Water emulsion

Abstract

The present invention provides an aqueous emulsion comprising: (1) terephthalylidene dicamphor sulfonic acid; (2) a phosphorus-free compound or a salt thereof having at least two hydroxyl groups and an alkyl group having 16 to 22 carbon atoms; and (3) a polysaccharide thickener containing glucose, glucuronic acid, and rhamnose as main chain constituent monosaccharides.

Description

[Technical field]

[0001] The present invention relates to a water-based emulsion, and in particular to an oil-in-water emulsion. [Background technology]

[0002] Ultraviolet rays include UV-A and UV-B. UV-B, which has a short wavelength (wave length: 280-320 nm), is mainly absorbed by the surface of the skin and is said to cause sunburn. On the other hand, UV-A, which has a longer wavelength than UV-B (wave length: 320-400 nm), is said to reach the dermis of the skin and cause suntan. The performance of sunscreens is generally evaluated by SPF (Sun Protection Factor) and PA (Protection grade of UVA). SPF indicates the degree of prevention effect against acute inflammation (sunburn) caused mainly by UV-B, and is displayed as SPF10, SPF20, SPF30, SPF40, SPF50, and SPF50+ depending on the degree of prevention. PA indicates the degree of UV-A prevention effect, and is displayed as PA+, PA++, PA+++, and PA++++ depending on the degree of prevention.

[0003] Sunscreens generally contain UV absorbers such as ethylhexyl methoxycinnamate (OMC) and oxobenzone, and UV scattering agents such as nano-TiO2 and nano-ZnO. In recent years, there has been a trend to reconsider the cosmetic ingredients used in sunscreens from the perspectives of environmental consideration, safety, sustainability, etc. However, it is not easy to realize a sunscreen formulation that achieves a high SPF / PA value and a comfortable texture while not using or reducing the amount of conventional UV absorbers and UV scattering agents.

[0004] TerephthalylideneDicamphorSulfonic Acid (TDSA) is a hydrophilic UV-A absorber that can replace common hydrophobic UV-A absorbers. Conventional sunscreen formulations require a large amount of oil phase to stably dissolve the hydrophobic UV absorber, but by replacing a part of this with hydrophilic TDSA, it is expected that the amount of oil phase can be reduced and a lighter, less greasy texture can be produced. Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, TDSA is a very strong acid with two sulfonic acid groups, which easily breaks down the emulsion system. Therefore, it is considered necessary to add a strong anionic surfactant to stabilize an emulsion system containing TDSA. However, strong anionic surfactants are very irritating to the skin. For example, sulfate-based surfactants also act as cleansing agents, so it is not preferable to incorporate them from the viewpoint of safety. Monoalkyl phosphate-type anionic surfactants are less irritating to the skin than other anionic surfactants, but they tend to promote the crystallization of TDSA over time. For these reasons, it is difficult to stabilize an emulsion system containing TDSA and achieve a light texture even with a small oil phase.

[0006] WO2020 / 163928A1 describes a sunscreen composition comprising a TDSA and a stable surfactant system comprising at least one anionic surfactant and at least one nonionic surfactant.

[0007] An object of the present invention is to provide an aqueous emulsion which contains terephthalylidene dicamphorsulfonic acid (TDSA) and has excellent stability. [Means for solving the problem]

[0008] The present invention provides an aqueous emulsion comprising: (1) terephthalylidene dicamphorsulfonic acid; (2) a phosphorus-free compound or a salt thereof having at least two hydroxyl groups and an alkyl group having 16 to 22 carbon atoms; and (3) a polysaccharide thickener containing glucose, glucuronic acid, and rhamnose as main chain constituent monosaccharides.

[0009] In the above aqueous emulsion, the component (2) may contain an organic acid monoglyceride and / or a salt thereof, and / or an alkyl glyceryl ether, and is particularly preferably glyceryl stearate citrate and / or a salt thereof. The content of the component (2) may be 0.1% to 10% by mass, preferably 0.2% to 8.0% by mass, and more preferably 0.3% to 5.0% by mass, based on the total amount of the aqueous emulsion.

[0010] In the above aqueous emulsion, the component (3) may contain a polysaccharide thickener further containing at least one selected from the group consisting of rhamnose, fucose, glucose, and mannose as a side chain constituent monosaccharide, and it is particularly preferable to contain at least one polysaccharide thickener selected from diutan gum, welan gum, gellan gum, and mixtures thereof. The content of the component (3) may be 0.01% to 2.0% by mass, preferably 0.02% to 1.5% by mass, and more preferably 0.05% to 1.0% by mass, based on the total amount of the aqueous emulsion.

[0011] The above-mentioned aqueous emulsion may further comprise an emulsifier other than component (2) selected from the group consisting of polyglycerol esters of fatty acids having 12 to 24 carbon atoms and having 2 to 12 glycerin units, glycerol esters of fatty acids having 12 to 24 carbon atoms, and combinations thereof, and may further comprise a thickener other than component (3) selected from the group consisting of (meth)acrylic polymers, cellulose-based thickeners, and combinations thereof.

[0012] In a specific embodiment, the above-mentioned aqueous emulsion further comprises a thickener other than the component (3), which is selected from the group consisting of a (meth)acrylic polymer, a cellulose-based thickener, and a combination thereof.

[0013] In certain preferred embodiments, the aqueous emulsion of the present invention is (1) Terephthalidene dicamphor sulfonic acid (2) organic acid monoglyceride and / or its salt, and / or alkyl glyceryl ether, preferably glyceryl citrate stearate and / or its salt, and (3) At least one thickening polysaccharide selected from the group consisting of diutan gum, welan gum, gellan gum, and combinations thereof. Includes.

