Water-in-oil emulsified composition

Abstract

A water-in-oil emulsion composition comprising (A) a dibenzoylmethane derivative and (B) a metal oxide powder hydrophobically treated with a non-silicone substance, and substantially free of aluminum.

Description

Technical Field

[0001] This invention relates to a water-in-oil emulsion composition. Background Technology

[0002] As oil-in-water emulsion compositions for cosmetics and the like, compositions with UV protection capabilities are known. In these compositions, metal oxide powder with a hydrophobic surface treatment is typically added as a UV scattering agent. From the viewpoint of improving the dispersibility of the UV scattering agent, and thus improving the UV protection capability of the composition, hydrophobic treatment agents containing silicone substances are often used (e.g., Patent Document 1).

[0003] However, in recent years, considering the need to achieve sustainable development goals, silicone substances have been identified as having an environmental burden, and their use has been restricted or avoided. The use of non-silicone substances as hydrophobic treatment agents is also being explored.

[0004] Furthermore, various discussions have been conducted regarding ultraviolet absorbers, focusing on components that can enhance the ultraviolet protection capability of water-in-oil emulsion compositions. Benzoylmethane derivatives are known to be ultraviolet absorbers with high ultraviolet protection capability, particularly at long wavelengths (e.g., Patent Document 2).

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2021-167286 Patent Document 2: Japanese Patent Application Publication No. 2014-139228 Summary of the Invention The problem that the invention aims to solve Based on the above background, formulations combining metal oxide powder treated with non-silicone hydrophobic agents with dibenzoylmethane derivatives can be considered. However, it has been found that some combinations of metal oxide powder treated with non-silicone hydrophobic agents and dibenzoylmethane derivatives can cause discoloration. When discolored compositions are applied to a surface, they impair the original color of the surface, which is therefore disadvantageous.

[0006] In view of the above problems, one aspect of the present invention is to provide a water-in-oil emulsion composition with ultraviolet protection capability, wherein the components are not prone to discoloration while reducing environmental impact.

[0007] Solution for solving the problem One aspect of the present invention for solving the above-mentioned problems is a water-in-oil emulsion composition containing (A) a dibenzoylmethane derivative and (B) a metal oxide powder hydrophobically treated with a non-silicone substance, and substantially free of aluminum.

[0008] The effects of the invention According to one aspect of the present invention, an oil-in-water emulsion composition with ultraviolet protection capability can be provided, the components of which are less prone to discoloration while reducing environmental impact. Detailed Implementation

[0009] <Water-in-oil emulsion composition> One embodiment of the present invention is a water-in-oil (W / O) emulsion composition containing (A) a dibenzoylmethane derivative and (B) a metal oxide powder hydrophobically treated with a non-silicone substance, and substantially free of aluminum.

[0010] The use of the water-in-oil composition of this embodiment is not particularly limited, but it is preferably used in cosmetics, quasi-pharmaceuticals, personal care products, and other fields. Furthermore, the water-in-oil composition of this embodiment is preferred as a topical agent or skin application agent, especially as a cosmetic. More specifically, it can be used in sunscreens (sunscreen creams) for protection against ultraviolet rays, or in cosmetics with enhanced ultraviolet protection functions, such as basic cosmetics like foundation, color cosmetics, etc. Furthermore, the water-in-oil emulsion composition of this embodiment can be solid or semi-solid. It can also be provided in a gel, jelly, or cream form.

[0011] <UV absorber> <<(A) Benzoylmethane Derivatives>> Benzoylmethane derivatives are ultraviolet absorbers that exhibit high UV protection capabilities, and even small amounts can provide UV protection. Benzoylmethane derivatives are particularly effective in the long wavelength region, specifically above 300 nm and below 400 nm, where they demonstrate high UV absorption.

[0012] Specific examples of dibenzoylmethane derivatives include: tert-butylmethoxydibenzoylmethane (i.e., 4-tert-butyl-4'-methoxydibenzoylmethane), 2-methyldibenzoylmethane, 4-methyldibenzoylmethane, 4-isopropyldibenzoylmethane, 4-tert-butyldibenzoylmethane, 2,4-dimethyldibenzoylmethane, 2,5-dimethyldibenzoylmethane, 4,4'-diisopropyldibenzoylmethane, 4,4'-dimethoxydibenzoylmethane, 2 The following are examples of UV protection formulations: methyl-5-isopropyl-4'-methoxydibenzoylmethane, 2-methyl-5-tert-butyl-4'-methoxydibenzoylmethane, 2,4-dimethyl-4'-methoxydibenzoylmethane, 2,6-dimethyl-4-tert-butyl-4'-methoxydibenzoylmethane, 1-(4-tert-butylphenyl)-3-(2-hydroxyphenyl)propane-1,3-dione, and 1-(4-methoxy-1-benzofuran-5-yl)-3-phenylpropane-1,3-dione. Among these, tert-butylmethoxydibenzoylmethane is preferred because it provides exceptionally high UV protection even in small quantities.

