Cosmetic containing hydrophobized powder

Abstract

This invention provides a cosmetic having good stability and capable of achieving a high ultraviolet protection effect. This cosmetic contains (A1) a first hydrophobized powder and (B) water, wherein an (A1) component is dispersed in an aqueous phase, and the average particle diameter of secondary particles in the (A1) component in the aqueous phase is 150 nm or less.

Description

Cosmetics containing hydrophobically treated powder

[0001] The present invention relates to a cosmetic comprising a hydrophobized powder, and more particularly to a cosmetic comprising a hydrophobized powder in an aqueous phase, the average secondary particle size of which is 150 nm or less.

[0002] The purpose of sunscreen cosmetics is to block ultraviolet rays in sunlight and protect the skin from the harmful effects of ultraviolet rays. To achieve a high SPF (Sun Protection Factor) value by blocking ultraviolet radiation from reaching the skin, it is conceivable to incorporate a high amount of ultraviolet scattering agents. However, this can reduce the transparency of the base, cause a feeling of burden on the skin when applied, or cause the skin to become white after application. A cosmetic composition that has a high SPF value while reducing the feeling of burden on the skin has been proposed (Patent Document 1), in which a powder such as an ultraviolet scattering agent is dispersed in an oil phase by a dispersion method using cavitation.

[0003] Powders of metal oxides or the like whose surfaces have been hydrophobized are known as ultraviolet scattering agents, etc. Such powders are usually present in large amounts in an oil phase, and in order to make them present in an aqueous phase, it is necessary to improve the dispersion state.

[0004] International Publication No. 2020 / 100803

[0005] The inventors of the present invention have surprisingly discovered through their investigations that by dispersing a hydrophobized powder having an average secondary particle size of 150 nm or less in the aqueous phase of a cosmetic, it is possible to achieve good stability and a high UV protection effect. The present invention is based on these findings.

[0006] The present invention provides the following inventions. [1] A cosmetic comprising (A1) a first hydrophobically treated powder and (B) water, wherein component (A1) is dispersed in an aqueous phase, and the average particle size of secondary particles of component (A1) in the aqueous phase is 150 nm or less. [2] The cosmetic according to [1], wherein the aqueous phase further comprises (C) a polyether-modified silicone or polyoxyethylene alkyl ether having an HLB of 5 to 18. [3] The cosmetic according to [1] or [2], further comprising (A2) a second hydrophobically treated powder and (D) an oil component, wherein component (A2) is dispersed in an oil phase, and the average particle size of secondary particles of component (A2) in the oil phase is 150 nm or less. [4] The cosmetic according to [3], wherein the oil phase further comprises (E) glycerin modified at both ends with silicone. [5] The cosmetic preparation according to [3] or [4], wherein the combined amount of component (A1) and component (A2) is 30% by mass or less relative to the total amount of the cosmetic preparation. [6] The cosmetic preparation according to any of [3] to [5], wherein the combined amount of component (A1) is 10 to 100% by mass relative to the combined amount of component (A1) and component (A2). [7] The cosmetic preparation according to any of [1] to [6], wherein the combined amount of component (A1) is 10 to 100% by mass relative to the combined amount of component (A1) and component (A2). [8] The cosmetic preparation according to any of [1] to [7], wherein the combined amount of component (A1) is an oil-in-water emulsion cosmetic preparation. [9] The cosmetic preparation according to [1], wherein the combined amount of component (A1) is 10 to 100% by mass relative to the combined amount of component (A1) and component (A2).

[10] A method for producing the cosmetic preparation according to [1], comprising: an aqueous mixture preparation step of mixing component (A1) and water to prepare an aqueous mixture; and an aqueous phase dispersion step of passing the aqueous mixture through a throttle channel as a high-pressure fluid at 50 to 200 MPa, and dispersing component (A1) in an aqueous phase by cavitation generated in the throttle channel.

[10] The production method according to [9], further comprising: an oily mixture preparation step of mixing component (A2) and an oil to prepare an oily mixture; and an oil phase dispersion step of passing the oily mixture through a throttle channel as a high-pressure fluid at 50 to 200 MPa, and dispersing component (A2) in an oil phase by cavitation generated in the throttle channel.

