Oil-in-water emulsion

Abstract

The present invention provides an oil-in-water emulsion comprising (a) a polyacryloyldimethyl taurate, (b) a polysaccharide thickener containing diutan gum, (c) a water-soluble ultraviolet absorber, (d) an oil and (e) a pigment.

Description

DESCRIPTIONTitle of InventionOIL-IN-WATER EMULSIONTechnical Field

[0001] The present invention relates to an oil-in-water emulsion comprising water-soluble ultraviolet absorber.Background Art

[0002] Ultraviolet rays include UV-A and UV-B, with the shorter wavelength UV-B (wavelength: 280 to 320 nm) being absorbed mainly in the surface of the skin and also being thought to produce sunburn. UV-A (wavelength: 320 to 400 nm), which has a longer wavelength than UV-B, on the other hand, reaches to the dermis of the skin and is thought to produce suntan. Sunscreen performance is generally evaluated by SPF (Sun Protection Factor) and PA (Protection grade of UVA). SPF represents the extent of preventive effect against acute sunburn caused mainly by UV-B and is expressed as SPF 10, SPF20, SPF30, SPF40, SPF50 or SPF50+ depending on the degree of prevention. PA represents the extent of protective effect against UV-A, and is expressed as PA+, PA++, PA+++ or PA++++, depending on the degree of prevention.

[0003] Commonly used types of sunscreens include ultraviolet absorbers such as ethylhexyl methoxycinnamate (OMC) and oxobenzone, and ultraviolet scattering agents such as nano-TiCh and nano-ZnO. In recent years there has been increased review of the cosmetic ingredients used in sunscreens from the viewpoint of environmental considerations, safety and sustainability. However, it hasnot been easy to formulate sunscreens without using common conventional ultraviolet absorbers and ultraviolet scattering agents or reducing the amounts thereof used, while still exhibiting a high SPF / PA value and a comfortable texture.

[0004] Other ultraviolet absorbers including strong electrolytes such as phenylbenzimidazole-sulfonic acid (PBSA) and terephthalylidene dicamphor sulfonic acid (TDSA), as water-soluble ultraviolet absorbers that readily dissolve in aqueous phase, are used as ultraviolet absorbers for achieving high SPF / PA values. Examples of these include sunscreens containing water-soluble ultraviolet absorbers such as phenylbenzimidazole-sulfonic acid and gellan gum as hydrophilic gelling agent (disclosed in W02016008117A, W02016008121A, for example).Technical Problem

[0005] For a high-quality sunscreen, the texture during use is also important in addition to the SPF / PA value. For example, it is especially desirable for a sunscreen to have a cushioning texture or creamy texture (creamy feel), which in most cases is achieved by increasing the viscosity of the product, but increasing the viscosity is difficult with addition of strong electrolyte-based ultraviolet absorbers. This is because strong electrolytes inhibit hydrogen bonding in the gel network, thus lowering the viscosity. It has therefore been considered difficult to obtain the desired texture with strong electrolyte-type water- soluble ultraviolet absorbers. And the lowering of the viscosity has also an impact of the stability of the pigments (pigment flocculation) and homogeneity of the composition.

[0006] So there is still a need to provide an oil-in-water emulsion which can maintain viscosity even when adding a water-soluble ultraviolet absorber as the main ultraviolet absorber and pigment, and that exhibits stability and homogeneity of pigments, with a high SPF value and a smooth, creamy texture.Solution to Problem and Summary of Invention

[0007] The present inventors have found that an oil-in-water emulsion with a high SPF value and a smooth, creamy texture while maintaining high viscosity can be obtained by adding ammonium polyacryloyldimethyl taurate and diutan gum to an oil-in-water emulsion containing a water-soluble ultraviolet absorber.

[0008] The invention therefore relates to an oil-in-water emulsion that comprises (a) a polyacryloyldimethyl taurate, (b) a polysaccharide thickener comprising diutan gum, (c) a water-soluble ultraviolet absorber, (d) an oil and (e) a pigment.

[0009] According to a specific embodiment, component (a) in the oil- in-water emulsion comprises ammonium polyacryloyldimethyl taurate.

[0010] According to another specific embodiment, component (b) in the oil-in-water emulsion further comprises gellan gum and / or welan gum.

[0011] According to another specific embodiment, component (c) in the oil-in-water emulsion comprises a water-soluble ultraviolet absorber containing a sulfonic acid group.

[0012] According to another specific embodiment, component (c) in the oil-in-water emulsion comprises at least one component selected from the group consisting of phenylbenzimidazole-sulfonic acid or itssalt, terephthalylidene dicamphor sulfonic acid or its salt, phenyl dibenzimidazole tetrasulfonic acid or its salt, and hydroxymethoxybenzophenone sulfonic acid or its salt, and mixtures thereof.

[0013] According to another specific embodiment, the oil-in-water emulsion further comprises an ultraviolet filter other than component (c).

[0014] According to another specific embodiment, component (e) in the oil-in-water emulsion comprises a hydrophilic pigment and / or a hydrophobic pigment.

[0015] According to another specific embodiment, the oil-in-water emulsion further comprises a thickener other than component (b).

[0016] According to another specific embodiment, the oil-in-water emulsion is a cosmetic composition, and particularly a sunscreen.

[0017] The present invention further provides a cosmetic method for caring for keratinic materials, comprising the application onto a keratinic material, in particular onto skin, of the oil-in-water emulsion of the invention. This cosmetic method is a non-therapeutic method, meaning that the keratinic materials in the context of the invention are healthy, that is to say not presenting disorder or condition which would relate to a pathological state (“unhealthy” subjects, suffering from a pathology).Advantageous Effects of Invention

[0018] According to the invention it is possible to provide an oil-in- water emulsion containing a water-soluble ultraviolet absorber, which exhibits a high SPF value and a comfortable texture.Detailed description of the invention

[0019] Preferred embodiments of the invention will now be described in detail. However, the present invention is not limited to the described embodiments.

[0020] The oil-in-water emulsion of the invention comprises (a) a polyacryloyldimethyl taurate, (b) a polysaccharide thickener containing diutan gum, (c) a water-soluble ultraviolet absorber, (d) an oil and (e) a pigment.

[0021] The oil-in-water emulsion of the invention has a high SPF value due to addition of the (c) water-soluble ultraviolet absorber, and can maintain a high viscosity due to addition of an association of thickeners containing (a) a polyacryloyldimethyl taurate and (b) a polysaccharide thickener containing diutan gum, whereby it exhibits a smooth, creamy texture.

[0022] <Component (a)> Polyacryloyldimethyl taurateThe oil-in-water emulsion of the invention comprises a polyacryloyldimethyl taurate as component (a). Component (a) in the oil-in-water emulsion of the invention functions as a thickener.

