Bath solid composition

Abstract

The present invention provides a solid bath composition containing an oil agent, which can be solidified, dissolves slowly in bath water, and produces little foam in the bath water. [Solution] The following components (A) and (B): (A) Oils (B) Nonionic surfactants with a melting point of 25°C or higher A solid bath composition containing the above, wherein the content of component (B) in the solid bath composition is 20% by mass or more, and the mass ratio of component (A) to component (B) (A) / (B) is 0.20 or more.

Description

[Technical Field]

[0001] This invention relates to a solid composition for use in baths. [Background technology]

[0002] It is known that including oils in bath salts can further enhance their moisturizing and warming effects. Bath additives or bath cosmetics that contain oils and are solid are also being investigated. For example, Patent Document 1 discloses a bath additive composition containing a powder composition comprising an oily component containing at least one type of carotenoid, a surfactant containing at least one type of phospholipid, and an excipient, wherein the amount of the surfactant is within a predetermined range relative to the oily component, which is easily dispersed uniformly in bath water, does not impair the appearance of the bath water, and has excellent skin care effects and stability. Patent Document 2 discloses that a fragrance granule containing a predetermined amount of liquid nonionic surfactant, fragrance, and polyoxyalkylene, wherein the average number of added moles of HLB and ethyleneoxy groups is above a predetermined value, can suppress the occurrence of stickiness and sufficiently increase particle strength, thereby improving storage stability and moldability when applied as a component in bath additives and the like.

[0003] Solid bath additives that contain organic acids and carbonates and produce carbonate-like bubbles are also known. For example, Patent Document 3 discloses a bath additive composition containing organic acids, carbonates, a nonionic surfactant, polyethylene glycol having a number-average molecular weight within a predetermined range, and a thickener, which generates fine bubbles on the surface of the bathwater, can retain those bubbles well, and can also achieve high storage stability. Furthermore, Patent Document 4 discloses a solid bath additive containing an organic acid, a carbonate, and an oily component, comprising granules containing one or more oils selected from fatty acid esters and fatty acid glycers, an oily component containing a predetermined nonionic surfactant, and a water-soluble polymer in a specific proportion, as well as a foaming bath additive composition containing a carbonate and an organic acid, and states that the granules have good granulation properties while increasing the proportion of oily components in order to sufficiently enhance the warming effect of carbon dioxide. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2009-132628 [Patent Document 2] Japanese Patent Publication No. 2014-94915 [Patent Document 3] Japanese Patent Publication No. 2015-113320 [Patent Document 4] Japanese Patent Publication No. 2019-142792 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] As described in the aforementioned patent document, in solid bath additives or bath cosmetics containing oils, the oil is supported on a solid material. These solid bath additives or bath cosmetics can contain a large amount of oil to provide moisturizing effects, etc., and even in such cases, it is required that they be able to be solidified. Furthermore, if the foam does not dissipate well from the surface of the bathwater when added to the bath, the appearance of the bathwater will be poor, and it may induce the washing away of foam and oil after bathing, which may reduce the moisturizing effect of the oil. Therefore, it is also desirable to suppress foaming of the bathwater.

[0006] Furthermore, bath additives that require moisturizing effects, as well as bath products that are applied to the skin while bathing. In cosmetics, it is considered that the moisturizing effect can be enhanced by unevenly distributing an oil agent on the skin surface during use. At this time, bath agents and bath cosmetics are desired to have the property of dissolving slowly in bath water because if they dissolve too quickly in bath water, it becomes difficult to unevenly distribute the oil agent.

[0007] The present invention relates to a solid bath composition containing an oil agent, which can be solidified, has the property of slowly dissolving in bath water, and has little foaming in bath water.

Means for Solving the Problems

[0008] The present inventor has found that the above problems can be solved by using a solid bath composition containing an oil agent and a specific nonionic surfactant at a specific ratio. That is, the present invention relates to the following. [1] The following components (A) and (B): (A) Oil agent (B) Nonionic surfactant having a melting point of 25°C or higher A solid bath composition containing the above, wherein the content of the component (B) in the solid bath composition is 20% by mass or more, and the mass ratio (A) / (B) of the component (A) to the component (B) is 0.20 or more. [2] A bath agent containing the solid bath composition according to [1] above. [3] A bath cosmetic containing the solid bath composition according to [1] above.

Effects of the Invention

[0009] According to the present invention, it is possible to provide a solid bath composition that can be solidified while containing an oil agent, has the property of slowly dissolving in bath water, and has little foaming in bath water.

Brief Description of the Drawings

[0010] [Figure 1] It is a photographed image when observing the state of the component (B) in the solid bath composition of Example 25 with a scanning electron microscope (SEM). [Figure 2]This is a small-angle X-ray scattering (SAXS) measurement chart of the bath solid composition and component (B) of Example 26. [Modes for carrying out the invention]

[0011] [Solid composition for baths] The bath solid composition of the present invention comprises the following components (A) and (B): (A) Oils (B) Nonionic surfactants with a melting point of 25°C or higher A solid bath composition containing the above, wherein the content of component (B) in the solid bath composition is 20% by mass or more, and the mass ratio of component (A) to component (B), (A) / (B), is 0.20 or more.

[0012] In this invention, "solid" means solid at 25°C. Furthermore, the "bath solid composition" of this invention means a solid composition that constitutes at least a part of a bath additive or bath cosmetic, and includes both solid compositions that can be used as a bath additive as is, and solid compositions that are used by being incorporated into a bath additive or bath cosmetic as a component of the bath additive or bath cosmetic. In other words, the bath solid composition of this invention is also an intermediate product of a bath additive or bath cosmetic.

[0013] The bath solid composition of the present invention, by having the above configuration, can be solidified while containing an oil agent, has the property of dissolving slowly in bath water, and produces less foam in the bath water.

[0014] <Ingredient (A): Oil> The bath solid composition of the present invention (hereinafter also simply referred to as "the composition") contains an oil as component (A). Component (A) is preferably a liquid oil, from the viewpoint of supporting it on component (B), etc., and from the viewpoint of improving the user experience when spreading it on the skin in the bath. In this invention, "liquid oil" refers to an oil that is fluid under 1 atmosphere and 25°C, and "solid oil" refers to an oil that is not fluid under the same conditions.

[0015] Component (A) is typically an oil used in cosmetics, and includes, for example, one or more selected from the group consisting of silicone oil, ester oil, ether oil, hydrocarbon oil, higher alcohol, and higher fatty acid.

