JP7572778B2 - Skin preparations - Google Patents

Description

The present invention relates to a skin topical preparation and a method for protecting the skin from infrared and ultraviolet rays.

From the viewpoint of protecting the skin against sunlight, ultraviolet ray protective cosmetics such as sunscreen cosmetics are known. On the other hand, due to the recent increase in health consciousness, there is a demand for external skin preparations having a protective function against infrared rays.
Regarding skin external preparations having infrared protection function, for example, Patent Document 1 discloses a preventive agent for near-infrared damage to biological tissues, which contains an infrared transmission shielding agent consisting of titanium oxide powder and zinc oxide powder, as a technology relating to a preventive agent that prevents infrared rays from reaching tissues deeper than the skin tissue and prevents damage to those tissues by infrared rays. Patent Document 2 discloses a near-infrared protective cosmetic composition consisting of titanium oxide powder and zinc oxide powder, which combines excellent near-infrared protection effect and high transparency.

International Publication No. 2009/017104 JP 2017-95361 A

However, for the purpose of skin protection, there is a demand for skin preparations for external use that further improve the infrared protection function and also have excellent ultraviolet protection effects. Furthermore, among skin preparations for external use, skin cosmetics are required to have a natural appearance without turning white when applied to the skin, to have good makeup application after application, to be less sticky, and to have an excellent feel when used.
To provide an external preparation for skin which has excellent infrared protection effect and ultraviolet protection effect, is unlikely to whiten the skin when applied to the skin, has a natural appearance, provides good makeup application after application, is less sticky and has an excellent feeling when used, and provides a method for protecting the skin from infrared and ultraviolet rays.

The present inventors have discovered that the above-mentioned problems can be solved by an external skin preparation containing a metal oxide of a specific shape and an ultraviolet absorbing agent in a specific ratio.
That is, the present invention relates to the following [1] and [2].
[1] A skin topical preparation comprising a plate-like metal oxide (A) having a thickness of 30 nm or more and 360 nm or less, and an ultraviolet absorber (B), wherein the mass ratio [(A)/(B)] is 0.1 or more and 5 or less.
[2] A method for protecting the skin from infrared rays and ultraviolet rays, comprising applying the topical skin preparation described in [1] above to the skin.

The skin topical preparation of the present invention has excellent infrared and ultraviolet protection effects, does not turn white when applied to the skin, has a natural appearance, provides good makeup application after application, is less sticky, and has an excellent feel when used, making it useful, for example, as a skin cosmetic.

[External skin preparations]
The topical skin preparation of the present invention contains a plate-like metal oxide (A) having a thickness of 30 nm or more and 360 nm or less and an aspect ratio of 50 or more and 300 or less, and an ultraviolet absorber (B), and the mass ratio [(A)/(B)] is 0.1 or more and 5 or less.

In the present invention, the thickness of the plate-like metal oxide particle means the length of the shortest axis of the plate-like metal oxide particle.
In the present invention, ultraviolet light means electromagnetic waves having a wavelength of 290 to 400 nm.
In the present invention, infrared rays refer to electromagnetic waves with wavelengths of 780 nm to 1 mm. The skin topical preparation of the present invention is particularly effective in protecting against near-infrared rays with wavelengths of 780 nm to 2500 nm. This prevents the skin temperature from rising due to exposure to sunlight, providing a strong sense of heat insulation.
In this specification, the infrared protection effect is indicated by the infrared protection rate at a wavelength of 1500 nm, and the ultraviolet protection effect is indicated by the SPF (Sun Protection Factor) value (protection effect against ultraviolet B rays (UVB)).

The formulation of the topical skin preparation of the present invention is not particularly limited, but from the viewpoint of ease of application to the skin, it is preferable that the topical skin preparation is in the form of a liquid, gel, or cream. The topical skin preparation may be in the form of an emulsion composition, and the emulsion composition may be either an oil-in-water emulsion composition or a water-in-oil emulsion composition.
The skin topical preparation of the present invention is preferably a skin cosmetic such as a sunscreen cosmetic (skin lotion, cream, milky lotion, serum, etc.), a suntan, or a makeup base cosmetic.

<Plate-shaped metal oxide (A)>
The external skin preparation of the present invention contains a plate-like metal oxide (A) having a thickness of 30 nm or more and 360 nm or less and an aspect ratio of 50 or more and 300 or less.
The skin topical preparation of the present invention contains a plate-like metal oxide having a predetermined thickness as component (A), and therefore has excellent infrared protection effect, provides a high heat shielding effect, and is less likely to turn white when applied to the skin, resulting in a natural appearance.Furthermore, it is possible to prevent stickiness when applied to the skin.

It is known that in skin topical preparations containing inorganic particles such as titanium oxide, the use of particles with a larger particle size provides a higher infrared protection effect. However, there is a limit to the improvement of infrared protection effect simply by using inorganic particles with a large particle size. In addition, for example, when spherical inorganic particles with a particle size larger than the wavelength of visible light are blended into a skin topical preparation, there is a drawback in that when applied to the skin, visible light is scattered on the particle surface, so the product tends to turn white, resulting in a less natural appearance. Therefore, it has been difficult to achieve both infrared protection effect and a natural appearance when applied to the skin simply by controlling the particle size of the inorganic particles used.

The inventors have discovered that by using a plate-like metal oxide of a specified thickness as component (A) in an external skin preparation, it is possible to selectively increase the reflectance of light in the infrared region while reducing the reflectance of light in the visible region through the optical interference effect, thereby achieving both an infrared protection effect and a natural appearance when applied to the skin.
When the thickness of component (A) is within the above-mentioned range (30 nm or more and 360 nm or less), when an external preparation containing component (A) is applied to the skin, the reflectance of light observed on the upper surface of the skin becomes high for light with wavelengths in the infrared region due to the optical interference effect, and low for light with wavelengths in the visible region. Therefore, the external preparation for skin of the present invention can achieve both a high infrared protection effect and a natural appearance when applied to the skin.
The use of the above-mentioned component (A) improves the application of makeup. Furthermore, the combined use of component (A) and component (B) synergistically enhances the ultraviolet protection effect.

From the viewpoint of obtaining excellent infrared protection effect and ultraviolet protection effect by the above-mentioned mechanism of action, and from the viewpoint of natural appearance when applied to the skin, the thickness of component (A) is 30 nm or more, preferably 50 nm or more, more preferably 60 nm or more, more preferably 80 nm or more, even more preferably 105 nm or more, and even more preferably 125 nm or more. Also, from the viewpoint of obtaining excellent infrared protection effect and ultraviolet protection effect, and from the viewpoint of natural appearance when applied to the skin and makeup wear after application, the thickness of component (A) is 360 nm or less, preferably 330 nm or less, 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, and even more preferably 150 nm or less. A specific range of the thickness of component (A), from the viewpoint of obtaining excellent infrared protection effect and ultraviolet protection effect, and from the viewpoint of a natural appearance when applied to the skin and the makeup application after application, is 30 nm or more and 360 nm or less, preferably 50 nm or more and 330 nm or less, more preferably 60 nm or more and 310 nm or less, even more preferably 60 nm or more and 280 nm or less, still more preferably 80 nm or more and 280 nm or less, still more preferably 105 nm or more and 270 nm or less, still more preferably 125 nm or more and 230 nm or less, and still more preferably 125 nm or more and 150 nm or less.
The thickness of component (A) can be determined from an image observed by a scanning electron microscope (SEM). Specifically, component (A) is observed by SEM at a magnification of 10,000 times, the thicknesses of 50 particles in the observed image are measured, and the average thickness per particle is calculated. Specifically, the thickness of component (A) can be measured by the method described in the examples.

