JP2000290532A - Manufacture of modified powder, modified powder and cosmetic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly precipitate a solute on surface of powder in a short time without damaging the powder and without producing a recrystallized material by conducting neutralization under a turbulent flow in a process of precipitating the solute on surface of powder in an aqueous solvent using a phenomenon of precipitation of the solute caused by change of pH. SOLUTION: Slurry of powder is mixed with an alkali solution of a solute in an aqueous solvent under turbulent flow and neutralization is preferably conducted by use of an acidic material. The solute to be precipitated is preferably silica, alumina, zirconia, titania, a hydrated compound thereof, a hydroxide thereof or at least one selected from a fluorine-substituted alkyl phosphate, N-acylated lysine and a metallic soap among which N-lauroyl lysine is most preferable. The powder is preferably at least one selected from mica, celicite, titanium, an organic dye and ultramarine blue. The turbulent flow is preferably generated by an aspirator or a line mixer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing p
A method for producing a modified powder, wherein a neutralization treatment in a step of depositing a solute on a powder surface utilizing a precipitation phenomenon of a solute accompanying a change in H is performed under turbulent flow, And a cosmetic containing the modified powder and having excellent sensory characteristics such as a finished feeling. More specifically, as a method for producing a modified powder, in the surface treatment of powder such as an organic dye which is weak in pH change or mica or the like which is difficult to perform homogeneous treatment due to its large shape, turbulent flow The present invention relates to a method for producing a modified powder, wherein a uniform treatment is performed in a short time without deteriorating the powder by performing a neutralization treatment.

[0002]

2. Description of the Related Art The inventor of the present invention disclosed in Japanese Unexamined Patent Publication No. 7-242838 that an oil agent having a specific viscosity was added when N-acylated lysine as a solute was precipitated and recrystallized on the powder surface by neutralization treatment. Then, a method for producing a modified powder was proposed which reduces the amount of recrystallized N-acylated lysine alone.

[0003]

However, even in the above-mentioned method, a single recrystallized form of N-acylated lysine may be slightly generated in some cases, and since an oil having a specific viscosity is used in combination, Depending on the preparation such as cosmetics, the effect of the oil agent may be large.

On the other hand, in the surface treatment of powders utilizing the solute precipitation phenomenon due to the neutralization treatment accompanying the pH change, when handling powders such as organic dyes which are susceptible to a pH change, the change in the pH must be kept as short as possible. It was necessary to do it. That is, the present invention, without altering the powder, in a short time,
Provided is a method of producing a modified powder that uniformly precipitates a solute on a powder surface without generating a recrystallized solute alone, and a cosmetic containing the modified powder and having excellent sensory characteristics. It is intended for.

[0005]

Means for Solving the Problems The present inventor has conducted intensive studies in view of the above-mentioned circumstances, and as a result, by performing a neutralization treatment under strong turbulence, the uniformity of solute deposition on the powder surface has been improved. And succeeded in shortening the time for pH fluctuation. That is, the present invention is characterized in that, in an aqueous solvent, a neutralization treatment in a step of depositing a solute on a powder surface is performed under a turbulent flow, utilizing a solute precipitation phenomenon accompanying a change in pH. In a method for producing a modified powder. The modified powder obtained by the production method is also included. Further, there is a cosmetic containing the modified powder.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The aqueous solvent used in the present invention is
Water or a mixed solvent of water and an organic solvent soluble in water. Examples of water-soluble organic solvents include lower alcohols such as methanol, ethanol, propanol and isopropanol, acetone, N-methylpyrrolidone, dimethyl sulfoxide and the like.

