Oil-in-water sunscreen cosmetics

Abstract

To provide an oil-in-water type sunscreen cosmetic which is transparent when applied to the skin, has a fresh feeling of use and has a high ultraviolet protection effect.SOLUTION: There is provided an oil-in-water type sunscreen cosmetic which comprises (A) an aqueous component selected from a monovalent alcohol and a divalent alcohol, (B) a polyoxyalkylene-modified silicone, (C) an ultraviolet absorbing agent and (D) at least one ultraviolet protection power improver selected from the following: (D-1) a hydrophilic powder having a specific surface area of 190 m2 / g or more and (D-2) an oil phase thickener selected from a dextrin fatty acid ester, a sucrose fatty acid ester, a solid or semi-solid hydrocarbon oil, an organically modified clay mineral and a fatty acid or a salt thereof, wherein the amount of the aqueous component (A) is 1 to 15 mass% based on the total amount of the cosmetic in the case of a monovalent alcohol alone and is 1 to 20 mass% based on the total amount of the cosmetic in the case of a divalent alcohol alone and the total amount of a monovalent alcohol and a divalent alcohol is 1 to 45 mass% based on the total amount of the cosmetic in the case of a combination of a monovalent alcohol and a divalent alcohol.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to an oil-in-water type sunscreen cosmetic that is transparent when applied to the skin, has a refreshing feel, and provides high UV protection. [Background technology]

[0002] To protect the skin from the harmful effects of ultraviolet (UV) rays, cosmetics contain UV protection agents such as UV absorbers and UV scatterers. UV absorbers have advantages such as high transparency, good spreadability on the skin, and resistance to sweat, but because they are highly polar, incorporating them in large quantities into oil-in-water emulsion cosmetics can worsen emulsion stability. UV scatterers, which are inorganic powder components such as zinc oxide and titanium dioxide, reduce the harmful effects of UV rays on the skin by scattering and reflecting UV rays through a physical mechanism, and have the advantage of being less irritating compared to UV absorbers that generate thermal energy, but their inclusion can result in a loss of transparency when the cosmetic is applied to the skin, causing a white cast or a poor texture. Therefore, in order to achieve a high level of UV protection (high SPF) in sunscreen cosmetics, it is common practice to combine UV absorbers and UV scatterers in a balanced way, while utilizing the advantages of each.

[0003] In recent years, it has been known that by adsorbing flat, lamellar liquid crystal closures (silicone nanodiscs) formed by silicone-based surfactants onto the oil-water interface, an oil-in-water emulsion cosmetic with a refreshing feel and high emulsification stability can be obtained (Patent Document 1). Because this oil-in-water emulsion cosmetic has high emulsification stability, it has the advantage of being able to stably incorporate polar oils such as UV absorbers.

[0004] However, in the oil-in-water emulsion cosmetic using the above-mentioned silicone nanodiscs, even if a large amount of UV absorber is added instead of a UV scattering agent to obtain transparency of the coated film, it was difficult to obtain a high UV protection effect (high SPF) with only the addition of UV absorbers. Furthermore, when using highly polar UV absorbers, silicone oil is often incorporated to improve stability. However, in oil-in-water emulsion cosmetics using silicone nanodiscs, the inclusion of silicone-based raw materials tends to worsen the stability of the silicone nanodiscs, so it is necessary to avoid using silicone-based raw materials as much as possible.

[0005] Therefore, in oil-in-water emulsion cosmetics using silicone nanodiscs, it was difficult to obtain a cosmetic that is transparent when applied to the skin and has a high SPF while maintaining the stability and refreshing feel unique to silicone nanodiscs. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2021 / 177400 [Disclosure of the Invention] [Problems that the invention aims to solve]

[0007] The present invention aims to provide an oil-in-water emulsion cosmetic using silicone nanodiscs that can achieve a high UV protection effect (high SPF) without the use of UV scattering agents and has a refreshing feel. [Means for solving the problem]

[0008] As a result of diligent research to solve the aforementioned problems, the inventor discovered that by incorporating a specific compound into an oil-in-water emulsion cosmetic using silicone nanodiscs, the UV protection effect of the UV protection agent is improved, thus completing the present invention. In other words, this invention differs from the common method of combining UV absorbers and UV scatterers in sunscreen cosmetics to achieve a high SPF, and is based on the discovery that certain hydrophilic powders or certain oil-phase thickeners function as UV protection enhancers or amplifiers.

