cosmetics

Abstract

The present invention relates to a cosmetic comprising fatty acid magnesium salt particles and titanium oxide particulates. In the fatty acid magnesium salt particles, the fatty acid contains from 12 to 22 carbon atoms, the aspect ratio expressed by the following equation (1) is from 1.0 to 2.0, and the average thickness is from 250 to 600 nm.　Equation (1): Aspect ratio = major axis diameter of particle (µm) / minor axis diameter of particle (µm).

Description

[Technical Field]

[0001] The present invention relates to a cosmetic preparation containing a magnesium fatty acid. [Background technology]

[0002] Among cosmetics, powder cosmetics are required to have a moist feeling, as they are likely to be associated with images of being powdery, dry, and rough, and furthermore, among powder cosmetics, cosmetics used for finishing, such as loose powder, are required to have usability such as transparency and gloss rather than covering power. Patent Document 1 describes a powdered cosmetic containing a metal soap, and Patent Document 2 describes that by using a specific amount of metal soap microparticles having a specific particle size, a solid powdered cosmetic having excellent moldability, impact resistance, durability, etc. can be obtained. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-305935 [Patent Document 2] Japanese Patent Publication No. 2000-169342 Summary of the Invention [Problem to be solved by the invention]

[0004] As described in Patent Document 1, metal soaps are usually blended to increase impact resistance, and it has been common to blend them to increase impact resistance rather than to improve usability. Therefore, if the blending amount is too high, there is a risk that it will be difficult to remove or will have an adverse effect on usability, such as a squeaky feeling. Furthermore, the powder cosmetic described in Patent Document 2 leaves room for improvement in terms of usability. The present invention aims to provide a cosmetic product that is excellent in usability, such as moist feeling, transparency, and gloss. [Means for solving the problem]

[0005] As a result of intensive research to solve the above problems, the present inventors have found that a cosmetic preparation with excellent usability can be obtained by containing fatty acid magnesium salt particles having an aspect ratio within a specific range and fine titanium oxide particles. That is, the present invention relates to the following cosmetics. [1] A cosmetic comprising fatty acid magnesium salt particles and fine titanium dioxide particles, The fatty acid of the fatty acid magnesium salt particles is 12 to 22, The fatty acid magnesium salt particles have an aspect ratio represented by the following formula (1) of 1.0 or more and 2.0 or less, The cosmetic preparation, wherein the fatty acid magnesium salt particles have an average thickness of 250 to 600 nm. Aspect ratio = particle major axis diameter (μm) / particle minor axis diameter (μm) Equation (1) [2] The cosmetic preparation according to [1], further comprising an oily component. [3] The cosmetic preparation according to [1] or [2], wherein the content of the fine particle titanium dioxide is 10% by mass or less. [4] The cosmetic preparation according to [2] or [3], wherein the oil component comprises a liquid oil component. [5] The cosmetic preparation according to any one of [2] to [4], wherein the content of the oily component is 10% by mass or less. [6] The cosmetic according to any one of [1] to [5], wherein the cosmetic is a powder cosmetic. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a cosmetic preparation that is excellent in usability, such as moist feeling, transparency, and gloss. DETAILED DESCRIPTION OF THE INVENTION

[0007] The cosmetic of the present invention contains specific fatty acid magnesium salt particles as a metal soap. The fatty acid magnesium salt particles of the present invention are composed of a divalent fatty acid magnesium salt having 12 to 22 carbon atoms. Such particles can be prepared by a metathesis method in which a fatty acid alkali compound salt obtained by reacting a fatty acid having 12 to 22 carbon atoms with a monovalent alkali compound is reacted with a divalent magnesium salt in an aqueous solution.

[0008] The fatty acid used as the raw material for the fatty acid alkali compound salt is not particularly limited as long as it has 12 to 22 carbon atoms. That is, it may be either a naturally occurring fatty acid or a synthetic fatty acid, either a saturated fatty acid or an unsaturated fatty acid, and either a straight-chain or branched fatty acid. Furthermore, the fatty acid structure may contain functional groups such as a hydroxyl group, an aldehyde group, or an epoxy group. As the fatty acid, a straight-chain saturated fatty acid is preferred.

