JP7790867B2 - Oil-in-water emulsion cosmetics - Google Patents

Description

The present invention relates to an oil-in-water emulsion cosmetic containing hydrophobically treated silica-coated zinc oxide in the internal phase (oil phase).

Cosmetics designed to block ultraviolet rays in sunlight and protect the skin from the harmful effects of ultraviolet rays contain metal oxides such as titanium oxide and zinc oxide as UV scattering agents to protect against ultraviolet rays. For example, Patent Document 1 describes a sunscreen cosmetic that combines two types of zinc oxide powder manufactured using different methods, thereby providing excellent protection against ultraviolet A (UVA) rays and an inconspicuous application color.

On the other hand, as a cosmetic product that combines sunscreen cosmetics with whitening properties, Patent Document 2 describes a water-in-oil emulsion cosmetic product containing silica-coated zinc oxide and tranexamic acid or its salt. Furthermore, Patent Document 3 describes a water-in-oil emulsion sunscreen cosmetic product containing hydrophobically treated silica-coated zinc oxide particles and a specified amount of volatile hydrocarbon oil and volatile dimethicone.

In general, water-in-oil emulsion cosmetics contain UV absorbers in the oil phase, which provides strong sunscreen effects and excellent stability, but many are difficult to wash off easily with regular cleansers or soap. Furthermore, the high content of UV absorbers can cause a dry feeling, which can be a turn-off for some. On the other hand, oil-in-water emulsion cosmetics have the advantage of being relatively easy to wash off, causing less dryness, and leaving a fresh feeling after use.

Among oil-in-water emulsion cosmetics, those that emulsify a hydrophobized UV scattering agent can reduce stickiness and therefore achieve a more refreshing feel when used. For example, Patent Document 4 describes an oil-in-water emulsion cosmetic in which hydrophobized silica-coated zinc oxide is dispersed in the external phase (aqueous phase).

Japanese Patent Application Publication No. 11-302144 Patent No. 5792493 International Publication No. 2014/077189 Patent No. 6733549

Patent Document 4 describes an oil-in-water emulsion cosmetic in which hydrophobically treated silica-coated zinc oxide is dispersed in an aqueous phase. However, if a more refreshing feel, skincare-like feel, and post-application properties such as cosmetic longevity are desired, an oil-in-water emulsion cosmetic in which hydrophobically treated powder is contained in the oil phase and this oil phase is dispersed in the aqueous phase is preferable. This hydrophobically treated silica-coated zinc oxide has excellent dispersibility in cyclic silicones, and if the oil phase is cyclic silicone, the hydrophobically treated silica-coated zinc oxide can be stably trapped in the internal phase of the emulsion particles, preventing the elution of metal (zinc) ions, making it possible to incorporate it into the aqueous phase.

However, due to environmental regulations, the use of cyclic silicones is being avoided. Therefore, when dimethylpolysiloxane (dimethicone) was investigated as an alternative oil to cyclic silicones as a dispersant, it was found that poor dispersion of the powder in the internal phase caused aggregation and coalescence of emulsified particles, reducing dispersion ability and emulsion stability. In the case of oil-in-water emulsion cosmetics, in which hydrophobically treated powder is contained in the oil phase and this oil phase is dispersed in the water phase, if aggregation occurs due to reduced dispersion ability, the hydrophobically treated powder may escape from the internal phase or zinc ions may be eluted, significantly adversely affecting the stability of the formulation.

The present invention was developed in consideration of the above circumstances, and aims to provide an oil-in-water emulsion cosmetic that can improve emulsion stability without using cyclic silicones and has a high UV protection effect.

