Two-layer liquid bath additive

Abstract

To provide a two-layer liquid bath agent that includes a highly stable oil layer, has high emulsifiability in bath water during bathing, even if the bath water is at high temperature, and also has a high moisturizing effect after bathing.SOLUTION: A two-layer liquid bath agent contains component (A): a liquid oil agent, component (B): a nonionic surfactant, and component (C): glycerol, the component (B) containing a nonionic surfactant (B1) with an HLB of less than 11.0, a nonionic surfactant (B2) with an HLB of 11.0 or more and less than 13.0, and a nonionic surfactant (B3) with an HLB of 13.0 or more; the total content of the component (B1) and the component (B2) being 2 mass% or more and 11 mass% or less, the content of the component (B3) being 0.1 mass% or more and 3 mass% or less, and the mass ratio of the total content of the component (B2) and the component (B3) to the component (B1) [{(B2)+(B3)} / (B1)] being 0.1 or more and 1 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a two-layer liquid bath additive. [Background technology]

[0002] Two-layer liquid bath additives have been proposed that are mixed by shaking and stirring, and separate into an aqueous layer and an oil layer when left to stand (for example, Patent Documents 1 to 4). Before use, the appearance of a two-layered liquid bath additive can be enjoyed by, for example, coloring each layer a different color. Furthermore, when in use, the container filled with the liquid bath additive is shaken and stirred to mix the two layers, and then poured into bath water. If the liquid bath additive is a self-emulsifying type, the bath water becomes cloudy after pouring, allowing the user to enjoy the change in appearance. Furthermore, by incorporating skin care ingredients into the liquid bath additive, skin care effects can be obtained after bathing.

[0003] For example, Patent Document 1 discloses that a two-layer bath additive containing a predetermined amount of an oil agent, an emulsifier, a polyhydric alcohol, and ethanol that are liquid at room temperature has excellent moisturizing and emollient effects, excellent two-layer separation properties, excellent redispersibility from the two layers, and excellent opacity in bathwater, and exhibits a beautiful, transparent two-layer appearance. Patent Document 2 discloses that a bath additive has at least two layers in a static equilibrium state: a layer (first layer) whose main component is oil, and a layer (second layer) whose main component is polyhydric alcohol, and the difference in specific gravity between the first layer and the second layer is within a predetermined range, and that the bath additive favorably stimulates the sense of smell and touch and is useful for maintaining a healthy mind and body. Patent Document 3 discloses that cosmetics containing polyoxyethylene fatty acid glyceryl and diglycerin, which are suitable for use in scented bath additives, stimulate the senses of smell and touch in a favorable manner and are useful for maintaining a healthy mind and body. Patent Document 4 discloses that a two-layer liquid bath additive containing an oil, an emulsifier, and glycerin, containing water, and containing no separating agent, has excellent two-layer separation and redispersibility from the two layers, and has good opacity and an emulsified state when added to bathwater. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-182420 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-151665 [Patent Document 3] Japanese Patent Application Laid-Open No. 2001-328933 [Patent Document 4] Japanese Patent Application Laid-Open No. 2002-322046 Summary of the Invention [Problem to be solved by the invention]

[0005] Before use, two-layer liquid bath additives are expected to separate into two clear layers, an oil layer and an aqueous layer, and to have a good appearance. When used, they are stirred and mixed and poured into bath water, where they self-emulsify, making the bath water cloudy. It is desirable for self-emulsifying liquid bath additives to be able to maintain their cloudy state even when the bath water is reheated. The temperature of bath water during bathing is generally around 40°C. However, when the bath water is reheated, the temperature rises, and conventional bath additives are unable to maintain their self-emulsifying properties, which is a problem. Therefore, it is desirable for the bath additives to be able to stably express their emulsifying properties even in bath water at high temperatures of 50°C or above, preferably around 55°C. It is known that nonionic surfactants are used in two-layer liquid bath additives to maintain a good two-layer appearance before use and to improve the cloudiness of the bath water during use. However, when a nonionic surfactant with a polyether chain is used, the emulsifying ability in high-temperature bath water (hereinafter also referred to as "high-temperature emulsifying ability") tends to decrease. Furthermore, while it is possible to impart skin care effects by incorporating an oil as an oil layer component in a two-layer liquid bath additive, it was found that the stability of the oil layer decreases before use and that the moisturizing effect decreases after bathing, leaving room for improvement in order to satisfy all of the requirements for high-temperature emulsification, oil layer stability, and moisturizing effect. In the present invention, the stability of the oil layer means that the oil layer does not become cloudy or undergo layer separation. In the present invention, the temperature of the bath water during bathing is around 40°C.

