Water-in-oil emulsified cosmetic or anhydrous cosmetic and method for their production

Abstract

A method for producing a water-in-oil emulsified cosmetic or anhydrous cosmetic, wherein the method includes a step of wet jet mill dispersion treatment of hydrophobically treated inorganic particles at high pressure in an oil as the dispersing medium, the inorganic particles including one or more selected from the group consisting of titanium oxide and iron oxide, and the hydrophobic treatment including one or more different types of treatment with one or more compounds selected from the group consisting of compounds having a straight chain or branched chain with at least 8 carbon atoms in the molecule, amino acids, and salts of the foregoing.

Description

WATER-IN-OIL EMULSIFIED COSMETIC OR ANHYDROUS COSMETIC AND METHOD FOR THEIR PRODUCTION

[0001] The present invention relates to a water-in-oil emulsified cosmetic or anhydrous cosmetic, and to a method for producing them.

[0002] Liquid foundations are a major category of makeup products, and in the Asian market in particular, they are in demand for providing a non-oily, glow skin finish effect, a comfortable skin finish without a powdery feeling, a high coverage effect and a long-lasting effect.

[0003] A water-in-oil emulsified cosmetic suitable for application in liquid foundations is described in JP2021-08413A, as a water-in-oil emulsified cosmetic comprising a non-volatile phenyl-modified silicone, a specific ester oil, titanium oxide microparticles and a hydrophobically treated color pigment, which exhibits a glow skin finish, a lack of stickiness after coating onto skin, and a reduced powdery feeling.

[0004] However, no water-in-oil emulsified cosmetic has yet been reported that is suitable for application in a liquid foundation and exhibits a high coverage effect and long-lasting effect in addition to a non-oily, glow skin finish effect and a comfortable skin finish without a powdery feeling.

[0005] It is an object of the invention to provide a novel water-in-oil emulsified cosmetic or anhydrous cosmetic that exhibits all of the aforementioned effects including a non-oily, glow skin finish effect, a comfortable skin finish without a powdery feeling, a high coverage effect and a long-lasting effect, as well as a method for producing them.

[0006] The invention provides a method for producing a water-in-oil emulsified cosmetic or anhydrous cosmetic, wherein the method includes a step of wet jet mill dispersion treatment of hydrophobically treated inorganic particles at high pressure in an oil as the dispersing medium, the inorganic particles including one or more selected from the group consisting of titanium oxide and iron oxide, and the hydrophobic treatment including one or more different types of treatment with one or more compounds selected from the group consisting of compounds having a straight chain or branched chain with at least 8 carbon atoms in the molecule, amino acids, and salts of the foregoing. By dispersing the hydrophobically treated inorganic particles in an oil by this method using these components, it is possible to vastly improve the dispersed state of the inorganic particles, and to provide a non-oily, glow skin finish effect, a comfortable skin finish without a powdery feeling, a high coverage effect, and a long-lasting effect.

[0007] In the production method of the invention, the compounds having a straight chain or branched chain with at least 8 carbon atoms in the molecule to be used as a hydrophobic treatment agent may be one or more selected from the group consisting of dextrin fatty acid esters, N-acyl amino acids, higher fatty acids, glycolipids, phospholipids, higher alcohols, and salts of the foregoing. By hydrophobically treating the inorganic particles with these components, it is possible to obtain a cosmetic exhibiting a more excellent comfortable skin finish without a powdery feeling, a high coverage effect, and a long-lasting effect.

[0008] In the production method of the invention, a dextrin fatty acid ester used as a hydrophobic treatment agent may be one or more selected from the group consisting of dextrin isostearate, dextrin palmitate and dextrin myristate, an N-acyl amino acid or its salt may be one or more selected from the group consisting of sodium N-lauroylaspartate, sodium N-lauroylglutamate, sodium N-myristoylglutamate and disodium N-stearoylglutamate, a higher fatty acid or its salt may be one or more selected from the group consisting of palmitic acid, stearic acid, isostearic acid, lauric acid and myristic acid, a phospholipid may be hydrogenated lecithin, a higher alcohol may be one or more selected from the group consisting of lauryl alcohol, myristyl alcohol, cetanol, cetearyl alcohol and stearyl alcohol, and an amino acid or its salt may be lysine. By hydrophobically treating the inorganic particles with one or more of these components, it is possible to obtain a cosmetic exhibiting an even more excellent comfortable skin finish without a powdery feeling, a high coverage effect, and a long-lasting effect.