The oil-in-water emulsion cosmetic of the present invention comprises:
(A) a hydrophobized silica-coated zinc oxide having an outermost surface hydrophobized with a hydrophobizing agent and having a coating layer containing silica;
(B) a volatile acyclic silicone;
An oil-in-water emulsion cosmetic comprising:
(A) containing hydrophobically treated silica-coated zinc oxide in the internal phase;
(A) The content of silica relative to the total amount of hydrophobized silica-coated zinc oxide is 10 mass% or more, and the content of the hydrophobizing agent relative to the total amount of hydrophobized silica-coated zinc oxide is 9 mass% or more and less than 14 mass%.

The hydrophobic treatment agent is preferably dimethicone.

(A) The content of the hydrophobic treatment agent relative to the total amount of hydrophobic treated silica-coated zinc oxide is preferably 10 to 13 mass%.

(A) It is preferable that the cosmetic contains 8% by mass or more of hydrophobized silica-coated zinc oxide based on the total amount of the cosmetic.

(B) The volatile acyclic silicone is preferably a volatile linear silicone.

The volatile linear silicone is preferably octamethyltrisiloxane, decamethyltetrasiloxane, or dodecamethylpentasiloxane.

The oil-in-water emulsion cosmetic of the present invention may further contain (C) an organic acid or a salt thereof.

The oil-in-water emulsion cosmetic of the present invention comprises:
(A) a hydrophobized silica-coated zinc oxide having an outermost surface hydrophobized with a hydrophobizing agent and having a coating layer containing silica;
(B) a volatile acyclic silicone;
An oil-in-water emulsion cosmetic comprising:
(A) containing hydrophobically treated silica-coated zinc oxide in the internal phase;
The content of silica relative to the total amount of (A) hydrophobized silica-coated zinc oxide is 10% by mass or more, and the content of the hydrophobizing agent relative to the total amount of (A) hydrophobized silica-coated zinc oxide is 9% by mass or more and less than 14% by mass, so that the emulsion stability can be improved without using cyclic silicone, and a high ultraviolet protection effect can be achieved.

The present invention will be described in detail below.
The oil-in-water emulsion cosmetic of the present invention comprises:
(A) a hydrophobized silica-coated zinc oxide having an outermost surface hydrophobized with a hydrophobizing agent and having a coating layer containing silica;
(B) a volatile acyclic silicone;
An oil-in-water emulsion cosmetic comprising:
(A) containing hydrophobically treated silica-coated zinc oxide in the internal phase;
(A) The content of silica relative to the total amount of hydrophobized silica-coated zinc oxide is 10 mass% or more, and the content of the hydrophobizing agent relative to the total amount of hydrophobized silica-coated zinc oxide is 9 mass% or more and less than 14 mass%.
Each component will be described in detail below.
In this specification, POE is an abbreviation for polyoxyethylene, and PEG is an abbreviation for polyethylene glycol.

(A) Hydrophobized Silica-Coated Zinc Oxide (A) hydrophobized silica-coated zinc oxide is zinc oxide whose outermost surface has been hydrophobized with a hydrophobizing agent and has a coating layer containing silica. The oil-in-water emulsion cosmetic of the present invention is an oil-in-water emulsion cosmetic in which an oil phase (internal phase) is dispersed in an aqueous phase (external phase), and (A) hydrophobized silica-coated zinc oxide is contained in the internal phase. In this way, by forming an oil-in-water emulsion cosmetic in which (A) hydrophobized silica-coated zinc oxide is contained in the oil phase and this oil phase is dispersed in the aqueous phase, a more refreshing, skincare-like feel can be obtained.

The zinc oxide preferably has an average particle size of 0.01 to 0.1 μm, and more preferably 0.01 to 0.05 μm. Commercially available zinc oxide products include FINEX-25, FINEX-50, and FINEX-75 (all manufactured by Sakai Chemical Industry Co., Ltd.), ZnO350 (manufactured by Sumitomo Osaka Cement Co., Ltd.), ZINCOX SUPER-10, ZINCOX SUPER-20R, and ZINCOX SUPER-30 (all manufactured by Hakusui Chemical Industry Co., Ltd.), and Z-COTE (manufactured by Sun Smart).

