Liquid composition for cleansing skin

Abstract

To provide a liquid composition for skin cleansing which is used in an unconventional method.SOLUTION: A liquid composition for skin cleansing, which contains (A) a surfactant and (B) an amphiphilic ester and has a pH of from 3 to 8, while being contained in a spray container, is capable of exhibiting excellent cleansing power, while being reduced in the skin irritancy of a liquid composition for skin cleansing, and is able to provide a novel use that is different from conventional uses in which the liquid composition for skin cleansing is foamed before application to the skin, said novel use being direct spraying of the liquid composition for skin cleansing onto the skin.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a liquid composition for skin cleansing that can be cleansed without applying physical friction to the skin.

Background Art

[0002] As products for the purpose of cleansing the skin and keeping the skin clean, various skin cleansing composition products such as facial cleansers, body soaps, shampoos, etc. are provided. In the mechanism by which a skin cleansing composition cleanses the skin, a surfactant adsorbs to dirt and reduces the surface tension between the dirt and water. Together with the mechanical force due to friction, the dirt is made to float in water. In order for such a cleaning mechanism to act effectively, it is necessary to formulate the surfactant at a concentration above the critical micelle concentration.

[0003] On the other hand, there is also a current situation where the cleaning power of the surfactant is too strong, causing skin irritation, and as a result, skin problems such as dry skin are being caused. For this reason, various formulations have been proposed to devise the combination and blending amount of cleaning components, etc. for the purpose of making the action on the skin mild. Among these, since it is recognized that the foam formed during cleaning reduces the friction generated by direct contact between the skin and fingers, formulations that improve the foam quality such as the bubble force and the foam retention force are generally regarded as excellent formulations for making the action on the skin mild.

[0004] For this reason, in recent years, various pump-former type skin cleansing agents have been proposed, and not only the convenience of easily obtaining high-quality foam but also the gentleness to the skin have attracted attention. Specifically, in Patent Document 1, there is a liquid skin cleansing agent product comprising a former container and a liquid skin cleansing agent composition filled in this former container, wherein the liquid skin cleansing agent composition contains (A) 3 to 10% by mass of a specific fatty acid salt having a linear or branched monovalent hydrocarbon group with 7 to 21 carbon atoms, (B) a copolymer of a specific dimethyldiallylammonium chloride and acrylic acid and / or acrylamide, and (C) a sugar alcohol, and the content of component (A) and (B) A liquid skin cleansing product is disclosed in which the mass ratio (A) / (B) of the content of the components is 20 to 250. Furthermore, Patent Document 2 discloses a skin cleansing composition characterized by filling a foamer container with a cleansing agent containing (a) 2 to 9% by mass of a fatty acid salt, (b) 0.5 to 4% by mass of lauryldimethylaminoacetic acid betaine, and (c) 1 to 10% by mass of one or more types of dihydric alcohols, wherein the sum of the amounts (by mass) of components (a) and (b) (a) (a) is 3 to 10% by mass, and the ratio of amounts (b) / (a) is 0.1 to 0.5. Furthermore, Patent Document 3 discloses a cleansing composition that is dispensed from a foamer container, containing (a) lauryldimethylaminoacetic acid betaine and (b) 4 to 15% by mass of a higher fatty acid soap formed from fatty acids having 5 to 25 carbon atoms and having a specific composition. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2014 / 003114 [Patent Document 2] Japanese Unexamined Patent Publication No. 2016-098182 [Patent Document 3] International Publication No. 2017 / 081897 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Pump-foaming skin cleansing compositions contain relatively small amounts of surfactants, and in that respect, they tend to be less irritating to the skin compared to solid or semi-solid skin cleansing compositions. On the other hand, since pump-foaming skin cleansing compositions are designed to be dispensed as foam, it is unavoidable that they contain the minimum amount of surfactant necessary to generate foam.

[0007] Furthermore, while various skin cleansers have been developed to remove bodily fluids and dirt such as sebum and sweat (excluding those intended for makeup removal), all of them, without exception, are designed to be lathered before application to the skin. It is also common knowledge that lathering well before washing is preferable in that it reduces friction on the skin. Although foam can reduce physical friction by acting as an intermediary between the skin and the hands, the foam itself is rubbed against the skin, thus creating physical friction and causing irritation. In particular, irritation remains a concern for those with sensitive skin.

[0008] Thus, using skin cleansers in the same way as before limits the reduction of skin irritation. Therefore, it is considered necessary to make skin cleansers even less irritating to the skin so that they can be used even on skin that is sensitive to irritation.

[0009] Furthermore, in beauty salons and hair salons, facial cleansing treatments are sometimes performed, and in order to improve the quality of service, gentle cleansing treatments that are suitable for sensitive skin are desired.

[0010] Therefore, the present invention aims to provide a liquid composition for skin cleansing that can cleanse the skin without applying physical friction. [Means for solving the problem]

[0011] The inventors conceived a novel application for a skin cleansing liquid composition, which is applied directly to the skin without pre-lathering, in order to further reduce skin irritation, thus cleansing without applying physical friction to the skin. Furthermore, they discovered that by coexisting an amphiphilic ester with the surfactant, effective cleansing power can be obtained without applying physical friction to the skin. This invention was completed by further investigation based on this finding.

[0012] In other words, the present invention provides inventions in the following embodiments. Item 1. A liquid composition for cleansing the skin, comprising (A) a surfactant and (B) an amphiphilic ester, having a pH of 3 to 8, and used for cleansing without applying physical friction to the skin. Item 2. The liquid skin cleansing composition according to Item 1, wherein component (B) is selected from the group consisting of dicarboxylate bis(polyoxyalkylene alkyl ether) ester, dialkoxyalkyl dicarboxylate ester, and (eicosanedioic acid / tetradecanedioic acid) polyglyceryl-10. Item 3. The liquid composition for skin cleansing according to Item 2, wherein the dicarboxylic acid bis(polyoxyalkylene alkyl ether) ester is cyclohexane-1,4-dicarboxylic acid bisethoxydiglycol. Item 4. A liquid skin cleansing composition according to any one of items 1 to 3, wherein the content of component (A) is 0.025 to 2% by weight. Item 5. A liquid skin cleansing composition according to any one of items 1 to 4, applicable to sensitive skin. Item 6. A method for cleansing the skin, comprising applying a liquid composition for cleansing the skin, which contains (A) a surfactant and (B) an amphiphilic ester and has a pH of 3 to 8, to the skin without applying physical friction to the skin. [Effects of the Invention]

