Water-in-oil composition

Abstract

Provided is an oil-in-water type composition containing: (A) an organic modified clay mineral; (B) at least 3 mass% of a polar oil having an IOB of 0.3 or more; (C) a non-polar oil having an alkyl side chain; (D1) a polyoxyethylene-hardened castor oil; and (D2) an emulsion activator, which is a compound that has an alkyl side chain having 10 or more carbon atoms, a compound that has a fatty acid side chain having 10 or more carbon atoms, or a polyoxyethylene adduct thereof.

Description

[Technical Field]

[0001] The present invention relates to water-in-oil compositions. [Background technology]

[0002] Water-in-oil compositions, which have an oil-based component as the external phase and an aqueous component as the internal phase, are excellent in moisturizing properties, occlusive properties, etc. when applied to the skin, and are therefore widely used as cosmetics, quasi-drugs, etc. In order for water-in-oil compositions to properly perform their functions, it is important that the emulsion state between the oil-based component and the aqueous component is stable, and various ideas for stabilization have been investigated.

[0003] For example, it is known to use an organically modified clay mineral as an emulsifying aid, as described in Patent Document 1. The organically modified clay mineral can be used in appropriate combination with a surfactant to form a stable gel composition. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-107865 Summary of the Invention [Problem to be solved by the invention]

[0005] Water-in-oil compositions are often used as skin linings (cosmetics, personal care products, etc.) with UV protection properties. In these cases, polar oils with high UV absorption properties are included. However, increasing the polar oil content makes it difficult to stably maintain the emulsion state between the oil-based and water-based components and the gel-like properties of the organically modified clay mineral.

[0006] In view of the above, an object of one aspect of the present invention is to improve the stability of the properties of a water-in-oil composition containing a polar oil. [Means for solving the problem]

[0007] One aspect of the present invention for solving the above problems is a water-in-oil composition containing (A) an organically modified clay mineral, (B) 3 mass% or more of a polar oil having an IOB of 0.3 or more, (C) a non-polar oil having an alkyl side chain, (D1) polyoxyethylene hydrogenated castor oil, and (D2) an emulsifying surfactant which is a compound having an alkyl side chain with 10 or more carbon atoms, or a compound having a fatty acid side chain with 10 or more carbon atoms, or a polyoxyethylene adduct thereof. [Effects of the Invention]

[0008] According to one aspect of the present invention, the stability of the properties of a water-in-oil composition containing a polar oil can be improved. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments.

[0010] <Water-in-oil composition> The water-in-oil composition according to the first embodiment of the present invention contains (A) an organically modified clay mineral, (B) 3 mass % or more of a polar oil having an IOB of 0.3 or more, (C) a non-polar oil having an alkyl side chain, (D1) polyoxyethylene hydrogenated castor oil, and (D2) an emulsifying surfactant which is a compound having an alkyl side chain with 10 or more carbon atoms, or a compound having a fatty acid side chain with 10 or more carbon atoms, or a polyoxyethylene adduct thereof.

[0011] Furthermore, the water-in-oil composition according to the second embodiment of the present invention contains (A) an organically modified clay mineral, (B) 3 mass% or more of a polar oil having an IOB of 0.3 or more, (C) a non-polar oil having an alkyl side chain, and (D) a fatty acid ester of polyoxyethylene hydrogenated castor oil.

[0012] The water-in-oil composition according to the present invention may be solid or semi-solid, and may be provided in a form known as a gel, jelly, cream, balm, etc. Water-in-oil compositions in such a form are easy to apply as a skin liniment and can form a film of a certain thickness on the surface of the skin, thereby providing a strong effect of protecting and occluding the skin.

