JP2012071996A - Method for manufacturing tabular boehmite-based and tabular alumina-based powder, tabular powder, and cosmetic containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an environmentally friendly, simple and inexpensive method for manufacturing a tabular boehmite-based and tabular alumina-based powder capable of controlling a particle diameter, an aspect ratio and a form, and to provide a tabular powder having hydrophobicity and cosmetics having excellent feeling of use that are blended with the tabular powder.SOLUTION: In the production of tabular boehmite having a polygonal plate surface, a mean particle diameter between 1 μm and 30 μm and an aspect ratio (mean primary particle diameter/average thickness) between 2 and 50, a water-soluble aluminum compound is dissolved in water so that the concentration thereof is in the range of from 0.05 mol/L to 0.2 mol/L, added with sodium hydrogencarbonate and sodium carbonate so that the mole ratio of an aluminum ion and a sodium ion is in between 1:2 and 1:10, and is subjected to hydrothermal reaction for 1-30 hours under the condition of from 180°C to 300°C.

Description

  The present invention relates to a plate-like boehmite and a method for producing a plate-like alumina powder, a plate-like powder obtained by coating a plate-like boehmite or a plate-like alumina powder with a hydrophobic compound, and the plate-like powder. It relates to cosmetics to be contained.

In recent years, plate-like aluminum-based powders have been applied to make-up cosmetics such as foundations, eye shadows, and lipsticks, to provide adhesion to the skin, slipperiness, covering power, etc., or press molding such as foundations. Used for sex control. The plate-like particles are also used for industrial applications such as fillers, and are blended for the purpose of imparting rigidity, imparting vibration damping effects, imparting surface smoothness, and the like.
As such plate-like particles used for cosmetics and fillers, particles having a uniform particle shape and particle diameter and a high aspect ratio are required.

  However, most of the plate-like particles currently used are difficult to control the particle diameter, have a wide particle size distribution, and have a non-uniform shape. Further, there is a problem that the aggregated state is not formed in a monodispersed state but a plurality of plate-like particles are overlapped, and the characteristics of the plate-like particles cannot be sufficiently exhibited. For this reason, it is required to provide plate-like particles having a high aspect ratio that can control the particle diameter and form.

  On the other hand, various methods are conventionally known for producing plate-like aluminum-based powders. Generally, a method is known in which alumina produced by a firing method is pulverized with a ball mill or the like to form fine particles. However, the plate-like alumina produced by this method has a problem that the particle shape and size are not uniform.

Moreover, although the manufacturing method (patent document 1) of the plate-like alumina using a hydrothermal synthesis method is known, in this method, it is difficult to control the particle diameter of the manufactured alumina particles. It is very difficult to control the thinning.
Further, in the method for producing plate-like alumina particles disclosed in Patent Document 2, a crystal control agent is added to aluminum hydroxide or alumina hydrate in which the particles are arranged in advance, and hydrothermal synthesis is performed at 350 ° C. or higher. Although a method has been proposed, there is a problem in that particles having a uniform particle size must be selectively used and a hydrothermal reaction at a high temperature of 350 ° C. is required.
In addition, in the method for producing plate-like alumina particles disclosed in Patent Document 3, a precipitate containing aluminum hydroxide was once produced, then reacted at 90 ° C. for 40 hours, and further the pH of the precipitate was adjusted. Thereafter, a hydrothermal reaction is performed at 180 ° C. for 5 hours, and further, a heat treatment is performed at 600 ° C. for 1 hour, so that there is a problem that the operation is very difficult.
Furthermore, in the method for producing plate-like boehmite particles disclosed in Patent Document 4, a method of hydrothermal synthesis by adding aluminum hydroxide or alumina hydrate in the presence of an alkali metal compound has been proposed. There is a problem that the shape cannot be controlled and the plate boehmite has a non-uniform shape.
On the other hand, when the untreated powder is blended in the cosmetic as it is, the dispersibility with other additives is poor and the powder is hydrophilic, so the makeup is easily broken by sweat or sebum. There is a problem.