[0006] The present invention relates to a two-layer liquid bath additive having a highly stable oil layer, high emulsifying properties in bath water during bathing (hereinafter also referred to as "bath water emulsifying properties") and in high-temperature bath water (high-temperature emulsifying properties), and an excellent moisturizing effect after bathing. [Means for solving the problem]

[0007] The inventors have discovered that the above problem can be solved by using nonionic surfactants with different HLB values ​​in a specified ratio in a two-layer liquid bath additive containing a liquid oil, a nonionic surfactant, and glycerin. That is, the present invention provides: Component (A): Liquid oil, Component (B): a nonionic surfactant, and Ingredient (C): Glycerin, Contains Component (B) contains a nonionic surfactant (B1) having an HLB of less than 11.0, a nonionic surfactant (B2) having an HLB of 11.0 or more and less than 13.0, and a nonionic surfactant (B3) having an HLB of 13.0 or more, the total content of component (B1) and component (B2) is 2% by mass or more and 11% by mass or less, The content of component (B3) is 0.1% by mass or more and 3% by mass or less, The present invention relates to a two-layer liquid bath additive in which the mass ratio of the total content of components (B2) and (B3) to component (B1) [{(B2) + (B3)} / (B1)] is 0.1 or more and 1 or less. [Effects of the Invention]

[0008] According to the present invention, a two-layer liquid bath additive can be provided which has a highly stable oil layer, high emulsification properties in bath water during bathing and in high-temperature bath water, and also has an excellent moisturizing effect after bathing. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Two-layer liquid bath additive] The two-layer liquid bath additive of the present invention (hereinafter also referred to simply as "the bath additive of the present invention") is Component (A): Liquid oil, Component (B): a nonionic surfactant, and Ingredient (C): Glycerin, Contains Component (B) contains a nonionic surfactant (B1) having an HLB of less than 11.0, a nonionic surfactant (B2) having an HLB of 11.0 or more and less than 13.0, and a nonionic surfactant (B3) having an HLB of 13.0 or more, the total content of component (B1) and component (B2) is 2% by mass or more and 11% by mass or less, The content of component (B3) is 0.1% by mass or more and 3% by mass or less, The mass ratio of the total content of components (B2) and (B3) to component (B1) [{(B2)+(B3)} / (B1)] is 0.1 or more and 1 or less. By using the above-described composition of the bath additive of the present invention, it is possible to produce a two-layer liquid bath additive that has a highly stable oil layer, high bath water emulsification properties and high-temperature emulsification properties, and also has an excellent moisturizing effect after bathing.

[0010] In the bath additive of the present invention, components (A) and (B) constitute the oil layer of the two-layer liquid bath additive, and component (C) constitutes the aqueous layer. By using a predetermined amount of a highly hydrophilic nonionic surfactant (B3) with an HLB of 13.0 or higher as component (B), it is believed that the self-emulsifying properties in bath water during bathing are improved, and therefore the high-temperature emulsifying properties are also improved. In this invention, we use nonionic surfactants (components (B1) and (B2)) with a high affinity for component (A) and an HLB value of less than 13.0, and a highly hydrophilic nonionic surfactant (B3) with an HLB value of 13.0 or greater, and by setting the content and mass ratio of these in the two-layer liquid bath additive within a specified range, we believe that we can improve the stability of the oil layer while maintaining the moisturizing effect of component (A). Furthermore, by using components (B1) and (B2) in combination as nonionic surfactants with an HLB value of less than 13.0, we can further improve the stability of the oil layer, maintain a stable two-layer state with a good appearance, and prevent a decrease in moisturizing effect after bathing.

