JP7680833B2 - Infrared protection skin agent - Google Patents

Description

The present invention relates to a skin preparation for external use.

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 the dermis and subcutaneous tissue 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 topical skin preparations with improved infrared protection function. Furthermore, among topical skin preparations, skin cosmetics are also required to have a color that blends with the skin color, since reddish or bluish colors will result in unnatural colors when applied to the skin.
To provide an external preparation for the skin which has an excellent infrared protection effect, is unlikely to give off a reddish or bluish tinge when applied to the skin, and has a natural color that blends in with the skin color.

The present inventors have found that the above-mentioned problems can be solved by an external skin preparation containing a combination of plate-like metal oxides having different thicknesses in a specified ratio, the combination having a specified thickness range.
That is, the present invention relates to the following [1] and [2].
[1] The following components (a) to (c):
(a) a plate-like metal oxide having a thickness of 100 nm or more and 120 nm or less;
(b) a plate-like metal oxide having a thickness of 125 nm or more and 145 nm or less, and (c) a plate-like metal oxide having a thickness of 180 nm or more and 200 nm or less;
wherein, relative to a total amount of the components (a) to (c) being 100% by mass, the amount of component (a) is 5% by mass or more and 70% by mass or less, the amount of component (b) is 15% by mass or more and 75% by mass or less, and the amount of component (c) is 5% by mass or more and 70% by mass or less.
[2] A method for protecting the skin from infrared 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 protection effects, and when applied to the skin, it is unlikely to produce a reddish or bluish tinge, and can achieve a natural color that blends in with the skin color, making it useful, for example, as a skin cosmetic.

1 is a three-phase diagram showing the mass percentages of components (a), (b), and (c) in a skin topical preparation in which the total amount of components (a) to (c) is 100% by mass.

[External skin preparations]
The skin topical preparation of the present invention comprises the following components (a) to (c):
(a) a plate-like metal oxide having a thickness of 100 nm or more and 120 nm or less;
(b) a plate-like metal oxide having a thickness of 125 nm or more and 145 nm or less, and (c) a plate-like metal oxide having a thickness of 180 nm or more and 200 nm or less;
and the amount of component (a) is from 5 to 70% by mass, the amount of component (b) is from 15 to 75% by mass, and the amount of component (c) is from 5 to 70% by mass, relative to 100% by mass of the total amount of components (a) to (c).
The skin external preparation of the present invention has the above-mentioned composition, and thus has excellent infrared protection effect and also has a natural color that blends in with the skin color when applied to the skin.

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, 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.

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.

<Components (a) to (c): Plate-like Metal Oxide>
The skin topical preparation of the present invention comprises the following components (a) to (c):
(a) a plate-like metal oxide having a thickness of 100 nm or more and 120 nm or less;
(b) a plate-like metal oxide having a thickness of 125 nm or more and 145 nm or less, and (c) a plate-like metal oxide having a thickness of 180 nm or more and 200 nm or less.
By blending the above-mentioned plate-like metal oxides as components (a) to (c) in the prescribed ratios, the topical skin preparation of the present invention has an excellent infrared protection effect, provides a high heat shielding effect, is less likely to turn white, and has a natural color that blends in with the skin when applied to the skin. The reason for this is unclear, but is thought to be as follows.

It is known that the skin external preparation containing inorganic particles such as titanium oxide has higher infrared protection effect when using inorganic particles with larger particle size.However, there is a limit to the improvement of infrared protection effect just by using inorganic particles with larger particle size.In addition, when spherical inorganic particles with particle size larger than the wavelength of visible light are mixed into a skin external preparation, there is a drawback that when applied to skin, visible light is scattered on the particle surface, so that the skin tends to become white.
In response to this, the inventors have discovered that by using a plate-like metal oxide of a specified thickness as an infrared protective agent in an external skin preparation, it is possible to selectively increase the reflectance of light in the infrared range while reducing the reflectance of light in the visible range through the optical interference effect, thereby achieving both an infrared protective effect and the effect of being less likely to turn white when applied to the skin.
On the other hand, it has been found that skin topical preparations containing plate-like metal oxides as infrared protection agents may have an unnatural color that does not blend with the skin, such as a reddish or blueish color, when applied to the skin. In response to this problem, the present inventors have found that by blending components (a) to (c), which are plate-like metal oxides with different thicknesses, in the above-mentioned predetermined ratio, it is possible to achieve both a high infrared protection effect and a natural color when applied to the skin. Regarding the color, components (a) to (c) exhibit red, blue, and green interference colors, respectively, due to the wavelength of reflected light, and it is believed that by setting the blending amount of each component within a predetermined range, a natural color that blends with the skin color when applied to the skin can be obtained.

From the viewpoint of obtaining an excellent infrared protection effect by the above-mentioned mechanism of action, and from the viewpoint of preventing the skin from turning white when applied to the skin and obtaining a natural color, it is preferable that the thicknesses of the components (a) to (c) are each within the following ranges.
The thickness of component (a) is 100 nm or more, preferably 105 nm or more, and 120 nm or less, preferably 115 nm or less. Component (a) having a thickness in the above range exhibits a reddish interference color due to the wavelength of reflected light.
The thickness of component (b) is 125 nm or more, preferably 130 nm or more, and 145 nm or less, preferably 140 nm or less. Component (b) having a thickness in the above range exhibits a bluish interference color due to the wavelength of reflected light.
The thickness of component (c) is 180 nm or more, preferably 185 nm or more, and 200 nm or less, preferably 195 nm or less. Component (c) having a thickness in the above range exhibits a greenish interference color due to the wavelength of reflected light.
The thicknesses of the components (a) to (c) can be determined from images observed with a scanning electron microscope (SEM). Specifically, the plate-like metal oxides of the components (a) to (c) are observed with an 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 thicknesses of the components (a) to (c) can be measured by the method described in the Examples.