[0007] According to the present invention, it is possible to provide a cosmetic preparation that has good stability and can achieve a high UV protection effect. Furthermore, the cosmetic preparation according to the present invention can suppress a decrease in the transparency of the base, reduce the feeling of burden on the skin, and improve the feeling of use. Specific Description of the Invention

[0008] [Cosmetic] The present invention relates to a cosmetic comprising (A1) a first hydrophobized powder (hereinafter sometimes referred to as component (A1), the same applies to other components) and (B) water. Component (A1) is dispersed in an aqueous phase, and the average particle size of its secondary particles is 150 nm or less, preferably 10 to 130 nm. One of the characteristics of the cosmetic according to the present invention is that aggregation of powder particles is significantly suppressed, resulting in a small secondary particle size of the powder particles. Cosmetics according to the present invention include those in which the powder remains dispersed over a normal storage period, and further include those in which the powder settles during a normal storage period in the art, but can be redispersed by stirring the cosmetic or shaking the container using a method normal in the art.

[0009] The cosmetic according to the present invention may further comprise an oil phase. Preferably, the cosmetic according to the present invention further comprises (A2) a second hydrophobically treated powder and (D) an oil component. In this case, the component (A2) is dispersed in the oil phase, and the average particle size of the secondary particles is 150 nm or less, preferably 10 to 130 nm. In a preferred embodiment of the present invention, the components (A1) and (A2) are dispersed in both the aqueous phase and the oil phase, respectively, with an average particle size of 150 nm or less.

[0010] The average particle size of the secondary particles of the hydrophobic treated powder can be measured by dynamic light scattering to measure the average particle size and particle size distribution of submicron particles dispersed in a liquid. The average particle size of the primary particles can be measured by nitrogen adsorption.

[0011] (A1) First Hydrophobically Treated Powder Component (A1) is a hydrophobically treated powder dispersed in the aqueous phase of a cosmetic, with the average particle size of its secondary particles being 150 nm or less. The hydrophobically treated powder is preferably a hydrophobically treated metal oxide powder. The hydrophobically treated powder is preferably a powder with ultraviolet scattering function, i.e., an ultraviolet scattering agent. The average primary particle size of the hydrophobically treated powder is generally 10 nm or more and 100 nm or less. Specific examples of hydrophobically treated metal oxides include titanium oxide, zinc oxide, cerium oxide, talc, silica, mica, sericite, kaolin, mica titanium, black iron oxide, yellow iron oxide, red iron oxide, ultramarine, Prussian blue, chromium oxide, and chromium hydroxide. Of these, titanium oxide and zinc oxide are preferred due to their high ultraviolet scattering function. Composite powders in which particles made of a material other than titanium oxide are coated with titanium oxide can also be used.

[0012] The hydrophobic treatment applied to the powder may be a treatment to introduce hydrophobic groups onto the particle surface or to form a coating of a hydrophobic substance. Specifically, the hydrophobic treatment may be a wet method using a solvent, a gas phase method, a mechanochemical method, or the like. Furthermore, the treating agent used in the hydrophobic treatment may be silicones such as methylhydrogenpolysiloxane, dimethylpolysiloxane, and triethoxycaprylylsilane, dextrin fatty acid esters, higher fatty acids, higher alcohols, fatty acid esters, metal soaps, alkyl phosphate ethers, fluorine compounds, or hydrocarbons such as squalane and paraffin. Because component (A1) is dispersed in the aqueous phase, silicone treatment is preferred as the hydrophobic treatment.

[0013] The component (A1) may be blended in one or more types. The blending amount of the component (A1) is preferably 0.1 to 30% by mass, more preferably 0.5 to 10% by mass, and even more preferably 1 to 3% by mass, relative to the total amount of the cosmetic.

[0014] (A2) Second Hydrophobically Treated Powder The cosmetic preparation according to the present invention may further comprise (A2) a second hydrophobically treated powder. Component (A2) is a hydrophobically treated powder that is dispersed in the oil phase of the cosmetic preparation, and the average particle size of its secondary particles is 150 nm or less. Component (A1) and component (A2) may be the same or different. Preferred components (A2) are the same as those described above for component (A1).

[0015] The component (A2) can be blended in one type or two or more types. The blending amount of the component (A2) is preferably 0.5 to 15 mass %, and more preferably 1 to 10 mass %, based on the total amount of the cosmetic.

[0016] The combined amount of component (A1) and component (A2) is preferably 30% by mass or less, more preferably 1 to 20% by mass, and even more preferably 2 to 12% by mass, relative to the total amount of the cosmetic. In the cosmetic according to the present invention, aggregation of the hydrophobized powder is suppressed and the powder is dispersed with a small secondary particle size, thereby achieving a high UV protection effect with a smaller amount than that of powders typically used. By suppressing the amount of hydrophobized powder added to the cosmetic, it is possible to suppress a decrease in the transparency of the base and also improve the feel when used.

