Oil-in-water emulsion cosmetics

Abstract

To provide an oil-in-water emulsion cosmetic which has sunscreen effect, water resistance, is easy to spray, and has an excellent appearance when applied to the skin. The present invention relates to a composition comprising (A) a salt of a higher fatty acid component containing a liquid higher fatty acid, and (B) an oil-soluble ultraviolet absorber, and is essentially free of hydrophilic surfactants other than (A) the salt of the higher fatty acid component, has a pH of 8.0 to 9.5, has an oil droplet volume average particle diameter of 2 to 50 μm, and has a viscosity at 25°C of 100 [(mPa·s)×(g / cm 3 ) is the following oil-in-water emulsion cosmetic. This cosmetic is suitable as a spray-type cosmetic.

Description

[Technical Field]

[0001] The present invention relates to an oil-in-water emulsion cosmetic that not only has a sunscreen effect but also has an excellent aesthetic appearance when applied to the skin, and more particularly to an oil-in-water emulsion cosmetic that is suitable for use as a spray-type sunscreen cosmetic. [Background technology]

[0002] In recent years, attention has been drawn to the harmful effects of ultraviolet rays, and a variety of sunscreen cosmetics have been developed, including oil-in-water, water-in-oil, and solvent-based sunscreen cosmetics. These sunscreen cosmetics are used in a variety of forms, including liquids, emulsions, creams, and solid forms such as sticks, as well as spray-type forms that are used by spraying. Among these forms, spray-type sunscreen cosmetics have the advantages of being easily applied over a wide area without staining the hands and not requiring spreading after spraying on the skin, and are therefore well received in the market.

[0003] Among the various formulations of sunscreen cosmetics, oil-in-water sunscreen cosmetics, in which water is the continuous phase, provide a fresh feeling when applied to the skin and are excellent in terms of spreadability and glossiness, making them a formulation preferred by consumers. However, on the other hand, they are easily absorbed by sweat and water, resulting in poor durability of the cosmetic film, i.e., insufficient water resistance, and improvements in this area have been sought. Recently, it has been discovered that even with oil-in-water emulsion cosmetics, oil-in-water sunscreen cosmetics with high water resistance (water repellency) can be obtained by using a specific surfactant and controlling the pH of the system within a specific range (Patent Document 1).

[0004] The above-mentioned Patent Document 1 describes that an oil-in-water emulsion cosmetic, which contains 0.5 to 12 mass % of (A) a salt of a higher fatty acid component including a liquid higher fatty acid and 2 to 30 mass % of (B) an oil-soluble UV absorber, is substantially free of hydrophilic surfactants other than (A) the salt of the higher fatty acid component, and is an emulsion having a pH of 7.1 to 9.5, is a cosmetic that has a fresh feel when used, yet has high water resistance (water repellency) when applied to the skin, excellent durability of the UV protection effect and excellent storage stability, and can be easily removed with soap (Claim 1 and paragraph 0011).

[0005] As described above, the oil-in-water emulsion cosmetic described in Patent Document 1 is a good cosmetic having various advantages. However, when this cosmetic is prepared to have a low viscosity that allows it to be sprayed, and then filled into a sprayable container and sprayed, it has been found that even if it does not contain an ultraviolet scattering agent such as fine particle titanium dioxide, the coating film formed by spraying may appear white, which may not suit the preferences of consumers. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-221723 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0007] The present invention was completed against this background, and its object is to provide an oil-in-water emulsion cosmetic that maintains the advantages of the prior art, such as excellent sunscreen effect, water resistance (water repellency), storage stability, and ease of rinsing with soap, while providing an aesthetically pleasing appearance when filled into a spray container and applied to the skin. [Means for solving the problem]

[0008] As a result of extensive research aimed at solving these problems, the present inventors discovered that the particle size of the emulsion that forms an oil-in-water emulsion cosmetic significantly affects the occurrence of whiteness upon application, and that controlling the particle size within a specific range reduces the whiteness observed when the cosmetic is filled into a spray container and applied, leading to the completion of the present invention.

