External composition

Abstract

To provide a fluid external composition having superior stability and pleasant feeling upon use.SOLUTION: Provided is a fluid external composition comprising: (A) inorganic salt particles; (B) nanofibers; and (C) an amphoteric surfactant or (D) an anionic surfactant.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an external composition. More specifically, the present invention relates to a fluid external composition containing inorganic salt particles, nanofibers, and an amphoteric surfactant or an anionic surfactant.

Background Art

[0002] Conventionally, external compositions containing scrub particles in skin cleansers have been widely used as body and scalp cleansers. In addition to the dirt removal effect by ordinary cleaning components, the external composition has an effect of removing old keratin and dirt in pores, a massage effect, and an effect of making the skin softer and better by rubbing the scrub particles against the skin. Inorganic salts are widely used as scrub particles from the viewpoints of price and safety. When an inorganic salt is blended as a scrub particle, it is necessary to blend the inorganic salt in an amount more than the saturation amount and precipitate it from an external composition such as a cleanser. However, since inorganic salts can destroy thickeners and the emulsified state, there is a possibility of separation of the external composition itself and precipitation of other components contained in the external composition. Therefore, it has not been easy to produce an external composition having excellent stability in a saturated state of the inorganic salt. In Patent Document 1, it is shown that by combining sodium chloride, aloe juice, and a surfactant, the stability of the salt fluid is excellent and the elongation on the skin is improved. Further, in Patent Document 2, it is shown that the usability is improved by combining sodium chloride, urea, and an ionic surfactant. In Patent Document 3, it is shown that a stable dispersion can be obtained by combining carboxymethylated cellulose nanofibers, carboxymethylated cellulose having no crystallinity of cellulose type I, and an inorganic salt (not a scrub particle). However, the above composition has not achieved a high level of compatibility between stability and good usability while blending an inorganic salt as a scrub particle.

Prior Art Documents

Patent Documents

[0003] Patent Document 1 Japanese Patent Application Laid-Open No. 2006-76999 Patent Document 2 Japanese Patent Application Laid-Open No. 2002-105488 Patent Document 3 Japanese Patent Application Laid-Open No. 2021-147595 Summary of the Invention Problems to be Solved by the Invention

[0004] The present invention has been devised to improve the above problems, and an object thereof is to provide an external composition containing inorganic salt particles as scrub particles, having excellent stability, and good usability. Means for Solving the Problems

[0005] As a result of intensive studies, the present inventors have found that by blending inorganic salt particles and nanofibers and further blending a specific surfactant, it is possible to provide an external composition having excellent stability, easy to spread, and excellent usability. Aspects of the present invention may be as follows. [1] A fluid external composition containing (A) inorganic salt particles, (B) nanofibers, (C) an amphoteric surfactant or (D) an anionic surfactant. [2] The fluid external composition according to [1] above, containing both (C) an amphoteric surfactant and (D) an anionic surfactant. [3] The fluid external composition according to [1] or [2] above, wherein the inorganic salt is sodium chloride and / or magnesium chloride. [4] The fluid external composition according to [1] or [2] above, wherein (B) the nanofiber is a cellulose nanofiber. [5] The fluid external composition according to [1] or [2] above, containing component (C), and component (C) being coconut fatty acid amide propyl betaine or sodium cocoamphoacetate. [6] The fluid external composition according to [1] or [2] above, which contains component (D) and component (D) is sodium tetradecene sulfonate or sodium lauroyl methyl taurine. [7] The fluid external composition according to [1] or [2] above, wherein the content of component (B) is 0.1 to 10% by mass based on the total amount of the fluid external composition. [8] The fluid external composition according to [1] or [2] above, wherein the content of component (A) is 1 to 90% by mass based on the total amount of the fluid external composition. [9] The fluid external composition according to [1] or [2] above, wherein the viscosity of the fluid external composition measured by a rotational viscometer is 100,000 mPa·s or less.

