Skin cleansing composition

Abstract

To provide a skin cleansing composition that ensures sufficient foaming during cleansing and allows moisturized sensation after cleansing.SOLUTION: A skin cleansing composition comprises the following components (A) and (B). The mass ratio (B / A) of component (B) to component (A) is 0.5 or more and less than 4. Component (A) is an anionic surfactant containing a higher fatty acid or a salt thereof. Component (B) is a particle containing a water-holding oil agent, a humectant, and a polymer.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a skin cleansing composition.

Background Art

[0002] The main purpose of skin cleansers is to wash away dirt such as sebum, sweat, and dust on the skin. However, many consumers feel anxious that their skin will become dry when using cleansers for face washing or full-body washing. For this reason, skin cleansers that maintain a moisturizing effect even after washing have been studied.

[0003] The present applicant has found and reported that a skin cleansing agent containing particles containing a water-retaining oil agent, a moisturizing agent, and a polymer, and a surfactant is excellent in detergency and rinsability, has no squeaky feeling or tight feeling even after washing, is moist, and provides a soft skin feel (Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the skin cleansing agent described in Patent Document 2, although excellent detergency and a moist feeling after washing can be obtained, the foaming during washing is not sufficient. Therefore, an object of the present invention is to provide a skin cleansing composition that has sufficient foaming during washing and provides a moist feeling after washing.

Means for Solving the Problems

[0006] Therefore, the present inventors have completed the present invention by formulating an anionic surfactant containing a higher fatty acid or its salt, which was not used in Patent Document 2, and particles containing a water-retaining oil agent, a humectant, and a polymer in a specific ratio, thereby achieving both excellent foaming property and moist feeling, which could not be obtained by formulating other surfactants.

[0007] That is, the present invention provides a skin cleansing composition containing the following components (A) and (B), wherein the mass ratio (B / A) of component (B) to component (A) is 0.5 or more and less than 4. (A) An anionic surfactant containing a higher fatty acid or its salt (B) Particles containing a water-retaining oil agent, a humectant, and a polymer Further, the present invention provides a method for cleansing the skin, which is characterized in that after applying the skin cleansing composition to the skin, it is rinsed with water.

Advantages of the Invention

[0008] The skin cleansing composition of the present invention is excellent in foaming during cleansing, excellent in detergency during cleansing, and imparts a moist feeling to the skin after cleansing, resulting in a good skin feel.

Embodiments for Carrying Out the Invention

[0009] The terms used in this specification are used in the meanings commonly used in the art, unless otherwise specified.

[0010] As used herein, the "skin cleansing composition" means a composition used for cleansing human skin, and includes hand soap, facial cleanser, body soap, etc.

[0011] One aspect of the present invention is a skin cleansing composition containing the following components (A) and (B), wherein the mass ratio (B / A) of component (B) to component (A) is 0.5 or more and less than 4. (A) An anionic surfactant containing a higher fatty acid or its salt (B) Particles containing a water-retaining oil agent, a humectant, and a polymer

[0012] Component (A) is an anionic surfactant containing a higher fatty acid or its salt. As described above, by blending a higher fatty acid or its salt, both excellent foaming property and a moist feeling of the skin after washing are achieved. Here, as the (A1) higher fatty acid or its salt, a fatty acid having 12 to 24 carbon atoms or its salt is preferable, a fatty acid having 12 to 18 carbon atoms or its salt is more preferable, and a fatty acid having 12 to 16 carbon atoms or its salt is still more preferable. Specifically, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid, arachidic acid, behenic acid, lignoceric acid, and salts thereof are preferable, and lauric acid, myristic acid, palmitic acid, and salts thereof are more preferable. Examples of these salts include alkali metal salts, alkaline earth metal salts, ammonium salts, organic ammonium salts, and basic amino acid salts. Specifically, alkali metal salts such as sodium salts and potassium salts; ammonium salts derived from alkanolamines such as monoethanolamine salts, diethanolamine salts, and triethanolamine salts; basic amino acid salts such as arginine salts and lysine salts, etc. can be mentioned. As the specific higher fatty acid or its salt, a sodium salt or a potassium salt of lauric acid, myristic acid, or palmitic acid is still more preferable. One or more of these higher fatty acids or their salts can be used, and they may be used alone or in combination of two or more.

[0013] Component (A) may contain another anionic surfactant (A2) in addition to the higher fatty acid or its salt. Examples of the other anionic surfactant (A2) include polyoxyethylene alkyl ether carboxylic acid or its salt, alkyl phosphoric acid or its salt, polyoxyethylene alkyl ether phosphoric acid or its salt, alkyl sulfate ester or its salt, polyoxyethylene alkyl ether sulfate ester or its salt, acylated amino acid or its salt, fatty acid amide sulfonic acid or its salt, sulfosuccinic acid or its salt, and the like. Among these anionic surfactants, those having a hydrocarbon group with 12 to 24 carbon atoms, more preferably 12 to 16 carbon atoms, and still more preferably 12 to 14 carbon atoms are preferred. Examples of the polyoxyethylene alkyl ether carboxylic acid or its salt include sodium polyoxyethylene alkyl ether acetate. Examples of the alkyl phosphoric acid or its salt include potassium lauryl phosphate, sodium lauryl phosphate, arginine lauryl phosphate, potassium myristyl phosphate, sodium myristyl phosphate, arginine myristyl phosphate, potassium palmityl phosphate, sodium palmityl phosphate, and arginine palmityl phosphate. Examples of the polyoxyethylene alkyl ether phosphoric acid or its salt include sodium polyoxyethylene oleyl ether phosphate and sodium polyoxyethylene stearyl ether phosphate. Examples of the alkyl sulfate ester or its salt include sodium lauryl sulfate and potassium lauryl sulfate. Examples of the polyoxyethylene alkyl ether sulfate ester or its salt include potassium polyoxyethylene lauryl sulfate, sodium polyoxyethylene lauryl sulfate, and triethanolamine polyoxyethylene lauryl sulfate. Examples of the acylated amino acid or its salt include sodium lauroyl sarcosinate, monosodium N-lauroyl glutamate, disodium N-stearoyl glutamate, monosodium N-myristoyl-L-glutamate, triethanolamine N-lauroyl glycine, potassium N-coconut fatty acid acyl glycine, triethanolamine N-lauroyl-β-alanine, and triethanolamine N-stearoyl-β-alanine. Examples of the fatty acid amide sulfonic acid or its salt include sodium N-myristoyl-N-methyl taurate and sodium N-stearoyl-N-methyl taurate. Examples of the sulfosuccinic acid or its salt include sodium di-2-ethylhexyl sulfosuccinate. These anionic surfactants can be used alone or in combination of two or more. Among these anionic surfactants, one or more selected from polyoxyethylene alkyl ether carboxylates, polyoxyethylene alkyl ether sulfates, and acylated amino acid salts are preferred from the viewpoints of foaming property and detergency, and one or more selected from polyoxyethylene alkyl ether carboxylates and polyoxyethylene alkyl ether sulfates are more preferred from the viewpoints of detergency and mildness to the skin.