[0011] <Component (A): Liquid oil> The bath additive of the present invention contains a liquid oil as component (A). In the present invention, "liquid" means that the liquid is in a liquid state at 25°C. Component (A) is not particularly limited as long as it is a liquid oil used in ordinary bath additives, and examples thereof include hydrocarbon oils, silicone oils, ester oils, higher fatty acids, higher alcohols, fluorine-based oils, etc., which are liquid at 25° C. These may be naturally derived oils such as vegetable oils and animal oils.

[0012] Examples of hydrocarbon oils include linear or branched hydrocarbon oils that are liquid at 25° C., such as liquid paraffin, light liquid isoparaffin, squalane, and squalene. Among these, liquid paraffin is preferred from the viewpoints of improving the stability of the oil layer and improving the moisturizing effect after bathing.

[0013] Examples of silicone oils include dimethylpolysiloxane, dimethylcyclopolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, and higher alcohol-modified silicone oils that are liquid at 25° C. Among these, dimethylpolysiloxane is preferred from the viewpoints of improving the stability of the oil layer and improving the moisturizing effect after bathing. The viscosity of the silicone oil is preferably 1 mm kinematic viscosity at 25°C in order to prevent excessive evaporation. 2 / s or more, preferably 2 mm 2 / s or more, more preferably 5 mm 2 / s or more, and from the viewpoint of facilitating stirring and mixing, it is preferably 5,000 mm 2 / s or less, preferably 3,000 mm 2 / s or less, and more preferably 1,000 mm 2 / s or less, and even more preferably 400 mm 2 / s or less, and even more preferably 100 mm 2 The kinematic viscosity can be measured using, for example, an Ubbelohde viscometer.

[0014] Examples of ester oils include fatty acid esters composed of fatty acids and monohydric or dihydric alcohols, glycerin fatty acid esters (glycerides) composed of fatty acids and glycerin, etc. The number of carbon atoms in the fatty acid is preferably 8 to 24, more preferably 8 to 20, and even more preferably 8 to 18, from the viewpoint of improving the stability of the oil layer and the moisturizing effect after bathing. Specific examples of ester oils used as component (A) include cetyl octanoate, cetyl isooctanoate, myristyl lactate, cetyl lactate, isopropyl myristate, myristyl myristate, isocetyl myristate, octyldodecyl myristate, isopropyl palmitate, isostearyl palmitate, isopropyl adipate, butyl stearate, isocetyl stearate, isotridecyl isononanoate, decyl oleate, cholesterol isostearate, butyl laurate, isoamyl laurate, and myristate. Fatty acid esters such as methyl, ethyl myristate, ethyl stearate, isononyl isononanoate, isopropyl linoleate, isostearyl isostearate, isopropyl isostearate, methyl oleate, ethyl oleate, oleyl oleate, and ethyl 2-ethylhexanoate; glycerin fatty acid esters (glycerides) such as caprylic / capric triglyceride (INCI name "caprylic / capric triglyceride"), myristate triglyceride, and 2-ethylhexanoate triglyceride; etc.

[0015] Higher fatty acids include fatty acids having 8 to 24 carbon atoms, such as oleic acid, linoleic acid, linolenic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, lanolinic acid, and isostearic acid. Examples of higher alcohols include alcohols having 8 to 24 carbon atoms, more preferably 8 to 18 carbon atoms, and specific examples include lauryl alcohol, oleyl alcohol, cetyl alcohol, stearyl alcohol, isostearyl alcohol, 2-hexyldecanol, 2-octyldodecanol, and cholesterol.

[0016] Examples of fluorine-based oils include fluoropolyethers and perfluoroalkyl ether silicones that are liquid at 25°C.

[0017] Examples of vegetable oils include soybean oil, rice germ oil, rice bran oil, jojoba oil, avocado oil, almond oil, olive oil, cacao butter, sesame oil, persic oil, castor oil, coconut oil, safflower oil, eucalyptus oil, rapeseed oil, and oils obtained by hydrogenating these oils that are liquid at 25°C. Examples of animal oils include mink oil and liquid lanolin.

