Water-in-oil emulsion cosmetic

Abstract

The present invention aims to provide a water-in-oil emulsion cosmetic that allows for a high concentration of ultraviolet scattering agents and pigments in a cosmetic base with a reduced amount of silicone compounds. [Solution] The water-in-oil emulsion cosmetic of the present invention comprises (A) a pigment surface-treated with a surface treatment agent containing an amino acid or a salt thereof, (B) an oil component, (C) a hydrophobic ultraviolet scattering agent, and (D) an oil phase thickener, wherein the amount of ultraviolet absorber is less than 1% by mass of the total amount of the cosmetic, and the amount of silicone oil is 10% by mass or less of the total amount of the cosmetic.

Description

Technical Field

[0001] The present invention relates to an oil-in-water emulsified cosmetic in which an ultraviolet scattering agent and a pigment can be highly formulated in a cosmetic base suppressing the blending amount of a silicone compound.

Background Art

[0002] Silicone compounds such as silicone oil have characteristics of high water repellency, no stickiness and a light feel in use, and good spreadability on the skin, and have the effect of improving the water resistance, usability of cosmetics containing the same, and the dispersibility of other blending components. Further, silicone compounds are also widely used as surface treatment agents for powder components.

[0003] Although silicone compounds have the above advantages, they have the problem of being difficult to remove cosmetics with water due to their high water repellency and poor detergency. Further, since silicone compounds are not usually biodegradable, there is a concern that they may accumulate in the environment for a long time, pollute the environment and disrupt the ecosystem. Therefore, in recent years, cosmetics called "silicone-free" that do not contain silicone compounds have attracted attention.

[0004] However, when excluding silicone compounds that have contributed to improving the dispersibility of other blending components such as powders in conventional cosmetics, problems such as difficulty in maintaining the stability of cosmetics occur.

[0005] On the other hand, in cosmetics, in order to protect the skin from the harm of ultraviolet rays, it is generally common to blend an ultraviolet absorber and an ultraviolet scattering agent. Usually, as the ultraviolet absorber, organic compounds such as ethylhexyl methoxycinnamate and octocrylene are used, and as the ultraviolet scattering agent, inorganic powder components such as titanium dioxide and zinc oxide are used.

[0006] While UV absorbers offer advantages such as high transparency, good spreadability on the skin, and resistance to sweat, they can cause irritation for users with sensitive skin because they protect against UV rays by converting them into other forms of energy, such as heat. Therefore, there is a demand for UV absorber-free, or "non-chemical," cosmetics that achieve UV protection using UV scattering agents instead of UV absorbers.

[0007] For example, Patent Document 1 proposes a water-in-oil emulsion cosmetic that improves cleanability by using N-acyl amino acids instead of silicone compounds as a surface treatment agent for powders, and also describes a formulation example that does not contain UV absorbers.

[0008] However, the cosmetic composition described in Patent Document 1 uses a silicone compound as a dispersion medium for the powder and therefore does not qualify as a silicone-free cosmetic composition. Silicone-free cosmetic compositions obtained by removing the silicone compound from the cosmetic composition described in Patent Document 1 have the problem that the powder tends to re-aggregate during storage, making it difficult to obtain excellent powder dispersibility. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2018-177736 [Disclosure of the Invention] [Problems that the invention aims to solve]

[0010] The present invention aims to provide a water-in-oil emulsion base that exhibits excellent temporal stability and powder dispersibility even when high concentrations of ultraviolet scattering agents and pigments are included in a cosmetic base with a reduced amount of silicone compound. [Means for solving the problem]

[0011] The inventors, after diligently conducting research to solve the aforementioned problems, discovered that by surface-treating the pigment to be blended into the oil phase with a surface treatment agent containing an amino acid or a salt thereof, and by blending an oil phase thickener, it is possible to incorporate a high concentration of pigment and ultraviolet scattering agent into the oil phase without incorporating a silicone compound, thus completing the present invention.