Silica-coated zinc oxide can be obtained by forming a silica coating layer on the surface of the zinc oxide using a conventional method. Specifically, for example, silica-coated zinc oxide can be obtained by adding sodium silicate and neutralizing the zinc oxide in an aqueous solution while maintaining a high degree of dispersion using a sand grinder mill or the like, thereby uniformly coating the surfaces of the zinc oxide powder particles with silicic anhydride. Silica-coated zinc oxide can also be obtained by highly dispersing the zinc oxide in an organic solvent, then adding an alkoxysilane to uniformly coat the surfaces of the zinc oxide powder particles with silicic anhydride. Other manufacturing methods besides these are also possible, as long as the final product is coated with a certain amount of silica (silica content of 10% by mass or more of the total amount of hydrophobized silica-coated zinc oxide).

The silica content relative to the total amount of hydrophobized silica-coated zinc oxide is 10% by mass or more, more preferably 10 to 18% by mass, and even more preferably 10 to 15% by mass. By having a silica content of 10% by mass or more relative to the total amount of hydrophobized silica-coated zinc oxide, the zinc oxide can be more uniformly coated, thereby suppressing the outflow of zinc ions. Furthermore, from the perspective of maintaining a certain level of proportion of zinc oxide and hydrophobizing agent to further enhance UV protection effect and improve stability, it is more preferable to set the content at 18% by mass or less.

The silica-coated zinc oxide thus obtained can be further surface-treated with a hydrophobic treatment agent to obtain (A) hydrophobic-treated silica-coated zinc oxide.

The hydrophobic treatment agent is not particularly limited, and conventionally known agents can be used. Among these, silicone compounds are preferred, including various silicone oils such as dimethicone (dimethylpolysiloxane), methylphenylpolysiloxane, and methylhydrogenpolysiloxane; various alkylsilanes such as methyltrimethoxysilane, ethyltrimethoxysilane, hexyltrimethoxysilane, and octyltrimethoxysilane; and various fluoroalkylsilanes such as trifluoromethylethyltrimethoxysilane and heptadecafluorodecyltrimethoxysilane. These can be used alone or in combination of two or more.

The content of the hydrophobizing agent relative to the total amount of hydrophobized silica-coated zinc oxide is 9% by mass or more but less than 14% by mass, more preferably 9.5 to less than 14% by mass, and even more preferably 10 to 13% by mass. By having the content of the hydrophobizing agent relative to the total amount of hydrophobized silica-coated zinc oxide be 9% by mass or more, the silica-coated zinc oxide can be uniformly coated with the hydrophobizing agent, improving emulsion stability. Furthermore, by having the content be less than 14% by mass, better UV protection effects can be achieved.

(A) Hydrophobized silica-coated zinc oxide is preferably present in an amount of 8% by mass or more, more preferably 10 to 18% by mass, and most preferably 12 to 16% by mass, relative to the total amount of the oil-in-water emulsion cosmetic. A content of 8% by mass or more ensures sufficient UV protection. Furthermore, a content of 18% by mass or less can reduce the tendency for dryness and noticeable whiteness upon application.

(B) Volatile Acyclic Silicone (B) Volatile acyclic silicone is a silicone oil having a boiling point of 250°C or less at 1 atmosphere (101.325 kPa). Examples of volatile acyclic silicones include volatile linear silicones, and more specifically, low molecular weight linear dimethicones (0.65 cs, 1 cs, 1.5 cs, 2 cs), low molecular weight branched silicones such as methyl trimethicone (TMF-1.5, etc.), and low molecular weight alkyl-modified silicones. Among these, from the viewpoint of improving emulsion stability, volatile linear silicones are preferred, and examples thereof include octamethyltrisiloxane, decamethyltetrasiloxane, and dodecamethylpentasiloxane. One type of (B) volatile acyclic silicone may be used alone, or two or more types may be used in appropriate combination.