[0014] Component (A) is preferably contained in the skin cleansing composition in an amount of 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, from the viewpoints of foaming property, moistening property, and cleaning performance. From the same viewpoints, it is preferably contained in an amount of 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less. Specifically, the content of component (A) is preferably 1% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 25% by mass or less, and even more preferably 3% by mass or more and 20% by mass or less in the skin cleansing composition.

[0015] Also, the mass ratio (A2 / A1) of the anionic surfactant (A2) other than the higher fatty acid or its salt in component (A) to the higher fatty acid or its salt (A1) is preferably 0 or more and 6 or less, more preferably 0 or more and 5 or less, even more preferably 0 or more and 4 or less, even more preferably 0 or more and 3 or less, and even more preferably 0 or more and 2.5 or less, from the viewpoints of obtaining good foaming and foam elasticity and achieving both moistening property.

[0016] Component (B) is particles containing (B1) a water-retaining oil agent, (B2) a humectant, and (B3) a polymer. By incorporating particles containing such components (B1), (B2), and (B3) into the skin cleansing composition, although only one cleansing agent is used, after washing away dirt such as sebum on the skin surface, components (B1) and (B2) are adsorbed onto the skin, and it is presumed that the moisturizing property is enhanced and the persistence of the moist feeling and the softness of the skin are realized.

[0017] (B1) The water-retaining oil agent is an oil agent having a water-retaining capacity equal to or more than its own weight (100% or more), and is an oil agent capable of retaining water equal to or more than its own weight at 50°C. In the present invention, the water-retaining capacity is an index indicating how much water the oil agent at 50°C can retain, and is evaluated as follows. That is, 10 g of a sample (oily component) heated to 50°C is weighed into a 200 mL beaker. While stirring at 3000 r / min with a disperser mixer, water at 50°C is gradually added until water is drained from the sample. The amount of water added (mass) until the drainage of water from the sample starts is measured. The added amount is divided by the mass of the sample, 10 g, to obtain a quotient. The numerical value obtained by multiplying the quotient by 100 is the water-retaining capacity (%).

[0018] Examples of such water-retaining oil agents include dimer acid esters, glycerin fatty acid esters, pentaerythritol fatty acid esters, cholesterol esters of fatty acids having 16 to 22 carbon atoms, phytosterol esters of fatty acids having 16 to 22 carbon atoms, N-acyl amino acid esters, and the like.

[0019] Examples of the dimer acid ester include an ester of a dimer acid and an alcohol, etc., an ester of dimer dilinoleic acid is preferred, and an ester of dimer dilinoleic acid and a dimer diol is more preferred. Further, as the ester moiety of the dimer acid or dimer dilinoleic acid, it preferably contains one or more moieties selected from behenyl, isostearyl, stearyl, cetyl, and phytosteryl, and more preferably contains two or more moieties selected from behenyl, isostearyl, stearyl, cetyl, and phytosteryl. More specifically, examples include dimer dilinoleic acid dimer dilinoleyl bis(behenyl / isostearyl / phytosteryl), dimer dilinoleic acid dimer dilinoleyl bis(phytosteryl / isostearyl / cetyl / stearyl / behenyl), dimer dilinoleic acid (phytosteryl / isostearyl / cetyl / stearyl / behenyl), dimer dilinoleic acid di(isostearyl / phytosteryl), and dilinoleyl distearate. Among them, dimer dilinoleic acid (phytosteryl / isostearyl / cetyl / stearyl / behenyl) and dimer dilinoleic acid di(isostearyl / phytosteryl) are preferred.

[0020] Examples of the glycerin fatty acid ester include glyceryl diisostearate, diglyceryl triisostearate, and tetraglyceryl pentastearate.

[0021] Examples of pentaerythritol fatty acid esters include pentaerythrityl tetra(behenate / benzoate / ethylhexanoate), pentaerythrityl tetra(ethylhexanoate / benzoate), dipentaerythrityl tripolyhydroxystearate, dipentaerythrityl hexa(hydroxystearate / stearate / rosinate), dipentaerythrityl (hydroxystearate / isostearate), dipentaerythrityl hexahydroxystearate, pentaerythrityl tetraethylhexanoate, pentaerythrityl tetraisostearate, dipentaerythritol (12-hydroxystearate / stearate / rosinate), dipentaerythritol (12-hydroxystearate / isostearate), and the like.

[0022] Examples of cholesterol esters of fatty acids having 16 to 22 carbon atoms include cholesterol palmitate, cholesteryl hydroxystearate, cholesterol stearate, cholesterol behenate, cholesterol isostearate, cholesterol oleate, cholesterol palmitooleate, cholesterol behenate, cholesterol linoleate, cholesterol linolenate, and the like. The fatty acid may be a mixed fatty acid, for example, cholesterol ester of sunflower seed oil fatty acid, cholesterol ester of macadamia nut oil fatty acid, and the like.

[0023] In addition, as the N-acyl amino acid ester, an alkyl ester of N-acyl amino acid is preferable. The number of carbon atoms of the alkyl group constituting the alkyl ester is preferably 1 to 30, more preferably 12 to 18. Further, the alkyl group may be branched, linear, or have a cyclic structure. Examples of such N-acyl amino acid esters include N-lauroyl-L-glutamic acid di(cholesteryl / behenyl / octyldodecyl), N-lauroyl-L-glutamic acid di(phytosteryl / behenyl / octyldodecyl), N-myristoyl-N-methylalanine (phytosteryl / decyltetradecyl), and the like.

[0024] As the component (B1), those having high water retention property, good compatibility with a humectant, and being likely to remain on the skin even after rinsing with water are preferred because the moist feeling and the non-stiff feeling after washing are sustained and the softness of the skin after washing is sustained. From this point, pentaerythritol fatty acid ester and fatty acid cholesteryl ester are more preferred, pentaerythritol fatty acid ester is further preferred, and dipentaerythrityl tripolyhydroxystearate is even more preferred.

[0025] The water-retaining oil agent of (B1) can be used by combining one kind or two or more kinds thereof. From the viewpoint of the sustainability of the moisturizing performance after washing, the content is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, still more preferably 0.01% by mass or more, and further preferably 0.03% by mass or more in the skin cleansing composition. From the viewpoint of improving the rinsability, suppressing stickiness during and after washing, and improving the storage stability of the cleansing agent, the content is preferably 13% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, even more preferably 2% by mass or less, and further preferably 1% by mass or less. The content of the water-retaining oil agent of (B1) is preferably 0.0001 to 13% by mass, more preferably 0.0001 to 10% by mass, still more preferably 0.001 to 5% by mass, even more preferably 0.01 to 2% by mass, and further preferably 0.03 to 1% by mass in the skin cleansing composition.

