Soap composite particles, method for producing soap composite particles, and cosmetic

Abstract

The problem addressed by the present invention is to provide: soap composite particles that can both improve skin texture and sustain the functionality of the soap composite particles; a method for producing the soap composite particles; and a cosmetic containing the soap composite particles. These soap composite particles have core particles containing a saturated higher fatty acid salt and an inorganic oxide externally added to the core particles. In the core particles, the total content of Li2O, Na2O, Al2O3, MgO, CaO, ZnO, BaO, TiO2, SiO2, Fe3O4, Fe 2O3, and FeO is 0-15 mass%, and the core particles are spherical with a circularity of 0.80-1.00.

Description

Soap composite particles, method for producing soap composite particles, and cosmetics

[0001] The present invention relates to soap composite particles, a method for producing soap composite 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, Patent Document 1 does not state or suggest that an improvement in the feel to the skin and the durability of the function of the soap composite particles can be achieved at the same time.

[0005] When a cosmetic contains a paraffin-based solvent such as isododecane, the durability of the functionality of the metal soap particles may be affected compared to when a silicone-based solvent such as dimethicone is used.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide soap composite particles that can achieve both improved skin feel and sustained functionality of the soap composite particles, a method for producing the soap composite particles, and cosmetics containing the soap composite particles.

[0007] A first aspect of the present invention is a soap composite particle having a core particle containing a saturated higher fatty acid salt and an inorganic oxide externally added to the core particle, wherein the core particle is ２ O, Na ２ O, Al ２ O ３ , MgO, CaO, ZnO, BaO, TiO ２ , SiO ２ , Fe ３ O ４ , Fe ２ O ３The total content of FeO is 0 to 15 mass %, and the core particles are spherical with a circularity of 0.80 to 1.00.

[0008] In a second aspect, in the first aspect, the number of carbon atoms in the saturated higher fatty acid salt is in the range of 10 to 20. In a third aspect, in the first or second aspect, the metal forming the saturated higher fatty acid salt is one or more of Li, Na, Al, Mg, Ca, Zn, and Ba.

[0009] A fourth aspect is any one of aspects 1 to 3, wherein the amount of the inorganic oxide added externally relative to 100 parts by weight of the core particles is 0.01 to 15 parts by weight. A fifth aspect is any one of aspects 1 to 4, wherein the inorganic oxide is one or more of zinc oxide, magnesium oxide, titanium dioxide, mica, talc, kaolin, sericite, silica, iron oxide, alumina, zirconia, and zeolite.

[0010] In a sixth aspect, the inorganic oxide is subjected to a hydrophobic treatment in any one of the first to fifth aspects. In a seventh aspect, in the sixth aspect, the hydrophobic treatment is any one of a silane coupling treatment, a silicone oil treatment, a long-chain alkylsilane treatment, a fatty acid salt treatment, a long-chain alkane treatment, a long-chain alkene treatment, and a long-chain alkyne treatment.

[0011] In an eighth aspect, in any one of the first to seventh aspects, the inorganic oxide has an average primary particle size of 0.01 to 1.0 μm. In a ninth aspect, in any one of the first to eighth aspects, the core particle has a volume-based median diameter of more than 3 μm and less than 20 μm.

[0012] A tenth aspect is a method for producing soap composite particles according to any one of the first to ninth aspects, comprising a pulverization step of pulverizing a solid material of saturated higher fatty acid salt, a spheronization step of spheronizing the particles obtained in the pulverization step, and an external addition step of externally adding an inorganic oxide to the core particles obtained in the spheronization step. An eleventh aspect is a method for producing soap composite particles according to any one of the first to ninth aspects, comprising a pulverization step of pulverizing a solid material of saturated higher fatty acid salt, an external addition step of externally adding an inorganic oxide to the particles obtained in the pulverization step, and a spheronization step of spheronizing the particles obtained in the external addition step.

[0013] A twelfth aspect is a cosmetic preparation characterized by containing the soap composite particles of any one of the first to ninth aspects.

[0014] According to the present invention, it is possible to provide soap composite particles that can achieve both improved skin feel and sustained functionality of the soap composite particles, a method for producing the soap composite particles, and cosmetics containing the soap composite particles.

