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

Abstract

The technical problem of this invention is to provide soap composite particles that can achieve both improved skin feel and sustained functionality of soap composite particles, a method for manufacturing the soap composite particles, and a cosmetic product containing the soap composite particles. The soap composite particles of this invention have core particles containing saturated higher fatty acid salts and inorganic oxides added to the core particles. The total content of Li₂O, Na₂O, Al₂O₃, MgO, CaO, ZnO, BaO, TiO₂, SiO₂, Fe₃O₄, Fe₂O₃, and FeO in the core particles is 0-15% by mass, and the shape of the core particles is spherical with a sphericity of 0.80-1.00.

Description

Technical Field

[0001] This invention relates to soap composite particles, a method for manufacturing soap composite particles, and cosmetics. Background Technology

[0002] Patent Document 1 discloses a metallic soap capable of imparting high dispersibility or coating properties to powders, improving the powder's anti-caking properties, flowability, or tactile feel, and a method for manufacturing the same. This metallic soap is characterized in that the internal intake rate A, defined as the proportion of inorganic crystal nucleating agents incorporated into the interior of the metallic soap particles, is 30% or more.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 6729546. Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] Patent Document 1 suggests that the inorganic crystallizing nucleating agent ingested into the interior of the metal soap particles results in uniform particle shape and sharp particle size distribution, thus improving the tactile feel of the solid powder cosmetic in the embodiment. However, Reference 1 neither describes nor suggests the simultaneous improvement in skin feel and the persistence of the function of the soap complex particles.

[0008] In cosmetics containing paraffin-based solvents such as isododecane, the functionality of metal soap particles may be affected compared to that of organosilicon-based solvents such as polydimethylsiloxane.

[0009] The present invention was made in view of the above circumstances, and its technical problem is to provide a soap compound that can achieve both improved skin feel and the function of soap compound particles, a method for manufacturing the soap compound particles, and a cosmetic containing the soap compound particles.

[0010] Means for solving technical problems

[0011] The 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 added to the core particle. The total content of Li2O, Na2O, Al2O3, MgO, CaO, ZnO, BaO, TiO2, SiO2, Fe3O4, Fe2O3, and FeO in the core particle is 0 to 15% by mass, and the shape of the core particle is a sphere with a sphericity of 0.80 to 1.00.

[0012] The second method is the same as the first method, where the number of carbon atoms in the aforementioned saturated higher fatty acid salts is in the range of 10 to 20.

[0013] The third method is that, in the first or second method, the metal that forms the above-mentioned saturated higher fatty acid salt is any one or more of Li, Na, Al, Mg, Ca, Zn, and Ba.

[0014] The fourth method is in any of the first to third methods, where the amount of the inorganic oxide added relative to 100 parts by weight of the nuclear particles is 0.01 to 15 parts by weight.

[0015] The fifth method is any one or more of the inorganic oxides mentioned in any of the first to fourth methods, namely zinc oxide, magnesium oxide, titanium dioxide, mica, talc, kaolin, sericite, silicon dioxide, iron oxide, aluminum oxide, zirconium oxide, and zeolite.

[0016] The sixth method is in any of the first to fifth methods, where the aforementioned inorganic oxide is hydrophobically treated.

[0017] The seventh method is the same as the sixth method, where the hydrophobic treatment mentioned above is any one of silane coupling treatment, silicone oil treatment, long-chain alkylsilane treatment, fatty acid salt treatment, long-chain alkane treatment, long-chain olefin treatment, or long-chain alkyne treatment.

[0018] The eighth method is in any of the first to seventh methods, where the average primary particle size of the aforementioned inorganic oxide is 0.01 to 1.0 μm.

[0019] The ninth mode is in any of the first to eighth modes, where the median particle size of the aforementioned nuclear particles exceeds 3 μm and is less than 20 μm in volume reference.

[0020] The tenth method is a method for manufacturing soap composite particles according to any one of the first to ninth methods, comprising: a pulverizing step, pulverizing a solid substance of saturated higher fatty acid salt; a spheroidizing step, spheroidizing the particles obtained in the pulverizing step; and an external addition step, externally adding an inorganic oxide to the core particles obtained in the spheroidizing step.

[0021] The eleventh method is a method for manufacturing soap composite particles according to any one of the first to ninth methods, comprising: a pulverizing step, pulverizing a solid substance of saturated higher fatty acid salt; an external addition step, externally adding an inorganic oxide to the particles obtained in the pulverizing step; and a spheroidizing step, spheroidizing the particles obtained in the external addition step.

[0022] The twelfth method is a cosmetic product characterized by incorporating soap complex particles from any one of the first to ninth methods.

[0023] The effects of the invention

[0024] According to the present invention, a soap compound particle capable of achieving both improved skin feel and sustained functionality of the soap compound particle is provided, a method for manufacturing the soap compound particle, and a cosmetic comprising the soap compound particle are provided. Detailed Implementation

[0025] The present invention will now be described using embodiments. However, these embodiments are specific examples provided to better understand the spirit of the invention and, unless otherwise specified, do not constitute a limitation thereof. Other embodiments obtained by those skilled in the art through appropriate substitutions of the structures of the following embodiments are also included within the scope of the present invention.

