JP6042165B2 - Method for producing composite powder - Google Patents

Description

The present invention relates to a method for manufacturing a composite powder surface coating treatment of the rod-shaped zinc oxide flaky substrate powder.

  In recent years, various methods have been taken to produce a wrinkle concealment effect and a feeling of bare skin, a method of correcting physical irregularities of the skin such as pores and fine lines on the bare skin by a blurring effect by diffuse reflection of spherical powder, By combining fine particles on the surface of flaky substrate powders such as talc, alumina, barium sulfate and mica, or by changing the refractive index of light by providing a titanium oxide layer and a silica layer on the surface of spherical silica particles There are methods for enhancing the light diffusion effect and improving the soft focus property (see Patent Documents 1 to 4).

Japanese Examined Patent Publication No. 2-42387 Japanese Examined Patent Publication No. 2-42388 Japanese Patent No. 3184608 Japanese Patent Laid-Open No. 2-16168

  However, the powders obtained by these methods have not been completely satisfied because they have to solve conflicting problems such as hiding and creating transparency.

  When spherical powder is used, it is difficult to uniformly disperse it in cosmetics, and if it is added in a large amount, press moldability becomes difficult. Also, the spherical powder may fall into the skin groove and conversely make pores and fine lines stand out.

  In addition, the method of surface-treating fine particles of titanium oxide on the flaky substrate powder can hide defects such as skin color and show a uniform finish, but its texture is not glossy and matte. I feel. In addition, titanium oxide has a problem that the finish such as foundation becomes pale due to a high refractive index, and a transparent feeling cannot be obtained.

  Further, as the ultraviolet shielding agent, organic ultraviolet absorbers and ultrafine inorganic powders such as titanium oxide and zinc oxide are used. However, organic UV screening agents have safety issues on the skin, and inorganic powders with UV screening ability tend to aggregate due to their small particle size, and lack transparency when applied to the skin. It is difficult to disperse uniformly. Furthermore, since the primary particle diameter of ultrafine particle titanium oxide or zinc oxide having an ultraviolet shielding ability is 100 nm or less, there is a concern about the problem of skin absorption.

  On the other hand, various methods are known for producing zinc oxide powder. In general, a production method called French method is known as a dry method. In this method, molten metal zinc is heated to about 1000 ° C. in a retort, the generated zinc vapor is oxidized with air, this is sent to an air cooling tube with a blower, cooled, and separated with a cyclone and a bag filter. It is a method of collecting. On the other hand, the German method is known as a wet method. In this method, a white basic zinc carbonate precipitate formed by adding a soda ash solution to an aqueous solution of zinc sulfate or zinc chloride is washed with water, dried, and calcined. However, zinc oxide produced by these methods has a problem that it is difficult to control the form. In addition, since treatment at a high temperature is required, there are problems in that the environment is affected and the cost of the reaction apparatus is increased.

The present invention has been made in view of the above-mentioned problems, and can be applied to the surface of a flaky substrate powder with zinc oxide whose form is controlled in a rod shape by an environment-friendly, simple and low-cost method. and so, without the rod-shaped zinc oxide powder to aggregate, while having a high ultraviolet absorptivity, it is an object that you provide a production method excellent composite powder transparency.

In order to achieve the above object, the present inventors have intensively studied and, as a result of conducting a soft solution reaction in two stages, the surface of the flaky substrate powder is coated with zinc oxide whose shape is controlled in a rod shape. The manufacturing method of the obtained composite powder was discovered.
Here, the two-step soft solution reaction is a flaky substrate in Process I using a water-soluble zinc compound, a glycol, an amine compound, and a metal salt of a metal ion having a charge of +4 or less. The surface of the powder is coated with zinc oxide whose shape is controlled to be spherical. Thereafter, in Process II, the powder obtained in Process I is used as a growth nucleus, and the powder obtained in Process I is used as a growth nucleus. Using a water-soluble zinc compound, glycol and an amine compound, a flaky substrate powder is obtained by a soft solution reaction. A composite powder whose shape is uniformly controlled on the surface of the rod is formed. Further, the composite powder obtained by the above production method may be calcined at 300 ° C. to 1500 ° C. By performing this calcining treatment, the specific surface area is controlled, and the oil absorption and crystallinity are controlled. Can do.