[0009] Thus, the present invention is (A) an aqueous component selected from monohydric alcohols and dihydric alcohols, (B) Polyoxyalkylene-modified silicone, (C) UV absorbers, and (D) At least one UV protection enhancer selected from the following: (D-1) Specific surface area is 190 m² 2 Hydrophilic powder of / g or more (D-2) Oil phase thickener selected from dextrin fatty acid esters, sucrose fatty acid esters, solid or semi-solid hydrocarbon oils, organically modified clay minerals, and fatty acids or their salts. Includes, The present invention provides an oil-in-water type sunscreen cosmetic in which the aqueous component (A) is present in an amount of 1 to 15% by mass of the total amount of the cosmetic when it is a monohydric alcohol alone, 1 to 20% by mass of the total amount of the cosmetic when it is a dihydric alcohol alone, and 1 to 45% by mass of the total amount of the cosmetic when it is a combination of a monohydric alcohol and a dihydric alcohol. [Effects of the Invention]

[0010] By adopting the above-described composition, the cosmetic composition according to the present invention can be made into an oil-in-water type sunscreen cosmetic that has a high UV protection effect simply by incorporating a UV absorber. In other words, the cosmetic composition of the present invention is transparent when applied to the skin and has a fresh feel like a skincare cosmetic, while achieving a high SPF. Furthermore, since the UV protection enhancement effects obtained by incorporating specific hydrophilic powders or specific oil-phase thickeners do not interfere with each other, there is an advantage to combining the hydrophilic powder and oil-phase thickener of the present invention in obtaining a high SPF.

Mode for Carrying Out the Invention

[0011] The oil-in-water type emulsified cosmetic according to the present invention is characterized by containing (A) an aqueous component selected from monohydric alcohols and dihydric alcohols, (B) a polyoxyalkylene-modified silicone, (C) an ultraviolet absorber, and (D) an ultraviolet protection power enhancer selected from specific compounds. Hereinafter, each component constituting the cosmetic of the present invention will be described in detail.

[0012] <(A) Aqueous Component> The (A) aqueous component (hereinafter sometimes simply referred to as the “(A) component”) blended in the cosmetic according to the present invention refers to one or more selected from monohydric alcohols and dihydric alcohols. The monohydric alcohol is not particularly limited as long as it is usually used in cosmetics, and examples thereof include ethyl alcohol (ethanol), normal propyl alcohol, isopropyl alcohol, etc. In the present invention, ethyl alcohol is preferred. The dihydric alcohol is not particularly limited as long as it is usually used in cosmetics, and examples thereof include 1,3-butylene glycol, dipropylene glycol, etc. In the present invention, 1,3-butylene glycol is preferred.

[0013] Although the spherical vesicles formed by the surfactant have surfaces entirely covered with hydrophilic groups, the nanodisks have lipophilic groups at the edge portions, so it is difficult to generate nanodisks in water. When (A) monohydric and dihydric alcohols are present in water, the surfactant (in the present invention, (B) polyoxyalkylene-modified silicone) is hydrophilized due to the solvent effect, and as a result, the transition from spherical vesicles to nanodisks is promoted.

[0014] On the one hand, when dissolving polyoxyalkylene-modified silicone such as PEG-12 dimethicone in alcohol, polyhydric alcohols such as trivalent alcohols like glycerin and polyhydric alcohols like sorbitol tend to lipophilize the surfactant and inhibit the transfer to nanodisks. Therefore, when formulating a trivalent or higher polyhydric alcohol, it is desirable to (A) make the total amount of monohydric and dihydric alcohols more than the total amount of polyhydric alcohols with a valence of 3 or higher.

[0015] When using a monohydric alcohol alone, its blending amount is 1 to 15% by mass based on the total amount of the cosmetic. When using a dihydric alcohol alone, its blending amount is 1 to 20% by mass based on the total amount of the cosmetic. Further, when using a combination of a monohydric alcohol and a dihydric alcohol, their total blending amount is 1 to 45% by mass based on the total amount of the cosmetic, preferably 1 to 35% by mass. More preferably, it is preferable to blend with the upper limit being the concentrations of the monohydric alcohol and the dihydric alcohol that satisfy the following formula (1). Concentration of monohydric alcohol in the aqueous phase (%) / 15 + Concentration of dihydric alcohol in the aqueous phase (mass%) / 20 ≤ 1 (1)

[0016] If the blending amount of the monohydric alcohol alone, the blending amount of the dihydric alcohol alone, or the total blending amount of the monohydric alcohol and the dihydric alcohol is less than 1% by mass, vesicles may not be formed or the structure may be disrupted and emulsification may not be possible. Further, if the blending amount of the monohydric alcohol alone exceeds 15% by mass, the blending amount of the dihydric alcohol alone exceeds 20% by mass, or the blending ratio of the monohydric alcohol and the dihydric alcohol is outside the range of the above formula (1), or even within the range of the above formula (1) but the total blending amount exceeds 45% by mass, the vesicle membrane may become too flexible or the vesicles may transfer to micelles and the stabilization effect may not be obtained.

[0017] <(B) Polyoxyalkylene-modified silicone> The (B) polyoxyalkylene-modified silicone (hereinafter sometimes simply referred to as "component (B)") incorporated into the cosmetic composition according to the present invention is a surfactant having a polysiloxane structure as a hydrophobic group and a polyoxyalkylene structure as a hydrophilic group, and is preferably a water-soluble silicone-based surfactant in which some of the methyl groups of dimethicone are replaced with polyethylene glycol. Specifically, it is represented by the following formula (2).