[0023] The polyacryloyldimethyl taurate is not particularly restricted so long as it is an acceptable salt for addition to cosmetics, and examples include sodium polyacryloyldimethyl taurate and ammonium polyacryloyldimethyl taurate. According to a specific embodiment, component (a) includes ammonium polyacryloyldimethyl taurate.

[0024] The polyacryloyldimethyl taurate used in component (a) in the oil-in-water emulsion of the invention may be of a single type, or a combination of two or more types. According to a specificembodiment, component (a) is ammonium polyacryloyldimethyl taurate.

[0025] According to another specific embodiment, the total content of the polyacryloyldimethyl taurate of component (a) in the oil-in-water emulsion with respect to the total amount of the oil-in-water emulsion is 0.05 mass% or greater, 0.1 mass% or greater, 0.2 mass% or greater, 0.3 mass% or greater, 0.5 mass% or greater, 0.6 mass% or greater, 0.7 mass% or greater or 1 mass% or greater, and 25.0 mass% or lower, 20.0 mass% or lower, 15.0 mass% or lower, 10 mass% or lower, 5.0 mass% or lower, 2.5 mass% or lower or 1.0 mass% or lower, for example. The total content of component (c) is preferably in the range of 0.05 mass% to 25.0 mass% and especially 0.5 mass% to 20.0 mass%, with respect to the total amount of the oil-in-water emulsion.

[0026] <Component (b)> Polysaccharide thickener containing diutan gumThe oil-in-water emulsion of the invention comprises a polysaccharide thickener containing diutan gum, as component (b). Component (b) in the oil-in-water emulsion of the invention functions as a thickener.

[0027] Diutan gum (INCI: Sphingomonas ferment extract) is a polysaccharide obtained by aerobic fermentation of a com syrup starting material using Alcaligenes microbes. Addition of diutan gum can not only maintain high viscosity for the oil-in-water emulsion, but can also inhibit aggregation of the pigment of component (e), when the component (c) water-soluble ultraviolet absorbent is added.

[0028] According to a specific embodiment, component (b) comprises an additional polysaccharide thickener other than diutan gum. Thepolysaccharide thickener comprises glucose, glucuronic acid and rhamnose as constituent monosaccharides of the main chain. The polysaccharide thickener has, for example, a main chain with a structural unit comprising glucose, glucuronic acid, glucose and rhamnose bonded linearily in that order. The polysaccharide thickener may also have a side chain as part of the polysaccharide structure, or it may lack a side chain. The side chain may have one or more selected from the group consisting of rhamnose, fucose, glucose and mannose as a constituent monosaccharides. The polysaccharide thickener may have a main chain with a structural unit comprising glucose, glucuronic acid, glucose and rhamnose bonded linearily in that order, with rhamnose as a side chain. The polysaccharide thickener may have a main chain with a structural unit comprising glucose, glucuronic acid, glucose and rhamnose bonded linearily, with fucose as a side chain. The polysaccharide thickener may be obtained from a microbe such as a bacterium. According to a specific embodiment, the polysaccharide thickener other than diutan gum is welan gum, gellan gum, or a mixture thereof, for example. According to another specific and preferred embodiment, the oil-in-water emulsion further includes diutan gum and gellan gum as component (b).

[0029] The content of diutan gum in the oil-in-water emulsion of the invention may be 0.05 mass% or greater, 0.06 mass% or greater, 0.07 mass% or greater, 0.08 mass% or greater, 0.09 mass% or greater, 0.10 mass% or greater, 0.12 mass% or greater or 0.15 mass% or greater, and 5.0 mass% or lower, 4.0 mass% or lower, 3.0 mass% or lower, 2.0 mass% or lower, 1.0 mass% or lower or 0.5 mass% or lower or 0.2mass% or lower, for example, with respect to the total amount of the oil-in-water emulsion. The diutan gum content is especially in the range of 0.05 mass% to 2.0 mass% and especially 0.05 mass% to 1.0 mass%, with respect to the total amount of the oil-in-water emulsion.

[0030] The oil-in-water emulsion according to a specific embodiment contains a polysaccharide thickener other than diutan gum. The total content of the polysaccharide thickeners in the oil-in-water emulsion may be 0.05 mass% or greater, 0.06 mass% or greater, 0.07 mass% or greater, 0.08 mass% or greater, 0.09 mass% or greater, 0.1 mass% or greater, 0.11 mass% or greater, 0.12 mass% or greater, or 0.15 mass% or greater, and 2.0 mass% or lower, 1.5 mass% or lower, 1.0 mass% or lower, 0.8 mass% or lower, 0.5 mass% or lower, 0.25 mass% or lower, 0.2 mass% or lower or 0.15 mass% or lower, with respect to the total amount of the oil-in-water emulsion. The total content of the polysaccharide thickeners is especially in the range of 0.05 mass% to 2.0 mass% and especially 0.1 mass% to 1.0 mass%, with respect to the total amount of the oil-in-water emulsion. In a further specific embodiment, the total content of the polysaccharide thickeners other than diutan gum may be 0.05 to 5 times, for example 0.1 to 3 times, 0.2 to 2 times, 0.3 to 1 times, relative to the content of diutan gum.

[0031] cComponent (c)> Water-soluble ultraviolet absorber The oil-in-water emulsion of the invention includes a water-soluble ultraviolet absorber as component (c). Component (c) functions as an ultraviolet absorber. Water-soluble ultraviolet absorbers are environmental friendly with relatively high safety and excellent sustainability. “Water-soluble” means soluble in water at aconcentration of at least 1 mass% relative to the total mass of water at room temperature (25 °C) and at atmospheric pressure (105Pa).

[0032] The oil-in-water emulsion according to a specific embodiment comprises a water-soluble ultraviolet absorber containing a sulfonic acid group, as component (c). A water-soluble ultraviolet absorber containing a sulfonic acid group, being a strong electrolyte and exhibiting strong acidity, tends to generally lower the viscosity of the oil-in-water emulsion, but the oil-in-water emulsion of the invention is able to maintain high viscosity and exhibit a desirable texture such as cushioning texture, creamy feel, smooth feel by addition of component (a) and component (b).

[0033] The water-soluble ultraviolet absorber containing a sulfonic acid group is not particularly restricted, and examples include one or more selected from the group consisting of phenylbenzimidazolesulfonic acid or its salts, terephthalylidene dicamphor sulfonic acid or its salts, sodium phenyl dibenzimidazole tetrasulfonic acid or its salts, and hydroxymethoxybenzophenone sulfonic acid or its salt, and mixtures thereof.

