JPH09328412A - Bulk powder for cosmetic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a colored powder which is useful as a raw material for cosmetics having stabilized colors of blue, green, yellow or the like in no need of dyes and pigments by forming multi-layers of thin films different in refractive index on the surface of powdery nuclear particles and adjusting the form of interfacial waves of the reflection light in the multi-layer film. SOLUTION: On the surface of powdery nuclear particles 1, a plurality of coating layers 2, 3 different in refractive index are formed. As the powdery nuclear particles, are prelerably an organic substance, for example, spherical acrylic resin particles. The material constituting the coating layers may be arbitrarily selected from inorganic metal compounds, metals or their alloys and organic substances. The inorganic metal compounds are, for example, oxides or multiple oxides of Fe, Ni, Cr or the like, or iron nitride. The elementary metal is, for example, metallic silver, metallic cobalt or the like. The metal alloy is, for example, iron-nickel alloy, iron-cobalt alloy or the like. As an orgtrnic substance, are cited cellulose, polyamide and the like. The particle size of this powder is 0.01μm to several mm. The bulk powder particles of this cosmetic can maintain clear colors for a long period of time.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cosmetic raw material powder.

[0002]

2. Description of the Related Art The present inventors have previously proposed a metal or a metal compound in order to provide a powder having a composite function which has other properties in addition to the properties of only the metal particles or the metal compound particles. The surface of the powder core particles has a uniform 0.01 to
A powder having a thickness of 20 μm and having a metal oxide film containing a metal different from the metal constituting the powder core particles has been invented (Japanese Patent Application Laid-Open No. 6-228604). Further, the present inventors have further improved the above-mentioned powder, and invented not only a metal oxide film alone but also a powder having a plurality of metal oxide films and metal films alternately (see JP-A-7-1995). -90310).

In order to produce these powders, it is necessary to provide a plurality of metal oxide films having a uniform thickness on the powder core particles. For that purpose, from the metal salt aqueous solution to the metal oxide film. Or, since it is difficult to precipitate a metal compound that is a precursor thereof, the present inventors have dispersed the powder in a metal alkoxide solution and hydrolyzed the metal alkoxide to form a powder on the powder. We have developed a method for forming metal oxide films, which enables the formation of thin and uniform metal oxide films, and in particular enables the formation of multi-layer metal oxide films. Became.

[0004]

However, since the powder having a metal or metal compound as a core has a large specific gravity, it tends to settle in the liquid, and it is difficult to settle and separate to make the powder uniform, which makes it difficult to use as a cosmetic raw material, particularly as an emulsion cosmetic raw material. Is difficult to use. Further, for example, when particles of titanium oxide or the like are attached to the surface of the resin powder, there is a problem that the powder particles may peel off from the coating shell on the surface during use, which may change the color. An object of the present invention is to provide a light powder color cosmetic raw material in which these problems are solved.

[0005]

As a result of intensive studies, the inventors of the present invention have adjusted the reflected light interference waveform of a multilayer film by forming a multilayer thin film having different refractive indexes on the surface of powder core particles. The inventors have found that a colored powder having a stable color tone such as blue, green and yellow can be obtained without using a dye or a pigment, and have completed the present invention.

That is, the cosmetic raw material powder of the present invention is characterized by having a plurality of coating layers having different refractive indexes on the surface of powder core particles having a specific gravity of 0.3 to 2.8.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the powder core particles having a specific gravity of 0.3 to 2.8 forming the core of the cosmetic raw material powder are not particularly limited, and may be organic or inorganic.
However, from the viewpoint of easy availability and preparation, organic substances are preferable, and more specifically, resin particles are preferable. Specific examples of the resin particles, cellulose powder, cellulose acetate powder, polyamide, epoxy resin, polyester, melamine resin, polyurethane, vinyl acetate resin, silicon resin, acrylic ester, methacrylic ester, styrene,
Examples thereof include spherical or crushed particles obtained by polymerizing or copolymerizing ethylene, propylene and their derivatives. Particularly preferred resin particles are spherical acrylic resin particles obtained by polymerization of acrylic acid or methacrylic acid ester. Examples of the inorganic substance include inorganic hollow particles such as shirasu balloon (hollow silicate particles), minute carbon hollow spheres (crecassphere), fused alumina bubbles, aerosil, white carbon, silica minute hollow spheres, calcium carbonate minute hollow spheres, calcium carbonate. , Perlite, talc, bentonite, kaolin and the like can be used.

