Zinc Oxide Particle Dispersion and Cosmetic Containing the Same

Abstract

To provide a non-silicone zinc oxide particle dispersion of high concentration with reduced environmental load, and also a non-silicone zinc oxide particle dispersion that has a high concentration but offers excellent dispersibility and stability over time.SOLUTION: A zinc oxide particle dispersion contains the following components (a)-(c): (a) a zinc oxide particle surface-treated with fatty acid of 2.3-4.0 mol% relative to zinc oxide; (b) a polyhydroxystearic acid; and (c) a non-silicone oil solution.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a zinc oxide particle dispersion and a cosmetic containing the same.

Background Art

[0002] Conventionally, titanium dioxide particles and zinc oxide particles have been used as ultraviolet scattering agents in sunscreen cosmetics and the like because of their high ultraviolet shielding properties and transparency. Since the surfaces of these powders are hydrophilic in the untreated state, there is a risk of being washed away by sweat or rain. Therefore, especially in applications such as cosmetics, it is often used after performing a water-repellent treatment on the particle surface. In general, since primary particles of fine inorganic powders tend to aggregate, they are widely used after being dispersed in a dispersion medium. In the cosmetics industry, since silicone oil has been mainly used in the formulation system, a dispersion obtained by subjecting the surface of fine inorganic powder to a silicone treatment and dispersing it in a silicone-based solvent has been often used.

[0003] However, silicone-based dispersants are designed to have a large molecular weight for dispersion stabilization, and there are problems in usability such as stickiness and poor spreading. In recent years, non-silicone-based formulations have been increasing in the market. Therefore, also in the above-mentioned dispersions, there has been a demand for non-silicone-based materials for both the water-repellent surface treatment agent and the dispersion medium of the inorganic powder.

[0004] Among the above situations, as a material using a non-silicone-based oil agent as a dispersion medium, a non-silicone dispersion of fine particle metal oxide surface-treated with trialkoxysilane has been proposed (Patent Document 1). In addition, a non-silicone dispersion of fine particle metal oxide surface-treated with alkyl titanate has been proposed (Patent Document 2).

[0005] However, the water-repellent surface treatment agents such as the above-mentioned trialkoxysilane and alkyl titanate are still not satisfactory in terms of cost and the like, and there is still room for improvement.

Prior Art Documents

Patent Document

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] In view of the above, an object of the present invention is to provide a non-silicone-based zinc oxide particle dispersion. Another object of the present invention is to provide a non-silicone-based zinc oxide particle dispersion that is excellent in dispersibility and stability over time even at a high concentration.

Means for Solving the Problems

[0008] The present invention is the following components (a) to (c): (a) Zinc oxide particles surface-treated with 2.3 to 4.0 mol% of fatty acid with respect to zinc oxide (b) Polyhydroxystearic acid (c) Non-silicone-based oil A zinc oxide particle dispersion characterized by containing the same.

[0009] It is preferable that the fatty acid in the above component (a) is at least one selected from the group consisting of stearic acid, myristic acid, and palmitic acid. It is preferable that the above component (a) is zinc oxide particles surface-treated with one or two of aluminum hydroxide and hydrous silicic acid and further surface-treated with a fatty acid.

[0010] It is preferable that the non-silicone-based oil of the above component (c) is an ester oil or a fruit oil.

[0011] The present invention also relates to a cosmetic characterized by containing the above zinc oxide particle dispersion.

Advantages of the Invention

[0012] According to the present invention, a non-silicone-based zinc oxide particle dispersion can be provided. Further, the dispersion of the present invention is excellent in dispersibility and stability over time even at a high concentration.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described in detail. The present invention relates to the following components (a) to (c): (a) Zinc oxide particles surface-treated with a fatty acid in an amount of 2.3 to 4.0 mol% based on zinc oxide (b) Polyhydroxystearic acid (c) A non-silicone-based oil and is a zinc oxide particle dispersion characterized by containing them.

[0014] In producing a dispersion substantially composed of only non-silicone-based materials, the dispersion of the present invention can produce a non-silicone dispersion of fatty acid-treated zinc oxide particles excellent in dispersibility and stability over time by surface-treating zinc oxide particles with a specific amount of fatty acid. Further, even when the zinc oxide particles in the dispersion are at a relatively high concentration, they are excellent in dispersibility and stability over time. In particular, in addition to using a non-silicone-based oil, by using a fatty acid which is a natural-derived component, a dispersion with less environmental impact can be obtained. Therefore, the dispersant of the present invention is non-silicone-based and has high stability, and is suitable for use in cosmetics.

[0015] In the present invention, zinc oxide particles, which are ultraviolet scattering agent-shielding inorganic powders, are used as the component (a). Zinc oxide is preferable in that it has high transparency and excellent ultraviolet scattering performance.

