JP2010285609A - Shape-anisotropic tabular particle, method for producing the same, and cosmetic obtained by formulating shape-anisotropic tabular particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new shape-anisotropic tabular particle having a smooth surface in one surface, and an uneven surface in the other surface formed by spherical particles, further having anisotropy in light reflectivity, and exhibiting peculiar reflection effect. <P>SOLUTION: The shape-anisotropic tabular particle is composed of a tabular acrylic polymer particle and the spherical particles, of which one surface is the smooth surface (a) formed of an acrylic polymer 2, and of which the other surface is the uneven surface (b) formed of the spherical particles 3 protruded from the acrylic polymer. The shape-anisotropic tabular particle is produced by dissolving the acrylic polymer in a solvent, adding the spherical particles thereto to prepare a dispersion solution, spreading the dispersion solution on the surface of a liquid immiscible with the solvent to form a thin film, taking out the thin film, thereafter removing the solvent from the thin film, and pulverizing the thin film. The invention is useful for the formulation of a cosmetic. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a shape-anisotropic plate-like particle, that is, a plate-like particle in which one surface and the other surface have different shapes with respect to one plate-like particle. Moreover, this invention relates to the manufacturing method of this shape anisotropic plate-like particle, and the cosmetics containing this shape anisotropic plate-like particle.

Conventionally, various composite particles with various functions such as coating the surface of particles with other fine particles have been proposed. In recent years, anisotropic particles have been proposed by giving anisotropy to one particle. Has been. For example, surface anisotropic polymer particles having a particle size of 0.01 to 10000 μm having different performances (for example, hydrophilicity and hydrophobicity, positive charge and negative charge) on one side surface and the other side surface of the polymer particles are proposed. The surface anisotropic polymer particles are produced by treating one surface of the polymer particles with a drug and then treating the other side with another drug or not with the drug ( Patent Document 1).

In addition, the surface of the base powder such as silicone resin powder, acrylic resin powder, polyethylene resin powder, nylon resin powder is densely coated locally with hydrophilic substances such as silicon oxide, aluminum oxide, titanium oxide, and zinc oxide. An anisotropic particle is proposed, and a hydrophilic substance is prepared from the anisotropic particle in the water-in-oil emulsion of the water-in-oil emulsion containing the above base powder, and the base powder is obtained from the hydrophilic substance. It has been proposed that the surface of the film is locally densely manufactured (Patent Document 2). Furthermore, a method for producing shape-anisotropic particles is proposed in which multi-phase polymer particles comprising two or more types of polymers having different solubility parameters are produced, and a part of the polymer forming the multi-phase polymer particles is selectively removed. (Patent Document 3).

Conventionally, various methods for producing resin fine particles have been proposed. One of them is a homopolymer of styrene, methacrylic acid ester or acrylic acid ester or a copolymer of these with other monomers. A polymer solution in which a linear polymer is dissolved in an organic solvent is developed into a film on the liquid surface of a liquid layer that is liquid at room temperature, and the solvent is removed to form a thin film on the liquid layer. A method for producing a plate-like polymer fine powder by pulverization has been proposed (Patent Document 4).

Japanese Patent No. 3567269 JP 2007-302823 A JP 2008-74915 A Japanese Patent No. 3825650

Conventionally, spherical particles are known as anisotropic particles. The present invention provides an anisotropic plate-like particle, that is, a new shape-anisotropic plate-like powder in which one surface and the other surface have different shapes for one plate-like particle. Objective. Furthermore, it aims at providing the manufacturing method of this shape anisotropic plate-like particle | grain, the skin external preparation containing this shape anisotropic plate-like particle, and cosmetics.