[0018] [ka]

[0019] In equation (2) above, R 1 A is either hydrogen or an alkyl group having 1 to 6 carbon atoms, and these may be the same or independently different. A is at least one of which is of formula (3): -(CH2) a -(C2H4O) b -(C3H6O) c -R 2 (3) The polyoxyalkylene group represented by is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and these may be the same or independently different. In formula (3), R 2 is hydrogen or an alkyl group having 1 to 6 carbon atoms, a is an integer from 1 to 6, b is an integer from 0 to 50, c is an integer from 0 to 50, and b+c is at least 5. In formula (2) above, m is an integer from 1 to 200, and n is an integer from 0 to 50. In the present invention, (B) polyoxyalkylene-modified silicone, it is preferable that the HLB is less than 10 in the HLB calculation using Griffin's formula.

[0020] In the cosmetic composition according to the present invention, (B) PEG-12 dimethicone, in particular, is preferred among polyoxyalkylene-modified silicones, where c is 0 and b is 12 in formula (3). Furthermore, it is even more preferable that the PEG-12 dimethicone has an HLB of less than 10.

[0021] DOWSIL is a commercially available product containing PEG-12 dimethicone. TMExamples include the ES-5373, SH3772M, SH3773M, SH3775M (all manufactured by Dow-Toray), and IM-22 (manufactured by Wacker Chemical).

[0022] The amount of component (B) is not particularly limited as long as it can form vesicles, which are precursors of nanodiscs, but for example, it is 0.1 to 5.0% by mass of the total amount of cosmetic composition, preferably 0.3 to 3.0% by mass, and more preferably 0.8 to 2.0% by mass. If the amount is less than 0.1% by mass, vesicles may not be formed sufficiently, and if it exceeds 5.0% by mass, the stability of the vesicles may be poor.

[0023] In this invention, vesicles refer to spherical closed bodies made of a bilayer film (lamellar liquid crystal). The cosmetic composition according to this invention contains nanodiscs made of the surfactant component (B). Vesicles, which are precursors of nanodiscs, can be formed by conventional methods. Specifically, vesicles made of component (B) are formed by mixing and stirring the aqueous component (A) and the polyoxyalkylene-modified silicone (B). When forming vesicles, in addition to the aqueous component (A), water or an aqueous component commonly used in cosmetics may be added in an amount that does not impair the stability of the vesicles. The average particle size of the vesicles is not particularly limited, but is usually around 30 nm to 150 nm.

[0024] Here, "nanodisc" refers to a flat lamellar liquid crystal closure body that uses vesicles (lamellar liquid crystal spherical closure bodies) formed by an amphiphilic substance as a precursor, and does not contain water-soluble components inside the closure body, and has lipophilic groups at its edges. In compositions without oil, nanodiscs exist as precursor vesicles, and by adding oil and performing emulsification, the vesicles undergo a structural change (hereinafter also referred to as "transformation") into nanodiscs. The nanodiscs of the present invention are obtained by mixing an aqueous component selected from monohydric alcohols and dihydric alcohols with a polyoxyalkylene-modified silicone to form vesicles, then adding an anionic surfactant and oil, and dispersing while applying strong stirring force. In the emulsified state, the nanodiscs exist adsorbed at the oil-water interface and contribute to emulsion stability. In this specification, since the amphiphilic substance that forms the vesicles is a silicone-based surfactant, the nanodiscs of the present invention are also referred to as "silicone nanodiscs."

[0025] <(C) UV absorber> The (C) UV absorber (hereinafter sometimes simply referred to as "(C) component") incorporated into the cosmetic composition according to the present invention may be one of those commonly incorporated into sunscreen cosmetics. Examples include benzoic acid derivatives, salicylic acid derivatives, cinnamic acid derivatives, dibenzoylmethane derivatives, β,β-diphenyl acrylate derivatives, benzophenone derivatives, benzylidene camphor derivatives, phenylbenzimidazole derivatives, triazine derivatives, phenylbenzotriazole derivatives, anthranyl derivatives, imidazoline derivatives, benzalmalonate derivatives, 4,4-diarylbutadiene derivatives, etc. Specific examples and trade names are listed below, but are not limited to these.

[0026] Examples of benzoic acid derivatives include ethyl para-aminobenzoate (PABA), ethyl-dihydroxypropyl PABA, ethylhexyl-dimethyl PABA (e.g., "Escalol 507"; ISP), glyceryl PABA, PEG-25-PABA (e.g., "Ubinal P25"; BASF), and diethylaminohydroxybenzoyl hexyl benzoate (e.g., "Ubinal A Plus").

[0027] Examples of salicylic acid derivatives include homosalate ("Eusolex HMS"; Rona / EM Industries), ethylhexyl salicylate or ethylhexyl salicylate (e.g., "NeoHeliopan OS"; Herman & Raymer), dipropylene glycol salicylate (e.g., "Dipsal"; Skell), and TEA salicylate (e.g., "NeoHeliopan TS"; Herman & Raymer).

[0028] Examples of cinnamic acid derivatives include octyl methoxycinnamate or ethylhexyl methoxycinnamate (e.g., "Parsol MCX"; Hoffmann-La Roche), isopropyl methoxycinnamate, isoamyl methoxycinnamate (e.g., "Neo-Heliopan E1000"; Herman & Raymer), cinnoxate, DEA methoxycinnamate, diisopropyl methylcinnamate, glyceryl-ethylhexanoate-dimethoxycinnamate, and di-(2-ethylhexyl)-4'-methoxybenzalmalonate.

