JP5079230B2 - Whisker-like metal oxide and composite thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fine particulate whisker-formed metal oxide or hydroxide, useful as a cosmetic. <P>SOLUTION: This polymer conjugate of a metal oxide or hydroxide is produced by a production method comprising processes of reacting a metal salt with an alkali in the presence of a water soluble polymer for forming the conjugate of the metal oxide or hydroxide with the water soluble polymer, then washing out other product than the conjugate with an aqueous alcohol and then drying. The form of the fine particulate metal oxide in the fine particulate metal oxide-polymer conjugate becomes a whisker form. As the water soluble polymer, a polyacrylic acid and/or its salt, a polymethacrylic acid and/or its salt or a polyvinyl alcohol are preferable. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a whisker-like metal oxide, a composite with the polymer, a production method thereof, and a cosmetic containing the composite.

  Most of inorganic particles such as pigments are produced in an aqueous system and are inherently hydrophilic. However, inorganic particles produced by water-based reactions begin to grow from the moment they are made and cannot be extracted as ultrafine particles. In addition, in water, the particles tend to agglomerate with each other due to the polarity, making redispersibility difficult. A good dispersion. In order to facilitate the subsequent handling, once dried and powdered, the particle surface is activated, the particles are connected with a very strong cohesive force, and the redispersibility in polar water is further enhanced. It will be difficult. On the other hand, the use of inorganic particles such as pigments in water-based systems is infinitely equivalent to water-based paints, paints, cosmetics, foodstuffs, water-based inks and the like. In recent years, inorganic particles used in these applications have been required to be finer and more dispersible with the advancement and refinement of equipment and methods of use. To give an example of these applications, for example, titanium oxide and zinc oxide, which are often used as UV-cutting materials for cosmetic sunscreen agents, are essentially white powders that form a cloudy solution that is applied to the face and body. Then, since it becomes whitish, methods for making ultrafine particles and increasing transparency have been actively studied. In addition, the finer the pigment for ink jet printers, the clearer the printed image. So far, inorganic pigments were too large to be used, but inorganic pigments have recently attracted attention to increase weather resistance and have become finer. Has been actively studied. However, in the above example, a very strong crushing force is required to make inorganic particles finely dispersed in water, and a large amount of surfactant is required to suppress dispersion and subsequent reaggregation. It is. (For example, refer to Patent Document 1) In this case, there is a limit to the fineness of the particles, and the use is limited depending on the type and amount of the active agent. That is, it can be said that there has been a demand for fine metal oxide or hydroxide having excellent water dispersibility.

  On the other hand, it is known that the optical effect of a metal oxide or hydroxide as a pigment in cosmetics is not only affected by the particle size but also by the shape thereof. (For example, see Patent Document 2, Patent Document 3, Patent Document 4, and Patent Document 5) That is, it can be said that a technique for controlling the shape of a metal oxide is useful. In controlling the shape of the metal oxide or hydroxide, there is no known technique for controlling it into a fine particle whisker shape.

JP 2001-207060 A JP 2005-289932 A Japanese Patent Application Laid-Open No. 07-155731 JP 2002-146238 A JP 2005-272466 A

  The present invention has been made under such circumstances, and an object of the present invention is to provide a fine-particle whisker-like metal oxide or hydroxide useful for cosmetics. In the present invention, “fine particles” have a minor axis of 0.5 to 0.001 μm in a metal oxide or hydroxide, and such fine particles do not include a polymer portion.