[0009] In the production method of the invention, the pressure (high-pressure) during wet jet mill dispersion treatment of the hydrophobically treated particles in oil is preferably 50 MPa or higher, more preferably 100 MPa or higher and even more preferably 150 MPa or higher. If the pressure during wet jet mill dispersion treatment is within this range it will be possible to obtain an even more excellent non-oily, glow skin finish effect and comfortable skin finish without a powdery feeling.

[0010] In the production method of the invention, the step of wet jet mill dispersion treatment at high pressure may be (1) a step of high-pressure wet jet mill dispersion treatment of the hydrophobically treated inorganic particles and a portion of the oil, and may further include (2) a step of mixing the dispersion obtained in (1) with the remaining oil.

[0011] The oil used in the production method of the invention may include one or more selected from the group consisting of hydrocarbon oils, vegetable oils and ester oils. Hydrocarbon oils may be one or more selected from the group consisting of squalane, vegetable squalane, liquid paraffin, light liquid isoparaffin, C9-12 alkanes, C15-19 alkanes and C18-21 alkanes, vegetable oils may be one or more selected from the group consisting of jojoba oil and olive oil, and ester oils may be one or more selected from the group consisting of coco-caprylate / caprate and caprylic / capric triglyceride.

[0012] The oil used in the production method of the invention may also include one or more surfactants selected from the group consisting of sorbitan fatty acid esters and polyglycerin fatty acid esters. This will allow the storage stability of the cosmetic to be improved.

[0013] The inorganic particles used in the production method of the invention may further include zinc oxide. Including zinc oxide in the inorganic particles can impart a more excellent ultraviolet protection effect to the cosmetic, as well as a longer-lasting effect by improved adsorption into the sebum.

[0014] The invention also provides a water-in-oil emulsified cosmetic or anhydrous cosmetic obtained by a production method that includes a step of wet jet mill dispersion treatment of hydrophobically treated inorganic particles at high pressure in an oil as the dispersing medium, wherein the inorganic particles include one or more selected from the group consisting of titanium oxide and iron oxide, and the hydrophobic treatment includes one or more different types of treatment with one or more compounds selected from the group consisting of compounds having a straight chain or branched chain with at least 8 carbon atoms in the molecule, amino acids, and salts of the foregoing.

[0015] The present invention also provides a cosmetic method for care and / or makeup of skin, wherein the method includes the application onto the skin or lips of a water-in-oil emulsified cosmetic or anhydrous cosmetic obtained by the production method of the invention.

[0016] According to the invention, it is possible to provide a novel water-in-oil emulsified cosmetic or anhydrous cosmetic that exhibits all of the effects including a non-oily, glow skin finish effect, a comfortable skin finish without a powdery feeling, a high coverage effect and a long-lasting effect, as well as a method for producing them. If the water-in-oil emulsified cosmetic or anhydrous cosmetic includes an inorganic ultraviolet scattering agent as inorganic particles, it is possible to provide a cosmetic exhibiting an ultraviolet protection effect in addition to the effects described above, as well as a method for producing it.

[0017] Fig. 1(a) is a photomicrograph at 500x magnification, of a water-in-oil emulsified cosmetic (Comparative Example A-2) obtained by simply mixing hydrophobically treated inorganic particles and an oil without wet jet mill dispersion treatment at high pressure. Fig. 1(b) is a photomicrograph at 500x magnification, of a water-in-oil emulsified cosmetic (Example A-2) obtained by wet jet mill dispersion treatment of hydrophobically treated inorganic particles at high pressure in an oil.

[0018] Preferred embodiments of the invention will now be described, with the understanding that these embodiments are in no way limitative on the invention.

[0019] Method for producing water-in-oil emulsified cosmetic or anhydrous cosmetic The method for producing the cosmetic of the embodiment includes a step of wet jet mill dispersion treatment of hydrophobically treated inorganic particles at high pressure in oil (also referred to hereunder as "high-pressure wet jet mill dispersion treatment step").

[0020] The inorganic particles used in the high-pressure wet jet mill dispersion treatment step may be particles of an inorganic compound (inorganic powder) which are used as an inorganic ultraviolet scattering agent or inorganic pigment in cosmetics. Specific examples of such inorganic particles include titanium oxide, iron oxide, zinc oxide, zirconium oxide and cerium oxide. For an excellent coverage effect, one or more selected from the group consisting of titanium oxide and iron oxide may be used in the high-pressure wet jet mill dispersion treatment step, and preferably both titanium oxide and iron oxide are used. The inorganic particles may also include particles other than titanium oxide and iron oxide, and preferably the inorganic particles further include zinc oxide for a more excellent ultraviolet protection effect and long-lasting effect, for example.

