JP7348767B2 - Oil-in-water emulsion cosmetic and method for producing the same - Google Patents

Description

The present invention relates to an oil-in-water emulsion cosmetic containing an ultraviolet scattering agent and a method for producing the same.

As the importance of sunscreen measures in daily life has been pointed out, cosmetics containing UV absorbers and UV scattering agents have been developed to effectively block UV irradiation to the skin.

As the ultraviolet scattering agent, powders of metal oxides (particulate metal oxides) such as zinc oxide and titanium oxide are generally used. When blending fine-particle metal oxides, water-in-oil emulsified cosmetics have been used to maintain good powder retention and dispersibility after application to the skin.

In recent years, there has been a demand for oil-in-water emulsion cosmetics that have a high level of ultraviolet protection but also have a feeling of use comparable to that of general skin care cosmetics. However, in the case of oil-in-water emulsion cosmetics, if a large amount of fine particle metal oxide is blended in an attempt to achieve a high SPF (Sun Protection Factor), the retention and dispersibility of the powder on the skin will deteriorate, resulting in a poor feeling of use. be damaged.

In order to incorporate a large amount of particulate metal oxide, it is conceivable to incorporate a large amount of an oily component. However, if a large amount of oily components are blended, it becomes difficult to maintain a uniform emulsified state, and a uniform emulsified state may not be obtained in the first place.

Polyhydroxystearic acid and partially crosslinked alkyl-modified or phenyl-modified organopolysiloxane polymers have improved stability and usability by improving the dispersibility of the fine-particle metal oxides while containing fine-particle metal oxides. Oil-in-water emulsion cosmetics containing p-menthane (see Patent Document 1) and sunscreen emulsions containing p-menthane-3,8-diol (see Patent Document 2) are known.

Unexamined Japanese Patent Publication No. 2017-137300 Japanese Patent Application Publication No. 2017-088599

However, the oil-in-water emulsion cosmetic described in Patent Document 1 has a problem in that the content of particulate metal oxides that can be blended is less than 10% by mass, and the desired UV protection effect cannot be obtained.

On the other hand, the sunscreen emulsion described in Patent Document 2 can have a content of particulate metal oxides of 10% by mass. However, when an emulsifier is used to blend the particulate metal oxide and oil component, its content is as high as 3.0% by mass or more. When the emulsifier content is high, the emulsion tends to become sticky, resulting in a poor feeling of use. Moreover, if an attempt is made to reduce the emulsifier content, the emulsified state tends to become unstable.

Furthermore, the sunscreen emulsion described in Patent Document 2 has a higher content of emulsifier than the content of oily components. Therefore, the sunscreen emulsion described in Patent Document 2 has a problem in that it feels sticky due to the emulsifier.

Therefore, in view of the problems of the prior art described above, the present invention contains fine particle metal oxides to the extent that UV protection effects can be obtained, and reduces the emulsifier content while containing a relatively large amount of oily components. The problem to be solved by the invention is to provide a method for producing an oil-in-water emulsified cosmetic and an oil-in-water emulsified cosmetic produced by the method.

In an attempt to solve the above-mentioned problems, the present inventors conducted trial and error regarding the types and blending order of each component contained in the oil phase and the aqueous phase, the mixing method of the oil phase and the aqueous phase, etc. in the process of manufacturing cosmetics. As a result of repeated steps, surprisingly, an oil phase containing a lipophilic emulsifier, sodium acrylate/sodium acryloyldimethyltaurate copolymer, and liquid oil was prepared, along with a fine particle metal oxide, and an aqueous phase containing a hydrophilic emulsifier. Instead of normal phase emulsification, in which the oil phase is gradually added to the water phase and emulsified, phase inversion emulsification, in which the water phase is gradually added to the oil phase and emulsified, is used to obtain UV protection. We succeeded in obtaining an oil-in-water emulsified cosmetic that has a uniform emulsified state.

Further surprisingly, the present inventors found that the thus obtained oil-in-water emulsified cosmetic can have a lower emulsifier content than the fine particle metal oxide and liquid oil contents. Furthermore, since the particle size of the emulsified particles is small, it has been found that while enhancing the ultraviolet protection effect, the product has a feeling of use comparable to that of ordinary skin care cosmetics that do not contain an ultraviolet scattering agent.

The present inventors have finally succeeded in creating a method for producing an oil-in-water emulsified cosmetic and an oil-in-water emulsified cosmetic produced by the method, in order to solve the problems of the present invention. . The present invention was completed based on these findings and successful examples.

Therefore, according to one aspect of the present invention, the following methods and cosmetics are provided.
[1] In an oil phase containing a hydrophobized surface-treated fine particle metal oxide, a lipophilic emulsifier, a sodium acrylate/sodium acryloyldimethyltaurate copolymer, and a liquid oil,
adding an aqueous phase containing a hydrophilic emulsifier;
By phase inversion emulsification,
A method for producing an oil-in-water emulsion cosmetic, including a step of obtaining an oil-in-water emulsion cosmetic.
[2] Particulate metal oxide subjected to hydrophobization surface treatment,
a lipophilic emulsifier;
Sodium acrylate/sodium acryloyldimethyltaurate copolymer,
liquid oil and
An oil-in-water emulsion cosmetic which is a phase inversion emulsion and contains a hydrophilic emulsifier.
[3] The method or cosmetic according to any one of [1] to [2], wherein the hydrophilic emulsifier has an HLB of 8 or more.
[4] The method or cosmetic according to any one of [1] to [3], wherein the content of the hydrophobized surface-treated particulate metal oxide is 5% by mass to 20% by mass.
[5] The method or cosmetic according to any one of [1] to [4], wherein the total content of the lipophilic emulsifier and the hydrophilic emulsifier is less than 2% by mass.
[6] The cosmetic according to any one of [2] to [5], wherein the oil-in-water emulsion cosmetic further contains an ultraviolet absorber.
[7] The cosmetic according to any one of [2] to [6], wherein the oil-in-water emulsion cosmetic has a total content of oily components of 15% by mass or more.
[8] The oil-in-water emulsified cosmetic has a viscosity of 10,000 mPa·s or less and/or a volume average particle diameter of 9.5 μm or less, any one of [2] to [7]. Cosmetics listed in.
[9] The cosmetic according to any one of [2] to [8], wherein the oil-in-water emulsion cosmetic is a sunscreen emulsion.

