oil-in-water emulsion

Abstract

An oil-in-water emulsion comprising (a) polyacryloyldimethyltaurate, (b) a polysaccharide thickener comprising diutan gum, (c) a water-soluble UV absorber, (d) an oil, and (e) a pigment.

Description

Technical Field

[0001] This invention relates to an oil-in-water emulsion containing a water-soluble ultraviolet absorber. Background Technology

[0002] Ultraviolet radiation includes UV-A and UV-B. Shorter wavelengths of UV-B (wavelength: 280 to 320 nm) are primarily absorbed by the skin surface and are believed to cause sunburn. On the other hand, longer wavelengths of UV-A (wavelength: 320 to 400 nm) can reach the dermis and are believed to cause tanning. Sun protection performance is typically evaluated using SPF (Sun Protection Factor) and PA (UVA Protection Level). SPF represents the level of protection against acute sunburn primarily caused by UV-B and is indicated by SPF10, SPF20, SPF30, SPF40, SPF50, or SPF50+. PA represents the level of protection against UV-A and is indicated by PA+, PA++, PA+++, or PA++++.

[0003] Commonly used sunscreen agents include UV absorbers, such as ethylhexyl methoxycinnamate (OMC) and oxybenzone, and UV scattering agents, such as nano-TiO2 and nano-ZnO. In recent years, due to environmental, safety, and sustainability considerations, scrutiny of cosmetic ingredients used in sunscreens has increased. However, formulating sunscreens that exhibit high SPF / PA values ​​and a comfortable texture without using common UV absorbers and UV scattering agents or by reducing their amounts has always been challenging.

[0004] Other UV absorbers, including strong electrolytes (such as phenylbenzimidazole sulfonic acid (PBSA) and terephthalic dicamphor sulfonic acid (TDSA)), are used as water-soluble UV absorbers that are readily soluble in the aqueous phase to achieve high SPF / PA values. Examples include sunscreens containing water-soluble UV absorbers (such as phenylbenzimidazole sulfonic acid) and gellan gum as a hydrophilic gelling agent (e.g., disclosed in WO2016008117A and WO2016008121A). Summary of the Invention

[0005] Technical issues For high-quality sunscreens, texture during application is just as important as SPF / PA values. For example, a cushion-like or creamy texture is particularly desirable in sunscreens, which is usually achieved by increasing the product's viscosity. However, with the addition of strong electrolyte-based UV absorbers, increasing viscosity becomes difficult. This is because strong electrolytes inhibit hydrogen bonding in the gel network, thus reducing viscosity. Therefore, it was previously considered difficult to achieve the desired texture using strong electrolyte-based water-soluble UV absorbers. Furthermore, reduced viscosity also affects pigment stability (pigment flocculation) and the homogeneity of the composition.

[0006] Therefore, there is still a need for an oil-in-water emulsion that maintains viscosity even when water-soluble UV absorbers are added as the main UV absorbers and pigments, and exhibits pigment stability and uniformity, while also having a high SPF value and a smooth, creamy texture.

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

[0008] Therefore, the present invention relates to an oil-in-water emulsion comprising (a) polyacrylamide dimethyl taurate, (b) a polysaccharide thickener comprising diotan gum, (c) a water-soluble ultraviolet absorber, (d) an oil, and (e) a pigment.

[0009] According to a specific implementation plan, component (a) in the oil-in-water emulsion contains ammonium polyacrylamide dimethyl taurate.

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

[0011] According to another specific implementation, component (c) of the oil-in-water emulsion contains a water-soluble UV 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 phenylbenzimidazole sulfonic acid or a salt thereof, terephthalimide dicamphor sulfonic acid or a salt thereof, phenyl dibenzimidazole tetrasulfonic acid or a salt thereof, hydroxymethoxybenzophenone sulfonic acid or a salt thereof, and mixtures thereof.

[0013] According to another specific implementation, the oil-in-water emulsion further includes an ultraviolet filter in addition to component (c).

[0014] According to another specific implementation, component (e) in the oil-in-water emulsion contains hydrophilic and / or hydrophobic pigments.

[0015] According to another specific implementation, the oil-in-water emulsion further includes a thickener in addition to component (b).

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

[0017] The present invention further provides a cosmetic method for caring for keratinized materials, comprising applying the water-in-oil emulsion of the present invention to the keratinized material, particularly to the skin. This cosmetic method is non-therapeutic, meaning that in the case of the present invention, the keratinized material is healthy, that is, it does not exhibit any disease or condition associated with a pathological state (“unhealthy” subject, suffering from a symptom).

[0018] Beneficial effects of the present invention According to the present invention, an oil-in-water emulsion containing a water-soluble ultraviolet absorber can be provided, which exhibits a high SPF value and a comfortable texture. Invention Details Preferred embodiments of the invention will now be described in detail. However, the invention is not limited to the described embodiments.

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

[0021] The oil-in-water emulsion of the present invention has a high SPF value due to the addition of (c) a water-soluble ultraviolet absorber, and maintains a high viscosity due to the addition of a thickener combination comprising (a) polyacrylamide dimethyl taurate and (b) a polysaccharide thickener comprising diothanide gum, thereby exhibiting a smooth, creamy texture.

[0022] <Component (a)> Polyacrylamide dimethyl taurate The oil-in-water emulsion of the present invention contains polyacrylamide dimethyl taurate as component (a). Component (a) in the oil-in-water emulsion of the present invention functions as a thickener.

[0023] There are no particular restrictions on polyacrylamide dimethyl taurate, as long as it is a salt permitted for addition to cosmetics; examples include sodium polyacrylamide dimethyl taurate and ammonium polyacrylamide dimethyl taurate. According to one specific embodiment, component (a) includes ammonium polyacrylamide dimethyl taurate.

