfactants, amine oxide-type surfactants, and amino acid-type surfactants. Among these, betaine-type surfactants are preferred from the viewpoint of enhancing UV protection, improving emulsification stability and the ease with which the formulation breaks down during application, and suppressing friction during application and tightness after application. Examples of amphoteric surfactants include carboxybetaine types such as alkyldimethylaminoacetic acid betaine and fatty acid amidopropyl betaine; sulfobetaine types such as alkyl sulfobetaine and alkyl hydroxysulfobetaine; imidazoline betaine types such as alkylcarboxymethylhydroxyethylimidazolinium betaine; and phosphobetaine types such as phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and laurylhydroxyphosphobetaine. Among these, phosphobetaine-type amphoteric surfactants are preferred from the viewpoint of enhancing UV protection, improving emulsification stability and the ease with which the formulation breaks down during application, and suppressing friction during application and tightness after application. Lecithin containing phospholipids such as phosphatidylcholine and phosphatidylethanolamine, or hydrogenated lecithin which is a hydrogenated form of said lecithin, are more preferred, and hydrogenated lecithin is even more preferred.

[0029] Hydrogenated lecithin is a hydrogenated form of lecithin, which is a natural product extracted or purified from plants or animals, or a chemically synthesized product. As for natural products, hydrogenated soy lecithin and hydrogenated egg yolk lecithin, which are extracts or purified products from soybeans or egg yolks, are preferred from the viewpoint of reducing the burden on the skin and from the viewpoint of availability, and hydrogenated soy lecithin is more preferred.

[0030] As component (C), hydrogenated lecithin is preferably one that contains phosphatidylcholine, from the viewpoint of enhancing the UV protection effect, improving emulsification stability and the ease with which the formulation breaks down during application, and suppressing friction during application and tightness after application. The phosphatidylcholine content in hydrogenated lecithin is preferably 50% by mass or more, more preferably 55% by mass or more, even more preferably 60% by mass or more, and even more preferably 65% ​​by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, and even more preferably 80% by mass or less. More specifically, it is preferably 50-95% by mass, more preferably 55-90% by mass, even more preferably 60-85% by mass, and even more preferably 65-80% by mass. The phosphatidylcholine content in hydrogenated lecithin can be analyzed using methods such as thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), and IatroScan (manufactured by Yatron). For example, one method involves spotting an organic solvent containing hydrogenated lecithin, as described in Japanese Patent Application Publication No. 2001-186898, onto a TLC plate, developing it with chloroform:methanol:acetic acid = 65:25:10, spraying with 50% by mass sulfuric acid ethanol, heating, and then analyzing the hydrogenated lecithin with a densitometer.

[0031] Examples of commercially available products containing ingredient (C) include "Phospholipid PCSH70" (hydrogenated soy lecithin (phosphatidylcholine content: approximately 70% by mass); manufactured by Nippon Seika Co., Ltd.), "Cortsome NC-21" (hydrogenated soy lecithin; manufactured by NOF Corporation), "Resinol S-10E", and "Resinol S-10EX" (hydrogenated soy lecithin; manufactured by Nikko Chemicals Co., Ltd.).

[0032] The content of component (C) in the emulsified cosmetic of the present invention is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more, from the viewpoint of enhancing the UV protection effect and improving emulsification stability, and preferably 3% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less, and even more preferably 0.7% by mass or less, from the viewpoint of improving the ease with which the formulation breaks down during application and suppressing the feeling of friction during application and the feeling of tightness after application. More specifically, it is preferably 0.1 to 3% by mass, more preferably 0.2 to 2% by mass, even more preferably 0.3 to 1% by mass, and even more preferably 0.3 to 0.7% by mass.

[0033] The mass ratio of component (A) to component (C) in the emulsified cosmetic composition of the present invention [(A) / (C)] is preferably 5 or more, more preferably 7.5 or more, even more preferably 10 or more, and even more preferably 20 or more, from the viewpoint of improving the ease with which the formulation breaks down during application and suppressing the feeling of friction during application and the feeling of tightness after application, and from the viewpoint of enhancing the UV protection effect and improving emulsification stability, it is preferably 80 or less, more preferably 75 or less, even more preferably 70 or less, even more preferably 50 or less, and even more preferably 40 or less. More specifically, it is preferably 5 to 80, more preferably 7.5 to 75, even more preferably 10 to 70, even more preferably 20 to 50, and even more preferably 20 to 40.

[0034] The mass ratio of component (B) to component (C) in the emulsified cosmetic composition of the present invention [(B) / (C)] is preferably 0.3 or higher, more preferably 0.5 or higher, and even more preferably 0.7 or higher, from the viewpoint of improving emulsification stability, and from the viewpoint of improving the ease with which the formulation collapses during application and suppressing the feeling of friction during application, it is preferably 3 or lower, more preferably 2 or lower, and even more preferably 1 or lower. More specifically, it is preferably 0.3 to 3, more preferably 0.5 to 2, and even more preferably 0.7 to 1.