[0009] Furthermore, a fatty acid having 12 or more carbon atoms can impart excellent usability to cosmetics. On the other hand, a fatty acid having 22 or less carbon atoms can be easily obtained industrially as a fatty acid, and the solubility of the resulting fatty acid alkali compound salt in water does not decrease significantly, resulting in high productivity. The number of carbon atoms in the fatty acid is preferably 12 to 18, and more preferably 14 (i.e., the fatty acid magnesium is magnesium myristate).

[0010] Examples of fatty acids include lauric acid, myristic acid, myristoleic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, arachic acid, behenic acid, erucic acid, hydroxystearic acid, and epoxystearic acid, among which myristic acid is preferred. When mixed fatty acids are used, the myristic acid content in the fatty acids is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more.

[0011] The fatty acid magnesium salt particles of the present invention have an aspect ratio of 1.0 or more and 2.0 or less, preferably 1.0 or more and 1.6 or less, and more preferably 1.0 or more and 1.5 or less. In the present invention, the aspect ratio of a particle corresponds to the following formula (1), that is, the value obtained by dividing the major axis diameter of a fatty acid magnesium salt particle by the minor axis diameter (=major axis diameter / minor axis diameter). Aspect ratio = particle major axis diameter (μm) / particle minor axis diameter (μm) Equation (1) The closer the aspect ratio is to 1.0, the closer the particle shape is to a square or a circle. The fatty acid magnesium salt particles of the present invention preferably have a shape that is close to a square. This improves the spreadability on the skin and makes it easy to use.

[0012] The "major axis diameter" of a particle is the length of the particle's major axis, and more specifically, corresponds to the width of the particle at the maximum distance between two parallel lines sandwiching the particle. The "minor axis diameter" of a particle is the length of the particle's minor axis, and more specifically, corresponds to the width of the particle measured along a straight line passing through the midpoint of the major axis and perpendicular to the major axis. The average particle thickness is the average value obtained by measuring the side lengths of 10 fatty acid magnesium salt particles, with the largest surface facing forward. The average particle thickness is a value measured based on a two-dimensional projection image of the particle (more specifically, an SEM photograph).

[0013] Furthermore, the fatty acid magnesium salt particles of the present invention have an average particle thickness of 250 to 600 nm. Such a thickness allows the particles to be easily dissolved even under mild mixing conditions (production method) in cosmetics, facilitating uniform application to the skin as a cosmetic, and improving the feel after application. Furthermore, when the average thickness is 250 nm or more, the fatty acid magnesium salt particles are easy to handle when added to cosmetics, and there is no risk of a decrease in workability. The average particle thickness is more preferably 280 to 450 nm, and particularly preferably 300 to 450 nm. If the average particle thickness is 300 to 450 nm, the effects of the present invention can be obtained even more stably.

[0014] The cosmetic of the present invention, which uses a combination of fatty acid magnesium salt particles having the above-described specific properties and titanium dioxide particles, is excellent in usability, such as moist feeling, transparency, and gloss. It also achieves a natural glossy finish that differs from the gloss achieved by oil or glitter powder. This is presumably because the fatty acid magnesium salt particles of the present invention have a specific aspect ratio, which improves their spreadability on the skin.

[0015] Furthermore, the fatty acid magnesium salt particles of the present invention preferably have a particle index of 1.5 or more and 8.0 or less. Such a particle index makes it easier to apply the cosmetic product uniformly to the skin and allows the post-application feel to be maintained for a long period of time. Furthermore, a particle index of 1.5 or more ensures good dispersibility of the fatty acid magnesium salt particles when added to a cosmetic product, eliminating the risk of reduced workability. The particle index of the particles is preferably 1.5 or more and 6.0 or less, and more preferably 2.0 or more and 5.0 or less. When the particle index is 2.0 or more and 5.0 or less, the effects of the present invention can be obtained even more stably. In the present invention, the particle index of a particle corresponds to the following formula (2), i.e., the value obtained by dividing the major axis diameter of a fatty acid magnesium salt particle by the minor axis diameter (= major axis diameter / minor axis diameter) by the average thickness of the particle [= (major axis diameter / minor axis diameter) / average thickness of the particle]. Particle index = [(major axis diameter of particle (μm) / minor axis diameter of particle (μm)) / average particle thickness (nm)] × 1000 Equation (2)