[0016] It is preferable to use zinc oxide particles having an average primary particle diameter of 100 nm or less. When the particle diameter of the zinc oxide particles exceeds 100 nm, the hiding power is large, it becomes white, and the transparency is low. The lower limit of the average primary particle diameter of the zinc oxide particles is not particularly limited, but is usually 5 nm. The average primary particle diameter of the zinc oxide particles is the average value of 200 particle diameters converted from the specific surface area value by the BET method. The primary particle diameter of the zinc oxide particles corresponds to the diameter of a sphere having the same surface area as the specific surface area determined by the BET method. That is, the particle diameter is a value obtained by the following calculation formula from the specific surface area: Sg measured by a fully automatic BET specific surface area measuring device Macsorb (manufactured by Mountech) and the true specific gravity: ρ of zinc oxide. Particle diameter (μm) = [6 / (Sg × ρ)] (Sg (m 2 / g): Specific surface area, ρ (g / cm 3 ): True specific gravity of the particles) Note that the true specific gravity of the particles: ρ is the value of the true specific gravity of zinc oxide, 5.6, which was used in the above calculation.

[0017] As the shape of the zinc oxide particles, those having any shape such as spherical, rod-shaped, needle-shaped, spindle-shaped, plate-shaped, etc. can be used. Regarding the above average primary particle diameter in the case of a shape other than spherical, in the case of rod-shaped, needle-shaped, and spindle-shaped particles, the above average particle diameter is defined as the length on the short axis side, and in the case of plate-shaped, it is the average diameter of the maximum inscribed circle of the surface.

[0018] The zinc oxide that can be used as a raw material is not particularly limited, and zinc oxide produced by known methods such as the French method and the American method can be used. In particular, it is preferable to use zinc oxide produced by the French method in terms of having few impurities. Also, zinc oxide obtained by the precursor method of heat-treating carbonates or the like is more preferable because the particles are fine.

[0019] The zinc oxide particles constituting component (a) of the present invention have a surface treatment layer formed by a fatty acid on the surface. As the water-repellent surface treatment agent, it is most desirable that it be a fatty acid with high environmental adaptability. Here, the surface treatment refers to a water-repellent treatment for reducing the affinity of the surface of the zinc oxide particles with water. Surface treatment with a material that is easily soluble in water or dispersed in water after the treatment does not fall within the scope of the "water-repellent treatment" of the present invention.

[0020] The fatty acid used in the present invention preferably has strong water repellency. A compound that forms some kind of chemical bond with the inorganic powder is preferred, but even a physically adsorbed compound can obtain a certain degree of effect. The above-mentioned fatty acid is preferably a higher fatty acid having 10 to 30 carbon atoms because it can further improve the dispersibility of titanium dioxide particles in the dispersion. Specifically, it is preferably at least one selected from saturated fatty acids such as stearic acid, myristic acid, lauric acid, palmitic acid, and unsaturated fatty acids such as oleic acid. Among these, stearic acid, myristic acid, and palmitic acid are preferred from the viewpoints of being inexpensive, having high stability due to their simple structure, and having strong water repellency. In addition, in order to use a dispersant with a smaller environmental load, it is preferable to use a plant-derived fatty acid.

[0021] The coating amount of the fatty acid is preferably such that the zinc oxide particles can be uniformly coated. Specifically, it is preferably 2.3 to 4.0 mol% based on the zinc oxide. By setting it within this range, the zinc oxide particles can be uniformly coated, water repellency can be imparted to the zinc oxide, and sufficient dispersibility and stability over time in the dispersion can be ensured. Also, by preventing the coating amount from becoming excessive, it is possible to prevent excess fatty acid from being released, resulting in poor dispersibility or foaming in the dispersion. Further, it is presumed that no increase in viscosity occurs due to the small amount of free fatty acid. The above lower limit is more preferably 2.5 mol%. The above upper limit is more preferably 3.7 mol%.

[0022] As a method for coating the surface of zinc oxide particles with a fatty acid, for example, the fatty acid and zinc oxide particles can be added and mixed in a solvent such as isopropyl alcohol or ethanol, and then dried, pulverized, etc.

[0023] In addition, the zinc oxide particles used in the present invention are preferably those having their particle surfaces coated with other inorganic compounds. That is, it is preferable that the zinc oxide particles surface-treated with other inorganic compounds are further surface-treated with a fatty acid. As the coating material, known inorganic surface treatment materials can be used. For example, one or more of oxides or hydroxides such as Al, Si, Zr, or Sn are used for coating. Previously, by surface-treating with these, the fatty acid becomes more likely to adhere to the surface of the zinc oxide particles.

[0024] In addition, since zinc ions elute from zinc oxide particles over time, when compounded in cosmetics, it may break the emulsion system, and there is also a problem that other components are denatured due to the surface catalytic activity of zinc oxide. However, when coated with an inorganic compound, the outflow of zinc ions can be suppressed, and in such applications (for example, cosmetics, etc.), those coated with an inorganic compound are preferable.

[0025] In particular, it is preferable to use those surface-treated with one or two of aluminum hydroxide and hydrous silicic acid because they are harmless to the environment and the human body and have high activity inhibition.

[0026] The coating amount of the above inorganic surface treatment material is preferably 1 to 30% by mass based on zinc oxide. Within this range, it has sufficient activity inhibition and little influence on the properties of zinc oxide. The above lower limit is more preferably 3% by mass. The above upper limit is more preferably 20% by mass.

