Solid bath agent

Abstract

To provide a solid bath agent in which carbon dioxide effervescence in hot water is sustained for a long time and bubble spreading over the hot water surface is favorable.SOLUTION: A solid bath agent comprises the following components (A), (B), and (C): (A) a carbonate, (B) an organic acid, and (C) a nonionic surfactant having an HLB of 10 or more, in which the content of the component (C) in the solid bath agent is 0.10 mass% or more and 5.5 mass% or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a solid bath additive. [Background technology]

[0002] Bath additives containing carbonates and organic acids are known to generate carbon dioxide bubbles in the bath, providing a warming sensation and promoting blood circulation, as well as allowing the enjoyment of the effervescent sensation of carbon dioxide.

[0003] For example, Patent Document 1 discloses that a solid bubble bath composition contains a specific surfactant and a specific oily component in specific proportions, and the total amount of carbonate and acid is 50% by weight or more. When the composition is poured into bathwater, creamy bubbles spread over the surface of the bathwater, allowing the user to enjoy the feel of bubbles on the surface of the bathwater while bathing, and also providing a moist and smooth feeling to the skin after bathing. Patent Document 2 discloses that a solid foaming bath agent composition contains a specific amount of a nonionic surfactant having a specific HLB value, an organic acid, and a carbonate, and is used so that the concentration of the nonionic surfactant in bath water is a specific amount. The composition adjusts the foaming behavior of the bath agent, inhibits it from floating to the water surface, and increases the underwater foaming time / total dissolution time, thereby enabling carbon dioxide gas to be efficiently dissolved in bath water. Patent Document 3 discloses that a powdered bubble bath composition containing a granule containing a foaming surfactant, an organic acid, and a water-soluble polymer, and a carbonate containing a specific amount of a dialkali metal carbonate, can achieve both excellent cleansing ability and a good moisturizing feeling on the skin while maintaining the good usability of a bubble bath. Patent Document 4 discloses that a bath agent composition containing an organic acid, a carbonate, a nonionic surfactant having a specific HLB value, an anionic surfactant, and a thickener, in which the mass ratio of the nonionic surfactant, the anionic surfactant, and the thickener is equal to or less than a specific value, generates fine bubbles on the surface of the bath water, and can maintain the bubbles well, increasing the persistence of the bubbles and improving the feel of the bubbles on the skin. Patent Document 5 also discloses that a foaming bath additive containing specific amounts of an organic acid, a carbonate, and an amino acid surfactant may be in the form of a briquette, and that it produces fine bubbles, maintains foaming in water for a long time, prevents bubbles from remaining on the surface of the water once they have been produced, and further reduces irritation to the skin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-12443 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-190190 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-131739 [Patent Document 4] Japanese Patent Application Laid-Open No. 2015-113321 [Patent Document 5] Japanese Patent Publication No. 2021-134149 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to improve the effervescent sensation during bathing with a carbon dioxide gas effervescent bath additive, it is usually effective to increase the solubility of the bath additive in hot water and increase the amount of carbon dioxide gas effervescent in a short period of time. In response to this, in recent years, there has been a demand for the development of bath additives that can provide a greater relaxation effect by extending the time that carbon dioxide gas bubbles in the water, and that further provide a pleasant feel of bubbles that spread well on the surface of the water.From the viewpoint of achieving a greater relaxation effect and providing the tactile sensation of bubbles produced by carbon dioxide gas bubbles as a skin stimulus, it is preferable that the bath additives foam carbon dioxide in the water, rather than floating to the surface, and that the foaming time be long.

[0006] The technologies disclosed in Patent Documents 1 to 5 have investigated either extending the time that carbon dioxide gas bubbles in the water or improving the spread of bubbles on the water surface in carbon dioxide gas-effervescent bath additives, but have not yet achieved a bath additive that both extends the time that carbon dioxide gas bubbles in the water and provides good spread of bubbles on the water surface. For example, powdered bath additives such as those disclosed in Patent Document 3 dissolve quickly in water, making it difficult to extend the time that carbon dioxide gas bubbles in the water.

[0007] The present invention relates to a solid bath additive that produces carbon dioxide gas bubbles for a long time in hot water and spreads bubbles well over the surface of the water. [Means for solving the problem]

[0008] The present inventors have discovered that a solid bath additive containing a carbonate, an organic acid, and a predetermined amount of a nonionic surfactant with an HLB of 10 or more can solve the above problems. That is, the present invention relates to the following. [1] The following ingredients (A), (B), and (C): (A) one or more selected from the group consisting of bicarbonates and carbonates (B)Organic acid (C) Nonionic surfactants with HLB of 10 or more A solid bath additive comprising the above component (C), wherein the content of the component (C) in the solid bath additive is 0.10% by mass or more and 5.5% by mass or less. [Effects of the Invention]

[0009] According to the present invention, a solid bath additive can be provided which can provide a higher relaxation effect because of the long time that carbon dioxide gas bubbles in the hot water, and further, can provide an enjoyable feeling of bubbles because the bubbles spread well on the surface of the hot water. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Solid bath additives] The solid bath additive of the present invention (hereinafter also referred to simply as "the bath additive of the present invention") comprises the following components (A), (B), and (C): (A) Carbonate (B)Organic acid (C) Nonionic surfactants with HLB of 10 or more The solid bath additive contains the component (C), and the content of the component (C) in the solid bath additive is 0.10% by mass or more and 5.5% by mass or less. In the present invention, the term "solid bath additive" refers to a bath additive that is solid at 25°C, excluding powder or granule forms, and is preferably a tablet-type bath additive.

