Metal soap particles, method for producing metal soap particles, and cosmetic

Abstract

The present invention provides: metal soap particles which enable both the achievement of a dry feeling and a moist feeling against skin and the improvement in a soft-focus effect of making wrinkles or the like inconspicuous; a method for producing metal soap particles; and a cosmetic. Metal soap particles according to the present invention each contain a fatty acid salt and contain no metal oxide, and have a volume medial diameter (D50) of 0.5-200 μm and an average circularity of 0.93-1.00, wherein the metal constituting the fatty acid salt comprises one or more metals selected from Mg, Ca, Zn, Ti, Al, Ba, Pb, Mo, Mn, and Fe.

Description

Metal soap particles, method for producing metal soap particles, and cosmetics

[0001] The present invention relates to metal soap particles, a method for producing metal soap particles, and a cosmetic.

[0002] Patent Document 1 discloses a metal soap and a method for producing the same that can impart high dispersibility or coating properties to a powder and improve the powder's anti-caking properties, flowability, and tactile feel. This metal soap is characterized by an internal incorporation rate A, defined as the proportion of an inorganic crystal nucleating agent incorporated into the interior of the metal soap particle, of 30% or more.

[0003] Patent No. 6729546

[0004] Patent Document 1 suggests that the inorganic crystal nucleating agent incorporated into the interior of the metal soap particles acts to make the particle shape uniform and the particle size distribution sharp, and as a result, the solid powder cosmetic in the examples has a good feel to the touch. However, the invention described in Patent Document 1 has limitations on the properties that can be obtained because the inorganic crystal nucleating agent (inorganic oxide) is embedded inside the particles.

[0005] The present invention provides metal soap particles that (1) provide a smooth and moist feel to the skin and (2) can improve the soft focus effect of making wrinkles less noticeable, a method for producing the metal soap particles, and cosmetics.

[0006] The present invention includes the following aspects. [1] Metal soap particles containing a fatty acid salt but no metal oxide, wherein the metal soap particles have a volume-based median diameter (D50) of 0.5 to 200 μm, an average circularity of 0.93 to 1.00, and the metal constituting the fatty acid salt is one or more selected from Mg, Ca, Zn, Ti, Al, Ba, Pb, Mo, Mn, and Fe. [2] Metal soap particles according to [1], wherein the fatty acid constituting the fatty acid salt is a saturated fatty acid. [3] Metal soap particles according to [1] or [2], wherein the fatty acid constituting the fatty acid salt is a saturated fatty acid having from 12 to 22 carbon atoms. [4] Metal soap particles according to any one of [1] to [3], wherein the ratio (D10 / D50) of the 10% diameter (D10) of the metal soap particles to the volume-based median diameter (D50) of the metal soap particles is 0.15 or more. [5] Metal soap particles according to any one of [1] to [4], characterized in that the proportion of metal soap particles having a circularity of 0.70 or less is 20% or less on a number basis among the metal soap particles. [6] A method for producing metal soap particles according to any one of [1] to [5], characterized in that it comprises a grinding step of grinding a solid material of a fatty acid salt, and a spheronizing step of spheronizing the particles obtained in the grinding step. [7] A method for producing metal soap particles according to [6], characterized in that the spheronizing step spheroidizes the particles by heating. [8] A cosmetic comprising the metal soap particles according to any one of [1] to [5].

[0007] According to the present invention, it is possible to provide metal soap particles, a method for producing metal soap particles, and cosmetics that (1) provide a smooth and moist feel to the skin and (2) can improve the soft focus effect that makes wrinkles and the like less noticeable.

[0008] The present invention will be described below using embodiments, but these embodiments are specifically described to provide a better understanding of the gist of the invention and do not limit the present invention unless otherwise specified. Other embodiments in which those skilled in the art appropriately replace the configurations of the following embodiments are also included in the scope of the present invention.

[0009] The metal soap particles of this embodiment are metal soap particles that contain a fatty acid salt but no metal oxide, and have a volume-based median diameter (D50) of 0.5 to 200 μm and an average circularity of 0.93 to 1.00. The metal soap particles may contain a free fatty acid as an added component in addition to the fatty acid corresponding to the fatty acid ion in the fatty acid salt, or may not contain such a free fatty acid. Furthermore, the metal soap particles may contain a metal as a substance or compound other than a metal oxide as an added component to the metal soap particles in addition to the metal in the fatty acid salt, or may not contain such a metal.