[0009] Thus, according to the present invention, there is provided a composition comprising (A) a salt of a higher fatty acid component containing a liquid higher fatty acid, and (B) an oil-soluble ultraviolet absorber, which is substantially free of hydrophilic surfactants other than (A) the salt of the higher fatty acid component, has a pH of 8.0 to 9.5, has an oil droplet volume average particle diameter of 2 to 50 μm, and has a viscosity at 25°C of 100 [(mPa·s)×(g / cm 3 )) is provided. [Effects of the Invention]

[0010] The oil-in-water emulsion cosmetic of the present invention has excellent sunscreen effect, water resistance (water repellency), storage stability, and washability with soap. Furthermore, when filled into a spray container and applied to the skin, the occurrence of whiteness is suppressed, and the desired cosmetic color can be maintained. DETAILED DESCRIPTION OF THE INVENTION

[0011] The oil-in-water emulsion cosmetic of the present invention contains (A) a salt of a higher fatty acid component containing a liquid higher fatty acid and (B) an oil-soluble ultraviolet absorber, and is substantially free of hydrophilic surfactants other than (A) the salt of the higher fatty acid component, has a pH of 8.0 to 9.5, a volume-average particle diameter of oil droplets of 2 to 50 μm, and a viscosity indicated at 25°C of 100 [(mPa·s)×(g / cm 3 )] is the following oil-in-water emulsion cosmetic.

[0012] In the present invention, the salt of a higher fatty acid component containing a liquid higher fatty acid (component A) is used as an emulsifier. The higher fatty acid component used to form the salt may consist solely of a liquid higher fatty acid or may be a mixture of a liquid higher fatty acid and a solid higher fatty acid. However, it is necessary to include a liquid higher fatty acid; if only a solid higher fatty acid is used, the spreadability and rinsability with soap decrease. The content of the liquid higher fatty acid is at least 30% by mass, preferably 50% by mass, and more preferably 90% by mass, of the total amount of higher fatty acids. The higher the proportion, the better the spreadability and rinsability with soap increase. Furthermore, if the higher fatty acid component is solely a liquid higher fatty acid, there is no need for a heating step in the preparation of the emulsion, which is economically advantageous and has the advantage of stable quality.

[0013] The liquid higher fatty acid used is usually one having 9 to 25 carbon atoms, and particularly preferably one having 11 to 22 carbon atoms, and specific examples thereof include oleic acid, linoleic acid, linolenic acid, arachidonic acid, hexyldecanoic acid, isostearic acid, etc. These may be used alone or in combination of two or more. Among these, isostearic acid, hexyldecanoic acid, and oleic acid are preferred from the viewpoints of emulsifier function, oxidation stability, and usability, and isostearic acid is more preferred.

[0014] In the present invention, isostearic acid refers to one type of branched stearic acid or a mixture of two or more types. For example, 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-octanoic acid can be produced by subjecting an isobutylene dimer to an oxo reaction to form a branched aldehyde having 9 carbon atoms, followed by aldol condensation of this aldehyde to form a branched unsaturated aldehyde having 18 carbon atoms, followed by hydrogenation and oxidation (hereinafter referred to as "aldol condensation type"). Aldol condensation type isostearic acid is commercially available, for example, from Nissan Chemical Industries, Ltd. 2-heptylundecanoic acid can be produced by dimerizing nonyl alcohol by the Guerbet reaction (also known as the Guerbet reaction) followed by oxidation. 2-heptylundecanoic acid is commercially available, for example, from Mitsubishi Chemical Corporation, and a similar compound with slightly different branching positions is commercially available from Nissan Chemical Industries, Ltd. Furthermore, Nissan Chemical Industries also sells a type in which the starting alcohol is not a linear alcohol but is branched at two positions (hereinafter collectively referred to as "Guerbet reaction type").