According to the method of one embodiment of the present invention, it is possible to produce an oil-in-water emulsified cosmetic that has a UV protection effect and has a reduced content of emulsifier relative to oily components.

Since the cosmetic according to one embodiment of the present invention can stably maintain a uniform emulsified state, it is expected to be used and stored for a relatively long period of time after production. In addition, since the cosmetic of one embodiment of the present invention can provide a good feeling of use, such as moisturizing and lightness, it can be used in skin care products in the form of emulsion, lotion, beauty serum, etc. It is expected to be used in place of or in combination with cosmetics.

FIG. 1 is a diagram showing the measurement results of the volume average particle diameter of cosmetics as described in Examples.

The details of the method and cosmetics that are one aspect of the present invention will be explained below, but the technical scope of the present invention is not limited only by the matters in this item, and the present invention will be limited as long as it achieves its purpose. Various aspects can be taken.

Unless otherwise specified, each term herein is used in the sense commonly used by those skilled in the art and should not be construed as having an unduly limiting meaning. Furthermore, since the theories and speculations made in this specification were made based on the knowledge and experience of the present inventors, the technical scope of the present invention is not limited solely to such theories and speculations. It is not something that will be done.

For example, the term "and/or" means any one of the listed related items, or any or all combinations of two or more.
"Content" has the same meaning as concentration, and means the ratio of the amount of the component to the total amount of the cosmetic. In this specification, unless otherwise specified, the unit of content means "mass% (wt%)".
In the present specification, "~" in the numerical range is a range that includes the numbers before and after that, for example, "0% by mass to 100% by mass" is 0% by mass or more and 100% by mass or less. means a certain range.
"Feeling on use" means at least one kind of feeling selected from the group consisting of moisturization and lightness of spread when applying a cosmetic to the skin. In addition, "moisturizing" refers to a feeling of freshness while being moisturized but without an oily feeling while being applied to the skin. "Lightness of application" refers to the feeling of light touch with little resistance when applied to the skin. "Moisture" and "lightness of spread" can be evaluated and confirmed by the usability evaluation described in the Examples below.
"(Meth)acrylic acid" is a general term that includes acrylic acid and methacrylic acid.

[Method of one embodiment of the present invention]
A method according to one embodiment of the present invention is a method for producing an oil-in-water emulsion cosmetic.
In the method of one embodiment of the present invention, a hydrophilic emulsifier and a base are added to an oil phase containing a hydrophobized surface-treated fine particle metal oxide, a lipophilic emulsifier, a sodium acrylate/sodium acryloyldimethyltaurate copolymer, and a liquid oil. The method includes at least a step of obtaining an oil-in-water emulsified cosmetic by adding an aqueous phase containing water and carrying out phase inversion emulsification.

The oil phase in the method of one embodiment of the present invention includes at least a hydrophobized surface-treated particulate metal oxide, a lipophilic emulsifier, a sodium acrylate/sodium acryloyldimethyltaurate copolymer, and a liquid oil.

The fine particle metal oxide that has been subjected to hydrophobization surface treatment is not particularly limited as long as it is normally used as an ultraviolet scattering agent in cosmetics, and the shape, hydrophobization surface treatment method, type of metal oxide, and fine particle The shape, particle size, etc. can be selected as appropriate. The hydrophobized surface-treated fine particle metal oxide is, for example, a hydrophobized surface-treated particle having a spherical, rod-like, needle-like, spindle-like, plate-like, or irregularly shaped volume average particle diameter of nano-order (for example, Examples include, but are not limited to, zinc oxide, titanium oxide, and cerium oxide with a particle diameter of about 10 to 100 nm). The fine particle metal oxides subjected to hydrophobization surface treatment may be used singly or in combination of two or more of the above-mentioned metal oxides.

The method of hydrophobizing surface treatment of particulate metal oxides is not particularly limited, and examples include silica treatment with hydrous silica, silica, etc.; methylhydrogenpolysiloxane, methylhydrogenpolysiloxane/dimethylpolysiloxane copolymer, dimethylpolysiloxane, methylpolysiloxane. silicone treatment with aluminum hydroxide, aluminum oxide, etc.; silane treatment with triethoxycaprylylsilane, octyltriethoxysilane, hexyltrimethoxysilane, etc.; fatty acid treatment with palmitic acid, stearic acid, isostearic acid, etc.; fatty acid treatment metal soap treatment with alkali metal salts or alkaline earth metal salts; fluorine treatment with perfluoroalkyl phosphates, perfluoroalkyl phosphate diethanolamine salts, perfluoroalkyltrimethoxysilanes, etc.; These methods may be used alone or in combination of two or more. Among the above surface treatments, hydrophobic surface treatment using fine particle metal oxides has a rich track record in the cosmetics field, and can reduce the photocatalytic effect of fine particle metal oxides and reduce the impact on the skin to which they are applied. From this viewpoint, silica treatment, silicone treatment, aluminum treatment, and silane treatment are preferred, and a combination of these treatments is more preferred.

The hydrophobized surface-treated fine particle metal oxide may be either a fine particle metal oxide that has been subjected to a hydrophobization surface treatment according to a conventional method or a commercially available fine particle metal oxide. Examples of commercially available particulate metal oxides with hydrophobized surface treatment include "ST-457SA" (manufactured by Titan Kogyo Co., Ltd.), "MT-100Z" (manufactured by Teika Corporation), and "MT-150EX" (manufactured by Teika Corporation). ), "LT-050" (manufactured by Teika), "LT-051" (manufactured by Teika), "FLT-01" (manufactured by Teika), "STR-40-LP" (manufactured by Sakai Chemical Industry Co., Ltd.) , "DIS-11A" (manufactured by Sakai Chemical Industry Co., Ltd.), "DIS-12C" (manufactured by Sakai Chemical Industry Co., Ltd.), "SPD-T6" (manufactured by Shin-Etsu Chemical Co., Ltd.), "IOPP50TIJ" (manufactured by KOBO Dispatec Co., Ltd.) , "MZY-303S" (manufactured by Teika), "LZ-014" (manufactured by Teika), "LZ-021" (manufactured by Teika), "FLZ-01" (manufactured by Teika), "FINEX-25-" LPT" (manufactured by Sakai Chemical Industries, Ltd.), "DIF-AW4" (manufactured by Sakai Chemical Industries, Ltd.), "DIF-3W4" (manufactured by Sakai Chemical Industries, Ltd.), "SPD-Z6" (manufactured by Shin-Etsu Chemical Industries, Ltd.), " IOPP60ZSJ" (manufactured by KOBO Dispatec), but is not limited to these. When using a commercially available fine particle metal oxide dispersion that has been surface-treated to be hydrophobic, it is preferable that the dispersion medium is a non-polar oil agent.