[0014] In certain embodiments, the water-based emulsion may be an oil-in-water cosmetic, and may be a sunscreen.

[0015] Furthermore, the present invention also provides a cosmetic method for the care of keratinous materials, which comprises applying the aqueous emulsion of the present invention to keratinous materials, in particular to the skin. In particular, the aqueous emulsion of the present invention is for use as a sunscreen, in particular for use in preventing sunburn. Effect of the Invention

[0016] According to the present invention, it is possible to provide a water-based emulsion that has excellent UV protection effect and stability, and also has a light texture. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Preferred embodiments of the present invention will be described in detail below, however, the present invention is not limited to the following embodiments.

[0018] The aqueous emulsion of the present invention contains (1) terephthalylidene dicamphor sulfonic acid, (2) a phosphorus-free compound or a salt thereof having at least two hydroxyl groups and an alkyl group having 16 to 22 carbon atoms, and (3) a polysaccharide thickener containing glucose, glucuronic acid, and rhamnose as main chain constituent monosaccharides.

[0019] The aqueous emulsion according to this embodiment has excellent UV protection effect and a light texture due to the inclusion of terephthalylidene dicamphorsulfonic acid (TDSA), a water-soluble UV absorber, and furthermore, excellent stability is provided by components (2) and (3).

[0020] <(1) Ingredients> The aqueous emulsion according to the present embodiment contains terephthalylidene dicamphorsulfonic acid as component (1). In the aqueous emulsion according to the present embodiment, component (1) serves as an ultraviolet absorbing agent.

[0021] Terephthalylidene dicamphor sulfonic acid (common name: Ecamsule) (bicyclo[2.2.1]heptane-1-methanesulfonic acid, 3,3'-(1,4-phenylenedimethylidyne)bis[7.7]-dimethyl-2-oxo) is a water-soluble benzylidene camphor derivative, an organic compound that absorbs UV-A (maximum absorption wavelength: 345 nm). Terephthalylidene dicamphor sulfonic acid has been reported to have almost no skin penetration and almost no primary skin irritation, making it safe for the human body. Terephthalylidene dicamphor sulfonic acid is commercially available, for example, as Mexoryl SX (Chimex).

[0022] Terephthalylidene dicamphorsulfonic acid may be in the form of a salt, for example, an inorganic salt such as a sodium salt, a potassium salt, a calcium salt, a magnesium salt, etc., or an organic salt such as a methylamine salt, a dimethylamine salt, etc., with the sodium salt being preferred.

[0023] In the aqueous emulsion according to the present embodiment, the content of the component (1) may be, for example, 0.01% by mass or more, 0.05% by mass or more, or 0.10% by mass or more, and 15% by mass or less, 14% by mass or less, 13% by mass or less, 12% by mass or less, 11% by mass or less, or 10% by mass or less, based on the total amount of the aqueous emulsion. In particular, the content of the component (1) may be in the range of 0.01% by mass to 15% by mass, particularly 0.05% by mass to 12% by mass, or 0.10% by mass to 10% by mass, and most preferably 0.5% by mass to 5% by mass, based on the total amount of the aqueous emulsion.

[0024] <(2) Ingredients> The aqueous emulsion of the present invention contains, as component (2), a phosphorus-free compound having at least two hydroxyl groups and an alkyl group having 16 to 22 carbon atoms, or a salt thereof.

[0025] The component (2) is an amphiphilic substance having a hydrophilic portion and a lipophilic portion in the molecule of the compound. In the aqueous emulsion according to the present embodiment, the component (2) acts as an emulsifier, thereby stabilizing the aqueous emulsion and preventing the crystallization of the component (1).

[0026] In certain embodiments, the alkyl group contained in the compound of component (2) has a carbon number of 16 to 20 or 16 to 18. Component (2) may have, for example, 2, 3, 4, 5, or 6 hydroxyl groups per molecule.

[0027] The component (2) is a compound that does not have a phosphorus atom. The present inventors have found that when a monoalkyl phosphate is used among amphiphilic polymer surfactants, rapid crystallization of terephthalylidene dicamphor sulfonic acid occurs in the resulting emulsion. The component (2) is preferably a compound consisting of carbon atoms, hydrogen atoms, and oxygen atoms, or a salt thereof. The component (2) may be an anionic surfactant.

[0028] In a specific embodiment, component (2) may include, for example, an organic acid monoglyceride and / or a salt thereof, and / or an alkyl glyceryl ether. In a specific embodiment, component (2) preferably includes an organic acid monoglyceride and / or a salt thereof, and particularly preferably includes glyceryl citrate stearate and / or a salt thereof.

[0029] The organic acid monoglyceride may be, for example, a monoester of an organic acid and an ester of a fatty acid having 16 to 22 carbon atoms with glycerin. The organic acid in the organic acid monoglyceride may be, for example, an aliphatic hydroxy acid such as citric acid. Examples of the salt include inorganic salts such as sodium salt, potassium salt, calcium salt, magnesium salt, and organic salts such as methylamine salt, dimethylamine salt, and sodium salt is preferred. In a specific embodiment, examples of the organic acid monoglyceride or salt thereof having at least two hydroxyl groups and an alkyl group having 16 to 22 carbon atoms and no phosphorus atom include glyceryl citrate stearate, glyceryl succinate, and salts thereof.

[0030] The alkyl glyceryl ether may have, for example, two hydroxyl groups. Examples of alkyl glyceryl ethers having at least two hydroxyl groups and an alkyl group having 16 to 22 carbon atoms and no phosphorus atom include batyl alcohol, chimyl alcohol, and selachyl alcohol.