From the viewpoint of reducing glare when the skin topical preparation is applied to the skin, the average particle size of the components (a) to (c) is preferably 20 μm or less, more preferably 15 μm or less, even more preferably 12 μm or less, and even more preferably 10 μm or less. On the other hand, from the viewpoint of obtaining an excellent infrared protection effect and from the viewpoint of preventing the skin topical preparation from becoming white when applied to the skin and obtaining a natural color, the average particle size of the components (a) to (c) is preferably 1 μm or more, more preferably 2 μm or more, even more preferably 3 μm or more, and even more preferably 5 μm or more. The specific range of the average particle size of the components (a) to (c) is preferably 1 μm or more and 20 μm or less, more preferably 2 μm or more and 15 μm or less, even more preferably 2 μm or more and 12 μm or less, even more preferably 3 μm or more and 10 μm or less, and even more preferably 5 μm or more and 10 μm or less.
The average particle size of the components (a) to (c) is a median diameter (D50) measured based on the particle size standard volume using a laser diffraction/scattering type particle size distribution measuring device, and specifically, can be measured by the method described in the examples.

In addition, from the viewpoint of obtaining an excellent infrared protection effect and obtaining a natural color when the skin topical preparation is applied to the skin, the aspect ratio of components (a) to (c) is preferably 10 or more, more preferably 20 or more, even more preferably 30 or more, and even more preferably 35 or more. In addition, from the viewpoint of obtaining an excellent infrared protection effect and from the viewpoint of preventing the skin topical preparation from becoming white when applied to the skin and reducing glare, the aspect ratio is preferably 200 or less, more preferably 150 or less, even more preferably 100 or less, and even more preferably 90 or less. The specific range of the aspect ratio of components (a) to (c) is preferably 10 or more and 200 or less, more preferably 10 or more and 150 or less, even more preferably 10 or more and 100 or less, even more preferably 20 or more and 100 or less, even more preferably 30 or more and 100 or less, and even more preferably 35 or more and 90 or less.
The aspect ratio of the components (a) to (c) can be calculated from (average particle size/thickness).

The degree of glare when a topical skin preparation is applied to the skin can be evaluated by measuring the gloss value of the coating film obtained by applying the topical skin preparation at an angle of 60° using a gloss value measuring device.

The metal oxide constituting components (a) to (c) is preferably a high refractive index material, which provides a higher light interference effect. From this viewpoint, preferred metal oxides constituting components (a) to (c) include titanium oxide, zinc oxide, zirconium oxide, iron oxide, aluminum oxide, and cerium oxide. Among these, preferred is one or more selected from the group consisting of titanium oxide and zinc oxide, more preferred is titanium oxide. That is, components (a) to (c) are preferably one or more 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 oxides in components (a) to (c) may be untreated, or may be surface-treated, such as hydrophobized, by a known method, as necessary, to enhance dispersibility in topical skin preparations. The plate-like metal oxides in components (a) to (c) are to be distinguished from particles other than metal oxides whose surfaces have been surface-treated with metal oxides.

Examples of surface treatment agents used in the surface treatment of the plate-like metal oxides of components (a) to (c) 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 components (a) to (c) 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.
The alkylalkoxysilane used as the surface treatment agent is preferably one having a branched or linear alkyl group having 6 to 20 carbon atoms, such as octyltriethoxysilane and octyltrimethoxysilane.
From the viewpoint of improving the infrared protection effect, the surface treatment agent is preferably at least one selected from the group consisting of methylpolysiloxane, dimethylpolysiloxane, methylhydrogenpolysiloxane, (alkyl acrylate/dimethicone) copolymer, and octyltriethoxysilane.

In the topical skin preparation of the present invention, the amount of component (a) is 5% by mass or more and 70% by mass or less, the amount of component (b) is 15% by mass or more and 75% by mass or less, and the amount of component (c) is 5% by mass or more and 70% by mass or less, relative to the total amount of components (a) to (c) being 100% by mass. When the amount of each component relative to the total amount of components (a) to (c) being 100% by mass, is within the above range, both an excellent infrared protection effect and a natural color when the topical skin preparation is applied to the skin can be achieved. In particular, it has been found that, with regard to the infrared protection effect, an excellent infrared protection effect can be obtained when the amount of component (a) is 70% by mass or less relative to the total amount of components (a) to (c) being 100% by mass.

From the viewpoint of achieving both an excellent infrared protection effect and a natural color when applied to the skin, the topical skin preparation of the present invention preferably satisfies the following condition 1 in terms of the blending ratio of components (a), (b), and (c) relative to 100 mass% of the total blending amount of components (a) to (c), and more preferably satisfies the following condition 2.
Condition 1: In a three-phase diagram showing the mass% of components (a), (b), and (c) relative to 100 mass% of the total amount of components (a) to (c), the blending ratio of each component is within the range of a composition region surrounded by six composition points shown below.
(a, b, c) = (70, 15, 15), (28, 26, 46), (5, 40, 55), (5, 67, 28), (20, 68, 12), (57, 33, 10)
Condition 2: In a three-phase diagram showing the mass% of components (a), (b), and (c) relative to 100 mass% of the total amount of components (a) to (c), the blending ratio of each component is within the range of a composition region surrounded by six composition points shown below.
(a, b, c) = (50, 28, 22), (25, 45, 30), (25, 32, 43), (15, 43, 42), (23, 55, 22), (42, 43, 15)

The above conditions 1 and 2 will be described with reference to the drawings.
Fig. 1 is a three-phase diagram showing the mass percentages of components (a), (b) and (c) in a total amount of 100% by mass of components (a) to (c) in a skin topical preparation. In the three-phase diagram in Fig. 1, region 1 surrounded by a thick solid line indicates a composition region in which the amount of component (a) is 5% to 70% by mass, the amount of component (b) is 15% to 75% by mass, and the amount of component (c) is 5% to 70% by mass, relative to the total amount of components (a) to (c) of 100% by mass.
In the three-phase diagram of Fig. 1, the region 2 enclosed by the dashed line is a composition region that satisfies the above-mentioned condition 1. In Fig. 1, six composition points, (a, b, c) = (70, 15, 15), (28, 26, 46), (5, 40, 55), (5, 67, 28), (20, 68, 12), and (57, 33, 10), are indicated by "◯".
In the three-phase diagram of Fig. 1, the region 3 surrounded by a dashed line is a composition region that satisfies the above-mentioned condition 2. In Fig. 1, six composition points, (a, b, c) = (50, 28, 22), (25, 45, 30), (25, 32, 43), (15, 43, 42), (23, 55, 22), and (42, 43, 15), are indicated by "△".

