Skin external agent

Abstract

To provide a skin external agent having an excellent protective effect against ultraviolet rays, infrared rays and the like and hardly causing whitening when applied to the skin.SOLUTION: Provided is a skin external agent containing: a component (A) which is one or more metal oxides selected from the group consisting of a spherical metal oxide (A1) and a plate-like metal oxide (A2) having an average particle size of 350 nm or more and 2,500 nm or less; and a component (B) which is non-volatile oil. The content of the component (A) in the skin external agent is 2 mass% or more and 50 mass% or less, and the viscosity at 25°C is 2,500 mPa s or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an external preparation for skin.

Background Art

[0002] From the perspective of skin protection against sunlight, ultraviolet protection cosmetics such as sunscreen cosmetics are known. On the other hand, in recent years, due to the increasing health awareness, there is a demand for an external preparation for skin having a protective function against infrared rays. Regarding an external preparation for skin having an infrared ray protection function, for example, in Patent Document 1, as a technique related to an inhibitor that inhibits infrared rays from reaching tissues deeper than the skin tissue and prevents damage to those tissues by infrared rays, there is disclosed an inhibitor for near-infrared damage of living tissue containing an infrared transmission shielding agent composed of titanium oxide powder and zinc oxide powder. Patent Document 2 discloses a near-infrared ray protection cosmetic composition composed of titanium oxide powder and zinc oxide powder, which achieves both an excellent near-infrared protection effect and high transparency. In addition, Patent Documents 3 to 6 disclose an external preparation for skin containing a plate-shaped metal oxide having a predetermined shape as an external preparation for skin having a more excellent infrared ray protection effect.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

[0004] For skin protection against sunlight, there is a need for topical skin preparations that offer enhanced protection against ultraviolet and infrared rays. Furthermore, topical skin preparations should not leave a white cast on the skin when applied (hereinafter also referred to as "white residue"). The object of the present invention is to provide a topical skin preparation that has excellent protective effects against ultraviolet rays, infrared rays, etc., and leaves little white residue when applied to the skin. [Means for solving the problem]

[0005] The inventors have found that a topical skin preparation containing a metal oxide of a predetermined shape and quantity, as well as a non-volatile oil, and having a viscosity of a predetermined value or higher, can solve the above problem. In other words, the present invention relates to the following. [1] Component (A): One or more metal oxides selected from the group consisting of spherical metal oxides (A1) and plate-like metal oxides (A2) with an average particle size of 350 nm to 2,500 nm, and Ingredients (B): Non-volatile oil, A topical skin preparation containing the above, wherein the content of component (A) in the topical skin preparation is 2% by mass or more and 50% by mass or less, and the viscosity at 25°C is 2,500 mPa·s or more. [2] A method for protecting the skin from infrared radiation, comprising the step of applying the topical skin preparation described in [1] to the skin. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a topical skin preparation that has excellent protective effects against ultraviolet rays, infrared rays, etc., and leaves little white residue when applied to the skin. [Brief explanation of the drawing]

[0007] [Figure 1] This is an IR microscope image (score 5) of the evaluation of the uniformity of the skin topical preparation coating in Example 9. [Figure 2]This is an IR microscope image (score 1) of the evaluation of the uniformity of the skin topical preparation in Comparative Example 2. [Modes for carrying out the invention]

[0008] [Topical skin preparations] The topical skin preparation of the present invention is Component (A): One or more metal oxides selected from the group consisting of spherical metal oxides (A1) and plate-like metal oxides (A2) with an average particle size of 350 nm to 2,500 nm, and Ingredients (B): Non-volatile oil, A topical skin preparation containing the above, wherein the content of component (A) in the topical skin preparation is 2% by mass or more and 50% by mass or less, and the viscosity at 25°C is 2,500 mPa·s or more. The topical skin preparation of the present invention, having the above-described configuration, is a topical skin preparation that has excellent protective effects against ultraviolet rays, infrared rays, etc., and leaves little white residue when applied to the skin.

[0009] The reason why the above effects are obtained with the topical skin preparation of the present invention is not entirely clear, but it is thought to be as follows. It is known that in topical skin preparations containing metal oxides such as titanium dioxide, using larger particle sizes enhances the protective effect against ultraviolet and infrared radiation. However, simply using larger particle sizes of metal oxides has limitations in improving the protective effect, particularly against infrared radiation. Furthermore, when spherical metal oxides with large particle sizes are incorporated into a topical skin preparation, light scattering of visible light occurs at the particle surface when applied to the skin, resulting in the drawback of a white cast. Therefore, simply adjusting the particle size of the metal oxide used makes it difficult to simultaneously achieve improved protection against ultraviolet and infrared radiation and suppress the white cast when applied to the skin. Furthermore, increasing the content of metal oxides in topical skin preparations can improve their protective effect against ultraviolet and infrared rays, but increasing the content tends to result in a white cast when applied to the skin.

[0010] The skin external preparation of the present invention uses a metal oxide of a predetermined size and shape as component (A) in a predetermined amount, so that a protective effect against ultraviolet rays, infrared rays, etc. can be obtained, and it is also possible to suppress whitening when applied to the skin. Furthermore, in order to further improve the protective effect against ultraviolet rays, infrared rays, etc. in the skin external preparation containing a metal oxide, the present inventors have found that it is effective to uniformly apply the skin external preparation, particularly to uniformly arrange component (A), which is an active ingredient for protecting against ultraviolet rays, infrared rays, etc., on the skin surface, and for this purpose, rheology control of the skin external preparation is important. Specifically, when a skin external preparation with a low viscosity is applied to the skin, it is considered that component (A) with a high specific gravity is difficult to be retained in the coating film, so component (A) is likely to settle in the skin grooves. In particular, component (A) with a large particle size is likely to settle in the skin grooves and cannot be uniformly arranged on the skin surface, and it is considered that the protective effect against ultraviolet rays, infrared rays, etc. also decreases. In addition to component (A), the skin external preparation of the present invention contains a non-volatile oil as component (B), and since the viscosity is a predetermined value or more, it can suppress the sedimentation of component (A) into the skin grooves when applied to the skin and improve the uniform coating property, so it is considered that the protective effect against ultraviolet rays, infrared rays, etc. can be further enhanced.

[0011] <Definition> In the present invention, ultraviolet rays mean electromagnetic waves with a wavelength of 200 to 360 nm, and infrared rays mean electromagnetic waves with a wavelength of 780 nm to 1 mm. Among these, the skin external preparation of the present invention is particularly excellent in the near-infrared ray protective effect with a wavelength of 780 nm to 2500 nm. Due to this near-infrared ray protective effect, it is possible to obtain an effect of suppressing the rise in skin temperature and an effect of suppressing fatigue caused by sunlight irradiation. In this specification, the infrared ray protective rate at a wavelength of 825 nm is used as an index for the infrared ray protective effect.

[0012] <Viscosity> The external preparation for skin of the present invention has a viscosity at 25°C of 2,500 mPa·s or more, preferably 3,000 mPa·s or more, more preferably 5,000 mPa·s or more, still more preferably 8,000 mPa·s or more, and even more preferably 10,000 mPa·s or more from the viewpoint of improving the uniform coating property and suppressing the sedimentation of component (A) into skin grooves when applied to the skin, and improving the protective effects against ultraviolet rays, infrared rays, etc. Further, from the viewpoint of ease of spreading on the skin, it is preferably 200,000 mPa·s or less, more preferably 150,000 mPa·s or less, still more preferably 100,000 mPa·s or less, even more preferably 50,000 mPa·s or less, even more preferably 30,000 mPa·s or less, and even more preferably 20,000 mPa·s or less. And the viscosity at 25°C of the external preparation for skin of the present invention is 2,500 mPa·s or more, preferably 2,500 mPa·s or more and 200,000 mPa·s or less, more preferably 3,000 mPa·s or more and 200,000 mPa·s or less, still more preferably 5,000 mPa·s or more and 150,000 mPa·s or less, even more preferably 8,000 mPa·s or more and 100,000 mPa·s or less, even more preferably 8,000 mPa·s or more and 50,000 mPa·s or less, and even more preferably 10,000 mPa·s or more and 30,000 mPa·s or less. In other embodiments, the viscosity at 25°C of the external preparation for skin of the present invention is preferably 2,500 mPa·s or more and 150,000 mPa·s or less, more preferably 2,50,000 mPa·s or more and 100,000 mPa·s or less, still more preferably 2,500 mPa·s or more and 5,000 mPa·s or less, even more preferably 2,500 mPa·s or more and 30,000 mPa·s or less, and even more preferably 2,500 mPa·s or more and 20,000 mPa·s or less. The viscosity at 25°C of the external preparation for skin is a value measured at 25°C using a B-type viscometer, and specifically, it can be measured by the method described in the examples.

[0013] Means for adjusting the viscosity of the topical skin preparation of the present invention to the above range include selecting the type and content of component (A) used in the topical skin preparation, selecting the type and content of component (B), selecting the use and content of thickeners, emulsifiers, dispersants, aqueous media, etc., as described later, and selecting a method for dispersing component (A).