[0026] As the humectant of (B2), those used in ordinary cosmetics can be used, and either oily or water-soluble ones are acceptable. Examples of the oily humectant include oil agents that are liquid or solid at 25°C. Such an oil agent is not limited as long as it is used in ordinary skin cosmetics. For example, straight-chain or branched hydrocarbon oils such as squalene, squalane, liquid paraffin, liquid isoparaffin, heavy liquid isoparaffin, α-olefin oligomer, cycloparaffin, polybutene, petrolatum, paraffin wax, microcrystalline wax, polyethylene wax, ceresin, etc.; esters such as isononyl isononanoate, isodecyl isononanoate, isotridecyl isononanoate, tricyclodecane methyl isononanoate, ethyl isostearate, isobutyl isostearate, isopropyl isostearate, 2-hexyldecyl isostearate, isostearyl isostearate, di-2-hexylhexyl succinate, bis(ethoxydiglycol) succinate, hexyl laurate, di(caprylic / capric acid) propanediol, neopentyl glycol diisononanoate, neopentyl glycol dicaprate, glyceryl diisostearate, polyglyceryl diisostearate, propanediol diisostearate, trimethylolpropane triisostearate, glyceryl triisostearate, diglyceryl triisostearate, diglyceryl tetraisostearate, diisostearyl malate, octyldodecyl malate, glycerin fatty acid ester, jojoba oil, di(phytosteryl / octyldodecyl) lauroyl glutamate, octyldodecyl myristate, isopropyl myristate, 2-ethylhexyl palmitate, isopropyl palmitate, cetyl 2-ethylhexanoate, trimethylolpropane tri-2-ethylhexanoate, glyceryl tri-2-ethylhexanoate, octyldodecyl myristate, 2-hexyldecyl myristate, 2-hexyldecyl 2-ethylhexanoate, neopentyl glycol di-2-ethylhexanoate, 2-ethylhexyl hydroxystearate, tri(capryl / capric acid) glyceryl, glyceryl trioctanoate, neopentyl glycol dioctanoate; higher alcohols such as lauryl alcohol, oleyl alcohol, isostearyl alcohol, behenyl alcohol, octyldodecanol, etc. can be mentioned. Among these, from the viewpoint of further enhancing the skin softening effect after washing, having high moisture barrier property, no feeling of stickiness or tightness after washing, and maintaining the softness of the skin, hydrocarbon oils are preferred, and squalane and petrolatum are more preferred.

[0027] Examples of the water-soluble humectant include polyhydric alcohols. Examples of the polyhydric alcohols include dihydric alcohols such as ethylene glycol, diethylene glycol, hexylene glycol, polyethylene glycol with an average molecular weight of 10,000 or less, propylene glycol, 1,3-propanediol, dipropylene glycol, polypropylene glycol, isoprene glycol, 1,3-butylene glycol; trihydric or higher alcohols such as glycerin, diglycerin, triglycerin, tetraglycerin, hexaglycerin, decaglycerin, trimethylpropanol; sugars or sugar alcohols such as erythritol, pentaerythritol, dipentaerythritol, glucose, mannose, galactose, sucrose, fructose, maltose, maltitol, xylitol, inositol, sorbitan, sorbitol. Among these, glycerin is preferred from the viewpoint of improving the moist feeling after washing.

[0028] Component (B2) preferably contains an oily humectant, more preferably contains a hydrocarbon oil, more preferably contains one or two selected from squalane and petrolatum, and more preferably uses squalane and petrolatum in combination, from the viewpoints of further enhancing the moisturizing property after washing and further enhancing the persistence of the moist feeling after washing.

[0029] (B2) The humectant can be used alone or in combination of two or more kinds. From the viewpoint of the persistence of the moisturizing performance after washing, the content is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, further preferably 0.02% by mass or more, still more preferably 0.05% by mass or more in the skin cleansing composition. From the viewpoints of improving rinsability, suppressing stickiness during and after washing, and improving the storage stability of the cleansing agent, 25% by mass or less is preferable, 20% by mass or less is more preferable, 10% by mass or less is further preferable, 5% by mass or less is still more preferable, and 2% by mass or less is further preferable. The content of the humectant of (B2) is preferably 0.001 to 25% by mass, more preferably 0.001 to 20% by mass, further preferably 0.01 to 10% by mass, still more preferably 0.02 to 5% by mass, and further preferably 0.05 to 2% by mass in the skin cleansing composition.

[0030] In component (B), the mass ratio (B1) / (B2) of (B1) to (B2) is preferably 0.004 or more, more preferably 0.005 or more, further preferably 0.01 or more, still more preferably 0.05 or more, and even more preferably 0.15 or more from the viewpoint of reducing the squeaking feeling after washing and simultaneously satisfying the moist feeling, non-stiff feeling, and softness as the skin feel that persists after washing. Preferably 60 or less, more preferably 50 or less, further preferably 30 or less, still more preferably 20 or less, and even more preferably 1 or less. Also, the mass ratio (B1) / (B2) of (B1) to (B2) is preferably 0.004 to 60, more preferably 0.005 to 50, further preferably 0.01 to 30, still more preferably 0.05 to 20, and even more preferably 0.15 to 1.

[0031] The particles of component (B) further contain (B3) polymer. Component (B) may have (B1) and (B2) encapsulated in the (B3) polymer particles and / or (B1) and (B2) may be scattered on the surface. (B1) and (B2) may be either dispersed in the particles. From the viewpoint of suppressing the aggregation of particles and improving the storage stability of the cleaning agent, it is preferable that (B1) and (B2) are arranged inside the particles. For example, it is preferable that they are encapsulated or dispersed in the particles. Note that the fact that (B1) and (B2) are arranged inside the particles means not only a state where (B1) and (B2) are completely absent on the particle surface, but also includes those in which most of (B1) and (B2) are arranged inside the particles and a small amount adheres to the particle surface.

[0032] (B3) As the polymer, from the viewpoints of removing dirt such as sebum and imparting a moist feeling after washing, when the skin cleaning agent composition is familiarized with the skin or during rinsing, it is preferable that the particles disintegrate or dissolve. For example, a hydrophilic polymer is preferable. Furthermore, it is preferable that the hydrophilic polymer is a polymer whose solubility changes depending on the concentration of water-soluble salts (hereinafter referred to as a salt-sensitive polymer). Here, the salt-sensitive polymer means that when a 2 cm × 2 cm polymer sheet is placed in water with a salt concentration of 1% and stirred at 25°C for 5 minutes, the sheet completely dissolves when visually observed, while when the same test is performed with water having a salt concentration of 10%, the sheet does not dissolve when visually observed. When a salt-sensitive polymer is included as (B3), the particles of component (B) become particles whose solubility is improved by a decrease in the concentration of water-soluble salts (for example, sodium chloride, etc.) in the composition containing the particles (hereinafter referred to as salt-sensitive particles). When this salt-sensitive particle is blended in the skin cleaning agent composition, since the concentration of water-soluble salts is high in the skin cleaning agent composition, the particles do not disintegrate, and components (B1) and (B2) stably exist in the particles. On the other hand, in the process of familiarizing the skin cleaning agent composition with the skin and the rinsing process, when the concentration of water-soluble salts in the skin cleaning agent composition decreases, the solubility in water improves, the particles disintegrate, and components (B1) and (B2) are released. And since components (B1) and (B2) contained in the salt-sensitive particles are likely to remain on the skin after the dirt on the skin has fallen off, it is presumed that preferable results are obtained when (B3) contains a salt-sensitive polymer. That is, in the skin cleansing composition of the present invention, when salt-sensitive particles in which the water-retaining oil agent of component (B1) and the moisturizing agent of component (B2) are dispersed are used, when the skin cleansing composition is acclimated to the skin, the detergent is diluted and the salt concentration decreases. As a result, where the particle strength is reduced, when a physical force is applied by a finger or the like, the particles are more likely to collapse, and the components (B1) and (B2) in the particles are more likely to be released. Moreover, at the time of rinsing, since the detergent is further diluted and the salt concentration further decreases, the particles are even more likely to collapse, and the components (B1) and (B2) in the particles are more likely to be released. Therefore, after dirt such as sebum has fallen off, the (B1) water-retaining oil agent and the (B2) moisturizing agent are likely to remain on the skin, and the moisturizing effect can be further improved. In addition, when the water-retaining oil agent and the moisturizing agent are dispersed in the salt-sensitive particles, when compared in the same amount, it is considered that using particles containing a more finely dispersed water-retaining oil agent and moisturizing agent is more likely to adhere uniformly to the skin and the effect is improved. Further, since the water-retaining oil agent and the moisturizing agent are contained in the salt-sensitive particles, the skin cleansing agent containing the particles can suppress the separation of these components and has excellent storage stability.