[0021] The mean particle size of the inorganic particles to be used as an inorganic ultraviolet scattering agent is not particularly restricted so long as a scattering and / or reflecting effect is exhibited for ultraviolet rays, but it may be 100 nm to 200 nm, preferably 120 nm to 200 nm, more preferably 140 nm to 190 nm and even more preferably 150 to 185 nm to further increase the ultraviolet scattering effect. The mean particle size of the inorganic particles used as an inorganic pigment is not particularly restricted so long as it can exhibit a function as a pigment, but it is preferably 200 nm to 1000 nm, more preferably 210 nm to 700 nm, and even more preferably 220 nm to 300 nm, for example, to provide a more excellent coverage effect. The mean particle size can be measured using a particle size distribution meter with an X-Ray Disc Centrifuge (XRDC) or Dynamic Light Scattering (DLS) or Laser Diffraction (LD).

[0022] The inorganic particles used in the high-pressure wet jet mill dispersion treatment step are hydrophobically treated by one or more different types of treatment using one or more compounds selected from the group consisting of compounds having a straight chain or branched chain with at least 8 carbon atoms in the molecule, amino acids and salts of the foregoing. A compound having a straight chain or branched chain with at least 8 carbon atoms in the molecule to be used as a hydrophobic treatment agent may be a dextrin fatty acid ester, an N-acyl amino acid or its salt, a higher fatty acid or its salt, a glycolipid, a phospholipid, a higher alcohol or its salt.

[0023] Specific examples of dextrin fatty acid esters to be used as hydrophobic treatment agents include dextrin isostearate, dextrin palmitate and dextrin myristate. Specific examples of N-acyl amino acids or their salts to be used as hydrophobic treatment agents include N-lauroylaspartic acid salts such as sodium N-lauroylaspartate, N-lauroylglutamic acid salts such as sodium N-lauroylglutamate, N-myristoylglutamic acid salts such as sodium N-myristoylglutamate, and N-stearoylglutamic acid salts such as disodium N-stearoylglutamate. Specific examples of higher fatty acids to be used as hydrophobic treatment agents include palmitic acid, stearic acid, isostearic acid, lauric acid and myristic acid. Specific examples of higher alcohols to be used as hydrophobic treatment agents include lauryl alcohol, myristyl alcohol, cetanol, cetearyl alcohol and stearyl alcohol. Lysine is a specific example of an amino acid or salt to be used as a hydrophobic treatment agent.

[0024] The inorganic particles used in the high-pressure wet jet mill dispersion treatment step may have the surfaces partially hydrophobically treated, or they may have the entire surfaces hydrophobically treated. The hydrophobic treatment may be carried out by a common method using these hydrophobic treatment agents.

[0025] When the inorganic particles used in the high-pressure wet jet mill dispersion treatment step include hydrophobized iron oxide, the hydrophobically-treated iron oxide may be of a single type or two or more types, but two or more types are preferred to allow further improvement in the long-lasting effect and comfortable skin finish without a powdery feeling, as well as to provide a more excellent effect of prolonging the initial coated color tone. The phrase "two or more" used here may mean (i) two or more of the same iron oxide (such as (red) iron oxide) hydrophobically treated by different methods, (ii) two or more different types of iron oxides (such as (red) iron oxide and (black) iron oxide) hydrophobically treated by the same method, or (iii) two or more different types of iron oxides (such as (red) iron oxide and (black) iron oxide) hydrophobically treated by different methods.

[0026] Examples of oils (liquid oil agents) as dispersing media to be used in the high-pressure wet jet mill dispersion treatment step include hydrocarbon oils, vegetable oils and ester oils. Specific examples of hydrocarbon oils include squalane, vegetable squalane, liquid paraffin, light liquid isoparaffin, C9-12 alkanes, C15-19 alkanes and C18-21 alkanes. Specific examples of vegetable oils include jojoba oil and olive oil. Specific examples of ester oils include coco-caprylate / caprate and caprylic / capric triglyceride. Preferred among these are squalane, C15-19 alkanes, coco-caprylate / caprate, and mixtures of the same. A single oil agent may be used alone as the dispersing medium, or two or more may be used in combination.