The total amount of the components (a) to (c) in the skin topical preparation of the present invention is preferably 1% by mass or more, more preferably 1.5% by mass or more, and even more preferably 2% by mass or more, from the viewpoint of obtaining an excellent infrared protection effect. In addition, from the viewpoint of preventing the skin topical preparation from becoming white when applied to the skin and obtaining a natural color, as well as from the viewpoint of economy, it is preferably 35% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less, even more preferably 15% by mass or less, and even more preferably 10% by mass or less. The specific range of the total amount of the components (a) to (c) in the skin topical preparation of the present invention is preferably 1% by mass or more and 35% by mass or less, more preferably 1% by mass or more and 25% by mass or less, even more preferably 1% by mass or more and 20% by mass or less, even more preferably 1% by mass or more and 15% by mass or less, even more preferably 1.5% by mass or more and 10% by mass or less, and even more preferably 2% by mass or more and 10% by mass or less.

The topical skin preparation of the present invention does not exclude the incorporation of plate-like metal oxides other than components (a) to (c), but from the viewpoint of obtaining the effects of the present invention, it is preferable that the incorporation amount is small. Specifically, the ratio of components (a) to (c) in the total amount of plate-like metal oxides incorporated in the topical skin preparation is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, and is 100% by mass or less.

As the components (a) to (c), 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. It is more preferable to use these plate-like titanium oxides that have been subjected to the above-mentioned surface treatment as the components (a) to (c).
In order to adjust the aspect ratio or average particle size of the plate-like metal oxide to the above range, a commercially available plate-like metal oxide or a surface-treated product thereof may be pulverized by a pulverizer and used as components (a) to (c). The pulverization method is not particularly limited, and known methods can be used. When a surface-treated plate-like metal oxide is used, the pulverization may be performed either before or after the surface treatment.

<Component (d): Texture improver>
When the topical skin preparation of the present invention is blended with an oil or the like described below, it is preferable for the skin preparation to further contain a feel enhancer as component (d) in order to suppress stickiness when applied to the skin and obtain a smooth and pleasant feel.
The feel improver may be any of organic particles, inorganic particles other than the above components (a) to (c), and mixtures thereof, and those usually incorporated in cosmetics can be used. From the viewpoint of obtaining a good feel when applied to the skin, the particle shape is preferably spherical. In addition, particles having an uneven surface or porous particles may be used.

Examples of organic particles used as component (d) include resin particles made of resins such as acrylic resin, silicone resin, polystyrene resin, polyamide resin, polyester resin, polyolefin resin, polystyrene resin, polyurethane resin, vinyl resin, urea resin, phenol resin, fluororesin, melamine resin, epoxy resin, polycarbonate resin, acrylic-silicone copolymer resin, acrylic-styrene copolymer resin, cellulose, etc. These resin particles may be crosslinked or non-crosslinked resin particles.
The inorganic particles other than the components (a) to (c) are preferably metal oxide particles, and examples of the metal oxide include titanium oxide, zinc oxide, zirconium oxide, iron oxide, aluminum oxide, cerium oxide, etc. Among these, one or more types selected from the group consisting of titanium oxide and zinc oxide are preferred, and titanium oxide is more preferred.

Among the above, component (d) is preferably spherical inorganic particles, more preferably spherical metal oxide particles, even more preferably one or more selected from the group consisting of spherical titanium oxide particles and spherical zinc oxide particles, and even more preferably spherical titanium oxide particles.

The average particle size of the particles used as component (d) is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.5 μm or more, from the viewpoint of suppressing stickiness when applied to the skin and obtaining a good feel, and from the viewpoint of suppressing stickiness when applied to the skin and not easily turning white when the topical skin preparation is applied to the skin, it is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 2 μm or less. The specific range of the average particle size of the particles used as component (d) is preferably 0.1 μm or more and 10 μm or less, more preferably 0.2 μm or more and 5 μm or less, and even more preferably 0.5 μm or more and 2 μm or less. The average particle size can be measured by the same method as above.

When component (d) is used in the skin topical preparation of the present invention, the content of the component (d) in the skin topical preparation is preferably 1% by mass or more, more preferably 1.5% by mass or more, and even more preferably 2% by mass or more, from the viewpoint of suppressing stickiness when applied to the skin and obtaining a good feel, and from the viewpoint of suppressing stickiness when applied to the skin and not easily turning white when applied to the skin, the content is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. The specific range of the content of component (d) in the skin topical preparation of the present invention is preferably 1% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, even more preferably 1% by mass or more and 10% by mass or less, even more preferably 1.5% by mass or more and 10% by mass or less, and even more preferably 2% by mass or more and 10% by mass or less.

In the skin topical preparation of the present invention, the mass ratio [{(a)+(b)+(c)}/(d)] of the total amount of ingredients (a)-(c) to ingredient (d) is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.5 or more, from the viewpoint of obtaining an excellent infrared protection effect and from the viewpoint of preventing the skin topical preparation from turning white when applied to the skin and obtaining a natural color. In addition, from the viewpoint of suppressing stickiness when applied to the skin and obtaining a good feel, it is preferably 5 or less, more preferably 3 or less, even more preferably 2 or less, and even more preferably 1.5 or less. The specific range of the mass ratio [{(a)+(b)+(c)}/(d)] is preferably 0.1 or more and 5 or less, more preferably 0.2 or more and 3 or less, even more preferably 0.5 or more and 2 or less, and even more preferably 0.5 or more and 1.5 or less.

<Component (e): Ultraviolet Absorber>
From the viewpoint of imparting an ultraviolet protection effect in addition to an infrared protection effect, the external skin preparation of the present invention preferably further contains an ultraviolet absorbing agent as component (e).
Component (e) 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 (e) is preferably an oil-soluble organic UV absorber. Note that "oil-soluble" means water-insoluble, specifically means that the solubility in water is 1 w/w% or less.
From the viewpoint of obtaining the effects of the present invention, the component (e) is distinguished from inorganic ultraviolet absorbents such as an ultraviolet absorbent 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, component (e) is preferably one or more selected from the group consisting of 2-ethylhexyl paramethoxycinnamate, 4-tert-butyl-4'-methoxydibenzoylmethane, octocrylene, dimethoxybenzylidene dioxoimidazolidinepropionate 2-ethylhexyl, diethylaminohydroxybenzoylhexyl benzoate, bisethylhexyloxyphenol methoxyphenyl triazine, methylene bisbenzotriazolyl tetramethylbutylphenol, and 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine, and more preferably one or more selected from the group consisting of 2-ethylhexyl paramethoxycinnamate, diethylaminohydroxybenzoylhexyl benzoate, bisethylhexyloxyphenol methoxyphenyl triazine, and 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine. More preferably, it is at least one selected from the group consisting of 2-ethylhexyl paramethoxycinnamate, diethylaminohydroxybenzoylhexylbenzoate, and bisethylhexyloxyphenol methoxyphenyl triazine.

