WO2022239842A1

WO2022239842A1 - Skin external agent

Info

Publication number: WO2022239842A1
Application number: PCT/JP2022/020110
Authority: WO
Inventors: 大輝高橋
Original assignee: 花王株式会社
Priority date: 2021-05-14
Filing date: 2022-05-12
Publication date: 2022-11-17
Also published as: JP2022176168A; TW202310823A; CN117042746A

Abstract

This skin external agent contains: a component (A) which is at least one metal oxide selected from the group consisting of a spherical metal oxide (A1) having an average particle diameter of 350-2,500 nm and a plate-shaped metal oxide (A2); and a component (B) which is a nonvolatile oil, wherein the content of the component (A) in said skin external agent is 2-50 mass%, and the viscosity at 25ºC is at least 2,500 mPa∙s.

Description

Skin topical agent

The present invention relates to an external preparation for skin.

From the viewpoint of skin protection against sunlight, UV protection cosmetics such as sunscreen cosmetics are known. On the other hand, in recent years, due to the heightened awareness of health, there is a demand for an external preparation for skin that has a protective function against infrared rays.
Regarding skin preparations for external use having an infrared protection function, for example, Patent Document 1 (International Publication No. 2009/017104) discloses that infrared rays are prevented from reaching tissues deeper than skin tissues, and infrared rays protect those tissues. As a technique related to an inhibitor for preventing damage, an agent for preventing near-infrared damage to living tissue containing an infrared transmission shielding agent consisting of titanium oxide powder and zinc oxide powder has been disclosed. Patent Document 2 (Japanese Patent Application Laid-Open No. 2017-95361) discloses a near-infrared protective cosmetic composition composed of titanium oxide powder and zinc oxide powder, which achieves both excellent near-infrared protective effect and high transparency. ing.
In addition, Patent Document 3 (International Publication No. 2020/138431), Patent Document 4 (JP 2020-105175), Patent Document 5 (JP 2020-105176) and Patent Document 6 (JP 2020-105177) Publication) discloses an external preparation for skin containing a plate-like metal oxide having a predetermined shape as an external preparation for skin having a more excellent infrared protection effect.

The present invention relates to the following.
[1] Component (A): one or more metal oxides selected from the group consisting of spherical metal oxides (A1) and plate-like metal oxides (A2) having an average particle size of 350 nm or more and 2,500 nm or less, and a component (B): non-volatile oil,
wherein the content of component (A) in the external skin preparation is 2% by mass or more and 50% by mass or less, and the viscosity at 25°C is 2,500 mPa·s or more. External agent.
[2] A method for protecting the skin from infrared radiation, which comprises applying the external preparation for skin according to [1] to the skin.

10 is an IR microscope observation photograph (score 5) in evaluation of coating film uniformity of the external preparation for skin of Example 9. FIG. 4 is an IR microscope observation photograph (score 1) in evaluation of coating film uniformity of the external preparation for skin of Comparative Example 2. FIG.

Detailed description of the invention

[External preparation for skin]
The skin external preparation of the present invention is
Component (A): one or more metal oxides selected from the group consisting of spherical metal oxides (A1) and plate-like metal oxides (A2) having an average particle size of 350 nm or more and 2,500 nm or less, and component (B) : non-volatile oil,
wherein the content of component (A) in the external skin preparation is 2% by mass or more and 50% by mass or less, and the viscosity at 25°C is 2,500 mPa·s or more.
The external preparation for skin of the present invention having the above-described constitution is excellent in the protective effect against ultraviolet rays, infrared rays, etc., and produces less whitening when applied to the skin.

In order to protect the skin against sunlight, there is a demand for an external preparation for skin that has further improved protection against ultraviolet rays, infrared rays, and the like. Furthermore, external skin preparations are also required to be less likely to turn white when applied to the skin (hereinafter also referred to as “whitening”).
An object of the present invention is to provide an external preparation for skin which has excellent protective effect against ultraviolet rays, infrared rays, etc., and which causes less whitening when applied to the skin.

The present inventor found that an external preparation for skin containing a predetermined shape, a predetermined amount of metal oxide, and a non-volatile oil and having a viscosity of a predetermined value or more can solve the above problems.

According to the present invention, it is possible to provide an external preparation for skin that has excellent protective effects against ultraviolet rays, infrared rays, etc., and that leaves little whitening when applied to the skin. When the external preparation for skin is applied to the skin, it can protect the skin from ultraviolet rays, infrared rays, and the like, and can also provide an effect of suppressing an increase in skin temperature and an effect of suppressing fatigue due to sunlight irradiation.

Although the reason why the external preparation for skin of the present invention provides the above effects is not clear, it is considered as follows.
It is known that skin preparations containing metal oxides such as titanium oxide with a larger particle size are more effective in protecting against ultraviolet rays and infrared rays. However, simply using a metal oxide having a large particle size limits the improvement in the infrared protection effect. In addition, for example, when a spherical metal oxide having a large particle size is added to an external preparation for skin, visible light is scattered on the surface of the particles when applied to the skin, which tends to cause whitening. Therefore, it has been difficult to simultaneously improve the protective effect against ultraviolet rays, infrared rays, etc. and suppress whitening when applied to the skin, simply by adjusting the particle size of the metal oxide used.
In addition, increasing the content of metal oxides in external preparations for skin can also improve the protective effect against ultraviolet rays, infrared rays, etc. However, it is said that when the content is increased, whitening tends to occur when applied to the skin. There was also a tendency

By using a predetermined amount of metal oxide having a predetermined size and shape as the component (A), the external preparation for skin of the present invention has a protective effect against ultraviolet rays, infrared rays, etc., and suppresses whitening when applied to the skin. is also possible. Furthermore, in order to further improve the protective effect against ultraviolet rays, infrared rays, etc., in external preparations for skin containing metal oxides, the present inventors have found that the uniform applicability of the external preparations for skin, in particular, the ability to protect against ultraviolet rays, infrared rays, etc. It has been found that it is effective to evenly dispose the active ingredient (A) on the skin surface, and that rheological control of the external preparation for skin is important for this purpose.
Specifically, when a low-viscosity topical skin preparation is applied to the skin, component (A), which has a high specific gravity, is unlikely to be retained in the coating film, so component (A) is likely to settle in the sulcus cutis. be done. In particular, component (A), which has a large particle size, tends to settle in the sulcus cutis and cannot be distributed uniformly on the skin surface, and is considered to reduce the protective effect against ultraviolet rays, infrared rays, and the like.
The external preparation for skin of the present invention contains a non-volatile oil as component (B) in addition to component (A), and has a viscosity of a predetermined value or more, so that when applied to the skin, the skin groove of component (A) is reduced. Presumably, the sedimentation to the surface can be suppressed, and the uniform coating property can be improved, so that the protective effect against ultraviolet rays, infrared rays, etc. can be further enhanced.

<Definition>
In the present invention, ultraviolet light means electromagnetic waves with a wavelength of 200 to 360 nm, and infrared light means electromagnetic waves with a wavelength of 780 nm to 1 mm. Among these, the external preparation for skin of the present invention is particularly excellent in the near-infrared protective effect with a wavelength of 780 nm to 2500 nm. Due to this near-infrared protection effect, it is possible to obtain an effect of suppressing an increase in skin temperature due to sunlight irradiation and an effect of suppressing fatigue.
In this specification, the infrared protection rate at a wavelength of 825 nm is used as an indicator of the infrared protection effect.

<Viscosity>
The skin preparation for external use of the present invention is applied at 25° C. from the viewpoint of improving uniform applicability, suppressing precipitation of component (A) in the skin grooves when applied to the skin, and improving the protective effect against ultraviolet rays, infrared rays, and the like. The viscosity at the That's it. In addition, from the viewpoint of ease of application to the skin, it is preferably 200,000 mPa·s or less, more preferably 150,000 mPa·s or less, even more preferably 100,000 mPa·s or less, and even more preferably 50,000 mPa·s or less. s or less, more preferably 30,000 mPa·s or less, and even more preferably 20,000 mPa·s or less.
The viscosity of the external preparation for skin of the present invention at 25° C. is 2,500 mPa·s or more, preferably 2,500 mPa·s or more and 200,000 mPa·s or less, more preferably 3,000 mPa·s or more and 200 mPa·s or more. 000 mPa s or less, more preferably 5,000 mPa s or more and 150,000 mPa s or less, even more preferably 8,000 mPa s or more and 100,000 mPa s or less, still more preferably 8,000 mPa s or more50, 000 mPa·s or less, more preferably 10,000 mPa·s or more and 30,000 mPa·s or less. In another embodiment, the viscosity of the external preparation for skin of the present invention at 25° C. is preferably 2,500 mPa·s or more and 150,000 mPa·s or less, more preferably 2,500 mPa·s or more and 100,000 mPa·s or less. It is preferably 2,500 mPa s or more and 50,000 mPa s or less, still more preferably 2,500 mPa s or more and 30,000 mPa s or less, still more preferably 2,500 mPa s or more and 20,000 mPa s or less. .
The viscosity of the external preparation for skin at 25°C is a value measured at 25°C using a Brookfield viscometer, and can be specifically measured by the method described in Examples.

Means for adjusting the viscosity of the external preparation for skin of the present invention within the above range include selecting the type and content of component (A) used in the external preparation for skin, selecting the type and content of component (B), and increasing the viscosity described later. Selection of the use and content of viscosity agents, emulsifiers, dispersants, aqueous media, etc., and selection of dispersion methods for component (A) are included.

<Dosage type, etc.>
The dosage form of the external preparation for skin of the present invention is not particularly limited as long as the viscosity is within the above range, and from the viewpoint of ease of application to the skin, it is preferably liquid, gel or cream. As long as the viscosity is within the above range, the dosage form of the external skin preparation of the present invention is preferably a solid form such as a stick preparation from the viewpoint of infrared protection. The external preparation for skin may be a non-aqueous composition or an emulsified composition, and the emulsified composition may be either an oil-in-water emulsified composition or a water-in-oil emulsified composition. When it is an oil-in-water emulsion composition, it is easy to adjust the viscosity, and when it is a water-in-oil emulsion composition, it is easy to formulate, and the uniform coating property is also improved.
The external preparation for skin of the present invention is preferably an emulsified composition from the viewpoint of excellent feeling in use, and is preferably a water-in-oil type emulsified composition from the viewpoint of excellent protective effect against ultraviolet rays, infrared rays, etc. and excellent feeling in use. preferable.
The external preparation for skin of the present invention may be a skin preparation for protecting against ultraviolet rays or infrared rays, or a skin cosmetic such as lotion, cream, milky lotion, serum, suntan, makeup base cosmetic, and the like.