In view of such a situation, the present inventors have sought for a metal oxide that is excellent in water dispersibility and whose shape can be controlled with fine particles, and as a result of earnest research efforts, in the presence of a water-soluble polymer, A metal halide is reacted with an alkali to form a complex of a metal oxide or hydroxide and a water-soluble polymer, and then a product other than the complex is washed with a hydrous alcohol and then dried. By manufacturing a metal oxide or hydroxide through the process, it was found that the shape can be controlled to be fine and whisker-like, and the present invention has been completed. That is, the present invention is as follows.
(1) In the presence of a water-soluble polymer, a zinc salt and an alkali are reacted to form a complex of zinc oxide or hydroxide and a water-soluble polymer, and then a product other than the complex is formed. washed with aqueous alcohol and then have a drying, the water-soluble polymer, wherein the polyacrylic acid and / or salts thereof, polymethacrylic acid and / or salts thereof or polyvinyl alcohol, fine particles A method for producing a zinc oxide or hydroxide / polymer composite.
(2) in the fine particle zinc oxide-polymer composite, wherein the shape of the particulate zinc oxide is whisker (whisker-like), particulate zinc oxide-polymer composite according to (1) Body manufacturing method.
(3) A composite of a water-soluble polymer and fine-particle zinc oxide or hydroxide, which is produced by the production method of (1) or (2) , wherein the zinc oxide or Is a fine particle zinc oxide or hydroxide-polymer composite, characterized in that the hydroxide is present in a whisker-like shape.
( 4 ) A step of producing fine particle zinc oxide or hydroxide / polymer composite by the method according to (1) or (2), and the fine particle zinc oxide or hydroxide / polymer A method for producing whisker-like zinc oxide , comprising a step of burning a water-soluble polymer by firing a composite at 500 to 1000 ° C. in an oxidizing atmosphere .
( 5 ) A skin external preparation containing the particulate zinc oxide or hydroxide / polymer complex according to ( 3) .
( 6 ) The external preparation for skin according to ( 5 ), which is a hydrous dosage form.
( 7 ) The skin external preparation described in ( 5 ) or ( 6 ), which is a cosmetic.

  ADVANTAGE OF THE INVENTION According to this invention, the fine particle whisker-like metal oxide thru | or hydroxide useful for cosmetics can be provided.

(1) The fine particle metal oxide or hydroxide and water-soluble polymer complex of the present invention The fine particle metal oxide or hydroxide and water-soluble polymer complex of the present invention Neutralizing salt such as chloride and other halides and nitrates in an aqueous carrier with a water-soluble base in the presence of a water-soluble polymer, and the anion residue and hydroxide ion of the metal salt Manufactured by ion exchange. Examples of the metal constituting the metal oxide or hydroxide include zinc, iron, aluminum, magnesium, titanium, barium, manganese, cerium, cobalt, calcium, cadmium, strontium, copper, chromium, zirconium, gold, Silver and the like can be exemplified, and among these, those belonging to the amphoteric metal are preferable, and zinc, aluminum and the like can be suitably exemplified. In particular, zinc is particularly preferable because of optical effects. These metal salts can be used alone or in the form of a composite metal oxide or hydroxide using two or more kinds. The water-soluble polymer is not particularly limited as long as it is transparent and soluble in water, but preferably has a carboxyl group or a salt form group. For example, a polymer or copolymer having acrylic acid or methacrylic acid as a constituent monomer and / or a salt thereof can be preferably exemplified. The “melting” means having a uniform distribution. Preferred examples of the polymer salt include alkali metal salts such as sodium salt and potassium salt. As other water-soluble polymers, for example, alginic acid and / or a salt thereof, carboxymethyl cellulose and / or a salt thereof can be preferably exemplified. The mass of the metal salt and the water-soluble polymer is such that the metal salt is converted into a metal oxide or hydroxide so that the metal oxide or hydroxide is 60% by mass or more. Preferably, it is preferably 60% to 99%, more preferably 85% to 99%. It is essential that the aqueous carrier contains water, and it is preferable to use a mixture of water and a soluble organic solvent. In general, it is known that when a small amount or a large amount of an organic solvent is mixed in a process of hydrolyzing a metal salt in an aqueous system to produce a hydroxide or oxide, the hydrolyzate of the metal salt becomes an oxide. ing. The water-soluble organic solvent used in the production method of the present invention is used for directing the hydrolyzate of the metal salt directly to the oxide, and almost any organic solvent miscible with water can be used. Examples of such organic solvents include alcohols such as methanol, ethanol and isopropanol, diols such as ethanediol, propanediol and butanediol, ketones such as acetone, furans such as tetrahydrofuran, and a molecular weight of 200 or less. And ethylene glycol monoethers such as methoxyethanol and ethoxyethanol. The mixing ratio of such a water-soluble organic solvent is generally in a range of 1: 9 to 9: 1 by weight of water: water-soluble organic solvent. After completion of the reaction, it is preferable to remove excess salt by washing with hydrous alcohol or the like. In addition, as a base for generating a metal oxide or hydroxide, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide can be preferably exemplified, and the amount of such base added is the same as that of a metal salt or the like. A slight or excessive amount is preferred. Thus, a metal oxide or a complex of a hydroxide and a water-soluble polymer obtained by reacting a water-soluble polymer, a water-soluble metal salt and a base in an aqueous carrier is centrifuged. It precipitates by performing etc. Such precipitation can be removed once or several times with an aqueous carrier containing the organic solvent to remove unnecessary reaction products. After such a treatment is performed, the precipitate is dried to obtain the fine-particle metal oxide-polymer complex of the present invention. Drying is performed by air drying for about 1 to 24 hours under heating at 30 to 100 ° C. Thus, a composite in which the water-soluble polymer and the whisker-like metal oxide or hydroxide are intertwined is obtained. Since such a complex is complexed with a water-soluble polymer, this complex alone is excellent in the effect of being uniformly dispersed in an aqueous carrier. Moreover, since it is a whisker shape, there is little whiteness in appearance and transparency is high. Since it is also excellent in UV protection effect, it is suitable as a raw material for UV protection cosmetics that do not feel white. Such a composite can be burned at 500 to 1000 ° C. in an oxidizing atmosphere to burn out the water-soluble polymer, and can be made into a whisker-like metal oxide.