[0027] The surface treatment method with the above inorganic surface treatment material is not particularly limited and can be carried out by well-known general methods.

[0028] In the present invention, component (a) is preferably contained in the total amount of the dispersion at a ratio of 40 to 80% by mass. In such a blending amount range, the effects of the present invention are particularly remarkable. The above lower limit is more preferably 45% by mass, and even more preferably 50% by mass.

[0029] In particular, in the present invention, even when the concentration of component (a) in the dispersion is relatively high at 45% by mass or more, the dispersibility is good, the viscosity of the dispersion is low, and the viscosity is maintained over time.

[0030] The dispersion of the present invention contains polyhydroxystearic acid as component (b). This compound functions as a dispersant, and it is preferable in that component (a) is well dispersed in the non-silicone oil agent by containing this. When polyhydroxystearic acid is used, good dispersion can be achieved even in a small amount, and it is particularly preferable in that the ultraviolet-shielding inorganic powder having a water-repellent surface treatment layer is less likely to flow with water during use.

[0031] The hydroxyl group of hydroxystearic acid is preferably bonded to the 12th carbon, the degree of polymerization of hydroxystearic acid is preferably 3 to 12, and more preferably the degree of polymerization is 4 to 8. Commercially available products include Saracos HS-6C (manufactured by Nisshin Oillio Group, Ltd.), ARLACEL P-100 (manufactured by Unichema), and the like.

[0032] The blending amount of the above polyhydroxystearic acid is preferably 0.1 to 10% by mass in the dispersion. The above lower limit is more preferably 1% by mass, and the above upper limit is even more preferably 7% by mass or less. By setting the above ratio, it is particularly preferable in that the content of the solvent increases and the compatibility with the formulation at the time of formulating cosmetics is high.

[0033] The dispersion of the present invention contains, as component (c), a non-silicone oil. The non-silicone oil is a medium for dispersing component (a) and is an oil having no polysiloxane skeleton. A liquid oil that is liquid at normal temperature (15 to 25 °C) is suitable from the viewpoint of the dispersibility of component (a). For example, ester oils, fruit oils, and other fats and oils can be mentioned. Among them, ester oils and fruit oils are suitable in that they are easy to use when used in cosmetics. Specifically, the following can be mentioned, and one or more of them can be used.

[0034] Examples of the above ester oils include ethylhexyl palmitate, isopropyl isostearate, ethyl oleate, octyldodecyl oleate, octyldodecyl myristate, distearyl malate, glyceryl tricaprylate, isooctyl isononanoate, isotridecyl isononanoate, isononyl isononanoate, ethylhexyl isononanoate, propylene glycol dicaprylate, neopentylene glycol dicaprylate, neopentylene glycol diethylhexanoate, cetyl ethylhexanoate, glyceryl tri-2-ethylhexanoate, jojoba oil, isopropyl myristate, isopropyl palmitate, isotridecyl isononanoate, polyglyceryl diisostearate, diglyceryl triisostearate, glyceryl tribehenate, dipentaerythrityl hexa(hydroxystearic acid / stearic acid / rosin acid), neopentyl glycol dioctanoate, cholesteryl isostearate, cholesteryl hydroxystearate, cholesteryl stearate, cholesteryl lanolin fatty acid, phytosteryl oleic fatty acid, N-lauroyl-L-glutamic acid di(cholesteryl·behenyl·octyldodecyl), N-lauroyl-L-glutamic acid di(phytosteryl·2-octyldodecyl), and the like.

[0035] Examples of the above fruit oils include olive fruit oil, aomoji fruit oil, ukiyo fruit oil, caraway fruit oil, pepper fruit oil, coriander fruit oil, European plum fruit oil, vanilla fruit oil, bergamot fruit oil, lemon fruit oil, and the like.

[0036] Examples of the above-mentioned other fats and oils include safflower oil, soybean oil, evening primrose oil, grape seed oil, rose hip oil, coconut oil, almond oil, sesame oil, wheat germ oil, corn oil, cottonseed oil, avocado oil, camellia oil, peony oil, castor oil, peanut oil, hazelnut oil, macadamia nut oil, meadowfoam oil, cocoa butter, shea butter, candelilla wax, palm oil, palm kernel oil, beef tallow, horse fat, mink oil, milk fat, egg yolk oil, turtle oil, beeswax, camellia oil, and the like.

[0037] The blending amount of the above-mentioned component (c) is preferably 5 to 60% by mass in the dispersion. By setting the ratio as above, it is suitable in terms of being easily miscible with oil when blended into cosmetics and the like. The above-mentioned lower limit is more preferably 10% by mass, and the above-mentioned upper limit is more preferably 55% by mass.

[0038] In addition to the above-mentioned components, preservatives, pH adjusters, pure water, etc. may be appropriately blended into the dispersion of the present invention according to the purpose.

[0039] The dispersion of the present invention preferably has an initial viscosity of 2500 mPa·s or less according to the following evaluation method. If it is within this range, the viscosity is low and bead separation after dispersion is easy. More preferably, it is 2400 mPa·s or less.

