oil-water mixture

Abstract

A water-in-oil composition containing (a) an ultraviolet absorber having a silicone skeleton, (b) a volatile acyclic silicone oil, (c) no more than 5 mass% of a cyclic silicone, (d) a hydrophobic silica powder, and (e) a hydrophilic powder.

Description

[Technical Field]

[0001] The present invention relates to an oil-water mixture composition. [Background technology]

[0002] Water-in-oil compositions have excellent occlusive and moisturizing properties and are therefore widely used as compositions for application to the skin, particularly as cosmetics and personal care products. Water-in-oil compositions may be provided as products in a homogenized (emulsified) state, or may be provided in a state in which some of the ingredients, such as powder, have settled, and the user homogenizes the composition by shaking the container containing the composition when using it.

[0003] Among the properties of water-in-oil compositions, homogenization properties (good homogenization state) and usability are particularly important, and therefore various formulation designs have been investigated to improve these properties, and much trial and error has been carried out. For example, water-in-oil compositions that provide a good emulsified state and a good usability are known that contain a specific silicone oil and organopolysiloxane elastomer spherical powder (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-120525 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in recent years, due to the growing concern about the natural environment, there is a demand for compositions with reduced amounts of certain ingredients, particularly compositions with reduced amounts of certain silicone oils, which has led to the need to design formulations under conditions where restrictions are imposed on the ingredients that can be used.

[0006] In view of the above, an object of one aspect of the present invention is to provide a water-in-oil composition that is excellent in homogenization properties and feeling in use, and that is also environmentally friendly. [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 ultraviolet absorber having a silicone skeleton, (b) a volatile acyclic silicone oil, (c) 5 mass% or less of a cyclic silicone, (d) a hydrophobic silica powder, and (e) a hydrophilic powder. [Effects of the Invention]

[0008] One aspect of the present invention can provide a water-in-oil composition that is excellent in homogenization properties and feel when used, and that is also environmentally friendly. 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 specific embodiments described below.

[0010] <Water-in-oil composition> One embodiment of the present invention is a water-in-oil composition containing (a) an ultraviolet absorber having a silicone skeleton, (b) a volatile acyclic silicone oil, (c) 5% by mass or less of a cyclic silicone, (d) a hydrophobic silica powder, and (e) a hydrophilic powder. The water-in-oil composition is a composition containing an emulsifiable oil-based component and an aqueous component. In this specification, the water-in-oil composition may be in a form that maintains a homogenized state (also referred to as a non-separated type), or in a form in which some of the components separate or settle upon standing but can be homogenized by stirring the composition upon use (also referred to as a separated type). The water-in-oil composition of this embodiment may be one that can be applied to the skin in a water-in-oil emulsion state upon use. Water-in-oil compositions have high occlusive and moisturizing effects, making them suitable for use as compositions for application to the skin.

[0011] A separation-type composition may become heterogeneous when left standing for a predetermined period of time or longer. A separation-type composition may be in a form in which, for example, at least a portion of a heavy component, such as a powder, settles upon standing. Alternatively, the composition may be in a form in which it separates into an upper layer containing mainly oil-based components and a lower layer containing mainly water-based components (layer-separated type). In the case of the layer-separated type, at least one of the separated layers may be a water-in-oil emulsion. Separation-type compositions may also include those in which the settling of components or layer separation cannot be seen with the naked eye.

[0012] The water-in-oil composition according to this embodiment has good homogenization properties. In this specification, "homogenization properties" refers to the water-in-oil composition being a well-homogenized (emulsified or dispersed) emulsion, or being able to be a well-homogenized (emulsified or dispersed) water-in-oil emulsion through the user's stirring action. Therefore, in the case of a non-separated type, good homogenization properties refer to the composition being homogenized at the stage of providing the product and stably maintaining this homogenized state. In the case of a separated type, good homogenization properties refer to the composition being well-homogenized (highly redispersible) through stirring by the user during use. In the case of a separated type, the stirring action by the user during use is not particularly limited as long as it fluidizes the mixture of the emulsifiable oil-based component and the aqueous component and promotes emulsification or dispersion. For example, the stirring action may be, for example, shaking the container containing the water-in-oil composition by hand with the lid closed. In this case, a stirring ball such as a steel ball may be placed in the container.

