Emulsion composition

Abstract

To provide an emulsified composition having a good feeling of use in application, containing an oily base in an amount necessary for improving the occlusion of the skin and reducing the transpiration of water from the skin, and having both low irritation and storage stability.SOLUTION: (A) an oily base selected from the group consisting of hydrocarbons, fats and oils, fatty acids, higher alcohols, esters, and waxes, (B) a surfactant selected from the group consisting of hydrogenated lecithin, hydrogenated lysolecithin, and hydroxylated lecithin, (C) a solid oil, (D) water, and (E) The content of (A) the oily base is 15 to less than 40% by mass, A W / O emulsion composition in which a content of (B) a surface active agent is 0.5 to 5% by mass, a content of (C) a solid oil is 0.1 to 5% by mass, and a content of (D) water is 50 to 80% by mass, wherein the W / O emulsion composition is emulsified only with the surface active agent (B), and a nature-derived index (including water) calculated in conformity with ISO16128 is 90 or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an emulsion composition containing an oil that is liquid at room temperature as a main component. [Background technology]

[0002] In the treatment, prevention, or amelioration of symptoms caused by dry skin, various cosmetic oils have been used as bases to improve the occlusiveness of the skin and reduce moisture evaporation from the skin. However, when a composition containing a large amount of oil is applied to the skin, although it can prevent moisture evaporation from the skin, it causes a noticeable sticky feeling after application, which is problematic in terms of the feel when used.

[0003] To solve these problems, emulsion compositions such as emulsions and creams containing bases containing hydrocarbons, oils and fats, fatty acids, higher alcohols, esters, and waxes have been used. The use of a surfactant is essential in the production of such emulsion compositions, but many commonly used surfactants are skin irritants. Furthermore, to achieve sufficient skin occlusion and the effect of reducing moisture evaporation from the skin, it is necessary to increase the amount of the oily base. However, as the amount increases, the product becomes sticky after application, worsening the feel when used, and the types and amounts of surfactants required for emulsification increase.

[0004] Skin showing dryness symptoms has a weakened barrier function and is in a state of sensitivity to external stimuli, etc. For use by consumers with such sensitive skin, it is necessary to reduce the skin irritation of the emulsion composition. To achieve this, it is considered effective to use a surfactant with low skin irritation or to reduce the amount of surfactant used. However, since many surfactants with low skin irritation have weak emulsifying power, a stable emulsion system is often not obtained. Furthermore, even when the amount of surfactant used is reduced, problems such as reduced emulsion stability also occur.

[0005] W / O emulsion compositions are useful for achieving skin occlusion and reducing moisture evaporation from the skin, but it has been difficult to obtain compositions with stable temperature stability over time when the composition contains little oil. A known method for improving the stability of W / O emulsion compositions involves adding a gelling agent for a liquid oily component to a liquid oily base to form a gel, which is then mixed with water using a specific water-in-oil surfactant to emulsify (Patent Document 1). However, because the W / O emulsion compositions use an oily gelling agent such as a dextrin fatty acid ester as a gelling agent, they tend to be sticky, creating problems with the feel when used.

[0006] Patent Documents 2 and 3 also disclose emulsion compositions obtained using surfactants such as petrolatum, 1,3-butylene glycol, and lecithin, which has low skin irritation. However, the emulsion compositions in Patent Documents 2 and 3 use not only lecithin but also surfactants such as decaglyceryl monolaurate and N-coconut oil fatty acid acyl-L-arginine ethyl ester to emulsify oils such as petrolatum and jojoba oil, and the emulsion is produced by processing with a high-pressure homogenizer. However, special machinery such as a high-pressure homogenizer is required to obtain these emulsions, which poses a problem of lack of versatility when producing them.

[0007] Patent Document 4 describes a W / O type emulsion composition that contains an oily component consisting of liquid paraffin, squalane, and white petrolatum, and a high content of ceresin relative to the total mass of the emulsion composition, and uses polyglyceryl monooleate as an active agent.