[0033] Thus, when component (B) is a salt-sensitive particle, it is preferable to use acid-modified polyvinyl alcohol as the polymer. Acid-modified polyvinyl alcohol is a polyvinyl alcohol having an acid group such as a sulfonic acid group, a sulfuric acid group, a carboxylic acid group, a phosphoric acid group, or a phosphonic acid group. From the viewpoints of storage stability in the skin cleansing agent and the disintegrability due to a decrease in the concentration of water-soluble salts during washing (during washing and rinsing), acid-modified polyvinyl alcohol into which one or two selected from a sulfonic acid group and a carboxylic acid group are introduced is more preferable, and acid-modified polyvinyl alcohol into which a carboxylic acid group is introduced (hereinafter, also referred to as "carboxylic acid-modified polyvinyl alcohol") is even more preferable.

[0034] Examples of the carboxylic acid-modified polyvinyl alcohol include those obtained by (1) graft polymerization or block polymerization of polyvinyl alcohol and an unsaturated monomer having a carboxy group, (2) copolymerization of a vinyl ester compound and an unsaturated monomer having at least one selected from a carboxy group (carboxylic acid group) and a carboxylic acid ester group, followed by saponification, (3) polymerization of a vinyl ester compound using a chain transfer agent having a carboxy group, followed by saponification, and (4) reaction of polyvinyl alcohol with a carboxylating agent.

[0035] Examples of the unsaturated monomer having a carboxy group used in the methods (1) and (2) above and the unsaturated monomer having a carboxylic acid ester group used in the method (2) include ethylenically unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; ethylenically unsaturated dicarboxylic acid monoesters such as maleic acid monoalkyl ester, fumaric acid monoalkyl ester, and itaconic acid monoalkyl ester; ethylenically unsaturated dicarboxylic acid diesters such as maleic acid dialkyl ester, fumaric acid dialkyl ester, and itaconic acid dialkyl ester; ethylenically unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride; unsaturated monocarboxylic acids such as (meth)acrylic acid; and unsaturated monocarboxylic acid esters such as (meth)acrylic acid alkyl ester. Further, salts of the above compounds may be used as the unsaturated monomer having at least one selected from a carboxy group and a carboxylic acid ester group. Among these, from the viewpoint of reactivity, ethylenically unsaturated carboxylic acid monoesters are preferred, ethylenically unsaturated dicarboxylic acid monoesters are more preferred, maleic acid monoalkyl esters and itaconic acid monoalkyl esters are still more preferred, and maleic acid monoalkyl esters are even more preferred. These compounds may be used alone or in combination of two or more.

[0036] Examples of the vinyl ester compounds used in the above methods (2) and (3) include vinyl acetate, vinyl formate, vinyl propionate, vinyl versatate, vinyl pivalate, and the like. Among these, vinyl acetate is preferred from the viewpoints of reactivity during synthesis and ease of availability. These compounds may be used alone or in combination of two or more.

[0037] Examples of the carboxylating agent used in the above method (4) include carboxylic acid anhydrides such as succinic anhydride, maleic anhydride, acetic anhydride, trimellitic anhydride, phthalic anhydride, pyromellitic anhydride, glutaric anhydride, hydrogenated phthalic anhydride, and naphthalenedicarboxylic anhydride. These may be used alone or in combination of two or more.

[0038] From the viewpoint of improving the release properties of components (B1) and (B2) due to the decrease in the concentration of water-soluble salts, the acid modification rate (the ratio of the monomer having an acid group) in the acid-modified polyvinyl alcohol is preferably 0.1 mol% or more, more preferably 0.5 mol% or more, and still more preferably 1 mol% or more. From the viewpoint of the storage stability of component (B) in the skin cleanser, it is preferably 10 mol% or less, more preferably 5 mol% or less, and still more preferably 3 mol% or less. Therefore, from the viewpoints of improving the release properties of components (B1) and (B2) due to the decrease in the concentration of water-soluble salts and the storage stability of component (B) in the skin cleanser, the acid modification rate in the acid-modified polyvinyl alcohol is preferably 0.1 mol% or more and 10 mol% or less, more preferably 0.5 mol% or more and 5 mol% or less, and still more preferably 1 mol% or more and 3 mol% or less. The acid modification rate in the acid-modified polyvinyl alcohol can be determined by analyzing the acid-modified polyvinyl alcohol before saponification using 1 1H-NMR (solvent: CDCl3).

[0039] The saponification degree of the acid-modified polyvinyl alcohol is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, from the viewpoint of storage stability in the skin cleansing composition of component (B). From the viewpoint of improving the release properties of components (B1) and (B2) due to the decrease in the concentration of water-soluble salts, it is preferably 99.9 mol% or less, more preferably 99.5 mol% or less, still more preferably 99 mol% or less. Therefore, from the viewpoints of improving the release properties of components (B1) and (B2) due to the decrease in the concentration of water-soluble salts and the storage stability of component (B) in the skin cleansing composition, the saponification degree of the acid-modified polyvinyl alcohol is preferably 70 mol% or more and 99.9 mol% or less, more preferably 80 mol% or more and 99.5 mol% or less, still more preferably 90 mol% or more and 99 mol% or less. The saponification degree of the acid-modified polyvinyl alcohol is measured in accordance with JIS K6726:1994.