[0012] In other words, the present invention is (A) Pigments surface-treated with a surface treatment agent containing an amino acid or a salt thereof, (B) Oil, (C) Hydrophobic ultraviolet scattering agent, (D) Oil phase thickener Includes, The amount of UV absorber included is less than 1% by mass of the total amount of cosmetic product. The present invention provides a water-in-oil emulsion cosmetic characterized by containing 10% by mass or less of silicone oil relative to the total amount of the cosmetic. [Effects of the Invention]

[0013] The cosmetic composition according to the present invention, by having the above-described structure, can improve the powder dispersibility of an emulsifying base containing a high concentration of pigments and UV scattering agents, even without incorporating silicone compounds. Therefore, a silicone-free makeup cosmetic can be realized. Furthermore, according to the present invention, sufficient UV protection can be obtained by the high concentration of UV scattering agents without incorporating UV absorbers, thus enabling the realization of a non-chemical cosmetic. [Modes for carrying out the invention]

[0014] The cosmetic composition according to the present invention is characterized by comprising (A) a pigment surface-treated with a surface treatment agent containing an amino acid or a salt thereof, (B) an oil, (C) a hydrophobic ultraviolet scattering agent, and (D) an oil phase thickener. The components constituting the cosmetic composition of the present invention will be described in detail below.

[0015] <(A) Pigment> The (A) pigment (hereinafter sometimes simply referred to as "component (A)") incorporated into the cosmetic composition according to the present invention refers to an inorganic pigment whose surface has been treated with a surface treatment agent containing an amino acid or a salt thereof. By using a specific compound as the surface treatment agent, a cosmetic composition with excellent powder dispersibility is obtained. Only the following amino acids or their salts may be used as the surface treatment agent for the pigment of the present invention, or in addition to the following amino acids or their salts, other compounds commonly used as surface treatment agents for powders may be further included.

[0016] Specific examples of pigments include red iron oxide (red iron oxide), iron titanate, γ-iron oxide, yellow iron oxide, yellow ochre, black iron oxide, carbon black, lower titanium oxide, mango violet, cobalt violet, chromium oxide, chromium hydroxide, cobalt titanate, ultramarine, and Prussian blue. Among these, it is preferable to use pigment-grade iron oxides such as yellow iron oxide, red iron oxide, and black iron oxide, and pigment-grade titanium oxide as the pigments of the present invention. Here, pigment-grade refers to particles with an average particle size of 100 nm to 1 μm.

[0017] (A) Examples of "amino acids" used as a surface treatment agent for component (A) include glutamic acid, aspartic acid, and lysine, with glutamic acid and aspartic acid being preferred. The "amino acid" may also be an "acylated amino acid" in which an acyl group, preferably a saturated fatty acid having 12 to 20 carbon atoms, is condensed onto the amino group of the amino acid. Examples of the "acyl group" include a stearoyl group and a lauroyl group. The "salt" can be selected from alkali metal salts such as sodium and potassium, or alkaline earth metal salts, but sodium salts are preferred. Specific examples of acylated amino acids include disodium stearoyl glutamate, sodium lauroyl glutamate, and sodium lauroyl aspartate.

[0018] As a surface treatment agent for the component (A) of the present invention, by further adding "ester" to the above-mentioned "amino acid or its salt", the stability over time can be improved. The "ester" is a compound in which a monovalent or divalent fatty acid having 8 to 12 carbon atoms and a saturated aliphatic alcohol having 12 to 20 carbon atoms are bonded via an ester bond, and the alkyl chains of the fatty acid and the aliphatic alcohol may be linear or branched. Particularly, isostearyl sebacate is preferably used.

[0019] The pigment (A) of the present invention can be prepared by adsorbing an amino acid or its salt on the pigment surface by a conventional method.

[0020] As the surface treatment agent for the pigment (A) used in the present invention, a surface treatment agent containing an amino acid selected from sodium stearoyl glutamate and sodium lauroyl glutamate is preferable, and a surface treatment agent (NHS treatment agent) containing sodium stearoyl glutamate and isostearyl sebacate is more preferable.

[0021] Commercially available products can also be used as the pigment (A) of the present invention. Preferred commercially available products include, for example, NHS-treated powders such as NHS-Titanium CR-50, NHS-Red R516PS, NHS-Yellow LL-100P, NHS-Black BL-100P, NHS-Mica M-102, NHS-Talc JA-46R (manufactured by Mihoshi Kasei Kogyo Co., Ltd.), and the like.