[0035] The oil-in-water emulsion cosmetic composition of the present invention may contain, in addition to components (A), (B), and (C), optional components used depending on the application of the cosmetic composition, as long as they do not impair the effects of the present invention. Examples of such optional components other than components (A), (B), and (C) include ultraviolet absorbers, oils, surfactants, water-soluble polymers, neutralizing agents, pH adjusters, bactericides, anti-inflammatory agents, preservatives, colorants, chelating agents, whitening agents, antiperspirants, antioxidants, fragrances, and the like.

[0036] <Ingredient (D): UV absorber> The oil-in-water emulsion cosmetic composition of the present invention may contain an ultraviolet absorber as component (D) to the extent that it does not impair the effects of the present invention. The ultraviolet absorber may be one or more organic ultraviolet absorbers selected from the group consisting of liquid organic ultraviolet absorbers and solid organic ultraviolet absorbers. In this specification, "liquid" means a state in which a substance has fluidity under 1 atmosphere and 25°C, that is, a state under temperature conditions above its melting point (or, in the case of amorphous substances that do not have a melting point, a state under temperature conditions above its melting point). "Solid" means a state in which a substance does not have fluidity under 1 atmosphere and 25°C, that is, a state under temperature conditions below its melting point (or, in the case of amorphous substances that do not have a melting point, a state under temperature conditions below its melting point).

[0037] Examples of liquid organic ultraviolet absorbers include 2-ethylhexyl paramethoxycinnamate, 2-ethoxyethyl paramethoxycinnamate, isopropyl paramethoxycinnamate / diisopropyl cinnamic acid ester mixture, methylbis(trimethylsiloxy)silylisopentyl trimethoxycinnamate, amyl paradimethylaminobutyric acid benzoate, 2-ethylhexyl paradimethylaminobutyric acid benzoate, ethylene glycol salicylate, 2-ethylhexyl salicylate, benzyl salicylate, homomenthyl salicylate, octocrylene, and dimethicone diethyl benzalmalonate.

[0038] Examples of solid organic ultraviolet absorbers include 2-(4-diethylamino-2-hydroxybenzoyl)hexyl benzoate, 2,4-bis{[4-(2-ethylhexyloxy)-2-hydroxy]phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine, 4-tert-butyl-4'-methoxydibenzoylmethane, and 2-ethylhexyl dimethoxybenzylidene dioxoimidazolidinepropionate.

[0039] Commercially available UV absorbers include, for example, "UVINUL MC80" (2-ethylhexyl paramethoxycinnamate), "UVINUL A PLUS" (2-(4-diethylamino-2-hydroxybenzoyl)hexyl benzoate), "TINOSORB S" (2,4-bis{[4-(2-ethylhexyloxy)-2-hydroxy]phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine), "UVINUL T-150" (2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine) (all manufactured by BASF); "Soft Shade DH" (2-ethylhexyl dimethoxybenzylidene dioxoimidazolidinepropionate) (manufactured by Ajinomoto Co., Inc.); "PARSOL 1789" (4-tert-butyl-4'-methoxydibenzoylmethane), PARSOL SLX (Polysilicone-15 (Dimethicone diethyl benzalmalonate)) (manufactured by DSM) is one example.

[0040] From the viewpoint of reducing the burden on the skin, the content of component (D) in the emulsified cosmetic composition of the present invention is preferably less than 3% by mass, more preferably less than 2% by mass, even more preferably less than 1% by mass, even more preferably less than 0.5% by mass, and even more preferably 0% by mass, i.e., component (D) is not included. Even when the content of component (D) is within the aforementioned range, the emulsified cosmetic of the present invention exhibits excellent UV protection, superior emulsification stability, good ease of breakdown during application, and a superior feel with reduced friction during application and tightness after application. From this viewpoint, the emulsified cosmetic of the present invention can be applied to non-chemical type sunscreen cosmetics that do not contain organic UV absorbers, which have recently attracted attention as skin-friendly cosmetics.