From the viewpoint of obtaining excellent infrared protection effect and ultraviolet protection effect, and from the viewpoint of a natural appearance when applied to the skin and makeup application after application, the aspect ratio of component (A) is 50 or more, preferably 55 or more, more preferably 65 or more, even more preferably 70 or more, and still more preferably 100 or more. From the viewpoint of obtaining excellent infrared protection effect and ultraviolet protection effect, and from the viewpoint of a natural appearance when applied to the skin, the aspect ratio is 300 or less, preferably 230 or less, more preferably 200 or less, even more preferably 140 or less, still more preferably 125 or less, and still more preferably 120 or less. A specific range of the aspect ratio of component (A), from the viewpoint of obtaining excellent infrared protection effect and ultraviolet protection effect, and from the viewpoint of a natural appearance when applied to the skin and the makeup application after application, is from 50 to 300, preferably from 50 to 230, more preferably from 55 to 230, even more preferably from 55 to 200, still more preferably from 55 to 140, still more preferably from 55 to 125, still more preferably from 65 to 125, still more preferably from 70 to 120, and still more preferably from 100 to 125.
The aspect ratio of component (A) is determined by performing SEM observation under the same conditions as 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 averaging the calculated values. The aspect ratio of the plate-like metal oxide can be specifically measured by the method described in the Examples.

The metal oxide constituting component (A) is preferably a high refractive index material, which provides a higher light interference effect. From this viewpoint, preferred metal oxides constituting component (A) include titanium oxide, zinc oxide, zirconium oxide, iron oxide, aluminum oxide, cerium oxide, and the like. Among these, preferred are at least one selected from the group consisting of titanium oxide and zinc oxide, more preferred is titanium oxide. That is, component (A) is preferably at least one selected from the group consisting of plate-like titanium oxide and plate-like zinc oxide, more preferred is plate-like titanium oxide.
The crystal structure of titanium oxide may be any of rutile, anatase, and amorphous, but from the viewpoint of obtaining excellent infrared protection effect and heat shielding feeling, the rutile type is preferred.

The plate-like metal oxide of component (A) may not be surface-treated, or may be surface-treated, such as hydrophobized, by a known method as necessary to enhance dispersibility in the topical skin preparation. The plate-like metal oxide of component (A) is to be distinguished from particles other than metal oxides whose surfaces have been surface-treated with metal oxides.

Examples of the surface treatment agent used for the surface treatment of component (A) include silicones, alkylalkoxysilanes, fluorine-containing compounds such as perfluoroalkyl phosphates and perfluoroalcohols, amino acids such as N-acylglutamic acid, and others, lecithin, metal soaps, fatty acids such as stearic acid, alkyl phosphates, etc. Among these, from the viewpoint of improving the dispersibility of component (A) in topical preparations, one or more selected from the group consisting of silicones and alkylalkoxysilanes are preferred.
The silicone as the surface treatment agent is not particularly limited, and examples thereof include various silicone oils such as methylpolysiloxane, dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, 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.
As the alkylalkoxysilane used as the surface treatment agent, those having a branched or linear alkyl group having 6 to 20 carbon atoms are preferred, and in particular, octyltriethoxysilane and octyltrimethoxysilane can be mentioned.
From the viewpoint of improving the infrared protection effect, one or more members selected from the group consisting of methylpolysiloxane, dimethylpolysiloxane, methylhydrogenpolysiloxane, (alkyl acrylate/dimethicone) copolymer, and octyltriethoxysilane are preferred.
When component (A) is surface-treated, the amount of coating with 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, based on the total amount of the plate-like metal oxide of component (A), from the viewpoint of improving dispersibility in the topical skin preparation.

The content of component (A) in the skin topical preparation is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 6% by mass or more, and even more preferably 8% by mass or more, from the viewpoint of obtaining excellent infrared protection effect, ultraviolet protection effect, natural appearance when applied to the skin, and makeup application after application. Also, from the viewpoint of natural appearance when applied to the skin, and makeup application after application, the content of component (A) in the skin topical preparation is preferably 35% by mass or less, more preferably 25% by mass or less, even more preferably 17% by mass or less, and even more preferably 12% by mass or less.
The specific range of the content of component (A) in the topical skin preparation, from the viewpoint of achieving both infrared protection effect and ultraviolet protection effect, a natural appearance when applied to the skin, and good makeup application after application, is preferably from 1% by mass to 35% by mass, more preferably from 3% by mass to 25% by mass, even more preferably from 6% by mass to 17% by mass, and still more preferably from 8% by mass to 12% by mass.

As component (A), commercially available plate-like metal oxides can also be used. For example, commercially available plate-like titanium oxides include "Featheleve PT-9001K", "Featheleve PT-7001K", "Featheleve PT-7401K", "Featheleve PT-7801K", and "Featheleve PT-7901K" manufactured by CQV Corporation.

<Ultraviolet absorber (B)>
The external skin preparation of the present invention contains an ultraviolet absorbing agent as component (B) from the viewpoint of obtaining an ultraviolet protection effect.
Component (B) is preferably an organic UV absorber, and an oil-soluble organic UV absorber or a water-soluble organic UV absorber can be used. From the viewpoints of UV protection effect, natural appearance when applied to the skin, good makeup application after application, and suppression of stickiness, component (B) is preferably an oil-soluble organic UV absorber. Note that "oil-soluble" means that the solubility in water is 1 w/w% or less.
From the viewpoint of obtaining the effects of the present invention, component (B) is distinguished from inorganic ultraviolet absorbents such as ultraviolet absorbents in which the surface of an inorganic filler is coated with an ultraviolet absorbing material.

As the oil-soluble organic ultraviolet absorber, salicylic acid-based ultraviolet absorbers, cinnamic acid-based ultraviolet absorbers, benzoylmethane-based ultraviolet absorbers, and other organic ultraviolet absorbers that are oil-soluble can be used.
For example, salicylic acid-based ultraviolet absorbers such as homomenthyl salicylate and octyl salicylate;
cinnamic acid-based ultraviolet absorbers such as 2-ethylhexyl paramethoxycinnamate (for example, "Uvinal MC80" manufactured by BASF), glyceryl di-paramethoxycinnamate mono-2-ethylhexanoate, methyl 2,5-diisopropylcinnamate, bis(trimethylsiloxy)silylisopentyl methyl trimethoxycinnamate, and a mixture of isopropyl paramethoxycinnamate and diisopropyl cinnamate;
Benzoylmethane-based ultraviolet absorbers such as 4-isopropyldibenzoylmethane and 4-tert-butyl-4'-methoxydibenzoylmethane (for example, "Parasol 1789" manufactured by DSM Nutrition Japan);
Octocrylene (e.g., "Parasol 340" manufactured by DSM Nutrition Japan Co., Ltd.), 2-ethylhexyl dimethoxybenzylidene dioxoimidazolidinepropionate (e.g., "Soft Shade DH" manufactured by Ajinomoto Co., Inc.), 1-(3,4-dimethoxyphenyl)-4,4-dimethyl-1,3-pentanedione, cinoxate, methyl-O-aminobenzoate, 3-(4-methylbenzylidene)camphor, octyl triazone, diethylaminohydroxybenzoyl hexyl benzoate (2-(4-diethylamino-2-hydroxybenzoyl)benzoic acid hexyl ester, e.g., "Ubinar" manufactured by BASF Co., Ltd.), Examples of such compounds include "Tinosorb S" manufactured by BASF, bisethylhexyloxyphenol methoxyphenyl triazine (2,4-bis{[4-(2-ethylhexyloxy)-2-hydroxy]phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine, for example, "Tinosorb S" manufactured by BASF), methylene bisbenzotriazolyl tetramethylbutylphenol (for example, "Tinosorb M" manufactured by BASF), 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine (hereinafter also referred to as "ethylhexyl triazone", for example, "Uvinal T150" manufactured by BASF); and the like.