The content of the hydrophobized surface-treated particulate metal oxide (hereinafter sometimes simply referred to as particulate metal oxide) is not particularly limited as long as it has a light scattering or light reflecting effect, but for example, It is 1% by mass to 30% by mass, and preferably 1% to 20% by mass, and 5% to 20% by mass, considering the dispersibility of the particulate metal oxide and the emulsion stability of the oil-in-water emulsion cosmetic. is more preferable, and even more preferably 9% by mass to 17% by mass. However, the dispersibility of fine particle metal oxides and the emulsion stability of oil-in-water emulsion cosmetics depend on the content of hydrophilic emulsifier in the water phase, sodium acrylate/sodium acryloyldimethyltaurine copolymer, liquid oil, etc. in the oil phase. Therefore, it is not determined only by the content of the fine particle metal oxide subjected to the hydrophobization surface treatment.

Lipophilic emulsifiers are used as emulsifiers in the cosmetics field, and are not particularly limited as long as they are fat-soluble and hardly or partially dispersed in water, but for example, , an emulsifier with an HLB of 2 to 7, etc., and preferably an emulsifier with an HLB of 3 to 6, from the viewpoint of improving the dispersibility of fine metal oxide particles and increasing the stability of the resulting oil-in-water emulsion cosmetic. Anionic surfactants, cationic surfactants, amphoteric surfactants and nonionic surfactants having an HLB of 3 to 6 are more preferred.

Specific examples of lipophilic emulsifiers include sorbitan sesquiisostearate, sorbitan monooleate, sorbitan sesquioleate, glyceryl stearate, glyceryl stearate (SE), polyglyceryl-2 triisostearate, polyglyceryl-2 diisostearate, and distearic acid. Examples include, but are not limited to, polyglyceryl-2, polyglyceryl-2 oleate, polyethylene glycol monostearate, PEG-3 glyceryl isostearate, and polyoxyethylene cetyl ether. The lipophilic emulsifier may be one manufactured according to a conventional method or one that is commercially available. Additionally, the lipophilic emulsifier may be included in commercial products containing other ingredients. As the lipophilic emulsifier, one type of the above-mentioned ones may be used alone or two or more types may be used in combination.

The content of the lipophilic emulsifier is not particularly limited as long as it can promote the dispersibility of the particulate metal oxide in the oil phase, but is, for example, 0.05% to 5% by mass, If the purpose is to reduce the total amount of emulsifier in the material, the upper limit is preferably 2% by mass, more preferably 1% by mass, and even more preferably 0.5% by mass; Considering this, the lower limit is preferably 0.1% by mass, more preferably 0.2% by mass, and even more preferably 0.3% by mass.

The sodium acrylate/sodium acryloyl dimethyl taurate copolymer is not particularly limited as long as it is a copolymer containing sodium acrylate and sodium acryloyl dimethyl taurate as monomer components. In addition to copolymers, copolymers of substituted or unsubstituted sodium acrylate and substituted or unsubstituted sodium acryloyldimethyltaurate, and copolymers containing further monomer components in addition to sodium acrylate and sodium acryloyldimethyltaurate. Examples include. As the sodium acrylate/sodium acryloyldimethyltaurate copolymer, one of the above-mentioned copolymers may be used alone or two or more thereof may be used in combination.

The sodium acrylate/sodium acryloyldimethyltaurate copolymer may be produced by a conventional method or commercially available. Commercially available sodium acrylate/sodium acryloyldimethyltaurate copolymer includes, for example, "SIMULGEL EG" (contains 37.5% by mass of sodium acrylate/sodium acryloyldimethyltaurate copolymer; manufactured by SEPPIC). Examples include sodium acrylate/sodium acryloyldimethyltaurate copolymer sold as .

The content of the sodium acrylate/sodium acryloyldimethyltaurate copolymer may be an amount that can increase the compatibility of the fine particle metal oxide, lipophilic emulsifier, and liquid oil in the oil phase and/or an amount that can promote phase inversion emulsification. Although not particularly limited, it is, for example, 0.05% by mass to 5% by mass, and from the viewpoint of increasing the stability of the resulting oil-in-water emulsified cosmetic, 0.1% by mass to 3% by mass. Preferably, 0.3% by mass to 2% by mass is more preferred.

The liquid oil is not particularly limited as long as it is a liquid oily component used in the cosmetics field, and examples thereof include oily components that are liquid at 25°C and are commonly used in cosmetics. , neopentyl glycol diethylhexanoate, neopentyl glycol dicaprate, triethylhexanoin, ethylhexyl palmitate, isopropyl palmitate, pentaerythrityl tetraisostearate, cetyl 2-ethylhexanoate, isononyl isononanoate, isotridecyl isononanoate, sebacic acid Ester oils such as diisopropyl, pentaerythrityl tetra-2-ethylhexanoate, diethylhexyl succinate, alkyl benzoates having 12 to 15 carbon atoms; octyldodecanol, oleyl alcohol, isostearyl alcohol, hexyldecanol, 2-decyltetradecinol, Higher alcohols such as monooleyl glyceryl ether (serakyl alcohol); dimethicone, lauryl PEG-9 polydimethylsiloxyethyl dimethicone, dimethylpolysiloxane, dimethylcyclopolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, higher alcohol-modified silicone Silicone oils such as oil; linear and branched hydrocarbon oils such as hydrogenated polyisobutene, liquid paraffin, light isoparaffin, squalane, squalene; polyhydroxystearic acid, isohexadecane, undecylenic acid, oleic acid, linoleic acid, linolenic acid higher fatty acids such as , arachidonic acid, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and isostearic acid; animal oils such as liquid lanolin; fluorinated oils such as fluoropolyether and perfluoroalkyl ether silicone; olive oil, jojoba oil, lavender oil, evening primrose oil, avocado oil, camellia oil, macadamia nut oil, corn oil, rapeseed oil, egg yolk oil, sesame oil, persic oil, wheat germ oil, sasanquat oil, castor oil, linseed oil, safflower oil, cottonseed oil, perilla oil, Examples include natural oil-based ingredients such as soybean oil, peanut oil, tea seed oil, kaya seed oil, rice bran oil, and rice germ oil. The liquid oil may be used alone or in combination of two or more. As the liquid oil, ester oils, higher alcohols and silicone oils are preferable because they can improve the dispersibility of the ultraviolet scattering agent in cosmetics, and it is further preferable that at least one of the liquid oils is an ester oil. preferable.