(2) External preparation for skin of the present invention The external preparation for skin of the present invention is characterized by containing a composite of the metal oxide or hydroxide of the present invention and a water-soluble polymer. In the cosmetic composition of the present invention, the total content of the metal oxide or hydroxide and water-soluble polymer complex is preferably 0.1 to 30% by mass, more preferably 1 to 20% by mass. preferable. The amount varies depending on the dosage form and type of the external preparation for skin, but in the above range, the finish does not feel unnatural whiteness and exhibits an excellent UV protection effect. The skin external preparation of the present invention can be applied without particular limitation as long as it is a commonly known powder-containing skin external preparation, for example, UV protection cosmetics such as sun care milk, sun care powder, sun block, and undermake. Suitable examples include makeup cosmetics such as up, foundation, control color, and pressed powder, especially summer makeup cosmetics. As the dosage form, it can be applied to any dosage form such as a two-layer dispersion lotion dosage form, an emulsifier form, a powder dosage form or an oil dosage form. Particularly preferred dosage forms are bilayer dispersion lotion dosage forms or emulsifier forms containing an aqueous carrier.

In the external preparation for skin of the present invention, in addition to the complex of the present invention, an optional component usually used in external preparations for skin can be contained. Examples of such optional ingredients include macadamia nut oil, avocado oil, corn oil, olive oil, rapeseed oil, sesame oil, castor oil, safflower oil, cottonseed oil, jojoba oil, coconut oil, palm oil, liquid lanolin, and hardened coconut oil. Oil, wax, oils such as beeswax, molasses, hydrogenated castor oil, beeswax, candelilla wax, carnauba wax, ibotarou, lanolin, reduced lanolin, hard lanolin, jojoba wax; , Hydrocarbons such as microcrystalline wax; higher fatty acids such as oleic acid, isostearic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, undecylenic acid; cetyl alcohol, stearyl alcohol, isostearyl Higher alcohols such as alcohol, behenyl alcohol, octyldodecanol, myristyl alcohol, cetostearyl alcohol; cetyl isooctanoate, isopropyl myristate, hexyldecyl isostearate, diisopropyl adipate, di-2-ethylhexyl sebacate, cetyl lactate, malic acid Diisostearyl, di-2-ethylhexanoic acid ethylene glycol, dicaprate neopentyl glycol, di-2-heptylundecanoic acid glycerin, tri-2-ethylhexanoic acid glycerin, tri-2-ethylhexanoic acid trimethylolpropane, tri Synthetic ester oils such as trimethylolpropane isostearate and pentane erythritol tetra-2-ethylhexanoate; dimethylpolysiloxane, methylphenylpoly Linear polysiloxanes such as oxane and diphenylpolysiloxane; cyclic polysiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexanesiloxane; amino-modified polysiloxane, polyether-modified polysiloxane, alkyl-modified polysiloxane, Oil agents such as silicone oils such as modified polysiloxanes such as fluorine-modified polysiloxanes; Anionic surfactants such as fatty acid soap (sodium laurate, sodium palmitate, etc.), potassium lauryl sulfate, triethanolamine ether of alkyl sulfates; Cationic surfactants such as