JP5954321B2 - Method for producing radial zinc oxide particles - Google Patents

Description

The present invention relates to radial zinc oxide particles, a method for producing the same, a heat dissipating filler, and a cosmetic.

Since zinc oxide particles have properties such as heat dissipation characteristics, they are known to be used as heat dissipating fillers in resin compositions, grease compositions, paint compositions, etc. used in the electrical field. Yes.

On the other hand, as the radial zinc oxide, those described in Patent Documents 1 to 3 are known. Patent Document 1 describes a method for producing a zinc oxide whisker film. Furthermore, the crystal shape of the zinc oxide film thus produced is shown, and these have a radial shape. However, since the crystal is precipitated by leaving the solution for a long time, there is a problem that the production efficiency is lowered. Furthermore, a specific production method relating to producing zinc oxide particles is not described. Moreover, the radial zinc oxide particle comprised by the hexagonal column part located in the center of particle | grains and the part grown radially around it cannot be obtained.

Patent Documents 2 and 3 describe radial zinc oxide. However, Patent Document 2 only describes use for cosmetics, and does not describe use of a heat-dissipating filler or the like. Moreover, the radial zinc oxide particle comprised by the hexagonal column part located in the center of particle | grains and the part grown radially around it cannot be obtained.

On the other hand, in the production method of Patent Document 3, a method is described in which a precipitate is precipitated by adjusting the pH of an aqueous solution in which a zinc compound and an amine compound are mixed, and zinc oxide is obtained by heating the aqueous solution. . However, by such a method, it is not possible to obtain radial zinc oxide particles composed of a hexagonal column portion located at the center of the particle and a portion grown radially around the hexagonal column portion.

JP 2004-149367 A JP 2008-254989 A JP 2008-254991 A

In view of the above, the present invention is efficient by using only radial zinc oxide particles composed of a hexagonal column portion located at the center of the particle and a portion grown radially around the particle, using only inexpensive materials in a short time and with fewer steps. It is an object of the present invention to provide a method for producing radial zinc oxide particles well, a radial zinc oxide particle produced by such a method, a heat dissipating filler comprising such a radial zinc oxide particle, and a cosmetic.

The present invention includes a step (1) of obtaining zinc hydroxide by mixing zinc acetate and aqueous ammonia, a step (2) of dissolving zinc hydroxide obtained in step (1) in aqueous ammonia, and a step (2). A step (3) of adding the zinc ammine complex aqueous solution to water heated instantaneously to 90 ° C. or higher or a hydrophilic solvent heated to 90 ° C. or higher and thermally decomposing the resulting solution. It is also a featured method of producing radial zinc oxide particles .

By the method for producing radial zinc oxide particles of the present invention, radial zinc oxide particles can be efficiently obtained using an inexpensive raw material. Furthermore, the radial zinc oxide particles obtained by such a method exhibit excellent effects when used as a heat-dissipating filler.

2 is a scanning electron micrograph of ε-zinc hydroxide particles that are precursors of radial zinc oxide particles of the present invention obtained in the process of Example 1. FIG. 2 is an X-ray diffraction spectrum of ε-zinc hydroxide particles, which are precursors of the radial zinc oxide particles of the present invention obtained in the process of Example 1. FIG. 2 is a scanning electron micrograph of the radial zinc oxide particles of the present invention obtained in Example 1. FIG. 2 is a scanning electron micrograph of the radial zinc oxide particles of the present invention obtained in Example 1 observed at a higher magnification. 2 is an X-ray diffraction spectrum of the radial zinc oxide particles of the present invention obtained in Example 1. FIG. 2 is a scanning electron micrograph of radial zinc oxide particles of the present invention obtained in Example 2. FIG. 2 is a scanning electron micrograph of the radial zinc oxide particles of the present invention obtained in Example 2 observed at a higher magnification. 3 is a scanning electron micrograph of radial zinc oxide particles of the present invention obtained in Example 3. FIG. 4 is a scanning electron micrograph of the radial zinc oxide particles of the present invention obtained in Example 3 observed at a higher magnification. 2 is a scanning electron micrograph of zinc oxide particles obtained in Comparative Example 1. 3 is an X-ray diffraction spectrum of zinc oxide particles obtained in Comparative Example 1. 4 is a scanning electron micrograph of particles obtained in Comparative Example 2. 3 is an X-ray diffraction spectrum of particles obtained in Comparative Example 2. It is a model figure of the radial zinc oxide particle obtained by this invention.

The present invention is described in detail below.
As shown in FIG. 14, the radial zinc oxide particles of the present invention are radial zinc oxide particles composed of a hexagonal column portion located at the center of the particle and a portion grown radially around the hexagonal column portion. Conventionally, there has been no radial zinc oxide particle focusing on such a shape. The present invention provides zinc oxide particles exhibiting excellent thermal conductivity, usability, etc. derived from a characteristic radial shape.

The radial zinc oxide particles of the present invention preferably have an average particle diameter of 1 to 100 μm. In the present invention, the average particle diameter is a fixed direction diameter (two parallel lines in a fixed direction across the particle) in a field of view of 1000 to 5000 times that of a scanning electron microscope (SEM, JSM-5600, manufactured by JEOL Ltd.) photograph. The particle diameter (μm) defined by the particle interval (measured in a certain direction for particles of any shape on the image), and the constant direction diameter of 100 particles in the SEM photograph was measured. The average value of the cumulative distribution is obtained. Having a particle size within the above range can sufficiently increase the thermal conductivity when used as a heat dissipation material, and can provide a smooth feel when applied to the skin as a cosmetic. It is preferable from the viewpoint that it can be performed.

