Patent Description:
Lipids called stratum corneum intercellular lipid are present in gaps defined between corneocytes constituting the stratum corneum, which is the outermost layer of skin. The lipid composition of stratum corneum intercellular lipid contains about <NUM>% of ceramides, the rest including cholesterols, cholesterol esters, fatty acids and the like. Of these, ceramides are deeply involved with rough skin and dry skin, and it is known that the conditions of stratum corneum can be improved by externally supplementing ceramides.

For this point of view, various cosmetic products containing ceramides were reported. Ceramides have a high crystallinity and a high melting point and are hence difficult to be stabilized in a preparation. Thus, reports were made on a technique involving mixing a ceramide, phospholipid, and a cationic surfactant (Patent Literature <NUM>), a technique involving adding a carboxylic acid and a base to ceramides to prepare an oil-in-water emulsion (Patent Literature <NUM>), and an emulsified composition in which sphingosines, a glycerol mono-fatty acid ester, and a higher alcohol are added to ceramides (Patent Literature <NUM>).

Patent Literature <NUM> describes a hair-treating agent containing (A) <NUM>-<NUM> wt. % of a specific iso type fatty acid cholesterol ester or a specific anti-iso type fatty acid cholesterol ester in a total amount of <NUM>-<NUM> wt. % based on the total amount of the final product and (B) at least one of a kind selected from sphingolipids (sphingoglucolipids such as glycosyl ceramide, and sphingophospholipids such as sphingomyelin) in an amount of <NUM>-<NUM> wt.

Patent Literature <NUM> concerns an anti-pro-oxidant glucosyl octyl ascorbic acid derivative.

Patent Literature <NUM> refers to an oil-in-water type emulsion cosmetic which contains (A) a hydrophilic surface active agent, (B) an oily component and (C) water, and weight ratio of the component (B) is <NUM> or more based on <NUM> of the component (A).

Patent Literature <NUM> describes an emulsion composition comprising the following ingredients (A), (B), (C), (D), (E), and (F): (A) glyceryl monofatty acid ester derived from a linear-chain fatty acid having <NUM> to <NUM> carbon atoms; (B) a higher alcohol having <NUM> to <NUM> carbon atoms; (C) a ceramide; (D) an anionic surfactant; (E) a polar oil selected from branched fatty acid esters having an IOB of from <NUM> to <NUM> and having a hydroxyl group or an amino group; and (F) water, wherein the mass ratio of the total content of ingredients (A), (B), and (C) and ingredient (D) in terms of acid to the content of ingredient (E), ((A)+(B)+(C)+(D))/(E), is from <NUM> to <NUM>.

The present invention provides an emulsified composition comprising (A) <NUM> mass% or more and <NUM> mass% or less of an anionic surfactant comprising one or more selected from the group consisting of N-acylamino acids, fatty acids having <NUM> to <NUM> carbon atoms, alkyl ether carboxylic acids, diacyl glutamic acid lysine, alkylsulfosuccinic acids, N-acyl methyl taurine, alkyl sulfates, polyoxyethylene alkyl ether sulfuric acids, polyoxyethylene alkyl ether phosphoric acids, and salts thereof, (B) a cationic surfactant comprising one or more selected from the group consisting of monoalkyl quaternary ammonium salts, dialkyl quaternary ammonium salts, diacylethyl hydroxyethylmonium methosulfates, and acyl arginine ethyl pyrrolidone carboxylic acid salts, (C) a ceramide, and (D) water, wherein the mass ratio of Component (A) to Component (B), A/B, is <NUM> or more and <NUM> or less.

Stable addition of highly crystalline ceramides requires a large amount of surfactants, which, however, causes stickiness. Additionally, conventional emulsified compositions form a hydrophilic film by a surfactant and consequently the film runs down by water or sweat, posing a problem of poor film persistency.

Accordingly, the present invention provides an emulsified composition which contains a ceramide stably, has a smooth feel of use and has a good persistency of an applied film.

Under the circumstances, the present inventors conducted studies to obtain an emulsified composition which contains a ceramide stably, has a favorable feel of use and has a good persistency of an applied film, and found that when an anionic surfactant and a cationic surfactant are used in combination to emulsify an oil phase containing a ceramide with an aqueous phase, an emulsified composition can be obtained which provides a hydrophobic applied film to thereby bring about a smooth and firm feel of use, the applied film also having good persistency. Thus the present invention were accomplished.

The emulsified composition of the present invention contains a ceramide stably and provides an applied film with a smooth and firm feel, the applied film also having good persistency.