Examples of water-soluble organic UV absorbers that can be used include salicylic acid UV absorbers, cinnamic acid UV absorbers, benzoylmethane UV absorbers, and other organic UV absorbers that have a solubility in water of more than 1 w/w%, such as triethanolamine salicylate and diethanolamine p-methoxyhydrocinnamate.

Among the above, from the viewpoint of ultraviolet protection effect, examples of ultraviolet absorbers (B) include 2-ethylhexyl paramethoxycinnamate, 4-tert-butyl-4'-methoxydibenzoylmethane, octocrylene, 2-ethylhexyl dimethoxybenzylidene dioxoimidazolidinepropionate, diethylaminohydroxybenzoylhexyl benzoate, bisethylhexyloxyphenol methoxyphenyl triazine, methylene bisbenzotriazolyl tetramethylbutylphenol, and 2,4,6-tris[4-(2-ethylhexyloxy)phenyl]phenyl. Preferably, the compound is at least one selected from the group consisting of 2-ethylhexyl paramethoxycinnamate, diethylamino hydroxybenzoyl hexyl benzoate, bisethylhexyloxyphenol methoxyphenyl triazine, and 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine, more preferably at least one selected from the group consisting of 2-ethylhexyl paramethoxycinnamate, diethylamino hydroxybenzoyl hexyl benzoate, and bisethylhexyloxyphenol methoxyphenyl triazine, and even more preferably at least two of these compounds are combined from the viewpoint of protecting against both UVA and UVB. Even more preferably, the compound is at least one selected from the group consisting of 2-ethylhexyl paramethoxycinnamate, diethylamino hydroxybenzoyl hexyl benzoate, and bisethylhexyloxyphenol methoxyphenyl triazine, and even more preferably at least two of these compounds are combined.

The mass ratio of component (A) to component (B) in the topical skin preparation of the present invention [(A)/(B)] is preferably 0.1 or more, more preferably 0.3 or more, even more preferably 0.55 or more, and even more preferably 0.7 or more, from the viewpoint of obtaining an excellent infrared protection effect and ultraviolet protection effect, a natural appearance when applied to the skin, and makeup application after application. Also, from the viewpoint of obtaining an excellent ultraviolet protection effect, a natural appearance when applied to the skin, and makeup application after application, it is preferably 5 or less, more preferably 3.5 or less, even more preferably 2.3 or less, even more preferably 1.5 or less, and even more preferably 1.2 or less. The specific range of the mass ratio [(A)/(B)] of component (A) to component (B) in the skin topical preparation is from 0.1 to 5, preferably from 0.3 to 3.5, more preferably from 0.3 to 3.5, even more preferably from 0.3 to 2.3, even more preferably from 0.55 to 1.5, even more preferably from 0.55 to 1.2, and even more preferably from 0.7 to 1.2, from the viewpoint of achieving both infrared protection effect and ultraviolet protection effect, a natural appearance when applied to the skin, and makeup application after application.

The content of component (B) in the skin topical preparation of the present invention is not particularly limited as long as the mass ratio [(A)/(B)] is 0.1 or more and 5 or less, but from the viewpoint of obtaining excellent infrared protection effect and ultraviolet protection effect, and from the viewpoint of makeup application after application, it is preferably 0.2 mass% or more, more preferably 1.5 mass% or more, even more preferably 5 mass% or more, and even more preferably 7 mass% or more. Also, from the viewpoint of obtaining excellent infrared protection effect and makeup application after application, it is preferably 30 mass% or less, more preferably 25 mass% or less, even more preferably 20 mass% or less, and even more preferably 15 mass% or less. The specific range of the content of component (B) in the skin topical preparation is preferably 0.2 mass% or more and 30 mass% or less, more preferably 1.5 mass% or more and 25 mass% or less, even more preferably 5 mass% or more and 20 mass% or less, and even more preferably 7 mass% or more and 15 mass% or less, from the viewpoint of obtaining both infrared protection effect, makeup application after application, and ultraviolet protection effect.

In addition, from the viewpoint of obtaining excellent infrared protection effect and ultraviolet protection effect, the total content of component (A) and component (B) in the topical skin preparation is preferably 1.2% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and even more preferably 15% by mass or more, with the upper limit being 100% by mass. In terms of the natural appearance when applied to the skin, the makeup spread after application, and reducing the squeaky feeling, the total content of component (A) and component (B) in the topical skin preparation is preferably 80% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less.

(Non-volatile oil (C))
The skin topical preparation of the present invention preferably further contains a non-volatile oil (C) from the viewpoint of the solubility of component (B) when an oil-soluble ultraviolet absorbent is used as component (B). The non-volatile oil refers to an oil agent other than the ultraviolet absorbent (B) described above, which evaporates less than 20% at 25°C for 6 hours as measured by the following method (1).
Method (1): Place a 90 mm diameter filter paper in a 120 mm diameter glass petri dish, place 1 g of sample on the filter paper, and store in a room (25°C) at 65% RH. After 6 hours, measure the residue of the sample and calculate the amount of evaporation.

Also, component (C) is preferably liquid at 1 atmosphere and 25° C. More specifically, component (C) 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, still more preferably 50 mPa·s or less, and preferably 5 mPa·s or more.
The viscosity can be measured using a Brookfield viscometer "TVB-10" (manufactured by Toki Sangyo Co., Ltd.) under conditions of rotor No. 1, 25°C, 60 rpm, and 1 minute.

Specific examples of component (C) include non-volatile oils other than component (B) that are liquid at 25°C, such as ester oils, silicone oils, hydrocarbon oils, higher fatty acids, and higher alcohols.

Examples of non-volatile liquid ester oils include isononyl isononanoate, isotridecyl isononanoate, isopropyl myristate, isocetyl myristate, octyldodecyl myristate, isopropyl palmitate, ethylhexyl palmitate, 2-hexyldecyl palmitate, glyceryl tri-2-ethylhexanoate, di-2-ethylhexyl sebacate, diisopropyl sebacate, glyceryl tri(caprylic acid/capric acid), diisostearyl malate, diethylene glycol dicaprate, neopentyl glycol dicaprate, neopentyl glycol di-2-ethylhexanoate, and one or more selected from the group consisting of alkyl benzoates such as alkyl benzoates (C12 to C15).

Among the above, from the viewpoints of a natural appearance when applied to the skin, makeup application after application, and suppression of stickiness, 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, alkyl benzoates (C12-C15) (e.g., Finsorb TN; Innospec Active Chemicals) (manufactured by Epson Corporation, LLC) are preferred, specifically, 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 benzoate (C12-C15) are more preferred, and isopropyl palmitate and alkyl benzoate (C12-C15) are even more preferred.