[0024] The polyacrylamide dimethyl taurate used in component (a) of the oil-in-water emulsion of the present invention can be a single type or a combination of two or more types. According to a specific embodiment, component (a) is ammonium polyacrylamide dimethyl taurate.

[0025] According to another specific embodiment, for example, the total content of polyacrylamide dimethyl taurate of component (a) in the oil-in-water emulsion is 0.05% by mass or higher, 0.1% by mass or higher, 0.2% by mass or higher, 0.3% by mass or higher, 0.5% by mass or higher, 0.6% by mass or higher, 0.7% by mass or higher, or 1% by mass or higher, and 25.0% by mass or lower, 20.0% by mass or lower, 15.0% by mass or lower, 10% by mass or lower, 5.0% by mass or lower, 2.5% by mass or lower, or 1.0% by mass or lower, relative to the total amount of the oil-in-water emulsion. The total content of component (c) is preferably from 0.05% by mass to 25.0% by mass, particularly from 0.5% by mass to 20.0% by mass, relative to the total amount of the oil-in-water emulsion.

[0026] <Component (b)> Contains a polysaccharide thickener made from Dioton gum. The oil-in-water emulsion of the present invention comprises a polysaccharide thickener containing diotenoid gum as component (b). Component (b) in the oil-in-water emulsion of the present invention functions as a thickener.

[0027] Diyotan gum (INCI: Sphingomonas spp.) Sphingomonas Fermentation product extracts are obtained by using alkali-producing bacteria (Alcaligenes genus). Alcaligenes Polysaccharides obtained by aerobic fermentation of corn syrup starting material by microorganisms. Adding Dioton gum not only maintains the high viscosity of the oil-in-water emulsion, but also inhibits the aggregation of pigments in component (e) when component (c) (a water-soluble UV absorber) is added.

[0028] According to a specific embodiment, component (b) comprises a polysaccharide thickener other than dioentan gum. The polysaccharide thickener comprises glucose, glucuronic acid, and rhamnose as the main chain of constituent monosaccharides. The polysaccharide thickener, for example, has a main chain having structural units comprising glucose, glucuronic acid, glucose, and rhamnose linearly bonded in the following order. The polysaccharide thickener may also have side chains as part of the polysaccharide structure, or may not have side chains. The side chains may have one or more selected from rhamnose, fucose, glucose, and mannose as constituent monosaccharides. The polysaccharide thickener may have a main chain having structural units comprising glucose, glucuronic acid, glucose, and rhamnose linearly bonded in the following order, with rhamnose as a side chain. The polysaccharide thickener may have a main chain comprising structural units comprising glucose, glucuronic acid, glucose, and rhamnose linearly bonded, with fucose as a side chain. The polysaccharide thickener may be obtained from microorganisms, such as bacteria. According to one specific embodiment, the polysaccharide thickener other than diotenose gum is, for example, velan gum, gellan gum, or a mixture thereof. According to another specific and preferred embodiment, the oil-in-water emulsion further comprises diotenose gum and gellan gum as component (b).

[0029] In the oil-in-water emulsion of the present invention, the content of, for example, Dioten gum can be 0.05% by mass or higher, 0.06% by mass or higher, 0.07% by mass or higher, 0.08% by mass or higher, 0.09% by mass or higher, 0.10% by mass or higher, 0.12% by mass or higher, or 0.15% by mass or higher, and 5.0% by mass or lower, 4.0% by mass or lower, 3.0% by mass or lower, 2.0% by mass or lower, 1.0% by mass or lower, 0.5% by mass or lower, or 0.2% by mass or lower, relative to the total amount of the oil-in-water emulsion. The content of Dioten gum is particularly from 0.05% by mass to 2.0% by mass relative to the total amount of the oil-in-water emulsion, especially from 0.05% by mass to 1.0% by mass.

[0030] According to a specific embodiment, the oil-in-water emulsion contains a polysaccharide thickener other than diotenoid gum. The total content of the polysaccharide thickener in the oil-in-water emulsion can be 0.05% by mass or higher, 0.06% by mass or higher, 0.07% by mass or higher, 0.08% by mass or higher, 0.09% by mass or higher, 0.1% by mass or higher, 0.11% by mass or higher, 0.12% by mass or higher, or 0.15% by mass or higher, and 2.0% by mass or lower, 1.5% by mass or lower, 1.0% by mass or lower, 0.8% by mass or lower, 0.5% by mass or lower, 0.25% by mass or lower, 0.2% by mass or lower, or 0.15% by mass or lower, relative to the total amount of the oil-in-water emulsion. The total content of the polysaccharide thickener is particularly from 0.05% by mass to 2.0% by mass, and particularly from 0.1% by mass to 1.0% by mass, relative to the total amount of the oil-in-water emulsion. In a further specific implementation, the total content of polysaccharide thickeners other than diotenose can be 0.05 to 5 times, for example 0.1 to 3 times, 0.2 to 2 times, or 0.3 to 1 times, relative to the content of diotenose.

[0031] <Component (c)> Water-soluble UV absorber The oil-in-water emulsion of the present invention comprises a water-soluble ultraviolet absorber as component (c). Component (c) functions as an ultraviolet absorber. Water-soluble ultraviolet absorbers are environmentally friendly, possessing relatively high safety and excellent sustainability. "Water-soluble" refers to its ability to withstand temperatures up to 100°C and atmospheric pressures up to 100°C. 5 At a concentration of at least 1% by mass relative to the total mass of water (Pa), it is dissolved in water.