<Component (A): Metal oxide>
The skin external preparation of the present invention contains, as component (A), one or more selected from the group consisting of spherical metal oxides (A1) and plate-like metal oxides (A2) having an average particle size of 350 nm or more and 2,500 nm or less. Contains metal oxides. By containing the component (A), the topical preparation for skin of the present invention has an excellent protective effect against ultraviolet rays, infrared rays, etc., provides a skin temperature rise suppressing effect and fatigue suppressing effect, and prevents whitening when applied to the skin. It has the effect of being able to suppress it.

(Component (A1): spherical metal oxide having an average particle size of 350 nm or more and 2,500 nm or less)
Component (A1) used in the present invention is a spherical metal oxide having an average particle size of 350 nm or more and 2,500 nm or less. The term "spherical" as used herein includes a spherical shape and a substantially spherical shape. In component (A1), the shape of either the primary particles or the secondary particles of the metal oxide may be spherical. When the component (A1) exists as secondary particles, the average particle size of the component (A1) means the average particle size of the secondary particles.
The average particle diameter of component (A1) is 350 nm or more, preferably 400 nm or more, more preferably 700 nm or more, and still more preferably 800 nm or more, from the viewpoint of protection against ultraviolet rays, infrared rays, and the like. In addition, from the viewpoint of the protective effect against ultraviolet rays, infrared rays, etc., and from the viewpoint of suppressing whitening when applied to the skin, it is 2,500 nm or less, preferably 2,000 nm or less, more preferably 1,800 nm or less. It is more preferably 1,500 nm or less, still more preferably 1,200 nm or less. The average particle diameter of component (A1) is 350 nm or more and 2,500 nm or less, preferably 400 nm or more and 2,000 nm or less, more preferably 700 nm or more and 2,000 nm or less, still more preferably 700 nm or more and 1,800 nm or less, More preferably 700 nm or more and 1,500 nm or less, still more preferably 800 nm or more and 1,200 nm or less.
The average particle diameter of component (A1) is the median diameter (d ₅₀ ), which can be determined, for example, by laser diffraction/light scattering particle size distribution measurement. In the measurement, a solvent in which the component (A1) is easily dispersed can be used as appropriate. For example, purified water is used for metal oxides that are not surface-treated, and metal oxides that are surface-treated with silicone or the like are used. Silicone oils (eg, methylpolysiloxane, cyclopentasiloxane, etc.) can be used.

(Component (A2): Plate-shaped metal oxide)
Component (A2) used in the present invention is a plate-like metal oxide. Component (A2) is plate-shaped and preferably has a thickness and an aspect ratio within the ranges described below. Here, when a coating film is formed on the skin surface using an external preparation for skin containing component (A2), the reflectance of light observed on the upper surface side of the skin is reduced to light with a wavelength in the infrared region due to the light interference effect. is higher for light in the visible region, and lower for light with wavelengths in the visible region. As a result, a higher infrared protection effect can be obtained, and whitening when applied to the skin can be easily suppressed.

The thickness of the component (A2) is preferably 30 nm or more, more preferably 50 nm or more, still more preferably 60 nm or more, still more preferably 75 nm or more, still more preferably 90 nm or more, and still more preferably 90 nm or more, from the viewpoint of improving the infrared protection effect. It is preferably 100 nm or more. In addition, from the viewpoint of improving the infrared protection effect and suppressing whitening when applied to the skin, the thickness of the component (A2) is preferably 360 nm or less, more preferably 330 nm or less, still more preferably 310 nm or less. It is more preferably 280 nm or less, still more preferably 270 nm or less, still more preferably 230 nm or less, still more preferably 200 nm or less, and even more preferably 180 nm or less. The thickness of component (A2) is preferably 30 nm or more and 360 nm or less, more preferably 50 nm or more and 330 nm or less, still more preferably 60 nm or more and 310 nm or less, still more preferably 75 nm or more and 280 nm or less, still more preferably 90 nm or more and 270 nm or less. 100 nm or more and 230 nm or less, still more preferably 100 nm or more and 200 nm or less, and still more preferably 100 nm or more and 180 nm or less.
In the present invention, the thickness of component (A2) means the length of the shortest axis in the plate-like metal oxide particles.
The thickness of component (A2) can be obtained from an image observed by a scanning electron microscope (SEM). Specifically, the component (A2) was observed with an SEM at an observation magnification of 10,000 times, the thickness of 50 particles in the observed image was measured, and the average thickness per number was calculated. It is obtained by calculating

In addition, the aspect ratio of the component (A2) is preferably 3 or more, more preferably 5 or more, still more preferably 10 or more, from the viewpoint of improving the infrared protection effect and suppressing whitening when applied to the skin. Still more preferably 30 or more, still more preferably 50 or more, still more preferably 55 or more, preferably 300 or less, more preferably 230 or less, still more preferably 200 or less, still more preferably 140 or less, and more More preferably 125 or less, still more preferably 120 or less. The aspect ratio of component (A2) is preferably 3 or more and 300 or less, more preferably 3 or more and 230 or less, still more preferably 10 or more and 230 or less, still more preferably 30 or more and 230 or less, still more preferably 50 or more and 200 Below, more preferably 55 or more and 140 or less, still more preferably 55 or more and 125 or less, and still more preferably 55 or more and 120 or less.
The aspect ratio of component (A2) was determined by SEM observation under the same conditions as above, and the length of the shortest axis (thickness) and the length of the longest axis (major axis) in 50 particles in the observed image. is measured to calculate the aspect ratio (major diameter/thickness) of each particle, and the average value is obtained. Specifically, the aspect ratio of component (A2) can be measured by the method described in Examples.

Component (A2) preferably has a thickness of 30 nm or more and 360 nm or less and an aspect ratio of 3 or more and 300 or less from the viewpoint of improving the infrared protection effect and suppressing whitening when applied to the skin. Preferably, the thickness is 50 nm or more and 330 nm or less, and the aspect ratio is 3 or more and 230 or less, more preferably the thickness is 60 nm or more and 310 nm or less, and the aspect ratio is 10 or more and 230 or less, and still more preferably the thickness 75 nm or more and 280 nm or less, and an aspect ratio of 30 or more and 230 nm or less, more preferably a thickness of 90 nm or more and 270 nm or less, and an aspect ratio of 50 or more and 200 or less, and still more preferably a thickness of 100 nm or more and 230 nm or less. and an aspect ratio of 55 to 140, more preferably a thickness of 100 nm to 200 nm, and an aspect ratio of 55 to 125, still more preferably a thickness of 100 nm to 180 nm, and an aspect ratio is 55 or more and 120 or less.

The external preparation for skin may contain either component (A1) or component (A2) as component (A), or may contain both component (A1) and component (A2). . When the component (A) contains both the component (A1) and the component (A2), the mass ratio is not particularly limited, from the viewpoint of improving the infrared protection effect and from the viewpoint of suppressing whitening when applied to the skin. Therefore, the mass ratio (A1)/(A2) is preferably 10/90 to 90/10, more preferably 20/80 to 80/20, still more preferably 30/70 to 70/30.
In addition, the external preparation for skin may contain two or more components (A1) as component (A), and may contain two or more components (A2).

Examples of metal oxides in components (A1) and (A2) include titanium oxide, zinc oxide, zirconium oxide, iron oxide, aluminum oxide, and cerium oxide.
Among these, one or more selected from the group consisting of titanium oxide and zinc oxide is preferred, and titanium oxide is more preferred, from the viewpoint of the protective effect against ultraviolet rays, infrared rays, etc., particularly from the viewpoint of improving the infrared protective effect.
The crystal structure of titanium oxide may be any of rutile type, anatase type and amorphous type, but the rutile type is preferable from the viewpoint of protection against ultraviolet rays, infrared rays and the like.

Component (A1) and component (A2) may be metal oxides that have not been surface-treated, and in order to enhance dispersibility in external skin preparations, surface treatment such as hydrophobic treatment is performed by a known method as necessary. It may be a metal oxide that has been used. The component (A1) and the component (A2) are distinguished from particles other than metal oxide whose surface is treated with a metal oxide.

Examples of surface treatment agents used for surface treatment of metal oxides include silicones; alkylalkoxysilanes; fluorine-containing compounds such as perfluoroalkyl phosphates and perfluoroalcohols; amino acids such as N-acylglutamic acid; Soap; fatty acids such as stearic acid; alkyl phosphates; Among these, at least one selected from the group consisting of silicones and alkylalkoxysilanes is preferred.
Silicone as a surface treatment agent is not particularly limited, and examples include methylpolysiloxane, dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane [hydrogen dimethicone], methylcyclopolysiloxane, octamethylcyclotetrasiloxane, decamethyl Cyclopentasiloxane, dodecamethylcyclohexasiloxane, octamethyltrisiloxane, tetradecamethylhexasiloxane, dimethylsiloxane-methyl (polyoxyethylene) siloxane-methyl (polyoxypropylene) siloxane copolymer, dimethylsiloxane-methyl (polyoxy Ethylene)siloxane copolymer, dimethylsiloxane/methyl (polyoxypropylene) siloxane copolymer, dimethylsiloxane/methylcetyloxysiloxane copolymer, dimethylsiloxane/methylstearoxysiloxane copolymer, (alkyl acrylate/dimethicone) Various silicone oils such as copolymers (ASC) can be mentioned.
As the alkylalkoxysilane as the surface treatment agent, those having a branched or linear alkyl group of 6 to 20 carbon atoms are preferred, and octyltriethoxysilane and octyltrimethoxysilane are particularly exemplified.

From the viewpoint of enhancing the dispersibility of the component (A) in the external preparation for skin and further improving the protective effect against ultraviolet rays, infrared rays, etc., methylpolysiloxane, dimethylpolysiloxane, At least one selected from the group consisting of siloxane, methylhydrogenpolysiloxane, (alkyl acrylate/dimethicone) copolymer, and octyltriethoxysilane is preferred.
When component (A1) or component (A2) is a surface-treated metal oxide, the amount of coating with the surface treatment agent is adjusted from the viewpoint of increasing the dispersibility in the skin preparation for external use. ), preferably 1% by mass or more and 9% by mass or less, more preferably 2% by mass or more and 8% by mass or less.

