Composite powder and method for producing composite powder

Abstract

The present invention provides a composite powder having excellent smoothness and flexibility. According to the present invention, provided is a composite powder containing mica, a coating layer, and spherical particles, the coating layer covers the mica, the spherical particles are adhered to the mica or the coating layer, and the coating layer and the spherical particles are configured from a water-resistant organic material.

Description

[Technical field]

[0001] The present invention relates to a composite powder and a method for producing the composite powder. [Background Technology]

[0002] Various powders have been developed in cosmetics such as cosmetics and skin care products using inorganic materials such as silica, talc, and mica, and synthetic resin materials such as polyurethane and polyethylene. However, it is difficult to obtain a composite powder that has both smoothness and soft focus property (light diffusion) when applied to the skin.

[0003] In addition, in view of the problem of microplastics, which has been pointed out in recent years as a source of environmental problems such as marine pollution, people are studying cosmetics that reduce the use of synthetic resin particles that can become microplastics or do not contain synthetic resin particles that can become microplastics.

[0004] For example, Patent Document 1 discloses a starch-coated powder, which is characterized in that the surface of the powder is coated with starch. [Prior art documents] [Patent Document]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2011-140444 [Summary of the invention] [Problems to be solved by the invention]

[0006] However, it is difficult to obtain composite powders with excellent smoothness and soft focus properties using existing technologies.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a composite powder having excellent smoothness and soft focus properties. [Technical solutions to solve the problem]

[0008] According to the present invention, there is provided a composite powder comprising mica and spherical particles, wherein the mica is coated with a water-resistant organic material, the spherical particles contain the water-resistant organic material, and the spherical particles are attached to the mica.

[0009] As a result of diligent research, the inventors discovered that in a composite powder containing mica and spherical particles, by coating the mica with a water-resistant organic material and attaching the spherical particles containing the water-resistant organic material to the mica, a composite powder with excellent smoothness and soft focus properties can be made, thereby completing the present invention.

[0010] Various embodiments of the present invention are described below. The embodiments described below can be combined with each other. [1] A composite powder comprising mica, a coating layer, and spherical particles, wherein the coating layer covers the mica, the spherical particles are attached to the mica or the coating layer, and the coating layer and the spherical particles are composed of a water-resistant organic material. [2] The composite powder as described in [1], wherein the average friction coefficient is less than 0.75 and the soft focus coefficient is greater than 0.86. [3] The composite powder according to [1] or [2], wherein the composite powder contains 10 parts by mass or more of the water-resistant organic material based on 100 parts by mass of the mica. [4] The composite powder according to any one of [1] to [3], which is used in cosmetics. [5] A method for producing a composite powder, which is a method for producing a composite powder as described in any one of [1] to [4], the aforementioned production method comprising a dispersion preparation step, a spray drying step, and a water resistance treatment step, wherein in the aforementioned dispersion preparation step, a dispersion containing the aforementioned mica and a precursor organic material is prepared, in the aforementioned spray drying step, a composite powder precursor is obtained by spray drying the aforementioned dispersion, and in the aforementioned heat treatment step, the aforementioned composite powder precursor is heat-treated to convert at least a portion of the aforementioned precursor organic material into the aforementioned water-resistant organic material. [6] The production method according to [5], wherein the solubility of the precursor organic material when immersed in water at 25°C for 3 days is higher than the solubility of the water-resistant organic material when immersed in water at 25°C for 3 days by 5% by mass or more. [Effects of the invention]

[0011] The composite powder of the present invention has excellent smoothness and soft focus. In addition, according to the method for producing the composite powder of the present invention, a composite powder having excellent smoothness and soft focus can be provided. The composite powder of the present invention can be used in cosmetics by utilizing its characteristics. [Drawings]

[0012] Figure 1 This is a SEM photograph of the composite powder 1 of Example 1. [Specific implementation method]

[0013] Hereinafter, the present invention will be described in detail by way of examples of the embodiments of the present invention. The present invention is not limited by these descriptions. The various characteristic matters of the embodiments of the present invention shown below can be combined with each other. In addition, each characteristic matter independently constitutes an invention.

[0014] 1. Constituent elements of composite powder The composite powder of the present invention is a composite powder comprising mica, a coating layer, and spherical particles, wherein the coating layer covers the mica, the spherical particles are attached to the mica or the coating layer, and the coating layer and the spherical particles are composed of a water-resistant organic material.

[0015] 1.1 Mica The composite powder of the present invention contains mica. The mica may be plate-shaped or flaky. The mica may be natural mica or synthetic mica. The average particle size of the mica may be 5 to 100 μm, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 μm, or may be within the range between any two of the values ​​exemplified here. In addition, the average particle size of mica refers to the average value (particle size value of 50% cumulative volume) of the width and length of the powder measured in a dispersed state in water using a laser diffraction / scattering particle size distribution measuring device. The aspect ratio of the mica may be 20 to 200, for example, 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, or may be within the range between any two of the values ​​exemplified here. Additionally, the aspect ratio may be the major diameter / thickness of the mica.