The present invention is a plate-like particle comprising plate-like acrylic polymer particles and spherical particles, wherein one surface of the plate-like particle is a smooth surface formed of an acrylic polymer, and the other surface is acrylic. It is a shape anisotropic plate-like particle characterized by being an uneven surface formed by spherical particles protruding from a polymer. The acrylic polymer is preferably a homopolymer or copolymer of a monomer selected from an acrylic acid alkyl ester and a methacrylic acid alkyl ester, or a copolymer with another monomer. The spherical particles are preferably one or more spherical particles selected from silica particles, silicone resin particles, acrylic resin particles, polyethylene resin particles, polystyrene resin particles, and nylon resin particles. Further, the shape anisotropic plate-like particles preferably have an average particle size of 10.0 to 70.0 μm, and the aspect ratio (average particle size / average thickness) of 1 to 140 is preferable. The ratio (A) / (B) of the thickness (A) of the shape-anisotropic plate-like particles and the average particle diameter (B) of the spherical powder is preferably 0.025 to 10. Moreover, this invention is a skin external preparation formed by mix | blending the above-mentioned anisotropic plate-shaped particle | grain, and is cosmetics formed by mix | blending the above-mentioned anisotropic plate-shaped particle.

Furthermore, this invention is a manufacturing method of the above-mentioned shape anisotropic plate-like particle. That is, in the present invention, an acrylic polymer is dissolved in a solvent, spherical particles are added thereto to prepare a dispersion solution, and the dispersion solution is spread on a liquid surface immiscible with the solvent to form a thin film. Then, the method for producing anisotropic plate-like particles is characterized in that the thin film is taken out, and then the solvent is removed from the thin film and pulverized. The solvent is preferably ethyl acetate and / or methyl ethyl ketone. The liquid is preferably water.

The shape-anisotropic plate-like particle of the present invention is a smooth surface formed on one surface with an acrylic polymer, and the other surface is an uneven surface formed with spherical particles protruding from the acrylic polymer. For this reason, the shapes of both surfaces are different, and there is anisotropy in light reflectivity and the like. For example, makeup with a specific reflection effect can be expected by blending into cosmetics. Therefore, it can be suitably used for external preparations for skin and cosmetics.

It is a perspective view which shows the general external shape of an example of the shape anisotropic plate-like particle | grains of this invention. It is a schematic diagram of the cross section of the shape anisotropic plate-like particle | grains of this invention. It is an electron micrograph which shows the shape of the both surfaces of the dried thin film in the manufacture process of the shape anisotropic plate-shaped particle | grains of this invention.

The shape-anisotropic plate-like particle referred to in the present invention refers to a plate-like particle in which one surface and the other surface have different shapes for one plate-like particle. FIG. 1 is a perspective view showing the general outline of an example of the anisotropic plate-like particle of the present invention. 1 is a shape anisotropic plate-like particle. FIG. 2 is a schematic diagram of a cross section of an example of the shape anisotropic plate-like particle of the present invention. 2 is an acrylic polymer. 3 is a spherical particle. One surface a of the shape anisotropic plate-like particle is a smooth surface formed of the acrylic polymer 2. The other surface b is an uneven surface formed by spherical particles 3 protruding from the acrylic polymer 2. The smoothness of the smooth surface a has an unevenness difference of 50 nm or less (surface shape roughness measurement: non-contact type three-dimensional optical interference type surface roughness measuring device WYKO NT-1100, measurement mode PSI, measurement range 50 times ( (Measurement under the condition of 0.09 × 0.12 mm) is preferable. Moreover, when the uneven surface b is expressed by the unevenness difference between the acrylic polymer surface and the spherical particles protruding therefrom, an unevenness difference of 0.8 μm or more is preferable. This unevenness difference is different depending on the particle size of the spherical particles. According to experiments, when spherical particles having a minimum particle diameter range of 1.0 μm are used, the unevenness difference is such that part of the spherical particles is on the surface of the acrylic polymer. The thickness is smaller than 1.0 μm.

The acrylic polymer used in the present invention is a homopolymer of a monomer selected from an alkyl acrylate ester and an alkyl methacrylate ester, a copolymer thereof, or a copolymer with other monomers. Preferably used. These polymers have an advantage that it is easy to produce a thin film, and thus easy to produce plate-like particles. Examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, and the like. Examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, and 2-ethylhexyl methacrylate. Is mentioned. These homopolymers or copolymers are used.