[0014] <Dosage Form, etc.> The dosage form of the topical skin preparation of the present invention is not particularly limited as long as the viscosity is within the above range, and is preferably liquid, gel, or cream in form from the viewpoint of ease of application to the skin. The dosage form of the topical skin preparation of the present invention is also preferably solid, such as a stick formulation, from the viewpoint of infrared protection, as long as the viscosity is within the above range. The topical skin preparation may be a non-aqueous composition or an emulsion composition, and the emulsion composition may be either an oil-in-water emulsion composition or an oil-in-water emulsion composition. An oil-in-water emulsion composition allows for easy viscosity adjustment, while an oil-in-water emulsion composition allows for easy formulation and improved uniform application. The topical skin preparation of the present invention is preferably an emulsified composition from the viewpoint of excellent usability, and is preferably a water-in-oil emulsion composition from the viewpoint of excellent protective effect against ultraviolet rays, infrared rays, etc., and excellent usability. Furthermore, the topical skin preparation of the present invention may be a skin cosmetic such as a lotion, cream, emulsion, serum, suntan, or makeup base, in addition to a topical skin preparation for protection against ultraviolet or infrared rays.

[0015] <Component (A): Metal oxide> The topical skin preparation of the present invention contains, as component (A), one or more metal oxides selected from the group consisting of spherical metal oxides (A1) and plate-like metal oxides (A2) with an average particle size of 350 nm to 2,500 nm. By containing component (A), the topical skin preparation of the present invention provides excellent protection against ultraviolet rays, infrared rays, etc., as well as skin temperature rise suppression and fatigue suppression effects, and also has the effect of suppressing white cast when applied to the skin.

[0016] (Component (A1): Spherical metal oxide with an average particle size of 350 nm to 2,500 nm) The component (A1) used in this invention is a spherical metal oxide with an average particle size of 350 nm to 2,500 nm. Here, "spherical" includes perfectly spherical and nearly perfectly spherical particles. Furthermore, component (A1) only needs to have a spherical shape in either the primary or secondary particles of the metal oxide. If component (A1) exists as secondary particles, the average particle size of component (A1) refers to the average value of the particle sizes of the secondary particles. The average particle size of component (A1) is 350 nm or more, preferably 400 nm or more, more preferably 700 nm or more, and even more preferably 800 nm or more, from the viewpoint of protective effects against ultraviolet rays, infrared rays, etc. Also, from the viewpoint of protective effects against ultraviolet rays, infrared rays, etc., and from the viewpoint of suppressing white cast when applied to the skin, it is 2,500 nm or less, preferably 2,000 nm or less, more preferably 1,800 nm or less, even more preferably 1,500 nm or less, and even more preferably 1,200 nm or less. Furthermore, the average particle size of component (A1) is 350 nm or more and 2,500 nm or less, preferably 400 nm or more and 2,000 nm or less, more preferably 700 nm or more and 2,000 nm or less, even more preferably 700 nm or more and 1,800 nm or less, even more preferably 700 nm or more and 1,500 nm or less, and even more preferably 800 nm or more and 1,200 nm or less. The average particle size of component (A1) is the median diameter (d 50 ) is, for example, determined by laser diffraction / light scattering particle size distribution measurement. In the measurement, a solvent that readily disperses component (A1) can be used as appropriate. For example, purified water can be used for metal oxides that have not been surface-treated, and silicone oil (e.g., methylpolysiloxane, cyclopentasiloxane, etc.) can be used for metal oxides that have been surface-treated with silicone, etc.

[0017] (Component (A2): Plate-like metal oxide) The component (A2) used in the present invention is a plate-shaped metal oxide. Component (A2) is plate-shaped and preferably has a thickness and aspect ratio within the range described later. When a coating film is formed on the skin surface using a topical skin preparation containing component (A2), the reflectance of light observed on the upper surface of the skin becomes high for infrared wavelengths and low for visible wavelengths due to the interference effect of light. Therefore, a higher infrared protection effect can be obtained, and the white cast when applied to the skin is also suppressed.

[0018] From the viewpoint of improving the infrared protection effect, the thickness of component (A2) is preferably 30 nm or more, more preferably 50 nm or more, even more preferably 60 nm or more, even more preferably 75 nm or more, even more preferably 90 nm or more, and even more preferably 100 nm or more. Furthermore, from the viewpoint of improving the infrared protection effect and suppressing white cast when applied to the skin, the thickness of component (A2) is preferably 360 nm or less, more preferably 330 nm or less, even more preferably 310 nm or less, even more preferably 280 nm or less, even more preferably 270 nm or less, even more preferably 230 nm or less, even more preferably 200 nm or less, and even more preferably 180 nm or less. Furthermore, the thickness of component (A2) is preferably 30 nm to 360 nm, more preferably 50 nm to 330 nm, even more preferably 60 nm to 310 nm, even more preferably 75 nm to 280 nm, even more preferably 90 nm to 270 nm, even more preferably 100 nm to 230 nm, even more preferably 100 nm to 200 nm, and even more preferably 100 nm to 180 nm. In this invention, the thickness of component (A2) refers to the length of the shortest axis in the plate-shaped metal oxide particles. The thickness of component (A2) can be determined from images observed using a scanning electron microscope (SEM). Specifically, component (A2) is observed using an SEM at a magnification of 10,000x, and the thickness of 50 particles in the observed image is measured. The average thickness per particle is then calculated to determine the thickness.

[0019] Furthermore, the aspect ratio of component (A2) is preferably 3 or more, more preferably 5 or more, even more preferably 10 or more, even more preferably 30 or more, even more preferably 50 or more, even more preferably 55 or more, and also preferably 300 or less, more preferably 230 or less, even more preferably 200 or less, even more preferably 140 or less, even more preferably 125 or less, and even more preferably 120 or less. The aspect ratio of component (A2) is preferably 3 to 300, more preferably 3 to 230, even more preferably 10 to 230, even more preferably 30 to 230, even more preferably 50 to 200, even more preferably 55 to 140, even more preferably 55 to 125, and even more preferably 55 to 120. The aspect ratio of component (A2) is determined by performing SEM observation under the same conditions as described above, measuring the length of the shortest axis (thickness) and the length of the longest axis (major axis) of 50 particles in the observed image, calculating the aspect ratio (major axis / thickness) of each particle, and then taking the average value. Specifically, the aspect ratio of component (A2) can be measured by the method described in the examples.

[0020] Component (A2) is preferably, from the viewpoint of improving infrared protection effect and suppressing white cast when applied to the skin, thickened to 30 nm or more and having an aspect ratio of 3 or more and 300 or less, more preferably thickened to 50 nm or more and having an aspect ratio of 3 or more and 230 or less, even more preferably thickened to 60 nm or more and having an aspect ratio of 10 or more and 230 or less, and even more preferably thickened to 75 nm or more and having an aspect ratio of 280 nm or less. The aspect ratio is 30 to 230, more preferably 90 nm to 270 nm thick and an aspect ratio of 50 to 200, more preferably 100 nm to 230 nm thick and an aspect ratio of 55 to 140, more preferably 100 nm to 200 nm thick and an aspect ratio of 55 to 125, and more preferably 100 nm to 180 nm thick and an aspect ratio of 55 to 120.

[0021] A topical skin preparation may contain either component (A1) or component (A2) as component (A), or it may contain both component (A1) and component (A2). When component (A) contains both component (A1) and component (A2), the mass ratio is not particularly limited, but from the viewpoint of improving the infrared protection effect and suppressing white cast when applied to the skin, the mass ratio (A1) / (A2) is preferably in the range of 10 / 90 to 90 / 10, more preferably 20 / 80 to 80 / 20, and even more preferably 30 / 70 to 70 / 30. Furthermore, topical skin preparations may contain two or more components (A1) as component (A), and may also contain two or more components (A2).

[0022] Examples of metal oxides in components (A1) and (A2) include titanium oxide, zinc oxide, zirconium oxide, iron oxide, aluminum oxide, and cerium oxide. Among these, from the viewpoint of protective effects against ultraviolet rays, infrared rays, etc., and particularly from the viewpoint of improving infrared ray protection, it is preferable to have one or more selected from the group consisting of titanium dioxide and zinc oxide, and more preferably titanium dioxide. The crystalline structure of titanium dioxide can be rutile, anatase, or amorphous, but the rutile form is preferred from the viewpoint of protective effects against ultraviolet and infrared rays.

[0023] Components (A1) and (A2) may be untreated metal oxides, or metal oxides that have undergone surface treatment such as hydrophobic treatment by known methods as necessary to improve dispersibility in topical skin preparations. Components (A1) and (A2) are distinguished from particles other than metal oxides whose surfaces have been treated with metal oxides.

