Oil-in-water emulsion composition

Abstract

The problem to be solved by the present invention is to provide: an oil-in-water emulsion composition with which elasticity is felt from inside the skin without producing stickiness, and which has an outstanding skin improving effect in terms of wrinkling, etc., through long-term use; and a sheet-shaped topical agent in which a sheet-shaped substrate has been impregnated with the abovementioned composition. As a method thereof, it is possible to improve wrinkling through long-term use while ensuring firmness of the skin from the inside as a result of: an oil-in-water emulsion composition which contains the five components of a vinyl acetate-vinyl pyrrolidone copolymer, a polyvinyl alcohol, a polyalcohol serving as a moisturizing agent, retinol (an oil-soluble drug), and oil; and a sheet-shaped topical agent in which a sheet-shaped substrate has been impregnated with the abovementioned composition.

Description

Related Applications

[0001] The present invention is based on the priority of Japanese Patent Application No. 2020-033915 (filed February 28, 2020), the entire contents of which are incorporated herein by reference. [Technical Field]

[0002] The present invention relates to an oil-in-water emulsion composition and a sheet-like external skin preparation in which said composition is impregnated into a sheet-like substrate, and in particular to an improvement in the moisturizing effect and firmness of the skin, and a plump feeling that makes the skin firm from the inside. [Background technology]

[0003] In recent years, many formulations have been developed that can make the skin feel firmer, as well as formulations that have the effect of smoothing wrinkles (for example, Patent Publication No. 3920797). Many of these formulations contain water-soluble or oil-soluble film-forming agents, but these cosmetics can become sticky when the solvent evaporates and the polymer coats the skin, resulting in an unpleasant feel when used. Furthermore, even if a firming sensation like a film is felt on the outside, it is difficult to feel a plump, firm feeling from within. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3920797 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in consideration of the problems of the prior art, and an object of the present invention is to provide an oil-in-water emulsion composition that does not cause stickiness, provides a feeling of firmness from within the skin, and is effective in improving skin conditions such as wrinkles with long-term use, and a sheet-like topical skin preparation in which the composition is impregnated into a sheet-like substrate. [Means for solving the problem]

[0006] As a result of intensive research conducted by the present inventors to achieve the above-mentioned object, it was found that by combining a specific film-forming agent and blending a polyhydric alcohol as a moisturizing agent with an oil-soluble drug, it is possible to obtain an oil-in-water emulsion composition that has low viscosity but provides a plump, firm feeling from both the inside and outside of the skin and also has an excellent wrinkle-reducing effect, and this has led to the completion of the present invention. That is, the oil-in-water emulsion composition of the present invention is polyvinyl alcohol, Vinyl acetate-vinylpyrrolidone copolymer, polyhydric alcohols, Oil-soluble drugs, Contains oil, The viscosity is 2000 mPa·s or less, It is characterized by an emulsified particle size of 5 μm or less. In the oil-in-water emulsion composition, the blending ratio of polyvinyl alcohol to vinyl acetate-vinylpyrrolidone copolymer is within the range of 1:2 to 2:1. The oil-in-water emulsion composition has a mass ratio of (total of polyvinyl alcohol and vinyl acetate-vinylpyrrolidone copolymer):(polyhydric alcohol) of 1:50 to 1:110, and contains 0.05 to 1.0 mass% of polyvinyl alcohol and 0.05 to 1.0 mass% of vinyl acetate-vinylpyrrolidone copolymer. It is also preferable to prepare a sheet-type external skin preparation by impregnating a sheet-type substrate with the oil-in-water emulsion composition. Furthermore, the oil-soluble drug contained in the oil-in-water emulsion composition is preferably retinol. [Effects of the Invention]

[0007] According to the present invention, by blending a polyhydric alcohol and an oil-soluble drug with a combination of specific film-forming agents, it is possible to obtain an emulsion composition that gives a feeling of plumpness and firmness from the inside and outside of the skin without causing stickiness, and that is also expected to have a wrinkle-reducing effect. DETAILED DESCRIPTION OF THE INVENTION

[0008] (a) Polyvinyl alcohol The polyvinyl alcohol used in the emulsion composition of the present invention is not particularly limited by its molecular weight, etc. Polyvinyl alcohol is obtained by hydrolyzing polyvinyl acetate and is a linear polymer of vinyl alcohol. The polyvinyl alcohol used in the present invention preferably has a degree of saponification (mol%) of about 85 to 90.

[0009] Examples of polyvinyl alcohols commercially available as cosmetic raw materials include Kuraray Poval (manufactured by Kuraray Co., Ltd.), Denka Poval (manufactured by Denka Co., Ltd.), Poval (manufactured by Nippon Vaccination & Poval Co., Ltd.), and Gohsenol. TM (Mitsubishi Chemical Corporation), etc.