[0022] The cosmetic of the present invention may be formulated by combining one or more kinds of the pigments treated with the above-mentioned surface treatment agent. The total blending amount of the (A) pigment is not particularly limited as long as the desired color can be obtained, but it is usually 0.1% by mass or more, for example, 1 to 20% by mass, preferably 2 to 10% by mass, based on the total amount of the cosmetic. If the blending amount is less than 0.1% by mass, sufficient color cannot be obtained, and if it exceeds 20% by mass, the stability tends to deteriorate.

[0023] <(B) Oil component> The (B) oil component (hereinafter sometimes simply referred to as "component (B)") incorporated into the cosmetic composition according to the present invention is not particularly limited as long as it is an oil component that is normally incorporated into cosmetics. Examples include hydrocarbon oils, ester oils, higher alcohols having 12 to 22 carbon atoms, fatty acids having 12 to 22 carbon atoms, and oils and fats. The cosmetic composition of the present invention can stably incorporate even polar oils, which were conventionally thought to reduce emulsification stability.

[0024] However, in the cosmetic composition of the present invention, the amount of silicone oil is 10% by mass or less, preferably 5% by mass or less, and more preferably 1% by mass or less, relative to the total amount of the cosmetic composition. Furthermore, the cosmetic composition of the present invention also includes embodiments that substantially do not contain silicone oil.

[0025] Examples of hydrocarbon oils include liquid paraffin, squalane, squalene, pristane, paraffin, isoparaffin, hydrogenated polyisobutene, olefin oligomers, and volatile hydrocarbon oils (e.g., isododecane, isohexadecane, undecane, tridecane, etc.).

[0026] Examples of ester oils include isopropyl myristate, cetyl ethylhexanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, isocetyl stearate, isocetyl isostearate, cholesteryl 12-hydroxystearate, ethylene glycol di2-ethylhexanoate, dipentaerythritol fatty acid ester, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, glyceryl di2-heptylundecanoate, trimethylolpropane tri2-ethylhexanoate, trimethylolpropane triisostearate, glyceryl triisostearate, pentaerythrityl tetraethylhexanoate, and Ethylhexanoin (glyceryl tri-2-ethylhexanoate), cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, glyceryl trimyristate, glyceride tri-2-heptylundecanoate, methyl castor oil fatty acid ester, oleyl oleate, cetostearyl alcohol, acetoglyceride, 2-heptylundecyl palmitate, diisobutyl adipate, N-lauroyl-L-glutamic acid Examples include -2-octyldodecyl, di2-heptylundecyl adipate, ethyl laurate, di2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, 2-ethylhexyl succinate, polypropylene glycol dipivalate, ethyl acetate, butyl acetate, amyl acetate, triethyl citrate, and other triester oils.

[0027] Examples of higher alcohols with 12 to 22 carbon atoms include oleyl alcohol, 2-decyltetradecinol, dodecanol, isostearyl alcohol, and octyldodecanol. Examples of fatty acids with 12 to 22 carbon atoms include oleic acid, isostearic acid, linoleic acid, and linolenic acid.

[0028] Examples of oils and fats include cocoa butter, avocado oil, camellia oil, macadamia nut oil, corn oil, olive oil, rapeseed oil, sesame oil, peach kernel oil, wheat germ oil, sasanqua oil, castor oil, linseed oil, safflower oil, cottonseed oil, elm oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, cinnamon oil, Japanese tung oil, jojoba oil, wheat germ oil, triglycerin, glyceryl trioctanoate, and glyceryl triisopalmitate.

[0029] In the cosmetic composition of the present invention, the dispersion stability of the powder is improved when the proportion of polar oil to the total amount of oil is 40% or more by mass. Therefore, in the cosmetic composition of the present invention, it is preferable that the proportion of polar oil to the total amount of oil is 40% or more.