[0031] In the aqueous emulsion according to the present embodiment, the (2) component may be used alone or in combination of two or more. The total content of the (2) component may be, for example, 0.1% by mass or more, 0.2% by mass or more, 0.3% by mass or more, 0.4% by mass or more, 0.5% by mass or more, or 0.6% by mass or more, and may be 3.0% by mass or less, 2.5% by mass or less, 2.2% by mass or less, 2.0% by mass or less, 1.8% by mass or less, 1.7% by mass or less, 1.6% by mass or less, 1.5% by mass or less, 1.4% by mass or less, or 1.3% by mass or less, based on the total amount of the aqueous emulsion. In a specific embodiment, the total content of the (2) component may be in the range of 0.1% by mass to 10% by mass, particularly 0.2% by mass to 8.0% by mass or 0.3% by mass to 5.0% by mass, based on the total amount of the aqueous emulsion.

[0032] <(3) Ingredients> The aqueous emulsion of the present invention contains, as component (3), a polysaccharide thickener containing glucose, glucuronic acid, and rhamnose as main chain constituent monosaccharides. By containing the polysaccharide thickener as component (3), the aqueous emulsion can have high stability at high temperatures while maintaining a suitable viscosity.

[0033] The (3) component may include, for example, a polysaccharide thickener having a main chain in which structural units consisting of glucose, glucuronic acid, glucose, and rhamnose are linearly bonded in this order. The (3) component polysaccharide thickener may further have a side chain as a part of the polysaccharide structure, or may not have a side chain. In a specific embodiment, the side chain may have at least one monosaccharide selected from the group consisting of rhamnose, fucose, glucose, and mannose as a side chain constituent monosaccharide. The polysaccharide thickener may have a main chain in which structural units consisting of glucose, glucuronic acid, glucose, and rhamnose are linearly bonded in this order, and may have rhamnose as a side chain. The polysaccharide thickener may be derived from a microorganism such as a bacterium.

[0034] In a specific embodiment, the polysaccharide thickener comprises at least one selected from diutan gum, welan gum, and gellan gum. Preferably, the polysaccharide thickener is diutan gum. Diutan gum (INCI: Sphingomonas ferment extract) is a polysaccharide obtained by aerobic fermentation of corn syrup using a microorganism of the genus Alcaligenes.

[0035] In the aqueous emulsion according to the present embodiment, the (3) component may be used alone or in combination of two or more. The content of the (3) component may be, for example, 0.01% by mass or more, 0.02% by mass or more, 0.03% by mass or more, 0.04% by mass or more, 0.05% by mass or more, 0.06% by mass or more, or 0.07% by mass or more, and 1.0% by mass or less, 0.8% by mass or less, 0.6% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, 0.2% by mass or less, 0.15% by mass or less, or 0.1% by mass or less, based on the total amount of the aqueous emulsion. In particular, the total content of the (3) component is in the range of 0.01% by mass to 2.0% by mass, particularly 0.05% by mass to 1.5% by mass or 0.05% by mass to 1.0% by mass, based on the total amount of the aqueous emulsion. The aqueous emulsion according to this embodiment has excellent high-temperature stability even when a small amount of thickener is used.

[0036] <UVフィルタ> In a specific embodiment, the water-based emulsion may contain a UV filter other than the component (1). The UV filter may contain an organic UV filter (organic ultraviolet ray absorber) or an inorganic UV filter (inorganic ultraviolet ray absorber). The organic UV filter may be a lipophilic organic UV filter (lipophilic organic ultraviolet ray absorber) or a hydrophilic organic UV filter (hydrophilic organic ultraviolet ray absorber), which respectively include a UV-A absorber, a UV-B absorber, and a UV-A and UV-B absorber.

[0037] The term "oleophilic organic UV filter" refers to the organic UV filter that is used at room temperature (25°C) and atmospheric pressure (10 5 "UV filters" refers to organic UV filters that are soluble in oil at a concentration of at least 1% by weight (in Pa) based on the total weight of the oil.

[0038] The lipophilic organic UV-A absorbers include aminobenzophenone compounds, dibenzoylmethane compounds, anthranilic acid compounds, and 4,4-diarylbutadiene compounds. The aminobenzophenone compounds include diethylaminohydroxybenzoylhexylbenzoate (DHHB, trade name: UVinul A+, manufactured by BASF) and mixtures thereof. The dibenzoylmethane compounds include 4-isopropyldibenzoylmethane (trade name: Eusolex 8020, manufactured by Merck), 1-(4-methoxy-1-benzofuran-5-yl)-3-phenylpropane-1,3-dione (trade name: Pongamol, manufactured by Quest), 1-(4-(tert-butyl)phenyl)-3-(2-hydroxyphenyl)propane-1,3-dione, and butylmethoxydibenzoylmethane (trade name: Parsol 1789, manufactured by DSM). The anthranilic acid compounds include menthyl anthranilate (trade name: NEO HELIPAN MA Symrise) and mixtures thereof. The 4,4-diarylbutadiene compounds include 1,1-dicarboxy(2,2'-dimethylpropyl)-4,4-diphenylbutadiene, diphenylbutadiene malonic acid ester, malononitrile, and mixtures thereof.

[0039] Lipophilic organic UV-B filters include cinnamate compounds, salicylic acid compounds, anilinotriazine compounds, benzoic acid compounds, diphenylacrylate compounds, benzylidene camphor compounds, phenylbenzimidazole compounds, imidazoline compounds, benzalmalonic acid compounds, mecocyanine compounds and mixtures thereof.