[0011] By using the bath additive of the present invention as described above, the carbon dioxide gas bubbles in the bath for a long time and the bubbles spread well over the surface of the bath. The reason for this is not clear, but it is thought to be as follows. Components (A) and (B) are carbon dioxide gas-generating components, and when a solid bath additive containing components (A) and (B) is added to hot water, the two react to generate carbon dioxide gas. Because the bath additive of the present invention is a solid bath additive, it dissolves slowly in hot water, allowing for a longer period of time for carbon dioxide gas to bubble in the water. The nonionic surfactant component (C) is believed to be effective in causing bubbles generated by the reaction of components (A) and (B) to rise to the surface of the bath water, and to spread the bubbles over the entire surface of the bath water due to the surfactant's foaming and foam retention effects. Here, if the HLB value of component (C) is equal to or greater than a predetermined value, it is believed that excessive carbon dioxide gas generated in the bath water is prevented from rising to the surface of the bath water, thereby lengthening the time for carbon dioxide gas to bubble in the bath water. Furthermore, if the content of component (C) in the solid bath additive is within a predetermined range, it is believed that the time for carbon dioxide gas to bubble in the bath water can be extended while ensuring good foam spreading over the bath water surface.

[0012] <Component (A): Carbonate> The bath additive of the present invention contains a carbonate as component (A), which acts as a carbonated foaming component by reacting with component (B). Examples of component (A) include alkali metal bicarbonates such as sodium bicarbonate and potassium bicarbonate; dialkali metal carbonates such as sodium carbonate and potassium carbonate; and alkaline earth metal carbonates such as calcium carbonate and magnesium carbonate; and one or more of these can be used. From the viewpoint of improving the carbon dioxide gas effervescence properties of the bath additive and improving the duration of carbon dioxide gas effervescence in the bathwater, component (A) preferably contains one or more selected from the group consisting of alkali metal bicarbonates and dialkali metal carbonates, more preferably contains one or more selected from the group consisting of sodium bicarbonate and sodium carbonate, and even more preferably contains sodium bicarbonate and sodium carbonate.

[0013] When component (A) contains an alkali metal bicarbonate, the content of the alkali metal bicarbonate in component (A) is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 45% by mass or more, from the viewpoint of improving the carbon dioxide gas foaming properties of the bath additive and improving the carbon dioxide gas foaming time in the hot water. Also, the content is 100% by mass or less, preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less, still more preferably 60% by mass or less, and even more preferably 50% by mass or less.

[0014] When component (A) contains a dialkali metal carbonate, the content of the dialkali metal carbonate in component (A) is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more, from the viewpoint of improving the carbon dioxide gas foaming properties of the bath additive and improving the carbon dioxide gas foaming time in the hot water. Also, it is 100% by mass or less, preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less, and even more preferably 60% by mass or less.

[0015] When component (A) contains an alkali metal bicarbonate and a dialkali metal carbonate, the mass ratio [alkali metal bicarbonate / dialkali metal carbonate] is preferably 0.50 or more, more preferably 0.70 or more, even more preferably 0.80 or more, still more preferably 0.90 or more, from the viewpoint of improving the carbon dioxide gas foaming properties of the bath additive and improving the carbon dioxide gas foaming time in the hot water, and is also preferably 2.0 or less, more preferably 1.5 or less, even more preferably 1.2 or less, and still more preferably 1.1 or less.

[0016] <Component (B): Organic acid> The bath additive of the present invention contains an organic acid as component (B). Component (B) acts as a carbonic acid-producing component by reacting with component (A). However, in this specification, component (B) does not include amino acids.

[0017] Component (B) is preferably a low-molecular-weight compound from the viewpoints of improving the carbon dioxide gas foaming properties of the bath additive, extending the time for carbon dioxide gas foaming in the bath, and improving the spread of bubbles on the bath surface. The molecular weight of the organic acid of component (B) is preferably 1,000 or less, more preferably 800 or less, even more preferably 600 or less, still more preferably 500 or less, still more preferably 400 or less, and still more preferably 300 or less, and from the viewpoint of suppressing volatility, it is preferably 80 or more, more preferably 100 or more.

[0018] Component (B) may be a carboxylic acid compound, an organic sulfonic acid compound, or an organic phosphoric acid compound. From the viewpoint of improving the carbon dioxide gas foaming ability of the bath additive and improving the carbon dioxide gas foaming time in the hot water, a carboxylic acid compound is preferred. The carboxylic acid compound may be any compound having at least one carboxy group, but from the viewpoint of obtaining a solid bath additive and improving the time for carbon dioxide gas to bubble in the bath, a compound that is solid at 25°C is preferred. Furthermore, from the viewpoint of improving the carbon dioxide gas effervescence properties of the bath additive and improving the time for which carbon dioxide gas effervescence occurs in the bath, polycarboxylic acids having two or more carboxy groups are preferred among the carboxylic acid compounds.