[0016] (Silicone oil) As the silicone oil, one or more selected from the group consisting of dimethylpolysiloxane (dimethicone), dimethiconol (dimethylpolysiloxane having a hydroxyl group at the end), methylphenylpolysiloxane, and modified silicones are preferred. Examples of modified silicones include amino-modified silicones (dimethylpolysiloxanes having amino groups, such as amodimethicone), polyether-modified silicones, aminopolyether-modified silicones (silicones having amino groups and polyether structures), glyceryl-modified silicones, carboxy-modified silicones, fatty acid-modified silicones, alcohol-modified silicones, aliphatic alcohol-modified silicones, epoxy-modified silicones, fluorine-modified silicones, alkyl-modified silicones, and the like. Among the above, from the viewpoint of facilitating the solidification of the composition and improving the feel when used by spreading it on the skin in a bath, the silicone oil is preferably one or more selected from the group consisting of dimethylpolysiloxane, dimethiconol, methylphenylpolysiloxane, and modified silicone, more preferably one or more selected from the group consisting of dimethylpolysiloxane, dimethiconol, amino-modified silicone, polyether-modified silicone, and aminopolyether-modified silicone, and even more preferably dimethylpolysiloxane.

[0017] (Ester oil) The ester oil is preferably in liquid form under 1 atmosphere and 25°C. Examples of ester oils include esters of monocarboxylic acid and monohydric alcohol, esters of monocarboxylic acid and polyhydric alcohol, and esters of polyhydric acid and monohydric alcohol.

[0018] Examples of esters of monovalent carboxylic acids and monovalent alcohols include esters represented by the following general formula (1). R 1 -COO-R 2 (1) In general formula (1), R 1 The hydroxyl group may be substituted, and the carbon atoms must be between 1 and 25. R represents a linear or branched alkyl or alkenyl group, or an aromatic hydrocarbon group having 6 to 24 carbon atoms. 2 This is a linear or branched alkyl group having 1 to 30 carbon atoms or This indicates an alkenyl group.

[0019] R 1 When is an alkyl group or alkenyl group, the number of carbon atoms is preferably 7 or more, and Preferably, it is 23 or less, more preferably 21 or less, even more preferably 19 or less, and even more preferably 17 or less. R 1 If it is an aromatic hydrocarbon group, the number of carbon atoms is preferably 6 or more, and is preferable It is at least 22, more preferably 20 or less. R 2 The number of carbon atoms is preferably 2 or more, and more preferably 28 or less. The value of k is 24 or less, and more preferably 20 or less.

[0020] Specific examples of esters represented by general formula (1) include cetyl isooctanoate, isooctanoate, and One or more selected from the group consisting of stearyl tannate, isononyl isononanoate, isotridecyl isononanoate, hexyl laurate, isostearyl laurate, butyl myristate, isopropyl myristate, decyl myristate, isotridecyl myristate, isocetyl myristate, isostearyl myristate, octyldodecyl myristate, isopropyl palmitate, 2-ethylhexyl palmitate, isostearyl palmitate, 2-hexyldecyl palmitate, 2-ethylhexyl stearate, 2-hexyldecyl stearate, isopropyl isostearate, 2-hexyldecyl isostearate, ethyl oleate, isodecyl oleate, oleyl oleate, octyldodecyl oleate, ethyl linoleate, isopropyl linoleate, lanolin acetate, methyl castor oil fatty acid (methyl ricinoleate), and alkyl benzoate (alkyl having 12 to 15 carbon atoms) may be mentioned. These are liquid under the environment of 25 °C at 1 atm.

[0021] As an ester of a monovalent carboxylic acid and a monovalent alcohol, an ester represented by the following general formula (2) may also be mentioned. R 3 -COO-(AO) n -R 4 (2) In general formula (2), R 3 may be substituted with a hydroxyl group and represents a linear or branched alkyl group or alkenyl group having 1 to 25 carbon atoms, and R represents an aromatic-containing hydrocarbon group having 6 to 24 carbon atoms. AO represents an alkyleneoxy group having 2 to 4 carbon atoms, and n represents an average addition mole number of 1 to 50. 4 preferably has 7 or more carbon atoms, and preferably 23 or less, more preferably 21 or less, still more preferably 19 or less, and is an alkyl group. R 3 preferably has 6 or more carbon atoms, and preferably 22 or less, more preferably 20 or less, still more preferably 18 or less, and is an alkyl group. R 4 preferably has 6 or more carbon atoms, and preferably 22 or less, more preferably k is an aromatic hydrocarbon group with a value of 20 or less, more preferably 18 or less, and even more preferably a benzyl group. The AO group is preferably a propyleneoxy group, and n is preferably 1 to 10, more preferably 1 to 5. Specific examples of esters represented by general formula (2) include esters of myristic acid and a 3-mol propylene oxide adduct of benzyl alcohol, and esters of 2-ethylhexanoic acid and a 3-mol propylene oxide adduct of benzyl alcohol.

[0022] Examples of esters of monocarboxylic acids and polyhydric alcohols include esters represented by the following general formula (3). R 5 -(OCOR 6 ) p (3) In general formula (3), R 5 This represents a polyhydric alcohol residue, preferably with 2 or more carbon atoms. A hydrocarbon group with a value of 0 or less, R 6 This represents a monovalent carboxylic acid residue with 1 to 25 carbon atoms. p represents an integer between 2 and 10 (inclusive). Note, R 5 It may have ether bonds, but preferably a linear chain with 2 to 10 carbon atoms. Alternatively, it is a branched hydrocarbon group. Also, p is the same number as the hydroxyl groups present in the polyhydric alcohol. R 6 Preferably, the carbon number is 7 or more, and more preferably 23 or less. k is an alkyl group with a value of 21 or less, and more preferably 19 or less.

[0023] Examples of esters represented by general formula (3) include propylene glycol dicaprate, propylene glycol dioleate, neopentyl glycol dicaprate, neopentyl glycol di2-ethylhexanoate, di(caprylic / capric acid)propanediol, propanediol diisostearate, ethylene glycol di2-ethylhexanoate, caprylic / capric acid triglyceride, glyceryl tri2-ethylhexylate, glyceryl tri2-heptylundecanoate, trimethylolpropane tri2-ethylhexylate, trimethylolpropane triisostearate, and pentaerythritol tetra-2-ethylhexanoate. These are liquid under 1 atmosphere and 25°C. Ester oils can be either synthetic ester oils or natural oils and fats. Examples of natural oils and fats include triglycerides such as avocado oil, olive oil, sesame oil, rice bran oil, safflower oil, soybean oil, corn oil, rapeseed oil, castor oil, cottonseed oil, and mink oil. These are liquid under 1 atmosphere and 25°C.