[0013] [First embodiment] <(A) Organically modified clay minerals> The (A) organically modified clay mineral is not particularly limited as long as it is one that is commonly used in skin application preparations. The (A) organically modified clay mineral may be, for example, a cationically modified clay mineral obtained by treating a layered clay mineral such as bentonite, laponite, hectorite, montmorillonite, or magnesium aluminum silicate with a quaternary ammonium salt-type cationic surfactant. Specific examples of the (A) organically modified clay mineral include dimethyl disteardimonium hectorite (disteardimonium hectorite), dimethyl alkyl ammonium hectorite, benzyl dimethyl stearyl ammonium hectorite, and magnesium aluminum silicate treated with distearyl dimethyl ammonium chloride. Commercially available products include Bentone 27 (benzyl dimethylstearyl ammonium chloride-treated hectorite; manufactured by National Red Co., Ltd. and Rheox Corporation), Bentone 34 (chemical name: quaternium-18 bentonite; manufactured by Rheox Corporation), Bentone 38 (distearyl dimethyl ammonium chloride-treated hectorite; manufactured by National Red Co., Ltd.), Bentone 38V (quaternium-18 hectorite; manufactured by Rheox Corporation), Claytone 40 (manufactured by Southern Clay Corporation), and Claytone SO (manufactured by Southern Clay Corporation). Among these, dimethyl distearyl ammonium hectorite and benzyl dimethyl stearyl ammonium hectorite are preferred, and dimethyl distearyl ammonium hectorite is even more preferred. These (A) organically modified clay minerals can be used alone or in combination of two or more.

[0014] The organically modified clay mineral (A) can function as an emulsifying aid that promotes emulsification of the oil-based component and the aqueous component. More specifically, the addition of the organically modified clay mineral (A) can effectively thicken or gel the oil-based component, and the gelled state of the oil phase can be maintained over time, which stabilizes the dispersed state of the aqueous phase and allows the entire water-in-oil composition to be stably maintained in a solid or semi-solid state or in a gelled state over a long period of time.

[0015] The content of the (A) organically modified clay mineral may be preferably 0.05% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 5% by mass or less, based on the total amount of the water-in-oil composition. A content of the (A) organically modified clay mineral of 0.05% by mass or more can impart sufficient stability to the water-in-oil composition, while a content of 10% by mass or less can provide a good feel in use with less stickiness and improve usability, such as lighter spread on the skin.

[0016] <(B) Polar oil> The (B) polar oil may be a relatively highly polar oily component commonly used in skin applications. The IOB value of the (B) polar oil used in this embodiment may be 0.3 or more. The IOB value of the (B) polar oil may be preferably 0.8 or less, more preferably 0.7 or less. When the (B) polar oil contains an ultraviolet absorber (described below), the IOB value of the ultraviolet absorber is preferably 0.3 or more and 0.7 or less. By having the (B) polar oil have an IOB value of 0.3 or more, the gel-like properties of the water-in-oil composition can be stabilized, and this stable state can be maintained over time.

[0017] The IOB value, an abbreviation for Inorganic / Organic Balance, represents the ratio of inorganic to organic values and serves as an index of the polarity of an organic compound. Specifically, the IOB value is expressed by the formula "IOB value = inorganic value / organic value." The "inorganic value" and "organic value" are determined according to the type of atom or functional group, e.g., an "organic value" of 20 for one carbon atom in a molecule and an "inorganic value" of 100 for one hydroxyl group in a molecule. The IOB value of an organic compound can be calculated by integrating the "inorganic value" and "organic value" of all atoms and functional groups in the compound (see, for example, Fujita, "Chemical Region," Vol. 11, No. 10, pp. 719-725, 1957). The higher the IOB value, the higher the inorganicity and hydrophilicity of the compound. When the (B) polar oil is a combination of two or more oils with different IOB values, the IOB value of the (B) polar oil shall be a weighted average value.

[0018] The content of (B) polar oil can be 3% by mass or more based on the total amount of the water-in-oil composition. Furthermore, depending on the function or use of the composition, the content of (B) polar oil can be preferably 5% by mass or more, more preferably 7% by mass or more, based on the total amount of the composition. By setting the lower limit of the content of (B) polar oil within the above range, moisturizing action, occlusion action, etc. can be enhanced. Furthermore, according to the composition of this embodiment, even when a relatively high content of (B) polar oil is contained, such as within the above range, the water-in-oil emulsified state of the composition can be stabilized.

[0019] The content of (B) polar oil may be preferably 30% by mass or less, more preferably 20% by mass or less, based on the total amount of the composition. By setting the upper limit of the content of (B) polar oil to the above value, the stability of the formulation can be improved, stickiness upon application can be suppressed, and a better feel can be obtained.