[0013] The emulsification mechanism between the oil-based component and the aqueous component is complex, and ingenuity is required in formulating a water-in-oil composition to obtain good homogenization properties. Furthermore, in recent years, there has been a demand for water-in-oil compositions with improved UV protection function, and a formula containing a relatively large amount of UV absorber in the water-in-oil composition is required. Since most UV absorbers are polar oils, the addition of a UV absorber can easily disrupt the balance between the oil-based component and the aqueous component, making formulating a water-in-oil composition even more difficult. However, according to this embodiment, even when a UV absorber is added, good emulsification of the oil-based component and the aqueous component can be obtained, that is, a composition with excellent homogenization properties can be obtained.

[0014] Furthermore, the water-in-oil composition of this embodiment can provide a good feel when used. In this specification, the feel when used includes the feel during application (the feel felt when applying the composition to the skin) and the feel after application (the feel felt after applying the composition to the skin). The feel during application may be the feel felt by the skin when applying the composition to the skin, or the feel felt by the fingers when applying the composition with fingers or the like, or both. The feel after application may be the feel felt by the skin after applying the composition to the skin, or the feel felt by the skin and / or fingers or the like when touching or rubbing the composition with fingers or the like again after applying the composition to the skin.

[0015] The viscosity of the water-in-oil composition according to this embodiment may be preferably 300 to 10,000 mPa·s, more preferably 500 to 8000 mPa·s.

[0016] <(a) UV absorber having a silicone skeleton> The (a) UV absorber having a silicone skeleton is not particularly limited as long as it has a silicone skeleton in its structure and is usable in compositions for application to the skin. The silicone skeleton refers to a structure having a siloxane bond. The (a) UV absorber having a silicone skeleton may be a polymeric compound or a low molecular weight compound. In the case of a polymeric compound, its number average molecular weight may be preferably 2,000 or more and 10,000 or less, more preferably 3,000 or more and 8,000 or less. Furthermore, the (a) UV absorber having a silicone skeleton may be a solid or a liquid at room temperature.

[0017] (a) The UV absorber having a silicone skeleton may be, for example, one or more of a cinnamic acid derivative having a silicone skeleton, a phenylbenzotriazole derivative having a silicone skeleton, and a silicone compound having a benzalmalonate functional group. Specific examples of (a) the UV absorber having a silicone skeleton include polysilicone-15 (dimethicone diethyl benzalmalonate), methyl bis(trimethylsiloxy)silylisopentyl trimethoxycinnamate, and drometrizole trisiloxane. Among these, the polymeric compound polysilicone-15 is preferred. These specific UV absorbers can be used alone or in combination of two or more.

[0018] By including (a) an ultraviolet absorber having a silicone skeleton in the in-oil mixed composition of this embodiment, the ultraviolet absorption effect is improved, and the feeling of use during and after application is also improved, particularly reducing the squeaky feeling after application.

[0019] The content of (a) the UV absorber having a silicone skeleton in the composition of this embodiment 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 aqueous mixture composition. By setting the content of (a) the UV absorber having a silicone skeleton within this range, the feel during and after application can be improved.

[0020] The oil-water mixture composition according to this embodiment may further contain an ultraviolet absorber that does not have a silicone skeleton. The type of ultraviolet absorber that does not have a silicone skeleton is not particularly limited, and for example, one or more of benzoic acid derivatives, salicylic acid derivatives, cinnamic acid derivatives, dibenzoylmethane derivatives, β,β-diphenylacrylate derivatives, benzophenone derivatives, benzylidene camphor derivatives, phenylbenzimidazole derivatives, triazine derivatives, phenylbenzotriazole derivatives, anthranil derivatives, imidazoline derivatives, benzalmalonate derivatives, and 4,4-diarylbutadiene derivatives can be used.

[0021] UV absorbers absorb different wavelengths of light depending on their structure. Therefore, by using multiple UV absorbers with different structures, particularly multiple UV absorbers with different basic derivative structures, the absorbable wavelength range can be broadened, thereby improving UV protection function. UV absorbers without a silicone skeleton can be used in combination with, for example, cinnamic acid derivatives, β,β-diphenylacrylate derivatives, triazine derivatives, benzoic acid derivatives, and salicylic acid derivatives. Specific examples of such combinations include ethylhexyl methoxycinnamate, octocrylene, bisethylhexyloxyphenol methoxyphenyl triazine (anisotriazine), diethylaminohydroxybenzoyl hexyl benzoate, and ethylhexyl salicylate.