The content of liquid oil is not particularly limited as long as it can promote the dispersibility of the particulate metal oxide in the oil-in-water emulsified cosmetic, but is, for example, 5% to 25% by mass, and is suitable for oil-in-water emulsified cosmetics. In order to provide a cosmetic with a good feel while containing a large amount of particulate metal oxide, the amount is preferably 8% by mass to 20% by mass, more preferably 10% by mass to 17% by mass.

The oil phase preferably contains an ultraviolet absorber in order to make the obtained oil-in-water emulsion cosmetic have a greater ultraviolet protection effect. Examples of the ultraviolet absorber include diethylaminohydroxybenzoylhexyl benzoate, 2-hydroxy-4-methoxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, dimethoxybenzylidene dioxoimidazolidine propionic acid 2 - UV-A absorbers such as ethylhexyl, bis(reslucinyl)triazine, methylenebisbenzotriazolyltetramethylbutylphenol, t-butylmethoxydibenzoylmethane; ethylhexyl methoxycinnamate (2-ethylhexyl paramethoxycinnamate), paradimethylamino 2-ethylhexyl benzoate, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, dimethicodiethylbenzalmalonate, 2,4,6-trianilino-p-(carbo-2'-ethylhexyl-1'-) UV-B absorbers such as oxy)-1,3,5-triazine, 2-hydroxy-4-methoxybenzophenone, homomenthyl salicylate, octyl salicylate, UV-A such as bisethylhexyloxyphenol methoxyphenyl triazine, trisbiphenyl triazine, etc. - Examples include B-wave absorbers. These ultraviolet absorbers can be used alone or in combination of two or more.

The content of the ultraviolet absorber is not particularly limited as long as the ultraviolet absorbing effect is recognized, but it is, for example, 0.1% to 20% by weight, and is a stable oil-in-water that exhibits a good ultraviolet absorbing effect. In order to obtain a type emulsified cosmetic, the amount is preferably 1% by mass to 15% by mass, more preferably 5% by mass to 12% by mass.

In the method of one embodiment of the present invention, the oil phase contains, in addition to a hydrophobized surface-treated particulate metal oxide, a lipophilic emulsifier, a sodium acrylate/sodium acryloyldimethyltaurine copolymer, a liquid oil, and a UV absorber. It may also contain other components.

Other components in the oil phase are not particularly limited, and include, for example, lipophilic components used in ordinary oil-in-water emulsion cosmetics, and more specifically, moisturizers, cooling agents, preservatives, and chelating agents. , pH adjusters, antioxidants, thickeners, whitening agents, vitamins, various other medicinal ingredients, and fragrances. The contents of other components can be appropriately set by those skilled in the art, as long as they do not interfere with solving the problems of the present invention.

Other components in the oil phase may include hydrophilic emulsifiers. The hydrophilic emulsifier may be the same as or different from the hydrophilic emulsifier contained in the aqueous phase described later. The content of the hydrophilic emulsifier in the oil phase is not particularly limited as long as it does not interfere with uniform mixing of the components in the oil phase, but it is preferably 0% by mass to 1% by mass. Further, the content of the hydrophilic emulsifier in the oil phase is preferably lower than the content of the hydrophilic emulsifier in the aqueous phase, and more preferably less than 40% of the content of the hydrophilic emulsifier in the aqueous phase. , more preferably less than 30%.

The oil phase containing the hydrophobized surface-treated particulate metal oxide, the lipophilic emulsifier, the sodium acrylate/sodium acryloyldimethyltaurine copolymer, and the liquid oil, as well as any other components, is prepared by heating each component or at room temperature. It can be obtained by sequentially adding and mixing by stirring or the like. For example, a sodium acrylate/sodium acryloyldimethyltaurine copolymer is added to a mixture obtained by uniformly mixing a hydrophobized surface-treated particulate metal oxide, a lipophilic emulsifier, and a liquid oil using a stirrer. An oil phase is obtained by uniformly mixing using a stirrer or the like.

For example, when using a solid component that is solid at room temperature, such as paraben, as another component, the container containing the solid component in the liquid component is heated to about 60°C to dissolve the solid component. The contents of the container are mixed uniformly using a stirrer, and then the hydrophobized surface-treated particulate metal oxide, lipophilic emulsifier, and liquid oil are mixed with or without heating the container. An oil phase may be obtained by adding a UV absorber and a sodium acrylate/sodium acryloyldimethyltaurate copolymer and uniformly mixing the mixture using a stirrer.

The aqueous phase in the method of one embodiment of the present invention contains water as a base and at least a hydrophilic emulsifier.

Hydrophilic emulsifiers are used as emulsifiers in the cosmetics field and are not particularly limited as long as they are water-soluble and can be dispersed or dissolved in water. Examples include emulsifiers with an HLB of 8 to 20. From the viewpoint that a stable oil-in-water emulsified cosmetic can be obtained by facilitating phase inversion emulsification, an emulsifier having an HLB of 10 to 18 is preferable, and an anionic surfactant having an HLB of 10 to 18 is more preferable. surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants, and more preferably nonionic surfactants with an HLB of 10 to 18.

Specific examples of hydrophilic emulsifiers include glycerin fatty acid esters such as self-emulsifying glyceryl monostearate; polyglycerin fatty acids such as polyglyceryl-6 laurate, polyglyceryl-10 myristate, polyglyceryl-10 stearate, and polyglyceryl-10 isostearate. Ester; polyoxyethylene glycerin such as PEG-5 glyceryl stearate, PEG-15 glyceryl stearate, PEG-15 glyceryl isostearate, PEG-20 glyceryl triisostearate, PEG-5 glyceryl oleate, PEG-15 glyceryl oleate, etc. Fatty acid ester; sorbitan fatty acid ester such as coconut fatty acid sorbitan, sorbitan palmitate; polyoxyethylene sorbitan fatty acid ester such as polysorbate 40, polysorbate 60, polysorbate 80, PEG-6 sorbitan stearate, PEG-20 sorbitan isostearate; sorbet laurate Polyoxyethylene sorbitol fatty acid esters such as -6, sorbeth tetraoleate-6, sorbet tetraoleate-30, and sorbet tetraoleate-60; Oxyethylene hydrogenated castor oil; polyoxyethylene alkyl ethers such as polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene behenyl ether; PEG-10 laurate, PEG-10 stearate, stearin Polyethylene glycol fatty acid esters such as acid PEG-25, stearate PEG-40, stearate PEG-45, stearate PEG-55, oleate PEG-10, distearate PEG-150, diisostearate PEG-8; hydrogenated lecithin , lecithin derivatives such as hydrogenated lysolecithin, etc., but are not limited to these.