[0029] Examples of dibenzoylmethane derivatives include 4-tert-butyl-4'-methoxydibenzoylmethane (e.g., "Parsol 1789").

[0030] Examples of β,β-diphenyl acrylate derivatives include octocrylene (e.g., "Ubinal N539T"; BASF).

[0031] Examples of benzophenone derivatives include benzophenone-1 (e.g., "Uvinal 400"; BASF), benzophenone-2 (e.g., "Uvinal D50"; BASF), benzophenone-3 or oxybenzone (e.g., "Uvinal M40"; BASF), benzophenone-4 (e.g., "Uvinal MS40"; BASF), benzophenone-5, benzophenone-6 (e.g., "Helisorb 11"; Norquay), benzophenone-8 (e.g., "Spectra-Sorb UV-24"; American Cyanamide), benzophenone-9 (e.g., "Uvinal DS-49"; BASF), and benzophenone-12.

[0032] Examples of benzylidene camphor derivatives include 3-benzylidene camphor (e.g., "Mexoryl SD"; CIMEX), 4-methylbenzylidene camphor, benzylidene camphor sulfonic acid (e.g., "Mexoryl SL"; CIMEX), benzalkonium camphor methosulfate (e.g., "Mexoryl SO"; CIMEX), terephthalylidene disodium camphor sulfonic acid (e.g., "Mexoryl SX"; CIMEX), and polyacrylamide methylbenzylidene camphor (e.g., "Mexoryl SW"; CIMEX).

[0033] Examples of phenylbenzimidazole derivatives include phenylbenzimidazole sulfonic acid (e.g., "Orthorex 232"; Merck) and phenyldibenzimimidazole tetrasulfonate disodium (e.g., "Neo-Heliopan AP"; Hermann & Raymer).

[0034] Examples of triazine derivatives include bis-ethylhexyloxyphenol methoxyphenyl triazine (e.g., "Tinosorb S"; Ciba Specialty Chemicals), ethylhexyl triazone (e.g., "Uvinal T150"; BASF), diethylhexyl butamide triazone (e.g., "Uvasorb HEB"; Sigma-3V), 2,4,6-tris(diisobutyl-4'-aminobenzalmalonate)-s-triazine, and 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine.

[0035] Examples of phenylbenzotriazole derivatives include drometrizole trisiloxane (e.g., "Silatrizole"; Rhodia Simiy Corporation) and methylenebis (benzotriazolyltetramethylbutylphenol) (e.g., "Tinosorb M" (Ciba Specialty Chemicals)).

[0036] Examples of anthranil derivatives include menthyl anthranilate (e.g., "Neo-Heliopan MA"; Herman & Raymer).

[0037] Examples of imidazoline derivatives include ethylhexyldimethoxybenzylidenedioxoimidazoline propionate.

[0038] Examples of benzalmalonate derivatives include polyorganosiloxanes having a benzalmalonate functional group (e.g., polysilicone-15; "Parsol SLX"; DSM Nutrition Japan).

[0039] Examples of 4,4-diarylbutadiene derivatives include 1,1-dicarboxy(2,2'-dimethylpropyl)-4,4-diphenylbutadiene.

[0040] The (C) ultraviolet absorber used in the present invention may be formulated as a single agent or as a combination of two or more agents. (C) The compounding amount of the ultraviolet absorber is 3 to 40% by mass, preferably 3 to 30% by mass, and more preferably 3 to 20% by mass, based on the total amount of the cosmetic. If the compounding amount of (A) the ultraviolet absorber is less than 3% by mass, it is difficult to obtain a sufficient ultraviolet protection effect. Even if it is compounded in an amount exceeding 40% by mass, an increase in the ultraviolet protection effect commensurate with the compounding amount cannot be expected, and on the contrary, it is not preferable in terms of deterioration of stability and usability.

[0041] Generally, in sunscreen cosmetics, ethylhexyl methoxycinnamate is often compounded to achieve a high SPF. In the sunscreen cosmetic of the present invention, since a high SPF can be achieved by compounding the (D) ultraviolet protection enhancing agent described below, the compounding amount of ethylhexyl methoxycinnamate may be 3% by mass or less or 1% by mass or less based on the total amount of the cosmetic. Furthermore, a high SPF can be obtained even without containing ethylhexyl methoxycinnamate.

[0042] The sunscreen cosmetic of the present invention can obtain a high ultraviolet protection effect only by compounding the (C) ultraviolet absorber, so it may not contain an ultraviolet scattering agent such as zinc oxide or titanium oxide. Therefore, the embodiments of the present invention include an embodiment in which the compounding amount of the ultraviolet scattering agent is 3% by mass or less or 1% by mass or less based on the total amount of the cosmetic, or an embodiment that does not contain an ultraviolet scattering agent. In the cosmetic of the present invention, by reducing the compounding amount of the ultraviolet scattering agent or not compounding the ultraviolet scattering agent, a transparent sunscreen cosmetic that does not cause whitening when applied to the skin can be obtained.