The emulsified composition of the present invention contains (A) <NUM> mass% or more and <NUM> mass% or less of an anionic surfactant comprising one or more selected from the group consisting of N-acylamino acids, fatty acids having <NUM> to <NUM> carbon atoms, alkyl ether carboxylic acids, diacyl glutamic acid lysine, alkylsulfosuccinic acids, N-acyl methyl taurine, alkyl sulfates, polyoxyethylene alkyl ether sulfuric acids, polyoxyethylene alkyl ether phosphoric acids, and salts thereof, (B) a cationic surfactant comprising one or more selected from the group consisting of monoalkyl quaternary ammonium salts, dialkyl quaternary ammonium salts, diacylethyl hydroxyethylmonium methosulfates, and acyl arginine ethyl pyrrolidone carboxylic acid salts, (C) a ceramide, and (D) water, wherein the mass ratio of Component (A) to Component (B), A/B, is <NUM> or more and <NUM> or less.

The anionic surfactant (A) contains one or more selected from the group consisting of carboxylic acid salt type such as N-acylamino acids, fatty acids having <NUM> to <NUM> carbon atoms, alkyl ether carboxylic acids, polyoxyethylene alkyl ether carboxylic acids, acyl lactic acids, N-acyl methylalanine, N-acyl sarcosine, diacyl amino acids, and salts thereof, sulfonic acid salt type such as alkanesulfonic acids, α-olefin sulfonic acids, α-sulfo fatty acid methyl esters, acyl isethionic acids, alkylsulfosuccinic acids, N-acyl methyl taurine, and salts thereof, sulfuric acid salt type such as alkyl sulfates, polyoxyethylene alkyl sulfates, alkyl ether sulfuric acids, polyoxyethylene alkyl ether sulfuric acids, fatty acid alkanolamide sulfates, and salts thereof, phosphoric acid salt type such as alkyl phosphates, polyoxyethylene alkyl ether phosphoric acids, and salts thereof. In view of improving a smooth and firm feel and the persistency of an applied film, the anionic surfactant (A) preferably contains one or more selected from the group consisting of N-acylamino acids, fatty acids, alkyl ether carboxylic acids, diacyl glutamic acid lysine, alkylsulfosuccinic acids, N-acyl methyl taurine, alkyl sulfates, polyoxyethylene alkyl sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphoric acids, and salts thereof.

Of these, the anionic surfactant (A) preferably contains one or more selected from the group consisting of N-acylamino acids, fatty acids having <NUM> to <NUM> carbon atoms, alkyl ether carboxylic acids, diacyl glutamic acid lysine, alkylsulfosuccinic acids, N-acyl methyl taurine, alkyl sulfates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl ether phosphoric acids, and salts thereof.

Further, the anionic surfactant (A) more preferably contains one or more selected from the group consisting of N-acylamino acids, fatty acids having <NUM> to <NUM> carbon atoms, alkyl ether carboxylic acids, diacyl glutamic acid lysine, alkylsulfosuccinic acids, N-acyl methyl taurine, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl ether phosphoric aids, and salts thereof.

Additionally, the anionic surfactant (A) further preferably contains one or more selected from the group consisting of N-acylamino acids, fatty acids having <NUM> to <NUM> carbon atoms, diacyl glutamic acid lysine, N-acyl methyl taurine, polyoxyethylene alkyl ether phosphoric acids, and salts thereof, and furthermore preferably contains N-acylamino acids and salts thereof.

Examples of N-acylamino acids and salts thereof include N-acylglutamic acids such as N-lauroyl-L-glutamic acid, N-stearoyl-L-glutamic acid, N-myristoyl-L-glutamic acid, and salts thereof.

Examples of fatty acids having <NUM> to <NUM> carbon atoms include fatty acids such as lauric acid, palmitic acid, stearic acid, and salts thereof.

Examples of alkyl ether carboxylic acids and salts thereof include polyoxyethylene lauryl ether acetic acid and salts thereof.

Examples of diacyl glutamic acid lysine and salts thereof include dilauramidoglutamide lysine and salts thereof.

Examples of alkylsulfosuccinic acids and salts thereof include di-<NUM>-ethylhexyl sulfosuccinic acid and salts thereof.

Examples of N-acyl methyl taurine and a salt thereof include N-myristoyl-N-methyl taurine, N-lauroyl-N-methyl taurine, N-stearoyl-N-methyl taurine, and salts thereof.

Examples of alkyl sulfates and salts thereof include lauryl sulfate and salts thereof.

Examples of polyoxyethylene alkyl sulfates and salts thereof include polyoxyethylene lauryl sulfate and salts thereof.

Examples of alkyl phosphoric acids and salts thereof include monomyristyl phosphoric acid, monostearyl phosphoric acid, di(C12-<NUM>)pareth-<NUM> phosphoric acids, and salts thereof.

Examples of polyoxyethylene alkyl phosphoric acids and salts thereof include polyoxyethylene oleyl ether phosphoric acid, polyoxyethylene cetyl ether phosphoric acid, polyoxyethylene stearyl ether phosphoric acid, and salts thereof.

Examples of the salt structure making up these salts include salts of alkali metal such as sodium and potassium, salts of basic amino acid such as L-arginine, L-histidine, and L-lysine, and alkanolamine salts such as triethanolamine. These anionic surfactants can be used singly or in combination of two or more thereof.