[0010] <Fatty Acid Salt> The metal soap particles contain a fatty acid salt. Examples of metals constituting the fatty acid salt include one or more of Mg, Ca, Zn, Ti, Al, Ba, Pb, Mo, Mn, and Fe. These metals are divalent or higher metals that can form a metallic bond with the fatty acid as the metal soap.

[0011] Fatty acids constituting the fatty acid salt include saturated fatty acids and unsaturated fatty acids. Saturated fatty acids constituting the fatty acid salt are not particularly limited, but include hexanoic acid, caproic acid (n-hexanoic acid), heptanoic acid, octanoic acid, caprylic acid (n-octanoic acid), nonanoic acid, decanoic acid, capric acid (n-decanoic acid), lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid, behenic acid, montanic acid, and the like. Among these, saturated fatty acids having 12 to 22 carbon atoms are preferred. Unsaturated fatty acids are not particularly limited, but include oleic acid, linoleic acid, linolenic acid, and the like.

[0012] The carbon number of the fatty acid constituting the fatty acid salt is preferably 12 to 22, more preferably 12 to 20, and particularly preferably 12 to 18. When the carbon number is equal to or greater than the lower limit, the metal soap particles can have an improved pleasant feel, such as a smooth feel and a moist feel. When the carbon number is equal to or less than the upper limit, the metal soap particles can be easily obtained industrially.

[0013] Since saturated higher fatty acids do not have double bonds (unsaturated bonds) in the hydrocarbon chain, they are highly chemically stable, resistant to deterioration by oxygen and ultraviolet light, and tend to maintain excellent quality. The saturated higher fatty acid salts may be branched, but saturated higher fatty acid salts having two or fewer carbon atoms in the branched side chain are preferred, and saturated higher fatty acid salts having one or fewer carbon atoms are more preferred. Linear saturated higher fatty acid salts are particularly preferred.

[0014] When the fatty acid salt is a linear saturated higher fatty acid salt, the hydrocarbon chain has no double bonds (unsaturated bonds) or side chains, resulting in a stable structure. In addition, the methyl groups at the molecular ends are neatly arranged on the surface of the metallic soap particles, and the high melting point makes it difficult for the salt to become liquid at room temperature (5 to 35°C), making it easy to maintain excellent quality.

[0015] The fatty acid salt has a carboxylate ion group (—COO － In addition to the above, it is preferable that the fatty acid salt does not contain polar functional groups such as hydroxyl groups and epoxy groups. This improves hydrophobicity. The general formula of the fatty acid salt is (RCOO) ｍ When represented by M, at least a part or all of the aliphatic groups R are C ｎ－１ H ２ｎ－１ - is preferably a non-cyclic alkyl group represented by CH ３ (CH ２ ) ｎ－２ In these general formulae, n represents the number of carbon atoms, and M represents a metal.

[0016] When the metal M of the fatty acid salt is polyvalent, that is, when m is 2 or greater, the carbon number n of the m fatty acids constituting the fatty acid salt may be the same or different. When the carbon numbers n of the m fatty acids are different from one another, the difference between the maximum carbon number and the minimum carbon number is preferably 4 or less, more preferably 2 or less, and it is even more preferable that the carbon numbers of the fatty acids constituting the fatty acid salt are the same.

[0017] <Metal soap particles> The volume-based median diameter (D50) of the metal soap particles is 0.5 to 200 μm. The D50 is more preferably 1 to 50 μm, and particularly preferably 2 to 15 μm. When the D50 of the metal soap particles is equal to or greater than the lower limit, a smooth feeling can be ensured. When the D50 of the metal soap particles is equal to or less than the upper limit, a moist feeling can be ensured.

[0018] The average circularity of the metal soap particles is 0.93 to 1.00. The average circularity is more preferably 0.94 to 1.00, and particularly preferably 0.95 to 1.00. When the average circularity of the metal soap particles is equal to or greater than the lower limit, a smooth feeling can be ensured and light diffusibility can also be ensured. The upper limit of the average circularity is 1.00 when the particle shape is spherical.

[0019] The circularity can be calculated by analyzing a particle image, measuring the area A and the perimeter C of the particle image, and using the following formula, where D is the diameter of a circle (equivalent circle diameter) equal to the area A of the particle image and π is the ratio of the circumference of a particle to its circumference: (Circularity) = πD / C

[0020] As a method for measuring the circularity of particles, for example, a flow particle image analyzer that measures particle shape, particle size distribution, particle number, etc. by two-dimensional image analysis of a particle group may be used. Alternatively, the circularity may be calculated by observing the particle surface from multiple fields of view using an electron microscope and performing three-dimensional image analysis.