[0015] Furthermore, isostearic acid known as Emery type can also be used. Emery type isostearic acid refers to an isostearic acid of undefined structure, having 18 carbon atoms, a methyl group in the side chain, and obtained by hydrogenating an unsaturated fatty acid by-product during the synthesis of dimer acid from oleic acid (see, for example, J. Amer. Oil Chem. Soc. 51, 522 (1974)). Specific examples include those commercially available from Emery, Inc. in the United States, and Isostearic Acid EX manufactured by Kokyu Alcohol Kogyo Co., Ltd. The starting material for dimer acid, which is the starting material for Emery type isostearic acid, may include not only oleic acid but also linoleic acid, linolenic acid, etc. In the present invention, the Emery type is particularly preferably used.

[0016] In the present invention, the solid higher fatty acid that can be used in combination with the liquid higher fatty acid usually has 10 to 25 carbon atoms, and particularly preferably has 11 to 22 carbon atoms, and specific examples thereof include stearic acid, behenic acid, hydroxystearic acid, palmitic acid, myristic acid, and lauric acid.

[0017] On the other hand, the basic substance that constitutes component (A) above is not particularly limited as long as it is usable in the preparation of cosmetics, and specific examples include sodium hydroxide, potassium hydroxide, and triethanolamine.

[0018] The above-mentioned component (A) may be used as a higher fatty acid salt that has been neutralized with a base in advance, or the higher fatty acid component and basic substance may be added separately to the cosmetic production process, and the two components may be neutralized during the production process to form the higher fatty acid salt. When the two components are added separately, the higher fatty acid component and basic substance are usually added in equal amounts, but they do not necessarily have to be in equal amounts as long as the pH of the prepared emulsion is in the range of 8.0 to 9.5, and the higher fatty acid / base (molar ratio) can be appropriately selected in the range of 1 / 0.5 to 1 / 1.5.

[0019] In the oil-in-water emulsion cosmetic of the present invention, the blending amount of component (A) is typically 0.5 to 12% by mass, preferably 0.8 to 8% by mass, and more preferably 1 to 5% by mass. Furthermore, in the present invention, it is important that the composition is substantially free of hydrophilic surfactants other than component (A). Specific examples of hydrophilic surfactants other than component (A) include anionic surfactants other than salts of higher fatty acids, cationic surfactants, amphoteric surfactants, and nonionic surfactants with an HLB of 7 or higher. "Substantially free" means excluding these hydrophilic surfactants in amounts that would exert their active agent effects and impair the water resistance of the cosmetic film applied to the skin. Specifically, if they are present, their amount is preferably 0.2% by mass or less, and particularly 0.1% by mass or less, of the total cosmetic composition. Furthermore, even nonionic surfactants with an HLB of 7 or less are likely to reduce water resistance, so it is preferable to avoid their inclusion.

[0020] The pH of the oil-in-water emulsion cosmetic of the present invention is 8.0 to 9.5, preferably 8.0 to 8.5. In the case of the oil-in-water emulsion cosmetic of the present invention, in which the oil droplets have a large particle size and a low viscosity, the oil droplets are more likely to coalesce than in oil-in-water emulsion cosmetics with a small particle size and a high viscosity. If the pH is less than 8.0, the storage stability is insufficient, and the oil droplets tend to coalesce over time, resulting in separation of the oil and aqueous phases. If the pH exceeds 9.5, the pH of the skin surface upon application to the skin will be 7.0 or higher, and sufficient water resistance will not be achieved. The pH of a cosmetic is primarily determined by the molar ratio of higher fatty acid to base. If there is a component other than the essential components of the present invention that affects the pH, the pH of the cosmetic is adjusted to 8.0 to 9.5 by the amount of base or, if necessary, a pH buffer.

