JP7409789B2 - W/O type Pickering emulsion and cosmetics containing it - Google Patents

Description

The present invention relates to a W/O Pickering emulsion and a cosmetic containing the same.

Conventionally, so-called "secondary adhesion", in which cosmetics adhere to clothing, cups, etc. or come off due to physical contact such as rubbing with hands, has been a problem.

When secondary adhesion occurs, the makeup is ruined, making it necessary to frequently touch up the makeup. Additionally, there is the problem that when cosmetics adhere to clothing, it is difficult to remove them, which is a problem for many cosmetics users.

As a method of designing cosmetics to prevent secondary adhesion, a method is known that includes a polymer emulsion containing a film-forming agent containing a crosslinkable polymer containing a reactive silyl group (Patent Documents 1 and 2).

Japanese Patent Application Publication No. 2002-327019 Japanese Patent Application Publication No. 2003-20314

However, even with the method using such a film forming agent, secondary adhesion could not be sufficiently prevented.

The cause of secondary adhesion is that due to the highly adhesive nature of the cosmetic film, part of the cosmetic film is peeled off when force is applied to the surface (air interface) of the cosmetic film.

Therefore, as a means to reduce secondary adhesion, it is possible to reduce the adhesion of the entire cosmetic film, but in this case, the adhesion to the skin also decreases, and as a result, secondary adhesion may occur.

Therefore, an object of the present invention is to provide a technology for designing cosmetics with low secondary adhesion.

As a result of intensive research, the present inventors have found that an emulsion (Pickering emulsion) containing a specific oil agent at a specific blending ratio and emulsified with powder has excellent adhesion to the skin and has excellent secondary adhesion. The present invention was completed based on the discovery that the

That is, the present invention that solves the above problems,
This is a W/O Pickering emulsion that includes an aqueous phase, an oil phase, and a hydrophobized powder, and contains 40% by mass or more of a volatile oil based on the total amount of the oil contained in the oil phase.
The Pickering emulsion of the present invention has an extremely high secondary adhesion prevention effect.

In a preferred embodiment of the present invention, the content of the aqueous phase is 5% by mass or more based on the total amount of the W/O Pickering emulsion.
The W/O Pickering emulsion of the present invention in which the content of the aqueous phase is at least a specific amount has an extremely high secondary adhesion prevention effect.

In a preferred embodiment of the present invention, the hydrophobized powder has an M value of 10 or more.
By using a hydrophobized powder whose M value is greater than or equal to the above value, a higher secondary adhesion prevention effect can be obtained.

In a preferred embodiment of the present invention, the primary particle diameter of the hydrophobized powder is 200 nm or less.

In a preferred embodiment of the present invention, the hydrophobized powder is a powder coated with an acrylic resin and/or an organosilicon compound.

In a preferred embodiment of the present invention, the volatile oil agent is a hydrocarbon oil and/or a volatile silicone oil.

Moreover, the present invention which solves the above-mentioned problem is a cosmetic containing the above-mentioned W/O type Pickering emulsion.

In a preferred embodiment of the present invention, the cosmetic is a foundation or a sunscreen.

Furthermore, the present invention for solving the above problems includes:
preparing an aqueous phase;
comprising a step of preparing an oil phase;
The oil phase includes an oil agent and a hydrophobized powder, and the oil agent includes a volatile oil agent in an amount of 40 mass or more based on the total amount of the oil agent,
A method for producing a W/O Pickering emulsion, comprising a step of mixing the aqueous phase and the oil phase to prepare an emulsion.

Further, the present inventors conducted further research on the above-mentioned Pickering emulsion or the cosmetic film obtained by applying cosmetics, and found that the cosmetic film has excellent adhesion to the skin and low secondary adhesion. It was discovered that after the internal emulsion droplets volatilize, the membrane has a porous structure with hollow spaces surrounded by fine particles remaining intact. That is, by observing the structure of the cosmetic film, it is possible to identify the cosmetic film having the above properties.

That is, the present invention that solves the above problems,
A method for evaluating a cosmetic film, the method comprising:
The process of observing the surface or cross section of a cosmetic film obtained by applying a cosmetic containing a W/O Pickering emulsion and the process of observing the secondary adhesion suppressing effect when a porous structure is observed in the cosmetic film. This is a method for evaluating a cosmetic film, comprising a step of evaluating the cosmetic film to have the following characteristics.

The W/O Pickering emulsion of the present invention and cosmetics containing the same have extremely high secondary adhesion suppressing effects. Moreover, according to the cosmetic film evaluation method of the present invention, it is possible to identify cosmetics that are highly effective in suppressing secondary adhesion.

This is a photograph substituted for a drawing showing the results of a secondary adhesion test. These are SEM images of the cosmetic film surfaces of Examples and Comparative Examples. It is a CT image of a cross section of the cosmetic film of Example. It is a graph showing the amount of secondary adhesion versus drying time in Examples and Comparative Examples.