[0020] The polar oil (B) preferably contains an ultraviolet absorber, i.e., a polar oil having an ultraviolet absorbing function. When the polar oil (B) contains an ultraviolet absorber, the water-in-oil composition of this embodiment can be suitably used as a cosmetic composition having a sunscreen effect or a sunscreen composition.

[0021] The type of UV absorber contained in (B) polar oil is not particularly limited, and may be a benzoic acid derivative, a salicylic acid derivative, a cinnamic acid derivative, a dibenzoylmethane derivative, a β,β-diphenylacrylate derivative, a benzophenone derivative, a benzylidene camphor derivative, a phenylbenzimidazole derivative, a triazine derivative, a phenylbenzotriazole derivative, an anthranil derivative, an imidazoline derivative, a benzalmalonate derivative, a 4,4-diarylbutadiene derivative, etc. Specific examples include octyl salicylate (IOB=0.6), octocrylene (IOB=0.32), homosalate (IOB=0.6), ethylhexyl methoxycinnamate (IOB=0.35), etc., with octyl salicylate (IOB=0.6), octocrylene (IOB=0.32), and homosalate (IOB=0.6) being preferred. The ultraviolet absorbents may be used alone or in combination of two or more.

[0022] The content of the ultraviolet absorber relative to the total amount of (B) polar oil may be 100% by mass, that is, (B) polar oil in the water-in-oil composition of this embodiment may be the ultraviolet absorber.

[0023] The content of the ultraviolet absorber may be preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more, based on the total amount of the water-in-oil composition. The content of the ultraviolet absorbing polar oil may be preferably 20% by mass or less, based on the total amount of the water-in-oil composition. By keeping the content of the ultraviolet absorber within the above range, it is possible to provide a water-in-oil composition that has stable properties while maintaining ultraviolet protection function.

[0024] Specific examples of ester oils include diisopropyl sebacate (IOB=0.4), glyceryl tri-2-ethylhexanoate (triethylhexanoin) (IOB=0.35), tripropylene glycol dipivalate (IOB=0.52), pentaerythrityl tetra-2-ethylhexanoate (IOB=0.35), diethylhexyl succinate (IOB=0.32), neopentyl glycol diethylhexanoate (IOB=0.32), trimethylolpropane triethylhexanoate (IOB=0.33), pentaerythrityl tetraethylhexanoate (IOB=0.35), and diisopropyl adipate (IOB=0. Examples of ester oils include diisostearyl malate (IOB=0.46), dipropylene glycol dineopentanoate (IOB=0.52), propylene glycol dicaprylate (IOB=0.32), and glyceryl triethylhexanoate (IOB=0.36). Of these, diisopropyl bacate (IOB=0.4), glyceryl tri-2-ethylhexanoate (triethylhexanoin) (IOB=0.35), tripropylene glycol dipivalate (IOB=0.52), pentaerythrityl tetra-2-ethylhexanoate (IOB=0.35), and diethylhexyl succinate (IOB=0.32) are preferred. These ester oils may be used alone or in combination of two or more.

[0025] By including an ester oil in the water-in-oil composition, the balance of emulsification between the oil-based component and the water-based component can be adjusted, and dissolution of the ultraviolet absorber can be promoted.

[0026] As is clear from the above-mentioned specific examples of (B) polar oil, (B) polar oil may be either solid or liquid at room temperature.

[0027] <(C) Non-polar oil> (C) Nonpolar oil refers to an oil-based component with relatively low polarity, and may be, for example, an oil-based component with an IOB of less than 0.3. Examples of (C) nonpolar oil include hydrocarbon oils, nonpolar silicone oils, and nonpolar ester oils. In this embodiment, the nonpolar oil preferably has a structure with an alkyl side chain. Here, the "side chain" refers to the chain portion directly bonded to the main chain, which is the longest linear portion of the chain molecule. By incorporating a (C) nonpolar oil with an alkyl side chain, the gel-like properties of the water-in-oil composition can be stabilized for a long period of time.

[0028] (C) Non-polar oil may be a monomer or a polymer (including an oligomer). Whether (C) Non-polar oil is a monomer or a polymer, the number of carbon atoms in one alkyl side chain may be 1, preferably 2 or more, more preferably 3 or more, and even more preferably 5 or more. In addition, the alkyl group in the alkyl side chain may be a linear or branched alkyl group.