[0018] One or more types of component (A) can be used. Among the above, from the viewpoint of improving the oil layer stability, improving the moisturizing effect after bathing, and improving the emulsification properties of the bath water, component (A) is preferably one or more oils selected from the group consisting of hydrocarbon oils, silicone oils, and ester oils, and more preferably contains at least one oil or more selected from the group consisting of hydrocarbon oils and silicone oils. From the viewpoints of improving the oil layer stability, improving the moisturizing effect after bathing, and improving the emulsifying properties of the bath water, it is more preferable that component (A) contains a hydrocarbon oil, a silicone oil, and an ester oil, and it is even more preferable that it contains liquid paraffin, dimethylpolysiloxane, isopropyl myristate, and tri(caprylic / capric acid)glyceryl. The total content of hydrocarbon oil, silicone oil, and ester oil in component (A) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more, and may be 100% by mass, from the viewpoint of improving the oil layer stability, improving the moisturizing effect after bathing, and improving the emulsification properties of bath water. When component (A) contains silicone oil, the content of silicone oil in the two-layer liquid bath additive is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, from the viewpoints of improving the stability of the oil layer, improving the moisturizing effect after bathing, and improving the emulsification of bath water, and is preferably 5% by mass or less, more preferably 4% by mass or less, even more preferably 3% by mass or less.

[0019] The content of component (A) in the two-layer liquid bath additive is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, from the viewpoints of improving the moisturizing effect after bathing and improving the emulsification of bath water. Also, from the viewpoints of ensuring the amount of aqueous layer and forming an attractive two-layer appearance, the content is preferably 65% ​​by mass or less, more preferably 60% by mass or less, even more preferably 55% by mass or less, even more preferably 50% by mass or less, and even more preferably 40% by mass or less.

[0020] <Component (B): Nonionic surfactant> The bath additive of the present invention contains a nonionic surfactant as component (B). Component (B) contains a nonionic surfactant (B1) with an HLB of less than 11.0, a nonionic surfactant (B2) with an HLB of 11.0 or more but less than 13.0, and a nonionic surfactant (B3) with an HLB of 13.0 or more. HLB (Hydrophilic-Lipophilic Balance) indicates the ratio of the molecular weight of the hydrophilic group portion to the total molecular weight of the surfactant, and is calculated using the following Griffin equation. HLB = 20 × [(molecular weight of hydrophilic group contained in surfactant) / (molecular weight of surfactant)]

[0021] (Component (B1)) Component (B1) is a nonionic surfactant with an HLB of less than 11.0. From the viewpoint of improving oil layer stability, bath water emulsification properties, and high-temperature emulsification properties, the HLB of component (B1) is preferably 10.5 or less, more preferably 10 or less, and is also preferably 4 or more. When component (B1) contains two or more nonionic surfactants, all of the nonionic surfactants used have an HLB within the above range.

[0022] From the viewpoints of improving oil layer stability, bath water emulsification, and high-temperature emulsification, component (B1) more preferably contains a nonionic surfactant (B1') having an HLB of 5 or less. The HLB of component (B1') is preferably 4.5 or less and 4 or more. When component (B1) contains component (B1'), the content of component (B1') in component (B1) is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 4% by mass or more, from the viewpoint of improving oil layer stability, bath water emulsification, and high-temperature emulsification; and from the viewpoint of improving the moisturizing effect after bathing, it is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 15% by mass or less. When component (B1') contains two or more nonionic surfactants, all of the nonionic surfactants used have an HLB within the above range.

[0023] (Component (B2)) Component (B2) is a nonionic surfactant having an HLB of 11.0 or greater and less than 13.0. The HLB of component (B2) is preferably 11.5 or more, more preferably 12.0 or more, and preferably 12.5 or less, from the viewpoint of improving oil layer stability, improving bath water emulsification properties, and improving high-temperature emulsification properties. When component (B2) contains two or more nonionic surfactants, all of the nonionic surfactants used have an HLB within the above range.