[0040] The degree of polymerization of the acid-modified polyvinyl alcohol is preferably 100 or more, more preferably 500 or more, still more preferably 1,000 or more, from the viewpoint of storage (granule) stability in the skin cleansing composition of component (B). From the viewpoint of improving the release properties of components (B1) and (B2) due to the decrease in the concentration of water-soluble salts, it is preferably 200,000 or less, more preferably 10,000 or less, still more preferably 4,000 or less. Therefore, from the viewpoints of improving the release properties of components (B1) and (B2) due to the decrease in the concentration of water-soluble salts and the storage stability of component (B) in the skin cleansing composition, the degree of polymerization of the acid-modified polyvinyl alcohol is preferably 100 or more and 200,000 or less, more preferably 500 or more and 10,000 or less, still more preferably 1,000 or more and 4,000 or less. The degree of polymerization of the acid-modified polyvinyl alcohol can be calculated from the relative viscosity of an aqueous solution of fully saponified polyvinyl alcohol and water (see JIS K6726:1994).

[0041] Also, from the viewpoint of storage stability in the skin cleansing composition of component (B), the molecular weight of the acid-modified polyvinyl alcohol is preferably 5,000 or more, more preferably 10,000 or more, still more preferably 30,000 or more, even more preferably 50,000 or more, and from the viewpoint of improving the release properties of components (B1) and (B2) due to the decrease in the concentration of water-soluble salts, it is preferably 1,000,000 or less, more preferably 500,000 or less, still more preferably 200,000 or less. Therefore, from the viewpoint of improving the release properties of components (B1) and (B2) due to the decrease in the concentration of water-soluble salts and the viewpoint of storage stability in the skin cleansing composition of the salt-sensitive particles, the molecular weight of the acid-modified polyvinyl alcohol is preferably 5,000 or more and 1,000,000 or less, more preferably 10,000 or more and 500,000 or less, still more preferably 30,000 or more and 200,000 or less, even more preferably 50,000 or more and 200,000 or less. The molecular weight of the acid-modified polyvinyl alcohol can be determined by calculation from the degree of polymerization.

[0042] Specific examples of the acid-modified polyvinyl alcohol include KL-118, KL-318, KL-506, KM-118, KM-618 manufactured by Kuraray Co., Ltd.; Gosenex CKS50, Gosenex T-330H, Gosenex T-330, Gosenex T-350 manufactured by Mitsubishi Chemical Corporation; AP-17, AT-17, and AF-17 of Nippon Vinyl Poval Co., Ltd., and the like.

[0043] From the viewpoint of exerting the effect of salt sensitivity, the content of the acid-modified polyvinyl alcohol in component (B) is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, even more preferably 20% by mass or more, still more preferably 40% by mass or more, and from the viewpoint of containing other components such as components (B1) and (B2), it is preferably 99% by mass or less, more preferably 95% by mass or less, still more preferably 90% by mass or less, even more preferably 85% by mass or less, still more preferably 80% by mass or less. From the above viewpoints, the content of the acid-modified polyvinyl alcohol in component (B) is preferably 1% by mass or more and 99% by mass or less, more preferably 5% by mass or more and 95% by mass or less, still more preferably 10% by mass or more and 90% by mass or less, even more preferably 20% by mass or more and 85% by mass or less, and still more preferably 40% by mass or more and 80% by mass or less.

[0044] The acid-modified polyvinyl alcohol forms the matrix of component (B). That is, it is the polymer component corresponding to the sea part of the sea-island structure. As the polymer component of component (B3), in addition to the acid-modified polyvinyl alcohol, other polymers and other additives may be contained. From the viewpoint of obtaining good salt sensitivity, the content of the acid-modified polyvinyl alcohol in component (B3) is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 90% by mass or more, even more preferably 95% by mass or more, and may be 100% by mass.

[0045] From the viewpoint of exerting the effects of components (B1) and (B2), the content of components (B1) and (B2) in component (B) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1% by mass or more, even more preferably 5% by mass or more, and still more preferably 10% by mass or more. From the viewpoint of suppressing the leakage of components (B1) and (B2) from component (B), the content is preferably 80% by mass or less, more preferably 70% by mass or less, still more preferably 60% by mass or less, even more preferably 50% by mass or less, and still more preferably 40% by mass or less. From the above viewpoints, the content of components (B1) and (B2) in component (B) is preferably 0.1 to 80% by mass, more preferably 0.5 to 70% by mass, still more preferably 1 to 60% by mass, even more preferably 5 to 50% by mass, and still more preferably 10 to 40% by mass.

[0046] The mass ratio of the content of the acid-modified polyvinyl alcohol to the contents of components (B1) and (B2) contained in component (B) (acid-modified polyvinyl alcohol / components (B1) and (B2)) is preferably 0.1 or more, more preferably 0.3 or more, still more preferably 0.5 or more, even more preferably 0.7 or more, and further more preferably 1 or more from the viewpoint of suppressing the leakage of components (B1) and (B2) from component (B), and preferably 90 or less, more preferably 70 or less, still more preferably 50 or less, even more preferably 30 or less, and further more preferably 10 or less from the viewpoint of efficiently containing components (B1) and (B2).

[0047] In addition, the particles of component (B) can further contain water-insoluble particles, surfactants, colorants (dyes, pigments, etc.), preservatives, fragrances, thickeners, cooling agents, astringents, bactericides, ultraviolet absorbers, whitening agents, anti-inflammatory agents, etc. In addition to (B1) and (B2), component (B) can contain oily components such as the above-mentioned fragrances, surfactants, and ultraviolet absorbers (hereinafter, (B1), (B2), and other oily components are collectively referred to as an oil agent). However, the mass ratio of the acid-modified polyvinyl alcohol / oil agent contained in component (B) is preferably 0.1 to 90, more preferably 0.3 to 70, still more preferably 0.5 to 50, even more preferably 0.7 to 30, and further more preferably 1 to 10 from the above viewpoints.

[0048] The average particle size (dry product physical properties) of component (B) is preferably 1,500 μm or less, more preferably 1,000 μm or less, still more preferably 500 μm or less, even more preferably 200 μm or less, and further more preferably 100 μm or less from the viewpoint of the feeling of use when formulated in the skin cleansing composition, and preferably 1 μm or more, more preferably 5 μm or more, still more preferably 10 μm or more, even more preferably 20 μm or more, and further more preferably 30 μm or more from the viewpoint of containing components (B1) and (B2). From the above viewpoints, the average particle size (physical properties of the dried product) of component (B) is preferably 1 to 1,500 μm, more preferably 5 to 1,000 μm, still more preferably 10 to 500 μm, even more preferably 20 to 200 μm, and particularly preferably 30 to 100 μm. In the present invention, the average particle size of component (B) is measured using a laser diffraction / scattering particle size distribution analyzer LA-920 (manufactured by Horiba, Ltd.), and the median diameter is taken as the average particle size.

[0049] Component (B) can be produced, for example, by removing water from an emulsified composition containing component (B1) and (B2) and component (B3).

[0050] The particles of component (B) can be used alone or in combination of two or more. From the viewpoints of moisturizing performance and its sustainability, the content is preferably 0.001% by mass or more, more preferably 0.1% by mass or more, still more preferably 1% by mass or more in the skin cleansing composition. From the viewpoint of uniformly blending into the skin cleansing composition, it is preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 20% by mass or less. Also, the content of component (B) is preferably 0.001 to 50% by mass, more preferably 0.1 to 40% by mass, still more preferably 1 to 20% by mass in the skin cleansing composition.