[0029] When the (C) nonpolar oil is a monomer, the number of alkyl side chains bonded to the nonpolar oil in one molecule may be 1, or preferably 2 or more, more preferably 3 or more, and even more preferably 5 or more. When the (C) nonpolar oil is a polymer, the number of alkyl side chains in one monomer unit may be 1 or 2 or more.

[0030] Furthermore, when (C) nonpolar oil is a monomer, the total number of carbon atoms contained in the alkyl side chains in one molecule (when there are two or more alkyl side chains, the total number of carbon atoms contained in all of the alkyl side chains) may be 1, preferably 2 or more, more preferably 3 or more, and preferably 10 or less, more preferably 8 or less. When (C) nonpolar oil is a polymer, the total number of carbon atoms contained in the alkyl side chains in one monomer unit may be 1, preferably 2 or more, more preferably 3 or more, even more preferably 5 or more, and preferably 20 or less, more preferably 10 or less.

[0031] When the (C) non-polar oil is a hydrocarbon oil having an alkyl side chain, it may be an aliphatic unsaturated hydrocarbon oil that is liquid or solid at room temperature.

[0032] Specific examples of hydrocarbon oils having alkyl side chains include hydrogenated polydecene, hydrogenated polyisobutene, squalane, isohexadecane, and isododecane. Of these, hydrogenated polydecene is preferred. These hydrocarbon oils may be used alone or in combination of two or more.

[0033] Non-polar silicones having alkyl side chains include silicone compounds in which alkyl side chains are introduced into chain polysiloxanes, such as dimethylpolysiloxanes. Although functional groups other than alkyl may be introduced, it is preferable that the functional groups introduced as side chains are only alkyl. Furthermore, silicones without aromatic functional groups are preferable.

[0034] A specific example of a non-polar silicone having an alkyl side chain is caprylyl methicone. These silicone oils may be used alone or in combination of two or more.

[0035] When the (C) non-polar oil is a non-polar ester oil, a specific example of the non-polar ester oil is cetyl 2-ethylhexanoate.

[0036] The content of the (C) nonpolar oil may be preferably 5% by mass or more and 40% by mass or less, more preferably 10% by mass or more and 30% by mass or less, based on the total amount of the water-in-oil composition. By setting the content of the (C) nonpolar oil within this range, the gel-like properties of the water-in-oil composition can be stabilized for a long period of time, and the tactile feel upon application can be improved.

[0037] Furthermore, the ratio of the content of the (C) nonpolar oil to the content of the (B) polar oil ([content of the (C) nonpolar oil] / [content of the (B) polar oil)]) may be preferably 0.25 or more and 4 or less, more preferably 0.3 or more and 3.5 or less, and even more preferably 0.4 or more and 3.0 or less. When the ratio of the content of the (C) nonpolar oil to the content of the (B) polar oil is within the above range, the balance between the (C) nonpolar oil and the (B) polar oil is improved, the oil phase can be stably gelled, and the gelled state of the water-in-oil composition is well maintained.

[0038] <(D1) Polyoxyethylene hydrogenated castor oil> (D1) Polyoxyethylene (POE) hydrogenated castor oil (polyoxyethylene hydrogenated castor oil) is obtained by adding hydrogen and polyethylene glycol (PEG) to castor oil. (D1) Polyoxyethylene hydrogenated castor oil can function as a nonionic surfactant, and in the water-in-oil composition of this embodiment, it has a high function of dispersing (A) the organically modified clay mineral in the oil phase.

[0039] The HLB value of the polyoxyethylene hydrogenated castor oil (D1) used in this embodiment is not particularly limited. However, in order to maintain a good water-in-oil emulsified state, it may preferably be 12 or less. The "HLB value" refers to the HLB (Hydrophilic-Lipophilic Balance) value, which indicates the degree of affinity of a surfactant for water and oil, and can be calculated using Griffin's formula (HLB value = molecular weight of glycerin portion × 20 / total molecular weight).

[0040] The number of moles of polyoxyethylene added to (D1) polyoxyethylene hydrogenated castor oil may be preferably 1 or more and 60 or less, more preferably 5 or more and 40 or less.