[0010] In the present invention, polyvinyl alcohol can form a firm film and is expected to be highly effective in improving skin firmness. In addition, together with the vinyl acetate-vinylpyrrolidone copolymer, it can provide sufficient film strength and a comfortable fit to the skin.

[0011] The amount of polyvinyl alcohol blended in the emulsion composition of the present invention is 0.05 to 1.0% by mass of the total amount of the composition, preferably 0.1 to 0.5% by mass, and more preferably 0.3 to 0.5% by mass. If the amount of polyvinyl alcohol blended is less than 0.05% by mass, the effect of film formation may not be exerted, and if it exceeds 1.0% by mass, usability tends to deteriorate.

[0012] (b) Vinyl acetate-vinylpyrrolidone copolymer The vinyl acetate-vinylpyrrolidone copolymer used in the present invention is a copolymer of vinylpyrrolidone and vinyl acetate, and is an amphiphilic copolymer with an average molecular weight of 50,000 to 60,000.

[0013] Commercially available vinyl acetate-vinylpyrrolidone copolymers used as cosmetic raw materials include, for example, PVP / VA S-630 (Ashland Specialty Ingredients) and PVA-6450-Acorn M (Osaka Organic Chemical Industry Co., Ltd.).

[0014] In the present invention, although the film-forming ability of vinyl acetate-vinylpyrrolidone copolymer is slightly inferior to that of polyvinyl alcohol, it has a high affinity for the skin and can provide a feeling of adhesion.

[0015] The amount of vinyl acetate-vinylpyrrolidone copolymer blended in the emulsion composition of the present invention is 0.05 to 1.0% by mass of the total amount of the composition, preferably 0.1 to 0.5% by mass, and more preferably 0.3 to 0.5% by mass. If the amount of vinyl acetate-vinylpyrrolidone copolymer blended is less than 0.05% by mass, it may be difficult to feel a firming sensation from within, and if it exceeds 1.0% by mass, it may feel oily.

[0016] In the emulsion composition of the present invention, the blending ratio of (a) polyvinyl alcohol to (b) vinyl acetate-vinylpyrrolidone copolymer is preferably 1:2 to 2:1, and more preferably 0.8:1 to 1:0.8.

[0017] (c) Moisturizer The moisturizing agent used in the emulsion composition of the present invention is preferably a polyhydric alcohol, such as propylene glycol, polyethylene glycol, dipropylene glycol, glycerin, 1,3-butylene glycol, xylitol, sorbitol, maltitol, ethylene glycol, or trimethylolpropane. One or more of these may be contained, and dipropylene glycol, glycerin, and 1,3-butylene glycol are particularly preferred. The moisturizing agent used in the present invention gels the film formed on the skin by the vinyl acetate-vinylpyrrolidone copolymer and polyvinyl alcohol, contributing to the formation of a moist, flexible gel-like film.

[0018] The amount of the moisturizing agent blended in the emulsion composition of the present invention is 10 to 25% by mass, preferably 10 to 20% by mass, and more preferably 10 to 17% by mass, based on the total amount of the composition. If the amount of moisturizer is less than 10% by mass, the moisturizer may not be effective, and if it exceeds 25% by mass, resistance may be felt with the fingers when spreading it on the skin, and the product may subjectively feel heavy when spread.

[0019] (d) Oil-soluble drugs Oil-soluble drugs used in the emulsion composition of the present invention include oil-soluble vitamins, such as retinol, retinolate derivatives (retinol acetate, retinol palmitate, etc.), vitamin E, vitamin E derivatives (vitamin E acetate, etc.), vitamin Ds, and vitamin K. Among these, retinol is particularly preferred as it improves skin firmness and reduces wrinkles. Retinol is an oil-soluble organic compound that is a nutrient called vitamin A1 and is approved as an active ingredient in quasi-drugs to reduce wrinkles. Retinol alone is highly unstable and highly vulnerable to heat, light, and oxygen.

[0020] The amount of retinol blended in the emulsion composition of the present invention is 0.01 to 0.1% by mass, and preferably 0.01 to 0.06% by mass. An appropriate blend amount can be added taking into consideration drug stability.