[0007] The solute used in the present invention refers to a substance that is formed as a result of a chemical reaction in a solvent, even if it is dissolved in a solvent, and refers to a substance that is precipitated on the powder surface by a neutralization treatment. For example, silica, alumina, zirconia,
Titania, ceria (cerium oxide), zinc oxide, and hydrates, hydroxides, or fluorine-substituted alkyl phosphates thereof, N-acylated lysine, cationized guar gum, barium sulfate, calcium carbonate, and zinc stearate And the like. Among them,
In particular, one or more compounds selected from the group consisting of silica, alumina, zirconia, titania, and their hydrates, hydroxides, or fluorine-substituted alkyl phosphates, N-acylated lysine, and metal soaps It is preferable for achieving the object of the present invention. The fluorine-substituted alkyl phosphate is, for example, a compound in which part or all of the hydrogen atoms of an alkyl group having 6 to 20 carbon atoms is substituted by fluorine, and a preferred compound is a perfluoroalkyl phosphate, and a salt thereof is Asahi Glass Co., Ltd. AG-500 etc. are mentioned. Further, N-acylated lysine includes N-
Lauroyl-L-lysine and the like can be mentioned, and N-lauroyl-L-lysine is particularly preferable.

[0008] The solute precipitation phenomenon by the neutralization treatment referred to in the present invention is a phenomenon in which a solute is precipitated from a solvent at a pH of about 5 to about 9 or a result of a chemical reaction with a neutralizing solution. , A phenomenon in which a solute is precipitated from a solvent. When this precipitation phenomenon occurs, the powder coexists in the system and is neutralized under turbulent flow, so that a uniform precipitation phenomenon of the solute on the powder surface occurs, and a recrystallized substance consisting of only the solute is generated That is, a uniform surface treatment can be performed.

The powders referred to in the present invention include various powders usually used in cosmetics.
No., Red No. 201, Red No. 202, Yellow No. 4, Black 40
Organic dyes such as No. 1, Yellow No. 4 Al Lake, Yellow No. 203 Ba Lake, polyamide resin powder, silk powder, polyurethane resin powder, polyfluoroethylene resin powder, silicone powder, polymer powder such as cellulose powder, yellow oxidation Iron, red iron oxide, black iron oxide, chromium oxide, carbon black, colored pigments such as ultramarine and navy blue, white pigments such as zinc oxide, titanium oxide and cerium oxide, extender pigments such as talc, mica, sericite, kaolin, Pearl pigments such as titanium mica and iron oxide-coated mica, metal salts such as barium sulfate, calcium carbonate, magnesium carbonate, aluminum silicate and magnesium silicate, inorganic powders such as silica and alumina, fine titanium oxide, fine zinc oxide, and fine oxide Iron, alumina treated fine particle titanium oxide, silica treated fine particle titanium oxide , Bentonite, smectite, and the like. There is no particular limitation on the shape of these powders.

[0010] The production method of the present invention comprises:
It is more suitable for processing powders such as mica, sericite, mica titanium, and organic dyes and ultramarine blue that are vulnerable to pH changes, in which solutes tend to hardly precipitate.

The turbulent flow referred to in the present invention is a phenomenon of a fluid used in comparison with a laminar flow of the fluid. To check whether or not the flow is turbulent, add colored water colored with a dye to the fluid little by little while flowing water through the device, and observe the behavior of the dye water with a video tape recorder (VTR). Thus, the fluid in which the small portions of the fluid were mixed irregularly and the flow including the turbulence was generated was regarded as a turbulent flow. In an industrial tank having a capacity of 50 kg or more, which is an example of a conventional surface treatment apparatus, when agitating vigorously using a stirring device such as a propeller, when a shielding plate is installed on the tank side surface and stirring, centimeters are used. Turbulence is generated in the unit of. However, 0.05 to several tens μ corresponding to the particle size of the powder
When viewed in a local unit such as m, and in a very short time unit related to the neutralization reaction, the ratio of the laminar flow is stronger than the turbulent flow in the conventional stirring device, and the mixing during the neutralization reaction is insufficient. Often have.