[0015] 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 configuration of the following embodiments are also included in the scope of the present invention.

[0016] The soap composite particle of this embodiment has a core particle containing a saturated higher fatty acid salt and an inorganic oxide externally added to the core particle.

[0017] <Saturated higher fatty acid salt> The core particles contain a saturated higher fatty acid salt. The saturated higher fatty acid salt may be an alkali metal salt such as sodium or potassium, or a metal salt other than an alkali metal salt. The saturated higher fatty acid salt may be produced by a conventional method using a saturated higher fatty acid or its alkali metal salt and inorganic metal salt as a raw material, or a commercially available product may be used. The saturated higher fatty acid salt may be one type or a mixture of two or more types.

[0018] The saturated higher fatty acid used in the saturated higher fatty acid salt is not particularly limited, but preferred examples 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, and montanic acid.

[0019] 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 rays, and tend to maintain excellent quality. The saturated higher fatty acid salts may be branched, but saturated higher fatty acid salts having a branched side chain with two or fewer carbon atoms 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.

[0020] When the saturated higher fatty acid salt is a straight-chain 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 soap composite particles, and the high melting point makes it difficult to become liquid at room temperature (5 to 35°C), making it easy to maintain excellent quality.

[0021] The number of carbon atoms in the saturated higher fatty acid salt is not particularly limited, but may be, for example, within the range of 8 to 30, preferably within the range of 10 to 20, more preferably within the range of 10 to 18, and particularly preferably within the range of 10 to 16. When the number of carbon atoms is equal to or greater than the lower limit, the saturated higher fatty acid salt exhibits hydrophobicity and is less susceptible to the effects of moisture. When the number of carbon atoms is equal to or less than the upper limit, the molecules are more likely to align, the structure is stable, the melting point is higher, and the shape of the core particles is stabilized. Furthermore, the durability of the inorganic oxide function is improved.

[0022] The metal salt used for the saturated higher fatty acid salt is not particularly limited, but examples thereof include alkali metal salts, alkaline earth metal salts, and transition metal salts. Metals forming the saturated higher fatty acid salt include one or more of Li, Na, Al, Mg, Ca, Zn, and Ba, preferably one or more of Zn, Mg, Ca, and Al, and more preferably one or more of Zn, Mg, and Ca. These compounds form a stable structure in the soap itself. Among these, it is preferable to select a compound that has little effect on the human body and is insoluble in water.

[0023] In particular, when a composition containing the soap composite particles is applied to the skin, it is preferable that the molecular ends of the saturated higher fatty acid salt form a uniform hydrophobic surface. This makes the composition less susceptible to the effects of moisture in the air and moisture in body fluids such as sweat, improving the feel on the skin. Applications of compositions applied to the skin include cosmetics, pharmaceuticals, and other drugs.

[0024] The saturated higher fatty acid salt has a carboxylate ion group (—COO － It is preferable that the saturated higher fatty acid salt does not contain polar functional groups such as hydroxyl groups or epoxy groups, except for the above-mentioned group (RCOO). This improves the hydrophobicity. The general formula of the saturated higher fatty acid salt is (RCOO) ｍ When represented by M, at least a part or all of the saturated higher 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 As for the branched alkyl group, the branch is preferably located at a position away from the carboxylate ion group, for example, (CH ３ ) ２ CH (CH ２ ) ｎ－４ -, etc. ｎ－１ H ２ｎ－１ COO) ｍ It is preferable that the compound contains a non-cyclic compound represented by the general formula [CH ３ (CH ２ ) ｎ－２ COO] ｍIt is more preferable that the compound contains a linear compound represented by M. In these general formulas, n represents the number of carbon atoms, and M represents a metal.

[0025] When the metal M of the saturated higher fatty acid salt is polyvalent, that is, when m is 2 or greater, the carbon number n of the m saturated higher fatty acids may be the same or different. When the carbon numbers n of the m saturated higher fatty acids are different, the difference between the maximum carbon number and the minimum carbon number is preferably 4 or less, and more preferably 2 or less. In order for the molecular ends of the saturated higher fatty acid salt to form a more uniform hydrophobic surface, it is preferable that the carbon numbers of the saturated higher fatty acids constituting the saturated higher fatty acid salt are the same.