[0032] According to one specific embodiment, the oil-in-water emulsion comprises a water-soluble UV absorber containing sulfonic acid groups as component (c). Water-soluble UV absorbers containing sulfonic acid groups are strong electrolytes and exhibit strong acidity, typically tending to reduce the viscosity of oil-in-water emulsions. However, the oil-in-water emulsion of the present invention, by adding components (a) and (b), is able to maintain high viscosity and exhibit desired textures, such as cushion texture, creamy feel, or smooth feel.

[0033] There are no particular limitations on water-soluble ultraviolet absorbers containing sulfonic acid groups, and examples include one or more selected from the following: phenylbenzimidazole sulfonic acid or a salt thereof, terephthalimide dicamphor sulfonic acid or a salt thereof, sodium phenyldibenzimidazole tetrasulfonate or a salt thereof, hydroxymethoxybenzophenone sulfonic acid or a salt thereof, and mixtures thereof.

[0034] Phenylenic acid benzimidazole sulfonic acid (common name: Ensulizole, chemical name: 2-phenyl-5-benzimidazole sulfonic acid, CAS 27503-81-7) is a water-soluble aromatic compound and a UV absorber that primarily absorbs UV-B rays. Phenylenic acid benzimidazole sulfonic acid causes almost no Grade I skin irritation and is safe for human use. Examples of salts of phenylbenzimidazole sulfonic acid include inorganic salts (e.g., aminobutanetriol salts, sodium salts, potassium salts, calcium salts, and magnesium salts) or organic salts (e.g., methylamine salts and dimethylamine salts). According to one specific embodiment, the salt of phenylbenzimidazole sulfonic acid is an aminobutanetriol salt of phenylbenzimidazole sulfonic acid.

[0035] Terephthalimide dicamphor sulfonic acid (generic name: Ecamsule) (bicyclo[2.2.1]heptane-1-methanesulfonic acid, 3,3'-(1,4-phenylenedimethyl)bis[7.7]-dimethyl-2-oxo, CAS 92761-26-7) is a water-soluble benzyl camphor derivative and an organic compound that absorbs UV-A (maximum absorption wavelength: 345 nm). Terephthalimide dicamphor sulfonic acid has almost no percutaneous penetration, causes almost no first-degree skin irritation, and is safe for human use. Terephthalimide dicamphor sulfonic acid is marketed, for example, under the name Mexoryl (registered trademark) SX (Chimex). Examples of salts of terephthalimide dicamphor sulfonic acid include inorganic salts (e.g., glycerol, sodium, potassium, calcium, and magnesium salts) or organic salts (e.g., methylamine and dimethylamine salts). According to a specific implementation scheme, the salt of phenylbenzimidazole sulfonic acid is the aminobutanetriol salt of phenylbenzimidazole sulfonic acid.

[0036] Phenylenic dibenzimidazole tetrasulfonic acid (2,2'-(1,4-phenylene)bis(1H-benzimidazole-4,6-disulfonic acid), CAS 180898-37-7) is a water-soluble aromatic compound and a UV absorber that primarily absorbs UV-B rays. Phenylenic dibenzimidazole tetrasulfonic acid causes almost no Grade I skin irritation and is safe for human use. Examples of salts of phenyl dibenzimidazole tetrasulfonic acid include inorganic salts (e.g., sodium, potassium, calcium, and magnesium salts) or organic salts (e.g., methylamine and dimethylamine salts). According to one specific embodiment, the salt of phenyl dibenzimidazole tetrasulfonic acid is sodium phenyl dibenzimidazole tetrasulfonate.

[0037] Hydroxymethoxybenzophenone sulfonic acid (common name: oxybenzone-4 or oxybenzone sulfonic acid, chemical name: 2-hydroxy-4-methoxy-benzophenone-5-sulfonic acid) is a water-soluble benzophenone derivative and 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 causes almost no Grade I skin irritation and is safe for human use. Examples of salts of hydroxymethoxybenzophenone sulfonic acid include inorganic salts (e.g., aminobutanetriol salts, sodium salts, potassium salts, calcium salts, and magnesium salts) or organic salts (e.g., methylamine salts and dimethylamine salts). According to one specific embodiment, the salt of hydroxymethoxybenzophenone sulfonic acid is an aminobutanetriol salt of hydroxymethoxybenzophenone sulfonic acid.

[0038] Component (c) in the oil-in-water emulsion of the embodiment can be a single type or a combination of two or more different types. The total content of component (c) can be, for example, 0.5% by mass or higher, 1% by mass or higher, 1.5% by mass or higher, or 2% by mass or higher, or 25% by mass or lower, 22% by mass or lower, 20% by mass or lower, 18% by mass or lower, 15% by mass or lower, or 10% by mass or lower relative to the total amount of the oil-in-water emulsion. More specifically, the total content of component (c) is from 0.5% by mass to 25% by mass relative to the total amount of the oil-in-water emulsion, particularly from 1% by mass to 22% by mass or from 2% by mass to 20% by mass.

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

[0040] Liquid oils are non-volatile oil components that are liquid at room temperature (within the range of 15 to 25 °C) and at normal pressure (1 atmosphere). Liquid oils include non-volatile hydrocarbon oils, higher alcohols, ester oils, ether oils, and vegetable oils, as well as mixtures thereof.

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

[0042] Higher alcohols are aliphatic monohydric or dihydric alcohols with six or more carbon atoms, preferably aliphatic monohydric or dihydric alcohols with 12 to 28 carbon atoms. Examples of higher alcohols include octanol, dodecyl alcohol, oleyl alcohol, octyldodecyl alcohol, hexyldodecyl alcohol, isostearyl alcohol, decyltetradecyl alcohol, and squalene, and mixtures thereof.