[0024] Surface treatment agents used for surface treatment of metal oxides include silicones, alkylalkoxysilanes, fluorine-containing compounds such as perfluoroalkyl phosphates and perfluoroalcohols, amino acids such as N-acyl glutamic acid, and others such as lecithin, metal soaps, fatty acids such as stearic acid, and alkyl phosphates. Among these, one or more selected from the group consisting of silicones and alkylalkoxysilanes are preferred. The silicone used as a surface treatment agent is not particularly limited, and examples include various silicone oils such as methylpolysiloxane, dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane [hydrogen dimethicone], methylcyclopolysiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, octamethyltrisiloxane, tetradecamethylhexasiloxane, dimethylsiloxane-methyl(polyoxyethylene)siloxane-methyl(polyoxypropylene)siloxane copolymer, dimethylsiloxane-methyl(polyoxyethylene)siloxane copolymer, dimethylsiloxane-methyl(polyoxypropylene)siloxane copolymer, dimethylsiloxane-methylcetyloxysiloxane copolymer, dimethylsiloxane-methylstearoxysiloxane copolymer, and (alkyl acrylate / dimethicone) copolymer (ASC). As alkylalkoxysilanes used as surface treatment agents, those having branched or linear alkyl groups with 6 to 20 carbon atoms are preferred, and in particular, octyltriethoxysilane and octyltrimethoxysilane can be mentioned.

[0025] From the viewpoint of improving the dispersibility of component (A) in topical skin preparations and further enhancing the protective effect against ultraviolet rays, infrared rays, etc., it is preferable to use one or more surface treatment agents selected from the group consisting of methylpolysiloxane, dimethylpolysiloxane, methylhydrogenpolysiloxane, (alkyl acrylate / dimethicone) copolymer, and octyltriethoxysilane as surface treatment agents for metal oxides. When component (A1) or component (A2) is a surface-treated metal oxide, the amount of coating by the surface treatment agent is preferably 1% by mass or more and 9% by mass or less, and more preferably 2% by mass or more and 8% by mass or less, relative to the total amount of component (A1) or component (A2), from the viewpoint of improving dispersibility in the topical skin preparation.

[0026] From the viewpoint of improving infrared protection and suppressing white cast when applied to the skin, it is preferable that component (A) contains component (A2). Here, a higher optical interference effect can be obtained if the metal oxide constituting component (A2) is a high refractive index material. For this reason, component (A) more preferably contains one or more selected from the group consisting of plate-shaped titanium oxide and plate-shaped zinc oxide as component (A2), and even more preferably contains plate-shaped titanium oxide. When component (A) contains component (A2), the content of component (A2) in component (A) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more, and 100% by mass or less, from the viewpoint of improving the infrared protection effect and suppressing white cast when applied to the skin.

[0027] The content of component (A) in the topical skin preparation is 2% by mass or more, preferably 3% by mass or more, and more preferably 5% by mass or more, from the viewpoint of improving the protective effect against ultraviolet rays, infrared rays, etc. Furthermore, from the viewpoint of suppressing white cast when applied to the skin, it is 50% by mass or less. Furthermore, from the viewpoint of improving the infrared protection effect and suppressing white cast when applied to the skin, the content of component (A) in the topical skin preparation is more preferably within the following range. When component (A) is spherical titanium dioxide with an average particle size of 350 nm or more and less than 800 nm, the content of the spherical titanium dioxide in the topical skin preparation is more preferably 5% by mass or more and 30% by mass or less, and even more preferably 5% by mass or more and 25% by mass or less. When component (A) is spherical titanium dioxide with an average particle size of 800 nm or more and 2,500 nm or less, the content of the spherical titanium dioxide in the topical skin preparation is more preferably 5% by mass or more and 40% by mass or less, and even more preferably 5% by mass or more and 30% by mass or less. When component (A) is plate-shaped titanium dioxide, the content of the plate-shaped titanium dioxide in the topical skin preparation is more preferably 5% by mass or more and 30% by mass or less. When component (A) is spherical zinc oxide or plate-shaped zinc oxide with an average particle size of 350 nm or more and 2,500 nm or less, the content of the spherical zinc oxide or plate-shaped zinc oxide in the topical skin preparation is more preferably 7% by mass or more and 50% by mass or less, and even more preferably 10% by mass or more and 50% by mass or less.

[0028] Furthermore, the content of component (A) in the non-volatile component of the topical skin preparation is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, from the viewpoint of improving the protective effect against ultraviolet rays, infrared rays, etc. Furthermore, from the viewpoint of suppressing white cast when applied to the skin, it is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and even more preferably 20% by mass or less. And the content of component (A) in the non-volatile component of the topical skin preparation is preferably 3% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 40% by mass or less, even more preferably 10% by mass or more and 30% by mass or less, and even more preferably 10% by mass or more and 20% by mass or less. In this context, "non-volatile components in topical skin preparations" refers to the components obtained by excluding water, the aqueous medium described later, and volatile oils (oils other than component (B)) from the total amount of the topical skin preparation.

[0029] The viscosity (mPa·s) of the topical skin preparation with respect to the content (mass%) of component (A) in the topical skin preparation is, from the viewpoint of improving uniform application and uniformly distributing component (A) on the skin surface, preferably as [viscosity of topical skin preparation (mPa·s) / content (mass%) of component (A) in the topical skin preparation] is 100 or more, more preferably 250 or more, even more preferably 300 or more, and still more preferably 350 or more. Furthermore, it is preferably 25,000 or less, more preferably 20,000 or less, even more preferably 15,000 or less, still more preferably 10,000 or less, still more preferably 5,000 or less, and still more preferably 3,000 or less. Furthermore, the [viscosity of the topical skin preparation (mPa·s) / content of component (A) in the topical skin preparation (mass%)] is preferably 100 to 25,000, more preferably 250 to 20,000, even more preferably 300 to 15,000, even more preferably 350 to 10,000, even more preferably 350 to 5,000, and even more preferably 350 to 3,000.

[0030] A commercially available metal oxide can also be used as component (A). For example, commercially available spherical titanium oxide used as component (A1) includes "ST-750EC" manufactured by Titanium Industries Co., Ltd. and "R-38L" manufactured by Sakai Chemical Industry Co., Ltd., while commercially available spherical zinc oxide includes "LP-ZINC-2KS" manufactured by Sakai Chemical Industry Co., Ltd. Examples of commercially available plate-shaped titanium oxide used as component (A2) include CQV's "Featheleve PT-9001K", "Featheleve PT-7001K", "Featheleve PT-7401K", "Featheleve PT-7801K", "Featheleve PT-7901K", and surface-coated versions thereof. Examples of commercially available plate-shaped zinc oxide include Sakai Chemical Industry Co., Ltd.'s "XZ-1000F-LP".

[0031] <Component (B): Non-volatile oil> The topical skin preparation of the present invention contains a non-volatile oil as component (B) in order to easily adjust to a desired viscosity and enhance the protective effect against ultraviolet rays, infrared rays, etc., by improving uniform application. A non-volatile oil is defined as one in which the evaporation rate at 25°C for 6 hours is less than 20%, as measured by the following method (1). Method (1): Place a 90mm diameter filter paper in a 120mm diameter glass petri dish, place 1g of the sample on the filter paper, and store in a room at 65% RH (25°C). After 6 hours, measure the residue of the sample and calculate the amount of evaporation.

[0032] Furthermore, component (B) is preferably liquid at 1 atmosphere and 25°C. More specifically, component (B) has a viscosity at 25°C of preferably 500 mPa·s or less, more preferably 300 mPa·s or less, even more preferably 100 mPa·s or less, even more preferably 50 mPa·s or less, and preferably 5 mPa·s or more. The viscosity can be measured using a Type B viscometer "TVB-10" (manufactured by Toki Sangyo Co., Ltd.) under the conditions of rotor No. 1, 25°C, 60 rpm, and 1 minute.

[0033] Specific examples of component (B) include non-volatile oils that are liquid at 25°C, such as one or more selected from the group consisting of ester oils, silicone oils, hydrocarbon oils, higher fatty acids, and higher alcohols.

[0034] Examples of non-volatile liquid ester oils include one or more selected from the group consisting of monoesters of fatty acids having 8 to 18 carbon atoms and branched alcohols having 2 to 22 carbon atoms, triesters of branched fatty acids having 6 to 18 carbon atoms and glycerin, diesters of dicarboxylic acids having 2 to 18 carbon atoms and branched alcohols having 2 to 18 carbon atoms, diesters of fatty acids having 6 to 18 carbon atoms and dialcohols having 2 to 10 carbon atoms, and alkyl benzoates. Examples of monoesters of fatty acids having 8 to 18 carbon atoms and branched alcohols having 2 to 22 carbon atoms include isononyl isononanoate, isotridecyl isononanoate, isopropyl myristate, isocetyl myristate, octyldodecyl myristate, isopropyl palmitate, ethylhexyl palmitate, and 2-hexyldecyl palmitate. Examples of triesters of fatty acids with 6 to 18 carbon atoms and glycerin include glyceryl tri-2-ethylhexanoate and glyceryl tri(caprylic / capric acid). Examples of diesters of dicarboxylic acids having 2 to 18 carbon atoms and branched alcohols having 2 to 18 carbon atoms include di2-ethylhexyl sebacate, diisopropyl sebacate, and diisostearyl malate. Examples of diesters of fatty acids having 6 to 18 carbon atoms and dialcohols having 2 to 10 carbon atoms include diethylene glycol dicaprate, neopentyl glycol dicaprate, and neopentyl glycol di2-ethylhexanoate. Examples of alkyl benzoates include alkyl benzoates (C12-C15) (for example, Finsolve TN; manufactured by Innospec Active Chemicals LLC).