[0041] <Ingredient (E): Other oils besides ingredient (D)> From the viewpoint of incorporating component (A) and improving emulsification stability, the oil-in-water emulsion cosmetic composition of the present invention preferably further contains other oils other than component (D) as component (E). Component (E) is preferably a non-volatile oil, and examples include ester oils, silicone oils, hydrocarbon oils, higher alcohols, and higher fatty acids. The aforementioned non-volatile oil may be liquid or solid at 25°C, but it is preferable that it includes a liquid at 25°C. The definitions of "liquid" and "solid" are as described above. In this specification, "non-volatile" means that the evaporation rate at 25°C for 6 hours, as measured by the following method, is less than 20%. Measurement method: Place a 90mm diameter filter paper in a 120mm diameter glass petri dish, place 1g of sample on the filter paper, and store in a 65% RH room (25°C) for 6 hours. Measure the mass of the sample before and after storage, and calculate the evaporation amount using the following formula. Evaporation rate (%) = (Mass of sample before storage - Mass of sample after storage) / Mass of sample before storage × 100

[0042] Examples of non-volatile liquid ester oils include one or more selected from the group consisting of isononyl isononanoate, isotridecyl isononanoate, isopropyl myristate, isocetyl myristate, octyldodecyl myristate, isopropyl palmitate, ethylhexyl palmitate, 2-hexyldecyl palmitate, glyceryl tri-2-ethylhexanoate, di-2-ethylhexyl sebacate, diisopropyl sebacate, caprylic / capric triglyceride, diisostearyl malate, diethylene glycol dicaprate, neopentyl glycol dicaprate, neopentyl glycol di-2-ethylhexanoate, and alkyl benzoates such as alkyl benzoates (C12-15).

[0043] Among the above, the non-volatile liquid ester oil is preferably one or more selected from the group consisting of a monoester of a branched fatty acid having 8 to 18 carbon atoms and a branched alcohol having 2 to 22 carbon atoms, a triester of a branched fatty acid having 6 to 18 carbon atoms and glycerin, a diester of a dicarboxylic acid having 2 to 18 carbon atoms and a branched alcohol having 2 to 18 carbon atoms, a diester of a fatty acid having 6 to 18 carbon atoms and a branched dialcohol having 2 to 10 carbon atoms, and alkyl benzoate (C12-15) (for example, "Finsolv TN" (manufactured by Innospec Active Chemicals LLC)), more preferably a monoester of a branched fatty acid having 8 to 18 carbon atoms and a branched alcohol having 2 to 22 carbon atoms, and even more preferably one or more selected from the group consisting of isononyl isononanoate and isotridecyl isononanoate.

[0044] The non-volatile liquid silicone oil is preferably dimethylpolysiloxane, and more preferably has a kinematic viscosity of 20 mm at 25°C, from the viewpoint of incorporating component (A) and improving emulsification stability. 2 It is a dimethylpolysiloxane with a saturation level of / s or less. The kinematic viscosity of the silicone oil at 25°C can be measured using an Ubbelohde viscometer in accordance with ASTM D 445-46T or JIS Z 8803.

[0045] Examples of non-volatile liquid hydrocarbon oils include liquid paraffin, hydrogenated polyisobutene (liquid isoparaffin, heavy liquid isoparaffin), cycloparaffin, liquid ozokerite, squalene, squalane, pristane, α-olefin oligomer, polybutene, isohexadecane, and the like.

[0046] Examples of non-volatile liquid higher alcohols include higher alcohols having 12 to 24 carbon atoms, specifically oleyl alcohol, 2-decyltetradecinol, dodecanol, isostearyl alcohol, and 2-octyldodecanol. Examples of non-volatile liquid higher fatty acids include fatty acids with 12 to 22 carbon atoms, specifically oleic acid, isostearic acid, linoleic acid, and linolenic acid.

[0047] Furthermore, from the viewpoint of improving emulsification stability, the oil-in-water emulsion cosmetic composition of the present invention preferably further contains a non-volatile oil that is solid at 25°C as component (E). Examples of non-volatile oils that are solid at 25°C include solid ester oils such as glyceryl monostearate and glyceryl monomyristate; solid silicone oils such as alkyl-modified silicones; solid hydrocarbon oils such as petrolatum; solid higher alcohols such as cetyl alcohol, stearyl alcohol, and behenyl alcohol; and solid higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, 12-hydroxystearic acid, and lanolin fatty acid.

[0048] Among these, component (E) is preferably one or more selected from the group consisting of ester oils, silicone oils, and higher alcohols, from the viewpoint of incorporating component (A) and improving emulsification stability. The above-mentioned oils may be contained individually or in combination of two or more types.

[0049] The content of component (E) in the emulsified cosmetic composition of the present invention is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, even more preferably 17% by mass or more, and preferably 30% by mass or less, more preferably 27% by mass or less, even more preferably 25% by mass or less, from the viewpoint of incorporating component (A) and improving emulsification stability. More specifically, it is preferably 5 to 30% by mass, more preferably 10 to 27% by mass, even more preferably 15 to 25% by mass, and even more preferably 17 to 25% by mass.