The content of Component (A) in the emulsified composition of the present invention is, in view of formability of a hydrophobic applied film and obtaining a smooth and firm feel and in view of improving the persistency of an applied film, <NUM> mass% or more, preferably <NUM> mass% or more, more preferably <NUM> mass% or more, and furthermore preferably <NUM> mass% or more, and <NUM> mass% or less, preferably <NUM> mass% or less, more preferably <NUM> mass% or less, and furthermore preferably <NUM> mass% or less. Specifically, the content of Component (A) is <NUM> mass% or more and <NUM> mass% or less, preferably <NUM> mass% or more and <NUM> mass% or less, more preferably <NUM> mass% or more and <NUM> mass% or less, and furthermore preferably <NUM> mass% or more and <NUM> mass% or less.

The cationic surfactant (B) contains one or more selected from the group consisting of those of aliphatic amine salt type, quaternary ammonium salt type, and DL-pyrrolidone carboxylic acid salt type, and, in view of improving a smooth and firm feel and improving the persistency of an applied film, the cationic surfactant (B) preferably contains quaternary ammonium salt and an acyl arginine ethyl pyrrolidone carboxylic acid salt.

Of these, the cationic surfactant (B) preferably contains one or more selected from the group consisting of monoalkyl quaternary ammonium salts, dialkyl quaternary ammonium salts, and acyl arginine ethyl pyrrolidone carboxylic acid salts.

Further, the cationic surfactant (B) further preferably contains one or more selected from the group consisting of mono C12-C24 alkyltrimethylammonium salts, di C12-C24 alkyldimethylammonium salts, diacylethyl hydroxyethylmonium methosulfates, and acyl arginine ethyl pyrrolidone carboxylic acid salts.

Examples of mono C12-C24 alkyltrimethylammonium salts include lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, and behenyl trimethyl ammonium chloride.

Examples of di C12-C24 alkyldimethylammonium salts include dilauryldimethylammonium chloride, distearyldimethylammonium chloride, dibehenyldimethylammonium chloride.

Examples of diacylethyl hydroxyethylmonium methosulfates include dicocoylethyl hydroxyethylmonium methosulfate.

Examples of acyl arginine ethyl pyrrolidone carboxylic acid salts include cocoyl arginine ethyl pyrrolidone carboxylic acid salts.

These cationic surfactants can be used singly, or in combination of two or more thereof.

The content of Component (B) in the emulsified composition of the present invention is, in view of formability of a hydrophobic applied film and obtaining a smooth and firm feel and in view of improving the persistency of an applied film, preferably <NUM> mass% or more, more preferably <NUM> mass% or more, further preferably <NUM> mass% or more, and furthermore preferably <NUM> mass% or more, and preferably <NUM> mass% or less, more preferably <NUM> mass% or less, further preferably <NUM> mass% or less, furthermore preferably <NUM> mass% or less, and furthermore preferably <NUM> mass% or less. Specifically, the content of Component (B) is preferably <NUM> mass% or more and <NUM> mass% or less, more preferably <NUM> mass% or more and <NUM> mass% or less, further preferably <NUM> mass% or more and <NUM> mass% or less, furthermore preferably <NUM> mass% or more and <NUM> mass% or less, and furthermore preferably <NUM> mass% or more and <NUM> mass% or less.

Additionally, in the emulsified composition of the present invention, the mass ratio of Component (A) to Component (B), A/B, is, in view of formability of a hydrophobic applied film and obtaining a smooth and firm feel and in view of improving the persistency of an applied film, <NUM> or more, preferably <NUM> or more, more preferably <NUM> or more, further preferably <NUM> or more, and furthermore preferably <NUM> or more, and <NUM> or less, preferably <NUM> or less, more preferably <NUM> or less, further preferably <NUM> or less, and furthermore preferably <NUM> or less. Specifically, the mass ratio A/B is <NUM> or more and <NUM> or less, preferably <NUM> or more and <NUM> or less, more preferably <NUM> or more and <NUM> or less, further preferably <NUM> or more and <NUM> or less, and furthermore preferably <NUM> or more and <NUM> or less.

The ceramide (C) may be either a natural ceramide or a pseudo-ceramide, and preferably contains one or more selected from the group consisting of those represented by the following Formula (<NUM>) or (<NUM>).

Examples include compounds wherein R<NUM> is a linear alkyl group having preferably <NUM> to <NUM> carbon atoms, and further preferably <NUM> to <NUM> carbon atoms; and R<NUM> is a linear alkyl group having <NUM> to <NUM> carbon atoms and optionally substituted with a hydroxyl group or a linear alkyl group having <NUM> to <NUM> carbon atoms to which linoleic acid is ester-bonded. Additionally, X<NUM> preferably represents a hydrogen atom or forms an oxo group together with an oxygen atom. Particularly, R<NUM> is preferably trichosyl, <NUM>-hydroxypentadecyl, <NUM>-hydroxytrichosyl, heptadecyl, <NUM>-hydroxyundecyl, a nonacosyl group in which linoleic acid is ester-bonded at the ω terminus.