<1> W/O Pickering Emulsion The present invention is a W/O Pickering emulsion in which an aqueous phase and an oil phase are emulsified with hydrophobized powder. Each configuration will be explained in detail below.

(1) Oil phase component The Pickering emulsion of the present invention contains an oil agent as an oil phase component.
The content of the oil agent is preferably 10 to 80% by mass, more preferably 20 to 70% by mass, even more preferably 20 to 50% by mass, particularly preferably 20% by mass, based on the total amount of the Pickering emulsion. ~40% by mass.

The oil agent may include liquid oil, solid oil, wax, hydrocarbon oil, higher fatty acid, higher alcohol, ester oil, silicone oil, and the like.

Examples of liquid oils include avocado oil, camellia oil, turtle oil, macadamia nut oil, corn oil, mink oil, olive oil, rapeseed oil, egg yolk oil, sesame oil, persic oil, wheat germ oil, sasanqua oil, castor oil, and linseed oil. , safflower oil, cottonseed oil, eno oil, meadowfoam oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, chinensis oil, Japanese tung oil, jojoba oil, germ oil, triglycerin, glycerin trioctanoate, Examples include glycerin triisopalmitate.

Solid fats and oils include cacao butter, coconut oil, horse fat, hydrogenated coconut oil, palm oil, beef tallow, mutton tallow, hydrogenated beef tallow, palm kernel oil, pork fat, beef bone fat, Japanese oak kernel oil, hydrogenated fat, and beef leg fat. , Japanese oak oil, hydrogenated castor oil, etc.

Waxes include beeswax, candelilla wax, cotton wax, carnauba wax, bayberry wax, privet wax, spermaceti wax, montan wax, nut wax, lanolin, kapok wax, acetic acid lanolin, liquid lanolin, sugar cane wax, lanolin fatty acid isopropyl, hexyl laurate, reduced lanolin, Jojo Barrow, hard lanolin, shellac wax, POE lanolin alcohol ether, POE lanolin alcohol acetate, POE cholesterol ether, lanolin fatty acid polyethylene glycol, POE hydrogenated lanolin alcohol ether, and the like.

Examples of the hydrocarbon oil include liquid paraffin, ozokerite, pristane, paraffin, ceresin, squalene, petrolatum, microcrystalline wax, and the like.

Examples of higher fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, 12-hydroxystearic acid, undecylenic acid, and tolic acid.

Examples of higher alcohols include cetyl alcohol, stearyl alcohol, behenyl alcohol, batyl alcohol, myristyl alcohol, and cetostearyl alcohol.

Ester oils include isopropyl myristate, cetyl octoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctoate, cetyl lactate, myristyl lactate, Lanolin acetate, isocetyl stearate, isocetyl isostearate, sucrose stearate, sucrose oleate, cholesteryl 12-hydroxystearate, ethylene glycol di-2-ethylhexylate, dipentaerythritol fatty acid ester, N-alkyl glycol monoisostearate, dicaprin Neopentyl glycol acid, diisostearyl malate, glycerin di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexylate, trimethylolpropane triisostearate, pentaneerythritol tetra-2-ethylhexylate, tri-2- Glycerin ethylhexylate, trimethylolpropane triisostearate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, glycerin trimyristate, glycerin tri-2-heptylundecanoate, castor oil fatty acid methyl ester, oleic acid oil, seto Stearyl alcohol, acetoglyceride, 2-heptylundecyl palmitate, cetyl palmitate, diisobutyl adipate, N-lauroyl-L-glutamic acid-2-octyldodecyl ester, di-2-heptylundecyl adipate, ethyl laurate, Di-2-ethylhexyl sebatate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebatate, 2-ethylhexyl succinate, ethyl acetate, butyl acetate, amyl acetate, citric acid Examples include triethyl.

Examples of silicone oils include chain siloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, diphenyltrimethicone, diphenylsiloxyphenyltrimethicone, pentasiloxane, decamethylpolysiloxane, dodecamethylpolysiloxane, and tetrasiloxane. Examples include cyclic siloxanes such as methyltetrahydrogenpolysiloxane.

The Pickering emulsion of the present invention contains 40% by mass or more of a volatile oil agent based on the total amount of oil agent.
Preferable examples of the volatile oil agent include volatile silicone oil, volatile hydrocarbon oil, volatile ester oil, volatile natural animal and vegetable oil, and volatile fluorine oil. More preferred.

Volatile silicone oils include dimethylpolysiloxane, methyltrimethicone, tris(trimethylsilyl)methylsilane, tetrakis(trimethylsilyl)silane, hexacyclotrisiloxane, octamethyltetracyclosiloxane, cyclopentasiloxane, decamethylcyclopentasiloxane, and dodecamethyl. Examples include cyclohexasiloxane and tetradecamethylcycloheptasiloxane.