[0013] The liquid cleansing composition for skin of the present invention exhibits excellent cleansing power while reducing skin irritation, allowing for cleansing without pre-lathering or physical friction on the skin. Because cleansing is possible without physical friction, the amount of surfactant in the liquid cleansing composition for skin can be significantly reduced compared to conventional liquid cleansing compositions, thereby further reducing skin irritation. Therefore, the liquid cleansing composition for skin of the present invention can be suitably used for cleansing skin that is sensitive to irritation. [Modes for carrying out the invention]

[0014] 1. Liquid composition for skin cleansing The liquid composition for skin cleansing of the present invention is characterized by containing (A) a surfactant (hereinafter sometimes referred to as component (A)) and (B) an amphiphilic ester (hereinafter sometimes referred to as component (B)), and being adjusted to a predetermined pH. The liquid composition for skin cleansing of the present invention will be described in detail below.

[0015] (A) Surfactants The liquid composition for skin cleansing of the present invention contains a surfactant as component (A). The surfactant is not particularly limited, but from the viewpoint of suppressing skin irritation, anionic surfactants, nonionic surfactants, amphoteric surfactants, natural surfactants, etc., are preferred. As the surfactant, one of the anionic surfactants, nonionic surfactants, amphoteric surfactants, and natural surfactants may be used alone, or two or more may be used in any combination.

[0016] Examples of anionic surfactants used in the present invention include carboxylic acid type, sulfonic acid type, sulfate ester type, and phosphate ester type surfactants.

[0017] Examples of carboxylic acid-type surfactants include saturated or unsaturated fatty acids with 6 to 22 carbon atoms, such as octanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, and stearic acid; and N-acyl amino acids (carboxylic acid-type amino acid-based anionic surfactants) having saturated or unsaturated N-acyl groups with 8 to 24 carbon atoms, such as octanoyl, decanoyl, lauroyl, myristoyl, palmitoyl, and cocoyl groups.

[0018] Examples of carboxylic acid-type amino acid-based anionic surfactants include N-acyl amino acids having saturated or unsaturated N-acyl groups with 8 to 24 carbon atoms, such as octanoyl, decanoyl, lauroyl, myristoyl, palmitoyl, and cocoyl groups. Examples of N-acyl amino acids in carboxylic acid-type amino acid-based anionic surfactants include N-acyl sarcosine, N-acyl aspartic acid, N-acyl glutamic acid, and N-acyl-N-methyl-β-alanine. More specific examples of carboxylic acid-type amino acid-based anionic surfactants include N-lauroyl sarcosine, cocoyl sarcosine, N-lauroyl aspartic acid, cocoyl aspartic acid, N-lauroyl glutamic acid, cocoyl glutamic acid, N-lauroyl-N-methyl-β-alanine, and cocoyl methyl alanine.

[0019] Examples of sulfonic acid-type surfactants include esters of isethionic acid with a C6-C22 fatty acid such as cocoyl isethionic acid; alkyl sulfonic acids with C6-C22 such as hexanesulfonic acid, octanesulfonic acid, decanesulfonic acid, and dodecanesulfonic acid; alkylbenzenesulfonic acids having an alkyl group with C10-C16 such as alkylbenzenesulfonic acid; and N-acyl-N-methyl taurine (sulfonic acid-type amino acid-based anionic surfactant) having a saturated or unsaturated N-acyl group with C8-C24 such as octanoyl, decanoyl, lauroyl, myristoyl, palmitoyl, and cocoyl groups.

[0020] Examples of sulfonic acid-type amino acid-based anionic surfactants include N-acyl-N-methyltaurine, which has saturated or unsaturated N-acyl groups with 8 to 24 carbon atoms, such as octanoyl, decanoyl, lauroyl, myristoyl, palmitoyl, and cocoyl groups. More specific examples of sulfonic acid-type amino acid-based anionic surfactants include N-myristoyl-N-methyltaurine, N-lauroyl-N-methyltaurine, and cocoyl methyltaurine.

[0021] Examples of sulfate surfactants include esters of saturated or unsaturated fatty acids having 10 to 22 carbon atoms, such as lauryl sulfate and myristyl sulfate, with sulfuric acid. Examples of phosphate surfactants include esters of saturated or unsaturated fatty acids having 8 to 24 carbon atoms, such as lauryl phosphate, with phosphoric acid.

[0022] These anionic surfactants may be in the form of salts, for example, alkali metal salts such as sodium salts and potassium salts; triethanolamine (TEA) salts; ammonium salts and the like.

[0023] Among these anionic surfactants, from the viewpoints of reducing skin irritation and obtaining better detergency, carboxylic acid type surfactants and sulfonic acid type surfactants are preferably used, and more preferably, carboxylic acid type amino acid based anionic surfactants and sulfonic acid type amino acid based anionic surfactants are used. Carboxylic acid type amino acid based anionic surfactants and sulfonic acid type amino acid based anionic surfactants are preferably used from the viewpoint of suppressing the feeling of tightness due to insufficient moisturization or from the viewpoints of suppressing the feeling of tightness due to insufficient moisturization and detergency when the pH of the liquid composition for skin cleansing of the present invention is, for example, 3 to 6. More specifically, carboxylic acid type amino acid based anionic surfactants and sulfonic acid type amino acid based anionic surfactants are preferably used from the viewpoint of suppressing the feeling of tightness due to insufficient moisturization when the pH of the liquid composition for skin cleansing of the present invention is, for example, 3 to 4, and are preferably used from the viewpoints of suppressing the feeling of tightness due to insufficient moisturization and detergency when the pH is, for example, 5 to 6.