[0043] Ester oils are carboxylic acid esters that are liquid and non-vaporizing at room temperature and pressure (e.g., 25°C, 1 atmosphere). They are preferably alkyl carboxylic acid 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 (e.g., propylene glycol dioctyl ester and propylene glycol didecanoate); alkyl fatty acid esters (e.g., isoamyl laurate, hexyl laurate, ethylhexyl palmitate, isopropyl myristate, 2-octyldodecyl myristate, 2-ethylhexanoate cetyl ester, isononyl isononanoate, and isotriadecyl isononanoate); carbonates (e.g., dioctyl carbonate); three or more fatty acid esters of polyglycerol (e.g., polyglycerol-2-triisostearate, polyglycerol-2-tetraisostearate, and polyglycerol-10-decadecyl istearate); triglyceride fatty acid esters (also known as triglyceride oils) (e.g., triglyceride-2-ethylhexanoate, triglyceride trihexaenoate, triglyceride tri(octyl / decanoate), and triheptyl ester). glyceryl esters); benzoic acid derivatives (e.g., diisostearyl malate and alkyl (C12-15) benzoate); salicylic acid derivatives (e.g., homosalate and ethylhexyl salicylate); alkyl esters (e.g., coconut oil alkyl (octanoate / decanoate) and coconut oil alkyl octanoate); cinnamic acid derivatives (e.g., octanoate methoxycinnamate, isopropyl methoxycinnamate, isoamyl methoxycinnamate, cinnoxalate, DEA methoxycinnamate, diisopropyl methyl cinnamate, glyceryl-ethylhexanoate-dimethoxycinnamate and di-(2-ethylhexyl)-4'-methoxybenzylidene malonate); and β,β-diphenylacrylate derivatives (e.g., octocrylene), and mixtures thereof.

[0044] Dioctyl 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, and mixtures thereof.

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

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

[0048] Organic synthetic dyes include dyes, lakes, and organic pigments. Dyes include water-soluble dyes that are soluble in water, and oil-soluble dyes that are soluble in oil or alcohol. Lakes are insoluble powders formed by chemically treating water-soluble dyes. Organic pigments are colored powders that are insoluble in water, oil, or alcohol; they include blue / green phthalocyanine pigments, blue indigo-based pigments, and red azo-based pigments.

[0049] Inorganic pigments, also known as "mineral pigments," can be classified into coloring pigments, as well as white pigments and extender pigments. Coloring pigments include red iron oxide, yellow iron oxide, black iron oxide, ultramarine, 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 through the function of animals, plants, or microorganisms, and are broadly classified into carotenoid pigments, flavonoid pigments, and anthraquinone pigments. Carotenoid pigments are orange to yellow pigments found in ginseng and tomatoes, such as beta-carotene. Flavonoid pigments are pigments found in flowers, perilla, turnips, and grape skins, including safflower glycoside extracted from safflower. Anthraquinone pigments are found in madder, gromwell root, and sea urchin, including cochineal red pigment (an extract obtained from the dried male cochineal insect, a cactus parasite).

[0051] Pearl pigments include artificially prepared mica pigments coated with titanium dioxide, as well as natural pearl powder.

[0052] The oil-in-water emulsion of the present invention may also contain fillers, particularly fillers selected from mineral fillers, organic fillers, and mixtures thereof. As mineral fillers, mica, talc, kaolin, calcium carbonate, magnesium carbonate, and mixtures thereof may be mentioned. As organic fillers, polymer powders, including polyethylene powder, poly(methyl methacrylate) powder, and nylon powder, may be mentioned. The fillers used in the present invention may be surface-treated to be hydrophilic or hydrophobic.

[0053] In one specific implementation, hydrophilic pigments include water-soluble dyes; natural pigments (e.g., carotenoid pigments, flavonoid pigments, anthraquinone pigments); and hydrophilic organic pigments. Examples of hydrophilic pigments include inorganic pigments and pearlescent pigments that have undergone surface treatment to acquire hydrophilicity. Hydrophilic surface treatments can be treatments using hydrates of alumina, silica, zirconium dioxide, etc. "Hydrophilic" refers to the ability to react at room temperature (25°C) and atmospheric pressure (10⁻⁶). 5 At a concentration of at least 1% by mass relative to the total mass of water, it is soluble in water or can be uniformly dispersed in water.

[0054] In one specific implementation, hydrophobic pigments include hydrophobic organic pigments, inorganic pigments, pearlescent pigments, etc. Examples of hydrophobic pigments include inorganic pigments and pearlescent pigments that have undergone surface treatment to become hydrophobic. Hydrophobic surface treatments can be treatments using metal soaps, N-acylated amino acids or their salts; lecithin and its derivatives; isopropyl triisostearate titanate; diisostearyl sebacate; natural plant or animal waxes, polar synthetic waxes; fatty acid esters; phospholipids and mixtures thereof. "Hydrophobic" refers to a state of hydrophobicity at room temperature (25°C) and atmospheric pressure (10⁻⁶). 5 At a concentration of less than 1% by mass relative to the total mass of water (Pa), the soluble concentration or the concentration that can be uniformly dispersed is also known as "lipophilic".

[0055] According to a specific implementation, the oil-in-water emulsion includes a hydrophobic pigment (especially an inorganic pigment) as component (e), particularly hydrophobic iron oxide, hydrophobic titanium dioxide, hydrophobic aluminum hydroxide, hydrophobic aluminum oxide or hydrophobic silicon dioxide, or combinations thereof.