[0035] Among the ester oils used as component (B), from the viewpoint of ease of viscosity adjustment, improvement of solubility of thickeners described later, and suppression of stickiness when applied to the skin, the following group is selected: monoesters of fatty acids having 12 to 18 carbon atoms and branched alcohols having 2 to 22 carbon atoms; triesters of branched fatty acids having 6 to 18 carbon atoms and glycerin; diesters of dicarboxylic acids having 2 to 18 carbon atoms and branched alcohols having 2 to 18 carbon atoms; diesters of fatty acids having 6 to 18 carbon atoms and branched dialcohols having 2 to 10 carbon atoms; and alkyl benzoates (C12-C15). Preferably, one or more are selected from the group consisting of isopropyl myristate, isocetyl myristate, octyldodecyl myristate, isopropyl palmitate, ethylhexyl palmitate, 2-hexyldecyl palmitate, glyceryl tri-2-ethylhexanoate, diisopropyl sebacate, di-2-ethylhexyl sebacate, diisostearyl malate, neopentyl glycol di-2-ethylhexanoate, neopentyl glycol dicaprate, and alkyl benzoates (C12-C15), with isopropyl palmitate being even more preferred.

[0036] As the non-volatile liquid silicone oil, methylpolysiloxane is preferred, and methylpolysiloxane with a viscosity of 20 mPa·s or less at 25°C is more preferred.

[0037] Examples of non-volatile liquid hydrocarbon oils include liquid paraffin, light liquid isoparaffin such as hydrogenated polyisobutene, heavy liquid isoparaffin, liquid ozokerite, squalane, pristane, squalene, and isohexadecane.

[0038] Examples of non-volatile liquid higher fatty acids include fatty acids with 12 to 22 carbon atoms, specifically oleic acid, isostearic acid, linoleic acid, and linolenic acid. Examples of non-volatile liquid higher alcohols include alcohols with 12 to 28 carbon atoms, specifically oleyl alcohol, 2-decyltetradecinol, dodecanol, isostearyl alcohol, octyldodecanol, and others.

[0039] Component (B) is a non-volatile oil that is liquid at 25°C, preferably one or more selected from the group consisting of ester oils, silicone oils, and hydrocarbon oils, from the viewpoint of ease of viscosity adjustment, improvement of solubility of thickeners described later, and suppression of stickiness when applied to the skin. More preferably, it is one or more selected from the group consisting of ester oils and silicone oils, and even more preferably ester oils and silicone oils.

[0040] The content of component (B) in the topical skin preparation of the present invention is preferably 1% by mass or more, more preferably 5% by mass or more, from the viewpoint of easily adjusting to the desired viscosity and improving uniform application, thereby enhancing the protective effect against ultraviolet rays, infrared rays, etc. Furthermore, from the viewpoint of suppressing stickiness when applied to the skin, it is preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less, and even more preferably 65% ​​by mass or less. Furthermore, if the topical skin preparation of the present invention is a water-in-oil emulsion composition, the content of component (B) in the topical skin preparation is more preferably 15% by mass or more, even more preferably 20% by mass or more, even more preferably 25% by mass or more, even more preferably 30% by mass or more, and even more preferably 35% by mass or more, from the viewpoint of making it a water-in-oil type. When the topical skin preparation of the present invention is an oil-in-water emulsion composition, the content of component (B) in the topical skin preparation is more preferably 30% by mass or less, more preferably 20% by mass or less, and more preferably 10% by mass or less, from the viewpoint of making it an oil-in-water type.

[0041] In the topical skin preparation of the present invention, the mass ratio of the content of component (B) to the content of component (A) [(B) / (A)] is preferably 0.05 or more, more preferably 0.1 or more, even more preferably 0.2 or more, even more preferably 0.5 or more, even more preferably 1 or more, even more preferably 2 or more, even more preferably 3 or more, and even more preferably 3.6 or more, from the viewpoint of enhancing the protective effect against ultraviolet rays, infrared rays, etc. by improving uniform application, and from the viewpoint of improving the feel of use. From the viewpoint of suppressing stickiness when applied to the skin, it is preferably 60 or less, more preferably 50 or less, even more preferably 30 or less, even more preferably 20 or less, even more preferably 10 or less, and even more preferably 8 or less. Furthermore, the mass ratio [(B) / (A)] is preferably 0.05 to 60, more preferably 0.1 to 50, even more preferably 0.2 to 30, even more preferably 0.5 to 20, even more preferably 1 to 10, even more preferably 2 to 10, even more preferably 3 to 10, and even more preferably 3.6 to 8.

[0042] Furthermore, from the viewpoint of protective effects against ultraviolet rays, infrared rays, etc., and from the viewpoint of suppressing white cast when applied to the skin, the total content of component (A) and component (B) in the topical skin preparation is preferably 2% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, even more preferably 30% by mass or more, even more preferably 40% by mass or more, even more preferably 45% by mass or more, even more preferably 47% by mass or more, and even more preferably 50% by mass or more, and also 100% by mass or less.

[0043] <Thickening agent> The topical skin preparation of the present invention preferably further contains a thickening agent from the viewpoint of facilitating viscosity adjustment, improving uniform application, and enhancing protective effects against ultraviolet rays, infrared rays, etc. In the present invention, "thickening agent" means an additive that has the effect of increasing the thickness of the topical skin preparation. Examples of thickening agents include oil-based thickening agents and water-soluble thickening agents, which can be appropriately selected depending on the dosage form of the topical skin preparation. For example, if the topical skin preparation is a water-in-oil emulsion composition, an oil-based thickening agent (oil gelling agent) is preferred from the viewpoint of easily increasing the thickness without changing the formulation. Examples of oil thickeners include those commonly used in topical skin preparations, such as solid waxes, organically modified clay minerals, fumed silica, colloidal silica, dextrin fatty acid esters, metal soaps, sucrose fatty acid esters, and amino acid-based gelling agents. Of these, from the viewpoint of facilitating viscosity adjustment and improving uniform application, as well as enhancing protective effects against ultraviolet and infrared rays, it is preferable to use one or more selected from the group consisting of solid waxes, organically modified clay minerals, dextrin fatty acid esters, and amino acid-based gelling agents, and more preferably one or more selected from the group consisting of solid waxes, organically modified clay minerals, and dextrin fatty acid esters.

[0044] Examples of solid waxes include those with a melting point of 61°C or higher. Waxes with a melting point of 61°C or higher exhibit solid properties at 25°C. In this invention, the melting point is measured by one of the following methods: Method 1, Method 2, or Method 3 of the General Test Methods of the Quasi-Drug Raw Materials Standards. The method to be adopted depends on the specific measurement method described in the Quasi-Drug Raw Materials Standards for each component. If there is no description, the measurement method is selected considering the melting point. Specifically, Method 1 is generally used for materials with a melting point significantly exceeding 80°C, Method 2 for solid fats with lower melting points, and Method 3 for materials referred to as paste oils in catalogs, etc. However, any method that can measure the melting point is acceptable.

[0045] Waxes with a melting point of 61°C or higher are not particularly limited as long as they are commonly used in topical skin preparations, and examples include mineral waxes such as ozokerite and ceresin; petroleum waxes such as paraffin and microcrystalline wax; synthetic hydrocarbons such as Fischer-Tropsch wax, polyethylene wax, and synthetic hydrocarbon wax; plant waxes such as carnauba wax, candelilla wax, rice wax, and sunflower wax; animal waxes such as beeswax and whale wax; and synthetic waxes such as silicone wax and synthetic beeswax. Of these, one or more selected from the group consisting of petroleum-based waxes and silicone waxes are preferred from the viewpoint of facilitating viscosity adjustment, improving uniform application, and enhancing protective effects against ultraviolet and infrared rays. Furthermore, from the viewpoint of facilitating viscosity adjustment, improving uniform application, and enhancing protective effects against ultraviolet and infrared rays, these waxes are preferably melted at 65°C or higher and 140°C or lower, and more preferably at 70°C or higher and 110°C or lower.

[0046] The organically modified clay minerals are not particularly limited as long as they are commonly used in topical skin preparations. Examples include cationically modified clay minerals obtained by treating layered clay minerals such as bentonite, laponite, hectorite, montmorillonite, and aluminum magnesium silicate with a quaternary ammonium salt type cationic surfactant. Specifically, one or more selected from the group consisting of benzyldimethylstearylammonium chloride and dimethyldistearylammonium chloride are preferred, with dimethyldistearylammonium chloride being more preferred. Examples of commercially available organically modified clay minerals include "Benton 38," "Benton 38VCG," and "Benton 27" manufactured by Elementis Japan.