Japanese Patent Publication No. 37-7750 JP-A-6-316413 JP 2004-51390 A JP-A-6-263437

  The present invention has been made in view of the above-described problems, and is a plate-like material that can control the particle diameter and can control the aspect ratio and form by an environmentally friendly, simple and low-cost method. By providing a method for producing boehmite and plate-like alumina powder, and also coating the surface of the plate-like boehmite or plate-like alumina powder with a compound such as polysiloxane, an alkylsilane compound, an alkyl titanate compound, or a fluorine compound. It is an object of the present invention to provide a plate-like powder imparted with hydrophobicity, and further to provide a cosmetic having an excellent feeling of use by blending these plate-like powders.

In order to achieve the above-mentioned object, the present inventors have intensively studied, and as a result, by using a water-soluble aluminum compound, sodium hydrogen carbonate and sodium carbonate, and carrying out a hydrothermal reaction, the particle diameter is uniform and the form can be controlled. The manufacturing method of plate boehmite was discovered.
In addition, the plate-like boehmite obtained by the above production method is heat-treated at 400 ° C. to 1500 ° C., so that α, β, γ-alumina alone crystal structure, or plate-like alumina having two or more kinds of crystal structures. A system powder could be obtained.
Furthermore, the obtained plate-like boehmite or plate-like alumina powder is surface-coated with a compound such as polysiloxane, an alkylsilane compound, an alkyl titanate compound, or a fluorine compound to obtain a plate-like powder having hydrophobicity. In addition, it has been found that by blending these plate-like powders into cosmetics, it is possible to provide cosmetics with excellent usability, and the present invention has been completed.

That is, the method for producing plate boehmite according to the first invention is:
The plate surface is polygonal, the average particle diameter is in the range of 1 to 30 μm, and the aspect ratio (average primary particle diameter / average thickness) is in the range of 2 to 50.
A water-soluble aluminum compound is dissolved in water so as to be 0.05 mol / L to 0.2 mol / L, and hydrogen carbonate so that aluminum ions and sodium ions fall within a range of 1: 2 to 1:10 by molar ratio. Sodium and sodium carbonate are added, and it is a manufacturing method characterized by performing hydrothermal reaction for 1 hour-30 hours on the temperature conditions at 180 to 300 degreeC.

The method for producing the plate-like alumina powder according to the second invention is as follows:
The plate-like boehmite obtained in the first invention is calcined at 400 ° C. to 1500 ° C. to have a crystal structure of α, β, γ-alumina alone, or two or more crystal structures. It is a manufacturing method.

The plate-like powder according to the third invention is
The surface of the plate-like boehmite obtained by the production method of the first invention or the plate-like alumina powder obtained by the production method of the second invention is a polysiloxane represented by the following general formula (1), The alkyl alkoxysilane compound represented by the formula (2), the alkyl titanate compound represented by the following general formula (3), the following general formula (4), the following general formula (5), and the fluorine compound represented by the following general formula (6) It is characterized by being coated with one or more compounds selected from
(In the formula, m is an integer of 1 or more and n is an integer of 0 or more. R _{1 to} R ₃ are hydrogen, an alkyl group, an alkoxyl group, or a phenyl group, and may be the same. )
R ₁ Si (OR ₂ ) ₃ (2)
(In the formula, R ₁ and R ₂ are saturated hydrocarbon groups having 1 or more carbon atoms.)
(R ₁ COO) _a Ti (OR ₂ ) _b (3)
(In the formula, R ₁ and R ₂ are each a saturated hydrocarbon group having 1 or more carbon atoms. Further, a and b are each an integer of 1 to 3, and have a relationship of a + b = 4. (The alkyl group shown may be linear or branched and may be single chain length or complex chain length.)
CF ₃ (CF ₂ ) _n CH ₂ CH ₂ Si (OR ₁ ) ₃ (4)
(In the formula, R ₁ is a saturated hydrocarbon group having 1 or more carbon atoms, and n is an integer of 1 or more.)
(In the formula, n is an integer of 4 or more, m is 1 or 2, and M is a monovalent metal ion, ammonium salt or diethanolamine salt.)
(In the formula, n is an integer of 4 or more, and M is a monovalent metal ion, ammonium salt or diethanolamine salt.)