Moreover, the copolymer of said acrylic acid alkylester or methacrylic acid alkylester and another monomer is also used. Other monomers include acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, styrene, ethylene, propylene, and the like. By selecting a monomer to be copolymerized, the acrylic polymer can be made hydrophilic or hydrophobic. For example, to make it hydrophilic or hygroscopic, acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, polyethylene glycol macromonomer, and the like are copolymerized. In order to make it hydrophobic, a silicone compound having a vinyl group such as a dimethylpolysiloxane macromonomer represented by the following general formula (1) is copolymerized.

（式中、Ｒ₁は水素またはメチル基を示し、Ｘは、炭素数２〜５の２価の炭化水素基を示し、Ｒ₂は炭素数１〜５の炭化水素基を示し、ｎは１〜２００の数を示す）

(Wherein R ₁ represents hydrogen or a methyl group, X represents a divalent hydrocarbon group having ₂ to 5 carbon atoms, R ₂ represents a hydrocarbon group having 1 to 5 carbon atoms, and n represents 1 Indicates a number of ~ 200)

Specific examples of the acrylic polymer include polymethyl methacrylate, a copolymer of methyl methacrylate and styrene, a copolymer of methyl methacrylate and methyl acrylate, and a copolymer of methyl methacrylate and ethyl acrylate. And a terpolymer of methyl methacrylate, methyl acrylate and methacrylic acid. When a methacrylic resin containing 50% by mass or more of a methyl methacrylate unit is used as the acrylic polymer, plate-like particles excellent in transparency, spreadability, adhesion and the like are easily obtained. A methacrylic resin containing 75% by mass to 99% by mass of methyl methacrylate units and 1% by mass to 25% by mass of alkyl acrylate units is particularly excellent in transparency and is preferable because it is easily dissolved in an organic solvent. When the average degree of polymerization of the methacrylic resin is about 600 or more and 1300 or less, the solution viscosity of the polymer solution is low, so that a thin film with a small thickness, and thus a thin plate-like particle is easily obtained.

Examples of the spherical particles used in the present invention include silica particles, silicone resin particles, acrylic resin particles, polyethylene resin particles, polystyrene resin particles, and nylon resin particles. One or more of these can be used as appropriate. Further, in order to make the uneven surface where the spherical particles are exposed hydrophilic, hydrophilic spherical particles such as spherical silica particles are used. In order to make the uneven surface hydrophobic, hydrophobic silicone resin particles or the like are used. It is also possible to apply the spherical particles after previously hydrophilizing or hydrophobizing them. The spherical particles preferably have an average particle size of 1.0 to 10.0 μm. In the present invention, a laser type dry particle size distribution measuring device (PRO7000S manufactured by Seishin Enterprise Co., Ltd.) was used to measure the average particle size.

The size of the shape-anisotropic plate-like particles of the present invention is preferably an average particle diameter of 10 to 70 μm, but specifically, it is determined according to the purpose of use. When mix | blending with cosmetics, Preferably it is 10.0-50.0 micrometers, More preferably, it is 10.0-30.0 micrometers. Moreover, the aspect ratio (average particle diameter / average thickness) is 1-140.

Next, the manufacturing method of the shape anisotropic plate-like particle of the present invention will be described. The shape anisotropic plate-like particles in which one surface of the present invention is a smooth surface of an acrylic polymer and the other surface is an uneven surface of a spherical particle are obtained by dissolving an acrylic polymer in a solvent and forming a spherical A dispersion solution is prepared by adding particles, the dispersion solution is spread on a liquid surface immiscible with the solvent to form a thin film, and then the thin film is taken out, and then the solvent is removed from the thin film and pulverized. Can be manufactured. The “liquid not miscible with the solvent” is preferably a liquid having a solvent solubility of 50 mass% or less (the solubility of the solvent in the liquid is 50 mass% or less).