[0047] Organically modified clay minerals can also be used as a premixed gel diluted with a solvent, from the viewpoint of improving workability and thickening effect. Specifically, a premixed gel in which organically modified clay minerals are dispersed in a solvent beforehand is preferred. The solvent is not limited as long as it can be gelled by the organically modified clay minerals, but from the viewpoint of improving the thickening effect, octyldodecanol, mineral oil, etc. are preferred. Furthermore, from the viewpoint of efficiently dispersing the organically modified clay minerals, it is preferable to further include polar additives such as propylene carbonate, ethanol, water, and various surfactants. The content of organically modified clay minerals in the premix gel is preferably 5% by mass or more, more preferably 8% by mass or more, even more preferably 10% by mass or more, preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 18% by mass or less, from the viewpoint of improving workability and thickening effect, as well as suppressing oil separation of the premix gel itself. Examples of commercially available premix gels include "Benton Gel EUGV," "Benton Gel MIOV," "Benton Gel VS-5 PCV," "Benton Gel PTM V," and "Benton Gel GTCC V" from Elementis Japan.

[0048] The dextrin fatty acid ester is not particularly limited as long as it is commonly used in topical skin preparations. However, from the viewpoint of facilitating viscosity adjustment, improving uniform application, and enhancing protective effects against ultraviolet and infrared rays, an ester of a fatty acid having 8 to 24 carbon atoms and dextrin is preferred, and an ester of a fatty acid having 14 to 20 carbon atoms and dextrin is more preferred. Furthermore, it is preferable that the average degree of polymerization of the dextrin is 3 to 150. Specifically, examples include dextrin palmitate, dextrin stearate, palmitic acid / dextrin stearate, dextrin oleate, dextrin isopalmitate, dextrin isostearate, dextrin myristate, and dextrin palmitate / 2-ethylhexanoate. Of these, palmitate dextrin, myristate dextrin, and palmitate-2-ethylhexanoate dextrin are preferred from the viewpoint of facilitating viscosity adjustment, improving uniform coating properties, and enhancing protective effects against ultraviolet and infrared rays, and those containing at least palmitate dextrin are more preferred. Commercially available dextrin fatty acid esters include palmitate dextrin ("Leopal KL2", "Leopal KS2", "Leopal TL2"), palmitate-2-ethylhexanoate dextrin "Leopal TT2", and myristate dextrin "Leopal MKL2", all manufactured by Chiba Flour Milling Co., Ltd.

[0049] As for the amino acid-based gelling agent, any one commonly used in topical skin preparations can be used without particular limitations. Specifically, dibutyl lauroyl glutamide and dibutyl ethylhexanoyl glutamide are preferred. Examples of commercially available amino acid-based gelling agents include dibutyl lauroyl glutamide "GP-1" and dibutyl ethylhexanoyl glutamide "EB-21" manufactured by Ajinomoto Co., Inc.

[0050] Amino acid-based gelling agents can also be used as a premixed gel diluted and dissolved in a solvent, from the viewpoint of improving workability and thickening effect. Specifically, a premixed gel in which an amino acid-based gelling agent is dissolved in a solvent beforehand is preferred. The solvent is not limited as long as it can be gelled by the amino acid-based gelling agent, but from the viewpoint of improving the thickening effect, octyldodecanol, isostearic acid, etc. are preferred. The content of the amino acid-based gelling agent in the premix gel is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, preferably 45% by mass or less, more preferably 40% by mass or less, and even more preferably 36% by mass or less, from the viewpoint of improving workability and thickening effect, as well as suppressing oil separation of the premix gel itself. Examples of commercially available premixed gels include "AJK-OD2046" (containing 20% ​​by mass of amino acid-based gelling agent) and "AJK-IS3613" (containing 36% by mass of amino acid-based gelling agent) from Higher Alcohol Industry Co., Ltd.

[0051] One or more types of thickening agents may be used. When a topical skin preparation contains a thickening agent, the content of the thickening agent in the topical skin preparation is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, and even more preferably 3% by mass or more, from the viewpoint of viscosity adjustment, improving uniform application, and enhancing protective effects against ultraviolet rays, infrared rays, etc. Also, preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 25% by mass or less, even more preferably 20% by mass or less, and even more preferably 15% by mass or less. Furthermore, the content of the thickening agent in the topical skin preparation is preferably 0.5% by mass or more and 50% by mass or less, more preferably 0.5% by mass or more and 30% by mass or less, even more preferably 1% by mass or more and 25% by mass or less, even more preferably 2% by mass or more and 20% by mass or less, and even more preferably 3% by mass or more and 15% by mass or less.

[0052] <Emulsifier> The topical skin preparation of the present invention may further contain an emulsifier from the viewpoint of improving the dispersibility of component (A) and preparing an emulsified composition. In the present invention, "emulsifier" means an additive other than the thickener that has emulsifying properties. The emulsifier used in the present invention may be either a low-molecular-weight emulsifier or a high-molecular-weight emulsifier, but a high-molecular-weight emulsifier is preferred from the viewpoint of improving the dispersibility of component (A) and ease of viscosity adjustment. Preferred polymer emulsifiers include those having hydrophilic and hydrophobic parts, such as alkyl-modified polyacrylic acid polymers, alkyl-modified polysaccharide polymers, and oxazoline-modified silicones.

[0053] Examples of alkyl-modified polyacrylic acid polymers include (meth)acrylic acid / (meth)acrylate alkyl copolymers and alkyl acrylate / alkyl methacrylate / polyoxyethylene stearyl methacrylate copolymers.

[0054] Examples of alkyl-modified polysaccharide polymers include hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, methylcellulose, sodium carboxymethylcellulose, stearoxyhydroxypropylmethylcellulose, laureth-13PG hydroxyethylcellulose, and stearoxyPG hydroxyethylcellulose sulfonate.

[0055] Examples of oxazoline-modified silicones include polymers composed of hydrophilic segments with repeating N-acylalkyleneimines and organopolysiloxane segments. For example, N-propionyl polyethyleneimine-methylpolysiloxane copolymer (POLYSILICONE-9) can be cited.

[0056] One or more emulsifiers can be used. Among the above, oxazoline-modified silicone is preferred from the viewpoint of improving the dispersibility of component (A) and ease of viscosity adjustment.

[0057] When the topical skin preparation of the present invention contains an emulsifier, the content of the emulsifier in the topical skin preparation is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and also preferably 15% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, even more preferably 3% by mass or less, and even more preferably 1% by mass or less. Furthermore, the content of the emulsifier in the topical skin preparation is preferably 0.1% by mass or more and 15% by mass or less, more preferably 0.1% by mass or more and 10% by mass or less, even more preferably 0.1% by mass or more and 5% by mass or less, even more preferably 0.1% by mass or more and 3% by mass or less, and even more preferably 0.2% by mass or more and 1% by mass or less.

[0058] <Dispersant> The topical skin preparation of the present invention may further contain a dispersant from the viewpoint of improving the dispersibility of component (A). In the present invention, "dispersant" means an additive that mainly contributes to improving the dispersibility of component (A).

[0059] As a dispersant used in the present invention, a nonionic surfactant is preferred from the viewpoint of improving the dispersibility of component (A). The nonionic surfactant is not particularly limited as long as it is one that is commonly used in topical skin preparations, and silicone-based surfactants, fluorine-containing surfactants, etc., can also be used. Examples of nonionic surfactants used as dispersants include alkanolamides, amine oxides, polyoxyethylene alkyl ethers, polyoxyethylene hydrogenated castor oil, polyoxyethylene fatty acid amides, polyoxyethylene alkylamines, alkyl saccharides, α-monoalkyl glyceryl ethers, and polyether-modified silicones. One or more of these can be used.

[0060] From the viewpoint of further improving the dispersibility of component (A), the dispersant preferably contains a nonionic silicone-based surfactant, and more preferably contains a polyether-modified silicone. Examples of commercially available polyether-modified silicones used as dispersants include "KF-6012" (poly(oxyethylene-oxypropylene)methylpolysiloxane copolymer), "KF-6015", "KF-6017", "KF-6028", and "KF-6038" from Shin-Etsu Chemical Co., Ltd., and "SH3775M" (all polyoxyethylene-methylpolysiloxane copolymers) and "SH3772C" from Dow Toray Industries, Inc.

[0061] As a nonionic surfactant other than those mentioned above used as a dispersant, polyoxyethylene alkyl ether type nonionic surfactants are more preferred. Examples of commercially available polyoxyethylene alkyl ether type nonionic surfactants include Kao Corporation's "Emulgen 121-G" (polyoxyethylene (21) lauryl ether), Kao Corporation's "Emulgen 1620G" (polyoxyethylene (20) 2-hexyldecyl ether), and Kao Corporation's "Emulgen 2020G" (polyoxyethylene (20) octyldodecyl ether).

[0062] One or more types of dispersants can be used. When the topical skin preparation of the present invention contains a dispersant, the content of the dispersant in the topical skin preparation is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, even more preferably 0.5% by mass or more, and also preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, from the viewpoint of improving the dispersibility of component (A). Furthermore, the content of the dispersant in the topical skin preparation is preferably 0.1% by mass or more and 15% by mass or less, more preferably 0.3% by mass or more and 10% by mass or less, and even more preferably 0.5% by mass or more and 5% by mass or less.