[0043] In the present invention, "transparent" means that no color, particularly white, is generated when the cosmetic is applied to the skin. Specifically, using an image colorimeter IMAGE COLORIMETER (manufactured by Asieda Design Office), the lightness (L value) calculated based on the direct reading method of stimulus values is obtained, and the difference (ΔL) between the lightness (L0) before application and the lightness (L * ) after application is 1.2 or less, preferably 0.65 or less, it is considered that the coating is transparent after application.

[0044] <(D) UV protection enhancer> The (D) UV protection enhancer of the present invention (hereinafter sometimes simply referred to as "component (D)") refers to a compound that has the function of improving or amplifying the UV protection of a UV absorber incorporated into a cosmetic composition according to the present invention. Specifically, it is a compound selected from the following components (D-1) and (D-2).

[0045] (D-1) Hydrophilic powder The (D-1) hydrophilic powder (hereinafter sometimes simply referred to as "(D-1) component") incorporated into the cosmetic composition according to the present invention is a substance commonly incorporated into cosmetics, whose particle surface is hydrophilic, and whose specific surface area is 190 m². 2 / g or more, preferably 190-800m 2 This refers to powdered ingredients measured in grams. Examples of powders constituting component (D-1) include silica (anhydrous silicic acid), cellulose, starch, talc, and mica. Among these, silica is preferred.

[0046] As component (D-1) of the present invention, commercially available products such as Sunsphere L-51S (manufactured by AGC SI-TEC), Godball E-6C (manufactured by Suzuki Oil & Fat Industry Co., Ltd.), and TMS-10 (manufactured by Teika Co., Ltd.) can also be used.

[0047] Among the components of (D-1) mentioned above, powders with an average particle size of 4 to 15 μm and an oil absorption amount of 120 to 250 ml / 100g, as measured according to JIS K5101-13-2 (boiled linseed oil method), exhibit particularly excellent UV protection enhancement effects. In this invention, the average particle size is the value measured as the volume-average particle size (D50) using a laser diffraction / scattering particle size distribution analyzer (MT3300EXII; Microtrac-Bell), after adding 0.05 g of powder to 20 g of ethanol solvent and performing ultrasonic dispersion for 1 minute using an ultrasonic homogenizer (US-150T; manufactured by Nippon Seiki Seisakusho).

[0048] As the (D-1) hydrophilic powder of the present invention, one type may be used alone, or two or more types may be used in combination. The amount of component (D-1) is preferably 1 to 10% by mass, more preferably 1 to 8% by mass, and even more preferably 1.5 to 6% by mass, relative to the total amount of cosmetic product. If the amount of component (D-1) is less than 1% by mass, the UV protection-enhancing effect of component (D-1) tends not to be fully realized, and if it exceeds 10% by mass, the usability may deteriorate.

[0049] (D-2) Oil phase thickener The (D-2) oil phase thickener (hereinafter sometimes simply referred to as "(D-2) 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. Specific 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.

[0050] 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.

[0051] 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.

[0052] 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, and hydrogenated avocado oil.

[0053] Organically modified clay minerals are a type of colloidal hydrated aluminum silicate with a three-layer structure, and are typically obtained by modifying clay minerals represented by the following formula (4) with a quaternary ammonium salt type cationic surfactant. (X,Y) 2-3 (Si,Al)4O 10 (OH)2Z 1 / 3 nH2O (4) However, X = Al, Fe(III), Mn(III), Cr(III), Y = Mg, Fe(II), Ni, Zn, Li, and Z = K, Na, Ca.

[0054] Specific examples of organically modified clay minerals include dimethyldistearylammonium hectorite (disteardimonium hectorite), dimethylalkylammonium hectorite, benzyldimethylstearylammonium hectorite, and magnesium aluminum silicate treated with distearyldimethylammonium chloride. Commercially available options 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.).

[0055] 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, isopalmitic acid, isostearic acid, linoleic acid, and linolenic 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.

[0056] In particular, it is preferable to use dextrin fatty acid ester as the (D-2) oil phase thickener of the present invention. As the (D-2) oil phase thickener of the present invention, one substance selected from the above substances may be used alone, or two or more substances may be used in combination.

[0057] (D-2) 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, a sufficient improvement in UV protection cannot be obtained, and even if the amount exceeds 10% by mass, it tends not to be possible to obtain a further increase in the effect.

[0058] In the present invention, the UV protection-enhancing effect obtained by component (D-1) or component (D-2) is an effect that is exerted without canceling out each other's effects. Therefore, when component (D-1) and component (D-2) are combined in a formulation, an additive effect is obtained in terms of UV protection-enhancing effect. Thus, there is an advantage to combining component (D-1) and component (D-2) in achieving a high SPF in sunscreen cosmetics.

[0059] In the cosmetic composition according to the present invention, emulsion stability can be further improved by incorporating (E) an anionic surfactant (hereinafter sometimes simply referred to as "(E) component") in addition to the components (A) to (D) above.

[0060] The (E) anionic surfactant incorporated into the cosmetic composition according to the present invention may be any surfactant commonly used in cosmetics, and is other than the (B) silicone-based surfactants such as polyoxyalkylene-modified silicones mentioned above, and refers to a surfactant having an anionic hydrophilic group such as a carboxylic acid, sulfonic acid, or phosphate structure. The incorporation of the anionic surfactant stabilizes the nanodiscs.