[0027] The oil (liquid oil agent) used as a dispersing medium may also include an organic ultraviolet absorbing agent. As used herein, "organic ultraviolet absorbing agent" means an organic compound that increases the ultraviolet protection effect by absorbing ultraviolet rays. Examples of organic ultraviolet absorbing agents include cinnamic acid-based ultraviolet absorbing agents such as ethylhexyl methoxycinnamate and ethoxyethyl methoxycinnamate; paraaminobenzoic acid-based ultraviolet absorbing agents such as amyl paradimethylaminobenzoate and ethylhexyl paradimethylaminobenzoate; and salicylic acid-based ultraviolet absorbing agents such as ethylhexyl salicylate, benzyl salicylate and homomenthyl salicylate. Salicylic acid-based ultraviolet absorbing agents are preferred among these for a superior ultraviolet protection effect, with ethylhexyl salicylate being more preferred. A single organic ultraviolet absorbing agent may be used alone, or two or more may be used in combination.

[0028] The oil (liquid oil agent) used as a dispersing medium may also include one or more surfactants selected from the group consisting of sorbitan fatty acid esters and polyglycerin fatty acid esters. Specific examples of sorbitan fatty acid esters include sorbitan sesquiisostearate and sorbitan sesquioleate. Specific examples of polyglycerin fatty acid esters include polyglyceryl-6 polyricinoleate and polyglyceryl-2 isostearate. The surfactant used may be a single type alone, or two or more may be used in combination.

[0029] The high-pressure wet jet mill dispersion treatment step may be carried out by using a commercially available wet atomizing apparatus for pressurized spraying of a mixture of hydrophobically treated inorganic particles in an oil as the dispersing medium, with cavitation immediately before spraying, shear force during spraying, or oblique collision between inorganic particles or collision of the inorganic particles with ceramic balls after spraying. The wet atomizing apparatus used for the high-pressure wet jet mill dispersion treatment step may be a "Starburst" (Sugino Machine, Ltd.), "Nanomizer" (Nanomizer Co.), "Nanomaker" (Advanced Nano Technology Co., Ltd.) or "Microfluidizer" (Microfluidics Corporation). The product "Starburst" is preferred among these to obtain higher pressure in the dispersion treatment. The pressure (high-pressure) in this step is preferably 50 MPa or higher, more preferably 100 MPa or higher and even more preferably 150 MPa or higher.

[0030] The high-pressure wet jet mill dispersion treatment step in the method for producing a cosmetic of the embodiment may be a step of carrying out high-pressure wet jet mill dispersion treatment of the hydrophobically treated inorganic particles and all of the oil to obtain a dispersion. This can simplify the overall process for the production of the cosmetic, and shorten the time required for it. The method for producing a cosmetic according to the embodiment may also include (1) a step of high-pressure wet jet mill dispersion treatment of the hydrophobically treated inorganic particles and a portion of the oil, to obtain a dispersion, followed by (2) a step of mixing the obtained dispersion with the remaining oil (this will also be referred to hereunder as "step of mixing with oil"). This can reduce the amount of mixture used in the high-pressure wet jet mill dispersion treatment, thus reducing the amount of energy necessary for the high-pressure wet jet mill dispersion treatment step.

[0031] The oil used in the step of mixing with oil may be the same oil as the dispersing medium used in the high-pressure wet jet mill dispersion treatment step. The oil may further include one or more types of surfactant selected from the group consisting of the aforementioned organic ultraviolet absorbing agents, sorbitan fatty acid esters and polyglycerin fatty acid esters.

[0032] The step of mixing with oil may be carried out, for example, by mixing the dispersion obtained in the high-pressure wet jet mill dispersion treatment step with the oil using a commercially available homogenizer.

[0033] For production of a water-in-oil emulsified cosmetic of the embodiment, the method for producing a cosmetic according to the embodiment may further include a step of mixing the aqueous medium with the dispersion obtained by the high-pressure wet jet mill dispersion treatment step or the mixture obtained in the step of mixing with oil (this step may also be referred to hereunder as "step of mixing with an aqueous medium").

[0034] The aqueous medium may consist of water alone, or it may also include a solvent that is soluble in water.