The blending amount of (B) volatile acyclic silicone is preferably 8 to 20% by mass, and more preferably 10 to 18% by mass, relative to the total amount of the cosmetic. A blending amount of 8% by mass or more improves the dispersibility of (A) hydrophobically treated silica-coated zinc oxide, while a blending amount of 20% by mass or less can make the skin feel smooth after application and provide a non-greasy, light feel when used.

(C) Organic Acid or Salt Thereof The oil-in-water emulsion cosmetic of the present invention may further contain (C) an organic acid or salt thereof. It is known that the incorporation of an organic acid or salt thereof in an oil-in-water base adversely affects emulsion stability. Furthermore, emulsion stability can also be impaired by the loss of ions from zinc oxide. For this reason, it has been difficult to incorporate an organic acid or salt thereof into compositions containing zinc oxide, such as sunscreens. Furthermore, in the presence of zinc ions, tranexamic acid binds with the zinc ions to precipitate needle-shaped crystals, which not only compromises formulation stability but also causes skin irritation. The oil-in-water emulsion cosmetic of the present invention has high emulsion stability and does not experience aggregation or coalescence of emulsified particles due to poor powder dispersion in the internal phase. Therefore, the hydrophobized powder does not migrate from the internal phase to the external phase or cause zinc ion elution. Therefore, the incorporation of an organic acid or salt thereof does not cause the above-mentioned problems and can prevent skin irritation.

Examples of organic acids or salts thereof include salts of alkoxysalicylic acid and its derivatives; salts of L-ascorbic acid, L-ascorbic acid phosphate, L-ascorbic acid 2-sulfate, L-ascorbic acid 2-glucoside and their derivatives; alkali metal or alkaline earth metal salts such as sodium, potassium, and calcium salts of 4-methoxysalicylic acid, or ammonium salts and amino acid salts; potassium and ammonium salts of glycyrrhizic acid. Examples of tranexamic acid salts include alkali metal salts such as sodium and potassium salts, and alkaline earth metal salts such as calcium and magnesium salts.

The blending amount of (C) organic acid or its salt is 1.0 to 5.0% by mass, preferably 1.0 to 3.0% by mass, of the total amount of the oil-in-water emulsion cosmetic. A blending amount of organic acid or its salt of 1.0% by mass or more provides good skin care effects, while a blending amount of 5.0% by mass or less ensures good stability.

The oil-in-water emulsion cosmetic of the present invention can contain other optional ingredients that can be incorporated into ordinary cosmetics or quasi-drugs, provided that the effects of the present invention are not impaired. Examples of other optional ingredients include, but are not limited to, ultraviolet absorbers, liquid oils and fats, solid oils and fats, waxes, hydrocarbon oils, higher fatty acids, synthetic ester oils, oils other than (B) such as silicone oils, powder ingredients, colorants, moisturizers, aqueous thickeners, dispersants, preservatives, fragrances, various pharmaceuticals, etc.

Examples of ultraviolet absorbers include 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.

Examples of liquid oils include avocado oil, camellia oil, macadamia nut oil, corn oil, olive oil, rapeseed oil, sesame oil, persic oil, wheat germ oil, camellia oil, castor oil, linseed oil, safflower oil, cottonseed oil, perilla oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, Chinese tung oil, Japanese tung oil, jojoba oil, germ oil, and triglycerin.

Examples of solid fats and oils include cocoa butter, coconut oil, hardened coconut oil, palm oil, palm kernel oil, Japan wax kernel oil, hardened oil, Japan wax, and hardened castor oil.

Examples of waxes include beeswax, candelilla wax, cotton wax, carnauba wax, bayberry wax, ivota wax, montan wax, rice bran wax, kapok wax, sugarcane wax, hexyl laurate, jojoba wax, shellac wax, and POE cholesterol ether.