[10] A skin cleanser containing the fluid external composition according to [1] or [2] above. [Advantages of the Invention]

[0006] The present invention provides an external composition that is excellent in stability, easy to spread, and has an excellent feel in use by blending inorganic salt particles and nanofibers and a specific surfactant. [Modes for Carrying Out the Invention]

[0007] Here, the modes for carrying out the invention will be described in detail. However, the preferred modes, more preferred modes, etc. exemplified below can be used in appropriate combinations with each other regardless of expressions such as "preferred" and "more preferred". In addition, the description of the numerical range is illustrative, and ranges appropriately combined with the upper and lower limits of each range and the numerical values of the examples can also be preferably used. Furthermore, terms such as "containing" or "including" may be read as "consisting essentially of" or "consisting only of".

[0008] [Fluid External Composition] A fluid external composition which is one aspect of the present invention contains (A) inorganic salt particles, (B) nanofibers, (C) an amphoteric surfactant and / or (D) an anionic surfactant, and is a fluid external composition. Hereinafter, each will be specifically described.

[0009] (A) Inorganic salt particles The inorganic salt particles used here are those that can remove skin dirt and old keratin in the composition of the present invention and can provide a massage effect. Such inorganic salt particles are generally sometimes called scrub or scrub particles. As the inorganic salt, as long as it can be in a particulate form, any known inorganic salt can be used. For example, hydrochlorides, sulfates, nitrates, carbonates, silicates, phosphates, thiosulfates, etc. can be mentioned. As the salts, for example, alkali metal salts such as sodium and potassium; alkaline earth metal salts such as magnesium and calcium can be mentioned. Preferably, sodium chloride, sodium sulfate, sodium nitrate, sodium carbonate, sodium hydrogen carbonate, sodium silicate, sodium phosphate, sodium hydrogen phosphate, sodium metaphosphate, sodium polyphosphate, sodium thiosulfate, potassium chloride, potassium sulfate, potassium aluminum sulfate, potassium nitrate, potassium carbonate, magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium carbonate, magnesium silicate, calcium carbonate, calcium silicate, calcium phosphate, calcium hydrogen phosphate, and more preferably sodium chloride or magnesium chloride. Component (A) may be used alone or in combination of two or more. The particle size of the inorganic salt particles is preferably such that the particle size measured by the sieving method is, for example, 0.01 mm to 3 mm, more preferably 0.05 to 2 mm, and still more preferably 0.1 mm to 1 mm. If the particle size of the inorganic salt particles is 0.01 mm or more, it will not dissolve immediately on the skin wetted with water or hot water, and a sufficient massage effect can be provided. If the particle size of the inorganic salt particles is 3 mm or less, there will be no feeling of roughness during use, and it will not damage the skin, which is preferable.

[0010] The content of the above component (A) is, for example, 1 to 90% by mass, preferably 3 to 80% by mass, more preferably 10 to 75% by mass, and still more preferably 25 to 70% by mass with respect to the total mass of the above-mentioned external-use composition with fluidity. By setting the content of component (A) within this range, sufficient effects can be exerted. In particular, when the external-use composition with fluidity contains a solvent, it is preferable that the amount of the inorganic salt is formulated to be more than the saturation amount with respect to the solvent. By formulating the inorganic salt in an amount more than the saturation amount of the solvent, inorganic particles precipitate from the external-use composition with fluidity, and an effect as good scrub particles can be obtained. For example, when the inorganic salt particles are sodium chloride and the solvent is water, it is appropriate to contain sodium chloride in an amount exceeding the solubility of sodium chloride in water at normal temperature (25°C ± 5°C), which is 35.92 g / 100 g of water, more preferably in an amount exceeding 40 g / 100 g of water, and still more preferably in an amount exceeding 50 g / 100 g of water.

[0011] (B) Nanofibers The nanofibers used here exert an effect in improving the dispersibility of component (A) and preventing the precipitation of component (A) in the composition of the present invention. Examples of the nanofibers include those derived from natural raw materials such as cellulose, chitin, and silk, and those derived from synthetic raw materials such as glass and synthetic resins. For example, cellulose nanofibers (also called CNF) made from cellulose as a raw material are preferably used. Examples of the raw materials for cellulose nanofibers include wood, bamboo, rice straw, wheat straw, rice husks, vegetable residues, tea husks, orange peels, and herbs such as pampas grass, and seaweeds. The nanofibers are more preferably an aggregate of refined fibers and have a two-dimensional or three-dimensional network structure. Component (B) may be used alone or in combination of two or more.