[0019] Examples of the carboxylic acid compound include aliphatic carboxylic acids, aromatic carboxylic acids, and heterocyclic carboxylic acids. Examples of aliphatic carboxylic acids include aliphatic polycarboxylic acids having no hydroxy group, such as oxalic acid, fumaric acid, succinic acid, glutaric acid, and adipic acid; and aliphatic hydroxy polycarboxylic acids, such as malic acid, tartaric acid, and citric acid. Examples of aromatic carboxylic acids include benzoic acid, salicylic acid, and phthalic acid. Examples of heterocyclic carboxylic acids include pyrrolidone carboxylic acid.

[0020] The component (B) can be used alone or in combination of two or more. Among the above, from the viewpoints of improving the carbon dioxide gas foaming properties of the bath additive, improving the time for which carbon dioxide gas foams in the water, and improving the spread of bubbles on the water surface, component (B) preferably contains an aliphatic carboxylic acid, preferably contains an aliphatic polycarboxylic acid, more preferably contains one or more selected from the group consisting of aliphatic polycarboxylic acids having no hydroxy groups and aliphatic hydroxypolycarboxylic acids, even more preferably contains an aliphatic polycarboxylic acid having no hydroxy groups, even more preferably contains one or more selected from the group consisting of fumaric acid, succinic acid, tartaric acid, and adipic acid, even more preferably contains one or more selected from the group consisting of fumaric acid, tartaric acid, and succinic acid, and even more preferably contains fumaric acid.

[0021] When component (B) contains fumaric acid, the content of fumaric acid in component (B) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, and even more preferably 90% by mass or more, but 100% by mass or less, from the viewpoint of improving the carbon dioxide gas bubbling time in hot water.

[0022] <Component (C): Nonionic surfactant with HLB of 10 or higher> The bath additive of the present invention contains, as component (C), a nonionic surfactant with an HLB of 10 or higher. In this specification, component (C) may contain two or more nonionic surfactants, but each of the nonionic surfactants constituting component (C) must have an HLB of 10 or higher. The content of component (C) in the bath additive of the present invention refers to the total amount of nonionic surfactants each having an HLB of 10 or higher. HLB (Hydrophile-Lypophile Balance) is a value that indicates the affinity of a surfactant for water and oil, and can be calculated using the following formula by the Griffin method. HLB = 20 × [(molecular weight of hydrophilic group contained in surfactant) / (molecular weight of surfactant)] Examples of the above-mentioned "hydrophilic group" include a hydroxy group and an ethyleneoxy group.

[0023] Examples of the nonionic surfactant used as component (C) include polyoxyethylene alkyl ethers, polyoxyethylene alkenyl ethers, sucrose fatty acid esters, polyoxyethylene fatty acid esters, polyglyceryl alkyl ethers, fatty acid polyglyceryl, alkyl glucosides, polyoxyethylene alkylamines, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and polyoxyethylene hydrogenated castor oil, and one or more of these can be used.

[0024] Of the nonionic surfactants, the alkyl groups in polyoxyethylene alkyl ethers, polyglyceryl alkyl ethers, alkyl glucosides, and polyoxyethylene alkylamines, the alkenyl groups in polyoxyethylene alkenyl ethers, and the fatty acids in sucrose fatty acid esters, polyoxyethylene fatty acid esters, fatty acid polyglyceryls, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters preferably have 8 to 22 carbon atoms, more preferably 10 to 22 carbon atoms, even more preferably 12 to 20 carbon atoms, and even more preferably 14 to 20 carbon atoms, from the viewpoint of improving the time that the bath additives allow carbon dioxide gas to bubble in the water and improving the spread of bubbles on the water surface.

[0025] Among the nonionic surfactants, the average number of moles of ethylene oxide added (hereinafter referred to as "average number of moles of EO added") in polyoxyethylene alkyl ethers, polyoxyethylene alkenyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbit fatty acid esters, and polyoxyethylene hydrogenated castor oil is, from the viewpoint of improving the time that the bath additives bubble carbon dioxide in hot water and improving the spread of bubbles on the surface of the water, preferably 2 or more, more preferably 3 or more, even more preferably 5 or more, and is preferably 150 or less, more preferably 80 or less, even more preferably 60 or less. Note that the average number of moles of EO added is a number average value.

[0026] Among the above, from the viewpoint of improving the time that the bath additives produce carbon dioxide gas bubbles in the water and improving the spread of bubbles on the water surface, component (C) preferably contains one or more selected from the group consisting of polyoxyethylene alkyl ethers, sucrose fatty acid esters, alkyl glucosides, and polyoxyethylene sorbite fatty acid esters.