[0013] Relative to the total amount of the water-in-oil emulsion composition, the content of (A) dibenzoylmethane derivative is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 8% by mass or less, and even more preferably 1% by mass or more and 5% by mass or less. When the content of dibenzoylmethane derivative is 0.1% by mass or more, the UV protection capability can be improved, especially the UV protection capability at long wavelengths. In addition, when the content of dibenzoylmethane derivative is 10% by mass or less, a balanced UV protection capability can be obtained throughout the entire UV wavelength range. At the same time, it also avoids excessive amounts of polar oil, thereby suppressing the degradation of the property stability of the water-in-oil emulsion composition.

[0014] <<UV absorbers other than dibenzoylmethane derivatives>> Furthermore, the water-in-oil emulsion composition of this embodiment may also contain ultraviolet absorbers other than benzoylmethane derivatives. Examples of ultraviolet absorbers other than benzoylmethane derivatives include: β,β-diphenylacrylate derivatives, salicylic acid derivatives, cinnamic acid derivatives, benzoic acid derivatives, benzophenone derivatives, benzyl camphor derivatives, phenylbenzimidazole derivatives, triazine derivatives, phenylbenzotriazole derivatives, anthranilic acid derivatives, imidazoline derivatives, benzylmalonate derivatives, and 4,4-diarylbutadiene derivatives.

[0015] Examples of β,β-diphenylacrylate derivatives include octocrylene. Examples of salicylic acid derivatives include ethylhexyl salicylate (ethylhexyl salicylate / octyl salicylate), homosalyl salicylate, dipropylene glycol salicylate, and TEA salicylate. Ethylhexyl salicylate is preferred. Examples of cinnamic acid derivatives include ethylhexyl methoxycinnamate (octyl methoxycinnamate), isopropyl methoxycinnamate, isoamyl methoxycinnamate, cinnoxalate, DEA methoxycinnamate, diisopropyl methyl cinnamate, glyceryl-ethylhexanoate-dimethoxycinnamate, and di-(2-ethylhexyl)-4'-methoxybenzylmalonate. Ethylhexyl methoxycinnamate is preferred.

[0016] Examples of benzoic acid derivatives include ethyl para-aminobenzoic acid (PABA), ethyl-dihydroxypropyl PABA, ethylhexyl-dimethyl PABA, glycerol PABA, PEG-25-PABA, and hexyl diethylaminohydroxybenzoylbenzoate. Examples of benzophenone derivatives include benzophenone-1, benzophenone-2, benzophenone-3 or oxybenzophenone, benzophenone-4, benzophenone-5, benzophenone-6, benzophenone-8, benzophenone-9, and benzophenone-12. Examples of benzylidene camphor derivatives include 3-benzylidene camphor, 4-methylbenzylidene camphor, benzylidene camphor sulfonic acid, methyl camphor benzalkonium sulfate, terephthalamide dicamphor sulfonic acid, and polyacrylamide methylbenzylidene camphor. Examples of phenylbenzimidazole derivatives include phenylbenzimidazole sulfonic acid and disodium phenyl dibenzimidazole tetrasulfonate. Examples of triazine derivatives include anisotriazine (bis-ethylhexyloxyphenol methoxyphenyl triazine), ethylhexyl triazine ketone, diethylhexylbutyramide triazine ketone, and 2,4,6-tris(diisobutyl-4'-aminobenzylmalonate)-s-triazine. Examples of phenylbenzotriazole derivatives include cresoltrazolium trisiloxane and methylenebis(benzotriazolyltetramethylbutylphenol). Examples of anthranilic acid derivatives include menthyl anthranilate. Examples of imidazoline derivatives include 2-ethylhexyl ethylhexyl dimethoxybenzyl dioxoimidazolidine propionate. Examples of benzylmalonate derivatives include polyorganosiloxanes having benzylmalonate functional groups. Examples of 4,4-diarylbutadiene derivatives include 1,1-dicarboxy(2,2'-dimethylpropyl)-4,4-diphenylbutadiene.

[0017] The ultraviolet absorbers other than the aforementioned dibenzoylmethane derivatives can be used alone or in combination of two or more. Preferably, the combination of a dibenzoylmethane derivative with octocrylene and ethylhexyl salicylate, or the combination of a dibenzoylmethane derivative with ethylhexyl methoxycinnamate, is used. These combinations broaden the wavelength range in which the ultraviolet absorbers exert their ultraviolet absorption capabilities compared to using only a dibenzoylmethane derivative.