[0021] In order to improve the pharmaceutical stability of retinol, silicone oil, hydrocarbon oil, ester oil, etc. can be blended as oil components other than retinol. Specific examples include linear polysiloxanes such as dimethylpolysiloxane and diphenylpolysiloxane; cyclic polysiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and dodecamethylcyclohexasiloxane; silicone oils such as various modified polysiloxanes (amino-modified polysiloxane, polyether-modified polysiloxane, alkyl-modified polysiloxane, fluorine-modified polysiloxane, etc.); liquid paraffin, ozokerite, and squalane. , pristane, paraffin, ceresin, squalene, petrolatum, microcrystalline wax and other hydrocarbon oils; isopropyl myristate, cetyl octanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, lanolin acetate, isocetyl stearate, isocetyl isostearate, Cholesteryl 12-hydroxystearate, ethylene glycol di-2-ethylhexanoate, dipentaerythritol fatty acid ester, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, glycerin di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, glycerin trioctanoate, glycerin triisopalmitate, trimethylolpropane triisostearate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, trimethylolpropane triisostearate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, trimethylolpropane triisostearate synthetic ester oils such as glycerin ristate, tri-2-heptylundecanoic acid glyceride, castor oil fatty acid methyl ester, oleyl oleate, acetoglyceride, 2-heptylundecyl palmitate, diisobutyl adipate, N-lauroyl-L-glutamic acid-2-octyldodecyl ester, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, 2-ethylhexyl succinate, and triethyl citrate;Other examples include vegetable oils such as avocado oil, camellia oil, macadamia nut oil, corn oil, olive oil, rapeseed oil, sesame oil, persic oil, wheat germ oil, camellia oil, castor oil, linseed oil, safflower oil, cottonseed oil, perilla oil, soybean oil, peanut oil, grapeseed oil, almond oil, tea seed oil, kaya oil, rice bran oil, Chinese tung oil, Japanese tung oil, jojoba oil, and germ oil; and animal oils such as turtle oil, egg yolk oil, and mink oil. In particular, methylphenyl silicone oil, pentaerythrityl tetra-2-ethylhexanoate (for example, "RA-PE-408" (manufactured by Nippon Fine Chemical Co., Ltd.)) is useful for the pharmaceutical stability of retinol.

[0022] Furthermore, the oil-in-water emulsion composition according to the present invention contains water as an essential component.

[0023] In addition to the above-mentioned essential components, the emulsion composition of the present invention can contain other components that are usually used in emulsion compositions of cosmetics, pharmaceuticals, etc., such as powder components, water-soluble polymers, thickeners, ultraviolet absorbers, sequestering agents, sugars, amino acids, organic amines, polymer emulsions, pH adjusters, antioxidants, antioxidant aids, fragrances, etc., within quantitative and qualitative ranges that do not impair the effects of the present invention.

[0024] Examples of the powder component include inorganic powders (e.g., talc, kaolin, mica, sericite, muscovite, phlogopite, synthetic mica, lepidolite, biotite, vermiculite, magnesium carbonate, calcium carbonate, aluminum silicate, barium silicate, calcium silicate, strontium silicate, metal tungstate, magnesium, silica, zeolite, barium sulfate, calcined calcium sulfate, calcium phosphate, fluoroapatite, hydroxyapatite, ceramic powder, metal soaps (e.g., zinc myristate, calcium palmitate, stearic acid, hydroxyapatite ... Aluminum phosphate, boron nitride, etc.); organic powders (e.g., polyamide resin powder (nylon powder), polyethylene powder, polymethyl methacrylate powder, polystyrene powder, styrene-acrylic acid copolymer resin powder, benzoguanamine resin powder, polytetrafluoroethylene powder, cellulose powder, etc.); inorganic white pigments (e.g., titanium dioxide, zinc oxide, etc.); inorganic red pigments (e.g., iron oxide (red iron), iron titanate, etc.); inorganic brown pigments (e.g., gamma-iron oxide, etc.); inorganic yellow pigments (e.g., yellow iron oxide, yellow ochre, etc.); inorganic black pigments (e.g., black Iron oxide, low-order titanium oxide, etc.); inorganic purple pigments (e.g., mango violet, cobalt violet, etc.); inorganic green pigments (e.g., chromium oxide, chromium hydroxide, cobalt titanate, etc.); inorganic blue pigments (e.g., ultramarine, iron blue, etc.); pearl pigments (e.g., titanium oxide coated mica, titanium oxide coated bismuth oxychloride, titanium oxide coated talc, colored titanium oxide coated mica, bismuth oxychloride, fish scale foil, etc.); metal powder pigments (e.g., aluminum powder, copper powder, etc.); zirconium, barium or aluminum Examples of organic pigments include aluminum lakes (e.g., organic pigments such as Red No. 201, Red No. 202, Red No. 204, Red No. 205, Red No. 220, Red No. 226, Red No. 228, Red No. 405, Orange No. 203, Orange No. 204, Yellow No. 205, Yellow No. 401, and Blue No. 404, as well as Red No. 3, Red No. 104, Red No. 106, Red No. 227, Red No. 230, Red No. 401, Red No. 505, Orange No. 205, Yellow No. 4, Yellow No. 5, Yellow No. 202, Yellow No. 203, Green No. 3, and Blue No. 1); and natural pigments (e.g., chlorophyll, β-carotene, etc.).

[0025] Examples of natural water-soluble polymers include plant-derived polymers (e.g., gum arabic, tragacanth gum, galactan, guar gum, carob gum, karaya gum, carrageenan, pectin, agar, quince seed, algae colloid (cassow extract), starch (rice, corn, potato, wheat)); and microbial-derived polymers (e.g., xanthan gum, dextran, succinoglucan, pullulan, etc.).