[0035] Examples of solvents that are soluble in water include monools such as ethanol, propyl alcohol, isopropyl alcohol and phenoxyethanol; and polyhydric alcohols such as ethylene glycol, propanediol (1,2-propanediol, 1,3-propanediol), propylene glycol, butylene glycol, pentylene glycol(1,2-pentanediol), hexylene glycol, 1,2-hexanediol, dipropylene glycol, polyethylene glycol, glycerin, diglycerin, polyglycerin, sorbitol, xylitol, mannitol and caprylyl glycol. The solvent that is soluble in water may be a single one used alone, or two or more may be used in combination. Preferred among the above are glycerin, butylene glycol, pentylene glycol and propanediol.

[0036] The aqueous medium may also further include an organic ultraviolet absorbing agent that is soluble in water. Examples of organic ultraviolet absorbing agents that are soluble in water include phenylbenzimidazolesulfonic acid and hydroxymethoxybenzophenonesulfonic acid, which may be added to the aqueous medium by neutralization with a base. The organic ultraviolet absorbing agent that is soluble in water may be a single one used alone, or a combination of two or more thereof may be used. Phenylbenzimidazolesulfonic acid is preferred among these.

[0037] The step of mixing with an aqueous medium may be carried out, for example, by mixing the dispersion obtained in the high-pressure wet jet mill dispersion treatment step or the mixture obtained by the step of mixing with oil, with the aqueous medium, using a commercially available homogenizer.

[0038] The anhydrous cosmetic may contain no water or may contain water in an amount of 3 mass% or less based on the total mass of the cosmetic.

[0039] Water-in-oil emulsified cosmetic or anhydrous cosmetic The water-in-oil emulsified cosmetic or anhydrous cosmetic of the embodiment is obtained by a production method that includes a step of wet jet mill dispersion treatment of hydrophobically treated inorganic particles at high pressure in an oil as the dispersing medium, wherein the inorganic particles include one or more selected from the group consisting of titanium oxide and iron oxide, and the hydrophobic treatment includes one or more different types of treatment with one or more compounds selected from the group consisting of compounds having a straight chain or branched chain with at least 8 carbon atoms in the molecule, amino acids, and salts of the foregoing. Therefore, the water-in-oil emulsified cosmetic or anhydrous cosmetic of the embodiment comprises at least hydrophobically treated inorganic particles and an oil. The hydrophobically treated inorganic particles and oil in the water-in-oil emulsified cosmetic or anhydrous cosmetic are as explained above under "Method for producing water-in-oil emulsified cosmetic or anhydrous cosmetic".

[0040] When the cosmetic of the embodiment is a water-in-oil emulsified cosmetic, the content of the hydrophobically treated inorganic particles in the cosmetic may be 3 to 30 mass%, and is preferably 5 to 25 mass% and more preferably 7 to 17 mass%, based on the total mass of the cosmetic.

[0041] When the cosmetic of the embodiment is a water-in-oil emulsified cosmetic, the content of the oil in the cosmetic may be 5 to 45 mass%, and is preferably 10 to 35 mass% and more preferably 15 to 25 mass%, based on the total mass of the cosmetic.

[0042] When the cosmetic of the embodiment is an anhydrous cosmetic, the content of the hydrophobically treated inorganic particles in the cosmetic may be 10 to 40 mass%, and is preferably 15 to 35 mass% and more preferably 20 to 30 mass%, based on the total mass of the cosmetic.

[0043] When the cosmetic of the embodiment is an anhydrous cosmetic, the content of the oil in the cosmetic may be 35 to 85 mass%, and is preferably 45 to 75 mass% and more preferably 55 to 65 mass%, based on the total mass of the cosmetic.

[0044] When the cosmetic of the embodiment is a water-in-oil emulsified cosmetic, the cosmetic may further comprise an aqueous medium. The aqueous medium in the cosmetic is as explained above under "Method for producing water-in-oil emulsified cosmetic or anhydrous cosmetic". The content of the aqueous medium in the cosmetic may be 20 to 90 mass%, preferably 35 to 80 mass% and more preferably 50 to 70 mass% based on the total mass of the cosmetic.

[0045] The cosmetic of the embodiment may also comprise one or more surfactants selected from the group consisting of sorbitan fatty acid esters and polyglycerin fatty acid esters. The content of the surfactant in the cosmetic may be 0.1 to 10 mass%, preferably 0.5 to 8 mass% and more preferably 1 to 6 mass% based on the total mass of the cosmetic.