[0016] 1.2 Coating layer The mica of the present invention is at least partially coated with a coating layer, and preferably the entire mica is coated with a coating layer. Whether the mica is coated with a coating layer can be confirmed by SEM observation, EDS (energy dispersive X-ray analysis), extracting a composite powder precursor in the manufacturing step and re-dissolving the precursor organic material coating the mica to confirm its quality, etc. The composite powder of the present invention has better soft focus than conventional powders because the mica is coated with a coating layer composed of a water-resistant organic material.

[0017] 1.3 Spherical particles The composite powder of the present invention contains spherical particles. Spherical particles also include particles that are approximately spherical, and are intended to mean particles with rounded corners. The maximum diameter / minimum diameter of the spherical particles is preferably 0.5 to 1.5, and more preferably 0.8 to 1.2. In addition, spherical particles may also include partially deformed or cut spherical shapes such as hemispherical (lens-shaped, etc.) particles, but preferably at least half of the particles have a maximum diameter / minimum diameter within the above numerical range. In addition, from the viewpoint of soft focus and smoothness, the spherical particles preferably have a smooth surface with few depressions and wrinkles.

[0018] At least one spherical particle is attached to the mica or the coating layer of the present invention, and preferably at least one spherical particle is attached to the two main surfaces of the mica directly or via the coating layer. Hereinafter, the particles attached to the mica refer to particles attached to the mica directly or via the coating layer. The number of spherical particles attached to a single side of a mica particle may be 1 to 100, for example, 1, 2, 3, 5, 9, 10, 15, 20, 15, 30, 31, 40, 50, 60, 70, 80, 90, 100, or within the range between any two of the values ​​exemplified here. The presence or absence of spherical particles attached to the mica and the number of spherical particles attached to a mica particle can be confirmed by observing the composite powder using an SEM. The average number of spherical particles attached to a single side of a mica particle can be obtained by observing a plurality of micas and dividing the sum of the spherical particles attached to a single side of each mica by the number of particles of the observed mica. Furthermore, part of the spherical particles may not be attached to the mica, and the composite powder according to one embodiment of the present invention may include spherical particles that are not attached to the mica.

[0019] The average particle size of the spherical particles attached to the mica may be less than 10 μm. The average particle size may be 0.1 to 10 μm, for example, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 μm, or may be within the range between any two of the values ​​exemplified herein. In addition, the average particle size of the spherical particles may be measured by SEM observation. The average particle size may be obtained by measuring the particle size of the spherical particles one by one and taking the average value thereof. In addition, the spherical particles attached to the mica may include spherical particles having a particle size of 0.1 μm or more, preferably spherical particles having a particle size of 0.5 μm or more, preferably spherical particles having a particle size of 1.0 μm or more, and preferably include a plurality of particles having such an average particle size. The shape, size and number of attached spherical particles can be controlled by adjusting the type and amount of the water-resistant organic material and the manufacturing conditions of the composite powder, in particular, by adjusting the type and amount of the mica and precursor organic material in the dispersion and the conditions in the spray drying step.

[0020] 1.4 Water-resistant organic materials The coating layer and spherical particles of the present invention are composed of a water-resistant organic material. A water-resistant organic material refers to an organic material that is not easily soluble in water. Specifically, the water-resistant organic material may be an organic material having a solubility of less than 80% by mass when immersed in water at 25°C for 3 days. The solubility of the water-resistant organic material when immersed in water at 25°C for 3 days is, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75% by mass and less than 80% by mass, and may also be within the range between any two of the values ​​exemplified here. From the viewpoint of water resistance that can be used as a cosmetic powder, the solubility of the water-resistant organic material is preferably less than 60% by mass, and particularly preferably less than 20% by mass.

[0021] The solubility when immersed in water at 25°C for 3 days can be calculated by immersing the target material in ion-exchanged water at 25°C for 3 days and using the sample mass Ag before immersion and the residual mass Bg after immersion according to the following formula. [Solubility (mass %)] = (AB) / A×100 In addition, the solubility of the organic material contained in the composite powder can also be evaluated by using the composite powder as an analysis object. In this case, the content (mass %) of mica and water-resistant organic material in the composite powder can be calculated in advance by the method described below, and the composite powder can be immersed in ion exchange water at 25°C for 3 days. The solubility of the organic material contained in the composite powder can be calculated from the mass change before and after immersion and the content of the organic material contained in the composite powder. The solubility of the water-resistant organic material can be controlled by adjusting the type of water-resistant organic material and the manufacturing conditions during the manufacture of the composite powder (the type of precursor organic material prepared in the dispersion, the heating treatment temperature and time).

[0022] The water-resistant organic material preferably has biodegradability. Biodegradability means that the polymer decomposes and disappears in the earth environment such as soil and seawater, and / or decomposes and disappears in the body of an organism. As an example, the water-resistant organic material preferably has a BOD decomposition degree of 60% or more when exposed to activated sludge for 28 days based on OECDTG301C. As another example, the water-resistant organic material preferably has a decomposition degree of 60% or more when buried in soil based on JIS K 6955 (ISO17556), or a relative decomposition degree of 90% or more relative to cellulose. As another example, the water-resistant organic material preferably has a relative decomposition degree of 60% or more relative to cellulose when left standing in seawater and sandy deposits based on ISO19679.