  Furthermore, by coating the surface of the obtained composite powder with a compound such as polysiloxane, alkylsilane compound, alkyl titanate compound, or fluorine compound, a coated composite powder having hydrophobicity or oleophobicity can be obtained. By blending the composite powder and / or the coated composite powder into the cosmetic, it is possible to provide a cosmetic that is excellent in ultraviolet shielding effect, soft focus property and feeling of use, and further has suppressed phototoxicity. Based on these findings, the present inventors have completed the present invention.

The method for producing a composite powder according to the present invention comprises
A method for producing a composite powder obtained by coating the surface of a flaky substrate powder with rod-shaped zinc oxide , characterized in that it is produced by the following two stages of processing steps.
First stage: When the ratio of zinc, glycol, amine compound, metal salt to be doped and water is 100% by mass of the whole mixture, the ratio of zinc is 0.01 to 10.0% by mass, and the ratio of glycol is 10%. -50 mass%, mixing so that the proportion of amine compound is 1-20 mass%, the proportion of metal to be doped is 0.00001-0.5 mass%, and the proportion of water is in the range of 40-80 mass%. The flaky substrate powder is added to the mixed solution so that the concentration of zinc oxide to be coated is in the range of 1 to 30% by mass, and then, for 10 minutes to 5 at 50 ° C. to 100 ° C. The surface of the flaky substrate powder is coated with fine spherical zinc oxide by performing a soft solution reaction that maintains the time .
Second stage: When the ratio of zinc, amine compound and water is 100% by mass of the whole mixture, the ratio of zinc is 0.01 to 10.0% by mass, and the ratio of amine compound is 0.01 to 10.0. A flaky substrate powder in which the mixture is mixed so that the mass percentage and the water ratio are in the range of 50 to 90 mass%, and the mixed solution is coated with the spherical zinc oxide as the core obtained in the first stage. Is added so that the zinc oxide concentration falls within the range of 5 to 80% by mass, and then a soft solution reaction is performed under a temperature condition of 50 ° C. to 100 ° C. for 10 minutes to 5 hours, and then 400 ° C. The target composite powder is obtained by firing at ˜1500 ° C.

According to the production method of the present invention, the flaky substrate powder is uniformly coated with zinc oxide whose form is controlled in a rod shape by a soft solution reaction that does not give an environmental load by performing the treatment in two stages. It is possible to control the particle diameter of the coated zinc oxide and to adjust the coating amount. Thus, without Rod shaped zinc oxide powder to aggregate, while having a high ultraviolet absorptivity, it is possible to obtain an excellent composite powder transparency.

Moreover, in the manufacturing method of this invention, since it is made to bake at 400 to 1500 degreeC after the soft solution reaction in a 2nd step, it is set so that a specific surface area may enter into the range of 1-100 m < ² > / g. It is possible to adjust and improve the crystallinity and to obtain a composite powder with controlled oil absorption.

Photographs (a) and (b) of the composite powder obtained in Production Example 1 observed with a scanning electron microscope Photographs (a) and (b) of the composite powder obtained in Production Comparative Example 1 observed with a scanning electron microscope The graph which shows the X-ray-diffraction result of the synthetic mica used as composite powder and base material of manufacture Example 1 The graph which shows the transmittance | permeability measurement result of the composite powder of manufacture Example 1, a base material, and the composite powder of manufacture comparative example 1

Next, a specific embodiment of a method for producing a composite powder according to the invention.

  In the present invention, the surface of the flaky substrate powder is coated with zinc oxide (rod-shaped zinc oxide) whose form is controlled in a rod shape. Here, the coated rod-shaped zinc oxide has a short diameter of 2 to 200 nm and a long diameter of about 50 to 2000 nm, forming a rod-shaped powder. The particle size of the rod-shaped powder can be controlled by reaction conditions. The average particle diameter of the rod-like particles of the composite powder is measured by observing with a transmission electron microscope (TEM), measuring the diameter of any 20 primary particles, and calculating the average value. Can do.