The radial zinc oxide particles of the present invention have a plate-like direction of zinc oxide measured by an X-ray diffractometer; a ratio of (002) plane strength and zinc oxide columnar direction; (100) plane strength; I (002) / It is preferable that I (100) is 0.4 to 1.0. Such a parameter represents the degree of orientation of the zinc oxide particles in the plate-like direction or the columnar direction. Therefore, this value of 0.4 to 1.0 means that the zinc oxide particles are not easily oriented in a certain direction but equivalent to any direction. Among such zinc oxide particles, particularly in the case of the radial zinc oxide particles as in the present invention, for example, when a molded body is prepared by kneading with a resin, the particles are formed with a minimum occupied volume inside the molded body. Will be linked. By connecting particles with a minimum occupied volume in this way, heat conduction percolation is formed even with a smaller amount than zinc oxide particles having a spherical shape, rod shape, needle shape, plate shape, etc., and more efficient. In particular, it is particularly preferable in that heat conduction can be enhanced.

The above I (002) / I (100) shows the result of analysis by an X-ray diffractometer Ultima III (manufactured by Rigaku Corporation) having a copper tube. The intensity of (002) plane of zinc oxide in the X-ray diffraction pattern of hexagonal wurtzite zinc oxide particles; the value of I (002) divided by the intensity of (100) plane of zinc oxide; the value of I (100) Value.

Although it does not specifically limit as a manufacturing method of the radial zinc oxide particle | grains of this invention, For example, the zinc hydroxide obtained by mixing the zinc acetate and ammonia water to obtain zinc hydroxide, and the zinc hydroxide obtained by the process (1) And a step (2) in which the aqueous solution of zinc ammine complex obtained in step (2) is instantaneously pyrolyzed at 90 ° C. or higher. By such steps, radial zinc oxide particles can be easily obtained. A method for producing such radial zinc oxide particles is also one aspect of the present invention.

Step (1) in the method for producing radial zinc oxide particles of the present invention is a step of obtaining zinc hydroxide by mixing zinc acetate and aqueous ammonia. Such a method for producing zinc hydroxide can be carried out by any method known to those skilled in the art, and examples thereof include a method of mixing an aqueous zinc acetate solution and aqueous ammonia. The reaction temperature can be 5 to 100 ° C., and the reaction time can be 0.5 to 12 hours. When zinc acetate and aqueous ammonia are mixed, zinc hydroxide precipitates as a precipitate insoluble in water.

In the present invention, zinc acetate is used as a raw material to be a zinc source. As a result, orthorhombic single-phase ε-zinc hydroxide particles, which are precursors of the zinc oxide particles of the present invention, are obtained, and ε-zinc hydroxide particles having high zinc hydroxide purity are selectively obtained. A favorable result is obtained with respect to this point.

In the step (1), the concentration in the case of using an aqueous zinc acetate solution is preferably 0.1 to 2 mol / l, and more preferably 0.3 to 1.5 mol / l. Although it does not specifically limit as a density | concentration of aqueous ammonia, It is preferable that it is 0.1-16 mol / l, and it is still more preferable that it is 0.5-10 mol / l. In the said process (1), it is preferable to mix and react ammonia more than an equivalent with respect to zinc acetate.

The obtained zinc hydroxide may be subjected to the step (2) by continuing to add ammonia water as it is without stopping the reaction in the middle of being precipitated or dispersed in water. After adding an equivalent amount of aqueous ammonia, it may be subjected to a treatment such as concentration, dilution or the like, if necessary, and then subjected to step (2).

Further, the zinc hydroxide obtained by the above step (1) may be subjected to the step (2) after removing impurities by filtering and washing with water. By doing in this way, it can suppress that the impurity produced by the process (1) remains in the obtained zinc oxide particle, and the radial zinc oxide particle with high zinc oxide purity without passing through a baking process. Is more preferable in that it can be obtained. The method of performing said filtration and water washing is not specifically limited, It can carry out by a normal method.

Step (2) is a step of obtaining a zinc ammine complex aqueous solution by dissolving the zinc hydroxide obtained in the above step (1) in aqueous ammonia. When ammonia water is further added to zinc hydroxide, an aqueous solution of tetraammine zinc ions (that is, zinc ammine complex) represented by the general formula [Zn (NH ₃ ) _{4 2} ⁺ ] is obtained.

The reaction in the step (2) can be performed by, for example, adding ammonia water to zinc hydroxide from which water has been removed or zinc hydroxide dispersed in water at a concentration of 0.001 to 500 g / l. It can be carried out. By such a process, zinc hydroxide that was insoluble in water is dissolved in water, and [Zn (NH ₃ ) _{4 2} ⁺ ] is formed.

Such a reaction can be carried out by stirring at 5 to 50 ° C. for 0.1 to 12 hours. The concentration of the aqueous ammonia used is preferably 0.1 to 16 mol / l, and more preferably 0.5 to 10 mol / l. Moreover, it is preferable that the addition amount of ammonia is the amount which becomes 5 times or more as a mole number with respect to the zinc amount.

After performing the said process (2), you may adjust the density | concentration of a zinc ammine complex by performing dilution, concentration, etc. as needed. Further, impurities existing in the system may be removed by a method such as ultrafiltration.