[0017] (B) Water The cosmetic according to the present invention comprises (B) water. As the water, water used in cosmetics, quasi-drugs, etc. can be used, such as purified water, ion-exchanged water, tap water, etc. The blending amount of water is preferably 10 to 35% by mass, more preferably 10 to 25% by mass, based on the total amount of the cosmetic according to the present invention.

[0018] (C) Polyether-Modified Silicone or Polyoxyethylene Alkyl Ether The cosmetic according to the present invention preferably further comprises (C) a polyether-modified silicone or a polyoxyethylene alkyl ether in the aqueous phase. Component (C) can improve the dispersion state of component (A1) in the aqueous phase. The HLB (hydrophile-lipophile balance) of component (C) is 5 to 18, more preferably 5 to 16, and even more preferably 6 to 10. Being within this range can improve the initial dispersibility and dispersion stability of component (A1) in the aqueous phase. In the present invention, the HLB value is a value calculated by the Griffin method.

[0019] Component (C) is preferably a polyether-modified silicone. The polyether-modified silicone is preferably a dimethicone having a PEG chain and / or a PPG chain, more preferably a dimethicone having a PEG chain. The average number of moles of alkylene oxide added may be 8 or more and 40 or less. Alternatively, it may be an alkyl ether of dimethicone having a PEG and / or PPG chain terminal. A preferred example of a polyether-modified silicone is PEG-12 dimethicone. The silicone chain of the polyether-modified silicone may be linear or branched, but is preferably linear. It may also be a polyether-modified alkyl-modified silicone further having an alkyl side chain, but is preferably unalkyl-modified.

[0020] The component (C) may be blended in one or more types. The blending amount of the component (C) is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, and even more preferably 0.05 to 1% by mass, relative to the total amount of the cosmetic.

[0021] (D) Oil The cosmetic composition according to the present invention may further comprise (D) oil. Examples of component (D) include silicone oil, hydrocarbon oil, higher fatty acid, higher alcohol, ester oil, and liquid fat and oil, with silicone oil, hydrocarbon oil, and ester oil being preferred. Examples of silicone oil include dimethicone, methylphenylpolysiloxane, methylhydrogenpolysiloxane, methicone hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, hexadecamethylheptasiloxane, and caprylyl methicone. Examples of hydrocarbon oil include isododecane, isohexadecane, isoparaffin, liquid paraffin, ozokerite, squalane, pristane, paraffin, ceresin, squalene, petrolatum, and microcrystalline wax.Examples of ester oils include octyl octanoate, nonyl nonanoate, cetyl octanoate, isopropyl myristate, octyldodecyl myristate, isopropyl palmitate, ethylhexyl 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 esters, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, tripropylene glycol pivalate, diisostearyl malate, glycerin di-2-heptylundecanoate, glycerin diisostearate, trimethylolpropane tri-2-ethylhexanoate, triisostearate Trimethylolpropane, pentaerythritol tetra-2-ethylhexanoate, glycerin tri-2-ethylhexanoate, glycerin trioctanoate, glycerin triisopalmitate, trimethylolpropane triisostearate, cetyl 2-ethylhexanoate-2-ethylhexyl palmitate, glycerin trimyristate, tri-2-heptylundecanoic acid glyceride, castor oil fatty acid methyl ester, oleyl oleate, acetoglyceride, Examples of the alkyl acrylate include 2-heptylundecyl palmitate, diisobutyl adipate, 2-octyldodecyl N-lauroyl-L-glutamate, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, 2-ethylhexyl succinate, triethyl citrate, and cetyl ethylhexanoate.

[0022] The component (D) may be blended in one or more types. The blending amount of the component (D) is preferably 10 to 80 mass %, more preferably 20 to 60 mass %, based on the total amount of the cosmetic.

[0023] (E) Glycerin modified at both ends with silicone The cosmetic composition according to the present invention may further comprise (E) glycerin modified at both ends with silicone. Component (E) can improve the dispersion state of component (A2) in the oil phase. Component (E) is preferably represented by formula (1). In the formula, R １ is C １－１２ R is an alkyl group or a phenyl group, preferably a methyl group; ２ is C ２－１１ It is an alkylene group, preferably a trimethylene group, m is 10 to 120, and n is 1 to 11. The alkyl group and alkylene group may be linear or branched. The weight-average molecular weight of component (E) is preferably 2,000 to 30,000. The weight-average molecular weight can be calculated, for example, by gel permeation chromatography using polystyrene standards. Examples of component (E) include bisbutyldimethicone polyglyceryl-3.