[0026] Examples of semi-synthetic water-soluble polymers include starch-based polymers (e.g., carboxymethyl starch, methylhydroxypropyl starch, etc.); cellulose-based polymers (methyl cellulose, ethyl cellulose, methylhydroxypropyl cellulose, hydroxyethyl cellulose, sodium cellulose sulfate, hydroxypropyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, crystalline cellulose, cellulose powder, etc.); and alginic acid-based polymers (e.g., sodium alginate, propylene glycol alginate, etc.).

[0027] Examples of synthetic water-soluble polymers include vinyl polymers (e.g., polyvinyl alcohol, polyvinylpyrrolidone, carboxyvinyl polymer, etc.); polyoxyethylene polymers (e.g., polyoxyethylene-polyoxypropylene copolymers of polyethylene glycol 20,000, 40,000, 60,000, 1,000,000, etc.); acrylic polymers (e.g., sodium polyacrylate, polyethyl acrylate, polyacrylamide, etc.); cationic polymers, etc.

[0028] Examples of thickeners include gum arabic, carrageenan, karaya gum, tragacanth gum, carob gum, quince seed, casein, dextrin, gelatin, sodium pectinate, sodium allaginate, methylcellulose, ethylcellulose, sodium carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, carboxyvinyl polymer, alkyl-modified carboxyvinyl polymer, locust bean gum, guar gum, tamarind gum, dialkyldimethylammonium cellulose sulfate, xanthan gum, gellan gum, aluminum magnesium silicate, bentonite, hectorite, AlMg silicate (Bee Gum), Laponite, and silicic anhydride.

[0029] Examples of the ultraviolet absorber include benzoic acid-based ultraviolet absorbers (e.g., para-aminobenzoic acid (hereinafter abbreviated as PABA), PABA monoglycerin ester, N,N-dipropoxy PABA ethyl ester, N,N-diethoxy PABA ethyl ester, N,N-dimethyl PABA ethyl ester, N,N-dimethyl PABA butyl ester, N,N-dimethyl PABA ethyl ester, etc.); anthranilic acid-based ultraviolet absorbers (e.g., homomenthyl-N-acetylanthranilate, etc.); salicylic acid-based ultraviolet absorbers (e.g., amyl salicylate, menthyl salicylate, homomenthyl salicylate, octyl salicylate, phenyl salicylate, benzyl salicylate, p-isopropanol phenyl salicylate, etc.); cinnamic acid-based ultraviolet absorbers (e.g., octyl cinnamate, ethyl-4-isopropyl cinnamate, methyl-2,5-diisopropyl cinnamate, ethyl-2,4-diisopropyl cinnamate, etc.); Cinnamate, methyl-2,4-diisopropylcinnamate, propyl-p-methoxycinnamate, isopropyl-p-methoxycinnamate, isoamyl-p-methoxycinnamate, octyl-p-methoxycinnamate (2-ethylhexyl-p-methoxycinnamate), 2-ethoxyethyl-p-methoxycinnamate, cyclohexyl-p-methoxycinnamate, ethyl-α-cyano-β-phenylcinnamate, 2-ethylhexyl Examples of suitable benzotriazoles include silyl-α-cyano-β-phenylcinnamate, glyceryl mono-2-ethylhexanoyl-diparamethoxycinnamate, etc.; pyridazine derivatives (dimorpholinopyridazine); 3-(4'-methylbenzylidene)-d,l-camphor, 3-benzylidene-d,l-camphor; 2-phenyl-5-methylbenzoxazole; 2,2'-hydroxy-5-methylphenylbenzotriazole; 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole; 2-(2'-hydroxy-5'-methylphenyl)benzotriazole; dibenzalazine; dianisoylmethane; 4-methoxy-4'-t-butyldibenzoylmethane; 5-(3,3-dimethyl-2-norbornylidene)-3-pentan-2-one, etc.

[0030] Examples of sequestering agents include 1-hydroxyethane-1,1-diphosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid tetrasodium salt, disodium edetate, trisodium edetate, tetrasodium edetate, sodium citrate, sodium polyphosphate, sodium metaphosphate, gluconic acid, phosphoric acid, citric acid, ascorbic acid, succinic acid, edetic acid, and trisodium ethylenediaminehydroxyethyltriacetate.

[0031] Examples of amino acids include neutral amino acids (e.g., threonine, cysteine, etc.), basic amino acids (e.g., hydroxylysine, arginine, etc.), etc. Examples of amino acid derivatives include sodium acyl sarcosine (sodium lauroyl sarcosine), acyl glutamate, acyltaurate, sodium acyl β-alanine, glutathione, pyrrolidone carboxylic acid, trimethylglycine, etc.