The natural ceramide is preferably one or more selected from the group consisting of ceramides of types <NUM> to <NUM>, which are amidated sphingosine, dihydrosphingosine, phytosphingosine and sphingadienine (for example, swine and human ceramides described in Figure <NUM> of <NPL>) and Figure <NUM> of <NPL>).

N-Alkyl forms (for example, N-methyl form) of these ceramides are further included.

For these ceramides, a natural form (D(-) form) optically active substance may be used, a non-natural form (L(+) form) optically active substance may be used, and a mixture of natural and non-natural forms may be used. Relative configuration of the above compounds may be a natural form configuration, other non-natural form configurations, or a mixture thereof. Of these, one or more selected from the group consisting of compounds CERAMIDE1, CERAMIDE2, CERAMIDE3, CERAMIDE5 and CERAMIDE6II (all in INCI, 8th Edition) and those represented by the following formula are preferable.

These may be a natural extract or a synthetic product, and a commercial product can be used.

When a commercial natural form ceramide is used, one or more selected from the group consisting of Ceramide I, Ceramide III, Ceramide IIIA, Ceramide IIIB, Ceramide IIIC, Ceramide VI (all from COSMO FARM), Ceramide TIC-<NUM> (TAKASAGO INTERNATIONAL CORPORATION), CERAMIDE II (Quest International), DS-Ceramide VI, DS-CLA-Phytoceramide, C6-Phytoceramide, DS-ceramide Y3S (Doosan Corporation), and CERAMIDE2 (Sederma) are preferable. <CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

<CHM>
wherein R<NUM> represents a saturated or unsaturated linear, branched or cyclic hydrocarbon group having <NUM> to <NUM> carbon atoms and optionally substituted with a hydroxyl group, or a hydrogen atom; X<NUM> represents a hydrogen atom, an acetyl group, or a glyceryl group; R<NUM> is a saturated or unsaturated linear, branched or cyclic hydrocarbon group having <NUM> to <NUM> carbon atoms and optionally substituted with a hydroxyl group or an amino group, or represents a group wherein a saturated or unsaturated linear or branched chain fatty acid having <NUM> to <NUM> carbon atoms and optionally substituted with a hydroxyl group is ester-bonded at the ω terminus of the hydrocarbon group; and R<NUM> represents a hydrogen atom, or represents an alkyl group having the total carbon atom of <NUM> to <NUM> and optionally substituted with a hydroxyl group, a hydroxyalkoxy group, an alkoxy group, or an acetoxy group.

R<NUM> is particularly preferably nonyl, tridecyl, pentadecyl, an undecyl group in which linoleic acid is ester-bonded at the ω-position, a pentadecyl group in which linoleic acid is ester-bonded at the ω-position, a pentadecyl group in which <NUM>-hydroxystearic acid is ester-bonded at the ω-position, or an undecyl group in which methyl-branched isostearic acid is amide-bonded at the ω-position.

When R<NUM> is a hydrogen atom, R<NUM> is preferably an alkyl group having the total carbon atom of <NUM> to <NUM>, preferably the total carbon atom of <NUM> to <NUM>, in which a hydroxyl group, a hydroxyalkoxy group, an alkoxy group, or an acetoxy group is optionally substituted, and when R<NUM> is a saturated or unsaturated linear, branched or cyclic hydrocarbon group having <NUM> to <NUM> carbon atoms and optionally substituted with a hydroxyl group, R<NUM> preferably represents a hydrogen atom, or an alkyl group having the total carbon atom of <NUM> to <NUM> and optionally substituted with a hydroxyl group, a hydroxyalkoxy group, an alkoxy group, or an acetoxy group. The hydroxyalkoxy group or the alkoxy group of R<NUM> preferably has <NUM> to <NUM> carbon atoms. <CHM>
<CHM>.

Formula (<NUM>) is preferably at least one selected from the group consisting of pseudo-ceramides wherein R<NUM> is a hexadecyl group, X<NUM> is an hydrogen atom, R<NUM> is a pentadecyl group, and R<NUM> is a hydroxyethyl group; and those wherein R<NUM> is a hexadecyl group, X<NUM> is a hydrogen atom, R<NUM> is a nonyl group, and R<NUM> is a hydroxyethyl group, and further preferably those of Formula (<NUM>) wherein R<NUM> is a hexadecyl group, X<NUM> is a hydrogen atom, R<NUM> is a pentadecyl group, R<NUM> is a hydroxyethyl group (N-(hexadecyloxyhydroxypropyl)-N-hydroxyethylhexadecanamide. <CHM>
<CHM>.

