Cosmetic

Abstract

To provide a cosmetic preparation having excellent sebum solidification effect.SOLUTION: A cosmetic preparation is used which includes low-aspect-ratio zinc oxide having an average aspect ratio less than 4 and high-aspect-ratio zinc oxide having an average aspect ratio of 4 or higher, wherein the content of the high-aspect-ratio zinc oxide is 1-80 mass% with respect to the sum of the high-aspect-ratio zinc oxide and the low-aspect-ratio zinc oxide.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a cosmetic containing zinc oxide.

Background Art

[0002] Sebum secreted from the skin mixes with the components of makeup cosmetics and causes makeup to come off over time. When a large amount of sebum is secreted, sebum floats on the surface of the face, causing sebum breakdown. As a countermeasure against sebum breakdown, it is known to blend a powder containing zinc oxide or the like that solidifies sebum to solidify the sebum and suppress sebum breakdown (for example, Patent Document 1).

[0003] Regarding zinc oxide blended in cosmetics, specific ranges have been studied for surface treatment, average particle diameter, specific surface area, etc. However, as far as the inventor knows, there is no report on a combination having a specific aspect ratio.

[0004] Users have a high awareness of suppressing sebum breakdown, and there is a demand for the development of cosmetics that can further suppress sebum breakdown.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] The inventors have surprisingly found that a cosmetic containing low aspect ratio zinc oxide and high aspect ratio zinc oxide, and the blending amount of the high aspect ratio zinc oxide is 1 to 80% by mass based on the total amount of the high aspect ratio zinc oxide and the low aspect ratio zinc oxide, has an excellent sebum solidifying effect and can realize a cosmetic that can suppress makeup breakdown. The present invention is based on these findings.

[0007] Accordingly, the present invention discloses a cosmetic comprising low aspect ratio zinc oxide and high aspect ratio zinc oxide.

[0008] According to the present invention, the following inventions are provided. (1) A cosmetic comprising low aspect ratio zinc oxide having an average aspect ratio of less than 4 and high aspect ratio zinc oxide having an average aspect ratio of 4 or more, wherein the blending amount of the high aspect ratio zinc oxide is 1 to 80% by mass based on the total amount of the high aspect ratio zinc oxide and the low aspect ratio zinc oxide. (2) The cosmetic according to (1), wherein the low aspect ratio zinc oxide is zinc oxide surface-treated with an alkylalkoxysilane. (3) The cosmetic according to (1) or (2), wherein the low aspect ratio zinc oxide is zinc oxide surface-treated with octyltriethoxysilane. (4) The cosmetic according to any one of (1) to (3), wherein the average particle diameter of the low aspect ratio zinc oxide is 20 to 60 nm. (5) The cosmetic according to any one of (1) to (4), wherein the average particle diameter of the low aspect ratio zinc oxide is 30 to 55 nm. (6) The cosmetic according to any one of (1) to (5), wherein the high aspect ratio zinc oxide is a plate-like crystal. (7) The cosmetic according to any one of (1) to (6), further comprising a dispersant. (8) The cosmetic according to any one of (1) to (7), which is an oil-in-water type or water-in-oil type emulsified cosmetic.

[0009] The cosmetic according to the present invention is excellent in sebum solidification effect and can suppress makeup collapse. Detailed description of the invention

[0010] The present invention relates to a cosmetic comprising low aspect ratio zinc oxide having an average aspect ratio of less than 4 (hereinafter, also simply referred to as "low aspect ratio zinc oxide") and high aspect ratio zinc oxide having an average aspect ratio of 4 or more (hereinafter, also simply referred to as "high aspect ratio zinc oxide"). In this cosmetic, the blending amount of the high aspect ratio zinc oxide is 1 to 80% by mass, preferably 1 to 60% by mass, more preferably 3 to 40% by mass, and still more preferably 10 to 30% by mass with respect to the total amount of the high aspect ratio zinc oxide and the low aspect ratio zinc oxide. By combining the low aspect ratio zinc oxide and the high aspect ratio zinc oxide, surprisingly, the sebum solidifying effect is remarkably improved as compared with the case of using only the low aspect ratio zinc oxide.

[0011] In the present invention, the average aspect ratio represents (average particle diameter) / (average thickness). The average particle diameter in the present invention means the average primary particle diameter, and can be obtained, for example, from the image analysis of a transmission electron microscope as the arithmetic mean of the major axis and the minor axis of the particles. The average thickness can be obtained, for example, from the image analysis of a transmission electron microscope as the arithmetic mean of the thicknesses of 20 particles. Generally, the aspect ratio of zinc oxide has a distribution. Therefore, when observing the aspect ratio distribution of zinc oxide contained in the cosmetic according to the present invention, which includes a combination of low aspect ratio zinc oxide and high aspect ratio zinc oxide, for example, by image analysis, it generally has two maxima at positions where the aspect ratio is less than 4 and at positions where the aspect ratio is 4 or more.