[0040] Cinnamate compounds include ethylhexyl methoxycinnamate (trade name: PARSOL CX DSM), isopropyl ethoxycinnamate, and isoamyl methoxycinnamate (trade name: NEO HELIOPAN E 1000, Symrise), diisopropyl methylcinnamate, cinoxate, glyceryl dimethoxycinnamate octanoate, octyl cinnamate, isopropyl ethyl cinnamate, diisopropyl ethyl cinnamate, methyl diisopropyl cinnamate, propyl methoxycinnamate, isopropyl methoxycinnamate, isoamyl methoxycinnamate, octyl methoxycinnamate, cyclohexyl methoxycinnamate, ethyl-α-cyano-β-phenylcinnamate, 2-ethylhexyl-α-cyano-β-phenylcinnamate, glyceryl mono-2-ethylhexanoyl-di-para-methoxycinnamate, 3-methyl-4-[methylbis(trimethylsiloxy)silyl]butyl 3,4,5-trimethoxycinnamate, and mixtures thereof.

[0041] Salicylic acid compounds include ethylhexyl salicylate (trade name: NEO HELIOPAN OS, manufactured by Symrise), homosalate (trade name: EusolexHMS by Rona / EM Industries), amyl salicylate, menthyl salicylate, homomenthyl salicylate, octyl salicylate, phenyl salicylate, benzyl salicylate, p-isopropanol phenyl salicylate, and mixtures thereof.

[0042] Examples of the anilinotriazine compounds include trisanilinotriazine compounds such as ethylhexyl triazone (trade name: UVINUL T-150, manufactured by BASF), 2,4,6-tris(dineopentyl 4'-aminobenzalmalonate)-s-triazine and 2,4,6-tris(diisobutyl 4'-aminobenzalmalonate)-s-triazine, and bis-anilinotriazine compounds such as diethylhexylbutamidotriazine (trade name: UVASORB HEB, manufactured by SIGMA2V), and mixtures thereof.

[0043] Benzoic acid compounds include para-aminobenzoates (PABA), such as ethyl PABA (para-aminobenzoate), ethyl dihydroxypropyl PABA, ethylhexyl dimethyl PABA, PABA monoglycerin ester, N,N-dipropoxy PABA ethyl ester, N,N-diethoxy PABA ethyl ester, N,N-dimethyl PABA ethyl ester, and N,N-dimethyl PABA butyl ester, and mixtures thereof.

[0044] Diphenyl acrylate compounds include octylene (trade name: UVINUL N539, manufactured by BASF) and etrocrylene (trade name: UVINUL N35, manufactured by BASF). Benzylidene camphor compounds include 3-benzylidene camphor (trade name: MEXORYL SD, manufactured by CHIMEX), methyl benzylidene camphor (trade name: EUSOLEX 6300, manufactured by MERCK), polyacrylamide methyl benzylidene camphor (trade name: MEXORYL SW, manufactured by CHIMEX), and mixtures thereof.

[0045] Phenylbenzimidazole compounds include phenylbenzimidazole sulfonic acid (trade name: Eusolex 232, manufactured by Merck). Imidazoline compounds include ethylhexyl dimethoxybenzylidene dioxoimidazoline propionate. Benzalmalonic acid compounds include, for example, polysilicone-15 (trade name: Parsol SLX, manufactured by DSM) and polyorganosiloxanes containing benzalmalonic acid moieties such as dineopentyl 4'-methoxybenzalmalonic acid, and mixtures thereof.

[0046] The lipophilic UV-A and UV-B filters include benzophenone compounds such as benzophenone-1 (trade name: UVINUL 400, manufactured by BASF), benzophenone-2 (trade name: UVINUL 500, manufactured by BASF), benzophenone-3 (trade name: UVINUL M40, manufactured by BASF), benzophenone-6 (trade name: Helisorb 11, manufactured by Norquay), benzophenone-8 (trade name: Spectra-Sorb UV-24, manufactured by American Cyanamid), benzophenone-10, benzophenone-11 and benzophenone-12; benzoyl compounds such as dolomitrizole trisiloxane (trade name: Silatrizole, manufactured by Rhodia Chimie) and bumetrizole (trade name: TINOGUARTD AS, manufactured by CIBA); bis-ethylhexyloxyphenol methoxyphenyl triazine (trade name: TINOSORB S, manufactured by CIBA), bisresorcinyltriazine compounds; 2,4-bis[5-(1-dimethylpropyl)benzoxazol-2-yl(4-phenyl)imino]-6-(2-ethylhexyl)imino-1,3,5-triazine (trade name: Uvasorb K2A, manufactured by Sigma3V), and other benzoxazole compounds, and mixtures thereof.

[0047] The organic UV absorber may include a hydrophilic organic UV absorber. The term "hydrophilic organic UV filter" refers to a UV absorber that is absorbed at room temperature (25° C.) and atmospheric pressure (10 5 "Hydrophilic organic UV filters" refers to organic UV filters that are soluble in water at a concentration of at least 1% by weight, based on the total weight of water, in water at a concentration of at least 1% by weight (at 100 Pa). Aqueous dispersions of lipophilic organic UV filters in water can also be considered hydrophilic organic UV filters.

[0048] Hydrophilic organic UV-A filters include bisbenzoxazolyl derivatives such as terephthalylidene dicamphorsulfonic acid and its salts (trade name: Mexoryl SX, manufactured by Chimex) and disodium phenyl dibenzimidazole tetrasulfonic acid and its salts (trade name: Neo Heliopan AP, manufactured by Haarmann and Reimer), and mixtures thereof.