[0024] (Component (B3)) Component (B3) is a nonionic surfactant having an HLB of 13.0 or more. From the viewpoint of improving high-temperature emulsifiability, the HLB of component (B3) is preferably 13.5 or more, more preferably 14 or more. From the viewpoint of improving oil layer stability, the HLB is preferably 20 or less, more preferably 18 or less, and even more preferably 16 or less. When component (B3) contains two or more nonionic surfactants, all of the nonionic surfactants used have an HLB within the above range.

[0025] Specific examples of component (B) 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.

[0026] 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, polyoxyethylene sorbitan fatty acid esters, and polyoxyethylene fatty acid esters preferably have from 8 to 22 carbon atoms, more preferably from 10 to 22 carbon atoms, even more preferably from 12 to 20 carbon atoms, and still more preferably from 14 to 20 carbon atoms, from the viewpoint of improving oil layer stability, bath water emulsification ability, and high-temperature emulsification ability.

[0027] Among the above, from the viewpoint of improving the oil layer stability and the bath water emulsification properties, it is preferable that component (B) contains a nonionic surfactant having a polyether chain. When a nonionic surfactant having a polyether chain is used as component (B), there is a tendency for high-temperature emulsification properties to decrease. However, in the bath additive of the present invention, by using components (B1) to (B3) in the respective predetermined proportions, it is possible to improve high-temperature emulsification properties even when a nonionic surfactant having a polyether chain is used. The nonionic surfactant having a polyether chain may be contained in at least one of components (B1) to (B3), and from the viewpoint of improving the oil layer stability and the bath water emulsification properties, it is preferable that it be contained in all of components (B1) to (B3).

[0028] Examples of nonionic surfactants having a polyether chain include one or more selected from the group consisting of 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. The average number of moles of ethylene oxide added (hereinafter referred to as the "average number of moles of EO added") in the 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 preferably 2 or more, more preferably 3 or more, and even more preferably 5 or more, from the viewpoints of improving oil layer stability, bath water emulsification, and high-temperature emulsification, and is preferably 150 or less, more preferably 80 or less, even more preferably 60 or less, and even more preferably 50 or less. The average number of moles of EO added is a number average value.

[0029] Among the above, the nonionic surfactant having a polyether chain is preferably one or more selected from the group consisting of polyoxyethylene alkyl ethers, polyoxyethylene alkenyl ethers, polyoxyethylene sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters, more preferably one or more selected from the group consisting of polyoxyethylene sorbitan fatty acid esters and polyoxyethylene sorbitan fatty acid esters, and even more preferably polyoxyethylene sorbitan fatty acid esters and polyoxyethylene sorbitan fatty acid esters. The carbon number of these alkyl groups, alkenyl groups, or fatty acids is preferably 8 to 22, more preferably 10 to 22, even more preferably 12 to 20, and still more preferably 14 to 20.

[0030] Specific examples of polyoxyethylene alkyl ethers include polyoxyethylene lauryl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, and polyoxyethylene behenyl ether. Specific examples of polyoxyethylene alkenyl ethers include polyoxyethylene oleyl ether. Specific examples of polyoxyethylene sorbitan fatty acid esters include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monooleate, and polyoxyethylene coconut oil fatty acid sorbitan. 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, and polyoxyethylene sorbitol mono-, di-, tri-, or tetra-stearate.

[0031] A preferred combination of components (B1) to (B3) is a combination in which component (B1) comprises a polyoxyethylene sorbitan fatty acid ester, preferably polyoxyethylene sorbitan monooleate; component (B2) is one or more selected from the group consisting of polyoxyethylene sorbitan fatty acid esters and polyoxyethylene sorbitan fatty acid esters, preferably one or more selected from the group consisting of polyoxyethylene sorbitan monooleate and polyoxyethylene sorbit tetraoleate, more preferably polyoxyethylene sorbit tetraoleate; and component (B3) is one or more selected from the group consisting of polyoxyethylene sorbitan fatty acid esters and polyoxyethylene sorbitan fatty acid esters, preferably one or more selected from the group consisting of polyoxyethylene sorbitan monooleate and polyoxyethylene sorbit tetraoleate, more preferably polyoxyethylene sorbitan monooleate.