  The composite powder of the present invention is produced as follows. That is, the present invention is characterized in that the treatment is performed in two stages (Process I and Process II). In Process I, the ratio of zinc, glycol, amine compound, metal salt to be doped, and water is set to 100% by mass of the entire mixture. When the ratio of zinc is 0.01 to 10.0 mass%, the proportion of glycol is 10 to 50 mass%, the proportion of amine compound is 1 to 20 mass%, and the proportion of metal to be doped is 0.00001 to 0 Mix so that the ratio of water is within the range of 40 to 80% by mass. The flaky substrate powder is added so that the concentration of zinc oxide coated in the solution is in the range of 1 to 30% by mass. Thereafter, a soft solution reaction is performed for 10 minutes to 5 hours under a temperature condition of 50 ° C. to 100 ° C., followed by washing with water, filtration, drying, and pulverization, so that the zinc oxide that is the core of the spherical zinc oxide of the composite powder is coated. Thus obtained synthetic mica (flaky substrate powder) is obtained. In addition, you may stir during a heating reaction. Next, in Process II, when the ratio of zinc, amine compound and water is 100% by mass of the entire mixture, the ratio of zinc is 0.01 to 10.0% by mass, and the ratio of amine compound is 0.01 to 10%. Mix so that the ratio of water is within a range of 50 to 90% by mass. In the solution, synthetic mica (flaky substrate powder) coated with zinc oxide particles as a nucleus obtained in Process I is added so that the zinc oxide concentration is in the range of 5 to 80% by mass. Thereafter, a soft solution reaction is performed for 10 minutes to 5 hours under a temperature condition of 50 ° C. to 100 ° C., followed by washing with water, filtration, drying, and pulverization. Obtain a powder. In Process II, depending on the case, a metal salt of a metal ion having a charge of +4 or less may be used to dope the metal. Here, the dope means that a metal oxide is added to the zinc oxide powder in some form, and the addition state is not questioned, and a state where a part of the metal oxide enters the zinc oxide is also included. The state where zinc oxide powder is coated with a metal oxide is also included in the concept of this dope.

  As the water-soluble zinc compound, zinc nitrate, zinc sulfate, zinc acetate, zinc chloride and the like can be used.

  Examples of the glycol include ethylene glycol, propylene glycol, trimethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, , 8-octanediol, 1,10-decanediol, pinacol, diethylene glycol, triethylene glycol and other alkylene glycols, cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol Alicyclic glycols such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, 3-methyl-3-methoxybutyl Nord, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, triethylene glycol monomethyl ether, derivatives of monoethers and monoesters of glycols such as ethylene glycol monoacetate, and the like. Of these, it is particularly preferable to use ethylene glycol.

  Examples of the amine compound include ammonia, ethylamine, ethanolamine, diethylamine, diethanolamine, triethylamine, triethanolamine, hexamethylenetetramine, and the like. Among these, it is particularly preferable to use triethanolamine in Process I and hexamethylenetetramine in Process II.

  The metal salts of metal ions with a valence of 4 or less are iron nitrate, zirconium nitrate, magnesium nitrate, cobalt nitrate, nickel nitrate, aluminum nitrate, calcium nitrate, copper nitrate, chromium nitrate, manganese nitrate, calcium chloride, and chloride. Silver, chromium chloride, cobalt chloride, tin chloride, iron chloride, copper chloride, nickel chloride, magnesium chloride, aluminum sulfate, calcium sulfate, silver sulfate, tin sulfate, iron sulfate, copper sulfate, nickel sulfate, magnesium sulfate, manganese sulfate, etc. However, it is not particularly limited as long as it satisfies the condition of capturing free electrons and holes by doping a metal oxide synthesized therefrom.

  The reaction temperature in the reaction is preferably 50 ° C to 100 ° C, but the best condition is 70 ° C or higher. Moreover, you may carry out at high temperature of 100 degreeC or more by using reaction methods, such as an autoclave and a microwave hydrothermal method. However, since the reaction apparatus is expensive, it is preferable to set the reaction at 100 ° C. or lower, which allows the reaction to be performed by a generally used reaction apparatus.

  As firing conditions when firing the composite powder obtained by the above method, it is preferable to carry out in a temperature range of 300 ° C to 1500 ° C. More preferably, it is the range of 400 degreeC-800 degreeC. As a result of analysis by X-ray diffraction even when the firing temperature is less than 300 ° C., it can be confirmed that the coated rod-like zinc oxide has a crystal structure of zinc oxide, but it should be fired at 400 ° C. or higher. Thus, the crystal orientation is improved and defects such as oxygen defects in the crystal are reduced. Further, the ultraviolet ray shielding effect can also shield the ultraviolet ray from the longer wavelength side wavelength. On the other hand, when the temperature is higher than 1500 ° C., the treatment is performed at a high temperature, the load on the environment is increased, and the zinc oxide is sintered and the spherical shape cannot be maintained.