[0041] Specific examples of (D1) polyoxyethylene hydrogenated castor oil include POE(5) hydrogenated castor oil, POE(10) hydrogenated castor oil, POE(20) hydrogenated castor oil, POE(30) hydrogenated castor oil, POE(40) hydrogenated castor oil, and POE(60) hydrogenated castor oil, and among these, POE(10) hydrogenated castor oil is preferred.

[0042] The polyoxyethylene hydrogenated castor oil (D1) mentioned above can be used singly or in combination of two or more.

[0043] The content of (D1) polyoxyethylene hydrogenated castor oil may be preferably 0.05% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 5% by mass or less, based on the total amount of the water-in-oil composition. When the content of (D1) polyoxyethylene hydrogenated castor oil is within the above range, the gelling or thickening action of (A) organically modified clay mineral is promoted, and the gel-like properties of the water-in-oil composition can be stably maintained.

[0044] Furthermore, the ratio of the content of (D1) polyoxyethylene hydrogenated castor oil to the content of (A) organically modified clay mineral ([content of (D1) polyoxyethylene hydrogenated castor oil] / [content of (A) organically modified clay mineral]) may preferably be 0.1 or more and 5 or less, more preferably 0.5 or more and 2 or less. When the ratio of the content of (D1) polyoxyethylene hydrogenated castor oil to the content of (A) organically modified clay mineral is within the above range, gelation of the oil-based components is promoted, and the properties of the water-in-oil composition as a whole are more likely to be maintained in a gel state.

[0045] <(D2) Emulsifying surfactant> Furthermore, the water-in-oil composition according to this embodiment contains, as an emulsifying surfactant (D2), an emulsifying surfactant which is a compound having an alkyl side chain containing 10 or more carbon atoms, or a compound having a fatty acid side chain containing 10 or more carbon atoms, or a polyoxyethylene adduct thereof. The emulsifying surfactant (D2) mainly promotes emulsification of the oil-based component and the aqueous component, and has a high function of maintaining the emulsified state over time.

[0046] More specifically, the (D2) emulsifying surfactant may be a silicone-based emulsifying surfactant having an alkyl side chain with 10 or more carbon atoms. The alkyl group in the alkyl side chain may be a linear or branched alkyl group. Furthermore, the silicone-based emulsifying surfactant may have a polyether side chain (a functional group side chain derived from polyethylene glycol or polypropylene glycol) in addition to the alkyl side chain, and may also have a silicone side chain.

[0047] When the (D2) emulsifying activator is a silicone-based emulsifying activator, the number of carbon atoms in one alkyl side chain may be preferably 10 or more and 20 or less, more preferably 12 or more and 15 or less. The alkyl group in the alkyl side chain may be a linear or branched alkyl group.

[0048] Specific examples of silicone-based emulsifying surfactants include cetyl PEG / PPG-10 / 1 dimethicone and lauryl PEG-9 polydimethylsiloxyethyl dimethicone.

[0049] The emulsifying surfactant (D2) may be a fatty acid ester of glycerin or polyglycerin having a fatty acid side chain with 10 or more carbon atoms, or a polyoxyethylene adduct thereof. In this specification, the fatty acid side chain refers to a functional group derived from a fatty acid or a fatty acid condensate, and more specifically, may be a functional group in which a hydrogen atom has been removed from the carboxyl group of a fatty acid, or a functional group in which a hydrogen atom has been removed from the terminal carboxyl group of a condensate of an unsaturated fatty acid or a hydroxy fatty acid.

[0050] When the fatty acid side chain is derived from a fatty acid monomer, the number of carbon atoms in the fatty acid may be preferably 10 to 24, more preferably 14 to 22, and even more preferably 16 to 20. When the fatty acid side chain is derived from a fatty acid condensate, the number of carbon atoms in the fatty acid (fatty acid before condensation) may also be 10 to 24, more preferably 14 to 22, and even more preferably 16 to 20.

[0051] When the emulsifying surfactant (D2) is a polyoxyethylene adduct, the number of moles of polyoxyethylene may be preferably 5 or more and 60 or less, more preferably 10 or more and 40 or less.

[0052] When the emulsifying surfactant (D2) is a polyoxyethylene adduct, polyoxyethylene may be added to the fatty acid side chain itself, but the fatty acid side chain may not have a polyethylene glycol chain branched therefrom. Alternatively, the fatty acid constituting the fatty acid side chain may be an unsubstituted fatty acid, more specifically, a fatty acid having no hydroxyl group.