As a non-volatile liquid silicone oil, methylpolysiloxane is preferred from the viewpoint of suppressing stickiness when applied to the skin, and methylpolysiloxane with a viscosity of 20 mPa·s or less at 25°C is more preferred.

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, isohexadecane, etc. Among these, from the viewpoint of suppressing stickiness when applied to the skin, one or more types selected from the group consisting of light liquid isoparaffin and isohexadecane are preferred, and light liquid isoparaffin is more preferred.

Examples of non-volatile liquid higher fatty acids include fatty acids having 12 to 22 carbon atoms, and specific examples thereof include oleic acid, isostearic acid, linoleic acid, and linolenic acid.
Examples of non-volatile liquid higher alcohols include alcohols having 12 to 28 carbon atoms, and specific examples thereof include oleyl alcohol, 2-decyltetradecyl alcohol, dodecanol, isostearyl alcohol, and octyldodecanol.

Component (C) is preferably one or more selected from the group consisting of ester oils, silicone oils, and hydrocarbon oils, among non-volatile oils that are liquid at 25°C, from the viewpoint of suppressing stickiness when applied to the skin, more preferably one or more selected from the group consisting of ester oils and hydrocarbon oils, and even more preferably one or more selected from the group consisting of alkyl benzoates (C12-15), isopropyl palmitate, and light liquid isoparaffin.

When the skin topical preparation of the present invention contains component (C), the content is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 15% by mass or more, from the viewpoint of obtaining excellent infrared protection effect and ultraviolet protection effect, a natural appearance when applied to the skin, and makeup application after application, and from the viewpoint of the makeup application after application, the content is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 25% by mass or less. The specific range of the content of component (C) in the skin topical preparation is preferably 1% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 35% by mass or less, and even more preferably 15% by mass or more and 25% by mass or less, from the viewpoint of obtaining excellent infrared protection effect and ultraviolet protection effect, and from the viewpoint of achieving both a natural appearance when applied to the skin and makeup application after application.

When the topical skin preparation of the present invention contains component (C), the mass ratio [(A)/(C)] is, from the viewpoints of obtaining excellent infrared protection effect and ultraviolet protection effect, the natural appearance when applied to the skin, and the ease of application of makeup after application, preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.35 or more, and even more preferably 0.4 or more; and from the viewpoints of the natural appearance when applied to the skin and the ease of application of makeup after application, preferably 5 or less, more preferably 3 or less, even more preferably 2 or less, even more preferably 1.3 or less, even more preferably 0.75 or less, and even more preferably 0.6 or less. The specific range of the mass ratio [(A)/(C)] in the topical skin preparation is preferably 0.1 to 5, more preferably 0.1 to 3, even more preferably 0.2 to 2, still more preferably 0.2 to 1.3, even more preferably 0.35 to 0.75, and even more preferably 0.4 to 0.6, from the viewpoint of obtaining excellent infrared protection effect and ultraviolet protection effect, and from the viewpoint of achieving both a natural appearance when applied to the skin and good makeup application after application.

When the skin topical preparation of the present invention contains component (C), the mass ratio [(B)/(C)] is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, and even more preferably 0.45 or more, from the viewpoint of obtaining excellent infrared protection effect and ultraviolet protection effect, and from the viewpoint of makeup application after application, and is preferably 4 or less, more preferably 2 or less, even more preferably 1.5 or less, and even more preferably 0.75 or less, from the viewpoint of natural appearance when applied to the skin and makeup application after application. The specific range of the mass ratio [(B)/(C)] in the skin topical preparation is preferably 0.1 or more and 4 or less, more preferably 0.2 or more and 2 or less, even more preferably 0.3 or more and 1.5 or less, even more preferably 0.45 or more and 1.5 or less, even more preferably 0.45 or more and 0.75 or less, from the viewpoint of achieving both excellent infrared protection effect and ultraviolet protection effect, natural appearance when applied to the skin, and makeup application after application.

(Volatile Oil (C)')
The skin topical preparation of the present invention may further contain a volatile oil as component (C)'. The volatile oil refers to an oil agent other than the above-mentioned ultraviolet absorbent (B) that evaporates at 25°C for 6 hours in an amount of 20% or more as measured by the following method (1).
Method (1): Place a 90 mm diameter filter paper in a 120 mm diameter glass petri dish, place 1 g of sample on the filter paper, and store in a room (25°C) at 65% RH. After 6 hours, measure the residue of the sample and calculate the amount of evaporation.

Component (C)' is preferably a volatile silicone oil, and more preferably a linear organopolysiloxane or a cyclic organopolysiloxane that is liquid at 25°C and volatile.
Specific examples of linear organopolysiloxanes include octamethyltrisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane, and 1,1,1,3,5,5,5-heptamethyl-3-[(trimethylsilyl)oxy]-trisiloxane.
Examples of the cyclic organopolysiloxane include 4- to 6-membered cyclic siloxanes having an alkyl group having 1 to 5 carbon atoms as a substituent, and specific examples include octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane.

Among the above, cyclic organopolysiloxanes are preferred as component (C)' from the viewpoint of less stickiness when applied to the skin, and decamethylcyclopentasiloxane is more preferred.

Commercially available volatile silicone oils that can be used as component (C)' include "KF-96A-1cs" (octamethyltrisiloxane), "KF-96L-1.5cs" (decamethyltetrasiloxane), "KF-96L-2cs" (dodecamethylpentasiloxane), "KF-995" (decamethylcyclopentasiloxane), and "TMF-1.5" (1,1,1,3,5,5,5-heptamethyl-3-[(trimethylsilyl)oxy]-trisiloxane) manufactured by Shin-Etsu Chemical Co., Ltd., and "SH200C Fluid 1cs" (octamethyltrisiloxane), "SH200C Fluid 1.5cs" (decamethyltetrasiloxane), and "SH200C Fluid 2.5cs" (decamethyltetrasiloxane), manufactured by Dow Corning Toray Co., Ltd. 2cs" (dodecamethylpentasiloxane), "SH245 Fluid" (decamethylcyclopentasiloxane), and "TSF405" (decamethylcyclopentasiloxane) manufactured by Momentive Performance Materials.

When the topical skin preparation of the present invention contains component (C)', the content is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, preferably 75% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less, from the viewpoint of obtaining excellent infrared protection effect and ultraviolet protection effect, and from the viewpoint of natural appearance when applied to the skin, makeup application after application, and stickiness suppression effect. The specific range of the content of component (C)' in the topical skin preparation is preferably 10% by mass or more and 75% by mass or less, more preferably 20% by mass or more and 70% by mass or less, and even more preferably 25% by mass or more and 60% by mass or less.

(Surfactant (D))
It is preferable that the topical skin preparation of the present invention further contains a surfactant (D) from the viewpoint of achieving both an infrared protection effect and a natural appearance when applied to the skin, and from the viewpoint of dispersing an oily component in water or dispersing a water-soluble component in oil.
As the component (D), a known surfactant, such as an anionic surfactant, a cationic surfactant, an amphoteric surfactant, or a nonionic surfactant, can be used. In addition, a fluorine-based surfactant or a silicone-based surfactant can also be used.
From the viewpoint of achieving both an infrared protection effect and a natural appearance when applied to the skin, and from the viewpoint of dispersing oily components in water or water-soluble components in oil, the topical skin preparation of the present invention preferably contains at least a silicone-based surfactant, and more preferably contains a nonionic silicone-based surfactant.