[0012] The average length of the nanofibers is, for example, from 0.0001 to 100 μm, preferably from 0.001 to 80 μm, more preferably from 0.05 to 50 μm, and even more preferably about 0.1 to 10 μm. The average fiber diameter is, for example, from 0.1 to 1000 nm, preferably from 0.2 to 500 nm, more preferably from 0.5 to 300 nm, and even more preferably about 1 to 100 nm. The average fiber diameter is measured visually using a scanning electron microscope, and in a microscopic image where the nanofibers can be confirmed, 100 or more cellulose fibers are extracted, and the average fiber diameter is calculated from their fiber heights. The average length of the nanofibers is calculated from the distance in the fiber direction. The ratio of the average length of the nanofibers to the average fiber diameter (aspect ratio = average length / average fiber diameter) is, for example, 10 or more, preferably 30 or more, more preferably 50 or more, and even more preferably 100 or more, and the upper limit of the aspect ratio is at most 10000 or less, preferably 1000 or less.

[0013] The content of the component (B) is, for example, 0.1 to 10% by mass, preferably 0.2 to 8% by mass, more preferably 0.3 to 5% by mass, based on the mass of the entire fluidity external composition. By setting the content of the component (B) within this range, the dispersibility of the component (A) can be improved, and the effect of preventing precipitation of the component (A) can be fully exerted.

[0014] (C) Amphoteric surfactant The amphoteric surfactant used here contributes to improving the stability and foaming property of the fluidity external composition, and can improve the usability and detergency of the fluidity external composition. Examples of the amphoteric surfactant mentioned here include betaine-type surfactants such as alkyl betaine-based and sulfobetaine-based surfactants, amine oxide-type surfactants, imidazoline-type surfactants, and glycine-type surfactants. Specifically, examples of alkyl betaine surfactants include hydroxyalkyl (C12-14) hydroxyethyl sarcosine, coconut oil fatty acid amide propyl betaine, lauramide propyl betaine, myristamide propyl betaine, palm kernel oil fatty acid amide propyl betaine, lauryl betaine, myristyl betaine, stearyl betaine, oleyl betaine, coco betaine, lauryl dimethyl carboxymethyl betaine, lauryl dimethyl alpha-carboxyethyl betaine, cetyl dimethyl carboxymethyl betaine, lauryl bis-(2-hydroxyethyl) carboxymethyl betaine, stearyl bis-(2-hydroxypropyl) carboxymethyl betaine, oleyl dimethyl gamma-carboxypropyl betaine, and lauryl bis-(2-hydroxypropyl) alpha-carboxyethyl betaine. Examples of sulfobetaine surfactants include lauramide propyl hydroxysultaine, lauryl hydroxysulfobetaine, lauric acid amide propyl hydroxysulfobetaine, coco dimethyl sulfopropyl betaine, stearyl dimethyl sulfopropyl betaine, lauryl dimethyl sulfoethyl betaine, and lauryl bis-(2-hydroxyethyl) sulfopropyl betaine. Examples of amine oxide surfactants include lauramide propyl amine oxide and lauryl dimethyl amine oxide. Examples of imidazoline surfactants include sodium coco amphoacetate, sodium coco amphodiacetate, sodium lauro amphoacetate, sodium lauro amphodiacetate, sodium coco amphopropionate, and sodium lauraminopropionate. Examples of glycine surfactants include alkyl diaminoethyl glycine hydrochloride and sodium lauryl diaminoethyl glycine. More preferably, they are coconut oil fatty acid amide propyl betaine and sodium coco amphoacetate. Component (C) may be used alone or in combination of two or more. Further, component (C) may be used together with component (D) described below or in place of component (D). When component (D) is present, component (C) may be optional.

[0015] The content of the above component (C) is, for example, 0.01 to 20% by mass, preferably 0.1 to 15% by mass, more preferably 0.2 to 10% by mass, based on the mass of the entire fluid external composition. When component (D) is also present, the content of component (C) may be adjusted so that the total amount of component (C) and component (D) is within these ranges. When both component (C) and component (D) are present, the mass ratio (C:D) of component (C) to component (D) is, for example, 1:20 to 20:1, preferably 1:10 to 10:1, more preferably 1:7 to 7:1. By setting the content of component (C) within the above range, the above-described effects can be fully exhibited.