[0061] In particular, it is preferable to use an anionic surfactant with a Krafft point higher than room temperature. If the Krafft point of the anionic surfactant is lower than room temperature, the silicone-based surfactant and the anionic surfactant tend to mix and interact more easily, which tends to hinder the transfer from vesicles to nanodiscs.

[0062] As the (E) anionic surfactant incorporated into the cosmetic composition according to the present invention, a sulfonate-type anionic surfactant is preferred. Examples of sulfonate-type anionic surfactants include disulfosuccinate, alkylallyl sulfonate, alkyl ether sulfonate, sulfosuccinate, acylmethyltaurate, acyl taurate, potassium cetyl phosphate, and potassium cocoyl glutamate. Among these, it is preferable to select and use from acylmethyltaurate, potassium cetyl phosphate, and potassium cocoyl glutamate.

[0063] In the present invention, it is particularly preferable to incorporate an N-acylmethyl taurate as an anionic surfactant. Furthermore, among the N-acylmethyl taurates represented by the following formula (5), it is preferable to use an N-stearoyl-N-methyl taurate.

[0064] [ka]

[0065] Component (E) is a selective component in the cosmetic composition of the present invention and is not required to be included. However, if it is included, it must be in a favorable amount from the viewpoint of nanodisk stabilization. Examples include 0.01 to 1% by mass, 0.01 to 0.1% by mass, and 0.01 to 0.06% by mass relative to the total amount of the cosmetic composition. Furthermore, it is preferable that the ratio of (B) polyoxyalkylene-modified silicone to (E) anionic surfactant is 1:0.01 to 1:0.06 by mass.

[0066] The water used in the cosmetic composition according to the present invention can be selected as needed, such as ion-exchanged water, purified water, tap water, or natural water. The amount used is the remaining amount relative to the sum of the essential components and other optional components according to the present invention (mass %) of the total cosmetic composition. Generally, an amount of about 30 to 70% by mass relative to the total cosmetic composition is preferable.

[0067] In addition to the above-mentioned components, the oil-in-water emulsion cosmetic composition according to the present invention may contain, as necessary, any other additive components commonly used in topical skin preparations such as cosmetics and pharmaceuticals, to the extent that they do not impair the purpose and effects of the present invention. For example, oils other than component (C), polyhydric alcohols, nonionic surfactants, film-forming agents, astringents, chelating agents, pH adjusters, antioxidants, whitening agents, and other various agents, fragrances, etc. However, the invention is not limited to these examples.

[0068] The cosmetic composition according to the present invention may contain oils other than component (C) mentioned above. Examples of oils other than component (C) include hydrocarbon oils, ester oils, higher alcohols having 12 to 22 carbon atoms, and fats and oils.

[0069] Examples of hydrocarbon oils include hydrocarbons that are liquid at room temperature (25°C), such as liquid paraffin, isohexadecane, isododecane, squalane, squalene, pristane, paraffin, isoparaffin, hydrogenated polyisobutene, olefin oligomers, and volatile hydrocarbon oils (e.g., isododecane, isohexadecane, undecane, tridecane, etc.).

[0070] 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 di-2-ethylhexanoate, dipentaerythritol fatty acid ester, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, glyceryl di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, glyceryl triisostearate, pentaerythrityl tetraethylhexanoate, and tri Ethylhexanoin (glyceryl tri-2-ethylhexanoate), cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, glyceryl trimiristicate, glyceride tri-2-heptyl undecanoate, methyl castor oil fatty acid ester, oleyl oleate, cetostearyl alcohol, acetoglyceride, 2-heptyl undecyl palmitate, diisobutyl adipate, N-lauroyl-L-glutamic acid Examples include 2-octyldodecyl, di-2-heptylundecyl adipate, ethyl laurate, di-2-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.

[0071] Examples of higher alcohols with 12 to 22 carbon atoms include oleyl alcohol, 2-decyltetradecinol, dodecanol, isostearyl alcohol, and octyldodecanol.

[0072] Examples of oils and fats include Japanese wax, 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.

[0073] Since oils other than component (C) are selective ingredients in the cosmetic composition of the present invention, they do not necessarily have to be included. However, if they are included, it is preferable to include them in an amount that allows the effect of the inclusion to be recognized, and in a limit that does not cause adverse effects such as impairing the feel of use due to an excessive amount. The preferred amount of oils other than component (C) in the cosmetic composition of the present invention is about 1 to 30% by mass relative to the total amount of the cosmetic composition.

[0074] From the viewpoint of improving emulsification stability, in the cosmetic composition of the present invention, the amount of silicone oil is preferably 5% by mass or less, or 3% by mass or less, or more preferably 1% by mass or less, based on the total amount of the cosmetic composition. Furthermore, embodiments of the present invention include cosmetic compositions that substantially do not contain silicone oil.

[0075] The vesicles, which are precursors to the nanodiscs according to the present invention, can be produced as an aqueous vesicle dispersion by thoroughly mixing (B) polyoxyalkylene-modified silicone with (A) aqueous component, and then dropping the mixture dropwise into an aqueous phase containing aqueous components other than component (A) while stirring. The mixing state of (B) polyoxyalkylene-modified silicone and (A) aqueous component only needs to be confirmed to be transparent and in a single-phase state, which can be achieved, for example, by mixing at room temperature to 90°C for 1 to 30 minutes. By this method, vesicle particles with an average particle diameter of 30 to 150 nm, as measured by dynamic light scattering, can be obtained.