[0026] The soap composite particles of this embodiment have core particles containing saturated higher fatty acid salts and inorganic oxides added to the core particles.

[0027] <Saturated higher fatty acid salts>

[0028] Nuclear particles contain saturated higher fatty acid salts. These saturated higher fatty acid salts can be alkali metal salts such as sodium and potassium, or metal salts other than alkali metals. Saturated higher fatty acid salts can be manufactured using conventional methods from saturated higher fatty acids or their alkali metal salts and inorganic metal salts, or commercially available saturated higher fatty acid salts can be used. Saturated higher fatty acid salts can be one type or a mixture of two or more types.

[0029] The saturated higher fatty acid used in the saturated higher fatty acid salt is not particularly limited, but is preferably hexanoic acid, caproic acid, heptanoic acid, octanoic acid, caprylic acid, nonanoic acid, decanoic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, limonitic acid, etc.

[0030] Saturated higher fatty acids, lacking double bonds (unsaturated bonds) in their hydrocarbon chains, exhibit high chemical stability and are not easily degraded by oxygen or ultraviolet light, thus maintaining their excellent quality. Saturated higher fatty acid salts can also be branched, but it is preferable that the side chains of the branched chains contain two or fewer carbon atoms, more preferably saturated higher fatty acid salts with one or fewer carbon atoms. Straight-chain saturated higher fatty acid salts are particularly preferred.

[0031] When the saturated higher fatty acid salt is a straight-chain saturated higher fatty acid salt, it has a stable structure because it does not have double bonds (unsaturated bonds) or side chains in the hydrocarbon chain. In addition, because the methyl groups at the molecular ends are neatly arranged on the surface of the soap composite particles, the melting point is high, so it is difficult to become liquid at room temperature (5-35°C), and it is easy to maintain excellent quality.

[0032] The number of carbon atoms in the saturated higher fatty acid salt is not particularly limited, but can be in the range of 8 to 30, preferably in the range of 10 to 20, more preferably in the range of 10 to 18, and particularly preferably in the range of 10 to 16. When the number of carbon atoms is above the lower limit, the saturated higher fatty acid salt exhibits hydrophobicity and is less susceptible to the influence of moisture. When the number of carbon atoms is below the upper limit, the molecules become easier to arrange, the structure is stable, the melting point becomes higher, and the shape of the nuclei becomes more stable. Furthermore, the sustainability of the inorganic oxide's function is improved.

[0033] The metal salt used in the saturated higher fatty acid salt is not particularly limited, and examples include alkali metal salts, alkaline earth metal salts, and transition metal salts. The metal that forms the saturated higher fatty acid salt can be any one or more of Li, Na, Al, Mg, Ca, Zn, and Ba, preferably any one or more of Zn, Mg, Ca, and Al, and more preferably any one or more of Zn, Mg, and Ca. These compounds form a stable structure within the soap itself. Among them, compounds with minimal impact on the human body and insoluble in water are preferred.

[0034] In particular, in the application of the composition containing the soap complex particles to the skin, it is preferable that the molecular ends of the saturated higher fatty acid salt form a uniform hydrophobic surface. This makes it less susceptible to the effects of moisture in the air, sweat, and other bodily fluids, thus improving skin feel. Examples of applications for the composition to the skin include cosmetics, pharmaceuticals, and other medications.

[0035] The saturated higher fatty acid salts, in addition to having a carboxylic acid ion group (-COO) at one end, - In addition to (RCOO), it is preferable to avoid containing polar functional groups such as hydroxyl and epoxy groups. This improves hydrophobicity. m When M represents the general formula for saturated higher fatty acid salts, at least part or all of the saturated higher aliphatic group R is preferably composed of C. n-1 H 2n-1 - indicates an acyclic alkyl group, preferably composed of CH3(CH2). n-2 - indicates a straight-chain alkyl group. As a branched alkyl group, it is preferable that the branch is located away from the carboxylic acid ion group; for example, (CH3)2CH(CH2) can be cited. n-4 -etc. Preferably, it includes the formula (Cn-1 H 2n-1 COO) m M represents a noncyclic compound, more preferably comprising compounds of the general formula [CH3(CH2)]. n-2 COO] m M represents straight-chain compounds. In these general formulas, n represents the number of carbon atoms, and M represents a metal.

[0036] When the metal M in the saturated higher fatty acid salt is polyvalent, that is, when m is 2 or more, the number of carbon atoms n of the m saturated higher fatty acids can be the same or different. When the number of carbon atoms n of the m carbon acids is different from each other, the difference between the largest and smallest number of carbon atoms is preferably 4 or less, more preferably 2 or less. In order to form a more uniform hydrophobic surface at the molecular ends of the saturated higher fatty acid salt, it is preferable that the number of carbon atoms of each saturated higher fatty acid constituting the saturated higher fatty acid salt is the same.