[0016] Furthermore, the fatty acid magnesium salt particles of the present invention have a narrow particle size distribution, which allows them to be uniformly present in a cosmetic, making it easier to more stably achieve the effects of the present invention (particularly, improving the feel of the cosmetic). Specifically, the fatty acid magnesium salt particles preferably have a median diameter of 10.0 to 40.0 μm, and a particle size summary value A represented by the following formula (3) is preferably 2.5 or less. Grain size summary value A = (D90 - D10) / D50 Equation (3) (However, 10.0≦D50≦40.0) D10: 10% cumulative diameter (μm) of fatty acid magnesium salt particles on a volume basis D50: Volume-based median diameter of fatty acid magnesium salt particles (μm) D90: 90% cumulative diameter (μm) of fatty acid magnesium salt particles on a volume basis

[0017] In the present invention, the particle size summary value A is calculated from particle diameters measured by a microtrack laser diffraction method. When the particle size summary value A is 2.5 or less, the particle diameter of the fatty acid magnesium salt particles present in the cosmetic becomes uniform, the cosmetic has good dispersibility, productivity does not decrease, and a cosmetic having the desired feel can be produced. It is more preferable that the particle size summary value A satisfies the relationship 0.5≦A≦2.5. When the relationship 0.5≦A≦2.5 is satisfied, the effects of the present invention can be obtained even more stably. When the particle size summary value A is 0.5 or more, yield does not decrease and industrially stable production is possible. In the above formula (3), when the cumulative curve is calculated assuming the total volume of the powder mass to be 100%, the particle diameters at the 10%, 50%, and 90% points of the cumulative curve are defined as the 10% cumulative diameter (D10), 50% median diameter (D50; median diameter), and 90% cumulative diameter (D90) (μm), respectively. Note that particle diameter refers to the particle diameter of the primary particle. If the particles are aggregated during measurement, they are dispersed using ultrasound or the like before measurement.

[0018] The particle size summary value A can be adjusted by appropriately adjusting the concentration of the fatty acid alkali compound salt, the temperature during the reaction between the fatty acid alkali compound salt and the magnesium salt, and the dropping speed when the aqueous solution containing the magnesium salt is dropped into the aqueous solution containing the fatty acid alkali compound salt. Furthermore, for those with a wide particle size distribution, i.e., those with a large value of the particle size summary value A, this can be achieved in post-processing by classification using sieves such as 100 mesh, 200 mesh, and 330 mesh.

[0019] The microtrack laser diffraction method used here is a method for determining particle size distribution by utilizing scattered light obtained by irradiating particles with laser light. In the present invention, a wet measurement is performed in which a sample is introduced into a circulating organic solvent in which fatty acid magnesium salt particles are insoluble, such as ethanol or isopropyl alcohol. The particle diameters measured in the present invention are in the range of 0.1 μm to 200 μm, and the value expressed by the above formula (1) is taken as the particle size summary value A. In the present invention, the measurement can be performed using, for example, a Microtrack MT-3000 manufactured by Nikkiso Co., Ltd.

[0020] The fatty acid magnesium salt particles of the present invention preferably have a volume-based median diameter (D50) of 10.0 to 40.0 μm. Such a particle diameter provides a good feel when used. The median diameter of the fatty acid magnesium salt particles is preferably 13.0 to 35.0 μm, more preferably 15.0 to 25.0 μm. The particle diameter can be measured by a microtrack laser diffraction method in the same manner as the particle size summary value A described above.

[0021] The shape of the fatty acid magnesium salt particles of the present invention is not particularly limited, but from the viewpoint of usability, a plate shape is preferred.