The content of Component (C) in the emulsified composition of the present invention is, in view of obtaining a moisturizing effect and a smooth and firm feel and in view of improving the persistency of an applied film, preferably <NUM> mass% or more, more preferably <NUM> mass% or more, further preferably <NUM> mass% or more, furthermore preferably <NUM> mass% or more, furthermore preferably <NUM> mass% or more, and furthermore preferably <NUM> mass% or more, and preferably <NUM> mass% or less, more preferably <NUM> mass% or less, further preferably <NUM> mass% or less, and furthermore preferably <NUM> mass% or less. Specifically, the content of Component (C) is preferably <NUM> mass% or more and <NUM> mass% or less, more preferably <NUM> mass% or more and <NUM> mass% or less, further preferably <NUM> mass% or more and <NUM> mass% or less, furthermore preferably <NUM> mass% or more and <NUM> mass% or less, furthermore preferably <NUM> mass% or more and <NUM> mass% or less, and furthermore preferably <NUM> mass% or more and <NUM> mass% or less.

Additionally, in view of formability of a hydrophobic applied film and obtaining a smooth and firm feel and in view of improving the persistency of an applied film, the mass ratio of the total amount of Component (A) and Component (B) to the amount of Component (C), (A+B)/C, in the emulsified composition of the present invention is preferably <NUM> or more, more preferably <NUM> or more, further preferably <NUM> or more, furthermore preferably <NUM> or more, and furthermore preferably <NUM> or more, and preferably <NUM> or less, more preferably <NUM> or less, further preferably <NUM> or less, furthermore preferably <NUM> or less, and furthermore preferably <NUM> or less. Specifically, it is preferably <NUM> or more and <NUM> or less, more preferably <NUM> or more and <NUM> or less, further preferably <NUM> or more and <NUM> or less, furthermore preferably <NUM> or more and <NUM> or less, and furthermore preferably <NUM> or more and <NUM> or less.

The content of (D) water in the emulsified composition of the present invention is, in view of obtaining a smooth and firm feel and in view of improving the persistency of an applied film, preferably <NUM> mass% or more and <NUM> mass% or less, and more preferably <NUM> mass% or more and <NUM> mass% or less.

The emulsified composition of the present invention preferably contains (E) one or more selected from the group consisting of cholesterol and cholesterol fatty acid esters in addition to the above Components in view of stably incorporating the ceramide (C) thereinto, formability of a hydrophobic applied film, obtaining a smooth and firm feel, and improving the persistency of an applied film.

The cholesterol fatty acid ester is preferably a cholesterol ester with a fatty acid having <NUM> to <NUM> carbon atoms. More specifically, it is preferable to be one or more selected from the group consisting of cholesteryl laurate, cholesteryl palmitate, cholesteryl myristate, cholesteryl oleate, cholesteryl isostearate, and cholesteryl linoleate.

The content of Component (E) in the emulsified composition is, in view of formability of a hydrophobic applied film, a smooth and firm feel, and improving the persistency of an applied film, preferably <NUM> mass% or more and <NUM> mass% or less, more preferably <NUM> mass% or more and <NUM> mass% or less, further preferably <NUM> mass% or more and <NUM> mass% or less, and furthermore preferably <NUM> mass% or more and <NUM> mass% or less.

The emulsified composition of the present invention can further contain (F) a base and/or (G) an acid in addition to Components (A) and (B) to adjust the pH.

The base (F) is not particularly limited and may be an organic base or an inorganic base.

The organic base is preferably one or more selected from the group consisting of basic amino acids and alkanolamines. Specifically, it is preferable to be one or more selected from the group consisting of basic amino acids such as L-arginine, lysine, and histidine; and alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, aminomethyl propanol, aminomethyl propanediol, aminoethyl propanediol and trishydroxymethylaminoethane.

The inorganic base is preferably one or more selected from the group consisting of calcium hydroxide, sodium hydroxide, and potassium hydroxide.

Of these, the base is preferably one or more selected from the group consisting of L-arginine, calcium hydroxide, sodium hydroxide, and potassium hydroxide.

These for the base (F) can be used singly or in combination of two or more thereof, and is contained in an amount of preferably from <NUM> to <NUM> mass%, and more preferably from <NUM> to <NUM> mass%, in the whole composition in view of achieving a further favorable feel of use.

Additionally, the acid (G) may be an organic acid or an inorganic acid.

The organic acid is preferably one or more selected from the group consisting of monocarboxylic acids, dicarboxylic acids, oxycarboxylic acids, and acidic amino acids. Specifically, it is preferably one or more selected from the group consisting of monocarboxylic acids such as acetic acid, propionic acid, and butyric acid; dicarboxylic acids such as succinic acid, phthalic acid, fumaric acid, oxalic acid, malonic acid, glutaric acid, and adipic acids; oxycarboxylic acids such as glycolic acid, citric acid, lactic acid, pyruvic acid, malic acid, and tartaric acid; and acidic amino acids such as glutamic acid, and aspartic acid.