[0049] Hydrophilic organic UV-B filters include p-aminobenzoic acid (PABA), PABA derivatives such as glyceryl PABA and PEG-25 PABA and their salts (e.g., Uvinul P25 manufactured by BASF), benzimidazole sulfonic acid compounds such as phenylbenzimidazole sulfonic acid and their salts (e.g., Eusolex 232 manufactured by Merck), ferulic acid and its salts, salicylic acid and its salts, DEA methoxycinnamate and its salts, benzylidene camphorsulfonic acid and its salts (e.g., Mexoryl SL manufactured by Chimex) and camphorbenzalkonium methosulfate and its salts (e.g., Mexoryl SO manufactured by Chimex), and mixtures thereof.

[0050] Examples of aqueous dispersions of lipophilic organic UV filters include aqueous dispersions of lipophilic UV-A and UV-B filters, such as aqueous dispersions of alkylene bisbenzotriazolyl phenol compounds, such as methylene bisbenzotriazolyl tetramethylbutyl phenol (trade name: TINOSORB M, manufactured by BASF).

[0051] Hydrophilic organic UV-A and UV-B filters include benzophenone-4 and its salts (for example, trade name: Uvinul MS40, manufactured by BASF), benzophenone-5 and its salts, benzophenone-9 and its salts, and mixtures thereof.

[0052] The UV filter may contain an inorganic UV filter (ultraviolet ray scattering agent). The ultraviolet ray scattering agent may be fine particles having an average primary particle size of 1 nm to 50 μm, preferably 5 nm to 500 nm, and more preferably 10 nm to 200 nm. The average primary particle size is based on the arithmetic mean particle size.

[0053] The ultraviolet scattering agent is preferably a hydrophilically treated or untreated metal oxide, such as titanium oxide or zinc oxide.

[0054] The total content of the ultraviolet absorbers other than the component (1) can be 2 to 50 mass % based on the total amount of the aqueous emulsion, and may be 5 to 40 mass %, 10 to 25 mass %, or 10 to 20 mass %.

[0055] <Emulsifier> In a specific embodiment, the water-based emulsion may contain an emulsifier other than component (2). The emulsifier may be a nonionic emulsifier (nonionic surfactant).

[0056] Nonionic surfactants may include, for example, esters of a fatty acid and polyglycerol (polyglycerol fatty acid esters), esters of a fatty acid and glycerol (glycerol fatty acid esters), and mixtures thereof.

[0057] In a specific embodiment, the polyglycerol fatty acid ester may be a polyglycerol ester of a fatty acid having 12 to 24 carbon atoms, preferably 16 to 22 carbon atoms, more preferably 16 to 20 carbon atoms, and particularly preferably 18 carbon atoms. Examples of the constituent fatty acids include palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, α-linolenic acid, γ-linolenic acid, isostearic acid, arachidic acid, arachidonic acid, and behenic acid. The fatty acid may be saturated or unsaturated, and is preferably saturated. The glycerol unit (also referred to as the degree of polymerization of glycerol) contained in the polyglycerol fatty acid ester may be, for example, 2 to 12, preferably 2 to 10, more preferably 2 to 8, and particularly preferably 2 or 6.

[0058] In certain embodiments, the polyglycerol fatty acid ester is selected from the group consisting of, for example, polyglyceryl-2 stearate, polyglyceryl-2 isostearate, polyglyceryl-2 oleate, polyglyceryl-6 stearate, polyglyceryl-6 behenate, and mixtures thereof.

[0059] In a particular embodiment, the glycerin fatty acid ester may be a glycerin ester of a fatty acid having 12 to 24 carbon atoms, preferably 16 to 22 carbon atoms, more preferably 16 to 20 carbon atoms, and particularly preferably 18 carbon atoms. Examples of fatty acids include palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, α-linolenic acid, γ-linolenic acid, arachidic acid, arachidonic acid, and behenic acid. The fatty acid may be saturated or unsaturated, and is preferably saturated. In a particular embodiment, the glycerin fatty acid ester is, for example, selected from the group consisting of glyceryl stearate, glyceryl oleate, glyceryl myristate, glyceryl coconutate, glyceryl undecylenate, and mixtures thereof.

[0060] It is preferable that all emulsifiers other than component (2) are solid at room temperature (e.g., 25°C). In a specific preferred embodiment, the emulsifier other than component (2) is preferably selected from the group consisting of polyglycerol esters of fatty acids having 12 to 24 carbon atoms and 2 to 12 glycerin units, glycerol esters of fatty acids having 12 to 24 carbon atoms, and combinations thereof, and more preferably selected from polyglycerol esters of fatty acids having 12 to 24 carbon atoms and 2 to 12 glycerin units. Examples of emulsifiers other than component (2) include polyglyceryl-6 stearate and polyglyceryl-6 behenate. A commercially available product containing a combination of polyglyceryl-6 stearate and polyglyceryl-6 behenate is, for example, TEGO CARE PBS 6 (Evonik Operations GmbH).

[0061] In a specific embodiment, the total content of the emulsifiers other than the component (2) may be, for example, 0.1% by mass or more, 0.2% by mass or more, 0.5% by mass or more, 0.7% by mass or more, 1.0% by mass or more, or 1.2% by mass or more, and may be 10% by mass or less, 8% by mass or less, 6% by mass or less, 5% by mass or less, 4% by mass or less, 3% by mass or less, 2.5% by mass or less, 2.2% by mass or less, or 2% by mass or less, based on the total amount of the aqueous emulsion. In particular, the content of the emulsifiers other than the component (2) is in the range of 0.5% by mass to 10% by mass, particularly 0.5% by mass to 5% by mass, and preferably 1% by mass to 3% by mass, based on the total amount of the aqueous emulsion.