[0040] (Initial Viscosity Evaluation Method) Put 7 ml of the freshly prepared dispersion into a 9-ml screw bottle, use a B-type viscometer (manufactured by Tokyo Keiki, TVB-10), rotor No. 4, rotate at 60 rpm, and measure the viscosity (25 °C) 60 seconds after the start of rotation.

[0041] In addition, the dispersion of the present invention preferably has a viscosity after 7 days of 5000 mPa·s or less according to the following evaluation method. If it is within this range, the viscosity is not high, and it is easy to take out from containers and the like, and the handling is good. More preferably, it is 4500 mPa·s or less.

[0042] (Method for Evaluating Viscosity over Time) Put 7 ml of the freshly prepared dispersion into a 9-ml screw bottle, store it in a constant temperature bath at 40 °C for 7 days, use a B-type viscometer (TVB-10 manufactured by Tokyo Keiki) with rotor No. 4, rotate it at 60 rpm, and measure the viscosity (at 40 °C) 60 seconds after the start of rotation.

[0043] The dispersion of the present invention is not particularly limited in its production method. Specifically, for example, it can be obtained by using components (a) to (c) as raw materials and mixing and stirring them with other components.

[0044] The dispersion of the present invention is preferably an oil-based dispersion substantially free of water. Further, the content of components other than the above-described components (a) to (c) is preferably 1% by weight or less, more preferably 0.5% by weight or less. Also, it may consist only of the above-described components (a) to (c). The dispersion of the present invention can be particularly used as a raw material for manufacturing cosmetics. Therefore, in order not to cause restrictions in formulation, it is preferable to contain as few components other than the above as possible.

[0045] The zinc oxide particle dispersion of the present invention may contain inorganic particles other than zinc oxide. The inorganic particles that can be used in combination are not particularly limited, and examples thereof include titanium dioxide. In particular, when titanium dioxide is used in combination with zinc oxide, the problem of thickening is likely to become prominent. Therefore, when used in combination with titanium dioxide, the effect of the present invention becomes more prominent. When zinc oxide is used as an ultraviolet ray shielding agent in a sunscreen cosmetic, titanium dioxide particles having different ultraviolet ray shielding regions may be used in combination. In such a case as well, the present invention is useful.

[0046] In the present invention, the titanium dioxide particles used in combination are not particularly limited, but it is preferable to use titanium dioxide particles surface-treated with a fatty acid. Also, the coating amount of the fatty acid on the titanium dioxide particles is preferably 4.0 to 8.5% by mass based on the titanium dioxide particles. Examples of the fatty acid include the same fatty acids as those used for zinc oxide. Also, similar to the zinc oxide particles, those treated with aluminum hydroxide or hydrous silicic acid and then treated with a fatty acid are preferred.

[0047] The surface treatment of the titanium dioxide particles can be carried out by the same method as the treatment of the above-described zinc oxide particles.

[0048] It is preferable to use the titanium dioxide particles having an average primary particle diameter of 200 nm or less. When the particle diameter of the titanium dioxide particles exceeds 200 nm, the hiding power is large, it becomes white, and the transparency is low. The lower limit of the average primary particle diameter of the titanium dioxide particles is not particularly limited, but is usually 5 nm. The average primary particle diameter of the titanium dioxide particles is calculated as the average value of the particle diameters of 200 particles randomly selected under an electron microscope.

[0049] The shape of the titanium dioxide particles is not particularly limited, and those having any shape such as spherical, rod-shaped, needle-shaped, spindle-shaped, plate-shaped, etc. can be used. For the above-mentioned average primary particle diameter in the case of a shape other than spherical, in the case of rod-shaped, needle-shaped, or spindle-shaped particles, it is defined by the average of the lengths on the short-axis side, and in the case of plate-shaped particles, it is defined by the average of the diagonal lengths of the surface. The major axis diameter / minor axis diameter (aspect ratio) of the titanium dioxide particles is preferably 9 or less. The aspect ratio of the titanium dioxide particles is calculated as the average value of the major axis diameter / minor axis diameter of 200 particles randomly selected under an electron microscope.

[0050] When using inorganic fine particles other than zinc oxide such as titanium dioxide, the total amount of component (a) and inorganic fine particles other than zinc oxide such as titanium dioxide is preferably 40 to 70% by volume in the total amount of the zinc oxide particle dispersion. When using inorganic particles other than zinc oxide such as titanium dioxide, the inorganic particles may be blended as long as the object of the present invention is not inhibited. For example, the blending amount of inorganic particles other than zinc oxide such as titanium dioxide is preferably 2 times or less the mass of zinc oxide.

[0051] The dispersion of the present invention is preferably a non-silicone-based dispersion. Being non-silicone-based means that it does not substantially contain silicone-based materials, and preferably does not substantially contain inorganic particles surface-treated with silicone-based oils, silicone-based surfactants, or silicone-based surface treatment agents.

[0052] The dispersion of the present invention is suitably used in cosmetics. The cosmetics are not particularly limited, but can be blended into cosmetics for external use on the skin and hair, such as skin care products, hair products, makeup products, and ultraviolet protection products. Also, the form of the product is not particularly limited, and it can be applied to emulsion form, cream form, solid form, paste form, gel form, multilayer form, mousse form, spray form, etc.