[0050] <Component (F): Water-soluble polymer> From the viewpoint of obtaining good emulsification stability, the oil-in-water cosmetic composition of the present invention preferably further contains a water-soluble polymer having a thickening effect other than component (B) as component (F). As for ingredient (F), there are no restrictions as long as it is used in ordinary cosmetics, and any natural polymer, semi-synthetic polymer, or synthetic polymer other than ingredient (B) can be used.

[0051] Examples of natural polymers include xanthan gum, carrageenan, and alginic acid. Among these, xanthan gum is preferred from the viewpoint of obtaining good emulsification stability. Examples of semi-synthetic polymers include modified polysaccharides such as hydroxycellulose, hydroxypropylcellulose, sodium carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, and cationized cellulose. Examples of synthetic polymers other than component (B) include acrylic polymers other than component (B), such as carbomer (cross-linked polyacrylic acid), polyacrylic acid, sodium polyacrylate, (acrylic acid / alkyl methacrylate) copolymer, polyacrylamide, (acrylamide / ammonium acrylate) copolymer; polyvinylpyrrolidone, polyvinyl alcohol, and cationized polyvinylpyrrolidone.

[0052] Commercially available carbomer products include "Carbopol 910," "Carbopol 934," "Carbopol 940," "Carbopol 941," "Carbopol 980," and "Carbopol 981" (all manufactured by Lubrizol Advanced Materials). Commercially available (acrylic acid / alkyl methacrylate) copolymers include "Carbopol 1382," "Carbopol ETD2020," "PEMULEN TR-1," and "PEMULEN TR-2" (all manufactured by Lubrizol Advanced Materials). Examples of commercially available polyacrylamide products include "SEPIGEL305" (manufactured by SEPPIC).

[0053] The content of component (F) in the emulsified cosmetic composition of the present invention is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, from the viewpoint of obtaining good emulsification stability, and preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, from the viewpoint of improving the feel of use. More specifically, it is preferably 0.01 to 5% by mass, more preferably 0.05 to 3% by mass, and even more preferably 0.1 to 1% by mass.

[0054] (aqueous medium) The oil-in-water emulsion cosmetic composition of the present invention contains at least water as an aqueous medium. Examples of aqueous media other than water include saturated monohydric alcohols having 1 to 3 carbon atoms, such as ethanol and isopropyl alcohol; and polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (average molecular weight less than 650), propylene glycol, dipropylene glycol, polypropylene glycol (average molecular weight less than 650), isoprene glycol, 1,3-butylene glycol, glycerin, diglycerin, and polyglycerin. Among these, polyhydric alcohols are preferred, more preferably one or more selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butylene glycol, and glycerin, and even more preferably one or more selected from the group consisting of dipropylene glycol, 1,3-butylene glycol, and glycerin. These alcohols can be used individually or in combination of two or more.

[0055] The aqueous medium content in the emulsified cosmetic composition of the present invention may be any amount within the range that allows for an oil-in-water type cosmetic composition. From the viewpoint of improving emulsification stability, it is preferably 40% by mass or more, more preferably 45% by mass or more, even more preferably 47% by mass or more, and preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less. More specifically, it is preferably 40 to 90% by mass, more preferably 45 to 80% by mass, and even more preferably 47 to 75% by mass. When the emulsified cosmetic composition of the present invention contains a polyhydric alcohol, the content of the polyhydric alcohol in the emulsified cosmetic composition is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, and preferably 7% by mass or less, more preferably 5% by mass or less, and even more preferably 4% by mass or less, from the viewpoint of improving emulsification stability. More specifically, it is preferably 0.5 to 7% by mass, more preferably 1 to 5% by mass, and even more preferably 2 to 4% by mass.

[0056] The emulsified cosmetic composition of the present invention can be suitably used as hair cosmetics such as shampoos, rinses, and conditioners; and as skin cosmetics such as facial cleansers, makeup removers, sunscreens, masks, and massage cosmetics. Among these, the emulsified cosmetic composition of the present invention has excellent UV protection effects, and is therefore preferably used for sunscreen applications, such as sunscreen cosmetics (lotions, creams, emulsions, serums, etc.), suntans, makeup bases, and foundations. The emulsified cosmetic composition of the present invention can be applied in various forms, including liquid, emulsion, cream, paste, solid, and multilayer forms, and can also be applied as a sheet, spray, or mousse.

[0057] (Method for manufacturing oil-in-water emulsion cosmetics) The method for producing the oil-in-water emulsion cosmetic of the present invention is not particularly limited, and known methods can be used as appropriate depending on the dosage form of the oil-in-water emulsion cosmetic. For example, one method may include the step of blending component (A), component (B), component (C), and optionally the aforementioned optional components, and uniformly mixing them using a homomixer or the like.