[0034] Phenylbenzimidazole-sulfonic acid (common name: Ensulizole, chemical name: 2-phenyl-5 -benzimidazolesulfonic acid, CAS27503-81-7) is a water-soluble aromatic compound, being an ultraviolet absorber that acts to absorb primarily UV-B rays. Phenylbenzimidazole-sulfonic acid produces virtually no primary irritation on the skin, and is safe for the human body. Examples of salts of phenylbenzimidazole-sulfonic acid include inorganic salts such as tromethamine salt, sodium salts, potassium salts, calcium salts andmagnesium salts, or organic salts such as methylamine salts and dimethylamine salts. According to a specific embodiment, the salt of phenylbenzimidazole sulfonic acid is a tromethamine salt of phenylbenzimidazole sulfonic acid.

[0035] Terephthalylidene dicamphor sulfonic acid (common name: Ecamsule) (bicyclo [2.2.1] heptane- 1 -methanesulfonic acid, 3,3'-(l,4- phenylenedimethylidyne)bis[7.7]-dimethyl-2-oxo, CAS92761-26-7) is a water-soluble benzylidene camphor derivative, being an organic compound that absorbs UV-A (maximum absorption wavelength: 345 nm). Terephthalylidene dicamphor sulfonic acid has almost no dermal penetration, causes virtually no primary irritation of skin and is safe for the human body. Terephthalylidene dicamphor sulfonic acid is marketed under the name Mexoryl (Registered trademark) SX (Chimex), for example. Examples of salts of terephthalylidene dicamphor sulfonic acid include inorganic salts such as tromethamine salt, sodium salts, potassium salts, calcium salts and magnesium salts, or organic salts such as methylamine salts and dimethylamine salts. According to a specific embodiment, the salt of phenylbenzimidazole sulfonic acid is a tromethamine salt of phenylbenzimidazole sulfonic acid.

[0036] Phenyl dibenzimidazole tetrasulfonic acid (2,2'-(l,4- phenylene)bis(lH-benzimidazol-4, 6-disulfonic acid), CAS 180898-37- 7) is a water-soluble aromatic compound, being an ultraviolet absorber that acts to absorb primarily UV-B rays. Phenyl dibenzimidazole tetrasulfonic acid produces virtually no primary irritation on the skin, and is safe for the human body. Examples of salts of phenyldibenzimidazole tetrasulfonic acid include inorganic salts such as sodium salts, potassium salts, calcium salts and magnesium salts, or organic salts such as methylamine salts and dimethylamine salts. According to a specific embodiment, the salt of phenyl dibenzimidazole tetrasulfonic acid is sodium phenyl dibenzimidazole tetrasulfonate.

[0037] Hydroxymethoxybenzophenone sulfonic acid (common name: oxybenzone-4 or oxybenzonesulfonic acid, chemical name: 2-hydroxy- 4-methoxy-benzophenone-5-sulfonic acid) is a water-soluble benzophenone derivative, being an ultraviolet absorber that absorbs UV-B (maximum absorption wavelength: 285 to 286 nm) and UV-A (maximum absorption wavelength: 320 to 325 nm).Hydroxymethoxybenzophenone sulfonic acid produces virtually no primary irritation on the skin, and is safe for the human body. Examples of salts of Hydroxymethoxybenzophenone sulfonic acid include inorganic salts such as tromethamine salt, sodium salts, potassium salts, calcium salts and magnesium salts, or organic salts such as methylamine salts and dimethylamine salts. According to a specific embodiment, the salt of hydroxymethoxybenzophenone sulfonic acid is tromethamine salt of hydroxymethoxybenzophenone sulfonic acid.

[0038] Component (c) in the oil-in-water emulsion of the embodiment may be of a single type, or a combination of two or more different types. The total content of component (c) may be 0.5 mass% or greater, 1 mass% or greater, 1.5 mass% or greater or 2 mass% or greater, or 25 mass% or lower, 22 mass% or lower, 20 mass% or lower, 18 mass% orlower, 15 mass% or lower, or 10 mass% or lower, for example, with respect to the total amount of the oil-in-water emulsion. More specifically, the total content of component (c) is in the range of 0.5 mass% to 25 mass%, and especially 1 mass% to 22 mass% or 2 to 20 mass%, with respect to the total amount of the oil-in-water emulsion.

[0039] cComponent (d)> OilThe oil-in-water emulsion of the invention comprises an oil as component (d). According to a specific embodiment, the oil of component (d) may be a liquid oil, solid oil, or paste oil, for example, and according to one embodiment it is a liquid oil, or solid oil. A liquid oil may be either a non-polar liquid oil or a polar liquid oil.

[0040] A liquid oil is a non-volatile oil component that is liquid at ordinary temperature (in the range of 15 to 25°C) and ordinary pressure (1 atmosphere). Liquid oils include non-volatile hydrocarbon oils, higher alcohols, ester oils, ether oils and vegetable oils, and mixtures thereof.

[0041] Examples of non-volatile hydrocarbon oils include squalane, liquid paraffin, vaseline, polybutene, polyisobutene, hydrogenated polyisobutene, hydrogenated polydecene, olefin oligomers, and mixtures thereof.

[0042] Higher alcohols are aliphatic monoalcohols of 6 or more carbon atoms, or dihydric alcohols, and preferably aliphatic monoalcohols of 12 to 28 carbon atoms, or dihydric alcohols. Examples of higher alcohols include octyl alcohol, dodecyl alcohol, oleyl alcohol, octyldodecanol, hexyldecanol, isostearyl alcohol, decyltetradecanol and batyl alcohol, as well as mixtures thereof.

[0043] Ester oils are carboxylic acid esters that are liquid in environments at ordinary temperature and pressure (for example, 25°C, 1 atmosphere) and do not gasify, and they are preferably carboxylic acid alkyl esters wherein the carboxylic acid or alcohol of the ester has 8 to 18 carbon atoms. Examples of ester oils include propylene glycol fatty acid esters such as propylene glycol dicaprylate and propylene glycol dicaprate; fatty acid alkyl esters such as isoamyl laurate, hexyl laurate, ethylhexyl palmitate, isopropyl myristate, 2-octyldodecyl myristate, cetyl 2-ethylhexanoate, isononyl isononanoate and isotridecyl isononanoate; carbonic acid esters such as dicaprylyl carbonate; tri or greater fatty acid esters of polyglycerol such as polyglyceryl-2 triisostearate, polyglyceryl-2 tetraisostearate and polyglyceryl- 10 decaisostearate; glycerin tri fatty acid esters (also known as triglyceride oils) such as glyceryl tri-2-ethylhexanoate, glyceryl tribehenate, glyceryl tri(caprylate / caprate) and triheptanoin; benzoic acid derivatives such as diisostearyl malate and alkyl (Cl 2- 15) benzoates; salicylic acid derivatives such as homosalates and ethylhexyl salicylate; alkyl esters such as coconut oil alkyl (caprylate / caprate) and coconut oil alkyl caprylate; cinnamic acid derivatives such as octyl methoxycinnamate, isopropyl methoxycinnamate, isoamyl methoxycinnamate, cinnoxate, DEA methoxycinnamate, diisopropyl methylcinnamate, glyceryl- ethylhexanoate-dimethoxycinnamate and di-(2-ethylhexyl)-4'- methoxybenzalmalonate; and P,P-diphenyl acrylate derivatives such as octocrylene, as well as mixtures thereof.