On the other hand, as the stirring and mixing apparatus of the production method of the present invention, the neutralization reaction can be carried out using an apparatus such as an aspirator or a line mixer that generates a strong turbulent flow in a local reaction field. preferable. For example, an aspirator is usually used as a decompression device,
There is a feature that the entire system can be instantaneously homogenized by the generation of strong turbulence in a narrow space by the Venturi tube. Also,
Line mixers are simple mixers with a helix in a narrow tube, but high flow rates generate enough turbulence to homogenize the system. Other examples of the turbulence generator include a bead mill and the like, but an aspirator and a line mixer are preferable because they are inexpensive and simple in terms of equipment. However, these devices need to be acid-resistant and alkali-resistant due to the reaction solution, and are coated with polyfluoroethylene resin or ceramics, or the main body of the device is made of polyfluoroethylene resin or ceramics Is preferred. Further, when a line mixer is used as a reaction field, a substance having a large inner diameter of the tube is not preferable because turbulence is weakly generated.
cm.

As an example of the method for producing the modified powder of the present invention, there are the following methods, for example. (1) A powder slurry A of an acidic aqueous solution and an alkaline solution B in which a solute is dissolved are prepared. The powder slurry A is passed through an aspirator using a pump, the alkaline solution B is sucked by the suction force of the aspirator, mixed inside the aspirator, and the mixed solution is collected in another container, filtered, dried and crushed. how to. (2) A slurry A of a solute and a powder dissolved in an alkaline aqueous solution and an acidic solution B for neutralization are prepared. A method in which A and B are simultaneously passed through a line mixer using two pumps, mixed inside the line mixer, and the mixed solution is collected in another container, filtered, dried, and pulverized. (3) The method of (1) and (2) above, wherein the mixed solution is returned to the original slurry tank without being collected in another container, circulated, filtered, dried and pulverized.

In the above methods (1) and (2), p
A system in which H can be easily controlled has an advantage that the entire amount of the powder in the slurry can be surely treated. In addition, the method (3) has an advantage that the equipment is simpler than the methods (1) and (2) because one tank is required. On the other hand, in the conventional method of dropping a reaction solution for neutralization into a tank provided with a stirrer, it is difficult to uniformly treat the entire amount of the powder, or it takes several tens of minutes until the reaction solution is diffused.
There is a drawback that it often takes seconds, during which time the powder is often denatured. Among the above methods, the method (2) is particularly preferable. Further, the solute dissolved in the alkaline aqueous solution and the slurry of the powder are mixed under a turbulent flow, and then mixed under a turbulent flow using an acidic solution for neutralization. Preferably, a sum is performed.
According to this method, a relatively firm coating treatment can be performed even on a powder such as mica, which has a smooth surface and does not easily precipitate a solute. Then, in order to perform a more secure coating process, it is preferable to use a slurry with a high concentration as much as possible when preparing a slurry of the powder.

The amount of the solute to be treated with respect to the powder used in the present invention is preferably 0.5 to 60 parts by weight, more preferably 1 to 20 parts by weight, based on 100 parts by weight of the powder. However, when the amount exceeds 10 parts by weight, the change in pH is large. Therefore, it is preferable that the slurry is not neutralized at once but is gradually neutralized in several parts.

In the reaction system of the powder obtained in this way, depending on the type of the formulation into which the modified powder is blended, as described in JP-A-7-242838, silicone oil or the like may be added. May be added, or the powder may be further coated with a perfluoroalkyl phosphate ester or the like by the method of the present invention. Further, after filtration, drying, and pulverization, conventionally known surface treatment methods other than the method of the present invention, such as fluorine compound treatment, silicone treatment, silicone resin treatment, pendant treatment, silane coupling agent treatment, titanium coupling agent treatment, and oil agent Treatment, N-acylated lysine treatment, polyacrylic acid treatment, metal soap treatment,
The coated surface of the modified powder may be further treated by amino acid treatment, inorganic compound treatment, plasma treatment, mechanochemical treatment or the like.