[0022] Regardless of whether or not a silicone skeleton is present, the total amount of UV absorbers incorporated into a water-in-oil composition may be preferably 5% by mass or more and 40% by mass or less, more preferably 8% by mass or more and 30% by mass or less, relative to the total amount of the water-in-oil composition. By making the total amount of UV absorbers 5% by mass or more, a high UV protection effect can be obtained, and by making it 30% by mass or less, the amount of polar oil can be reduced, thereby obtaining a good water-in-oil state and suppressing stickiness of the composition, thereby improving the feel when used.

[0023] Furthermore, the ratio of the content of (a) UV absorber having a silicone skeleton to the total content of UV absorbers can be preferably 1% by mass or more and 20% by mass or less, more preferably 3% by mass or more and 15% by mass or less. By setting the ratio of (a) UV absorber having a silicone skeleton to the total content of UV absorbers to be 1% by mass or more, the feeling of use of the water-in-oil composition, particularly the squeaky feeling after use, can be reduced, and by setting it to be 20% by mass or less, a well-balanced combination with UV absorbers that absorb light in different wavelength ranges can be achieved, thereby improving the UV protection effect over a wide wavelength range.

[0024] <(b) Volatile acyclic silicone oil> (b) The volatile acyclic silicone oil is an oil that is volatile at 25°C under 1 atmospheric pressure, and more specifically, may be an oil with a boiling point of 250°C or lower under 1 atmospheric pressure. When the water-in-oil composition contains a volatile acyclic silicone oil, the sensation during and / or after application is improved, and in particular stickiness, squeaking, etc. are suppressed, and the composition can have an improved smooth feel and be more easily absorbed into the skin.

[0025] The volatile acyclic silicone oil is preferably a chain polysiloxane. Specific examples include dimethylpolysiloxane (dimethicone), such as decamethyltetrasiloxane, dodecamethylpentasiloxane, tetradecamethylhexasiloxane, and hexadecamethylheptasiloxane. Among these, dimethylpolysiloxane (dimethicone) is preferred.

[0026] The kinematic viscosity of the (b) volatile acyclic silicone oil at 25° C. may be preferably 5 cSt or less, more preferably 2 cSt or less. Use of a silicone oil having the above kinematic viscosity can further improve the feel upon use.

[0027] (b) The volatile acyclic silicone may be used alone or in combination of two or more different types. In this case, two or more types of silicones having similar monomer units but different in at least one property (weight average molecular weight, kinematic viscosity, other rheological property) may be used in combination.

[0028] The content of (b) volatile acyclic silicone oil may be preferably 5% by mass or more and 30% by mass or less, more preferably 10% by mass or more and 25% by mass or less, based on the total amount of the water-in-oil composition. By having the content of (b) volatile acyclic silicone oil at 5% by mass or more, it is possible to suppress oily stickiness and improve the smooth feeling. Furthermore, by having the content at 30% by mass or less, good homogenization properties can be obtained. In particular, in the case of a phase-separated water-in-oil composition, good homogenization can be achieved by the user's usual stirring operation, i.e., high redispersibility can be obtained.

[0029] <(c) Cyclic silicone> In the water-in-oil composition of this embodiment, it is preferable that the content of cyclic silicone is low. The content of cyclic silicone may be 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less, even more preferably less than 0.1% by mass, even more preferably less than 0.05% by mass, and even more preferably less than 0.01% by mass, based on the total amount of the water-in-oil composition. Furthermore, it is preferable that the water-in-oil composition of this embodiment does not substantially contain cyclic silicone or does not contain it at all. In this specification, "substantially does not contain" a specific component means that it is acceptable for the specific component to be unintentionally or unavoidably generated or mixed in during the manufacturing process.

[0030] In this embodiment, by setting the content of (c) cyclic silicone to 5% by mass or less as described above, it is possible to provide an environmentally friendly product. Furthermore, according to this embodiment, even if the content of cyclic silicone is reduced, it is possible to obtain a water-in-oil composition that has excellent homogenization properties and usability.

[0031] The cyclic silicone may be a cyclic polysiloxane, preferably a cyclic polysiloxane having 4 to 7 silicon atoms, which is either unsubstituted or substituted with an alkyl group or an alkoxy group. Specific examples of the cyclic silicone include octamethylcyclotetrasiloxane (cyclotetrasiloxane), decamethylcyclopentasiloxane (cyclopentasiloxane), and dodecamethylcyclohexasiloxane (cyclohexasiloxane).