[0044] Dicaprylyl ether is an example of an ether oil.

[0045] Examples of vegetable oils include meadowfoam seed oil, olive fruit oil, jojoba seed oil, camellia oil, coconut oil, macadamia nut oil, rosehip oil, avocado oil, sunflower seed oil, rice bran oil, castor oil and almond oil, as well as mixtures thereof.

[0046] Component (d) in the oil-in-water emulsion of the invention may be of a single type, or a combination of multiple different types. According to a specific embodiment, the total content of component (d) with respect to the total amount of the oil-in-water emulsion is 1 mass% or greater, 2 mass% or greater, 3 mass% or greater, 4 mass% or greater, 5 mass% or greater, 6 mass% or greater or 7 mass% or greater, and 60 mass% or lower, 50 mass% or lower, 45 mass% or lower, 40 mass% or lower, 35 mass% or lower, 30 mass% or lower, 15 mass% or lower or 10 mass% or lower, for example. The total content of component (d) is preferably in the range of 1 mass% to 45 mass% and especially 2 mass% to 30 mass%, with respect to the total amount of the oil-in-water emulsion.

[0047] <Component (e)> PigmentThe oil-in-water emulsion of the invention comprises a pigment as component (e). According to a specific embodiment, the pigment of component (e) is a hydrophilic pigment and / or a hydrophobic pigment, for example. According to another specific embodiment, the pigment of component (e) may be an organic synthetic dye, inorganic pigment, natural pigment, pearlescent pigment or polymer powder, or, hydrophilic or hydrophobic surface treatment products thereof, for example.

[0048] Organic synthetic dyes include dyes, lakes and organic pigments. Dyes include water-soluble dyes that dissolve in water, and oil-soluble dyes that dissolve in oils or alcohols. Lakes are non-water- soluble powders formed by chemical treatment of water-soluble dyes. Organic pigments are colored powders that are insoluble in water, oil or alcohol, and they include blue / green phthalocyanine pigments, blue indigo-based pigments, and red azo-based pigments.

[0049] Inorganic pigments are also referred to as "mineral pigments", and can be classified into color pigments, and white pigments and extender pigments. Color pigments include red iron oxide, yellow iron oxide, black iron oxide, ultramarine blue, Prussian blue, and chromium oxide. White pigments include titanium dioxide and zinc oxide.Extender pigments include barium oxide, aluminum hydroxide, aluminum oxide and silicon dioxide.

[0050] Natural pigments are pigments obtained by functions of animals, plants or microbes, and are largely classified into carotenoid, flavonoid and anthraquinone pigments. Carotenoid pigments are orange to yellow pigments found in ginseng, tomato, such as P-carotene. Flavonoid pigments are pigments found in flowers, perilla, turnip and grape skin, and include carthamin extracted from safflower.Anthraquinone-based pigments are found in madder, purple root and sea urchin, and include cochineal pigment, as an extract obtained by drying the male cactus parasite cochineal insect.

[0051] Pearlescent pigments include artificially produced titanium dioxide-coated mica pigments, as well as natural pearl powder.

[0052] The oil-in-water emulsion of the invention may also comprise fillers, in particular selected in the group consisting of mineral fillers, organic fillers, and mixtures thereof. As mineral fillers, mention may be made of mica, talc, kaolin, calcium carbonate, magnesium carbonate, and mixtures thereof. As organic fillers, mention may be made of polymer powders including powders of polyethylene, poly (methyl methacrylate) and nylon. The fillers used in the present invention may be surface treated so as to have hydrophilicity or hydrophobicity.

[0053] In a specific embodiment, hydrophilic pigments include water- soluble dyes; natural pigments such as carotenoid pigments, flavonoid pigments, anthraquinone pigments; hydrophilic organic pigments and the like. Examples of the hydrophilic pigment include an inorganic pigment, and a pearl pigment, which are surface-treated so as to have hydrophilicity. The hydrophilic surface treatment may be a treatment using a hydrate of alumina, silica, zirconia or the like. "Hydrophilic" means soluble or possible to be uniformly dispersed in water at a concentration of at least 1% by mass relative to the total mass of water at room temperature (25 °C) and atmospheric pressure (105Pa).

[0054] In a specific embodiment, hydrophobic pigments include hydrophobic organic pigments, inorganic pigments, pearl pigments, and the like. Examples of the hydrophobic pigment include an inorganic pigment, and a pearl pigment, which are surface-treated so as to have hydrophobicity. The hydrophobic surface treatment may be a treatment using metal soaps, N-acylated amino acids or salts thereof; lecithin and derivatives thereof; isopropyl titanium triisostearyl; diisostearyl sebacate; natural vegetable or animal waxes, polar synthetic waxes;fatty esters; phospholipids, and mixtures thereoft. "Hydrophobic" means that at room temperature (25 °C) and atmospheric pressure (105Pa), the soluble concentration or possible to be uniformly dispersed concentration relative to the total mass of water is less than 1% by mass, and is also referred to as "lipophilic".

[0055] The oil-in-water emulsion according to a specific embodiment includes a hydrophobic pigment, especially an inorganic pigment as component (e), and further especially hydrophobic iron oxide, hydrophobic titanium dioxide, hydrophobic aluminum hydroxide, hydrophobic aluminum oxide or hydrophobic silicon dioxide, or a combination of the same.

[0056] Component (e) in the oil-in-water emulsion of the embodiment may be of a single type, or a combination of multiple different types. According to a specific embodiment, the total content of component (e) with respect to the total amount of the oil-in-water emulsion is 0.1 mass% or greater, 0.2 mass% or greater, 0.3 mass% or greater, 0.4 mass% or greater, 0.55 mass% or greater, 0.6 mass% or greater or 1 mass% or greater, and 15 mass% or lower, 14 mass% or lower, 13 mass% or lower, 12 mass% or lower, 11 mass% or lower, 10 mass% or lower, 9 mass% or lower or 8 mass% or lower, for example. The total content of component (e) is preferably in the range of 0.1 mass% to 15 mass% and especially 0.5 mass% to 10 mass%, with respect to the total amount of the oil-in-water emulsion.