[0032] Examples of organic amines include monoethanolamine, diethanolamine, triethanolamine, morpholine, triisopropanolamine, 2-amino-2-methyl-1,3-propanediol, and 2-amino-2-methyl-1-propanol.

[0033] Examples of pH adjusters include buffers such as lactic acid-sodium lactate, citric acid-sodium citrate, succinic acid-sodium succinate, etc. Examples of antioxidants include δ-tocopherol, dibutylhydroxytoluene, butylhydroxyanisole, gallic acid esters, etc.

[0034] Examples of antioxidant aids include phosphoric acid, citric acid, ascorbic acid, maleic acid, malonic acid, succinic acid, fumaric acid, cephalin, hexametaphosphate, phytic acid, and ethylenediaminetetraacetic acid.

[0035] Other ingredients that can be added include, for example, preservatives (ethylparaben, butylparaben, phenoxyethanol, etc.); water-soluble whitening agents (for example, arbutin, tranexamic acid, potassium 4-methoxysalicylate, ellagic acid, ascorbic acid, ascorbic acid glucoside, acorbic acid derivatives such as magnesium ascorbyl phosphate, nicotinamide, etc.); enhancers (for example, royal jelly, photosensitizers, cholesterol derivatives, etc.); blood circulation promoters (for example, nonyl valerinamide, nicotinic acid benzyl ester, nicotinic acid β-butoxyethyl tincture, capsaicin, zingerone, cantharides tincture, ichthammol, tannic acid, inositol hexanicotinate, cyclandelate, cinnarizine, tolazoline, acetylcholine, verapamil, cepharanthine, etc.; antiseborrheic agents (e.g., sulfur, thianthol, etc.); anti-inflammatory agents (e.g., glycyrrhizinate, salicylic acid derivatives, hinokitiol zinc oxide, allantoin, thiotaurine, hypotaurine, etc.), vitamin B6 tripalmitate, vitamin B6 dioctanoate, vitamin B2, vitamin B2 derivatives, vitamin B12, vitamin B15, vitamin B15 derivatives, etc.

[0036] The oil-in-water emulsion composition of the present invention is preferably produced by a method including the following steps (X) and (Y). (X): A process in which a hydrophilic nonionic surfactant is added to a moisturizer, and then oil is added to the mixture to emulsify it. (Y): A step of, after step (X), diluting the emulsion composition by adding water to the emulsion composition or by adding the emulsion composition to an aqueous phase to form an oil-in-water emulsion composition.

[0037] The emulsification method of the present invention is a method in which, instead of a typical oil-water system, a surfactant and oil are added to a moisturizing agent containing glycerin or the like to form liquid crystals, and water is then added to stabilize them. In this method, (f) a hydrophilic nonionic surfactant is dissolved in an aqueous solvent and then emulsified by adding an oil component. This results in a low interfacial tension between the oil and aqueous solvent, allowing even hydrophilic nonionic surfactants with low surface activity to be easily adsorbed to the interface with minimal stirring. Furthermore, since no heat application is required, the manufacturing process is simplified and even heat-sensitive oil-soluble drugs (e.g., retinol) can be stably incorporated. Therefore, in this manufacturing method, all steps are preferably carried out at room temperature (5 to 40°C) to stably incorporate the oil-soluble drug (retinol). Furthermore, by adding water later, an extremely stable oil-in-water emulsion composition can be obtained that has low viscosity, a non-sticky, pleasant feel, small particle size, and good uniformity. This method achieves an average emulsion particle size of 5 μm or less.

[0038] The hydrophilic nonionic surfactant (f) added in step (X) is not particularly limited as long as it is a hydrophilic nonionic surfactant typically used in topical skin preparations. Preferred examples include POE-alkyl ethers such as POE-lauryl ether, POE-oleyl ether, POE-sterial ether, POE-behenyl ether, POE-2-octyldodecyl ether, and POE-cholestanol ether; Pluronic types such as Pluronic (registered trademark); and POE-POP-alkyl ethers such as POE·POP-cetyl ether, POE·POP-2-decyltetradecyl ether, POE·POP-monobutyl ether, POE·POP-hydrogenated lanolin, and POE·POP-glycerin ether.

[0039] In the present invention, the (f) hydrophilic nonionic surfactant can be used alone or in combination of two or more. The amount of the surfactant to be added varies depending on the intended efficacy and effect of the topical skin preparation, but is preferably 0.2 to 0.8% by mass, and particularly preferably 0.4 to 0.6% by mass, of the oil-in-water emulsion composition.

[0040] Regarding the quantitative relationship of the stable oil-in-water emulsion composition of the present invention, in step (X), the blending ratio of the oil to the water-soluble solvent is preferably 25:12 to 1:3, and the blending ratio of the water-soluble solvent to the hydrophilic nonionic surfactant is preferably 15:1 to 75:1. In step (Y), the ratio of the emulsified composition in step (X):water is in the range of 3:7 to 3:17.