[0032] It is also preferred that the water-in-oil composition contains substantially no, or no, one or more selected from octamethylcyclotetrasiloxane (cyclotetrasiloxane), decamethylcyclopentasiloxane (cyclopentasiloxane), and dodecamethylcyclohexasiloxane (cyclohexasiloxane).Furthermore, it is preferred that the water-in-oil composition contains substantially no, or no, cyclic polysiloxane having 4 to 7 silicon atoms, which is unsubstituted or substituted with an alkyl group or an alkoxy group.

[0033] <(d) Hydrophobic silica powder> The (d) hydrophobic silica powder may be silica powder whose surface has been subjected to a hydrophobic treatment. By including the (d) hydrophobic silica powder in the water-in-oil composition, the feel during and after application can be improved, particularly reducing the squeaky feeling. The smooth feel during application can also be improved. Furthermore, even if the ingredients are limited in consideration of the natural environment, a product with excellent feel during application and homogenization properties can be provided. In particular, the (d) hydrophobic silica powder can improve the feel during and / or after application, particularly reducing the oily, sticky feeling. Furthermore, homogenization properties (redispersibility in the case of a phase-separated type) can also be improved.

[0034] The method for hydrophobizing silica is not particularly limited, and examples thereof include silicone treatment, fatty acid treatment, fatty acid soap treatment, fatty acid ester treatment, and higher alcohol treatment.

[0035] Examples of silicone treatments include treatments with silicone oils such as methylhydrogenpolysiloxane, dimethylpolysiloxane, and methylphenylpolysiloxane; alkylsilanes such as methyltrimethoxysilane, ethyltrimethoxysilane, hexyltrimethoxysilane, and octyltrimethoxysilane; and fluoroalkylsilanes such as trifluoromethylethyltrimethoxysilane and heptadecafluorodecyltrimethoxysilane. Examples of fatty acid treatments include treatments with palmitic acid, isostearic acid, stearic acid, lauric acid, myristic acid, behenic acid, oleic acid, rosin acid, and 12-hydroxystearic acid. Examples of fatty acid soap treatments include treatments with aluminum stearate, calcium stearate, and 12-hydroxystearic acid. Examples of fatty acid ester treatments include treatments with dextrin fatty acid esters, cholesterol fatty acid esters, sucrose fatty acid esters, and starch fatty acid esters. Of the above treatments, treatment with dimethylpolysiloxane (dimethicone) is preferred.

[0036] More specific treatment methods include a method of hydrophobizing and drying a wet-process silica sol, a method of adding a silazane compound or a monofunctional silane compound to a hydrophilic silica particle dispersion to triorganosilylate the silica particle surface, a method of hydrolyzing and condensing a tetrafunctional silane compound to obtain a hydrophilic silica particle dispersion, substituting the hydrophilic organic solvent with water, subsequently hydrophobizing the dispersion with a trifunctional silane compound, and then further substituting the dispersion medium with a ketone solvent to triorganosilylate the reactive groups remaining on the silica particle surface with a silazane compound or a monofunctional silane compound, and a method of hydrophobizing a hydrophilic silica particle dispersion by adding a trifunctional silane compound, and then adding a monofunctional silane compound.

[0037] (d) The average particle size of the hydrophobic silica powder is preferably 1 μm or more, and may be 1 μm or more and 10 μm or less. By setting the particle size of the hydrophobic silica powder within this range, the feeling of use of the composition is improved and handling during production is facilitated. In this specification, the average particle size of the powder or particle aggregate is a value measured using a particle size distribution analyzer by the laser diffraction / scattering method.

[0038] Furthermore, it is preferable to use (d) hydrophobic silica powder having an oil absorption of 10 ml / 100 g or more and 400 ml / 100 g or less, which can prevent oily stickiness during and / or after application of the water-in-oil composition.

[0039] The content of (d) hydrophobic silica powder may be preferably 0.1% by mass to 10% by mass, more preferably 0.5% by mass to 5% by mass, and even more preferably 1% by mass to 2% by mass, based on the total amount of the water-in-oil composition. By setting the content of (d) hydrophobic silica powder within the above range, the smooth feeling during and / or after application is improved, and homogenization properties are also improved.

[0040] <(e) Hydrophilic powder> The (e) hydrophilic powder may be a powder whose surface is originally hydrophilic, or may be a powder whose surface has been subjected to a hydrophilization treatment. When the water-in-oil composition contains the (e) hydrophilic powder, the homogenization characteristics of the water-in-oil emulsion system, particularly the redispersibility in the case of a phase-separated composition, are improved.