[0051] In the skin cleansing composition of the present invention, from the viewpoint of achieving both excellent foaming power and imparting a moist feeling to the skin after washing, the mass ratio (B / A) of component (B) to component (A) is preferably 0.5 or more and less than 4, more preferably 0.5 or more and 3.8 or less, still more preferably 0.5 or more and 2.5 or less.

[0052] In addition to the above components (A) and (B), the skin cleansing composition of the present invention can contain (C) surfactants other than component (A), (D) water, (E) viscosity modifiers, feel modifiers, and other components.

[0053] As the surfactant other than the component (A), amphoteric surfactants, nonionic surfactants, and cationic surfactants can be mentioned, but it is preferable to use one or more selected from (C1) amphoteric surfactants and (C2) nonionic surfactants. Examples of the (C1) amphoteric surfactant include carboxylic acid type amphoteric surfactants, sulfonic acid type amphoteric surfactants, phosphoric acid ester type amphoteric surfactants, and the like. Examples of the carboxylic acid type amphoteric surfactant include alkylamidopropyl betaine, alkyldimethylaminoacetic acid betaine, etc. Examples of the sulfonic acid type amphoteric surfactant include alkylhydroxysulfobetaine, etc. Examples of the phosphoric acid ester type amphoteric surfactant include alkylhydroxyphosphobetaine, etc. Among these, sulfonic acid type amphoteric surfactants are preferable, and alkylhydroxysulfobetaine is more preferable in terms of foaming, viscosity adjustment, and temperature stability.

[0054] One or more of the component (C1) can be used, and from the viewpoints of foaming, viscosity adjustment, and temperature stability, it is preferably contained in the skin cleansing composition in an amount of 0 to 20% by mass, more preferably 0 to 10% by mass, and even more preferably 0.5 to 5% by mass.

[0055] (C2) A nonionic surfactant can be added to control the stability and feel of use of the product. Examples of nonionic surfactants include sorbitan fatty acid esters such as sorbitan monostearate; polyglycerin fatty acid esters such as glycerin fatty acid ester and polyglyceryl monoisostearate; polyoxyethylene fatty acid esters such as propylene glycol fatty acid ester and polyethylene glycol monolaurate; sucrose fatty acid ester; polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monostearate, and polyoxyethylene coconut oil fatty acid sorbitan; polyoxyethylene alkyl ether; glycerin monoalkyl ethers such as ethylhexyl glycerin; polyoxyethylene sorbitol fatty acid ester; polyoxyethylene glycerin fatty acid ester; polyoxyethylene propylene glycol fatty acid ester; polyoxyethylene castor oil; polyoxyethylene hydrogenated castor oil; polyoxyethylene hydrogenated castor oil fatty acid ester; alkyl polyglucoside; polyoxyalkylene-modified silicones such as polyoxyethylene-methylpolysiloxane copolymer, etc. Among these nonionic surfactants, polyoxyethylene alkyl ether, glycerin monoalkyl ether, and alkyl polyglucoside are preferred in terms of lack of roughness, viscosity adjustability, and moist feeling after washing.

[0056] (C2) The nonionic surfactant can be used alone or in combination of two or more. From the viewpoints of detergency and skin feel during and after washing, the content is preferably 0 to 30% by mass, more preferably 0.01 to 20% by mass, and even more preferably 0.1 to 10% by mass in the skin cleansing agent composition.

[0057] In the present invention, the water content of (D) may usually be 1% by mass or more and 90% by mass, but the water content of (D) determines the salt concentration that affects the stability of component (B). From the viewpoints of the stability of (B) and the solubility of components other than (B) in the skin cleansing composition, it is more preferably 40% by mass or less. By setting the water content of (D) to 40% by mass or less, the dispersibility of (B) particles is improved, and it is more preferable because disappearance of the particles and gelation of the cleansing composition during storage can be prevented. The water content of (D) is preferably 1% by mass or more in the skin cleansing composition, more preferably 5% by mass or more, further preferably 7% by mass or more, preferably 40% by mass or less, and more preferably 35% by mass or less.

[0058] Examples of the viscosity modifier (E) include acrylic polymers such as acrylates / acrylic acid alkyl (C10-C30) cross polymer, carboxyvinyl polymer, (hydroxyethyl acrylate / acryloyldimethyltaurine Na) copolymer, (acryloyldimethyltaurine ammonium / vinylpyrrolidone) copolymer; cellulose derivatives such as hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, gums such as xanthan gum, fatty acid glyceryls such as glyceryl (behenate / eicosanedioate), isocyanate copolymers such as (PEG-240 / decyltetradeceth-20 / HDI) copolymer, and inorganic minerals such as silica, kaolin, and smectite. Acrylic polymers and cellulose derivatives are preferred from the viewpoints of viscosity adjustment, foaming, and non-stickiness. Examples of the feel modifier (E) include N-acyl amino acid esters such as lauroyl glutamate (phytosteryl / octyldodecyl), polyquaterniums, polyglycerin, glycerin, propylene glycol, dipropylene glycol, polyols such as polyoxyalkylene alkyl glucoside, and saccharides such as sorbitol and maltitol.

[0059] In addition to the above components, the skin cleansing composition of the present invention can use components commonly used in ordinary cleansing compositions as long as the effects of the present invention are not impaired. For example, lower alcohols such as ethanol and isopropyl alcohol; aromatic alcohols such as benzyl alcohol and benzyloxyethanol; cellosolves such as ethyl cellosolve and butyl cellosolve; carbitols such as ethyl carbitol and butyl carbitol; moisturizing components such as sugars or their derivatives, amino acids or their derivatives, proteins derived from animals and plants or their derivatives, and extracts of animals and plants; silicone derivatives such as polyoxyalkylene-modified silicone; inorganic or organic salts such as sodium sulfate, sodium carbonate, sodium hydrogen carbonate, potassium chloride, sodium chloride, and sodium citrate; pH adjusters such as acids and alkalis; anti-inflammatory agents such as glycyrrhetinic acid, glycyrrhizic acid, and their derivatives; bactericides such as isopropylmethylphenol; preservatives, sequestering agents, antioxidants, ultraviolet absorbers, anionic polymers, nonionic polymers, amphoteric polymers, fragrances, thickeners, cooling agents, vitamins, natural pigments, coloring agents other than the above such as tar pigments and charcoal, scrubbing agents such as cellulose powder and ground plant seeds, and the like can be mentioned.

[0060] In the skin cleansing composition of the present invention, from the viewpoints of the stability and skin irritation of (B), the salt content in the skin cleansing composition is preferably 2 to 70% by mass, more preferably 5 to 50% by mass, still more preferably 7 to 35% by mass, and even more preferably 7 to 30% by mass, based on the water content. In the skin cleansing composition of the present invention, the salt concentration is the salt concentration with respect to (D) water, and the salt may include an anionic surfactant, component (E), a chelating agent, and the like.