[0026] <Core Particles> The core particles have a spherical shape with a circularity of 0.80 to 1.00. It is more preferable that the circularity of the core particles is 0.90 to 1.00. The saturated higher fatty acid salt of the core particles acts as a lubricant, making them easier to roll without resistance. When the circularity of the core particles is equal to or greater than the lower limit, the particles roll easily without resistance. For example, when a composition containing soap composite particles is applied to the skin using the finger pads, the particles roll easily, allowing for a favorable effect on the skin. The theoretical maximum circularity is 1, which corresponds to the case where the particle image is a perfect circle.

[0027] 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

[0028] 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.

[0029] In the soap composite particle of this embodiment, Li 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 , and FeO in a total content of 0 to 15 mass %. These metal oxides (hereinafter sometimes referred to as "specific metal oxides") may be derived from an inorganic oxide externally added to the core particles, may be derived from an inorganic oxide internally added to the core particles, or may be derived from a saturated higher fatty acid salt. The specific metal oxide may be different from the inorganic oxide externally added to the core particles, or may be different from the inorganic oxide internally added to the core particles.

[0030] When the core particles do not contain the specific metal oxide, it is preferable that no inorganic oxide is added to the core particles or that an inorganic oxide different from the specific metal oxide is added to the core particles. In this case, the content (total content) of the specific metal oxide in the core particles may be 0% by weight, but the specific metal oxide may be mixed into the core particles as an impurity, or part of the inorganic oxide added externally to the core particles may be contained in the core particles.

[0031] When the core particle contains a specific metal oxide, the inorganic oxide added to the core particle preferably contains the specific metal oxide. In this case, the content (total content) of the specific metal oxide in the core particle is preferably 0.01 wt % or more.

[0032] Among them, the specific metal oxide is Al ２ O ３ , MgO, ZnO, TiO ２ , SiO ２ , Fe ３ O ４ , Fe ２ O ３ When the inorganic oxide is FeO, which is preferably added externally or internally to the core particles and also serves as a functional inorganic oxide, the content thereof is preferably 0.01% by weight or more, thereby enabling the functionality of the inorganic oxide to be exerted and improving the durability.

[0033] The metals contained in the specific metal oxide (Li, Na, Al, Mg, Ca, Zn, Ba, Ti, Si, Fe) may be the same as the metals forming the saturated higher fatty acid salt (preferably Li, Na, Al, Mg, Ca, Zn, Ba). When the content of the specific metal oxide in the core particle is equal to or less than the upper limit, the crystallinity of the saturated higher fatty acid salt is more easily maintained. This makes it easier to maintain the shape of the core particle, improving the feel on the skin. When the metal contained in the specific metal oxide and the metal forming the saturated higher fatty acid salt are each selected from the group consisting of Li, Na, Al, Mg, Ca, Zn, and Ba, different metals may be selected.

[0034] The volumetric median diameter of the core particles is preferably more than 3 μm and less than 20 μm, more preferably more than 5 μm and less than 15 μm, and even more preferably more than 7 μm and less than 10 μm. If the volumetric median diameter of the core particles exceeds the lower limit, the particles have a low cohesive force and are less likely to form clumps. If the volumetric median diameter of the core particles is less than the upper limit, the surface area per unit weight increases, increasing the exposed area of ​​the inorganic oxide and improving the durability of the inorganic oxide function.

[0035] In applications where the composition containing the soap composite particles is applied to the skin, if the volume-based median diameter of the core particles is above the lower limit, the particles spread easily on the skin and provide a uniform feel when spread. On the other hand, if the volume-based median diameter of the core particles is below the upper limit, the roughness caused by the particle size is less felt on the fingertips, improving the feel on the skin.

[0036] <Inorganic Oxide> The soap composite particle of the embodiment has an inorganic oxide externally added to a core particle. As described above, the core particle is not particularly limited as long as it has a structure containing a saturated higher fatty acid salt, but an inorganic oxide may be internally added to the core particle. The inorganic oxide internally added to the core particle may be embedded within the core particle. It is preferable that the inorganic oxide externally added to the core particle covers at least a portion of the outer surface of the core particle.