[0023] The water-resistant organic material may be one compound or may contain two or more compounds. The water-resistant organic material may be obtained by using the precursor organic material described later as a raw material and heating the precursor organic material. The water-resistant organic material may be a material that has been subjected to heat treatment to improve the crystallinity and water resistance of the precursor organic material. In addition, specific examples of the water-resistant organic material will be described in the description of the precursor organic material later.

[0024] 1.5 Content of mica and water-resistant organic materials in composite powder The composite powder according to one embodiment of the present invention preferably contains 10 parts by mass or more of a water-resistant organic material, more preferably more than 10 parts by mass of a water-resistant organic material, based on 100 parts by mass of mica in the composite powder. The content of the water-resistant organic material relative to 100 parts by mass of mica is, for example, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1050, 1100, 1150, or 1200 parts by mass, and may be within the range between any two of the numerical values ​​exemplified here. In addition, the content of mica and water-resistant organic material in the composite powder can be calculated by heating the composite powder to a temperature higher than the temperature at which the water-resistant organic material burns out, and from the mass before heating (mica + water-resistant organic material) and the mass after heating (mica).

[0025] The composite powder of one embodiment of the present invention may contain a total of 50 parts by mass or more of mica and water-resistant organic material, for example, 50, 60, 70, 80, 90, 100 parts by mass, relative to 100 parts by mass of the composite powder, or in a range between any two of the values ​​exemplified herein. The composite powder of one embodiment of the present invention may also be composed of mica and a water-resistant organic material.

[0026] The composite powder of one embodiment of the present invention may contain known ingredients used in cosmetics within the range that does not impair the effects of the present invention. Examples of known ingredients include inorganic powders, organic powders, oily ingredients, surfactants, ultraviolet absorbers, moisturizers, anti-fading agents, antioxidants, defoamers, preservatives, fragrances, solubilizers, plasticizers, viscosity modifiers, skin-beautifying ingredients (whitening agents, cell activators, rough skin improvers, blood circulation promoters, skin astringents, anti-seborrheic agents, etc.), vitamins, amino acids, antiperspirants, alcohols, film-forming agents, anti-inflammatory agents, cooling agents, nucleic acids, hormones, inclusion compounds, pH adjusters, chelating agents, etc.

[0027] 2. Physical properties of composite powder The composite powder according to one embodiment of the present invention preferably has the following physical properties.

[0028] 2.1 Average coefficient of friction (MIU) The composite powder of one embodiment of the present invention preferably has an average friction coefficient (MIU) of 0.75 or less, and may be 0.40 to 0.75. The average friction coefficient is, for example, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, or may be in the range between any two of the values ​​exemplified herein. The average friction coefficient can be obtained by applying the composite powder to a skin material such as artificial skin and scanning it using a friction tester. Specifically, it can be measured using the method described in the examples. By making the average friction coefficient above the above lower limit, the uniform state of the cosmetic powder can be maintained after application to the skin, and cosmetics with excellent so-called cosmetic durability can be obtained. In addition, there is little collapse or falling off during or after molding by compression, and the moldability is excellent. If the average friction coefficient is below the above upper limit, a smooth, non-rough, uniformly applied cosmetic can be obtained. The average friction coefficient can be adjusted by the type and structure of the composite powder components, especially by controlling the number and size of the spherical particles attached to the mica.

[0029] 2.2 Soft Focus Factor (SFF) The composite powder of one embodiment of the present invention preferably has a soft focus factor (SFF) of 0.86 or more, and may be 0.86 to 1.40. The soft focus factor is, for example, 0.86, 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.3, 1.35, 1.40, and may also be in the range between any two of the values ​​exemplified here. The soft focus factor can be measured by coating the composite powder on a skin material such as artificial skin and using an angular photometer. The light source can be fixed at 45°, and the sensor can be scanned from 0° to 180° to measure the brightness at each angle, and the ratio of the brightness at the two points (brightness at 65° / brightness at 135°) is used as the soft focus factor. Specifically, the measurement can be performed using the method described in the examples. By making the soft focus factor above the above lower limit, a cosmetic with suppressed glare perception can be obtained. By making the soft focus factor equal to or greater than the above lower limit, the high brightness of mica itself as an extender pigment can be fully utilized to obtain a bright cosmetic. The soft focus factor can be adjusted by the type and structure of the composite powder components. In particular, it can be adjusted by controlling the amount of water-resistant organic material coated on the mica and the number and size of spherical particles.

[0030] 2.3 Solubility of composite powder The composite powder of one embodiment of the present invention preferably has a solubility of 40% by mass or less when immersed in water at 25°C for 3 days. For example, it is 0, 5, 10, 15, 20, 25, 30, 35, or 40% by mass, or it may be in the range between any two of the values ​​exemplified here. The solubility of the composite powder when immersed in water at 25°C for 3 days can be calculated by immersing the composite powder in ion exchange water at 25°C for 3 days, using the mass Ag of the composite powder before immersion and the mass Bg of the residue after immersion according to the following formula. [Solubility (mass %)] = (AB) / A×100 The solubility of the composite powder can be controlled by adjusting the type and amount of the water-resistant organic material and the production conditions (type and amount of the precursor organic material mixed in the dispersion, and the heating treatment temperature and time) during the production of the composite powder.