In the cosmetic raw material powder of the present invention, the plurality of coating layers formed on the surface of the powder core particles having a specific gravity of 0.3 to 2.8 must have different refractive indexes. It is desirable that the material forming these coating layers is arbitrarily selected from inorganic metal compounds, metals or alloys, and organic substances.

Typical examples of the inorganic metal compound constituting the coating layer include metal oxides, and specific examples thereof include iron, nickel, chromium, titanium, aluminum, silicon, calcium, magnesium and barium. Examples thereof include oxides and composite oxides thereof. Furthermore, examples of metal compounds other than metal oxides include metal nitrides such as iron nitrides and metal carbides.

Examples of the simple metal constituting the coating layer include metallic silver, metallic cobalt, metallic nickel, metallic iron, and the like. Examples of the metallic alloy are iron / nickel alloy, iron / cobalt alloy, iron / nickel alloy nitride, and iron. -Nickel-cobalt alloy nitrides are included.

The organic substance constituting the coating layer may be the same or different from the above-mentioned organic substance constituting the core, and is not particularly limited, but is preferably a resin. Specific examples of the resin, cellulose, cellulose acetate, polyamide, epoxy resin, polyester, melamine resin,
Examples include polyurethane, vinyl acetate resin, silicon resin, acrylic acid ester, methacrylic acid ester, styrene, ethylene, propylene and a polymer or copolymer of these derivatives.

As described above, various materials can be used as the material for forming the coating layer. However, as long as the powder of the present invention is a raw material for cosmetics, it goes without saying that the material for forming the outermost coating layer. Must be inert to living organisms or at least have no adverse effect. A typical example of such a material is titanium dioxide. Further, it can be said that titanium dioxide is effective because it has a property of specifically absorbing UV waves. Further, by using a metal film and a titanium oxide film and controlling the film thickness appropriately, it is possible to obtain a powder having a high reflectance in the entire infrared region, and it is also possible to obtain a UV and IR cut cosmetics. .

The particle size of the cosmetic raw material powder of the present invention is not particularly limited and can be appropriately adjusted according to the purpose.
Usually, it is in the range of 0.01 μm to several mm.

Further, each unit coat layer constituting the plurality of coat layers is set such that each unit coat layer has a specific interference reflection peak or interference transmission bottom at the same wavelength. desirable. More preferably, the thickness of each unit coating layer is set by the following equation (1): N × d = m × λ / 4 (1) [where N is a complex refractive index, d is a basic thickness, and m is Integer (natural number), λ represents the wavelength of the interference reflection peak or the interference transmission bottom, and N is the following equation (2): N = n + iκ (2) (n is the refractive index of each unit coating layer, i is a complex number, κ Represents a damping coefficient)], and each unit is obtained from a function consisting of a phase shift due to a refractive index attenuation coefficient κ, a phase shift at a film interface, a dispersion of a refractive index, and a peak shift depending on a particle shape. The actual thickness of each unit coating layer is corrected so that the coating layer has the interference reflection peak or the interference transmission bottom of the specific wavelength.