[0037] Examples of the inorganic oxide include inorganic particles of metal oxides, metal nitrides, silicates, sulfates, carbonates, phosphates, etc. Specific examples of the inorganic oxide include one or more of zinc oxide, magnesium oxide, titanium dioxide, mica, talc, kaolin, sericite, silica, iron oxide, alumina, zirconia, and zeolite.

[0038] The inorganic oxide particles are preferably functional particles. The functionality is preferably such that, when the soap composite particles are used, the inorganic oxide particles act on an object together with the saturated higher fatty acid salt. Specific examples of the functionality include, but are not limited to, UV reflectivity, sunscreen, hiding power as a pigment, anti-inflammatory properties, X-ray absorption, solid lubricity, releasability, antibacterial properties, and electrical insulation.

[0039] The content of inorganic oxide in the soap composite particles (total amount of internally added and externally added) is preferably 3 to 80 wt %. When the total amount is equal to or greater than the lower limit, the exposed area of ​​the inorganic oxide increases, improving the durability of the inorganic oxide's function. When the total amount is equal to or less than the upper limit, the bond between the saturated higher fatty acid salt and the inorganic oxide becomes stable, improving the uniformity of the soap composite particles.

[0040] The content (internal addition amount) of the inorganic oxide in the core particles is preferably 5 to 75 wt %, more preferably 5 to 10 wt %. When the internal addition amount is equal to or greater than the lower limit, the exposed area of ​​the inorganic oxide increases, improving the durability of the inorganic oxide function. When the internal addition amount is equal to or less than the upper limit, kneading of the saturated higher fatty acid salt and the inorganic oxide becomes easy, improving the uniformity of the core particles.

[0041] The amount of inorganic oxide added externally per 100 parts by weight of the core particles is preferably 0.01 to 15 parts by weight, more preferably 0.05 to 8.0 parts by weight. When the amount added externally is equal to or greater than the lower limit, the amount of inorganic oxide present on the surface of the core particles increases, improving the durability of the inorganic oxide's function. When the amount added externally is equal to or less than the upper limit, the lubricity and feel characteristic of saturated higher fatty acid salts become more dominant.

[0042] The inorganic oxide externally added to the core particles may be the same type of inorganic oxide as the inorganic oxide internally added to the core particles, or may be a different inorganic oxide. One type of inorganic oxide may be internally added to the core particles, or two or more types may be internally added. When two or more types of inorganic oxides are internally added to the core particles, the amount internally added may be the total amount of the two or more types. One type of inorganic oxide may be externally added to the core particles, or two or more types may be externally added. When two or more types of inorganic oxides are externally added to the core particles, the amount externally added may be the total amount of the two or more types.

[0043] The inorganic oxide externally added to the core particles may function as a fluidity imparting agent. In this case, the fluidity imparting agent exerts a bearing effect, increasing the fluidity of the soap composite particles and improving the feel on the skin. As the inorganic oxide externally added to the core particles, particles that function as a fluidity imparting agent may be used in combination with particles having other functions.

[0044] The inorganic oxides added externally and / or internally to the core particles may be coated, for example, may be subjected to a hydrophobic treatment. The hydrophobic treatment is not particularly limited, but may include silane coupling treatment, silicone oil treatment, long-chain alkylsilane treatment, fatty acid salt treatment, long-chain alkane treatment, long-chain alkene treatment, and long-chain alkyne treatment. In the silicone oil treatment, modified silicone oil may be used.

[0045] In the case of silane coupling treatment or silicone oil treatment, siloxane bonds are formed and fixed on the surface of the inorganic oxide by hydrolysis and dehydration condensation reaction of the silane coupling agent or silicone oil, and the inorganic oxide is made hydrophobic. Therefore, the inorganic oxide has high dispersibility even when kneaded into soap made of hydrophobic higher saturated fatty acid salt at high temperature.

[0046] In the case of fatty acid salt treatment, the composition of the fatty acid salt is the same as or similar to the composition of the higher saturated fatty acid salt used in soap. Therefore, inorganic oxides surface-treated with fatty acid salts have high dispersibility in the soap they are kneaded into and high adhesion to the soap. Note that when the fatty acid salt used in the fatty acid salt treatment corresponds to the above-mentioned higher saturated fatty acid salt, its mass may be excluded from the mass of the inorganic oxide and added to the mass of the higher saturated fatty acid salt.