Examples of volatile hydrocarbon oils include decane, undecane, dodecane, tridecane, isooctane, isodecane, isododecane, isohexadecane, cyclodecane, and cyclododecane.

The Pickering emulsion of the present invention preferably contains both a volatile oil and a non-volatile oil.
The content of volatile oil based on the total amount of oil is preferably 42% by mass or more, more preferably 45% by mass or more.
Further, the upper limit of the volatile oil based on the total amount of oil is preferably 80% by mass or less, more preferably 65% by mass or less, still more preferably 60% by mass or less, particularly preferably 55% by mass or less, and most preferably 65% by mass or less. Preferably it is 50% by mass or less.

(2) Water phase component The content of water in the water phase of the Pickering emulsion of the present invention is preferably 5% by mass or more, more preferably 25% by mass or more, and still more preferably 35% by mass or more. , particularly preferably 40% by mass or more, most preferably 45% by mass or more.
By setting the water content within such a range, after the emulsified droplets in the cosmetic film are volatilized, the area occupied by the porous structure in the cosmetic film becomes larger, and the secondary adhesion effect is further enhanced.

Further, the water content is preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less, particularly preferably 60% by mass or less, and most preferably It is 50% by mass or less.
Further, the water content is preferably 1 to 60% by mass, more preferably 5 to 50% by mass or more, even more preferably 20 to 50% by mass, and particularly preferably 30 to 50% by mass. Most preferably, it is 40 to 50% by mass or more.

The content of water is preferably 0.05 to 2 parts by mass, more preferably 0.1 to 2 parts by mass, and even more preferably The amount is 0.4 to 2 parts by weight, particularly preferably 0.6 to 1.5 parts by weight, particularly preferably 0.8 to 1.2 parts by weight.
Further, the content of water is preferably 0.05 to 5 parts by mass, more preferably 0.5 to 4 parts by mass, and even more preferably 1 to 3 parts by mass, per 1 part by mass of the volatile oil agent. parts, particularly preferably 1.0 to 2.5 parts by mass,

The lower limit of the content of the total amount of the aqueous phase relative to the total amount of the Pickarig emulsion is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 30% by mass or more, and particularly preferably 40% by mass or more. It is at least 45% by mass, most preferably at least 45% by mass.
The upper limit is preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less, particularly preferably 60% by mass or less, and most preferably 55% by mass or less. It is.

Further, the content of the total amount of the aqueous phase relative to the total amount of the Pickering emulsion is preferably 5 to 70% by mass, more preferably 20 to 60% by mass, still more preferably 30 to 60% by mass, and particularly preferably is from 40 to 60% by weight, most preferably from 45 to 55% by weight.

The aqueous phase in the Pickering emulsion of the present invention can contain any components normally used in cosmetics without particular limitation, but preferably contains, for example, the following components.
Examples of polyols include polyethylene glycol, glycerin, 1,3-butylene glycol, erythritol, sorbitol, xylitol, maltitol, propylene glycol, dipropylene glycol, diglycerin, isoprene glycol, 1,2-pentanediol, 2,4-h Examples include xylene glycol, 1,2-hexanediol, 1,2-octanediol, and among them, glycerin, 1,3-butylene glycol, and sorbitol are preferred. The content of these is preferably 0.5 to 20% by weight, more preferably 3 to 10% by weight of the entire Pickering emulsion. Further, the content of these is preferably 3 to 15% by weight, more preferably 5 to 10% by weight of the aqueous phase.

The Pickering emulsion of the present invention may also contain a thickener. Thickeners include xanthan gum, gellan gum, guar gum, quince seed, carrageenan, galactan, gum arabic, pectin, mannan, starch, curdlan, methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, methylhydroxypropylcellulose, chondroitin sulfate, dermatan sulfate, Glycogen, heparan sulfate, hyaluronic acid, sodium hyaluronate, tragacanth gum, keratan sulfate, chondroitin, mucoitin sulfate, hydroxyethyl guar gum, carboxymethyl guar gum, dextran, keratosulfate, locust bean gum, succinoglucan, caronic acid, chitin, chitosan, Examples include carboxymethyl chitin, agar, polyvinyl alcohol, polyvinylpyrrolidone, carboxyvinyl polymer, sodium polyacrylate, polyethylene glycol, sodium acrylate grafted starch, stearoxyhydroxypropylmethylcellulose, bentonite, and the like. The content of these is preferably 0.05 to 5% by weight, more preferably 0.1 to 1% by weight of the entire Pickering emulsion. Further, the content of these is preferably 0.1 to 3% by mass, more preferably 0.3 to 1% by mass of the aqueous phase.