[0022] To obtain fatty acid magnesium salt particles that satisfy the above-mentioned specific properties, they can be prepared by a metathesis method in which a fatty acid alkali compound salt obtained by reacting a monovalent alkali compound with a fatty acid having 12 to 22 carbon atoms is reacted with a divalent magnesium salt in an aqueous solution. When the magnesium salt-containing aqueous solution and the fatty acid alkali compound salt-containing aqueous solution that have been separately prepared by the metathesis reaction are mixed, it is preferable to gradually add the magnesium salt-containing aqueous solution to the fatty acid alkali compound salt-containing aqueous solution, as described below.

[0023] Examples of monovalent alkali compounds that can be used as raw materials for fatty acid alkali compound salts include hydroxides of alkali metals (sodium, potassium, etc.), and amines such as ammonia, monoethanolamine, diethanolamine, triethanolamine, etc. Hydroxides of alkali metals such as sodium and potassium are preferred because they have high solubility in water when converted into fatty acid alkali compound salts.

[0024] The fatty acid alkali compound salt used in the present invention is generally obtained by reacting a monovalent alkali compound with a fatty acid at a temperature that is equal to or higher than the melting point of the fatty acid but does not decompose the fatty acid, preferably 100°C or lower, more preferably 50 to 100°C, even more preferably 60 to 95°C, and particularly preferably 80 to 95°C.

[0025] The fatty acid magnesium salt particles of the present invention can be obtained, for example, by reacting the fatty acid alkali compound salt obtained above with a magnesium salt in an aqueous solution. Specifically, the magnesium salt is a salt of inorganic magnesium with an inorganic acid or an organic acid. Examples of magnesium salts include magnesium chloride, magnesium sulfate, and magnesium acetate. Magnesium chloride and magnesium sulfate are particularly preferred because they have high solubility in water and react efficiently with the fatty acid alkali compound salt.

[0026] The reaction of the fatty acid alkali compound salt with the divalent magnesium salt is specifically carried out by separately preparing an aqueous solution containing the magnesium salt and an aqueous solution containing the fatty acid alkali compound salt and then mixing them, for example, by adding the aqueous solution containing the magnesium salt to the aqueous solution containing the fatty acid alkali compound salt, or by adding both to separate reaction vessels.

[0027] When mixing the aqueous solution containing a fatty acid alkali compound salt with the aqueous solution containing a magnesium salt, for example, if the aqueous solution containing a magnesium salt is added all at once to the aqueous solution containing a fatty acid alkali compound salt, the resulting fatty acid magnesium salt particles may have a non-uniform shape and a large aspect ratio. Therefore, in the present invention, it is preferable to gradually add the aqueous solution containing a magnesium salt to the aqueous solution containing a fatty acid alkali compound salt at an appropriate speed.

[0028] The dropping rate is preferably 0.005 to 0.8 mol / min per unit time, more preferably 0.01 to 0.5 mol / min. Mixing at such a dropping rate allows the exchange reaction between alkali and magnesium to proceed gently, resulting in fatty acid magnesium salt particles with an appropriate aspect ratio and thickness. A rate of 0.005 mol / min or more allows fatty acid magnesium salt particles with the desired aspect ratio and thickness to be obtained. On the other hand, a dropping rate of 0.8 mol / min or less per unit time results in fatty acid magnesium salt particles with a uniform shape and the desired aspect ratio and thickness, resulting in good particle size consistency. The unit of "mol / min" for the magnesium salt to be added dropwise is the number of moles of magnesium salt to be added dropwise per unit time per mole of fatty acid alkali compound.

[0029] The concentration of the fatty acid alkali compound salt during the production of the fatty acid magnesium salt is typically 1% by mass to 20% by mass, preferably 5% by mass to 15% by mass, from the standpoint of the productivity of the fatty acid magnesium salt and the handleability of the fatty acid alkali compound salt-containing aqueous solution or the resulting fatty acid magnesium salt slurry. A fatty acid alkali compound salt concentration of 1% by mass or higher is preferred, as it provides good productivity of the fatty acid magnesium salt. A concentration of 20% by mass or lower prevents an increase in the viscosity of the fatty acid alkali compound salt-containing aqueous solution or the resulting fatty acid magnesium salt slurry, allowing for a uniform reaction. The concentration of the magnesium salt in the magnesium salt-containing liquid is typically 10% by mass to 50% by mass, preferably 10% by mass to 40% by mass, from the standpoint of the productivity of the fatty acid magnesium salt and the handleability of the fatty acid alkali compound salt-containing aqueous solution or the resulting fatty acid magnesium salt slurry.