The hydrophilic emulsifier may be one manufactured according to a conventional method or one that is commercially available. Moreover, the hydrophilic emulsifier may be included in a commercially available product containing other components. As the hydrophilic emulsifier, one type of the above-mentioned ones may be used alone, or two or more types may be used in combination.

The content of the hydrophilic emulsifier in the aqueous phase is not particularly limited as long as it can cause phase inversion emulsification and obtain an oil-in-water emulsion cosmetic as a phase inversion emulsion, but for example, from 0.05% by mass to 5% by mass, and if the purpose is to reduce the total amount of emulsifier in an oil-in-water emulsified cosmetic, the upper limit is preferably 2% by mass, more preferably 1% by mass, and 0.5% by mass. More preferably; in order to achieve good phase inversion emulsification and impart a good UV protection effect to the oil-in-water emulsion cosmetic, the lower limit is preferably 0.1% by mass, more preferably 0.2% by mass; More preferably, it is 0.3% by mass.

Water is used as the base for the aqueous phase. The water may be water that is normally used for producing cosmetics. The content of water is not particularly limited as long as it can constitute an oil-in-water emulsified cosmetic, but is, for example, 40% to 70% by weight, preferably 45% to 60% by weight.

In the method of one aspect of the invention, the aqueous phase may contain other ingredients in addition to water and a hydrophilic emulsifier.

Other components in the aqueous phase are not particularly limited, and include, for example, hydrophilic components used in ordinary oil-in-water emulsion cosmetics, and more specifically include humectants, cooling agents, preservatives, and chelating agents. , pH adjusters, antioxidants, thickeners, whitening agents, vitamins, various other medicinal ingredients, and fragrances. The contents of other components can be appropriately set by those skilled in the art, as long as they do not interfere with solving the problems of the present invention. Some of the other components that can be used in the oil phase and the aqueous phase are listed below, but these are illustrative only and are not limiting.

Examples of humectants include glycerin, diglycerin, trehalose, butylene glycol (BG), dipropylene glycol (DPG), xylitol, maltitol, maltose, sorbitol, glucose, fructose, hydrolyzed elastin, sodium lactate, cyclodextrin, Examples include pyrrolidone carboxylic acid, and one type thereof can be used alone or two or more types can be used in combination. The content of the humectant is preferably 0% to 15% by mass.

Examples of the chelating agent include alanine, disodium edetate, sodium polyphosphate, sodium metaphosphate, sodium phytate, trisodium phosphate, etc., and one of these may be used alone or in combination of two or more. Can be used. The content of the chelating agent is preferably 0% by mass to 0.5% by mass.

Examples of thickeners include water-soluble polymers, specifically hyaluronic acid, sodium hyaluronate, acetylated hyaluronic acid, acetylated sodium hyaluronate, chondroitin sulfate, sodium chondroitin sulfate, fucoidan, and tuberose polysaccharide. Water-soluble polysaccharides such as, Examples include synthetic polymers such as carbomer, polyacrylic acid, sodium polyacrylate, and acrylic acid polymers such as (meth)acrylic acid/alkyl (meth)acrylate copolymers. These thickeners can be used alone or in combination of two or more. The content of the thickener is preferably 0% by mass to 1% by mass. In order to improve the resulting oil-in-water emulsion cosmetic with respect to the squeaky feeling and finger-clamping feeling caused by the fine particle metal oxide, it is preferable to incorporate a water-soluble polymer.

Examples of preservatives include propylparaben, methylparaben, benzoic acid, salicylic acid, carbolic acid, sorbic acid, parachlorometacresol, hexachlorophene, benzalkonium chloride, chlorhexidine chloride, trichlorocarbanilide, photosensitizer, phenoxyethanol, ethylhexylglycerin. , alkanediols, etc., and one type of these can be used alone or two or more types can be used in combination. The content of the preservative is preferably 0% by mass to 1% by mass.

Examples of the pH adjuster include lactic acid, citric acid, glycolic acid, succinic acid, tartaric acid, malic acid, sodium malate, etidronic acid, potassium carbonate, sodium hydrogen carbonate, ammonium hydrogen carbonate, sodium hydroxide, potassium hydroxide, Examples include arginine, triethanolamine, monoethanolamine, etc., and one type of these can be used alone or two or more types can be used in combination. The content of the pH adjuster is preferably 0% by mass to 1% by mass.

Examples of antioxidants include vitamin E and its derivatives such as dibutylhydroxytoluene, butylhydroxyanisole, and d-δ-tocopherol; thiotaurine, evening primrose extract, β-carotene, catechin compounds, flavonoid compounds, and polyphenol compounds. , these can be used alone or in combination of two or more. The content of the antioxidant is preferably 0% by mass to 1% by mass.

The aqueous phase containing water, a hydrophilic emulsifier, and any other components can be obtained by sequentially adding each component with heating or at room temperature, and mixing by stirring or the like. For example, when using poorly water-soluble substances such as parabens and disodium edetate as other ingredients, heat a container containing water, a hydrophilic emulsifier, and other ingredients to about 60°C. The aqueous phase can be obtained by uniformly mixing the contents using a stirrer or the like.

In the method of one embodiment of the present invention, an oil-in-water emulsified cosmetic is obtained by adding an aqueous phase to the oil phase obtained as described above and performing phase inversion emulsification.

The operations and conditions for phase inversion emulsification can be appropriately set by those skilled in the cosmetics field. For example, as described in the examples below, the aqueous phase is gradually added to the oil phase at room temperature while stirring with a stirrer, and the emulsification state is visually checked while phase inversion emulsification is carried out. can be induced. At this time, it is preferable to gradually increase the stirring speed since the total amount of cosmetic increases and the viscosity increases due to emulsification. Further, after adding the entire amount of the aqueous phase to the oil phase, it is preferable to continue stirring for several minutes to obtain a stable oil-in-water emulsion cosmetic.