[0037] <Nuclear Particles>

[0038] The nuclear particles are spherical with a sphericity of 0.80 to 1.00. A more preferred sphericity is 0.90 to 1.00. The saturated higher fatty acid salts of the nuclear particles act as lubricants, allowing for easy and unrestricted rolling. If the sphericity of the nuclear particles is above the lower limit, the particles easily roll and slide without resistance. For example, when applying a composition containing soap composite particles to the skin using the fingertips, the particles easily roll, thus providing a good effect on the skin. The theoretical maximum sphericity is 1, which is the case where the particle image is perfectly circular.

[0039] Circularity can be used to analyze particle images, measure the area A and perimeter C of the particle image, and define the diameter (equivalent diameter of a circle) of the circle with the same area A as the particle image as D, and π as the value of pi, and calculate it using the following formula.

[0040] (Circularity) = πD / C

[0041] As a method for determining particle sphericity, a flow-type particle image analysis device can be used, for example, to determine particle shape, particle size distribution, and particle number by resolving two-dimensional images of a particle swarm. Alternatively, an electron microscope can be used to observe the particle surface from multiple fields of view, perform three-dimensional image analysis, and thereby calculate the sphericity.

[0042] In the soap composite particles of this embodiment, the total content of Li₂O, Na₂O, Al₂O₃, MgO, CaO, ZnO, BaO, TiO₂, SiO₂, Fe₃O₄, Fe₂O₃, and FeO in the core particles is 0 to 15% by mass. These metal oxides (hereinafter, sometimes referred to as "specific metal oxides") sometimes originate from inorganic oxides added externally to the core particles, sometimes from inorganic oxides added internally to the core particles, and sometimes from saturated higher fatty acid salts. The specific metal oxides may also differ from the inorganic oxides added externally to the core particles and sometimes from the inorganic oxides added internally to the core particles.

[0043] When the nuclei do not contain a specific metal oxide, it is preferable not to add inorganic oxides to the nuclei, or to add inorganic oxides that are different from the specific metal oxides. In this case, the content (total content) of the specific metal oxides in the nuclei can be 0% by weight, but there may also be cases where the specific metal oxides are mixed into the nuclei as impurities, or where a portion of the inorganic oxides added to the nuclei are included in the nuclei.

[0044] When the nucleus contains a specific metal oxide, the inorganic oxide added to the nucleus preferably includes the specific metal oxide. In this case, the content (total content) of the specific metal oxide in the nucleus is preferably 0.01% by weight or more.

[0045] The specific metal oxides are Al2O3, MgO, ZnO, TiO2, SiO2, Fe3O4, Fe2O3, and FeO. When these are also preferably added externally or internally to the nucleus particles as functional inorganic oxides, their content is preferably 0.01% by weight or more. This enhances the functionality of the inorganic oxide and continuously improves its performance.

[0046] The metals (Li, Na, Al, Mg, Ca, Zn, Ba, Ti, Si, Fe) contained in the specific metal oxide can also be the same as the metals that form saturated higher fatty acid salts (preferably Li, Na, Al, Mg, Ca, Zn, Ba). By keeping the content of the specific metal oxide in the nucleus below the aforementioned upper limit, the crystallinity of the saturated higher fatty acid salt is easily maintained. This makes it easier to maintain the shape of the nucleus, improving the skin feel. Different metals can be selected when the metals contained in the specific metal oxide and the metals that form the saturated higher fatty acid salt are respectively chosen from the group consisting of Li, Na, Al, Mg, Ca, Zn, Ba.

[0047] The median particle size of the nuclear particles is preferably greater than 3 μm and less than 20 μm, more preferably greater than 5 μm and less than 15 μm, and even more preferably greater than 7 μm and less than 10 μm. If the median particle size of the nuclear particles exceeds the lower limit, the cohesive force of the particles decreases, making it difficult to form lumps. If the median particle size of the nuclear particles is less than the upper limit, the surface area per unit weight increases, the exposed area of ​​the inorganic oxide increases, and the sustainability of the inorganic oxide's function improves.

[0048] In applications of compositions containing the aforementioned soap composite particles to the skin, if the median particle size of the core particles exceeds the lower limit, they spread easily on the skin, resulting in a uniform skin feel relative to evenness of application. Furthermore, if the median particle size of the core particles is smaller than the upper limit, the roughness caused by particle size is less noticeable with the fingertips, improving the skin feel.

[0049] <Inorganic Oxides>

[0050] The soap composite particles of the embodiment have an inorganic oxide externally added to the core particles. As mentioned above, the core particles are not particularly limited as long as they contain a structure of saturated higher fatty acid salts, but inorganic oxides can also be added internally to the core particles. The inorganic oxide internally added to the core particles can also be embedded within the core particles. The inorganic oxide externally added to the core particles preferably covers at least a portion of the outer surface of the core particles.