[0016] (D) Anionic surfactant The anionic surfactant used here also contributes to improving the stability and foaming properties of the above fluid external composition, as well as contributing to improving the feel of use and detergency of the above fluid external composition, similar to the above component (D). Examples of the anionic surfactant referred to here include carboxylates containing alkyl ether acetic acid-based surfactants, amino acid-based surfactants, fatty acid-based surfactants, etc., sulfonates containing alkyl sulfate-based surfactants, etc., and sulfate esters containing POE alkyl ether sulfate-based surfactants, etc. Specifically, examples of the alkyl ether acetic acid-based surfactant include POE alkyl ether acetic acid-based surfactants such as sodium laures-4-carboxylate, sodium laures-5-carboxylate, sodium laures-6-carboxylate, and sodium tricades-4-carboxylate, and sodium lauryl glycol carboxylate. Examples of the amino acid-based surfactant include taurine-based surfactants such as sodium lauroyl methyl taurate, sodium cocoyl methyl taurate, and sodium cocoyl methyl taurine taurate, monocarboxylic acid-based surfactants such as sodium lauroyl methyl alaninate, sodium cocoyl methyl alaninate, potassium cocoyl glycinate, sodium cocoyl sarcosinate, and sodium lauroyl sarcosinate, and dicarboxylic acid-based surfactants such as sodium cocoyl glutamate and triethanolamine cocoyl glutamate. Examples of the fatty acid-based surfactant include salts of higher fatty acids such as caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, pentadecylic acid, palmitic acid, palmitoleic acid, margaric acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, arachidic acid, and behenic acid, and potassium salts or sodium salts of these higher fatty acids are preferred. Examples of the alkyl sulfate-based surfactant include sodium lauryl sulfate, sodium olefin (C12-14) sulfonate, sodium alkyl (C14-17) s-sulfonate, and sodium tetradecene sulfonate. Examples of the POE alkyl ether sulfate-based surfactant include sodium laures sulfate. More preferably, examples include sodium alkylbenzene sulfonate such as sodium tetradecene sulfonate and sodium lauroyl methyl taurate. Component (D) may be used alone or in combination of two or more. Further, component (D) may be used together with the above-described component (C) or instead of component (C). When component (C) is present, component (D) may be optional.

[0017] The content of the above component (D) is, for example, 0.01 to 20% by mass, preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass with respect to the mass of the entire external composition having fluidity. When the component (C) is also present, the content of the component (D) may be adjusted so that the total amount of the component (C) and the component (D) is within these ranges. By setting the content of the component (D) within the said range, the above-described effects can be sufficiently exhibited.

[0018] In addition to the above components (A) to (D), optional components usually used in the external composition having fluidity can be contained in the external composition having fluidity as needed. Examples of the optional components include humectants, preservatives, pH adjusters, sequestering agents, surfactants other than the above (C) / (D), solvents, and the like. These optional components can be appropriately selected within a range that does not impair the effects of the present invention, and the optional components can be blended in appropriate amounts. One compound may have a plurality of characteristics (for example, a humectant and a surfactant).

[0019] Examples of the humectant include polyhydric alcohols such as glycerin, diglycerin, sorbitol, polyethylene glycol, propylene glycol, ethylene glycol, 1,3-butylene glycol, polypropylene glycol, xylitol, maltitol, lactitol, trehalose, and glycosyl trehalose. The blending amount of the wetting agent is generally 0.01% by mass to 80% by mass, preferably 1 to 10% by mass based on the total mass of the external composition having fluidity. Examples of the preservative include glycerin fatty acid esters, phenoxyethanol, paraoxybenzoic acid esters, benzoic acid and its salts, salicylic acid and its salts, sorbic acid and its salts, l-menthol, d-camphor, isopropylmethylphenol, and the like. The blending amount of the preservative is generally 0.001% by mass to 10% by mass, preferably 0.1 to 5% by mass based on the total mass of the external composition having fluidity.