[0008] Patent Document 5 describes a W / O type emulsion composition containing (A) petrolatum, (B) hydrogenated lecithin, (C) solid oil, (D) water, and (E) a water-soluble polymer, and a high-content petrolatum emulsion composition in which the content of (A) petrolatum is the highest among the emulsion compositions. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 3509108 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-72581 [Patent Document 3] Japanese Patent Application Laid-Open No. 2003-95956 [Patent Document 4] International Publication No. 2014 / 171507 Brochure [Patent Document 5] Patent Publication No. 2021-004194 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0010] An object of the present invention is to provide an emulsion composition that has a pleasant feel when applied, that contains an oily base in an amount necessary to improve the occlusiveness of the skin and reduce moisture evaporation from the skin, and that combines low irritation and storage stability. [Means for solving the problem]

[0011] The present inventors have found that the above-mentioned problems can be solved by providing a W / O type emulsion composition that contains (A) an oily base selected from the group consisting of hydrocarbons, oils and fats, fatty acids, higher alcohols, esters, and waxes in an amount necessary to reduce moisture loss from the skin, (B) a surfactant with low skin irritation selected from the group consisting of hydrogenated lecithin, hydrogenated lysolecithin, and hydroxylated lecithin, and that also contains (C) a solid oil, (D) water, and (E) a water-soluble polymer to improve the feel during use and the stability of the composition.

[0012] That is, the present invention provides a W / O type emulsion composition containing (A) an oily base selected from the group consisting of hydrocarbons, fats and oils, fatty acids, higher alcohols, esters, and waxes, (B) a surfactant selected from the group consisting of hydrogenated lecithin, hydrogenated lysolecithin, and hydroxide lecithin, (C) a solid oil, (D) water, and (E) a water-soluble polymer, wherein the content of the (A) oily base is 15 to less than 40% by mass, the content of the (B) surfactant is 0.5 to 5% by mass, the content of the (C) solid oil is 0.1 to 5% by mass, and the content of the (D) water is 50 to 80% by mass, and the emulsion composition is emulsified with only the (B) surfactant. The emulsion composition of the present invention has a natural origin index (including water) calculated in accordance with ISO 16128 of 90 or more, preferably 95 or more. The content of the (A) oily base is preferably 20 to 35% by mass, and the content of the (B) surfactant is preferably 0.5 to 3.5% by mass. The (C) solid oil is at least one selected from the group consisting of ceresin, hydrocarbons selected from paraffin and microcrystalline wax, waxes selected from candelilla wax, carnauba wax and beeswax, and saturated higher alcohols selected from cetanol, stearyl alcohol and behenyl alcohol, and the content of the (C) solid oil is preferably 0.5 to 3% by mass. The content of the (D) water is preferably 50 to 75% by mass. The (E) water-soluble polymer is preferably at least one polymer selected from the group consisting of cellulose-based polymers, vinyl-based polymers, acrylic acid-based polymers, microbial-derived polymers, and mucopolysaccharides. [Effects of the Invention]

[0013] The present invention provides an emulsion composition that contains an oily base in an amount necessary to improve skin occlusion and reduce moisture evaporation from the skin, yet spreads well, has a smooth application feel, provides sufficient moisture to the skin, has long-lasting and good moisturizing properties, and combines low irritation and storage stability. Furthermore, the emulsion composition of the present invention also has excellent moisturizing properties, making it useful as an emulsion composition for treating, preventing, or ameliorating symptoms caused by dry skin and / or diseases exhibiting symptoms caused by dry skin. Furthermore, it is useful as a composition for treating, preventing, or ameliorating symptoms such as atopic dermatitis. DETAILED DESCRIPTION OF THE INVENTION