[0047] In the case of long-chain alkylsilane treatment, long-chain alkane treatment, long-chain alkene treatment, or long-chain alkyne treatment, the inorganic oxide can be hydrophobized by using a corresponding long-chain aliphatic compound. The chain length of these long-chain aliphatic compounds is not particularly limited, but may be, for example, 8 to 30 carbon atoms.

[0048] The average primary particle size of the inorganic oxide externally and / or internally added to the core particles is preferably 0.01 to 1.0 μm. When the average primary particle size of the inorganic oxide is equal to or greater than the lower limit, the inorganic oxide particles are less likely to aggregate and are more easily dispersed. In particular, when such an inorganic oxide is externally added, the feel of the soap composite particles is improved. When the average primary particle size of the inorganic oxide is equal to or less than the upper limit, the inorganic oxide is more likely to be internally added to the core particles, and even when externally added, it is less likely to fall off from the soap composite particles. In particular, when such an inorganic oxide is externally added, the bumpy feel of the inorganic oxide (surface roughness due to the particles) is reduced, and the feel of the soap composite particles is improved.

[0049] <Method for producing soap composite particles> The soap composite particles of this embodiment can be produced, for example, through a pulverization step of a saturated higher fatty acid salt, an external addition step of externally adding an inorganic oxide to core particles, and a spheronization step of the core particles. The spheronization step can be carried out before or after the external addition step.

[0050] When the spheronization step is carried out before the external addition step, the production method preferably comprises a pulverization step of pulverizing a solid material of the saturated higher fatty acid salt, a spheronization step of spheronizing the particles obtained in the pulverization step, and an external addition step of externally adding an inorganic oxide to the core particles obtained in the spheronization step.When the spheronization step is carried out after the external addition step, the production method preferably comprises a pulverization step of pulverizing a solid material of the saturated higher fatty acid salt, an external addition step of externally adding an inorganic oxide to the particles obtained in the pulverization step, and a spheronization step of spheronizing the particles obtained in the external addition step.

[0051] When an inorganic oxide is added to the core particles, it is preferable to have a kneading step of melting and kneading a mixed powder of a saturated higher fatty acid salt and an inorganic oxide before the pulverization step. When an inorganic oxide is not added to the core particles, it is preferable to heat and melt the saturated higher fatty acid salt to obtain a solid product of the saturated higher fatty acid salt.

[0052] When an inorganic oxide is added to the core particles, the kneading step may be preceded by a measuring step of measuring the saturated higher fatty acid salt and the inorganic oxide to be used in preparing the core particles, and a mixing step of stirring and mixing the measured saturated higher fatty acid salt and the inorganic oxide. For mixing the particles, a mixing device such as a double-cone mixer, a V-type mixer, a drum mixer, a super mixer, a Henschel mixer, or a Nauta mixer may be used, although it is not particularly limited.

[0053] Although it is possible to mix some of the raw materials during the kneading step, it is preferable to premix at least some of the raw materials before the kneading step. Premixing is advantageous in controlling the composition of the saturated higher fatty acid salt and inorganic oxide, the particle size, shape, etc.

[0054] The kneading step is preferably carried out under conditions in which the saturated higher fatty acid salt is melted or softened by heating. As a result, the inorganic oxide mixed with the saturated higher fatty acid salt is internally added to the saturated higher fatty acid salt. The kneading machine 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 saturated higher fatty acid salt, and may be, for example, about 80 to 250°C, about 100 to 200°C, or 100 to 140°C.

[0055] When a kneading step of a saturated higher fatty acid salt and an inorganic oxide or a melting step of a saturated higher 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, or the like.

[0056] 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.

[0057] 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.

[0058] The spheronization step is a step of spheronizing particles by heating. The spheronization device is not particularly limited, but examples include devices that mechanically adjust particle shape, such as impact spheronization devices; devices that adjust particle shape by binder dissolution and solvent removal, such as spray drying devices; and devices that adjust particle shape by heating in a medium or using hot air. When the spheronization step is performed before the external addition step, spherical core particles are obtained by the spheronization step. When the spheronization step is performed after the external addition step, soap composite particles in which core particles have become spherical are obtained by the spheronization step. If necessary, a classification step can be performed after the spheronization step.