  In order to impart hydrophobicity or oleophobicity to the composite powder of the present invention, surface treatment may be performed with polysiloxane, an alkylsilane compound, an alkyl titanate compound, a fluorine compound, or the like. In addition to the above compounds, various conventionally known surface treatments can be applied. A plurality of these processes can be combined. Next, the hydrophobic and oleophobic composite powder (coating composite powder) will be described.

  In the present invention, when the composite powder is used as a foundation or sunscreen agent, water resistance and oil resistance are required after being applied to the skin. Therefore, it is necessary to impart hydrophobicity and oleophobicity to the composite powder. . In order to impart hydrophobicity to the powder, the surface of the powder is coated with a compound such as polysiloxane, an alkylsilane compound, or an alkyl titanate compound. In order to impart hydrophobicity and oleophobicity to the powder, the surface of the powder is coated with a compound such as a fluorine compound.

Examples of this surface treatment include the following treatments.
a) Fluorine compound treatment: perfluoroalkyl phosphate treatment, perfluoroalkylsilane treatment, perfluoropolyether treatment, fluorosilicone treatment, fluorinated silicone resin treatment, etc. b) Silicone treatment: methyl hydrogen polysiloxane Treatment, dimethylpolysiloxane treatment, vapor phase tetramethyltetrahydrogencyclotetrasiloxane treatment, etc. c) pendant treatment: treatment to add alkyl chain after vapor phase silicone treatment d) silane coupling agent treatment e) titanium Treatment with coupling agent f) Treatment with aluminum coupling agent g) Treatment with oil agent h) Treatment with N-acylated lysine i) Treatment with polyacrylic acid j) Treatment with metal soap ... Treatment with stearate or myristate k) Acrylic Resin treatment l) Metal oxide Management m) polysaccharide processing n) naturally occurring component processing

  In addition, as a treatment method for coating the surface of a hydrophobic compound or an oleophobic compound, the powder to be coated is stirred in an appropriate mixer, and the compound to be coated is added under a droplet or by spraying for a certain period of time. Stir vigorously at high speed. Then, the method of performing the reaction surface coating process by making it heat-ripen at 80-200 degreeC, continuing stirring is common. Alternatively, the surface coating compound is dissolved in alcohols such as ethanol, isopropyl alcohol and isobutanol, hydrocarbon organic solvents such as toluene, n-hexane and cyclohexane, polar organic solvents such as acetone, ethyl acetate and butyl acetate. In addition, after adding and stirring the cosmetic powder to the solution while stirring, the organic solvent is completely removed by evaporation, and then the surface coating treatment is performed by heating and aging at 80 to 200 ° C. It is done.

  As the mixing and dispersing method, an appropriate method can be selected according to the concentration and viscosity of the solution. Suitable examples include a method using a mixer such as a disper, a Henschel mixer, a Redige mixer, a kneader, a V-type mixer, a roll mill, a bead mill, or a twin-screw kneader, or water and powder sprayed into heated air. It is possible to select a spray drying method or the like that removes at a stroke. When pulverization is performed, a normal pulverizer such as a hammer mill, a ball mill, a sand mill, or a jet mill can be used. Since any of these pulverizers can obtain the same quality, it is not particularly limited.

  In this case, the mass ratio of the component which is a compound used for the surface coating treatment of the powder is 0.5 to 30% by mass with respect to the powder to be coated. When the mass ratio is less than 0.5% by mass, the long lasting effect and the uniform adhesion to the skin are not sufficient, and when it exceeds 30% by mass, the feel becomes very oily and moist. Not suitable for.

  Further, the form of the cosmetic to which the surface-coated composite powder (coating composite powder) of the present invention is blended is not particularly limited, but foundation, sunscreen, serum, lotion, lipstick, beauty cream, facial cleanser, perfume, Mouth fresheners, bad breath prevention agents, gargles, toothpastes, bathing agents, antiperspirants, soaps, shampoos, rinses, body soaps, body lotions, deodorants, hair creams, whitening agents, skin cleansing agents, hair restorers, etc. It is done.