In these production methods, examples of the organic solvent used for dissolving the acrylic polymer include solvents of ketones or esters having 2 to 8 carbon atoms, such as methyl ethyl ketone, diethyl ketone, methyl acetate, ethyl acetate, and butyl acetate. . These can be used as a mixed solvent in which two or more types are mixed to adjust the compatibility with the liquid. The acrylic polymer solution can be produced, for example, by dissolving the acrylic polymer in an organic solvent so that the polymer concentration is 5 to 30% by mass. The acrylic polymer solution preferably has a solution viscosity (20 ° C.) of about 5 to 50 pascal seconds (Pa · S) (about 50 to 500 centipoise). Spherical particles are added to and dispersed in the prepared acrylic polymer solution and used for the production of a thin film. The addition amount of the spherical particles is 5 to 30% by mass of the acrylic polymer solution.

The acrylic polymer solution in which the spherical particles are dispersed is developed in the form of a film on the liquid surface of a liquid at room temperature (a liquid immiscible with a solvent, such as water), and is removed by volatilization or transfer to the liquid. A solvent is used to form an acrylic polymer thin film on the liquid layer. The acrylic polymer solution can be easily developed in the form of a film on the liquid surface by dropping the acrylic polymer solution on the liquid surface and allowing it to float and develop. The thickness of the thin film and thus the thickness of the plate-like particles are adjusted by the amount of polymer solution dripped onto the liquid surface of the liquid layer, the viscosity, and the like. When the polymer solution is developed on the liquid layer so that the amount of the acrylic polymer is 0.1 g to 50 g per 1 m ² of the liquid surface of the liquid layer, a thin film having a thickness of about 0.1 μm to 50 μm As a result, plate-like particles are obtained.

The liquid used for the liquid layer is a liquid that is not miscible with the solvent, and water, an alcohol having 1 to 4 carbon atoms (methanol, ethanol, or the like), or an aqueous solution in which an alcohol and water are mixed. From the viewpoint of ease of handling, cost, ease of production of the thin film, and the like, water containing 70% by mass or more, preferably 90% by mass or more is preferable. In addition, an inorganic salt aqueous solution in which a water-soluble inorganic salt is dissolved in water can easily adjust the specific gravity to 1 or more. Therefore, when used as a liquid layer, it is easy to produce a thin film. Examples of inorganic salts are sodium chloride, sodium sulfate and the like. Inorganic salts can be used at a ratio of about 5 to 50 parts by mass with respect to 100 parts by mass of water. The temperature of the liquid layer is preferably in the range of 0 ° C to 30 ° C. In particular, the range of 10 ° C. to 25 ° C. is preferable because the thin film has good formability and good workability.

Next, the thin film formed on the liquid layer is collected. The collected thin film is subjected to vacuum filtration or the like to remove liquid such as water, dried, and pulverized by a pulverizer to obtain a fine powder (aggregate of plate-like particles). FIG. 3 is an electron micrograph of the dried thin film. Here, (A) is a gas (air) -liquid (ethyl acetate) side interface, that is, an electron micrograph of the side in contact with gas (air), and (B) is a liquid (ethyl acetate) -liquid (water) side interface. That is, it is an electron micrograph of the surface in contact with the liquid (water). As the electron microscope, a scanning electron microscope (real surface view VE-7800) was used, and the surface was observed under the conditions of 1.0 kV and 1000 times. The (A) surface is formed of an acrylic polymer and is smooth, and the (B) surface is formed with irregularities by spherical particles protruding from the acrylic polymer. As the pulverizer, a ball mill, an impact pulverizer, a jet pulverizer, or the like is used. As the pulverization method, freeze pulverization is preferred in which the thin film is crushed while cooling the thin film with a coolant such as a liquefied gas having a boiling point of about −30 ° C. or less, preferably about −70 ° C. or less. The surface shape of the plate-like particles obtained by pulverizing the thin film is the same as the surface shape of the thin film.