[0041] Specific examples of (e) hydrophilic powder include powders of silica (untreated silica), starch, cellulose, etc., and among these, silica powder is preferably used. Furthermore, (e) hydrophilic powder is preferably porous.

[0042] The average particle size of the (e) hydrophilic powder may be preferably 1 μm or more and 20 μm or less, more preferably 3 μm or more and 15 μm or less. By setting the average particle size of the (e) hydrophilic powder within the above range, the homogenization properties of the obtained water-in-oil composition are improved, and the feel during and / or after application is also improved. The average particle size of the (e) hydrophilic powder is preferably larger than the average particle size of the (d) hydrophobic silica powder.

[0043] The content of (e) hydrophilic powder may be preferably 1% by mass to 15% by mass, more preferably 3% by mass to 10% by mass, based on the total amount of the water-in-oil composition. By setting the content of (e) hydrophilic powder within the above range, the homogenization characteristics of the water-in-oil emulsion (redispersibility in the case of a phase-separated emulsion) are improved, and the feel when used is also improved.

[0044] The mass ratio of the content of (d) hydrophobic silica powder to the content of (e) hydrophilic powder may be preferably 1:0.5 to 1:15, more preferably 1:1 to 1:10. By setting the mass ratio of the two powders within the above range, it is possible to obtain a water-in-oil composition that is excellent in both usability and homogenization properties, even if the blending ingredients are limited, particularly in consideration of the natural environment.

[0045] <Other ingredients> The water-in-oil composition may contain other optional components as long as they do not interfere with the effects of this embodiment. Examples of other components include oil-based components other than the UV absorbers and silicone oils mentioned above, water-based components, surfactants, etc. The composition may also contain organically modified clay minerals, UV scattering agents (inorganic powders), pigments, and powders of biodegradable resins (average particle size of 1 μm to 20 μm) such as polyhydroxyalkanoates, including polyhydroxybutyrate and poly(3-hydroxybutyrate-co-3-hydroxyvalerate).

[0046] The other oil-based components may be oil-based components that are commonly used in compositions for application to the skin, and examples thereof include hydrocarbon oils, ester oils, higher fatty acids, higher alcohols, silicone oils other than the silicone oils described above, liquid oils and fats, solid oils and fats, waxes, fragrances, and oil phase thickeners.

[0047] Specific examples of hydrocarbon oils include isododecane, isohexadecane, isoparaffin, liquid paraffin, ozokerite, squalane, pristane, paraffin, ceresin, squalene, petrolatum, and microcrystalline wax, with isododecane being preferred.

[0048] Specific examples of ester oils include isononyl isononanoate, isopropyl myristate, cetyl 2-ethylhexanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, lanolin acetate, isocetyl stearate, isocetyl isostearate, cholesteryl 12-hydroxystearate, and ethylene glycol di-2-ethylhexanoate. , dipentaerythritol fatty acid ester, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, glyceryl di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, pentaerythritol tetra-2-ethylhexanoate, glyceryl tri-2-ethylhexanoate (triethylhexanoin), trimethylolpropane triisostearate, cetyl 2-ethylhexanoate Ethylhexyl Palmitate, Diethylhexyl Naphthalene Dicarboxylate, Benzoate (C12-15) Alkyl, Cetearyl Isononanoate, Tri(Caprylic / Capric) Glycerin, Butylene Glycol (Dicaprylic / Capric), Glyceryl Trimyristate, Tri-2-Heptylundecanoic Acid Glyceride, Castor Oil Fatty Acid Methyl Ester, Oleyl Oleate, Cetostearyl Alcohol Acetoglyceride, 2-Heptylundecyl Palmitate, Diisostearate, Adipate butyl, N-lauroyl-L-glutamic acid 2-octyldodecyl ester, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, di-2-ethylhexyl succinate, ethyl acetate, butyl acetate, amyl acetate, triethyl citrate, 2-ethylhexyl p-methoxycinnamate, tripropylene glycol dipivalate, and the like.

[0049] Specific examples of higher fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, undecylenic acid, tall acid, isostearic acid, linoleic acid, linolenic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).

[0050] The oil-based component may also be an oil-based thickener or oil gelling agent. Examples of oil-based thickeners include dextrin fatty acid esters, such as dextrin palmitate.