[0058] As a method for producing the emulsified cosmetic of the present invention, a method is preferred that includes the step of mixing and emulsifying a dispersion in which component (A) is dispersed in an oil phase component containing component (C) and optionally the aforementioned oil-soluble optional component, and an aqueous phase component preparation containing component (B), an aqueous medium, and optionally the aforementioned water-soluble optional component, from the viewpoint of improving the dispersibility of component (A) in the emulsified cosmetic, improving the UV protection effect, emulsion stability, and ease of crumbling and breaking of the formulation during application, as well as suppressing the feeling of friction during application and the feeling of tightness after application. A method including the following steps I to III is more preferred. Step I: Add component (A) to component (C) and, if necessary, to the aforementioned oil-soluble oil phase component, mix uniformly, and obtain a dispersion (i) in which component (A) is dispersed. Step II: A step to obtain preparation (ii) by uniformly mixing component (B), an aqueous medium, and an aqueous phase component containing the aforementioned water-soluble optional component as needed. Step III: Add the dispersion (i) obtained in Step I to the preparation (ii) obtained in Step II, mix uniformly, and emulsify to obtain an oil-in-water emulsion cosmetic.

[0059] From the viewpoint of improving the dispersibility of component (A) in the emulsified cosmetic, step I preferably includes the following steps I-1 and I-2. Step I-1: A step to obtain a preparation (i') by uniformly mixing component (C) and, if necessary, an oil phase component containing the aforementioned oil-soluble optional component. Step I-2: Add component (A) to the preparation (i') obtained in Step I-1, mix uniformly, and obtain a dispersion (i) in which component (A) is dispersed.

[0060] The mixing of the oil phase components in step I-1 and the mixing of the aqueous phase components in step II are preferably carried out by stirring while heating in a temperature range of 40°C to 90°C. In step II, the resulting preparation (ii) is preferably cooled to a temperature range of 15°C to 35°C and then further mixed uniformly. Furthermore, in step III, while stirring the preparation (ii) obtained in step II, it is preferable to add the dispersion (i) obtained in step I while maintaining it at a temperature of preferably 40°C to 90°C, and then uniformly mix and emulsify it.

[0061] With regard to the embodiments described above, the present invention further discloses the following embodiments.

[0062] <1> An oil-in-water emulsion cosmetic containing the following ingredients (A), (B), and (C), Component (A): One or more selected from the group consisting of hydrophobized titanium dioxide and zinc oxide with an average primary particle size of 1 nm to 70 nm. Component (B): Copolymer containing structural units derived from 2-acrylamido-2-methylpropanesulfonic acid and structural units derived from acrylic monomers. Ingredients (C): Betaine-type surfactant An oil-in-water emulsion cosmetic having an ingredient (A) content of 9% by mass or more and 27% by mass or less. <2> An oil-in-water emulsion cosmetic containing the following ingredients (A), (B), and (C), Component (A): One or more selected from the group consisting of hydrophobized titanium dioxide and zinc oxide with an average primary particle size of 5 nm to 50 nm. Component (B): Copolymer containing structural units derived from 2-acrylamido-2-methylpropanesulfonic acid and structural units derived from acrylic monomers. Ingredients (C): Betaine-type surfactant An oil-in-water emulsion cosmetic having an ingredient (A) content of 13% by mass or more and 20% by mass or less.

[0063] <3> The acrylic monomer is one or more selected from the group consisting of acrylic acid, acrylamide, dimethylacrylamide, alkyl acrylate, alkyl methacrylate, hydroxyalkyl acrylate, and polyoxyethylene alkyl ester of methacrylic acid (average number of moles of ethylene oxide added: 10 to 30). <1> or <2> The oil-in-water emulsion cosmetic described above. <4> The component (B) is one or more selected from the group consisting of (sodium acryloyldimethyltaurate / sodium acrylate) copolymer, (ammonium acryloyldimethyltaurate / beheneth-25 methacrylate) crosspolymer, and (ammonium acryloyldimethyltaurate / dimethylacrylamide / lauryl methacrylate / laureth-4 methacrylate) crosspolymer, as described above. <1> ~ <3> An oil-in-water emulsion cosmetic as described in any of the following. <5> The above is a copolymer in which component (B) is (sodium acryloyldimethyl taurate / sodium acrylate). <1> ~ <4> An oil-in-water emulsion cosmetic as described in any of the following. <6> The above, where component (C) is hydrogenated lecithin. <1> ~ <5> Oil-in-water emulsion cosmetic as described in any of the following