When component (e) is used in the skin topical preparation of the present invention, the content of the component (e) in the skin topical preparation is preferably 0.2% by mass or more, more preferably 1% by mass or more, even more preferably 3% by mass or more, and even more preferably 5% by mass or more, from the viewpoint of imparting an excellent ultraviolet protection effect. In addition, from the viewpoint of obtaining an excellent infrared protection effect and from the viewpoint of preventing the skin topical preparation from becoming white when applied to the skin and obtaining a natural color, the content 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 content of component (e) in the skin topical preparation is preferably 0.2% by mass or more and 30% by mass or less, more preferably 1% by mass or more and 25% by mass or less, even more preferably 3% by mass or more and 20% by mass or less, and even more preferably 5% by mass or more and 15% by mass or less.

In the skin topical preparation of the present invention, the mass ratio [{(a)+(b)+(c)}/(e)] of the total amount of ingredients (a)-(c) to ingredient (e) is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.3 or more, from the viewpoint of obtaining an excellent infrared protection effect and from the viewpoint of preventing the skin topical preparation from becoming white when applied to the skin and obtaining a natural color. Also, from the viewpoint of imparting an excellent ultraviolet protection effect, it is preferably 5 or less, more preferably 3 or less, even more preferably 1 or less, and even more preferably 0.5 or less. The specific range of the mass ratio [{(a)+(b)+(c)}/(e)] is preferably 0.1 or more and 5 or less, more preferably 0.1 or more and 3 or less, even more preferably 0.2 or more and 1 or less, even more preferably 0.3 or more and 1 or less, and even more preferably 0.3 or more and 0.5 or less.

<Component (f): Oil>
From the viewpoint of dispersing the components (a) to (c) and dispersing or dissolving other blended components to improve the applicability to the skin, and from the viewpoint of preparing an oil-in-water or water-in-oil type skin topical preparation, it is preferable that the skin topical preparation of the present invention further contains an oil as component (f). As the oil, both the non-volatile oil (f1) and the volatile oil (f2) other than the component (e) can be used, and these can also be used in combination. When an oil-soluble ultraviolet absorbing agent is used as the component (e) in the skin topical preparation of the present invention, it is preferable that the oil (f) contains at least a non-volatile oil (f1) from the viewpoint of dissolving it.

(Non-volatile oil (f1))
The skin topical preparation of the present invention preferably contains a non-volatile oil (f1) as the oil (f). The non-volatile oil refers to an oil whose evaporation amount at 25° C. in 6 hours is less than 20%, 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 (f1) is preferably liquid at 1 atmosphere and 25° C. More specifically, component (f1) 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 (f1) include non-volatile oils other than component (e) 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 viewpoint of obtaining a natural color when applied to the skin and suppressing 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) (for example, 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.

From the viewpoint of suppressing stickiness when applied to the skin, component (f1) is preferably one or more types selected from the group consisting of ester oils, silicone oils, and hydrocarbon oils, more preferably one or more types selected from the group consisting of ester oils and hydrocarbon oils, and even more preferably one or more types selected from the group consisting of alkyl benzoates (C12-15), isopropyl palmitate, and light liquid isoparaffin, among non-volatile oils that are liquid at 25°C.

When the skin topical preparation of the present invention contains component (f1), the content is preferably 1% by mass or more, more preferably 4% by mass or more, and even more preferably 8% by mass or more from the viewpoint of dispersing components (a) to (c) and dispersing or dissolving other blended components to improve application to the skin, and from the viewpoint of preparing an oil-in-water type or water-in-oil type skin topical preparation. In addition, from the viewpoint of obtaining an excellent infrared protection effect and from the viewpoint of suppressing stickiness when applied to the skin, it is preferably 99% by mass or less, more preferably 90% by mass or less, even more preferably 80% by mass or less, even more preferably 50% by mass or less, and even more preferably 30% by mass or less. The specific range of the content of component (f1) in the skin topical preparation is preferably 1% by mass or more and 99% by mass or less, more preferably 4% by mass or more and 90% by mass or less, even more preferably 8% by mass or more and 80% by mass or less, even more preferably 8% by mass or more and 50% by mass or less, and even more preferably 8% by mass or more and 30% by mass or less.

When the topical skin preparation of the present invention contains component (f1), the mass ratio of the total amount of components (a) to (c) to component (f1) [{(a) + (b) + (c)}/(f1)] is preferably 0.01 or more, more preferably 0.05 or more, and even more preferably 0.1 or more, from the viewpoint of obtaining an excellent infrared protection effect and from the viewpoint of preventing the topical skin preparation from turning white when applied to the skin and obtaining a natural color, and is preferably 10 or less, more preferably 5 or less, even more preferably 3 or less, still more preferably 1 or less, and even more preferably 0.5 or less, from the viewpoint of dissolving an oil-soluble ultraviolet absorber, improving applicability, and preparing an oil-in-water or water-in-oil type topical skin preparation. The specific range of the mass ratio [{(a)+(b)+(c)}/(f1)] is preferably 0.01 or more and 10 or less, more preferably 0.01 or more and 5 or less, even more preferably 0.05 or more and 3 or less, even more preferably 0.1 or more and 1 or less, and even more preferably 0.3 or more and 0.5 or less.

When the skin topical preparation of the present invention contains component (e) and component (f1), the mass ratio [(e)/(f1)] is preferably 0.01 or more, more preferably 0.02 or more, even more preferably 0.05 or more, and even more preferably 0.1 or more, from the viewpoint of obtaining an excellent ultraviolet protection effect, and when an oil-soluble ultraviolet absorber is used as component (e), from the viewpoint of its solubility, it is preferably 10 or less, more preferably 5 or less, and even more preferably 3 or less. The specific range of the mass ratio [(e)/(f1)] is preferably 0.01 or more and 10 or less, more preferably 0.02 or more and 5 or less, even more preferably 0.05 or more and 3 or less, and even more preferably 0.1 or more and 3 or less.