[0024] Furthermore, among these, from the viewpoints of detergency and / or reducing skin irritation, etc., preferably N-acylglutamic acid and N-acylaspartic acid having a saturated or unsaturated acyl group of prime numbers 8 to 24, and fatty acid amidosulfonic acid having 8 to 22 carbon atoms and salts thereof can be mentioned. More preferably, cocoylglutamic acid, N-lauroylaspartic acid, cocoylmethyltaurine and salts thereof can be mentioned. Even more preferably, triethanolamine cocoylglutamic acid, sodium N-lauroylaspartic acid, sodium cocoylmethyltaurine can be mentioned.

[0025] These anionic surfactants may be used alone or in combination of two or more.

[0026] Nonionic surfactants are preferably used from the viewpoints of detergency and reduction of skin irritation when the pH of the liquid composition for skin cleansing of the present invention is, for example, 5 to 8, preferably 5 to 6. Examples of the nonionic surfactants used in the present invention include surfactants such as ester type, ether type, ester-ether type, alkanolamide type, alkyl glycoside type, and alcohol type.

[0027] Specific examples of the ester type surfactant include mono- or diesters of glycerin and saturated or unsaturated fatty acids having 8 to 20 carbon atoms such as glycol dilaurate, glycol monostearate, glycol distearate, glyceryl monolaurate, glyceryl dilaurate, glyceryl monostearate, and glyceryl distearate; sorbitan fatty acid esters; sucrose fatty acid esters and the like.

[0028] Specific examples of the ether type surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene polyoxypropylene glycol and the like.

[0029] Examples of ester-ether type surfactants include polyoxyethylene hydrogenated castor oil, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene hexitane fatty acid ester, sorbitan fatty acid ester polyethylene glycol, and others.

[0030] Examples of alkanolamide-type surfactants include cocamide DEA (coconut oil fatty acid diethanolamide), lauric acid diethanolamide, oleic acid diethanolamide, and stearate diethanolamide.

[0031] Examples of alkyl glycoside-type surfactants include octyl glucoside, decyl glucoside, and lauryl glucoside.

[0032] Examples of alcohol-type surfactants include cetanol, stearyl alcohol, and oleyl alcohol.

[0033] Among these nonionic surfactants, from the viewpoint of obtaining better skin irritation reduction and cleansing power, ester-ether type surfactants and alkanolamide type surfactants are preferred, more preferably polyoxyethylene hydrogenated castor oil and cocamide DEA are preferred, and even more preferably polyoxyethylene hydrogenated castor oil is preferred.

[0034] These nonionic surfactants may be used individually or in combination of two or more. They can be used together.

[0035] Examples of amphoteric surfactants used in the present invention include alkyl betaine type, fatty acid amidopropyl betaine type, and amine oxide type surfactants.

[0036] Examples of alkylbetaine-type surfactants include lauryldimethylaminoacetic acid betaine, stearyldimethylaminoacetic acid betaine, and octadecylaminomethyldimethylsulfopropyl betaine.

[0037] Examples of fatty acid amidopropyl betaine-type amphoteric surfactants include amidobetaines (amino acid-based amphoteric surfactants) such as cocamidopropyl betaine, and sulfobetaines such as cocamidopropyl hydroxysultaine.

[0038] Examples of amine oxide-type amphoteric surfactants include lauryldimethylamine N-oxide and oleyldimethylamine N-oxide.

[0039] These amphoteric surfactants may also be in the form of salts, for example, alkali metal salts such as sodium salts and potassium salts; triethanolamine (TEA) salts; ammonium salts, etc.

[0040] Among these amphoteric surfactants, from the viewpoint of obtaining better skin irritation reduction and cleansing power, fatty acid amidopropyl betaine type surfactants are preferred, more preferably amide betaines (amino acid-based amphoteric surfactants) such as cocamidopropyl betaine are preferred, and even more preferably cocamidopropyl betaine is preferred.

[0041] These amphoteric surfactants may be used individually or in combination of two or more.

[0042] Examples of natural surfactants used in the present invention include lecithin and lysolecithin; saponins such as quillaja saponin, soybean saponin, yucca saponin, pagoda tree saponin, beet saponin, adzuki bean saponin, carrot saponin, tea seed saponin, loofah saponin, and centella asiatica saponin.

[0043] Lecithin is a mixture of phospholipids such as phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol, and components such as triglycerides, fatty acids, and carbohydrates from vegetable oils, and is a well-known ingredient in pharmaceuticals, quasi-drugs, and cosmetics.

[0044] Lecithin may be natural lecithin derived from plants or animals (e.g., soy lecithin, egg yolk lecithin, etc.), chemically processed natural lecithin, or purified natural lecithin. Chemically processed natural lecithin includes hydrogenated lecithin obtained by hydrogenation (e.g., fully hydrogenated lecithin or partially hydrogenated lecithin) and hydroxylated lecithin obtained by hydroxylation. Purified natural lecithin includes lecithin in which the phosphatidylcholine content has been increased using a solvent such as acetone.

[0045] Examples of lysolecithins include the lyso derivatives of the above-mentioned lecithin (natural lecithin, chemically processed natural lecithin, and purified natural lecithin). Lysolecithin has a structure in which the fatty acid at the 2-position of phosphatidylcholine is removed by hydrolysis (dissolution) of lecithin with an enzyme such as phospholipase A2.

[0046] Among these natural surfactants, lecithin, lysolecithin, and saponins are preferred from the viewpoint of obtaining better skin irritation reduction and cleansing power, more preferably lecithin and lysolecithin, and even more preferably lysolecithin.

[0047] These natural surfactants may be used individually or in combination of two or more.

[0048] The content of component (A) in the liquid skin cleansing composition of the present invention is not particularly limited and can be appropriately determined according to the cleansing power to be imparted. Since the liquid skin cleansing composition of the present invention can cleanse without applying physical friction to the skin, the amount of surfactant blended in the liquid skin cleansing composition can be significantly reduced compared to the amount blended in conventional liquid skin cleansing compositions, and effective cleansing power can be achieved even with a small amount of surfactant that would not inherently exhibit effective cleansing power. From this viewpoint, the content of component (A) in the liquid skin cleansing composition of the present invention is preferably 0.025 to 2% by weight. Furthermore, from the viewpoint of further suppressing skin irritation and tightness due to insufficient moisturizing, the upper limit of the above range of content of component (A) may be 1.5% by weight or less, preferably 1% by weight or less, more preferably 0.9% by weight or less, even more preferably 0.6% by weight or less, and even more preferably 0.2% by weight or less. On the other hand, from the viewpoint of obtaining superior cleaning power, the lower limit of the above range of content of component (A) is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, even more preferably 1.5% by weight or more, and particularly preferably 1.8% by weight or more.