The step (3) is a step of obtaining zinc oxide particles by thermally decomposing the zinc ammine complex [Zn (NH ₃ ) ₄ ²⁺ ] obtained in the step (2). The production of zinc oxide from tetrahydroxyzinc ions [Zn (OH) ₄ ²⁻ ] described in Patent Document 1 and the like is performed by applying a tetrahydroxyzinc ion solution on the substrate and depositing zinc oxide on the substrate surface. However, such a method can form only thin-film zinc oxide. Furthermore, since the manufacturing method of radial zinc oxide as described in Patent Documents 2 and 3 does not obtain zinc oxide particles by thermal decomposition from a zinc ammine complex, the obtained zinc oxide particles are the method of the present invention. It is different from the radial zinc oxide particles obtained by.

Compared to these conventional production methods, the production method of the radial zinc oxide particles of the present invention is preferable in that an inexpensive raw material is used.

In the step (3), the concentration of the zinc ammine complex is preferably 0.1 to 2 mol / l, more preferably 0.2 to 1 mol / l, when converted to zinc hydroxide.

Moreover, the said process (3) is a process of thermally decomposing a zinc ammine complex instantaneously at 90 degreeC or more. By causing the thermal decomposition to proceed instantaneously, the radial zinc oxide particles of the present invention having a characteristic shape can be selectively obtained. Further, by setting the thermal decomposition temperature to 90 ° C. or higher, the thermal decomposition proceeds rapidly, and the desired radial zinc oxide particles can be stably obtained in a uniform state. Instantaneous thermal decomposition refers to the thermal decomposition of a zinc ammine complex in a short time of 1 second to 10 minutes. For example, water heated to 90 ° C or higher, or ethylene glycol heated to 90 ° C or higher And a method of adding the zinc ammine complex aqueous solution to a hydrophilic solvent such as In such a method, heated water having a volume more than twice the volume of the added zinc ammine complex aqueous solution or heated ethylene glycol having a volume more than twice the volume of the added zinc ammine complex aqueous solution. By adding to a hydrophilic solvent such as the above, it is preferable in that the thermal decomposition can be carried out efficiently with almost no decrease in the temperature of the solution.

By adjusting the concentration of these zinc ammine complexes, addition time, thermal decomposition temperature, and the like, the particle diameter, particle shape, and the like of the obtained radial zinc oxide particles can be controlled.

This invention is also the radial zinc oxide particle obtained by the manufacturing method of the radial zinc oxide particle which consists of process (1)-(3) mentioned above. Such radial zinc oxide particles preferably have the above-described physical properties.

When the radial zinc oxide particles of the present invention are used as a heat dissipating filler, they may be used alone or in combination with heat dissipating fillers having different particle diameters. The heat dissipating filler that can be used in combination is not particularly limited. For example, metal oxides such as zinc oxide, magnesium oxide, titanium oxide, and aluminum oxide having other shapes, aluminum nitride, boron nitride, silicon carbide, Examples thereof include silicon nitride, titanium nitride, metal silicon, and diamond.

When the radial zinc oxide particles of the present invention are used in combination with zinc oxide particles having a smaller particle diameter and other heat dissipating fillers, more excellent heat dissipating performance can be obtained. The zinc oxide particles having a small particle diameter used in combination are preferably those having a spherical shape, a needle shape, a rod shape, a plate shape, or the like.

When using the said radial zinc oxide particle as a heat dissipation filler, it can be used as a heat dissipation resin composition mixed with resin. In this case, the resin used may be a thermoplastic resin or a thermosetting resin, and an epoxy resin, a phenol resin, a polyphenylene sulfide (PPS) resin, a polyester resin, polyamide, polyimide, polystyrene, polyethylene, Polypropylene, polyvinyl chloride, polyvinylidene chloride, fluororesin, polymethyl methacrylate, ethylene / ethyl acrylate copolymer (EEA) resin, polycarbonate, polyurethane, polyacetal, polyphenylene ether, polyetherimide, acrylonitrile-butadiene-styrene Examples of the resin include polymer (ABS) resin, liquid crystal resin (LCP), silicone resin, and acrylic resin.

The heat-dissipating resin composition of the present invention comprises: (a) a thermoforming resin composition obtained by kneading a thermoplastic resin and the radial zinc oxide particles in a molten state; and (b) a thermosetting resin. A resin composition obtained by kneading the radial zinc oxide particles and then heat-curing, (c) a resin composition for paint in which the radial zinc oxide particles are dispersed in a resin solution or dispersion. Also good.

The compounding quantity of the said radial zinc oxide particle in the heat dissipation resin composition of this invention can be arbitrarily determined according to the performance of resin composition, such as the target heat dissipation performance and the hardness of a resin composition. In order to sufficiently develop the heat dissipation performance of the radial zinc oxide particles, the radial zinc oxide particles may be contained in an amount of 10% by volume or more, more preferably 20% by volume or more based on the total solid content in the resin composition. preferable.

When the heat-dissipating resin composition of the present invention is a resin composition for thermoforming, the resin component can be freely selected depending on the application. For example, when adhering and adhering to a heat source and a heat sink, a resin having high adhesiveness and low hardness such as silicone resin or acrylic resin may be selected.

When the heat radiating resin composition of the present invention is a resin composition for paint, the resin may be curable or non-curable. The paint may be a solvent-based one containing an organic solvent or a water-based one in which a resin is dissolved or dispersed in water. Such a heat dissipating coating composition is also one aspect of the present invention.

When using the said radial zinc oxide particle as a heat dissipation filler, it can also be used as a heat dissipation grease mixed with the base oil containing mineral oil or synthetic oil. When used as such heat dissipating grease, α-olefin, diester, polyol ester, trimellitic acid ester, polyphenyl ether, alkylphenyl ether and the like can be used as synthetic oil. It can also be used as a heat dissipating grease mixed with silicone oil.