[0051] The aqueous component is not particularly limited as long as it is an aqueous component that is commonly used in external compositions such as cosmetics, quasi-drugs, etc. The aqueous component may include water, water-soluble alcohols, aqueous thickeners, moisturizers, chelating agents, preservatives, pigments, salts, etc.

[0052] The water that can be used may be purified water, ion-exchanged water, tap water, etc. The content of water in this embodiment may be preferably 5% by mass or more and 30% by mass or less, more preferably 7% by mass or more and 20% by mass or less, based on the total amount of the water-in-oil composition.

[0053] Examples of water-soluble alcohols include lower alcohols, polyhydric alcohols, polyhydric alcohol polymers, alcohol alkyl ethers, alcohol ether esters, glycerin monoalkyl ethers, sugar alcohols, monosaccharides, oligosaccharides, polysaccharides, and derivatives thereof.

[0054] Examples of the lower alcohol include ethanol, propanol, isopropanol, isobutyl alcohol, and t-butyl alcohol.

[0055] Examples of polyhydric alcohols include dihydric alcohols (e.g., dipropylene glycol, 1,3-butylene glycol, ethylene glycol, trimethylene glycol, 1,2-butylene glycol, tetramethylene glycol, 2,3-butylene glycol, pentamethylene glycol, 2-butene-1,4-diol, hexylene glycol, and octylene glycol), trihydric alcohols (e.g., glycerin and trimethylolpropane), tetrahydric alcohols (e.g., pentaerythritol such as diglycerin and 1,2,6-hexanetriol), pentahydric alcohols (e.g., xylitol and triglycerin), and hexahydric alcohols (e.g., sorbitol and mannitol).

[0056] Examples of thickeners include plant-based polymers (e.g., gum arabic, tragacanth gum, galactan, guar gum, carrageenan, etc.), microbial polymers (e.g., xanthan gum, dextran, succinoglycan, pullulan, etc.), animal-based polymers (e.g., collagen, casein, albumin, gelatin, etc.), starch-based polymers (e.g., carboxymethyl starch, methylhydroxypropyl starch, etc.), alginic acid-based polymers (e.g., sodium alginate, propylene glycol alginate, etc.), etc. Synthetic crosspolymers such as dimethylacrylamide / sodium acryloyldimethyltaurate crosspolymer may also be used.

[0057] The surfactant may be a cationic surfactant, anionic surfactant, nonionic surfactant, amphoteric surfactant, etc. Among these, it is preferable to use a nonionic surfactant. The surfactant component acts as an emulsifier and can improve the stability of the water-in-oil emulsion.

[0058] The nonionic surfactant is not particularly limited as long as it is a nonionic surfactant commonly used in compositions for application to skin. Specific examples of the nonionic surfactant include polyoxyethylene hydrogenated castor oils such as PEG-40 hydrogenated castor oil, PEG-60 hydrogenated castor oil, and PEG-100 hydrogenated castor oil; polyoxyethylene-methylpolysiloxane copolymers such as PEG-3 dimethicone, PEG-9 dimethicone, and PEG-10 dimethicone; branched polyoxyethylene-methylpolysiloxane copolymers such as PEG-9 polydimethylsiloxyethyl dimethicone; polyglyceryl-2 diisostearate, polytriisostearate, and the like. Examples include polyglycerol fatty acid esters such as diglyceryl-2; monoglycerol fatty acid esters such as glyceryl stearate and glyceryl oleate; polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monooleate and polyoxyethylene sorbitan monostearate; sorbitan fatty acid esters such as sorbitan sesquioleate, sorbitan sesquiisostearate, sorbitan isostearate, and sorbitan palmitate; and self-emulsifying propylene glycol stearate.

[0059] The organically modified clay mineral may be 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 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 (benzyldimethylstearylammonium 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 (distearyldimethylammonium 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 distearylammonium hectorite is more preferred. The content of the organically modified clay mineral may be preferably 0.1% by mass or more and 2% by mass or less based on the total amount of the water-in-oil composition.

[0060] The UV scattering agent is an inorganic powder, and specific examples 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 UV scattering agent may also be a composite powder in which particles other than titanium oxide are coated with titanium oxide. The average particle size of the UV scattering agent may be 10 nm or more and 100 nm or less. The content of the UV scattering agent may be preferably 5% by mass or more and 30% by mass or less, more preferably 10% by mass or more and 25% by mass or less, based on the total amount of the water-in-oil composition.