[0063] <Water> From the viewpoint of providing a refreshing feeling, the topical skin preparation of the present invention preferably further contains water. When a topical skin preparation contains water, the water content in the preparation can be appropriately selected depending on the dosage form, but is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 8% by mass or more, even more preferably 10% by mass or more, preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less.

[0064] <Aqueous medium> The topical skin preparation of the present invention may further contain an aqueous medium other than water, from the viewpoint of dispersing component (A) and dispersing or dissolving other formulation components to further improve uniform application. Examples of such aqueous mediums include monohydric alcohols having 4 or fewer carbon atoms, such as ethanol, isopropyl alcohol, and butyl alcohol; and low molecular weight diols and triols having 6 or fewer carbon atoms, such as 1,3-butylene glycol, glycerin, ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol. Among these, one or more selected from the group consisting of monohydric alcohols having 4 or fewer carbon atoms are preferred, and ethanol is more preferred.

[0065] When a topical skin preparation contains an aqueous medium, the content of the aqueous medium in the topical skin preparation can be appropriately selected depending on the dosage form, but from the viewpoint of dispersing component (A) and dispersing or dissolving other components to further improve uniform application, it is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and even more preferably 10% by mass or less. Furthermore, the content of the aqueous medium in the topical skin preparation is preferably 0.1% by mass or more and 50% by mass or less, more preferably 0.1% by mass or more and 30% by mass or less, even more preferably 0.1% by mass or more and 20% by mass or less, and even more preferably 0.5% by mass or more and 10% by mass or less.

[0066] Furthermore, the total content of water and aqueous media in the topical skin preparation is preferably 2% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, preferably 70% by mass or less, more preferably 60% by mass or less, even more preferably 40% by mass or less, and even more preferably 35% by mass or less, from the viewpoint of further improving the refreshing feeling of use.

[0067] <Other ingredients> In addition to the above-mentioned components, the topical skin preparation of the present invention may also contain other components as needed, such as ultraviolet absorbers, ultraviolet scattering agents, volatile oils, antiperspirants, fragrances, moisturizers, bactericides, pH adjusters, antioxidants, preservatives, and the like.

[0068] (UV absorber) The topical skin preparation of the present invention may further contain an ultraviolet absorber from the viewpoint of improving its ultraviolet protection effect. The UV absorber is preferably an organic UV absorber other than component (B), and can be an oil-soluble or water-soluble organic UV absorber. From the viewpoint of improving UV protection, suppressing white cast when applied to the skin, and suppressing stickiness, the UV absorber is preferably an oil-soluble organic UV absorber. In this invention, "oil-soluble" means not water-soluble, and specifically means that the solubility in water at 25°C is 1 w / w% or less. Furthermore, from the viewpoint of obtaining the effects of the present invention, it is preferable that the ultraviolet absorber does not include inorganic ultraviolet absorbers, such as an ultraviolet absorber in which the surface of an inorganic filler is coated with an ultraviolet absorbing material.

[0069] Oil-soluble organic ultraviolet absorbers can include salicylic acid-based ultraviolet absorbers, cinnamic acid-based ultraviolet absorbers, benzoylmethane-based ultraviolet absorbers, and other oil-soluble organic ultraviolet absorbers. For example, salicylic acid-based UV absorbers such as homomenthyl salicylate and octyl salicylate; Cinnamic acid-based UV absorbers such as 2-ethylhexyl paramethoxycinnamate (e.g., BASF's "Ubinal MC80"), glyceryl mono-2-ethylhexanoate diparamethoxycinnamate, methyl 2,5-diisopropylcinnamate, methyl bis(trimethylsiloxy)silylisopentyl trimethoxycinnamate, and isopropyl paramethoxycinnamate / diisopropyl cinnamic acid ester mixtures; Benzoylmethane-based UV absorbers such as 4-isopropyldibenzoylmethane and 4-tert-butyl-4'-methoxydibenzoylmethane (e.g., "Parasol 1789" manufactured by DSM Nutrition Japan); Octocrylene (e.g., Parasol 340 from DSM Nutrition Japan), 2-ethylhexyl dimethoxybenzylidene dioxoimidazolidine propionate (e.g., Soft Shade DH from Ajinomoto Co., Inc.), 1-(3,4-dimethoxyphenyl)-4,4-dimethyl-1,3-pentanedione, cinoxate, methyl-O-aminobenzoate, 3-(4-methylbenzylidene)camphor, octyltriazone, diethylaminohydroxybenzoyl hexyl benzoate (2-(4-diethylamino-2-hydroxybenzoyl) hexyl benzoate ester, e.g., Ubinar from BASF) Examples include "Aplus" (a type of triazine), bisethylhexyloxyphenol methoxyphenyl triazine (2,4-bis{[4-(2-ethylhexyloxy)-2-hydroxy]phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine, e.g., BASF's "Tinosorb S"), methylenebisbenzotriazolyltetramethylbutylphenol (e.g., BASF's "Tinosorb M"), 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine (hereinafter also called "ethylhexyl triazone," e.g., BASF's "Ubinal T150"), etc.

[0070] As water-soluble organic ultraviolet absorbers, salicylic acid-based ultraviolet absorbers, cinnamic acid-based ultraviolet absorbers, benzoylmethane-based ultraviolet absorbers, and other organic ultraviolet absorbers with a solubility in water of more than 1 w / w% can be used. Examples include salicylic acid triethanolamine salt and p-methoxyhydrocinnamate diethanolamine salt.

[0071] Among the above, from the perspective of improving UV protection, the UV absorbers include 2-ethylhexyl paramethoxycinnamate, 4-tert-butyl-4'-methoxydibenzoylmethane, octocrylene, 2-ethylhexyl dimethoxybenzylidene dioxoimidazolidine propionate, diethylamino hydroxybenzoyl hexyl benzoate, bis-ethylhexyloxyphenol methoxyphenyl triazine, methylene bisbenzotriazolyltetramethylbutylphenol, and 2,4,6-tris[4-(2-ethylhexyloxyphenol] Preferably, one or more selected from the group consisting of [(2-(2-ethylhexyloxycarbonyl)anilino)]-1,3,5-triazine is used, more preferably one or more selected from the group consisting of 2-ethylhexyl paramethoxycinnamate, diethylamino hydroxybenzoyl hexyl benzoate, bis-ethylhexyloxyphenol methoxyphenyl triazine, and 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine, and even more preferably two or more of these are combined from the viewpoint of protecting against both UVA and UVB. Even more preferably, one or more selected from the group consisting of 2-ethylhexyl paramethoxycinnamate, diethylamino hydroxybenzoyl hexyl benzoate, and bis-ethylhexyloxyphenol methoxyphenyl triazine is used, and even more preferably two or more of these are combined.

[0072] When the topical skin preparation of the present invention contains an ultraviolet absorber, its content is preferably 0.2% by mass or more, more preferably 1.5% by mass or more, even more preferably 5% by mass or more, and even more preferably 7% by mass or more, from the viewpoint of improving the ultraviolet protection effect. Furthermore, from the viewpoint of improving the feel of the topical skin preparation, it is preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less, and even more preferably 15% by mass or less. The specific range of the ultraviolet absorber content in the topical skin preparation is preferably 0.2% by mass or more and 30% by mass or less, more preferably 1.5% by mass or more and 25% by mass or less, even more preferably 5% by mass or more and 20% by mass or less, and even more preferably 7% by mass or more and 15% by mass or less.

[0073] (UV scattering agent) The topical skin preparation of the present invention may further contain an ultraviolet scattering agent from the viewpoint of improving the ultraviolet protection effect. As an ultraviolet scattering agent, inorganic particles are preferred due to their high ultraviolet scattering effect, and metal oxide particles other than component (A), i.e., metal oxide particles other than spherical metal oxides (A1) and plate-like metal oxides (A2) with an average particle size of 350 nm to 2,500 nm, are more preferred. Examples of such metal oxides other than component (A) include titanium dioxide, zinc oxide, iron oxide, zirconium oxide, aluminum oxide, etc., and one or more selected from the group consisting of titanium dioxide and zinc oxide other than component (A) are even more preferred.

[0074] The inorganic particles used as ultraviolet scattering agents are preferably hydrophobized by surface treatment to improve their dispersibility in topical skin preparations. Surface treatment methods for hydrophobization include, for example, silicone treatment with methylhydrogenpolysiloxane (hydrogen dimethicone), methylpolysiloxane (dimethicone), methylhydrogenpolysiloxane-dimethylpolysiloxane copolymer, etc.; fluorine treatment with perfluoroalkyl phosphate ester, perfluoro alcohol, etc.; amino acid treatment with N-acyl glutamic acid, etc.; hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, octadecyltrimethoxysilane, octyltriethoxysilane Examples of surface treatments include: silane compound treatment with lan, trifluoropropyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, etc.; silazane treatment with hexamethyldisilazane, octyldisilazane, etc.; lecithin treatment; metal soap treatment; fatty acid treatment with caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, araginic acid, arachidonic acid, behenic acid, etc.; alkyl phosphate ester treatment; inorganic compound treatment with silica, alumina, aluminum hydroxide, etc. One or more of these surface treatment methods can be used.