[0012] [Low aspect ratio zinc oxide] The cosmetic according to the present invention comprises low aspect ratio zinc oxide having an average aspect ratio of less than 4. The particle shape of the low aspect ratio zinc oxide is not particularly limited, and examples include spherical, plate-like, and crushed shapes. The average particle diameter of the low aspect ratio zinc oxide is preferably 20 to 60 nm, more preferably 30 to 55 nm.

[0013] The low aspect ratio zinc oxide is not particularly limited as long as it is hydrophobic zinc oxide generally used as a cosmetic, but it is preferably hydrophobic zinc oxide. The hydrophobic zinc oxide is formed by hydrophobizing the surface. By hydrophobizing the surface, the water resistance and dispersibility in oil are improved. As a method for hydrophobizing the surface, the surface hydrophobization treatment is preferably an alkylalkoxysilane treatment. Examples of the alkylalkoxysilane include octyltriethoxysilane and octyltrimethoxysilane, and octyltriethoxysilane treatment is preferred.

[0014] The compounding amount of the low aspect ratio zinc oxide is preferably 1 to 50% by mass, more preferably 3 to 30% by mass, based on the total amount of the cosmetic of the present invention.

[0015] [High aspect ratio zinc oxide] The cosmetic according to the present invention comprises high aspect ratio zinc oxide having an average aspect ratio of 4 or more. The particle shape of the high aspect ratio zinc oxide is preferably plate-like, more preferably hexagonal plate-like. The average particle diameter of the high aspect ratio zinc oxide is preferably 30 to 5000 nm, more preferably 50 to 4000 nm.

[0016] The high aspect ratio zinc oxide may be hydrophobic zinc oxide or non-hydrophobic zinc oxide. The hydrophobic zinc oxide is formed by hydrophobizing the surface in the same manner as described above. The non-hydrophobic zinc oxide refers to zinc oxide whose surface is not hydrophobized and is hydrophilic.

[0017] When the high aspect ratio zinc oxide is hydrophobic zinc oxide, the method for hydrophobizing the surface is not particularly limited, and examples thereof include hydrogen dimethicone treatment, dimethicone treatment, octyltriethoxysilane treatment, fatty acid dextrin treatment, perfluoroalkyl phosphate treatment, and the like.

[0018] When the cosmetic according to the present invention is an oil-in-water type or water-in-oil type emulsified cosmetic, it is preferable that both the low aspect ratio zinc oxide and the high aspect ratio zinc oxide are present in the oil phase.

[0019] [Dispersant] The cosmetic according to the present invention preferably further contains a dispersant. The dispersant is for dispersing zinc oxide in the cosmetic, and preferably disperses in the oil phase. Examples of the dispersant include isostearic acid, bisbutyldimethylconpolyglyceryl-3, and sorbitan sesquisostearate, and isostearic acid is preferable. The blending amount of the dispersant is preferably 0.1 to 5% by mass, more preferably 0.3 to 3% by mass, based on the total amount of the cosmetic.

[0020] [UV Absorbent] The cosmetic according to the present invention can contain a UV absorbent. The UV absorbent can be at least one selected from the UV absorbents conventionally used in sunscreen cosmetics.

[0021] Specific examples of the UVA absorbent include methylenebisbenzotriazolyltetramethylbutylphenol, t-butylmethoxydibenzoylmethane, diethylamino hydroxybenzoyl benzoic acid hexyl, 2-ethylhexyl dimethoxybenzylidene dioxoimidazolidine propionate, terephthalylidene dicamphor sulfonic acid, and bisethylhexyloxyphenol methoxyphenyl triazine. Specific examples of the UVB absorbent include ethylhexyl methoxycinnamate, ethylhexyl triazone, octocrylene, dimethicone diethyl benzalmalonate, polysilicone-15, oxybenzone-3, phenylbenzimidazole sulfonic acid, homosalate, droxmetrizole trisiloxane, and ethylhexyl salicylate.

[0022] [Surfactant] The cosmetic according to the present invention can contain a surfactant. Examples of the surfactant include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant.

[0023] [Metal salt] The cosmetic according to the present invention can contain a metal salt selected from the group consisting of a water-soluble aluminum compound, a water-soluble zirconium compound, and a zinc sulfonate compound. Examples of the metal salt include, for example, aluminum chloride, aluminum sulfate, chlorohydroxyaluminum, allantoin chlorohydroxyaluminum, allantoin dihydroxyaluminum, bromohydroxyaluminum, aluminum acetate, aluminum lactate, chlorohydroxyaluminum zirconium, chlorohydroxy zirconium, aluminum potassium sulfate, and zinc paraphenolsulfonate, and more preferably selected from the group consisting of chlorohydroxyaluminum or zinc paraphenolsulfonate, and preferably chlorohydroxyaluminum or zinc paraphenolsulfonate.