The radial zinc oxide particles may be used as a raw material for cosmetics. Since the radial zinc oxide particles are slippery and have a smooth feel, a cosmetic having an excellent usability can be obtained. Examples of the cosmetics include foundations, makeup bases, eye shadows, blushers, mascara, lipsticks, sunscreen agents, and the like. The cosmetics of the present invention can be in any form of oily cosmetics, aqueous cosmetics, O / W type cosmetics, and W / O type cosmetics. Especially, it can use especially suitably in a foundation.

The cosmetic of the present invention may be used in combination with any aqueous component or oily component that can be used in the cosmetic field, in addition to the components constituting the mixture. The aqueous component and the oil component are not particularly limited, and examples thereof include oils, surfactants, moisturizers, higher alcohols, sequestering agents, natural and synthetic polymers, water-soluble and oil-soluble polymers, UV shielding agents, Various extracts, inorganic and organic pigments, inorganic and organic clay minerals, inorganic and organic pigments treated with metal soaps or silicones, organic dyes and other colorants, preservatives, antioxidants, pigments, thickeners, pH You may contain components, such as a regulator, a fragrance | flavor, a cooling agent, an antiperspirant, a disinfectant, and a skin activator. Specifically, it is possible to produce any desired cosmetic by a conventional method by arbitrarily blending one or more of the blending ingredients listed below. The compounding amounts of these compounding components are not particularly limited as long as the effects of the present invention are not impaired.

The oil content is not particularly limited. For example, 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, flaxseed oil, safflower oil, cottonseed oil, eno oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, cinnagari oil, Japanese kiri oil, jojoba oil, germ oil, triglycerin, glycerin trioctanoate, Glycerin triisopalmitate, cocoa butter, coconut oil, horse fat, hydrogenated coconut oil, palm oil, beef tallow, sheep fat, hydrogenated beef tallow, palm kernel oil, pork tallow, beef bone oil, owl kernel oil, hydrogenated oil, cow leg Fat, Owl, Hardened castor oil, Beeswax, Candelilla wax, Cotton wax, Carnauba wax, Bayberry wax, Ibotaro, Whale wax, Montan wax, Nukarou, Norin, Kapok wax, Lanolin acetate, Liquid lanolin, Sugar cane wax, Lanolin fatty acid isopropyl, Hexyl laurate, Reduced lanolin, Jojoba wax, Hard lanolin, Shellac wax, POE lanolin alcohol ether, POE lanolin alcohol acetate, POE cholesterol ether, lanolin fatty acid polyethylene glycol POE hydrogenated lanolin alcohol ether, liquid paraffin, ozokerite, pristane, paraffin, ceresin, squalene, petrolatum, microcrystalline wax and the like.

The lipophilic nonionic surfactant is not particularly limited. For example, sorbitan monooleate, sorbitan monoisostearate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan sesquioleate, sorbitan trioleate. Sorbitan fatty acid esters such as diglycerol sorbitan penta-2-ethylhexylate, diglycerol sorbitan tetra-2-ethylhexylate, mono-cotton oil fatty acid glycerin, glyceryl monoerucate, glyceryl sesquioleate, glyceryl monostearate, α, α '-Glycerol polyglycerin fatty acids such as glyceryl oleate pyroglutamate, glyceryl monostearate malate, propylene glycol monostearate Glycol fatty acid esters, hardened castor oil derivatives, glycerin alkyl ethers and the like.

The hydrophilic nonionic surfactant is not particularly limited. For example, POE sorbitan fatty acid esters such as POE sorbitan monooleate, POE sorbitan monostearate, POE sorbitan tetraoleate, POE sorbite monolaurate, and POE sorbite mono POE sorbite fatty acid esters such as oleate, POE sorbite pentaoleate, POE sorbite monostearate, POE glycerin fatty acid esters such as POE glycerol monostearate, POE glycerol monoisostearate, POE glycerol triisostearate, POE POE fatty acid esters such as monooleate, POE distearate, POE monodiolate, ethylene glycol stearate, POE lauryl ether, POE POE alkyl ethers such as yl ether, POE stearyl ether, POE behenyl ether, POE 2 -octyldodecyl ether, POE cholestanol ether, POE alkyl phenyl ethers such as POE octyl phenyl ether, POE nonyl phenyl ether, POE dinonyl phenyl ether Pluronic type such as brulonic, POE / POP cetyl ether, POE / POP2-decyltetradecyl ether, POE / POP monobutyl ether, POE / POP hydrogenated lanolin, POE / POP alkyl ethers such as POE / POP glycerin ether, Tetronic PEO / TetraPOP ethylenediamine condensates, POE castor oil, POE hydrogenated castor oil, POE hydrogenated castor oil monoisos POE castor oil triisostearate, POE cured castor oil monopyroglutamic acid monoisostearic acid diester, POE castor oil cured castor oil derivatives such as POE cured castor oil maleic acid, POE beeswax and lanolin derivatives such as POE sorbite beeswax, Alkanolamides such as coconut oil fatty acid diethanolamide, lauric acid monoethanolamide, fatty acid isopropanolamide, POE propylene glycol fatty acid ester, POE alkylamine, POE fatty acid amide, sucrose fatty acid ester, POE nonylphenyl formaldehyde condensate, alkylethoxydimethylamine Examples thereof include oxide and trioleyl phosphate.