[0024] Esters of polycarboxylic acids and monohydric alcohols include those represented by the following general formula (4). R 7 -(COOR 8 ) q (4) In general formula (4), R 7 R is a polyvalent carboxylic acid residue having 2 to 10 carbon atoms. 8 represents a monohydric alcohol residue with 1 to 25 carbon atoms, and q is an integer between 2 and 10. Furthermore, q is the same number as the carboxyl groups present in the polyhydric carboxylic acid. R 8 It is preferably 3 or more, and preferably 23 or less, more preferably 21 More preferably, the number is 19 or less. Specifically, examples include diisostearyl malate, di-2-ethylhexyl succinate, diisobutyl adipate, di-2-heptyl undecyl adipate, di-2-ethylhexyl sebacate, diisopropyl sebacate, and tri-2-ethylhexyl trimellitate. These are liquid under 1 atmosphere and 25°C.

[0025] Among the above, from the viewpoint of facilitating the solidification of the composition and improving the feel when used by spreading it on the skin in the bath, the ester oil is preferably one or more selected from the group consisting of esters represented by general formula (1), general formula (3), and general formula (4), more preferably one or more selected from the group consisting of esters represented by general formula (1) and general formula (3), and even more preferably one or more selected from the group consisting of isopropyl myristate, isopropyl palmitate, and tri(caprylic / capric acid)glyceride.

[0026] (Ether oil) The ether oil is preferably in liquid form under 1 atmosphere and 25°C. Examples of ether oils include dialkyl ether compounds represented by the following general formula (5). R 9 -OR 10 (5) In general formula (5), R 9 and R 10 Each of these is independently a linear or This represents a branched alkyl or alkenyl group, or an aromatic hydrocarbon group having 6 to 24 carbon atoms. R 9 and R 10 This is from the viewpoint of facilitating the solidification of the composition, and while spreading it on the skin in the bath. From the viewpoint of improving the user experience during use, the alkyl group is preferable, and the number of carbon atoms is preferably 8 or more, preferably 18 or less, more preferably 16 or less, and even more preferably 12 or less.

[0027] (Hydrogen oil) The hydrocarbon oil is preferably in liquid form at 1 atmosphere and 25°C. Examples of hydrocarbon oils include one or more selected from the group consisting of squalene, squalane, liquid paraffin, liquid isoparaffin, isohexadecane, isoeicosane, hydrogenated polyisobutene, light liquid isoparaffin, heavy liquid isoparaffin, α-olefin oligomer, and cycloparaffin. These are liquid at 1 atmosphere and 25°C.

[0028] (High-grade alcohol) The higher alcohol is preferably in liquid form at 1 atmosphere and 25°C. The higher alcohol is preferably an aliphatic monohydric alcohol having 12 or more carbon atoms, preferably 12 to 22 carbon atoms. Examples include lauryl alcohol, cetyl alcohol, myristyl alcohol, oleyl alcohol, stearyl alcohol, isostearyl alcohol, and 2-olamine alcohol. One or more substances selected from the group consisting of cutyldodecanol, behenyl alcohol, and cetostearyl alcohol are included. Furthermore, lauryl alcohol, oleyl alcohol, isostearyl alcohol, and 2-octyldodecanol are liquids at 1 atmosphere and 25°C, while cetyl alcohol, myristyl alcohol, stearyl alcohol, behenyl alcohol, and cetostearyl alcohol are solids at 1 atmosphere and 25°C.

[0029] (higher fatty acids) The higher fatty acids are preferably in liquid form under 1 atmosphere and 25°C. Preferred higher fatty acids are those with 8 or more carbon atoms, preferably 12 or more carbon atoms. Examples include one or more selected from the group consisting of capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, coconut oil fatty acid, isostearyl acid, and isopalmitic acid. Note that oleic acid, isostearyl acid, and isopalmitic acid are liquid under 1 atmosphere and 25°C, while capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, and coconut oil fatty acid are solid.

[0030] Component (A) can be used in combination of one or more of the above. Among the above, component (A) is preferably one or more selected from the group consisting of silicone oil, ester oil, and hydrocarbon oil, from the viewpoint of facilitating the solidification of the composition and improving the feel when used while spreading it on the skin in the bath; more preferably one or more selected from the group consisting of ester oil and hydrocarbon oil; even more preferably one or more selected from the group consisting of ester represented by the general formula (1), ester represented by the general formula (3), dimethylpolysiloxane, and liquid paraffin; even more preferably one or more selected from the group consisting of tri(caprylic / capric acid) glyceryl, isopropyl myristate, isopropyl palmitate, and liquid paraffin; and even more preferably one or more selected from the group consisting of tri(caprylic / capric acid) glyceryl, isopropyl myristate, and isopropyl palmitate.

[0031] <Component (B): Nonionic surfactant with a melting point of 25°C or higher> The bath solid composition of the present invention contains a nonionic surfactant with a melting point of 25°C or higher as component (B). By containing component (B) in a predetermined proportion, the bath solid composition of the present invention can be solidified while containing an oil agent, has the property of dissolving slowly in bath water, and produces less foam in the bath water. The nonionic surfactant, which is component (B), is thought to form plate-like molecular crystals at room temperature (25°C), and it is thought that a large amount of oil agent can be supported in the voids of these crystals.

[0032] From the viewpoint of supporting a large amount of the oil component (A) and facilitating the solidification of the composition, the melting point of component (B) is preferably 30°C or higher, more preferably 35°C or higher. There is no upper limit to the melting point of component (B), but it is usually 100°C or lower, and preferably 80°C or lower.

[0033] Specific examples of component (B) include polyoxyethylene alkyl ethers, polyoxyethylene alkenyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, alkyl glucosides, alkyl alkanolamides, alkyl glyceryl ethers, higher fatty acid sucrose esters, polyglycerin fatty acid esters, polyoxyethylene hydrogenated castor oil, alkyl saccharides, etc., all of which have a melting point of 25°C or higher. One or more of these can be used.

[0034] Of the above component (B), polyoxyethylene alkyl ether, polyoxyethylene The number of carbon atoms in the alkyl or alkenyl in lukenyl ethers, alkyl glucosides, alkyl alkanolamides, alkyl glyceryl ethers, and alkyl saccharides, and the number of carbon atoms in the constituent fatty acids in polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, higher fatty acid sucrose esters, and polyglycerin fatty acid esters, are preferably 8 or more, more preferably 10 or more, even more preferably 12 or more, and even more preferably 14 or more, from the viewpoint of facilitating the solidification of the composition, and preferably 36 or less, more preferably 32 or less, even more preferably 28 or less, and even more preferably 24 or less, from the viewpoint of suppressing foaming of the bath water.