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

[0057] According to a specific implementation scheme, for example, the total content of hydrophobic pigments relative to the total amount of the oil-in-water emulsion is 0.05% by mass or higher, 0.1% by mass or higher, 0.2% by mass or higher, 0.3% by mass or higher, 0.5% by mass or higher, 0.6% by mass or higher, or 0.7% by mass or higher, and 5% by mass or lower, 4% by mass or lower, 3% by mass or lower, 2% by mass or lower, 1% by mass or lower, 0.9% by mass or lower, or 0.8% by mass or lower. The total content of hydrophobic pigments is preferably from 0.05% by mass to 5% by mass, particularly from 0.05% by mass to 2% by mass.

[0058] <Other UV Filters> According to a specific implementation, the oil-in-water emulsion further comprises a UV filter in addition to component (c). The UV filter includes organic UV filters (organic UV absorbers) and / or inorganic UV filters (UV scatterers). Organic UV absorbers include lipophilic organic UV absorbers and hydrophilic organic UV absorbers, each comprising UV-A absorbers, UV-B absorbers, and both UV-A and UV-B absorbers.

[0059] The term "lipophilic organic UV filter" refers to a filter that operates at room temperature (25°C) and atmospheric pressure (10... 5 At a concentration of at least 1% by mass relative to the total mass of the oil, an organic UV filter is dissolved in the oil.

[0060] Lipophilic organic UV-A absorbers include aminobenzophenone compounds, benzoylmethane compounds, anthranilic acid compounds, and 4,4-diarylbutadiene compounds, and mixtures thereof. Aminobenzophenone compounds include hexyl diethylaminohydroxybenzoylbenzoate (DHHB, trade name: Uvinul A+ from BASF). Benzoylmethane compounds include 4-isopropylbenzoylmethane (trade name: Eusolex 8020 from Merck), 1-(4-methoxy-1-benzofuran-5-yl)-3-phenylpropane-1,3-dione (trade name: Pongamol from Quest), 1-(4-(tert-butyl)phenyl)-3-(2-hydroxyphenyl)propane-1,3-dione, and butylmethoxybenzoylmethane (trade name: Parsol 1789 from DSM). Anthranilic acid compounds include menthyl anthranilate (trade name: Symrise's NEO HELIPAN MA). 4,4-Diarylbutadiene compounds include 1,1-dicarboxy(2,2'-dimethylpropyl)-4,4-diphenylbutadiene, diphenylbutadiene malonate, and malononitrile.

[0061] Lipophilic organic UV-B absorbers include cinnamic acid esters, salicylic acid esters, aniline triazine esters, benzoic acid esters, diphenyl acrylate esters, benzyl camphor esters, phenylbenzimidazole esters, imidazoline esters, benzyl malonate esters, and gentiobiose anthocyanin esters, and mixtures thereof.

[0062] Cinnamic acid ester compounds include ethylhexyl methoxycinnamate (trade name: DSM's PARSOL CX), isopropyl ethoxycinnamate, and isoamyl methoxycinnamate (trade name: Symrise's NEO HELIOPAN E). 1000), diisopropyl methyl cinnamate, cinnoxalate, glyceryl ethylhexanoate, dimethoxycinnamate, octyl cinnamate, isopropyl ethyl cinnamate, diisopropyl ethyl cinnamate, methyl diisopropyl cinnamate, propyl methoxycinnamate, isopropyl methoxycinnamate, isopentyl methoxycinnamate, octyl methoxycinnamate, cyclohexyl methoxycinnamate, ethyl-α-cyano-β-phenyl cinnamate, 2-ethylhexyl-α-cyano-β-phenyl cinnamate, glyceryl mono-2-ethylhexanoyl-di-p-methoxycinnamate, and 3,4,5-trimethoxy-3-methyl-4-cinnamic acid [methylbis(trimethylsiloxy)silyl]butyl ester.

[0063] Salicylic acid compounds include ethylhexyl salicylate (trade name: NEO HELIOPAN OS of Symrise), humosalicylate (trade name: Eusolex HMS of Rona / EM Industries), pentyl salicylate, menthyl salicylate, menthol salicylate, octyl salicylate, phenyl salicylate, benzyl salicylate, and p-propylparaben salicylate.

[0064] Aniline triazine compounds include tri-aniline triazine compounds (e.g., ethylhexyl triazine ketone (trade name: BASF's UVINUL T-150), 2,4,6-tris(dineopentyl-4'-aminobenzylidene malonate)-s-triazine and 2,4,6-tris(diisobutyl-4'-aminobenzylidene malonate)-s-triazine), and bis-aniline triazine compounds (e.g., diethylhexylbutyrylaminotriazine ketone (trade name: SIGMA 2 V's UVASORB HEB)).

[0065] Benzoic acid compounds include para-aminobenzoic acid esters (PABA), such as ethyl PABA (para-aminobenzoic acid), dihydroxypropyl PABA, ethylhexyl dimethyl PABA, PABA monoglyceride, N,N-dipropoxy PABA, N,N-diethoxy PABA, N,N-dimethyl PABA, and N,N-dimethyl PABA butyl ester.

[0066] Diphenyl acrylate compounds include octocrylene (trade name: BASF's UVINUL N539) and etorylene (trade name: BASF's UVINUL N35). Benzylene camphor compounds include 3-benzylidene camphor (trade name: CHIMEX's MEXORYL SD), methylbenzylidene camphor (trade name: MERCK's EUSOLEX 6300), and polyacrylamide methylbenzylidene camphor (trade name: CHIMEX's MEXORYL SW).

[0067] Phenylbenzimidazole compounds include phenylbenzimidazole sulfonic acid (trade name: Eusolex 232 from Merck). Imidazolinone compounds include ethylhexyl dimethoxybenzyl dioxoimidazoline propionate. Benzyl malonate compounds include polyorganosiloxanes containing a benzyl malonate moiety, such as polysiloxane-15 (trade name: Parsol SLX from DSM) and dinepentyl 4'-methoxybenzyl malonate.