Examples of other surfactants include anionic surfactants such as fatty acid soaps, higher alkyl sulfates, POE lauryl sulfate triethanolamine, alkyl ether sulfates, alkyltrimethylammonium salts, alkylpyridinium salts, alkyl quaternary salts. Stabilizes cationic surfactants such as ammonium salts, alkyldimethylbenzylammonium salts, POE alkylamines, alkylamine salts, polyamine fatty acid derivatives, and amphoteric surfactants such as imidazoline-based amphoteric surfactants and betaine-based surfactants. And you may mix | blend in the range which does not have a problem in skin irritation.

The moisturizing agent is not particularly limited, and examples thereof include xylitol, sorbitol, maltitol, chondroitin sulfate, hyaluronic acid, mucoitin sulfate, caronic acid, atelocollagen, cholesteryl-12-hydroxystearate, sodium lactate, bile salt, dl- Examples include pyrrolidone carboxylate, short-chain soluble collagen, diglycerin (EO) PO adduct, Isaiyobara extract, yarrow extract, and merirot extract.

The 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, monostearyl glycerin ether (batyl alcohol), 2-decyl. Examples thereof include branched chain alcohols such as tetradecinol, lanolin alcohol, cholesterol, phytosterol, hexyldodecanol, isostearyl alcohol, octyldodecanol, and the like.

The sequestering agent is not particularly limited. For example, 1-hydroxyethane-1,1-diphosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid tetrasodium salt, sodium citrate, sodium polyphosphate, metaphosphoric acid Examples thereof include sodium, gluconic acid, phosphoric acid, citric acid, ascorbic acid, succinic acid, edetic acid and the like.

The natural water-soluble polymer is not particularly limited. For example, arabia gum, tragacanth gum, galactan, guar gum, carob gum, caraya gum, carrageenan, pectin, agar, quince seed (malmello), alge colloid (guckweed extract), starch (rice, rice, Corn, potato, wheat), plant polymers such as glycyrrhizic acid, microbial polymers such as xanthan gum, dextran, succinoglucan and pullulan, and animal polymers such as collagen, casein, albumin and gelatin. .

The semi-synthetic water-soluble polymer is not particularly limited. For example, starch-based polymers such as carboxymethyl starch and methylhydroxypropyl starch, methylcellulose, nitrocellulose, ethylcellulose, methylhydroxypropylcellulose, hydroxyethylcellulose, sodium cellulose sulfate, Examples thereof include cellulose polymers such as hydroxypropylcellulose, sodium carboxymethylcellulose (CMC), crystalline cellulose, and cellulose powder, and alginic acid polymers such as sodium alginate and propylene glycol alginate.

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

The inorganic water-soluble polymer is not particularly limited, and examples thereof include bentonite, silicate A1Mg (beegum), laponite, hectorite, and silicic anhydride.

The ultraviolet screening agent is not particularly limited. For example, paraaminobenzoic acid (hereinafter abbreviated as PABA), PABA monoglycerin ester, N, N-dipropoxy PABA ethyl ester, N, N-diethoxy PABA ethyl ester, N, N-dimethyl Benzoic acid UV screening agents such as PABA ethyl ester and N, N-dimethyl PABA butyl ester; Anthranilic acid UV screening agents such as homomenthyl-N-acetylanthranylate; Amyl salicylate, menthyl salicylate, homomenthyl salicylate, octyl salicylate , Salicylic acid UV screening agents such as phenyl salicylate, benzyl salicylate, p-isopropanol phenyl salicylate; octylcinnamate, ethyl-4-isopropylcinnamate, methyl-2,5- Isopropyl cinnamate, ethyl-2,4-diisopropyl cinnamate, methyl-2,4-diisopropyl cinnamate, 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-ethylhexa Cinnamic acid-based ultraviolet screening agents such as noyl-diparamethoxycinnamate; 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 -Benzophenone-based UV shielding agents such as phenylbenzophenone, 2-ethylhexyl-4'-phenyl-benzophenone-2-carboxylate, 2-hydroxy-4-n-octoxybenzophenone, 4-hydroxy-3-carboxybenzophenone; (4′-methylbenzylidene) -d, l-camphor, 3-benzylidene-d, l-camphor, urocanic acid, urocanic acid ethyl ester, 2-phenyl-5-methylbenzoxazole, 2,2′-hydroxy- 5-methylphenylbenzotri Sol, 2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole, 2- (2′-hydroxy-5′-methylphenylbenzotriazole), dibenzalazine, dianisoylmethane, 4-methoxy-4′- Examples thereof include t-butyldibenzoylmethane and 5- (3,3-dimethyl-2-norbornylidene) -3-pentan-2-one.

Other drug components are not particularly limited and include, for example, vitamin A oil, retinol, retinol palmitate, inosit, pyridoxine hydrochloride, benzyl nicotinate, nicotinamide, nicotinic acid DL-α-tocopherol, magnesium ascorbate phosphate, 2 Vitamins such as -O-α-D-glucopyranosyl-L-ascorbic acid, vitamin D2 (ergocaciferol), dl-α-tocopherol, dl-α-tocopherol acetate, pantothenic acid, biotin; estradiol, ethinylestradiol, etc. Hormones; amino acids such as arginine, aspartic acid, cystine, cysteine, methionine, serine, leucine and tryptophan; anti-inflammatory agents such as allantoin and azulene; whitening agents such as arbutin; astringents such as tannic acid; L Menthol, cooling agents and sulfur camphor such as, lysozyme chloride, can be mentioned pyridoxine chloride, and the like.