[0035] Of the components (B) mentioned above, the average number of moles of ethylene oxide added in polyoxyethylene alkyl ethers, polyoxyethylene alkenyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyglycerin fatty acid esters, and polyoxyethylene hydrogenated castor oil (hereinafter also referred to as "average number of moles of EO added") is preferably 10 or more, more preferably 15 or more, even more preferably 18 or more, and also preferably 200 or less, more preferably 150 or less, even more preferably 120 or less, even more preferably 100 or less, even more preferably 80 or less, even more preferably 60 or less, and even more preferably 40 or less. Furthermore, when using two or more polyoxyethylene alkyl ethers, polyoxyethylene alkenyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyglycerin fatty acid esters, or polyoxyethylene hydrogenated castor oil as component (B), the average number of EO added is the weighted average of the average number of EO added by the two or more components.

[0036] The average number of moles of EO added to component (B) can be determined by high-performance liquid chromatography (HPLC). For example, the average number of moles of ethylene oxide added to polyoxyethylene alkyl ether can be determined by the method described in Japanese Patent Application Publication No. 2019-182828.

[0037] Among the aforementioned components (B), from the viewpoint of facilitating the solidification of the composition and suppressing foaming of the bath water, component (B) is preferably one or more selected from the group consisting of polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene sorbitan fatty acid ester, and more preferably contains polyoxyethylene alkyl ether.

[0038] Specific examples of polyoxyethylene alkyl ethers include polyoxyethylene octyl ether, polyoxyethylene ethylhexyl ether, polyoxyethylene nonyl ether, polyoxyethylene decyl ether, polyoxyethylene undecyl ether, polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyethylene myristyl ether, polyoxyethylene pentadecyl ether, polyoxyethylene cetyl ether, polyoxyethylene heptadecyl ether, polyoxyethylene stearyl ether, and polyoxyethylene behenyl ether. One or more of these can be used in combination. Among the above, from the viewpoint of facilitating the solidification of the composition, preferably one or more selected from the group consisting of polyoxyethylene decyl ether, polyoxyethylene undecyl ether, polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyethylene myristyl ether, polyoxyethylene pentadecyl ether, polyoxyethylene cetyl ether, polyoxyethylene heptadecyl ether, polyoxyethylene stearyl ether, and polyoxyethylene behenyl ether, more preferably This is one or more selected from the group consisting of polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, and polyoxyethylene behenyl ether, and more preferably one or more selected from the group consisting of polyoxyethylene stearyl ether and polyoxyethylene behenyl ether.

[0039] Specific examples of polyoxyethylene fatty acid esters include polyethylene glycol monostearate and polyethylene glycol monooleate, and one or more of these can be used in combination.

[0040] Specific examples of polyoxyethylene sorbitan fatty acid esters include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, polyoxyethylene coconut oil fatty acid sorbitan, and polyoxyethylene sorbitan triisostearate, and one or more of these can be used in combination.

[0041] Among the above, from the viewpoint of facilitating the solidification of the composition and suppressing foaming of the bath water, component (B) is more preferably one or more selected from the group consisting of polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene behenyl ether, polyethylene glyco monostearate, and polyoxyethylene sorbitan triisostearate, even more preferably one or more selected from the group consisting of polyoxyethylene stearyl ether, polyoxyethylene behenyl ether, polyethylene glyco monostearate, and polyoxyethylene sorbitan triisostearate, and even more preferably one or more selected from the group consisting of polyoxyethylene stearyl ether and polyoxyethylene behenyl ether.

[0042] The bath solid composition of the present invention may also contain nonionic surfactants other than component (B). However, if the bath solid composition contains nonionic surfactants other than component (B), the amount thereof is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 2% by mass or less, even more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and even more preferably 0% by mass, from the viewpoint of facilitating the solidification of the composition.

[0043] <Content> The content of component (A) in the bath solid composition is preferably 4% by mass or more, more preferably 10% by mass or more, even more preferably 17% by mass or more, even more preferably 20% by mass or more, even more preferably 25% by mass or more, and even more preferably 30% by mass or more, from the viewpoint of improving the feel when used by spreading it on the skin in the bath, and preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less, from the viewpoint of facilitating the solidification of the composition.

[0044] The content of component (B) in the solid bath composition is 20% by mass or more, from the viewpoint of facilitating the solidification of the composition and imparting the property of slowly dissolving in bath water, and from the viewpoint of suppressing foaming of the bath water, it is preferably 83% by mass or less, more preferably 80% by mass or less, even more preferably 75% by mass or less, and even more preferably 70% by mass or less.

[0045] In the bath solid composition of the present invention, the mass ratio (A) / (B) of component (A) to component (B) is 0.20 or higher, preferably 0.30 or higher, more preferably 0.40 or higher, and even more preferably 0.50 or higher, from the viewpoint of suppressing foaming of the bath water. Furthermore, from the viewpoint of enabling the composition to solidify and imparting the property of slowly dissolving in bath water, it is preferably 4.0 or lower.

[0046] The total content of component (A) and component (B) in the solid bath composition is preferably 24% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, and even more preferably 50% by mass or more, from the viewpoint of imparting the property of slowly dissolving in bath water and improving the feel when used by spreading it on the skin in the bath. The upper limit is 100% by mass or less, and from the viewpoint of facilitating the solidification of the composition and the freedom of formulation, it is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less.

[0047] <Component (C): Water-soluble polymer> The bath solid composition of the present invention may further contain a water-soluble polymer as component (C) from the viewpoint of supporting component (A) and improving moldability. Examples of the water-soluble polymers include synthetic water-soluble polymers such as polyethylene glycol, polyvinylpyrrolidone, sodium polyacrylate, polyethyleneimine, and polyvinyl alcohol; natural water-soluble polymers such as glue, gelatin, collagen protein, casein, sodium alginate, carrageenan, ferceleran, tamarind gum, pectin, gum arabic, guar gum, xanthan gum, tragacanth gum, locust bean gum, dextrin, dextran, agar, and starch; and semi-synthetic water-soluble polymers such as carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, cellulose phthalate acetate, propylene glycol alginate, oxidized starch, esterified starch, etherified starch, and cationic starch; and one or more of these can be used. Among these, from the viewpoint of improving moldability, one or more components selected from the group consisting of polyethylene glycol and dextrin are preferred as component (C), with polyethylene glycol being more preferred. The molecular weight of polyethylene glycol is preferably 4,000 to 20,000, and more preferably 5,000 to 15,000.

[0048] When component (C) is used, the content of component (C) in the bath solid composition is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, from the viewpoint of supporting component (A) and improving moldability. Furthermore, from the viewpoint of improving the feel when used by spreading it on the skin in the bath, the content is 85% by mass or less, preferably 80% by mass or less, and more preferably 70% by mass or less.

[0049] The bath solid composition of the present invention preferably does not contain ionic surfactants, particularly cationic surfactants, from the viewpoint of facilitating the solidification of the composition and improving the feel when used by spreading it on the skin in the bath. The content thereof is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 2% by mass or less, even more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and even more preferably 0% by mass in the bath solid composition.