[0027] Specific examples of polyoxyethylene alkyl ethers include polyoxyethylene lauryl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene behenyl ether, etc. Among these, from the viewpoint of improving the time that the bath additive produces carbon dioxide gas bubbles in the bath and improving the spread of bubbles on the surface of the bath, preferred are one or more selected from the group consisting of polyoxyethylene lauryl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, and polyoxyethylene stearyl ether, more preferred are one or more selected from the group consisting of polyoxyethylene lauryl ether and polyoxyethylene cetyl ether, and even more preferred is polyoxyethylene cetyl ether.

[0028] Examples of sucrose fatty acid esters include esters of sucrose (sucrose) and saturated or unsaturated fatty acids preferably having 8 to 22 carbon atoms, more preferably 10 to 22 carbon atoms, even more preferably 12 to 20 carbon atoms, and even more preferably 14 to 20 carbon atoms. Sucrose fatty acid esters can be appropriately selected from monoesters, diesters, triesters, tetraesters, pentaesters, hexaesters, heptaesters, and octaesters, each having an HLB of 10 or higher. Among these, from the viewpoint of functioning as a nonionic surfactant with an HLB of 10 or higher, the sucrose fatty acid ester preferably contains a monoester or diester as the main component, more preferably a monoester as the main component. Here, the term "main component" refers to a component that accounts for 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, of the total components, but not more than 100% by mass. Specific examples of sucrose fatty acid esters include sucrose myristate, sucrose pentadecylate, sucrose palmitate, sucrose palmitoleate, sucrose margadelate, sucrose stearate, sucrose oleate, sucrose arachidate, sucrose erucate, sucrose behenate, etc. Among these, from the viewpoints of improving the time that the bath additive produces carbon dioxide gas in the bath, improving the spread of bubbles on the bath surface, and availability, preferred are one or more selected from the group consisting of sucrose myristate, sucrose palmitate, and sucrose stearate, more preferred are one or more selected from the group consisting of sucrose palmitate and sucrose stearate, and even more preferred is sucrose palmitate.

[0029] Specific examples of alkyl glucosides include decyl glucoside, lauryl glucoside, cetyl glucoside, stearyl glucoside, etc. Among these, from the viewpoint of improving the time that the bath additive produces carbon dioxide gas bubbles in the bath and improving the spread of bubbles on the surface of the bath, one or more selected from the group consisting of lauryl glucoside, cetyl glucoside, and stearyl glucoside is preferred, and lauryl glucoside is more preferred.

[0030] Specific examples of polyoxyethylene sorbitol fatty acid esters include polyoxyethylene sorbitol mono-, di-, tri-, or tetra-laurate, polyoxyethylene sorbitol mono-, di-, tri-, or tetra-oleate, polyoxyethylene sorbitol mono-, di-, tri-, or tetra-stearate, etc. Among these, polyoxyethylene sorbitol tetraoleate is preferred from the viewpoints of improving the time that the bath additive produces carbon dioxide bubbles in the water and improving the spread of bubbles on the water surface.

[0031] One or more types of component (C) can be used. Among the above, from the viewpoint of improving the time that the bath additives produce carbon dioxide gas bubbles in the water and improving the spread of bubbles on the water surface, component (C) more preferably contains one or more selected from the group consisting of polyoxyethylene alkyl ethers, sucrose fatty acid esters, and polyoxyethylene sorbite fatty acid esters, even more preferably contains sucrose fatty acid esters, even more preferably contains one or more selected from the group consisting of sucrose palmitate and sucrose stearate, and even more preferably contains sucrose palmitate.

[0032] In addition, from the viewpoint of maintaining an appropriate length of time for the bath additive to bubble carbon dioxide gas in the water and improving the spread of bubbles on the water surface, it is preferable that component (C1): a nonionic surfactant with an HLB of 14 or higher. If the carbon dioxide gas effervescence time of bath additives is too long, the amount of foam produced per unit time generally decreases, and the foaming effect may not be sufficient. It is also known that when the same pleasant tactile sensation is repeated, the pleasant sensation diminishes with habituation and the comfort level drops to zero within about 20 minutes (e.g., Triscoli c (2017) Biol Psychol 128, pp. 71-81). Therefore, it is preferable that the carbon dioxide gas effervescence time of bath additives in the water is not excessively long. Furthermore, from the viewpoint of maintaining an appropriate length of time for the bath additive to bubble carbon dioxide gas in the water, improving the spread of bubbles on the water surface, and improving the release of fragrance while bathing, it is more preferable for the bath additive to contain component (C1): a nonionic surfactant with an HLB of 14 or more, and component (C2): a nonionic surfactant with an HLB of 10 or more but less than 14. When component (C) contains components (C1) and (C2), the fragrance components are solubilized or emulsified, which is thought to further improve the fragrance release during bathing.

[0033] (Component (C1): Nonionic surfactant with HLB of 14 or higher) The HLB of component (C1) is preferably 14.5 or more, more preferably 15 or more, even more preferably 15.5 or more, from the viewpoint of maintaining an appropriate length of time for carbon dioxide gas bubbling in the bathwater of the bath additive and improving the spread of bubbles on the surface of the water, and is also preferably 20 or less, more preferably 19 or less, even more preferably 18 or less, and even more preferably 17.5 or less.