[0068] Lipophilic UV-A and UV-B absorbers include benzophenone compounds (e.g., benzophenone-1 (trade name: BASF's UVINUL 400), benzophenone-2 (trade name: BASF's UVINUL 500), benzophenone-3 (trade name: BASF's UVINUL M40), benzophenone-6 (trade name: Norquay's Helisorb 11), benzophenone-8 (trade name: American Cyanamid's Spectra-Sorb UV-24), benzophenone-10, benzophenone-11, and benzophenone-12); benzotriazole compounds (e.g., cresoltrazol trisiloxane (trade name: Rhodia Chimie's Silatrizole) and bumetriazole (trade name: CIBA's TINOGUARD AS)); and bis-resorcinol triazine compounds (e.g., bis-ethylhexyloxyphenol methoxyphenyl triazine (trade name: CIBA's TINOSORB)). S); and benzoxazole compounds (e.g., 2,4-bis[5-(1-dimethylpropyl)benzoxazole-2-yl(4-phenyl)imino]-6-(2-ethylhexyl)imino-1,3,5-triazine (trade name: Uvasorb K2A of Sigma 3V)).

[0069] Organic UV absorbers can include hydrophilic organic UV absorbers. The term "hydrophilic organic UV filter" refers to an absorber that operates at room temperature (25°C) and atmospheric pressure (10... 5 An organic UV filter, dissolved in water at a concentration of at least 1% by mass relative to the total mass of water, with the use of a neutralizing agent when necessary, at a concentration of 1% by mass. Aqueous dispersions of lipophilic organic UV absorbers can also be considered hydrophilic organic UV absorbers.

[0070] Hydrophilic organic UV-A absorbers include bisbenzoxazolyl derivatives (e.g., disodium phenyl dibenzimidazole tetrasulfonate and its salts (trade name: Neo Heliopan AP of Haarmann and Reimer)). Hydrophilic organic UV-A absorbers also include benzylidene camphor derivatives (e.g., terephthaloyl dicamphor sulfonic acid and its salts (trade name: MexorylSX of Chimex)).

[0071] Hydrophilic organic UV-B absorbers include para-aminobenzoic acid (PABA) derivatives (e.g., PABA, glycerol PABA, and PEG-25 PABA and their salts (e.g., BASF's Uvinul P25)), benzimidazole sulfonic acid compounds (e.g., phenylbenzimidazole sulfonic acid and its salts (e.g., Merck's Eusolex 232)), ferulic acid and its salts, salicylic acids and their salts, DEA methoxycinnamate and its salts, benzyl camphorsulfonic acid and its salts (e.g., Chimex's Mexoryl SL), and camphor benzalkonium methyl sulfate and its salts (e.g., Chimex's Mexoryl SO).

[0072] Examples of aqueous dispersions of lipophilic organic UV absorbers are aqueous dispersions of lipophilic UV-A and UV-B filters, including aqueous dispersions (e.g., aqueous dispersions of alkylene bis-benzotriazolylphenol compounds, such as an aqueous dispersion of methylene bis-benzotriazolyltetramethylbutylphenol (trade name: BASF's TINOSORB M)).

[0073] Hydrophilic organic UV-A and UV-B absorbers include benzophenone-4 and its salts (e.g., BASF's Uvinul MS40), benzophenone-5 and its salts, and benzophenone-9 and its salts.

[0074] UV filters may contain inorganic UV filters (UV scattering agents). The UV scattering agent may be in particulate form, such that the average primary particle size ranges from 1 nm to 50 μm, preferably from 5 nm to 500 nm, and more preferably from 10 nm to 200 nm. The average primary particle size is based on the arithmetic mean diameter.

[0075] UV scattering agents are preferably hydrophilically treated or untreated metal oxides. Such metal oxides include titanium oxide and zinc oxide.

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

[0077] <Other Thickeners> According to a specific embodiment, the oil-in-water emulsion further comprises a thickener other than component (b). Examples of thickeners other than component (b) include (meth)acrylic (co)polymers, cellulose thickeners, and polysaccharide thickeners (e.g., glucomannan, xanthan gum, or dehydroxanthan gum). The thickener other than component (b) is preferably selected from (meth)acrylic (co)polymers, cellulose thickeners, and combinations thereof.

[0078] The copolymer based on (meth)acrylic acid can be a polymer obtained by polymerizing one or more monomers selected from (meth)acrylic acid and (meth)acrylates. The (meth)acrylate is not particularly limited and can be an alkyl (meth)acrylate, or an alkyl (meth)acrylate wherein the alkyl group of the (meth)acrylate has been substituted with a substituent (e.g., hydroxyl), preferably an alkyl (meth)acrylate. Alkyl (meth)acrylates include alkyl (meth)acrylates having 10 to 30 carbon atoms and alkyl (meth)acrylates having 1 to 9 carbon atoms, preferably alkyl (meth)acrylates having 10 to 30 carbon atoms. The copolymer based on (meth)acrylic acid can be a copolymer of at least one monomer selected from (meth)acrylic acid and alkyl (meth)acrylates having 1 to 9 carbon atoms with at least one monomer selected from alkyl (meth)acrylates having 10 to 30 carbon atoms.

[0079] The copolymer based on (meth)acrylic acid may also include structural units derived from (meth)acrylic acid. The structural units derived from (meth)acrylic acid are obtained through radical addition polymerization of (meth)acrylic acid. The structural units obtained through radical addition polymerization can be any structural unit having the same chemical structure as those obtained through radical addition polymerization, and optionally can be structural units obtained by methods other than radical addition polymerization.