(Volatile oil (f2))
In this specification, the volatile oil refers to an oil agent other than the above-mentioned ultraviolet absorbent (e), which has an evaporation amount of 20% or more at 25°C in 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.

Component (f2) 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 (f2) from the viewpoint of suppressing stickiness when applied to the skin, and decamethylcyclopentasiloxane is more preferred.

Commercially available volatile silicone oils that can be used as component (f2) 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 "DOWSIL SH200C Fluid 1cs" (octamethyltrisiloxane), "DOWSIL SH200C Fluid 1.5cs" (decamethyltetrasiloxane), and "DOWSIL SH200C Fluid 2.5cs" (decamethyltetrasiloxane), manufactured by Dow Toray Co., Ltd. Fluid 2cs (dodecamethylpentasiloxane), DOWSIL SH245 Fluid (decamethylcyclopentasiloxane), and Momentive Performance Materials' TSF405 (decamethylcyclopentasiloxane).

When the topical skin preparation of the present invention contains component (f2), its content can be appropriately selected depending on the formulation of the topical skin preparation, but it can be preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. In addition, from the viewpoint of suppressing stickiness when applied to the skin, it can be preferably 85% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less. The specific range of the content of component (f2) in the topical skin preparation is preferably 1% by mass or more and 85% by mass or less, more preferably 5% by mass or more and 80% by mass or less, and even more preferably 10% by mass or more and 75% by mass or less.

(aqueous medium)
The topical skin preparation of the present invention may further contain an aqueous medium as necessary from the viewpoint of dispersing or dissolving the components (a) to (c) and other blended components, and from the viewpoint of preparing an oil-in-water or water-in-oil type topical skin preparation. The aqueous medium is not particularly limited as long as it can disperse or dissolve the components (a) to (c) 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.

When an aqueous medium is contained in the topical skin preparation, its content can be appropriately selected depending on the formulation of the topical skin preparation, but it is preferably 5% by mass or more, more preferably 8% by mass or more, and even more preferably 10% by mass or more. It is also preferably 99% 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.

<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 surfactants, ultraviolet scattering agents, antiperspirants, fragrances, moisturizers, thickeners, bactericides, pH adjusters, antioxidants, preservatives, etc.

(Method of manufacturing topical skin preparation)
The method for producing the topical skin preparation of the present invention is not particularly limited, and a known method can be appropriately used depending on the formulation of the topical skin preparation. For example, the components (a) to (c) and all other components are mixed together and mixed uniformly with a homogenizer, a disperser, etc. When an aqueous medium is added, it is also possible to use a method in which all components other than the aqueous medium are mixed together and mixed uniformly with a disperser, etc., and then the aqueous medium is added and further stirred and mixed with a homogenizer, etc.

[How to protect your skin from infrared rays]
The present invention also provides a method for protecting the skin from infrared 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. When the infrared protection rate at a wavelength of 1500 nm is within the above range, 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 external skin preparation of the present invention to the skin, it is possible to effectively protect the skin from infrared rays.

In relation to the above-mentioned embodiment, the present invention further discloses the following embodiments.
＜1＞
The following components (a) to (c):
(a) a plate-like metal oxide having a thickness of 100 nm or more and 120 nm or less;
(b) a plate-like metal oxide having a thickness of 125 nm or more and 145 nm or less, and (c) a plate-like metal oxide having a thickness of 180 nm or more and 200 nm or less;
It is made by blending
The skin topical preparation has a total amount of the components (a) to (c) of 100% by mass, in which the amount of component (a) is 5% by mass or more and 70% by mass or less, the amount of component (b) is 15% by mass or more and 75% by mass or less, and the amount of component (c) is 5% by mass or more and 70% by mass or less.
＜2＞
The external skin preparation according to <1>, wherein the plate-like metal oxide is preferably at least one selected from the group consisting of plate-like titanium oxide and plate-like zinc oxide, and more preferably plate-like titanium oxide.
＜3＞
The skin external preparation according to <1> or <2>, wherein the plate-like metal oxide is surface-treated with at least one selected from the group consisting of silicone and alkylalkoxysilane, more preferably at least one selected from the group consisting of methylpolysiloxane, dimethylpolysiloxane, methylhydrogenpolysiloxane, (alkyl acrylate/dimethicone) copolymer, and octyltriethoxysilane.
＜4＞
The external skin preparation according to any one of <1> to <3>, wherein the thickness of the component (a) is preferably 105 nm or more and 115 nm or less, the thickness of the component (b) is preferably 130 nm or more and 140 nm or less, and the thickness of the component (c) is preferably 185 nm or more and 195 nm or less.
＜5＞
The external skin preparation according to any one of <1> to <4>, wherein the average particle size of the components (a) to (c) is preferably 1 μm or more and 20 μm or less, more preferably 2 μm or more and 15 μm or less, even more preferably 2 μm or more and 12 μm or less, still more preferably 3 μm or more and 10 μm or less, and still more preferably 5 μm or more and 10 μm or less.
＜6＞
The external skin preparation according to any one of <1> to <5>, wherein the aspect ratio of the components (a) to (c) is preferably 10 or more and 200 or less, more preferably 10 or more and 150 or less, even more preferably 10 or more and 100 or less, still more preferably 20 or more and 100 or less, still more preferably 30 or more and 100 or less, and still more preferably 35 or more and 90 or less.
＜７＞
The topical skin preparation according to any one of <1> to <6>, wherein the blending ratios of the components (a), (b) and (c) relative to 100% by mass of the total blending amount of the components (a) to (c) satisfy the following condition 1, and preferably further satisfy the following condition 2.
Condition 1: In a three-phase diagram showing the mass% of components (a), (b), and (c) relative to 100 mass% of the total amount of components (a) to (c), the blending ratio of each component is within the range of a composition region surrounded by six composition points shown below.
(a, b, c) = (70, 15, 15), (28, 26, 46), (5, 40, 55), (5, 67, 28), (20, 68, 12), (57, 33, 10)
Condition 2: In a three-phase diagram showing the mass% of components (a), (b), and (c) relative to 100 mass% of the total amount of components (a) to (c), the blending ratio of each component is within the range of a composition region surrounded by six composition points shown below.
(a, b, c) = (50, 28, 22), (25, 45, 30), (25, 32, 43), (15, 43, 42), (23, 55, 22), (42, 43, 15)
＜8＞
The topical skin preparation according to any one of <1> to <7>, wherein the total amount of the components (a) to (c) in the topical skin preparation is preferably 1% by mass or more and 35% by mass or less, more preferably 1% by mass or more and 25% by mass or less, even more preferably 1% by mass or more and 20% by mass or less, still more preferably 1% by mass or more and 15% by mass or less, still more preferably 1.5% by mass or more and 10% by mass or less, and still more preferably 2% by mass or more and 10% by mass or less.