Examples of silicone surfactants include polyether-modified silicones represented by the following general formulas (1) to (3).

[In the formula, R ¹ represents an alkyl group having 1 to 5 carbon atoms or a phenyl group, R ² represents a group represented by the formula -(CH ₂ ) _r -O-(C ₂ H ₄ O) _s -(C ₃ H ₆ O) _t -R ⁵ (R ⁵ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, r represents a number of 1 to 5, s represents a number of 1 to 50, and t represents a number of 0 to 30), R ³ and R ⁴ represent the same group as either R ¹ or R ² , p represents a number of 5 to 300, and q represents a number of 1 to 50. However, all R ^1s cannot be phenyl groups.]

(In the formula, R ¹ , R ² , p, and q are the same as above, R ⁶ represents an alkyl group having 2 to 20 carbon atoms, R ⁷ and R ⁸ represent the same group as any one of R ¹ , R ² , and R ⁶ , and u represents a number of 1 to 30, provided that all R ^1s are not phenyl groups.)

[In the formula, R ⁹ represents an alkyl group having 1 to 4 carbon atoms, R ¹⁰ represents a group represented by the formula -Q ¹ -O-(C ₂ H ₄ O) _x -(C ₃ H ₆ O) _y R ¹⁴ (Q ¹ represents a divalent hydrocarbon group having 1 to 4 carbon atoms, R ¹⁴ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an acetyl group, x represents a number of 1 or more, and y represents a number of 0 or more), R ¹¹ represents a group represented by the formula -Q ² -O-R ¹⁵ (Q ² represents a divalent hydrocarbon group having 1 to 4 carbon atoms, R ¹⁵ represents a hydrocarbon group having 8 to 30 carbon atoms), R ¹² and R ¹³ represent the same group as any one of R ⁹ , R ¹⁰ , and R ¹¹ , α represents a number of 0 or more, and β and γ represent a number of 1 or more.]

The polyether-modified silicones represented by the above general formulas (1) to (3) may have a branched silicone chain or may be co-modified with functional groups other than polyether, as long as the purpose of the silicone is not exceeded.

Commercially available polyether-modified silicones represented by the above general formula (1) include, for example, "KF-6015" and "KF-6017" manufactured by Shin-Etsu Chemical Co., Ltd., and "SH3775M" (polyoxyethylene-methylpolysiloxane copolymer) and "SH3772C" manufactured by Toray Dow Corning Co., Ltd. Examples of polyether-modified silicones represented by the above general formula (2) include those called alkyl polyether-modified silicones, and examples of commercially available products include, for example, "Abil WE-09" manufactured by Goldschmidt and "KF-6038" manufactured by Shin-Etsu Chemical Co., Ltd. Examples of polyether-modified silicones represented by the above general formula (3) include polyoxyalkylene alkyl ether co-modified organopolysiloxanes, which can be easily produced, for example, by co-modifying methylhydrogenpolysiloxane with polyoxyalkylene allyl ether and allyl alkyl ether.

Also, as the silicone-based surfactant, a partially crosslinked polyether-modified silicone can be used. Such partially crosslinked polyether-modified silicone is obtained by addition polymerization of an organohydrogenpolysiloxane and an aliphatic unsaturated group-containing compound, and examples thereof include those described in JP-A-4-272932 and JP-A-5-140320.

The partially crosslinked polyether-modified organopolysiloxane polymer is represented by the following general formula (4):
R ¹⁶ _a R ¹⁷ _b H _c SiO _(4-a-b-c)/2 (4)
[In the formula, R ¹⁶ represents an alkyl group, an aryl group, an aralkyl group or _a halogenated hydrocarbon group having 1 to 18 carbon atoms which may have a substituent, R ¹⁷ represents a _{polyoxyalkylene} group represented by the formula _-CnH2nO ( _C2H4O ) _d ( _C3H6O ) _eR18 ( ^{R18 represents} a hydrogen atom, a saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms or a monovalent group represented by _-C (O) ^-R19 ( ^R19 represents a saturated aliphatic hydrocarbon group having 1 to 5 carbon atoms), d represents a number of 2 to 200, e represents a number of 0 to 200, d+e represents a number of 3 to 200, and n represents a number of 2 to 6), a represents 1≦a≦2.5, b represents 0.001≦b≦1, and c represents 0.001≦c≦1.]
and/or an organohydrogenpolysiloxane represented by the following general formula (5):
R ¹⁶ _f H _g SiO _(4-f-g)/2 (5)
[In the formula, R ¹⁶ is the same as defined above, f is 1≦f≦3, and g is 0.001≦g≦1.5.]
and an organohydrogenpolysiloxane represented by the following general formula (a):
C _m H _2m-1 O(C ₂ H ₄ O) _h (C ₃ H ₆ O) _i C _m H _2m-1 (a)
(In the formula, h is a number from 2 to 200, i is a number from 0 to 200, h+i is a number from 3 to 200, and m is a number from 2 to 6.)
and/or a polyoxyalkylene represented by the following general formula (b):
R ¹⁶ _j R ²⁰ _k SiO _(4-j-k)/2 (b)
[In the formula, R ¹⁶ is the same as defined above, R ²⁰ represents a monovalent hydrocarbon group having 2 to 10 carbon atoms and an aliphatic unsaturated group at the terminal, j represents 1≦j≦3, and k represents 0.001≦k≦1.5.]
In the present invention, the polymer contains as an essential component the component represented by the above general formula (4) and/or the above general formula (a) in combination with an organopolysiloxane represented by the above general formula (4).

As surfactants other than silicone surfactants, nonionic surfactants are preferred, and polyoxyethylene alkyl ether type nonionic surfactants are more preferred. Commercially available nonionic surfactants include, for example, 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).

Component (D) can be used alone or in combination of two or more. Among the above, component (D) is preferably one or more silicone-based surfactants selected from the group consisting of polyether-modified silicones represented by the general formulas (1) to (3), and more preferably a silicone-based surfactant that is a polyether-modified silicone represented by the general formula (1).

When the skin topical preparation of the present invention contains component (D), the content 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, even more preferably 5% by mass or less, and even more preferably 1.5% by mass or less, from the viewpoint of achieving both an infrared protection effect and a natural appearance when applied to the skin, and from the viewpoint of dispersing an oily component in water or a water-soluble component in oil. The specific range of the content of component (D) in the skin topical preparation of the present invention 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, even more preferably 0.3% by mass or more and 5% by mass or less, and even more preferably 0.5% by mass or more and 1.5% by mass or less.

(Aqueous medium)
The skin topical preparation of the present invention may further contain an aqueous medium from the viewpoint of dispersing component (A) and dispersing or dissolving other blended components to improve application to the skin. The aqueous medium is not particularly limited as long as it is capable of dispersing or dissolving component (A) and other blended components, and examples thereof include water; monohydric alcohols having 4 or less carbon atoms, such as ethanol, isopropyl alcohol, and butyl alcohol; and low-molecular-weight diols and triols having 6 or less 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 water and monohydric alcohols having 4 or less carbon atoms are preferred, and one or more selected from the group consisting of water and ethanol are more preferred.