Component (A) preferably contains component (A2) from the viewpoint of improving the infrared protection effect and suppressing whitening when applied to the skin.
Here, when the metal oxide constituting the component (A2) is a material with a high refractive index, a higher optical interference effect can be obtained. Therefore, component (A) more preferably contains at least one selected from the group consisting of plate-like titanium oxide and plate-like zinc oxide as component (A2), and more preferably contains plate-like titanium oxide.
When the component (A) contains the component (A2), the content of the component (A2) in the component (A) is, from the viewpoint of improving the infrared protection effect and suppressing whitening when applied to the skin, It is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, still more preferably 80% by mass or more, still more preferably 90% by mass or more and 100% by mass or less.

The content of component (A) in the external preparation for skin is 2% by mass or more, preferably 3% by mass or more, more preferably 5% by mass or more, from the viewpoint of improving the protective effect against ultraviolet rays, infrared rays, and the like. In addition, from the viewpoint of suppression of whitening when applied to the skin, the content is 50% by mass or less.
In addition, from the viewpoint of improving the infrared protection effect and suppressing whitening when applied to the skin, the content of component (A) in the external preparation for skin is more preferably within the following range.
When the component (A) is spherical titanium oxide having an average particle diameter of 350 nm or more and less than 800 nm, the content of the spherical titanium oxide in the external preparation for skin is more preferably 5% by mass or more and 30% by mass or less, still more preferably It is 5 mass % or more and 25 mass % or less.
When the component (A) is spherical titanium oxide having an average particle diameter of 800 nm or more and 2,500 nm or less, the content of the spherical titanium oxide in the external preparation for skin is more preferably 5% by mass or more and 40% by mass or less. It is preferably 5% by mass or more and 30% by mass or less.
When the component (A) is plate-like titanium oxide, the content of the plate-like titanium oxide in the external preparation for skin is more preferably 5% by mass or more and 30% by mass or less.
When component (A) is spherical zinc oxide or plate-like zinc oxide having an average particle size of 350 nm or more and 2,500 nm or less, the content of said spherical zinc oxide or plate-like zinc oxide in the external preparation for skin is more preferably 7 mass % or more and 50 mass % or less, more preferably 10 mass % or more and 50 mass % or less.

In addition, the content of component (A) in the non-volatile components of the external preparation for skin is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 5% by mass or more, from the viewpoint of improving the protective effect against ultraviolet rays, infrared rays, and the like. It is 10% by mass or more. From the viewpoint of suppressing whitening when applied to the skin, the content is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and even more preferably 20% by mass or less. The content of component (A) in the non-volatile components of the external preparation for skin is preferably 3% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 40% by mass or less, and still more preferably 10% by mass or more. It is 30% by mass or less, more preferably 10% by mass or more and 20% by mass or less.
The term "non-volatile component in the external skin preparation" as used herein means a component obtained by excluding water, an aqueous medium described later, and a volatile oil (an oil other than component (B)) from the total amount of the external skin preparation.

The viscosity (mPa s) of the topical skin preparation relative to the content (% by mass) of component (A) in the topical skin preparation is adjusted according to the content of component (A) to improve uniform applicability. , From the viewpoint of uniformly disposing the component (A) on the skin surface, the [viscosity of the external preparation for skin (mPa s) / content of component (A) in the external preparation for skin (% by mass)] is preferably 100. above, more preferably 250 or more, still more preferably 300 or more, still more preferably 350 or more, preferably 25,000 or less, more preferably 20,000 or less, still more preferably 15,000 or less, still more It is preferably 10,000 or less, more preferably 5,000 or less, and even more preferably 3,000 or less. The [viscosity of the external skin preparation (mPa·s)/content of component (A) in the external skin preparation (% by mass)] is preferably 100 or more and 25,000 or less, more preferably 250 or more and 20,000. 300 or more and 15,000 or less, still more preferably 350 or more and 10,000 or less, still more preferably 350 or more and 5,000 or less, still more preferably 350 or more and 3,000 or less.

A commercially available metal oxide can also be used as component (A).
For example, commercially available spherical titanium oxide used as the component (A1) includes "ST-750EC" manufactured by Titan Kogyo Co., Ltd., "R-38L" manufactured by Sakai Chemical Industry Co., Ltd., and the like. Zinc includes "LP-ZINC-2KS" manufactured by Sakai Chemical Industry Co., Ltd., and the like.
Commercially available plate-like titanium oxide used as component (A2) includes "Featheleve PT-9001K", "Featheleve PT-7001K", "Featheleve PT-7401K", "Featheleve PT-7801K" and "Featheleve PT" manufactured by CQV. -7901K", surface-coated products thereof, and the like, and commercially available plate-like zinc oxide includes "XZ-1000F-LP" manufactured by Sakai Chemical Industry Co., Ltd., and the like.

<Component (B): non-volatile oil>
The external preparation for skin of the present invention contains a non-volatile oil as component (B) from the viewpoints of easily adjusting the viscosity to a desired level and improving the protective effect against ultraviolet rays, infrared rays, etc. by improving uniform application properties. A non-volatile oil refers to an oil having an evaporation rate of less than 20% at 25° C. for 6 hours, as measured by the following method (1).
Method (1): Place a filter paper with a diameter of 90 mm in a glass petri dish with a diameter of 120 mm. After 6 hours, the residue of the sample is measured and the amount of evaporation is calculated.

In addition, component (B) is preferably liquid at 25° C. under 1 atm. More specifically, component (B) has a viscosity at 25° C. of preferably 500 mPa·s or less, more preferably 300 mPa·s or less, even more preferably 100 mPa·s or less, and still more preferably It is 50 mPa·s or less, preferably 5 mPa·s or more.
The viscosity was measured using a Brookfield viscometer "TVB-10" (manufactured by Toki Sangyo Co., Ltd.). 1. It can be measured under the conditions of 25° C., 60 rpm, and 1 minute.

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

Examples of non-volatile liquid ester oils include monoesters of fatty acids having 8 to 18 carbon atoms and branched alcohols having 2 to 22 carbon atoms, and triesters of branched fatty acids having 6 to 18 carbon atoms and glycerin. , a diester of a dicarboxylic acid having 2 to 18 carbon atoms and a branched alcohol having 2 to 18 carbon atoms, a diester of a fatty acid having 6 to 18 carbon atoms and a dialcohol having 2 to 10 carbon atoms, and an alkyl benzoate One or more selected from the group consisting of
Monoesters of fatty acids having 8 to 18 carbon atoms and branched alcohols having 2 to 22 carbon atoms include isononyl isononanoate, isotridecyl isononanoate, isopropyl myristate, isocetyl myristate, octyldodecyl myristate, isopropyl palmitate, Examples include ethylhexyl palmitate and 2-hexyldecyl palmitate.
Examples of triesters of fatty acids having 6 to 18 carbon atoms and glycerin include glyceryl tri-2-ethylhexanoate and glyceryl tri(caprylate/caprate).
Examples of diesters of dicarboxylic acids having 2 to 18 carbon atoms and branched alcohols having 2 to 18 carbon atoms include di-2-ethylhexyl sebacate, diisopropyl sebacate and diisostearyl malate.
Examples of diesters of fatty acids having 6 to 18 carbon atoms and dialcohols having 2 to 10 carbon atoms include diethylene glycol dicaprate, neopentyl glycol dicaprate, and neopentyl glycol di-2-ethylhexanoate.
Examples of the alkyl benzoate include alkyl benzoate (C12 to C15) (eg Finsolv TN; manufactured by Innospec Active Chemicals LLC).

Among the ester oils used as component (B), from the viewpoint of ease of viscosity adjustment, the viewpoint of improving the solubility of thickeners and the like described later, and the viewpoint of suppressing stickiness when applied to the skin, C 12 Monoesters of fatty acids having 18 or more and branched alcohols having 2 to 22 carbon atoms, triesters of branched fatty acids having 6 to 18 carbon atoms and glycerin, dicarboxylic acids having 2 to 18 carbon atoms and 2 or more carbon atoms One or more selected from the group consisting of diesters with branched alcohols of 18 or less, diesters of fatty acids with 6 to 18 carbon atoms and branched dialcohols with 2 to 10 carbon atoms, and alkyl benzoates (C12 to C15) isopropyl myristate, isocetyl myristate, octyldodecyl myristate, isopropyl palmitate, ethylhexyl palmitate, 2-hexyldecyl palmitate, glyceryl tri-2-ethylhexanoate, diisopropyl sebacate, di-2-ethylhexyl sebacate, One or more selected from the group consisting of diisostearyl malate, neopentyl glycol di-2-ethylhexanoate, neopentyl glycol dicaprate, and alkyl benzoate (C12-C15) is more preferred, and isopropyl palmitate is even more preferred. .

As the nonvolatile liquid silicone oil, methylpolysiloxane is preferable, and methylpolysiloxane having a viscosity of 20 mPa·s or less at 25°C is more preferable.

Non-volatile liquid hydrocarbon oils include liquid paraffin, light liquid isoparaffins such as hydrogenated polyisobutene, heavy liquid isoparaffins, liquid ozokerite, squalane, pristane, squalene, and isohexadecane.

Non-volatile liquid higher fatty acids include fatty acids having 12 to 22 carbon atoms, and specific examples include oleic acid, isostearic acid, linoleic acid, and linolenic acid.
Nonvolatile liquid higher alcohols include, for example, alcohols having 12 to 28 carbon atoms, and specific examples include oleyl alcohol, 2-decyltetradecinol, dodecanol, isostearyl alcohol, octyldodecanol, and the like. mentioned.