[0049] (B) Amphiphilic esters The liquid composition for skin cleansing of the present invention contains an amphiphilic ester as component (B). Component (B) does not exhibit a cleansing effect on its own, but when combined with component (A), it is possible to improve the cleansing power of the liquid composition for skin cleansing while maintaining low irritancy.

[0050] In the present invention, the amphiphilic ester is one that dissolves at a concentration of 2% by mass or more at room temperature in ion-exchanged water adjusted to a conductivity of 70 to 110 μs / m, as measured by the method specified in the general test methods of the Japanese Pharmacopoeia, and also dissolves at a concentration of 10% by mass or more at room temperature (25°C) in isotridecyl isononanoate (manufactured by Nisshin Oillio Group, Saracos 913), which is an oil-based agent, and ester-based surfactants are excluded.

[0051] While there are no particular limitations on the amphiphilic ester, it is preferable to select one from the group consisting of bis(polyoxyalkylene alkyl ether) dicarboxylate, dialkoxyalkyl dicarboxylate, and (eicosanedioic acid / tetradecanedioic acid) polyglyceryl-10, from the viewpoint of obtaining better skin irritation reduction and cleansing power. As the amphiphilic ester, any one of bis(polyoxyalkylene alkyl ether) dicarboxylate, dialkoxyalkyl dicarboxylate, and (eicosanedioic acid / tetradecanedioic acid) polyglyceryl-10 may be used alone, or two or more may be used in combination. Among these amphiphilic esters, bis(polyoxyalkylene alkyl ether) dicarboxylate is more preferable from the viewpoint of obtaining better skin irritation reduction and cleansing power.

[0052] The dicarboxylic acid bis(polyoxyalkylene alkyl ether) ester used in the present invention is a diester compound of a dicarboxylic acid and a polyoxyalkylene alkyl ether. Specific examples of dicarboxylic acids that constitute the diester compound of dicarboxylic acid bis(polyoxyalkylene alkyl ether) ester include, for example, oxalic acid, malonic acid, succinic acid, tartaric acid, malic acid, glutaric acid, adipic acid, pemelic acid, suberic acid, azelaic acid, sebacic acid, aspartic acid, glutamic acid, acetone dicarboxylic acid, phthalic acid, and cyclohexane-1,4-dicarboxylic acid. Furthermore, examples of polyoxyalkylene alkyl ethers that constitute the diester compound include, for example, polyoxyethylene monoalkyl ethers, and more specifically, for example, diethylene glycol monoalkyl ethers. Examples include noethyl ether and triethylene glycol monoethyl ether.

[0053] Among these dicarboxylic acid bis(polyoxyalkylene alkyl ether) esters, from the viewpoint of obtaining better skin irritation reduction and cleansing power, a diester compound of cyclohexane-1,4-dicarboxylic acid and diethylene glycol monoethyl ether is preferred, specifically, the INCI name (International Cosmetic Ingredient Dictionary and Handbook, 13th edition, Vol. 1, C Examples include compounds referred to as cyclohexane-1,4-dicarboxylic acid bisethoxydiglycol, denoted as BIS-ETHOXYDIGLYCOL CYCLOHEXANE 1,4-DICARBOXYLATE (CTFA, 2010, p.331), and diester compounds of succinic acid and diethylene glycol monoethyl ether, specifically, compounds referred to as succinic acid bisethoxydiglycol, denoted as BIS-ETHOXYDIGLYCOL SUCCINATE (INCI name: International Cosmetic Ingredient Dictionary and Handbook, 13th edition, Vol. 1, CTFA, 2010, pp.331-332), and more preferably, cyclohexane-1,4-dicarboxylic acid bisethoxydiglycol.

[0054] Furthermore, in the present invention, specific examples of the cyclohexane-1,4-dicarboxylic acid bisethoxydiglycol include, for example, "Neosolue-Aqulio (trade name)" manufactured by Nippon Seika Co., Ltd. Furthermore, specific examples of the succinate bisethoxydiglycol include, for example, "High Aquostar DCS (trade name)" manufactured by Higher Alcohol Industry Co., Ltd.

[0055] These dicarboxylate bis(polyoxyalkylene alkyl ether) esters may be used individually or in combination of two or more.

[0056] The dialkoxyalkyl dicarboxylic acid ester used in the present invention is a diester compound of a dicarboxylic acid and an alkoxy alcohol. Specific examples of dicarboxylic acids that constitute the diester compound of dialkoxyalkyl dicarboxylic acid include, for example, oxalic acid, malonic acid, succinic acid, tartaric acid, malic acid, glutaric acid, adipic acid, pemelic acid, suberic acid, azelaic acid, sebacic acid, aspartic acid, glutamic acid, acetonedicarboxylic acid, phthalic acid, and cyclohexane-1,4-dicarboxylic acid. Examples of alkoxy alcohols that constitute the diester compound include, for example, 2-methoxyethanol and 2-ethoxyethanol.

[0057] Among these dialkoxyalkyl dicarboxylates, from the viewpoint of obtaining the effects of the present invention more favorably, diester compounds of succinic acid and 2-ethoxyethanol, specifically diethoxyethyl succinate, are preferred.

[0058] These dialkoxyalkyl dicarboxylates may be used individually or in combination of two or more.

[0059] The (eicosanedioic acid / tetradecanediic acid) polyglyceryl-10 used in the present invention is not particularly limited, but examples include "Neosolue-Aqua" (trade name) and "Neosolue-AquaS" (trade name) manufactured by Nippon Seika Co., Ltd.