stearyltrimethylammonium, benzalkonium chloride, laurylamine oxide; imidazoline-based amphoteric surfactants (2-cocoyl-2-imida Zolinium hydroxide-1-carboxyethyloxy disodium salt, etc.), betaine surfactants (alkyl betaine, amide betaine, sulfobetaine, etc.), and amphoteric surfactants such as acylmethyltaurine; sorbitan fatty acid esters (sorbitan) Monostearate, sorbitan sesquioleate, etc.), glycerin fatty acids (eg, glyceryl monostearate), propylene glycol fatty acid esters (eg, propylene glycol monostearate), hardened castor oil derivatives, glycerin alkyl ethers, POE sorbitan fatty acid esters (POE sorbitan monooleate, polyoxyethylene sorbitan monostearate, etc.), POE sorbite fatty acid esters (POE-sorbitol monolaurate, etc.), POE glycerin fatty acid ester Tells (POE-glycerol monoisostearate, etc.), POE fatty acid esters (polyethylene glycol monooleate, POE distearate, etc.), POE alkyl ethers (POE2-octyldodecyl ether, etc.), POE alkylphenyl ethers (POE nonylphenyl) Ethers, etc.), Pluronic types, POE / POP alkyl ethers (POE / POP2-decyltetradecyl ether, etc.), Tetronics, POE castor oil / hardened castor oil derivatives (POE castor oil, POE hardened castor oil, etc.), Nonionic surfactants such as sucrose fatty acid ester and alkyl glucoside; polyethylene glycol, glycerin, 1,3-butylene glycol, erythritol, sorbitol, xylitol, maltitol, propylene Polyhydric alcohols such as recall, dipropylene glycol, diglycerin, isoprene glycol, 1,2-pentanediol, 2,4-hexanediol, 1,2-hexanediol, 1,2-octanediol; sodium pyrrolidonecarboxylate Moisturizing ingredients such as lactic acid and sodium lactate; powders such as mica, talc, kaolin, synthetic mica, calcium carbonate, magnesium carbonate, anhydrous silicic acid (silica), aluminum oxide, barium sulfate, etc. whose surface may be treated Body, the surface may be treated, inorganic pigments such as bengara, yellow iron oxide, black iron oxide, cobalt oxide, ultramarine, bitumen, titanium oxide, zinc oxide; surface may be treated, mica Pearl agents such as titanium, fish phosphorus foil, bismuth oxychloride; red 202 which may be raked, red Color 228, Red 226, Yellow 4, Blue 404, Yellow 5, Red 505, Red 230, Red 223, Orange 201, Red 213, Yellow 204, Yellow 203, Blue 1 No., green 201, purple 201, red 204, etc .; organic powders such as polyethylene powder, polymethyl methacrylate, nylon powder, organopolysiloxane elastomer; para-aminobenzoic acid UV absorbers; anthranils Acid UV absorbers; salicylic acid UV absorbers ; cinnamic acid UV absorbers ; benzophenone UV absorbers; sugar UV absorbers; 2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole; UV absorbers such as 4-methoxy-4′-t-butyldibenzoylmethane; lower alcohols such as ethanol and isopropanol Vitamin B such as vitamin A or a derivative thereof, vitamin B ₆ hydrochloride, vitamin B ₆ tripalmitate, vitamin B ₆ dioctanoate, vitamin B ₂ or a derivative thereof, vitamin B ₁₂ , vitamin B ₁₅ or a derivative thereof; Vitamin E such as α-tocopherol, β-tocopherol, γ-tocopherol, vitamin E acetate, vitamin D, vitamin H, pantothenic acid, pantethine, vitamins such as pyrroloquinoline quinone, etc .; antibacterial agents such as phenoxyethanol are preferred It can be illustrated. The skin external preparation of this invention can be manufactured by processing these components according to a conventional method.