[0059] In the external addition step, the inorganic oxide is externally added to the core particles by mixing the inorganic oxide with the core particles. For the external addition step of the inorganic oxide, a mixing device such as a Super Mixer or a Henschel Mixer may be used, or a powder processing device such as a Mechano Mill may be used.

[0060] <Soap composite particles> The soap composite particles of the embodiment have the functionality of the saturated higher fatty acid salt as well as the functionality of the internally or externally added inorganic oxide, and therefore can be used as various functional materials. The uses of the soap composite particles are not particularly limited, but examples include use as a feel improver, lubricant, release agent, anti-caking agent, cosmetic raw material, colorant, processing aid, dispersant, additive, etc.

[0061] <Method for analyzing soap composite particles> As described above, the soap composite particles of the embodiment have core particles containing saturated higher fatty acid salts and inorganic oxides externally added to the core particles. Since the core particles are mainly composed of saturated higher fatty acid salts, it is possible to separate the saturated higher fatty acid salts from the inorganic oxides. This makes it possible to evaluate the amounts of internal and external addition even if the inorganic oxides internally added to the core particles and the inorganic oxides externally added to the core particles are the same substance.

[0062] A specific example of a method for separating the core particles from the external additives (externally added inorganic oxides) is to add a pre-weighed amount of soap composite particle powder to a dispersion medium, insert the probe of an ultrasonic homogenizer into the resulting dispersion, and irradiate it with ultrasonic waves. This allows the external additives that have fallen off the core particles to suspend in the dispersion medium. After allowing the core particles to settle by standing or centrifuging, the supernatant liquid in which the external additives are suspended can be extracted and separated by a liquid separation operation, etc.

[0063] The dispersion medium is preferably an aqueous solution prepared by dissolving a surfactant in water to prevent the powder from agglomerating. Because the saturated higher fatty acid salt is insoluble in water, the added inorganic oxide can be maintained in a state of being enclosed in the core particles.

[0064] The amount of core particles from which the external additives have been separated can be determined by repeatedly washing the sediment with a solvent and filtering it using filter paper capable of capturing the core particles, then drying and weighing the sediment. The filter paper's collection performance is preferably such that it can retain particles of, for example, 1 μm or larger. The amount of external additives may be calculated by subtracting the mass of the core particles obtained by weighing from the mass of the soap composite particles.

[0065] The components and composition of the external additives contained in the supernatant can be analyzed, for example, by X-ray fluorescence analysis (XRF) of the supernatant.The components and composition of the inorganic oxides internally added to the core particles can be analyzed, for example, by X-ray fluorescence analysis (XRF) of the core particles obtained as precipitates.

[0066] <Cosmetics Comprising Soap Composite Particles> The cosmetics of this embodiment contain the soap composite particles. Examples of cosmetics containing soap composite 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.

[0067] The cosmetic can contain the soap composite particles in an amount ranging from 0.5% to 60% by mass relative to the total amount of the cosmetic. Preferably, the soap composite particles can 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 the soap composite 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.

[0068] In addition to the soap composite particles, the cosmetic may contain various ingredients conventionally used in cosmetics. Examples 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 ingredients may be added in amounts that do not impair the effects of the cosmetic of the present invention.

[0069] The cosmetic may contain a paraffin-based solvent such as isododecane. Because the surface of the core particle is hydrophobic, the soap composite particles are less likely to drop off, resulting in excellent durability of the metal soap particle function. Furthermore, when the surface of the inorganic oxide is hydrophobized, the affinity of the inorganic oxide to the surface of the core particle is further increased, further suppressing dropout of the inorganic oxide particles.

[0070] The present invention has been described above based on preferred embodiments, but the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present invention.

[0071] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0072] <Production of Soap Composite Particles> Soap composite particles in which an inorganic oxide was externally added to core particles containing a saturated higher fatty acid salt and an inorganic oxide were produced by carrying out the following steps.

[0073] (Mixing Step) As shown in the "Saturated higher fatty acid salt" and "Internal inorganic oxide" columns of Tables 1 to 4, the saturated higher fatty acid salt and the inorganic oxide were each weighed, placed in a 20 L Henschel mixer (FM20 manufactured by Nippon Coke and Engineering Co., Ltd.), and mixed by stirring to obtain a mixed powder.