[0031] The composite powder of one embodiment of the present invention has a low average friction coefficient and a high soft focus coefficient, and can therefore be used in cosmetics. In addition, the composite powder of one embodiment of the present invention has excellent water resistance, and thus can maintain the particle structure unique to the present invention even in an environment containing water, and can maintain the above-mentioned effects. Examples of cosmetics include liquid, gel, solid, and the like, such as foundation, white powder, eye shadow, eyeliner, eyebrow pencil, blush, lipstick, nail polish, and the like.

[0032] 3. Method for manufacturing composite powder The method for producing a composite powder according to one embodiment of the present invention may include a dispersion preparation step, a spray drying step, and a water resistance treatment step. In the dispersion preparation step, a dispersion containing the mica and the precursor organic material is prepared, in the spray drying step, the dispersion is spray dried to obtain a composite powder precursor, and in the heat treatment step, the composite powder precursor is heat treated to convert at least a portion of the precursor organic material into the water-resistant organic material.

[0033] 3.1 Dispersion preparation steps In the dispersion preparation step, a dispersion containing the aforementioned mica and a precursor organic material is prepared. As mica, mica having the aforementioned average particle size and aspect ratio can be used. From the viewpoint of facilitating the formation of a coating layer on the mica and improving the soft focus property, the precursor organic material is preferably an organic material soluble in water. An organic material soluble in water can be uniformly present in a solvent, so it is easy to form a coating layer on the surface of the mica. An organic material soluble in water means that when 1 g of the organic material is dissolved in 100 g of water, no residual organic material is produced. The precursor organic material may be a material having a higher solubility than a water-resistant organic material. Specifically, the precursor organic material may be an organic material having a solubility of 80% by mass or more when immersed in water at 25° C. for 3 days. The solubility of the precursor organic material when immersed in water at 25° C. for 3 days is, for example, 80, 85, 90, 95, 96, 97, 98, 99, 100% by mass, and may also be within the range between any two of the numerical values ​​exemplified here.

[0034] The precursor organic material may be one compound. The precursor organic material may also include two or more compounds. The precursor organic material may also be a mixture of an organic compound that is poorly soluble in water alone and a solubilizing agent that has the function of making the compound soluble in water. In this case, the solubility of the precursor organic material as a mixture when immersed in water at 25° C. for 3 days is preferably 80% by mass or more.

[0035] The precursor organic material preferably has a solubility of less than 80% by mass when heated at 180°C for 30 minutes and then immersed in water at 25°C for 3 days. The solubility of the precursor organic material after heating at 180°C for 30 minutes and immersed in water at 25°C for 3 days is, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75% by mass, and less than 80% by mass, and may also be in the range between any two of the values ​​exemplified here. From the viewpoint of water resistance that can be used as a cosmetic powder, it is preferably 60% by mass or less, and particularly preferably 20% by mass or less. The precursor organic material is preferably dissolved in water to form a uniform dispersion when preparing the dispersion, and preferably has water resistance after the spray drying step and the heat treatment step. The water-resistant organic material can be obtained by heat-treating the precursor organic material (for example, by increasing the crystallinity of the precursor organic material).

[0036] The solubility of the water-resistant organic material when immersed in water at 25° C. for 3 days may be lower than the solubility of the precursor organic material when immersed in water at 25° C. for 3 days. The difference between the solubility of the water-resistant organic material when immersed in water at 25° C. for 3 days and the solubility of the precursor organic material when immersed in water at 25° C. for 3 days is, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 mass %, and may be within the range between any two of the values ​​exemplified here. In addition, the solubility of the composite powder when immersed in water at 25° C. for 3 days may be lower than the solubility of the composite powder precursor when immersed in water at 25° C. for 3 days. The difference between the solubility of the composite powder when immersed in water at 25°C for 3 days and the solubility of the composite powder precursor when immersed in water at 25°C for 3 days is, for example, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50% by mass, or may be within the range between any two of the values ​​exemplified here.

[0037] The precursor organic material preferably has the above-mentioned water solubility and water resistance after heating, and is not particularly limited as long as it has the above-mentioned properties. The precursor organic material may include a water-soluble synthetic polymer and / or a natural polymer.

[0038] Examples of the water-soluble synthetic polymer include polyvinyl alcohol, polyvinyl methyl ether, polyvinyl pyrrolidone, polyacrylic acid, polyalkylene oxide, and polyamino acid, and polyvinyl alcohol (PVA) is preferred. The saponification degree of polyvinyl alcohol (PVA) is preferably 60 mol% or more, more preferably 90 mol% or more. The saponification degree is, for example, 60, 65, 70, 75, 80, 85, 90, 95, 100 mol%, and may be in the range between any two of the values ​​exemplified here. By making the saponification degree above the above lower limit, it is possible to appropriately crystallize during heat treatment to form a water-resistant organic material.