[0053] The cosmetics of the present invention may use, in addition to the dispersion of the present invention, any aqueous components and oily components that can be used in the field of cosmetics. The above-mentioned aqueous components and oily components are not particularly limited, and examples include oil components, surfactants, moisturizers, higher alcohols, sequestering agents, water-soluble natural and semi-synthetic and synthetic polymers, water-soluble and oil-soluble polymers, organic ultraviolet light screening agents, various extracts, etc. Also, if necessary, various powders such as inorganic and organic pigments, various powders such as inorganic and organic clay minerals, inorganic and organic pigments treated with metal soaps or silicone, colorants such as organic dyes, and other pharmaceutical components such as preservatives, antioxidants, pigments, thickeners, emulsifying thickeners, pH adjusters, fragrances, cooling agents, antiperspirants, bactericides, skin activators, anti-inflammatory agents, whitening agents, film formers, etc. may be contained. Specifically, one or more of the following listed compounding components can be arbitrarily blended to produce the target cosmetics by a conventional method. The blending amounts of these compounding components are not particularly limited as long as the effects of the present invention are not impaired. In addition, inorganic powders of ultraviolet scattering agents such as titanium dioxide and cerium oxide may be used as long as the object of the present invention is not inhibited. The cosmetic of the present invention can be formulated as a non-silicone type, or can be formulated to contain silicone-based materials such as silicone-based oils such as methyl silicone and methyl phenyl silicone according to the purpose.

[0054] The oil component is not particularly limited, and examples thereof 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, eno oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, sinagiri oil, Japanese cedar oil, jojoba oil, germ oil, triglycerin, glyceryl trioctanoate, glyceryl triisopalmitate, cocoa butter, coconut oil, horse fat, hydrogenated coconut oil, palm oil, beef tallow, mutton tallow, hydrogenated beef tallow, palm kernel oil, lard, beef bone fat, moru kernel oil, hardened oil, beef foot fat, moru, hydrogenated castor oil, beeswax, candelilla wax, cotton wax, carnauba wax, bayberry wax, ibota wax, whale wax, montan wax, nuka wax, lanolin, kapok wax, lanolin acetate, liquid lanolin, sugarcane wax, isopropyl lanolin fatty acid, hexyl laurate, reduced lanolin, jojoba wax, hard lanolin, shellac wax, POE lanolin alcohol ether, POE lanolin alcohol acetate, POE cholesterol ether, polyethylene glycol lanolin fatty acid, POE hydrogenated lanolin alcohol ether, liquid paraffin, ozokerite, pristane, paraffin, ceresin, squalene, petrolatum, microcrystalline wax, propylene glycol dicaprate, ethylhexyl palmitate, isotridecyl isononanoate, and the like.

[0055] The surfactant is not particularly limited, and examples thereof include lipophilic nonionic surfactants, hydrophilic nonionic surfactants, and other surfactants. The lipophilic nonionic surfactant is not particularly limited. For example, sorbitan fatty acid esters such as sorbitan monooleate, sorbitan monoisostearate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan sesquioleate, sorbitan trioleate, diglycerol sorbitan penta-2-ethylhexanoate, diglycerol sorbitan tetra-2-ethylhexanoate; glycerin polyglycerin fatty acids such as monoricinoleic acid glycerin, sesqui-oleic acid glycerin, monostearic acid glycerin, α,α´-oleic acid pyroglutamic acid glycerin, glycerin monostearate malic acid; propylene glycol fatty acid esters such as propylene glycol monostearate; hydrogenated castor oil derivatives; glycerin alkyl ethers, etc. can be mentioned.

[0056] The hydrophilic nonionic surfactant is not particularly limited. For example, POE sorbitan fatty acid esters such as POE sorbitan monooleate, POE sorbitan monostearate, and POE sorbitan tetraoleate (e.g., polysorbate 60), POE sorbitol fatty acid esters such as POE sorbitol monolaurate, POE sorbitol monooleate, POE sorbitol pentaoleate, and POE sorbitol monostearate, POE glycerin fatty acid esters such as POE glycerin monostearate, POE glycerin monoisostearate, and POE glycerin triisostearate, POE fatty acid esters such as POE monooleate, POE distearate, POE dioleate, and ethylene glycol distearate, POE alkyl ethers such as POE lauryl ether, POE oleyl ether, POE stearyl ether, POE behenyl ether, POE 2-octyldodecyl ether, and POE cholestanol ether, POE alkyl phenyl ethers such as POE octyl phenyl ether, POE nonyl phenyl ether, and POE dinonyl phenyl ether, Pluronic types such as Pluronic, POE·POP alkyl ethers such as POE·POP cetyl ether, POE·POP 2-decyltetradecyl ether, POE·POP monobutyl ether, POE·POP hydrogenated lanolin, and POE·POP glycerin ether, tetra-POE·tetra-POP ethylenediamine condensates such as Tetronic, POE castor oil, POE hydrogenated castor oil, POE hydrogenated castor oil monoisostearate, POE hydrogenated castor oil triisostearate, POE hydrogenated castor oil monopyroglutamic acid monoisostearic acid diester, POE castor oil hydrogenated castor oil derivatives such as POE hydrogenated castor oil maleic acid, POE honeybee wax·lanolin derivatives such as POE sorbitol beeswax, alkanolamides such as coconut oil fatty acid diethanolamide, lauric acid monoethanolamide, and fatty acid isopropanolamide, POE propylene glycol fatty acid ester, POE alkylamine, POE fatty acid amide, sucrose fatty acid ester, POE nonyl phenyl formaldehyde condensate, alkyl ethoxydimethylamine oxide, and trioleyl phosphate can be mentioned.