[0021] The oil-soluble ultraviolet absorber of component (B) used in the present invention is not particularly limited as long as it is one that is normally used in cosmetics and topical skin preparations, and examples thereof include the following. Cinnamic acid-based ultraviolet absorbers such as benzyl paramethoxycinnamate, 2-ethylhexyl paramethoxycinnamate, and glyceryl di-paramethoxycinnamate mono-2-ethylhexanoate; benzophenone-based ultraviolet absorbers such as hydroxymethoxybenzophenone, dihydroxymethoxybenzophenone, dihydroxybenzophenone, and tetrahydroxybenzophenone; Benzoate ester-based ultraviolet absorbers such as para-aminobenzoic acid, ethyl para-aminobenzoate, glyceryl para-aminobenzoate, amyl para-dimethylaminobenzoate, octyl para-dimethylaminobenzoate, ethyl 4-[N,N-di(2-hydroxypropyl)amino]benzoate, and hexyl diethylaminohydroxybenzoylbenzoate; salicylic acid-based ultraviolet absorbers such as ethylene glycol salicylate, phenyl salicylate, octyl salicylate, benzyl salicylate, para-tert-butylphenyl salicylate, and homomenthyl salicylate; Triazine-based ultraviolet absorbers such as ethylhexyltriazone (2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]1,3,5-triazine) and bisethylhexyloxyphenol methoxyphenyl triazine; Other UV absorbers such as 4-tert-butyl-4'-methoxydibenzoylmethane, menthyl anthranilate, 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-ethylhexyl dimethoxybenzylidene dioxoimidazolidinepropionate, octocrylene, dimethicodiethyl benzalmalonate, etc.

[0022] Among these, when UV absorbers such as 2-ethylhexyl paramethoxycinnamate, glyceryl di-paramethoxycinnamate mono-2-ethylhexanoate, octyl salicylate, homomenthyl salicylate, bisethylhexyloxyphenol methoxyphenyl triazine, dihydroxybenzophenone, octocrylene, 4-tert-butyl-4'-methoxydibenzoylmethane, and diethylaminohydroxybenzoylhexylbenzoate are selected, a particularly high UV protection effect can be obtained.

[0023] The oil-soluble UV absorbers can be used alone or in combination. The amount of the oil-soluble UV absorber (B) added is usually 2 to 30% by mass, preferably 5 to 25% by mass, and more preferably 8 to 22% by mass.

[0024] The oil-in-water emulsion cosmetic of the present invention may contain other ingredients that are typically incorporated into cosmetics, such as water-soluble ultraviolet absorbers, powders, oils, water-soluble polymers, film-forming agents, alcohols, clay minerals, resins, moisturizers, preservatives, antibacterial agents, fragrances, salts, antioxidants, pH adjusters, chelating agents, cooling agents, anti-inflammatory agents, skin-beautifying ingredients, vitamins, amino acids, nucleic acids, and inclusion compounds.

[0025] Specific examples of water-soluble ultraviolet absorbers that can be added include hydroxymethoxybenzophenone sulfonic acid, sodium hydroxymethoxybenzophenone sulfonate, sodium dihydroxymethoxybenzophenone disulfonate, and 2-phenylbenzimidazole-5-sulfonic acid.

[0026] The powders that can be blended are not particularly limited in terms of shape (e.g., plate-like, spindle-like, or needle-like), particle size, or particle structure (e.g., porous or non-porous), as long as they do not produce a white cast when filled into a spray container and applied to the skin. Specific examples of powders include silicone elastomer powders such as vinyl dimethicone / methicone silsesquioxane crosspolymer and vinyl methicone / vinyl diphenyl dimethicone / silsesquioxane crosspolymer. Blending such silicone elastomer powders can adjust the skin feel and application sensation. When blending silicone elastomer powders, the blending amount is preferably 0.1 to 10% by mass, and more preferably 0.5 to 5% by mass. The blending of white pigments such as titanium oxide or zinc oxide results in a white coating, while the blending of color pigments such as black iron oxide, red iron oxide, or yellow iron oxide results in the color of the color pigment appearing in the coating, so it is preferable not to blend them.

[0027] The oils that can be blended are not particularly limited as long as they are oils that are blended into ordinary cosmetics, and any oil can be used regardless of its origin (e.g., animal oil, vegetable oil, synthetic oil) or its properties (e.g., solid oil, semi-solid oil, liquid oil, volatile oil, etc.) Specific examples include oils such as hydrocarbons, oils and fats, waxes, hydrogenated oils, ester oils, higher alcohols, silicone oils, fluorine-based oils, and lanolin derivatives.