[0014] The oily base (A) used in the present invention is selected from the group consisting of hydrocarbons, fats and oils, fatty acids, higher alcohols, esters, and waxes. Examples of hydrocarbons used as the oily base (A) in the present invention include petrolatum, squalane, liquid paraffin, hydrogenated polyisobutene, and polybutene. For example, petrolatum may be Chloratum V (Croda Japan Co., Ltd.) or Sunwhite P-150 (Nikko Rica Corporation). For example, squalane may be sugarcane-derived sugar squalane (NIKKOL Sugar Squalane: Nikko Chemicals Co., Ltd.), olive-derived squalane (vegetable squalane: Kishimoto Tokushu Kanyu Kogyosho Co., Ltd.), or shark-derived squalane (Maruha Nichiro Corporation). Liquid paraffin, also known as liquid paraffin, mineral oil, or white mineral oil, is a mixture of hydrocarbons obtained from petroleum through processes such as distillation and refining. A wide range of grades, from low to high viscosity, are available, including MORESCO Bioless U-7 (MORESCO Corporation). Hydrogenated polyisobutene, also known as light liquid isoparaffin, can be used in a variety of forms with different fluidities depending on the degree of polymerization, such as Pearleem from NOF Corporation. Polybutene is a mixture of isobutene and n-butene, a highly viscous liquid. Because it is compatible with oils and hydrocarbons, it is used as an oily base for adhesion and viscosity, such as refined polybutene HV-100F (Nippon Natural Products Co., Ltd.). When applied to the skin, a liquid at room temperature is preferred to ensure smooth application. In the present invention, room temperature refers to 25°C.

[0015] The oils and fats used as the oily base (A) in the present invention refer to ester compounds of naturally occurring fatty acids and glycerin, most of which are triglycerides, i.e., substances in which one glycerin unit is bound to three fatty acids. This is a general term for oils and fats obtained from animals and plants, and those that are liquid at room temperature are preferred. Examples of oils and fats that can be used include salad oil, corn oil, soybean oil, sesame oil, rapeseed oil, rice bran oil, camellia oil, safflower oil, cottonseed oil, sunflower oil, linseed oil, olive oil, peanut oil, almond oil, avocado oil, hazelnut oil, grapeseed oil, horse oil, peony oil, deer oil, and emu oil. Furthermore, for smooth application to the skin, those that are liquid at room temperature are preferred.

[0016] The fatty acids used as the oily base (A) in the present invention include saturated and unsaturated fatty acids. Saturated fatty acids are divided into lower fatty acids that are liquid at room temperature and higher fatty acids that are solid, depending on the number of carbon atoms. Unsaturated fatty acids and higher branched fatty acids are suitable for use because they are liquid at room temperature. Examples of unsaturated fatty acids include oleic acid (EXTRA OS-85, NOF Corporation) and linoleic acid (Linoleic Acid 90, NOF Corporation). Examples of higher branched fatty acids include isostearic acid (ISOSTEARIC ACID EX, Kokyu Alcohol Kogyo Co., Ltd.) and isopalmitic acid (ISOPALMITIC ACID KS, Nissan Chemical Industries Co., Ltd.). Furthermore, when applied to the skin, those that are liquid at room temperature are preferred to ensure smooth application.

[0017] The higher alcohol used as the oily base (A) in the present invention includes branched-chain alcohols. Examples of such alcohols include oleyl alcohol VP (oleyl alcohol, manufactured by Takakyu Alcohol Kogyo Co., Ltd.), Lisonol 16SP (hexyldecanol, manufactured by Takakyu Alcohol Kogyo Co., Ltd.), Lisonol 18SP (isostearyl alcohol, manufactured by Takakyu Alcohol Kogyo Co., Ltd.), Lisonol 20SP (octyldodecanol, manufactured by Takakyu Alcohol Kogyo Co., Ltd.), and Lisonol 24SP (decyltetradecanol, manufactured by Takakyu Alcohol Kogyo Co., Ltd.). Liquid alcohols are preferred at room temperature to ensure smooth application to the skin.

[0018] The esters used as the oily base (A) in the present invention are esters of fatty acids and alcohols, and include ester oils that are liquid at room temperature, such as hexadecyl isostearate (NIKKOL ICIS, Nikko Chemicals Co., Ltd.), isocetyl stearate (NIKKOL ICS-R, Nikko Chemicals Co., Ltd.), isopropyl isostearate (NIKKOL IPIS, Nikko Chemicals Co., Ltd.), octyldodecyl myristate (NIKKOL ODM, Nikko Chemicals Co., Ltd.), cetyl ethylhexanoate (NIKKOL CIO, Nikko Chemicals Co., Ltd.), diisopropyl sebacate (NIKKOL DIS, Nikko Chemicals Co., Ltd.), octyldodecyl lactate (Esterol LOD, National Mimatsu Co., Ltd.), and isopropyl myristate (Exsepar IPM, Kao Corporation). Furthermore, in order to achieve smoothness during application to the skin, esters that are liquid at room temperature are preferred.