[0034] Specific examples of nonionic surfactants used as component (C1) include the same surfactants as those exemplified as component (C), preferably containing one or more surfactants selected from the group consisting of polyoxyethylene alkyl ethers, sucrose fatty acid esters, alkyl glucosides, and polyoxyethylene sorbite fatty acid esters, more preferably containing one or more surfactants selected from the group consisting of polyoxyethylene alkyl ethers, sucrose fatty acid esters, and alkyl glucosides, even more preferably containing one or more surfactants selected from the group consisting of polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, sucrose palmitate, sucrose stearate, and lauryl glucoside, even more preferably containing one or more surfactants selected from the group consisting of sucrose palmitate and sucrose stearate, and even more preferably containing sucrose palmitate.

[0035] The content of component (C1) in component (C) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, and even more preferably 85% by mass or more, from the viewpoint of maintaining a suitable length of time for the bath additive to bubble carbon dioxide gas in the hot water and improving the spread of bubbles on the hot water surface. It is also 100% by mass or less, and from the viewpoint of maintaining a suitable length of time for the bath additive to bubble carbon dioxide gas in the hot water, improving the spread of bubbles on the hot water surface, and improving the release of fragrance during bathing, it is preferably 99% by mass or less, more preferably 98% by mass or less, even more preferably 96% by mass or less, and even more preferably 95% by mass or less.

[0036] (Component (C2): Nonionic surfactant with HLB of 10 or more and less than 14) The HLB of component (C2) is preferably 10.2 or more, more preferably 10.4 or more, from the viewpoints of improving the time that the bath additive produces carbon dioxide gas in the bath, improving the spread of bubbles on the surface of the water, and improving the release of fragrance while bathing, and is also preferably 13.5 or less, more preferably 13 or less, even more preferably 12 or less, and even more preferably 11.5 or less.

[0037] Specific examples of nonionic surfactants used as component (C2) include the same surfactants as those exemplified as component (C), preferably containing one or more surfactants selected from the group consisting of polyoxyethylene alkyl ethers, sucrose fatty acid esters, alkyl glucosides, and polyoxyethylene sorbitol fatty acid esters, more preferably containing one or more surfactants selected from the group consisting of polyoxyethylene alkyl ethers, sucrose fatty acid esters, and polyoxyethylene sorbitol fatty acid esters, even more preferably containing one or more surfactants selected from the group consisting of polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, sucrose palmitate, sucrose stearate, and polyoxyethylene sorbitol tetraoleate, and even more preferably containing one or more surfactants selected from the group consisting of polyoxyethylene cetyl ether, sucrose palmitate, sucrose stearate, and polyoxyethylene sorbitol tetraoleate.

[0038] When component (C) contains component (C1) and component (C2), component (C1) and component (C2) may be the same type of nonionic surfactant differing only in the number of hydrophilic groups, or may be different types of nonionic surfactants. From the viewpoint of improving the time that the bath additive produces carbon dioxide gas bubbles in the water, improving the spread of bubbles on the water surface, and improving the release of fragrance while bathing, preferably, at least one of component (C1) and component (C2) contains a sucrose fatty acid ester, more preferably, at least one of component (C1) and component (C2) contains one or more selected from the group consisting of sucrose palmitate and sucrose stearate, even more preferably, at least one of component (C1) and component (C2) contains sucrose palmitate, and even more preferably, component (C1) contains sucrose palmitate.

[0039] Furthermore, when component (C) contains component (C1) and component (C2), it is even more preferable that component (C1) contains sucrose palmitate and component (C2) contains one or more selected from the group consisting of sucrose stearate, polyoxyethylene cetyl ether, and polyoxyethylene sorbitan tetraoleate.

[0040] When component (C) comprises component (C1) and component (C2), the mass ratio of component (C1) to component (C2) [(C1) / (C2)] is preferably 3.0 or more, more preferably 5.0 or more, even more preferably 10 or more, still more preferably 12 or more, from the viewpoints of improving the time that the bath additive produces carbon dioxide gas bubbles in the water, improving the spread of bubbles on the water surface, and improving the release of fragrance while bathing, and is also preferably 90 or less, more preferably 70 or less, even more preferably 50 or less, and still more preferably 30 or less.

[0041] <Average HLB of component (C)> The average HLB of component (C) contained in the bath additive of the present invention is preferably 14 or more, more preferably 14.5 or more, even more preferably 15 or more, and even more preferably 15.5 or more, from the viewpoint of improving the time that the bath additive produces carbon dioxide gas bubbles in the water and improving the spread of bubbles on the water surface; and is also preferably 20 or less, more preferably 19 or less, even more preferably 18 or less, even more preferably 17.5 or less, even more preferably 17 or less, even more preferably 16.5 or less, even more preferably 16 or less, and even more preferably 15.8 or less. Here, "average HLB of component (C)" means the HLB of the nonionic surfactant itself when only one nonionic surfactant with an HLB of 10 or more is used as component (C), and means the weighted average value of the HLBs of the two or more nonionic surfactants when two or more nonionic surfactants with an HLB of 10 or more are used as component (C).