[0074] (Kneading step) The mixed powder obtained in the mixing step was melt-kneaded by heating to 100 to 140° C. in a twin-screw kneader (PCM-30 manufactured by Ikegai Corporation). The molten kneaded product discharged from the kneader was passed through a cooled rolling mill to obtain a plate-shaped solid kneaded product.

[0075] The plate-like solid kneaded product obtained in the mixing step was coarsely pulverized using a hammer mill to obtain a coarsely pulverized product of 0.5 to 3.0 mm. The coarsely pulverized product was then finely pulverized using a jet mill (Ultra Sonic Jet Mill I-2, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to obtain a finely pulverized product having a volume-based average particle size of 3 to 20 μm.

[0076] (Classification Step) The finely pulverized material obtained in the pulverization step was subjected to an air classifier (DS2UR manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to remove particles of 3 μm or less.

[0077] (Spheronization Step) The classified powder obtained in the classification step was stirred for 20 minutes in a jacketed Henschel mixer 10 L (FM10 manufactured by Nippon Coke) through which hot water heated to 60 to 90° C. was passed, to form spheroids.

[0078] (External Addition Step) To the spherical core particles obtained in the spheronization step, inorganic oxides were externally added as shown in "Externally Added Inorganic Oxides" in Tables 1 to 4 to obtain soap composite particles.

[0079] <Core Particle Structure> The spherical core particles obtained in the spheronization step were used as samples to measure the structure of the core particles by the following method. Note that core particles separated from external additives using the above-mentioned method for analyzing soap composite particles can also be used as samples.

[0080] (Circularity) The circularity of the core particles was measured using a flow-type particle image analyzer.

[0081] (Volume-Based Median Diameter) The median diameter (D50) was determined by measuring the volume distribution using a Coulter counter, utilizing the electrical change that occurs when the core particles pass through an aperture tube.

[0082] <Method for evaluating skin texture> An earpick-sized amount of soap composite particle powder was placed on the wrist of one arm, and the powder was gently rolled over the skin with the middle finger of the other hand, moving in a circle with a diameter of 4 cm for 15 seconds, and the texture was evaluated using the middle finger and wrist. Four evaluation panelists (two adult males and two adult females) classified the usability into each category and gave each category a score for a sensory evaluation. The evaluation items and evaluation criteria are as follows:

[0083] (Evaluation items for skin feel) Spreadability: Whether the powder spreads well on the skin when applied. Stickiness: Whether the powder fills well into pores when applied. Smoothness: Whether the powder feels good on the skin when applied and after application. Lightness: Whether the powder feels light after application when applied. Staying power: Whether the makeup stays well when rubbing the powder with your fingers after application. Softness: Whether the powder feels good soft when applied and after application.

[0084] (Evaluation criteria for texture) 5: Very good 4: Good 3: Fair 2: Poor 1: Very poor

[0085] <Development of Function> The development of the function of the inorganic oxide was evaluated for each type of inorganic oxide according to the following evaluation criteria.

[0086] (Evaluation criteria for the expression of functions) 5: The function of inorganic oxide is expressed. 3: The function of inorganic oxide is slightly expressed. 1: The function of inorganic oxide is not expressed.

[0087] <Function Durability> 9.5 g of a volatile organic solvent used in cosmetics was placed in a sample bottle, and 0.5 g of soap composite particle powder was added thereto. The bottle was then capped and placed on a vibration table for stirring, after which it was left to stand for 24 hours in a room at 20°C. The humidity was set within the normal humidity range (45-85% RH). The particle shape was observed with an optical microscope to see if it had changed from the shape before immersion in the solvent. The function durability was evaluated according to the following evaluation criteria.

[0088] (Evaluation criteria for durability of function) 5: No change at all in the shape of the soap composite particles. 3: Partial change in the shape of the soap composite particles. 1: Change in the shape of the soap composite particles.

[0089] <Overall Evaluation> The overall evaluation was made based on the total score obtained from the three items of (1) feel on the skin, (2) expression of function, and (3) durability of function, and was evaluated according to the following evaluation criteria.

[0090] (Evaluation criteria for overall evaluation) +++: The total score was 15. ++: The total score was 13 or 14. +: The total score was 11 or 12. -: The total score was less than 11.