As a method for forming the film, the following methods can be mentioned depending on the substance to be formed.
Other methods can be used. (1) When forming an organic film (resin film) a. Polymerization method in liquid phase Dispersing the core particles and emulsion polymerization,
A method of forming a resin film on the particles can be used. b. Film formation method in vapor phase (CVD) (PVD)

(2) When forming an inorganic metal compound film a. Solid phase deposition method in liquid phase A method of dispersing particles serving as nuclei in a metal alkoxide solution and hydrolyzing the metal alkoxide to form a metal oxide film on the particles is preferable. An oxide film can be formed. Further, a metal oxide film or the like can be formed on the particles by the reaction of the aqueous metal salt solution. b. Film forming method in gas phase (CVD) (PVD) (3) When forming metal film or alloy film a. Method of Reducing Metal Salt in Liquid Phase A so-called chemical plating method of reducing a metal salt in an aqueous solution of a metal salt to deposit a metal to form a metal film is used. b. Film formation method in gas phase (CVD) (PVD) A metal film can be formed on the surface of particles by vacuum evaporation of metal or the like.

Next, as an example, a method for forming an alternating multilayer film of a metal oxide having a high refractive index and a metal oxide having a low refractive index will be specifically described. First, powder core particles are dispersed in an alcohol solution in which an alkoxide such as titanium or zirconium is dissolved, and a mixed solution of water, alcohol, and a catalyst is dropped with stirring, and the alkoxide is hydrolyzed. A titanium oxide film or a zirconium oxide film is formed as a high refractive index film on the surface. Thereafter, the powder is subjected to solid-liquid separation, dried and then subjected to a heat treatment.
The drying means may be any of vacuum heating drying, vacuum drying, and natural drying. Further, it is also possible to use a device such as a spray dryer in an inert atmosphere while adjusting the atmosphere. In the heat treatment, a film composition that does not oxidize is in the air, and a film composition that is easily oxidized is in an inert atmosphere,
00 ° C (when the powder core particles are inorganic powder) or 150 to
1 minute at 500 ° C (when the powder core particles are other than inorganic powder)
Heat-treat for 3 hours. Next, while the metal alkoxide having a low refractive index when it becomes an oxide, such as silicon alkoxide and aluminum alkoxide, is dissolved in an alcohol solution, the powder having the high refractive index film is dispersed and stirred. A mixed solution of water, alcohol and a catalyst is dropped and the alkoxide is hydrolyzed to form a silicon oxide or aluminum oxide film as a low refractive index film on the powder surface. Thereafter, the powder is subjected to solid-liquid separation, dried under vacuum, and then subjected to heat treatment in the same manner as described above. By this operation, a powder having two layers of a high-refractive index metal oxide film and a low-refractive index metal oxide film on the surface of the powder is obtained. Further, by repeating the operation of forming this metal oxide film, a powder having a multi-layered metal oxide film on its surface can be obtained. At that time, as described above, by using a powder in which a high-refractive-index metal oxide film and a low-refractive-index metal oxide film are alternately provided, a powder having a high reflectance is obtained, The powder has high whiteness.

As the means for providing the metal film on the surface of the powder core particles or the metal oxide film, the electroless plating method may be used, the contact electroplating method may be used, and the sputtering method may be used. However, in the contact electroplating method, when the powder does not contact the electrode, it is not plated, and in the sputtering method,
The metal vapor does not hit the powder uniformly, and in each method, the film thickness of each powder is different. On the other hand, the film formation method by electroless plating is preferable because a dense and uniform film can be formed and the film thickness can be easily adjusted. Further, the metal film is preferably heat-treated after the film formation, like the metal oxide film.

The present invention will be described in more detail below with reference to the drawings. FIG. 1 is a cross-sectional view showing a conceptual structure of a cosmetic raw material powder of the present invention.
As the core, and two coating layers 2 and 3 having different refractive indexes are provided on the surface thereof.