[0060] The content of component (B) in the liquid composition for skin cleansing of the present invention is not particularly limited, but for example, it may be 0.1% by weight or more. From the viewpoint of obtaining even better cleansing power and / or further reducing the feeling of tightness due to insufficient moisturizing, the content of component (B) is preferably 0.5% by weight or more, more preferably 1.5% by weight or more, and more preferably 2% by weight. Examples include amounts of % by weight or more. (B) There is no particular upper limit to the range of the content of component, but from the viewpoint of the stability of the skin cleansing spray, for example, 5% by weight or less, preferably 4% by weight or less, and more preferably 3% by weight or less.

[0061] In the liquid composition for skin cleansing of the present invention, the ratio of component (A) to component (B) is not particularly limited and is determined by the above-mentioned content of each component. However, from the viewpoint of obtaining better reduction of skin irritation and cleansing power, for example, component (B) is 0.1 to 100 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, and even more preferably 1 to 5 parts by weight per 1 part by weight of component (A).

[0062] Other ingredients In addition to the components mentioned above, the liquid composition for skin cleansing of the present invention may also contain other bases and additives necessary for formulation, etc., to the extent that they do not impair the effects of the present invention. Such additives are not particularly limited as long as they are pharmaceutically acceptable, but examples include aqueous bases such as water, lower alcohols having 1 to 5 carbon atoms (ethanol, isopropanol, etc.), and polyhydric alcohols (ethylene glycol, 1,3-butylene glycol (1,3-BG), propylene glycol, isoprene glycol, diethylene glycol, dipropylene glycol, polypropylene glycol, glycerin, etc.); preservatives (phenoxyethanol, methylparaben, propylparaben, benzoic acid, sodium benzoate, sorbic acid, etc.), flavoring agents (citral, 1,8-cineole, citronellal, farnesol, etc.), colorants (tar dyes (Brown 201, Blue 201, Yellow 4, Yellow 403, etc.), cocoa pigment, chlorophyll, aluminum oxide, etc.), and viscosity modifiers (hydroxypropylcellulose, hydroxyethylcellulose, cross-linked acrylic acid polymer, carboxyvinyl polymer, hypromellose, polyvinylpyrrolidone, sodium alginate). Examples of pH adjusters include phosphoric acid, ethylcellulose, sodium carboxymethylcellulose, xanthan gum, carrageenan, etc., and preferably citric acid and potassium hydroxide.Additives include ), humectants (dl-pyrrolidone carboxylate sodium solution, D-sorbitol solution, macrogol, etc.), stabilizers (dibutylhydroxytoluene, butylhydroxyanisole, sodium edetate, sodium metaphosphate, L-arginine, L-aspartic acid, DL-alanine, glycine, sodium erythorbate, propyl gallate, sodium sulfite, sulfur dioxide, chlorogenic acid, catechin, rosemary extract, etc.), antioxidants, UV absorbers, chelating agents, adhesives, buffers, solubilizers, preservatives, etc. These base materials and additives may be used individually or in combination of two or more. The content of these base materials and additives can be appropriately set depending on the formulation form, etc.

[0063] In addition to the components described above, the liquid composition for skin cleansing of the present invention may optionally contain other pharmacological components, provided that they do not impair the effects of the present invention. Examples of such pharmacological components include vitamins (vitamins A, B1, B2, B5, B6, B12, C, D, K, niacin, folic acid, biotin, lycopene, etc.), antihistamines (diphenhydramine, diphenhydramine hydrochloride, etc.), and local anesthetics (procaine, tetracaine, bupipacaine, mepi). Examples of pharmacological components include pacaine, chloroprocaine, propalacaine, meprilcaine or salts thereof, orthocaine, oxethazaine, oxypolyentoxydecane, belladonna extract, percaminate, tesitdecitin, etc.), anti-inflammatory agents (indomethacin, felbinac, diclofenac sodium, loxoprofen sodium, etc.), skin protectants (collodion, castor oil, etc.), blood circulation promoting components (nonyl vanillylamide, benzyl nicotinate, capsaicin, chili pepper extract, etc.), cooling agents (menthol, camphor, borneol, peppermint water, peppermint oil, etc.), and mucopolysaccharides (chondroitin sulfate sodium, glucosamine, hyaluronic acid, cationized hyaluronic acid (dihydroxypropyltrimonium hyaluronate, etc.)). These pharmacological components may be used individually or in combination of two or more. When including these pharmacological components, the amount should be set appropriately according to the type of pharmacological component used, the expected effect, etc.

[0064] pH The pH of the liquid skin cleansing composition of the present invention is adjusted to 3 to 8 from the viewpoint of reducing skin irritation and achieving cleansing power. The preferred pH of the liquid skin cleansing composition of the present invention may vary depending on the type of component (A), but for example, when a carboxylic acid-type amino acid-based anionic surfactant and / or a sulfonic acid-type amino acid-based anionic surfactant is used as component (A), a preferred pH is 3 to 6, more preferably 3 to 5, from the viewpoint of suppressing tightness due to insufficient moisturizing, or from the viewpoint of suppressing tightness due to insufficient moisturizing and cleansing power, and even more preferably 3 to 4, from the viewpoint of suppressing tightness due to insufficient moisturizing and cleansing power; when a nonionic surfactant is used as component (A), a preferred pH is 5 to 8, more preferably 5 to 6, from the viewpoint of cleansing power and reducing skin irritation. In the present invention, pH refers to the pH at 25°C.

[0065] form The liquid composition for skin cleansing of the present invention is in liquid or gel form at room temperature. The viscosity of the liquid composition for skin cleansing of the present invention is 10,000 mPa·s or less, preferably 5,000 mPa·s or less, at 20°C. The viscosity is measured using a BL viscometer (rotor No. 3, 6 rpm, 20°C).

[0066] container The container for containing the liquid composition for skin cleansing of the present invention is not particularly limited as long as it allows the liquid composition to be applied directly to the skin from within the container. Examples include spray containers, pouring or dropping containers (especially wash bottles), and from the viewpoint of ease of use in beauty salons and hair salons, pouring or dropping containers (especially wash bottles) are preferred. The spray containers in this invention dispense the contents in a mist state and are different from pump foamer containers that dispense liquid compositions for skin cleansing in a foam state.