The inorganic acid is preferably one or more selected from the group consisting of hydrochloric acid, nitric acid, nitrous acid, sulfuric acid, sulfurous acid, phosphoric acid, phosphonic acid, and phosphinic acid.

Of these, the acid is preferably one or more selected from the group consisting of acidic amino acids and phosphoric acid.

One or more of these can be used as the acid (G), and the acid (G) is preferably contained in an amount of from <NUM> to <NUM> mass%, and more preferably from <NUM> to <NUM> mass%, based on the whole composition.

According to the present invention, the effects of the present invention, which are the formation of a hydrophobic applied film, a smooth and firm feel of use and the persistency of such a film, can be obtained in wide pH ranges (pH <NUM> to <NUM>).

The emulsified composition of the present invention can be produced, for example, by heating and mixing an oil phase containing Components (A) to (C) at from <NUM> to <NUM>, adding an aqueous phase component(s) thereto and stirring the resulting mixture to homogeneously emulsify.

The method for producing the emulsified composition of the present invention specifically includes Step <NUM> of heating and mixing an oil phase containing Components (A) to (C), and Step <NUM> of mixing an aqueous phase containing Component (D) with the oil phase and stirring the resultant. Further, the method preferably includes, between Step <NUM> and Step <NUM>, Step <NUM> of dissolving Component (F) or Component (G) in a part of Component (D) to obtain an aqueous solution and adding the aqueous solution to the oil phase to obtain a mixture, and Step <NUM> of cooling the mixture after Step <NUM>. Additionally, the production method can include, after Step <NUM>, Step <NUM>-<NUM> of dissolving Component (F) or Component (G) in a part of Component (D) to obtain an aqueous solution and adding the aqueous solution to the composition to obtain a mixture. In these cases, the content of Component (D) is the total amount of the amounts added at each Step. Additionally, in the step of heating and mixing, the heating temperature is preferably at the highest melting point of the melting points of the components to be mixed or more and <NUM> or less.

The method for producing the emulsified composition of the present invention preferably includes Step <NUM> of heating and mixing an oil phase containing Components (A) to (C), and preferably Component (E), Step <NUM> of dissolving Component (F) or Component (G) in a part of Component (D) to obtain an aqueous solution and adding the aqueous solution to the oil phase to obtain a mixture, Step <NUM> of cooling the mixture after Step <NUM>, and Step <NUM> of further mixing an aqueous phase containing remaining of Component (D) with the oil phase and stirring the resultant.

The emulsified composition of the present invention can use a commercial homomixer, dispermixer, ultramixer, high pressure homogenizer, or micromixer but the high pressure homogenizer and the micromixer can be used as a means for further micronization.

The emulsification method using the high pressure homogenizer or the micromixer is preferable in view of uniformalizing particle sizes of emulsified particles, improving storage stability, and the expectation in improved permeability of micronized ceramides to the skin, and can produce a micronized emulsion having a particle size of dispersed particles (volume average particle size) of <NUM> or less, preferably <NUM> or less, and more preferably <NUM> or less.

The emulsified composition of the present invention has a vesicle formed and the vesicle structure is stable. Additionally, when the emulsified composition of the present invention is applied to the skin, a highly hydrophobic applied film is formed. The formation of such a highly hydrophobic applied film provides a high moisturizing function and also a smooth and firm feel. Further, a highly hydrophobic applied film shows strong water resistance thus making a favorable feel of use last.

The emulsified composition of the present invention is applicable as an external preparation for the skin such as cosmetic products. In the case of a cosmetic product, the composition can further contain, in addition to the above components, components typically used for cosmetic products such as an oil component other than above, a lower alcohol, a moisturizer, an antioxidant, a preservative, a chelating agent, a whitening agent, a UV absorber, vitamins, a plant extract, other various medicinal components, a powder, a perfume, and a coloring material.

With reference to embodiments described above, the present invention further discloses the following composition.

An emulsified composition comprising (A) <NUM> mass% or more and <NUM> mass% or less of an anionic surfactant comprising one or more selected from the group consisting of N-acylamino acids, fatty acids having <NUM> to <NUM> carbon atoms, alkyl ether carboxylic acids, diacyl glutamic acid lysine, alkylsulfosuccinic acids, N-acyl methyl taurine, alkyl sulfates, polyoxyethylene alkyl ether sulfuric acids, polyoxyethylene alkyl ether phosphoric acids, and salts thereof, (B) a cationic surfactant comprising one or more selected from the group consisting of monoalkyl quaternary ammonium salts, dialkyl quaternary ammonium salts, diacylethyl hydroxyethylmonium methosulfates, and acyl arginine ethyl pyrrolidone carboxylic acid salts, (C) a ceramide, and (D) water, wherein the mass ratio of Component (A) to Component (B), A/B, is <NUM> or more and <NUM> or less.

The anionic surfactant (A) may comprise one or more selected from the group consisting of N-acylamino acids, fatty acids having <NUM> to <NUM> carbon atoms, diacyl glutamic acid lysine, N-acyl methyl taurine, polyoxyethylene alkyl ether phosphoric acids, and salts thereof.