[0064] <7> The UV absorber content is less than 3% by mass, <1> ~ <6> An oil-in-water emulsion cosmetic as described in any of the following. <8> The UV absorber content is less than 1% by mass, <1> ~ <6> An oil-in-water emulsion cosmetic as described in any of the following. <9> The above, wherein the content of component (B) is 0.1% by mass or more and 3% by mass or less. <1> ~ <8> An oil-in-water emulsion cosmetic as described in any of the following. <10> The content of component (B) is 0.25% by mass or more and 0.5% by mass or less, <1> ~ <8> An oil-in-water emulsion cosmetic as described in any of the following. <11> The above, wherein the content of component (C) is 0.1% by mass or more and 3% by mass or less. <1> ~ <10> An oil-in-water emulsion cosmetic as described in any of the following. <12> The above, wherein the content of component (C) is 0.3% by mass or more and 0.7% by mass or less. <1> ~ <10> An oil-in-water emulsion cosmetic as described in any of the following.

[0065] <13> The mass ratio of component (A) to component (C) [(A) / (C)] is 7.5 or more and 75 or less, <1> ~ <12> An oil-in-water emulsion cosmetic as described in any of the following. <14> The mass ratio of component (A) to component (C) [(A) / (C)] is 20 or more and 40 or less, <1> ~ <12> An oil-in-water emulsion cosmetic as described in any of the following. <15> The mass ratio of component (A) to component (B) [(A) / (B)] is 10 or more and 90 or less, <1> ~ <14> An oil-in-water emulsion cosmetic as described in any of the following. <16> The mass ratio of component (A) to component (B) [(A) / (B)] is 30 or more and 50 or less, <1> ~ <14> An oil-in-water emulsion cosmetic as described in any of the following. <17> The mass ratio of component (B) to component (C) [(B) / (C)] is 0.3 or more and 3 or less, <1> ~ <16> An oil-in-water emulsion cosmetic as described in any of the following. <18> The mass ratio of component (B) to component (C) [(B) / (C)] is 0.7 or more and 1 or less, <1> ~ <16> An oil-in-water emulsion cosmetic as described in any of the following.

[0066] <19> The component (A) contains hydrophobized fine-particle zinc oxide, and the content of hydrophobized fine-particle zinc oxide in component (A) is 60% by mass or more, <1> ~ <18> An oil-in-water emulsion cosmetic as described in any of the following. <20> The component (A) contains hydrophobized fine-particle titanium dioxide, and the content of hydrophobized fine-particle titanium dioxide in component (A) is 50% by mass or more, <1> ~ <18> An oil-in-water emulsion cosmetic as described in any of the following. <21> The hydrophobic treatment of component (A) is one or more selected from the group consisting of silicone treatment, alkylalkoxysilane treatment, and fatty acid treatment. <1> ~ <20> An oil-in-water emulsion cosmetic as described in any of the following. <22> The above-mentioned, used for sunscreen purposes. <1> ~ <21> An oil-in-water emulsion cosmetic as described in any of the following.

[0067] <23> An oil-in-water emulsion cosmetic containing the following ingredients (A), (B), and (C), Component (A): One or more selected from the group consisting of hydrophobized titanium dioxide and zinc oxide with an average primary particle size of 1 nm to 70 nm. Component (B): One or more selected from the group consisting of (sodium acryloyldimethyltaurate / sodium acrylate) copolymer, (ammonium acryloyldimethyltaurate / beheneth-25 methacrylate) crosspolymer, and (ammonium acryloyldimethyltaurate / dimethylacrylamide / lauryl methacrylate / laureth-4 methacrylate) crosspolymer. Ingredient (C): Hydrogenated lecithin The content of component (A) is 9% by mass or more and 27% by mass or less. The UV absorber content is less than 3% by mass. An oil-in-water emulsion cosmetic used for sunscreen purposes. <24> An oil-in-water emulsion cosmetic containing the following ingredients (A), (B), and (C), Component (A): One or more selected from the group consisting of hydrophobized titanium dioxide and zinc oxide with an average primary particle size of 5 nm to 50 nm. Component (B): One or more selected from the group consisting of (sodium acryloyldimethyltaurate / sodium acrylate) copolymer, (ammonium acryloyldimethyltaurate / beheneth-25 methacrylate) crosspolymer, and (ammonium acryloyldimethyltaurate / dimethylacrylamide / lauryl methacrylate / laureth-4 methacrylate) crosspolymer. Ingredient (C): Hydrogenated lecithin The content of component (A) is 13% by mass or more and 20% by mass or less. The UV absorber content is less than 1% by mass, An oil-in-water emulsion cosmetic used for sunscreen purposes.