[0032] When component (B1) contains a nonionic surfactant (B1') with an HLB of 5 or less, component (B1') is preferably a sorbitan fatty acid ester. Specific examples of sorbitan fatty acid esters include sorbitan monolaurate and sorbitan monooleate, with sorbitan monooleate being preferred.

[0033] The total content of component (B1) and component (B2) in the two-layer liquid bath additive is 2% by mass or more, preferably 3% by mass or more, more preferably 4% by mass or more, and even more preferably 5% by mass or more, from the viewpoints of improving the oil layer stability, bath water emulsification, and high-temperature emulsification. Furthermore, from the viewpoint of improving the moisturizing effect after bathing, the total content is 11% by mass or less, preferably 9% by mass or less, more preferably 7% by mass or less, and even more preferably 6% by mass or less.

[0034] The content of component (B3) in the two-layer liquid bath additive is 0.1% by mass or more, preferably 0.2% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, from the viewpoint of improving high-temperature emulsification properties. Also, from the viewpoint of improving oil layer stability, the content is 3% by mass or less, preferably 1.5% by mass or less, and more preferably 1% by mass or less.

[0035] The mass ratio of the total content of components (B2) and (B3) to component (B1) in the two-layer liquid bath additive [{(B2) + (B3)} / (B1)] is, from the viewpoint of improving the oil layer stability and improving high-temperature emulsification properties, 0.1 or more, preferably 0.2 or more, more preferably 0.3 or more, even more preferably 0.4 or more, still more preferably 0.5 or more, still more preferably 0.55 or more, and is 1 or less, preferably 0.9 or less, more preferably 0.8 or less, even more preferably 0.75 or less.

[0036] Furthermore, the content of component (B) in the two-layer liquid bath additive is preferably 2.2% by mass or more, more preferably 2.5% by mass or more, even more preferably 4% by mass or more, and even more preferably 5% by mass or more, from the viewpoint of improving the oil layer stability, the bath water emulsification ability, and the high-temperature emulsification ability, and is preferably 12% by mass or less, more preferably 10% by mass or less, even more preferably 8% by mass or less, and even more preferably less than 7% by mass, from the viewpoint of improving the moisturizing effect after bathing.

[0037] In the present invention, the HLB of component (B) as a whole is preferably 6 or more, more preferably 8 or more, even more preferably 10 or more, from the viewpoint of improving oil layer stability, bath water emulsification ability, and high-temperature emulsification ability, and is preferably 16 or less, more preferably 14 or less, even more preferably 12 or less. In the present invention, the HLB of the entire component (B) refers to the HLB of the mixture of nonionic surfactants (hereinafter also referred to as "mixed HLB"). Here, the mixed HLB is a weighted average of the HLBs of the individual nonionic surfactants based on their mass ratios, and is calculated by the following formula: Mixed HLB=Σ(HLBx×Wx) / ΣWx (HLBx represents the HLB of nonionic surfactant X. Wx represents the mass (g) of nonionic surfactant X.)

[0038] <Component (C): Glycerin> The bath additive of the present invention contains glycerin as component (C), which forms the lower aqueous layer of the two-layer liquid bath additive. The content of component (C) in the two-layer liquid bath additive is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more, from the viewpoints of ensuring the amount of aqueous layer, forming a beautiful two-layer appearance, and improving the moisturizing effect during bathing. Also, from the viewpoint of improving the emulsification properties of bath water, the content is preferably 65% ​​by mass or less, more preferably 60% by mass or less, even more preferably 55% by mass or less, and even more preferably 50% by mass or less.

[0039] <Water> The bath additive of the present invention preferably further contains water, from the viewpoint of facilitating mixing by shaking and stirring. The water content in the two-layer liquid bath additive is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 3% by mass or more, and even more preferably 5% by mass or more, from the viewpoint of facilitating mixing by shaking and stirring. Also, from the viewpoint of improving the emulsifying properties of bath water and improving the moisturizing effect during bathing, the water content is preferably 15% by mass or less, more preferably 12% by mass or less, and even more preferably 10% by mass or less.