[0091] <Evaluation Results> The evaluation results are shown in Tables 1 to 4. In the "Saturated higher fatty acid salt" column, the fatty acid salt is displayed by combining the name of the fatty acid with the element symbol of the metal, for example, "Ca stearate" represents "calcium stearate." In some comparative examples, unsaturated fatty acid salts were used.

[0092] Stearic acid (18 carbon atoms), lauric acid (12 carbon atoms), palmitic acid (16 carbon atoms), caprylic acid (8 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.

[0093] The weight parts in Tables 1 to 4 were set so that the total of the saturated higher fatty acid salt and the internally added amount of inorganic oxide was 100 parts by weight. Therefore, the value of the internally added amount of inorganic oxide (parts by weight) is equal to the value of the content (wt%) of inorganic oxide in the core particles.

[0094] In the "Hydrophobic Treatment" column of Tables 1 to 4, the inorganic oxide that was not hydrophobic treated is indicated as "None," the silane coupling treatment is indicated as "SiCp," and the silicone oil treatment is indicated as "SiOi."

[0095]

[0096]

[0097]

[0098]

[0099] In Examples 1 to 26, the overall evaluation was +++, ++, or +, and it was possible to achieve both an improvement in skin feel and durability of the function of the soap composite particles. In Comparative Examples 1 to 4, the overall evaluation was -. In Comparative Example 1, the content of the specific metal oxide in the core particles was more than 10 mass%, and the durability of function was rated 1. In Comparative Example 2, the circularity was less than 0.80, and the durability of function was rated 1. In Comparative Examples 3 and 4, an unsaturated fatty acid salt was used instead of a saturated higher fatty acid salt, but the evaluation of skin feel was low.

[0100] The soap composite particles of the present invention can achieve both an improvement in skin feel and durability of the inorganic oxide function, and can be used in the production of cosmetics.

Claims

1. A soap composite particle having core particles containing a saturated higher fatty acid salt and an inorganic oxide externally added to the core particles, wherein in the core particles, Li 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 , and the total content rate of FeO is 0 to 15% by mass, and the shape of the core particles is spherical with a circularity of 0.80 to 1.

00. A soap composite particle characterized by the above.

2. The soap composite particles according to claim 1, wherein the saturated higher fatty acid salt has 10 to 20 carbon atoms.

3. The soap composite particles according to claim 1, wherein the metal forming the saturated higher fatty acid salt is any one or more of Li, Na, Al, Mg, Ca, Zn, and Ba.

4. The soap composite particles according to claim 1, wherein the addition amount of the inorganic oxide to 100 parts by weight of the core particles is 0.01 to 15 parts by weight.

5. The soap composite particles according to claim 1, wherein the inorganic oxide is any one or more of zinc oxide, magnesium oxide, titanium dioxide, mica, talc, kaolin, sericite, silica, iron oxide, alumina, zirconia, and zeolite.

6. The soap composite particles according to claim 1, wherein the inorganic oxide is hydrophobically treated.

7. The soap composite particles according to claim 6, wherein the hydrophobization treatment is any one of a silane coupling treatment, a silicone oil treatment, a long-chain alkylsilane treatment, a fatty acid salt treatment, a long-chain alkane treatment, a long-chain alkene treatment, and a long-chain alkyne treatment.

8. The soap composite particles according to claim 1, wherein the average primary particle size of the inorganic oxide is 0.01 to 1.0 μm.

9. The soap composite particles according to claim 1, wherein the volume-based median diameter of the core particles is more than 3 μm and less than 20 μm.

10. A method for producing the soap composite particles according to claim 1, comprising: a pulverization step of pulverizing a solid of a saturated higher fatty acid salt; a spheroidization step of spheroidizing the particles obtained in the pulverization step; and an addition step of externally adding an inorganic oxide to the core particles obtained in the spheroidization step.

11. A method for producing the soap composite particles according to claim 1, comprising: a pulverization step of pulverizing a solid of a saturated higher fatty acid salt; an addition step of externally adding an inorganic oxide to the particles obtained in the pulverization step; and a spheroidization step of spheroidizing the particles obtained in the addition step.

12. A cosmetic comprising the soap composite particles according to any one of claims 1 to 9.

Images