(3) Hydrophobized powder Hydrophobized powders include inorganic powders such as silica, titanium dioxide, tin oxide, clay minerals, aluminum oxide, nanoparticle precipitated calcium carbonate, coal, magnesium oxide, and magnesium trisilicate; In addition, organic powders such as resin particles such as ethyl cellulose, crystalline fatty alcohols and fatty acids, polystyrene, polymethyl methacrylate (PMMA), etc. can be used, and if necessary, the surfaces of these powders can be hydrophobized. You can use the
Preferably, partially hydrophobized powders whose surfaces are partially hydrophobized are used.

Examples of the hydrophobizing treatment include a method of treating the powder with a hydrophobizing agent such as an organosilicon compound, silicone, hydrocarbon oil, fatty acid, fatty acid amide, fatty acid ester, higher alcohol, or polyoxyalkylene compound.
Particularly preferably, the powder is treated using an organosilicon compound or silicone as a hydrophobizing agent.

Examples of organosilicon compounds include hexamethyldisilazane, monomethylsilane, dimethylsilane, trimethylsilane, trimethylethoxysilane, isobutyltrimethoxysilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, dimethylethoxysilane, dimethyldimethoxysilane, and diphenyldisilane. Examples include ethoxysilane, hexamethyldisiloxane, palmitylsilane, and the like. These can be used alone or in a mixture of two or more.

Examples of the silicone include dimethyl silicone, methylphenyl silicone, α-methylstyrene-modified silicone, chlorphenyl silicone, and fluorine-modified silicone.

The lower limit of the M value of the hydrophobized powder in the Pickering emulsion of the present invention is preferably 10 or more, more preferably 15 or more, and particularly preferably 20 or more.

The M value is a value that represents the degree of hydrophobicity of fine particles, and the higher the M value, the higher the hydrophobicity.The M value is the minimum value required to uniformly disperse the measurement sample in a mixed solution of water and methanol. It is expressed as a volume ratio of methanol and can be determined by the following method.

[How to calculate M value]
0.2 g of a measurement sample (hydrophobized fine powder particles) is added to 50 mL of water in a 250 mL beaker, and then methanol is gradually added dropwise from a burette. At this time, the solution in the beaker is constantly stirred with a magnetic stirrer, and the end point is defined as the point in time when the entire amount of the measurement sample is uniformly suspended in the solution. The volume percentage of methanol in the water/methanol mixed solution in the beaker at this end point is the M value.
The M value of the hydrophobized powder can be adjusted by its hydrophobization rate. The M value or the hydrophobization rate can be adjusted by appropriately setting the mixing ratio of the powder and the hydrophobizing agent and the treatment time.

The average primary particle size of the hydrophobized powder is preferably 200 nm or less, more preferably 100 nm or less, even more preferably 50 nm or less, more preferably 30 nm or less, particularly preferably 15 nm or less.
By setting the particle size of the hydrophobized powder within the above range, the emulsified particles can be controlled to be small, and the stability of the formulation is improved.

In the present invention, the average primary particle diameter is not particularly limited and refers to the diameter of primary particles measured by a method commonly used for particles, but specifically, from a transmission electron micrograph, It is determined as the arithmetic average of the long axis and short axis of the particle.

The content of the hydrophobized powder based on the total amount of the Pickering emulsion of the present invention is preferably 0.3 to 5% by mass, more preferably 0.4 to 4% by mass, even more preferably 0.5 to 3% by mass, Particularly preferably 0.7 to 2.5% by weight, most preferably 1 to 2% by weight.

The content of the hydrophobized powder is preferably 0.1 to 1 part by mass, more preferably 0.2 to 1 part by mass, and even more preferably 0.3 to 1 part by mass with respect to 10 parts by mass of the oil agent. , particularly preferably from 0.4 to 1 part by weight, most preferably from 0.5 to 0.8 part by weight.

The content of the hydrophobized powder is preferably 0.1 to 3 parts by mass, more preferably 0.1 to 1 part by mass, and even more preferably 0.1 to 0.5 parts by mass relative to 10 parts by mass of the water. Parts by weight, particularly preferably 0.2 to 0.3 parts by weight.