The amount of the modified powder obtained by the above-mentioned production method of the present invention in a cosmetic is 0.1% with respect to the total amount of the cosmetic.
It is appropriately selected within the range of 100 to 100% by weight.

The cosmetics of the present invention include concealers,
Foundation, white powder, blush, lipstick, eyeshadow,
Makeup cosmetics such as teak, nail color, filter color, etc., hair cosmetics such as rinses, conditioners, hair treatments, milky lotions, lotions, cosmetic creams, cleansing, packs, sunscreens, pore concealment, after-shave lotion, pre-shab lotion And other basic cosmetics, perfumes, soaps, deodorants, body powders and the like.

In the cosmetic of the present invention, in addition to the above-mentioned modified powder, powders (pigments, pigments, resins) usually used in cosmetics, oils, fluorine compounds, resins, surfactants, adhesives,
Preservatives, fragrances, UV absorbers (including organic and inorganic,
UV-A and UV-B may have absorption characteristics), humectants, bioactive components (including ceramides), salts, solvents, antioxidants, chelating agents, neutralizing agents,
Components such as a pH adjuster can be simultaneously added.

In the cosmetic of the present invention, powders that can be blended in addition to the above-mentioned modified powder, which is an essential component, include, for example, Red No. 104, Red No. 201, Red No. 202 as described above.
No. 4, Yellow No. 4, Black No. 401, Yellow No. 4 Al lake, Yellow No. 203 Ba lake and other organic dyes, polyamide resin powder, silk powder, polyurethane resin powder,
Polymer powders such as polyfluoroethylene resin powder, silicone powder, cellulose powder, yellow iron oxide, red iron oxide, black iron oxide, chromium oxide, carbon black,
Ultramarine, navy blue and other colored pigments, zinc oxide, titanium oxide, cerium oxide and other white pigments, talc, mica, sericite,
Extender pigments such as kaolin, titanium mica, pearl pigments such as iron oxide-coated mica, metal salts such as barium sulfate, calcium carbonate, magnesium carbonate, aluminum silicate and magnesium silicate, inorganic powders such as silica and alumina, fine particle titanium oxide, Fine particle zinc oxide, fine particle iron oxide, alumina-treated fine particle titanium oxide, silica-treated fine particle titanium oxide, bentonite, smectite and the like. The size and shape of these powders are not particularly limited.

These powders may be subjected to conventionally known surface treatments other than the treatment method of the present invention, such as fluorine compound treatment, silicone treatment, silicone resin treatment, pendant treatment, silane coupling agent treatment, titanium coupling agent treatment,
Surface treatment may be performed in advance by oil treatment, N-acylated lysine treatment, polyacrylic acid treatment, metal soap treatment, amino acid treatment, inorganic compound treatment, plasma treatment, mechanochemical treatment, or the like.

Examples of oils include higher alcohols such as cetyl alcohol, isostearyl alcohol, lauryl alcohol, hexadecyl alcohol, octyl dodecanol, fatty acids such as isostearic acid, undecylenic acid and oleic acid, glycerin, sorbitol, ethylene glycol, Polyhydric alcohols such as propylene glycol and polyethylene glycol, myristyl myristate, hexyl laurate, decyl oleate, isopropyl myristate, hexyldecyl dimethyloctanoate, glyceryl monostearate, diethyl phthalate, ethylene glycol monostearate, oxystearin Esters such as octyl acid, liquid paraffin, hydrocarbons such as petrolatum, squalane, lanolin, reduced lanolin, waxes such as carnauba wax, Ink oil, cacao butter, coconut oil, palm kernel oil, camellia oil, sesame oil, castor oil, oils such as olive, ethylene-alpha-olefin co-oligomer, and the like.