＜9＞
The external skin preparation according to any one of <1> to <8>, further comprising a feel improver as a component (d).
＜10＞
The topical skin preparation according to <9>, wherein the component (d) is preferably spherical inorganic particles, more preferably spherical metal oxide particles, even more preferably one or more particles selected from the group consisting of spherical titanium oxide particles and spherical zinc oxide particles, and still more preferably spherical titanium oxide particles.
<11>
The external skin preparation according to <9> or <10>, wherein the average particle size of the particles used as the component (d) is preferably 0.1 μm or more and 10 μm or less, more preferably 0.2 μm or more and 5 μm or less, and even more preferably 0.5 μm or more and 2 μm or less.
＜12＞
The external skin preparation according to any one of <9> to <11>, wherein the content of the component (d) is preferably 1% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, even more preferably 1% by mass or more and 10% by mass or less, still more preferably 1.5% by mass or more and 10% by mass or less, and still more preferably 2% by mass or more and 10% by mass or less.
＜13＞
The external skin preparation according to any one of <9> to <12>, wherein the mass ratio of the total amount of the components (a) to (c) to the component (d), [{(a)+(b)+(c)}/(d)], is preferably 0.1 or more and 5 or less, more preferably 0.2 or more and 3 or less, even more preferably 0.5 or more and 2 or less, and still more preferably 0.5 or more and 1.5 or less.
＜14＞
The external skin preparation according to any one of <1> to <13>, further comprising an ultraviolet absorber as a component (e).
＜15＞
The component (e) is preferably an oil-soluble organic ultraviolet absorber, and more preferably a compound 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. The skin external preparation according to <14>, wherein the one or more 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 is preferable, and the one or more selected from the group consisting of 2-ethylhexyl paramethoxycinnamate, diethylamino hydroxybenzoyl hexyl benzoate, and bisethylhexyloxyphenol methoxyphenyl triazine is more preferable.
＜16＞
The content of the component (e) in the topical skin preparation of <14> or <15> is preferably 0.2% by mass or more and 30% by mass or less, more preferably 1% by mass or more and 25% by mass or less, even more preferably 3% by mass or more and 20% by mass or less, and still more preferably 5% by mass or more and 15% by mass or less.
＜１７＞
The external skin preparation according to any one of <14> to <16>, wherein the mass ratio of the total amount of the components (a) to (c) to the component (e), [{(a)+(b)+(c)}/(e)], is preferably 0.1 or more and 5 or less, more preferably 0.1 or more and 3 or less, even more preferably 0.2 or more and 1 or less, still more preferably 0.3 or more and 1 or less, and still more preferably 0.3 or more and 0.5 or less.
＜18＞
The external skin preparation according to any one of <1> to <17>, further comprising an oil as a component (f), preferably a non-volatile oil (f1).
＜19＞
The external skin preparation of <18>, wherein the component (f1) is one or more selected from the group consisting of ester oils, silicone oils, hydrocarbon oils, higher fatty acids, and higher alcohols, more preferably one or more selected from the group consisting of ester oils, silicone oils, and hydrocarbon oils, even 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.
＜20＞
The topical skin preparation of <18> or <19>, wherein the content of the component (f1) is preferably 1% by mass or more and 99% by mass or less, more preferably 4% by mass or more and 90% by mass or less, even more preferably 8% by mass or more and 80% by mass or less, still more preferably 8% by mass or more and 50% by mass or less, and still more preferably 8% by mass or more and 30% by mass or less.
＜21＞
The external skin preparation according to any one of <18> to <20>, wherein the mass ratio of the total amount of the components (a) to (c) to the component (f1), [{(a)+(b)+(c)}/(f1)], is preferably 0.01 or more and 10 or less, more preferably 0.01 or more and 5 or less, even more preferably 0.05 or more and 3 or less, still more preferably 0.1 or more and 1 or less, and still more preferably 0.3 or more and 0.5 or less.
＜22＞
The external skin preparation according to any one of <18> to <21>, wherein the mass ratio [(e)/(f1)] is preferably 0.01 or more and 10 or less, more preferably 0.02 or more and 5 or less, even more preferably 0.05 or more and 3 or less, and still more preferably 0.1 or more and 3 or less.
＜23＞
The external skin preparation according to any one of <18> to <22>, containing as component (f) a volatile oil (f2), preferably a volatile silicone oil, more preferably a linear organopolysiloxane or a cyclic organopolysiloxane which is liquid at 25°C and volatile, even more preferably a cyclic organopolysiloxane, still more preferably a 4- to 6-membered cyclic siloxane having an alkyl group having from 1 to 5 carbon atoms as a substituent, and even more preferably decamethylcyclopentasiloxane.
＜24＞
The content of the component (f2) in the topical skin preparation according to <23> is preferably 1% by mass or more and 85% by mass or less, more preferably 5% by mass or more and 80% by mass or less, and even more preferably 10% by mass or more and 75% by mass or less.