[0057] According to a specific embodiment, the total content of the hydrophobic pigment with respect to the total amount of the oil-in- water emulsion is 0.05 mass% or greater, 0.1 mass% or greater, 0.2mass% or greater, 0.3 mass% or greater, 0.5 mass% or greater, 0.6 mass% or greater or 0.7 mass% or greater, and 5 mass% or lower, 4 mass% or lower, 3 mass% or lower, 2 mass% or lower, 1 mass% or lower, 0.9 mass% or lower, or 0.8 mass% or lower, for example. The total content of hydrophobic pigment is preferably in the range of 0.05 mass% to 5 mass% and especially 0.05 mass% to 2 mass%.

[0058] <Other ultraviolet filters>According to a specific embodiment, the oil-in-water emulsion further includes an ultraviolet filter other than component (c). UV filters include organic UV filter (organic UV absorber) and / or inorganic UV filter (UV scattering agent). Organic UV absorbers include lipophilic organic UV absorbers and hydrophilic organic UV absorbers, each including UV-A absorbers, UV-B absorbers, and UV-A and UV-B absorbers.

[0059] The term "lipophilic organic UV filter" means an organic UV filter which is soluble in oils at a concentration of at least 1 mass% relative to the total mass of the oil at room temperature (25°C) and atmosphere pressure (105Pa).

[0060] Lipophilic organic UV-A absorbers include aminobenzophenone compounds, dibenzoylmethane compounds, anthranilic acid compounds and 4,4-diaryl butadiene compounds, and mixtures thereof. Aminobenzophenone compounds include diethylamino hydroxybenzoyl hexyl benzoate (DHHB, Product name: Uvinul A+ by BASF). Dibenzoylmethane compounds include 4- isopropyldibenzoylmethane (Product Name: Eusolex 8020 by Merck), l-(4-methoxy-l-benzofuran-5-yl)-3-phenylpropane-l, 3-dione (ProductName: Pongamol by Quest), l-(4-( / er / -butyl)phenyl)-3-(2- hydroxyphenyl)propane-l, 3 -dione and butyl methoxydibenzoylmethane (Product Name: Parsol 1789 by DSM). Anthranilic acid compounds include menthyl anthranilate (Product name: NEO HELIPAN MA by Symrise). 4,4-Diarylbutadiene compounds include 1,1 -dicarboxy (2,2'-dimethylpropyl)-4,4- diphenylbutadiene, diphenyl butadiene malonate and malononitrile.

[0061] Lipophilic organic UV-B absorbers include cinnamate compounds, salicylic compounds, anilino triazine compounds, benzoic acid compounds, diphenylacrylate compounds, benzylidene camphor compounds, phenylbenzimidazole compounds, imidazoline compounds, benzalmalonate compounds and mecocyanine compounds, and mixtures thereof.

[0062] Cinnamate compounds include ethylhexyl methoxycinnamate (product name: PARSOL CX by DSM), isopropyl ethoxycinnamate, isoamyl methoxycinnamate (product name: NEO HELIOPAN E 1000 by Symrise), diisopropyl methylcinnamate, cinoxate, glyceryl ethylhexanoate dimethoxycinnamate, octyl cinnamate, isopropylethyl cinnamate, diisopropylethyl cinnamate, methyldiisopropyl cinnamate, propylmethoxy cinnamate, isopropylmethoxy cinnamate, isoamylmethoxy cinnamate, octylmethoxy cinnamate, cyclohexylmethoxy cinnamate, ethyl-a-cyano-P-phenyl cinnamate, 2- ethylhexyl-a-cyano-P-phenyl cinnamate, glyceryl mono-2- ethylhexanoyl-diparamethoxy cinnamate and 3,4,5-trimethoxy-3- methyl-4-cinnamate[methylbis(trimethylsiloxy)silyl]butyl.

[0063] Salicylic compounds include ethylhexyl salicylate (product name: NEO HELIOPAN OS by Symrise), homosalate (product name: Eusolex HMS by Rona / EM industries), amyl salicylate, menthyl salicylate, homomenthyl salicylate, octyl salicylate, phenyl salicylate, benzyl salicylate and - isopropanol phenyl salicylate.

[0064] Anilino triazine compounds include tris-anilino triazine compounds such as ethylhexyl triazone (product name: UVINUL T-150 by BASF), 2,4,6-tris(dineopentyl 4'-aminobenzalmalonate)-s-triazine and 2,4,6-tris(diisobutyl 4'-aminobenzalmalonate)-s-triazine, and bis- anilino triazine compounds such as diethylhexyl butamido triazone (product name: UVASORB HEB by SIGMA 2 V).

[0065] Benzoic acid compounds include yara-aminobenzoates (PABA) such as ethyl PABA ( ara-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.

[0066] Diphenylacrylate compounds include octocrylene (product name: UVINUL N539 by BASF) and etocrylene (product name: UVINUL N35 by BASF). Benzylidenecamphor compounds include 3- benzylidene camphor (product name: MEXORYL SD by CHIMEX), methylbenzylidene camphor (product name: EUSOLEX 6300 by MERCK) and polyacrylamidomethyl benzylidene camphor (product name: MEXORYL SW by CHIMEX).

[0067] Phenylbenzimidazole compounds include phenylbenzimidazole sulfonic acid (product name: Eusolex 232 byMerck). Imidazoline compounds include ethylhexyl dimethoxybenzylidene dioxoimidazoline propionate. Benzalmalonate compounds include polyorganosiloxanes containing a benzalmalonate moiety, such as Polysilicone-15 (product name: Parsol SLX by DSM) and di-neopentyl 4'-methoxybenzalmalonate, for example.

[0068] Lipophilic UV-A and UV-B absorbers include benzophenone compounds, such as benzophenone-1 (product name: UVINUL 400 by BASF), benzophenone-2 (product name: UVINUL 500 by BASF), benzophenone-3 (product name: UVINUL M40 by BASF), benzophenone-6 (product name: Helisorb 11 by Norquay), benzophenone- 8 (product name: Spectra-Sorb UV-24 by American Cyanamid), benzophenone- 10, benzophenone-11 and benzophenone- 12; benzotriazole compounds such as drometrizole trisiloxane (product name: Silatrizole by Rhodia Chimie) and bumetrizole (product name: TINOGUARTD AS by CIBA); bis-resorcinyl triazine compounds such as bis-ethylhexyloxyphenol methoxyphenyl triazine (product name: TINOSORB S by CIBA); and benzoxazole compounds such as 2,4- bis[5-(l-dimethylpropyl)benzoxazol-2-yl(4-phenyl)imino]-6-(2- ethylhexyl)imino-l, 3,5-triazine (product name: Uvasorb K2A by Sigma 3 V).

[0069] Organic UV absorbers may include hydrophilic organic UV absorbers. The term "hydrophilic organic UV filter" means an organic UV filter which is soluble in water with neutralizers as needed at a concentration of at least 1 mass% relative to the total mass of the water at room temperature (25°C) and atmosphere pressure (105Pa). A waterdispersion of a lipophilic organic UV absorber can be also regarded as a hydrophilic organic UV absorber.