Examples of other forms of oils include dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenylpolysiloxane, polyether-modified organopolysiloxane, and fluoroalkyl / polyoxyalkylene co-modified organopolysiloxane. , Alkyl-modified organopolysiloxane, terminal-modified organopolysiloxane, fluorine-modified polysiloxane, amodimethicone, amino-modified organopolysiloxane,
Silicone compounds such as sugar-modified silicone, glyceryl-modified silicone, silicone gel, acrylic silicone, trimethylsiloxysilicic acid, and silicone RTV rubber, and fluorine compounds such as perfluoropolyether, pitch fluoride, fluorocarbon, and fluoroalcohol are exemplified.

As the surfactant, for example, an anionic surfactant, a cationic surfactant, a nonionic surfactant, and a betaine surfactant can be used.

Examples of the organic ultraviolet absorber include 2-ethylhexyl paramethoxycinnamate, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4
-Methoxybenzophenone-5-sulfuric acid, 2,2'-dihydroxy-4-methoxybenzophenone, p-methoxyhydrocinnamic acid diethanolamine salt, paraaminobenzoic acid (hereinafter abbreviated as PABA), ethyldihydroxypropyl PABA, glyceryl PABA, salicylic acid Homomenthyl, methyl-O-aminobenzoate, 2-ethylhexyl-2-cyano-3,3-diphenylacrylate, octyldimethyl PABA, octyl salicylate, 2-phenyl-benzimidazole-5-sulfate, triethanolamine salicylate, 3- ( 4-methylbenzylidene) camphor, 2,4-dihydroxybenzophenine, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2- Dorokishi -4-N-octoxybenzophenone, 4-isopropyl dibenzoylmethane, butyl methoxydibenzoylmethane, 4- (3,4
-Dimethoxyphenylmethylene) -2,5-dioxo-
For example, 2-ethylhexyl 1-imidazolidinepropionate can be used. As these ultraviolet absorbers, compounds derivatized with a hydrocarbon polymer, a silicone polymer, silane, or the like based on these skeletons can also be used.

Solvents used in the cosmetic of the present invention include purified water, cyclic silicone, ethanol, light liquid isoparaffin, lower alcohol, ethers, LPG,
Examples include fluorocarbon, N-methylpyrrolidone, fluoroalcohol, perfluoropolyether, volatile linear silicone, and the like.

[0027]

The present invention will be specifically described below with reference to examples and comparative examples. In addition, methods for evaluating various properties of the modified powders and cosmetics of Examples and Comparative Examples are described below.

(1) Confirmation of Precipitation of Single Solute When N-lauroyl-L-lysine is used as a solute, the solute does not precipitate only on the powder surface. Distribution meter (Seishin company P
RO7000S type) about 10 μm in volume average particle size
A peak appears at From the presence or absence of this peak, simple substance precipitation was confirmed. Further, for those having a peak at a site of 10 μm, such as mica and mica titanium,
From the results of the mapping analysis of the scanning electron microscope and the X-ray microanalyzer, the presence or absence of a simple substance was confirmed. In the case where N-lauroyl-L-lysine alone is precipitated and mixed, it is detected by a scanning electron microscope, but not detected by an X-ray microanalyzer.

(2) Confirmation of Surface Treatment State of Powder When the solute has an atomic number equal to or higher than sodium, the powder element and the solute element are determined based on the results of mapping analysis with a scanning electron microscope and an X-ray microanalyzer. The quality of the surface treatment was estimated by confirming the common state.

(3) Sensory Property Test The feel of the cosmetic at the time of application, the finish after application, and the color were examined by 10 professional inspectors. Five points each when the answer is excellent, the finish is beautiful, and the color is beautiful. Each point is 0 when the feel is poor, the finish is poor, and the color is dirty. The total score of all panelists at the time of rating was evaluated according to the criteria in Table 1.