[0030] The reaction of the fatty acid alkali compound salt with the magnesium salt is carried out under temperature conditions that are generally used by those skilled in the art, taking into consideration the solubility of the fatty acid alkali compound salt, preferably 50 to 100°C, more preferably 60 to 95°C. A reaction temperature of 50°C or higher ensures a good reaction rate between the fatty acid alkali compound salt and the magnesium salt.

[0031] In order to stabilize the fatty acid magnesium salt slurry during the reaction of the fatty acid alkali compound salt with the magnesium salt and thereby improve the productivity of the fatty acid magnesium salt, it is preferable to add a polyalkylene glycol ether, particularly a triblock ether having a structure (EO-PO-EO) in which an oxypropylene block is sandwiched between oxyethylene blocks. The content of the polyalkylene glycol ether in the fatty acid magnesium salt slurry is usually 0.01 to 5 parts by mass, preferably 0.05 to 2 parts by mass, per 100 parts by mass of the fatty acid alkali compound salt. The polyalkylene glycol ether may be added to the reaction system before the reaction of the monovalent alkali compound with the fatty acid, or may be added to the reaction system before the reaction of the fatty acid alkali compound with the magnesium salt.

[0032] This method yields a fatty acid magnesium salt cake with a reduced moisture content, which is separated using a dehydrator, filter press, etc. The fatty acid magnesium salt cake with a reduced moisture content is then dried using a rotary dryer, flash dryer, ventilated tray dryer, vacuum tray dryer, spray dryer, fluidized bed dryer, etc.

[0033] In the present invention, the fatty acid magnesium salt cake must be dried at (α-60)°C≦α≦(α-30)°C, where α°C is the water vaporization peak top temperature of the resulting fatty acid magnesium salt. Here, the water vaporization peak top temperature refers to the top peak of the temperature range at which residual water contained in the fatty acid magnesium salt and that cannot be removed by the drying process begins to desorb. For example, in the heat absorption graph of magnesium myristate by differential scanning calorimetry (DSC), the water vaporization peak top temperature is 102.1°C. The specific drying temperature varies depending on the type of fatty acid magnesium salt obtained, but for example, in the case of magnesium myristate, it is 72°C or lower. Drying at temperatures higher than 72°C tends to cause adhesion of fine particles, resulting in increased particle thickness. On the other hand, drying at temperatures lower than 40°C reduces drying properties, leaving a large amount of water in the compound, potentially reducing productivity. The fatty acid magnesium salt particles can be produced as described above.

[0034] The content of the fatty acid magnesium salt particles in the cosmetic of the present invention is preferably 1 to 60 mass %, more preferably 5 to 40 mass %, and particularly preferably 10 to 20 mass %, from the viewpoint of providing ease of use.

[0035] The cosmetic of the present invention contains fine particle titanium dioxide. By using the specific fatty acid magnesium salt particles in combination with fine particle titanium dioxide, usability such as moist feeling, transparency, and glossiness is improved.

[0036] The fine particle titanium dioxide preferably has an average primary particle diameter of 0.001 to 0.1 μm, more preferably 0.01 to 0.05 μm, from the viewpoint of being able to impart a moist feeling and a transparent finish after application. When so-called pigment-grade titanium dioxide particles with an average particle diameter of 0.2 μm or more are used, they have high covering power but result in a whitish, unnatural finish. However, the use of fine particle titanium dioxide in the present invention makes it possible to achieve a transparent, natural finish and to impart a moist feeling.

[0037] The content of the fine particle titanium dioxide in the cosmetic is preferably 10% by mass or less, more preferably 1 to 10% by mass, and particularly preferably 1 to 7% by mass, from the viewpoint of imparting a moist feeling.