[0057] As the above-mentioned other surfactant, for example, anionic surfactants such as fatty acid soap, higher alkyl sulfate ester salts, POE lauryl sulfate triethanolamine, alkyl ether sulfate ester salts, etc., alkyltrimethylammonium salts, alkylpyridinium salts, alkyl quaternary ammonium salts, alkyldimethylbenzylammonium salts, POE alkylamines, alkylamine salts, polyamine fatty acid derivatives and other cationic surfactants, and amphoteric surfactants such as imidazoline-based amphoteric surfactants and betaine-based surfactants may be blended within a range where there are no problems with stability and skin irritation.

[0058] The above-mentioned humectant is not particularly limited, and examples thereof include xylitol, sorbitol, maltitol, chondroitin sulfate, hyaluronic acid, mucoitin sulfate, calonic acid, atelocollagen, cholesteryl-12-hydroxystearate, sodium lactate, bile acid salts, dl-pyrrolidone carboxylate, short-chain soluble collagen, diglycerin (EO) PO adduct, extract of Rosa multiflora var. cathayensis, extract of Viola yedoensis, extract of Prunella vulgaris, etc.

[0059] The above-mentioned higher alcohol is not particularly limited, and examples thereof include linear alcohols such as lauryl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, myristyl alcohol, oleyl alcohol, cetostearyl alcohol, etc., monostearyl glycerin ether (batyl alcohol), 2-decyltetradecynol, lanolin alcohol, cholesterol, phytosterol, hexyl dodecanol, isostearyl alcohol, octyl dodecanol and other branched-chain alcohols.

[0060] The sequestering agent is not particularly limited, and examples thereof include 1-hydroxyethane-1,1-diphosphonic acid, tetrasodium 1-hydroxyethane-1,1-diphosphonate, sodium citrate, sodium polyphosphate, sodium metaphosphate, gluconic acid, phosphoric acid, citric acid, ascorbic acid, succinic acid, edetic acid, etc.

[0061] The above-mentioned natural water-soluble polymers are not particularly limited, and examples thereof include plant-based polymers such as gum arabic, tragacanth gum, galactan, guar gum, carob gum, karaya gum, carrageenan, pectin, agar, quince seed (marmelo), algocolloid (cassia extract), starch (rice, corn, potato, wheat), glycyrrhizic acid, etc.; microbial-based polymers such as xanthan gum, dextran, succinoglucan, pullulan, etc.; and animal-based polymers such as collagen, casein, albumin, gelatin, etc.

[0062] The semi-synthetic water-soluble polymers are not particularly limited, and examples thereof include starch-based polymers such as carboxymethyl starch, methylhydroxypropyl starch, etc.; cellulose-based polymers such as methylcellulose, nitrocellulose, ethylcellulose, methylhydroxypropyl cellulose, hydroxyethyl cellulose, sodium cellulose sulfate, hydroxypropyl cellulose, sodium carboxymethyl cellulose (CMC), crystalline cellulose, cellulose powder, etc.; and alginic acid-based polymers such as sodium alginate, propylene glycol alginate, etc.

[0063] The synthetic water-soluble polymers are not particularly limited, and examples thereof include vinyl-based polymers such as polyvinyl alcohol, polyvinyl methyl ether, polyvinyl pyrrolidone, etc.; polyoxyethylene-based polymers such as polyethylene glycol 20,000, 40,000, 60,000, etc.; polyoxyethylene polyoxypropylene copolymer-based polymers; acrylic-based polymers such as sodium polyacrylate, polyethyl acrylate, polyacrylamide, etc.; and polyethyleneimine, cationic polymers, etc.

[0064] The inorganic water-soluble polymers are not particularly limited, and examples thereof include bentonite, aluminum magnesium silicate (veegum), laponite, hectorite, anhydrous silicic acid, etc.