[0031]

[Table 1]

Example 1 A solution A was prepared by dissolving 7 parts of N-lauroyl-L-lysine in a mixed solution of 12.5 parts of 5N sodium hydroxide and 90 parts of purified water. Next, a slurry B was prepared by dispersing 63 parts of Red No. 202 in 1500 parts of purified water. Then
The slurry B is passed through a polyfluoroethylene resin aspirator using a pump, and the solution A is
Was sucked up and mixed under a turbulent flow inside the aspirator to obtain a slurry C. On the other hand, 12 parts of 6N hydrochloric acid was added to 30 parts of purified water.
Solution D diluted in 0 parts was prepared. The slurry C was passed through a polyfluoroethylene resin aspirator using a pump, and the solution D was sucked up using the suction force, a neutralization reaction was performed inside the aspirator, and the solution was collected in a collection container. The amount of the solution D was adjusted by a valve provided between the container containing the solution D and the aspirator, and was set so that the pH of the solution after the neutralization reaction was in the range of 6 to 7. After stirring the collected solution with a propeller for 15 minutes, the solution was filtered using a filter press, washed three times with purified water to remove sodium chloride, and spread in a stainless steel vat.
It was left to stand in a blown air dryer set at ℃ to dry it. The obtained powder was pulverized using an atomizer to obtain a desired modified powder coated with N-lauroyl-L-lysine.

Example 2 A mixed solution of 63 parts of mica titanium, 5 parts of 6N hydrochloric acid and 1000 parts of purified water was stirred with a propeller to prepare a slurry A. On the other hand, a solution B was prepared by dissolving 7 parts of N-lauroyl-L-lysine in a mixed solution of 12.5 parts of 5N sodium hydroxide and 90 parts of purified water. The slurry A and the solution B were respectively sent out into a line mixer (helix in a cylinder having an inner diameter of 3 cm) using a pump to cause a neutralization reaction, and the neutralized solution was collected in a collection container. The amount of solution B was adjusted by a valve installed between the pump and the line mixer, and the pH of the solution after the neutralization reaction was set to be in the range of 6 to 7. After stirring the collected solution with a propeller for 15 minutes, the solution was filtered using a filter press, and purified water was used.
Washing was carried out to remove sodium chloride, spread on a stainless steel vat, and allowed to dry in a blown air dryer set at 80 ° C. The obtained powder was pulverized using an atomizer to obtain a desired modified powder coated with N-lauroyl-L-lysine.

Example 3 A slurry in which 100 parts of sericite was dispersed in 600 parts of purified water using a propeller was obtained, and a solution in which 5 parts of tetrachlorosilane was dissolved in 15 parts of isopropyl alcohol was added dropwise with stirring. A was obtained. On the other hand, a solution B was prepared by dissolving 20 parts of 5N sodium hydroxide in 100 parts of purified water. The slurry A was passed through a polyfluoroethylene resin aspirator using a pump, the solution B was sucked up using the suction force, a neutralization reaction was performed inside the aspirator, and the solution was collected in a collection container. Next, a solution prepared by dissolving 10 parts of a perfluoroalkyl phosphate triethanolamine salt having a perfluoroalkyl group having 8 carbon atoms in purified water was added thereto, and the mixture was allowed to stand for 24 hours to obtain a slurry C. The slurry C was passed through a polyfluorinated ethylene resin aspirator using a pump, and a 0.05N aqueous sulfuric acid solution was sucked up by using the suction force, a neutralization reaction was performed inside the aspirator, and the solution was collected in a collection container. After adjusting the pH of the solution to 7.0, the solution is filtered using a filter press, dried at 110 ° C., pulverized with an atomizer, and coated with the target silica and perfluoroalkyl phosphate ester. I got

Comparative Example 1 A modified powder was obtained in the same manner as in Example 1 except that Solution D was added to slurry B under a propeller and neutralized.

Comparative Example 2 A modified powder was obtained in the same manner as in Example 2 except that Solution B was added to Slurry A under stirring with a propeller and neutralized.