[0053] When the (D2) emulsifying surfactant is a fatty acid ester of glycerin or polyglycerin having a fatty acid side chain containing 10 or more carbon atoms, or a polyoxyethylene adduct thereof, examples thereof include polyoxyethylene adducts of fatty acid triglycerides, such as POE(10) glycerin triisostearate and POE(15) glycerin triisostearate; fatty acid esters of polyglycerin, such as polyglyceryl-10 pentaoleate, polyglyceryl-2 triisostearate, and polyglyceryl-10 pentastearate; and esters of condensates of hydroxy fatty acids with polyglycerin, such as polyglyceryl-6 polyricinoleate and polyglyceryl-6 polyhydroxystearate.

[0054] The HLB value of the emulsifying surfactant (D2) may be preferably 9 or less, more preferably 7.5 or less, and even more preferably 6 or less.

[0055] Whether the emulsifying surfactant (D2) is a compound having an alkyl side chain containing 10 or more carbon atoms, or a compound having a fatty acid side chain containing 10 or more carbon atoms or a polyoxyethylene adduct thereof, the content of the emulsifying surfactant (D2) may be preferably from 0.05 to 10% by mass, more preferably from 0.1 to 5% by mass, based on the total amount of the water-in-oil composition. By including the emulsifying surfactant (D2) in the above range, the emulsified state of the oil component and the aqueous component can be maintained favorably for a long period of time.

[0056] <Other ingredients> The water-in-oil composition of this embodiment contains water, which is commonly used in topical compositions, in addition to the above-mentioned components (A) to (D2). Purified water, ion-exchanged water, tap water, etc. can be used as the water. The water content in this embodiment may be preferably 50% by mass or more and 80% by mass or less, more preferably 55% by mass or more and 75% by mass or less, based on the total amount of the water-in-oil composition.

[0057] Furthermore, the water-in-oil composition may contain optional components other than the above-mentioned components (A) to (D2) and water, to the extent that the effects of this embodiment are not impaired. For example, the water-based component may contain a water-soluble alcohol, and the oil-based component may contain a higher alcohol, liquid oil, solid oil, wax, higher fatty acid, fragrance, etc.

[0058] The water-in-oil composition of this embodiment may contain wax. Wax is an oil-based component that is solid or semi-solid at room temperature and includes hydrocarbons, neutral fats, higher fatty acids, and esters of higher fatty acids and higher alcohols. Wax may enhance the stability of the formulation of the composition. From the viewpoint of achieving a light feel when using the resulting water-in-oil composition, the wax content should be small, preferably 1% by mass or less, more preferably less than 0.5% by mass, and even more preferably 0.1% by mass or less, based on the total amount of the water-in-oil composition. Furthermore, from the viewpoint of eliminating the need for heating during production, it is preferable that the wax content be 0% by mass, i.e., the water-in-oil composition does not contain wax. From another perspective, the water-in-oil composition of this embodiment can form a stable gel by blending the above-mentioned components (A), (B), (C), (D1), and (D2), so that a stable water-in-oil composition can be obtained without blending wax.

[0059] The water-in-oil composition of this embodiment may contain a cyclic silicone or a cyclic polysiloxane (e.g., octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, etc.). However, if a cyclic silicone is contained, the content thereof may be preferably 1% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.1% by mass or less, and even more preferably 0.01% by mass or less, relative to the total amount of the water-in-oil composition. It is also preferable that the water-in-oil composition is substantially free of, or does not contain, a cyclic silicone. In this specification, the phrase "substantially free of" or "substantially free of" a specified component refers to a form in which the specified component is inevitably mixed in during the acquisition of raw materials or the production process of the composition.

[0060] The composition may also contain surfactants such as cationic surfactants, anionic surfactants, nonionic surfactants other than those mentioned above, amphoteric surfactants, etc. Furthermore, the composition may also contain thickeners, moisturizers, transdermal absorption inhibitors, chelating agents, pigments, antioxidants, preservatives, anti-inflammatory agents, whitening agents, plant extracts, activators, blood circulation promoters, and antiseborrheic agents.