[0041] In conventional emulsification methods, it has been difficult to prepare a stable oil-in-water emulsion composition when the oil phase component is present in a large amount. However, according to the method of the present invention, an oil-based emulsion composition is first prepared in a water-soluble solvent, and then water is added to the emulsion composition, thereby making it possible to stably prepare an oil-in-water emulsion composition with a large oil phase component.

[0042] Furthermore, in conventional emulsification methods, the viscosity increases and the feel becomes sticky as the oil phase component content increases. However, according to the method of the present invention, it is possible to obtain an oil-in-water emulsion composition that has low viscosity, is not sticky, and has a good feel even when the oil phase component content is high.

[0043] The oil-in-water emulsion composition of the present invention is suitable not only for use in the form of emulsion cosmetics, but also for use as a sheet-type topical skin preparation in which the emulsion composition is impregnated into a sheet-type substrate. In this case, the viscosity of the oil-in-water emulsion composition is preferably 800 to 2000 mPa·s (30°C), more preferably 900 to 1100 mPa·s (30°C). If the viscosity exceeds 2000 mPa·s, penetration into the substrate is poor. Conversely, if the viscosity is less than 800 mPa·s, the composition may drip from the substrate during use, or if the content of the composition is reduced to prevent dripping, the effect of the oil-soluble drug may not be fully exerted. The viscosity was measured at 30°C using a BL viscometer manufactured by Shibaura Semtech Co., Ltd. at 12 rpm for 1 minute.

[0044] The oil-in-water emulsion composition of the present invention can be impregnated into a sheet-like substrate in a sufficient amount, allowing the oil-soluble drug to fully exert its effects. Furthermore, the composition has good stability on the substrate, and there is no problem with stability over time. Because the emulsion particles obtained by the emulsification process of the present invention are fine, the oil-soluble drug is uniformly dispersed in the emulsion composition and easily penetrates into the sheet-like substrate.

[0045] When the oil-in-water emulsion composition according to the present invention is used as a sheet-type skin topical preparation, it is essential that the oil-in-water emulsion composition be impregnated into a sheet substrate. The amount of the composition to be impregnated into the sheet substrate varies depending on the material of the sheet substrate, but at least an amount sufficient to wet the entire sheet substrate with the composition is required. Specifically, the amount is 5 to 20 times, preferably 12 to 16 times, the mass of the sheet substrate.

[0046] By impregnating a sheet substrate with the oil-in-water emulsion composition of the present invention, it becomes possible to apply a larger amount per unit area of ​​skin. Furthermore, when the sheet is impregnated with the oil-soluble drug, the oil-soluble drug is more easily released into the skin when applied to the skin, and the amount absorbed by the skin is increased, compared to conventional emulsion-type cosmetics, etc., so greater effects can be expected.

[0047] The sheet-like substrate used when the oil-in-water emulsion composition of the present invention is used as a sheet-like external skin preparation is not particularly limited as long as it can absorb liquid and retain it between or on its surface, but nonwoven fabric is particularly preferred. Fiber materials that make up nonwoven fabric include cotton, rayon, pulp, hemp, acrylic, nylon, silk, polyamide, polyester, polyurethane, polypropylene, etc., and mixtures thereof, but cotton is particularly preferred because it has high penetration and retention properties of the composition and is pleasant to the touch.

[0048] The oil-in-water emulsion composition can be impregnated into a sheet substrate by known methods, such as dropping, spraying, pressurizing, and dipping. The sheet substrate can be used as is or folded, and one or more sheets can be used for impregnation.

[0049] The impregnated sheet-like substrate can be immediately sealed in an airtight container to produce a sheet-like topical skin preparation, but by placing it on a polyethylene terephthalate (PET) tray or the like and sealing it in an airtight, light-blocking bag, such as an aluminum-laminated package or a package with an inner PET coating, a sheet-like topical skin preparation with dramatically improved stability of the oil-soluble drug can be produced. PET is particularly suitable as it has low adsorption of oil-soluble drugs.

[0050] Even when packaged in this manner, the sheet-like skin preparation for external use can be impregnated with a large amount of the emulsified composition without dripping, and is therefore extremely easy to handle during the working process. In addition, when sealing and filling, it is preferable to seal in an inert gas such as argon gas or nitrogen gas to prevent the oil-soluble drug from being oxidized by oxygen. Furthermore, in order to maintain an oxygen-free state, it is also possible to fill the package with an oxygen-absorbing material or use a package made of a material with oxygen-absorbing ability.