The content of the aqueous medium in the topical skin preparation can be appropriately selected depending on the formulation of the topical skin preparation, but is preferably 5% by mass or more, more preferably 8% by mass or more, even more preferably 10% by mass or more, preferably 98.8% by mass or less, more preferably 90% by mass or less, even more preferably 70% by mass or less, and even more preferably 50% by mass or less.
The specific range of the content of the aqueous medium in the topical skin preparation is preferably 5% by mass or more and 98.8% by mass or less, more preferably 8% by mass or more and 90% by mass or less, even more preferably 10% by mass or more and 70% by mass or less, and even more preferably 10% by mass or more and 50% by mass or less.

<Other ingredients>
In addition to the above-mentioned components, the topical skin preparation of the present invention may contain other components as necessary, such as ultraviolet scattering agents, antiperspirants, fragrances, moisturizers, thickeners, bactericides, pH adjusters, antioxidants, preservatives, etc.

For example, from the viewpoint of further enhancing the ultraviolet light protection effect, among other components, an ultraviolet light scattering agent may be contained.
As the ultraviolet scattering agent, inorganic particles are preferred, and metal oxide particles are more preferred, because they have a high ultraviolet scattering effect. Examples of the metal oxide include titanium oxide, zinc oxide, iron oxide, zirconium oxide, aluminum oxide, etc. other than component (A), and one or more selected from the group consisting of titanium oxide and zinc oxide other than component (A) are more preferred.

From the viewpoint of dispersibility in topical skin preparations, it is preferable that the inorganic particles used in the UV scattering agent are hydrophobized by surface treatment. Examples of surface treatment methods for hydrophobization include silicone treatment with methylhydrogenpolysiloxane (hydrogendimethicone), methylpolysiloxane (dimethicone), methylhydrogenpolysiloxane-dimethylpolysiloxane copolymer, etc.; fluorine treatment with perfluoroalkyl phosphate ester, perfluoroalcohol, etc.; amino acid treatment with N-acylglutamic acid, etc.; hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, octadecyltrimethoxysilane, octyltriethoxysilane, hexyltrimethoxysilane, octyltriethoxy ... Examples of such surface treatment methods include silane compound treatment with silane, 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. These surface treatment methods can be used alone or in combination.

The particle shape of the ultraviolet scattering agent may be spherical, rod-like, spindle-like, needle-like, plate-like, irregular, etc., but is not particularly limited as long as it has an ultraviolet scattering effect.
The number-average particle diameter of the ultraviolet scattering agent is usually 1 nm or more, and from the viewpoint of obtaining an excellent ultraviolet protection effect, it is preferably 5 nm or more, more preferably 8 nm or more, and even more preferably 10 nm or more, and from the viewpoint of a natural appearance when applied to the skin, it is, for example, 500 nm or less, preferably 300 nm or less, more preferably 100 nm or less, and even more preferably 60 nm or less.
The number-average particle size is obtained by measuring the maximum minor axis of particle diameters of 300 particles in an image of a transmission electron microscope (TEM) at a magnification of 100,000 and calculating the average value. Here, the maximum minor axis means the minor axis that is the largest among the minor axes perpendicular to the major axis.

Commercially available titanium oxide particles other than component (A) used in UV scattering agents include, for example, "MT-100TV" (aluminum hydroxide, treated with stearic acid) and "MTY-110M3S" (aluminum hydroxide, silica, treated with hydrogen dimethicone) manufactured by Teika Co., Ltd.

Commercially available zinc oxide particles other than component (A) used in UV scattering agents include, for example, "FINEX-50-LPTM" (treated with dimethicone), "FINEX-25" (no surface treatment), and "FINEX-25LP" (treated with dimethicone) manufactured by Sakai Chemical Industry Co., Ltd., and "MZ-300" (no surface treatment), "MZ-504R3M" (treated with hydrogen dimethicone), and "MZY-303S" (treated with hydrogen dimethicone) manufactured by Teika Co., Ltd. Hydrogen dimethicone treatment), MZ-306X (triethoxysilylethyl polydimethylsiloxyethylhexyl dimethicone treatment), MZ-200 (no surface treatment), MZY-203S (hydrogen dimethicone treatment), MZ-150 (no surface treatment), MZY-153S (hydrogen dimethicone treatment), MZ-505S, MZY-505S, etc.

The ultraviolet scattering agents can be used alone or in combination of two or more.
When the skin external preparation of the present invention contains an ultraviolet scattering agent, its content 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 ultraviolet protection effect.In addition, from the viewpoint of easy spreading on skin and smoothness when applied to skin, the content is preferably 20% by mass or less, more preferably 18% by mass or less, and even more preferably 15% by mass or less.The specific range of the content of the ultraviolet scattering agent in the skin external preparation is preferably 1% by mass or more and 20% by mass or less, more preferably 3% by mass or more and 18% by mass or less, and even more preferably 5% by mass or more and 15% by mass or less.

(Method of manufacturing topical skin preparation)
The method for producing the skin external preparation of the present invention is not particularly limited, and known methods can be used appropriately according to the formulation of the skin external preparation.For example, the method of blending components (A), (B) and all other components and mixing uniformly with a disperser or the like can be mentioned.Alternatively, the method of blending all components other than the aqueous medium and mixing uniformly with a disperser or the like, and then blending the aqueous medium and further stirring and mixing with a homogenizer or the like can also be used.

[Method for protecting the skin from infrared rays and ultraviolet rays]
The present invention also provides a method for protecting the skin from infrared rays and ultraviolet rays, which comprises applying the topical skin preparation of the present invention to the skin. The 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.

In the protection method of the present invention, the infrared protection rate at a wavelength of 1500 nm is preferably 10% or more, more preferably 12% or more, and even more preferably 15% or more. If the infrared protection rate at a wavelength of 1500 nm is 10% or more, the skin feels good insulated from heat. The infrared protection rate (%) is a value expressed as 100-X (%), where X (%) is the infrared transmittance measured with a spectrophotometer, and can be specifically measured by the method described in the Examples.

By applying the topical skin preparation of the present invention to the skin, it is possible to effectively protect against both infrared rays and ultraviolet rays. The ultraviolet ray protection effect is preferably an SPF value of 10 or more, more preferably 20 or more, and even more preferably 30 or more. The SPF value can be specifically measured by the method described in the Examples.