[0062] <Thickener> In a specific embodiment, the aqueous emulsion contains a thickener other than component (3). Examples of the thickener other than component (3) include (meth)acrylic polymers, cellulose-based thickeners, polysaccharide thickeners such as xanthan gum or dehydroxanthan gum, and the like, and are selected from the group consisting of (meth)acrylic polymers, cellulose-based thickeners, and combinations thereof.

[0063] The (meth)acrylic polymer may be a polymer obtained by polymerizing at least one monomer selected from the group consisting of (meth)acrylic acid and (meth)acrylic acid esters. The (meth)acrylic acid ester is not particularly limited, and examples thereof include alkyl (meth)acrylic acid esters and alkyl (meth)acrylic acid esters in which the alkyl group is substituted with a substituent such as a hydroxyl group, and the like, with alkyl (meth)acrylic acid esters being preferred. Examples of the alkyl (meth)acrylic acid esters include alkyl (meth)acrylic acid esters having an alkyl group with 10 to 30 carbon atoms and alkyl (meth)acrylic acid esters having an alkyl group with 1 to 9 carbon atoms, with alkyl (meth)acrylic acid esters having an alkyl group with 10 to 30 carbon atoms being preferred. The (meth)acrylic polymer may be a copolymer of at least one monomer selected from the group consisting of (meth)acrylic acid and alkyl (meth)acrylic acid esters having an alkyl group with 1 to 9 carbon atoms and at least one monomer selected from the group consisting of alkyl (meth)acrylic acid esters having an alkyl group with 10 to 30 carbon atoms.

[0064] The (meth)acrylic polymer may contain a structural unit derived from (meth)acrylic acid. Here, the structural unit derived from (meth)acrylic acid refers to a structural unit obtained by radical addition polymerization of (meth)acrylic acid. Note that the structural unit obtained by radical addition polymerization may have the same chemical structure as the structural unit obtained by radical addition polymerization, and may actually be a structural unit obtained by a method other than radical addition polymerization.

[0065] The (meth)acrylic polymer may be crosslinked. Examples of the crosslinking agent include a compound having a plurality of ethylenically unsaturated groups in the molecule, and may be a compound having a plurality of allyl ether groups in the molecule. Specific examples of the crosslinking agent include pentaerythritol allyl ether, sucrose allyl ether, propylene allyl ether, and allyl ether of sucrose. The (meth)acrylic polymer may be crosslinked with one or more crosslinking agents.

[0066] When the (meth)acrylic polymer has a carboxy group, at least a part of the carboxy group may be neutralized. In this specification, the carboxy group includes both a COOH group and a group in which the COOH is neutralized. When the carboxy group is neutralized, the counter cation of the carboxylate anion is not particularly limited, and examples thereof include alkali metal ions such as sodium ion and potassium ion, ammonium ion, and organic ammonium ion.

[0067] The (meth)acrylic polymer may contain a carbomer. As the component (B), commercially available products may be used, such as Carbopol (trademark) Ultrez 30 Polymer, Carbopol (trademark) Ultrez 10, Carbopol (trademark) ETD 2020, Carbopol (trademark) Ultrez 20 Polymer, and Pemulen TR-1, all of which are manufactured by Lubrizol, Aristoflex (trademark) AVC, and Simulgel (trademark) NS MB, all of which are manufactured by Seppic SA.

[0068] In a specific embodiment, the aqueous emulsion contains a cellulose-based thickener. Examples of the cellulose-based thickener include ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose, hydroxypropyl methylcellulose stearoxy ether, cellulose gum, carboxymethyl cellulose, and mixtures thereof. In a specific embodiment, the cellulose-based thickener preferably has an alkyl group having 10 to 30 carbon atoms, from the viewpoint of further increasing the high-temperature stability of the aqueous emulsion and further suppressing stickiness. In a specific preferred embodiment, an example of the cellulose-based thickener having an alkyl group having 10 to 30 carbon atoms is hydroxypropyl methylcellulose stearoxy ether.

[0069] <Oil> In a specific embodiment, the water-based emulsion of the present invention contains an oil agent in addition to the (1), (2), and (3) components. The oil agent may be, for example, a liquid oil or a paste oil. The liquid oil may be a non-polar liquid oil or a polar liquid oil. Examples of the liquid oil include coconut caprylate / caprate, squalane, sunflower oil, dimethicone, meadowfoam oil, almond oil, polyglyceryl-2 triisostearate, tri(caprylate / caprate)glyceryl, isotridecyl isononanoate, isononyl isononanoate, ethylhexyl palmitate, pentaerythrityl tetraethylhexanoate, pentaerythrityl tetraisostearate, cetyl ethylhexanoate, diisopropyl sebacate, tritridecyl trimellitate, hydrogenated polydecene, hydrogenated polyisobutene, and mixtures thereof.

[0070] The content of the oil agent relative to the total amount of the aqueous emulsion may be, for example, 3% by mass or more, 5% by mass or more, 8% by mass or more, 10% by mass or more, 12% by mass or more, 14% by mass or more, or 16% by mass or more, and may be 40% by mass or less, 30% by mass or less, 20% by mass or less, 18% by mass or less, 17% by mass or less, 15% by mass or less, 13% by mass or less, or 10% by mass or less. In particular, the content of the oil agent is in the range of 3% by mass to 50% by mass, particularly 5% by mass to 45% by mass, relative to the total amount of the aqueous emulsion.