[0051] Examples of inorganic oxides include metal oxides, metal nitrides, silicates, sulfates, carbonates, phosphates, and other inorganic particles. Specific examples of inorganic oxides include any one or more of zinc oxide, magnesium oxide, titanium dioxide, mica, talc, kaolin, sericite, silicon dioxide, iron oxide, aluminum oxide, zirconium oxide, and zeolite.

[0052] The inorganic oxide particles are preferably functional particles. As a function, it is preferred that the inorganic oxide particles, when used as soap composite particles, act together with saturated higher fatty acid salts on the target material. Specific examples of the function are not particularly limited, but can include ultraviolet reflectivity, sun protection, opacity as a pigment, anti-inflammatory properties, X-ray absorption, solid lubrication, mold release properties, antibacterial properties, and electrical insulation.

[0053] The content of inorganic oxides in the soap composite particles (the sum of internal and external additions) is preferably 3-80% by weight. If the sum is above the lower limit, the exposed area of ​​the inorganic oxides increases, and the sustainability of the inorganic oxides' function improves. If the sum is below the upper limit, the combination of saturated higher fatty acid salts and inorganic oxides is stable, and the uniformity of the soap composite particles improves.

[0054] The content (internal addition amount) of inorganic oxides in the nuclei is preferably 5-75% by weight, more preferably 5-10% by weight. If the internal addition amount is above the lower limit, the exposed area of ​​the inorganic oxides increases, and the sustainability of the inorganic oxides' function is improved. If the internal addition amount is below the upper limit, the mixing of saturated higher fatty acid salts and inorganic oxides becomes easier, and the uniformity of the nuclei is improved.

[0055] The amount of inorganic oxide added relative to 100 parts by weight of the nucleus particles is preferably 0.01 to 15 parts by weight, more preferably 0.05 to 8.0 parts by weight. If the amount added is above the lower limit, the amount of inorganic oxide present on the surface of the nucleus particles increases, and the sustainability of the function of the inorganic oxide is improved. If the amount added is below the upper limit, the lubricity and tactile feel characteristic of saturated higher fatty acid salts become more superior.

[0056] The inorganic oxide added externally to the nucleus can be the same type of inorganic oxide as the inorganic oxide added internally to the nucleus, or it can be a different inorganic oxide. The inorganic oxide added internally to the nucleus can be one type or two or more types. When two or more inorganic oxides are added internally to the nucleus, the amount added internally can also be the combined amount of the two or more types. The inorganic oxide added externally to the nucleus can be one type or two or more types. When two or more inorganic oxides are added externally to the nucleus, the amount added externally can also be the combined amount of the two or more types.

[0057] Inorganic oxides added to the core particles can also function as flow-improving agents. In this case, the flow-improving agent acts as a bearing, increasing the flowability of the soap composite particles and improving the skin feel. The inorganic oxides added to the core particles can also be used as both flow-improving agents and particles with other functions.

[0058] Externally added and / or internally added inorganic oxides to the nuclei can also be used for coating treatment, such as hydrophobication treatment. Hydrophobication treatment is not particularly limited and can include any of the following: silane coupling treatment, silicone oil treatment, long-chain alkylsilane treatment, fatty acid salt treatment, long-chain alkane treatment, long-chain olefin treatment, and long-chain alkyne treatment. Modified silicone oil can also be used in silicone oil treatment.

[0059] In the case of silane coupling treatment or silicone oil treatment, siloxane bonds are formed and immobilized on the surface of inorganic oxides through hydrolysis and dehydration condensation reactions of the silane coupling agent or silicone oil, thereby hydrophobizing the inorganic oxides. Therefore, the inorganic oxides exhibit high dispersibility even when kneaded into soaps composed of hydrophobic higher saturated fatty acid salts at high temperatures.

[0060] In the case of fatty acid salt treatment, the composition of the fatty acid salt is the same as or similar to that of the higher saturated fatty acid salts used in soap making. Therefore, the inorganic oxides that have been surface-treated with fatty acid salts have high dispersibility and high adhesion to the soap. In addition, if the fatty acid salt used in the fatty acid salt treatment is equivalent to the aforementioned higher saturated fatty acid salt, the mass of that portion can be removed from the mass of the inorganic oxides and added to the mass of the higher saturated fatty acid salts.

[0061] In the cases of long-chain alkylsilane treatment, long-chain alkane treatment, long-chain olefin treatment, and long-chain alkyne treatment, inorganic oxides can be hydrophobized by using long-chain aliphatic compounds corresponding to each treatment. The chain length of these long-chain aliphatic compounds is not particularly limited; for example, it can be 8 to 30 carbon atoms.

[0062] The average primary particle size of the inorganic oxides added externally and / or internally to the core particles is preferably 0.01 to 1.0 μm. When the average primary particle size of the inorganic oxide is above or above the lower limit, the particles of the inorganic oxide are difficult to aggregate and easy to disperse. In particular, if such inorganic oxides are added externally, the skin feel of the soap composite particles becomes better. When the average primary particle size of the inorganic oxide is below the upper limit, the inorganic oxide is easy to be internally added to the core particles, and it is difficult to detach from the soap composite particles when added externally. In particular, if such inorganic oxides are added externally, the particulate nature of the inorganic oxides (surface roughness caused by particles) is reduced, and the skin feel of the soap composite particles becomes better.