  The cosmetic according to the fourth invention is a plate-like boehmite obtained by the production method of the first invention, a plate-like alumina powder obtained by the production method of the second invention, or the plate-like shape of the third invention. It is characterized by blending powder.

In the first invention, sodium hydrogen carbonate is directly added to an aluminum compound solution adjusted from 0.05 mol / L to 0.2 mol / L so that the molar ratio of aluminum ions to sodium ions is 1: 2 to 1:10. And sodium carbonate was added, and the mixture was stirred until foaming subsided, and then reacted at a temperature of 180 ° C. to 300 ° C. for 1 hour to 30 hours, whereby the morphology was controlled at an average particle size of about 10 μm. A plate-like boehmite having a hexagonal or square polygonal aspect ratio of 2 to 50 can be obtained. Furthermore, in the second invention, the plate-like boehmite obtained in the first invention is baked at 400 ° C. to 1500 ° C., so that α, β, γ-alumina single crystal structure or two or more kinds of crystals are obtained. A plate-like alumina powder having a structure can be obtained.
The obtained plate boehmite or plate-like alumina powder is surface coated with a hydrophobic compound such as polysiloxane, alkylsilane compound, alkyl titanate compound, fluorine compound, and this coated powder is blended into cosmetics. Thus, it is possible to obtain a cosmetic material having good press formability and good usability.

Scanning electron micrograph of plate boehmite obtained in Production Example 1 Scanning electron micrograph of plate boehmite obtained in Production Example 2

  Next, specific embodiments of the method for producing plate boehmite and plate alumina powder according to the present invention, and plate powder and cosmetics containing the same will be described in detail.

The plate-like boehmite and plate-like alumina powder of the present invention have an average primary particle size of about 10 μm and an average thickness of about 1 μm. Further, the shape of the plate surface can be controlled to a hexagonal shape and a square shape depending on reaction conditions.
The average primary particle diameter of the plate-like boehmite and plate-like alumina powder of the present invention is observed with a scanning electron microscope (SEM), and the diameter of any 20 plate-like plate surfaces is measured. It can be measured by calculating an average value. The thickness can be similarly measured.

The aspect ratio of the plate boehmite and the plate alumina powder is preferably 2 to 50. More preferably, it is 5-40.
If the aspect ratio is less than the lower limit, the particles are not plate-like, and the characteristics of plate-like particles cannot be obtained. On the other hand, when the upper limit is exceeded, the obtained plate-like particles become large, the shape is destroyed by a process such as pulverization, and a uniform shape cannot be maintained.

  In the method for producing plate boehmite of the present invention, a water-soluble aluminum compound is dissolved in water so as to be from 0.05 mol / L to 0.2 mol / L, and there is a molar ratio of sodium ions to aluminum ions. So that sodium bicarbonate and sodium carbonate are directly added. Thereafter, stirring is performed until the foaming by the carbon dioxide gas is settled, and after the foaming is settled, the reaction is performed under conditions of 180 ° C. to 300 ° C. for 1 hour to 30 hours, followed by washing with water, filtration, drying, and pulverization. Can produce hexagonal and square plate boehmite.

The water-soluble aluminum compound is a compound selected from the group consisting of inorganic acid salts, lower fatty acid salts, alkoxides, and modified alkoxides in which some of the alkoxy groups are substituted with other functional groups. Examples of the inorganic acid salt include aluminum chloride, aluminum sulfate, and aluminum nitrate. Typical examples of the lower fatty acid salt include acetate. Furthermore, examples of the alkoxide include Al (OCH ₃ ) ₃ , Al (OC ₂ H ₅ ) ₃ , Al (OC ₃ H ₇ -n) ₃ , Al (OC ₃ H ₇ -i) ₃ , Al (OC ₄ H ₉ ) ₃ , Al (OC ₄ H ₉ -i) ₃ , Al (OC ₄ H ₉ -sec) ₃ , Al (OC ₄ H ₉ -tert) _3, etc., but are not limited thereto. Absent. According to the method for producing plate-like boehmite and plate-like alumina powder of the present invention, plate-like boehmite and plate-like alumina-based powder can be most efficiently produced when aluminum nitrate is used.