[0051] The timing for impregnating the sheet-like substrate with the composition can be such that the user impregnates the sheet-like substrate at the time of use, but it is preferable to impregnate the sheet-like substrate with the composition before use by the user, as this ensures the stability of the oil-soluble drug and provides excellent usability and portability. The sheet-type external preparation for skin impregnated with the emulsion composition of the present invention is applied by adhering it to areas where wrinkles are noticeable, such as under the eyes or around the mouth, leaving it for an appropriate period of time, and then peeling it off. [Example]

[0052] The present invention will now be described in more detail with reference to test examples as examples, but the technical scope of the present invention is not limited to these examples. All blending amounts are in mass %.

[0053] Study on use as a sheet-type topical skin preparation First, the present inventors investigated the relationship between the type of thickener and usability in order to find a suitable thickener when using the emulsion composition of the present invention as a sheet-type external skin preparation. The results are shown in Table 1. <Usability evaluation method> The evaluation method for each usability is as follows. Mask falling off (during use) Seven expert panels evaluated the "slide-down" of a mask that was tightly fitted, and classified it as follows based on the number of panels who answered "it does not slide down." A: 5 or more people B: 3~4 people C:0~2 people · Familiarity Seven expert panels evaluated the "skin absorption (penetration, absorption) of the impregnated liquid remaining on the skin after removing the mask" and classified the products as follows based on the number of panels who answered "good absorption": A: 5 or more people B: 3~4 people C:0~2 people ·Firmness Seven expert panels evaluated the "skin firmness after the mask was removed and the impregnated liquid was absorbed into the skin," and the results were classified as follows based on the number of panels who answered "feeling firmness." A: 5 or more people B: 3~4 people C:0~2 people -Fluffiness Seven expert panels evaluated the "plumpiness of the skin after the mask is removed and the impregnated liquid is absorbed into the skin," and the results were categorized as follows based on the number of panels who answered "plumpiness." A: 5 or more people B: 3~4 people C:0~2 people

[0054] [Table 1] *1 RA-PE-408 (manufactured by Nippon Fine Chemical Co., Ltd.) *2 KF-56A (Shin-Etsu Kogyo Co., Ltd.) *3 PVP / VA S-630 (manufactured by Ashland Specialty Ingredients) *4 Gozenol TM EG-05 (Mitsubishi Chemical)

[0055] As can be seen from Table 1, when the amount of thickener (a) polyvinyl alcohol is increased, a certain degree of usability can be obtained with (a) polyvinyl alcohol alone, but when both (b) vinyl acetate-vinylpyrrolidone copolymer and (a) polyvinyl alcohol are added, good usability can be obtained with a lower content. Therefore, it is preferable that the oil-in-water emulsion composition of the present invention contains both (a) polyvinyl alcohol and (b) vinyl acetate-vinylpyrrolidone copolymer as thickeners.

[0056] Next, the blending ratios of (a) polyvinyl alcohol and (b) vinyl acetate-vinylpyrrolidone copolymer were investigated. The results are shown in Table 2.

[0057] [Table 2] *1 RA-PE-408 (manufactured by Nippon Fine Chemical Co., Ltd.) *2 KF-56A (Shin-Etsu Kogyo Co., Ltd.) *3 PVP / VA S-630 (manufactured by Ashland Specialty Ingredients) *4 Gozenol TM EG-05 (Mitsubishi Chemical)

[0058] As shown in Table 2, cosmetics with good usability were obtained when the blending amounts of (a) polyvinyl alcohol and (b) vinyl acetate-vinylpyrrolidone were each up to 0.5% by mass. Furthermore, no significant changes in usability were observed when the blending amounts of (a) polyvinyl alcohol and (b) vinyl acetate-vinylpyrrolidone were between 0.1 and 0.5% by mass, demonstrating their stability.

[0059] Furthermore, the inventors investigated the amount of (c) moisturizer added. The results are shown in Table 3.

[0060] [Table 3] *1 RA-PE-408 (manufactured by Nippon Fine Chemical Co., Ltd.) *2 KF-56A (Shin-Etsu Kogyo Co., Ltd.) *3 PVP / VA S-630 (manufactured by Ashland Specialty Ingredients) *4 Gozenol TM EG-05 (Mitsubishi Chemical)

[0061] Table 3 shows that (c) when the amount of polyhydric alcohol used as a moisturizer exceeds 20% by mass of the total composition, compatibility tends to be somewhat poor. When (c) the amount of moisturizer is 10% by mass or more, good usability is obtained even with two types of polyhydric alcohol. A mass ratio of (a) polyvinyl alcohol and (b) vinyl acetate-vinylpyrrolidone copolymer: (c) polyhydric alcohol used as a moisturizer) of 1:50 to 1:110 is preferable for usability.