(4) Pickering emulsion The Pickering emulsion of the present invention is a water-in-oil type (W/O type) emulsion. In addition to the above-mentioned components, the Pickering emulsion of the present invention may contain optional components commonly used in cosmetics within a range that does not impair the effects of the invention. Such optional ingredients include, for example, fatty acid soaps (sodium laurate, sodium palmitate, etc.), potassium lauryl sulfate, anionic surfactants such as alkyl sulfate triethanolamine ether, stearyltrimethylammonium chloride, benzalkonium chloride, lauryl sulfate, etc. Cationic surfactants such as amine oxide, imidazoline amphoteric surfactants (2-cocoyl-2-imidazolinium hydroxide-1-carboxyethyloxy disodium salt, etc.), betaine surfactants (alkylbetaine, amide) betaine, sulfobetaine, etc.), amphoteric surfactants such as acylmethyltaurine, sorbitan fatty acid esters (sorbitan monostearate, sorbitan sesquioleate, etc.), glycerin fatty acids (glyceryl monostearate, etc.), propylene glycol fatty acid esters (propylene glycol monostearate, etc.), hydrogenated castor oil derivatives, glycerin alkyl ethers, POE sorbitan fatty acid esters (POE sorbitan monooleate, polyoxyethylene sorbitan monostearate, etc.), POE sorbitan fatty acid esters (POE-sorbitan, etc.) monolaurate, etc.), POE glycerin fatty acid esters (POE-glycerin monoisostearate, etc.), POE fatty acid esters (polyethylene glycol monooleate, POE distearate, etc.), POE alkyl ethers (POE2-octyldodecyl ether, etc.), POE alkylphenyl ethers (POE nonylphenyl ether, etc.), pluronic types, POE/POP alkyl ethers (POE/POP2-decyltetradecyl ether, etc.), silicone ethers such as triethoxycaprylylsilane, tetronics, POE castor oil/hydrogenated castor oil derivatives (POE castor oil, POE hydrogenated castor oil, etc.), sucrose fatty acid esters, nonionic surfactants such as alkyl glucosides, moisturizing ingredients such as sodium pyrrolidone carboxylate, lactic acid, sodium lactate, etc. , powders of mica, talc, kaolin, synthetic mica, calcium carbonate, magnesium carbonate, silicic anhydride (silica), aluminum hydroxide, iron oxide, titanium oxide, aluminum oxide, barium sulfate, etc., which may be surface-treated. Inorganic pigments such as cobalt oxide, ultramarine blue, navy blue, and zinc oxide, which may be surface-treated; Composite pigments such as iron oxide titanium dioxide sintered bodies, which may be surface-treated; Good, pearling agents such as mica titanium, fish phosphorus foil, bismuth oxychloride, etc., which may be made into lakes Red No. 202, Red No. 228, Red No. 226, Yellow No. 4, Blue No. 404, Yellow No. 5, Red Organic pigments such as No. 505, Red No. 230, Red No. 223, Orange No. 201, Red No. 213, Yellow No. 204, Yellow No. 203, Blue No. 1, Green No. 201, Purple No. 201, Red No. 204, polyethylene powder , organic powders such as polymethyl methacrylate, nylon powder, organopolysiloxane elastomer, lower alcohols such as ethanol and isopropanol, vitamin A or its derivatives, vitamin B6 hydrochloride, vitamin B6 tripalmitate, vitamin B6 dioctanoate, Vitamin B such as vitamin B2 or its derivatives, vitamin B12, vitamin B15 or its derivatives, α-tocopherol, β-tocopherol, γ-tocopherol, vitamin E such as vitamin E acetate, vitamin D, vitamin H, pantothenic acid , pantethine, vitamins such as pyrroloquinoline quinone, para-aminobenzoic acid, para-aminobenzoic acid monoglycerin ester, N,N-dipropoxypara-aminobenzoic acid ethyl ester, N,N-diethoxypara-aminobenzoic acid ethyl ester, N,N- Benzoic acid derivatives such as dimethyl para-aminobenzoic acid ethyl ester, N,N-dimethyl para-aminobenzoic acid butyl ester, N,N-dimethyl para-aminobenzoic acid ethyl ester, diethylaminohydroxybenzoyl hexyl benzoate; homomenthyl-N-acetylanthranilate, etc. Anthranilic acid derivatives such as salicylic acid and its sodium salt, amyl salicylate, menthyl salicylate, homomenthyl salicylate, octyl salicylate, phenyl salicylate, benzyl salicylate, p-isopropanol phenyl salicylate; octyl cinnamate, ethyl-4-isopropyl cinnamate mate, methyl-2,5-diisopropylcinnamate, ethyl-2,4-diisopropylcinnamate, methyl-2,4-diisopropylcinnamate, propyl-p-methoxycinnamate, isopropyl-p-methoxycinnamate, isoamyl- p-Methoxycinnamate, 2-ethylhexyl p-methoxycinnamate (ethylhexyl methoxycinnamate, octyl paramethoxycinnamate), 2-ethoxyethyl-p-methoxycinnamate (cinoxate), cyclohexyl-p-methoxycinnamate , ethyl-α-cyano-β-phenylcinnamate, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate (octocrylene), glyceryl mono-2-ethylhexanoyl-diparamethoxycinnamate, ferulic acid and its Cinnamic acid derivatives such as derivatives; 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2',4,4 '-Tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone (oxybenzone-3), 2-hydroxy-4-methoxy-4'-methylbenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonate, 4 - Benzophenone derivatives such as phenylbenzophenone, 2-ethylhexyl-4'-phenyl-benzophenone-2-carboxylate, 2-hydroxy-4-n-octoxybenzophenone, 4-hydroxy-3-carboxybenzophenone; 3-(4' -methylbenzylidene)-d,l-camphor, 3-benzylidene-d,l-camphor; 2-phenyl-5-methylbenzoxazole; 2,2'-hydroxy-5-methylphenylbenzotriazole; 2-(2 '-hydroxy-5'-t-octylphenyl)benzotriazole;2-(2'-hydroxy-5'-methylphenylbenzotriazole;dibenzalazine;dianisoylmethane; 5-(3,3-dimethyl-2-norbornylidene) -3-pentan-2-one; dibenzoylmethane derivatives such as 4-t-butylmethoxydibenzoylmethane; octyltriazone; urocanic acid derivatives such as urocanic acid and ethyl urocanate; 2-(2'-hydroxy-5 Hydantoin derivatives such as '-methylphenyl)benzotriazole, 1-(3,4-dimethoxyphenyl)-4,4-dimethyl-1,3-pentanedione, and 2-ethylhexyl dimethoxybenzylidene dioxoimidazolidine propionate; phenylbenz Preferred examples include UV absorbers such as imidasozole sulfonic acid, terephthalylidene dicanfursulfonic acid, drometrizole trisiloxane, methyl anthranilate, bisethylhexyloxyphenol methoxyphenyl triazine, rutin and its derivatives, oryzanol and its derivatives. can.