[0038] The cosmetic of the present invention preferably further contains an oily component, which not only improves moisturizing properties but also suppresses the problem of powdery cosmetics, such as flying and scattering of powder. The oil component may be a liquid oil component or a solid oil component, and it is preferable to include a liquid oil component from the viewpoint of reducing powder aggregation and product stability.

[0039] Examples of liquid oily components include silicone oil, avocado oil, camellia oil, macadamia nut oil, corn oil, olive oil, rapeseed oil, egg yolk oil, sesame oil, persic oil, wheat germ oil, camellia oil, castor oil, linseed oil, safflower oil, cottonseed oil, perilla oil, soybean oil, peanut oil, tea seed oil, Japanese kaya oil, rice bran oil, Chinese tung oil, Japanese tung oil, jojoba oil, germ oil, triglycerin, glycerin trioctanoate, glycerin triisopalmitate, etc. These may be used in combination of two or more.

[0040] Examples of solid oily components include hydrocarbon waxes such as solid paraffin, ceresin, microcrystalline wax, polyethylene wax, hardened oil, beeswax, Japan wax, candelilla wax, etc., higher fatty acids such as stearic acid, lauric acid, myristic acid, behenic acid, etc., higher alcohols such as cetyl alcohol, stearyl alcohol, lauryl alcohol, etc. These may be used in combination of two or more.

[0041] From the viewpoint of product stability and usability, the content of oily ingredients in the cosmetic is preferably 10% by mass or less, more preferably 1 to 10% by mass, and particularly preferably 2 to 5% by mass.

[0042] The cosmetic of the present invention may further contain inorganic powder and organic powder. Examples of inorganic powders include inorganic pigments such as zinc oxide, red iron oxide, yellow iron oxide, and black iron oxide, mica, and talc. In the present invention, from the viewpoints of improving gloss, spreading property on the skin, and transparency, mica is preferably blended in an amount of 5 to 80% by mass, more preferably 20 to 60% by mass. Examples of mica include natural mica, synthetic phlogopite, synthetic iron phlogopite, and sericite, with synthetic phlogopite being more preferred. The organic powder includes organic pigments such as natural dyes. Furthermore, these powders may be surface-treated with a fluorine compound, a silicone compound, a fatty acid, or the like.

[0043] In addition to the above-mentioned components, the cosmetic of the present invention can contain other components typically used in cosmetics, etc., as appropriate, provided that the effects of the present invention are not impaired. Examples of such other components include surfactants, moisturizers, polymers, dyes, lower alcohols, polyhydric alcohols, antioxidants, UV absorbers, cosmetic ingredients, antibacterial agents, preservatives, pH adjusters, fragrances, etc.

[0044] The cosmetic of the present invention can be used in any formulation, such as a powder cosmetic, cream, emulsion, lotion, oily liquid cosmetic, oily solid cosmetic, or paste cosmetic. Powder cosmetics are preferred because they provide an excellent feel when applied to the skin. Powder cosmetics include powder solid cosmetic products and loose powders, with loose powders being most preferred.

[0045] Furthermore, the cosmetic of the present invention can be used, for example, as makeup cosmetics such as foundation, concealer, face powder (loose powder, pressed powder), control color, eye shadow, eyeliner, cheek color, body powder, perfume powder, and baby powder. [Example]

[0046] The present invention will be explained in more detail below with reference to Examples and Comparative Examples. Unless otherwise specified, the blending amounts of the components are expressed in mass % relative to the system in which the components are blended.

[0047] [Preparation of magnesium myristate 1] A 10-liter separable flask was charged with 500 g of myristic acid (NOF Corporation, NAA-142) and 5,600 g of water, and the mixture was heated to 90°C. Next, 250.0 g of a 48% by mass aqueous solution of sodium hydroxide was added, and the mixture was stirred at the same temperature (90°C) for 1 hour to obtain an aqueous solution of a fatty acid alkali compound salt. Subsequently, while maintaining the temperature at 90°C, 750.0 g of a 22% by mass aqueous solution of magnesium sulfate was added dropwise to the aqueous solution of sodium myristate over 40 minutes [dropping rate: 0.016 (mol / min)]. After completion of the dropwise addition, the mixture was maintained at 90°C and stirred for 30 minutes to mature. The resulting aqueous solution of fatty acid magnesium salt was cooled to 65°C or below. It was then filtered using a suction filter and washed eight times with 1,000 g of water. The resulting cake was dried at 60°C using a ventilated tray dryer and crushed using a mill to obtain magnesium myristate particles.