[0042] <Component (C'): Nonionic surfactant other than component (C)> The bath additive of the present invention may further contain, as component (C'), a nonionic surfactant other than component (C). Component (C') is not particularly limited as long as it is a nonionic surfactant with an HLB of less than 10, and examples thereof include the compounds exemplified above as component (C) that have an HLB of less than 10.

[0043] However, from the viewpoint of improving the time that the bath additives produce carbon dioxide bubbles in the water, improving the spread of bubbles on the water surface, and improving the release of fragrance while bathing, the content of component (C') in the bath additives of the present invention is preferably 5% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less, still more preferably 0.1% by mass or less, even more preferably 0.01% by mass or less, and still more preferably 0% by mass.

[0044] <Average HLB of all nonionic surfactants> Furthermore, the average HLB of all nonionic surfactants contained in the bath additive of the present invention is preferably 14 or more, more preferably 14.5 or more, even more preferably 15 or more, and even more preferably 15.5 or more, from the viewpoint of improving the time that the bath additive produces carbon dioxide gas in the water and improving the spread of bubbles on the water surface, and is also preferably 20 or less, more preferably 19 or less, even more preferably 18 or less, even more preferably 17.5 or less, even more preferably 17 or less, even more preferably 16.5 or less, even more preferably 16 or less, and even more preferably 15.8 or less. Here, "average HLB of all nonionic surfactants" means the weighted average value of the HLB of all nonionic surfactants (i.e., component (C) and component (C')) contained in the solid bath additive of the present invention.

[0045] <Other ingredients> The bath additive of the present invention may contain other components besides the components (A), (B), (C), and (C') as appropriate, provided that the purpose of the present invention is not impaired. Examples of such components include inorganic salts other than component (A), such as sodium sulfate, magnesium sulfate, magnesium oxide, potassium chloride, sodium chloride, potassium nitrate, sodium nitrate, sodium polyphosphate, sodium metaphosphate, ammonium chloride, ferrous sulfate, sodium phosphate, and sodium thiosulfate; amino acids such as glycine; water-soluble polymers such as polyethylene glycol and dextrin; excipients such as calcium silicate and glucose; opacifiers such as titanium oxide; oils; higher alcohols; disintegrating agents; medicinal ingredients such as herbal medicines; colorants; and fragrances. Among the above, the bath additive of the present invention preferably contains one or more selected from the group consisting of inorganic salts other than component (A), amino acids, water-soluble polymers, excipients, and fragrances, and more preferably contains one or more selected from the group consisting of magnesium sulfate, magnesium oxide, glycine, water-soluble polymers, excipients, and fragrances.

[0046] The bath additive of the present invention may also contain one or more ionic surfactants selected from the group consisting of anionic surfactants, cationic surfactants, and amphoteric surfactants, provided that the effects of the present invention are not impaired. However, from the viewpoint of improving the time that the bath additive generates carbon dioxide gas in the bathwater and improving the spread of bubbles on the surface of the bathwater, the content of the ionic surfactant in the bath additive of the present invention is preferably 5% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less, still more preferably 0.1% by mass or less, still more preferably 0.01% by mass or less, and even more preferably 0% by mass.

[0047] <Content> The content of each component in the bath additive of the present invention is preferably within the following ranges. The content of component (A) in the solid bath additive is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 35% by mass or more, from the viewpoint of improving the carbon dioxide gas foaming ability of the bath additive and improving the time for carbon dioxide gas foaming in the hot water, and is preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 45% by mass or less.

[0048] The content of component (B) in the solid bath additive is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 35% by mass or more, and even more preferably 40% by mass or more, from the viewpoints of improving the bath additive's carbon dioxide gas foaming properties, improving the time for carbon dioxide gas foaming in the water, and improving the spread of bubbles on the water surface, and is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 45% by mass or less.

[0049] The total content of components (A) and (B) in the solid bath additive is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, still more preferably 70% by mass or more, and even more preferably 75% by mass or more, from the viewpoints of improving the carbon dioxide gas foaming properties of the bath additive, extending the time for carbon dioxide gas foaming in the hot water, and improving the spread of bubbles on the hot water surface. Also, the total content is 94.5% by mass or less, and from the viewpoints of moldability of the solid bath additive and improving the flexibility in blending other functional ingredients, it is preferably 90% by mass or less, more preferably 85% by mass or less.

[0050] The content of component (C) in the solid bath additive is 0.10% by mass or more, preferably 0.20% by mass or more, more preferably 0.30% by mass or more, even more preferably 0.50% by mass or more, still more preferably 0.75% by mass or more, still more preferably 0.90% by mass or more, and still more preferably 1.0% by mass or more, from the viewpoint of improving the time for which the bath additive produces carbon dioxide gas in the bathwater and improving the spread of bubbles on the surface of the bathwater. Also, the content is 5.5% by mass or less, preferably 5.0% by mass or less, more preferably 4.0% by mass or less, even more preferably 3.5% by mass or less, still more preferably 3.0% by mass or less, still more preferably 2.5% by mass or less, and still more preferably 2.2% by mass or less.