[0046] The cosmetic of the embodiment may also contain, in addition to these components, inorganic salts, pH regulators, chelating agents, antioxidants, antifading agents, antiseptic agents, active ingredients, stabilizers and perfumes, added as appropriate in order to impart various effects.

[0047] Since the cosmetic of the embodiment has all of the aforementioned effects including a non-oily, glow skin finish effect, a comfortable skin finish without a powdery feeling, a high coverage effect and a long-lasting effect, it can be suitably used as a skin cosmetic, and is preferably used by application onto the skin (excluding the scalp), and more preferably onto the face, body and limbs. The cosmetic can be used as a liquid foundation, concealer or cosmetic base, for example, and is preferably used as a liquid foundation.

[0048] The present invention will now be explained in specific detail through the following Examples, with the understanding that the invention is not limited by the Examples.

[0049] (Production Example 1 for water-in-oil emulsified cosmetics) Water-in-oil emulsified cosmetics were prepared with the compositions listed in Tables 1 and 2, by the following steps. Step 1 (Examples A-1 to A-5 and B-1, and Comparative Example A-3): The inorganic particles (A) were added to a portion of the oil (B1), and a high pressure wet jet mill (Star Burst Mini: Sugino Machine, Ltd.) was used for high-pressure dispersion. The pressure during dispersion was 200 MPa for Examples A-1 to A-4, Comparative Example A-3 and Example B-1, and 100 MPa for Example A-5. Step 1' (Comparative Examples A-1, A-2 and B-1): The inorganic particles (A) were added to a portion of the oil (B1), and three roll mills were used for dispersion. Step 2: The mixture obtained in step 1 or the mixture obtained in step 1' were added to the remainder of the oil (B2) and the oily components, and a homogenizer was used for mixing at room temperature. Step 3: The aqueous medium (C) and the aqueous components were mixed at room temperature using a homogenizer. Step 4: The mixture obtained in step 3 was added to the mixture obtained in step 2, and a homogenizer was used for emulsification at room temperature. Step 5: When necessary, the filler (D) was added to the mixture obtained in step 4, and a homogenizer was used for dispersion at room temperature.

[0050] (Production Example 2 for water-in-oil emulsified cosmetics) Water-in-oil emulsified cosmetics were prepared with the compositions listed in Table 3, by the following steps. Step 1 (Example C-1): The inorganic particles (A) were added to the oil (B) and the oily components, and a high pressure wet jet mill (Star Burst Mini: Sugino Machine, Ltd.) was used for high-pressure dispersion. The pressure during dispersion was 200 MPa. Step 1' (Comparative Example C-1): The inorganic particles (A) were added to the oil (B), and a bead mill was used for dispersion. Step 2: The aqueous medium (C) and the aqueous components were mixed at room temperature using a homogenizer. Step 3: The mixture obtained in step 2 was added to the mixture obtained in step 1 or the mixture obtained in step 1', and a homogenizer was used for emulsification at room temperature. Step 4: When necessary, the filler (D) was added to the mixture obtained in step 3, and a homogenizer was used for dispersion at room temperature.

[0051] (Production Example for anhydrous cosmetics) Anhydrous cosmetics were prepared with the compositions listed in Table 4, by the following steps. Step 1 (Example D-1): The inorganic particles (A) were added to a portion of the oil (B1), and a high pressure wet jet mill (Star Burst Mini: Sugino Machine, Ltd.) was used for high-pressure dispersion. The pressure during dispersion was 200 MPa. Step 1' (Comparative Example D-1): The inorganic particles (A) were added to a portion of the oil (B1), and three roll mills were used for dispersion. Step 2: The mixture obtained in step 1 or the mixture obtained in step 1' were added to the remainder of the oil (B2) and the oily components, and a homogenizer was used for mixing at room temperature. Step 3: When necessary, the filler (D) was added to the mixture obtained in step 2, and a homogenizer was used for dispersion at room temperature.

[0052] (Organoleptic evaluation) The cosmetics of the Examples and Comparative Examples were applied onto the facial skin of 10 cosmetic experts of an evaluation panel (ages 25 to 55), and the glow cosmetic finish, the high coverage effect, the comfortable skin finish without powdery feeling and the long-lasting effect were evaluated on the following scale. For the long-lasting property, the condition 8 hours after application was evaluated on the scale shown below. The term "blemish" refers to a portion of the skin that appears darker than the surrounding area due to deposition of pigments such as melanin present on the surface or inside the skin. For this test it is assumed that the cosmetic is applied onto the skin in the morning and the condition is evaluated in the evening. Cosmetics receiving an evaluation of A to C were judged to have acceptable properties. The evaluation results are shown in Tables 1 to 4.