[0068] <25> The mass ratio of component (A) to component (C) [(A) / (C)] is 7.5 or more and 75 or less, <23> or <24> The oil-in-water emulsion cosmetic described above. <26> The mass ratio of component (A) to component (C) [(A) / (C)] is 20 or more and 40 or less, <23> or <24> The oil-in-water emulsion cosmetic described above. <27> The mass ratio of component (A) to component (B) [(A) / (B)] is 10 or more and 90 or less, <23> ~ <26> An oil-in-water emulsion cosmetic as described in any of the following. <28> The mass ratio of component (A) to component (B) [(A) / (B)] is 30 or more and 50 or less, <23> ~ <26> An oil-in-water emulsion cosmetic as described in any of the following. <29> The mass ratio of component (B) to component (C) [(B) / (C)] is 0.3 or more and 3 or less, <23> ~ <28> An oil-in-water emulsion cosmetic as described in any of the following. <30> The mass ratio of component (B) to component (C) [(B) / (C)] is 0.7 or more and 1 or less, <23> ~ <28> An oil-in-water emulsion cosmetic as described in any of the following. [Examples]

[0069] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0070] (Average primary particle size of component (A)) The average primary particle size of component (A) was measured by the following method. If the sample to be measured had a shape other than a plate, the pre-prepared dispersion of the sample was placed on the sample stage of a transmission electron microscope (TEM) (product name "JEM1400Plus", manufactured by JEOL Ltd.), air-dried, and then the maximum minor axis of 300 primary particles in the image observed by TEM at a magnification of 50,000x was measured. The number average of these measurements was taken as the average primary particle diameter. Here, the maximum minor axis refers to the minor axis with the longest length among the minor axes perpendicular to the major axis. If the sample to be measured had a plate-like shape, the thickness of 300 primary particles in the image observed under the same method and observation magnification conditions as described above was measured, and the number average of these measurements was taken as the average primary particle diameter. The dispersion of the measurement sample was prepared by adding 95 g of ethanol as a solvent to 5 g of the measurement sample and ultrasonically dispersing it.

[0071] Examples 1-10, Comparative Examples 1-5 Each oil-in-water emulsion cosmetic was obtained by the following method according to the formulations shown in Table 1. Components 9-14 shown in Table 1 were uniformly mixed, heated to 80°C, and dissolved to obtain preparation (i') (Step I-1). Next, while maintaining the obtained preparation (i') at 80°C, components 1-4 shown in Table 1 were added, uniformly mixed, and dispersed to obtain dispersion (i) (Step I-2). Separately, components 5-8 and 15-18 shown in Table 1 were heated at 40°C to dissolve, then naturally cooled to 25°C, and uniformly mixed to obtain preparation (ii) (Step II). While stirring the obtained preparation (ii), the dispersion (i) held at 80°C was added and uniformly mixed with a homomixer to emulsify and obtain an oil-in-water emulsion cosmetic (Step III).

[0072] The obtained oil-in-water emulsion cosmetic was evaluated for the following: (1) UV protection ability, (2) emulsion stability, and (3) usability (ease of breakdown of the formulation during application, lack of friction during application, and lack of tightness after application). The results are shown in Table 1.

[0073] (1) UV protection ability The oil-in-water emulsion cosmetic compositions shown in Table 1 were measured at 1.3 mg / cm² on a square PMMA plate (HelioScreen "HD6"). 2 The sample was uniformly coated with the specified amount and dried for 15 minutes to prepare the measurement sample. Similarly, glycerin was coated onto a PMMA plate and dried for 15 minutes to prepare the control sample. Using the SPF analyzer "UV-2000S" (manufactured by Labsphere), the in vitro SPF value was calculated from the absorption spectrum (measurement wavelength 290-450 nm), and the average of the in vitro SPF values ​​at 9 locations for each sample was taken as the UV protection capacity (SPF value).

[0074] (2) Emulsion stability The oil-in-water emulsion cosmetic compositions shown in Table 1 were visually observed immediately after preparation and after being stored at 40°C for one month, and evaluated according to the following criteria. 〔Judgment criteria〕 A: No separation or gelation was observed immediately after the cosmetic preparation, and no separation or gelation was observed even after storage at 40°C for one month. B: No separation or gelation was observed immediately after the cosmetic preparation, but slight separation or gelation was observed after storage at 40°C for one month. C: No separation or gelation was observed immediately after the cosmetic preparation, but clear separation or gelation was observed after storage at 40°C for one month. D: Separation or gelation is observed immediately after the cosmetic preparation.