[0076] The vesicles according to the present invention can also be manufactured by conventional methods in which an oily component is retained within the bilayer film of the vesicle. Specifically, the vesicles according to the present invention may be manufactured in which an oil-soluble component such as a fragrance is added and mixed in the step of mixing (B) polyoxyalkylene-modified silicone and (A) aqueous component, thereby retaining the oil-soluble component within the bilayer film of the vesicle.

[0077] The oil-in-water emulsion cosmetic according to the present invention is stabilized by adding an oily component to an aqueous phase containing vesicles and dispersing it while applying strong stirring force, thereby forming a three-phase structure of aqueous phase-nanodisk phase-oil phase in which nanodisks (phase) transferred from the vesicles adhere to the oil phase (oil droplets). Therefore, the oil-in-water emulsion cosmetic composition according to the present invention is characterized in that nanodiscs made of (B) polyoxyalkylene-modified silicone are attached (localized) to the oil-water interface, that is, around oil droplets made of the oil phase. The major axis of the nanodiscs is 20 nm to 1000 nm.

[0078] The three-phase structure of aqueous phase-nanodisc phase-oil phase in the oil-in-water emulsion cosmetic according to the present invention can be formed by a conventional method. Specifically, under stirring, (B) polyoxyalkylene-modified silicone is dropped into (A) aqueous component to form vesicle particles and obtain a vesicle aqueous dispersion. An oily component, separately mixed and dissolved, is added to this vesicle aqueous dispersion and dispersed with strong stirring force, causing the vesicles to transfer to nanodiscs, resulting in a three-phase structure of aqueous phase-nanodisc phase-oil phase. In this case, if (E) an anionic surfactant is to be included, it is preferable to add it to the vesicle aqueous dispersion before adding the oily component. Since oil droplets consisting of the oily component are emulsified and dispersed in the aqueous phase, and nanodiscs are localized on the surface of the oil droplet particles, the emulsion stability is excellent, as is the feel on the skin (freshness, non-stickiness). The stirring device used for stirring is not particularly limited, and for example, a homomixer, disperser, etc., can be used.

[0079] In this invention, the vesicle particles formed in the aqueous phase can be molded to a sufficiently small particle size by applying strong shear using a homomixer or the like, and then uniformly dispersed in the aqueous phase. The degree of strong shear is not particularly limited, but is usually set to about 5 minutes at a homomixer speed of 7,000 to 12,000 revolutions per minute.

[0080] In the present invention, when an anionic surfactant (E) is incorporated, it is preferable to form vesicle particles in the aqueous phase, add the anionic surfactant (E) to the vesicle dispersion, and then add an oily component to emulsify it. Accordingly, the method for producing an oil-in-water emulsion cosmetic according to the present invention comprises: a vesicle-forming step of mixing (A) an aqueous component and (B) a polyoxyalkylene-modified silicone to form vesicles; optionally, a step of adding (E) an anionic surfactant to the vesicle dispersion obtained in the vesicle-forming step; and an emulsification step of emulsifying the mixture obtained in the above step with an oily component separately mixed and dissolved while applying stirring and shearing force.

[0081] In the vesicle formation step, (A) an aqueous component and (B) a polyoxyalkylene-modified silicone may be dissolved in advance, and the dissolved product may be mixed with the remaining aqueous phase component to obtain a vesicle dispersion in which vesicles are dispersed in the aqueous phase, or (B) a polyoxyalkylene-modified silicone may be mixed and stirred into an aqueous phase containing (A) an aqueous component and an aqueous component other than (A) to obtain a vesicle dispersion in which vesicles are dispersed in the aqueous phase.

[0082] The cosmetic composition according to the present invention has a refreshing feel characteristic of oil-in-water emulsions and exhibits excellent UV protection. Furthermore, the nanodisc-containing emulsion according to the present invention can contain a large amount of oil, which is not possible with conventional solubilizers, yet still provides a refreshing feel.

[0083] The cosmetic composition according to the present invention can be suitably used in various dosage forms such as cream, emulsion, and liquid. In terms of product form, it can be a skincare cosmetic such as sunscreen, or a makeup cosmetic such as a makeup base or foundation. [Examples]

[0084] 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.