[0030] Polar oils include oils with an IOB value of 0.05 to 0.80, particularly ester oils. Specific examples of polar oils include isostearic acid, jojoba oil, isopropyl myristate, cetyl octanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, isononyl isononanoate, cetyl lactate, myristyl lactate, isocetyl stearate, isocetyl isostearate, cetyl ethylhexanoate, cholesteryl 12-hydroxystearate, and di-2-ethylhexanoate. Diylene glycol, dipentaerythritol fatty acid ester, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, glyceryl di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, pentaerythritol tetra-2-ethylhexanoate, glyceryl tri-2-ethylhexanoate (triethylhexanoin), cetyl isooctanoate, cetyl 2-ethylhexanoate, 2-Ethylhexyl Lumitate, C12-C15 Alkyl Benzoate, Cetearyl Isononanoate, Caprylic / Capric Triglyceride, Butylene Glycol Dicaprylic / Capric Triglyceride, Glycerin Trimyristate, Glyceride Tri-2-Heptyl Undecanoate, Methyl Castor Oil Fatty Acid, Oleyl Oleate, Cetostearyl Alcohol, Acetoglyceride, 2-Heptyl Undecyl Palmitate, Diisobutyl Adipate, N-Lauroyl-L-Glutamate-2-Octyl Examples include decyl esters, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, di-2-ethylhexyl succinate, ethyl acetate, butyl acetate, amyl acetate, triethyl citrate, 2-ethylhexyl paramethoxycinnamate, tripylene glycol dipivalate, and 2-ethylhexyl 2-cyano-3,3-diphenylacrylate.

[0031] (B) The amount of oil is not particularly limited as long as it is the amount normally used when blending pigments and powders such as ultraviolet scattering agents into the oil phase, but for example, it is preferably 5 to 50% by mass of the total amount of cosmetic. If the amount of oil is less than 5% by mass, the stability decreases, and if it exceeds 50% by mass, the stability and usability tend to decrease.

[0032] <(C) Hydrophobic UV scattering agent> The (C) hydrophobic ultraviolet scattering agent (hereinafter sometimes simply referred to as "(C) component") incorporated into the cosmetic composition according to the present invention can be appropriately selected from those commonly used in cosmetics and is not particularly limited, but refers to those whose particle surface is hydrophobic. Specific examples include metal oxides, such as titanium dioxide, zinc oxide, iron oxide, cerium oxide, and tungsten oxide. In the present invention, titanium dioxide and zinc oxide are preferred. Furthermore, it is preferable that the average particle diameter is 0.1 μm or less. The lower limit of the average particle diameter is not particularly limited, but is usually around 5 nm.

[0033] The ultraviolet scattering agent used in the present invention may be either untreated or hydrophobic, as long as the particle surface is hydrophobic. Examples of hydrophobic surface treatment agents are not particularly limited, but include silicone treatment agents, fluorine compound treatment agents, amino acid treatment agents, fatty acid treatment agents, fatty acid soap treatment agents, fatty acid ester treatment agents, and others such as lecithin treatment agents and alkyl phosphate ester treatment agents.

[0034] Examples of silicone treatment agents include silicone oils such as methylhydrogenpolysiloxane, dimethylpolysiloxane, and methylphenylpolysiloxane; alkylsilanes such as methyltrimethoxysilane, ethyltrimethoxysilane, hexyltrimethoxysilane, and octyltrimethoxysilane; and fluoroalkylsilanes such as trifluoromethylethyltrimethoxysilane and heptadecafluorodecyltrimethoxysilane. Examples of fluorine compound treatment agents include perfluoroalkyl phosphate esters and perfluoroalcohols. Examples of amino acid treatment agents include N-acylglutamic acid, N-acylaspartic acid, and N-acyllysine. Examples of fatty acid treatment agents include palmitic acid, isostearic acid, stearic acid, lauric acid, myristic acid, behenic acid, oleic acid, rosinic acid, and 12-hydroxystearic acid. Examples of fatty acid soap treatment agents include aluminum stearate, calcium stearate, and 12-hydroxystearate. Examples of fatty acid ester treatment agents include dextrin fatty acid esters, cholesterol fatty acid esters, sucrose fatty acid esters, and starch fatty acid esters. These hydrophobic treatments can be carried out according to conventional methods.

[0035] According to the cosmetic composition of the present invention, since a high concentration of ultraviolet scattering agents can be incorporated into the oil phase, sufficient ultraviolet protection can be achieved without the inclusion of ultraviolet absorbers. Therefore, in the cosmetic composition of the present invention, the amount of ultraviolet absorber is 3% by mass or less of the total amount of the cosmetic composition, preferably 1% by mass or less. Furthermore, the cosmetic composition of the present invention also includes embodiments that substantially omit ultraviolet absorbers. By substantially omitting ultraviolet absorbers, a "non-chemical" cosmetic composition can be created.