＜25＞
An external skin preparation comprising the following components (a) to (c):
(a) plate-shaped titanium oxide having a thickness of 100 nm or more and 120 nm or less;
(b) plate-like titanium oxide having a thickness of 125 nm or more and 145 nm or less, and (c) plate-like titanium oxide having a thickness of 180 nm or more and 200 nm or less,
It is made by blending
The average particle size of the components (a) to (c) is 3 μm or more and 10 μm or less,
the amount of component (a) is from 5% by mass to 70% by mass, the amount of component (b) is from 15% by mass to 75% by mass, and the amount of component (c) is from 5% by mass to 70% by mass, relative to 100% by mass of the total amount of components (a) to (c);
The skin topical preparation, wherein the total amount of components (a) to (c) in the skin topical preparation is 2% by mass or more and 10% by mass or less.
＜26＞
An external skin preparation comprising the following components (a) to (c):
(a) plate-shaped titanium oxide having a thickness of 100 nm or more and 120 nm or less;
(b) plate-like titanium oxide having a thickness of 125 nm or more and 145 nm or less, and (c) plate-like titanium oxide having a thickness of 180 nm or more and 200 nm or less,
It is made by blending
The average particle size of the components (a) to (c) is 3 μm or more and 10 μm or less,
The blending ratios of the components (a), (b) and (c) relative to the total blending amount of the components (a) to (c) (100 mass %) satisfy the following condition 1,
The skin topical preparation, wherein the total amount of components (a) to (c) in the skin topical preparation is 2% by mass or more and 10% by mass or less.
Condition 1: In a three-phase diagram showing the mass% of components (a), (b), and (c) relative to 100 mass% of the total amount of components (a) to (c), the blending ratio of each component is within the range of a composition region surrounded by six composition points shown below.
(a, b, c) = (70, 15, 15), (28, 26, 46), (5, 40, 55), (5, 67, 28), (20, 68, 12), (57, 33, 10)
＜27＞
An external skin preparation comprising the following components (a) to (c):
(a) plate-shaped titanium oxide having a thickness of 100 nm or more and 120 nm or less;
(b) plate-like titanium oxide having a thickness of 125 nm or more and 145 nm or less, and (c) plate-like titanium oxide having a thickness of 180 nm or more and 200 nm or less,
It is made by blending
The average particle size of the components (a) to (c) is 3 μm or more and 10 μm or less,
the blending ratios of the components (a), (b) and (c) relative to 100 mass% of the total blending amount of the components (a) to (c) satisfy the following condition 2,
The skin topical preparation, wherein the total amount of components (a) to (c) in the skin topical preparation is 2% by mass or more and 10% by mass or less.
Condition 2: In a three-phase diagram showing the mass% of components (a), (b), and (c) relative to 100 mass% of the total amount of components (a) to (c), the blending ratio of each component is within the range of a composition region surrounded by six composition points shown below.
(a, b, c) = (50, 28, 22), (25, 45, 30), (25, 32, 43), (15, 43, 42), (23, 55, 22), (42, 43, 15)
＜28＞
Further, the composition contains, as a component (d), 2% by mass or more and 10% by mass or less of one or more feel improvers selected from the group consisting of spherical titanium oxide particles and spherical zinc oxide particles,
Contains 5% by mass or more and 15% by mass or less of an oil-soluble organic ultraviolet absorber as component (e);
The external skin preparation according to any one of <25> to <27>, comprising, as a component (f), 8% by mass or more and 50% by mass or less of one or more non-volatile oils (f1) selected from the group consisting of ester oils and hydrocarbon oils.
＜29＞
The external skin preparation according to any one of <1> to <28>, which is in the form of a liquid, a gel, or a cream.
＜30＞
The external skin preparation according to any one of <1> to <29>, which is a skin cosmetic, and is preferably a sunscreen cosmetic, a suntan cosmetic, or a makeup base cosmetic.
＜31＞
A method for protecting the skin from infrared rays, comprising applying to the skin any one of the above-mentioned external preparations for skin <1> to <30>.
＜32＞
The method according to <31>, wherein the infrared protection rate at a wavelength of 1,500 nm is preferably 10% or more, more preferably 12% or more, and even more preferably 15% or more.

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.

(Thickness Measurement)
The thickness of the plate-like titanium oxide used as components (a) to (c) was determined by observing components (a) to (c) 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, measuring the thickness of 50 particles in the observed image, and calculating the average value per number.

(Measurement of average particle size and aspect ratio)
The average particle size of the plate-like titanium oxide used as components (a) to (c) and the spherical titanium oxide used as component (d) was determined as the median diameter (D50) measured in an aqueous dispersion using a laser diffraction/scattering particle size distribution analyzer ("LA920" manufactured by HORIBA, Ltd.) with a relative refractive index of 2.0 and a particle size reference volume.
The aspect ratio of the plate-like titanium oxide used as components (a) to (c) was calculated from (average particle size/thickness).

[Evaluation (1): Infrared protection rate, color when applied to skin, and overall evaluation]
(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.

(Color when applied to skin)
Each skin topical preparation was applied at 2 mg/ ^cm2 to two locations on the forearms of four subjects, and the color immediately after application was evaluated on a 10-point scale in 0.5 increments according to the following evaluation criteria, with 1 point being very poor and 5 points being very good. Evaluations were performed by two expert panelists, and the average score (rounded off to the nearest tenth) was used as the evaluation score.
<Evaluation criteria>
1: Very bad 2: Bad 3: Neither good nor bad 4: Good 5: Very good

(comprehensive evaluation)
In the evaluation results shown in Table 1, a color evaluation score of 3.6 or more when applied to the skin was rated as rank A, a score of 3.0 to 3.5 was rated as rank B, a score of 2.5 to 2.9 was rated as rank C, and a score of 2.4 or less was rated as rank D. Furthermore, the infrared protection rate of 15% or more was increased by one rank, and the infrared protection rate of less than 15% was decreased by one rank, and the results are shown in Table 1 as an overall evaluation. The overall evaluation was made on a 6-level scale of A+, A, B, C, D, and D-.