  Further, in the cosmetic compounded with the composite powder of the present invention, in addition to the composite powder, oils, powders (pigments, pigments, resins), fluorine compounds, resins, surfactants used in ordinary cosmetics, Components such as a sticking agent, an antiseptic, a fragrance, a moisturizing agent, a physiologically active ingredient, a salt, a solvent, a chelating agent, a neutralizing agent, and a pH adjusting agent can be blended simultaneously. Here, examples of the powder include red 104, red 201, yellow 4, blue 1, black 401 and other dyes, yellow 4 aluminum lake, yellow 203 barium lake and other lake dyes, nylon, and the like. Powder, Silk powder, Urethane powder, Teflon powder (Teflon: registered trademark), Silicon powder, Cellulose powder, Silicone elastomer and other polymers, yellow iron oxide, red iron oxide, black iron oxide, chromium oxide, carbon black, ultramarine, Colored pigments such as bitumen, white pigments such as titanium oxide and cerium oxide, extender pigments such as talc, mica, sericite and kaolin, pearl pigments such as titanium mica, barium sulfate, calcium carbonate, magnesium carbonate, aluminum silicate, silica Metal salts such as magnesium acid, inorganic powders such as silica and boron nitride, Particles of titanium oxide, fine particles of iron oxide, alumina-treated fine titanium oxide particles, silica treated ultrafine titanium dioxide, bentonite, smectite, and the like. There are no particular restrictions on the shape and size of these powders. These powders may or may not be subjected to various conventionally known surface treatments. Examples of surface treatments include, for example, acrylic silicon treatment, methyl hydrogen polysiloxane treatment, silicone resin treatment, octyltriethoxysilane treatment, N-acylated lysine treatment, organic titanate treatment, silica treatment, alumina treatment, cellulose treatment, par Various hydrophilic, lipophilic, and water-repellent treatments such as fluoropolyether treatment and fluorinated silicone resin treatment can be used. Examples of the oil include higher alcohols such as cetyl alcohol, isostearyl alcohol, lauryl alcohol, hexadecyl alcohol, octyldodecanol, fatty acids such as isostearic acid, undecylenic acid, oleic acid, glycerin, sorbitol, ethylene glycol, propylene glycol, Polyhydric alcohols such as polyethylene glycol, myristic myristate, hexyl laurate, decyl oleate, isopropyl myristate, hexyl decyl dimethyloctanoate, glyceryl monostearate, diethyl phthalate, ethylene glycol monostearate, octyl oxystearate, etc. Esters, hydrocarbons such as liquid paraffin, petrolatum, squalane, lanolin, reduced lanolin, wax such as carnauba wax, mink , Cacao oil, coconut oil, balm kernel oil, camellia oil, sesame oil, castor oil, oils such as olive, ethylene-alpha-olefin co-oligomer, and the like. In addition, methyl hydrogen polysiloxane, dimethyl polysiloxane, methyl phenyl polysiloxane, polyether-modified organopolysiloxane, fluoroalkyl / polyoxyalkylene co-modified organopolysiloxane, alkyl-modified organopolysiloxane, fluorine-modified organopolysiloxane, amodimethicone , Silicon compounds such as amino-modified organopolysiloxane, silicon gel, acrylic silicon, trimethylsiloxysilicic acid, silicon RTV rubber, and fluorine compounds such as perfluoropolyether, fluorinated pitch, fluorocarbon, fluoroalcohol, and fluorinated silicone resin It is done. Examples of the surfactant include an anionic surfactant, a cationic surfactant, a nonionic surfactant, and a betaine surfactant. Examples of the solvent include purified water, ethanol, light liquid isoparaffin, lower alcohol, ethers, LPG, fluorocarbon, N-methylpyrrolidone, fluoroalcohol, perfluoropolyether, alternative chlorofluorocarbon, and volatile silicon.

Next, specific examples of the method for manufacturing the composite powder according to the present invention will be described with reference to the drawings. In addition, this invention is not limited to the Example described below. Hereinafter, an example of preparing the composite powder is referred to as “manufacturing example”, and an example of preparing a cosmetic using the composite powder is simply referred to as “example”.