In relation to the above-mentioned embodiment, the present invention further discloses the following embodiments.
＜1＞
A topical skin preparation comprising a plate-like metal oxide (A) having a thickness of 30 nm or more and 360 nm or less and an aspect ratio of 50 to 300, and an ultraviolet absorber (B), wherein the mass ratio [(A)/(B)] is 0.1 to 5, preferably 0.3 to 3.5, more preferably 0.3 to 3.5, even more preferably 0.3 to 2.3, still more preferably 0.55 to 1.5, still more preferably 0.55 to 1.2, and even more preferably 0.7 to 1.2.
＜2＞
The external skin preparation described in <1>, wherein the thickness of component (A) is preferably 50 nm or more, more preferably 60 nm or more, even more preferably 80 nm or more, still more preferably 105 nm or more, even more preferably 125 nm or more, and also preferably 330 nm or less, 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, and even more preferably 150 nm or less.
＜3＞
The topical skin preparation according to <1> or <2>, wherein the aspect ratio of component (A) is preferably 55 or more, more preferably 65 or more, even more preferably 70 or more, still more preferably 100 or more, and is preferably 230 or less, more preferably 200 or less, even more preferably 140 or less, still more preferably 125 or less, and still more preferably 120 or less.
＜4＞
The external skin preparation according to any one of <1> to <3>, wherein the metal oxide constituting the component (A) is preferably at least one selected from the group consisting of titanium oxide, zinc oxide, zirconium oxide, iron oxide, aluminum oxide, and cerium oxide, more preferably at least one selected from the group consisting of titanium oxide and zinc oxide, and even more preferably titanium oxide.
＜5＞
The content of component (A) is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 6% by mass or more, still more preferably 8% by mass or more, and is preferably 35% by mass or less, more preferably 25% by mass or less, even more preferably 17% by mass or less, and still more preferably 12% by mass or less. The topical skin preparation according to any one of <1> to <4>,
＜6＞
Component (B) is an oil-soluble organic ultraviolet absorber, preferably one or more selected from the group consisting of 2-ethylhexyl paramethoxycinnamate, 4-tert-butyl-4'-methoxydibenzoylmethane, octocrylene, 2-ethylhexyl dimethoxybenzylidene dioxoimidazolidinepropionate, diethylaminohydroxybenzoylhexyl benzoate, bisethylhexyloxyphenol methoxyphenyl triazine, methylene bisbenzotriazolyl tetramethylbutylphenol, and 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine, more preferably paramethoxycinnamate. The topical skin preparation according to any one of <1> to <5>, wherein the active ingredient is one or more selected from the group consisting of 2-ethylhexyl cinnamate, diethylamino hydroxybenzoyl hexyl benzoate, bisethylhexyloxyphenol methoxyphenyl triazine, and 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine, more preferably one or more selected from the group consisting of 2-ethylhexyl p-methoxycinnamate, diethylamino hydroxybenzoyl hexyl benzoate, and bisethylhexyloxyphenol methoxyphenyl triazine, and even more preferably a combination of two or more of these active ingredients.
＜７＞
The content of component (B) is preferably 0.2% by mass or more, more preferably 1.5% by mass or more, even more preferably 5% by mass or more, still more preferably 7% by mass or more, and is preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less, and still more preferably 15% by mass or less.
＜8＞
The external skin preparation according to any one of <1> to <7>, wherein the total content of the component (A) and the component (B) is preferably 1.2% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and still more preferably 15% by mass or more and 100% by mass or less.
＜9＞
The topical skin preparation according to any one of <1> to <8>, further comprising a non-volatile oil (C), the content of which is preferably 1 mass% or more, more preferably 5 mass% or more, even more preferably 15 mass% or more, preferably 40 mass% or less, more preferably 35 mass% or less, and even more preferably 25 mass% or less.
＜10＞
The external skin preparation according to <9>, wherein the component (C) is one or more selected from the group consisting of ester oils, silicone oils, hydrocarbon oils, higher fatty acids, and higher alcohols, preferably one or more selected from the group consisting of ester oils, silicone oils, and hydrocarbon oils, more preferably one or more selected from the group consisting of ester oils and hydrocarbon oils, and even more preferably one or more selected from the group consisting of alkyl benzoates (C12-15), isopropyl palmitate, and light liquid isoparaffin.

<11>
The external skin preparation according to <9> or <10>, wherein the mass ratio [(A)/(C)] is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, still more preferably 0.45 or more, and is preferably 4 or less, more preferably 2 or less, even more preferably 1.5 or less, and still more preferably 0.75 or less.
＜12＞
The external skin preparation according to any one of <9> to <11>, wherein the mass ratio [(B)/(C)] is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, still more preferably 0.45 or more, and is preferably 4 or less, more preferably 2 or less, even more preferably 1.5 or less, and still more preferably 0.75 or less.
＜13＞
The topical skin preparation according to any one of <1> to <12>, further comprising a volatile oil (C)', the content of which is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, and is preferably 75% by mass or less, more preferably 70% by mass or less, even more preferably 60% by mass or less.
＜14＞
The skin topical preparation according to <13>, wherein the component (C)' is a volatile silicone oil, preferably at least one selected from the group consisting of linear organopolysiloxanes and cyclic organopolysiloxanes, more preferably cyclic organopolysiloxanes, and even more preferably decamethylcyclopentasiloxane.
＜15＞
The topical skin preparation according to any one of <1> to <14>, further comprising a surfactant (D), the content of which 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 is preferably 15% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and still more preferably 1.5% by mass or less.
＜16＞
The skin external preparation according to <15>, wherein the component (D) contains at least a silicone-based surfactant, and preferably contains a nonionic silicone-based surfactant.
＜１７＞
A topical skin preparation comprising one or more plate-like metal oxides (A) selected from the group consisting of plate-like titanium oxide and plate-like zinc oxide, the plate-like metal oxides having a thickness of 80 nm or more and 280 nm or less, and an ultraviolet absorber (B), the content of component (A) being 6 mass% or more and 35 mass% or less, and the mass ratio [(A)/(B)] being 0.1 or more and 5 or less.
＜18＞
A skin topical preparation comprising one or more plate-like metal oxides (A) selected from the group consisting of plate-like titanium oxide and plate-like zinc oxide, each having a thickness of 80 nm or more and 280 nm or less, an ultraviolet absorber (B), and a non-volatile oil (C), wherein the content of component (A) is 6 mass% or more and 17 mass% or less, and the mass ratio [(A)/(B)] is 0.55 or more and 1.5 or less.
＜19＞
The external skin preparation according to any one of <1> to <18>, which is a skin cosmetic.
＜20＞
A method for protecting the skin from infrared rays and ultraviolet rays, comprising applying the external skin preparation according to any one of <1> to <19> to the skin.

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

(Measurement of thickness, major axis, aspect ratio)
The thickness, major axis, and aspect ratio of component (A) and inorganic particles other than component (A) (referred to as "component (A)'" in the table) were determined by observation using a scanning electron microscope ("VE-9800" manufactured by Keyence Corporation) under conditions of an acceleration voltage of 10 keV and an observation magnification of 10,000 times.
The thickness of component (A) and plate-like component (A)' was determined by measuring the thickness of 50 particles in the observed image and calculating the average value per particle. The aspect ratio was determined by measuring the thickness and major axis of 50 particles, calculating the aspect ratio (major axis/thickness) of each particle, and averaging the results.

(Infrared protection rate)
28.5 mg of each skin topical agent was applied to a 5 cm x 5 cm polymethylmethacrylate (PMMA) substrate ("HD6" manufactured by HelioScreen) and dried for 15 minutes to prepare a measurement sample. Similarly, glycerin was applied to a PMMA substrate and dried for 15 minutes to prepare a control sample. The transmittance of the measurement sample and the control sample was measured at a wavelength of 1500 nm using a spectrophotometer ("UV-3600" manufactured by Shimadzu Corporation) in integrating sphere mode. The transmittance of the measurement sample divided by the transmittance of the control sample was defined as the transmittance X (%), and 100-X (%) was defined as the infrared protection rate. The larger this value, the higher the infrared protection effect.

(UV protection effect (in vitro SPF value))
28.5 mg of each skin topical agent was applied to a 5 cm x 5 cm PMMA substrate ("HD6" manufactured by HelioScreen) and dried for 15 minutes to prepare a measurement sample. Similarly, glycerin was applied to a PMMA substrate and dried for 15 minutes to prepare a control sample. Using an SPF analyzer ("UV-2000S" manufactured by Labsphere), the control sample was used as a blank and the transmittance was subtracted beforehand to measure the in vitro SPF value of the measurement sample.