[0028] The oil-in-water sunscreen cosmetic of the present invention is an emulsion in which oil droplets having a volume average particle size of 2 to 50 μm are dispersed in an aqueous phase that forms the continuous phase. The volume average particle size of the oil droplets is an important requirement of the present invention; if the volume average particle size is less than 2 μm, the oil droplets are likely to become white when filled into a spray container and applied, while if the volume average particle size exceeds 50 μm, the oil droplets are likely to coalesce, resulting in reduced storage stability. The volume average particle size of the oil droplets is preferably 2 to 30 μm, and particularly preferably 3 to 15 μm.

[0029] The volume-average particle size can be measured using a laser diffraction / scattering particle size distribution analyzer (e.g., HORIBA LA-950). The measurement method in this case involves using a flow cell, setting the dispersion solvent to purified water, and the refractive index of the dispersoid to 1.543-0.000i, the refractive index of which is that of ethylhexyl paramethoxycinnamate, a typical UV absorber. An oil-in-water emulsion is added to the flow cell, and measurements are performed at a concentration that shows a transmittance of around 90%, to determine the volume-based average particle size.

[0030] The oil-in-water emulsion cosmetic of the present invention is prepared by dispersing the component (B) in water using the component (A) as a surfactant. The method for preparing the cosmetic is not particularly limited, and the following methods can be used, for example. Preparation method (1): Dispersion emulsification method In this method, an aqueous phase containing component (A) and an oil phase containing component (B) are prepared in advance, and then the oil phase containing component (B) is gradually added to the aqueous phase containing component (A) while stirring to form an oil-in-water emulsion. Preparation method (2): Soap emulsification method (sometimes called the interfacial reaction method) In this method, the higher fatty acid component and basic substance that constitute component (A) are blended separately, and the higher fatty acid component is blended together with component (B) into an oil phase, and the aqueous phase blended with the basic substance is gradually added to the oil phase under stirring to generate a fatty acid salt at the oil-water interface, thereby forming an oil-in-water emulsion. Preparation method (3): D phase emulsification method In this method, a mixture called phase D (surfactant phase) containing component (A), a polyhydric alcohol such as propylene glycol, dipropylene glycol, 1,3-butylene glycol, or glycerin, and water is first formed, and then an oil phase containing component (B) is gradually added under stirring to form a gel-like emulsion (O / D phase), which is then further diluted with water as needed to form an oil-in-water emulsion.

[0031] Another known method for preparing oil-in-water emulsions is the phase inversion temperature emulsification method, which utilizes the property that the balance between hydrophilicity and lipophilicity changes with temperature using a hydrophilic nonionic surfactant such as PEG-50 hydrogenated castor oil. However, this method has problems in that it is difficult to control the volume average particle size of the oil droplets to 2 to 50 μm, and the inclusion of a hydrophilic surfactant other than component (A) results in poor water resistance (water repellency).

[0032] In the above-mentioned preparation methods (1) and (2), the size of the oil droplets varies depending on the magnitude of the shear force during mixing (emulsification) of the oil phase and the aqueous phase. Therefore, the volume-average particle size of the oil droplets can be controlled by controlling the shear force. Furthermore, in preparation method (3), the volume-average particle size of the oil droplets can be controlled, for example, by adjusting the type and amount of polyhydric alcohol. Among these preparation methods, (2) the soap emulsification method is preferred because it facilitates particle size control and produces emulsions with excellent stability. In the above-mentioned preparation methods (1) and (2), the shear force during mixing of the oil phase and the aqueous phase varies depending on the peripheral speed of the stirring blade. The particle size of the oil droplets decreases as the shear force during mixing of the oil phase and the aqueous phase increases. Therefore, to achieve a volume-average particle size of 2 to 50 μm, it is preferable to conduct preliminary experiments to determine stirring conditions that result in an appropriate shear force.