[0063] <Method for Manufacturing Soap Complex Particles>

[0064] The soap composite particles of this embodiment can be manufactured, for example, through a pulverizing process of saturated higher fatty acid salts, an external addition process of inorganic oxides to the core particles, and a spheroidizing process of the core particles. The spheroidizing process can be performed before or after the external addition process.

[0065] The manufacturing method preferably includes, where a spheroidizing process is performed before the external addition process: a pulverizing process for pulverizing solid material of saturated higher fatty acid salts; a spheroidizing process for spheroidizing particles obtained in the pulverizing process; and an external addition process for externally adding inorganic oxides to the nuclei obtained in the spheroidizing process.

[0066] The manufacturing method wherein a spheroidizing process is performed after the external addition process preferably includes: a pulverizing process for pulverizing solid material of saturated higher fatty acid salts; an external addition process for externally adding inorganic oxides to particles obtained in the pulverizing process; and a spheroidizing process for spheroidizing particles obtained in the external addition process.

[0067] When inorganic oxides are added to the nuclei, it is preferable to have a kneading step before the pulverizing step, in which the mixed powder obtained by mixing saturated higher fatty acid salts and inorganic oxides is melted and kneaded. When inorganic oxides are not added to the nuclei, it is preferable to heat and melt the saturated higher fatty acid salts to obtain a solid substance of saturated higher fatty acid salts.

[0068] When inorganic oxides are added to the nuclei, the process can include: a metering step, which separately measures the saturated higher fatty acid salts and inorganic oxides used in the production of the nuclei; and a mixing step, which stirs and mixes the metered saturated higher fatty acid salts and inorganic oxides. The mixing of the particles is not particularly limited, and mixing devices such as double-cone mixers, V-type mixers, cylindrical mixers, high-speed mixers, Henschel mixers, and Nottingham mixers can be used.

[0069] While a portion of the raw materials can be mixed during the kneading process, it is preferable to pre-mix at least a portion of the raw materials before the kneading process. Pre-mixing allows for better control over the composition, particle size, and shape of saturated higher fatty acid salts and inorganic oxides.

[0070] The kneading process is preferably carried out under conditions where the saturated higher fatty acid salts are melted or softened by heating. This allows the inorganic oxides, after being mixed with the saturated higher fatty acid salts, to be added to the mixture. Both batch and continuous kneading machines can be used. There are no particular limitations on the kneading machine; examples include open mills, kneaders, pressure kneaders, Banbury mixers, single-screw extruders, and twin-screw extruders. The heating temperature in the kneading process can be appropriately set according to the melting point of the saturated higher fatty acid salts; for example, approximately 80–250°C, 100–200°C, or 100–140°C are possible.

[0071] If a kneading process of saturated higher fatty acid salts and inorganic oxides or a melting process of saturated higher fatty acid salts are performed before the pulverizing process, a cooling process is preferably implemented to cool the mixture obtained in the kneading process or the melt obtained in the melting process. Alternatively, the molten mixture or melt can be passed through a cooling roller or similar device, allowing cooling components in contact with the mixture or melt to absorb residual heat. Cooling components such as cooling rollers may also contain a refrigerant such as cooling water. During the cooling process, heat can also be dissipated from the mixture through air cooling, forced airflow, or other methods.

[0072] The grinding process can also be implemented in multiple stages, such as coarse grinding and fine grinding. There are no particular limitations on the equipment used for coarse grinding of particles; crushers, hammer mills, mesh-type feather mills, and milling mills can be used. There are also no particular limitations on the equipment used for fine grinding of particles; jet mills, reverse jet mills, and high-speed rotary mills can be used.

[0073] When pulverizing the solid material to the desired particle size, the particle size can also be adjusted through a classification process as needed. In the classification process, for example, an Elbow-Jet Air Classifier (using inertial classification), a Mikroplex Classifier (using centrifugal classification), or an airflow classifier can be used. Particles larger than the desired particle size can be returned to the pulverizing process for further pulverization. Particles smaller than the desired particle size can also be returned to the mixing or melting process for reuse, depending on the composition.

[0074] The spheroidizing process is a process of spheroidizing particles by heating. There are no particular limitations on the spheroidizing apparatus; examples include apparatuses that mechanically adjust particle shape, such as impact spheroidizing apparatuses; apparatuses that adjust particle shape by dissolving and desolventizing binders, such as spray drying apparatuses; and apparatuses that adjust particle shape by heating in a medium or using hot air. When the spheroidizing process is performed before the external addition process, spherical core particles are obtained. When the spheroidizing process is performed after the external addition process, soap composite particles with spherical core particles are obtained. A grading process may also be performed after the spheroidizing process, if necessary.