[0024] The component (E) can be blended in one type or two or more types. The blending amount of the component (E) is preferably 0.1 to 20 mass %, more preferably 0.5 to 10 mass %, based on the total amount of the cosmetic.

[0025] The cosmetic composition of the present invention may contain other ingredients that are commonly used in cosmetics, other than those mentioned above, to the extent that the effects of the present invention are not impaired. Examples of these ingredients include thickeners, moisturizers, UV absorbers, drugs, stabilizers, pH adjusters, preservatives, pigments, dyes, surfactants, powder components, fragrances, etc.

[0026] [Method for producing a cosmetic product] The method for producing a cosmetic product according to the present invention is not particularly limited, but in one preferred embodiment, it comprises the following steps: (I) an aqueous mixture preparation step of mixing component (A1) and water to prepare an aqueous mixture; and (II) an aqueous phase dispersion step of passing the aqueous mixture through a throttle channel as a high-pressure fluid of 50 to 200 MPa and dispersing component (A1) in an aqueous phase by generating cavitation within the throttle channel. The method for producing a cosmetic product according to the present invention can further comprise the following steps: (III) an oily mixture preparation step of mixing component (A2) and an oil to prepare an oily mixture; and (IV) an oily phase dispersion step of passing the oily mixture through a throttle channel as a high-pressure fluid of 50 to 200 MPa and dispersing component (A2) in an oil phase by generating cavitation within the throttle channel.

[0027] (I) Aqueous Mixture Preparation Step In this step, water as a dispersion medium, component (A1), and optional components as needed are mixed with stirring to prepare an aqueous mixture. In this step, it is preferable to include component (C) as an optional component for improving dispersibility. Examples of other optional components include a humectant, a stabilizer, a preservative, and a thickener.

[0028] (II) Aqueous Phase Dispersion Step In this step, the aqueous mixture prepared in step (I) is homogenized based on the principle of cavitation to prepare an aqueous phase dispersion. Cavitation is a physical phenomenon in which bubbles appear and disappear in a short period of time due to pressure differences in a liquid flow. Specifically, the mixture obtained in step (I) is given a flow velocity, and the liquid is passed through a throttle channel to generate fine bubbles due to cavitation, and the resulting impact force produces an aqueous phase dispersion. The flow velocity is an ultra-high pressure flow of 50 to 200 MPa. A flow velocity of less than 50 MPa is not preferred because it may result in insufficient dispersion effect.

[0029] (III) Oily Mixture Preparation Step In this step, the oil component as a dispersion medium, the (A2) component, and optional components as needed are mixed under stirring to prepare an oily mixture. In this step, it is preferable to include the (E) component as an optional component for improving dispersibility. Examples of other optional components include humectants, stabilizers, preservatives, thickeners, etc., but it is also a preferred embodiment that the mixture does not include any optional components other than the (E) component.

[0030] (IV) Oil phase dispersion step In this step, the oil mixture prepared in step (III) is homogenized based on the principle of cavitation to prepare an oil phase dispersion. The method of homogenization by cavitation is the same as in step (II).

[0031] Cosmetics can be produced using the prepared aqueous phase dispersion and, if necessary, the oil phase dispersion, according to a conventional production method.

[0032] The cosmetic according to the present invention may be an oil-in-water emulsion cosmetic, a water-in-oil emulsion cosmetic, or an unemulsified aqueous cosmetic, but is preferably an oil-in-water emulsion cosmetic or a water-in-oil emulsion cosmetic, and more preferably a water-in-oil emulsion cosmetic.

[0033] The cosmetics in this specification include not only cosmetics with enhanced ultraviolet absorbing function, basic cosmetics (foundation, base makeup, etc.), and makeup cosmetics (eye shadow, blush, etc.), but also sunscreen cosmetics (sunscreen compositions). The cosmetics according to the present invention are capable of achieving a high ultraviolet protection effect and are also excellent in feel when used, and are therefore preferably sunscreen cosmetics.

[0034] The present invention will be described in detail based on the following examples, but the present invention is not limited to these examples. Unless otherwise specified, the blending amounts are expressed in mass % based on the total amount.