The anionic surfactant (A) may comprise one or more selected from the group consisting of N-acylamino acids and salts thereof.

The content of Component (A) is preferably <NUM> mass% or more, further preferably <NUM> mass% or more, and furthermore preferably <NUM> mass% or more, and preferably <NUM> mass% or less, further preferably <NUM> mass% or less, and furthermore preferably <NUM> mass% or less, and preferably <NUM> mass% or more and <NUM> mass% or less, further preferably <NUM> mass% or more and <NUM> mass% or less, and furthermore preferably <NUM> mass% or more and <NUM> mass% or less.

The cationic surfactant (B) may comprise one or more selected from the group consisting of mono C12-C24 alkyltrimethylammonium salts, di C12-C24 alkyldimethylammonium salts, diacylethyl hydroxyethylmonium methosulfates, and acyl arginine ethyl pyrrolidone carboxylic acid salts.

The content of Component (B) is preferably <NUM> mass% or more, more preferably <NUM> mass% or more, further preferably <NUM> mass% or more, and furthermore preferably <NUM> mass% or more, and preferably <NUM> mass% or less, more preferably <NUM> mass% or less, further preferably <NUM> mass% or less, furthermore preferably <NUM> mass% or less, and furthermore preferably <NUM> mass% or less, and preferably <NUM> mass% or more and <NUM> mass% or less, more preferably <NUM> mass% or more and <NUM> mass% or less, further preferably <NUM> mass% or more and <NUM> mass% or less, furthermore preferably <NUM> mass% or more and <NUM> mass% or less, and furthermore preferably <NUM> mass% or more and <NUM> mass% or less.

The ceramide (C) may comprise one or more selected from the group consisting of natural ceramides and pseudo-ceramides.

The content of Component (C) is preferably <NUM> mass% or more, more preferably <NUM> mass% or more, further preferably <NUM> mass% or more, furthermore preferably <NUM> mass% or more, furthermore preferably <NUM> mass% or more, and furthermore preferably <NUM> mass% or more, and preferably <NUM> mass% or less, more preferably <NUM> mass% or less, further preferably <NUM> mass% or less, furthermore preferably <NUM> mass% or less, and preferably <NUM> mass% or more and <NUM> mass% or less, more preferably <NUM> mass% or more and <NUM> mass% or less, further preferably <NUM> mass% or more and <NUM> mass% or less, furthermore preferably <NUM> mass% or more and <NUM> mass% or less, furthermore preferably <NUM> mass% or more and <NUM> mass% or less, and furthermore preferably <NUM> mass% or more and <NUM> mass% or less.

The mass ratio of Component (A) to Component (B), A/B, is preferably <NUM> or more, more preferably <NUM> or more, further preferably <NUM> or more, and preferably <NUM> or less, more preferably <NUM> or less, further preferably <NUM> or less, furthermore preferably <NUM> or less, and preferably <NUM> or more and <NUM> or less, more preferably <NUM> or more and <NUM> or less, further preferably <NUM> or more and <NUM> or less, and furthermore preferably <NUM> or more and <NUM> or less.

The mass ratio of the total amount of Component (A) and Component (B) to the amount of Component (C), (A+B)/C, is preferably <NUM> or more, more preferably <NUM> or more, further preferably <NUM> or more, furthermore preferably <NUM> or more, furthermore preferably <NUM> or more, and preferably <NUM> or less, more preferably <NUM> or less, further preferably <NUM> or less, further preferably <NUM> or less, and furthermore preferably <NUM> or less, and preferably <NUM> or more and <NUM> or less, more preferably <NUM> or more and <NUM> or less, further preferably <NUM> or more and <NUM> or less, furthermore preferably <NUM> or more and <NUM> or less, and furthermore preferably <NUM> or more and <NUM> or less.

The the content of Component (D) is preferably <NUM> mass% or more and <NUM> mass% or less, and more preferably <NUM> mass% or more and <NUM> mass% or less.

The emulsified composition may further comprise (E) one or more selected from the group consisting of cholesterol and fatty acid cholesterol esters.

The emulsified composition may further comprise (F) a base and/or (G) an acid.

The emulsified composition may be a cosmetic product.

A method for producing the emulsified composition, comprising Step <NUM> of heating and mixing an oil phase comprising Components (A) to (C), Step <NUM> of dissolving the base as Component (F) or the acid as Component (G) in a part of water as Component (D) to obtain an aqueous solution and adding the aqueous solution to the oil phase to obtain a mixture, Step <NUM> of cooling the mixture after Step <NUM>, and Step <NUM> of mixing an aqueous phase comprising remaining of Component (D) with the oil phase and stirring the resultant.

The oil phase in Step <NUM> may further comprise (E) one or more selected from the group consisting of cholesterol and fatty acid cholesterol esters, and the oil phase comprising Components (A) to (C) and Component (E) may be heated and mixed in Step <NUM>.