[0018] The content of the dibenzoylmethane derivative is preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 40% by mass or less, relative to the total amount of ultraviolet absorber in the water-in-oil emulsion composition. Within this range, the ultraviolet absorption capacity of the water-in-oil emulsion composition, particularly in the long wavelength region, can be improved, while a balanced ultraviolet absorption capacity can be obtained across the entire ultraviolet wavelength range.

[0019] <(B) Metal oxide powder that has undergone hydrophobic treatment with non-silicone materials> The water-in-oil emulsion composition of this embodiment further comprises a hydrophobically treated metal oxide powder. This hydrophobically treated metal oxide powder is a metal oxide powder whose surface has been treated with a hydrophobic agent and has a hydrophobic surface. Preferably, this hydrophobically treated metal oxide powder has ultraviolet protection capability, specifically, it has ultraviolet scattering function, i.e., it is an ultraviolet scattering agent. Furthermore, since a non-silicone substance (described in detail below) is used in the hydrophobic treatment, (B) a metal oxide powder hydrophobically treated with a non-silicone substance is formed.

[0020] <<Metal Oxide Powders>> The hydrophobically treated metal oxide powder included as a UV scattering agent in the water-in-oil emulsion composition can be in particulate form. In this case, the average primary particle size of the metal oxide powder is not particularly limited, but can be 5 nm or more, 10 nm or more, or 15 nm or more, or 200 nm or less, 100 nm or less, or 50 nm or less. Furthermore, the "average primary particle size" in this specification can be obtained, for example, as the diameter of the equivalent circle of the projected area of ​​the primary particles in an SEM image.

[0021] Specific examples of metal oxide powders include titanium dioxide, zinc oxide, cerium oxide, iron oxide, and tungsten oxide. These metal oxide powders can be used individually or in combination of two or more. Among them, titanium dioxide and zinc oxide are preferred due to their high ultraviolet scattering properties. Furthermore, titanium dioxide is more preferred because of its high scattering properties for ultraviolet light in the relatively low wavelength range, particularly for ultraviolet light above 280 nm and below 320 nm. In addition, titanium dioxide, when combined with the aforementioned dibenzoylmethane derivatives, can impart ultraviolet protection capabilities to the water-in-oil emulsion composition over a wide wavelength range. Moreover, using titanium dioxide as the metal oxide powder can also improve the transparency of the resulting water-in-oil emulsion composition. The "transparency" of the water-in-oil emulsion composition refers to its transparency when applied to the coated surface. If the transparency is low, the coated surface will appear whitish, forming a so-called whitish appearance. This is particularly detrimental when the coated surface is skin, and is a phenomenon that users wish to avoid.

[0022] Furthermore, by making the water-in-oil emulsion composition substantially free of zinc oxide, the transparency of the water-in-oil emulsion composition can be improved. Additionally, in this specification, "substantially free" of the predetermined component means that unintentional aluminum inclusion is permitted during the raw material acquisition and / or manufacturing steps.

[0023] Surface Treatment The hydrophobically treated metal oxide powder, as described above, is a powder whose surface becomes hydrophobic through treatment with a hydrophobic agent. More specifically, a hydrophobic agent layer can be formed wholly or partially on the surface of the metal oxide powder particles. The hydrophobically treated metal oxide powder is mainly dispersed in the oil phase of the water-in-oil emulsion composition.

[0024] The hydrophobication treatment of the aforementioned metal oxide powder involves introducing hydrophobic groups onto the surface of the metal oxide powder particles, or forming a hydrophobic coating layer wholly or partially. Hydrophobication treatment can be performed using solvent-based wet methods, gas-phase methods, mechanochemical methods, etc.

[0025] In the above-mentioned hydrophobication treatment, non-silicone substances are used as hydrophobicating agents. Here, non-silicone substances refer to substances other than silicone substances. By using non-silicone substances as hydrophobicating agents, the silicone content in water-in-oil emulsion compositions can be reduced, resulting in compositions with reduced environmental impact and contributing to the achievement of sustainable development goals. Furthermore, in this specification, "silicone substances" refers to substances based on polyorganosiloxanes, and "silicone substances" include silicone oils, silicone surfactants, silicone rubber, silicone resins, etc.

[0026] Specific examples of hydrophobicating agents for non-silicone substances include alkyl phosphates, higher fatty acids, higher alcohols, higher fatty acid esters, dextrin fatty acid esters, metal soaps, and higher hydrocarbons. Among these, alkyl phosphates are preferred.