Further, a special function can be given by adjusting the thickness of each layer of the alternate coating films having different refractive indexes formed on the surface of the powder core particles. For example, an alternating coating film having a different refractive index is formed on the surface of powder core particles by the following formula (1).
When a suitable thickness and number of alternating films having a refractive index n of a substance forming the film and a thickness d corresponding to an integer m times 1/4 of the wavelength of visible light are provided so as to satisfy a specific wavelength, The light of λ (using the interference reflection of Fresnel) is reflected or absorbed. nd = mλ / 4 (1) By utilizing this action, an oxide film having a film thickness and a refractive index satisfying the formula (1) for the target wavelength of visible light on the surface of the powder core particles The film having a reflection or absorption wavelength width peculiar to the visible light region is formed by repeating the steps of forming a film and coating an oxide film having a different refractive index thereon once or more alternately. At this time, the order of the materials to be formed is determined as follows. First, when the refractive index of a core organic substance is high, the first layer is a film having a low refractive index,
In the case of the opposite relationship, the first layer is preferably a film having a high refractive index.

The film thickness is measured and controlled by a spectrophotometer or the like as a reflected waveform by changing the optical film thickness, which is the product of the film refractive index and the film thickness, so that the reflected waveform finally becomes the required waveform. Design the film thickness of each layer. For example, as shown in FIG. 2, when the peak position of the reflection waveform of each unit coating constituting the multilayer film is displaced, white powder is obtained, while as shown in FIG. 3, the peak of the reflection waveform of each unit coating is shown. If you align the position precisely,
A colored powder of a single color such as blue, green and yellow can be obtained without using a dye or pigment.

However, in the case of an actual powder, the particle size of the powder,
It is necessary to design in consideration of the shape, the phase shift at the interface between the film material and the nuclear particle material, and the peak shift due to the wavelength dependence of the refractive index. For example, when the shape of the core particles is a parallel plate shape, the Fresnel interference due to the parallel film formed on the particle plane is expressed by the following formula (2)
The design is performed under the condition that N is replaced. In particular, when the metal film is included even when the shape of the powder is a parallel plate,
The attenuation coefficient κ is included in the refractive index N of the metal in the formula (2). In the case of a transparent oxide (dielectric), κ is very small and can be ignored. N = n + iκ (i represents a complex number) (2) If this damping coefficient κ is large, the phase shift at the mutual interface between the film substance and the nuclear particle substance becomes large, and further, due to the phase shift in all layers of the multilayer film. Interference affects the optimum film thickness.

As a result, the peak position shifts even if only the geometrical film thicknesses are combined, so that the color becomes light, especially when it is colored in a single color. In order to prevent this, the effects of the phase shift on all the films are taken into consideration, and a computer simulation is designed so that the combination of the film thicknesses is optimized in advance.

Further, there is a phase shift due to the oxide layer on the metal surface and a peak shift due to the wavelength dependence of the refractive index. To correct these, use a spectrophotometer, etc.
It is necessary to find the optimum conditions so that the reflection peak and the absorption bottom have the target wavelength at the final target film number.

The interference of a film formed on a curved surface such as a spherical powder occurs like a flat plate, and basically follows the Fresnel interference principle. Therefore, the coloring method can be designed to be white or a single color as shown in FIGS. However, in the case of a curved surface, light incident on and reflected by the powder causes complicated interference. These interference waveforms are almost the same as a flat plate when the number of films is small. However, as the total number increases, the interference inside the multilayer becomes more complicated. Also in the case of a multilayer film, the reflection spectral curve can be designed in advance by computer simulation based on the Fresnel interference so that the combination of the film thickness is optimized. In particular, in the case of forming a film on the surface of the powder core particles, the effect of the phase shift on the surface of the powder core particles and all the films is taken into consideration, and a computer simulation is designed to optimize the combination of film thickness in advance. further,
The peak shift due to the oxide layer on the surface of the powder core particles and the peak shift due to the wavelength dependence of the refractive index are also taken into consideration. In actual sample production, refer to the designed spectral curve and correct these in the actual film by changing the film thickness using a spectrophotometer etc. so that the reflection peak and the absorption bottom become the target wavelength with the final target film number. Optimal conditions must be found. Even in the case of coloring an irregularly shaped powder, interference by the multilayer film occurs, and a basic film design is performed with reference to the conditions of the interference multilayer film of the spherical powder. The peak position of each unit film constituting the above-mentioned multilayer film can be adjusted by the film thickness of each layer, and the film thickness can be adjusted by the solution composition and the reaction time and the number of additions of the raw materials, and the desired color can be obtained. be able to. As described above, white and monochromatic powders can be obtained by finding the optimum conditions while changing the film forming conditions such as the film forming solution so that the reflection peak and the absorption bottom become the target wavelength at the final target film number. it can. Further, by controlling the combination of the substances constituting the multilayer film and the thickness of each unit film, it is possible to adjust the color development due to the interference of the multilayer film. Thus, the powder can be vividly colored to a desired color without using a dye or a pigment.