Examples of hydrocarbon oils include liquid paraffin, ozokerite, squalane, pristane, paraffin, ceresin, squalene, petrolatum, microcrystalline wax, and hydrogenated polydecene.

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).

Synthetic ester oils include isopropyl myristate, cetyl octanoate, 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, ethylene glycol di-2-ethylhexanoate, dipentaerythritol fatty acid ester, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, glycerin di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, pentaerythritol tetra-2-ethylhexanoate Glyceryl tri-2-ethylhexanoate, glyceryl trioctanoate, glyceryl triisopalmitate, trimethylolpropane triisostearate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, glyceryl trimyristate, tri-2-heptylundecanoic acid glyceride, castor oil fatty acid methyl ester, oleyl oleate, acetoglyceride, 2-heptyl palmitate Examples include lauroyl undecyl, diisobutyl adipate, 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, 2-ethylhexyl succinate, and triethyl citrate.

Examples of silicone oils include chain polysiloxanes (e.g., methylphenylpolysiloxane, diphenylpolysiloxane, etc.), silicone resins that form a three-dimensional network structure, silicone rubber, and various modified polysiloxanes (amino-modified polysiloxanes, polyether-modified polysiloxanes, alkyl-modified polysiloxanes, fluorine-modified polysiloxanes, etc.).
The above oils can be used alone or in combination of two or more.

Powder ingredients include UV scattering agents such as titanium oxide, iron oxide, and cerium oxide; extender pigments such as talc, mica, kaolin, silica, corn starch, and cellulose; and polymer powders such as polyethylene powder, polymethyl methacrylate powder, and nylon powder.

Examples of moisturizing agents include polyhydric alcohols such as glycerin, 1,3-butylene glycol, dipropylene glycol, and propylene glycol, and water-soluble polymers such as trehalose, hyaluronic acid, and chondroitin sulfate.

Examples of aqueous thickeners include succinoglycan, (dimethylacrylamide/sodium acryloyldimethyltaurate) crosspolymer, cellulose gum, carboxyvinyl polymer, xanthan gum, (hydroxyethyl acrylate/sodium acryloyldimethyltaurate) copolymer, etc.

The oil-in-water emulsion cosmetic of the present invention can be produced, for example, by dispersing powder in the oil phase components using a homomixer or the like, and then adding the resulting oil phase to the aqueous phase using a homomixer or the like, followed by stirring and emulsification.

The oil-in-water emulsion cosmetic of the present invention can be provided as a cosmetic in a variety of formulations, such as a liquid, emulsion, cream, gel, or Bavarian cream form.
Furthermore, the oil-in-water emulsion cosmetic of the present invention can be provided as a skin care cosmetic, a sunscreen cosmetic, a cosmetic containing a coloring agent, a foundation, a makeup base, a BB cream, and the like.

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited thereto. All blend amounts are in mass % unless otherwise specified.

(Examples 1 to 4 and Comparative Examples 1 to 5)
Oil-in-water emulsion cosmetics were prepared according to the formulations shown in Table 1 below, and the prepared cosmetics were evaluated according to the following criteria.

(Rolling stability)
A cylindrical container was half-filled with the prepared oil-in-water emulsion cosmetic (sample), and the sample was subjected to a rolling motion at 45 rpm for 4 hours at room temperature using a rolling tester (manufactured by Nigorikawa Rika Kogyo Co., Ltd.), and the change in the state of the sample was observed and evaluated according to the following criteria.
A: No change observed B: A slight change in viscosity or an increase in emulsified particles observed C: A significant change in viscosity or an increase in emulsified particles observed, causing problems in use

(UV protection effect)
The prepared oil-in-water emulsion cosmetic was dropped at a rate of 2 mg/ ^cm2 onto an S plate (5 x 5 cm V-groove PMMA plate, SPFMASTER-PA01), spread with a finger for 60 seconds, and then dried for 15 minutes, after which the absorbance (400-280 nm) was measured using a Hitachi U-3500 self-recording spectrophotometer. An uncoated plate was used as a control, and the absorbance (Abs) was calculated using the following formula:
Abs=-log(T/To)
T: transmittance of sample, To: transmittance of uncoated plate. The UV protection effect was evaluated by taking the integrated absorbance value of Comparative Example 1 as 100% and the absorbance of each example as a relative value (%).