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

The content of the component (B) in the external preparation for skin of the present invention is preferably 1% by mass or more from the viewpoint of easy adjustment to a desired viscosity and enhancement of the protective effect against ultraviolet rays, infrared rays, etc. by enhancing uniform application properties. , more preferably 5% by mass or more. In addition, from the viewpoint of suppressing stickiness when applied to the skin, it is preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less, and even more preferably 65% by mass or less.
When the external preparation for skin of the present invention is a water-in-oil emulsified composition, the content of component (B) in the external preparation for skin is more preferably 15% by mass or more from the viewpoint of water-in-oil type. , Still more preferably 20% by mass or more, still more preferably 25% by mass or more, still more preferably 30% by mass or more, and even more preferably 35% by mass or more.
When the external preparation for skin of the present invention is an oil-in-water emulsified composition, the content of component (B) in the external preparation for skin is more preferably 30% by mass or less from the viewpoint of making it oil-in-water. More preferably 20 mass % or less, still more preferably 10 mass % or less.

In the external preparation for skin of the present invention, the mass ratio of the content of component (B) to the content of component (A) [(B)/(A)] increases the uniformity of application, thereby protecting against ultraviolet rays, infrared rays, etc. From the viewpoint of enhancing the effect and improving the feeling of use, it is preferably 0.05 or more, more preferably 0.1 or more, still more preferably 0.2 or more, even more preferably 0.5 or more, and even more preferably 1 above, more preferably 2 or more, still more preferably 3 or more, still more preferably 3.6 or more, and from the viewpoint of suppressing stickiness when applied to the skin, preferably 60 or less, more preferably 50 or less, More preferably 30 or less, still more preferably 20 or less, still more preferably 10 or less, and even more preferably 8 or less. The mass ratio [(B)/(A)] is preferably 0.05 or more and 60 or less, more preferably 0.1 or more and 50 or less, still more preferably 0.2 or more and 30 or less, and even more preferably 0.2 or more. 5 or more and 20 or less, more preferably 1 or more and 10 or less, still more preferably 2 or more and 10 or less, still more preferably 3 or more and 10 or less, and even more preferably 3.6 or more and 8 or less.

In addition, from the viewpoint of the protective effect against ultraviolet rays, infrared rays, etc., and from the viewpoint of suppressing whitening when applied to the skin, the total content of the component (A) and the component (B) in the external preparation for skin is preferably 2. % by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, even more preferably 30% by mass or more, even more preferably 40% by mass or more, still more preferably 45% by mass or more, and even more preferably is 47% by mass or more, more preferably 50% by mass or more, and 100% by mass or less.

<Thickener>
The external preparation for skin of the present invention preferably further contains a thickening agent from the viewpoints of facilitating viscosity adjustment, improving uniform applicability, and enhancing the protective effect against ultraviolet rays, infrared rays, and the like. In the present invention, the "thickener" means an additive that acts to thicken the external preparation for skin.
Examples of thickeners include oil thickeners, water-soluble thickeners, and the like, which can be appropriately selected according to the dosage form of the external preparation for skin. For example, when the external preparation for skin is a water-in-oil emulsified composition, an oil thickener (oil gelling agent) is preferable from the viewpoint of easy thickening without changing the formulation.
Examples of oil thickeners include those used in ordinary external skin preparations, such as solid waxes, organically modified clay minerals, fumed silica, colloidal silica, dextrin fatty acid esters, metallic soaps, sucrose fatty acid esters, amino acids. system gelling agents and the like. Among these, solid waxes, organically modified clay minerals, dextrin fatty acid esters, and amino acid-based waxes are preferred from the viewpoints of facilitating viscosity adjustment, improving uniform coating properties, and enhancing the protective effect against ultraviolet rays, infrared rays, and the like. It is one or more selected from the group consisting of gelling agents, and more preferably one or more selected from the group consisting of solid waxes, organically modified clay minerals, and dextrin fatty acid esters.

Solid waxes include waxes having a melting point of 61° C. or higher. Waxes with a melting point of 61°C or higher exhibit solid properties at 25°C.
In the present invention, the melting point is measured according to the Standards for Quasi-drug Ingredients, Method 1, Method 2, or Method 3 of general test methods. As for which method to use, if there is a measurement method described in the standards for quasi-drug raw materials for each component, follow that method. If there is no description, select the measurement method in consideration of the melting point. Specifically, Method 1 is used when the melting point is much higher than 80°C, Method 2 is used for solid fats with a lower melting point, and Method 3 is used for what is called paste oil in catalogs. However, any method may be used as long as it can be measured.

Waxes having a melting point of 61° C. or higher are not particularly limited as long as they are used in ordinary external skin preparations. Examples include mineral waxes such as ozokerite and ceresin; petroleum waxes such as paraffin and microcrystalline wax; Synthetic hydrocarbons such as tropsch wax, polyethylene wax, synthetic hydrocarbon wax; vegetable waxes such as carnauba wax, candelilla wax, rice wax, sunflower wax; animal waxes such as beeswax and whale wax; silicone wax, synthetic beeswax, etc. synthetic wax; and the like.
Among these, one or more selected from the group consisting of petroleum waxes and silicone waxes is preferable from the viewpoint of facilitating viscosity adjustment, improving uniform coating properties, and improving the protective effect against ultraviolet rays, infrared rays, and the like.
These waxes preferably have a melting point of 65° C. or higher and 140° C. or lower, 70° C. or higher, and 70° C. or higher, from the viewpoints of facilitating viscosity adjustment, improving uniform coating properties, and enhancing the protective effect against ultraviolet rays, infrared rays, and the like. 110° C. or less is more preferable.

The organically modified clay mineral is not particularly limited as long as it is used in usual external preparations for skin. Cation-modified clay minerals obtained by treatment with salt-type cationic surfactants can be mentioned.
Specifically, one or more selected from the group consisting of benzyldimethylstearylammonium chloride and dimethyldistearylammonium chloride is preferable, and dimethyldistearylammonium chloride is more preferable.
Commercially available organic modified clay minerals include "Bentone 38", "Bentone 38VCG" and "Bentone 27" manufactured by Elementis Japan.

The organically modified clay mineral can also be used as a premixed gel diluted with a solvent from the viewpoint of improving workability and thickening effect.
Specifically, a premixed gel in which an organically modified clay mineral is previously dispersed in a solvent is preferred. The solvent is not limited as long as it can be gelled by an organically modified clay mineral, and octyldodecanol, mineral oil, and the like are preferable from the viewpoint of improving the thickening effect. Moreover, from the viewpoint of efficiently dispersing the organically modified clay mineral, it is preferable to further contain a polar additive such as propylene carbonate, ethanol, water, and various surfactants.
The content of the organically modified clay mineral in the premix gel is preferably 5% by mass or more, more preferably 8% by mass, from the viewpoint of improving workability and thickening effect, and suppressing oil separation of the premix gel itself. % by mass or more, more preferably 10% by mass or more, preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 18% by mass or less.
Commercially available premixed gels include "Bentongel EUGV", "Bentongel MIOV", "Bentongel VS-5 PCV", "Bentongel PTM V", and "Bentongel GTCC V" manufactured by Elementis Japan.

The dextrin fatty acid ester is not particularly limited as long as it is used in ordinary skin preparations for external use. An ester of a fatty acid having 8 to 24 carbon atoms and dextrin is preferable, and an ester of a fatty acid having 14 to 20 carbon atoms and dextrin is more preferable. In addition, the dextrin preferably has an average degree of polymerization of 3 or more and 150 or less.
Specific examples include dextrin palmitate, dextrin stearate, dextrin palmitate/stearate, dextrin oleate, dextrin isopalmitate, dextrin isostearate, dextrin myristate, dextrin palmitate/2-ethylhexanoate, and the like. .
Among these, dextrin palmitate, dextrin myristate, and dextrin palmitate/2-ethylhexanoate are used from the viewpoints of facilitating viscosity adjustment, improving uniform coating properties, and enhancing the protective effect against ultraviolet rays, infrared rays, and the like. Preferred are those containing at least dextrin palmitate.
Commercially available dextrin fatty acid esters include dextrin palmitate manufactured by Chiba Flour Mills Co., Ltd. (“Leopal KL2”, “Leopal KS2”, “Leopal TL2”), dextrin palmitate/2-ethylhexanoate “Leopal TT2”, Dextrin myristate "Rheopearl MKL2" and the like can be mentioned.

As the amino acid-based gelling agent, any amino acid-based gelling agent can be used without particular limitation as long as it is used in usual external preparations for skin. Specifically, dibutyl lauroyl glutamide and dibutylethylhexanoyl glutamide are preferred.
Commercially available amino acid-based gelling agents include dibutyl lauroyl glutamide "GP-1" and dibutyl ethylhexanoyl glutamide "EB-21" manufactured by Ajinomoto Co., Inc., and the like.

The amino acid-based gelling agent can also be used as a premixed gel diluted and dissolved with a solvent from the viewpoint of improving workability and thickening effect.
Specifically, a premixed gel obtained by previously dissolving an amino acid-based gelling agent in a solvent is preferred. The solvent is not limited as long as it can be gelled by an amino acid-based gelling agent, but octyldodecanol, isostearic acid, and the like are preferable from the viewpoint of improving the thickening effect.
The content of the amino acid-based gelling agent in the premix gel is preferably 10% by mass or more, more preferably 10% by mass or more, from the viewpoint of improving workability and thickening effect, and suppressing oil separation of the premix gel itself. It is 15% by mass or more, more preferably 20% by mass or more, preferably 45% by mass or less, more preferably 40% by mass or less, and even more preferably 36% by mass or less.
Commercially available premix gels include "AJK-OD2046" (containing 20% by mass of an amino acid-based gelling agent) and "AJK-IS3613" (containing 36% by mass of an amino acid-based gelling agent) manufactured by Kokyu Alcohol Kogyo Co., Ltd. etc.

One or two or more thickeners can be used. When the external preparation for skin contains a thickening agent, the content of the thickening agent in the external preparation for skin is adjusted from the viewpoint of adjusting the viscosity, improving the uniform application property, and improving the protective effect against ultraviolet rays, infrared rays, etc. Preferably 0.5% by mass or more, more preferably 1% by mass or more, still more preferably 2% by mass or more, still more preferably 3% by mass or more, and preferably 50% by mass or less, more preferably 30% by mass % or less, more preferably 25 mass % or less, still more preferably 20 mass % or less, still more preferably 15 mass % or less. The content of the thickening agent in the external preparation for skin is preferably 0.5% by mass or more and 50% by mass or less, more preferably 0.5% by mass or more and 30% by mass or less, and still more preferably 1% by mass or more and 25% by mass. % by mass or less, more preferably 2% by mass or more and 20% by mass or less, and even more preferably 3% by mass or more and 15% by mass or less.