There are no particular limitations on the various extracts, for example, Dokudami extract, Oat extract, Merirot extract, Odorikosou extract, Licorice extract, Peonies extract, Soap extract, Loofah extract, Kina extract, Yukinoshita extract, Clara extract, Kouhone extract, Fennel Extract, Primrose Extract, Rose Extract, Giant Extract, Lemon Extract, Shikon Extract, Aloe Extract, Shobu Root Extract, Eucalyptus Extract, Horsetail Extract, Sage Extract, Thyme Extract, Tea Extract, Seaweed Extract, Cucumber Extract, Clove Extract, Raspberry Extract, Melissa Extract , Carrot extract, marronnier extract, peach extract, peach leaf extract, mulberry extract, cornflower extract, hamamelis extract, placenta extract, thymus extract, silk extract, licorice Mention may be made of a kiss, etc.

Examples of the various powders include bengara, yellow iron oxide, black iron oxide, titanium mica, iron oxide-coated mica titanium, titanium oxide-coated glass flakes and other bright colored pigments, mica, talc, kaolin, sericite, titanium dioxide, Examples thereof include inorganic powders such as silica and organic powders such as polyethylene powder, nylon powder, crosslinked polystyrene, cellulose powder, and silicone powder. Preferably, a part or all of the powder component is hydrophobized by a known method with a substance such as silicones, fluorine compounds, metal soaps, oils, acyl glutamates in order to improve sensory characteristics and cosmetic durability. Used. Moreover, you may mix and use the other zinc oxide particle which does not correspond to this invention.

The radial zinc oxide particles of the present invention are used in the fields of rubber vulcanization accelerators, paint / ink pigments, electronic parts such as ferrite and varistors, pharmaceuticals, etc. in addition to the cosmetics and heat dissipating fillers described above. be able to.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1
Zinc acetate dihydrate (manufactured by Wako Pure Chemical Industries, Ltd.) 110.86 g was dissolved in water to prepare 500 ml of an aqueous zinc acetate solution having a concentration of 1.0 mol / l as zinc acetate dihydrate. Subsequently, ammonia water (made by Wako Pure Chemical Industries, Ltd., ammonia content: 25.0 to 27.9% by weight) 163.75 g is diluted with water to give an ammonia aqueous solution 2500 ml in which the ammonia concentration becomes 1.0 mol / l. Was prepared. Subsequently, the zinc acetate aqueous solution was added to the ammonia aqueous solution and reacted at 25 ° C. for 2 hours with stirring. After the reaction, white powder was obtained by filtration, washing with water and drying. The size and form of the obtained particles were observed with a scanning electron microscope (SEM, JSM-5600, manufactured by JEOL Ltd.). The obtained electron micrograph is shown in FIG. The composition of the obtained particles was analyzed with an X-ray diffractometer Ultima III (manufactured by Rigaku Corporation). The X-ray diffraction spectrum of the obtained particles is shown in FIG. As a result of analysis, it was found that the obtained powder was orthorhombic ε-zinc hydroxide particles. Subsequently, the obtained ε-zinc hydroxide particles were dissolved in aqueous ammonia (manufactured by Wako Pure Chemical Industries, Ltd., ammonia content: 25.0 to 27.9 wt%), and the concentration as zinc hydroxide was 0.00. An aqueous zinc ammine complex solution having a concentration of 32 mol / l was prepared. Subsequently, 500 ml of water is put into a 1 liter flask, sealed, heated to 100 ° C. while refluxing and stirring, and then 100 ml of the aqueous zinc ammine complex solution is added to the water heated to 100 ° C. over 10 seconds. It was thermally decomposed instantaneously, and aged for 5 minutes while refluxing and stirring. After aging, filtration, washing with water, and drying at 110 ° C. for 12 hours, radial zinc oxide particles having an average particle size of 3.4 μm were obtained. The size and form of the obtained particles were observed with a scanning electron microscope (SEM, JSM-5600, manufactured by JEOL Ltd.). The obtained electron micrograph is shown in FIG. Moreover, the electron micrograph observed at higher magnification is shown in FIG. The composition of the obtained particles was analyzed with an X-ray diffractometer Ultima III (manufactured by Rigaku Corporation). The X-ray diffraction spectrum of the obtained particles is shown in FIG. From the results of these analyses, it was found that the obtained particles were radial zinc oxide particles composed of a hexagonal column portion located at the center of the particle and a portion grown radially around the hexagonal column portion. The evaluation results of the physical properties of the obtained particles are shown in Table 1.

(Example 2)
Zinc acetate dihydrate (manufactured by Wako Pure Chemical Industries, Ltd.) 110.86 g was dissolved in water to prepare 500 ml of an aqueous zinc acetate solution having a concentration of 1.0 mol / l as zinc acetate dihydrate. Subsequently, ammonia water (made by Wako Pure Chemical Industries, Ltd., ammonia content: 25.0 to 27.9% by weight) 163.75 g is diluted with water to give an ammonia aqueous solution 2500 ml in which the ammonia concentration becomes 1.0 mol / l. Was prepared. Subsequently, the zinc acetate aqueous solution was added to the ammonia aqueous solution and reacted at 25 ° C. for 2 hours with stirring. After the reaction, orthorhombic ε-zinc hydroxide particles were obtained by filtration, washing with water and drying. Subsequently, the obtained ε-zinc hydroxide particles were dissolved in aqueous ammonia (manufactured by Wako Pure Chemical Industries, Ltd., ammonia content: 25.0 to 27.9 wt%), and the concentration as zinc hydroxide was 0.00. An aqueous zinc ammine complex solution having a concentration of 32 mol / l was prepared. Subsequently, 500 ml of water is placed in a 1 liter flask, heated to 100 ° C. while refluxing and stirring, and then added 100 ml of the aqueous zinc ammine complex solution to the water heated to 100 ° C. for 10 seconds. The mixture was thermally decomposed and aged for 0.1 minutes with reflux and stirring. After aging, filtration, washing with water, and drying at 110 ° C. for 12 hours, radial zinc oxide particles having an average particle size of 2.0 μm were obtained. The size and form of the obtained particles were observed with a scanning electron microscope (SEM, JSM-5600, manufactured by JEOL Ltd.). The obtained electron micrograph is shown in FIG. Moreover, the electron micrograph observed at higher magnification is shown in FIG. The evaluation results of the physical properties of the obtained particles are shown in Table 1.