[0033] The oil-in-water emulsion cosmetic of the present invention may be in any of the following forms: emulsion, liquid (dilute emulsion), or two-layer form separated into two layers: an emulsion phase and an aqueous phase. Among these, it is preferable to fill a low-viscosity liquid into a spray container and use it as a spray-type cosmetic. Examples of spray containers used in this case include trigger spray containers (direct pressure or accumulated pressure type), dispenser-type pump spray containers, and aerosol spray containers equipped with pressure-resistant containers. Among these, non-gas pump spray containers are preferred because they are easy to use and environmentally friendly. This cosmetic can be used not only as a sunscreen cosmetic but also as other cosmetics imparted with UV protection. Specific examples of other cosmetics include makeup cosmetics such as foundations and primers, skin care cosmetics such as emulsions, creams, and serums, and hair cosmetics. In the case of a spray-type cosmetic, it can also be used as a finishing cosmetic (also known as a topcoat cosmetic) that is sprayed onto skin after makeup has been applied.

[0034] When preparing a spray-type cosmetic product, the viscosity value measured at 25°C using a tuning fork vibration viscometer (hereinafter sometimes simply referred to as "viscosity value") is preferably 100 [(mPa·s) × (g / cm 3 )] or less, and 10[(mPa·s)×(g / cm 3 100 [(mPa·s)×(g / cm 3 ) is larger than the above range, it is not preferable because when sprayed as a dispenser-type or aerosol-type cosmetic, the mist will not be uniform, resulting in noticeable whiteness when applied.

[0035] The viscosity display value can be measured using a tuning fork vibration viscometer SV-10 (manufactured by A&D Corporation) under the following conditions: measurement temperature 25°C, frequency 30Hz, measurement time 30 seconds. The physical quantity obtained by this measurement is detected as the product of viscosity and density, so the viscosity display value is expressed in units of [(mPa·s) × (g / cm 3 )]. [Example]

[0036] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples in any way. The amount of each component is expressed in "% by mass" unless otherwise specified. The oil-in-water emulsion cosmetics in the following examples and comparative examples were evaluated as follows.

[0037] (pH) The pH was measured at a liquid temperature of 25°C using a pH meter (manufacturer: Toa DKK, model number: WM-22EP).

[0038] (viscosity display value) Measurements were carried out under the following conditions using an A&D tuning fork vibration viscometer (SV-10). Measurement temperature: 25℃ Frequency: 30Hz Measurement time: 30 seconds

[0039] (Volume average particle size of oil droplets) The size of the oil droplets (volume average particle diameter) was measured using a laser diffraction / scattering particle size distribution analyzer (manufacturer: Horiba, Model No.: LA-950) under the following conditions: Dispersion solvent: Purified water Measurement cell: Flow cell Refractive index: 1.543-0.000i Measurements were carried out at a concentration where the transmittance was around 90%, and the average particle diameter was calculated on a volume basis.

[0040] (Whiteness when applied) The sample was placed in a 30cc dispenser-type pump spray container (product name: Z-155-C114, manufactured by Gracel Co., Ltd.) and sprayed onto the forearm of the evaluator, and a sensory evaluation was conducted on a four-point scale based on the following scoring criteria (score). (Score) 5 points: Almost no whiteness. 4 points: Slight whiteness. 3 points: Feels slightly white. 2 points: Feels white. 1 point: Feels very white. (Evaluation criteria) A: The average score of 10 evaluators is 4.0 or higher. B: The average score of the 10 evaluators is 3.5 or more and less than 4.0. C: The average score of the 10 evaluators is 2.5 points or more but less than 3.5 points. D: The average score of the 10 evaluators is less than 2.5 points.

[0041] (water repellency) The evaluator applied 2 mg / cm2 of the product to the inside of the forearm using a fingertip with a finger cot attached. 2 After 30 minutes from application, a drop of water was gently dropped, and the state of the drop formed on the surface was photographed. Based on the shape of the drop, the surface was evaluated according to the following criteria. A: The contact angle is 75° or more. B: The contact angle is 60° or more and less than 75°. C: The contact angle is 20° or more and less than 60°. D: The contact angle is less than 20°.