As mentioned above, although a surfactant may be used in the Pickering emulsion of the present invention, it is preferable to keep the content as low as possible. The content of the surfactant is preferably 5% by mass or less, more preferably 1% by mass or less, further preferably 0.1% by mass or less, particularly preferably 0% by mass.

The Pickering emulsion of the present invention is suitable for external use on the skin because of its high secondary adhesion inhibiting effect.
Among these, it is preferably used in cosmetics, such as sunscreens, makeup bases, and foundations. As the foundation, it is particularly preferable to use it as a liquid foundation.

The Pickering emulsion of the present invention can be produced by the following production method.
First, the method includes a step of preparing an aqueous phase containing the above-mentioned optional components as appropriate, and a step of preparing the above-mentioned oil phase.
The oil phase contains an oil agent and a hydrophobized powder, and the oil agent contains 40% by mass or more of a volatile oil agent based on the total amount of the oil agent.

Next, by mixing the aqueous phase and the oil phase, emulsification of the aqueous phase and oil phase by the hydrophobized powder occurs, and the W/O Pickering emulsion of the present invention is produced.

When the Pickering emulsion of the present invention and the cosmetic containing the same are stored in a container, the powder exists at the interface between the aqueous phase and the oil phase and maintains an emulsified state.

The present inventors have confirmed that when this is applied to the skin, after the emulsified droplets volatilize, hollow spaces surrounded by fine particles remain as they are, forming a porous structure.

From this knowledge, it is considered that the excellent secondary adhesion suppressing effect of the Pickering emulsion and cosmetics of the present invention is due to the porous structure after volatilization of emulsion droplets.

<2> Cosmetic film evaluation method The present invention is a cosmetic film evaluation method, and is an invention completed based on the above-mentioned knowledge.
The cosmetic film evaluation method of the present invention includes the step of observing the surface or cross section of a cosmetic film obtained by applying a cosmetic containing a W/O Pickering emulsion.
The surface of the cosmetic film can be observed using, for example, a microscope. As the microscope, an optical microscope, an electron microscope, etc. can be used, and it is preferable to use a scanning electron microscope (SEM).
Observation of the surface of the cosmetic film can be performed using, for example, an X-ray CT device.

Next, the cosmetic film evaluation method of the present invention includes a step of evaluating the cosmetic film as having a secondary adhesion suppressing effect when a porous structure is observed in the cosmetic film.
In this way, it is presumed that a cosmetic film with a porous structure can suppress secondary adhesion by preventing direct contact between the secondary adhesion destination such as clothing and the liquid component in the cosmetic film. Ru.
Furthermore, since a cosmetic film having a porous structure has high structural strength due to the porous structure, it is presumed that the cosmetic film is resistant to abrasion.

Preferably, in the evaluation method of the present invention, when the occupancy rate of the porous structure with respect to the thickness of the decorative film exceeds 50%, the cosmetic film with the occupancy rate of less than 50% has better secondary adhesion control. An evaluation step is provided to evaluate whether the cosmetic film has an effect.
The reference value of the occupancy rate in the evaluation is preferably 55%, more preferably 70%, even more preferably 75%, particularly preferably 80%, and most preferably 95%.
This evaluation step is based on the knowledge that the greater the occupancy of the porous structure relative to the thickness of the decorative film, the greater the secondary adhesion suppressing effect.