The molar ratio of sodium ions to aluminum ions is preferably mixed so as to be in the range of 1: 2 to 1:10, but the best condition is 1: 7.
In the above reaction, the reaction temperature is preferably 180 ° C to 300 ° C, but the best condition is in the range of 200 ° C to 250 ° C. When the reaction is performed at 200 ° C., a plate-like powder whose plate surface is controlled to a uniform hexagon is obtained, and when the reaction is performed at 220 ° C., the plate-like powder whose plate surface is controlled to be a uniform square Become. When the temperature condition in the reaction is lower than 180 ° C., a plate-like powder having a uniform shape cannot be obtained, and a shape in which plate-like particles having a fibrous shape or a distorted shape are mixed is obtained. On the other hand, when the temperature is higher than 300 ° C., a load is imposed on the environment and the operation becomes difficult.
In addition, when the reaction time is less than 1 hour, the shape becomes a mixed state of a fiber and a plate. When structural analysis of the particles is performed by X-ray diffraction, an amorphous material containing sodium or the like is obtained. Or it becomes a sodium aluminate state.

  As firing conditions for firing the plate-like boehmite obtained by the above method to obtain a plate-like alumina-based powder, it is preferable to carry out in a temperature range of 400 ° C to 1500 ° C. More preferably, it is the range of 1000 to 1400 degreeC. When the firing temperature is lower than 400 ° C., the conversion to alumina is insufficient, resulting in a plate-like powder having uneven unevenness. Further, when the temperature is higher than 1500 ° C., the treatment is performed at a high temperature and the load on the environment is increased.

  Next, the hydrophobic plate boehmite and plate alumina powder according to the present invention will be described.

  In the present invention, when plate-like boehmite and plate-like alumina-based powder are used as a foundation or sunscreen agent, water resistance is required after application to the skin, so it is necessary to impart hydrophobicity to these powders There is. In order to impart hydrophobicity to the powder, the surface of the powder is coated with a compound such as polysiloxane, an alkylsilane compound, an alkyl titanate compound, or a fluorine compound. In addition to the above compounds, various conventionally known surface treatments can be applied. A plurality of these processes can be combined.

  Specific examples of the surface coating organic compound include methylhydrene polysiloxane, dimethylpolysiloxane, and acrylic silicon copolymer as silicon compounds, and n-octyltriethoxysilane as alkyl titanate as alkylsilane. Isopropyl triisostearoyl titanate, and fluorine-based compounds such as perfluoroalkyl phosphate ester and perfluoroalkylethoxysilane.

  As a treatment method for coating the surface of the hydrophobic compound, the pigment to be coated is stirred in an appropriate mixer, and the compound to be coated is added under a droplet or by spray spraying, and then stirred vigorously at high speed for a certain time. . 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 pigment to the solution while stirring, the organic solvent is completely removed by evaporation, and then the reaction surface coating treatment is performed by heating and aging at 80 to 200 ° C. Can be mentioned.

  As the mixing and dispersing method, an appropriate method can be selected according to the concentration and viscosity of the solution. Preferable 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 biaxial kneader, or a water solution by spraying an aqueous solution and a pigment 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 pigment surface coating treatment is 0.5 to 30% by mass with respect to the pigment 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 plate-like boehmite and plate-like alumina powder of the present invention are blended is not particularly limited, but foundation, sunscreen, serum, lotion, lipstick, beauty cream, facial cleanser, perfume, mouth Examples include 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, and hair restorers. .