[0019] The waxes used as the oily base (A) in the present invention include jojoba oil (Summit Oil Mills, Inc.), which is liquid at room temperature, and lanolin (refined lanolin, Nippon Fine Chemical Co., Ltd.), which is paste-like. Waxes that are liquid at room temperature are preferred in order to ensure smoothness when applied to the skin.

[0020] The content of the oily base (A) in the present invention is usually 15 to less than 40% by mass, preferably 15 to 35% by mass, and most preferably 20 to 35% by mass, of the total amount of the emulsion composition. The lower the amount of oil in the emulsion composition, the lighter and more refreshing the feel when used, but the effects of improving the occlusiveness of the skin and reducing water evaporation from the skin are reduced, and the skin cannot be sufficiently moisturized, making it difficult to maintain sustained, good moisturization.

[0021] The hydrogenated lecithin contained in the (B) surfactant with low skin irritation in the present invention is typically a hydrogenated soybean phospholipid or egg yolk lecithin. For example, hydrogenated soybean phospholipids include NIKKOL Resinol S-10 (PC content 25-30%), NIKKOL Resinol S-10M (PC content 55-65%), and NIKKOL Resinol S-10E (PC content 75-85%) (manufactured by Nikko Chemicals Co., Ltd.), as well as Basis LP-20H (manufactured by The Nisshin Oillio Group, Inc.) and COATSOME NC-21 (NOF Corporation). For example, hydrogenated egg yolk lecithin such as egg yolk lecithin PL-100P (Kewpie Corporation) can be used. Preferably, NIKKOL Resinol S-10 (PC content 25 to 30%), Basis LP-20H (manufactured by The Nisshin Oillio Group, Ltd.), and egg yolk lecithin PL-100P (Kewpie Corporation) can be used. More preferably, NIKKOL Resinol S-10 (PC content 25 to 30%) and egg yolk lecithin PL-100P (Kewpie Corporation) can be used. (B) Hydrogenated lysolecithin contained in surfactants is obtained by removing one fatty acid from lecithin, which has two fatty acids bonded to it, through enzymatic hydrolysis, and is more hydrophilic than lecithin. Examples of hydrogenated lysolecithin that can be used include NIKKOL Lecinol LL-20 (Nikko Chemicals Co., Ltd.) and LP70H (Nippon Fine Chemical Co., Ltd.). (B) Hydroxylated lecithin contained in surfactants is lecithin that has been made more hydrophilic by hydroxylating the unsaturated moieties of two fatty acids of lecithin. Products such as NIKKOL Lecithinol SH50 (Nikko Chemicals Co., Ltd.) can be used. Hydrogenated lecithin and hydrogenated lysolecithin are made by hydrogenating the double bonds of the fatty acids to improve their stability against heat and oxidation, thereby compensating for the odor and deterioration of lecithin. However, in the present invention, non-hydrogenated lecithin and lysolecithin can also be used.

[0022] The content of (B) surfactant is preferably 0.5 to 5% by mass, more preferably 0.5 to 3.5% by mass, and most preferably 0.5 to 3% by mass, based on the total amount of the emulsion composition. Since the emulsion composition of the present invention is emulsified using only the (B) surfactant, if the content of the surfactant is too low, the storage stability of the emulsion composition will be poor, and conversely, if the content is too high, the emulsion will be poor and a smooth composition will not be obtained.

[0023] The solid oil (C) used in the present invention may be any oily component that is solid at room temperature. Examples include hydrocarbons such as paraffin wax, ceresin wax, microcrystalline wax, and montan wax; waxes such as candelilla wax, beeswax, lanolin wax, carnauba wax, and Japan wax; oils and fats such as glyceryl tribehenate; higher fatty acids such as stearic acid, myristic acid, and behenic acid; and higher alcohols such as stearyl alcohol, cetyl alcohol, and behenyl alcohol. These may be used alone or in combination. Preferred examples of the solid oil (C) used in the present invention include ceresin wax, microcrystalline wax, candelilla wax, carnauba wax, cetyl alcohol, and behenyl alcohol. More preferred examples of the solid oil (C) used in the present invention include ceresin wax, microcrystalline wax, candelilla wax, and cetyl alcohol.

