JP7628080B2 - Water-in-oil composition - Google Patents

Description

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This application claims priority to Japanese Patent Application No. 2019-161685, filed September 5, 2019, the entire disclosure of which is incorporated herein by reference.

The present invention relates to a water-in-oil composition, and in particular to an improvement in the dispersibility of a hydrophobized powder thereof.

Hydrophobic powders are applied to various cosmetics, etc., because they exhibit water resistance on the applied surface and are less likely to fall off due to sweat, etc. For example, sunscreen cosmetics are widely used to reduce the effects of ultraviolet rays on the skin, and these are roughly divided into those that use ultraviolet scattering powders as an ultraviolet screening agent and those that use organic ultraviolet absorbers as an ultraviolet screening agent.
Many organic ultraviolet absorbents are classified as ester oils, which can be dissolved in an oil phase and can be easily applied uniformly to the skin, but they can also be irritating to the skin.
In contrast, fine particles of zinc oxide and fine particles of titanium dioxide are usually used for ultraviolet scattering powders, and by adjusting the particle size, the transmittance of visible light is improved and an ultraviolet scattering effect is obtained. In order to obtain water resistance, the surface of the ultraviolet scattering powder is often hydrophobized and blended into the oil phase.
However, hydrophobically treated inorganic powders tend to aggregate and settle even in the oil phase, which can cause the composition to become cloudy and non-uniform, and can also cause whitening when applied to the skin.

Patent No. 4536538 JP 2006-213619 A Patent No. 4881961 JP 2010-159229 A

The present invention has been made in consideration of the above-mentioned conventional technology, and the problem to be solved is to provide a water-in-oil composition in which hydrophobic powder is blended in the oil phase and in which powder aggregation and sedimentation are unlikely to occur.

In order to solve the above problems, the water-in-oil composition according to the present invention comprises:
an oil phase having a silicone oil/oil phase mass ratio of 0.75 or more;
a silicone-treated ultraviolet scattering powder dispersed in an oil phase and treated with a silicone-based surface treatment agent;
a polyglycerin-modified silicone dispersant for dispersing the silicone-treated UV scattering powder in an oil phase;
an aqueous phase dispersed in an oil phase;
an emulsifier for dispersing the aqueous phase in the oil phase;
Including,
The silicone-treated ultraviolet scattering powder has an average primary particle size of 1 to 100 nm;
The silicone-based surface treatment agent is either a dimethicone treatment agent or a hydrogen dimethicone treatment agent,
the silicone-treated ultraviolet scattering powder is at least one selected from titanium oxide coated with hydrogen dimethicone/hydrated silica, titanium oxide coated with hydrogen dimethicone/aluminum hydroxide, zinc oxide coated with dimethicone/hydrated silica, and zinc oxide coated with hydrogen dimethicone;
the polyglycerin-modified silicone dispersant is at least one selected from bisbutyldimethicone polyglyceryl-3, polyglyceryl-3 polydimethylsiloxyethyl dimethicone, and lauryl polyglyceryl-3 polydimethylsiloxyethyl dimethicone;
the emulsifier is a polyether-modified silicone emulsifier, and the content of the emulsifier in the composition is 0.5% by mass to 7% by mass;
The mass ratio of the silicone-treated UV scattering powder to the total UV scattering powder is 0.7 or more.
In addition, in the composition,
The aqueous phase is present in an amount of 20 to 35% by mass in the composition;
The oil phase is present in an amount of 20 to 40% by mass in the composition;
The silicone-treated UV scattering powder is preferably present in an amount of 10 to 35% by mass in the composition.
In addition, in the composition,
The average emulsion particle size of the aqueous phase is preferably 10 μm or less.
In addition, in the composition,
It is preferable that the composition further contains an organically modified clay mineral.
In addition, in the composition,
The amount of dispersant other than the polyglycerin-modified silicone dispersant in the composition is preferably less than 0.5% by mass.
In addition, in the composition,
It is preferred that the cyclic siloxanes constitute less than 10% by weight of the composition.
In addition, in the composition,
The polyglycerin modified silicone dispersant is preferably bisbutyldimethicone polyglyceryl-3.
In addition, in the composition,
The content of the polyglycerin-modified silicone dispersant in the composition is preferably 0.5% to 1.5% by mass.
In addition, in the composition,
The content of the silicone-treated UV scattering powder in the composition is preferably 15 to 30% by mass.