[0042] (Storage stability) After preparing the oil-in-water emulsion cosmetic, it was stored for one week in a thermostatic chamber in which the temperature changed between -10°C and 10°C in one cycle every 24 hours, and then the state of the system was visually confirmed and evaluated according to the following criteria.

[0043] (Evaluation criteria) A: Almost the same as immediately after preparation. B: No significant change in condition was observed. C: A significant change in state was observed (coalescence of the oil phase, etc.). D: A uniform oil-in-water emulsion cosmetic was not obtained immediately after preparation.

[0044] Examples 1 to 4 and Comparative Examples 1 to 3 The oil-in-water emulsion cosmetics shown in Table 1 were prepared according to the soap emulsification method and evaluated according to the evaluation methods described above. The results are shown in Table 1. The specific manufacturing procedures are as follows. (1) Components 1 to 13 are mixed and dissolved by heating at 80°C, and then cooled to room temperature to prepare oil phase (a). (2) Components 17 to 23 are mixed to prepare aqueous phase (b). (3) At room temperature, the aqueous phase (b) is added to the oil phase (a) and mixed using a test vacuum emulsifying mixer (PVQ-3UN, manufactured by Mizuho Kogyo Co., Ltd.) to prepare the cosmetic. This test vacuum emulsifying mixer can be equipped with three types of mixers (a dispersing mixer, a scraping mixer, and a homogenizing mixer). The diameters of the mixing blades are 39 mm for the dispersing mixer, 140 mm for the scraping mixer, and 36 mm for the homogenizing mixer. The types of mixers used during mixing and the peripheral speeds of the mixing blades are shown in Table 1.

[0045] Comparative Example 4 The oil-in-water emulsion cosmetics shown in Table 1 were prepared according to the D-phase emulsification method and evaluated using the evaluation methods described above. The results are shown in Table 1. The specific production procedure is as follows. (1) Components 1 to 4 are mixed to prepare Phase D (a). (2) Components 5 to 8 are mixed, heated to 80°C and dissolved, and then cooled to room temperature to prepare oil phase (b). (3) Components 17 to 23 are mixed to prepare aqueous phase (c). (4) Using a test vacuum emulsifying mixer (PVQ-3UN, manufactured by Mizuho Kogyo Co., Ltd., dispersing mixer blade diameter: 39 mm), add the oil phase (b) little by little to the D phase (a) and mix at room temperature to prepare a gel-like emulsion, O / D phase (d). The peripheral speed of the mixer blade during mixing is as shown in Table 1. (5) The O / D phase (d) is mixed with the water phase (c) to prepare a cosmetic.

[0046] Comparative Example 5 The oil-in-water emulsion cosmetics shown in Table 1 were prepared according to the phase inversion temperature emulsification method and evaluated according to the evaluation methods described above. The results are shown in Table 1. The specific production procedure is as follows. (1) Components 1 to 16 are mixed and heated to 80°C to dissolve, thereby preparing oil phase (a). (2) Components 17 to 23 are mixed and heated to 80°C to dissolve, to prepare aqueous phase (b). (3) Using a test vacuum emulsifying mixer (PVQ-3UN, manufactured by Mizuho Kogyo Co., Ltd., disper mixer blade diameter: 39 mm), the water phase (b) is added little by little to the oil phase (a) while mixing, and the mixture is cooled to room temperature to prepare the cosmetic preparation. The peripheral speed of the mixing blade during mixing is as shown in Table 1.