[0061] The skin cleansing composition of the present invention can be produced by a usual method, and preferably contains (D) water to form an aqueous skin cleansing composition. It can be in the form of a liquid, cream, gel, solid soap, or the like. The skin cleansing composition of the present invention is used for skin cleansing, and more preferably used as hand soap, facial cleanser, body soap, or the like.

[0062] Another aspect of the present invention is a method for cleaning the skin, characterized in that after applying a skin cleansing composition containing the following components (A) and (B) to the skin and rinsing with water, the mass ratio (B / A) of component (B) to component (A) is 0.5 or more and less than 4. (A) An anionic surfactant containing a higher fatty acid or a salt thereof (B) Particles containing a water-retaining oil agent, a moisturizing agent, and a polymer Here, the skin cleansing composition to be used is as described above. Specifically, the skin can be cleaned by applying the skin cleansing composition of the present invention to the skin and then rinsing with water, for example. When washing the face, it is preferable to lightly wet the entire face and hands with water and then spread the agent evenly over the entire face.

[0063] Regarding the above-described embodiments, the present invention further discloses the following compositions. <1>A skin cleansing composition containing the following components (A) and (B), wherein the mass ratio (B / A) of component (B) to component (A) is 0.5 or more and less than 4. (A) An anionic surfactant containing a higher fatty acid or a salt thereof (B) Particles containing a water-retaining oil agent, a moisturizing agent, and a polymer <2>The skin cleansing composition according to <1>, wherein the anionic surfactant other than the higher fatty acid or its salt contained in component (A) is one or more selected from polyoxyethylene alkyl ether carboxylic acid or its salt, alkyl phosphate or its salt, polyoxyethylene alkyl ether phosphate or its salt, alkyl sulfate ester or its salt, polyoxyethylene alkyl ether sulfate ester or its salt, acylated amino acid or its salt, fatty acid amide sulfonic acid or its salt, and sulfosuccinic acid or its salt, preferably one or more selected from polyoxyethylene alkyl ether carboxylate and polyoxyethylene alkyl ether sulfate ester salt. <3>The skin cleansing composition according to <1> or <2>, wherein the content of component (A) is preferably 1% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 25% by mass or less, and even more preferably 3% by mass or more and 20% by mass or less in the skin cleansing composition. <4>It is preferable that the mass ratio (A2 / A1) of the anionic surfactant (A2) other than the higher fatty acid or its salt in component (A) to the higher fatty acid or its salt (A1) is 0 or more and 6 or less, more preferably 0 or more and 5 or less, still more preferably 0 or more and 4 or less, even more preferably 0 or more and 3 or less, and still more preferably 0 or more and 2.5 or less. The skin cleansing composition according to any one of <1> to <3>. <5>The skin cleansing composition according to any one of <1> to <4>, wherein component (B) contains (B1) a water-retaining oil agent in an amount of 0.0001% by mass to 13% by mass in the skin cleansing agent, (B2) a humectant in an amount of 0.001% by mass or more and 25% by mass or less, and (B3) particles containing a polymer. <6>The skin cleansing composition according to any one of <1> to <5>, wherein the (B1) water-retaining oil agent is one or more selected from dimer acid esters, glycerin fatty acid esters, pentaerythritol fatty acid esters, cholesterol esters of fatty acids having 16 to 22 carbon atoms, phytosterol esters of fatty acids having 16 to 22 carbon atoms, and N-acyl amino acid esters. <7>The skin cleansing composition according to any one of <1> to <6>, wherein the (B2) humectant is one or more selected from hydrocarbon oils and polyhydric alcohols. <8>The skin cleansing composition according to any one of <1> to <7>, wherein the (B3) polymer is a salt-sensitive polymer, and acid-modified polyvinyl alcohol is preferred. <9>It is preferable that the content of acid-modified polyvinyl alcohol in component (B) is 1% by mass or more and 99% by mass or less, more preferably 5% by mass or more and 95% by mass or less, still more preferably 10% by mass or more and 90% by mass or less, even more preferably 20% by mass or more and 85% by mass or less, and still more preferably 40% by mass or more and 80% by mass or less. The skin cleansing composition according to <8>. <10>The skin cleansing composition according to any one of <1> to <9>, wherein the average particle size (dry product physical properties) of component (B) is preferably 1 to 1,500 μm, more preferably 5 to 1,000 μm, still more preferably 10 to 500 μm, even more preferably 20 to 200 μm, and still more preferably 30 to 100 μm. <11>The skin cleansing composition according to any one of <1> to <10>, wherein the mass ratio (B / A) of component (B) to component (A) is preferably 0.5 or more and 2.5 or less, more preferably 0.5 or more and 2 or less. <12>Furthermore, the skin cleansing composition according to any one of <1> to <11>, which contains (C) one or more selected from surfactants other than the anionic surfactant, (D) water, and (E) one or more selected from a viscosity modifier and a feel modifier. <13>The skin cleansing composition according to <12>, wherein (C) the surfactant other than the anionic surfactant is one or more selected from (C1) an amphoteric surfactant and (C2) a nonionic surfactant. <14>The skin cleansing composition according to <12> or <13>, wherein the content of (D) water is preferably 40% by mass or less, preferably 1 to 40% by mass, more preferably 1 to 35% by mass, and even more preferably 5 to 35% by mass in the skin cleansing composition. <15>The skin cleansing composition according to any one of <12> to <14>, wherein (E) the viscosity modifier is one or more selected from an acrylic acid polymer and a cellulose derivative. <16>The skin cleansing composition according to any one of <12> to <15>, wherein (E) the feel modifier is one or more selected from N-acyl amino acid esters, polyquaterniums, and polyols. <17>The skin cleansing composition according to any one of <1> to <16>, which is selected from hand soap, facial cleanser, and body soap. <18>A method for cleansing the skin, which comprises applying a skin cleansing composition containing the following components (A) and (B) and having a mass ratio (B / A) of component (B) to component (A) of 0.5 or more and less than 4 to the skin and then rinsing with water. (A) An anionic surfactant containing a higher fatty acid or a salt thereof (B) Particles containing a water-retaining oil agent, a moisturizing agent, and a polymer

Examples

[0064] Next, the present invention will be described in more detail with reference to examples, but the examples are merely illustrative and the present invention is not limited to these examples.

[0065] Examples 1 to 15, Comparative Examples 1 to 7 Skin cleansing agent compositions having the compositions shown in Tables 1 to 4 were produced, and the foaming property and the moist feeling after washing were evaluated. Further, for Examples 13 to 15, the uniformity of the foam and the dispersion state of the particles on the day after production were also evaluated. The uniformity of the foam was regarded as uniform when the whole was filled with foam without the liquid being visible after foaming, and non-uniform when a liquid composition was visible. The dispersibility of the particles was regarded as being dispersed as particles when the solution had fluidity on the next day, and not being in a particulate state due to swelling of the particles when there was no fluidity. The particles of component (B) described in the table were produced in the same manner as in Production Example 1 below. Further, the compounding amounts (% by mass) described in the table are effective amounts.