[0070] Hydrophilic organic UV-A absorbers include bisbenzoxazolyl derivatives, such as disodium phenyl dibenzimidazole tetrasulfonate and salts thereof (Product Name: Neo Heliopan AP by Haarmann and Reimer). Hydrophilic organic UV-A absorbers include benzylidene camphor derivative, such as Terephthalylidene Dicamphor Sulfonic Acid and salts thereof (Product Name: Mexoryl SX by Chimex).

[0071] Hydrophilic organic UV-B absorbers include -aminobenzoic (PABA)derivatives, such as PABA, glyceryl PABA and PEG-25 PABA and salts thereof (product name: Uvinul P25 by BASF, for example), benzimidazole sulfonic acid compounds such as phenylbenzimidazole sulfonic acid and salts thereof (product name: Eusolex 232 by Merck, for example), ferulic acid and salts thereof, salicylic acids and salts thereof, DEA methoxycinnamate and salts thereof, benzylidene camphor sulfonic acid and salts thereof (product name: Mexoryl SL by Chimex, for example) and camphor benzalkonium methosulfate and salts thereof (product name: Mexoryl SO by Chimex, for example).

[0072] An example of a water dispersion of a lipophilic organic UV absorber is a water dispersion of a lipophilic UV-A and UV-B filter, including a water dispersion such as a water dispersion of an alkylene bis-benzotriazolylphenol compound such as methylene bis- benzotriazolyl tetramethylbutylphenol (product name: TINOSORB M by BASF).

[0073] Hydrophilic organic UV-A and UV-B absorbers include benzophenone-4 and salts thereof (product name: Uvinul MS40 byBASF, for example), benzophenone- 5 and salts thereof, and benzophenone-9 and salts thereof.

[0074] The UV filter may comprise an inorganic UV filter (UV scattering agent). The UV scattering agent may be in the form of fine particles such that the mean primary particle diameter ranges from 1 nm to 50 pm, preferably 5 nm to 500 nm and more preferably 10 nm to 200 nm. The mean primary particle size is based on the arithmetic mean diameter.

[0075] The UV scattering agent is preferably a hydrophilic-treated or untreated metal oxide. Such metal oxides include titanium oxide and zinc oxide.

[0076] According to a specific embodiment, the total content of the ultraviolet filters other than component (c) with respect to the total amount of the oil-in-water emulsion may be 2 mass% to 50 mass%, 2 mass% to 50 mass%, 10 mass% to 25 mass%, or 10 mass% to 20 mass%.

[0077] <Other thickeners>The oil-in-water emulsion according to a specific embodiment further includes a thickener other than component (b). Examples of thickeners other than component (b) include (meth)acrylic (co)polymers, cellulosic thickeners, and polysaccharide thickeners such as glucomannan, xanthan gum or dehydroxanthan gum. Thickeners other than component (b) are preferably selected from the group consisting of (meth)acrylic (co)polymers, cellulosic thickeners and combinations thereof.

[0078] A (meth)acrylic-based copolymer may be a polymer obtained by polymerizing one or more monomers selected from the group consisting of (meth)acrylic acid and (meth)acrylic acid esters. There are no particular restrictions on the (meth)acrylic acid ester, which may be an alkyl (meth)acrylic acid ester, or the same wherein the alkyl group of the (meth)acrylic acid ester has been substituted with a substituent such as a hydroxyl group, and it is preferably an alkyl (meth)acrylic acid ester. Alkyl (meth)acrylic acid esters include alkyl (meth)acrylic acid esters with alkyl groups of 10 to 30 carbon atoms and alkyl (meth)acrylic acid esters with alkyl groups of 1 to 9 carbon atoms, and are preferably alkyl (meth)acrylic acid esters with alkyl groups of 10 to 30 carbon atoms. A (meth)acrylic-based copolymer may be a copolymer of at least one monomer selected from the group consisting of (meth)acrylic acid and alkyl (meth)acrylic acid esters with alkyl groups of 1 to 9 carbon atoms and at least one monomer selected from the group consisting of alkyl (meth)acrylic acid esters with alkyl groups of 10 to 30 carbon atoms.

[0079] A (meth)acrylic-based copolymer may also comprise a structural unit derived from (meth)acrylic acid. A structural unit derived from (meth)acrylic acid is a structural unit obtained by radical addition polymerization of (meth)acrylic acid. A structural unit obtained by radical addition polymerization may be any one with the same chemical structure as a structural unit obtained by radical addition polymerization and may optionally be a structural unit obtained by a method other than radical addition polymerization.

[0080] A (meth)acrylic-based copolymer may also be crosslinked. The crosslinking agent may be a compound having a plurality of ethylenic unsaturated groups in the molecule, such as a compound with a plurality of allyl ether groups in the molecule. Specifically, the crosslinking agent may be pentaerythrityl allyl ether, sucrose allyl ether, propylene allyl ether or sucrose allyl ether. A (meth)acrylic-based copolymer may be crosslinked with one or more crosslinking agents.

[0081] When a (meth)acrylic-based copolymer has carboxy groups, at least a portion of the carboxy groups may be neutralized. As used herein, "carboxy group" includes both the group COOH and neutralized COOH. When the carboxy group is neutralized, the counter cation of the carboxylic acid anion is not particularly restricted, and examples include alkali metal ions such as sodium ion and potassium ion, ammonium ion, organic ammonium ions, organic amines.

[0082] A (meth)acrylic-based copolymer may also include a carbomer. Examples of commercial products include Carbopol™ Ultrez 30 Polymer (EX-1142), Carbopol™ Ultrez 10, Carbopol™ ETD 2020, Carbopol™ Ultrez 20 Polymer and Pemulen TR-1, by Lubrizol Corp, Aristoflex™ AVC by Clariant, Simulgel™ NS MB by Seppic S.A.

[0083] According to a specific embodiment, the oil-in-water emulsion includes a cellulosic thickener. Examples of cellulosic thickeners include ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl methyl cellulose stearoxy ether, cellulose gum, carboxymethyl cellulose and mixtures thereof. According to a specific embodiment, the cellulosic thickener comprises an alkyl group of 10 to 30 carbon atoms from theviewpoint of further increasing the high temperature stability and further inhibiting stickiness of the oil-in-water emulsion. According to a specific preferred embodiment, the cellulosic thickener with an alkyl group of 10 to 30 carbon atoms is hydroxypropyl methyl cellulose stearoxy ether.

[0084] <Emulsifier>According to a specific embodiment, the oil-in-water emulsion may also comprise an emulsifier. Examples of emulsifiers include non-ionic emulsifiers (nonionic surfactants).