[0050] The total content of components (A), (B), and (C) in the solid bath composition is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 100% by mass, from the viewpoint of facilitating the solidification of the composition, improving the feel when spreading it on the skin in the bath, suppressing foaming of the bath water, and improving moldability. In other words, it is preferable that the solid bath composition of the present invention contains only components (A), (B), and (C).

[0051] <Dosage form, manufacturing method> The dosage form of the bath solid composition of the present invention is not particularly limited, but from the viewpoint of handling during use Preferably, it is in granular form. The method for producing the bath solid composition is not particularly limited. For example, it can be produced by blending component (A), component (B), and other components as needed, heating them to a temperature above the melting point of the higher component, stirring and mixing them using a known apparatus, and then cooling and solidifying them. When the dosage form is granular, it may be formed as granules, or it may be processed into granules after solidification. When the dosage form of the solid bath composition of the present invention is granular, the particle size is preferably 0.5 mm or larger, more preferably 1 mm or larger, and preferably 3 mm or smaller, more preferably 2 mm or smaller, from the viewpoint of improving handling and improving the rate of dissolution in bath water.

[0052] The bath solid composition of the present invention is preferably a solid composition obtained by heating component (A) and component (B) to a temperature above the melting point of the component with the higher melting point and mixing them. In the bath solid composition of the present invention, component (B) is thought to support component (A). As mentioned above, this is because the nonionic surfactant component (B) forms molecular crystals at room temperature (25°C), and can support a large amount of oil in its voids. If the bath solid composition contains component (C), it is preferable that the bath solid composition be obtained by heating component (A), component (B), and component (C) to a temperature above the melting point of component (B) or component (C) which has a higher melting point, and then mixing them. Furthermore, if component (A) is a liquid oil, component (A) is supported on component (B) as a liquid oil, and if component (A) is a solid oil, component (A) is supported on component (B) as a solid oil.

[0053] <Gel hardness> The bath solid composition of the present invention preferably has a gel hardness of less than 5.0 N, and more preferably less than 3.0 N, at a temperature of 25°C, from the viewpoint of improving the user experience when it is applied to the skin in the bath. The gel hardness of the bath solid composition can be measured using a rheometer by the method described in the examples.

[0054] [Bath additive] The bath additive of the present invention contains the bath solid composition of the present invention described above. The bath additive of the present invention may consist solely of the bath solid composition, or it may also contain other components besides the bath solid composition, such as an organic acid and a carbonate. By including an organic acid and a carbonate in the bath additive, carbon dioxide effervescence can be imparted, and furthermore, the warming effect during bathing can be improved by the synergistic effect of carbon dioxide and component (A).

[0055] If the bath additive consists solely of the bath solid composition, the composition of the bath additive and its preferred form are the same as those of the bath solid composition.

[0056] If the bath additive contains components other than the bath solid composition, the amount of the bath solid composition in the bath additive will vary depending on the composition of the bath solid composition and the types of other components, but is preferably 10% by mass or more and 95% by mass or less, and more preferably 10% by mass or more and 90% by mass or less. If the bath additive contains components other than the bath solid composition, the dosage form of the bath solid composition contained in the bath additive is preferably granular.

[0057] <Organic acid> Examples of organic acids include carboxylic acid compounds, organic sulfonic acid compounds, and organic phosphoric acid compounds, but carboxylic acid compounds are preferred from the viewpoint of effervescence, solubility in bath water, and moldability of the bath additive. The carboxylic acid compound may be any compound having at least one carboxyl group, but from the viewpoint of imparting effervescence, it is preferable to have two or more carboxyl groups. Polycarboxylic acids are preferred. The carboxylic acid compound may be either an aliphatic carboxylic acid or an aromatic carboxylic acid. Examples of aliphatic carboxylic acids include tartaric acid, malic acid, citric acid, maleic acid, glutaric acid, oxalic acid, fumaric acid, succinic acid, and adipic acid, while examples of aromatic carboxylic acids include benzoic acid, salicylic acid, and pyrrolidone carboxylic acid. Among the above, from the viewpoint of the effervescence and moldability of the bath additive, as well as economic efficiency, aliphatic carboxylic acids are preferred as organic acids, one or more selected from the group consisting of fumaric acid, succinic acid, and adipic acid are more preferred, one or more selected from the group consisting of fumaric acid and succinic acid are even more preferred, and the inclusion of fumaric acid is even more preferred.

[0058] When a bath additive contains organic acids, the amount of organic acids in the bath additive is preferably 20% by mass or more, more preferably 30% by mass or more, and preferably 50% by mass or less, from the viewpoint of improving effervescence.

[0059] <Carbonates> Examples of carbonates include dialkali metal carbonates such as sodium carbonate and potassium carbonate; alkali metal bicarbonates such as sodium bicarbonate and potassium bicarbonate; and alkaline earth metal carbonates such as calcium carbonate and magnesium carbonate. One or more of these can be used. From the viewpoint of further improving the effervescence and moldability of the bath additive, it is preferable that the carbonate be one or more selected from the group consisting of sodium carbonate, sodium bicarbonate, and calcium carbonate, more preferably one or more selected from the group consisting of sodium carbonate and sodium bicarbonate, and even more preferably containing sodium carbonate and sodium bicarbonate.

[0060] When a bath additive contains carbonate, the carbonate content in the bath additive is preferably 15% by mass or more, more preferably 20% by mass or more, from the viewpoint of improving foaming properties and moldability. Furthermore, it is preferably 50% by mass or less, more preferably 45% by mass or less.

[0061] When a bath additive contains organic acids and carbonates, the ratio of organic acids to carbonates in the bath additive is preferably 0.5 or more, more preferably 0.8 or more, and preferably 2.0 or less, and more preferably 1.5 or less, as a mass ratio [organic acid / carbonate], from the viewpoint of improving effervescence and improving the dissolution rate of the bath additive in bath water.

[0062] <Other ingredients> The bath additive of the present invention preferably does not contain any nonionic surfactants other than component (B). Furthermore, the bath additive of the present invention may contain, as appropriate, other components commonly used in bath additives, excluding nonionic surfactants other than component (B). Examples of such components include anionic or amphoteric surfactants; inorganic salts other than carbonates, such as sodium sulfate, magnesium sulfate, magnesium hydride, potassium chloride, sodium chloride, potassium nitrate, sodium nitrate, sodium polyphosphate, ammonium chloride, iron sulfate, sodium phosphate, and sodium thiosulfate; excipients other than component (C), such as calcium silicate and glucose; disintegrants; medicinal components such as herbal medicines; pigments; fragrances; and the like. Furthermore, the bath additive of the present invention may also contain the aforementioned water-soluble polymer component (C). The total content of the above-mentioned other components in the bath additive is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, even more preferably 5% by mass or less, and even more preferably 2% by mass or less, from the viewpoint of facilitating the solidification of the composition, suppressing foaming of the bath water, and improving moldability.