<Emulsifier>
The external preparation for skin of the present invention may further contain an emulsifier from the viewpoint of enhancing the dispersibility of component (A) and from the viewpoint of preparing an emulsified composition. In the present invention, the "emulsifier" means an additive other than the thickener, which has emulsifying properties.
The emulsifier used in the present invention may be either a low-molecular-weight emulsifier or a high-molecular-weight emulsifier, but a high-molecular-weight emulsifier is preferable from the viewpoint of enhancing the dispersibility of component (A) and facilitating viscosity adjustment.
As the polymer emulsifier, a polymer emulsifier having a hydrophilic site and a hydrophobic site is preferable, and examples thereof include alkyl-modified polyacrylic acid-based polymer, alkyl-modified polysaccharide-based polymer, and oxazoline-modified silicone.

Examples of alkyl-modified polyacrylic acid-based polymers include (meth)acrylic acid/alkyl (meth)acrylate copolymers, alkyl acrylate/alkyl methacrylate/polyoxyethylene stearyl ether methacrylate copolymers, and the like. .

Examples of alkyl-modified polysaccharide polymers include hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, methylcellulose, sodium carboxymethylcellulose, stearoxyhydroxypropylmethylcellulose, laureth-13PG hydroxyethylcellulose, stearoxy PG hydroxyethylcellulose sulfonate, and the like. be done.

Examples of the oxazoline-modified silicone include polymers having a hydrophilic segment having N-acylalkyleneimine as a repeating unit and an organopolysiloxane segment as structural units. For example, N-propionylpolyethyleneimine/methylpolysiloxane copolymer ( POLYSILICONE-9) can be exemplified.

One or two or more emulsifiers can be used. Among the above, oxazoline-modified silicone is preferable from the viewpoint of enhancing the dispersibility of component (A) and the viewpoint of ease of viscosity adjustment.

When the topical skin preparation of the present invention contains an emulsifier, the content of the emulsifier in the topical skin preparation is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, from the viewpoint of emulsifying performance. Also, it is preferably 15% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, even more preferably 3% by mass or less, and even more preferably 1% by mass or less. The content of the emulsifier in the external preparation for skin is preferably 0.1% by mass or more and 15% by mass or less, more preferably 0.1% by mass or more and 10% by mass or less, and still more preferably 0.1% by mass or more and 5 % by mass or less, more preferably 0.1% by mass or more and 3% by mass or less, and even more preferably 0.2% by mass or more and 1% by mass or less.

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

As the dispersant used in the present invention, a nonionic surfactant is preferable from the viewpoint of enhancing the dispersibility of the component (A). The nonionic surfactant is not particularly limited as long as it is used in usual external preparations for skin, and silicone surfactants, fluorine-containing surfactants and the like can also be used.
Examples of nonionic surfactants used as dispersants include alkanolamides, amine oxides, polyoxyethylene alkyl ethers, polyoxyethylene hydrogenated castor oils, polyoxyethylene fatty acid amides, polyoxyethylene alkylamines, alkyl saccharides, α -monoalkyl glyceryl ether, polyether-modified silicone, etc., and one or more of these can be used.

From the viewpoint of further enhancing the dispersibility of component (A), the dispersant preferably contains a nonionic silicone-based surfactant, and more preferably contains a polyether-modified silicone.
Examples of commercially available polyether-modified silicones used as dispersants include "KF-6012" (poly(oxyethylene/oxypropylene) methylpolysiloxane copolymer) manufactured by Shin-Etsu Chemical Co., Ltd., Shin-Etsu Chemical Co., Ltd. Co., Ltd. "KF-6015", "KF-6017", "KF-6028", "KF-6038", Dow Toray Co., Ltd. "SH3775M" (above, polyoxyethylene methyl polysiloxane copolymer), "SH3772C" manufactured by Dow Toray Industries, Inc., and the like.

As a nonionic surfactant other than the above used as a dispersant, a polyoxyethylene alkyl ether type nonionic surfactant is more preferable. Commercially available polyoxyethylene alkyl ether type nonionic surfactants include, for example, "EMULGEN 121-G" (polyoxyethylene (21) lauryl ether) manufactured by Kao Corporation, and "EMULGEN 1620G" manufactured by Kao Corporation. (polyoxyethylene (20) 2-hexyldecyl ether), Kao Corporation "EMULGEN 2020G" (polyoxyethylene (20) octyldodecyl ether), and the like.

One or two or more dispersants can be used. When the external preparation for skin of the present invention contains a dispersant, the content of the dispersant in the external preparation for skin is preferably 0.1% by mass or more, more preferably 0.1% by mass or more, from the viewpoint of enhancing the dispersibility of component (A). It is 0.3% by mass or more, more preferably 0.5% by mass or more, and preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. The content of the dispersant in the external preparation for skin is preferably 0.1% by mass or more and 15% by mass or less, more preferably 0.3% by mass or more and 10% by mass or less, and still more preferably 0.5% by mass or more. It is 5% by mass or less.

<Water>
The external preparation for skin of the present invention preferably further contains water from the viewpoint of giving a refreshing feel to the skin.
When the topical skin preparation contains water, the content of water in the topical skin preparation can be appropriately selected depending on the dosage form. % by mass or more, more preferably 10% by mass or more, preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less.

<Aqueous medium>
The external preparation for skin of the present invention may further contain an aqueous medium other than water from the viewpoint of dispersing the component (A) and dispersing or dissolving other ingredients to further improve uniform application properties. Examples of the aqueous medium include monohydric alcohols having 4 or less carbon atoms such as ethanol, isopropyl alcohol, and butyl alcohol; Low-molecular-weight diols and triols of 6 or less are included. Among these, one or more selected from the group consisting of monohydric alcohols having 4 or less carbon atoms are preferable, and ethanol is more preferable.

When the topical skin preparation contains an aqueous medium, the content of the aqueous medium in the topical skin preparation can be appropriately selected depending on the dosage form. From the viewpoint of further improving uniform coating properties by increasing the is 20% by mass or less, more preferably 10% by mass or less. The content of the aqueous medium in the external preparation for skin is preferably 0.1% by mass or more and 50% by mass or less, more preferably 0.1% by mass or more and 30% by mass or less, and still more preferably 0.1% by mass or more. 20 mass % or less, more preferably 0.5 mass % or more and 10 mass % or less.

In addition, the total content of water and aqueous medium in the skin external preparation is preferably 2% by mass or more, more preferably 5% by mass or more, and still more preferably 10% by mass, from the viewpoint of further improving the refreshing feeling of use. above, preferably 70% by mass or less, more preferably 60% by mass or less, even more preferably 40% by mass or less, and even more preferably 35% by mass or less.

<Other ingredients>
The external preparation for skin of the present invention may contain other ingredients, such as ultraviolet absorbers, ultraviolet scattering agents, volatile oils, antiperspirants, fragrances, moisturizers, bactericides, and pH adjusters, if necessary, in addition to the above ingredients. , antioxidants, preservatives and the like can also be contained.

(Ultraviolet absorber)
The external preparation for skin of the present invention may further contain an ultraviolet absorber from the viewpoint of improving the ultraviolet protection effect.
The UV absorber is preferably an organic UV absorber other than the component (B), and an oil-soluble organic UV absorber or a water-soluble organic UV absorber can be used. From the viewpoint of improving the UV protection effect, suppressing whitening when applied to the skin, and suppressing stickiness, the UV absorber is preferably an oil-soluble organic UV absorber. In the present invention, "oil-soluble" means water-insoluble, and specifically, it means that the solubility in water at 25°C is 1 w/w% or less.
From the viewpoint of obtaining the effects of the present invention, it is preferable that the UV absorber does not contain an inorganic UV absorber such as a UV absorber obtained by coating the surface of an inorganic filler with a UV 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;
2-Ethylhexyl paramethoxycinnamate (for example, "Ubinal MC80" manufactured by BASF), glyceryl mono-2-ethylhexanoate di-paramethoxycinnamate, methyl 2,5-diisopropylcinnamate, methylbis trimethoxycinnamate (Trimethylsiloxy)silyl isopentyl, cinnamic acid-based UV absorbers such as a mixture of isopropyl para-methoxycinnamate and diisopropyl cinnamate;
Benzoylmethane-based UV absorbers such as 4-isopropyldibenzoylmethane, 4-tert-butyl-4′-methoxydibenzoylmethane (for example, “Parsol 1789” manufactured by DSM Nutrition Japan);
Octocrylene (e.g., DSM Nutrition Japan Co., Ltd. "PARASOL 340"), dimethoxybenzylidene dioxoimidazolidine 2-ethylhexylpropionate (e.g., Ajinomoto Co., Ltd. "Soft Shade DH"), 1-(3,4-dimethoxyphenyl) )-4,4-dimethyl-1,3-pentanedione, cinoxate, methyl-O-aminobenzoate, 3-(4-methylbenzylidene)camphor, octyltriazone, diethylaminohydroxybenzoyl hexylbenzoate (2-(4- diethylamino-2-hydroxybenzoyl)benzoic acid hexyl ester, such as "Ubinal Aplus" manufactured by BASF), bisethylhexyloxyphenol methoxyphenyltriazine (2,4-bis{[4-(2-ethylhexyloxy)-2-hydroxy] Phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine, such as "Tinosorb S" manufactured by BASF), methylenebisbenzotriazolyltetramethylbutylphenol (eg, "Tinosorb M" manufactured by BASF), 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine (hereinafter also referred to as "ethylhexyltriazone"; for example, "Ubinal T150" manufactured by BASF); mentioned.

As the water-soluble organic UV absorber, a salicylic acid UV absorber, a cinnamic acid UV absorber, a benzoylmethane UV absorber, and other organic UV absorbers having a solubility in water of 1 w/w% are selected. More than one can be used, and examples thereof include salicylic acid triethanolamine salt, p-methoxyhydrocinnamic acid diethanolamine salt, and the like.