[0027] As an alkyl phosphate ester, monoalkyl phosphate is preferred. Furthermore, as an alkyl phosphate ester, higher alkyl phosphate esters are preferred, i.e., phosphate esters having an alkyl group having 6 or more carbon atoms, more preferably phosphate esters having a straight-chain or branched alkyl group having 8 or more and 30 or less carbon atoms, and even more preferably phosphate esters having a straight-chain alkyl group having 10 or more and 20 or less carbon atoms. In addition, the alkyl phosphate ester can be in the form of an ester or its salt (alkyl phosphate salt or alkyl phosphate ester salt). Specific examples of alkyl phosphate esters include cetyl phosphate (monocetyl phosphate ester), octyl phosphate ester, decyl phosphate ester (mondecyl phosphate ester), lauryl phosphate ester (dodecyl phosphate ester), myristyl phosphate ester, cetearyl phosphate ester, stearyl phosphate ester, etc., among which cetyl phosphate ester is particularly preferred. Metal oxide powders treated with a hydrophobicating agent containing cetyl phosphate ester exhibit high dispersibility in the composition, thus providing UV protection capabilities comparable to those using hydrophobicating agents composed of silicone substances. Furthermore, from the perspective of promoting the reduction of environmental impact, cetyl phosphate is also a preferred option.

[0028] Examples of higher fatty acids mentioned above include stearic acid, isostearic acid, and myristic acid. Examples of dextrin fatty acid esters include palmitic dextrin ester.

[0029] The above-mentioned hydrophobic treatment agents can be used alone or in combination of two or more.

[0030] In addition to the hydrophobic treatment described above, the surface of the metal oxide powder can also be treated with a hydrophilic treatment agent. In this case, the hydrophilic treatment agent and the hydrophobic treatment agent described above can be pre-mixed, and the mixed treatment agent can be used to treat the surface of the metal oxide powder. Alternatively, the surface of the metal oxide powder can first be treated with a hydrophilic treatment agent (hydrophilic treatment), followed by a treatment with a hydrophobic treatment agent (hydrophobic treatment). In addition, in this specification, the hydrophobic treatment agent and the hydrophilic treatment agent are sometimes collectively referred to as surface treatment agents.

[0031] The hydrophilicating agent can also be a non-silicone substance. Specifically, the hydrophilicating agent can be an inorganic silicate compound, a metal hydroxide, etc. Examples of inorganic silicates include untreated silica. Examples of metal hydroxides include magnesium hydroxide. Among these, untreated silica is preferred as the hydrophilicating agent. When untreated silica is used, the surface of the metal oxide powder particles can be more reliably coated, and the metal ions in the metal oxide powder are less likely to precipitate. Furthermore, since the dispersibility of the metal oxide powder can be further improved, the user experience of the water-in-oil emulsion composition can also be enhanced.

[0032] The above-mentioned hydrophilic treatment agents can be used alone or in combination of two or more.

[0033] Furthermore, when the surface treatment agent comprises both a hydrophobic agent and a hydrophilic agent, and an alkyl phosphate is used as the hydrophobic agent, untreated silica is preferably used as the hydrophilic agent. In this case, it is preferable to hydrophilically treat the surface of the metal oxide powder particles to form a silica coating, followed by a hydrophobic treatment to form an alkyl phosphate coating, thereby forming a double coating on the surface of the metal oxide powder particles. By pre-forming the silica coating, the alkyl phosphate coating can be formed more uniformly and reliably.

[0034] When a metal oxide powder that has undergone hydrophobic treatment with a non-silicone substance is included as an ultraviolet scattering agent, (B) the content of the metal oxide powder that has undergone hydrophobic treatment with a non-silicone substance is preferably 0.1% by mass or more and 30% by mass or less, more preferably 1% by mass or more and 25% by mass or less, even more preferably 3% by mass or more and 20% by mass or less, and particularly preferably 4% by mass or more and 13% by mass or less. When the content of the metal oxide powder that has undergone hydrophobic treatment with a non-silicone substance as an ultraviolet scattering agent is 0.1% by mass or more, the water-in-oil emulsion composition can exert sufficient ultraviolet protection function; when it is 30% by mass or less, the dispersion state of the ultraviolet scattering agent in the water-in-oil emulsion composition is better, and the transparency of the water-in-oil emulsion composition is also improved.

[0035] <About Aluminum> Furthermore, in this embodiment, the water-in-oil emulsion composition is substantially free of aluminum. Here, the term "aluminum" includes elemental aluminum and aluminum ions. Moreover, "the water-in-oil emulsion composition is substantially free of aluminum" means that aluminum is allowed to exist in some form in the water-in-oil emulsion composition due to unintentional contamination during the raw material acquisition and / or manufacturing steps. Furthermore, "the water-in-oil emulsion composition is substantially free of aluminum" means that the aluminum content (as elemental aluminum or aluminum ions) relative to the total amount of the water-in-oil emulsion composition is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.05% by mass or less. Particularly preferably, the aluminum content is 0% by mass relative to the total amount of the water-in-oil emulsion composition.