[0036] "Non-chemical" cosmetics refer to cosmetics that provide skin protection from ultraviolet rays by containing inorganic ultraviolet scattering agents instead of organic ultraviolet absorbers.

[0037] (C) The amount of hydrophobic ultraviolet scattering agent is the amount necessary to obtain the desired ultraviolet protection effect and is not particularly limited, but is usually 1% by mass or more of the total amount of cosmetic composition, for example 5 to 30% by mass, preferably 10 to 30% by mass. If the amount is less than 5% by mass, it is difficult to obtain a sufficient ultraviolet protection effect, and if it exceeds 30% by mass, stability tends to deteriorate. When preparing the cosmetic composition of the present invention as a non-chemical cosmetic composition, it is preferable that the total content of ultraviolet scattering agents be 10% by mass or more.

[0038] <(D) Oil phase thickener> The (D) oil phase thickener (hereinafter sometimes simply referred to as "(D) component") incorporated into the cosmetic composition according to the present invention can be appropriately selected from substances that are commonly used as components in emulsified cosmetic compositions, etc., that thicken the oil phase by dissolving in oil or swelling with oil. Examples include dextrin fatty acid esters, sucrose fatty acid esters, solid or semi-solid hydrocarbon oils, organically modified clay minerals, or fatty acids or their salts.

[0039] Dextrin fatty acid esters are esters of dextrin or reduced dextrin with higher fatty acids, and are not particularly limited as long as they are commonly used in cosmetics. It is preferable to use dextrin or reduced dextrin with an average degree of polymerization of 3 to 100. Furthermore, it is preferable to use saturated fatty acids with 8 to 22 carbon atoms as the constituent fatty acids of the dextrin fatty acid ester. Specifically, examples include dextrin palmitate, dextrin oleate, dextrin stearate, dextrin myristate, and (palmitic acid / 2-ethylhexanoic acid) dextrin.

[0040] Sucrose fatty acid esters can preferably be those in which the fatty acid is linear or branched, saturated or unsaturated, and has 12 to 22 carbon atoms. Specifically, examples include sucrose caprylic acid ester, sucrose capric acid ester, sucrose lauric acid ester, sucrose myristic acid ester, sucrose palmitic acid ester, sucrose stearate ester, sucrose oleic acid ester, sucrose erucic acid ester, and the like.

[0041] Solid or semi-solid hydrocarbon oils are hydrocarbons that are solid or semi-solid at room temperature (25°C). Specific examples include ozokerite, ceresin, petrolatum, microcrystalline wax, hydrogenated palm oil, hydrogenated palm kernel oil, hydrogenated castor oil, hydrogenated peanut oil, hydrogenated rapeseed oil, hydrogenated camellia oil, hydrogenated soybean oil, hydrogenated olive oil, hydrogenated macadamia nut oil, hydrogenated sunflower oil, hydrogenated wheat germ oil, hydrogenated rice germ oil, hydrogenated rice bran oil, hydrogenated cottonseed oil, hydrogenated avocado oil, and waxes (carnauba wax, beeswax, candelilla wax, jojoba wax, Japanese wax, etc.).

[0042] Organically modified clay minerals are a type of colloidal hydrated aluminum silicate with a three-layer structure, and are typically those obtained by modifying clay minerals represented by the following general formula (I) with quaternary ammonium salt type cationic surfactants. (X,Y) 2―3 (Si,Al)4O 10 (OH)2Z 1 / 3 ·nH2O (I) (However, X=Al, Fe(III), Mn(III), Cr(III), Y=Mg, Fe(II), Ni, Zn, Li, Z=K, Na, Ca)

[0043] Specific examples include dimethyldistearylammonium hectorite (disteardimonium hectorite), dimethylalkylammonium hectorite, benzyldimethylstearylammonium hectorite, and magnesium aluminum silicate treated with distearyldimethylammonium chloride. Preferred commercially available products include Benton 27 (benzyldimethylstearylammonium chloride-treated hectorite: manufactured by Elementis Japan Co., Ltd.) and Benton 38 (distearyldimethylammonium chloride-treated hectorite: manufactured by Elementis Japan Co., Ltd.).