[Evaluation (2): Color and Transparency]
When each example of the topical skin preparation was applied to the skin, it was evaluated by the following method as to whether it had a natural coloring and did not appear unnatural, such as being biased toward red, blue, or green, or being whitish without transparency.
The skin topical preparation was applied at 2 mg/ ^cm2 to four areas of the forearm with different skin tones, and the color and transparency were visually observed and evaluated on a 10-point scale with 0.5 point increments according to the following evaluation criteria. Evaluation was performed by two expert panelists, and the average score (rounded to the nearest tenth) was used as the evaluation score.
For the four categories of reddish, bluish, greenish, and transparency, a sample was rated as passing if there were no items with an evaluation score of less than 2.0 and two or more items with an evaluation score of 3.0 or more, and otherwise was rated as failing.
<Evaluation criteria>
(Reddish)
5: Little redness 4: Slightly less redness 3: Neither 2: Slightly more redness 1: Very redness (bluish)
5: Less blue 4: Slightly less blue 3: Neither 2: Slightly more blue 1: Very blue (greenish)
5: Little green 4: Slightly less green 3: Neither 2: Slightly more green 1: Very more green (transparency)
5: Transparent 4: Slightly transparent 3: Neither 2: Slightly opaque 1: Opaque

Production Example 1 (Production of Plate-like Titanium Oxide 1)
Untreated plate-like titanium oxide ("Featheleve PT-7401K" manufactured by CQV Corporation, thickness 112 nm, aspect ratio 126, average particle size 14.1 μm) was pulverized using a fine pulverizer with an impact classifier built in ("ACM-10" manufactured by Hosokawa Micron Corp.), and then coated with an (alkyl acrylate/dimethicone) copolymer to obtain plate-like titanium oxide 1 having a thickness of 112 nm, an aspect ratio of 80, and an average particle size of 9.0 μm.

Production Example 2 (Production of Plate-like Titanium Oxide 2)
Except for using "Featheleve PT-7801K" manufactured by CQV Corporation (thickness: 134 nm, aspect ratio: 95, average particle size: 12.8 μm) instead of "Featheleve PT-7401K" manufactured by CQV Corporation as the untreated plate-like titanium oxide, the same treatment as in Production Example 1 was carried out to obtain plate-like titanium oxide 2 having a thickness of 134 nm, an aspect ratio of 64, and an average particle size of 8.6 μm.

Production Example 3 (Production of Plate-like Titanium Oxide 3)
The same treatment as in Production Example 1 was carried out, except that "Featheleve PT-7901K" manufactured by CQV Corporation (thickness: 191 nm, aspect ratio: 58, average particle size: 11.1 μm) was used as the untreated plate-like titanium oxide instead of "Featheleve PT-7401K" manufactured by CQV Corporation, to obtain plate-like titanium oxide 3 having a thickness of 191 nm, an aspect ratio of 44, and an average particle size of 8.5 μm.

Examples 1 to 12 and Comparative Examples 1 to 8 (Production and Evaluation of Skin Topical Preparations)
The components shown in Table 1 were blended and mixed uniformly using a homogenizer to produce topical skin preparations having the compositions shown in Table 1. The obtained topical skin preparations were evaluated using the methods described above. The results are shown in Table 1. The blending amounts shown in Table 1 are the active ingredient amounts (mass%) of each component.

The ingredients in Table 1 are as follows.
*1: Plate-shaped titanium oxide 1 obtained in Production Example 1
*2: Plate-shaped titanium oxide 2 obtained in Production Example 2
*3: Plate-shaped titanium oxide 3 obtained in Production Example 3
*4: "ST-750EC" manufactured by Titanium Industries Co., Ltd., spherical titanium oxide, average particle size 1000 nm, aspect ratio 1.0
*5: BASF "Ubinal MC80", 2-ethylhexyl paramethoxycinnamate *6: Kao Corporation "Exepar IPP", isopropyl palmitate *7: Momentive Performance Materials "TSF405", decamethylcyclopentasiloxane

As can be seen from Table 1, the topical skin preparations of Examples 1 to 12 are able to achieve both an infrared protection effect and a natural color when applied to the skin. Among them, Examples 1, 3, 4, 6, 8, and 9, in which the blending ratios of components (a) to (c) satisfy the above-mentioned condition 1, are more preferable with an overall rating of A or higher, and Examples 4 and 6, which satisfy the above-mentioned condition 2, are even more preferable with an overall rating of A+.
In contrast, the skin topical preparations of Comparative Examples 1 to 8 did not provide sufficient effect in at least one of the infrared protection effect and the natural color when applied to the skin.

The notations A+, A, B, C, D, and D- in the three-phase diagram in Figure 1 indicate the above-mentioned overall evaluation at the composition points of components (a) to (c) corresponding to the skin topical preparations of Examples 1 to 12 and Comparative Examples 1 to 8.

The skin topical preparation of the present invention has excellent infrared protection effects, and when applied to the skin, it is unlikely to produce a reddish or bluish tinge, and can achieve a natural color that blends in with the skin color, making it useful, for example, as a skin cosmetic.

1. Composition region where the amount of component (a) is 5% by mass or more and 70% by mass or less, the amount of component (b) is 15% by mass or more and 75% by mass or less, and the amount of component (c) is 5% by mass or more and 70% by mass or less, relative to 100% by mass of the total amount of components (a) to (c). 2. Composition region where condition 1 is satisfied. 3. Composition region where condition 2 is satisfied.

Claims (7)

The following components (a) to (c):
(a) a plate-like metal oxide having a thickness of 100 nm or more and 120 nm or less;
(b) a plate-like metal oxide having a thickness of 125 nm or more and 145 nm or less, and (c) a plate-like metal oxide having a thickness of 180 nm or more and 200 nm or less;
It is made by blending
the amount of component (a) is from 5% by mass to 70% by mass, the amount of component (b) is from 15% by mass to 75% by mass, and the amount of component (c) is from 5% by mass to 70% by mass, relative to 100% by mass of the total amount of components (a) to (c);
The total amount of the components (a) to (c) is 1% by mass or more and 35% by mass or less,
The infrared ray protective external skin preparation, wherein the plate-like metal oxide is plate-like titanium oxide . 2. The infrared ray protective external skin preparation according to claim 1 , wherein the average particle size of the components (a) to (c) is 1 μm or more and 20 μm or less. 3. The infrared ray protective skin preparation according to claim 1, further comprising a feel improver as component (d). The infrared ray protective skin external preparation according to any one of claims 1 to 3 , further comprising an ultraviolet ray absorber as component (e). The infrared ray protective skin preparation for external use according to any one of claims 1 to 4 , further comprising an oil as component (f). The infrared ray protective external skin preparation according to any one of claims 1 to 5 , which is a skin cosmetic. A method for protecting the skin from infrared rays , comprising applying the infrared ray protection skin topical preparation according to any one of claims 1 to 6 to the skin.