[0036] As described above, although the water-in-oil emulsion composition of this embodiment contains a benzoylmethane derivative as a UV absorber, the inventors have discovered that even a small amount of aluminum, for example, contained in a surface treatment agent that is a UV scattering agent, can cause discoloration that may affect the appearance of the final product (i.e., the water-in-oil emulsion composition). This is believed to be because the benzoylmethane derivative forms a complex with aluminum ions in the composition, resulting in a red color. If this water-in-oil emulsion composition is used as a skin application agent, this discoloration will alter the appearance of the skin, which is therefore detrimental to the user. In contrast, since the surface treatment agent of the metal oxide powder is substantially free of aluminum, discoloration (turning red) can be prevented.

[0037] In contrast, according to this embodiment, since the water-in-oil emulsion composition is substantially free of aluminum, it is possible to prevent discoloration caused by the interaction between the dibenzoylmethane derivative and aluminum.

[0038] Specifically, the surface treatment agent of the ultraviolet scattering agent does not substantially contain aluminum. Furthermore, the oil or aqueous phase of the water-in-oil emulsion composition does not substantially contain aluminum compounds or metallic aluminum. The meaning of "substantially does not contain" is as described above.

[0039] Furthermore, the color change described in this specification can be evaluated immediately after the final product (water-in-oil emulsion composition) is formulated, but it can be evaluated specifically by observing the color change after a specified time. More preferably, the evaluation is performed by observing the color change after a specified time at a high temperature. The specified time can refer to a period of several days to several weeks after product formulation. Furthermore, high temperature refers to a temperature exceeding room temperature (15°C to 25°C), which can be 30°C or higher, 40°C or higher, or 50°C or higher. For example, the color change evaluation of the water-in-oil emulsion composition of this embodiment can be evaluated by assessing whether it turns red after being stored at 50°C for 4 weeks after formulation.

[0040] <Organic Modified Clay Minerals> Organically modified clay minerals can act as co-emulsifiers, aiding in the emulsification of oil-based and water-based components. More specifically, by adding organically modified clay minerals, oil-based components can be effectively thickened or gelled, and the gelled state of the oil phase can be maintained over time, thereby stabilizing the dispersion of the aqueous phase. This allows for the long-term stable maintenance of the water-in-oil composition.

[0041] Organically modified clay minerals can be cationic modified clay minerals obtained by treating layered clay minerals such as bentonite, lithium montmorillonite, sphagnum molybdenum, montmorillonite, and magnesium aluminum silicate with quaternary ammonium salt-type cationic surfactants. Specific examples of organically modified clay minerals include distearate dimethylammonium sphagnum molybdenum (dimethyldistearate lithium saponite ammonium), dimethylalkylammonium sphagnum molybdenum, benzyl dimethylstearylammonium sphagnum molybdenum, and magnesium aluminum silicate treated with distearate dimethylammonium chloride. Among these, distearate dimethylammonium sphagnum molybdenum is preferred due to its high emulsifying properties. The above-mentioned organically modified clay minerals can be used alone or in combination of two or more.

[0042] The content of the organically modified clay mineral is preferably 0.05% by mass or more and 10% by mass or less relative to the total amount of the water-in-oil emulsion composition, more preferably 0.1% by mass or more and 5% by mass or less. When the content of the organically modified clay mineral is 0.05% by mass or more, the water-in-oil properties can be stabilized. In a composition with stable properties, the ultraviolet scattering agent is well dispersed, thus improving the ultraviolet protection capability. When titanium dioxide is used as a metal oxide powder, the ultraviolet protection capability in the low wavelength region can be improved. Furthermore, when the content of the organically modified clay mineral is 5% by mass or less, for example, when the water-in-oil emulsion composition is a skin application agent, a non-sticky and pleasant user experience can be obtained, and the spreadability on the skin becomes lighter, thereby improving usability.

[0043] <About silicone substances> As described above, no silicone substances are used in the hydrophobication treatment agent of the metal oxide powder that has been hydrophobically treated with non-silicone substances. In this embodiment, it is further preferred that the entire water-in-oil composition is also substantially free of silicone substances. "Silicone substances" refers to substances based on polyorganosiloxanes, including silicone oil, silicone rubber, silicone surfactants, silicone resins, etc. Since the entire water-in-oil composition is substantially free of silicone substances, silicone-free or low-silicone products can be provided, thereby reducing the environmental impact and contributing to a sustainable society. In addition, the meaning of "substantially free" is as described above. Furthermore, "the water-in-oil emulsion composition is substantially free of silicone substances" means that, relative to the total amount of the water-in-oil emulsion composition, the content of silicone substances is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.05% by mass or less. Further, it is particularly preferred that the content of silicone substances is 0% by mass relative to the total amount of the water-in-oil emulsion composition.