[0051] When the solid bath additive contains component (C1), the content of component (C1) in the solid bath additive is preferably 0.10% by mass or more, more preferably 0.20% by mass or more, even more preferably 0.30% by mass or more, still more preferably 0.50% by mass or more, still more preferably 0.75% by mass or more, still more preferably 0.90% by mass or more, and still more preferably 1.0% by mass or more, from the viewpoint of improving the time for which the bath additive produces carbon dioxide gas in the bath water and improving the spread of bubbles on the water surface. Also, the content of component (C1) is 5.5% by mass or less, preferably 5.0% by mass or less, more preferably 4.0% by mass or less, even more preferably 3.5% by mass or less, still more preferably 3.0% by mass or less, still more preferably 2.5% by mass or less, and still more preferably 2.2% by mass or less.

[0052] When the solid bath additive contains component (C2), the content of component (C2) in the solid bath additive is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, even more preferably 0.05% by mass or more, from the viewpoints of improving the time that the bath additive produces carbon dioxide gas bubbles in the water, improving the spread of bubbles on the water surface, and improving the release of fragrance while bathing, and is also 5.5% by mass or less, preferably 5.0% by mass or less, more preferably 3.0% by mass or less, even more preferably 2.0% by mass or less, still more preferably 1.0% by mass or less, still more preferably 0.50% by mass or less, still more preferably 0.20% by mass or less, and still more preferably 0.10% by mass or less.

[0053] The mass ratio of component (C) to component (A) in the solid bath additive [(C) / (A)] is preferably 0.20 or less, more preferably 0.15 or less, even more preferably less than 0.10, even more preferably 0.08 or less, and even more preferably 0.06 or less, from the viewpoint of improving the time that the bath additive produces carbon dioxide gas in the bath and improving the spread of bubbles on the surface of the water. Also, it is preferably 0.01 or more, more preferably 0.02 or more.

[0054] The mass ratio of component (C) to component (B) in the solid bath additive [(C) / (B)] is preferably 0.20 or less, more preferably 0.15 or less, even more preferably less than 0.10, even more preferably 0.08 or less, even more preferably 0.06 or less, and even more preferably 0.05 or less, from the viewpoint of improving the time that the bath additive produces carbon dioxide gas in the bath and improving the spread of bubbles on the surface of the water. Also, it is preferably 0.01 or more, more preferably 0.02 or more.

[0055] <Dosage form> The dosage form (product form) of the solid bath additive of the present invention is preferably a tablet. Tablets include compressed tablets and briquettes, and from the viewpoint of moldability of the solid bath additive, compressed tablets are more preferable. The solid bath additive of the present invention can be produced by a conventional method such as compression molding using a press tableting machine or a briquetting machine. In the manufacture of tableting or briquetting agents, for example, all of the components constituting the bath additive of the present invention may be dry-blended to obtain a powder, which may then be subjected to compression molding, or a portion of the components may be granulated or molded in advance, and then mixed with the remaining components to obtain a mixture, which may then be subjected to compression molding.

[0056] The mass of one tablet of the solid bath additive is preferably 20 g or more and 100 g or less, more preferably 35 g or more and 90 g or less, from the viewpoint of improving the time for which carbon dioxide gas bubbles in the water and improving the spread of bubbles on the surface of the water. [Example]

[0057] The present invention will be described below with reference to examples, but the present invention is not limited to the scope of the examples.

[0058] Examples 1 to 16 and Comparative Examples 1 to 7 (Preparation and Evaluation of Solid Bath Additives) The powder obtained by mixing the ingredients shown in the table below was compressed in a rotary tablet press at a speed of 20 tablets / min to produce tablet-shaped solid bath additives with a mass of 69-71 g and a tablet height of 19.3-19.5 mm. The resulting solid bath additives were evaluated using the methods described below. The blending amount (mass %) of each component shown in the table is the active amount. In the table, nonionic surfactants other than component (C) are referred to as "component (C')."

[0059] <Length of foaming time in hot water> One tablet of each solid bath additive was placed in a bathtub filled with 150 L of hot water at 40°C and allowed to dissolve while standing. Panelists visually evaluated the time until foaming in the water stopped (foaming time in the water) and rated it on a 5-point scale according to the following criteria. A score of 2 or higher was considered a pass, with higher scores indicating better results. Note that the "foaming time in the water" refers to the foaming time of the solid bath additive in the water, and does not include the foaming time after it floats to the surface during dissolution. 5: (Foaming time of the solid bath additive in hot water) - (Foaming time of the solid bath additive in Comparative Example 1 in hot water) is 2 minutes 30 seconds or more and less than 10 minutes. 4: (Foaming time of the solid bath additive in hot water) - (Foaming time of the solid bath additive in comparative example 1 in hot water) is 10 minutes or more and less than 15 minutes. 3: (Foaming time of the solid bath additive in hot water) - (Foaming time of the solid bath additive in Comparative Example 1 in hot water) is 1 minute or more and less than 2 minutes 30 seconds, or 15 minutes or more and less than 25 minutes. 2: (Bubble time of the solid bath additive in hot water) - (Bubble time of the solid bath additive in Comparative Example 1 in hot water) is 30 seconds or more and less than 1 minute, or 25 minutes or more. 1: (Bubble formation time of the solid bath additive in hot water) - (Bubble formation time of the solid bath additive in Comparative Example 1 in hot water) is less than 30 seconds.