[0061] Furthermore, the water-in-oil composition according to this embodiment may contain an organic or inorganic powder. Specific examples of inorganic powders include titanium oxide, zinc oxide, cerium oxide, talc, silica, mica, sericite, kaolin, titanium mica, black iron oxide, yellow iron oxide, red iron oxide, ultramarine, Prussian blue, chromium oxide, and chromium hydroxide. The composition may also be a composite powder in which particles other than titanium oxide are coated with titanium oxide. The composition may also contain a powder (average particle size of 1 μm to 20 μm) of a biodegradable resin such as a polyhydroxyalkanoate, such as polyhydroxybutyrate or poly(3-hydroxybutyrate-co-3-hydroxyvalerate).

[0062] <Application> The use of the water-in-oil composition of this embodiment is not particularly limited, but it is suitably used in the fields of cosmetics, quasi-drugs, and personal care products as an external preparation or a skin application agent, particularly as a cosmetic. The oil-in-water composition of this embodiment may also be a sunscreen for the purpose of UV protection, or a cosmetic with enhanced UV protection function, for example, a basic cosmetic such as a foundation, or a makeup cosmetic.

[0063] [Second embodiment] The composition according to the second embodiment contains (A) an organically modified clay mineral, (B) 3% by mass or more of a polar oil with an IOB of 0.3 or more, and (C) a non-polar oil having an alkyl side chain, as in the first embodiment, but contains (D) a fatty acid ester of polyoxyethylene hydrogenated castor oil instead of (D1) polyoxyethylene hydrogenated castor oil and (D2) emulsifying activator used in the first embodiment. The inclusion of (D) a fatty acid ester of polyoxyethylene hydrogenated castor oil promotes uniform dispersion of (A) the organically modified clay mineral in the oil component and maintains a good emulsification balance between the oil component and the water component of the water-in-oil composition, thereby stabilizing the properties of the water-in-oil composition over an extended period of time.

[0064] The fatty acid constituting the (D) fatty acid ester of polyoxyethylene hydrogenated castor oil may be a higher fatty acid, and the number of carbon atoms therein may be preferably 13 to 25, more preferably 16 to 20. The fatty acid may have a linear or branched structure, but is preferably a branched fatty acid, and isostearic acid is particularly preferred.

[0065] The number of moles of polyoxyethylene added to the fatty acid ester of (D) polyoxyethylene hydrogenated castor oil may be preferably 5 or more and 60 or less, more preferably 10 or more and 40 or less.

[0066] Specific examples of (D) fatty acid esters of polyoxyethylene hydrogenated castor oil include polyoxyethylene adducts of triisostearic acid such as PEG-10 hydrogenated castor oil triisostearate and PEG-20 hydrogenated castor oil triisostearate.

[0067] The content of (D) polyoxyethylene hydrogenated castor oil fatty acid ester may be preferably 0.1% by mass to 15% by mass, more preferably 1% by mass to 10% by mass, based on the total amount of the water-in-oil composition. By containing it in the above range, the emulsified state of the oil component and the water component can be maintained well for a long period of time.

[0068] Furthermore, the ratio of the content of the fatty acid ester of (D) polyoxyethylene hydrogenated castor oil to the content of (A) organically modified clay mineral ([content of (D) polyoxyethylene hydrogenated castor oil] / [content of (A) organically modified clay mineral]) may preferably be 0.2 or more and 10 or less, more preferably 1 or more and 5 or less. When the ratio of the content of (D) polyoxyethylene hydrogenated castor oil to the content of (A) organically modified clay mineral is within the above range, gelation of the oil-based component is promoted, the emulsification state of the oil-based component and the water-based component is improved, and the properties of the water-in-oil composition as a whole are more likely to be maintained in a gel state.

[0069] In the water-in-oil composition according to the second embodiment, other ingredients that can be blended and uses of the composition are the same as those described in the first embodiment. [Example]

[0070] Compositions having the formulations shown in Tables 1 and 2 were prepared by conventional methods. Specifically, a polar oil, a non-polar oil, polyoxyethylene hydrogenated castor oil, and an emulsifying activator were mixed together, followed by the addition of an organically modified clay mineral and further mixing, and then water was added to obtain the compositions of Examples 1 to 11 and Comparative Examples 1 to 5. Similarly, a polar oil, a non-polar oil, and a polyoxyethylene hydrogenated castor oil fatty acid ester were mixed together, followed by the addition of an organically modified clay mineral and further mixing, and then water was added to obtain the composition of Example 12. The gelation state of each of Examples 1 to 12 and Comparative Examples 1 to 5 was evaluated. Tables 1 and 2 also show the evaluation results.