[0021] The ratio (D10 / D50) of the 10% diameter (D10) to the volume-based median diameter (D50) of the metal soap particles is preferably 0.15 or more. D10 / D50 is more preferably 0.20 or more, and particularly preferably 0.25 or more. By having D10 / D50 equal to or greater than the lower limit, the smooth feeling can be improved.

[0022] The 10% diameter (D10) means the diameter at which 10% of particles have a particle diameter smaller than D10 when measuring the volume-based particle size distribution. Similarly, the diameter at which 50% of particles have a particle diameter smaller than D50 (50% diameter) is synonymous with the volume-based median diameter.

[0023] The proportion of metal soap particles having a circularity of 0.70 or less in the metal soap particles is preferably 20% or less, more preferably 15 or less, and particularly preferably 10 or less, on a number basis. When the proportion is equal to or greater than the lower limit, the smooth feeling can be improved.

[0024] The proportion of the fatty acid salt in the metallic soap particles is, for example, 90% by weight or more, or 95% by weight or more. Metal oxides that are not contained in the metallic soap particles include, but are not limited to, oxides of typical metals, oxides of transition metals, and oxides of semimetals. ２ O, Na ２ O, Al ２ O ３ , MgO, CaO, ZnO, BaO, TiO ２ , SiO ２ , Fe ３ O ４ , Fe ２ O ３ , FeO, mica, talc, kaolin, sericite, zirconia, zeolite, etc. The metal soap particles do not contain metal oxides and may contain other components within the range that does not impair the functionality of the metal soap particles.

[0025] The metal soap particles can contain fatty acids. Here, the fatty acids contained in the metal soap particles are free fatty acids that do not constitute the fatty acid salt. When the metal soap particles contain such fatty acids, they may contain the same fatty acids as those that constitute the fatty acid salt, or they may contain fatty acids that are different from those that constitute the fatty acid salt.

[0026] The metal soap particles can contain a metal. Here, the metal contained in the metal soap particles is a metal that does not constitute a fatty acid salt, a metal oxide, or the like, and is an added component to the metal soap particles. When the metal soap particles contain such a metal, the metal may contain the same metal as the metal that constitutes the fatty acid salt, or may contain a metal that is different from the metal that constitutes the fatty acid salt. Examples of such metals that may be contained in the metal soap particles include one or more selected from Li, Na, K, Mg, Ca, Ti, Zn, Ba, Al, Pb, Mo, Mn, and Fe.

[0027] Metal soap particles can be used as various functional materials, and although their uses are not particularly limited, examples of their uses include texture improvers, lubricants, release agents, anti-caking agents, cosmetic raw materials, colorants, processing aids, dispersants, and additives.

[0028] <Method for producing metal soap particles> The metal soap particles of this embodiment can be produced by a method including a grinding step of grinding a solid fatty acid salt, and a spheronization step of spheronizing the particles obtained in the grinding step.

[0029] When the metal soap particles contain other components (fatty acids, metals, etc.), it is preferable to have a kneading step of melting and kneading a mixed powder of the fatty acid salt and the other components before the pulverization step. Even when the kneading step is not performed, it is preferable to carry out a melting step of heating and melting the fatty acid salt before the pulverization step.

[0030] The kneading step is preferably carried out under conditions in which the fatty acid salt is melted or softened by heating. The kneading machine used may be a batch kneader or a continuous kneader. Examples of the kneading machine include, but are not limited to, an open roll, a kneader, a pressure kneader, a Banbury mixer, a single-screw extruder, and a twin-screw extruder. The heating temperature in the kneading step can be appropriately set depending on the melting point of the fatty acid salt, and may be, for example, about 80 to 250°C, about 100 to 200°C, or 100 to 140°C.

[0031] When a kneading step of the fatty acid salt with other components (fatty acids, metals, etc.) or a melting step of the fatty acid salt is carried out prior to the pulverization step, it is preferable to carry out a cooling step in which the kneaded product obtained in the kneading step or the molten product obtained in the melting step is cooled. Residual heat may be absorbed by a cooling member in contact with the kneaded product or the molten product, for example, by passing the molten kneaded product or the molten product through a cooling roll. The cooling member, such as a cooling roll, may have a refrigerant, such as cooling water, inside. In the cooling step, heat can also be dissipated from the kneaded product by air cooling, blowing air, etc.

[0032] The pulverization step may be carried out in multiple stages, such as a coarse pulverization step and a fine pulverization step. The device used for coarse pulverization of particles is not particularly limited, but a crusher, hammer mill, feather mill, cutter mill, etc. can be used. The device used for fine pulverization of particles is not particularly limited, but a jet mill, counter jet mill, high-speed rotor rotary mill, etc. can be used.