[0067] In this invention, by housing the skin cleansing liquid composition in a spray container, a pouring or dropping container (particularly a wash bottle), the skin cleansing liquid composition is applied directly to the skin without foaming before application. Therefore, application to the skin is easy, and physical friction from hands during application and / or physical friction from foam during washing can be avoided. Examples of spray containers include non-aerosol spray containers such as pump-type spray containers and aerosol spray containers. Examples of nozzle diameters (inner diameter of nozzles) for spray containers include 0.01 to 3 mmφ, preferably 0.1 to 1 mmφ. Examples of spray amounts per push when the spray container is a pump-type spray container include 0.05 to 1.2 g, preferably 0.1 to 0.3 g.

[0068] Purpose The liquid skin cleansing composition of the present invention is used to remove bodily fluids and dirt such as oils, sweat, etc. from the skin, and is not intended for use as a makeup remover (cleansing agent). The liquid skin cleansing composition of the present invention is used for facial cleansing treatments in beauty salons and hair salons. The liquid skin cleansing composition of the present invention is used by applying it directly to the skin without diluting it with water or lathering it. The amount to be used per application depends on the concentration of the surfactant and the degree of dirt, but for example, when used for facial cleansing, it is 0.5 to 3 g, preferably 1 to 2 g.

[0069] More specifically, the skin cleansing liquid composition can be applied directly to the area to be cleaned from a spray container, pouring or dropping container (especially a wash bottle) without having to take it in your hands. By applying the skin cleansing liquid composition directly to the area to be cleaned in this way, it becomes possible to cleanse using only the mechanical force of the liquid flow, without any physical friction such as friction between the skin of the area to be cleaned and the hand, or friction between the skin of the area to be cleaned and air bubbles. Since the skin cleansing liquid composition of the present invention has an excellent cleansing power, by cleaning using the mechanical force of the liquid flow without applying physical friction in this way, the burden on the skin during cleansing is significantly reduced, making it possible to perform an extremely gentle cleansing method. This foam-free cleansing method allows for quick cleansing, and the fact that it contains fewer surfactants and is gentle on the skin is easily noticeable, making it easier to satisfy consumers who are highly conscious of pursuing gentle cleansing.

[0070] The liquid skin cleansing composition of the present invention can be used to cleanse any part of the body and is not particularly limited; examples include hands, hair, scalp, body, and face. Furthermore, because the liquid skin cleansing composition of the present invention can exhibit excellent cleansing power without causing physical friction to the skin, it is suitable for use on the face, which is sensitive to irritation. Moreover, because the liquid skin cleansing composition of the present invention is low-irritant and has excellent cleansing power, it is particularly preferable to use it on sensitive skin. Sensitive skin refers to skin that reacts hypersensitively to specific components of topical agents (e.g., surfactants, preservatives, fragrances, etc.) or ultraviolet rays, either chronically or temporarily. A preferred example of sensitive skin to which the liquid skin cleansing composition of the present invention is applied is skin that is chronically or temporarily sensitive enough to feel irritation when a liquid skin cleansing composition containing component (A) and not containing component (B) is applied. In particular, skin that is chronically or temporarily sensitive enough to feel irritation when a liquid skin cleansing composition containing, for example, 0.025 to 2% by weight of component (A) and not containing component (B), and adjusted to a pH of 3 to 8, is applied is a prime example.

[0071] After washing, the skin cleansing liquid composition can be rinsed off with water. Even when rinsing with water, the mechanical force of the water flow should be used to rinse away the water without applying physical friction by hand. The water used for rinsing can also be contained in a spray container, a pouring or dripping container (especially a wash bottle), preferably a pouring or dripping container (especially a wash bottle), and applied to the area to be cleaned in the same way as the skin cleansing liquid composition.

[0072] Furthermore, since the surfactant concentration of the skin cleansing liquid composition of the present invention can be extremely low, it is not necessary to rinse it off after washing. For this reason, the skin cleansing liquid composition of the present invention is suitable for use in wiping in hospitals, skin cleansing treatments such as facial washing in beauty salons and hair salons, and disaster relief supplies. If rinsing is not performed, the remaining skin cleansing liquid composition on the cleansed area may be absorbed and removed using an absorbent material such as a towel or tissue without rubbing.

[0073] Manufacturing method The liquid composition for skin cleansing of the present invention is manufactured by mixing the aforementioned components (A) and (B), as well as other components that may be added as needed, to prepare it to have a predetermined form and pH.

[0074] 2. Skin cleansing method As described above, amphiphilic esters can improve the cleansing power of a skin cleansing composition containing a surfactant and having a pH of 3 to 8 without applying physical friction to the skin. Therefore, the present invention further provides a skin cleansing method comprising applying a liquid skin cleansing composition, having a pH of 3 to 8 and containing an amphiphilic ester as component (B) together with a surfactant as component (A), to the skin without applying physical friction to the skin. The skin cleansing method of the present invention can be performed as a cleansing treatment in beauty salons and hair salons.

[0075] In the aforementioned skin cleansing method, the types and amounts of ingredients used, the form of the skin cleansing composition, etc., are as shown in the "1. Liquid Composition for Skin Cleansing" section above. [Examples]