[0048] [Evaluation of Magnesium Myristate Particles] For magnesium myristate particles 1, the median diameter, particle size summary value A [value calculated from the 10% cumulative diameter on a volume basis D10 (μm), the median diameter on a volume basis D50 (μm), and the 90% cumulative diameter on a volume basis D90 (μm)], average particle thickness, major axis diameter, minor axis diameter, and aspect ratio were measured using the following devices and the methods described above.

[0049] (1) Grain size summary value A, median diameter 2.0 g of sample was placed in a 100 ml glass beaker, and 3-5 ml of a nonionic surfactant (e.g., NOF Corporation's Nonion NS-210) was added dropwise and mixed with a spatula. Next, 20 ml of purified water was added, and the mixture was dispersed ultrasonically to make a 100 ml volume, which was used as the measurement sample. The sample was then fed into a particle size distribution analyzer (Microtrac MT-3000, Nikkiso Co., Ltd.) and measured (principle: laser diffraction and scattering method). When a cumulative curve was calculated assuming the total volume of the powder mass to be measured as 100%, the particle diameters at the 10%, 50%, and 90% points of the cumulative curve were calculated as the 10% diameter (D10), 50% diameter (D50; median diameter), and 90% diameter (D90) (μm), respectively. The particle size summary value A was calculated from the obtained D10, D50, and D90.

[0050] (2) Average particle thickness, major axis diameter, minor axis diameter, aspect ratio, particle index Particle thickness was measured using a scanning electron microscope using the following method. Fatty acid magnesium salt particles were attached to double-sided carbon tape, and then the particle surfaces were coated with platinum particles by vapor deposition. The sample was observed at an accelerating voltage of 1.0 kV and a magnification of 2000x, and the thickness of any selected particle was measured. The thickness, major axis diameter, and minor axis diameter of any selected 10 particles were determined. The aspect ratio and particle index were also calculated using the following equations. Particle index = [(major axis diameter (μm) / minor axis diameter (μm)) / average thickness of particles (nm)] × 1000 aspect ratio = major axis diameter (μm) / minor axis diameter (μm)

[0051] The results of the above measurements are shown below. <Properties of magnesium myristate particles 1> Aspect ratio: 1.4 Particle index: 4.7 D10: 11.4 μm D50: 25.3 μm D90: 54.9 μm Average particle thickness: 309 nm Grain size summary value A: 1.7

[0052] [Magnesium myristate 2] For comparison, magnesium myristate (manufactured by Taihei Chemical Industry Co., Ltd.) with an aspect ratio of 2.52 and a median diameter (D50) of 17 μm was prepared.

[0053] [Zinc myristate] For comparison, zinc myristate (manufactured by NOF Corporation, zinc myristate) with an aspect ratio of 2.38, a median diameter of 10 μm, and an average thickness of 304 nm was prepared.

[0054] Example 1 and Comparative Examples 1 to 4: Loose Powder A loose powder having the composition shown in Table 1 was prepared according to the following manufacturing method. Manufacturing method: The powders excluding the oil (liquid oil: silicone oil) were mixed using a Henschel mixer, and after adding the oil, the mixture was mixed again using the Henschel mixer. The resulting mixture was filled into a container with a mesh.

[0055] [Usability evaluation] The cosmetic preparation (loose powder) obtained according to the present invention was evaluated for feel upon use, etc., based on the following criteria. The results are shown in Table 1.

[0056] (1) Moisturizing Ten expert panelists judged the moist feeling when the cosmetic was applied to the skin as follows, and rated the moist feeling as good if it was A or B. A: I feel it is very moisturizing. B: Feels moist C: Not very moisturizing D: Not moisturized. Feels squeaky.