[0075] The external addition process involves adding inorganic oxides to the nuclei by mixing them with the nuclei. In this process, mixing devices such as high-speed mixers and Henschel mixers, as well as powder processing devices such as mechanical mills, can be used.

[0076] <Soap Complex Particles>

[0077] In addition to the functions of saturated higher fatty acid salts, the soap composite particles of the embodiments also possess functionality based on internally or externally added inorganic oxides, thus enabling their use as various functional materials. The applications of the soap composite particles are not particularly limited; for example, they can be used as touch improvers, lubricants, release agents, anti-caking agents, cosmetic raw materials, coloring materials, processing aids, dispersants, and additives.

[0078] <Analytical Methods for Soap Complex Particles>

[0079] As described above, the soap composite particles of the embodiment have core particles containing saturated higher fatty acid salts and inorganic oxides added externally to the core particles. Since the core particles are mainly composed of saturated higher fatty acid salts, the saturated higher fatty acid salts and inorganic oxides can be separated. Therefore, even if the inorganic oxides internally added to the core particles and the inorganic oxides externally added to the core particles are the same substances, the amount of internal addition and external addition can be evaluated.

[0080] As a specific example of a method for separating nuclear particles from external additives (externally added inorganic oxides), one method involves inserting a probe of an ultrasonic homogenizer into a dispersion obtained by adding pre-weighed powdered soap composite particles to a dispersion medium and irradiating it with ultrasonic waves. This allows the external additives detached from the nuclear particles to remain suspended in the dispersion medium. After allowing the nuclear particles to settle through standing, centrifugation, or other means, the supernatant containing the suspended external additives can be extracted and separated through liquid-liquid separation.

[0081] To suppress powder aggregation, the dispersion medium is preferably an aqueous solution prepared by dissolving a surfactant in water. Since saturated higher fatty acid salts are insoluble in water, the added inorganic oxides can maintain the state contained within the nuclei.

[0082] The amount of nuclear particles separated from the additive material can be determined by repeatedly washing and filtering the precipitate with solvent using filter paper capable of trapping nuclear particles, followed by drying the precipitate and weighing it. Regarding the trapping performance of the filter paper, it is preferable to retain particles larger than 1 μm. The amount of additive material can also be calculated by subtracting the mass of the nuclear particles obtained from the weighing from the mass of the soap composite particles.

[0083] The composition and properties of the additives contained in the supernatant can be analyzed, for example, by X-ray fluorescence (XRF) analysis of the supernatant.

[0084] The composition and structure of inorganic oxides added to nuclear particles can be analyzed, for example, by fluorescence X-ray spectroscopy (XRF) analysis of nuclear particles obtained as sediments.

[0085] <Cosmetics containing soap complex particles>

[0086] The cosmetic product of this embodiment includes the aforementioned soap complex particles. Examples of cosmetic products containing soap complex particles include color cosmetics such as foundation, liquid foundation, eyeshadow, blush, white face powder, concealer, blush, eyebrow powder, and highlighter; cleansing agents such as makeup remover and facial cleanser; skin care cosmetics such as massage cream, moisturizer, and lotion; body care cosmetics such as bath products, sunscreen, and deodorant spray; basic cosmetics such as base makeup; and hair care cosmetics such as shampoo, conditioner, hair serum, and hair dye. These cosmetics can be prepared by mixing and processing various raw materials in proportions suitable for their intended use.

[0087] The soap complex particles may be included in the cosmetic product in a range of 0.5% to 60% by mass relative to the total amount of the cosmetic product. Preferably, the soap complex particles may be included in a range of 1% to 40% by mass relative to the total amount of the cosmetic product, and more preferably, 2% to 30% by mass. This is because if the content of soap complex particles is less than 0.5% by mass, it is difficult to perceive an improvement in the skin feel when using the cosmetic product. Furthermore, if it exceeds 60% by mass, it is impossible to expect an effect commensurate with the amount used, and it is also easy to cause problems in maintaining the quality and stability of the cosmetic product.

[0088] In addition to the soap complex particles, various conventionally used ingredients can be incorporated into the cosmetic. Examples include pigments, surface-treated pigments, ultraviolet absorbers, physiologically active ingredients, oils, surfactants, fluorinated compounds, resins, adhesives, preservatives, fragrances, moisturizers, salts, solvents, antioxidants, chelating agents, neutralizing agents, pH adjusters, and insect repellents. These ingredients can be incorporated in amounts that do not impair the effectiveness of the cosmetic of the present invention.

[0089] The cosmetic may also contain paraffin-based solvents such as isododecane. Because the surface of the core particles in the soap composite particles is hydrophobic, the inorganic oxide particles are difficult to detach, resulting in excellent persistence of the metal soap particles' function. Furthermore, if the surface of the inorganic oxide is hydrophobically treated, the affinity of the inorganic oxide for the surface of the core particles becomes even higher, further inhibiting the detachment of the inorganic oxide particles.

[0090] The present invention has been described above based on preferred embodiments, but the present invention is not limited to the above embodiments and various changes can be made without departing from the spirit of the present invention.