Among the above, from the viewpoint of improving the UV protection effect, the UV absorber includes 2-ethylhexyl paramethoxycinnamate, 4-tert-butyl-4′-methoxydibenzoylmethane, octocrylene, dimethoxybenzylidene dioxoimidazolidine propionic acid. 2-ethylhexyl, diethylaminohydroxybenzoylhexylbenzoate, bisethylhexyloxyphenol methoxyphenyltriazine, methylenebisbenzotriazolyltetramethylbutylphenol, and 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]- One or more selected from the group consisting of 1,3,5-triazines are preferable, and 2-ethylhexyl paramethoxycinnamate, hexyl diethylaminohydroxybenzoylbenzoate, bisethylhexyloxyphenol methoxyphenyltriazine, and 2,4,6- More preferably one or more selected from the group consisting of tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine, and two or more of these from the viewpoint of protecting against both UVA and UVB. A combination is more preferable. More preferably, it is one or more selected from the group consisting of 2-ethylhexyl paramethoxycinnamate, hexyl diethylaminohydroxybenzoylbenzoate, and bisethylhexyloxyphenol methoxyphenyltriazine, and a combination of two or more thereof is more preferable. More preferred.

When the external preparation for skin of the present invention contains an ultraviolet absorber, the content thereof is preferably 0.2% by mass or more, more preferably 1.5% by weight, in the external preparation for skin from the viewpoint of improving the ultraviolet protection effect. Above, more preferably 5% by mass or more, still more preferably 7% by mass or more. From the viewpoint of improving the feeling of use of the external preparation for skin, 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 the ultraviolet absorber in the external preparation for skin is preferably 0.2% by mass or more and 30% by mass or less, more preferably 1.5% by mass or more and 25% by mass or less, and even more preferably. is 5% by mass or more and 20% by mass or less, and more preferably 7% by mass or more and 15% by mass or less.

(Ultraviolet scattering agent)
The external preparation for skin of the present invention may further contain an ultraviolet scattering agent from the viewpoint of improving the ultraviolet protection effect.
As the ultraviolet scattering agent, inorganic particles are preferable because they are highly effective in scattering ultraviolet rays. ) and metal oxide particles other than the plate-shaped metal oxide (A2) are more preferable. Examples of the metal oxide include titanium oxide, zinc oxide, iron oxide, zirconium oxide, and aluminum oxide other than component (A), and are selected from the group consisting of titanium oxide and zinc oxide other than component (A). Species or more are more preferred.

From the viewpoint of enhancing the dispersibility in external skin preparations, the inorganic particles used in the UV scattering agent are preferably hydrophobized by surface treatment. Examples of surface treatment methods for hydrophobization include silicone treatment with methylhydrogenpolysiloxane (hydrogendimethicone), methylpolysiloxane (dimethicone), methylhydrogenpolysiloxane/dimethylpolysiloxane copolymer, etc.; perfluoroalkyl Fluorine treatment with phosphate ester, perfluoroalcohol, etc.; amino acid treatment with N-acylglutamic acid, etc.; hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, octadecyltrimethoxysilane, octyltriethoxysilane, trifluoropropyltri Silane compound treatment with methoxysilane, heptadecafluorodecyltrimethoxysilane, etc.; silazane treatment with hexamethyldisilazane, octyldisilazane, etc.; lecithin treatment; metal soap treatment; caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid , fatty acid treatment with 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.; mentioned. One or more of these surface treatment methods can be used.

The particle shape of the UV-scattering agent may be spherical with an average particle size of less than 350 nm, rod-like, spindle-like, needle-like, or amorphous, but is not particularly limited as long as it has an UV-scattering effect.
The average particle size of the UV scattering agent is usually 1 nm or more, preferably 5 nm or more, more preferably 8 nm or more, and still more preferably 10 nm or more from the viewpoint of improving the UV protection effect. In addition, from the viewpoint of suppressing whitening when applied to the skin, it is preferably less than 350 nm, more preferably 300 nm or less, even more preferably 100 nm or less, and even more preferably 60 nm or less.
The average particle size can be measured by the same method as for the average particle size of component (A1).

Commercially available UV scattering agents can also be used. Examples of commercially available titanium oxide particles used as UV scattering agents include "MT-100TV" (aluminum hydroxide, stearic acid treatment) and "MTY-110M3S" (aluminum hydroxide, silica, hydro Gendimethicone treatment) and the like.

Examples of commercially available zinc oxide particles used as UV scattering agents include "FINEX-50-LPTM" (dimethicone treatment), "FINEX-25" (no surface treatment), "FINEX- 25LP" (dimethicone treatment), "MZ-300" manufactured by Tayca Corporation (no surface treatment), "MZ-504R3M" (hydrogen dimethicone treatment), "MZY-303S" (hydrodimethicone treatment), "MZ-306X" "(triethoxysilylethylpolydimethylsiloxyethylhexyl 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” and the like.

The ultraviolet scattering agent can be used alone or in combination of two or more.
When the external preparation for skin of the present invention contains an ultraviolet scattering agent, the content thereof is preferably 1% by mass or more, more preferably 3% by mass or more, and still more preferably 5% by mass or more, from the viewpoint of improving the ultraviolet protection effect. is. In addition, from the viewpoint of suppressing whitening when applied to the 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.

<Application>
The external skin preparation of the present invention can be used as a skin external preparation for protecting against ultraviolet rays or infrared rays, for suppressing skin temperature rise, or for suppressing fatigue.
By applying the external preparation for skin of the present invention to the skin, it is possible to effectively protect the skin even when the skin is irradiated with ultraviolet light, infrared light, or light containing wavelengths in the ultraviolet to infrared region such as sunlight. As a result, it is possible to suppress the photoaging of the skin and the increase in skin temperature caused by the irradiation of ultraviolet rays, infrared rays, sunlight, etc., and also to obtain the heat shielding effect of the skin.
In addition, when an animal such as a human performs endurance exercise in a sunlight irradiation environment, fatigue is likely to occur if the amount of sunlight irradiation is large. It is possible to suppress fatigue caused by

The anti-fatigue effect of using an external preparation for skin can be evaluated, for example, by the following method.
The external preparation for skin is applied to the exposed areas (face, chest, back, arms, backs of hands, feet) of the test subject at a concentration of 2 mg/cm ² and allowed to dry for 15 minutes. Next, artificial solar light sources are placed in front, back, left and right of the subject, and while irradiating simulated sunlight toward the upper body of the subject, an ergometer (for example, "Standard Ergometer 828E" manufactured by Monarch) is used to maintain a constant heart rate. Continue the exercise for 30 minutes while maintaining the number. Subjects self-evaluate heat sensation and fatigue sensation during exercise to evaluate the effect of topical skin preparations on exercise performance.

<Method for producing external preparation for skin>
The method for producing the external preparation for skin of the present invention is not particularly limited, and a known method can be appropriately used depending on the dosage form of the external preparation for skin. For example, there is a method of blending components (A), (B) and all other components and uniformly mixing them with a disper or the like. Alternatively, a method of blending all components other than water and an aqueous medium and uniformly mixing them with a disper or the like, then adding water and an aqueous medium and further stirring and mixing with a homogenizer or the like can also be used.
When the external preparation for skin is a water-in-oil emulsified composition or an oil-in-water emulsified composition, a method of preparing an aqueous phase and an oil phase and then mixing the two can also be used.

[Skin Infrared Protection Method]
The present invention also provides a method for protecting the skin from infrared rays, comprising the step of applying the external preparation for skin of the present invention to the skin.
The infrared protection method of the present invention is not particularly limited as long as it includes the step of applying the external preparation for skin of the present invention to the skin. Examples of the method of applying the skin external preparation to the skin include coating, spraying, and the like.