The contents of the oil phase and the aqueous phase are not particularly limited as long as the amount of the aqueous phase is large relative to the oil phase, but for example, the content of the oil phase is preferably 20% by mass to 49% by mass. is 30% to 45% by weight; the content of the aqueous phase is 51% to 80% by weight, preferably 55% to 70% by weight.

Specific examples of the method of one aspect of the present invention include, without stirring or using a stirrer with a stirring speed of 500 rpm to 1,000 rpm, at room temperature or heated to 50° C. to 70° C. Prepare an oil phase and an aqueous phase, then gradually add the aqueous phase to the oil phase at room temperature, and change the stirring speed from 3,000 rpm to 5,000 rpm depending on the increase in total volume and/or viscosity. to cause phase inversion emulsification, and then add the entire amount of the aqueous phase to the oil phase, and then continue stirring for several minutes, preferably about 3 to 10 minutes, to obtain an oil-in-water emulsified cosmetic. Examples include, but are not limited to, methods.

In the method of one aspect of the present invention, various steps and operations can be added before or after the above-described steps, or during the steps, as long as the problems of the present invention can be solved.

[Cosmetics according to one embodiment of the present invention]
A cosmetic according to one embodiment of the present invention is an oil-in-water emulsion cosmetic obtained by a method according to one embodiment of the present invention.

A cosmetic according to one embodiment of the present invention contains at least a fine particle metal oxide whose surface has been hydrophobized, a lipophilic emulsifier, a sodium acrylate/sodium acryloyldimethyltaurine copolymer, a liquid oil, and a hydrophilic emulsifier. and is a phase inversion emulsion. As long as the cosmetic according to one embodiment of the present invention has such a configuration, there are no particular limitations on properties such as physical properties, functions, and effects. However, the cosmetic according to one embodiment of the present invention preferably has at least one characteristic selected from the group consisting of volume average particle diameter, viscosity, pH, SPF, stability, and feeling on use as shown below.

In the cosmetic of one embodiment of the present invention, the volume average particle diameter of the emulsified particles is preferably smaller than the volume average particle diameter of the cosmetic of Comparative Example 5 described below, and more preferably 9.5 μm or less, It is more preferably 5.0 μm or less, and even more preferably 4.0 μm or less. Since the emulsified particles are fine emulsions, it is expected to maintain a more stable emulsified state, exhibit good SPF, and provide a good feeling of use to the skin. The volume average particle diameter of the emulsified particles can be measured using a laser diffraction particle size distribution meter as described in the Examples below.

When the cosmetic according to one embodiment of the present invention is in liquid form, the viscosity is preferably 10,000 mPa·s, more preferably 9,000 mPa·s or less. The lower limit of the viscosity is typically about 1,000 mPa·s. When the viscosity is much higher than 10,000 mPa·s, for example, 15,000 mPa·s or more, it approaches a cream-like form and may feel heavy on use. The viscosity can be measured using a BM type viscometer as described in the Examples below.

The pH of the cosmetic according to one embodiment of the present invention is preferably such that it does not destabilize the emulsified state and does not irritate the skin, more preferably from 6 to 9, and even more preferably from 7 to 8.5. The pH can be measured using a pH meter as described in the Examples below.

In order for the cosmetic of one aspect of the present invention to have an excellent UV protection effect, the SPF is preferably 20 or more, more preferably 22 or more, and even more preferably 25 or more. Even more preferably it is 27 or more. The upper limit of the SPF measurement value is typically about 100, and when displayed as a product, the upper limit is 50+, which indicates SPF 50 or higher. The SPF evaluation method can be measured using an SPF analyzer as described in the Examples below.

Regarding stability, the cosmetic composition of one embodiment of the present invention shows no phase separation or oil floating when stored at 40°C for one month according to the stability test described in the Examples below. Preferably, the level is not perceptible.

The cosmetic of one embodiment of the present invention has an average score among panelists based on control product 1 based on the feel of use regarding "moisture" and/or "lightness of spread" as described in the Examples below. is preferably larger than 1.0, more preferably 1.5 or more.

The cosmetic of one embodiment of the present invention has a volume average particle diameter, viscosity, pH, SPF, stability, and feeling of use within the above-mentioned preferred ranges, so that it has an ultraviolet protection effect, is stable, and can be used as a commercially available skin care product. It can be an oil-in-water emulsion cosmetic with a comparable feeling of use.

A more specific embodiment of the cosmetic according to one aspect of the present invention includes 5% to 17% by mass of a hydrophobically surface-treated fine particle metal oxide, 0.1% to 2% by mass of a lipophilic emulsifier, and acrylic. 0.1% to 2% by mass of sodium acid/sodium acryloyldimethyltaurine copolymer, 10% to 17% by mass of liquid oil, 0.2% to 1% by mass of hydrophilic emulsifier, and 40% by mass of water. % to 60% by mass (however, the total component content does not exceed 100% by mass), and is an oil-in-water emulsion cosmetic that is a phase inversion emulsion.

Another more specific embodiment of the cosmetic according to one embodiment of the present invention includes 5% to 15% by mass of an ultraviolet absorber, 5% to 17% by mass of a hydrophobized surface-treated particulate metal oxide, 0.1% to 2% by mass of an oil-based emulsifier, 0.1% to 2% by mass of sodium acrylate/sodium acryloyldimethyltaurate copolymer, 10% to 17% by mass of liquid oil, and a hydrophilic emulsifier. An in-water emulsion containing 0.2% by mass to 1% by mass, 40% to 60% by mass of water (however, the content of all components does not exceed 100% by mass), and is a phase inversion emulsion. It is an oil-based emulsified cosmetic.

Another more specific embodiment of the cosmetic according to one embodiment of the present invention includes 5% to 15% by mass of an ultraviolet absorber, 5% to 17% by mass of a hydrophobized surface-treated particulate metal oxide, 0.1% to 2% by mass of an oil-based emulsifier, 0.1% to 2% by mass of sodium acrylate/sodium acryloyldimethyltaurate copolymer, 10% to 17% by mass of liquid oil, and a hydrophilic emulsifier. It contains 0.2% by mass to 1% by mass and 40% to 60% by mass of water (however, the content of all components does not exceed 100% by mass), is a phase inversion emulsion, and is an emulsified emulsion. The volume average particle diameter of the particles is 9.5 μm or less, the viscosity is 4,000 mPa・s to 10,000 mPa・s, the pH is 6 to 9, the SPF is 20 to 50, and/or stable. It is an oil-in-water emulsion cosmetic with recognized properties.