The occupancy rate can be derived by calculation.
First, the cosmetic film is observed, and if a porous structure is confirmed, the particle size of the porous structure is measured. The particle size of this porous structure can be assumed to be the particle size of water droplets in a W/O emulsion. When powder having an arbitrary particle size and emulsifying ability is adsorbed to this and piled up, it is possible to calculate the occupancy rate of the porous structure with respect to the thickness of the decorative film.

<Test Example 1> Preparation of emulsion The aqueous phase and oil phase shown in Table 1 below were prepared, and these were mixed and emulsified to produce a foundation.
Note that "powder" in Table 1 is a powder that does not have emulsifying ability, and "silylated silica" in the "emulsifier" column is "hydrophobicized powder" in this specification. In this test, silylated silyl having an average primary particle diameter of 12 nm and an M value of 10 or more was used.
Moreover, "W/O(P)" in Table 1 means a W/O type Pickering emulsion, and "W/O" means a W/O type emulsion that is not a Pickering emulsion.

<Test Example 2> Secondary Adhesion Evaluation Test For Example 1, Comparative Example 1, and Comparative Example 2, the following tests were conducted to evaluate secondary adhesion.
The foundation prepared in Test Example 1 was applied at 2 mg/cm ² to a 5 cm x 5 cm artificial leather.
After drying for 10 minutes, a 5 cm x 5 cm white cloth (100% cotton) was placed over the foundation applied to the artificial leather.
Furthermore, a 300 g weight was placed on top of it, and the white cloth was pulled out in that state.

The foundation adhering to the white cloth was visually confirmed. In addition, a white cloth was photographed, and the areas to which foundation had adhered and those to which foundation had not adhered were binarized to determine the area ratio. The results are shown in Table 1 and Figure 1.

From the results in Table 1 and FIG. 1, it is clear that the Pickering emulsion contains an aqueous phase, an oil phase, and a hydrophobized powder, and contains 40% by mass or more of a volatile oil based on the total amount of oil contained in the oil phase. It can be seen that Examples 1 to 5 have extremely low secondary adhesion.

On the other hand, Comparative Example 1, which emulsified with a silicone surfactant without using powder (equivalent to conventional liquid foundation), and Comparative Example 2, which did not contain water and used only an oil as a dispersion medium, were secondary. Adhesion was high.

Comparative Example 2, which did not contain water and used only an oil agent as a dispersion medium, had excellent adhesion to the skin and was easy to dry, but had high secondary adhesion. This result shows that the water-in-oil emulsion system is one of the factors that reduces secondary adhesion.

Furthermore, Comparative Example 3, in which the volatile oil was less than 40% by mass of the total amount of the oil, had high secondary adhesion.
From this result, it was found that containing at least 40% by mass or more of the volatile oil based on the total amount of the oil provides a composition with excellent secondary adhesion.

<Test Example 3> Observation of Film Structure Foundations were prepared according to the formulations shown in Table 2 below (Example 6, Comparative Example 4, Comparative Example 5).
The prepared foundation was applied onto artificial leather at a concentration of 0.2 mg/cm ² , and after drying for 30 minutes, the surface was observed using SEM.
Regarding the foundation of Example 2, cross-sectional observation was further performed using an X-ray CT device. The results are shown in FIGS. 2 and 3.

<Test Example 4> Change in secondary adhesion amount depending on drying time In the secondary adhesion evaluation test of Test Example 2, the drying time was varied from 1 minute, 3 minutes, 5 minutes, 10 minutes, and 15 minutes. The secondary adhesion properties of Example 6, Comparative Example 4, and Comparative Example 5 were evaluated. Note that each verification was performed with N=3, and the average value was calculated. The results are shown in Figure 4.

Example 6 was excellent in the effect of suppressing secondary adhesion to the skin, and Comparative Examples 4 and 5 could not confirm the effect of suppressing secondary adhesion. This result agrees well with the result of Test Example 2.
From FIGS. 2 and 3, it was confirmed that the cosmetic film obtained from the foundation of Example 6 had a porous structure with cavities of about 5 μm, which was presumably formed after the emulsion droplets evaporated. In the foundation using a surfactant (Comparative Example 4) and the foundation using an oil dispersion (Comparative Example 5), no porous structure could be confirmed, and agglomeration of powder was observed in some places.
In this way, the emulsified foundation that adopts the form of Pickering emulsion can form a cosmetic film with a porous structure, and has an excellent secondary adhesion suppressing effect due to the porous structure. confirmed.

Further, from the results shown in FIG. 3, the foundation of Example 6 had a high secondary adhesion suppressing effect regardless of the standing time. In particular, the results of the standing time of 1 minute, assuming a state where the foundation is not dry, showed that the amount of secondary adhesion was significantly suppressed compared to Comparative Examples 4 and 5.