[0020] Examples of the pH adjuster include citric acid, phosphoric acid, pantothenic acid, malic acid, pyrophosphoric acid, lactic acid, tartaric acid, glycerophosphoric acid, acetic acid, nitric acid, silicic acid, metaphosphoric acid, polyphosphoric acid, and chemically possible salts thereof (e.g., sodium salt, potassium salt, magnesium salt, calcium salt, etc.), as well as sodium hydroxide, potassium hydroxide, disodium hydrogen phosphate, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, sodium citrate, and the like. The compounding amount of the pH adjuster is generally 0.01% by mass to 10% by mass, preferably 0.1% to 50% by mass, based on the total mass of the above-mentioned fluid external composition. Examples of the sequestering agent include edetic acid, edetate, trisodium ethylenediaminehydroxyethyltriacetate, diethylenetriaminepentaacetic acid, pentasodium diethylenetriaminepentaacetate, ethylenediaminetetrakis(2-hydroxyisopropyl)dioleate, hydroxyethanediphosphonic acid, tetrasodium hydroxyethanediphosphonate, phytic acid, and disodium edetate.

[0021] Examples of the surfactant other than (C) / (D) include distearyldimonium chloride, cetylpyridinium chloride, benzethonium chloride, benzalkonium chloride, sucrose fatty acid ester, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene block copolymer, alkyl glycosides, sorbitan fatty acid ester, glycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, lecithin (soybean or egg yolk) and its derivatives, and the like. The compounding amount of the surfactant other than (C) / (D) is generally 0.01% by mass to 10% by mass based on the total mass of the above-mentioned fluid external composition. Examples of the solvent include organic solvents such as ethanol, propyl alcohol, and isopropyl alcohol, and water (pure water, purified water, ion-exchanged water, etc.). The compounding amount of the solvent is generally 0.01% by mass to 99% by mass based on the total mass of the above-mentioned fluid external composition.

[0022] [Physical Properties and Uses of the Fluid External Composition] The fluid external composition of the present invention can be in various forms such as paste, gel, cream, liquid, etc. at normal temperature (for example, 25°C ± 5°C). The fluid external composition can take forms such as cream, lotion, emulsion, plaster, etc. The fluid external composition of the present invention can be used as a cleanser, massage agent, moisturizer, blood circulation promoter, etc. for the body, especially the skin and scalp. The cleanser is particularly effective in removing old cutin and dirt in pores. The blood circulation promoter exhibits good effects due to the massage effect of the present invention. Here, the "external use" means each part of the body surface which is a preferred application site of the fluid external composition, and can mean, for example, use on the skin, scalp, nails, etc. Here, the "skin" in the broad sense includes the scalp and nails.

[0023] [Manufacturing Method of the Fluid External Composition] The above fluid external composition can be manufactured by a general preparation method of a composition containing a plurality of components, such as a step of mixing component (A), component (B), component (C) and / or component (D). The order of mixing each component is not particularly limited, and they may be mixed one by one in order, or all components may be mixed simultaneously. In addition to the mixing step, the above fluid external composition can be prepared together with an additional optional step of blending other optional components according to the steps usually used in the manufacturing method of the fluid external composition.

[0024] [Characteristics of the Fluid External Composition] The topical composition with fluidity has appropriate fluidity. Fluidity means that the composition is not solid but in a fluid state and has a low dynamic viscosity. The fluidity can be defined, for example, as the viscosity measured by a rotational viscometer (No. 6 rotor, 10 revolutions per minute, 60 seconds, 25 °C) being, for example, 100,000 mPa·s or less, preferably 50,000 mPa·s or less, more preferably 10,000 mPa·s or less, and more specifically, for example, 2,000 to 100,000 mPa·s, preferably 3,000 to 50,000 mPa·s, more preferably 4,300 to 10,000 mPa·s. The fluidity can also be specified by sensory evaluation by touch and visual inspection. For example, it can be evaluated by testers who have received sensory evaluation training based on criteria such as whether the sample is easy to spread on the skin, easy to stir, and visually uniform. The above-mentioned topical composition with fluidity may be acidic, neutral, or alkaline, but is preferably neutral or acidic, more preferably weakly acidic. The pH of a specific topical composition with fluidity is suitably, for example, 3.0 to 10.0, preferably 3.5 to 8.0, more preferably 4.0 to 6.0. The above-mentioned topical composition with fluidity is further excellent in stability. Here, "stability" means that the composition is physically and chemically stable and there is no change in the composition even under conditions such as specific temperature, time, and humidity. The above-mentioned topical composition with fluidity is suitably stable, for example, for 24 hours or more, preferably 7 days or more, more preferably 30 days or more under temperature conditions of 25 °C or 50 °C. The above-mentioned topical composition with fluidity is particularly easy to spread and has a good feeling in use when applied on the body surface. Here, "feeling in use" refers to a state where when the topical composition with fluidity is applied to the surface of an application target such as the skin, due to the good fluidity of the topical composition with fluidity, the topical composition with fluidity can be evenly spread on the application target surface.