The formulation and evaluation results are shown in Table 1. The commercial names of the main components shown in Table 1 are listed below.
(Dimethylacrylamide/Sodium acryloyldimethyltaurate) crosspolymer: SU-GEL (manufactured by Toho Chemical Industry Co., Ltd.)
Dimethicone: Silicone KF-96L-1.5CS (Shin-Etsu Silicone Co., Ltd.)

Examples 1 to 4, in which the dimethicone content relative to the total amount of hydrophobic-treated silica-coated zinc oxide was 10% by mass or more, exhibited good rolling stability and improved UV protection efficacy compared to Comparative Example 1, which used cyclic silicone. On the other hand, Comparative Example 2, in which the dimethicone content relative to the total amount of hydrophobic-treated silica-coated zinc oxide was 7.5% by mass, exhibited poor rolling stability and UV protection efficacy, and Comparative Example 3, in which the dimethicone content was 9% by mass, exhibited better UV protection efficacy than Comparative Example 1, but did not achieve satisfactory rolling stability. Although Examples 1 to 4 had a pure zinc oxide content (amount of zinc oxide relative to the total amount of (A)) of 69.5 to 72.5% by mass, which is lower than Comparative Example 3 (pure content of 73.5% by mass), they still exhibited high UV protection efficacy, which is a surprising effect.

Furthermore, as shown in Comparative Example 4, when the dimethicone content relative to the total amount of hydrophobized silica-coated zinc oxide was 14% by mass or higher, rolling stability was achieved, but the UV protection effect was lower than in Comparative Example 1, which used cyclic silicone. At 14% by mass or higher, the effect of the decrease in pure zinc oxide content outweighed the effect of improved dispersibility due to the increased amount of hydrophobizing agent in the silica-coated zinc oxide, presumably resulting in poor UV protection. Comparative Example 5 used the hydrophobized silica-coated zinc oxide used in Example 2 and cyclic silicone as the dispersion medium. While the rolling stability was equivalent to that of Example 2, the UV protection effect was inferior. This result, in which Example 2 had a higher UV protection effect despite using the same hydrophobized silica-coated zinc oxide, is presumably due to the superior affinity of dimethicone, the hydrophobizing agent, over cyclic silicone in terms of dispersibility.

(Examples 5 to 8, Comparative Example 6)
Oil-in-water emulsion cosmetics were prepared according to the formulations shown in Table 2 below, and the prepared cosmetics were evaluated in the same manner as above.

The formulation and evaluation results are shown in Table 2. The commercial names of the main components shown in Table 2 are listed below.
Dimethicone (viscosity 0.9 to 1.1 mm ² /s): Silicone KF-96A-1CS (manufactured by Shin-Etsu Silicone Co., Ltd.)
Dimethicone (viscosity 1.35 to 1.65 mm ² /s): Silicone KF-96L-1.5CS (manufactured by Shin-Etsu Silicone Co., Ltd.)
Dimethicone (viscosity 1.8 to 2.2 mm ² /s): Silicone KF-96A-2CS (manufactured by Shin-Etsu Silicone Co., Ltd.)
Dimethicone (viscosity approximately 6 mm ² /s): Silicone KF-96A-6T (manufactured by Shin-Etsu Silicone Co., Ltd.)