[0065] The organic ultraviolet light screening agent is not particularly limited. For example, benzoic acid-based ultraviolet light screening agents such as para-aminobenzoic acid (hereinafter abbreviated as PABA), PABA monoglycerin ester, N,N-dipropoxy PABA ethyl ester, N,N-diethoxy PABA ethyl ester, N,N-dimethyl PABA ethyl ester, N,N-dimethyl PABA butyl ester, etc.; anthranilic acid-based ultraviolet light screening agents such as homomenthyl-N-acetylanthranilate, etc.; salicylic acid-based ultraviolet light screening agents such as amyl salicylate, menthyl salicylate, homomenthyl salicylate, octyl salicylate, phenyl salicylate, benzyl salicylate, p-isopropanol phenyl salicylate, etc.; cinnamic acid-based ultraviolet light screening agents such as ethylhexyl p-methoxycinnamate, octyl cinnamate, ethyl-4-isopropylcinnamate, methyl-2,5-diisopropylcinnamate, ethyl-2,4-diisopropylcinnamate, methyl-2,4-diisopropylcinnamate, propyl-p-methoxycinnamate, isopropyl-p-methoxycinnamate, isoamyl-p-methoxycinnamate, 2-ethoxyethyl-p-methoxycinnamate, cyclohexyl-p-methoxycinnamate, ethyl-α-cyano-β-phenylcinnamate, 2-ethylhexyl-α-cyano-β-phenylcinnamate, glyceryl mono-2-ethylhexanoyl-diparamethoxycinnamate, etc.; benzophenone-based ultraviolet light screening agents such as 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-4'-methylbenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonate, 4-phenylbenzophenone, 2-ethylhexyl-4'-phenyl-benzophenone-2-carboxylate, 2-hydroxy-4-n-octoxybenzophenone, 4-hydroxy-3-carboxybenzophenone, etc.;3-(4'-methylbenzylidene)-d,l-camphor, 3-benzylidene-d,l-camphor, urocanic acid, ethyl urocanate, 2-phenyl-5-methylbenzoxazole, 2,2'-hydroxy-5-methylphenylbenzotriazole, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, dibenzalazine, dianisoylmethane, 4-methoxy-4'-t-butyldibenzoylmethane, 5-(3,3-dimethyl-2-norbornylidene)-3-pentan-2-one and the like can be mentioned.;

[0066] The various extraction liquids are not particularly limited. For example, Houttuynia cordata extract, Paeonia lactiflora extract, Melissa officinalis extract, Viola yedoensis extract, Glycyrrhiza glabra extract, Paeonia suffruticosa extract, Saponaria officinalis extract, Luffa cylindrica extract, Cinchona ledgeriana extract, Saxifraga stolonifera extract, Clarissa extract, Coptis japonica extract, Wikstroemia indica extract, Primula sieboldii extract, Rosa multiflora extract, Angelica gigas extract, lemon extract, Sicilian extract, aloe extract, Zingiber officinale root extract, eucalyptus extract, Thymus vulgaris extract, sage extract, thyme extract, tea extract, seaweed extract, cucumber extract, clove extract, strawberry extract, Melissa officinalis extract, carrot extract, Malus sieversii extract, peach extract, peach leaf extract, Morus alba extract, Aster ageratoides Turcz. extract, Hamamelis mollis extract, placenta extract, thymus extract, silk extract, licorice extract and the like can be mentioned.

[0067] Examples of the above various powders include shiny colored pigments such as red iron oxide, yellow iron oxide, black iron oxide, mica titanium, iron oxide-coated mica titanium, and titanium oxide-coated glass flakes, inorganic powders such as mica, talc, kaolin, sericite, titanium dioxide, and silica, and organic powders such as polyethylene powder, nylon powder, crosslinked polystyrene, cellulose powder, and silicone powder. Preferably, in order to improve functional properties and makeup durability, part or all of the powder components may be subjected to a water-repellent treatment with substances such as silicones, fluorine compounds, metal soaps, oils, acylglutamates, etc. by a known method before use.

[0068] The other pharmaceutical components are not particularly limited. For example, vitamins such as vitamin A oil, retinol, retinol palmitate, inositol, pyridoxine hydrochloride, benzyl nicotinate, nicotinamide, DL-α-tocopherol nicotinate, magnesium ascorbyl phosphate, 2-O-α-D-glucopyranosyl-L-ascorbic acid, vitamin D2 (ergocalciferol), dl-α-tocopherol, dl-α-tocopherol acetate, pantothenic acid, biotin, etc.; hormones such as estradiol, ethinyl estradiol, etc.; amino acids such as arginine, aspartic acid, cystine, cysteine, methionine, serine, leucine, tryptophan, etc.; anti-inflammatory agents such as allantoin, azulene, etc., skin-whitening agents such as arbutin, etc.; astringents such as tannic acid, etc.; cooling agents such as L-menthol, camphor, etc., and sulfur, lysozyme chloride, pyridoxine chloride, etc. can be mentioned.

[0069] The manufacturing method of the cosmetic of the present invention is not particularly limited, and it may be manufactured by a manufacturing method according to the form of the cosmetic. Specifically, for example, the dispersion of the present invention can be obtained by mixing it with other components.

Examples

[0070] Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited by these examples in any way. In the following description, unless otherwise specified, “%” and “parts” represent “mass %” and “parts by mass”.

[0071] (Production Examples 1 to 12) Zinc oxide particles with surface treatment having the composition shown in Table 1 were prepared by the following production method, and each powder was evaluated for “water repellency”, and the results are also shown in Table 1. Note that the (mol %) of the fatty acid in Table 1 is a value based on zinc oxide alone excluding Al and silicic acid.