  Hereinafter, the present invention will be described in more detail with reference to examples. Needless to say, the present invention is not limited to these examples.

<Production Example 1>
Zinc nitrate hexahydrate (18 g) and acrylic acid (1 g) were dissolved in a mixed solvent of methanol (134 g) and water (41 g) to obtain Liquid A. 3N Caustic soda (56 g) was gradually poured into the liquid A with stirring at room temperature, and heated immediately after the entire amount was poured. When the temperature reached 50 ° C., azobisisobutyronitrile (0.02 g) was added, and the temperature was raised as it was. Was continued at the reflux temperature for 1 hour and cooled. After cooling, decantation and filtration were repeated 3 times using 50% aqueous ethanol, and the resulting precipitate was dried at 90 ° C. for 4 hours to obtain a dried product (5.0 g). This was 95% wurtzite zinc oxide. That is, the precipitate was a composite of fine zinc oxide and acrylic acid (complex 1) in which 95% by mass was whisker-like fine zinc oxide and 5% by mass was polyacrylic acid. The zinc oxide was whiskered. The whisker had a minor axis of 0.03 μm and a major axis of 0.9 μm. A photomicrograph is shown in FIG.

<Comparative Production Example 1>
Zinc nitrate hexahydrate (18 g) and acrylic acid (1 g) were dissolved in a mixed solvent of methanol (134 g) and water (41 g) to obtain Liquid A. 3N Caustic soda (56 g) was gradually poured into the liquid A with stirring at room temperature, and heated immediately after the entire amount was poured. When the temperature reached 50 ° C., azobisisobutyronitrile (0.02 g) was added, and the temperature was raised as it was. Was continued at the reflux temperature for 1 hour and cooled. After cooling, decantation and filtration were repeated three times using water, and the resulting precipitate was dried at 90 ° C. for 4 hours to obtain a dried product (5.2 g). This was 95% wurtzite zinc oxide. That is, the precipitate was a composite of fine zinc oxide and acrylic acid (comparative composite 1) in which 95% by mass is spherical fine particle zinc oxide and 5% by mass is polyacrylic acid. The zinc oxide had a spherical shape and a particle size of 0.03 μm. A photomicrograph is shown in FIG.

  Using the composite 1 of Example 1, an ultraviolet protective cosmetic (bi-layer dispersion lotion dosage form), which is an external preparation for skin of the present invention, was prepared according to the formulation shown in Table 1 below. That is, stirring and solubilizing component (a) while heating component (a) at 80 ° C., component (b) was dispersed therein, and UV protective cosmetic 1 was obtained. In the same manner, the comparative cosmetic 1 in which the composite 1 of the UV protective cosmetic 1 was replaced with the comparative composite 1, 95% by mass of commercially available fine zinc oxide powder (average particle size = 0.03 μ catalog value) and polyacrylic Comparative cosmetic 2 substituted with 5% by mass of sodium acid was also produced in the same manner.

<Test Example 1>
Using the back of the panel, SPF (UV protection index) and PA (UV protection rank) of UV protective cosmetic 1, comparative cosmetic 1, and comparative cosmetic 2 were measured according to the Japan Cosmetic Industry Association Act. As a result, the UV protective cosmetic 1 was SPF 20.3 and PA ++, the comparative cosmetic 1 was SPF 17.5 and PA ++, and the comparative cosmetic 2 was SPF 12.4 and PA +. The effect of the composite of the present invention was confirmed.