[0053] Evaluation scale for glow cosmetic finish A: Very excellent (e.g.: 9 to 10 evaluators out of 10, perceived a glow cosmetic finish) B: Excellent (e.g.: 7 to 8 evaluators out of 10, perceived a glow cosmetic finish) C: Good (e.g.: 5 to 6 evaluators out of 10, perceived a glow cosmetic finish) D: Fair (e.g.: 3 to 4 evaluators out of 10, perceived a glow cosmetic finish) E: Poor (e.g.: 1 to 2 evaluators out of 10, perceived a glow cosmetic finish) F: Very poor (e.g.: None of the evaluators perceived a glow cosmetic finish)

[0054] Evaluation scale forhigh coverage effect A: Very excellent (e.g.: blemishes and pores completely concealed.) B: Excellent (e.g.: blemishes not visible, but pores visible to 1 or 2 individuals out of 10) C: Good (e.g.: blemishes not visible, but pores visible to 3 to 5 individuals out of 10) D: Fair (e.g.: blemishes and pores visible to 1 or 2 individuals out of 10) E: Poor (e.g.: blemishes and pores visible to 3 to 5 individuals out of 10) F: Very poor (e.g.: blemishes and pores visible to 6 to 10 individuals out of 10)

[0055] Evaluation scale for comfortable skin finish without powdery feeling A: Very excellent (e.g.: Homogeneous cosmetic film formed, absolutely no visible powder aggregation.) B: Excellent (e.g.: Some non-homogeneous locations formed in cosmetic film, but absolutely no visible powder aggregation.) C: Good (e.g.: 1 or 2 individuals out of 10, noted visible powder aggregation at locations on the face.) D: Fair (e.g.: 3 to 5 individuals out of 10, noted visible powder aggregation at locations on the face.) E: Poor (e.g.: 6 to 10 individuals out of 10, noted visible powder aggregation at locations on the face.) F: Very poor (e.g.: 6 to 10 individuals out of 10, noted visible powder aggregation over entire face.)

[0056] Evaluation scale for long-lasting property A: Very excellent (e.g.: no breakup of the cosmetic even after 8 hours) B: Excellent (e.g.: no breakup of the cosmetic after 4 hours, but breakup of the cosmetic experienced by 1 or 2 individuals out of 10, after 8 hours) C: Good (e.g.: no breakup of the cosmetic after 4 hours, but breakup of the cosmetic experienced by 3 to 5 individuals out of 10, after 8 hours) D: Fair (e.g.: breakup of the cosmetic experienced by 1 or 2 individuals out of 10, after 4 hours) E: Poor (e.g.: breakup of the cosmetic experienced by 3 to 5 individuals out of 10, after 4 hours) F: Very poor (e.g.: breakup of the cosmetic experienced by 6 to 10 individuals out of 10, after 4 hours)

[0057] (Stability evaluation) The cosmetics of the Examples and Comparative Examples were each filled into a transparent container and sealed with a cap, and then stored for 1 month at 50°C. As a control, each cosmetic was also used after storage for 1 month at room temperature. The outer appearance of each stored cosmetic was visually observed and evaluated as "F" when powder aggregation was observed, or as "A" if powder aggregation was not observed. Here, "powder aggregation" refers to non-uniform dispersion of the pigment leading to uneven color, as compared to the control. The evaluation results are shown in Tables 1 to 4.

[0058] (Evaluation of outer appearance) The water-in-oil emulsified cosmetics of Example A-2 and Comparative Example A-2 were photographed at 500x magnification using a microscope. A magnified image of Comparative Example A-2 is shown in Fig. 1(a), and a magnified image of Example A-2 is shown in Fig. 1(b). As clearly seen in Fig. 1, with the water-in-oil emulsified cosmetic of Comparative Example A-2 which was obtained by simple mixing of the hydrophobically treated inorganic particles and oil without wet jet mill dispersion treatment at high pressure, the dispersion was insufficient and aggregation of the particles was confirmed, whereas with the water-in-oil emulsified cosmetic of Example A-2 which was obtained with wet jet mill dispersion treatment of the hydrophobically treated inorganic particles in oil at high pressure, the particles were uniformly dispersed, without visible aggregation.