The cosmetic according to one embodiment of the present invention can be designed to have a large total content of oily components such as liquid oil and ultraviolet absorbers, and a small total content of emulsifiers consisting of lipophilic emulsifiers and hydrophilic emulsifiers. . For example, in the cosmetic according to one embodiment of the present invention, the total content of oily components is preferably 15% by mass or more, more preferably 18% by mass to 30% by mass, and even more preferably 20% by mass to 28% by mass; The total content of emulsifiers is preferably less than 2% by weight, more preferably from 0.5% to 1.5% by weight, even more preferably from 0.7% to 1.2% by weight; The ratio of the total content of oily components to the total content of oily components (oily components/emulsifier) is preferably 15 or more, more preferably 20 to 50, and even more preferably 23 to 40.

The cosmetic of one embodiment of the present invention is not particularly limited in its usage mode or dosage form, and includes, for example, emulsion, lotion, serum, sunscreen gel, foundation, pack, hand cream, makeup base, concealer, and sunscreen. Examples include anti-emulsion. When the cosmetic according to one embodiment of the present invention is in a liquid dosage form such as an emulsion, a lotion, or a beauty serum, it can have a feel as good as that of a skin care cosmetic that does not contain an ultraviolet scattering agent. It is preferable because it can be used in place of skin care cosmetics. The cosmetics of one embodiment of the present invention are filled and sealed in containers made of materials such as glass, plastic, and metal such as aluminum, and are manufactured into products such as skin care cosmetics, makeup cosmetics, fragrance cosmetics, body care cosmetics, and all-in-one cosmetics. can be provided.

The cosmetic according to one embodiment of the present invention is expected to provide UV protection and a fresh feeling to the skin when applied to the skin, so it is preferable that the cosmetic be an oil-in-water emulsion cosmetic for the skin. preferable. Further, the cosmetic of one embodiment of the present invention can be used as an oil-in-water emulsion cosmetic for sunscreen or ultraviolet protection.

Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples, and the present invention can take various embodiments as long as the problems of the present invention can be solved. can.

[1. Preparation of cosmetics]
(1-1) Cosmetics of Examples 1 to 11 Cosmetics of Examples 1 to 11 were prepared according to the formulations shown in Table 1 and according to the following procedure. Note that the numerical values in the table represent mass % (wt%).

Phase A components were sequentially added to a 500 mL beaker, heated to about 60° C., stirred, and mixed uniformly to obtain Phase A.

The components of phase B were sequentially added to another 500 mL beaker and mixed uniformly by heating to about 60° C. and stirring to obtain phase B (aqueous phase).

At room temperature, each component of phase A' was added to phase A in sequence, and mixed uniformly by stirring at 500 rpm to 1,000 rpm using a homodisper ("Labolution"; manufactured by Primix). Then, while stirring, phase A'' was added and mixed uniformly to obtain an oil phase.

The aqueous phase was gradually added to the oil phase to induce phase inversion emulsification. At this time, since the total volume increases and the viscosity increases due to emulsification, the stirring speed is adjusted in the range of 3,000 rpm to 5,000 rpm, and after all the components of the aqueous phase are added, the mixture is stirred for 5 minutes. Cosmetics of Examples 1 to 11 were obtained.

(1-2) Cosmetics of Comparative Examples 1 to 4 Cosmetics of Comparative Examples 1 to 4 were obtained in the same manner as in (1-1) above according to the formulations shown in Table 1.

(1-3) Cosmetics of Comparative Example 5, Comparative Example 6, and Reference Example 4 (normal phase emulsification)
According to the formulation shown in Table 1, an oil phase and an aqueous phase were prepared in the same manner as in (1-1) above.

The oil phase was gradually added to the water phase to induce normal phase emulsification. At this time, the stirring speed was set to 3,000 rpm, and after all the components of the oil phase were added, the mixture was stirred for 5 minutes to obtain cosmetics of Comparative Example 5, Comparative Example 6, and Reference Example 4.

(1-4) Cosmetics of Reference Examples 1 to 3 Cosmetics of Reference Examples 1 to 3 were obtained in the same manner as in (1-1) above according to the formulations shown in Table 1.

[2. Evaluation method]

(2-1) Observation of emulsification state When observing the cosmetics visually and under a microscope, if a uniform emulsification state can be confirmed, rate it as “○”, and if a uniform emulsification state cannot be confirmed, rate it as “×” did.

(2-2) Particle size measurement The cosmetics were diluted with purified water and measured using a laser diffraction particle size distribution analyzer (SALD-2000J or SALD-2300; manufactured by Shimadzu Corporation) with a refractive index of 1.60. The volume average particle diameter (average value ± standard deviation) of the emulsified particles was measured at -0.10i.In addition, a microscope ("BX41"; manufactured by OLYMPUS) and a 5 million pixel high-definition microscope digital camera (" The state of emulsification was photographed using DP26 (manufactured by OLYMPUS).

(2-3) pH measurement The pH was measured using a pH meter (“pH METER F-22”; manufactured by Horiba, Ltd.) according to a conventional method.

(2-4) Viscosity measurement The viscosity was measured using a BM type viscometer (“VISCOMETER TVB-25L”; manufactured by Toki Sangyo Co., Ltd.). The measurement conditions were SPINDLE No. M3, 20 rpm. The viscosity value (mPa·s) of the cosmetics immediately after preparation was read 3 minutes after the start of measurement.

(2-5) SPF measurement SPF was measured using an SPF analyzer (“HM021224 UV-1000S”; manufactured by Labsphere) according to the following procedure.

A measurement plate was prepared by uniformly applying 33 mg (approximately 1.32 mg/cm ² ) of the cosmetic to a PMMA plate HD6 ("HelioScreen Labs HELIOPLATE HD6"; manufactured by Labsphere). Next, measurements were made at 10 points per plate using an SPF analyzer. The average of the obtained 10 measured values was taken as the SPF value of the cosmetic.

(2-6) Stability test After filling the cosmetic into a standard glass bottle and storing it at 40°C for one month, visually check for phase separation. If no phase separation has occurred, If phase separation occurred, it was evaluated as "x".