[0044] It is particularly preferred that the water-in-oil emulsion composition substantially does not contain silicone oil as an oily component. The meaning of "substantially does not contain" is as described above. Furthermore, "the water-in-oil emulsion composition substantially does not contain silicone oil" means that, relative to the total amount of the water-in-oil emulsion composition, the silicone oil content is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.05% by mass or less. Further, it is particularly preferred that the silicone oil content is 0% by mass relative to the total amount of the water-in-oil emulsion composition.

[0045] In addition, the preferred surfactant is substantially free of silicone surfactants, and the ultraviolet absorber is also preferably substantially free of silicone ultraviolet absorbers such as polysiloxane derivatives.

[0046] <Other Ingredients> In addition to the components described above, the water-in-oil emulsion composition of this embodiment may also contain other optional components. Examples of other components include: water as the main component of the aqueous phase, water-soluble alcohols, oily components other than UV absorbers, surfactants (including surfactant-like components), inorganic powders other than UV scattering agents, preservatives, stabilizers, pH adjusters, thickeners, pigments, antioxidants, anti-inflammatory agents, whitening agents, plant extracts, activators, blood circulation promoters, and anti-seborrheic agents. When the water-in-oil emulsion composition is a skin application agent, other components commonly used in cosmetics, quasi-pharmaceuticals, and other topical compositions may be used, and may be added in amounts that do not impair the effects of this embodiment.

[0047] <<Main Components of the Aqueous Phase>> As water, purified water, ion-exchanged water, tap water, etc. can be used. As water-soluble alcohols, examples include lower alcohols, polyols, polyol polymers, alkyl alcohol ethers, ether esters, monoalkyl glycerol ethers, sugar alcohols, and their derivatives.

[0048] Examples of lower alcohols include ethanol, propanol, isopropanol, isobutanol, and tert-butanol. Examples of polyols include diols (e.g., dipropylene glycol, 1,3-butanediol, ethylene glycol, trimethylenediol, 1,2-butanediol, tetramethylenediol, 2,3-butanediol, pentamethylenediol, 2-buten-1,4-diol, hexanediol, octanediol, etc.), triols (e.g., glycerin, trimethylolpropane, etc.), tetraols (e.g., pentaerythritol such as diglycerol, 1,2,6-hexanetriol, etc.), pentanols (e.g., xylitol, triglycerides, etc.), and hexaols (e.g., sorbitol, mannitol, etc.). Polyols also function as humectants.

[0049] <<Oily ingredients>> Examples of oily components include hydrocarbon oils, ester oils, higher fatty acids, higher alcohols, liquid fats, solid fats, and waxes. Hydrocarbon oils and ester oils are preferred, and a combination of both is more preferred. The content of the oily component relative to the total amount of the water-in-oil emulsion composition is preferably 10% by mass or more and 60% by mass or less, more preferably 20% by mass or more and 50% by mass or less.

[0050] Examples of hydrocarbon oils include isododecane, undecane, tridecane, isohexadecane, isoparaffins, liquid paraffin, ceresin, squalane, pterostilbene, paraffin wax, pure ceresin, squalene, petrolatum, and microcrystalline wax. Among these, isododecane, undecane, tridecane, and squalane are preferred.

[0051] Examples of ester oils include octyl palmitate, myristyl myristate, isononyl isononanoate, isopropyl myristate, cetyl 2-ethylhexanoate, octyl dodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, decyl oleate, hexyl decyl dimethyl octanoate, cetyl lactate, myristyl lactate, lanolin acetate, isocetyl stearate, isocetyl isostearate, 12-hydroxystearate cholesterol ester, and di-2- Ethylene hexanoate glycol ester, pentaerythritol fatty acid ester, N-alkyl glycol monoisostearate, neopentyl glycol didecanoate, diisostearate malate, glyceryl di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, pentaerythritol tetra-2-ethylhexanoate, glyceryl tri-2-ethylhexanoate (glyceryl triethylhexanoate), trimethylolpropane triisostearate, 2-ethylhexanoic acid Cetyl ester, 2-ethylhexyl palmitate, diethylhexyl naphthalenecarboxylate, alkyl benzoate (C12-15), cetearyl isononanoate, tri(caprylic / capric) glyceryl ester, butylene glycol (dicaprylic / capric) glyceryl ester, trimyristic acid glyceryl ester, tri-2-heptylundecanoate glyceryl ester, castor oil fatty acid methyl ester, oleic acid ester, cetearyl alcohol acetylated glyceryl ester, 2-heptylundecyl palmitate, diisobutyl adipic acid, 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 dineopentaate, etc. These ester oils can be used alone or in combination of two or more.