[0033] When the solid material is pulverized to a desired particle size, the particle size may be adjusted by a classification step, if necessary. For the classification step, for example, an elbow jet classifier using an inertial classification method, a microplex using a centrifugal classification method, or an airflow classifier may be used. Particles coarser than the desired particle size may be returned to the pulverization step for further pulverization. Particles finer than the desired particle size may be returned to the kneading step or melting step depending on the composition and reused.

[0034] In the spheronization step, the particles are preferably spheronized by heating. The spheronization device is not particularly limited, but examples thereof include a device for mechanically adjusting the particle shape, such as an impact spheronization device, a device for adjusting the particle shape by dissolving a binder and removing the solvent, such as a spray dryer, and a device for adjusting the particle shape by heating in a medium or using hot air. If necessary, a classification step can be carried out after the spheronization step.

[0035] <Cosmetics Containing Metal Soap Particles> The cosmetics of this embodiment contain the metal soap particles. Examples of cosmetics containing metal soap particles include makeup cosmetics such as foundation, liquid foundation, eye shadow, blush, face powder, concealer, blush, eyebrow powder, and highlighter; cleansing agents such as cleansers and facial washes; skin care cosmetics such as massage creams, moisturizing creams, and emulsions; body care cosmetics such as bath additives, sunscreens, sunscreen creams, and deodorant sprays; basic cosmetics such as makeup bases; and hair care cosmetics such as shampoos, conditioners, hair liquids, and hair colors. These cosmetics can be prepared by mixing and processing various raw materials in proportions appropriate for the intended use.

[0036] The cosmetic may contain metal soap particles in an amount ranging from 0.5% to 60% by mass relative to the total amount of the cosmetic. Preferably, the metal soap particles may be contained in an amount ranging from 1% to 40% by mass, and more preferably from 2% to 30% by mass relative to the total amount of the cosmetic. If the content of metal soap particles is less than 0.5% by mass, it is difficult to feel the effect of improving the skin feel when using the cosmetic. If the content exceeds 60% by mass, it is difficult to expect an effect commensurate with the amount blended, and problems may arise in maintaining the quality and stability of the cosmetic.

[0037] In addition to the metal soap particles, the cosmetic may contain various components conventionally used in cosmetics. Examples of such components include pigments, surface-treated pigments, UV absorbers, physiologically active ingredients, oils, surfactants, fluorine compounds, resins, thickeners, preservatives, fragrances, moisturizers, salts, solvents, antioxidants, chelating agents, neutralizing agents, pH adjusters, and insect repellents. These components may be added in amounts that do not impair the effects of the cosmetic of the present invention.

[0038] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0039] <Production of Metal Soap Particles> Metal soap particles containing fatty acid salts were produced by carrying out the following steps. (1) Pulverization step: A coarsely pulverized material containing raw materials such as fatty acid salts was finely pulverized using a jet mill (ULTRA SONIC JET MILL I-2, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to obtain a finely pulverized material having a volume-based average particle size of 0.5 to 200 μm. (2) Classification step: The finely pulverized material obtained in the pulverization step was passed through an air classifier (DS2UR, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to remove particles of 3 μm or less. (3) Spheronization step: The classified powder obtained in the classification step was treated in a hot-air spheronizer (Meteor Rainbow MR, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) heated to 360°C to spheronize it.

[0040] (Circularity) The circularity was measured using a flow particle image analyzer. The average circularity and the percentage (%) of particles having a circularity of 0.70 or less were calculated based on the number of particles.

[0041] (Particle size distribution) Particles were wetted with a surfactant, and then water was added to the resulting aqueous mixture, which was then passed through an ultrasonic disperser. A laser diffraction / scattering particle size distribution measuring device (Laser Micronsizer LMS-3000, manufactured by Malvern Panalytical) was used to measure the volume distribution by a wet method, thereby determining the median diameter (D50) and the particle diameter at 10% of the cumulative distribution function (D10).

[0042] <Skin feel: smooth feeling, moist feeling> The powder was placed on the skin on the inside of the arm and rubbed in a circle with a diameter of about 3 cm with the index finger of the opposite hand, and the feel felt with the index finger was evaluated according to the following criteria.