Comparative Example 3 In Example 3, the solution A was neutralized by adding the solution B to the slurry A with stirring with a propeller, and the slurry C was neutralized by adding a 0.05N sulfuric acid aqueous solution with stirring with a propeller. A modified powder was obtained in the same manner as in Example 3.

Example 4 An eye shadow as a cosmetic was prepared according to the following formulation.

[0039]

The above components were mixed with a mixer, passed through a 60 mesh, and pressed on a metal plate using a mold to produce a brown eye shadow.

Comparative Example 4 The modified powder of Comparative Example 1 was used in place of the modified powder of Example 4 (Example 1), and the modified powder of Comparative Example 2 was used instead of the modified powder (Example 2). An eye shadow was produced in the same manner as in Example 4, except that the modified powder of Comparative Example 3 was used instead of the modified powder (Example 3).

The evaluation results of each modified powder are shown in Tables 2 and 3 below.
Shown in

[0043]

[Table 2]

[0044]

[Table 3]

From the results shown in Table 2, in Examples 1 and 2 of the present invention, no simple substance precipitation of N-lauroyl-L-lysine was observed.
It can be seen that the surface treatment is homogeneous. On the other hand, in Comparative Examples 1 and 2, it was found that N-lauroyl-L-lysine was precipitated as a single substance, and the treatment became heterogeneous. Further, when the red No. 202 slurry of Example 1 was compared with the slurry of Comparative Example 1, the powder of Example 1 had higher chroma of the solution, more excellent dispersion stability as slurry, and the powder of the present invention. It was found that the surface treatment method described above has a good effect on the dispersibility and color of the particles. Furthermore, from the results in Table 3, it was found that Example 3 of the present invention had a more uniform surface treatment than Comparative Example 3.

Table 4 shows the evaluation results of the sensory property test for each eye shadow.

[0047]

[Table 4]

From the results shown in Table 4, it was found that Example 4 of the present invention obtained an excellent evaluation result for each evaluation item, whereas Comparative Example 4 showed a slightly lower evaluation. It can be seen that even when the same surface treatment is performed, the sensory characteristic result changes depending on the treatment method, and the evaluation of the sensory characteristic shows that the modified powder which is more homogeneous in Example 4 and has excellent dispersibility is used. Is considered to be the cause of the improvement.

[0049]

As described above, according to the method for producing a modified powder of the present invention, the solute is uniformly deposited only on the powder surface without generating a recrystallized solute alone, Further, it is clear that the cosmetic containing the modified powder obtained by the production method is excellent in various sensory characteristics of touch, finish and color.

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Claims (8)

[Claims] 1. A neutralizing treatment in a step of depositing a solute on a powder surface in a water-based solvent utilizing a solute precipitation phenomenon caused by a change in pH is performed under turbulent flow. Method for producing modified powder. 2. The method according to claim 1, wherein the slurry of the powder and the alkaline solution of the solute are mixed in a turbulent flow in an aqueous solvent, and then neutralization is performed in a turbulent flow using an acidic substance. Production method of modified powder. 3. A solute to be precipitated is silica, alumina,
1 selected from the group consisting of zirconia, titania, and their hydrates, hydroxides, or fluorine-substituted alkyl phosphates, N-acylated lysine, and metal soaps
The method for producing a modified powder according to claim 1, wherein the method is a compound of at least one kind. 4. The method for producing a modified powder according to claim 1, wherein the solute to be precipitated is N-lauroyl lysine. 5. The powder according to claim 1, wherein the powder is at least one compound selected from the group consisting of mica, sericite, mica titanium, an organic dye, and ultramarine blue.
13. The method for producing a modified powder according to the above item. 6. The method according to claim 1, wherein the turbulence is generated by using an aspirator or a line mixer. 7. A modified powder obtained by the production method according to any one of claims 1 to 6. 8. A cosmetic comprising the modified powder according to claim 7.