[0052] Examples of liquid fats include jojoba seed oil, avocado oil, camellia oil, turtle oil, macadamia nut oil, corn oil, mink oil, olive oil, rapeseed oil, egg yolk oil, sesame oil, peach kernel oil, wheat germ oil, camellia oil, castor oil, flaxseed oil, safflower oil, cottonseed oil, perilla oil, soybean oil, peanut oil, tea seed oil, torreya nut oil, rice bran oil, Chinese tung oil, Japanese tung oil, wheat germ oil, and triglycerides. Examples of solid fats include cocoa butter, coconut oil, hydrogenated coconut oil, palm oil, horse fat, beef tallow, mutton tallow, hydrogenated beef tallow, palm kernel oil, lard, beef bone fat, wood wax kernel oil, hydrogenated oil, beef hoof fat, wood wax, and hydrogenated castor oil.

[0053] The above-mentioned oily components can be used alone or in combination of two or more.

[0054] <<Surfactants>> Surfactants (including surfactant-like ingredients) act as emulsifiers, improving the stability of the formulation emulsion system. The surfactant content, relative to the total amount of the water-in-oil emulsion composition, is preferably 0.5% by mass or more and 8% by mass or less, more preferably 1% by mass or more and 5% by mass or less. The surfactant (including surfactant-like ingredients) can be cationic, anionic, nonionic, or amphoteric. Nonionic surfactants are preferred. Specific examples of nonionic surfactants include: sorbitan fatty acid esters such as sorbitan sesquiisostearate, sorbitan sesquioleate, sorbitan isostearate, and sorbitan palmitate; polyethylene glycol fatty acid esters such as PEG-8 diisostearate and PEG-10 diisostearate; polyglycerol fatty acid esters such as polyglycerol-2 diisostearate and polyglycerol-2 triisostearate; polyoxyethylene hydrogenated castor oil such as PEG-40 hydrogenated castor oil, PEG-60 hydrogenated castor oil, and PEG-100 hydrogenated castor oil; monoglyceride fatty acid esters such as glyceryl stearate and glyceryl oleate; and self-emulsifying propylene glycol stearate. In addition, higher fatty acids such as isostearic acid can be cited as surfactant-like ingredients. These surfactants can be used alone or in combination of two or more.

[0055] <<Inorganic Powders>> Inorganic powders other than ultraviolet scattering agents refer to inorganic powders that do not possess ultraviolet scattering capabilities. Examples include silica, talc, kaolin, mica, sericite, muscovite, phlogopite, synthetic mica, red mica, biotite, vermiculite, magnesium carbonate, calcium carbonate, barium silicate, calcium silicate, magnesium silicate, strontium silicate, tungstate metal salts, magnesium, zeolite, barium sulfate, calcined calcium sulfate (calcined gypsum), calcium phosphate, fluorapatite, hydroxyapatite, ceramic powder, metal soaps, and boron nitride. In addition, examples include inorganic white pigments (such as titanium dioxide, zinc oxide, etc.), inorganic red pigments (such as iron oxide (iron red), iron titanate, etc.), inorganic brown pigments (such as γ-iron oxide, etc.), inorganic yellow pigments (such as yellow iron oxide, loess, etc.), inorganic black pigments (such as black iron oxide, low-valent titanium dioxide, etc.), inorganic purple pigments (such as manganese violet, cobalt violet, etc.), inorganic green pigments (such as chromium oxide, chromium hydroxide, cobalt titanate, etc.), inorganic blue pigments (such as ultramarine, Prussian blue, etc.), pearlescent pigments (such as titanium dioxide coated with mica, titanium dioxide coated with bismuth oxychloride, titanium dioxide coated with talc, colored titanium dioxide coated with mica, bismuth oxychloride, fish scale foil, etc.), metallic powder pigments (such as copper powder, etc.), zirconium lake, barium lake and other organic pigments, natural pigments, etc. These inorganic powders can be untreated or have undergone surface treatment (hydrophobication treatment and / or hydrophilication treatment). In addition, these inorganic powders can be used alone or in combination of two or more.

[0056] Relative to the total amount of the water-in-oil emulsion composition, the content of inorganic powder, excluding the ultraviolet scattering agent, is preferably 1% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 20% by mass or less.

[0057] Example Experimental examples are shown below. The components shown in Table 1 were mixed according to standard methods to prepare composition samples for Examples 1 to 3 and Comparative Examples 1 to 3, and the results were evaluated. Table 1 also shows the evaluation results.

[0058] <Protective Capability> In this embodiment, the ultraviolet protection capability in the short wavelength region was mainly evaluated. On an S-plate (5cm × 5cm V-groove PMMA plate, SPFMASTER-PA01), at a concentration of 2 mg / cm²... 2 The sample of each composition obtained in each example was added dropwise, spread with a finger for 60 seconds, dried for 15 minutes, and then its absorbance (290 nm) was measured using a spectrophotometer (U-3500, manufactured by HITACHI). The absorbance (Abs) was calculated using the following formula, with the transmittance of the composition sample being T and the transmittance of the uncoated plate being To.