[0072]

Table 1

[0073] (Manufacturing method) Component 2 or 3 was mixed with three times the amount (by mass) of isopropyl alcohol of each amount and dissolved by stirring with a stirrer. The solution of Component 2 or 3 and Component 1 were thoroughly mixed in a plastic bag and heat-treated at 120 °C for 16 hours in a vent dryer. The dried product was ground with a coffee mill to obtain fatty acid-treated zinc oxide particles.

[0074] (Evaluation method 1) Water repellency 50 mL of distilled water was placed in a 100 mL beaker, 1.0 g of fatty acid-treated zinc oxide particles was floated, and stirred 10 times with a spatula. The turbidity of the water was visually observed and judged according to the following evaluation criteria. 〇: No turbidity in water, transparent △: Water is slightly turbid, translucent ×: Water is white and turbid

[0075] As shown in Table 1, Production Examples 2 to 6 and 8 to 12 with a fatty acid content of 2.3 mol% or more showed excellent water repellency, while Production Examples 1 and 7 with a fatty acid content of less than 2.3 mol% had slightly turbid water, indicating insufficient water repellency.

[0076] (Examples 1 to 8 and Comparative Examples 1 to 9) Fatty acid-treated zinc oxide particle dispersions with the compositions shown in Tables 2 and 3 were prepared by the following manufacturing method. For each sample, evaluations were made on the "initial viscosity" and "viscosity over time at 40 °C", and the results are also shown in Tables 2 and 3. (Production of fatty acid-treated titanium dioxide particles used in Examples 7 and 8) 5 g of stearic acid (manufactured by Fujifilm Wako Pure Chemical Corporation) was mixed with 15 g of isopropyl alcohol and dissolved by stirring with a stirrer. The resulting solution and 100 g of fine particle titanium oxide (manufactured by Sakai Chemical Industry Co., Ltd., STR-100C, short axis particle diameter 20 nm, long axis 100 nm, 10% aluminum hydroxide) were thoroughly mixed in a plastic bag and heat-treated at 120 °C for 16 hours in a vent dryer. The dried product was pulverized with a coffee mill to obtain fatty acid-treated titanium dioxide particles (fatty acid content relative to titanium dioxide 5.6%).

[0077]

Table 2

[0078]

Table 3

[0079] (Manufacturing method) Fatty acid-treated zinc oxide particles, Component 12 or 13, and polyhydroxystearic acid were placed in a mayonnaise bottle in the ratios shown in Table 2 and Table 3 with the same amount of φ0.5 mm zirconia beads as the total amount of the above components, mixed, and then treated with a paint shaker (manufactured by Red Devil) for 30 minutes. Thereafter, the beads were separated to obtain a fatty acid-treated zinc oxide particle dispersion.

[0080] (Evaluation method 2) Initial viscosity 7 ml of the dispersion immediately after production was placed in a 9-ml screw bottle, and using rotor No. 4 with a B-type viscometer (manufactured by Tokyo Keiki, TVB-10), it was rotated at 60 rpm, and the viscosity (25 °C) 60 seconds after the start of rotation was measured.

[0081] (Evaluation Method 3) Viscosity over Time at 40°C After dispersion, 7 ml of the as-manufactured dispersion was placed in a 9-ml screw bottle and stored in a 40°C constant temperature bath for 7 days. Using a B-type viscometer (manufactured by Tokyo Keiki, TVB-10) with rotor No. 4 and rotating at 60 rpm, the viscosity (at 40°C) 60 seconds after the start of rotation was measured.

[0082] From the results of the above examples and comparative examples, in the dispersion of the present invention, even when the concentration of the surface-treated zinc oxide particles was high, the dispersibility of the surface-treated zinc oxide particles was good and it was stable over time. On the other hand, in the dispersion of the comparative example, compared with that of the example, the surface-treated zinc oxide particles were not uniformly dispersed or aggregated over time, and it was not suitable as a dispersant. Also, in the dispersion of the comparative example, there were those with a high initial viscosity and a viscosity so high that the beads could not be separated after dispersion. Or, there were those that thickened significantly over time and gelled so that the viscosity could not be measured.

Industrial Applicability

[0083] The dispersion of the present invention can be suitably used by being blended in cosmetics.

Claims

1. The following components (a) to (c): (a) Zinc oxide particles surface-treated with a fatty acid in an amount of 2.3 to 4.0 mol% based on zinc oxide (b) Polyhydroxystearic acid (c) A non-silicone oil A zinc oxide particle dispersion characterized by containing the same.

2. The zinc oxide particle dispersion according to Claim 1, wherein the fatty acid in the component (a) is at least one selected from the group consisting of stearic acid, myristic acid, and palmitic acid.

3. The zinc oxide particle dispersion according to Claim 1 or 2, wherein the component (a) is zinc oxide particles surface-treated with one or two of aluminum hydroxide and hydrous silicic acid and further surface-treated with a fatty acid.

4. The zinc oxide particle dispersion according to any one of Claims 1 to 3, wherein the non-silicone oil of the component (c) is an ester oil or a fruit oil.

5. A cosmetic characterized by containing the zinc oxide particle dispersion according to any one of Claims 1 to 4.

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