[0085] Examples of non-ionic emulsifiers include esters of polyglycerol and fatty acids (polyglycerol fatty acid esters) and esters of glycerols and fatty acids (glycerol fatty acid esters), with polyglycerol fatty acid esters being preferred.

[0086] According to a specific embodiment, a polyglycerol fatty acid ester is a polyglycerol ester of a fatty acid with 12 to 24, preferably 16 to 22, more preferably 18 to 22 and most preferably 18 or 22 carbon atoms. Examples for constituent fatty acids include palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, a-linolenic acid, y-linolenic acid, isostearic acid, arachidic acid, arachidonic acid and behenic acid. The fatty acid may be saturated or unsaturated, but it is preferably saturated. The number of glycerol units in the polyglycerol fatty acid ester (also referred to as the polymerization degree of the glycerol), may be 2 to 12, preferably 2 to 10 and more preferably 2 to 8, for example, with 2 or 6 being especially preferred.

[0087] According to a specific embodiment, the polyglycerol fatty acid ester is selected from the group consisting of polyglyceryl-2stearate, polyglyceryl-2 isostearate, polyglyceryl-2 oleate, polyglyceryl-6 stearate, polyglyceryl-6 behenate and mixtures thereof.

[0088] According to a specific embodiment, a glycerol fatty acid ester is a glycerol ester of a fatty acid with 12 to 24, preferably 16 to 22, more preferably 16 to 20 and most preferably 18 carbon atoms. Examples of fatty acids include palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, a-linolenic acid, y-linolenic acid, arachidic acid, arachidonic acid and behenic acid. The fatty acid may be saturated or unsaturated, but it is preferably saturated. According to a specific embodiment, the glycerol fatty acid ester is selected from the group consisting of glyceryl stearate, glyceryl oleate, glyceryl myristate, glyceryl coconut fatty acid esters, glyceryl undecylenate and mixtures thereof.

[0089] An emulsifier is preferably a solid at ordinary temperature (for example, 25°C). According to a particularly preferred embodiment, the emulsifier is preferably selected from the group consisting of poly glycerol esters of fatty acids of 12 to 24 carbon atoms and glycerol esters of fatty acids of 12 to 24 carbon atoms, having 2 to 12 glycerol units, and more preferably it is selected from among polyglycerol esters of fatty acids of 12 to 24 carbon atoms having 2 to 12 glycerol units, and mixtures thereof. In a particular embodiment, the emulsifier is polyglyceryl-6 stearate or polyglyceryl-6 behenate, for example. An example of a commercial product comprising a combination of polyglyceryl-6 stearate and polyglyceryl-6 behenate is TEGO CARE PBS 6 (Evonik Operations GmbH).

[0090] According to a specific embodiment, the emulsifier may be of a single type, or a combination of multiple different types. In a particular embodiment, the total content of the emulsifier with respect to the total amount of the oil-in-water emulsion is 0.1 mass% or greater, 0.2 mass% or greater, 0.5 mass% or greater, 0.7 mass% or greater, 1.0 mass% or greater or 1.2 mass% or greater, and 10 mass% or lower, 8 mass% or lower, 6 mass% or lower, 5 mass% or lower, 4 mass% or lower, 3 mass% or lower, 2.5 mass% or lower, 2.2 mass% or lower or 2 mass% or lower. The total content of emulsifiers with respect to the total amount of the oil-in-water emulsion is especially in the range of 0.5 mass% to 10 mass% and particularly 0.5 mass% to 5 mass% or preferably 1 mass% to 3 mass%.

[0091] <Humectant>According to a specific embodiment, the oil-in-water emulsion may also comprise a humectant. Examples of humectants include polyhydric alcohols of 3 to 5 carbon atoms. Examples of polyhydric alcohols include those with 2 or 3 alcoholic hydroxyl groups. Examples of polyhydric alcohols of 3 to 5 carbon atoms include glycerol, 1,3- butylene glycol, pentylene glycol and propanediol.

[0092] The content of a polyhydric alcohol of 3 to 5 carbon atoms with respect to the total amount of the oil-in-water emulsion may be 2 mass% or greater, 5 mass% or greater, 8 mass% or greater, 10 mass% or greater, 12 mass% or greater, 15 mass% or greater, 18 mass% or greater or 20 mass% or greater, and 30 mass% or lower, 28 mass% or lower, 25 mass% or lower, 23 mass% or lower, 20 mass% or lower, 18 mass% or lower or 15 mass% or lower, for example. In particular, thecontent of a polyhydric alcohol of 3 to 5 carbon atoms is in the range of 2 mass% to 30 mass% and especially 4 mass% to 30 mass%, with respect to the total amount of the oil-in-water emulsion.

[0093] <Other components>According to a specific embodiment, the oil-in-water emulsion may also contain additives commonly used in cosmetics, such as pH adjustors, perfumes, preservatives, active components, antioxidants, skin whiteners, coloring agents, and skin conditioning agents. According to a specific embodiment, the oil-in-water emulsion comprises an active component, and especially skin care active ingredients such as anti-aging agents.

[0094] The pH of the oil-in-water emulsion of the embodiment may be 5 to 9 or 5.5 to 8, for example, and is especially preferred to be 6 to 8.

[0095] According to a specific embodiment, the oil-in-water emulsion has a viscosity of 1,000 to 10,000 mPa-s, 1,500 to 9,000 mPa-s, 1,800 to 5,000 mPa-s, 2,000 to 4,000 mPa-s or 2,200 to 3,500 mPa-s, for example, as measured at 25°C. The viscosity can be measured based on the shear viscosity, using a rotational viscometer (for example, Rheolab QC by Anton Paar, spindle: ST-22-4V-40; rotational speed: 100 rpm). The oil-in-water emulsion of the embodiment can maintain a viscosity that provides a texture having cushioning texture and a creamy feel in spite of containing a water-soluble ultraviolet absorber as a main ultraviolet absorber.

[0096] According to the invention, the oil-in-water emulsion comprises water. The water content with respect to the total amount ofthe oil-in-water emulsion may be 30 mass% or greater, 35 mass% or greater, 45 mass% or greater, 47 mass% or greater, 49 mass% or greater, 51 mass% or greater, 53 mass% or greater, 55 mass% or greater, 58 mass% or greater, 60 mass% or greater or 61 mass% or greater, and 70 mass% or lower, 65 mass% or lower, 63 mass% or lower, 61 mass% or lower, 59 mass% or lower or 57 mass% or lower, for example. In particular, the total water content is in the range of 30 mass% to 70 mass% or 35 mass% to 65 mass%, especially 40 mass% to 60 mass% with respect to the total amount of the oil-in-water emulsion.