(Production Example 1)
Process I: 0.10 g of iron nitrate nonahydrate was added and dissolved in 500 ml of a 0.05 mol · dm ⁻³ aqueous zinc nitrate solution. Further, 250 g of ethylene glycol was added, and then 31.2 g of triethanolamine was added and stirred. 11.4 g of flaky substrate powder (synthetic mica PDM-5L: manufactured by Topy Industries Co., Ltd.) was added thereto, and then heated to 90 ° C. at a rate of 2 ° C./min ⁻¹ to 90 ° C. The temperature was maintained at 90 ° C. for 1 hour after the arrival. Thereafter, washing with water, filtration and drying were performed to obtain a flaky substrate powder coated with zinc oxide as a core.

Process II: zinc nitrate aqueous solution 500ml of 0.1 mol · ^{dm -3,} and the hexamethylenetetramine 0.1 mol · ^{dm -3} 500ml added and stirred. 3.7 g of the flaky substrate powder coated with zinc oxide as a core obtained in Process I was added thereto, and then heated to 90 ° C. at a temperature increase rate of 0.4 ° C. · min ^−1. The temperature was maintained at 90 ° C. for 3 hours after reaching 90 ° C. Then, after washing with water, filtration, and drying, baking was performed at 400 ° C. for 2 hours to obtain a composite powder coated with 60% by mass of zinc oxide whose shape was controlled in a rod shape.

(Production Comparative Example 1)
As a comparison with the production examples, a one-step process was performed. Zinc nitrate aqueous solution 500ml of 0.1 mol · ^{dm -3,} and the hexamethylenetetramine 0.1 mol · ^{dm -3} 500ml added and stirred. 2.7 g of flaky substrate powder (synthetic mica PDM-5L: manufactured by Topy Industries Co., Ltd.) was added thereto, and then heated to 90 ° C. at a temperature increase rate of 0.4 ° C. · min ^−1. The temperature was maintained at 90 ° C. for 3 hours after the temperature was reached. Then, after performing water washing, filtration, and drying, baking was performed at 400 ° C. for 2 hours to obtain a composite powder coated with 60% by mass of zinc oxide as a whole.

  FIG. 1 shows photographs (a) and (b) obtained by observing the composite powder obtained in Production Example 1 with a scanning electron microscope, and FIG. Photographs (a) and (b) of the composite powder observed with a scanning electron microscope are shown. From these photographs, it can be seen that the two-step treatment uniformly coats the surface of the flaky substrate powder with zinc oxide whose shape is controlled in a rod shape.

  FIG. 3 shows the X-ray diffraction results of the composite powder obtained in Production Example 1 and the untreated flaky substrate powder. From the X-ray diffraction results, it can be seen that the spherical zinc oxide coated on the surface of the obtained composite powder has a peak specific to zinc oxide.

  The composite powder obtained in Production Example 1 and Production Comparative Example 1 and the untreated flaky substrate powder (synthetic mica PDM-5L) are 20% by mass with silicone oil (SF8417 manufactured by Toray Dow Corning Co., Ltd.). Then, the mixture was dispersed with a Hoovermarler at 100 rpm for 3 times. Thereafter, a transpore tape was applied on a 5 cm × 8 cm quartz plate, and 0.08 g of the dispersion dispersed by the above method was uniformly applied on the tape. After standing for 15 minutes, Sun Protection Factor (SPF) was measured using an SPF analyzer (UV-1000S manufactured by Labsphere). The results are shown in Table 1. In the measurement result of SPF, it was found that when Comparative Example 1 and untreated were compared, there was a high ultraviolet shielding effect.

  Next, the transmittance was measured using the dispersion used in the above measurement. For the measurement of the transmittance, the dispersion was charged in a sandwich cell having an optical path length of 0.03 mm, and the transparency was measured with a spectrophotometer. FIG. 4 shows the transmittance measurement result. As shown in FIG. 4, it can be seen that the composite powder produced in Production Example 1 has higher transparency in the visible light region as compared with Production Comparative Example 1. Further, since the spherical zinc oxide particles are uniformly coated, it can be seen that the ultraviolet shielding effect derived from the band gap of zinc oxide is high.

(Production Example 2)
The composite powder obtained in Production Example 1 was subjected to a surface coating treatment with methyl hydrogen polysiloxane.

  Into a Henschel mixer, 1000 parts by mass of the composite powder obtained in Production Example 1 was added, and then a solution in which 20.4 parts by mass of methylhydrogenpolysiloxane was dissolved in 125 parts by mass of isopropyl alcohol was dropped and mixed. Mix well. Thereafter, the interior of the Henschel mixer was heated and depressurized to remove isopropyl alcohol. The treated powder was taken out from the Henschel mixer, pulverized and heat-treated to obtain a composite powder treated with 2% by mass of the silicon compound.