[0024] The total content of (C) solid oil is usually 0.1 to 5% by mass, preferably 0.5 to 5% by mass, and more preferably 0.5 to 3% by mass, based on the total amount of the emulsion composition. If the content of solid oil is too low, the emulsion composition becomes too soft and its storage stability deteriorates. On the other hand, if the content of solid oil is too high, the emulsion composition loses its smoothness, resulting in an emulsion composition with a poor texture when used.

[0025] The content of (D) water is 50 to 80% by mass, usually 55 to 80% by mass, preferably 55 to 70% by mass, and more preferably 55 to 65% by mass, based on the total amount of the emulsion composition. If the content of water in the emulsion composition is too low, the oil will feel sticky, and an emulsion composition with a good feel when used will not be obtained.

[0026] Examples of the water-soluble polymer (E) used in the present invention include cellulose-based polymers such as methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxyethylmethyl cellulose, and hydroxypropyl cellulose; vinyl-based polymers such as polyvinylpyrrolidone, polyethylene glycol, carboxyvinyl polymer, and polyvinyl methyl ether; acrylic acid-based polymers such as sodium polyacrylate, partially neutralized polyacrylic acid, and acrylic acid / methacrylic acid alkyl ester copolymers; microbial polymers such as xanthan gum, dextran, and pullulan; and mucopolysaccharides such as chondroitin sulfate, sodium chondroitin sulfate, hyaluronic acid, and sodium hyaluronate. These water-soluble polymers can be used alone or in combination of two or more.

[0027] (E) Water-soluble polymers include, among cellulose polymers, preferred are carboxymethyl cellulose and hydroxyethyl cellulose; among vinyl polymers, preferred are polyvinylpyrrolidone and carboxyvinyl polymer; among acrylic polymers, preferred are sodium polyacrylate and acrylic acid-methacrylic acid alkyl ester copolymers; among microbial polymers, preferred are xanthan gum and pullulan; and among mucopolysaccharides, preferred are hyaluronic acid and sodium hyaluronate. Among these, carboxyvinyl polymer, acrylic acid-methacrylic acid alkyl ester copolymer, xanthan gum, and sodium hyaluronate are particularly preferred.

[0028] The content of the (E) water-soluble polymer in the present invention is not particularly limited as long as the effects of the present invention are achieved, but it is usually 0.01 to 3 mass %, preferably 0.05 to 1.5 mass %, and most preferably 0.1 to 1 mass %, relative to the total amount of the emulsion composition.

[0029] The cosmetic of the present invention has a natural origin index (including water) calculated in accordance with ISO 16128 of 90 or more, preferably 95 or more. The raw ingredients are composed of environmentally friendly ingredients, and by incorporating renewable plant-based ingredients in particular, it is possible to develop cosmetics that are considerate of human health and the environment.

[0030] In addition to the above-mentioned components, other components commonly used in cosmetics can be appropriately blended into the emulsion composition of the present invention as needed, as long as they do not impair the objects and effects of the present invention. Furthermore, since the emulsion composition of the present invention contains a large amount of oils, the use of hydrogenated raw materials and the addition of antioxidants are particularly important from the standpoint of preventing oxidation. Examples of such components include oil-soluble polymers, polymer powders, alcohols, liquid oils and fats, ester oils, hydrocarbon oils, fatty acid esters, various pharmaceuticals, and organically modified clay minerals. Furthermore, useful ingredients such as whitening agents, anti-wrinkle agents, moisturizers, anti-inflammatory agents, antioxidants, preservatives, and vitamins can be appropriately blended as needed, but are not limited to these examples.