[0063] <Dosage form, manufacturing method> From the viewpoint of improving handling, the bath additive of the present invention is preferably a solid bath additive. When a bath additive consists solely of the aforementioned solid bath composition, the dosage form of the bath additive is not particularly limited, but from the viewpoint of ease of handling during use, it is preferably in granular, briquette, or tablet form, with granular form being more preferable. In the case of briquette or tablet form, it may be formed into granules first and then into briquette or tablet form by known methods such as tableting, or it may be formed into briquette or tablet form without going through the granular state.

[0064] When the bath additive of the present invention contains the aforementioned organic acid and carbonate, it is preferable to mix the bath solid composition with the organic acid and carbonate. The preferred dosage form (product form) of the bath additive containing the organic acid and carbonate is a tablet. Tablets include compressed tablets and briquettes, and compressed tablets are more preferable from the viewpoint of moldability. Furthermore, when the bath additive of the present invention contains the aforementioned organic acid and carbonate, it is preferable to mix the granular bath solid composition with the organic acid, carbonate, and other components before molding. When the bath additive of the present invention is in the form of a tablet, briquette, or tablet, it can be manufactured using a press tablet press or briquette machine in accordance with conventional methods such as compression molding.

[0065] The bath additive of the present invention can be solidified while containing an oil, produces less foam in the bathwater (or foam after effervescence in the case of carbonated effervescent bath additives), dissolves slowly in the bathwater, and provides a good moisturizing feeling after bathing.

[0066] [Bath cosmetics] The bath cosmetic of the present invention contains the bath solid composition of the present invention described above. The bath cosmetic of the present invention may also contain components other than the bath solid composition described above, for example, water and a gelling agent. Preferably, the gelling agent is one or more selected from the group consisting of carrageenan, gelatin, agar, pectin, sodium carboxymethylcellulose, and xanthan gum. Examples of bath cosmetics containing ingredients other than the aforementioned solid bath composition include paste-like and gel-like substances that are applied to the skin while bathing.

[0067] When a bath cosmetic contains water, the water content in the bath cosmetic is preferably 15% by mass or more, more preferably 20% by mass or more, from the viewpoint of improving the feel when applying it to the skin in the bath. Furthermore, from the viewpoint of improving moldability, it is preferably 75% by mass or less, more preferably 65% ​​by mass or less, and even more preferably 55% by mass or less. Furthermore, if the bath cosmetic contains a gelling agent, the amount of gelling agent in the bath cosmetic is preferably 3% by mass or more, more preferably 5% by mass or more, from the viewpoint of improving moldability. It is also preferably 20% by mass or less, more preferably 15% by mass or less.

[0068] When the bath cosmetic contains components other than the bath solid composition, the amount of the bath solid composition in the bath cosmetic varies depending on the composition of the bath solid composition and the types of other components used, but is preferably 10% by mass or more and 95% by mass or less, more preferably 10% by mass or more and 80% by mass or less, even more preferably 10% by mass or more and 70% by mass or less, and even more preferably 10% by mass or more and 60% by mass or less.

[0069] <Other ingredients> The bath cosmetic composition of the present invention may include, as other components besides water and gelling agents, for example, nonionic surfactants or amphoteric surfactants other than component (B); alcohols other than component (A); vitamins; disinfectants; anti-inflammatory agents; preservatives; moisturizers such as glycerin; pearlescent agents; ceramides; fragrances; antioxidants; UV absorbers; plant extracts; medicinal components such as herbal medicines; colorants; excipients other than component (C), such as glucose; and the like. Furthermore, the bath cosmetic composition of the present invention may also contain the aforementioned water-soluble polymer component (C). The total content of the above-mentioned other ingredients in the bath cosmetic is preferably 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less, from the viewpoint of improving the feel when applied to the skin while bathing and from the viewpoint of improving moldability.

[0070] <Manufacturing method> The method for producing the bath cosmetic of the present invention is not particularly limited, and known methods can be employed. For example, it can be produced by mixing the bath solid composition with the aforementioned water, gelling agent, etc.

[0071] In the bath cosmetic of the present invention, the bath solid composition can maintain a solid state while containing an oily agent, has the property of dissolving slowly in bath water, and provides a good moisturizing feeling after bathing. [Examples]

[0072] The present invention will be described below with reference to examples, but the present invention is not limited to the scope of these examples.

[0073] Examples 1-19, Comparative Examples 1-10 (Production and Evaluation of Solid Bath Compositions) After mixing the components shown in Tables 1-4, the mixture was heated to melt it, and the molten mixture, kept warm at 60°C, was poured into aluminum cups with a diameter of 2 cm and a height of 1 cm. It was then allowed to cool and solidify at room temperature (25°C) to produce a solid bath composition. Furthermore, the appearance (whether or not it solidified), solubility in bath water, foaming of the bath water, and gel hardness of the bath solid composition were measured and evaluated using the method described below. The results are shown in Tables 1 to 4. Note that the content (mass %) of each component shown in Tables 1-4 all represent the active amount.

[0074] <Appearance (Can it be solidified?)> The appearance and surface condition of the solid bath composition produced by the above method were observed and evaluated according to the following criteria. A rating of "B" or higher was considered acceptable for the solidification evaluation of the bath additive. AA: Solidifies in one phase, with no oil seepage and a smooth texture. A: It solidifies in one phase, and there is a slight oil seepage, but it has a smooth texture at the same level as an AA rating. B: It has solidified in one phase, but there is some oil seepage, and oil gets on your fingers, but it is still at a usable level. C: It has solidified in phase 1, but there is oil seepage, the surface is sticky, and it is not at a practical level. D: It is not separated into two phases but is a single phase, and has not solidified. E: Separated into liquid and solid phases, or in a liquid state.