[0066] Production Example 1 To 76.59 kg of ion-exchanged water, 14.01 kg of (maleic acid / vinyl alcohol) copolymer Na (Gosenex T-330H, manufactured by Mitsubishi Chemical Corporation) was added, and after mixing under heating at 80 °C, it was cooled to 75 °C to prepare an aqueous phase. 1.71 kg of dipentaerythrityl tripolyhydroxystearate (Saracos WO-6, manufactured by Nisshin Oillio Group), 1.71 kg of petrolatum (Super White Propet, manufactured by SONNEBORN), 3.43 kg of squalane (NIKKOL Squalane, manufactured by Nippon Surfactant Co., Ltd.), 1.54 kg of polyoxyethylene (20 EO) sorbitan monostearate (nonionic surfactant, Leodol TW-S120V, manufactured by Kao Corporation), and 0.51 kg of sorbitan stearate (nonionic surfactant, Leodol SP-S10V, manufactured by Kao Corporation) were mixed under heating at 75 °C to prepare an oil phase. The prepared oil phase was added to the aqueous phase, and while stirring using an anchor stirring blade and circulating the mixed phase, the circulating liquid was dispersed using a milder. Then, an appropriate amount of water was added to prepare an emulsion. The emulsion obtained by the above emulsification operation was spray-dried using a spray dryer to obtain particles of component (B). The composition of component (B) finally obtained by spray drying was 7.5% by mass of dipentaerythrityl tripolyhydroxystearate, 15.0% by mass of squalane, 7.5% by mass of petrolatum, 59.4% by mass of (maleic acid / vinyl alcohol) copolymer Na, 6.8% by mass of polyoxyethylene (20 EO) sorbitan monostearate, 2.3% by mass of sorbitan stearate, and 1.5% by mass of water. The average dry particle size of the obtained particles was 81 μm.

[0067] (Evaluation method) (1) Foaming evaluation Immediately after preparing each composition, 19 g of ion-exchanged water was added to 1 g of the composition in a foaming container (Daiso Industries Co., Ltd. Hoipurun, capacity 300 mL, product number 3781), and the amount of foam (mL) when foaming was reciprocated 50 times in about 15 seconds was measured. In the table, "Foaming of (i) solution only" shows the foaming evaluation result of the composition ((i) solution only) when the particles of component (B) in each example or comparative example are replaced with purified water. "Foaming with particles" shows the foaming evaluation result of the composition ((ii) with particles) of the example or comparative example in which the particles of component (B) are blended. "(i) / (ii)" indicates the ratio of the foam amount. When "(i) / (ii)" is 0.45 or more, it is considered that the foaming is maintained, and when it is less than 0.45, the foaming is considered to have decreased. (2) Moisture feeling evaluation "Using feeling of (ii)" shows the evaluation result evaluated by 5 professional panelists on the moisture feeling after massaging for 10 seconds using the foamed composition and rinsing 10 times with water. When 4 or more out of 5 people felt a moisture feeling with the composition ((ii) with particles) in which the particles of component (B) are blended compared to when washing with the composition ((i) solution only) in which the particles of component (B) are replaced with purified water, it is described as "moist", and when 3 or fewer out of 5 people felt a moisture feeling, it is described as "dry". The particles were added and uniformly mixed by stirring and mixing using a motor and / or as a mixed solution dispersed in a predetermined amount of glycerin and / or propylene glycol.

[0068]

Table 1

[0069] *1 Kao Akiho RLM-45 (90%) Active ingredient of Kao Corporation *2 Emal E-227 (27%) Active ingredient of Kao Corporation *3 Anhtol 20HD (30%) Active ingredient of Kao Corporation *4 Gosenecks t-330H Mitsubishi Chemical Corporation *5 Penetol GE-EH (90%) Active ingredient of Kao Corporation *6 Myadol 10 (40%) Active ingredient of Kao Corporation

[0070]

Table 2

[0071] *7 Amisoft LS-11 Ajinomoto Health Supply Co., Ltd.

[0072]

Table 3

[0073]

Table 4

[0074] *8 Erdyeu PS-203 Ajinomoto Co., Inc. *9 Markote 3331 Lubrizol Advanced Materials, Inc. *10 Carbopol ETD2020 Lubrizol Advanced Materials, Inc. *11 HEC DAICEL SE850 Daicel Corporation

[0075] From Tables 1 to 4, it can be seen that a skin cleansing composition containing (A) an anionic surfactant containing a higher fatty acid or a salt thereof, and (B) particles containing a water-retaining oil agent, a humectant, and a polymer, with the mass ratio (B / A) of component (B) to component (A) being 0.5 or more and less than 4, is excellent in foaming during washing and also excellent in the moist feeling after washing. It was found that a skin cleansing composition in which the mass ratio (B / A) is not 0.5 or more and less than 4, or a skin cleansing composition that does not contain a higher fatty acid or a salt thereof and contains sodium N-acylglutamate, a nonionic surfactant, and a polyoxyethylene alkyl sulfate, could not achieve both excellent foaming and a moist feeling after washing.

Claims

1. A skin cleansing composition containing the following components (A) and (B), wherein the mass ratio (B / A) of component (B) to component (A) is 0.5 or more and less than 4. (A) An anionic surfactant containing a higher fatty acid or a salt thereof (B) Particles containing a water-retaining oil agent (B1), a humectant (B2), and a polymer (B3)

2. The skin cleansing composition according to claim 1, wherein the mass ratio (A2 / A1) of the anionic surfactant (A2) other than the higher fatty acid or its salt in component (A) to the higher fatty acid or its salt (A1) is 0 or more and 6 or less.

3. The skin cleansing composition according to claim 1 or 2, containing 40% by mass or less of (D) water.

4. The anionic surfactant (A2) other than the higher fatty acid or its salt is one or more selected from polyoxyethylene alkyl ether carboxylic acid or its salt, alkyl phosphate or its salt, polyoxyethylene alkyl ether phosphate or its salt, alkyl sulfate ester or its salt, polyoxyethylene alkyl ether sulfate ester or its salt, acylated amino acid or its salt, fatty acid amide sulfonic acid or its salt, and sulfosuccinic acid or its salt. The skin cleansing composition according to claim 1 or 2.

5. The skin cleansing composition according to claim 1 or 2, further containing one or more selected from (C) amphoteric surfactants and nonionic surfactants.

6. Component (B) is particles containing (B1) a water-retaining oil agent in an amount of 0.0001% to 13% by mass in the skin cleansing agent, (B2) a humectant in an amount of 0.001% to 25% by mass in the skin cleansing agent, and (B3) a polymer. The skin cleansing composition according to claim 1 or 2.

7. A method for cleansing the skin, characterized in that a skin cleansing composition containing the following components (A) and (B), wherein the mass ratio (B / A) of component (B) to component (A) is 0.5 or more and less than 4, is applied to the skin and then rinsed with water. (A) An anionic surfactant containing a higher fatty acid or a salt thereof (B) Particles containing a water-retaining oil agent, a humectant, and a polymer

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