[0071] <Evaluation of gelation stability> The gelation stability of each composition was evaluated visually according to the following criteria. A: It was confirmed that the gel was in a good state and remained stable even after 28 days. B: It was confirmed that the gel was in a good state and remained stable even after 7 days. C: It was confirmed that the gel was in a good state and that stability was maintained even after one day had passed. D: It did not gel.

[0072] [Table 1]

[0073] [Table 2]

[0074] Specific formulation examples (Formulation Examples 1 to 4) of the water-in-oil composition according to this embodiment are shown below.

[0075] [Table 3]

[0076] [Table 4]

[0077] [Table 5]

[0078] [Table 6]

[0079] This application claims priority to Japanese Patent Application No. 2021-022875, filed on February 16, 2021, the entire contents of which are incorporated herein by reference.

Claims

1. (A) organically modified clay minerals; (B) 3% by mass or more of a polar oil having an IOB of 0.3 or more; (C) a non-polar oil that is one or more of a non-polar silicone oil having an alkyl side chain with 2 to 20 carbon atoms and a non-polar hydrocarbon oil having an alkyl side chain; (D1) polyoxyethylene hydrogenated castor oil, and (D2) A water-in-oil composition containing an emulsifying activator which is a silicone having an alkyl side chain containing from 10 to 20 carbon atoms, or a fatty acid ester of glycerin or polyglycerin having a fatty acid side chain containing from 10 to 24 carbon atoms, or a polyoxyethylene adduct thereof, wherein the fatty acid side chain is a group derived from a fatty acid or a group derived from a condensate of an unsaturated fatty acid or a hydroxy fatty acid.

2. 2. The water-in-oil composition according to claim 1, wherein the ratio of the content of (D1) polyoxyethylene hydrogenated castor oil to the content of (A) organically modified clay mineral is 0.1 or more and 5 or less.

3. 3. The water-in-oil composition according to claim 1 or 2, wherein the average number of moles of ethylene oxide added in the polyoxyethylene hydrogenated castor oil (D1) is 5 to 60.

4. 4. The water-in-oil composition according to claim 1, wherein the wax content is 0.1% by mass or less.

5. (A) organically modified clay minerals; (B) 3% by mass or more of a polar oil having an IOB of 0.3 or more; (C) a non-polar oil that is one or more of a non-polar silicone oil having an alkyl side chain containing 2 to 20 carbon atoms and a non-polar hydrocarbon oil having an alkyl side chain containing 2 to 20 carbon atoms; and (D) Fatty acid ester of polyoxyethylene hydrogenated castor oil Contains A water-in-oil composition having a wax content of 0.1% by mass or less.

6. 6. The water-in-oil composition according to claim 5, wherein the (D) fatty acid ester of polyoxyethylene hydrogenated castor oil is a triester of a branched fatty acid having from 13 to 25 carbon atoms.

7. 7. The water-in-oil composition according to claim 5 or 6, wherein the ratio of the content of (D) the fatty acid ester of polyoxyethylene hydrogenated castor oil to the content of (A) the organically modified clay mineral is 0.2 or more and 10 or less.

8. 8. The water-in-oil composition according to claim 5, wherein the average number of moles of ethylene oxide added in the fatty acid ester of (D) polyoxyethylene hydrogenated castor oil is 5 to 60.

9. 9. The water-in-oil composition according to claim 1, wherein the polar oil (B) comprises an ultraviolet absorber.

10. 10. The water-in-oil composition according to claim 1, wherein the non-polar oil (C) is one or more selected from the group consisting of hydrogenated polydecene, caprylyl methicone, and squalane.

11. 11. The water-in-oil composition of claim 10, wherein the (C) non-polar oil is hydrogenated polydecene.

12. 12. The water-in-oil composition according to claim 1, wherein the ratio of the content of the non-polar oil (C) to the content of the polar oil (B) is 0.25 or more and 4 or less.

13. 13. The water-in-oil composition according to claim 1, wherein the content of cyclic silicone is 1% by mass or less.

Images