[0026]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to this embodiment.

Example 1 (1st layer titania coating) 250 ml of ethanol was added to 10 g of acrylic powder (average particle size 1.5 μm) and dispersed, and the container was heated in an oil bath to a temperature of 5
It was kept at 5 ° C. Titanium isopropoxide 3.5
g was added and stirred. Further, 30 ml of ethanol and water 3.
5 g of the mixed solution was added dropwise over 60 minutes, reacted for 2 hours, diluted and washed with a sufficient amount of ethanol, and then dried at 180 ° C. for 8 hours in a vacuum dryer. After drying, titania-coated powder A ₁ was obtained. Obtained titania-coated powder A ₁
Had good dispersibility and each was a single particle. The peak wavelength of the spectral reflection curve of this powder is 455 nm,
The reflectance at the peak wavelength was 32%, which was a light blue color.

(Second layer polystyrene coating) 100 g of styrene monomer was added to 600 g of distilled water, and the temperature was changed to 70 ° C.
While heating and stirring, sodium lauryl sulfate was added and emulsified. To this, 25 g of titania-coated powder A ₁ was mixed, stirred at high speed, and mixed well. An aqueous solution of ammonium persulfate (10%) was added to this to initiate the polymerization reaction, and the reaction was stirred for 4 hours. After completion of the reaction, the mixture was diluted with 2 liters of distilled water, the upper liquid was discarded by gradient washing, and the precipitate was collected. The precipitate is dried on filter paper and polystyrene-titania coated powder A
Got _two . The obtained polystyrene-titania-coated powder A ₂ had good dispersibility and was a single particle.

(Third-layer titania coating) 250 ml of ethanol was added to 10 g of polystyrene-titania-coated powder A ₂ and dispersed, and the container was heated in an oil bath to maintain the temperature of the liquid at 55 ° C. To this, 3.4 g of titanium isopropoxide was added and stirred. 30 more ethanol
A mixed solution of ml and water (3.4 g) was added dropwise over 60 minutes, reacted for 2 hours, diluted and washed with a sufficient amount of ethanol, and then dried at 180 ° C. for 8 hours in a vacuum dryer. After drying, titania-polystyrene coated powder A was obtained. The resulting titania-polystyrene-coated powder A had good dispersibility and was a single particle. Further, the peak wavelength of the spectral reflection curve of this powder A was 448 nm, the reflectance at the peak wavelength was 45%, and it was blue.

Table 1 shows the refractive index and film thickness of the first to third layers.
Shown in

[0031]

[Table 1]

Example 2 (1st layer titania coating) 250 ml of ethanol was added to 10 g of acrylic powder (average particle size 1.5 μm) and dispersed, and the container was heated in an oil bath to a temperature of 5
It was kept at 5 ° C. Titanium isopropoxide 4.5
g was added and stirred. Further, 30 ml of ethanol and water 4.
5 g of the mixed solution was added dropwise over 60 minutes, reacted for 2 hours, diluted and washed with a sufficient amount of ethanol, and then dried at 180 ° C. for 8 hours in a vacuum dryer. After drying, titania-coated powder B ₁ was obtained. Obtained titania-coated powder B ₁
Had good dispersibility and each was a single particle. Further, the peak wavelength of the spectral reflection curve of this powder B ₁ was 545 nm, the reflectance at the peak wavelength was 31%, and it was green.