[0035] [Aqueous Phase Dispersions W1 to W6] Using the compositions shown in Table 1, aqueous phase dispersions W1 to W5 were prepared by a dispersion method using cavitation, and aqueous phase dispersion W6 was prepared by a dispersion method using a homomixer. In Table 1, (*1): "STR 100C-LP", manufactured by Sakai Chemical Industry Co., Ltd., average primary particle size 15 nm.

[0036] [Oil Phase Dispersions O1 and O2] Using the compositions shown in Table 2, an aqueous phase dispersion O1 was prepared by a dispersion method using cavitation, and an aqueous phase dispersion O2 was prepared by a dispersion method using a homomixer. In Table 2, (*2): "ST-485SA", manufactured by Titan Kogyo Co., Ltd., average primary particle size 8 nm, (*3): "MSY-MZ500", manufactured by Teika Corporation, average primary particle size 25 nm.

[0037] [Average Secondary Particle Size] The average secondary particle size of the dispersion prepared above was measured by a dynamic scattering method. The results are shown in Tables 1 and 2.

[0038] [Evaluation of UV Protection Effect] The SPF values ​​of the dispersions prepared above were measured using an SPF measuring device "SPF MASTER" (Shiseido), and the UV protection effect was evaluated according to the following criteria. The results are shown in Tables 1 and 2. A: SPF of 50 or more B: SPF of 30 or more to less than 50 C: SPF less than 30

[0039] [Stability Evaluation] The appearance of the dispersion prepared above was visually observed immediately after preparation and after storage at room temperature for 10 days, and evaluated according to the following criteria. The results are shown in Tables 1 and 2. A: No precipitation or aggregation was observed, and the dispersion was extremely stable. B: No significant precipitation or aggregation was observed, and the dispersion was stable. C: Precipitation or aggregation was observed over time.

[0040] [Examples 1 to 6 and Comparative Examples 1 and 2] Using the dispersions prepared above, water-in-oil emulsion cosmetics of Examples 1 to 6 and Comparative Examples 1 and 2 were prepared according to the formulations shown in Table 3. In Table 3, (*4): "SA-SB-300", manufactured by Miyoshi Kasei Co., Ltd., average primary particle size 5 μm.

[0041] The evaluation of the UV protection effect and the stability evaluation were carried out using the cosmetics prepared in Table 3 in the same manner as the measurement method for the dispersion described above.

Claims

1. A cosmetic comprising (A1) a first hydrophobically treated powder, and (B) water, in which the (A1) component is dispersed in an aqueous phase, and the average particle size of secondary particles of the (A1) component in the aqueous phase is 150 nm or less.

2. The cosmetic preparation according to claim 1, wherein the aqueous phase further comprises (C) a polyether-modified silicone or polyoxyethylene alkyl ether having an HLB of 5 to 18.

3. The cosmetic preparation according to claim 1, further comprising (A2) a second hydrophobically treated powder, and (D) an oil component, wherein the (A2) component is dispersed in an oil phase, and the average particle size of the secondary particles of the (A2) component in the oil phase is 150 nm or less.

4. The cosmetic preparation according to claim 3, wherein the oil phase further comprises (E) glycerin modified at both ends with silicone.

5. The cosmetic according to claim 1, wherein the combined amount of components (A1) and (A2) is 30 mass% or less relative to the total amount of the cosmetic.

6. The cosmetic preparation according to claim 3, wherein the blending amount of component (A1) is 10 to 100 mass % of the combined blending amount of components (A1) and (A2).

7. The cosmetic according to claim 1, which is an oil-in-water emulsion cosmetic or a water-in-oil emulsion cosmetic.

8. The cosmetic according to claim 1, which is a sunscreen cosmetic.

9. A method for producing the cosmetic preparation according to claim 1, comprising: an aqueous mixture preparation step of mixing component (A1) and water to prepare an aqueous mixture; and an aqueous phase dispersion step of passing said aqueous mixture through a throttle passage as a high-pressure fluid at 50 to 200 MPa, and dispersing component (A1) in an aqueous phase by cavitation generated within said throttle passage.

10. The method according to claim 9, further comprising: an oil mixture preparation step of mixing the component (A2) and an oil to prepare an oil mixture; and an oil phase dispersion step of passing the oil mixture through a throttle passage as a high-pressure fluid at 50 to 200 MPa and dispersing the component (A2) in an oil phase by cavitation generated in the throttle passage.

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