[0075] The particle shape of the ultraviolet scattering agent can be spherical with an average particle size of less than 350 nm, or it can be rod-shaped, spindle-shaped, needle-shaped, or irregularly shaped, but it is not particularly limited as long as it has an ultraviolet scattering effect. The average particle size of the UV scattering agent is usually 1 nm or more, preferably 5 nm or more, more preferably 8 nm or more, and even more preferably 10 nm or more, from the viewpoint of improving the UV protection effect. Furthermore, from the viewpoint of suppressing white cast when applied to the skin, it is preferably less than 350 nm, more preferably 300 nm or less, even more preferably 100 nm or less, and even more preferably 60 nm or less. The above average particle size can be measured in the same way as the average particle size of component (A1).

[0076] Commercially available UV scattering agents can also be used. Examples of commercially available titanium dioxide particles used as UV scattering agents include "MT-100TV" (aluminum hydroxide, stearic acid treatment) and "MTY-110M3S" (aluminum hydroxide, silica, hydrogen dimethicone treatment) manufactured by Teika Co., Ltd.

[0077] Examples of commercially available zinc oxide particles used as ultraviolet scattering agents include "FINEX-50-LPTM" (dimethicone treated), "FINEX-25" (no surface treatment), and "FINEX-25LP" (dimethicone treated) from Sakai Chemical Industry Co., Ltd., and "MZ-300" (no surface treatment), "MZ-504R3M" (hydrogen dimethicone treated), "MZY-303S" (hydrodimethicone treated), "MZ-306X" (triethoxysilylethyl polydimethylsiloxyethylhexyl dimethicone treated), "MZ-200" (no surface treatment), "MZY-203S" (hydrogen dimethicone treated), "MZ-150" (no surface treatment), "MZY-153S" (hydrogen dimethicone treated), "MZ-505S", and "MZY-505S" from Teika Co., Ltd.

[0078] Ultraviolet scattering agents can be used individually or in combination of two or more. If the topical skin preparation of the present invention contains an ultraviolet scattering agent, the content thereof is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, from the viewpoint of improving the ultraviolet protection effect. Furthermore, from the viewpoint of suppressing white cast when applied to the skin, the content thereof is preferably 20% by mass or less, more preferably 18% by mass or less, and even more preferably 15% by mass or less.

[0079] <Application> The topical skin preparation of the present invention can be used as a topical skin preparation for protection against ultraviolet or infrared radiation, for suppressing skin temperature rise, or for suppressing fatigue. By applying the topical skin preparation of the present invention to the skin, the skin can be effectively protected even when exposed to light containing wavelengths in the ultraviolet to infrared region, such as ultraviolet rays, infrared rays, or sunlight. This suppresses photoaging of the skin and rise in skin temperature caused by exposure to ultraviolet rays, infrared rays, or sunlight, and also provides a heat-shielding effect on the skin. Furthermore, when animals such as humans engage in endurance exercise in a sunlight-irradiated environment, fatigue is more likely to occur if the amount of sunlight is high. However, by using the topical skin preparation of the present invention, such fatigue caused by sunlight irradiation can be suppressed.

[0080] The fatigue-reducing effect of topical skin preparations can be evaluated, for example, by the following method. The topical skin preparation was applied at a dose of 2 mg / cm² to the subject's exposed areas (face, chest, back, arms, back of hands, and feet). 2 The product is applied to the skin and allowed to dry for 15 minutes. Next, artificial sunlight sources are placed in front of, behind, and to the sides of the subject, and simulated sunlight is shone onto the subject's upper body. The subject then uses an ergometer (e.g., Monarch Standard Ergometer 828E) to maintain a constant heart rate while exercising for 30 minutes. The subject self-assessses their sensation of heat and fatigue during exercise, and the effect of using the topical skin agent on exercise performance is evaluated.

[0081] <Method for manufacturing topical skin preparations> The method for producing the topical skin preparation of the present invention is not particularly limited, and known methods can be used as appropriate depending on the dosage form of the topical skin preparation. For example, one method is to combine components (A), (B) and all other components and mix them uniformly using a disperser or the like. Alternatively, one method can be used in which all components except water and the aqueous medium are combined and mixed uniformly using a disperser or the like, and then water and the aqueous medium are added and further mixed by stirring with a homogenizer or the like. If the topical skin preparation is a water-in-oil emulsion composition or an oil-in-water emulsion composition, a method of preparing the aqueous phase and the oil phase separately and then mixing them can also be used.

[0082] [Methods for protecting the skin from infrared radiation] The present invention also provides a method for protecting the skin from infrared radiation, comprising the step of applying the topical skin preparation of the present invention to the skin. The infrared protection method of the present invention is not particularly limited as long as it includes a step of applying the topical skin preparation of the present invention to the skin. Methods of applying the topical skin preparation to the skin include application, spraying, etc.

[0083] In the infrared protection method of the present invention, the infrared protection rate at a wavelength of 825 nm is preferably 35% or more, more preferably 45% or more, and even more preferably 55% or more. Furthermore, when the infrared protection rate at a wavelength of 825 nm is 65% or more, the perceived heat shielding effect on the skin is particularly good. The infrared protection rate (%) can be measured specifically by the method described in the examples. [Examples]

[0084] The present invention will be described below with reference to examples, but the present invention is not limited to the scope of these examples. In these examples, various measurements and evaluations were performed by the following methods.

[0085] <Viscosity> The viscosity of each topical skin preparation at 25°C was measured the day after preparation using a Type B viscometer (TOKI SANGYO VISCOMETER TVB-10M, manufactured by Toki Sangyo Co., Ltd.) under the conditions of a rotor speed of 6.0 rpm and a rotation time of 60 seconds. Rotors No. 2 to No. 4 were used depending on the viscosity. [No. 2: viscosity 500-5000 mPa·s, No. 3: viscosity greater than 5000 mPa·s and less than or equal to 20000 mPa·s, No. 4: viscosity greater than 20000 mPa·s]

[0086] <Near infrared protection rate> 50.0 mg of each topical skin preparation was applied to a 5 cm x 5 cm polymethyl methacrylate (PMMA) substrate (SPF Matser PA-1, manufactured by Fuji Chemical Co., Ltd.), dried for 15 minutes, and used as a sample for measurement. Similarly, an uncoated PMMA substrate was used as a control sample. The transmittance at a wavelength of 825 nm was measured for both the measurement sample and the control sample using a near-infrared microscope. The transmittance of the measurement sample divided by the transmittance of the control sample was defined as transmittance X (%), and 100 - X (%) was defined as the near-infrared protection rate. A higher value indicates a higher near-infrared protection effect of the topical skin preparation itself.

[0087] Furthermore, the near-infrared protection effect was evaluated on a 5-point scale based on the following criteria. (Evaluation Criteria) 5: Near-infrared protection rate of 65.0% or higher 4: Near-infrared protection rate is 55.0% or more and less than 65.0% 3: Near-infrared protection rate is 45.0% or more and less than 55.0% 2: Near-infrared protection rate is 35.0% or more and less than 45.0% 1: Near-infrared protection rate is less than 35.0%

[0088] <Coating film uniformity> On a 5cm x 5cm polymethyl methacrylate (PMMA) substrate, 2 mg / cm² of each example of topical skin preparation was applied. 2 It was applied evenly and dried at 25°C for 15 minutes. For substrates coated with topical skin agents, the transmittance distribution at a wavelength of 825 nm was imaged using a near-infrared microscope (IR microscope). From this distribution image, the transmittance distribution of the ridges (convex parts of the PMMA plate) and grooves (concave parts of the PMMA plate) was examined, and their uniformity was evaluated on a 5-point scale, with 1 point indicating that "only the grooves were protected and the ridges were hardly protected" and 5 points indicating that "both the ridges and grooves were uniformly protected." (Evaluation Criteria) 1: Only the skin furrows are protected, and the skin ridges are hardly protected at all. 2: The skin furrows are protected, and the skin ridges are slightly protected. 3: The skin furrows are protected, and the skin ridges are protected to some extent. 4: The skin furrows are protected, and the skin ridges are well protected. 5: Both the skin furrows and ridges are uniformly protected.