Examples 5 to 8 used the same hydrophobic treated silica-coated zinc oxide as Example 3, but changed the type of dimethicone used as the dispersion medium. When dimethicone, a volatile acyclic silicone, was used alone or in a mixture thereof, no difference was observed in rolling stability or UV protection effect, but in Comparative Example 6, which used non-volatile dimethicone, rolling stability decreased and the UV protection effect was significantly reduced.
Some of the embodiments of the present disclosure are described in [Item 1] to [Item 7] below.
[Item 1]
(A) a hydrophobized silica-coated zinc oxide having an outermost surface hydrophobized with a hydrophobizing agent and having a coating layer containing silica;
(B) a volatile acyclic silicone;
An oil-in-water emulsion cosmetic comprising:
The (A) hydrophobized silica-coated zinc oxide is contained in an internal phase,
an oil-in-water emulsion cosmetic in which the content of the silica relative to the total amount of the hydrophobized silica-coated zinc oxide (A) is 10% by mass or more, and the content of the hydrophobizing treatment agent relative to the total amount of the hydrophobized silica-coated zinc oxide (A) is 9% by mass or more and less than 14% by mass.
[Item 2]
2. The oil-in-water emulsion cosmetic according to item 1, wherein the hydrophobic treatment agent is dimethicone.
[Item 3]
3. The oil-in-water emulsion cosmetic according to item 2, wherein the content of the hydrophobic treatment agent relative to the total amount of the hydrophobic treated silica-coated zinc oxide (A) is 10 to 13% by mass.
[Item 4]
4. The oil-in-water emulsion cosmetic according to item 1, 2, or 3, wherein the (A) hydrophobized silica-coated zinc oxide is contained in an amount of 8% by mass or more based on the total amount of the cosmetic.
[Item 5]
5. The oil-in-water emulsion cosmetic according to any one of items 1 to 4, wherein the volatile acyclic silicone (B) is a volatile linear silicone.
[Item 6]
Item 6. The oil-in-water emulsion cosmetic according to Item 5, wherein the volatile linear silicone is octamethyltrisiloxane, decamethyltetrasiloxane, or dodecamethylpentasiloxane.
[Item 7]
7. The oil-in-water emulsion cosmetic according to any one of items 1 to 6, further comprising (C) an organic acid or a salt thereof.

Claims (5)

(A) a hydrophobized silica-coated zinc oxide having an outermost surface hydrophobized with a hydrophobizing agent and having a coating layer containing silica;
(B) a volatile acyclic silicone;
An oil-in-water emulsion cosmetic comprising:
The (A) hydrophobized silica-coated zinc oxide is contained in an internal phase,
the content of the hydrophobized silica-coated zinc oxide (A) is 8% by mass or more relative to the total amount of the cosmetic;
the content of the (B) volatile acyclic silicone is 8 to 20% by mass relative to the total amount of the cosmetic;
the content of the silica relative to the total amount of the hydrophobized silica-coated zinc oxide (A) is 10% by mass or more, and the content of the hydrophobizing agent relative to the total amount of the hydrophobized silica-coated zinc oxide (A) is 9.5% by mass or more but less than 14% by mass,
the (B) volatile acyclic silicone is a volatile linear silicone,
The hydrophobic treatment agent is at least one selected from the group consisting of dimethicone, methylphenylpolysiloxane, and methylhydrogenpolysiloxane .
Oil-in-water emulsion cosmetics. The oil-in-water emulsion cosmetic according to claim 1, wherein the hydrophobic treatment agent is dimethicone. The oil-in-water emulsion cosmetic according to claim 2, wherein the content of the hydrophobic treatment agent relative to the total amount of the hydrophobic treated silica-coated zinc oxide (A) is 10 to 13 mass%. The oil-in-water emulsion cosmetic according to any one of claims 1 to 3, wherein the volatile linear silicone is octamethyltrisiloxane, decamethyltetrasiloxane, or dodecamethylpentasiloxane. The oil-in-water emulsion cosmetic according to any one of claims 1 to 4 , further comprising (C) an organic acid or a salt thereof.