Examples

[0025] Hereinafter, specific examples of the fluid external composition of the present invention will be described, but it is clearly stated for confirmation that these examples are not intended to limit the scope of the present invention. Also, % means mass % except for the residual ratio.

[0026] [Components Used in Examples and Comparative Examples] The components used in the examples and comparative examples are as follows. · Sodium chloride: Manufactured by Nippon Shio seizo Co., Ltd., Product name: Refined salt, Particle size (measurement method: sieving method): 0.18 - 0.5 mm · Cellulose nanofiber (1): Manufactured by Nippon Paper Industries Co., Ltd., Product name: Celenpia CS-01C, Average fiber diameter: 3 - 100 nm · Cellulose nanofiber (2): Manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Product name: Reocrista C-2SP, Average fiber diameter: 3 nm · Cellulose nanofiber (3): Manufactured by Oji Holdings Corporation, Product name: Aurovis CS, Average fiber diameter: 3 - 4 nm · Cocamidopropyl betaine: Manufactured by Kawa Ken Fine Chemicals Co., Ltd., Product name Softazoline CPB-R · Sodium cocoamphoacetate: Manufactured by Kawa Ken Fine Chemicals Co., Ltd., Product name Softazoline CH-R · Sodium tetradecene sulfonate: Manufactured by Lion Specialty Chemicals Co., Ltd., Product name: K Lipolan PJ-400CJ · Sodium lauroyl methyl taurate: Manufactured by Nippon Surfactant Industry Co., Ltd., Product name: NIKKOL LMT-P · Distearyldimonium chloride: Manufactured by Nippon Surfactant Industry Co., Ltd., Product name: NIKKOL CA-3475V · Polyoxyethylene hydrogenated castor oil (PEG-60 hydrogenated castor oil): Manufactured by Nippon Surfactant Industry Co., Ltd., Product name: NIKKOL HCO-60 · Sodium carboxymethyl cellulose (CMC·Na): Manufactured by Daicel Miraiz Co., Ltd., Product name: CMC Daicel 1260 For some of the above products, they are in the state of an aqueous solution containing the essential components. However, the mass % described in this specification and the table refers only to the essential components and does not include water and the like contained in the products.

[0027] [Preparation of the flowable external composition of Example 1] Each component described in Example 1 of Table 1 was mixed using a stirrer to obtain the flowable external composition of Example 1. [Preparation of the flowable external compositions of Examples 2 to 17 and Comparative Examples 1 to 5] The flowable external compositions of Examples 2 to 17 and Comparative Examples 1 to 5 were obtained in the same manner as in Example 1, except that the components in the ratios described in Tables 1 to 3 were used.

[0028] [Evaluation of fluidity] The fluidity of the obtained flowable external compositions (samples) of the Examples and Comparative Examples was evaluated by the viscosity measured with a rotational viscometer (manufactured by Brookfield, No. 6 rotor, 10 revolutions per minute, 60 seconds, 25 °C). The evaluation criteria are as follows. A (Best): 4,300 to 10,000 B (Excellent): Less than 2,000 to 4,300, or more than 10,000 to 100,000 E (Poor): Less than 2,000 or more than 100,000

[0029] [Evaluation of pH] The pH of the obtained flowable external compositions (samples) of the Examples and Comparative Examples was measured with a pH meter (manufactured by Horiba, Ltd.) and evaluated according to the following criteria. A (Best): 4.0 to 6.0 B (Excellent): Less than 3.0 to 4.0, or more than 6.0 to 10.0 E (Poor): Less than 3.0 or more than 10.0