[0091] Example

[0092] The following describes embodiments of the present invention, but the present invention is not limited to these embodiments.

[0093] <Manufacturing of Soap Complex Particles>

[0094] Soap composite particles, in which inorganic oxides are added to the nuclei containing saturated higher fatty acid salts and inorganic oxides, were manufactured by performing the following processes.

[0095] (Mixed process)

[0096] As shown in Tables 1-4, “Saturated higher fatty acid salts” and “Added inorganic oxides”, saturated higher fatty acid salts and inorganic oxides were measured and added to a 20L Henschel mixer (FM20 manufactured by Coke Industries, Ltd., Japan), and stirred to obtain a mixed powder.

[0097] (Kneading process)

[0098] The mixed powder obtained in the mixing process is heated to 100-140°C using a twin-screw mixer (PCM-30 manufactured by Ikegai Co., Ltd.) for melt mixing. The molten mixture discharged from the mixer is then passed through cooled rolling rollers to obtain a plate-shaped solid mixture.

[0099] (Grinding process)

[0100] The plate-shaped solid mixture obtained in the mixing process is coarsely pulverized using a hammer mill to obtain coarsely pulverized material with a particle size of 0.5–3.0 mm. The coarsely pulverized material is then finely pulverized using a jet mill (ULTRA SONIC JETMILL I-2 manufactured by Pneumatic Industries, Ltd., Japan) to obtain finely pulverized material with an average particle size of 3–20 μm on a volume basis.

[0101] (Grading process)

[0102] The finely pulverized material obtained in the pulverization process is used to remove particles smaller than 3μm using an air classifier (DS2UR manufactured by Pneumatic Industries, Ltd., Japan).

[0103] (Spheroidization process)

[0104] The graded powder obtained in the grading process is stirred for 20 minutes in a jacketed Henschel mixer (10L, Coke FM10, Japan) with warm water flowing at 60-90°C to achieve spheroidization.

[0105] (External additive process)

[0106] For the spherical nuclei obtained in the spheroidizing process, as shown in Tables 1-4 under "External Addition of Inorganic Oxides", external addition of inorganic oxides yields soap composite particles.

[0107] <Nuclear Particle Structure>

[0108] The spherical nuclei obtained in the spheroidization process were used as samples, and their structure was measured using the following method. Alternatively, the same analytical method for soap composite particles described above can be used to use nuclei separated from external additives as samples.

[0109] (Circularity)

[0110] The roundness of the nuclear particles was determined using a flow particle image analysis device.

[0111] (Volume-based median particle size)

[0112] Using a Coulter counter, the volume distribution is determined by measuring the electrical changes as nuclear particles pass through an aperture tube, and the median particle size (D50) is calculated from this.

[0113] <Methods for evaluating skin feel>

[0114] A spoonful of soap compound powder was placed on the wrist of one arm using an ear pick. The powder was then gently rolled on the skin with the middle finger of the opposite hand, tracing a 4cm diameter circle for 15 seconds. The tactile sensation was evaluated using the middle finger and wrist. A four-member evaluation panel (two adult men and two adult women) categorized the user experience into various items, assigning scores to each item for sensory evaluation. The evaluation items and criteria are described below.

[0115] (Evaluation items for skin feel)

[0116] Evenness of application... Whether the powder is evenly applied to the skin when applying the powder.

[0117] Adhesion... Whether the powder fills the pores well when it is applied.

[0118] Dryness... How well does the skin feel after applying the powder?

[0119] Lightweight feel... When applying powder, is the weight felt light after application?

[0120] Makeup staying power... How well does the makeup last when rubbed off with your fingers after applying the powder?

[0121] Softness... When applying powder, whether the powder has good softness after application.

[0122] (Evaluation criteria for skin feel)

[0123] 5: Excellent.

[0124] 4: Excellent.

[0125] 3: Normal.

[0126] 2: Poor.

[0127] 1: Very bad.

[0128] <The Manifestation of Function>

[0129] Regarding the manifestation of the functions of inorganic oxides, the following evaluation criteria are used for each type of inorganic oxide.

[0130] (Evaluation criteria for the manifestation of function)

[0131] 5: It exhibits the functions of inorganic oxides.

[0132] 3: It exhibits the function of a small amount of inorganic oxides.

[0133] 1: The function of inorganic oxides is not apparent.

[0134] <Functional continuity>

[0135] 9.5g of the volatile organic solvent used in cosmetics was placed in a sample vial, followed by 0.5g of soap complex particle powder. The vial was capped, placed on a shaking table, and stirred. The vial was then allowed to stand for 24 hours at 20°C. Humidity was maintained within the range of normal humidity (45–85% RH). The shape of the particles was observed using an optical microscope to determine if there was any change in shape compared to before solvent impregnation. Functional persistence was evaluated according to the following criteria.

[0136] (Evaluation criteria for functional sustainability)

[0137] 5: The shape of the soap compound particles remained completely unchanged.

[0138] 3: The shape of the soap complex particles has changed to some extent.