[0044] The fatty acid is not particularly limited as long as it can be used in cosmetics, etc., and can be selected from fatty acids having linear or branched saturated or unsaturated hydrocarbon groups. In particular, higher fatty acids that are solid at room temperature and have 8 to 22 carbon atoms, such as lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, isomyristic acid, and isopalmitic acid, are examples. Among these, it is especially preferable to use one or more selected from stearic acid, palmitic acid, and behenic acid. Examples of fatty acid salts include metal salts such as sodium salts, calcium salts, magnesium salts, and aluminum salts. In addition, amide derivatives and ester derivatives of fatty acids can also be used.

[0045] The (D) oil phase thickener of the present invention is preferably selected from dextrin fatty acid esters and organically modified clay minerals, and more preferably from organically modified clay minerals. As the oil phase thickener of the present invention, one or more substances selected from the above substances may be used in combination. (D) The amount of oil-phase thickener can be 0.01 to 10% by mass, preferably 0.1 to 5% by mass, and more preferably 0.1 to 2% by mass, relative to the total amount of cosmetic composition. If the amount is less than 0.01% by mass, sufficient emulsification stability cannot be obtained, and even if the amount exceeds 10% by mass, it tends not to be possible to obtain a further increase in effect.

[0046] According to the present invention, it is possible to realize a "silicone-free" cosmetic composition that does not contain silicone compounds. In this specification, "silicone compound" means a compound having a siloxane (-Si-O-Si-) structure in its molecule (e.g., silicones and siloxanes) and silanes (monosilanes, oligosilanes, polysilanes, and silane derivatives, e.g., alkylsilanes, alkoxysilanes, etc.), and includes silicone oils, silicone elastomers, silicone-based surfactants, and powders surface-treated with silicone compounds. Silicon dioxide (silica) is not included in the definition of "silicone compound" in this invention.

[0047] The cosmetic composition of the present invention, by combining a pigment treated with the above-mentioned specific surface treatment agent and the above-mentioned specific oil-phase thickener, exhibits excellent powder dispersibility and stability even as a silicone-free cosmetic composition.

[0048] In addition to the above-mentioned components, the cosmetic composition according to the present invention may also contain other optional components commonly used in topical skin preparations such as cosmetics and pharmaceuticals, as long as they do not impair the purpose and effects of the present invention. Examples of other optional components include powders other than components (A) and (C) above, surfactants, polymer compounds, chelating agents, lower alcohols, polyhydric alcohols, pH adjusters, antioxidants, fragrances, preservatives, disinfectants, and various other drugs. However, the present invention is not limited to these examples.

[0049] The cosmetic composition of the present invention can be manufactured according to conventional methods and can be in the form of liquid, emulsion, paste, cream, gel, solid, or other dosage forms. The cosmetic composition of the present invention can be provided as a makeup cosmetic such as a makeup base, foundation, concealer, blush, eyeshadow, mascara, eyeliner, eyebrow product, overcoat, or lipstick; or as a skincare cosmetic such as sunscreen. However, it is particularly suitable for use as a makeup cosmetic, especially as a makeup base or liquid foundation. [Examples]

[0050] The present invention will be further described below with reference to examples, but the present invention is not limited thereto. Unless otherwise specified, the amount of each component is expressed as a mass % of the system in which it is incorporated. Before describing each example in detail, the evaluation method used will be explained.

[0051] 1. Evaluation of powder dispersibility immediately after preparation. Immediately after preparation, the appearance of the sample was visually observed, and the dispersibility of the powder was evaluated based on the following criteria. Fewer colored stripes indicate more uniform dispersion of the powder. A: No color stripes are visible at all. B: Slight color stripes were present, but not to the extent that it would not affect its use. C: Color stripes are clearly visible. D: Color stripes are visible, making it unsuitable for use as a cosmetic product.