Moreover, the blending amount of the shape anisotropic plate-like particles used in the external preparation for skin and cosmetics of the present invention is preferably 0.5 to 60% by mass, more preferably 3 to 40% by mass with respect to the entire cosmetics. %. If within this blending amount range, one surface of the shape-anisotropic plate-like particle of the present invention is a smooth surface formed with an acrylic polymer, and the other surface is a spherical particle protruding from the acrylic polymer. By using the light-reflecting anisotropy of the shape-anisotropic plate-like particles of the present invention, which is an uneven surface formed by the above, makeup having a specific reflection effect can be expected.

A 500 mL three-necked flask was equipped with a nitrogen introduction tube, a dropping funnel, and a cooling tube, and 150 mL of toluene was added to replace the nitrogen. To this was added 39.6 g of methyl methacrylate, 0.35 g of methyl acrylate, 1.30 g of N, N-azobisisobutyronitrile, and the mixture was stirred under nitrogen bubbling at 70 ° C. for 3 hours. After cooling, the produced white solid was collected, washed thoroughly with methanol and dried to obtain 30.0 g of a copolymer. The weight average molecular weight (Mw) in terms of polystyrene by GPC of the obtained polymer was 100,000. The obtained polymer was an acrylic polymer having a copolymer composition of 99 mol% methyl methacrylate and 1 mol% methyl acrylate.

The acrylic polymer obtained above is uniformly dissolved in ethyl acetate so as to be a 10% by mass solution, and then hydrophilic silica powder having an average particle size of 0.3 μm so as to be 20% by mass with respect to the polymer. (Fuso Chemical Co., Ltd. SP-03F) was added to prepare a dispersion. This dispersion is dropped on a water surface at a rate of 20 g per 1 m ² of liquid surface and spread, and ethyl acetate volatilizes or moves to water on the water surface to solidify the acrylic polymer and form a thin film. I let you. This thin film was allowed to stand for 5 minutes, then separated from water and collected, dehydrated and dried, and the solvent was removed to obtain a thin film. This thin film had a smooth surface in contact with the upper air, and a surface in contact with water on the lower side had irregularities formed of silica particles (FIG. 3). The solvent-removed thin film was put into liquid nitrogen and the thin film was pulverized to obtain plate-like particles of the present invention. The average particle diameter of the obtained powder was 40 μm, and the average thickness was 2 μm.

The acrylic polymer having a copolymer composition of 99 mol% of methyl methacrylate and 1 mol% of methyl acrylate obtained in Example 1 was uniformly dissolved in ethyl acetate so as to be a 10 mass% solution, and then the polymer was added to the polymer. The dispersion liquid was prepared by adding hydrophilic silica powder (SP-1B manufactured by Fuso Chemical Industry Co., Ltd.) having an average particle diameter of 1.0 μm so as to be 20 mass%. This dispersion is dropped on a water surface at a rate of 20 g per 1 m ² of liquid surface and spread, and ethyl acetate volatilizes or moves to water on the water surface to solidify the acrylic polymer and form a thin film. I let you. This thin film was allowed to stand for 5 minutes, then separated from water and collected, dehydrated and dried, and the solvent was removed to obtain a thin film. This thin film had a smooth surface in contact with the upper air, and a surface in contact with water on the lower side had irregularities formed of silica particles (FIG. 3). The solvent-removed thin film was put into liquid nitrogen and the thin film was pulverized to obtain plate-like particles of the present invention. The average particle diameter of the obtained powder was 30 μm, and the average thickness was 2 μm.