[0059] (Evaluation of ultraviolet protection effect) The ultraviolet protection effects of the water-in-oil emulsified cosmetics of Example B-1 and Comparative Example B-1 were evaluated by an in vivo SPF measurement test. The in vivo SPF measurement test was carried out with reference to ISO24444, and the average measurement value by 3 participants was recorded as the SPF value. The results are shown in Table 2. Example B-1 which was obtained with wet jet mill dispersion treatment of the hydrophobically treated inorganic particles in oil at high pressure exhibited a higher SPF value than Comparative Example B-1 which was obtained by simple mixing of the hydrophobically treated inorganic particles and oil without wet jet mill dispersion treatment at high pressure, despite both having the same composition.

[0060]

[0061]

[0062]

[0063]

Claims

1. A method for producing a water-in-oil emulsified cosmetic or anhydrous cosmetic, wherein the method includes a step of wet jet mill dispersion treatment of hydrophobically treated inorganic particles at high pressure in an oil as the dispersing medium, the inorganic particles including one or more selected from the group consisting of titanium oxide and iron oxide, and the hydrophobic treatment including one or more different types of treatment with one or more compounds selected from the group consisting of compounds having a straight chain or branched chain with at least 8 carbon atoms in the molecule, amino acids, and salts of the foregoing.

2. The method according to claim 1, wherein the compound having a straight chain or branched chain with at least 8 carbon atoms in the molecule is one or more selected from the group consisting of dextrin fatty acid esters, N-acyl amino acids, higher fatty acids, glycolipids, phospholipids, higher alcohols, and salts of the foregoing.

3. The method according to claim 2, wherein the dextrin fatty acid ester is one or more selected from the group consisting of dextrin isostearate, dextrin palmitate and dextrin myristate, the N-acyl amino acid or its salt is one or more selected from the group consisting of sodium N-lauroylaspartate, sodium N-lauroylglutamate, sodium N-myristoylglutamate and disodium N-stearoylglutamate, the higher fatty acid is one or more selected from the group consisting of palmitic acid, stearic acid, isostearic acid, lauric acid and myristic acid, the phospholipid is hydrogenated lecithin, the higher alcohol is one or more selected from the group consisting of lauryl alcohol, myristyl alcohol, cetanol, cetearyl alcohol and stearyl alcohol, and the amino acid is lysine.

4. The method according to any one of claims 1 to 3, wherein the high pressure is 50 MPa or greater, preferably 100 MPa or greater and more preferably 150 MPa or greater.

5. The method according to any one of claims 1 to 4, wherein the step of wet jet mill dispersion treatment at high pressure is (1) a step of high-pressure wet jet mill dispersion treatment of the hydrophobically treated inorganic particles and a portion of the oil, and further includes (2) a step of mixing the dispersion obtained in (1) with the remaining oil.

6. The method according to any one of claims 1 to 5, wherein the oil includes one or more selected from the group consisting of hydrocarbon oils, vegetable oils and ester oils.

7. The method according to claim 6, wherein the hydrocarbon oil is one or more selected from the group consisting of squalane, vegetable squalane, liquid paraffin, light liquid isoparaffin, C9-12 alkanes, C15-19 alkanes and C18-21 alkanes, the vegetable oil is one or more selected from the group consisting of jojoba oil and olive oil, and the ester oil is one or more selected from the group consisting of coco-caprylate / caprate and caprylic / capric triglyceride.

8. The method according to any one of claims 1 to 7, wherein the oil further includes one or more surfactants selected from the group consisting of sorbitan fatty acid esters and polyglycerin fatty acid esters.

9. The method according to any one of claims 1 to 8, wherein the inorganic particles further include zinc oxide.

10. A water-in-oil emulsified cosmetic or anhydrous cosmetic obtained by a production method that includes a step of wet jet mill dispersion treatment of hydrophobically treated inorganic particles at high pressure in an oil as the dispersing medium, wherein the inorganic particles include one or more selected from the group consisting of titanium oxide and iron oxide, and the hydrophobic treatment includes one or more different types of treatment with one or more compounds selected from the group consisting of compounds having a straight chain or branched chain with at least 8 carbon atoms in the molecule, amino acids, and salts of the foregoing.

11. A cosmetic method for care and / or makeup of skin, wherein the method includes the application to skin of a water-in-oil emulsified cosmetic or anhydrous cosmetic obtained by the method according to any one of claims 1 to 9.

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