[0031] For example, whitening agents include vitamin C compounds such as placenta, arbutin, kojic acid, hydroquinone, ethyl ascorbic acid, sodium ascorbyl phosphate, magnesium ascorbyl phosphate, and ascorbic acid glucoside, as well as plant-derived ingredients such as licorice extract and Morus alba extract; and anti-wrinkle agents include ubiquinones such as coenzyme Q10, kinetin, argireline, acetylglucosamine, collagen, retinol, retinol palmitate, retinal, and retinoids. carboxylic acid, tocopheryl retinoate, β-carotene, tocopherol acetate; moisturizing agents include natural moisturizing factors such as polyethylene glycol, trehalose, heparinoids, collagen, elastin, urea, sodium pyrrolidone carboxylate, and ceramides such as ceramide 1, ceramide 2, ceramide 3, ceramide 4, ceramide 5, ceramide 6I, ceramide 6II, and ceramide 7; anti-inflammatory agents include licorice extract, stearyl glycyrrhizinate, dipotassium glycyrrhizinate, and glycyrrhizin. glycyrrhizinic acid derivatives such as monoammonium phosphate; glycyrrhetinic acid or its derivatives; allantoin or its derivatives; antioxidants such as tocopherol, disodium ethylenediaminetetraacetate dihydrate, sorbic acid, and sodium sulfite; preservatives such as parabens, benzoic acid, sodium dehydroacetate, phenoxyethanol, salicylic acid, propanediol, propylene glycol, butylene glycol, hexanediol, caprylyl glycol, and ethylhexylglycerin; vitamins such as vitamin B2 derivatives such as riboflavin, flavin mononucleotide, and flavin adenine dinucleotide; nicotinic acids such as methyl nicotinate, nicotinic acid, and nicotinamide; vitamin B1s such as thiamine hydrochloride and thiamine monophosphate; vitamin B6s such as pyridoxine hydrochloride, pyridoxal hydrochloride, pyridoxine cyclic phosphate, and pyridoxamine hydrochloride; and vitamin B12s such as cyanocobalamin and deoxyadenosylcobalamin.

[0032] The method for producing the emulsion composition of the present invention is not particularly limited and may be a commonly used method. The oil phase and the aqueous phase are heated and dissolved, and then mixed with stirring to emulsify. After emulsification, the mixture is cooled to room temperature while stirring to obtain an emulsion composition. Mixing is performed using an emulsifying machine such as a homomixer, colloid mill, homogenizer, or propeller mixer, depending on the type and amount of emulsifier, the purpose of use of the formulation, etc.

[0033] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. Contents are expressed in mass % unless otherwise specified.

[0034] Before describing the examples, the evaluation test methods used in the present invention will be described.

[0035] (1) State of the emulsion composition A practical usability test was conducted by 10 expert panelists. When each emulsion composition was applied, the state of the emulsion composition was judged to be smooth and glossy according to the following criteria. ◎: More than 8 out of 10 people answered that it was smooth and shiny. ○: 4 to 7 out of 10 people answered that it was smooth and shiny. ×: Three or fewer out of ten people answered that it was smooth and shiny.

[0036] (2) Skin condition when the emulsion composition was applied A practical usability test was conducted by 10 expert panelists, who evaluated the feel of each emulsion composition when applied according to the following criteria. ◎: Eight or more out of ten people answered that the product was smooth and non-sticky when spread on the skin, and that it had a high occlusive effect on the skin. Good: 4 to 7 out of 10 people answered that it was smooth and non-sticky when spread on the skin, and that it had a high occlusive effect on the skin. ×: Three or less out of ten people answered that the product was smooth and non-sticky when spread on the skin, and that it had a high occlusive effect on the skin.

[0037] (3) Storage stability The emulsion composition was left in a 50°C incubator and the state of the emulsion composition was observed and evaluated. ◎: Maintained a good emulsified state even after being left for more than two weeks. ◯: Maintained good emulsification even after being left for more than a week. ×: A good emulsified state was maintained for less than one week. [Example]