(Second-layer polystyrene coating) Distilled water (600 g) was charged with styrene monomer (127 g) at 70 ° C.
While heating and stirring, sodium lauryl sulfate was added and emulsified. To this, 25 g of titania-coated powder B ₁ was mixed and stirred at high speed to thoroughly mix. An aqueous solution of ammonium persulfate (10%) was added to this to initiate the polymerization reaction, and the reaction was stirred for 4 hours. After completion of the reaction, the mixture was diluted with 2 liters of distilled water, the upper liquid was discarded by gradient washing, and the precipitate was collected. The precipitate is dried on filter paper and polystyrene-titania coated powder B
Got _two . The obtained polystyrene-titania-coated powder B ₂ had good dispersibility and each was a single particle.

(Third-layer titania coating) 250 ml of ethanol was added to 10 g of polystyrene-titania-coated powder B ₂ and dispersed, and the container was heated in an oil bath to maintain the temperature of the liquid at 55 ° C. 4.5 g of titanium isopropoxide was added to this and stirred. 30 more ethanol
A mixed solution of ml and water (4.5 g) was added dropwise over 60 minutes, reacted for 2 hours, diluted and washed with a sufficient amount of ethanol, and then dried at 180 ° C. for 8 hours in a vacuum dryer. After drying, titania - obtain polystyrene-coated powder B _3. The resulting titania - polystyrene-coated powder B ₃ has good dispersibility and was an independent particle. Also, this powder B ₃
The spectral reflection curve had a peak wavelength of 544 nm, a reflectance of 43% at the peak wavelength, and was green.

(4th layer polystyrene coating) 127 g of styrene monomer was added to 600 g of distilled water and the temperature was changed to 70 ° C.
While heating and stirring, sodium lauryl sulfate was added and emulsified. Titania-polystyrene coated powder B ₃
25 g were mixed and stirred at high speed to mix well. An aqueous solution of ammonium persulfate (10%) was added to this to initiate the polymerization reaction, and the reaction was stirred for 4 hours. After the reaction, distilled water 2
It was diluted with liter, and the supernatant was discarded by decanting and the precipitate was collected. The precipitate was dried on a filter paper, polystyrene - obtain titania-coated powder B _4. The resulting polystyrene - titania-coated powder B ₄ has good dispersibility and was an independent particle.

(Fifth layer titania coating) 250 ml of ethanol was added to 10 g of polystyrene-titania-coated powder B ₄ and dispersed, and the container was heated in an oil bath to maintain the temperature of the liquid at 55 ° C. 4.5 g of titanium isopropoxide was added to this and stirred. 30 more ethanol
A mixed solution of ml and water (4.5 g) was added dropwise over 60 minutes, reacted for 2 hours, diluted and washed with a sufficient amount of ethanol, and then dried at 180 ° C. for 8 hours in a vacuum dryer. After drying, titania-polystyrene coated powder B was obtained. The resulting titania-polystyrene coated powder B had good dispersibility and was a single particle. Further, the peak wavelength of the spectral reflection curve of this powder B was 552 nm, the reflectance at the peak wavelength was 58%, and it was green. Further, the titania film absorbed ultraviolet light of 300 nm or less, and the reflectance was 1% or less in this region.

Table 2 shows the refractive index and film thickness of the first to fifth layers.
Shown in

[0038]

[Table 2]

Example 3 (1st-layer titania coating) 250 ml of ethanol was added to 10 g of acrylic powder (average particle size 1.5 μm) and dispersed, and the container was heated in an oil bath to a temperature of 5
It was kept at 5 ° C. Titanium isopropoxide 5.5
g was added and stirred. Further, 30 ml of ethanol and water 5.
5 g of the mixed solution was added dropwise over 60 minutes, reacted for 2 hours, diluted and washed with a sufficient amount of ethanol, and then dried at 180 ° C. for 8 hours in a vacuum dryer. After drying, titania-coated powder C ₁ was obtained. Obtained titania-coated powder C ₁
Had good dispersibility and each was a single particle.