[0061] <Application> The use of the water-in-oil composition of this embodiment is not particularly limited, but the composition is preferably used as a composition for application to the skin, particularly as a cosmetic composition. The water-in-oil composition of this embodiment is also preferably used as a cosmetic composition having ultraviolet absorbing properties. For example, it may be a sunscreen composition, or a cosmetic with enhanced ultraviolet absorbing properties, such as a foundation, base makeup, or other basic cosmetic, or a makeup cosmetic.

[0062] According to this embodiment, it is possible to provide a sunscreen composition that exhibits a high ultraviolet protection effect, since it is possible to incorporate a higher content of ultraviolet absorber. [Example]

[0063] The components shown in Table 1 were mixed by a conventional method to produce compositions of Examples 1 to 6 and Comparative Examples 1 to 5. More specifically, the oil-based components were first mixed using a homomixer, and then the powder was added and dispersed. The aqueous components, which had been mixed in advance, were then added and mixed to obtain compositions. The resulting compositions were evaluated for usability and redispersibility (homogenization properties). Table 1 shows the evaluation results for Examples 1 to 6 and Comparative Examples 1 to 5.

[0064] <Evaluation of usability> Ten subjects were asked to rate the oiliness, smoothness, and squeaky feeling of each composition when applied to their arms on a 5-point scale (1 to 5 points) using the following criteria, and the average score was used to make a judgment. (1) Oiliness during application A: Average score 4.0 or higher B: Average score 3.0 or more and less than 4.0 C: Average score below 3.0

[0065] (2) Smooth feeling after application A: Average score 4.0 or higher B: Average score 3.0 or more and less than 4.0 C: Average score below 3.0

[0066] (3) Squeaky feeling after application A: Average score 4.0 or higher B: Average score 3.0 or more and less than 4.0 C: Average score below 3.0

[0067] <Evaluation of redispersibility> 30 g of the prepared composition was placed in a 40 mL container, the lid was placed on the container, and the container was shaken by hand, mainly up and down, while observing (redispersing). The ease of redispersion was evaluated based on the number of shakes required until the composition was visually recognized as being uniformly redispersed. A: Shake 3 times or less B: Shake 4 to 10 times C: Shaking count 11 or more times

[0068] [Table 1]

[0069] The percentages in Table 1 are mass %. The particle size of the cornstarch (hydrophilic powder) was 3 to 20 μm, and the particle size of the dimethicone-treated silica (hydrophobic silica powder) was 2 to 8 μm.

[0070] As shown in Table 1, the water-in-oil compositions (Examples 1 to 6) containing (a) an ultraviolet absorber having a silicone skeleton, (b) a volatile acyclic silicone oil, (c) 5% by mass or less of a cyclic silicone, (d) a hydrophobic silica powder, and (e) a hydrophilic powder were found to have excellent usability and homogenization properties.

[0071] Table 2 shows Formulation Example 1 (sunscreen agent) of the water-in-oil composition according to this embodiment. Formulation Example 1 can also be prepared in the same manner as Example 1 and the like.

[0072] [Table 2]

[0073] This application claims priority based on Patent Application No. 2021-033824, filed with the Japan Patent Office on March 3, 2021, the entire contents of which are incorporated herein by reference.

Claims

1. (a) an ultraviolet absorber having a silicone skeleton and a number average molecular weight of 2000 or more; (b) a volatile acyclic silicone oil; (c) 5% by mass or less of cyclic silicone; (d) hydrophobic silica powder, and (e) containing a hydrophilic powder; A water-in-oil composition, wherein the mass ratio of the content of the (d) hydrophobic silica powder to the content of the (e) hydrophilic powder is 1:0.5 to 1:

15.

2. A water-in-oil composition as described in claim 1, wherein the average particle size of the (d) hydrophobic silica powder is 1 μm or more.

3. A water-in-oil composition described in any one of claims 1 to 2, wherein the content of (d) hydrophobic silica powder is 0.1 mass% or more and 10 mass% or less relative to the total amount of the water-in-oil composition.

4. A water-in-oil composition described in any one of claims 1 to 3, wherein the (e) hydrophilic powder comprises at least one type of powder selected from the group consisting of silica, starch, and cellulose.

5. A water-in-oil composition described in any one of claims 1 to 4, having a viscosity of 300 mPa·s to 10,000 mPa·s.

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