[0039] The weight average molecular weight of PVA may be 5000 to 300000. The weight average molecular weight of PVA may be, for example, 5000, 10000, 50000, 100000, 300000, or may be in the range between any two of the values ​​exemplified herein. When the weight average molecular weight is within the above numerical range, the dispersion has a viscosity suitable for spray drying, and the shape of the spherical particles in the obtained composite powder is closer to a perfect sphere and has fewer bumps.

[0040] As natural polymers, polysaccharides and salts thereof can be cited. Polysaccharides can include glucosamine series and molecules containing glucose units. Glucosamine series can include chitosan as β-1,4-glucosamine. In addition, chitin as β-1,4-N-acetylglucosamine can be cited. Molecules containing glucose units can include β-glucans. β-glucans can include β-1,4-glucans and β-1,3-glucans. As β-1,4-glucans, cellulose, cellulose acetate, ethyl cellulose, methyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl methyl cellulose can be cited. Among them, from the viewpoint of improving crystallinity during heating, carboxymethyl cellulose and hydroxyethyl cellulose are more preferred. As β-1,3-glucans, curdlan and paramylon can be cited. In addition, alginic acid as a block polymer of β-D-mannuronic acid and α-L-guluronic acid can be cited. Crystalline cellulose and keratin have low solubility in water and cannot improve the soft focus factor, so they are not preferred. The precursor organic material of one embodiment of the present invention may not contain crystalline cellulose and keratin. In addition, the water-resistant organic material of one embodiment of the present invention may not contain crystalline cellulose and keratin.

[0041] When these compounds are insoluble in water alone, they can also be used together with solubilizing agents such as acids and bases. As an example, chitosan is preferably used together with acetic acid as a solubilizing agent, and curdlan can be used together with ammonia water as a solubilizing agent. At this time, the precursor organic material can contain 1 to 300 parts by mass of a solubilizing agent relative to 100 parts by mass of compounds such as chitosan or curdlan. The content of the solubilizing agent is, for example, 0, 50, 100, 150, 200, 250, 300 parts by mass, or it can be within the range between any two of the numerical values ​​exemplified here.

[0042] As the solvent of the dispersion liquid, water, an organic solvent, or a mixed solvent of water and an organic solvent can be cited, wherein water is preferably contained, and water is more preferably contained. Examples of water include natural water, purified water, distilled water, ion exchange water, pure water, etc., wherein ion exchange water is preferred. As the organic solvent, examples include aliphatic monohydric alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, aromatic compounds such as toluene and xylene, etc., and for example, a mixed solvent of water and an organic solvent can also be cited.

[0043] The dispersion may be a dispersion obtained by dispersing and / or dissolving mica and a precursor organic material in a solvent. The concentration of mica in the dispersion may be 0.1 to 70% by mass. The concentration of mica is, for example, 0.1, 0.5, 1, 5, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70% by mass, or in the range between any two of the values ​​exemplified herein. The concentration of the precursor organic material in the dispersion may be 0.05 to 35% by mass. The concentration of the precursor organic material is, for example, 0.05, 0.1, 0.5, 1, 5, 0, 5, 10, 15, 20, 25, 30, 35% by mass, or in the range between any two of the values ​​exemplified herein.

[0044] The dispersion preferably contains 10 parts by mass or more of the precursor organic material, more preferably more than 10 parts by mass of the precursor organic material, relative to 100 parts by mass of the mica. The content of the precursor organic material relative to 100 parts by mass of the mica in the dispersion is, for example, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1050, 1100, 1150, 1200 parts by mass, and may be in the range between any two of the numerical values ​​exemplified here. By adjusting the type and amount of mica and precursor organic material in the dispersion, the structure and physical properties of the obtained composite powder can be adjusted. For example, by making the concentration of the precursor organic material in the dispersion sufficiently high and the content of the precursor organic material relative to the mica sufficiently high, a composite powder can be obtained in which the mica is fully coated, a sufficient number and size of spherical particles are attached to the mica, the average friction coefficient is low, and the soft focus coefficient is high.

[0045] The viscosity of the dispersion is preferably 1 Pa·s or less. By setting such a viscosity, it is easy to obtain a composite powder with a structure in which mica is coated with a precursor organic material and spherical particles are attached to the mica. In the dispersion preparation step, a treatment for adjusting the viscosity and rheology of the dispersion can be performed as needed. For example, the treatment for reducing the viscosity, especially the dynamic viscosity under high shear force, and the treatment for imparting pseudoplasticity and thixotropy can be listed. As an example, these treatments can be performed by adding a dispersant and reducing the molecular weight of the organic material.

[0046] The dispersion can be prepared by stirring with a known stirrer, for example, a dispersing mixer, a homomixer, a high-pressure homogenizer, etc. can be used.

[0047] 3.2 Spray drying step In the spray drying step, the dispersion is spray dried to obtain a composite powder precursor. The composite powder precursor of the present invention is a composite powder precursor comprising mica, a coating layer, and spherical particles, wherein the mica is coated with the coating layer, the coating layer and the spherical particles contain a precursor organic material, and the spherical particles are attached to the mica or the coating layer.