The water-in-oil composition of the present invention disperses a silicone-treated powder in an oil phase mainly made of silicone oil, uses a polyglycerin-modified silicone dispersant as a dispersant, and disperses an aqueous phase in the oil phase, thereby maintaining the silicone-treated powder stable in the composition and inhibiting aggregation and sedimentation.

Preferred embodiments of the present invention will now be described.
The water-in-oil composition of the present invention comprises an aqueous phase and a silicone-treated powder separately dispersed in an oil phase.
[Oil phase]
In the present invention, the dispersion medium is an oil phase, and in particular in the present invention, when the dispersion medium is mainly composed of silicone oil and contains other oily components, it is suitable that the mass ratio of silicone oil/oil phase is 0.65 or more, preferably 0.75 or more.
Examples of silicone oils include dimethylpolysiloxane, octamethylsiloxane, decamethyltetrasiloxane, methylhydrogenpolysiloxane, methylphenylpolysiloxane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane.
When a cyclic siloxane is contained, its amount in the composition is preferably 10% by mass or less.
Other oily components include various liquid oils and fats, ester oils, hydrocarbon oils, solid oils and fats, and the like.
Examples of liquid oils and fats 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, 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, triglycerin, and the like.

Examples of 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, isononyl isononanoate, 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, and pentaerythritol tetra-2-ethylhexanoate. Taerythritol, glycerin tri-2-ethylhexanoate, glycerin trioctanoate, glycerin triisopalmitate, trimethylolpropane triisostearate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, glycerin trimyristate, tri-2-heptylundecanoate glyceride, castor oil fatty acid methyl ester, oleyl oleate, acetoglyceride, palmitic acid 2- Examples include heptylundecyl, 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 the hydrocarbon oil include liquid paraffin, ozokerite, squalane, pristane, paraffin, ceresin, squalene, petrolatum, microcrystalline wax, polyethylene wax, and Fischer-Tropsch wax.
[Silicone-treated powder]
In the present invention, the silicone-treated powder particularly includes inorganic powder that has been surface-treated with silicone.
Preferably, silicone-treated titanium dioxide and/or zinc oxide are used.

When these silicone-treated powders are used as UV scattering agents, it is preferable that the titanium dioxide and zinc oxide are prepared in the form of fine particles from the viewpoint of the UV scattering effect. The fine particle titanium dioxide preferably has an average primary particle diameter of 1 to 100 nm, and the fine particle zinc oxide preferably has an average primary particle diameter of 1 to 100 nm. However, it is not limited to these.

The method of siliconization is not particularly limited, and can be any known method. Examples include treatment using silicones such as methylhydrogenpolysiloxane, methylhydrogenpolysiloxane-dimethylpolysiloxane copolymer, and dimethylpolysiloxane; and treatment using silane compounds such as octyltriethoxysilane and hexyltrimethoxysilane.

Particularly preferred silicone treatments include dimethicone treatment, hydrogen dimethicone treatment, and octylethoxysilane treatment.

The amount of the silicone-treated powder to be blended is 10 to 35% by mass, preferably 15 to 30% by mass, relative to the composition of the present invention. If the amount is less than 10% by mass, the effects of the silicone-treated powder, such as water resistance, are not sufficiently obtained, while if the amount is more than 35% by mass, there is a concern that the usability will deteriorate over time, as typified by odor changes and squeaking.
The siliconization treatment agent is not particularly limited, and can be any known agent.Among them, silicone compounds are preferred, and for example, various silicone oils such as dimethylpolysiloxane (dimethicone), methylphenylpolysiloxane, methylhydrogenpolysiloxane, etc., various alkylsilanes such as methyltrimethoxysilane, ethyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, etc., and various fluoroalkylsilanes such as trifluoromethylethyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, etc. can be used alone or in combination of two or more.