[0089] <White cast when applied to the skin> Approximately 0.09g of each topical skin preparation was applied to a 3cm x 3cm area on the inside of a specialist panelist's forearm. The whiteness immediately after application was evaluated on a 5-point scale, with 1 point indicating very white and highly unnatural-looking whiteness, and 5 points indicating natural whiteness with no noticeable discomfort. Three specialist panelists performed the evaluation, and the average score was used as the evaluation result. (Evaluation Criteria) 1: It's very pale and looks very unnatural. 2: It's a bit too pale and looks unnatural. 3: Neither 4: It's a natural white, but it feels a little unnatural. 5: Natural whiteness, no unnatural feeling

[0090] <Effect of suppressing skin temperature rise> Approximately 3.2 g of the topical skin preparations from Example 6 and Comparative Example 5 were uniformly applied to an area of ​​approximately 4 cm x 4 cm on the inner forearm of a specialist panelist and dried for 15 minutes at 25°C and 40% RH. Subsequently, simulated sunlight was irradiated onto the applied area for 5 minutes from a distance of 24 cm using a solar simulator (HAL-320W, manufactured by Asahi Spectroscopic Co., Ltd.). A thermal camera (FLIR T-420) was used to measure skin temperature changes during irradiation. The temperature rise without topical skin preparation was also measured using the same method, and the result (temperature rise without topical skin preparation (°C)) - (temperature rise with topical skin preparation (°C)) is shown in the table. A larger value indicates a higher skin temperature rise suppression effect.

[0091] Examples 1-23, Comparative Examples 1-6 (Manufacturing and Evaluation of Topical Skin Preparations) All components except water from those shown in Tables 1-4 were combined and uniformly mixed in a disperser. Water was then added to the resulting mixture and uniformly mixed using a homogenizer to produce a water-in-oil type topical skin preparation with the composition shown in Tables 1-4. The obtained topical skin preparation was evaluated using the method described above. The results are shown in Tables 1-4. Note that the amounts listed in each table, except for "BENTONE GEL PTM V", represent the amount of active ingredient (mass%) for each component. The amount of "BENTONE GEL PTM V" is the mass% in its raw form. In the tables, metal oxides that do not correspond to component (A) are indicated as "Component (A1')".

[0092] [Table 1]

[0093] [Table 2]

[0094] [Table 3]

[0095] [Table 4]

[0096] Examples 24-27 (Manufacturing of topical skin preparations) For Examples 24 and 25, all components except water from the ingredients shown in Table 5 were combined and uniformly mixed in a disperser. Then, water was added to the resulting mixture and uniformly mixed using a homogenizer to produce a water-in-oil type solid topical skin preparation with the composition shown in Table 5. For Examples 26 and 27, all components shown in Table 5 were combined and uniformly mixed in a disperser to produce a solid topical skin preparation. The amounts listed in the table represent the amount of active ingredient (mass%) of each component.

[0097] [Table 5]

[0098] The ingredients listed in the table are as follows: *1: "R-38L" manufactured by Sakai Chemical Industry Co., Ltd., ZrO2-Al2O3 coated spherical titanium oxide, average particle size 400 nm *2: "ST-750EC" manufactured by Titanium Industries Co., Ltd., spherical titanium oxide coated with aluminum hydroxide-hydrogen dimethicone, average particle size 1,000 nm *3: "LP-ZINC-2KS" manufactured by Sakai Chemical Industry Co., Ltd., hydrogen dimethicone coated spherical zinc oxide, average particle size 2,000 nm *4: "JR800s" manufactured by Teika Co., Ltd., hydrogen dimethicone coated spherical titanium dioxide, average particle size 270 nm *5: Surface ASC treated plate-shaped titanium oxide (CQV's "Featheleve PT-7801K") manufactured by Daito Chemical Industries, Ltd., thickness 134nm, aspect ratio 95 *6: Surface ASC treated plate-shaped titanium oxide (CQV's "Featheleve PT-7401K") manufactured by Daito Chemical Industries, Ltd., thickness 112nm, aspect ratio 126 *7: Surface ASC treated plate-shaped titanium oxide (CQV's "Featheleve PT-7901K") manufactured by Daito Chemical Industries, Ltd., thickness 191nm, aspect ratio 58 *8: "XZ-1000F-LP" manufactured by Sakai Chemical Industry Co., Ltd., hydrogen dimethicone coated plate-shaped zinc oxide, thickness 290 nm, aspect ratio 3.4 *9: Kao Corporation's "Excepearl IPP", isopropyl palmitate *10: KF-96L-10cs, manufactured by Shin-Etsu Chemical Co., Ltd., dimethicone, viscosity 10 mPa·s *11: BENTONE GEL PTM V manufactured by Elementis, containing caprylic / capric triglyceride, stearalkonium hectorite, and propylene carbonate, with 96.8% by mass of non-volatile components (measured value). *12: "Leopal KL2" manufactured by Chiba Flour Milling Co., Ltd., dextrin palmitate *13: DOWSIL AMS-C30 COSMETIC WAX, manufactured by Dow Toray Industries, Ltd., alkyl (C30-45) methicone *14: "Silicone KF-6028" manufactured by Shin-Etsu Chemical Co., Ltd., PEG-9 polydimethylsiloxyethyl dimethicone *15: Kao Corporation's "OS-88E-TV-E," N-propionyl polyethyleneimine / methylpolysiloxane copolymer (30% by mass - ethanol solution) *16: "EB-21" manufactured by Ajinomoto Co., Inc., dibutylethylhexanoyl glutamide *17: HNP-9, manufactured by Nippon Seiro Co., Ltd., paraffin wax, melting point: 80℃ *18: Ceresin #810K, manufactured by Nikko Rica Co., Ltd., Ceresin, Melting point: 74℃

[0099] Tables 1-4 show that the topical skin preparation of this embodiment has high infrared protection effect, high film uniformity, and minimal white cast when applied to the skin. It also exhibits excellent skin temperature rise suppression effects.

[0100] Figure 1 shows an IR microscope image (score 5) of the uniformity of the skin coating of Example 9, and Figure 2 shows an IR microscope image (score 1) of the uniformity of the skin coating of Comparative Example 2. In Figures 1 and 2, white areas indicate the presence of component (A), and black areas indicate the absence of component (A). When the skin coating of Example 9 was applied, component (A) was abundant not only in the skin furrows but also in the skin ridges (Figure 1), whereas when the skin coating of Comparative Example 2 was applied, most of the component (A) fell into the skin furrows, indicating low uniformity of the coating (Figure 2). [Industrial applicability]

[0101] According to the present invention, it is possible to provide a topical skin preparation that has excellent protective effects against ultraviolet rays, infrared rays, etc., and leaves little white residue when applied to the skin. When this topical skin preparation is applied to the skin, it can protect the skin from ultraviolet rays, infrared rays, etc., and furthermore, it can also provide effects of suppressing the rise in skin temperature caused by sunlight irradiation and suppressing fatigue.

Claims

1. Component (A): one or more metal oxides selected from the group consisting of spherical metal oxides (A1) and plate-like metal oxides (A2) having an average particle size of 350 nm to 2,500 nm, and Component (B): non-volatile oil, A skin topical preparation comprising The content of component (A) in the topical skin preparation is 2% by mass or more and 50% by mass or less, The viscosity at 25°C is 2,500 mPa·s or more. Skin topical agent.

2. The topical skin preparation according to claim 1, wherein the viscosity (mPa·s) of the topical skin preparation relative to the content (mass %) of the component (A) in the topical skin preparation is 100 or more.

3. The topical skin preparation according to claim 1 , wherein the content of said component (A) in the non-volatile components of said topical skin preparation is 50% by mass or less.

4. The skin topical preparation according to claim 1 , wherein the component (A) contains plate-like titanium oxide as component (A2).

5. 5. The external preparation for skin according to claim 4, wherein the content of said plate-like titanium oxide in said external preparation for skin is 5% by mass or more and 30% by mass or less.

6. The skin topical preparation according to claim 1, wherein the thickness of the component (A2) is 30 nm or more and 360 nm or less.

7. The external skin preparation according to claim 1 , wherein the aspect ratio of the component (A2) is 3 or more and 300 or less.

8. The topical skin preparation according to claim 1, wherein the component (A) contains, as component (A1), a spherical metal oxide having an average particle size of 700 nm or more and 2,500 nm or less, and has a viscosity at 25°C of 2,500 mPa·s or more and 20,000 mPa·s or less.

9. 2. The skin topical preparation according to claim 1, wherein the component (B) is at least one selected from the group consisting of ester oils, silicone oils, hydrocarbon oils, higher fatty acids, and higher alcohols.

10. The external skin preparation according to claim 1 , further comprising a thickener.

11. The external skin preparation according to claim 10, wherein the thickener is an oil thickener.

12. The skin external preparation according to claim 11, wherein the oil thickener is at least one selected from the group consisting of solid waxes, organically modified clay minerals, dextrin fatty acid esters, and amino acid gelling agents.

13. The external skin preparation according to claim 10, wherein the content of the thickener in the external skin preparation is 0.5% by mass or more and 50% by mass or less.

14. The topical skin preparation according to claim 1 , further comprising water.

15. The topical skin preparation according to claim 1 , wherein the topical skin preparation is in a solid form.

16. 2. The external skin preparation according to claim 1, which is an external skin preparation for protection from ultraviolet or infrared rays, for suppressing an increase in skin temperature, or for suppressing fatigue.

17. A method for protecting the skin from infrared radiation, comprising the step of applying the external skin preparation according to any one of claims 1 to 16 to the skin.

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