Example 3
Zinc acetate dihydrate (manufactured by Wako Pure Chemical Industries, Ltd.) 110.86 g was dissolved in water to prepare 500 ml of an aqueous zinc acetate solution having a concentration of 1.0 mol / l as zinc acetate dihydrate. Subsequently, ammonia water (made by Wako Pure Chemical Industries, Ltd., ammonia content: 25.0 to 27.9% by weight) 163.75 g is diluted with water to give an ammonia aqueous solution 2500 ml in which the ammonia concentration becomes 1.0 mol / l. Was prepared. Subsequently, the zinc acetate aqueous solution was added to the ammonia aqueous solution and reacted at 25 ° C. for 2 hours with stirring. After the reaction, orthorhombic ε-zinc hydroxide particles were obtained by filtration, washing with water and drying. Subsequently, the obtained ε-zinc hydroxide particles were dissolved in aqueous ammonia (manufactured by Wako Pure Chemical Industries, Ltd., ammonia content: 25.0 to 27.9 wt%), and the concentration as zinc hydroxide was 0.00. An aqueous zinc ammine complex solution having a concentration of 32 mol / l was prepared. Subsequently, 500 ml of water is placed in a 1 liter flask, heated to 100 ° C. while refluxing and stirring, and then added 100 ml of the aqueous zinc ammine complex solution to the water heated to 100 ° C. for 10 seconds. The mixture was thermally decomposed and aged for 10 minutes while refluxing and stirring. After aging, filtration, washing with water, and drying at 110 ° C. for 12 hours, radial zinc oxide particles having an average particle size of 5.0 μm were obtained. The size and form of the obtained particles were observed with a scanning electron microscope (SEM, JSM-5600, manufactured by JEOL Ltd.). The obtained electron micrograph is shown in FIG. Moreover, the electron micrograph observed at higher magnification is shown in FIG. The evaluation results of the physical properties of the obtained particles are shown in Table 1.

(Comparative Example 1)
Zinc acetate dihydrate (manufactured by Wako Pure Chemical Industries, Ltd.) 110.86 g was dissolved in water to prepare 500 ml of an aqueous zinc acetate solution having a concentration of 1.0 mol / l as zinc acetate dihydrate. Subsequently, ammonia water (made by Wako Pure Chemical Industries, Ltd., ammonia content: 25.0 to 27.9% by weight) 163.75 g is diluted with water to give an ammonia aqueous solution 2500 ml in which the ammonia concentration becomes 1.0 mol / l. Was prepared. Subsequently, the zinc acetate aqueous solution was added to the ammonia aqueous solution and reacted at 25 ° C. for 2 hours with stirring. After the reaction, orthorhombic ε-zinc hydroxide particles were obtained by filtration, washing with water and drying. Subsequently, the obtained ε-zinc hydroxide particles were dissolved in aqueous ammonia (manufactured by Wako Pure Chemical Industries, Ltd., ammonia content: 25.0 to 27.9 wt%), and the concentration as zinc hydroxide was 0.00. An aqueous zinc ammine complex solution having a concentration of 32 mol / l was prepared. Subsequently, 250 ml of the above-mentioned ammine complex aqueous solution was placed in a 1 liter flask, heated to 100 ° C. over 60 minutes while refluxing and stirring, and then aged at 100 ° C. for 180 minutes. After aging, it was filtered, washed with water, and dried at 110 ° C. for 12 hours to obtain zinc oxide particles having an average particle size of 8.3 μm. The size and form of the obtained particles were observed with a scanning electron microscope (SEM, JSM-5600, manufactured by JEOL Ltd.). The obtained electron micrograph is shown in FIG. The composition of the obtained particles was analyzed with an X-ray diffractometer Ultima III (manufactured by Rigaku Corporation). The X-ray diffraction spectrum of the obtained particles is shown in FIG. From the electron micrograph, it was found that although the obtained particles were grown radially, a hexagonal column structure was not formed at the center of the particles, and the shape and size were not uniform. Further, from the X-ray diffraction spectrum, it is in the state of zinc oxide mixed with impurities, and the zinc oxide plate-like surface; the peak intensity of the (002) plane; Since the value of (100) was large, it was found that orientation in the plate-like surface direction occurred. The evaluation results of the physical properties of the obtained particles are shown in Table 1.