[0097] According to a specific embodiment, the oil-in-water emulsion of the invention can be produced, for example, by adding (a) a polyacryloyldimethyl taurate, (b) a polysaccharide thickener comprising diutan gum, (c) a water-soluble ultraviolet absorber, (d) an oil and (e) a pigment, and other components, water, in an appropriate order, and by stirring and mixing the mixture, while heating at 80 to 85°C, emulsifying the mixture, and then cooling to room temperature and mixing in other components.

[0098] According to another specific embodiment, the oil-in-water emulsion may be used as a cream ora fluid, for example. The oil-in- water emulsion may be an oil-in-water emulsion cosmetic, and especially a sunscreen.

[0099] The oil-in-water emulsion according to the invention has excellent long-term storage stability (for example, it does not undergo phase separation when stored for 3 months at 45 °C). A sunscreen according to a specific embodiment may have an ultraviolet shieldingpower of SPF30, SPF40, SPF50 or SPF50+, and most preferably SPF50+.Examples

[0100] [Preparation of oil-in-water emulsions]Oil-in-water emulsions of Examples 1 to 4 and Comparative Examples 1 to 14 were prepared with the ingredients and mixing ratios listed in Table 1 to Table 3. The "%" values in Tables 2 and 3 are all mass% values, based on the total mass of each oil-in-water emulsion. A 0.5 to 1.0 kg portion of the oil-in-water emulsion was prepared using a Rayneri agitator. The ingredients of Phase A were dissolved at 80°C. The ingredients of Phase D were dissolved at room temperature. The pigment ingredients of Phases E were dispersed using a TURREXA (registered trademark) homogenizer at room temperature at 12000 rpm for 30 minutes. The ingredients of Phase B were added to a tank and the tank was heated at 80°C and mixed at 100-500 rpm. After the bulk components in the tank became homogeneous, the ingredients of Phase C were added into the tank and mixed until the mixture swelled. The ingredients of Phase A were then added into the tank gradually and the mixture in the tank was emulsified with a Rayneri agitator for 5 min at 80°C, and then with a Turrax (registered trademark) homogenizer for 1 min at 10,000 rpm at room temperature. The mixture was air-cooled down to 30°C, and the ingredients of the remaining phases were added in order at below 40°C. The oil-in-water emulsions of Examples 1 to 4 and Comparative Examples 1 to 14 were obtained.

[0101] [Table 1]

[0102] [Table 2]

[0103] [Table 3]

[0104] The properties of each oil-in-water emulsion obtained were evaluated by the following methods. The viscosity was measured as the shear viscosity determined using a viscometer (Rheolab QC (Anton Paar), spindle: ST-22-4V-40; rotational speed: 100 rpm) at 25°C. Each oil-in-water emulsion was observed under an optical microscope (LEICA DM 2700M, Leica Microsystems Co., Ltd., 200x) after 24 hours. In vitro SPF values were measured using the SPF analyzer Labsphere UV-2000S. Stability was assessed by examining the state of the emulsion after storage at 4 °C for 1 month and after storage at 25 °C for 3 months. Creamy feel and smooth feel were assessed by the results of a panel of eight sensory evaluation experts.

[0105] All Examples and Comparative Examples contained the same amount of water-soluble ultraviolet absorbers, and the viscosity of these oil-in-water emulsions was measured. The viscosity of the oil-in- water emulsions of Examples 1 to 4 containing the diutan gum was 2200 mPa-s or more, which was higher than that of the oil-in-water emulsions of Comparative Examples 1, 3 to 8, and 10 to 12 not containing the diutan gum.

[0106] Comparative Example 1 containing gellan gum had a lower viscosity than Example 3 containing the same amount of diutan gum, but had a higher viscosity than other Comparative Examples containing neither diutan gum nor gellan gum. From this fact, gellan gum also had a constant viscosity maintaining effect and can be used in association with diutan gum. Comparative Example 2, which contained gellan gum in the same manner as Comparative Example 1 , further contained a hydrophobic pigment, and as a result, the pigment aggregated. On theother hand, in Example 3 similarly containing a hydrophobic pigment, no pigment aggregation was observed. From this fact, it was confirmed that diutan gum can further suppress aggregation of pigments.

[0107] The oil-in-water emulsion of Comparative Example 9, which contains polyacryloyldimethyl taurate but does not contain diutan gum, the oil-in-water emulsion of Comparative Example 13, which contains diutan gum but does not contain polyacryloyldimethyl taurate, and the oil-in-water emulsion of Comparative Example 13, which contains gellan gum but does not contain polyacryloyldimethyl taurate, were found to be inhomogeneous with clumps. These results suggest that the combination of diutan gum and polyacryloyldimethyl taurate is important for the maintenance of viscosity and the homogeneity of the emulsion.

[0108] The oil-in-water emulsions of Examples 1 and 3 showed in vitro SPF greater than 50. On the other hand, the in vitro SPF of the oil- in-water emulsion of Comparative Examples 3, 5 and 10 was less than 30.

[0109] Further, the oil-in-water emulsions of Examples 1 to 4 had excellent stability. In addition, the oil-in-water emulsions of Examples 1 , 2 and 4 had high creamy feel and smooth feel.

Claims

CLAIMS1. An oil-in-water emulsion, comprising(a) a polyacryloyldimethyl taurate;(b) a polysaccharide thickener comprising diutan gum;(c) a water-soluble ultraviolet absorber;(d) an oil; and(e) a pigment.

2. The oil-in-water emulsion according to claim 1, wherein component (a) comprises ammonium polyacryloyldimethyl taurate.

3. The oil-in-water emulsion according to claim 1 or claim 2, wherein component (b) further comprises gellan gum, and / or welan gum.

4. The oil-in-water emulsion according to any one of claims 1 to 3, wherein component (c) comprises a water-soluble ultraviolet absorber containing a sulfonic acid group.

5. The oil-in-water emulsion according to claim 4, wherein component (c) comprises at least one selected from the group consisting of phenylbenzimidazole-sulfonic acid or salt thereof, terephthalylidene dicamphor sulfonic acid or salt thereof, phenyldibenzimidazole tetrasulfonic acid or salt thereof, and hydroxymethoxybenzophenone sulfonic acid or its salt, and mixtures thereof.

6. The oil-in-water emulsion according to any one of claims 1 to 5, further comprising an ultraviolet filter other than component (c).

7. The oil-in-water emulsion according to any one of claims 1 to 6, wherein component (e) comprises a hydrophilic pigment and / or a hydrophobic pigment.

8. The oil-in-water emulsion according to any one of claims 1 to 7, further comprising a thickener other than component (b).

9. The oil-in-water emulsion according to any one of claims 1 to 8, which is a cosmetic composition.

10. A cosmetic method for caring for keratinic materials comprising the application onto keratinic materials, in particular onto skin, of the oil- in-water emulsion according to any one of claims 1 to 9.

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