[0052] 2. Evaluation of powder dispersibility over time (rolling test) A rolling test was conducted to evaluate the powder's dispersibility over time. Specifically, half of the sample was filled into a cylindrical container, and the sample was rotated at 45 rpm for 4 hours at room temperature using a rolling tester (manufactured by Nigorikawa Rika Kogyo Co., Ltd.). After rotational motion, the sample filled into the container was visually observed to see if colored stripes appeared on the container wall, and the dispersibility of the powder was evaluated based on the following criteria. Fewer colored stripes indicate more uniform dispersion of the powder. A: No color stripes are visible at all. B: Slight color stripes were present, but not to the extent that it would not affect its use. C: Color stripes are clearly visible. D: Color stripes are visible, making it unsuitable for use as a cosmetic product.

[0053] 3. Evaluation of stability over time The sample was filled into a screw-cap tube (50 ml) and left to stand in a 50°C constant temperature bath for two weeks. Viscosity changes were measured using a rotational viscometer (bismetron rotational viscometer) before and after standing, and the emulsion particles and appearance were observed and evaluated based on the following criteria. A: There is no change in viscosity, and there are no problems with the emulsion particles or appearance. B: Slight changes in viscosity, emulsion particles, and appearance were observed, but these did not pose any problems for use. C: Changes in viscosity, emulsion particles, and appearance can be observed. D: Changes in viscosity, emulsion particles, and appearance were observed, making it unsuitable for use as a cosmetic product.

[0054] Water-in-oil emulsion cosmetics having the compositions listed in the table on the next page were prepared by conventional methods. The stability and powder dispersibility of the prepared samples were evaluated according to the evaluation method described above. The results are shown in the table.

[0055] [Table 1]

[0056] *1: NHS-Titanium CR-50 (manufactured by Miyoshi Chemical Industries Co., Ltd.) *2: NHS-Yellow LL-100P (manufactured by Miyoshi Chemical Industry Co., Ltd.) *3: NHS-Red R516PS (manufactured by Miyoshi Chemical Industry Co., Ltd.) *4: ASL-1 TiO2 CR-50 (manufactured by Daito Chemical Industries Co., Ltd.) *5: ASL-Yellow LL-100P (manufactured by Daito Kasei Kogyo Co., Ltd.) *6: ASL-Red R516P (manufactured by Daito Chemical Industries Co., Ltd.) *7: ASI TiO2 CR-50 (manufactured by Daito Chemical Industries Co., Ltd.) *8: ASI-Yellow LL-100P (manufactured by Daito Kasei Kogyo Co., Ltd.) *9: ASI-RED R516P (manufactured by Daito Kasei Kogyo Co., Ltd.) *10: NAI-Titanium CR-50 (manufactured by Miyoshi Chemical Industries Co., Ltd.) *11: NAI-Yellow LL-100P (manufactured by Miyoshi Chemical Industry Co., Ltd.) *12: NAI-Red R516PS (manufactured by Miyoshi Chemical Industry Co., Ltd.) *13: LL TiO2 CR-50 (manufactured by Daito Chemical Industries Co., Ltd.) *14: LL-Yellow LL-100P (manufactured by Daito Kasei Kogyo Co., Ltd.) *15: LL-Red R516P (manufactured by Daito Kasei Kogyo Co., Ltd.) *16: MI-Titanium CR-50 (manufactured by Miyoshi Chemical Industries Co., Ltd.) *17: MI-Yellow LL-100P (manufactured by Miyoshi Chemical Industry Co., Ltd.) *18: MI-Red R516PS (manufactured by Miyoshi Chemical Industry Co., Ltd.) *19: ST-485SA (manufactured by Titanium Industry Co., Ltd.) *20: WSX-MZ-500 (manufactured by Teika Co., Ltd.)

[0057] As shown in the table, the cosmetic composition of Comparative Example 1, which did not contain the oil phase thickener (D) of the present invention, exhibited poor powder dispersibility over time. Furthermore, the cosmetic compositions of Comparative Examples 2 and 3, which contained pigments treated with a fatty acid soap treatment agent (MI treatment) and a silicone treatment agent (EP1 treatment) for hydrophobicity, showed significant color stripes immediately after preparation, and also exhibited poor powder dispersibility and stability over time. On the other hand, the cosmetics of Examples 5 to 8, which incorporated pigments hydrophobized using a surface treatment agent containing an acylated amino acid metal salt and an amino acid (ASL treatment), a surface treatment agent containing an acylated amino acid metal salt and an ester metal complex (ASI treatment), and an acylated amino acid treatment agent (NAI treatment, LL treatment), were able to prepare cosmetics in which the powder was sufficiently dispersed, although they exhibited inferior powder dispersibility and stability over time. The cosmetic compositions of Examples 1 to 4, which contain a pigment hydrophobized using a surface treatment agent (NHS treatment) containing an amino acid salt and ester acylated with a saturated fatty acid as component (A) of the present invention, showed little to no color fringing immediately after preparation and after rolling tests, and also exhibited excellent stability over time.