(Comparative Example 2)
Zinc acetate dihydrate (manufactured by Wako Pure Chemical Industries, Ltd.) 110.86 g was dissolved in water to prepare 500 ml of an aqueous zinc acetate solution having a concentration of 1.0 mol / l as zinc acetate dihydrate. Subsequently, ammonia water (made by Wako Pure Chemical Industries, Ltd., ammonia content: 25.0 to 27.9% by weight) 163.75 g is diluted with water to give an ammonia aqueous solution 2500 ml in which the ammonia concentration becomes 1.0 mol / l. Was prepared. Subsequently, the zinc acetate aqueous solution was added to the ammonia aqueous solution and reacted at 25 ° C. for 2 hours with stirring. After the reaction, orthorhombic ε-zinc hydroxide particles were obtained by filtration, washing with water and drying. Subsequently, the obtained ε-zinc hydroxide particles were dissolved in aqueous ammonia (manufactured by Wako Pure Chemical Industries, Ltd., ammonia content: 25.0 to 27.9 wt%), and the concentration as zinc hydroxide was 0.00. An aqueous zinc ammine complex solution having a concentration of 32 mol / l was prepared. Subsequently, 250 ml of the above-mentioned ammine complex aqueous solution was placed in a 1 liter flask, heated to 60 ° C. over 36 minutes while refluxing and stirring, and then aged at 60 ° C. for 180 minutes. After aging, the mixture was filtered, washed with water, and dried at 110 ° C. for 12 hours to obtain particles having an average particle diameter of 27.6 μm. The size and form of the obtained particles were observed with a scanning electron microscope (SEM, JSM-5600, manufactured by JEOL Ltd.). The obtained electron micrograph is shown in FIG. Moreover, the set of obtained particles was analyzed with an X-ray diffractometer Ultima III (manufactured by Rigaku Corporation). The X-ray diffraction spectrum of the obtained particles is shown in FIG. From the electron micrograph, it was found that the obtained particles were nonuniform in shape and size. Further, from the X-ray diffraction spectrum, it was found that the precursor ε-zinc hydroxide remained, and the reaction did not proceed sufficiently. The evaluation results of the physical properties of the obtained particles are shown in Table 1.

(Comparative Example 3)
Zinc acetate dihydrate (manufactured by Wako Pure Chemical Industries, Ltd.) 110.86 g was dissolved in water to prepare 500 ml of an aqueous zinc acetate solution having a concentration of 1.0 mol / l as zinc acetate dihydrate. Subsequently, ammonia water (made by Wako Pure Chemical Industries, Ltd., ammonia content: 25.0 to 27.9% by weight) 163.75 g is diluted with water to give an ammonia aqueous solution 2500 ml in which the ammonia concentration becomes 1.0 mol / l. Was prepared. Subsequently, the zinc acetate aqueous solution was added to the ammonia aqueous solution and reacted at 25 ° C. for 2 hours with stirring. After the reaction, orthorhombic ε-zinc hydroxide particles were obtained by filtration, washing with water and drying. Subsequently, the obtained ε-zinc hydroxide particles were dissolved in aqueous ammonia (manufactured by Wako Pure Chemical Industries, Ltd., ammonia content: 25.0 to 27.9 wt%), and the concentration as zinc hydroxide was 0.00. An aqueous zinc ammine complex solution having a concentration of 32 mol / l was prepared. Subsequently, 500 ml of water was placed in a 1 liter flask, heated to 75 ° C. while refluxing and stirring, and then 100 ml of the aqueous zinc ammine complex solution was added to the water heated to 75 ° C. over 10 seconds, and refluxed. The mixture was aged for 5 minutes with stirring. However, crystals did not precipitate in the liquid, and the product could not be obtained.

(X-ray diffraction spectrum, composition of the obtained particles)
The spectrum of the X-ray diffraction shown in FIGS. 2, 5, 11, and 13 and the composition of the particles obtained in Table 1 were analyzed by an X-ray diffractometer Ultima III (manufactured by Rigaku Corporation) having a copper tube. Is shown. From these results, it is clear that zinc oxide was obtained for the examples. From FIG. 11, the zinc oxide particles of Comparative Example 1 are in a state in which impurities are mixed, and the zinc oxide plate-like surface; (002) plane peak intensity; I (002) is detected to be large, and I (002) / I ( From the fact that the value of 100) is large, it is clear that the orientation in the plate-like surface direction occurs. Moreover, from FIG. 13, it is clear that the zinc oxide particles of Comparative Example 2 are in a state in which the precursor ε-zinc hydroxide remains, and the thermal decomposition does not proceed sufficiently.

(Average friction coefficient)
The average friction coefficient of Table 1 is the value which measured the zinc oxide particle obtained by the said Example and comparative example with the KES-SE friction feeling tester (made by Kato Tech Co., Ltd.). As the sensor, a silicone contactor (silicone rubber friction element with unevenness assuming a human finger) was used. The smaller the average friction coefficient, the better the slip and the smoother the feel.

4, 7 and 9, it was found that the radial zinc oxide particles of the present invention had a shape composed of a hexagonal column portion located at the center of the particle and a portion grown radially around the hexagonal column portion. Moreover, since the average friction coefficient was small, it was also shown that the zinc oxide particles had a smooth feel.

The radial zinc oxide particles of the present invention can be used as a component of a heat dissipating filler, a heat dissipating resin composition, a heat dissipating grease, a heat dissipating coating composition, and a cosmetic.

Claims (1)

Step (1) for obtaining zinc hydroxide by mixing zinc acetate and aqueous ammonia, Step (2) for dissolving zinc hydroxide obtained in Step (1) in aqueous ammonia, and Step (2). A step (3) in which the zinc ammine complex aqueous solution is instantaneously heated to 90 ° C. or higher or thermally decomposed by adding the zinc ammine complex aqueous solution to a hydrophilic solvent heated to 90 ° C. or higher. A method for producing zinc oxide particles.