[0048] In the spray drying step, the composite powder precursor can be obtained by supplying the dispersion to a spray dryer (spray dryer) adjusted to a predetermined temperature and spraying. The spray dryer is not particularly limited as long as it is a spray dryer commonly used in granulation production. The spray dryer may include: ·Raw material tank for storing dispersion liquid, ·Raw material supply pump for supplying dispersion liquid, Nozzles (four-fluid nozzles, two-fluid nozzles or single-fluid nozzles) or rotating disks that make the dispersion into fine droplets, Drying chamber for drying and granulating the droplets, Blowers, filters, heaters, and other equipment used to blow dry and heated air or inert gas into the drying chamber. A collector for recovering the composite powder precursor by a two-point collection method, a cyclone method, a bag filtration method, etc. (these collectors may also be heatable collectors), etc. By adjusting the droplet formation conditions and drying conditions in the spray drying step, the structure and physical properties of the obtained composite powder can be adjusted.

[0049] In the spray drying step, the outlet temperature of the spray dryer may be 70 to 250°C. The outlet temperature may be, for example, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250°C, or may be in the range between any two of the values ​​exemplified herein. In addition, in the spray drying step, a portion of the precursor organic material in the obtained composite powder precursor may become a water-resistant organic material. In addition, in the spray drying step, for example, by adjusting the drying conditions after granulation, further providing a heating function in the spray dryer, or a heating chamber that can be heated and maintained for a certain period of time, it may also serve as the heating treatment step described later.

[0050] 3.3 Heating treatment steps In the heating step, the composite powder precursor is subjected to a heating treatment to convert at least a portion of the precursor organic material into the water-resistant organic material.

[0051] The heating temperature in the heat treatment step may be 100 to 300° C. The heating temperature may be, for example, 100, 110, 120, 140, 160, 180, 200, 220, 240, 260, 280, or 300° C., or may be in a range between any two of the values ​​exemplified here. The heating time in the heat treatment step may be 10 to 300 minutes. The heating time may be, for example, 10, 20, 30, 40, 40, 60, 70, 80, 90, 100, 110, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300 minutes, or may be within a range between any two of the values ​​exemplified herein.

[0052] During the heating treatment step, the water resistance of the organic compound contained in the precursor organic material is improved. The mechanism for improving water resistance is not particularly limited. In general, there are known methods for improving water resistance by forming a cross-linked structure using a cross-linking agent, and methods for improving water resistance by modifying the entire material or the surface of the material. However, when the water resistance is improved by these methods, the biodegradability of the obtained water-resistant organic material may deteriorate. In one embodiment of the present invention, for example, by improving the crystallinity of the organic compound contained in the precursor organic material, the water resistance of the precursor organic compound can be improved (reducing solubility). At this time, a material containing a crystalline molecule is used as the precursor organic material, and the crystallinity is improved by heating to form a firm state in which the target molecules are more tightly hydrogen-bonded to each other, thereby improving water resistance.

[0053] In the manufacturing method of one embodiment of the present invention, unlike the previous manufacturing method of a composite powder containing plate-like particles and spherical particles, there is no need to go through the steps of separately preparing spherical particles or separately polymerizing spherical particles. The steps of coating mica with organic materials and forming spherical particles and attaching them to mica can be performed in the same step. Therefore, the manufacturing steps are simple and have great advantages in terms of cost, labor, and less equipment required. [Example]

[0054] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[0055] (Example 1) <Dispersion Preparation Step> Mica (average particle size 20 μm) and PVA (manufactured by JAPAN VAM & POVAL CO., LTD., 10HH, saponification degree 98.5% or more, polymerization degree 240, molecular weight about 10,000) were added and mixed in water to prepare a dispersion having a mica concentration of 30% by mass and a PVA concentration of 15% by mass.

[0056] <Spray Drying Step> A two-fluid nozzle laboratory spray dryer was used and the inlet temperature of the spray dryer was set to 140° C. to 200° C. to perform spray drying.

[0057] <Heat treatment step> The obtained composite powder precursor was heated at 180° C. for 30 minutes in an air environment to obtain composite powder 1.

[0058] As shown in the SEM observation results described later, it was confirmed that in the composite powder 1, the mica was coated with PVA, and spherical particles were attached to both main surfaces of the mica, and 10 to 30 spherical particles were attached to one surface of one mica particle (see Figure 1 ). In addition, the mass ratio of mica and PVA constituting the composite powder precursor 1 is confirmed by the following method. First, the composite powder precursor 1 after the spray drying step is dispersed in hot water, and the spherical particles composed of the PVA coating the mica and the PVA attached to the mica are dissolved again in hot water and filtered by suction. Then, the residue on the filter paper is dried and weighed, and the amount of mica constituting the composite powder precursor 1 is calculated. Then, the amount of mica is subtracted from the mass of the composite powder precursor 1 before being dissolved in hot water, and the amount of PVA constituting the composite powder precursor 1 is calculated. As a result, it was confirmed that the mass ratio of mica and PVA constituting the composite powder precursor 1 was approximately 2:1 (=30:15), which was the same as the added amount.