[0043] (Evaluation criteria for smooth feel) Spherical silica (Sunsphere (registered trademark) NP-100, manufactured by AGC Si-Tech) was used as the evaluation standard particles for smooth feel. 5: Very excellent = smooth feel clearly superior to the evaluation standard particles 4: Excellent = smooth feel slightly superior to the evaluation standard particles 3: Fair = smooth feel equivalent to the evaluation standard particles 2: Poor = smooth feel slightly inferior to the evaluation standard particles 1: Very poor = smooth feel clearly inferior to the evaluation standard particles

[0044] (Evaluation criteria for moist feeling) Boron nitride particles (SHP-3, manufactured by JFE Mineral) were used as the evaluation standard particles for moist feeling. 5: Very excellent = moist feeling clearly superior to the evaluation standard particles 4: Excellent = moist feeling slightly superior to the evaluation standard particles 3: Fair = moist feeling equivalent to the evaluation standard particles 2: Poor = moist feeling slightly inferior to the evaluation standard particles 1: Very poor = moist feeling clearly inferior to the evaluation standard particles

[0045] <Diffuse Reflectivity of Light> High diffuse reflectivity of light can be evaluated as an excellent soft focus effect. Diffuse reflectivity was measured using a three-dimensional variable goniophotometer GP-200 (manufactured by Murakami Color Research Laboratory) by irradiating light onto the sample and detecting the reflected and transmitted light with a photodetector that automatically moves in an arc, thereby measuring the reflection intensity and transmission intensity over a continuous light receiving angle. The incident angle was set to 45°, and the measurement was performed over a light receiving angle range of -90° to 90°.

[0046] Spherical silica (Sunsphere (registered trademark) NP-100, manufactured by AGC Si-Tech) was used as the standard particle for evaluation of diffuse reflectivity of light (soft focus effect). 5: Excellent = Larger arc size and spread than the standard particle 4: Excellent = Equivalent arc size and spread to the standard particle 3: Fair = Smaller arc size and spread than the standard particle

[0047] <Overall Evaluation> The overall evaluation of the metal soap particles was carried out by adding up the scores for the smooth feeling, the moist feeling, and the diffuse reflectivity of light. The evaluation criteria are as follows: Excellent: 13 to 15 points Good: 11 to 12 points Fair: 10 points Poor: 9 points or less

[0048] <Evaluation Results> The evaluation results are shown in Tables 1 to 3. In the "Fatty Acid Salt" column, the fatty acid salts are displayed by combining the name of the fatty acid with the metal element symbol, for example, "Ca stearate" represents "calcium stearate." Caprylic acid (8 carbon atoms), lauric acid (12 carbon atoms), palmitic acid (16 carbon atoms), stearic acid (18 carbon atoms), and behenic acid (22 carbon atoms) are straight-chain saturated fatty acids. Oleic acid (18 carbon atoms, 1 double bond) and linoleic acid (18 carbon atoms, 2 double bonds) are straight-chain unsaturated fatty acids.

[0049]

[0050]

[0051]

[0052] In Examples 1 to 16, the overall evaluation was 10 points or more (excellent, good, fair), and it was possible to simultaneously achieve (1) a smooth and moist feeling on the skin, and (2) an improved soft focus effect that makes wrinkles less noticeable. In Comparative Examples 1 to 5, the overall evaluation was 9 points or less (fail).

[0053] The metal soap particles of the present invention have a texture that is both smooth and moist, and can improve the soft focus effect that makes wrinkles and the like less noticeable, and can be used in the production of cosmetics.

Claims

1. Metal soap particles containing a fatty acid salt and no metal oxide, characterized in that the volume-based median diameter (D50) of the metal soap particles is 0.5 to 200 μm, the average circularity of the metal soap particles is 0.93 to 1.00, and the metal constituting the fatty acid salt is one or more selected from Mg, Ca, Zn, Ti, Al, Ba, Pb, Mo, Mn, and Fe.

2. Metal soap particles according to claim 1, characterized in that the fatty acid constituting the fatty acid salt is a saturated fatty acid.

3. Metal soap particles according to claim 2, characterized in that the fatty acid constituting the fatty acid salt is a saturated fatty acid having 12 to 22 carbon atoms.

4. Metal soap particles according to claim 1, characterized in that the ratio (D10 / D50) of the 10% diameter (D10) of the metal soap particles to the volume-based median diameter (D50) of the metal soap particles is 0.15 or more.

5. Metal soap particles according to claim 1, characterized in that the proportion of metal soap particles having a circularity of 0.70 or less is 20% or less on a number basis.

6. A method for producing metal soap particles according to claim 1, comprising: a grinding step for grinding a solid material of fatty acid salt; and a spheronization step for spheronizing the particles obtained in the grinding step.

7. The method for producing metal soap particles according to claim 6, characterized in that the spheronization step involves spheronizing the particles by heating.

8. A cosmetic comprising the metal soap particles according to any one of claims 1 to 5.

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