[0075] <Solubility in bath water> Approximately 5.5g of the molten mixture, manufactured using the method described above and kept warm at 60°C, was poured into a 2cm x 2cm x 1.5cm mold and allowed to cool and solidify at room temperature (25°C). The solubility of this mixture was evaluated according to the following criteria when applied to the skin by a specialist panelist in 150L of 40°C bath water. A rating of "B" or higher indicates that the mixture dissolves slowly in bath water and is considered acceptable. A: It dissolves slowly during use and spreads evenly. B: Dissolves faster than A during use, but spreads more evenly. C: It crumbles easily during use and cannot be spread evenly. D: When added to the bathwater, it immediately crumbles and cannot be spread. E: Does not dissolve in bath water

[0076] <Foaming of bathwater> The bath solid composition prepared by the above method was crushed to a size of 2 mm or less, and 0.5 g of it was added to 500 mL of 40°C bath water in a beaker and completely dissolved. Then, the mixture was stirred at 500 rpm for 30 seconds using a digital stirrer to create bubbles on the surface of the bath water. After standing for 3 minutes, the condition of the bath water surface (liquid surface) was visually observed and evaluated according to the following criteria. A rating of "C" or higher was considered acceptable. A: There are no bubbles on the liquid surface. B: There are a few bubbles around the rim of the beaker containing the bath water. C: Less than half of the liquid surface is covered with bubbles. D: The liquid surface is not completely covered, but more than half is covered with bubbles. E: The entire surface of the liquid is covered with bubbles.

[0077] <Gel hardness> The gel hardness of the bath solid composition produced by the above method was measured using a rheometer (FUDOH RHEO METER RTC-3010D-CW, manufactured by Rheotec Co., Ltd.) under the following conditions: measurement temperature: 25°C, measurement mode: UP, fixture used: No. 6 (Φ1mm), and penetration speed: 6cm / min. If the gel hardness is less than 5.0N, the bath solid composition has a good feel when applied to the skin, and if it is less than 3.0N, the feel is even better.

[0078] [Table 1]

[0079] [Table 2]

[0080] [Table 3]

[0081] [Table 4]

[0082] Details of the ingredients listed in the table are as follows. *1: Tri(caprylic / capric acid) glyceryl, manufactured by Kao Corporation in "Coconard MT" *2: Isopropyl myristate, manufactured by Kao Corporation as "Excepearl IPM" *3: Isopropyl palmitate, manufactured by Kao Corporation as "Excepearl IPP" *4: Liquid paraffin, "Highcall K-230" manufactured by Kaneda Co., Ltd. *5: POE(30) stearyl ether, EMALEX 630 manufactured by Nippon Emulsion Co., Ltd., freezing point 46°C *6: POE(20) behenyl ether, "EMALEX BHA20" manufactured by Nippon Emulsion Co., Ltd., melting point 52℃ *7: PEG(20) monostearate, EMALEX 820 manufactured by Nippon Emulsion Co., Ltd., melting point 40℃ *8: POE(160) sorbitan triisostearate, manufactured by Kao Corporation as "Leodol TW-IS399C", melting point 47℃ *9: POE(5) lauryl ether, EMALEX 705 manufactured by Nippon Emulsion Co., Ltd., melting point 8.4℃ *10 POE(40) sorbitol tetraoleate, manufactured by Kao Corporation as "Leodol 440V", freezing point -20℃ *11: Polyethylene glycol, manufactured by Kao Corporation, "K-PEG6000LA", molecular weight 7300-9300

[0083] Tables 1-3 show that the solid bath composition of this example is superior in terms of appearance, solubility in bath water, and low foaming of the bath water. In contrast, the solid bath composition of this comparative example shown in Table 4 showed inferior performance in one or more of the above evaluation items.

[0084] Examples 20-23, Comparative Examples 11-12 (Manufacturing and Evaluation of Carbonated Effervescent Bath Additives) The bath solid composition shown in Table 5 and the other components were mixed in the proportions indicated in the table. The mixture was then compressed and molded at a pressure of 5.0 N using a press tablet machine to produce 40 g tablets (tablet-type carbonated effervescent bath additives). Furthermore, the appearance of the tablets, the foaming of the bath water after the tablets have dissolved, and the effects of bathing can be observed using the method described below. We evaluated the skin feel. The results are shown in Table 5. Note that the content (mass %) of each component shown in Table 5 all represent the active amount.

[0085] <Appearance of the tablet> The appearance of the bath additive (tablets) manufactured by the above method was observed and evaluated according to the following criteria. A: There is no oil seepage, and the appearance is good. B: There is almost no oil seepage, and the appearance is good. C: There is some oil seepage, but the appearance is good. D: There is oil seepage, resulting in a defective appearance.

[0086] <Foaming of the bath water after the tablet has dissolved> One bath additive tablet manufactured by the above method was added to 150 L of bath water at 40°C to generate carbon dioxide gas. After the carbonation had finished, the condition of the bath water surface (liquid surface) was visually observed 10 minutes later and evaluated according to the following criteria. A: No bubbles on the liquid surface, or less than 5% of the liquid surface remains as bubbles. B: 5% to less than 50% of bubbles remain on the liquid surface. C: 50% to less than 90% of bubbles remain on the liquid surface. D: More than 90% of bubbles remain on the liquid surface.

[0087] <Skin feel after bathing> One bath additive tablet manufactured by the above method was added to 150L of bath water at 40°C, and a panel of experts bathed for 10 minutes. The skin feel (moisture level) after bathing was evaluated according to the following criteria. A: It is more moist than B. B: Moisturizing C: Not as moist as B, but still acceptable. D: Does not moisturize (same as plain hot water)

[0088] [Table 5]

[0089] Example 24 (Manufacturing and evaluation of bath cosmetics) Mix the bath solid composition of Example 8 with the other components listed in Table 6 in the proportions shown in the table. Then, 40g of a gel-like bath cosmetic was prepared. Furthermore, the appearance of the cosmetic, its solubility in bathwater, and the feel of the skin after bathing (moisture) were evaluated using the method described below. The results are shown in Table 6. Note that the content (mass %) of each component shown in Table 6 all represent the active amount.

[0090] <Appearance of bath cosmetics> The appearance of the bath cosmetic produced by the above method was observed and evaluated according to the following criteria. A: The bath solid composition remains undissolved in the gel. B: The bath solid composition is partially dissolved in the gel, but still exists as a solid. C: The bath solid composition is completely dissolved in the gel.

[0091] <Solubility in bath water> The solubility of the bath solid composition contained in the gel (cosmetic) was evaluated according to the following criteria when a professional panelist applied the bath cosmetic manufactured by the above method to the skin in 150 L of 40°C bath water. A: As the gel (cosmetic) dissolves, the bath solid composition slowly dissolves during use and spreads evenly. B: The bath solid composition dissolves faster than A during use as the gel (cosmetic) dissolves, but it spreads evenly. C: The bath solid composition quickly disintegrates during use as the gel (cosmetic) dissolves, making it impossible to spread evenly. D: The gel (cosmetic) dissolves, but the solid bath composition does not dissolve in the bath water.