[0030] [Evaluation of stability] The obtained flowable external compositions (samples) of the Examples and Comparative Examples were stored in an environment at room temperature (25 °C) and 50 °C, respectively, and the state of the composition was evaluated by visual inspection. The evaluation was carried out according to the following criteria. A (Best): Stable at 50 °C for at least 30 days B (Excellent): Stable at 50 °C for at least 7 days, but not maintaining the state until 30 days at 50 °C C (Good): Stable for at least 24 hours at 50°C, but does not maintain its state up to 7 days at 50°C D (Fair): Stable for at least 24 hours at room temperature (25°C), but does not maintain its state up to 24 hours at 50°C E (Bad): Separates in less than 24 hours at room temperature (25°C) (does not maintain its state)

[0031] [Evaluation of usability] A total of 3 men and women in their 20s to 40s who had received training in sensory evaluation applied each of the obtained fluid external compositions (samples) of the examples and comparative examples independently to the skin on the inner forearm and conducted the following evaluations through discussion. A (Outstanding): High fluidity and very good spreadability B (Excellent): High fluidity and good spreadability C (Good): Has fluidity and can be spread with a little force D (Fair): Low fluidity, but can be mixed and stirred by hand E (Bad): The sample is non-uniform and cannot be spread evenly The above evaluation results are shown in Tables 1 to 3.

[0032]

Table 1

[0033]

Table 2

[0034]

Table 3

[0035] From the results of the above Tables 1 to 3, it was found that the fluid external composition of the present invention exhibits good stability and usability. More specifically, the following points became clear. · From Examples 1 to 3 and Comparative Examples 1 to 3, by blending (B) nanofibers, (C) amphoteric surfactant, and (D) anionic surfactant, the stability of the formulation containing (A) inorganic salt particles can be improved. · From Examples 1 to 3 and Comparative Example 4, by using (B) nanofibers, the stability of the formulation can be improved compared to the case of using sodium carboxymethyl cellulose. · From Examples 1 to 3 and Comparative Example 5, even if (D) cationic surfactant is blended instead of (C) amphoteric surfactant, the stability of the formulation containing (A) inorganic salt particles and (B) nanofibers can be maintained to a certain extent. · From Examples 4 to 5, cellulose nanofibers are desirable as (B) nanofibers. · From Examples 6 to 7, various surfactants can be used as (C) amphoteric surfactant and (D) anionic surfactant. · From Examples 8 to 9, increasing the concentration of cellulose nanofibers improves the stability. · From Examples 10 to 13, the amount of (A) inorganic salt particles is desirably 25 to 55% by mass. · From Examples 14 to 15, the amount of (C) amphoteric surfactant is desirably 0.3 to 1.8% by mass. · From Examples 16 to 17, the amount of (D) anionic surfactant is desirably 1 to 6% by mass.

Claims

1. A flowable external composition containing (A) inorganic salt particles, (B) nanofibers, (C) an amphoteric surfactant, or (D) an anionic surfactant.

2. The flowable external composition according to claim 1, containing both (C) an amphoteric surfactant and (D) an anionic surfactant.

3. The flowable external composition according to claim 1 or 2, wherein the inorganic salt is sodium chloride and / or magnesium chloride.

4. The flowable external composition according to claim 1 or 2, wherein (B) the nanofibers are cellulose nanofibers.

5. The flowable external composition according to claim 1 or 2, containing component (C), and component (C) being coconut fatty acid amide propyl betaine or sodium cocoamphoacetate.

6. The flowable external composition according to claim 1 or 2, containing component (D), and component (D) being sodium tetradecene sulfonate or sodium lauroyl methyl taurate.

7. The flowable external composition according to claim 1 or 2, wherein the content of component (B) is 0.1 to 10% by mass based on the total amount of the flowable external composition.

8. The flowable external composition according to claim 1 or 2, wherein the content of component (A) is 1 to 90% by mass based on the total amount of the flowable external composition.

9. The flowable external composition according to claim 1 or 2, wherein the viscosity of the flowable external composition measured with a rotational viscometer is 100,000 mPa·s or less.

10. A skin cleanser containing the flowable external composition according to claim 1 or 2.

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