[0058] [Section 1] (A) Pigments surface-treated with a surface treatment agent containing an amino acid or a salt thereof, (B) Oil, (C) Hydrophobic ultraviolet scattering agent, (D) Oil phase thickener Includes, The amount of UV absorber included is less than 1% by mass of the total amount of cosmetic product. An oil-in-water emulsion cosmetic in which silicone oil is present in an amount of 10% by mass or less relative to the total amount of the cosmetic. [Section 2] The water-in-oil emulsion cosmetic according to item 1, wherein the amino acid of component (A) is glutamic acid or aspartic acid. [Section 3] The water-in-oil emulsion cosmetic composition according to claim 1 or 2, wherein the component (A) is a pigment surface-treated with a surface treatment agent comprising an amino acid acylated with a saturated fatty acid or its salts and esters thereof. [Section 4] The water-in-oil emulsion cosmetic according to any one of items 1 to 3, wherein the amount of the hydrophobic ultraviolet scattering agent (C) is 10% by mass or more of the total amount of the cosmetic. [Section 5] The water-in-oil emulsion cosmetic composition according to any one of items 1 to 4, wherein the proportion of polar oil in the oil content (B) is 40% or more by mass. [Section 6] The water-in-oil emulsion cosmetic according to any one of claims 1 to 5, wherein the (D) oil phase thickener is an organically modified clay mineral. [Section 7] The water-in-oil emulsion cosmetic according to any one of claims 1 to 5, wherein the (D) oil phase thickener is dimethyldistearylammonium hectorite.

Claims

1. (A) A pigment surface-treated with a surface treatment agent containing an amino acid acylated with a saturated fatty acid or a salt thereof, in an amount of 0.1 to 20% by mass relative to the total amount of the cosmetic composition. (B) Oil, (C) 5 to 30% by mass of a hydrophobic ultraviolet scattering agent, based on the total amount of the cosmetic composition, (D) Oil phase thickener selected from organically modified clay minerals Includes, The amount of UV absorber included is less than 1% by mass of the total amount of cosmetic product. The amount of silicone oil is 10% by mass or less relative to the total amount of the cosmetic product. The proportion of polar oil to the total amount of oil in (B) above is 40% or more by mass, Volume median particle size d: 0.1–90 μm ５０ It does not contain surface-reacting calcium carbonate having, The surface-reacting calcium carbonate consists of natural pulverized calcium carbonate or precipitated calcium carbonate, carbon dioxide, and one or more H2O2. ３ O ＋ It is a reaction product with an ion donor, and carbon dioxide is H ３ O ＋ A water-in-oil emulsion cosmetic, formed in situ by ion donor treatment and / or supplied from an external source.

2. The water-in-oil emulsion cosmetic according to claim 1, wherein the acylated amino acid used as a surface treatment agent for the pigment (A) is glutamic acid or aspartic acid.

3. The pigment (A) is a pigment that has been surface-treated with a surface treatment agent containing an amino acid acylated with a saturated fatty acid or its salt and ester, The water-in-oil emulsion cosmetic composition according to claim 1 or 2, wherein the ester is a compound in which a monovalent or divalent fatty acid having 8 to 12 carbon atoms and a saturated aliphatic alcohol having 12 to 20 carbon atoms are linked via an ester bond.

4. The water-in-oil emulsion cosmetic according to any one of claims 1 to 3, wherein the amount of the hydrophobic ultraviolet scattering agent (C) is 10% by mass or more with respect to the total amount of the cosmetic.

5. The water-in-oil emulsion cosmetic composition according to any one of claims 1 to 4, wherein the (D) oil phase thickener is dimethyldistearylammonium hectorite.

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