[0024] [Pigment] The cosmetic according to the present invention can contain a pigment. Examples of the pigment include, for example, an inorganic white pigment, an inorganic red pigment, an inorganic brown pigment, an inorganic yellow pigment, an inorganic black pigment, an inorganic purple pigment, an inorganic green pigment, an inorganic blue pigment, a pearl pigment, a metal powder pigment, an organic pigment, and a natural pigment. Specifically, talc, mica, sericite, etc. can be mentioned.

[0025] [Fine particle metal oxide] The cosmetic according to the present invention can contain fine particle oxides other than the above. Examples of the fine particle oxides include, for example, fine particle iron oxide, fine particle titanium oxide, cerium oxide, etc.

[0026] [Other powders] The cosmetic according to the present invention can contain powders other than pigments and fine particle metal oxides. Examples of the other powders include, for example, silica, starch powder, cellulose powder, etc. The blending amount of other powders is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total amount of the cosmetic. It is also an aspect of the present invention that the cosmetic according to the present invention does not contain other powders (0% by mass).

[0027] As optional components other than those described above, components commonly used in cosmetics, such as moisturizers, antioxidants, preservatives, alcohols, oil thickeners, aqueous phase thickeners, oil components such as silicone oil and ester oil, whitening agents, extracts, etc. can be mentioned.

[0028] In addition, the cosmetic according to the present invention can contain water. Preferably, the blending amount of water is 20 to 80% by mass, more preferably 30 to 60% by mass, based on the total amount of the cosmetic.

[0029] The cosmetic according to the present invention can be preferably used, for example, as a makeup cosmetic such as a makeup base, foundation, a base cosmetic, or a sunscreen cosmetic. The dosage form of the cosmetic according to the present invention is not particularly limited, but preferably, it is a water-in-oil type or oil-in-water type emulsified cosmetic, and more preferably, it is a water-in-oil type emulsified cosmetic.

[0030] The cosmetic of the present invention can be produced according to a conventional method. When the cosmetic according to the present invention is a water-in-oil type or oil-in-water type emulsified cosmetic, the emulsification method is not particularly limited.

Examples

[0031] The present invention will be specifically described based on the following examples, but the present invention is not limited to these examples. Unless otherwise specified, the content is shown as mass% based on the total amount.

[0032] [Examples 1 to 5 and Comparative Examples 1 and 2] Cosmetics of Examples 1 to 5 and Comparative Examples 1 and 2 were prepared with the formulations shown in Table 1, and the sebum solidification effect was evaluated.

Table 1

[0033] [Evaluation method of sebum solidification effect] The cosmetics of the examples and comparative examples were applied to artificial leather (“Supra-Le”, manufactured by Ideatex Japan Co., Ltd.) in an amount of 1 mg / cm 2 . After 15 minutes from the application, the gloss value at 60° was measured using a gloss meter “VG-2000” (manufactured by Nippon Denshoku Industries Co., Ltd.). Further, oleic acid was applied in an amount of 0.5 mg / cm 2 . After 30 minutes from the application of oleic acid, the gloss value was measured in the same manner. The artificial leather was left standing on a hot plate at 37°C until the measurement 30 minutes after the application of oleic acid. For each example and comparative example, the above measurement was performed 3 times, and the difference in the gloss meter (gloss value after application of oleic acid - gloss value before application of oleic acid) was calculated using the average value of the 3 times. The obtained results are shown in Table 1. When the same procedure as above was carried out except that no cosmetics were applied to the artificial leather, the difference in the gloss meter was 2.5.

[0034] From the results in Table 1, it was found that the cosmetic containing low aspect ratio zinc oxide and high aspect ratio zinc oxide has a high sebum solidification effect.

Claims

Claim 1 A cosmetic comprising low aspect ratio zinc oxide having an average aspect ratio of less than 4 and high aspect ratio zinc oxide having an average aspect ratio of 4 or more, wherein the high aspect ratio zinc oxide is non-hydrophobic, the low aspect ratio zinc oxide is zinc oxide surface-treated with an alkylalkoxysilane, the blending amount of the high aspect ratio zinc oxide is 3 to 40% by mass based on the total amount of the high aspect ratio zinc oxide and the low aspect ratio zinc oxide, and the cosmetic is an oil-in-water type or water-in-oil type emulsified cosmetic. Claim 2 The cosmetic according to claim 1, wherein the low aspect ratio zinc oxide is zinc oxide surface-treated with octyltriethoxysilane. Claim 3 The cosmetic according to claim 1 or 2, wherein the average particle diameter of the low aspect ratio zinc oxide is 20 to 60 nm. Claim 4 The cosmetic according to any one of claims 1 to 3, wherein the average particle diameter of the low aspect ratio zinc oxide is 30 to 55 nm. Claim 5 The cosmetic according to any one of claims 1 to 4, wherein the high aspect ratio zinc oxide is a plate-like crystal. Claim 6 The cosmetic according to any one of claims 1 to 5, further comprising a dispersant.

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