[0075] (3) User experience (ease of disintegration of the formulation during application, lack of friction during application, lack of tightness after application) Ten expert panelists used the oil-in-water emulsion cosmetics shown in Table 1. At 25°C and 57% RH, 0.02 mL of each oil-in-water emulsion cosmetic was applied to the inside of the forearm in a 3 cm diameter circle and spread over 1 minute. The user experience was evaluated based on the following criteria: "ease of breakdown of the formulation during application," "lack of friction during application," and "lack of tightness after application." The average values ​​of the 10 participants were then used to determine the final judgment based on the following criteria. Furthermore, when the transparency after spreading was visually inspected, Examples 1-3 showed higher transparency compared to Example 4. [Evaluation Criteria] 5 points: very good 4 points: Good 3 points: Average 2 points: Slightly poor 1 point: Defective 〔Judgment criteria〕 A: 4.0 points or more and 5.0 points or less B: 3.0 points or higher, less than 4.0 points C: 2.0 points or higher, less than 3.0 points D: 1.0 points or more, less than 2.0 points

[0076] [Table 1]

[0077] The details of the ingredients used in Table 1 are shown below. *1: "MZY-303M2O" manufactured by Teika Co., Ltd. (hydrophobically treated zinc oxide fine particles, average primary particle size 30 nm) *2: "STR-100W-OTS" manufactured by Sakai Chemical Industry Co., Ltd. (hydrophobically treated titanium dioxide fine particles, average primary particle size 10 nm) *3: "BCASI TIO2 MP-701" manufactured by Daito Chemical Industries, Ltd. (hydrophobically treated pigment-grade titanium dioxide, average primary particle size 270 nm) *4: "STR-100W(G)" manufactured by Sakai Chemical Industry Co., Ltd. (Hydrophilic treated titanium dioxide fine particles, average primary particle size 10 nm) *5: SEPPIC's "SIMULGEL EG" ((Sodium Acrylate / Sodium Acryloyldimethyl Taurate) Copolymer, 37.5% by mass of active ingredient) *6: Clariant's "Aristoflex HMB" ((Acryloyldimethyltaurate Ammonium / Beheneth-25 Methacrylate) Crosspolymer, 100% by mass of active ingredient) *7: SEPIMAX ZEN manufactured by SEPPIC ((Acryloyldimethyltaurate Ammonium / Dimethylacrylamide / Lauryl Methacrylate / Laureth-4 Methacrylate) Crosspolymer, 100% by mass of active ingredient) *8:3V SIGMA "Syntalen K" *9: "PhosphoLipid PCSH70" manufactured by Nippon Seika Co., Ltd. *10: "NIKKOL HCO-60" (nonionic surfactant) manufactured by Nikko Chemicals Co., Ltd. *11: "KF-96A-6CS" manufactured by Shin-Etsu Chemical Co., Ltd.

[0078] Table 1 shows that the oil-in-water emulsion cosmetic composition according to the embodiment of the present invention has superior UV protection, excellent emulsification stability, is easily broken down as a formulation during application, and suppresses friction during application and tightness after application, compared to the oil-in-water emulsion cosmetic composition of the comparative example. Comparative Example 1 has a low UV protection effect because the content of component (A) in the oil-in-water emulsion cosmetic is less than 7% by mass. Comparative Example 2 uses pigment-grade titanium dioxide that has been hydrophobized as a metal oxide powder, resulting in low UV protection and insufficient emulsification stability. Comparative Example 3 uses hydrophilically treated fine titanium dioxide particles as a metal oxide powder, resulting in low UV protection and inferior usability (ease of the formulation breaking down during application, lack of friction during application, and lack of tightness after application). Comparative Examples 4 and 5 lacked an aqueous phase thickener or amphoteric surfactant containing a structure derived from 2-acrylamido-2-methylpropanesulfonic acid in their oil-in-water emulsion cosmetics, resulting in low UV protection and insufficient emulsion stability.

Claims

1. An oil-in-water emulsion cosmetic containing the following ingredients (A), (B), and (C), The content of component (A) is 7% by mass or more and 23% by mass or less. The content of component (B) is 0.15% by mass or more and 2% by mass or less. Component (B) is one or more selected from the group consisting of (sodium acryloyldimethyltaurate / sodium acrylate) copolymer and (ammonium acryloyldimethyltaurate / beheneth-25 methacrylate) crosspolymer. The mass ratio of component (B) to component (C) [(B) / (C)] is 0.5 or more and 1 or less. Oil-in-water emulsion cosmetic. (A) Hydrophobized metal oxide fine particles with an average primary particle diameter of less than 100 nm (B) Aqueous phase thickener containing a structure derived from 2-acrylamido-2-methylpropanesulfonic acid (C) Amphoteric surfactant

2. The oil-in-water emulsion cosmetic composition according to claim 1, wherein the mass ratio of component (A) to component (B) [(A) / (B)] is 10 or more and 80 or less.

3. The oil-in-water emulsion cosmetic composition according to claim 1 or 2, wherein the mass ratio of component (A) to component (C) [(A) / (C)] is 5 or more and 80 or less.

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