[0060] <The spread of bubbles on the surface of the water> One tablet of each solid bath additive was placed in a bathtub filled with 150 L of hot water at 40°C and stirred by hand to dissolve the solid bath additive. Immediately after the solid bath additive had completely dissolved, a panelist visually evaluated the state of the water surface and rated it on a four-point scale according to the following criteria. A score of 2 or higher was considered a pass, with higher scores indicating better results. 4: Bubbles are visible on about 90% of the water surface. 3: Bubbles are seen to have spread over about 70% of the water surface. 2: Bubbles are seen to have spread over about 50% of the water surface. 1: The bubbles on the surface of the water have spread by approximately 30% or less, or the water is clear and free of bubbles.

[0061] <Fragrance> One tablet of the solid bath additive was placed in a bathtub filled with 150 L of hot water at 40°C and stirred by hand to dissolve the solid bath additive. Immediately after the solid bath additive had completely dissolved, a sensory evaluation was conducted on the fragrance release according to the following criteria, and the result was rated on a three-point scale. A higher score indicates better fragrance release. 3: Good fragrance 2: Scent is detectable (tolerable for practical use) 1: I can't smell the scent enough

[0062] [Table 1]

[0063] [Table 2]

[0064] [Table 3]

[0065] Details of the components listed in the table are as follows: <Component (C1)> Lauryl glucoside: Kao Corporation's "Mydol 12", HLB17 Polyoxyethylene lauryl ether: Kao Corporation's "Emulgen 123P", average EO moles: 23, HLB: 16.9 Sucrose palmitate: "Ryoto Sugar Ester P-1670" manufactured by Mitsubishi Chemical Corporation, HLB 16 Sucrose stearate: "Ryoto Sugar Ester S-1670" manufactured by Mitsubishi Chemical Corporation, HLB 16 <Component (C2)> Sucrose stearate: Mitsubishi Chemical Corporation's "Surfhope SE COSME C-1811", HLB11 Polyoxyethylene cetyl ether: Kao Corporation's "Emulgen 210P", average EO moles: 7, HLB: 10.7 Polyoxyethylene sorbitol tetraoleate: "Rheodol 440V" manufactured by Kao Corporation, average EO moles: 40, HLB: 10.5 <Component (C')> Sucrose stearate: Mitsubishi Chemical Corporation "Surfhope C-1807", HLB7 Glycerin fatty acid ester: "Sunsoft A-186C" manufactured by Taiyo Kagaku Co., Ltd., HLB4 Glyceryl stearate: Kao Corporation's "Rheodol MS-60", HLB 3.5 <Other> Polyethylene glycol 6000: Kao Corporation "K-PEG6000LA" Sodium N-lauroyl-L-glutamate: Ajinomoto Co., Inc. "Amisoft LS-11" N-Myristoyl-L-glutamic acid monosodium: Ajinomoto Co., Inc. "Amisoft MS-11"

[0066] The table shows that the solid bath additives of this example had a long time for carbon dioxide gas to bubble in the water and good spread of bubbles on the water surface. In contrast, the solid bath additives of Comparative Examples 1 to 7, which contained less than 0.10% by mass of component (C), were inferior in either the length of time for carbon dioxide gas to bubble in the water or the spread of bubbles on the water surface. [Industrial Applicability]

[0067] According to the present invention, a solid bath additive can be provided which can provide a higher relaxation effect because of the long time that carbon dioxide gas bubbles in the hot water, and further, can provide an enjoyable feeling of bubbles because the bubbles spread well on the surface of the hot water.

Claims

1. The following components (A), (B), and (C): (A) Carbonate (B) Organic acid (C) a nonionic surfactant with an HLB of 10 or more A solid bath additive containing The solid bath additive has a content of the component (C) of 0.10% by mass or more and 5.5% by mass or less.

2. 2. The solid bath additive according to claim 1, wherein the component (C) comprises a component (C1): a nonionic surfactant having an HLB of 14 or more.

3. 3. The solid bath additive according to claim 2, wherein the component (C) comprises a component (C1): a nonionic surfactant having an HLB of 14 or more, and a component (C2): a nonionic surfactant having an HLB of 10 or more and less than 14.

4. 4. The solid bath additive according to claim 3, wherein the mass ratio of component (C1) to component (C2) [(C1) / (C2)] is 3.0 or more and 90 or less.

5. The solid bath agent according to any one of claims 1 to 4, wherein the average HLB of all nonionic surfactants contained in the solid bath agent is 14 or more.

6. The solid bath additive according to any one of claims 1 to 4, wherein the component (C) comprises sucrose palmitate.

7. The solid bath additive according to any one of claims 1 to 4, wherein the mass ratio of component (C) to component (A) [(C) / (A)] is less than 0.

10.

8. The solid bath additive according to any one of claims 1 to 4, wherein the mass ratio of component (C) to component (B) [(C) / (B)] is less than 0.10.

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