[0080] (Meth)acrylic acid-based copolymers can also be crosslinked. The crosslinking agent can be a compound having multiple vinyl unsaturated groups in its molecule, such as a compound having multiple allyl ether groups in its molecule. Specifically, the crosslinking agent can be pentaerythritol allyl ether, sucrose allyl ether, propylene allyl ether, or sucrose allyl ether. One or more crosslinking agents can be used to crosslink (meth)acrylic acid-based copolymers.

[0081] When a copolymer based on (meth)acrylic acid has a carboxyl group, at least a portion of the carboxyl group can be neutralized. As used herein, "carboxyl group" includes both the COOH group and the neutralized COOH. When the carboxyl group is neutralized, there are no particular limitations on the antication of the carboxylic acid anion; examples include alkali metal ions (e.g., sodium and potassium ions), ammonium ions, organic ammonium ions, and organic amines.

[0082] (Meth)acrylic acid-based copolymers may also include carbomer. Examples of commercially available products include Lubrizol Corp's Carbopol. TM Ultrez 30 Polymer (EX-1142), Carbopol TM Ultrez 10, Carbopol TM ETD2020, Carbopol TM Ultrez 20 Polymer and Pemulen TR-1, Clariant's Aristoflex TM AVC, Seppic SA's Simulgel TM NS MB.

[0083] According to one specific embodiment, the oil-in-water emulsion includes a cellulose-based thickener. Examples of cellulose-based thickeners include ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl methyl cellulose stearyl ether, cellulose gum, carboxymethyl cellulose, and mixtures thereof. According to one specific embodiment, for the purpose of further improving high-temperature stability and further suppressing the stickiness of the oil-in-water emulsion, the cellulose-based thickener contains an alkyl group having 10 to 30 carbon atoms. According to a specific preferred embodiment, the cellulose-based thickener having an alkyl group having 10 to 30 carbon atoms is hydroxypropyl methyl cellulose stearyl ether.

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

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

[0086] According to a specific embodiment, the polyglycerol fatty acid ester is a polyglycerol ester of a fatty acid having 12 to 24 carbon atoms, preferably 16 to 22 carbon atoms, more preferably 18 to 22 carbon atoms, and most preferably 18 or 22 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, arachidonic acid, arachidonic acid, and behenic acid. The fatty acid can be saturated or unsaturated, but is preferably saturated. The number of glycerol units in the polyglycerol fatty acid ester (also known as the degree of polymerization of glycerol) can be, for example, 2 to 12, preferably 2 to 10, more preferably 2 to 8, and particularly preferably 2 or 6.

[0087] According to a specific implementation scheme, the polyglycerol fatty acid ester is selected from polyglycerol-2 stearate, polyglycerol-2 isostearate, polyglycerol-2 oleate, polyglycerol-6 stearate, polyglycerol-6 behenate, and mixtures thereof.

[0088] According to one specific embodiment, the glycerol fatty acid ester is a glycerol 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 most 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, but is preferably saturated. According to one specific embodiment, the glycerol fatty acid ester is selected from glycerol stearate, glycerol oleate, glycerol myristate, glycerol cocoate, glycerol undecenoate, and mixtures thereof.

[0089] The emulsifier is preferably solid at room temperature (e.g., 25°C). According to a particularly preferred embodiment, the emulsifier is preferably selected from polyglycerol esters and glycerol esters of fatty acids having 12 to 24 carbon atoms and having 2 to 12 glycerol units, more preferably from polyglycerol esters and mixtures thereof. In a particular embodiment, the emulsifier is, for example, polyglycerol-6 stearate or polyglycerol-6 behenate. An example of a commercially available product containing a combination of polyglycerol-6 stearate and polyglycerol-6 behenate is TEGOCARE PBS 6 (Evonik Operations GmbH).

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

[0091] <Moisturizer> According to a specific implementation, the oil-in-water emulsion may also contain a humectant. Examples of humectants include polyols with 3 to 5 carbon atoms. Examples of polyols include polyols having 2 or 3 hydroxyl groups. Examples of polyols with 3 to 5 carbon atoms include glycerol, 1,3-butanediol, pentanediol, and propylene glycol.

[0092] The content of polyols with 3 to 5 carbon atoms can, for example, be 2% or more, 5% or more, 8% or more, 10% or more, 12% or more, 15% or more, 18% or more, or 20% or more, and 30% or less, 28% or less, 25% or less, 23% or less, 20% or less, 18% or less, or 15% or less, relative to the total amount of the oil-in-water emulsion. In particular, the content of polyols with 3 to 5 carbon atoms is 2% to 30% of the total amount of the oil-in-water emulsion, especially 4% to 30% of the total amount.

[0093] <Other Components> According to one specific implementation plan, oil-in-water emulsions may also contain additives commonly used in cosmetics, such as pH adjusters, fragrances, preservatives, active ingredients, antioxidants, skin whitening agents, colorants, and skin conditioning agents. According to one specific implementation plan, oil-in-water emulsions contain active ingredients, especially skin-care active ingredients, such as anti-aging agents.

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

[0095] According to a specific embodiment, the viscosity of the oil-in-water emulsion, as measured at 25°C, is, for example, 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. Viscosity can be measured based on shear viscosity using a rotational viscometer (e.g., Anton Paar Rheolab QC, rotor: ST-22-4V-40; rotation speed: 100 rpm). Despite containing a water-soluble UV absorber as the primary UV absorber, the oil-in-water emulsion of this embodiment maintains a viscosity that provides a cushion-like and creamy texture.