m=３０～１００、好ましくは５０～７０(試験例で用いたものは平均６０)
n=１～５、好ましくは２～３（試験例で用いたものは、平均３）
本発明においてポリグリセリン変性シリコーン分散剤は、シリコーン処理粉体の配合量にもよるが、組成物中０．５～５質量％、好ましくは１～３質量％であることが好ましい。
なお、ポリグリセリン変性シリコーン分散剤以外の分散剤が配合される場合には、組成物中０．５質量％未満であることが好ましい。 [Polyglycerin-modified silicone dispersant]
In the present invention, it is necessary to use a polyglycerin-modified silicone dispersant as a dispersant for the silicone-treated powder.
The polyglycerin-modified silicone dispersant preferably has a polyglycerin skeleton in the main skeleton and silicone chains at both ends. This silicone-terminated polyglycerin has almost no ability to form a water-in-oil composition, that is, as an emulsifier, but in the present invention, it exhibits excellent ability to disperse silicone-treated powder in the oil phase.
More specifically, those having the following structure are preferably used.

m = 30 to 100, preferably 50 to 70 (the average value used in the test example is 60)
n=1 to 5, preferably 2 to 3 (the average used in the test examples is 3)
In the present invention, the amount of the polyglycerin-modified silicone dispersant in the composition is preferably 0.5 to 5% by mass, and more preferably 1 to 3% by mass, although this will vary depending on the amount of the silicone-treated powder.
When a dispersant other than the polyglycerin-modified silicone dispersant is added, its amount is preferably less than 0.5% by mass in the composition.

[Aqueous phase]
In the present invention, the aqueous phase constituting the internal phase is dispersed in the oil phase of the external phase, and the presence of the internal aqueous phase inhibits settling of the silicone-treated powder.
Examples of components contained in the aqueous phase include water , alcohols , and water-soluble polymers.
Examples of alcohols include lower alcohols such as ethanol and isopropanol, higher alcohols such as isostearyl alcohol, octyldodecanol and hexyldecanol, and polyhydric alcohols such as ethylene glycol, propylene glycol, 1,3-butylene glycol, dipropylene glycol and polybutylene glycol.

Examples of water-soluble polymers include homopolymers and copolymers of 2-acrylamido-2-methylpropanesulfonic acid (hereinafter abbreviated as "AMPS"). The copolymers are copolymers made with comonomers such as vinylpyrrolidone, acrylic acid amide, sodium acrylate, and hydroxyethyl acrylate. Examples include AMPS homopolymer, vinylpyrrolidone/AMPS copolymer, dimethylacrylamide/AMPS copolymer, acrylic acid amide/AMPS copolymer, and sodium acrylate/AMPS copolymer.

Further examples include carboxyvinyl polymer, ammonium polyacrylate, sodium polyacrylate, sodium acrylate/alkyl acrylate/sodium methacrylate/alkyl methacrylate copolymer, carrageenan, pectin, mannan, curdlan, chondroitin sulfate, starch, glycogen, gum arabic, sodium hyaluronate, tragacanth gum, xanthan gum, mucoitin sulfate, hydroxyethyl guar gum, carboxymethyl guar gum, guar gum, dextran, keratosulfuric acid, locust bean gum, succinoglucan, chitin, chitosan, carboxymethyl chitin, agar, and the like.
In the present invention, the aqueous phase has the effect of preventing the siliconized powder from agglomerating and settling in the composition, and its blending amount in the composition is 10 to 35% by mass, preferably 20 to 30% by mass.

p＝30～50
q＝1～3
r＝2～4
a＝3～12
b＝7～13

[emulsifier]
In the present invention, examples of the water-in-oil emulsifier that disperses the aqueous phase in the oil phase include emulsifiers with a low HLB, and it is particularly preferable to use a polyether-modified silicone in which polyethylene oxide groups are bonded in a pendant manner to a silicone backbone.