[0038] (Methods for preparing the emulsion compositions of Examples 1 to 6 and Comparative Examples 1 and 2 shown in Table 1) Purified water was added to the acrylates / C10-30 alkyl acrylate crosspolymer (Pemulen TR-2, Lubrizol Advanced Materials), preservatives phenoxyethanol (Yokkaichi Chemical Co., Ltd.), propanediol (Zemea Select, DuPont Tate & Lyle Bio Products), hydrogenated lysolecithin (NIKKOL Resinol LL-20, Nikko Chemicals Co., Ltd.), hydroxylated lecithin (NIKKOL Resinol SH50, Nikko Chemicals Co., Ltd.), and L-arginine (Ajinomoto Co., Inc.) shown in Table 1, and the mixture was thoroughly dispersed and heated to approximately 80°C. The oil phase ingredients, consisting of hydrogenated lecithin (NIKKOL Resinol S-10, Nikko Chemicals Co., Ltd.), candelilla wax (Refined Candelilla Wax MK-4, Yokoseki Oil & Fat Industries Co., Ltd.), microcrystalline wax (Multiwax W-835, Sonneborn), preservative Nicoguard 88 (Nikko Chemicals Co., Ltd.), and squalane (Kishimoto Tokushu Katanyu Kogyosho Co., Ltd.), were heated to approximately 80°C and dissolved, added to the aqueous phase, and emulsified using a homomixer. The mixture was then cooled to obtain each W / O emulsion composition.

[0039] [Table 1]

[0040] As is clear from Table 1, compositions containing 0.5 to 5.0 mass% of hydrogenated lecithin, hydrogenated lysolecithin, or hydroxylated lecithin relative to the total emulsion composition were evaluated as having a high emulsified state, but compositions containing less than 0.5 mass% or more than 5.0 mass% had poor emulsification and did not produce smooth, glossy compositions.

[0041] (Methods for preparing the emulsion compositions of Examples 7 to 13 and Comparative Examples 3 and 4) Purified water was added to the acrylates / C10-30 alkyl acrylate crosspolymer (Pemulen TR-2, Lubrizol Advanced Materials) shown in Table 2, phenoxyethanol (Yokkaichi Chemical Co., Ltd.) as a preservative, propanediol (Zemea Select, DuPont Tate & Lyle Bio Products), hydrogenated lysolecithin (NIKKOL Resinol LL-20, Nikko Chemicals Co., Ltd.), and L-arginine (Ajinomoto Co., Inc.), and the mixture was thoroughly dispersed and heated to approximately 80°C. The oil phase ingredients, consisting of hydrogenated lecithin (NIKKOL Resinol S-10, Nikko Chemicals Co., Ltd.), candelilla wax (refined candelilla wax MK-4, Yokoseki Oil & Fat Industries Co., Ltd.), preservative Nicoguard 88 (Nikko Chemicals Co., Ltd.), olive oil (Olive Oil RR, Mitto Oil Mills Co., Ltd.), jojoba oil (Jojoba Oil, Summit Oil Mills Co., Ltd.), horse oil (refined horse oil, Yokoseki Oil & Fat Industries Co., Ltd.), isopropyl myristate (IPM-R, Kokyu Alcohol Industries Co., Ltd.), octyldodecanol (Oitanol G-JP, BASF Japan Ltd.), and isostearic acid (Isostearic Acid EX, Kokyu Alcohol Industries Co., Ltd.), were heated and dissolved to approximately 80°C, added to the aqueous phase, and emulsified using a homomixer. The mixture was then cooled to obtain each W / O emulsion composition.

[0042] [Table 2]

[0043] (Methods for preparing the emulsion compositions of Examples 7 to 13 and Comparative Examples 3 and 4) As is clear from Table 2, in Examples 7 to 13 in which the water content in the present invention was within the range of 50 to 80 mass % relative to the total amount of the emulsion composition, the skin condition when the emulsion composition was applied to the skin, the state of the emulsion composition, and storage stability were all good. However, in Comparative Examples 3 and 4 in which the water content was low and the oil content was high, the emulsion composition spread poorly when applied to the skin and felt very sticky, resulting in problems with usability when applied.

[0044] Table 3 shows the evaluation of emulsion compositions prepared by the methods shown in Examples 7 to 13 and Comparative Examples 3 and 4, relative to the total solid oil content of the present invention. In Examples 14 to 17, where the total solid oil content of the present invention was within the range of 1 to 3 mass% of the total emulsion composition, the emulsion compositions were in very good condition. However, when the total solid oil content was low, as in Comparative Examples 5 and 6, the emulsion compositions became too soft and their storage stability deteriorated. Furthermore, when the total solid oil content was too high, as in Comparative Example 7, the emulsion compositions lost their smoothness and were in poor condition.