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

[0097] According to a specific embodiment, the oil-in-water emulsion of the present invention can be prepared, for example, by adding (a) polyacrylamide dimethyl taurate, (b) a polysaccharide thickener containing diothanide gum, (c) a water-soluble ultraviolet absorber, (d) oil and (e) pigments and other components, water, in an appropriate order, and stirring and mixing the mixture while heating at 80 to 85°C to emulsify the mixture, and then cooling it to room temperature and mixing in the other components.

[0098] According to another specific implementation, oil-in-water emulsions can be used, for example, as creams or fluids. Oil-in-water emulsions can be oil-in-water emulsion cosmetics, particularly sunscreens.

[0099] The oil-in-water emulsion according to the invention exhibits excellent long-term storage stability (e.g., no phase separation occurs when stored at 45°C for 3 months). The sunscreen agent according to a specific embodiment may have an ultraviolet shielding capacity of SPF30, SPF40, SPF50, or SPF50+, most preferably SPF50+. Detailed Implementation

[0100] Example [Preparation of oil-in-water emulsions] Oil-in-water emulsions of Examples 1 to 4 and Comparative Examples 1 to 14 were prepared according to the components and mixing ratios listed in Tables 1 to 3. The "%" values ​​in Tables 2 and 3 are mass percentages based on the total mass of each oil-in-water emulsion. Oil-in-water emulsions in portions of 0.5 to 1.0 kg were prepared using a Rayneri stirrer. The components of phase A were dissolved at 80°C. The components of phase D were dissolved at room temperature. The pigment components of phase E were dispersed for 30 minutes at 12,000 rpm at room temperature using a TURREXA (registered trademark) homogenizer. The components of phase B were added to a container, which was heated to 80°C and mixed at 100 to 500 rpm. After the bulk components in the container became homogenized, the components of phase C were added to the container and mixed until the mixture swelled. Then, the components of phase A were gradually added to the tank, and the mixture in the tank was emulsified for 5 minutes at 80°C using a Rayneri stirrer, followed by emulsification for 1 minute at room temperature and 10,000 rpm using a Turrax (registered trademark) homogenizer. The mixture was cooled to 30°C by air cooling, and the components of the remaining phases were added sequentially below 40°C. Oil-in-water emulsions of Examples 1 to 4 and Comparative Examples 1 to 14 were obtained. The performance of each oil-in-water emulsion was evaluated using the following methods. Viscosity was measured as shear viscosity at 25°C using a viscometer (Rheolab QC (Anton Paar), rotor: ST-22-4V-40; speed: 100 rpm). 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 a Labsphere UV-2000S SPF analyzer. Stability was assessed by examining the emulsions after 1 month of storage at 4°C and after 3 months of storage at 25°C. Creaminess and smoothness were evaluated using the results of a panel of eight sensory evaluation experts.

[0101] All examples and comparative examples contained the same amount of water-soluble ultraviolet absorber, and the viscosity of these oil-in-water emulsions was measured. The oil-in-water emulsions of Examples 1 to 4 containing Dioton gum had a viscosity of 2200 mPa·s or higher, which was higher than the viscosity of the oil-in-water emulsions of Comparative Examples 1, 3 to 8 and 10 to 12 without Dioton gum.

[0102] Comparative Example 1, containing gellan gum, had a lower viscosity than Example 3, which contained the same amount of diotenex, but higher viscosity than other comparative examples that contained neither diotenex nor gellan gum. This demonstrates that gellan gum also has a certain viscosity-retaining effect and can be used in conjunction with diotenex. Comparative Example 2, containing gellan gum in the same manner as Comparative Example 1, also contained a hydrophobic pigment, resulting in pigment aggregation. On the other hand, in Example 3, which also contained a hydrophobic pigment, no pigment aggregation was observed. This confirms that diotenex can further inhibit pigment aggregation.

[0103] The oil-in-water emulsions of Comparative Example 9 (containing polyacrylamide dimethyl taurate but not Dioten gum), Comparative Example 13 (containing Dioten gum but not polyacrylamide dimethyl taurate), and Comparative Example 13 (containing gellan gum but not polyacrylamide dimethyl taurate) were found to be heterogeneous and agglomerated. These results indicate that the combination of Dioten gum and polyacrylamide dimethyl taurate is important for maintaining viscosity and emulsion homogeneity.

[0104] The oil-in-water emulsions of Examples 1 and 3 exhibited an in vitro SPF greater than 50. On the other hand, the oil-in-water emulsions of Comparative Examples 3, 5, and 10 had an in vitro SPF less than 30.

[0105] Furthermore, the oil-in-water emulsions of Examples 1 to 4 exhibit excellent stability. Additionally, the oil-in-water emulsions of Examples 1, 2, and 4 possess a high degree of creaminess and smoothness.

Claims

1. An oil-in-water emulsion comprising: (a) Polyacrylamide dimethyl taurate; (b) A polysaccharide thickener containing diotan gum; (c) Water-soluble ultraviolet absorbers; (d) oil; and (e) Pigment.

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

3. The oil-in-water emulsion according to claim 1 or claim 2, wherein component (b) further comprises gellan gum and / or vegan 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 a salt thereof, terephthalimide dicamphor sulfonic acid or a salt thereof, phenyl dibenzimidazole tetrasulfonic acid or a salt thereof, hydroxymethoxybenzophenone sulfonic acid or a salt thereof, and mixtures thereof.

6. The oil-in-water emulsion according to any one of claims 1 to 5, further comprising an ultraviolet filter in addition to 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, wherein it is a cosmetic composition.

10. A cosmetic method for caring for keratinized materials, comprising applying an oil-in-water emulsion according to any one of claims 1 to 9 to the keratinized material, particularly to the skin.

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