p = 30 to 50
q=1 to 3
r = 2 to 4
a = 3 to 12
b=7-13

In the present invention, the blending amount of the water-in-oil emulsifier is preferably 0.5 to 7% by mass, more preferably 2 to 5% by mass, in the composition.
In addition to the above-mentioned essential components, the water-in-oil composition of the present invention can be produced by a conventional method by appropriately blending, as necessary, components usually used in external skin preparations such as cosmetics and pharmaceuticals, such as whitening agents, moisturizing agents, antioxidants, oily components, other UV absorbers, surfactants, thickeners, alcohols, powder components, colorants, aqueous components, water, various skin nutrients, etc.

The water-in-oil composition of the present invention can be prepared by a conventional method used for producing water-in-oil emulsion compositions. For example, the oil phase is appropriately heated to dissolve uniformly, silicone-treated powder is dispersed in the oil phase using a homomixer, and then a separately prepared aqueous phase is gradually added to the oil phase while emulsifying using a homomixer.

Prior to describing specific embodiments, a manufacturing method and an evaluation method will be described below.
[Production method]
The powder was dispersed in the oil component mixed using a homomixer, and then a well-mixed aqueous component was added to obtain a composition.
[Evaluation method]
A 2 mg/ ^cm2 drop was applied to a PMMA skin simulant plate (SPFMASTER-PA01), applied with a finger for 60 seconds, and dried for 15 minutes to form a coating film. Using an uncoated plate as a control, the absorbance (400-280 nm) of the coating film was measured using a Hitachi U-3500 self-recording spectrophotometer, and the integrated absorbance and absorbance at 300 nm were calculated from the obtained measurement data. In addition, a uniform film of any thickness of 10 um-50 um was prepared, and the transparency of samples of the same thickness was visually confirmed.
The transparency was evaluated according to the following criteria.
A: Extremely transparent B: Transparent C: Transparent but with a slight whiteness D: Little transparency and whiteness

Specific embodiments of the present invention will now be described.
First, the present inventors investigated the dispersibility of hydrophobically treated powder when it was blended in a water-in-oil composition.
The results are shown in Table 1.

Comparing the Test Examples 1-1 to 1-3 in Table 1, the Test Examples 1-1 and 1-2, which were treated with silicone (hydrogen dimethicone coating treatment), showed little formation of aggregates and had high composition transparency, but the Test Example 1-3, which was treated with stearic acid, showed a decrease in transparency and powder aggregation. Similarly, comparing the Test Examples 1-4 to 1-6, the hydrogen dimethicone coating (Test Example 1-4) also showed no formation of aggregates, while the triethoxycaprylylsilane coating (Test Example 1-5) and the palmitic acid dextrin coating (Test Example 1-6) showed formation of aggregates and a decrease in transparency.
For the above reasons, in the present invention, the hydrophobic treatment must be a silicone treatment.
Next, the present inventors investigated the mass ratio of silicone-treated powder to total powder.
As shown in Test Examples 1-7 to 1-9 in Table 1(B), when the silicone-treated powder/total powder ratio is less than 0.7, a decrease in transparency is observed. For this reason, it is preferable that the silicone-treated powder/total powder ratio is 0.7 or more.

The inventors also investigated the mass ratio of silicone oil in the oil phase. The results are shown in Table 2.

表２より、基本的に本発明の油相はシリコーン油であることが好ましいが、他の油分（セバシン酸ジイソプロピル）を含む場合には、シリコーン油の質量比が０．６５以上、好ましくは０．７５以上であることが好ましい。

As can be seen from Table 2, the oil phase of the present invention is preferably silicone oil in principle, but when other oils (diisopropyl sebacate) are contained, the mass ratio of the silicone oil is preferably 0.65 or more, and more preferably 0.75 or more.

Furthermore, the inventors investigated dispersants that disperse the silicone-treated powder in the oil phase. The results are shown in Table 3.