[0040] <Other ingredients> The bath additives of the present invention may include other ingredients, such as surfactants other than component (B); water-soluble polymers such as polyethylene glycol and dextrin; opacifiers such as titanium oxide; preservatives such as sodium benzoate; medicinal ingredients such as herbal medicines; pigments such as Blue No. 1, Blue No. 2, Yellow No. 4, Yellow No. 5, Green No. 3, Green No. 4, Green No. 204, Yellow No. 202, Yellow No. 203, Red No. 106, chlorophyll, riboflavin, crocin, anthraquinone, cochineal, canthaxanthin, and safflower; fragrances; etc. Among the above, the bath additive of the present invention preferably contains a preservative, a coloring matter, and a fragrance. In addition, as for a component having multiple uses, for example, menthol may be used not only as a cooling agent but also as a fragrance.

[0041] The bath additive of the present invention preferably contains less than 0.1% by mass, more preferably less than 0.01% by mass, and may even contain substantially 0% by mass of ethanol, from the viewpoints of improving the emulsifying properties of bath water, improving the emulsifying properties at high temperatures, and improving the moisturizing effect during bathing.

[0042] From the viewpoint of obtaining the effects of the present invention, the total content of components (A) to (C) in the two-layer liquid bath additive is preferably 50% by mass or more, more preferably 65% ​​by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 85% by mass or more, and may be 100% by mass.

[0043] <Dosage form, manufacturing method, etc.> The bath additive of the present invention is a two-layer liquid bath additive, and is filled, for example, in a sealable transparent container. There are no particular limitations on the method for producing the bath additive of the present invention, and it can be prepared by blending and mixing the above-mentioned components. There are no particular restrictions on the order in which the components in a two-layer liquid bath additive are mixed, but from the standpoint of manufacturing efficiency, it is preferable to first mix component (A), component (B), and fragrance, etc., which make up the oil layer, and fill the container, and then mix component (C), which makes up the aqueous layer, and water, preservatives, colorants, etc., which are used as needed, and fill the container.

[0044] The bath additive of the present invention provides good cloudiness in bath water even when used in small amounts. The amount of the bath additive of the present invention used is preferably 5 mL to 45 mL, more preferably 10 mL to 45 mL, and even more preferably 15 mL to 30 mL per 150 L of bath water.

[0045] The bath additive of the present invention is mixed by shaking the container before use, and then added to bath water. The bath additive of the present invention is a self-emulsifying type, and after being added to bath water, it quickly disperses in the bath water, making the bath water cloudy. Furthermore, the bath additive of the present invention has good emulsifying properties in bath water at 50°C or higher, and the bath water remains highly cloudy even when reheated. [Example]

[0046] The present invention will be described below with reference to examples, but the present invention is not limited to the scope of the examples.

[0047] Examples 1 to 14 and Comparative Examples 1 to 6 (Preparation and Evaluation of Two-Layer Liquid Bath Additives) Of the ingredients shown in Tables 1 to 3, the ingredients (A) and (B) constituting the oil layer and the fragrance were mixed and filled into a 30 mL transparent container. Next, ingredient (C), water, sodium benzoate, and a water-soluble colorant were mixed and filled into the container to prepare a liquid bath additive. Additionally, bath water emulsification ability, high-temperature emulsification ability, moisturizing effect after bathing, and oil layer stability were evaluated using the methods described below. The results are shown in Tables 1 to 3. The content (mass%) of each component shown in Tables 1 to 3 is the active amount.

[0048] <Bath water emulsifying property> A sealed container filled with 18 mL of each two-layered liquid bath additive was shaken to mix, and then the contents were poured into 150 L of bath water at 40°C. Immediately after stirring, the bath water was visually observed and its emulsification ability was evaluated according to the following criteria. The higher the value, the greater the degree of cloudiness of the bath water. 4: No oil floating is observed and the bath water is sufficiently cloudy 3: No oil floating is observed, and the bath water becomes cloudy 2: Oil is visible, but the bath water is cloudy 1: Oil floating is observed and the bath water is not very cloudy.