[0076] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0077] [Example of a sample exam] Liquid skin cleansing compositions were prepared with the compositions shown in Tables 1 to 4. Details of each component shown in Tables 1 to 4 are as follows. The liquid skin cleansing compositions shown in Tables 1 to 4 were all liquids, and their viscosity at 20°C (measured using a BL viscometer (Brookfield B-type viscometer), rotor No. 3, 6 rpm) was in the range of 5000 mPa·s or less. Furthermore, with the exception of Reference Example 1 (pH at 25°C was approximately 10), the pH at 25°C was in the range of 3 to 8. • Sodium laurate (manufactured by NOF Corporation, "Nonsal LN-1" (product name)) • Cocoyl glutamate TEA (Ajinomoto Co., Inc.'s "Amisoft CT-12S (product name)") • Sodium cocoyl methyl taurate (manufactured by NOF Corporation as "Diapon K-SF (product name)") • Sodium N-lauroyl aspartate solution (20% by weight) (Asahi Kasei Fine Chemicals Corporation's "Aminoformer FLDS-L (product name)") • Polyoxyethylene lauryl ether acetate (Kao Corporation's "Kao Akipo RLM-45 (product name)") • Cocamide DEA (Amizol CDE-G (product name) manufactured by Kawaken Fine Chemical Co., Ltd.) • PEG-60 Hydrogenated Castor Oil (Polyoxyethylene Hydrogenated Castor Oil; manufactured by Nikko Chemicals Co., Ltd., "NIKKOL HCO-60 (product name)") • Polyoxyethylene sorbitan monostearate (manufactured by Kao Corporation, Leodor TW-S120V) Glycerin mono-2-ethylhexyl ether (SEPPIC "sensiva") SC 50 JP (product name)”) • Cocamidopropyl betaine ("Softazoline CPB (product name)" manufactured by Kawaken Fine Chemical Co., Ltd.) • Lauryl hydroxysulfobetaine solution (30% by weight) (Kao Corporation's "Anhitoll 20HD (product name)") • Lysolecithin (manufactured by Kyowa Hakko Bio Co., Ltd., "Lysolecithin Kyowa (product name)") • Quillaja extract (Maruzen Pharmaceutical Co., Ltd. "Quillaja extract BG", saponin content 5% by weight) • Cyclohexane-1,4-dicarboxylic acid bisethoxydiglycol (manufactured by Nippon Seika Co., Ltd. as "Neosolue-Aqulio (product name)") • Bisethoxydiglycol succinate (manufactured by Higher Alcohol Industry Co., Ltd., "High Aquostar DCS (product name)")

[0078] <Evaluation of cleaning power> Ten cosmetic evaluation panelists evaluated the cleansing power of the prepared liquid skin cleansing compositions. The following was conducted. Specifically, each skin cleansing liquid composition was placed in a pump-type spray container (Takemoto Container Co., Ltd. "Z-155-C110 (product name)", with a spray volume of 0.15g per pump), and 1.5g was applied by spraying it directly onto the face. After leaving it on for about 5 seconds, the face was rinsed with water without touching it with the hands. After dabbing the face with a towel to absorb the water, the degree to which dirt was removed from the skin was scored by sensory evaluation based on the following indicators.

[0079] 5 points: I felt that it removed stains very well. 4 points: I felt that it removed stains effectively. 3 points: Neither 2 points: I don't feel that it removes dirt very well. 1 point: I don't feel any effect at all in removing stains.

[0080] The scores obtained by the 10 panelists were totaled, and the degree of cleaning power was evaluated according to the following classification. The results are shown in Tables 1 to 4. ◎: 45 points or higher ○: 40 points or more, but less than 45 points △: 35 points or more, but less than 40 points ×: Less than 35 points

[0081] <Evaluation of tension> Ten cosmetic evaluation panelists evaluated the tightness sensation of the prepared liquid skin cleansing compositions. Specifically, each liquid skin cleansing composition was placed in a pump-type spray container (Takemoto Container Co., Ltd. "Z-155-C110 (product name)" (dispense volume per pump is 0.15g)), and 1.5g was applied by spraying it directly onto the face. After leaving it on for about 5 seconds, it was rinsed off with water without touching the face with hands. After dabbing the face with a towel to absorb the water, the tightness sensation immediately after washing was scored by sensory evaluation based on the following indicators. A stronger tightness sensation indicates insufficient moisturizing.

[0082] 5 points: I don't feel any tightness at all. 4 points: I hardly feel any tightness. 3 points: I feel very little tightness. 2 points: I feel a tightness. 1 point: I feel a strong sense of tightness.

[0083] The scores obtained by the 10 panelists were totaled, and the degree of tightness was evaluated according to the following classification. The results are shown in Tables 3 and 4. ◎: 45 points or higher ○: 40 points or more, but less than 45 points △: 35 points or more, but less than 40 points ×: Less than 35 points

[0084] <Cultured Epidermal Skin Irritation Test (In vitro Evaluation of Skin Irritation)> The prepared liquid composition for skin cleansing was subjected to a cultured epidermal skin irritation test as follows. 1. Preparation of the cultured epidermal model LabCyte EPI-MODEL24 The assay medium was warmed and 0.5 mL was added to each 24-well assay plate. The cultured epidermal model LabCyte EPI-MODEL24 (lot number: LCE24-180226-A) was transferred to the 24-well assay plate to which the assay medium had been added. After confirming that there were no air bubbles at the bottom of the culture cup, it was placed in a CO2 incubator and left to stand for at least 1 hour before exposure to the test substance.

[0085] 2. Application and cleaning of the test substance Of the 24 epidermal models, 12 were used (the remaining models underwent pre-culturing until the main test). The 24-well assay plate was removed from the CO2 incubator. The assay medium was warmed and 1.0 mL was added to each of the third rows of the 24-well assay plate. 25 μL of the test substance (each skin cleansing liquid composition) was dropped onto the cultured epidermis in the culture cup without using a pump-type spray container, and the surface was exposed to the test substance. At 1, 5, and 10 minutes after exposure, the test substance was aspirated and removed, the cultured epidermal model in the cup was washed with phosphate-buffered water (PBS), and transferred to the third row of the 24-well assay plate.

[0086] 3. MTT Exam The MTT test is a method for measuring the viability of cells by extracting a formazan dye, which is produced when MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] taken up into cells is reduced by mitochondrial dehydrogenases within the cell, using an organic solvent, and measuring the absorbance at 570 nm.

[0087] 10 mL of MTT medium was prepared at a final concentration of 0.5 mg / mL. The MTT medium was warmed and 0.5 mL was added to each of the 4th rows of a 24-well assay plate. The cultured epidermal model was transferred to the 4th row of the 24-well assay plate and placed in a CO2 incubator for 3 hours to perform the MTT reaction. After the MTT reaction was complete, the cultured skin was removed with tweezers and transferred to a 1.5 mL microtube. 300 μL of isopropanol was added to the microtube and the cultured epidermal model was completely immersed. After standing for 2 hours, the microtube was vortexed to extract the pigment. The extract (200 mL) was added to each well of a 96-well plate. In addition, 200 μL of isopropanol was added to A1 as a blank (negative control). The absorbance at 570 nm and 650 nm was measured using a microplate reader. The value obtained by subtracting the absorbance at 650 nm from the absorbance at 570 nm was used as the measurement value, and the viability of the test substance was calculated using the following formula.