The present invention is further described with reference to examples.

Components (A), (B), (C), and (E) were mixed, dissolved by heating at from <NUM> to <NUM> and stirred. Further, an aqueous solution in which (G) phosphoric acid or (F) L-arginine had been dissolved in a part (<NUM> mass%) of water was added thereto, and the resultant was homogenized, and subsequently cooled to <NUM> while stirring. Then, remaining components were mixed therewith and homogenized by stirring.

Condition of the emulsified particles was observed immediately after a sample was prepared for the presence or absence of particles and Maltese cross using a microscope (under direct light and polarized light). Samples in which particles and Maltese cross were observed ranked as "A", samples in which a multilayer lamellar structure of particles was observed ranked as "B", and samples in which no particle was observed ranked as "C".

Panelists (N=<NUM>) specialized in cosmetic product evaluation applied a proper amount (<NUM>) of a sample on back of the hand and evaluated (total <NUM> points) on a feel (smooth and firm feel) by criteria with <NUM> ratings (<NUM> points: Good, <NUM> points: Rather good, <NUM> points: Rather not good, <NUM> point: Not good). Total points are shown in the table.

A proper amount (<NUM>) of a sample was applied on back of the hand to form a dry applied film on the skin, subsequently the hand was washed with water, and then a feel (smooth and firm feel) was examined. Cases in which the feel persisted ranked as "A", cases in which the feel rather persisted ranked as "B", and cases in which the feel did not persist ranked as "C".

<NUM> of a sample was applied to on per area of <NUM> x <NUM> of an artificial leather and dried, and subsequently reapplication was repeatedly carried out <NUM> times. After drying for <NUM> hours, <NUM>µL of a water droplet was dropped on the applied film under environment at <NUM> and contact angles immediately after dropping and <NUM> seconds after dropping were measured using an automatic contact angle meter DM-501H1 (manufactured by Kyowa Interface Science Co. /Kitahama factory).

Contact angles immediately after dropping and <NUM> seconds after dropping greater than <NUM>° were defined as hydrophobic, whereas those smaller than <NUM>° were defined as hydrophilic.

Comparison was made between a case in which an anionic surfactant and a cationic surfactant were used together with a ceramide and a case in which an anionic surfactant or a cationic surfactant was singly used with a ceramide. The results revealed that, when an anionic surfactant and a cationic surfactant were used together, a hydrophobic applied film was formed, a smooth and firm feel of use was obtained, and the film persisted, as evident in Table <NUM>.

Contents of the anionic surfactant and the cationic surfactant were changed and the evaluations described above were carried out. The results reveal that the effects of the present invention, which are the formation of a hydrophobic applied film, a smooth and firm feel of use and the persistency of the film, were obtained regardless of these contents, but when A/B is <NUM> or more and <NUM> or less, the evaluation results are favorable.

The evaluations described above were carried out using various anionic surfactants and cationic surfactants. The results revealed that the effects of the present invention, which are the formation of a hydrophobic applied film, a smooth and firm feel of use and the persistency of the film, were obtained regardless of the type of anionic surfactants and cationic surfactants, as evident in Table <NUM>.

The emulsified compositions having the compositions of Table <NUM> were obtained and the evaluations described above were carried out. The results revealed that the effects of the present invention, which are the formation of a hydrophobic applied film, a smooth and firm feel of use and the persistency of the film, were obtained regardless of the ceramide content, as evident in Table <NUM>. Additionally, it was revealed that the effects of the present invention, which are the formation of a hydrophobic applied film, a smooth and firm feel of use and the persistency of the film, were obtained in wide pH ranges regardless of pH.

The emulsified compositions having the compositions of Table <NUM> were obtained and the evaluations described above were carried out. The results revealed that the emulsified composition of Comparative Example <NUM>, in which the mass ratio of Component (A) to Component (B), A/B, exceeded <NUM>, failed to form a hydrophobic applied film and the film had poor persistency, as evident in Table <NUM>.

Claim 1:
An emulsified composition comprising (A) <NUM> mass% or more and <NUM> mass% or less of an anionic surfactant comprising one or more selected from the group consisting of N-acylamino acids, fatty acids having <NUM> to <NUM> carbon atoms, alkyl ether carboxylic acids, diacyl glutamic acid lysine, alkylsulfosuccinic acids, N-acyl methyl taurine, alkyl sulfates, polyoxyethylene alkyl ether sulfuric acids, polyoxyethylene alkyl ether phosphoric acids, and salts thereof, (B) a cationic surfactant comprising one or more selected from the group consisting of monoalkyl quaternary ammonium salts, dialkyl quaternary ammonium salts, diacylethyl hydroxyethylmonium methosulfates, and acyl arginine ethyl pyrrolidone carboxylic acid salts, (C) a ceramide, and (D) water, wherein the mass ratio of Component (A) to Component (B), A/B, is <NUM> or more and <NUM> or less.