(Natural appearance when applied to the skin)
About 0.1 g of each skin preparation was applied to an area of about 2 cm x 5 cm on the inside of the forearm, and the whiteness immediately after application was evaluated on a 5-point scale, with 1 being a very white and unnatural appearance and 5 being a natural whiteness with no discomfort. Evaluation was performed by 5 expert panelists, and the average score was used as the evaluation result.
<Evaluation criteria>
1: Very white, very unnatural 2: Somewhat white, unnatural 3: Neither 4: Natural white, but slightly unnatural 5: Natural white, no discomfort

(Makeup paste after application)
About 0.1 g of each skin topical agent was applied to an area of about 2 cm x 5 cm on the inside of the forearm, and a powder foundation was applied on top of it. The "goodness of application" of the foundation was evaluated on a 5-point scale, with 1 point being when the foundation was uneven and applied very poorly, and 5 points being when the foundation was even and applied very well. The evaluation was performed by 5 expert panelists, and the average score was recorded as the evaluation result.
<Evaluation criteria>
1: The foundation is uneven and applies very poorly. 2: The foundation is slightly uneven and applies slightly poorly. 3: Neither. 4: The foundation is slightly uniform and applies slightly well. 5: The foundation is uniform and applies very well.

(comprehensive evaluation)
In the evaluation results shown in Table 1, a product was rated as passing (rating A) when the infrared protection rate was 10% or more, the in vitro SPF value was 10 or more, the naturalness of appearance when applied to the skin was 3 or more, and the makeup spread after application was 3 or more. A product was rated as failing (rating C) when any of the evaluation items did not meet the above criteria, and these are shown in Table 1.

Production Example 1 (Production of Plate-shaped Titanium Oxide 3a)
A toluene solution (hereinafter referred to as the first liquid) in which 30% by mass of tetra-n-butyl orthotitanate was dissolved was fed from the inner opening of a double-tube reactor (inner pipe opening diameter 170 μm, outer pipe opening diameter 400 μm) at a flow rate of 0.29 ml/min, and a 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide solution (hereinafter referred to as the second liquid) in which 1% by mass of water was dissolved was fed from the outer opening at a flow rate of 20.8 ml/min, and the two liquids were brought into contact with each other and subjected to a sol-gel reaction to obtain a plate-like titanium oxide gel. The temperature (reaction temperature) of the first and second liquids was 25° C., and the contact time (reaction time) of the first and second liquids at the liquid contact portion was 3 seconds. The obtained slurry was filtered through a metal mesh, and the plate-like titanium oxide gel remaining on the metal mesh was washed with ethanol, and then dried and fired to obtain a solid plate-like titanium oxide 3a. The thickness and aspect ratio of the plate-like titanium oxide 3a measured by the above method were 264 nm and 57, respectively.

Production Example 2 (Production of Comparative Plate-shaped Titanium Oxide 1b)
Comparative plate-like titanium oxide 1b was obtained in the same manner as in Production Example 1, except that the flow rates of the first liquid and the second liquid were 0.14 ml/min and 10.4 ml/min, respectively. The thickness and aspect ratio of comparative plate-like titanium oxide 1b, measured by the above method, were 388 nm and 39, respectively.

Examples 1 to 12 and Comparative Examples 1 to 4 (Production and Evaluation of Skin Topical Preparations)
All the ingredients shown in Table 1 except for water and ethanol were blended and mixed uniformly using a disper. Water and ethanol were then added to the resulting mixture, and the mixture was mixed uniformly using a homogenizer to produce a skin topical preparation having the composition shown in Table 1. The obtained skin topical preparation was evaluated using the method described above. The results are shown in Table 1. The blending amounts shown in Table 1 are the active ingredient amounts (mass%) of each ingredient.

The ingredients in Table 1 are as follows:
*1: CQV's "Featheleve PT-9001K" (alkyl acrylate / dimethicone) copolymer 7.5% by mass coating product *2: CQV's "Featheleve PT-7801K" (alkyl acrylate / dimethicone) copolymer 7.5% by mass coating product *3: Plate-shaped titanium oxide 3a obtained in Production Example 1 (alkyl acrylate / dimethicone) copolymer 7.5% by mass coating product *4: Comparative plate-shaped titanium oxide 1b obtained in Production Example 2 (alkyl acrylate / dimethicone) copolymer 7.5% by mass coating product *5: BASF's "Flamenco Satin Blue" (titanium oxide coating layer thickness: 10 nm) (alkyl acrylate / dimethicone) copolymer 7.5% by mass coating product *6: BASF's "Ubinal MC80"
*7: "Ubinal Aplus" manufactured by BASF
*8: "Chinosorb S" manufactured by BASF
*9: "Finsolv TN" manufactured by Innospec Active Chemicals
*10: "Excepar IPP" manufactured by Kao Corporation
*11: NOF Corp.'s "Pearlream 4", light liquid isoparaffin (hydrogenated polyisobutene)
*12: "TSF405" manufactured by Momentive Performance Materials
*13: "SH3775M" manufactured by Toray Dow Corning Co., Ltd., polyoxyethylene methylpolysiloxane copolymer (PEG-12 dimethicone)

From Table 1, it can be seen that the skin topical preparations of Examples 1 to 12 can achieve both infrared and ultraviolet protection effects, and have a natural appearance when applied to the skin and good makeup application after application. In addition, they are less sticky, and therefore have an excellent feel when used. Comparing Examples 1 to 3 with Comparative Example 1, it can be seen that the use of plate-like titanium oxide having a thickness within the range specified in the present invention improves the infrared protection effect, and also improves the natural appearance when applied to the skin and good makeup application after application. In particular, the use of component (A) having a thickness within the range of 105 nm to 270 nm, and further 125 nm to 230 nm, further improves the infrared protection effect and increases the ultraviolet protection effect.
In contrast, the skin preparation of Comparative Example 1, which uses plate-like titanium oxide with a thickness of more than 360 nm instead of component (A), has a low infrared protection effect, and the natural appearance when applied to the skin and the makeup application after application are also deteriorated.Comparative Example 2, in which the mass ratio [(A)/(B)] of component (A) to component (B) in the skin preparation is less than 0.1, and Comparative Example 3, in which plate-like inorganic particles other than metal oxide are used instead of component (A), do not provide excellent infrared protection effect.In addition, the skin preparation of Comparative Example 4, which does not contain component (B), has a reduced ultraviolet protection effect.

The skin topical preparation of the present invention has excellent infrared and ultraviolet protection effects, does not turn white when applied to the skin, has a natural appearance, provides good makeup application after application, is less sticky, and has an excellent feel when used, making it useful, for example, as a skin cosmetic.

Claims (4)

A skin topical preparation comprising a plate-like metal oxide (A) having a thickness of 30 nm or more and 360 nm or less and an aspect ratio of 50 to 300, and an ultraviolet absorber (B), wherein the mass ratio [(A)/(B)] is 0.1 to 5,
The plate-like metal oxide (A) contains plate-like titanium oxide,
The ultraviolet absorber (B) is an oil-soluble organic ultraviolet absorber,
A skin topical preparation, wherein the content of the plate-like metal oxide (A) is 1% by mass or more and 35% by mass or less. The topical skin preparation according to claim 1, further comprising a non-volatile oil (C). The topical skin preparation according to claim 1 or 2, which is a skin cosmetic. A method for protecting the skin from infrared and ultraviolet rays, comprising applying to the skin the topical skin preparation according to any one of claims 1 to 3.