[0049] <High temperature emulsifying property> After shaking and mixing the sealed container of each two-layer liquid bath additive, 0.1 g of the resulting preparation was poured into 500 mL of hot water at 55°C. The water was stirred and allowed to stand for 10 minutes, after which it was visually observed and evaluated for high-temperature emulsification according to the following criteria. The higher the value, the greater the degree of cloudiness of the bath water. 4: No oil is visible and the water is cloudy 3: No oil is visible and the water is cloudy 2: Oil is visible, but the water is cloudy 1: Oil is visible and the water is not very cloudy

[0050] <Moisturizing effect after bathing> A sealed container filled with 18 mL of each two-layered liquid bath additive was shaken to mix, and then the contents were poured into 150 L of bath water at 40°C. Immediately after stirring the bath water, three expert panelists bathed for 10 minutes. After towel drying, the skin's moisturizing sensation 10 minutes after bathing was evaluated according to the following criteria. The average scores of the three panelists are shown in Table 1. The higher the number, the greater the moisturizing effect. 4: I feel a strong moisturizing effect 3: I feel the moisturizing effect 2: I feel a slight moisturizing effect 1: No moisturizing effect

[0051] <Oil layer stability> The oil layer of a two-layer liquid bath additive was prepared by adding component (A), component (B), and a fragrance from the compositions in Tables 1 to 3. The solution was filled into a 30 mL transparent container, sealed with a lid, and stored at 40°C for 3 days. After storage, the appearance was visually observed, and the oil layer stability was evaluated according to the following criteria. A higher value indicates better oil layer stability. 3: Transparent uniform 2: Slight cloudiness occurs 1: Turbidity or layer separation occurs

[0052] [Table 1]

[0053] [Table 2]

[0054] [Table 3]

[0055] *1 Liquid paraffin: Kaneda Co., Ltd. "Hicol K-230" *2 Isopropyl myristate: Kao Corporation's "Excepearl IPM" *3 Caprylic / capric triglyceride: Kao Corporation's "Coconard MT" *4 Methylpolysiloxane: Shin-Etsu Chemical Co., Ltd. "KF-96A-10CS" *5 Sorbitan monooleate: "Rheodol AO-10V" manufactured by Kao Corporation *6 Polyoxyethylene (6) sorbitan monooleate: Kao Corporation's "Rheodor TW-O106V" *7 Polyoxyethylene (40) sorbitol tetraoleate: Nikkol GO-440V manufactured by Nikko Chemicals Co., Ltd. *8 Polyoxyethylene (20) sorbitan monooleate: Kao Corporation's "Rheodor TW-O120V" [Industrial Applicability]

[0056] According to the present invention, a two-layer liquid bath additive can be provided which has a highly stable oil layer, high emulsification properties in bath water during bathing and in high-temperature bath water, and also has an excellent moisturizing effect after bathing.

Claims

1. Component (A): A liquid oil containing caprylic / capric triglyceride. Component (B): a nonionic surfactant, and Component (C): glycerin, Contains Component (B) contains a nonionic surfactant (B1) having an HLB of less than 11.0, including a nonionic surfactant (B1') having an HLB of 5 or less, a nonionic surfactant (B2) having an HLB of 11.0 or more but less than 13.0, and a nonionic surfactant (B3) having an HLB of 13.0 or more, The content of component (B1') in component (B) is 2% by mass or more and 40% by mass or less, the total content of component (B1) and component (B2) is 3% by mass or more and 11% by mass or less, The content of component (B3) is 0.1% by mass or more and 1.5% by mass or less, A two-layer liquid bath additive, in which the mass ratio of the total content of components (B2) and (B3) to component (B1), [{(B2) + (B3)} / (B1)], is 0.1 or more and 0.8 or less.

2. 2. The two-layer liquid bath additive according to claim 1, wherein component (A) is at least one selected from the group consisting of hydrocarbon oils, silicone oils, and ester oils.

3. 3. The two-layer liquid bath additive according to claim 1, wherein the total content of components (A) to (C) is 80% by mass or more.

4. 4. The two-layer liquid bath additive according to claim 1, wherein component (B) comprises a nonionic surfactant having a polyether chain.

5. The two-layer liquid bath additive according to any one of claims 1 to 4, wherein the ethanol content is less than 0.1% by mass.

Images