[0059] (Examples 2 to 19, Comparative Examples 1 to 2, 5) The dispersion preparation, spray dryer and heat treatment conditions were changed as described in Tables 1 to 3 to obtain composite powders 2 to 21 and 24.

[0060] (Comparative Example 3) <Dispersion Preparation Step> PVA (manufactured by JAPAN VAM & POVAL CO., LTD., 10HH, saponification degree 98.5% or more, polymerization degree 240, molecular weight about 10000) was added to water and mixed to prepare a dispersion having a PVA concentration of 15% by mass.

[0061] <Spray Drying Step> Spray drying was performed using a two-fluid nozzle laboratory spray dryer with the inlet temperature of the spray dryer set to 140° C. to 200° C. The measured values ​​of the outlet temperature are shown in the table.

[0062] <Heat treatment step> The obtained composite powder precursor was heated at 180° C. for 30 minutes in an air environment to obtain spherical particles 22 .

[0063] <Powder mixing step> 15 parts by mass of the obtained spherical particles 1 and 30 parts by mass of mica were mixed to obtain a composite powder 22 .

[0064] (Comparative Example 4) The dispersion preparation step, the spray drying step, and the heat treatment step were performed in the same manner as in Comparative Example 3 to obtain spherical particles 23 . In the powder mixing step, 15 parts by mass of the obtained spherical particles 1 and 15 parts by mass of mica were mixed to obtain a composite powder 23 .

[0065] The raw materials used in the preparation of the dispersion are as follows. Natural mica: average particle size 20μm PVA (polyvinyl alcohol) 10HH: Made by JAPAN VAM&POVAL CO., LTD., 10HH, saponification degree 98.5% or more, polymerization degree 240, molecular weight about 10000 PVA (polyvinyl alcohol) PVA117: Kuraray Co., Ltd., PVA117, saponification degree over 98.0%, polymerization degree 1700, molecular weight about 76000 PVA (polyvinyl alcohol) 500HH: Made by JAPAN VAM&POVAL CO., LTD., 500HH, saponification degree 98.5% or more, polymerization degree 5000, molecular weight about 222000 β-1,4-glucosamine (chitosan): Koyo Chemical Co., Ltd., KOYO Chitosan FL-80, deacetylation degree 75% or more β-1,4-glucan CMC-NH4 (ammonium carboxymethyl cellulose): Nichirin Chemical Industries, Ltd., KICCOLATE NA-3L β-1,4-glucan MC (methylcellulose): Shin-Etsu Chemical Co., Ltd., METOLOSE SM-4 β-1,4-glucan HEC(hydroxyethyl cellulose): SanJing Co., Ltd., SANHEC L β-1,4-glucan HPMC (hydroxypropyl methylcellulose): Shin-Etsu Chemical Co., Ltd., METOLOSE60SH-03 β-1,3-glucan: Mitsubishi Corporation Life Sciences Co., Ltd., CURDLAN Alginic acid: KIMICA Co., Ltd., Kimica Acid G Cellulose fiber: Evonik Japan Co., Ltd., TEGO Feel C10

[0066] (Evaluation of composite powder) <Structure> The obtained composite powder was observed using SEM to observe the structure of the composite powder, and the average number of spherical particles attached to a single side of a mica particle was evaluated according to the following evaluation criteria. An appropriate amount of composite powder was applied to the carbon tape, and a conductive treatment was performed to prepare the sample. The image was taken at a magnification of 1000 to 4000 times using a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, model: Regulus8230) so that one mica was included in one picture, and the number of spherical particles attached to a single side of the mica was counted. Similarly, in the other two fields of view, the image was taken at a magnification of 1000 to 4000 times so that one mica was included in one picture, and the number of spherical particles attached to a single side of the mica was counted. The observation site was a place about 1 mm away from each other. The mica in three fields of view was observed, and the average number of spherical particles attached to a single side of a mica particle was calculated, and evaluated according to the following evaluation criteria. The results are shown in Tables 1 to 3.

[0067] The presence and quantity of spherical particles ◎: More than 31 spherical particles are attached to one side of a mica particle ○: 10 to 30 spherical particles are attached to one side of a mica particle △: One mica particle has 1 to 9 spherical particles attached to one side. ×: No spherical particles are attached to mica

[0068] In addition, the presence or absence of a coating layer on mica was confirmed by the following method: First, composite powders for confirming the coating layer were prepared for each composite powder of Examples and Comparative Examples.

[0069] (Preparation of composite powder for confirming coating layer) A dispersion was prepared in the same manner as in the method for producing each composite powder of each example and comparative example except that mica was not added, and a spray drying step was performed to obtain resin particles. Thereafter, the obtained resin particles were composited with the same amount of mica as in each composite powder of each example and comparative example to obtain a composite powder for confirming a coating layer composed of mica without a coating layer and resin particles.