(Example 1; Production of powder foundation)
A powder foundation was obtained according to the formulation in Table 2 and the following production method. In addition, the unit in a table | surface is the mass%.
Production method:
While mixing component A well with a mixer, add component B, which is uniformly heated and dissolved, and gradually mix, pulverize, pass through a mesh, and then mold into a metal pan using a mold. And got the product.

(Example 2)
W / O type liquid foundation was manufactured according to the prescription of Table 3 and the following manufacturing method. In addition, the unit of a compounding quantity is the mass%.
Production method:
Component B was mixed well using a mixer. On the other hand, Component A was heated to 80 ° C. and mixed well so as to be uniform. To this, component B was gradually added with stirring and gradually cooled to 50 ° C. Next, Component C was heated to 80 ° C. and dissolved uniformly, and then slowly cooled to 50 ° C. Component C was added to component A under stirring, further stirred well, and cooled to room temperature. The obtained solution was filled in a container to obtain a product.

(Comparative Example 1)
A product was obtained in the same manner as in Example 1 except that the silicon-treated composite powder produced in Production Example 2 was used instead of the silicon-treated composite powder in Production Comparative Example 1.

(Comparative Example 2)
A product was obtained in the same manner as in Example 2 except that the silicon-treated composite powder produced in Production Example 2 was used instead of the silicon-treated composite powder in Production Comparative Example 1.

  About each cosmetics produced by the Example and the comparative example, the sensory evaluation test regarding a usability | use_condition was implemented using 10 female panelists. The test was conducted in a questionnaire format, and each item was scored between 0 and 5 points, 0 points were bad in evaluation, 5 points were numerically evaluated as excellent, and the results were expressed as average points of all panelists. Therefore, the higher the score, the better the evaluation. The results are shown in Table 4.

  From the results shown in Table 4, both Examples 1 and 2 were superior to Comparative Examples 1 and 2 in terms of usability, makeup lasting, and skin transparency.

  According to the present invention, by performing the treatment in two steps, the zinc oxide powder forming a rod shape having a minor axis of 2 to 200 nm and a major axis of 50 to 2000 nm is uniformly treated on the surface of the flaky substrate powder. It is possible to provide a composite powder that is applied to the skin, and by blending the composite powder with a coated composite powder that is surface-coated with a hydrophobic compound, the feeling of use, transparency, and longevity when applied to the skin can be provided. Since it is possible to provide excellent cosmetics, it is suitable for makeup cosmetics such as foundations, eye shadows, cheeks, lipsticks, and sunscreen cosmetics, and has great industrial applicability. is there.

Claims (1)

A method of manufacturing a composite powder obtained by coating a surface of a flaky substrate powder with rod-shaped zinc oxide , which is manufactured by the following two-stage processing steps. .
First stage: When the ratio of zinc, glycol, amine compound, metal salt to be doped and water is 100% by mass of the whole mixture, the ratio of zinc is 0.01 to 10.0% by mass, and the ratio of glycol is 10%. -50 mass%, mixing so that the proportion of amine compound is 1-20 mass%, the proportion of metal to be doped is 0.00001-0.5 mass%, and the proportion of water is in the range of 40-80 mass%. The flaky substrate powder is added to the mixed solution so that the concentration of zinc oxide to be coated is in the range of 1 to 30% by mass, and then, for 10 minutes to 5 at 50 ° C. to 100 ° C. The surface of the flaky substrate powder is coated with fine spherical zinc oxide by performing a soft solution reaction that maintains the time .
Second stage: When the ratio of zinc, amine compound and water is 100% by mass of the whole mixture, the ratio of zinc is 0.01 to 10.0% by mass, and the ratio of amine compound is 0.01 to 10.0. A flaky substrate powder in which the mixture is mixed so that the mass percentage and the water ratio are in the range of 50 to 90 mass%, and the mixed solution is coated with the spherical zinc oxide as the core obtained in the first stage. Is added so that the zinc oxide concentration falls within the range of 5 to 80% by mass, and then a soft solution reaction is performed under a temperature condition of 50 ° C. to 100 ° C. for 10 minutes to 5 hours, and then 400 ° C. The target composite powder is obtained by firing at ˜1500 ° C.