[0057] (2)Transparency Ten expert panelists judged the transparency of the cosmetic product when applied to the skin as follows, and evaluated the transparency as good in cases A or B. A: There is almost no whitish feeling, and the finish is natural. B: It has a slight whitish tint, but the finish is natural. C: It looks whitish and the finish is a little unnatural. D: It looks very whitish and has an unnatural finish.

[0058] (3) Shine Ten expert panelists judged the glossiness of the cosmetics when applied to the skin as follows, and evaluated the glossiness as good if it was A or B. A: Very shiny B: Shiny C: Slightly shiny D: No shine

[0059] [Table 1]

[0060] Metal soap-treated synthetic mica: Magnesium stearate-treated synthetic phlogopite Lauroyl lysine: Amihope LL (registered trademark) manufactured by Ajinomoto Co., Inc. Titanium dioxide 1: Teika MT-100TV (fine particle titanium dioxide with an average particle size of 0.015 μm) Titanium dioxide 2: Triethoxycaprylylsilane-treated titanium dioxide (OTS-treated CR-50, manufactured by Daito Kasei Co., Ltd., titanium dioxide with an average particle size of 0.25 μm) Colorant 1: Yellow iron oxide Colorant 2: Red iron oxide

[0061] The above results show that the cosmetics of the examples containing magnesium myristate particles with specific properties and titanium dioxide particles have an excellent feel when used.

[0062] <Example 2 and Comparative Examples 5 to 8> Pressed powders having the compositions shown in Table 2 were prepared according to the following manufacturing method. Manufacturing method: The powders excluding the oil (semi-solid oil: petrolatum, liquid oil: triisostearin, triethylhexanoin, ethylhexyl methoxycinnamate) and surfactant (sorbitan sesquiisostearate) were mixed using a Henschel mixer, and after adding the oil and surfactant, they were mixed again using the Henschel mixer. The resulting mixture was pulverized using an atomizer and pressed in a molding machine.

[0063] [Usability evaluation] The cosmetic (pressed powder) obtained according to the present invention was evaluated for feel during use, etc., based on the same criteria as in Example 1. The results are shown in Table 2.

[0064] [Table 2]

[0065] Titanium dioxide 1: Teika MT-100TV (fine particle titanium dioxide with an average particle size of 0.015 μm) Titanium dioxide 2: Triethoxycaprylylsilane-treated titanium dioxide (OTS-treated CR-50, manufactured by Daito Kasei Co., Ltd., titanium dioxide with an average particle size of 0.25 μm) Colorant 1: Yellow iron oxide Colorant 2: Red iron oxide

[0066] The above results show that the cosmetics of the examples containing magnesium myristate particles with specific properties and titanium dioxide particles have an excellent feel when used.

[0067] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2020-164366) filed on September 30, 2020, the contents of which are incorporated herein by reference.

Claims

1. A cosmetic comprising fatty acid magnesium salt particles and fine titanium dioxide particles, The average primary particle diameter of the fine titanium dioxide particles is 0.001 to 0.1 μm, the fatty acid of the fatty acid magnesium salt particles has a carbon number of 12 to 22; The fatty acid magnesium salt particles have an aspect ratio represented by the following formula (1) of 1.0 or more and 2.0 or less, The cosmetic preparation, wherein the fatty acid magnesium salt particles have an average thickness of 250 to 600 nm. Aspect ratio = major axis diameter of particle (μm) / minor axis diameter of particle (μm) Formula (1)

2. The cosmetic preparation according to claim 1 , further comprising an oily component.

3. 3. The cosmetic according to claim 1, wherein the content of the fine particle titanium dioxide is 10% by mass or less.

4. The cosmetic according to claim 2 , wherein the oil component comprises a liquid oil component.

5. The cosmetic according to claim 2 or 4, wherein the content of the oily component is 10% by mass or less.

6. The cosmetic according to any one of claims 1 to 5, wherein the cosmetic is a powder cosmetic.

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