[0071] The content of the liquid oil relative to the total amount of the aqueous emulsion may be, for example, 3% by mass or more, 5% by mass or more, 7% by mass or more, 8% by mass or more, 10% by mass or more, 12% by mass or more, or 14% by mass or more, and 40% by mass or less, 30% by mass or less, 20% by mass or less, 18% by mass or less, 17% by mass or less, 15% by mass or less, 13% by mass or less, 10% by mass or less, or 8% by mass or less. In particular, the content of the liquid oil is in the range of 3% by mass to 50% by mass, particularly 5% by mass to 45% by mass, relative to the total amount of the aqueous emulsion.

[0072] <Moisturizer> In a specific embodiment, the aqueous emulsion may contain a moisturizer in addition to the components (1), (2), and (3). Examples of the moisturizer include polyhydric alcohols having 3 to 5 carbon atoms. The polyhydric alcohol may have, for example, two or three alcoholic hydroxyl groups. Examples of the polyhydric alcohols having 3 to 5 carbon atoms include glycerin, 1,3-butylene glycol, pentylene glycol, propanediol, and mixtures thereof.

[0073] The content of the polyhydric alcohol having 3 to 5 carbon atoms may be, for example, 2% by mass or more, 5% by mass or more, 8% by mass or more, 10% by mass or more, 12% by mass or more, 15% by mass or more, 18% by mass or more, or 20% by mass or more, and may be 30% by mass or less, 28% by mass or less, 25% by mass or less, 23% by mass or less, 20% by mass or less, 18% by mass or less, or 15% by mass or less, based on the total amount of the aqueous emulsion. In particular, the content of the polyhydric alcohol having 3 to 5 carbon atoms is in the range of 2% by mass to 30% by mass, particularly 4% by mass to 30% by mass, based on the total amount of the aqueous emulsion.

[0074] <Other ingredients> In certain embodiments, the water-based emulsion may contain additives commonly used in cosmetics, such as pH adjusters, fragrances, preservatives, active ingredients, antioxidants, whitening agents, pigments, colorants, anti-inflammatory agents, anti-acne agents, skin conditioning agents, and mixtures thereof. In certain embodiments, the water-based emulsion contains an active ingredient, particularly an anti-inflammatory agent.

[0075] The pH of the aqueous emulsion according to this embodiment may be, for example, 5-9 or 6-8, and a pH of 7-8 is particularly preferred.

[0076] In certain embodiments, the aqueous emulsion may have a viscosity measured at 25° C. of, for example, 500 to 10,000 mPa·s, 700 to 9,000 mPa·s, or 700 to 8,000 mPa·s. The viscosity can be measured by shear viscosity measurement using a rotational viscometer (e.g., Rheolab QC; manufactured by Anton Paar; spindle: ST-22-4V-40; rotation speed: 100 rpm). The aqueous emulsion according to this embodiment has a relatively low viscosity and a light texture.

[0077] In a specific embodiment, the aqueous emulsion of the present invention is an oil-in-water type. The aqueous emulsion of the present invention contains water. The total content of water relative to the total amount of the aqueous emulsion may be, for example, 30% by mass or more, 35% by mass or more, 45% by mass or more, 47% by mass or more, 49% by mass or more, 51% by mass or more, 53% by mass or more, 55% by mass or more, 58% by mass or more, 60% by mass or more, or 61% by mass or more, and may be 70% by mass or less, 65% by mass or less, 63% by mass or less, 61% by mass or less, 59% by mass or less, or 57% by mass or less. In particular, the total content of water is in the range of 30% by mass to 70% by mass, particularly 35% by mass to 65% by mass, relative to the total amount of the aqueous emulsion.

[0078] In a specific embodiment, the aqueous emulsion of the present invention can be produced, for example, by mixing and emulsifying the (1) component, the (2) component, the (3) component, other thickeners, oils, emulsifiers, water, etc., while heating them to 80 to 85°C, and then cooling them to room temperature and mixing with the other components.

[0079] In certain embodiments, the aqueous emulsion of the present invention is in the form of, for example, a cream, a milky lotion, etc. The aqueous emulsion may be an oil-in-water-type emulsion cosmetic, in particular a sunscreen.

[0080] The oil-in-water emulsion cosmetic of a particular embodiment has excellent long-term storage stability (for example, no phase separation even when stored at 45° C. for 3 months). The sunscreen of a particular embodiment may have an ultraviolet ray shielding ability of SPF30, SPF40, SPF50, or SPF50+, and it is particularly preferable that the sunscreen has an ultraviolet ray shielding ability of SPF50+.

[0081] <Applications / methods> The present invention also provides a cosmetic method for the care of keratinous materials, which comprises applying the aqueous emulsion of the present invention to keratinous materials, in particular to the skin.

[0082] The present invention also provides an aqueous emulsion as described above for use as a sunscreen.

[0083] The present invention further provides an aqueous emulsion as described above for use in sun protection.

[0084] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. EXAMPLES

[0085] [Preparation of aqueous emulsion] The aqueous emulsions of Examples 1 to 5 and Comparative Examples 1 to 8 were prepared with the ingredients and blending ratios shown in Tables 1 to 3. The "%" in Tables 2 and 3 is all weight %. The ingredients of Phase A were dissolved at 80°C. The ingredients of Phases D1 and D2 were dissolved at room temperature. 0.5 to 1.0 kg of emulsion was prepared using a RAYNERI. The ingredients of Phase B were added to a tank and the tank was heated to 80°C. After the bulk in the tank became uniform, the ingredients of Phase C were added to the tank and mixed at 500 rpm until swollen. Phase A was then gradually added to the tank while mixing at 1,500 rpm. The mixture was emulsified with a RAYNERI for 5 minutes at 80°C, and then emulsified with a Turrax for 1 minute (10,000 rpm) at room temperature. The mixture was air-cooled to 30°C, and the ingredients of the remaining phases were added in order. The aqueous emulsions of Examples 1 to 5 and Comparative Examples 1 to 8 were obtained.