(Second-layer metallic silver coating) Titania-coated powder C _{1 (} 20 g) was dispersed in a silver solution prepared in advance with stirring. While stirring and dispersing, 600 ml of the reducing solution was added and stirred for 30 minutes. As a result, a metallic silver-titania coat powder C ₂ having good dispersibility was obtained. The silver solution and the reducing solution were prepared as follows. As the silver solution, 8.75 g of silver nitrate was dissolved in 300 ml of distilled water. Since silver oxide was precipitated here, aqueous ammonia (29%) was added until the precipitate was complex ionized. Then, prepare sodium hydroxide prepared in advance in distilled water 30
A solution dissolved in 0 ml was added. Since silver oxide was again precipitated, aqueous ammonia (29%) was added until the precipitate was complex ionized to prepare a silver solution. The reducing solution was prepared by dissolving 45 g of glucose in 1 liter of water, further adding 4 g of tartaric acid to dissolve it, and boiling it for 5 minutes. After cooling, ethanol 100
ml was added to make a reducing solution.

(Third layer titania coating) Metallic silver-
Titania coat powder C ₂ 10g ethanol 250ml
And heat the container in an oil bath to reduce the temperature of the solution to 5.
It was kept at 5 ° C. Titanium isopropoxide 4.5
g was added and stirred. Further, 30 ml of ethanol and water 5.
5 g of the mixed solution was added dropwise over 60 minutes, reacted for 2 hours, diluted and washed with a sufficient amount of ethanol, and then dried at 180 ° C. for 8 hours in a vacuum dryer. After drying, titania
A metallic silver-coated powder C was obtained. The resulting titania-metal silver-coated powder C had good dispersibility and was a single particle. The bottom wavelength of the spectral reflection curve of this powder is 58
It was 5 nm, and the reflectance increased toward both sides. The maximum reflectance was 45%, which was reddish purple. Further, in the infrared region, the reflectance continued to increase at 780 to 910 nm due to reflection by the silver film, and the maximum reflectance was 60%. However, in the ultraviolet region, the silver film and the titania film absorb ultraviolet light of 300 nm or less, and the reflectance is 5% or less in this region.

Table 3 shows the refractive index and film thickness of the first to third layers.
Shown in

[0043]

[Table 3]

[0044]

As described above, according to the light color cosmetic raw material powder of the present invention, it is possible to use a light color cosmetic raw material powder without using a dye or a pigment.
It is possible to design colored powders of single colors such as blue, green and yellow as raw materials for mascara and mayuzu. Since this cosmetic raw material powder does not use dyes or pigments, there is no fading due to the lack or alteration of the dyes or pigments, and clear colors can be maintained for a long period of time. In addition to coloring, for example, U
As a raw material for V-cut (sunscreen) cream, foundation, etc., it is possible to design a powder having a multilayer film structure that absorbs electromagnetic waves of harmful wavelengths such as ultraviolet rays and infrared rays and does not reach the skin.

[Brief description of drawings]

FIG. 1 is a sectional view showing a conceptual structure of a cosmetic raw material powder of the present invention.

FIG. 2 is a graph showing a spectral waveform of the reflection intensity of each unit film constituting a multilayer film of a powder colored white.

FIG. 3 is a graph showing a spectral waveform of the reflection intensity of each unit film constituting a multilayer film of a single-colored powder.

[Explanation of symbols]

 1 powder core particles 2 coating layer 3 coating layer

Claims (5)

[Claims] 1. A cosmetic raw material powder, comprising a plurality of coating layers having different refractive indices on the surface of powder core particles having a specific gravity of 0.3 to 2.8. 2. The cosmetic raw material powder according to claim 1, wherein the powder core particles are an organic substance. 3. The cosmetic raw material powder according to claim 1, wherein at least one of the coating layers is an inorganic metal compound layer. 4. The cosmetic raw material powder according to claim 1, wherein at least one of the coating layers is a metal layer or an alloy layer. 5. The cosmetic raw material powder according to claim 1, wherein at least one of the coating layers is an organic material layer.