前記表３より、ポリグリセリン変性シリコーン分散剤が特に好適に用いられ、イソステアリン酸などの一般的な分散剤では十分な分散効果が得られなかった。

As can be seen from Table 3 above, polyglycerin-modified silicone dispersants are particularly suitable, and a sufficient dispersing effect cannot be obtained with general dispersants such as isostearic acid.

なお、粉末の再分散性については、以下のように評価した。
Ｃ：数回振っても再分散しない
Ｂ：数回振ると再分散する
Ａ：１，２回振ると再分散する

表４より明らかなように、組成物中の水相が２０質量％未満となると粉末のケーキングが生じるようになる。このため、本発明にかかる油中水型組成物の水相は、２０質量％以上であることが好ましい。


The present inventors have investigated the aqueous phase ratio in water-in-oil compositions. The results are shown in Table 4.

The redispersibility of the powder was evaluated as follows.
C: Does not redisperse even after shaking several times B: Redisperses after shaking several times A: Redisperses after shaking once or twice

As is clear from Table 4, when the aqueous phase in the composition is less than 20% by mass, caking of the powder occurs. Therefore, the aqueous phase of the water-in-oil composition according to the present invention is preferably 20% by mass or more.

Claims (9)

an oil phase having a silicone oil/oil phase mass ratio of 0.75 or more;
a silicone-treated ultraviolet scattering powder that is dispersed in the oil phase and treated with a silicone-based surface treatment agent;
a polyglycerin-modified silicone dispersant for dispersing the silicone-treated ultraviolet scattering powder in an oil phase;
an aqueous phase dispersed in the oil phase;
an emulsifier for dispersing the aqueous phase in an oil phase;
Including,
The silicone-treated ultraviolet scattering powder has an average primary particle size of 1 to 100 nm;
The silicone-based surface treatment agent is either a dimethicone treatment agent or a hydrogen dimethicone treatment agent,
the silicone-treated ultraviolet scattering powder is at least one selected from titanium oxide coated with hydrogen dimethicone/hydrated silica, titanium oxide coated with hydrogen dimethicone/aluminum hydroxide, zinc oxide coated with dimethicone/hydrated silica, and zinc oxide coated with hydrogen dimethicone;
The polyglycerin-modified silicone dispersant is at least one selected from bisbutyldimethicone polyglyceryl-3, polyglyceryl-3 polydimethylsiloxyethyl dimethicone, and lauryl polyglyceryl-3 polydimethylsiloxyethyl dimethicone;
the emulsifier is a polyether-modified silicone emulsifier, and the content of the emulsifier in the composition is 0.5% by mass to 7% by mass;
A water-in-oil composition, characterized in that the mass ratio of silicone-treated UV scattering powder to total UV scattering powder is 0.7 or more. 2. The composition of claim 1 ,
The aqueous phase is present in an amount of 20 to 35% by mass in the composition;
The oil phase is present in an amount of 20 to 40% by mass in the composition;
The silicone- treated ultraviolet scattering powder is present in an amount of 10 to 35% by mass in the composition. In the composition according to claim 1 or 2,
A water-in-oil composition, characterized in that the average emulsion particle size of the aqueous phase is 10 μm or less. In the composition according to any one of claims 1 to 3,
A water-in-oil composition further comprising an organically modified clay mineral. In the composition according to any one of claims 1 to 4,
A water-in-oil composition, characterized in that the amount of dispersant other than the polyglycerin-modified silicone dispersant in the composition is less than 0.5% by mass. In the composition according to any one of claims 1 to 5,
A water-in-oil composition, comprising less than 10% by weight of cyclic siloxane. In the composition according to any one of claims 1 to 6,
A water-in-oil composition, characterized in that the polyglycerin-modified silicone dispersant is bis-butyldimethicone polyglyceryl-3. In the composition according to any one of claims 1 to 7,
A water-in-oil composition, characterized in that the content of the polyglycerin-modified silicone dispersant in the composition is 0.5% by mass to 1.5% by mass. The composition according to any one of claims 1 to 8 ,
A water-in-oil type composition, characterized in that the content of the silicone-treated ultraviolet scattering powder in the composition is 15 to 30 mass %.