<Test Example 2>
For the UV protective cosmetic 1, the comparative cosmetic 1, and the comparative cosmetic 2, the whiteness at the time of application was evaluated. Three 2 cm × 4 cm sites were prepared using the inner part of the forearm of the paneler, 30 mg of the sample was applied to each site, and after 5 minutes, the brightness difference with respect to the untreated site was measured with a Konica Minolta color difference meter. As a result, the ultraviolet protective cosmetic 1 was 1.26, the comparative cosmetic 1 was 2.03, and the comparative cosmetic 2 was 3.69. From this, it can be seen that the cosmetic of the present invention has an appearance that does not feel whiteness.

  Zinc chloride (9 g) and polyacrylic acid (degree of polymerization 5000) (2 g) were dissolved in a mixed solvent of ethanol (116 g) and water (91 g) to obtain Liquid A. 6N caustic soda (31 g) was gradually poured into the liquid A under stirring at room temperature, and heating was started 20 minutes after the completion of the total injection, and the mixture was maintained at the reflux temperature for 1 hour and cooled. After cooling, decantation and filtration were repeated three times using 50% aqueous ethanol, and the resulting precipitate was dried at 90 ° C. for 4 hours to obtain a complex 2 (5.3 g). This was 85% wurtzite zinc oxide. This was a whisker having a minor axis of 0.02 μm and a major axis of 1.2 μm. A photomicrograph of this is shown in FIG.

  In the same manner as in Example 2, the composite 2 was used to prepare an ultraviolet protective cosmetic 2 that is an external preparation for skin according to the present invention according to Table 2. This had an SPF of 21.1 and a PA of ++.

  Zinc chloride (9 g) and polyvinyl alcohol (polymerization degree 10000) (2 g) were dissolved in a mixed solvent of ethanol (116 g) and water (91 g) to obtain Liquid A. 6N caustic soda (31 g) was gradually poured into the liquid A under stirring at room temperature, and heating was started 20 minutes after the completion of the total injection, and the mixture was maintained at the reflux temperature for 1 hour and cooled. After cooling, decantation and filtration were repeated three times using 50% aqueous ethanol, and the resulting precipitate was dried at 90 ° C. for 4 hours to obtain a complex 3 (5.3 g). This was 85% wurtzite zinc oxide. The shape of this was a whisker having a minor axis of 0.05 μm and a major axis of 0.9 μm. A photomicrograph of this is shown in FIG.

  The present invention can be applied to cosmetics.

1 is a diagram illustrating a complex 1 of Example 1. FIG. (Drawing substitute photo) 1 is a diagram illustrating a comparative complex 1 of Example 1. FIG. (Drawing substitute photo) 3 is a diagram illustrating the composite 2 of Example 3. FIG. (Drawing substitute photo) 6 is a diagram illustrating the complex 3 of Example 4. FIG. (Drawing substitute photo)

Claims (7)

In the presence of a water-soluble polymer, a zinc salt and an alkali are reacted to form a complex of zinc oxide or hydroxide and a water-soluble polymer, and then a product other than the complex is treated with water-containing alcohol. in washing and then have a drying, the water-soluble polymer, polyacrylic acid and / or salts thereof, characterized in that it is a polymethacrylic acid and / or salts thereof or polyvinyl alcohol, fine particles of zinc oxide To produce a product or hydroxide / polymer composite. In the particulate zinc oxide-polymer composite, wherein the shape of the particulate zinc oxide is whisker (whisker-like), the production of particulate zinc oxide-polymer composite according to claim 1 Method. A composite of a water-soluble polymer and fine-particle zinc oxide or hydroxide, wherein the zinc oxide or hydroxide is produced by the production method according to claim 1 or 2. Particulate zinc oxide or hydroxide / polymer composite characterized by being present in a whisker-like shape. A step of producing a fine particle zinc oxide or hydroxide / polymer composite by the method according to claim 1, and a step of oxidizing the fine particle zinc oxide or hydroxide / polymer composite. A method for producing whisker-like zinc oxide , comprising a step of burning a water-soluble polymer by firing at 500 to 1000 ° C. in an atmosphere . A skin external preparation containing the particulate zinc oxide or hydroxide / polymer composite according to claim 3 . The external preparation for skin according to claim 5 , which is in a hydrous dosage form. The external preparation for skin according to claim 5 or 6 , which is a cosmetic.

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