[0070] (Confirmation of the presence or absence of coating) Disperse 5 g of the composite powder of each embodiment and comparative example, and the composite powder used to confirm the coating layer of each embodiment and comparative example in 50 g of solvent (isopropyl alcohol). Pass each dispersion through a 200-mesh sieve. Here, the resin particles attached to the mica in the dispersion are separated from the mica and pass through the sieve holes, while the mica remains on the sieve. Recover the residue on the 200-mesh sieve, dry it in a dryer at 100°C for 3 hours to obtain a dried product, and weigh each dried product. The mass difference between the dried product of the composite powder of each embodiment and comparative example and the dried product of the composite powder used to confirm the coating layer of each embodiment and comparative example is taken as the coating amount of mica, and evaluated according to the following evaluation criteria. ○: The dried composite powder is heavier than the dried composite powder for confirming the coating layer, and the difference is 5% by mass or more of the mass of the dried composite powder for confirming the coating layer. ×: The dried composite powder is heavier than the dried composite powder for confirming the coating layer, but the difference is less than 5% by mass of the dried composite powder for confirming the coating layer. Or the dried composite powder is of the same mass as the dried composite powder for confirming the coating layer.

[0071] <Average Friction Coefficient (MIU)> The obtained composite powder was 1 mg / cm 2 The coating was applied to artificial skin (Beaulax), and the friction coefficient was measured by using a friction tester KES at a load of 50N and a speed of 1mm / s to scan 30mm. The average value of the central 20mm was taken as the average friction coefficient (MIU). The results are shown in Tables 1 to 3.

[0072] <Soft Focus Factor (SFF)> The obtained composite powder was 10 mg / cm 2 The soft focus coefficient was evaluated by applying it on artificial skin (Beaulax) using a goniophotometer (GC-5000L, Nippon Denshoku Industries Co., Ltd.). Specifically, the light source was fixed at a 45° position, and the sensor was made to scan the surface of the artificial skin coated with the composite powder from 0° to 180°, and the brightness at each angle was measured, and the ratio of the brightness at two points (brightness at 65° / brightness at 135°) was used as the soft focus coefficient. The results are shown in Tables 1 to 3.

[0073] <Solubility of organic materials after heat treatment (immersion in water at 25°C for 3 days)> The precursor organic material used in the manufacture of the composite powder of each embodiment and comparative example was heat-treated under the same conditions as those of each embodiment and comparative example, and used as a sample for solubility evaluation. First, 1 g of the sample was immersed in 10 g of ion exchange water at 25°C for 3 days. Thereafter, the mixture was suction filtered using a glass fiber filter, and the residue captured on the filter was dried in a dryer at 100°C for 2 hours, and the mass of the residue was calculated. The mass of the sample before immersion was set as Ag, and the mass of the residue was set as B g. The solubility of each sample was calculated by the following formula, and evaluated according to the following evaluation criteria. The results are shown in Tables 1 to 3. [Solubility (mass %)] = (AB) / A×100 ◎: 20% by mass or less ○: more than 20% by mass and less than 60% by mass △: more than 60 mass % and less than 80 mass % ×: 80 mass % or more

[0074] In addition, the solubility of unheated PVA (polyvinyl alcohol) 10HH is 85 mass%, the solubility of PVA (polyvinyl alcohol) PVA117 is 85 mass%, the solubility of PVA (polyvinyl alcohol) 500HH is 80 mass%, the solubility of a mixture of chitosan and acetic acid in a 1:1 ratio is 100 mass%, the solubility of CMC-NH4 (ammonium carboxymethylcellulose) is 100 mass%, the solubility of MC (methylcellulose) is 100 mass%, the solubility of HEC (hydroxyethyl cellulose) is 100 mass%, the solubility of HPMC (hydroxypropyl methylcellulose) is 100 mass%, the solubility of a mixture of curdlan and ammonia water (5 mass%) in a 1:1 ratio is 100 mass%, the solubility of a mixture of alginic acid and acetic acid in a 1:1 ratio is 100 mass%, and the solubility of cellulose fiber is 0 mass%.

[0075] [Table 1]

[0076] [Table 2]

[0077] [Table 3]

Claims

1. A composite powder comprising mica, a coating layer, and spherical particles, The coating layer covers the mica, The spherical particles are attached to the mica or the coating layer, The coating layer and the spherical particles are made of a water-resistant organic material.

2. The composite powder according to claim 1, Its average friction coefficient is below 0.

75. The soft focus factor is above 0.

86.

3. The composite powder according to claim 1 or 2, wherein The water-resistant organic material is contained in an amount of 10 parts by mass or more based on 100 parts by mass of the mica. The composite powder according to claim 1 or 2, which is used in cosmetics.

5. A method for producing a composite powder, which is a method for producing the composite powder according to claim 1 or 2, the method comprising a dispersion preparation step, a spray drying step, and a heating treatment step, In the dispersion preparation step, a dispersion containing the mica and a precursor organic material is prepared. In the spray drying step, the dispersion is spray dried to obtain a composite powder precursor, and in the heat treatment step, the composite powder precursor is heat treated to convert at least a portion of the precursor organic material into the water-resistant organic material.

6. The manufacturing method according to claim 5, wherein: The solubility of the precursor organic material when immersed in water at 25° C. for 3 days is higher by 5% by mass or more than the solubility of the water-resistant organic material when immersed in water at 25° C. for 3 days.

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