<Test Example 4> Confirmation test for the influence of the amount of aqueous phase A foundation was prepared according to the formulations listed in Table 3 below.
For each foundation, the same test as in Test Example 4 was conducted to evaluate the amount of secondary adhesion. The results are shown in Table 3. Note that, unlike in Tables 1 and 2, a nonvolatile dimethicone was used as dimethicone in Table 3.

<Test Example 5> Simulation of porous structure occupancy rate in cosmetic film In Examples 7 to 12, 12 nm powder is adsorbed around 5 μm water droplets in W/O emulsion and the powder is piled up. The occupancy of the porous structure with respect to the thickness of was calculated. The results are shown in Table 3.

From the results in Table 3, it was shown that the higher the content of the aqueous phase or the content of water relative to the total amount of the Pickering emulsion, the more excellent the secondary adhesion suppressing effect was.
In particular, Examples 7, 8, and 9 in which the aqueous phase content is 30% by mass or more, or the water content is 25% by mass or more, have particularly excellent secondary adhesion suppressing effects.
Examples 7 and 12 had the best secondary adhesion suppressing effect, with a secondary adhesion rate of less than 6% at a drying time of 1 minute and a secondary adhesion rate of less than 1% at a drying time of 15 minutes. . This result showed that the Pickering emulsion of the present invention can form a cosmetic film having an excellent secondary adhesion suppressing effect even when the type of volatile oil is different.

In addition, in Examples 10 and 11, the secondary adhesion suppressing effect when the drying time is 15 minutes is inferior to that of Comparative Example 5, but when the drying time is 1 minute, the secondary adhesion suppressing effect is lower than that of the comparative example. Better than 5. From this result, Examples 10 and 11 have a superior secondary adhesion suppressing effect compared to the comparative example in the non-dry state after application, where secondary adhesion is most likely to occur. It can be said.

The present invention can be applied to the design of a membrane structure that has excellent adhesion and low secondary adhesion.

Claims (12)

Contains an aqueous phase, an oil phase, and a hydrophobized powder having a primary particle size of 200 nm or less and an M value of 10 or more, and contains 40% by mass of a volatile oil agent based on the total amount of oil agent contained in the oil phase. Contains not more than 80% by mass ,
A W/O Pickering emulsion, characterized in that the hydrophobized powder is a powder coated with an acrylic resin and/or an organosilicon compound. The W/O Pickering emulsion according to claim 1, wherein the content of the oil agent is 20 to 70% by mass based on the total amount of the W/O Pickering emulsion. The W/O Pickering emulsion according to claim 2 , wherein the W/O Pickering emulsion contains 40% by mass or more and 65% by mass or less of a volatile oil based on the total amount of the oil contained in the oil phase . Contains 40% by mass or more and 55% by mass or less of a volatile oil based on the total amount of oil contained in the entire oil phase, and the content of the oil is 20 to 50% by mass based on the total amount of the W/O Pickering emulsion. , W/O type Pickering emulsion according to any one of claims 1 to 3. The W/O Pickering emulsion according to any one of claims 1 to 4 , wherein the hydrophobized powder exists at the interface between the water phase and the oil phase and maintains an emulsified state. The W/O type Pickering emulsion according to any one of claims 1 to 5 , wherein the content of the total amount of the aqueous phase is 5% by mass or more with respect to the total amount of the W/O type Pickering emulsion. . The W/O Pickering emulsion according to any one of claims 1 to 6 , wherein the volatile oil agent is a hydrocarbon oil and/or a volatile silicone oil. A cosmetic comprising the W/O Pickering emulsion according to any one of claims 1 to 7 . The cosmetic according to claim 8 , which is a foundation or a sunscreen. The W/O type picker according to any one of claims 1 to 9, characterized in that after the internal emulsified droplets volatilize, a hollow space surrounded by fine particles remains intact, forming a porous structure. ring emulsion. preparing an aqueous phase;
comprising a step of preparing an oil phase;
The oil phase contains an oil agent and a hydrophobized powder having a primary particle size of 200 nm or less and an M value of 10 or more, and the oil phase contains 40% by mass or more and 80% by mass or less of the total amount of the oil agent. The hydrophobized powder is a powder coated with an acrylic resin and/or an organosilicon compound, and contains a volatile oil agent;
A method for producing a W/O Pickering emulsion, comprising a step of mixing the aqueous phase and the oil phase to prepare an emulsion. A method for evaluating a cosmetic film, the method comprising:
The process of observing the surface or cross section of a cosmetic film obtained by applying a cosmetic containing a W/O Pickering emulsion and the process of observing the secondary adhesion suppressing effect when a porous structure is observed in the cosmetic film. A method for evaluating a cosmetic film, comprising the step of evaluating the cosmetic film to be a cosmetic film.