The acrylic polymer having a copolymer composition of 99 mol% of methyl methacrylate and 1 mol% of methyl acrylate obtained in Example 1 was uniformly dissolved in ethyl acetate so as to be a 10 mass% solution, and then the polymer was added to the polymer. A dispersion liquid was prepared by adding hydrophilic silica powder (Gotball E2-824C, manufactured by Suzuki Yushi Kogyo Co., Ltd.) having a particle size of 0.5-3.0 μm (particle size distribution of 70% or more) so that the total amount was 20% by mass. . Furthermore, this dispersion is dropped on a water surface at a rate of 20 g per 1 m ² of the liquid surface and allowed to develop, and ethyl acetate volatilizes or moves to water on the water surface to solidify the acrylic polymer to form a thin film. Formed. This thin film was allowed to stand for 5 minutes, then separated from water and collected, dehydrated and dried, and the solvent was removed to obtain a thin film. This thin film had a smooth surface in contact with the upper air, and a surface in contact with water on the lower side had irregularities formed of silica particles (FIG. 3). The solvent-removed thin film was put into liquid nitrogen and the thin film was pulverized to obtain plate-like particles of the present invention. The average particle diameter of the obtained powder was 50 μm and the average thickness was 2 μm.

The acrylic polymer having a copolymer composition of 99 mol% of methyl methacrylate and 1 mol% of methyl acrylate obtained in Example 1 was uniformly dissolved in ethyl acetate so as to be a 10 mass% solution, and then the polymer was added to the polymer. The dispersion liquid was prepared by adding hydrophilic silica powder (Gotball D11-796C, manufactured by Suzuki Yushi Kogyo Co., Ltd.) having a particle size of 2.0-5.0 μm (particle size distribution of 70% or more) so as to be 20% by mass. . Furthermore, this dispersion is dropped on a water surface at a rate of 20 g per 1 m ² of the liquid surface and allowed to develop, and ethyl acetate volatilizes or moves to water on the water surface to solidify the acrylic polymer to form a thin film. Formed. This thin film was allowed to stand for 5 minutes, then separated from water and collected, dehydrated and dried, and the solvent was removed to obtain a thin film. This thin film had a smooth surface in contact with the upper air, and a surface in contact with water on the lower side had irregularities formed of silica particles (FIG. 3). The solvent-removed thin film was put into liquid nitrogen and the thin film was pulverized to obtain plate-like particles of the present invention. The average particle diameter of the obtained powder was 35 μm, and the average thickness was 2 μm.

A 500 mL three-necked flask was equipped with a nitrogen introduction tube, a dropping funnel, and a cooling tube, and 150 mL of toluene was added to replace the nitrogen. To this was added 39.2 g of methyl methacrylate, 0.35 g of methyl acrylate, 8.0 g of silicone macromonomer (RES-422 manufactured by Shin-Etsu Chemical Co., Ltd.), 1.30 g of N, N-azobisisobutyronitrile, The mixture was stirred while bubbling nitrogen at 70 ° C. for 3 hours. After cooling, the produced white solid was collected, washed thoroughly with methanol and dried to obtain 32.5 g of a copolymer. The weight average molecular weight (Mw) in terms of polystyrene by GPC of the obtained polymer was 40000. The resulting polymer was an acrylic polymer having a copolymer composition of 98 mol% methyl methacrylate, 1 mol% methyl acrylate, and 1 mol% silicone macromonomer.

The obtained acrylic polymer was uniformly dissolved in ethyl acetate so as to be a 10% by mass solution, and then the particle size was 2.0-5.0 μm (particle size distribution 70) so as to be 20% by mass with respect to the polymer. % Or more) hydrophilic silica powder (Gotball D11-796C, manufactured by Suzuki Yushi Kogyo Co., Ltd.) was added to prepare a dispersion. Furthermore, this dispersion is dropped on a water surface at a rate of 20 g per 1 m ² of the liquid surface and allowed to develop, and ethyl acetate volatilizes or moves to water on the water surface to solidify the acrylic polymer to form a thin film. Formed. This thin film was allowed to stand for 5 minutes, then separated from water and collected, dehydrated and dried, and the solvent was removed to obtain a thin film. This thin film had a smooth surface in contact with the upper air, and a surface in contact with water on the lower side had irregularities formed of silica particles (FIG. 3). The solvent-removed thin film was put into liquid nitrogen and the thin film was pulverized to obtain plate-like particles of the present invention. The average particle diameter of the obtained powder was 35 μm, and the average thickness was 3.0 μm.