  In addition, in cosmetics containing the plate boehmite and plate-like alumina powder of the present invention, in addition to the powder, oils, powders (pigments, dyes, resins), fluorine used in ordinary cosmetics Ingredients such as compounds, resins, surfactants, stickers, preservatives, fragrances, humectants, physiologically active ingredients, salts, solvents, chelating agents, neutralizing agents, and pH adjusters can be blended simultaneously. Here, as the powder, for example, 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 powder, silk powder, urethane powder, Teflon powder (Teflon; registered trademark), silicon powder, cellulose powder, polymers such as silicon elastomer, 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 mica titanium, barium sulfate, calcium carbonate, magnesium carbonate, aluminum silicate, Metal salts such as magnesium silicate, 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 producing plate boehmite and plate alumina powder according to the present invention, and the plate powder and cosmetics containing the plate powder will be described. In addition, this invention is not limited to the Example described below. Hereinafter, an example of preparing plate boehmite and plate-like alumina powder will be referred to as “manufacturing example”, and an example of preparing cosmetics using this powder will be simply referred to as “example”. .

(Production Example 1)
Water was added to 3.751 g of aluminum nitrate nonahydrate and dissolved so that the total amount became 100 ml. After adding 5.881 g of sodium hydrogen carbonate to the solution, the mixture was stirred until foaming subsided. After confirming that foaming subsided, the reaction was allowed to stand at a temperature of 200 ° C. for 24 hours, followed by washing with water. By filtering and drying, plate-like boehmite having a hexagonal plate surface was obtained.
The photograph which observed the plate-like boehmite obtained in manufacture example 1 with the scanning electron microscope (SEM) is shown by Fig.1 (a) (b). As shown in FIG. 1, the obtained plate boehmite was a plate-like powder having a hexagonal plate surface. As a result of observing arbitrary 20 plate boehmite and measuring the average primary particle diameter, it was 11.2 μm and the thickness was 0.95 μm. Therefore, it was found that the aspect ratio was 11.79.

(Production Example 2)
Except having carried out the reaction temperature in manufacture example 1 at 220 degreeC, it carried out similarly to manufacture example 1, and obtained plate-like boehmite with a square plate surface.
A photograph obtained by observing the plate-like boehmite obtained in Production Example 2 with a scanning electron microscope is shown in FIG. As shown in FIG. 2, the obtained plate-like boehmite was a plate-like powder having a square plate surface. As a result of observing arbitrary 20 plate boehmite and measuring the average primary particle diameter, it was 12.4 μm and the thickness was 0.81 μm. Therefore, it was found that the aspect ratio was 15.31.

(Production Example 3)
The plate-like boehmite obtained in Production Example 1 was heat-treated at 1400 ° C. to obtain a plate-like alumina powder having a hexagonal plate surface.

(Production Example 4)
Except having processed using the plate-like boehmite obtained in the manufacture example 2, it processed similarly to the manufacture example 3, and it heat-processed on the conditions at 1400 degreeC, and the plate | board surface is a square plate shape. An alumina powder was obtained.

(Production Example 5)
The plate boehmite 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 plate boehmite 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 with boehmite. Thereafter, the interior of the Henschel mixer was heated and depressurized to remove isopropyl alcohol. The treated powder was taken out of the Henschel mixer, pulverized and heat-treated, and a plate-like boehmite having a hexagonal plate surface treated with 2% by mass of the silicon compound was obtained.

(Production Example 6)
The silicon compound was coated with 2% by mass in the same manner as in Production Example 5 except that the powder treated in Production Example 5 was treated with the plate-like boehmite obtained in Production Example 2. A plate-like boehmite having a square plate surface was obtained.

Example 1
[Manufacture of powder foundation]
A powder foundation was obtained according to the formulation in Table 1 and the following production method. In addition, the unit of the compounding quantity 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)
A product was obtained in the same manner as in Example 1 except that the silicon-treated plate boehmite produced in Production Example 6 was used instead of the silicon-treated plate boehmite produced in Production Example 5.

(Example 3)
[Manufacture of W / O type liquid foundation]
W / O type liquid foundation was manufactured according to the prescription of Table 2 and the following manufacturing method. In addition, the unit of the compounding quantity in a table | surface 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 gradually 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.

Example 4
A product was obtained in the same manner as in Example 2 except that the silicon-treated plate boehmite produced in Production Example 6 was used instead of the silicon-treated plate boehmite produced in Production Example 5.

(Comparative Example 1)
A product was obtained in the same manner as in Example 1 except that silicon-treated sericite was used instead of the silicon-treated plate boehmite produced in Production Example 5.