[0092] <Skin feel after bathing (moisture level)> The bath cosmetic produced by the above method was added to 150L of bath water at 40°C, and expert panelists bathed for 10 minutes. The skin feel (moisture level) after bathing was evaluated according to the following criteria. A: It is more moist than B. B: Moisturizing C: Not as moist as B, but still acceptable. D: Does not moisturize (same as plain hot water)

[0093] [Table 6]

[0094] *12: Carrageenan, manufactured by MRC Polysaccharides, "Soagina LX22K"

[0095] Example 25 (Observation of bath solid composition using a scanning electron microscope (SEM)) 16.7 parts by mass of diisopropyl adipate (manufactured by Nikko Chemicals Co., Ltd.) as component (A) and 83.3 parts by mass of polyoxyethylene (20) stearyl ether (「EMALEX 620」manufactured by Nippon Emulsion Co., Ltd., average number of moles of added EO: 20, freezing point: 44°C) as component (B) were used. After mixing the two components, they were heated and melted, and the molten mixture kept at 60°C was poured into an aluminum cup with a diameter of 2 cm and a height of 1 cm, and allowed to cool and solidify at room temperature (25°C) to produce a solid composition for bath use. The result of evaluating the appearance (possibility of solidification) by the above method was 「A」. Regarding the state of component (B) in the solid composition for bath use having the above composition, SEM observation was carried out by the method described below.

[0096] <Preparation of Sample for SEM Observation> The above molten mixture was poured into a screw tube with a diameter of 2 cm up to a height of about 3 cm, allowed to cool and solidify at room temperature (25°C) to produce a solid composition for bath use for sample preparation. The solid composition in the screw tube was cut out using a measuring cylinder and a spatula, and further cut using a razor to prepare a sample of about 2 mm × 4 mm × 4 mm. OCT compound was attached to a grooved SEM sample stage made of copper, and the above sample was placed thereon such that the surface of 2 mm × 4 mm was upward, and immersed in liquid nitrogen for rapid freezing. Regarding the frozen sample, after face-milling was performed using a cryomicrotome under the conditions described below, the portion protruding from the sample stage was cut off using a razor. Next, about 3 mL of n-hexane was put into a screw tube with a diameter of 2 cm and a volume of 10 mL, cooled to such an extent that it was not frozen in the cryomicrotome, and then the sample after face-milling was put in. It was taken out from the cryomicrotome and returned to room temperature, and after about 24 hours, the hexane was replaced, and it was allowed to stand for 4 days so that the face-milled part did not touch the wall surface of the screw tube. After standing, the sample was taken out and naturally dried for about 5 minutes to volatilize the hexane. By the above operations, a sample for SEM observation from which component (A) in the solid composition for bath use was removed was prepared. (Cryomicrotome Conditions) Apparatus: EM UC7 Cryo Unit FC7 (manufactured by Leica) Temperature: -120 °C for both the atmosphere, knife, and sample Knife used: Diamond knife cryotrim 45° (manufactured by DiATOME) Cutting conditions: Speed 1.0 mm / sec, feed width 50 nm

[0097] <SEM Observation> The obtained SEM observation sample was placed on a SEM sample stage with OCT compound attached, immersed in liquid nitrogen for rapid freezing, and introduced into the Cryo-SEM for observation under the following conditions. (SEM Observation Conditions) Device: JSM-7600F (manufactured by JEOL) Cryo system: PP3010T (manufactured by Quorum) Anti-contamination trap temperature: -180 °C Sample temperature / sublimation conditions: -160 °C at introduction → observation before sublimation → sublimation (-80 °C for 20 minutes, inside the prep stage) → observation (-160 °C) Acceleration voltage: 1 kV Irradiation current: No8 Working distance: 12.0 mm Detector: LEI (Lower Secondary Electron Image) Deposition: None

[0098] The SEM images are shown in Figure 1. From Figure 1, it was confirmed that the component (B) (polyoxyethylene (20) stearyl ether) in the solid composition for bath forms molecular crystals, and the structure is lattice-like as the plate-like structures (crystals) are assembled. Also, as described above, the appearance evaluation result of the solid composition for bath in Example 25 is "A", and since component (A) hardly exudes, it is considered that component (A) is supported by component (B).

[0099] Example 26 (Small-angle X-ray scattering (SAXS) measurement of the solid composition for bath) Component (A) consisted of 50.0 parts by mass of diisopropyl adipate (manufactured by Nikko Chemicals Co., Ltd.), and component (B) consisted of 50.0 parts by mass of polyoxyethylene (20) behenyl ether ("EMALEX BHA20" manufactured by Nippon Emulsion Co., Ltd., average number of EO added moles: 20, melting point: 52°C). After mixing both components, the mixture was heated to melt, and the molten mixture, kept warm at 60°C, was poured into an aluminum cup with a diameter of 2 cm and a height of 1 cm. The mixture was allowed to cool and solidify at room temperature (25°C) to produce a solid bath composition. The result of the appearance evaluation (whether or not it solidified) using the above method was "A". Furthermore, the obtained bath solid composition was packed into a 2cm × 2cm × 2mm (thickness) high-viscosity paste cell to prepare a measurement sample (Sample 1). Separately, a solid component (B) was prepared as a control measurement sample (Sample 2) using the same method. SAXS measurements were performed on sample 1 and sample 2 using a small-angle X-ray analyzer (Anton Paar "SAXSessMC2") under the following conditions: detector: imaging plate (IP), cell: paste cell, measurement time: 3-10 minutes, measurement temperature: 25°C. The measurement chart is shown in Figure 2. From Figure 2, the peak positions of 2θ in sample 1 are 1:2:3:4, suggesting that component (B) (polyoxyethylene (20) behenyl ether) forms a lamellar molecular crystal in the bath solid composition. Furthermore, since the peak position of 2θ is the same in sample 1 and sample 2, and there is no change in angle with or without oil (A), it is considered that oil (A) is not miscible with component (B) in the bath solid composition, but rather is supported in the voids of the crystals formed by component (B). [Industrial applicability]

[0100] According to the present invention, it is possible to provide a solid bath composition that contains an oily agent, can be solidified, dissolves slowly in bath water, and produces less foam in the bath water.

Claims

1. The following components (A) and (B): (A) Oil (B) Nonionic surfactants with a melting point of 25°C or higher A solid bath composition containing, A bath solid composition wherein the content of component (B) in the bath solid composition is 20% by mass or more, and the mass ratio of component (A) to component (B), (A) / (B), is 0.20 or more.

2. The bath solid composition according to claim 1, wherein the component (B) is one or more selected from the group consisting of polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene sorbitan fatty acid ester.

3. The bath solid composition according to claim 1 or 2, wherein the total content of component (A) and component (B) is 30% by mass or more.

4. A bath additive containing the bath solid composition described in any one of claims 1 to 3.

5. The bath additive according to claim 4, further containing an organic acid and a carbonate.

6. A bath cosmetic containing the bath solid composition described in any one of claims 1 to 3.

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