[Comparative Example 1]
The acrylic polymer having a copolymer composition of 99 mol% of methyl methacrylate and 1 mol% of methyl acrylate obtained in Example 1 was uniformly dissolved in ethyl acetate so as to be a 10 mass% solution, and this solution was allowed to stand still. It was dropped and developed at a rate of 20 g per 1 m ² of the liquid level on the water surface, and the acrylic polymer was solidified on the water surface by volatilizing or transferring to water, thereby forming a thin film. This thin film was allowed to stand for 5 minutes, then separated from water and collected, dehydrated and dried, and the solvent was removed to obtain a thin film. The thin film had a smooth surface in contact with the upper air and a surface in contact with the lower water (FIG. 3). The solvent-removed thin film was put into liquid nitrogen, and the thin film was pulverized to obtain plate-like particles. The average particle diameter of the obtained powder was 40 μm, and the average thickness was 2.0 μm.

[Comparative Example 2]
The acrylic polymer having a copolymer composition of 98% by mole of methyl methacrylate, 1% by mole of methyl acrylate and 1% by mole of silicone macromonomer obtained in Example 5 was uniformly added to a 10% solution in ethyl acetate. Dissolve and drop this solution onto the water surface in a stationary state at a rate of 20 g per 1 m ² of liquid surface, and ethyl acetate volatilizes or migrates to water on the water surface to solidify the acrylic polymer and form a thin film Formed. This thin film was allowed to stand for 5 minutes, then separated from water and collected, dehydrated and dried, and the solvent was removed to obtain a thin film. The thin film had a smooth surface in contact with the upper air and a surface in contact with the lower water. The solvent-removed thin film was put into liquid nitrogen and the thin film was pulverized to obtain plate-like particles of the present invention. The average particle diameter of the obtained powder was 40 μm and the average thickness was 3.0 μm.

Table 1 shows the results of examining the shape of the surface of one surface and the other surface of the plate-like particles obtained in Examples 1 to 5 and Comparative Examples 1 and 2. The plate-like particles obtained in Examples 1 to 5 had different shape on the surface of one surface and the other surface, and had shape anisotropy.

This example is an example of white powder blended with shape anisotropic plate-like particles.
(Ingredient) (mass%)
1. 1. Mica remaining amount Synthetic phlogopite 10.0
3. Shape anisotropic plate-like particle of Example 2 20.0
4). Cross-linked polystyrene (Note 1) 5.0
5). Nylon powder 5.0
6). Talc 30.0
7). Mica titanium 10.0
8). Perfume appropriate amount (Note 1) Gantz Pearl GS-0605 (manufactured by Gantz Kasei)
(Production method)
A: 1 to 8 are uniformly dispersed with a Henschel mixer (Mitsui Miike).
B: A is pulverized with a pulverizer and filled into a container.
The resulting white powder has excellent sliding effects when applied to the skin, soft feel, and close contact with the skin, and particularly has high cosmetic effects such as no dullness of the cosmetic film over time, and long-lasting transparency. It is a good white powder.

This example is an example of a solid powder eye shadow in which shape anisotropic plate-like particles are blended.
(Ingredient) (mass%)
1. Mica titanium 30.0
2. 2. Talc remaining amount Shape anisotropic plate-like particle of Example 4 3.0
4). Yellow 401 No. 1.0
5). Red No. 202 0.2
6). Nylon powder 2.0
7). Glyceryl tri-2-ethylhexanoate 4.0
8). Liquid paraffin 4.0
9. Vaseline 1.0
10. Methyl paraoxybenzoate 0.3
11. Fragrance 0.1
(Production method)
A: Components 1 to 6 are mixed uniformly.
B: Components 7 to 11 are added to A and mixed uniformly.
C: B is pulverized with a pulverizer.
D: C was filled in a metal pan to obtain a solid powder eye shadow.
The resulting white powder has excellent sliding effects when applied to the skin, soft feel, and close contact with the skin, and particularly has high cosmetic effects such as no dullness of the cosmetic film over time, and long-lasting transparency. It is an excellent solid powder eye shadow.