[0086] [Table 1]

[0087] [Table 2]

[0088] [Table 3]

[0089] [evaluation] The stability of the resulting emulsions was evaluated by the following method. The pH of all emulsions was just over 7. The viscosity was measured by shear viscosity measurement at 25°C using a rotational viscometer (Rheolab QC; manufactured by Anton Paar; spindle: ST-22-4V-40; rotation speed: 100 rpm).

[0090] 30 g of the emulsion was placed in a transparent container (50 mL). The glass bottle was capped and sealed. The glass bottle was stored at a constant temperature of 45°C. After standing for 3 months, it was visually observed whether phase separation had occurred. The results are shown in Tables 2 and 3. In the tables, "Stable" indicates that no phase separation was observed, and "Aqueous exudate" indicates that separation of the aqueous phase was observed.

[0091] All of the aqueous emulsions obtained in Examples 1 to 5 showed excellent stability with no phase separation after 3 months at 45° C. On the other hand, in Comparative Examples 1, 2, 4, 5, 7, and 8, separation of the oil phase and the aqueous phase was observed.

[0092] Furthermore, the glass bottles containing the emulsions were stored at a constant temperature of 4° C. for 3 months, and the presence or absence of crystals was observed under an optical microscope (LEICA DM 2700M; manufactured by Leica Microsystems KK; 200x magnification) at 25° C. No crystallization was observed in any of the aqueous emulsions obtained in Examples 1 to 5 and Comparative Examples 1 and 2, but crystallization was observed in the aqueous emulsions obtained in Comparative Examples 3 to 6 after 3 days, in the aqueous emulsion obtained in Comparative Example 7 after 2 weeks, and in the aqueous emulsion obtained in Comparative Example 8 after 4 weeks.

[0093] From the above, the aqueous emulsions of the present invention (Examples 1 to 5) show excellent stability without phase separation after storage at 45° C. for 3 months, and show excellent stability without crystallization after storage at 4° C. for 3 months, whereas the comparative examples show phase separation and / or crystallization after storage at 4° C. The results that (1) the aqueous emulsions of the present invention containing terephthalylidene dicamphor sulfonic acid are stable without crystallization at 4° C. relate to the combination of (2) a phosphorus-free compound or a salt thereof having at least two hydroxyl groups and an alkyl group having 16 to 22 carbon atoms, and (3) a polysaccharide thickener containing glucose, glucuronic acid, and rhamnose as main chain constituent monosaccharides.

Claims

1. (1) terephthalidene dicamphorsulfonic acid, (2) A phosphorus-free compound or a salt thereof having at least two hydroxyl groups and an alkyl group having 16 to 22 carbon atoms. (3) Polysaccharide thickeners containing glucose, glucuronic acid and rhamnose as main chain constituent monosaccharides. A water-based emulsion comprising:

2. The aqueous emulsion according to claim 1, wherein the component (2) comprises an organic acid monoglyceride and / or a salt thereof, an alkyl glyceryl ether, or a mixture thereof.

3. 3. The aqueous emulsion according to claim 1 or 2, wherein the component (2) comprises glyceryl citrate stearate and / or a salt thereof.

4. The aqueous emulsion according to any one of claims 1 to 3, wherein the total content of the component (2) is 0.1 mass% to 10 mass%, preferably 0.2 mass% to 8.0 mass%, and more preferably 0.3 mass% to 5.0 mass%, based on the total amount of the aqueous emulsion.

5. The aqueous emulsion according to any one of claims 1 to 4, wherein the component (3) comprises a polysaccharide thickener further containing at least one monosaccharide selected from the group consisting of rhamnose, fucose, glucose, and mannose as a side chain constituent monosaccharide.

6. The aqueous emulsion according to claim 5, wherein the component (3) comprises at least one polysaccharide thickener selected from diutan gum, welan gum, and gellan gum.

7. The aqueous emulsion according to any one of claims 1 to 6, wherein the content of the component (3) is 0.01 mass% to 2.0 mass%, preferably 0.05 mass% to 1.5 mass%, and more preferably 0.05 mass% to 1.0 mass%, based on the total amount of the aqueous emulsion.

8. The aqueous emulsion according to any one of claims 1 to 7, further comprising an emulsifier other than component (2), selected from the group consisting of polyglycerol esters of fatty acids having 12 to 24 carbon atoms and having 2 to 12 glycerin units, glycerol esters of fatty acids having 12 to 24 carbon atoms, and combinations thereof.

9. The aqueous emulsion according to any one of claims 1 to 8, further comprising a thickener other than the component (3), the thickener being selected from the group consisting of a (meth)acrylic polymer, a cellulose-based thickener, and a combination thereof.

10. (1) Terephthalidene dicamphor sulfonic acid (2) Organic acid monoglyceride and / or its salt, and / or alkyl glyceryl ether, preferably glyceryl citrate stearate and / or its salt, and (3) At least one thickening polysaccharide selected from the group consisting of diutan gum, welan gum, gellan gum, and combinations thereof. The aqueous emulsion according to any one of claims 1 to 9.

11. The aqueous emulsion according to any one of claims 1 to 10, which is an oil-in-water cosmetic.

12. The aqueous emulsion according to any one of claims 1 to 11, which is a sunscreen.

13. A cosmetic method for the care of keratinous materials, comprising applying an aqueous emulsion according to any one of claims 1 to 11 to keratinous materials, in particular to the skin.

14. 13. The aqueous emulsion according to any one of claims 1 to 12, for use as a sunscreen, in particular for preventing sunburn.

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