[0062] [Formulation Example 1] Sheet-type topical skin preparation (1) Retinol 0.05 (2) Tocopheryl acetate 0.1 (3) Stearyl Glycyrrhetinate 0.1 (4) Squalane 0.1 (5) Pentaerythritol tetra-2-ethylhexanoate 10.0 (6) Methylphenylpolysiloxane 10.0 (7) POE(60) hydrogenated castor 0.5 (8) Glycerin 5.0 (9) 1,3-butylene glycol 7.0 (10) Dipropylene glycol 5.0 (11) Carboxyvinyl polymer 0.1 (12) Xanthan gum 0.05 (13) Dibutylhydroxytoluene 0.05 (14) EDTA-3Na 0.02 (15) Potassium hydroxide 0.02 (16) Methylparaben, appropriate amount (17) Phenoxyethanol, appropriate amount (18) Ethyl alcohol 3.0 (19) Vinyl acetate-vinylpyrrolidone copolymer 0.3 (20) Polyvinyl alcohol 0.3 (21) Angelica keiskei extract 0.1 (22) Olive Leaf Extract 0.1 (23) Caffeine 0.1 (24) Betaine 5.0 (25) Potassium methoxysalicylate 1.0 (26) Nicotinamide 5.0 (27) Remaining ion-exchange water (Production method) (7) is added to (8) to (10) and dissolved. (1) to (6) are added to this, and emulsification is carried out using a homomixer. A solution of (11) to (27) is added to the resulting emulsion to obtain an oil-in-water emulsion composition. This is impregnated into a cotton nonwoven fabric, placed in a PE pouch, and sealed in the pouch together with argon gas.

[0063] [Formulation Example 2] Sheet-type topical skin preparation (1) Retinol palmitate 0.1 (2) Tocopheryl acetate 0.1 (3) Oil-soluble licorice extract 0.1 (4) Squalane 0.1 (5) Glycerin tri-2-ethylhexanoate 10.0 (6) Methylphenylpolysiloxane 5.0 (7) POE(60) hydrogenated castor oil 0.5 (8) Glycerin 5.0 (9) 1,3-butylene glycol 7.0 (10) Dipropylene glycol 8.0 (11) Xylitol 2.0 (12) Alkyl-modified carboxyvinyl polymer 0.2 (13) Xanthan gum 0.05 (14) Dibutylhydroxytoluene 0.05 (15) EDTA-3Na 0.02 (16) Potassium hydroxide 0.02 (17) Methylparaben (appropriate amount) (18) Phenoxyethanol, appropriate amount (19) Ethanol 2.0 (20) Vinyl acetate-vinylpyrrolidone copolymer 0.05 (21) Polyvinyl alcohol 0.05 (22) Safflower flower extract 0.1 (23) Rose water 0.1 (24) Jujube Fruit Extract 0.05 (25) PEG / PPG-14 / 7 dimethyl ether 0.5 (26) Tranexamic acid methylamide hydrochloride 1.0 (27) Nicotinamide 5.0 (28) Remaining ion-exchange water (Production method) (7) is added to (8) to (10) and dissolved. (1) to (6) are added to this, and emulsification is carried out by homomixer treatment. A solution of (11) to (28) is added to the obtained emulsion to obtain an oil-in-water emulsion composition. A cotton nonwoven fabric is impregnated with this.

Claims

1. (a) 0.05 to 0.5% by mass of polyvinyl alcohol, (b) vinyl acetate / vinylpyrrolidone copolymer 0.05 to 0.5% by mass, (c) 10 to 20% by mass of a polyhydric alcohol, which is two or more selected from dipropylene glycol, glycerin, and 1,3-butylene glycol; (d) retinol 0.01 to 0.1% by mass, (e) 13.05 to 20.1% by mass of an oil that is at least one selected from pentaerythrityl tetraethylhexanoate, diphenylsiloxyphenyl trimethicone, squalane, methylphenylpolysiloxane, and glycerin tri-2-ethylhexanoate; an external skin preparation comprising an oil-in-water emulsion composition comprising Its viscosity is 2000 mPa s or less at 30°C, An external skin preparation comprising an oil-in-water emulsion composition characterized in that the particle size is 5 μm or less.

2. 2. The topical skin preparation comprising the oil-in-water emulsion composition according to claim 1, wherein the blending ratio of (a) polyvinyl alcohol to (b) vinyl acetate-vinylpyrrolidone copolymer is 1:2 to 2:

1.

3. 3. The topical skin preparation comprising the oil-in-water emulsion composition according to claim 1, wherein the mass ratio of (the sum of (a) polyvinyl alcohol and (b) vinyl acetate-vinylpyrrolidone copolymer):((c) polyhydric alcohol) is 1:50 to 1:

110.

4. 4. The external skin preparation according to claim 1, wherein the polyhydric alcohol (c) is one of three types: dipropylene glycol, glycerin, and 1,3-butylene glycol.

5. A sheet-like external preparation for skin, comprising a sheet-like substrate impregnated with an external preparation for skin comprising the oil-in-water emulsion composition according to any one of claims 1 to 4.

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