[0088] [Math 1]

[0089] The viable cell rate was classified based on the following criteria, and skin irritation was evaluated. The results are shown in Tables 3 and 4. ◎: 90% or more ○: 75% or more and less than 90% △: 65% or more but less than 75% ×: 50% or more but less than 65% ××: Less than 50%

[0090] As shown in Tables 1-4, no cleansing power was observed in liquid skin cleansing compositions containing surfactants alone at a concentration of 0.025-2% by weight (Reference Comparative Examples 1-10). In contrast, in liquid skin cleansing compositions containing amphiphilic esters (Reference Comparative Examples 11-15), which do not exhibit cleansing power on their own, together with 0.025-2% by weight of surfactants (Reference Examples 1-20), excellent cleansing power was obtained simply by applying the mixture directly to the skin by spraying from a spray container, without any physical friction, and solely by utilizing the mechanical force of the liquid flow. In other words, it was demonstrated that gentle cleansing is possible.

[0091] Furthermore, as shown in Reference Examples 1-3, liquid skin cleansing compositions containing more than 2% by weight of a surfactant alone also provide excellent cleansing power simply by applying them directly to the skin by spraying. On the other hand, considering the skin irritation caused by the surfactant concentrations shown in Reference Examples 1-3, reducing the surfactant concentration to 2% by weight or less, as shown in Reference Examples 9-20, resulted in not only excellent cleansing power but also superior low irritation. In other words, it has been shown that by setting the surfactant concentration of a liquid skin cleansing composition applied to a cleansing method that involves direct application to the skin by spraying to 0.025-2% by weight, it is possible to achieve cleansing that is gentle on the skin both physically and chemically.

[0092] [Table 1]

[0093] [Table 2]

[0094] [Table 3]

[0095] [Table 4]

[0096] [Example Test] Liquid compositions for skin cleansing having the compositions shown in Tables 5-6 were prepared. The details of each component shown in Tables 5-6 are as shown in the reference test examples. The liquid compositions for skin cleansing shown in Tables 5-6 were liquids, and their viscosities at 20 °C (measured with a BL viscometer (Brookfield B-type viscometer), rotor No. 3, 6 rpm) were all in the range of 5000 mPa·s or less.

[0097] <pH Measurement> For the prepared skin cleansing agent compositions, the pH at 25 °C was measured using a desktop pH meter (F-72) manufactured by HORIBA.

[0098] <Cleansing Power Evaluation> For the prepared skin cleansing agent compositions, the degree of cleansing power was evaluated in the same manner as in the reference test examples. The results are shown in Tables 5-6.

[0099] <Stimulation Evaluation> For the prepared skin cleansing agent compositions, 10 professional cosmetic evaluation panelists conducted stimulation evaluations. Specifically, each skin cleansing agent composition was contained in a pump-type spray container ("Z-155-C110 (trade name)" manufactured by Takemoto Container Co., Ltd., injection amount per push: 0.15 g), and 1.5 g was applied by directly spraying it all over the body. After leaving it for about 5 seconds, it was then rinsed off with water so that the hands did not touch the skin. After pressing the skin with a towel to absorb the water, the stimulation was scored by conducting a sensory evaluation based on the following criteria.

[0100] 5 points: No stimulation was felt at all 4 points: Little stimulation was felt 3 points: A slight stimulation was felt 2 points: Stimulation was felt 1 point: A strong stimulation was felt

[0101] The total scores obtained by the 10 panelists were summed up, and the degree of stimulation was evaluated according to the following classification. The results are shown in Tables 5-6. ◎: 45 points or more ○: 40 points or more and less than 45 points △: 35 points or more and less than 40 points ×: Less than 35 points

[0102] <Evaluation of tension> The degree of tightness was evaluated in the same manner as in the reference test example, except that the evaluation of tightness was also performed 5 minutes and 10 minutes after washing, in addition to immediately after washing. The results are shown in Tables 5 and 6.

[0103] As shown in Tables 5-6, in liquid skin cleansing compositions (Examples 1-15) containing 2% by weight of surfactant and an amphiphilic ester, and with a pH adjusted to 3-8, it was found that even with a low concentration of surfactant, excellent cleansing power could be obtained simply by applying the mixture directly to the skin by spraying from a spray container, without any physical friction, and solely by utilizing the mechanical force of the liquid flow. However, in liquid skin cleansing compositions (Comparative Examples 1-5) containing 2% by weight of surfactant and an amphiphilic ester, the pH was below 3, resulting in increased irritation, and depending on the type of surfactant, a decrease in cleansing power and an increased feeling of tightness due to insufficient moisturizing were observed. In liquid skin cleansing compositions (Comparative Examples 6-10) with a pH above 8, the feeling of tightness due to insufficient moisturizing was increased, and depending on the type of surfactant, increased irritation and a decrease in cleansing power were observed.

[0104] [Table 5]

[0105] [Table 6]

Claims

1. A liquid skin cleansing composition comprising (A) a surfactant and (B) an amphiphilic ester, having a pH of 3 to 8, and used for cleansing the skin without applying physical friction to the skin.

2. 2. The liquid skin cleansing composition according to claim 1, wherein the component (B) is selected from the group consisting of dicarboxylic acid bis(polyoxyalkylene alkyl ether) esters, dicarboxylic acid dialkoxyalkyl esters, and polyglyceryl-10 (eicosanedioate / tetradecanedioate).

3. 3. The liquid composition for cleansing skin according to claim 2, wherein the dicarboxylic acid bis(polyoxyalkylene alkyl ether) ester is cyclohexane-1,4-dicarboxylic acid bisethoxydiglycol.

4. 4. The liquid composition for cleansing skin according to claim 1, wherein the content of component (A) is 0.025 to 2% by weight.

5. 5. The liquid skin cleansing composition according to claim 1, which is applied to sensitive skin.

6. A method for cleansing skin, comprising applying a liquid skin cleansing composition containing (A) a surfactant and (B) an amphiphilic ester and having a pH of 3 to 8 to the skin without subjecting the skin to physical friction.