(Comparative Example 2)
A product was obtained in the same manner as in Example 2 except that silicon-treated sericite was used instead of the silicon-treated plate boehmite produced in Production Example 5.

About each cosmetics produced in Examples 1-4 and Comparative Examples 1 and 2, 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 badly evaluated, 5 points were evaluated as excellent, and the result was expressed as the average score of all panelists. . Therefore, the higher the score, the better the evaluation. The evaluation results are shown in Table 3.
From the results shown in Table 3, both Examples 1 to 4 were superior to Comparative Examples 1 and 2 in terms of feeling of use, makeup lasting, and skin transparency.

  According to the present invention, it is possible to provide a method for producing plate-like boehmite and plate-like alumina powder having an average particle diameter of 1 to 30 μm and an aspect ratio in the range of 2 to 50. By adding a powder coated with a hydrophobic compound to the surface powder, it is possible to provide a cosmetic with excellent use feeling when applied to the skin, a sense of transparency, and a long-lasting makeup. It is suitable for use in makeup cosmetics such as eye shadows, cheeks, and lipsticks, or sunscreen cosmetics, and has great industrial applicability.

Claims (4)

The plate surface is polygonal, the average particle diameter is in the range of 1 to 30 μm, and the aspect ratio (average primary particle diameter / average thickness) is in the range of 2 to 50.
A water-soluble aluminum compound is dissolved in water so as to be 0.05 mol / L to 0.2 mol / L, and hydrogen carbonate so that aluminum ions and sodium ions fall within a range of 1: 2 to 1:10 by molar ratio. A method for producing plate boehmite, comprising adding sodium and sodium carbonate, and performing a hydrothermal reaction for 1 hour to 30 hours under a temperature condition of 180 ° C to 300 ° C.   The plate-like boehmite obtained by the method for producing plate-like boehmite according to claim 1 is calcined at 400 ° C to 1500 ° C, whereby α, β, γ-alumina single crystal structure, or two or more kinds of crystal structures A method for producing a plate-like alumina-based powder characterized by comprising: The surface of the plate-like boehmite obtained by the method for producing a plate-like boehmite according to claim 1 or the plate-like alumina-based powder obtained by the method for producing a plate-like alumina powder according to claim 2 is: The polysiloxane represented by the general formula (1), the alkyl alkoxysilane compound represented by the following general formula (2), the alkyl titanate compound represented by the following general formula (3), the following general formula (4) and the following general formula (5 And a plate-like powder which is coated with one or more compounds selected from fluorine compounds represented by the following general formula (6).
(In the formula, m is an integer of 1 or more and n is an integer of 0 or more. R _{1 to} R ₃ are hydrogen, an alkyl group, an alkoxyl group, or a phenyl group, and may be the same. )
R ₁ Si (OR ₂ ) ₃ (2)
(In the formula, R ₁ and R ₂ are saturated hydrocarbon groups having 1 or more carbon atoms.)
(R ₁ COO) _a Ti (OR ₂ ) _b (3)
(In the formula, R ₁ and R ₂ are each a saturated hydrocarbon group having 1 or more carbon atoms. Further, a and b are each an integer of 1 to 3, and have a relationship of a + b = 4. (The alkyl group shown may be linear or branched and may be single chain length or complex chain length.)
CF ₃ (CF ₂ ) _n CH ₂ CH ₂ Si (OR ₁ ) ₃ (4)
(In the formula, R ₁ is a saturated hydrocarbon group having 1 or more carbon atoms, and n is an integer of 1 or more.)
(In the formula, n is an integer of 4 or more, m is 1 or 2, and M is a monovalent metal ion, ammonium salt or diethanolamine salt.)
(In the formula, n is an integer of 4 or more, and M is a monovalent metal ion, ammonium salt or diethanolamine salt.)   A plate-like boehmite obtained by the method for producing a plate-like boehmite according to claim 1 or a plate-like alumina-based powder obtained by the method for producing a plate-like alumina powder according to claim 2 or A cosmetic comprising the described plate-like powder.