[0045] [Table 3]

[0046] (Method for preparing each emulsion composition of Examples 18 to 23) Acrylates / C10-30 alkyl acrylate crosspolymer (Pemulen TR-2, Lubrizol Advanced Materials), carboxyvinyl polymer (Hibiswako 104, Fujifilm Wako Pure Chemical Industries, Ltd.), xanthan gum (Nomcoat Z, Nisshin Oillio Group, Inc.), carboxymethylcellulose (CMC 1160, Daicel FineChem Corporation), sodium hyaluronate (Hyaluronic Acid FCH-200, Kikkoman Biochemifa Corporation), pullulan (Hayashibara Co., Ltd.), propanediol (Zemea Select, DuPont Tate & Lyle Bio Products), hydrogenated lysolecithin (NIKKOL Resinol LL-20, Nikko Chemicals Co., Ltd.), purified water, and L-arginine (Ajinomoto Co., Inc.) were mixed and dispersed thoroughly, followed by heating to approximately 80°C. The oil phase ingredients, consisting of hydrogenated lecithin (NIKKOL Resinol S-10, Nikko Chemicals Co., Ltd.), candelilla wax (Refined Candelilla Wax MK-4, Yokoseki Oil & Fat Industries Co., Ltd.), microcrystalline wax (Multiwax W-835, Sonneborn), and petrolatum (Chloratum V, Croda Japan Co., Ltd.), were heated and dissolved to approximately 80°C, added to the aqueous phase, and emulsified using a homomixer. The mixture was then cooled to obtain each W / O emulsion composition.

[0047] [Table 4]

[0048] As is clear from Table 4, excellent emulsion compositions can be obtained by using 0.1 to 1% by mass of acrylic acid / methacrylic acid alkyl ester copolymer, carboxyvinyl polymer, xanthan gum, or sodium hyaluronate as the water-soluble polymer used in the present invention. Furthermore, excellent emulsion compositions were also obtained by using carboxymethyl cellulose and pullulan. [Industrial Applicability]

[0049] The present invention provides an emulsion composition containing high amounts of hydrocarbons, oils and fats, fatty acids, higher alcohols, esters, and waxes, which is highly safe for the skin, has a good emulsified state, and exhibits excellent storage stability. This emulsion composition is also useful for skin with reduced moisture retention due to rough skin, and for patients with atopic dermatitis.

Claims

1. (A) an oily base selected from the group consisting of hydrocarbons, fats and oils, fatty acids, higher alcohols, esters, and waxes; (B) a surfactant selected from the group consisting of hydrogenated lecithin, hydrogenated lysolecithin, and hydroxide lecithin; (C) solid oil; (D) Water, and (E) Water-soluble polymer The emulsion composition is a W / O type emulsion composition, wherein the content of (A) oily base is 15 to less than 40% by mass, the content of (B) surfactant is 0.5 to 5% by mass, the content of (C) solid oil is 0.1 to 5% by mass, and the content of (D) water is 50 to 80% by mass, and the W / O type emulsion composition is emulsified only with the (B) surfactant, and has a natural origin index (including water) calculated in accordance with ISO 16128 of 90 or more.

2. The emulsion composition according to claim 1, characterized in that the content of the oily base (A) is 20 to 35% by mass.

3. 2. The emulsion composition according to claim 1, wherein the content of the surfactant (B) is 0.5 to 3.5% by mass.

4. 2. The emulsion composition according to claim 1, wherein the (C) solid oil is at least one selected from the group consisting of a hydrocarbon selected from ceresin, paraffin, and microcrystalline wax, a wax selected from candelilla wax, carnauba wax, and beeswax, and a saturated higher alcohol selected from cetanol, stearyl alcohol, and behenyl alcohol, and the content of the (C) solid oil is 0.5 to 3% by mass.

5. 2. The emulsion composition according to claim 1, wherein the content of the water (D) is 50 to 75% by mass.

6. 2. The emulsion composition according to claim 1, wherein the water-soluble polymer (E) is at least one polymer selected from the group consisting of cellulose-based polymers, vinyl-based polymers, acrylic acid-based polymers, microbial-derived polymers, and mucopolysaccharides.

7. The emulsion composition according to claim 1, wherein the natural origin index (including water) is 95 or more.

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