[0085] <Improvement rate of UV protection> Each cosmetic sample was measured at a concentration of 2 mg / cm³ on a measurement plate (S plate) (5 x 5 cm V-groove PMMA plate, SPFMASTER-PA01). 2 The coating was dropped in the specified amount, applied with a finger for 60 seconds, and dried for 15 minutes. The absorbance of the formed coating was then measured using a U-3500 self-recording spectrophotometer (Hitachi, Ltd.). An uncoated plate was used as a control. The absorbance (Abs) was calculated using the following formula, and the measured values ​​from 280 nm to 400 nm were integrated to determine the absorbance at 310 nm. Abs = -log(T / To) T: Transmittance of the sample, To: Transmittance of the uncoated sample

[0086] The improvement rate of UV protection relative to the control sample was calculated from the absorbance of the obtained sample at 310 nm using the following formula. Note that in Examples 1-6, Comparative Examples 2-6, and the Reference Example shown in Table 1, Comparative Example 1, which does not contain component (D) of the present invention, was used as the control sample. [Improvement in UV protection (%)] = [Absorbance of each sample at 310 nm - Absorbance of the control sample at 310 nm] / [Absorbance of the control sample at 310 nm] × 100 A 0% improvement rate indicates no change in the increase or decrease in UV protection, while an improvement rate of 100% and 200% indicates that the UV protection of the sample increased by 100% and 200% of the UV protection of the target sample, respectively, meaning that the UV protection doubled and tripled, respectively.

[0087] (Examples and Comparative Examples) Sunscreen cosmetics having the compositions listed in Table 1 were prepared. Specifically, component (B) was added dropwise to component (A) under stirring, then an anionic surfactant and other aqueous components were mixed to obtain an aqueous phase solution. The oily components and powder components were separately mixed to obtain an oil phase solution, which was then mixed into the aqueous phase solution while stirring to obtain an oil-in-water emulsion cosmetic. The improvement rate of UV protection was evaluated for the prepared samples. The results are shown in the table. Note that "×" in the evaluation result column of the table indicates that the cosmetic could not be prepared.

[0088] [Table 1]

[0089] *1: Sunsphere L-51S (manufactured by AGC SI-TEC) *2: Godball E-6C (manufactured by Suzuki Oil & Fat Industry Co., Ltd.) *3: TMS-10 (manufactured by Teika Co., Ltd.) *4: Satinia M5 (manufactured by JGC Catalysts & Chemicals Co., Ltd.) *5: Chiffonsil P-3R (manufactured by JGC Catalysts & Chemicals Co., Ltd.)

[0090] As shown in Table 1, the (D-1) component of the present invention has a specific surface area of ​​190 m². 2 In the cosmetics of Examples 1 to 3, which contained silica of 1 / g or more, the UV protection was improved compared to the cosmetic of Comparative Example 1, which did not contain component (D) of the present invention. In particular, the cosmetic formulation containing silica with an average particle size of 4-15 μm and an oil absorption capacity of 120-250 ml / 100g (Example 1) showed a particularly excellent effect in improving UV protection. On the other hand, the specific surface area is 190 m² 2 In Comparative Example 2, the cosmetic formulation containing less than 1g of silica showed no improvement in UV protection, and in Comparative Example 3, almost no improvement in UV protection was observed.

[0091] Furthermore, the cosmetic composition of Example 6, which contains dextrin fatty acid ester as component (D-2) of the present invention, showed improved UV protection. On the other hand, even compounds generally classified as oil-phase thickeners, such as silicone waxes and waxes, were not suitable for the cosmetics of the present invention (Comparative Examples 5 and 6), and the cosmetic of Comparative Example 4, which contained an amino acid gelling agent, showed almost no improvement in UV protection.

[0092] The example cosmetic is an oil-in-water emulsion cosmetic using silicone nanodiscs, and is an example of a sunscreen cosmetic with a high SPF due to the combination of UV absorbers and UV scatterers. As shown in Examples 4 and 5, in the cosmetic composition of the present invention, when components (D-1) and (D-2) are combined as component (D), their respective UV protection-enhancing effects are exhibited, and a cosmetic composition with a high SPF comparable to that of the reference example can be obtained without the inclusion of a UV scattering agent.

Claims

1. (A) an aqueous component selected from monohydric alcohols and dihydric alcohols, (B) Polyoxyalkylene-modified silicone, (C) UV absorbers, and (D) At least one UV protection enhancer selected from the following: (D-1) Specific surface area of ​​190 m² ２ Hydrophilic powder of 1g or more (D-2) Dextrin fatty acid ester, an oil phase thickener Includes, The aqueous component (A) is 1 to 15% by mass of the total amount of cosmetic when it is a monohydric alcohol alone, 1 to 20% by mass of the total amount of cosmetic when it is a dihydric alcohol alone, and the total amount when it is a combination of a monohydric alcohol and a dihydric alcohol is 1 to 45% by mass of the total amount of cosmetic. If an ultraviolet scattering agent is included, its amount must be 3% by mass or less of the total amount of the cosmetic. An oil-in-water type sunscreen cosmetic in which nanodiscs made of the above-mentioned component (B) are attached to the oil-water interface.

2. Furthermore, the oil-in-water sunscreen cosmetic composition according to claim 1, further comprising (E) an anionic surfactant.

3. The oil-in-water sunscreen cosmetic composition according to claim 1 or 2, wherein the (B) component is PEG-12 dimethicone.

4. The oil-in-water type sunscreen cosmetic according to any one of claims 1 to 3, wherein the hydrophilic powder (D-1) is silica.

5. The oil-in-water sunscreen cosmetic composition according to any one of claims 1 to 4, wherein the (D) component comprises (D-1) a hydrophilic powder having a specific surface area of ​​190 m² / g or more and (D-2) an oil phase thickener which is a dextrin fatty acid ester.

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