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

Regarding the above-described embodiments, the present invention further discloses the following external preparations for skin.
<1>
Component (A): The average particle size is 350 nm or more, preferably 400 nm or more, more preferably 700 nm or more, still more preferably 800 nm or more, and is 2,500 nm or less, preferably 2,000 nm or less, more preferably 1 , 800 nm or less, more preferably 1,500 nm or less, and even more preferably 1,200 nm or less, one or more metal oxides selected from the group consisting of spherical metal oxides (A1) and plate-shaped metal oxides (A2) and component (B): non-volatile oil, wherein the content of component (A) in the skin external preparation is 2% by mass or more, preferably 3% by mass or more, and more An external preparation for skin, which preferably contains 5% by mass or more and 50% by mass or less, and has a viscosity of 2,500 mPa·s or more at 25°C.
<2>
The metal oxide in component (A1) and component (A2) is preferably one or more selected from the group consisting of titanium oxide, zinc oxide, zirconium oxide, iron oxide, aluminum oxide, and cerium oxide, <1 >.
<3>
Viscosity at 25°C is preferably 2,500 mPa s or more and 150,000 mPa s or less, more preferably 2,500 mPa s or more and 100,000 mPa s or less, still more preferably 2,500 mPa s or more and 50,000 mPa s. s or less, more preferably 2,500 mPa s or more and 30,000 mPa s or less, still more preferably 2,500 mPa s or more and 20,000 mPa s or less, the skin according to <1> or <2> External agent.
<4>
The viscosity (mPa s) of the external skin preparation relative to the content (% by mass) of the component (A) in the external skin preparation is preferably 100 or more, more preferably 250 or more, still more preferably 300 or more, and more more preferably 350 or more, preferably 25,000 or less, more preferably 20,000 or less, even more preferably 15,000 or less, even more preferably 10,000 or less, still more preferably 5,000 or less , and more preferably 3,000 or less, the external preparation for skin according to any one of <1> to <3>.
<5>
The viscosity (mPa s) of the external skin preparation relative to the content (% by mass) of the component (A) in the external skin preparation is preferably 100 or more and 25,000 or less, more preferably 250 or more and 20,000 or less. , More preferably 300 or more and 15,000 or less, still more preferably 350 or more and 10,000 or less, still more preferably 350 or more and 5,000 or less, still more preferably 350 or more and 3,000 or less, <1> ~ The skin external preparation according to any one of <4>.
<6>
The content of the component (A) in the non-volatile components of the external preparation for skin is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, and preferably 50% by mass. % or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, still more preferably 20% by mass or less, the external preparation for skin according to any one of <1> to <5>.
<7>
The content of component (A) in the non-volatile components of the external preparation for skin is preferably 3% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 40% by mass or less, and still more preferably 10% by mass or more and 30% by mass. % or less, more preferably 10% by mass or more and 20% by mass or less.
<8>
Component (A1) preferably has an average particle size of 400 nm or more and 2,000 nm or less, more preferably 700 nm or more and 2,000 nm or less, still more preferably 700 nm or more and 1,800 nm or less, still more preferably 700 nm or more and 1,500 nm or less, The external preparation for skin according to any one of <1> to <7>, which is more preferably 800 nm or more and 1,200 nm or less.
<9>
The component (A) preferably contains a spherical metal oxide having an average particle size of 700 nm or more and 2,500 nm or less as the component (A1), and preferably has a viscosity of 2,500 mPa s or more and 20,000 mPa s or less at 25°C. The skin external preparation according to any one of <1> to <8>.
<10>
The skin external application according to any one of <1> to <9>, wherein the component (A) contains, as component (A2), preferably one or more selected from the group consisting of plate-like titanium oxide and plate-like zinc oxide. agent.
<11>
The thickness of the component (A2) is preferably 30 nm or more, more preferably 50 nm or more, still more preferably 60 nm or more, still more preferably 75 nm or more, still more preferably 90 nm or more, still more preferably 100 nm or more, Also, preferably 360 nm or less, more preferably 330 nm or less, still more preferably 310 nm or less, still more preferably 280 nm or less, even more preferably 270 nm or less, even more preferably 230 nm or less, still more preferably 200 nm or less, still more preferably 200 nm or less. The skin external preparation according to any one of <1> to <10>, which is 180 nm or less.
<12>
The thickness of component (A2) is preferably 30 nm or more and 360 nm or less, more preferably 50 nm or more and 330 nm or less, still more preferably 60 nm or more and 310 nm or less, still more preferably 75 nm or more and 280 nm or less, still more preferably 90 nm or more and 270 nm or less, The external preparation for skin according to any one of <1> to <11>, which is more preferably 100 nm or more and 230 nm or less, still more preferably 100 nm or more and 200 nm or less, still more preferably 100 nm or more and 180 nm or less.
<13>
The aspect ratio of the component (A2) is preferably 3 or more, more preferably 5 or more, still more preferably 10 or more, still more preferably 30 or more, still more preferably 50 or more, still more preferably 55 or more, Also, preferably 300 or less, more preferably 230 or less, still more preferably 200 or less, still more preferably 140 or less, still more preferably 125 or less, still more preferably 120 or less, <1> to <12> The skin external preparation according to any one of the above.
<14>
The aspect ratio of the component (A2) is preferably 3 or more and 300 or less, more preferably 3 or more and 230 or less, still more preferably 10 or more and 230 or less, still more preferably 30 or more and 230 or less, still more preferably 50 or more and 200 or less. , More preferably 55 or more and 140 or less, still more preferably 55 or more and 125 or less, still more preferably 55 or more and 120 or less, <1> to <13>.
<15>
The content of component (A2) in component (A) is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, still more preferably 80% by mass or more, and even more preferably is 90% by mass or more and 100% by mass or less, the skin external preparation according to any one of <1> to <14>.
<16>
The content of spherical titanium oxide having an average particle size of 350 nm or more and less than 800 nm in the skin external preparation is preferably 5% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 25% by mass or less. The skin external preparation according to any one of <15>.
<17>
The content of spherical titanium oxide having an average particle size of 800 nm or more and 2,500 nm or less in the external preparation for skin is preferably 5% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 30% by mass or less, <1 The skin external preparation according to any one of > to <16>.
<18>
The external preparation for skin according to any one of <1> to <17>, wherein the content of the plate-like titanium oxide in the external preparation for skin is preferably 5% by mass or more and 30% by mass or less.
<19>
The content of spherical zinc oxide or plate-shaped zinc oxide having an average particle size of 350 nm or more and 2,500 nm or less in the skin external preparation is preferably 7% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 50% by mass. The skin external preparation according to any one of <1> to <18> below.
<20>
The viscosity of component (B) at 25° C. is preferably 500 mPa·s or less, more preferably 300 mPa·s or less, still more preferably 100 mPa·s or less, still more preferably 50 mPa·s or less, and preferably 5 mPa. · The external preparation for skin according to any one of <1> to <19>, which is s or more.
<21>
The component (B) is preferably liquid at 25° C., more preferably one or more selected from the group consisting of ester oils, silicone oils, hydrocarbon oils, higher fatty acids, and higher alcohols, <1> The skin external preparation according to any one of <20>.
<22>
The content of component (B) in the external preparation for skin is preferably 1% by mass or more, more preferably 5% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, and still more preferably. is 70% by mass or less, more preferably 65% by mass or less.
<23>
The topical skin preparation is a water-in-oil emulsion composition, and the content of component (B) in the topical skin preparation is preferably 15% by mass or more, more preferably 20% by mass or more, and still more preferably 25% by mass or more. , More preferably 30% by mass or more, still more preferably 35% by mass or more, <1> to <22>.
<24>
The topical skin preparation is an oil-in-water emulsified composition, and the content of component (B) in the topical skin preparation is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less. The skin external preparation according to any one of <1> to <23>.
<25>
The mass ratio of the content of component (B) to the content of component (A) [(B)/(A)] is preferably 0.05 or more, more preferably 0.1 or more, and still more preferably 0.2 more preferably 0.5 or more, still more preferably 1 or more, still more preferably 2 or more, still more preferably 3 or more, still more preferably 3.6 or more, and preferably 60 or less, The external skin treatment according to any one of <1> to <24>, which is more preferably 50 or less, still more preferably 30 or less, still more preferably 20 or less, still more preferably 10 or less, and even more preferably 8 or less. agent.
<26>
The mass ratio of the content of component (B) to the content of component (A) [(B)/(A)] is preferably 0.05 or more and 60 or less, more preferably 0.1 or more and 50 or less, and still more preferably is 0.2 or more and 30 or less, more preferably 0.5 or more and 20 or less, still more preferably 1 or more and 10 or less, still more preferably 2 or more and 10 or less, still more preferably 3 or more and 10 or less, still more preferably The skin external preparation according to any one of <1> to <25>, which is 3.6 or more and 8 or less.
<27>
The total content of component (A) and component (B) in the external skin preparation is preferably 2% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, and even more preferably 30% by mass. More preferably 40% by mass or more, still more preferably 45% by mass or more, still more preferably 47% by mass or more, still more preferably 50% by mass or more, and 100% by mass or less <1> to <26>, the external preparation for skin.
<28>
The external preparation for skin according to any one of <1> to <27>, which preferably further contains a thickening agent.
<29>
The external preparation for skin according to <28>, wherein the thickener is preferably an oil thickener.
<30>
The skin according to <28> or <29>, wherein the thickener is preferably one or more selected from the group consisting of solid waxes, organically modified clay minerals, dextrin fatty acid esters, and amino acid gelling agents. External agent.
<31>
The content of the thickening agent in the external preparation for skin is preferably 0.5% by mass or more, more preferably 1% by mass or more, still more preferably 2% by mass or more, and even more preferably 3% by mass or more. , Also preferably 50% by mass or less, more preferably 30% by mass or less, still more preferably 25% by mass or less, even more preferably 20% by mass or less, still more preferably 15% by mass or less <28> ~ The skin external preparation according to any one of <30>.
<32>
The content of the thickening agent in the external preparation for skin is preferably 0.5% by mass or more and 50% by mass or less, more preferably 0.5% by mass or more and 30% by mass or less, and still more preferably 1% by mass or more and 25% by mass. % or less, more preferably 2 to 20 mass %, still more preferably 3 to 15 mass %, the external preparation for skin according to any one of <28> to <31>.
<33>
The external skin preparation preferably further contains water, and the content of water in the external skin preparation is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 8% by mass or more, and even more preferably. is 10% by mass or more, preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less.
<34>
The external preparation for skin according to any one of <1> to <33>, which is preferably liquid, gel, cream or solid.
<35>
The external preparation for skin according to any one of <1> to <34>, which is for protection against ultraviolet rays or infrared rays, suppression of skin temperature rise, or suppression of fatigue.
<36>
A method for protecting the skin from infrared rays, comprising the step of applying the external preparation for skin according to any one of <1> to <35> to the skin, preferably by coating or spraying.
<37>
The infrared protection method for skin according to <36>, wherein the infrared protection rate at a wavelength of 825 nm is preferably 35% or higher, more preferably 45% or higher, even more preferably 55% or higher, and even more preferably 65% or higher.
<38>
Use of the external preparation for skin according to any one of <1> to <34> as an ultraviolet protective agent, an infrared protective agent, an agent for suppressing skin temperature rise, or an agent for suppressing fatigue.

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 addition, in the present Examples, various measurements and evaluations were performed by the following methods.

<Viscosity>
The viscosity at 25° C. of each example of the external preparation for skin was measured using a Brookfield viscometer ("TOKI SANGYO VISCOMETER TVB-10M" manufactured by Toki Sangyo Co., Ltd.) at a rotor speed of 6.0 rpm and a rotation time of 60 seconds. Under these conditions, measurements were made on the next day after preparation of the external preparation for skin. The rotor is No. 1 depending on the viscosity. 2-No. 4 was used. [No. 2: Viscosity 500-5000 mPa·s, No. 3: Viscosity more than 5000 mPa·s and 20000 mPa·s or less, No. 4: Viscosity over 20000 mPa s]

<Near-infrared protection rate>
50.0 mg of the external skin preparation of each example is applied to a 5 cm × 5 cm polymethyl methacrylate (PMMA) substrate (“SPF Matser PA-1” manufactured by Fuji Kasei Co., Ltd.), dried for 15 minutes, and used for measurement. was used as a sample. Similarly, an uncoated PMMA substrate was used as a control sample. The transmittance at a wavelength of 825 nm was measured for each of the measurement sample and the control sample using a near-infrared microscope. The value obtained by dividing the transmittance of the measurement sample by the transmittance of the control sample was defined as the transmittance X (%), and 100-X (%) was defined as the near-infrared protection rate. A larger value means that the external preparation for skin has a higher near-infrared protective effect.