(2-7) Four panelists who had undergone usability evaluation training evaluated "moisturization" and "lightness of spread" using control product 1 by applying cosmetics directly to the skin. Scores were given according to the following criteria, and the average score and standard deviation among the panelists were determined.
"Comparative product 1":
Evaluation criteria for each item of the oil-in-water emulsified cosmetic, which had the same composition as Example 2 except that the oil agent triethylhexanoin was 10 wt%, and was obtained by normal phase emulsification:
2 points Superior to control product 1 1 point Same as control product 1 0 points Inferior to control product 1

[3. Evaluation results]
(3-1) Emulsified state The observation results of the emulsified state are shown in Table 1.

It was confirmed that the cosmetics of Examples 1 to 11 were uniformly emulsified by phase inversion emulsification. From this result, if the content of the hydrophilic emulsifier in the aqueous phase is 0.3 wt% to 0.5 wt%, even if the content of the ultraviolet scattering agent is changed to 9.0 wt% to 15.0 wt%, the phase inversion It was confirmed that emulsification resulted in uniform emulsification. Furthermore, it was found that the hydrophilic emulsifier used this time enables uniform emulsification by phase inversion emulsification.

The cosmetics of Comparative Examples 1 to 4 were not uniformly emulsified by phase inversion emulsification. From this result, it was found that even if the content of the hydrophilic emulsifier in the oil phase was increased, if the water phase did not contain the hydrophilic emulsifier, uniform emulsification would not occur due to phase inversion emulsification. However, even in this case, it was found from the cosmetics of Comparative Examples 5 and 6 that uniform emulsification was confirmed by normal phase emulsification.

(3-2) Particle size The measurement results of the particle size of the cosmetics of Example 2, Comparative Example 5, Comparative Example 6, and Reference Example 4 are shown in FIG. As shown in FIG. 1, it was found that the cosmetic of Example 2 produced by phase inversion emulsification had a smaller particle size than other cosmetics produced by normal phase emulsification.

(3-3) pH and viscosity Table 2 shows the results of measuring the pH and viscosity of the cosmetics of Examples 2, 4, and 8 to 11.

As shown in Table 2, the pH of the tested cosmetics was found to be within the range of 7.5 to 8.5, and the viscosity was found to be 10,000 mPa·s or less.

(3-4) SPF
Table 3 shows the measurement results of SPF of the cosmetics of Example 2, Example 4, Example 6, Comparative Example 5, Comparative Example 6, Reference Example 1, and Reference Example 4.

It was found that SPF increases when a hydrophilic emulsifier is contained in the aqueous phase and phase inversion emulsification is performed. The reason for this is that the fine metal oxide particles were well dispersed in the oil phase, and that good dispersibility was maintained even in phase inversion emulsification using an aqueous phase containing a hydrophilic emulsifier. It is presumed that the SPF of the final cosmetic was increased. It is a surprising finding that the SPF can be increased by the emulsifier-containing phase and the emulsification method, regardless of the emulsifier content.

(3-5) Stability When the stability of the cosmetics of Example 2, Example 4, Example 6, and Examples 8 to 11 was investigated, no phase separation was observed throughout the storage period, and all of them showed ” was evaluated.

(3-6) Feeling of use When we evaluated the feel of the cosmetics of Example 2, Comparative Example 5, and Reference Example 4, all of the panelists found that the cosmetics of Example 2 had a ``moisturizing'' and ``lightness of spread.'' ” was evaluated as superior to Control Product 1 (2 points). On the other hand, some panelists rated the cosmetic of Comparative Example 5 as having the same level (1 point) or inferior (0 points) to Control Product 1 in terms of "moisturization" or "lightness of spread." Therefore, it was found that the cosmetic of Example 2 was superior to the cosmetic of Comparative Example 5 in terms of the feeling of use regarding "moisture" and "lightness of spread." On the other hand, when comparing the cosmetics of Example 2 and Reference Example 4, there was almost no difference in "moisture" between the two, but the cosmetic of Example 2 was clearly superior in "lightness of spread". Ta.

In addition, when the cosmetic of Example 2 was compared with "HIKARIMIRAI Treatment Night Emulsion R" (seller: Hikari Mirai Co., Ltd.), which is a commercially available skin care cosmetic that does not contain UV scattering agents, it was found that "moisturizing" and " "Lightness of stretching" was about the same. On the other hand, when the cosmetic of Example 2 was evaluated for "smoothness", which means that it feels light and spreads thinly when applied to the skin, the cosmetic of Example 2 was superior to the above skin care cosmetic.

(3-7) Summary: An aqueous phase containing a hydrophilic emulsifier is added to an oil phase containing a hydrophobized surface-treated fine particle metal oxide, a lipophilic emulsifier, sodium acrylate/sodium acryloyldimethyltaurate copolymer, and liquid oil. The oil-in-water emulsion cosmetic obtained by phase inversion emulsification has a UV protection effect, contains a relatively large amount of oily components, and has a reduced emulsifier content. It was found that the particles had a finer particle size and had an excellent feel when used.

The method of one embodiment of the present invention can be used to produce on an industrial scale an oil-in-water emulsified cosmetic that has a UV protection effect and contains a relatively large amount of oily components but has a reduced content of emulsifier. can. By using the cosmetic of one embodiment of the present invention, a user can comfortably reduce or prevent the adverse effects of ultraviolet irradiation on the skin on a daily basis.

Claims (5)

In an oil phase containing 17% by mass or less of a hydrophobized surface-treated fine particle metal oxide, a lipophilic emulsifier , 0.56% by mass or more of a sodium acrylate/sodium acryloyldimethyltaurate copolymer, and a liquid oil,
adding an aqueous phase containing a hydrophilic emulsifier;
By phase inversion emulsification,
A method for producing an oil-in-water emulsion cosmetic, including a step of obtaining an oil-in-water emulsion cosmetic. The method according to claim 1, wherein the content of the sodium acrylate/sodium acryloyldimethyltaurate copolymer is 0.56% by weight to 2% by weight. The method according to any one of claims 1 to 2, wherein the hydrophilic emulsifier has an HLB of 8 or more. The method according to any one of claims 1 to 3, wherein the content of the hydrophobized surface-treated particulate metal oxide is 5% by mass to 17 % by mass . The method according to any one of claims 1 to 4, wherein the total content of the lipophilic emulsifier and the hydrophilic emulsifier is less than 2% by weight.