[0047] [Table 1]

[0048] The oil-in-water emulsion cosmetics of Examples 1 to 4 had essentially the same composition as the oil-in-water emulsion cosmetics described in Reference 1, except for their low viscosity and specific range of oil droplet volume average particle diameter. They exhibited excellent sunscreen effects, water resistance (water repellency), storage stability, and washability with soap. Furthermore, they did not produce a white appearance when filled into a spray container and applied. In contrast, the oil-in-water emulsion cosmetic of Comparative Example 1, which had the same composition but small oil droplet size (volume average particle diameter) due to a high peripheral velocity during mixing, exhibited a strong white appearance upon application. Furthermore, even when prepared using the same soap emulsification method as in Examples 1 to 4, the oil-in-water emulsion cosmetic of Comparative Example 2, which had a pH adjusted to 7.5, did not produce a white appearance when applied immediately after preparation and had excellent water repellency, but its stability over time was poor. The oil-in-water emulsion cosmetic of Comparative Example 3, which used a higher fatty acid salt obtained by neutralizing a solid higher fatty acid, failed to produce a uniform emulsion.

[0049] The oil-in-water emulsion cosmetic of Comparative Example 4, which was prepared using the D-phase emulsification method, had small oil droplets (volume average particle diameter) of 0.2 μm, and was noticeably white when applied. The oil-in-water emulsion cosmetic of Comparative Example 5, which was prepared using the phase inversion temperature emulsification method, had a transparent appearance with extremely small oil droplets (volume average particle diameter) of 0.1 μm, and was not perceived as white when applied, but had significantly poor water repellency due to the influence of the large amount of hydrophilic nonionic surfactant blended in the formulation.

[0050] Example 5 <Oil-in-water emulsion cosmetics for base use> The oil-in-water emulsion cosmetics for foundation shown in Table 2 were prepared according to the soap emulsification method in accordance with the following manufacturing procedure as in Example 1, and evaluated using the evaluation methods described above. The results are shown in Table 2. (1) Components 1 to 5 are mixed, heated to 80°C and dissolved, and then cooled to room temperature to prepare oil phase (a). (2) Components 6 to 14 are mixed to prepare aqueous phase (b). (3) At room temperature, the aqueous phase (b) is added to the oil phase (a) and mixed using a test vacuum emulsifying mixer (PVQ-3UN, manufactured by Mizuho Kogyo Co., Ltd., disper blade diameter: 39 mm) to prepare the cosmetic preparation. The peripheral speed of the mixer blade during mixing is as shown in Table 2.

[0051] [Table 2]

[0052] The oil-in-water emulsion cosmetic for foundation use in Example 5 was not white when applied, had excellent water repellency and stability, and had a smooth feel due to the inclusion of a (vinyl dimethicone / methicone silsesquioxane) crosspolymer. Furthermore, the inclusion of an acrylates copolymer, which is known as a film-forming agent, provided even better water resistance. [Industrial Applicability]

[0053] According to the present invention, there is provided an oil-in-water emulsion cosmetic that maintains the sunscreen effect, excellent water resistance (water repellency), excellent storage stability, and excellent washability with soap, which are characteristics of the oil-in-water emulsion cosmetic described in Document 1, while not producing a white cast when filled into a spray container and applied to the skin.

Claims

1. The present invention relates to a composition comprising (A) a salt of a higher fatty acid component containing a liquid higher fatty acid, and (B) an oil-soluble ultraviolet absorber, and is essentially free of hydrophilic surfactants other than (A) the salt of the higher fatty acid component, and has a pH of 8.0 to 9.5, a volume average particle diameter of oil droplets of 2 to 50 μm, and a viscosity indicated at 25°C of 100 [(mPa s) × (g / cm ３ ) or less.

2. 2. The oil-in-water emulsion cosmetic according to claim 1, wherein the volume average particle size is 3 to 40 μm.

3. 3. The oil-in-water emulsion cosmetic according to claim 1, wherein the liquid higher fatty acid is one or more selected from the group consisting of oleic acid, linoleic acid, linolenic acid, arachidonic acid, hexyldecanoic acid, and isostearic acid.

4. 3. The aqueous cosmetic preparation according to claim 1, which is a spray-type cosmetic preparation.

5. The viscosity display value is 10 [(mPa s) × (g / cm ３ 3. The aqueous cosmetic preparation according to claim 1, wherein the total amount of the water-soluble polymer is 0.1 or less.

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