In addition, the near-infrared protective effect was evaluated in 5 stages according to the following criteria.
(Evaluation criteria)
5: Near-infrared protection rate is 65.0% or more 4: Near-infrared protection rate is 55.0% or more and less than 65.0% 3: Near-infrared protection rate is 45.0% or more and less than 55.0% 2: Near infrared rays Protection rate is 35.0% or more and less than 45.0% 1: Near infrared protection rate is less than 35.0%

<Coating film uniformity>
On a polymethyl methacrylate (PMMA) substrate of 5 cm x 5 cm, each external preparation for skin was uniformly applied to 2 mg/cm ² and dried at 25°C for 15 minutes.
Using a near-infrared microscope (IR microscope), the transmittance distribution at a wavelength of 825 nm was photographed for the substrate on which the external preparation for skin was applied. From this distribution image, the transmittance distribution of the corniculus part (the convex part of the PMMA plate) and the transcutaneous part (the concave part of the PMMA plate) was confirmed, and the uniformity was evaluated as "only the sulcus cutis is protected." The evaluation was made on a 5-point scale, with 1 point for the case where the skin bumps were almost completely protected, and 5 points for the case where both the skin bumps and the skin folds were evenly protected.
(Evaluation criteria)
1: Only the sulcus cutis is protected, and the corniculus is hardly protected 2: The sulcus cutis is protected, and the sulcus cutis is slightly protected 3: The sulcus cutis is protected 4: sulcus cutis protected, and sulcus cutis well protected

<Whitening when applied to the skin>
Approximately 0.09 g of each topical skin preparation was applied to an area of approximately 3 cm x 3 cm on the inner side of the forearm of the expert panelist. Evaluation was made on a scale of 5, with 5 points indicating no discomfort in whiteness. Evaluation was performed by three expert panelists, and the average score was used as the evaluation result.
(Evaluation criteria)
1: Very white, feels very unnatural 2: Slightly white, feels unnatural 3: Neither 4: Natural whiteness, but slightly uncomfortable 5: Natural whiteness, no discomfort

<Skin temperature rise suppression effect>
About 3.2 g of the external skin preparations of Example 6 and Comparative Example 5 were evenly applied to an area of about 4 cm x 4 cm on the inside of the forearm of a professional panelist, and dried for 15 minutes at 25°C and 40% RH. After that, using a solar simulator (“HAL-320W” manufactured by Asahi Spectrosco Co., Ltd.), the application site was irradiated with simulated sunlight for 5 minutes from a distance of 24 cm.
A thermocamera (“T-420” manufactured by FLIR) was used to measure changes in skin temperature during irradiation. By the same method, the temperature rise when the topical skin preparation was not applied was also measured, and (Temperature rise when the topical skin preparation was not applied (°C)) - (Temperature rise when the topical skin preparation was applied (°C)). are shown in the table. A larger value means that the effect of suppressing a rise in skin temperature is higher.

Examples 1 to 23, Comparative Examples 1 to 6 (manufacture and evaluation of external preparations for skin)
Of the components shown in Tables 1 to 4, all components except water were blended and uniformly mixed with a disper. Then, water was added to the resulting mixed solution and mixed uniformly using a homogenizer to produce a water-in-oil type external preparation for skin having the composition shown in Tables 1 to 4. The resulting external preparation for skin was evaluated by the method described above. The results are shown in Tables 1-4. In addition, the compounding quantity described in each table|surface is the amount of active ingredients (mass %) of each component except "BENTONE GEL PTM V." The blending amount of "BENTONE GEL PTM V" is mass % in the actual state. In the table, a metal oxide that does not correspond to component (A) is indicated as "component (A1')".

Examples 24 to 27 (manufacture of external preparation for skin)
For Examples 24 and 25, among the components shown in Table 5, all components except water were blended and uniformly mixed with a disper. Next, water was added to the resulting mixed solution and mixed uniformly using a homogenizer to produce a water-in-oil type solid skin preparation for external use having the composition shown in Table 5. For Examples 26 and 27, all the components shown in Table 5 were blended and uniformly mixed with a disper to produce a solid external preparation for skin. In addition, the compounding quantity described in the table|surface is the active-ingredient amount (mass %) of each component.

The ingredients in the table are as follows.
*1: “R-38L” manufactured by Sakai Chemical Industry Co., Ltd., ZrO ₂ —Al ₂ O ₃ coated spherical titanium oxide, average particle size 400 nm
*2: "ST-750EC" manufactured by Titan Kogyo Co., Ltd. Aluminum hydroxide-hydrogen dimethicone coated spherical titanium oxide, average particle size 1,000 nm
*3: “LP-ZINC-2KS” manufactured by Sakai Chemical Industry Co., Ltd. Hydrogen dimethicone-coated spherical zinc oxide, average particle size 2,000 nm
*4: “JR800s” manufactured by Tayka Co., Ltd. Hydrogen dimethicone-coated spherical titanium oxide, average particle size 270 nm
* 5: Made by Daito Kasei Kogyo Co., Ltd., plate-shaped titanium oxide ("Featheleve PT-7801K" made by CQV) surface ASC-treated product, thickness 134 nm, aspect ratio 95
* 6: Made by Daito Kasei Kogyo Co., Ltd., plate-shaped titanium oxide ("Featheleve PT-7401K" made by CQV) surface ASC-treated product, thickness 112 nm, aspect ratio 126
* 7: Made by Daito Kasei Kogyo Co., Ltd., plate-shaped titanium oxide ("Featheleve PT-7901K" made by CQV) surface ASC-treated product, thickness 191 nm, aspect ratio 58
*8: “XZ-1000F-LP” manufactured by Sakai Chemical Industry Co., Ltd., plate-shaped zinc oxide coated with hydrogen dimethicone, thickness 290 nm, aspect ratio 3.4
* 9: "Exepar IPP" manufactured by Kao Corporation, isopropyl palmitate * 10: "KF-96L-10cs" manufactured by Shin-Etsu Chemical Co., Ltd., dimethicone, viscosity 10 mPa s
*11: "BENTONE GEL PTM V" manufactured by Elementis, caprylic acid/capric acid triglyceride, stearalkonium hectorite and propylene carbonate, non-volatile component 96.8% by mass (measured value)
*12: "Leopearl KL2" manufactured by Chiba Flour Milling Co., Ltd., dextrin palmitate *13: "DOWSIL AMS-C30 COSMETIC WAX" manufactured by Dow Toray Industries, Inc., alkyl (C30-45) methicone *14: Shin-Etsu Chemical Co., Ltd. ( "Silicone KF-6028" manufactured by Kao Corporation, "Silicone KF-6028", PEG-9 polydimethylsiloxyethyl dimethicone *15: "OS-88E-TV-E" manufactured by Kao Corporation, N-propionylpolyethyleneimine-methylpolysiloxane copolymer (30 % by mass-ethanol solution)
*16: “EB-21” manufactured by Ajinomoto Co., Inc., dibutylethylhexanoyl glutamide *17: “HNP-9” manufactured by Nippon Seiro Co., Ltd., paraffin wax, melting point: 80 ° C.
*18: "Ceresin #810K" manufactured by Nikko Rica Co., Ltd., ceresin, melting point: 74°C

From Tables 1 to 4, it can be seen that the external preparation for skin of this example has a high infrared protection effect and a high coating uniformity, and causes little whitening when applied to the skin. In addition, it is also excellent in skin temperature rise suppressing effect.

In addition, FIG. 1 shows an IR microscope observation photograph (score 5) in the coating film uniformity evaluation of the external skin preparation of Example 9, and FIG. An observation photograph (score 1) by an IR microscope is shown. In FIGS. 1 and 2, white portions indicate locations where component (A) is present, and black portions indicate locations where component (A) is not present. When the topical skin preparation of Example 9 was applied, a large amount of component (A) was present not only in the sulcus cutis but also in the carpus (Fig. 1), whereas the topical skin preparation of Comparative Example 2 was applied. In this case, most of the component (A) fell into the sulci, indicating that the uniformity of the coating film was low (Fig. 2).

Claims

Component (A): one or more metal oxides selected from the group consisting of spherical metal oxides (A1) and plate-like metal oxides (A2) having an average particle size of 350 nm or more and 2,500 nm or less, and component (B) : non-volatile oil,
A skin external preparation containing
The content of component (A) in the external preparation for skin is 2% by mass or more and 50% by mass or less,
An external skin preparation having a viscosity of 2,500 mPa·s or more at 25°C.
The external preparation for skin according to claim 1, wherein the viscosity (mPa·s) of the external preparation for skin relative to the content (% by mass) of the component (A) in the preparation for external use for skin is 100 or more.
The external preparation for skin according to claim 1 or 2, wherein the content of said component (A) in the non-volatile components of said external preparation for skin is 50% by mass or less.
The skin external preparation according to any one of claims 1 to 3, wherein the component (A) contains plate-like titanium oxide as the component (A2).
The external preparation for skin according to claim 4, wherein the content of the plate-like titanium oxide in the external preparation for skin is 5% by mass or more and 30% by mass or less.
The skin external preparation according to any one of claims 1 to 5, wherein the component (A2) has a thickness of 30 nm or more and 360 nm or less.
The skin external preparation according to any one of claims 1 to 6, wherein the component (A2) has an aspect ratio of 3 or more and 300 or less.
The component (A) contains a spherical metal oxide having an average particle size of 700 nm or more and 2,500 nm or less as the component (A1), and has a viscosity of 2,500 mPa·s or more and 20,000 mPa·s or less at 25°C. The skin external preparation according to any one of 1 to 7.
The external preparation for skin according to any one of claims 1 to 8, wherein the component (B) is one or more selected from the group consisting of ester oils, silicone oils, hydrocarbon oils, higher fatty acids, and higher alcohols. .
The external preparation for skin according to any one of claims 1 to 9, further comprising a thickening agent.
The skin external preparation according to claim 10, wherein the thickener is an oil thickener.
The skin external preparation according to claim 11, wherein the oil thickener is one or more selected from the group consisting of solid waxes, organically modified clay minerals, dextrin fatty acid esters, and amino acid-based gelling agents.
The external preparation for skin according to any one of claims 10 to 12, wherein the content of said thickening agent in said external preparation for skin is 0.5% by mass or more and 50% by mass or less.
The external preparation for skin according to any one of claims 1 to 13, which further contains water.
The external skin preparation according to any one of claims 1 to 14, wherein the skin external preparation is solid.
The external preparation for skin according to any one of claims 1 to 15, which is for protecting against ultraviolet rays or infrared rays, for suppressing skin temperature rise, or for suppressing fatigue.
A method for protecting the skin from infrared rays, comprising applying the external preparation for skin according to any one of claims 1 to 16 to the skin.