[0139] 1: The shape of the soap complex particles has changed.

[0140] <Overall Evaluation>

[0141] The comprehensive evaluation is based on the total score obtained from three items: (1) skin feel, (2) manifestation of function, and (3) persistence of function, and is evaluated according to the following evaluation criteria.

[0142] (Evaluation criteria for comprehensive evaluation)

[0143] +++: The total score is 15.

[0144] ++: The total score is 13 or 14.

[0145] +: The total score is 11 or 12.

[0146] -: Total score is less than 11.

[0147] <Evaluation Results>

[0148] The evaluation results are shown in Tables 1–4. In the “Saturated Higher Fatty Acid Salts” column, fatty acid salts are represented by a combination of the fatty acid name and the metal element symbol, for example, by using “Stearic Acid Ca” to represent “Calcium Stearate”. Unsaturated fatty acid salts are used in some of the comparative examples.

[0149] 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. In addition, oleic acid (18 carbon atoms, 1 double bond) and linoleic acid (18 carbon atoms, 2 double bonds) are straight-chain unsaturated fatty acids.

[0150] The weight parts in Tables 1-4 are set to a total of 100 parts by weight for the internal addition of saturated higher fatty acid salts and inorganic oxides. Therefore, the value of the internal addition of inorganic oxides (parts by weight) is equal to the value of the content of inorganic oxides in the nuclei (%).

[0151] In the "Hydrophobication Treatment" column of Tables 1-4, "None" is indicated when inorganic oxides are not hydrophobically treated, "SiCp" is indicated when silane coupling treatment is performed, and "SiOi" is indicated when silicone oil treatment is performed.

[0152] [Table 1]

[0153] [Table 2]

[0154] [Table 3]

[0155] [Table 4]

[0156] In Examples 1 to 26, the overall evaluation was +++, ++ or +, which can achieve both the improvement of skin feel and the sustainability of the function of soap complex particles.

[0157] In Comparative Examples 1-4, the overall evaluation is -.

[0158] The specific metal oxide content in the nuclear particles of Comparative Example 1 exceeded 10% by mass, and the functional persistence was 1.

[0159] Comparative Example 2 has a roundness of less than 0.80 and a functional continuity of 1.

[0160] Comparative Examples 3 and 4 used unsaturated fatty acid salts instead of saturated higher fatty acid salts, but the skin feel was rated poorly.

[0161] Industrial applicability

[0162] The soap composite particles of this invention can achieve both improved skin feel and sustained functionality of inorganic oxides, and can be used in the manufacture of cosmetics.

Claims

1. A soap composite particle comprising a core particle containing a saturated higher fatty acid salt and an inorganic oxide added to said core particle, characterized in that, The total content of Li₂O, Na₂O, Al₂O₃, MgO, CaO, ZnO, BaO, TiO₂, SiO₂, Fe₃O₄, Fe₂O₃, and FeO in the nuclear particles is 0% to 15% by mass. The nuclear particle is spherical with a sphericity of 0.80 to 1.

00.

2. The soap composite particles according to claim 1, characterized in that, The number of carbon atoms in the saturated higher fatty acid salt is in the range of 10 to 20.

3. The soap composite particles according to claim 1, characterized in that, The metal that forms 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, characterized in that, The amount of inorganic oxide added relative to 100 parts by weight of the nuclear particles is 0.01 to 15 parts by weight.

5. The soap composite particles according to claim 1, characterized in that, The inorganic oxide is any one or more of zinc oxide, magnesium oxide, titanium dioxide, mica, talc, kaolin, sericite, silicon dioxide, iron oxide, aluminum oxide, zirconium oxide, and zeolite.

6. The soap composite particles according to claim 1, characterized in that, The inorganic oxide is hydrophobically treated.

7. The soap composite particles according to claim 6, characterized in that, The hydrophobication treatment is any one of the following: silane coupling treatment, silicone oil treatment, long-chain alkylsilane treatment, fatty acid salt treatment, long-chain alkane treatment, long-chain olefin treatment, and long-chain alkyne treatment.

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

9. The soap composite particles according to claim 1, characterized in that, The median particle size of the nuclear particles in the volume reference range exceeds 3 μm and is less than 20 μm.

10. A method for manufacturing soap composite particles, as described in claim 1, characterized in that it comprises: The pulverizing process pulverizes solid substances containing saturated higher fatty acid salts; The spheroidizing process spheroidizes the particles obtained in the pulverizing process; and The external addition process involves adding inorganic oxides to the nuclear particles obtained in the spheroidization process.

11. A method for manufacturing soap composite particles, as described in claim 1, characterized in that it comprises: The pulverizing process pulverizes solid substances containing saturated higher fatty acid salts; An external addition process involves adding inorganic oxides to the particles obtained in the pulverizing process; and The spheroidizing process involves spheroidizing the particles obtained in the external addition process.

12. A cosmetic product, characterized in that, The cosmetic product contains soap complex particles as described in any one of claims 1 to 9.

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