[0059] Abs = -log(T / To) Using Example 1 as a control, the composition samples were evaluated according to the following evaluation criteria.

[0060] A: The absorbance is greater than that of Example 1.

[0061] B: The absorbance is less than that of Example 1, and the difference between the absorbance of Example 1 and that of Example 1 is less than 0.15.

[0062] C: The absorbance is less than that of Example 1, and the difference between the absorbance of Example 1 and that of Example 1 is greater than 0.15 and less than 0.19.

[0063] D: The absorbance is less than that of Example 1, and the difference between the absorbance of Example 1 and that of Example 1 exceeds 0.19.

[0064] Transparency Each composition sample was filled into a plastic cuvette with a path length of 10 mm and a path width of 10 mm, and the transmittance in the 500 nm wavelength region was measured using a spectrophotometer (U-4100, manufactured by HITACHI). Using Example 1 as a control, the composition samples were evaluated according to the following evaluation criteria.

[0065] A: The transmittance is higher than that of Example 1.

[0066] B: The transmittance is the same as that of Example 1.

[0067] C: The transmittance is lower than that of Example 1.

[0068] <Color Change> Each composition sample was stored at 50°C for 4 weeks, and the color was visually observed and compared with the color before storage. Evaluation was conducted according to the following criteria.

[0069] A: No color change was observed.

[0070] B: Slight discoloration was observed.

[0071] C: Significant color change was observed.

[0072] Table 1 PEG-8 diisostearate: Manufactured by Emulsion Co., Ltd., Japan, Emalex 400DI-IS EX Dibutylpolydimethylsiloxane polyglycerol-3: Manufactured by Shin-Etsu Chemical Industry Co., Ltd., Silicone KF-6109 Polyglycerol-2 diisostearate: Manufactured by Matsumoto Fine Chemicals Co., Ltd., WOGEL-18DV Titanium dioxide / silica / cetyl phosphate: Titanium dioxide particles with an average primary particle size of 15 nm, whose surface is sequentially coated with silica and cetyl phosphate. Titanium dioxide / aluminum hydroxide / stearic acid: Titanium dioxide particles with an average primary particle size of 15 nm, whose surface is sequentially coated with aluminum hydroxide and stearic acid. Titanium dioxide / magnesium hydroxide / stearic acid: Titanium dioxide particles with an average primary particle size of 15 nm, whose surface is sequentially coated with magnesium hydroxide and stearic acid. Zinc oxide / palmitoyl dextrin ester: Zinc oxide particles coated with palmitoyl dextrin ester with an average primary particle size of 25 nm. In addition, the percentages in Table 1 are by mass.

[0073] As shown in Table 1, the composition samples (Examples 1-3) containing dibenzoylmethane derivatives and metal oxide powders hydrophobically treated with non-silicone substances, and substantially free of aluminum, not only did not exhibit discoloration but also displayed high UV protection capabilities. Furthermore, by using titanium dioxide surface-treated with silica and cetyl phosphate as the metal oxide powder hydrophobically treated with non-silicone substances (Examples 1 and 2), it was found that its UV protection capability was improved, and its transparency during coating was also excellent. In contrast, while the composition sample of Comparative Example 1 did not exhibit discoloration, its UV protection capability was lower because it did not contain dibenzoylmethane derivatives.

[0074] Similarly, the composition samples of Examples 4-6 were prepared, and the color change was evaluated.

[0075] Table 2 The results showed that the composition samples (Examples 4-6) containing dibenzoylmethane derivatives and metal oxide powders hydrophobically treated with silicone substances (more specifically cetyl phosphate) and substantially free of aluminum did not change color.

[0076] The present invention has been described above based on specific implementation methods and embodiments. However, these implementation methods and embodiments are merely examples, and the present invention is not limited to the above implementation methods and embodiments. Within the scope of the present invention, various changes, modifications, substitutions, deletions, additions, and combinations can be made.

[0077] This application claims priority based on Japanese Patent Application No. 2023-222429, filed on December 28, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A water-in-oil emulsion composition, comprising... (A) Benzoylmethane derivatives, and (B) Metal oxide powder treated with non-silicone materials to achieve hydrophobicity. It does not actually contain aluminum.

2. The water-in-oil emulsion composition according to claim 1, wherein the (A) dibenzoylmethane derivative comprises tert-butylmethoxydibenzoylmethane.

3. The water-in-oil emulsion composition according to claim 1, wherein the non-silicone substance comprises monoalkyl phosphate.

4. The water-in-oil emulsion composition according to claim 3, wherein the non-silicone substance comprises cetyl phosphate.

5. The water-in-oil emulsion composition according to claim 1 or 2, wherein the metal oxide powder is titanium oxide powder.

6. The water-in-oil emulsion composition according to claim 1 or 2 is substantially free of silicone oil.

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