This example is an example of a solid powder foundation in which shape anisotropic plate-like particles are blended.
(Ingredient) (mass%)
1. Silicone-treated titanium oxide (Note 2) 15.0
2. 2. Talc remaining amount Shape-anisotropic plate-like particles of Example 2.0 2.0
4). Silicone-treated Bengala (Note 2) 0.3
5). Silicone-treated yellow iron oxide (Note 2) 0.5
6). Silicone-treated black iron oxide (Note 2) 0.1
7). Mica 20.0
8). Nylon powder 2.0
9. Glyceryl tri-2-ethylhexanoate 3.0
10. Liquid paraffin 2.0
11. 2-Ethylhexyl paramethoxycinnamate 2.0
12 Methyl paraoxybenzoate 0.2
13. Fragrance 0.15
(Note 2) Treatment with 3% dimethylpolysiloxane and methylhydrogenpolysiloxane (manufacturing method)
A: Components 1 to 8 are mixed uniformly.
B: Components 9 to 13 are added to A and mixed uniformly.
C: B is pulverized with a pulverizer.
D: C was filled into a metal pan to obtain a solid powdery foundation.
The resulting white powder has excellent sliding effects when applied to the skin, soft feel, and close contact with the skin, and particularly has high cosmetic effects such as no dullness of the cosmetic film over time, and long-lasting transparency. It is a very good solid powder foundation.

DESCRIPTION OF SYMBOLS 1 Anisotropic plate-like particle, 2 Acrylic polymer, 3 Spherical particle, a Smooth surface formed with acrylic polymer, b Uneven surface formed with spherical particle

Claims (11)

  Plate-like particles comprising plate-like acrylic polymer particles and spherical particles, wherein one surface of the plate-like particles is a smooth surface formed of an acrylic polymer, and the other surface is an acrylic polymer. A shape-anisotropic plate-like particle characterized by being an uneven surface formed by spherical particles protruding from the surface.   The acrylic polymer is a homopolymer or copolymer of a monomer selected from an alkyl acrylate ester and an alkyl methacrylate ester, or a copolymer with another monomer. Shape anisotropic plate-like particles.   The shape anisotropic plate-like particle according to claim 1 or 2, wherein the spherical particles are one or more selected from silica particles, silicone resin particles, acrylic resin particles, polyethylene resin particles, polystyrene resin particles, and nylon resin particles. .   The shape anisotropic plate-like particle according to any one of claims 1 to 3, wherein the average particle diameter is 10.0 to 70.0 µm.   The shape anisotropic plate-like particle according to claim 1, wherein the aspect ratio (average particle diameter / average thickness) is 1-140.   The ratio (A) / (B) of the thickness (A) of the shape-anisotropic plate-like particles and the average particle diameter (B) of the spherical particles is 0.025-10, 6. Shape anisotropic plate-like particles.   The external preparation for skin formed by mix | blending the shape anisotropic plate-shaped particle in any one of Claims 1-6.   Cosmetics which mix | blend the shape anisotropic plate-shaped particle in any one of Claims 1-6.   An acrylic polymer is dissolved in a solvent, spherical particles are added thereto to prepare a dispersion solution, and the dispersion solution is spread on a liquid surface immiscible with the solvent to form a thin film. 2. The method for producing shape-anisotropic plate-like particles according to claim 1, wherein the solvent is removed from the thin film and then pulverized.   The method for producing shape-anisotropic plate-like particles according to claim 9, wherein the solvent is ethyl acetate and / or methyl ethyl ketone.   The method for producing shape-anisotropic plate-like particles according to claim 9 or 10, wherein the liquid is water.

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