CN114727920A

CN114727920A - External preparation for skin

Info

Publication number: CN114727920A
Application number: CN202080079384.4A
Authority: CN
Inventors: 手岛典子; 武谷真由美
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 2019-11-20
Filing date: 2020-11-17
Publication date: 2022-07-08
Also published as: TW202128123A; KR20220080162A; JP2021080251A; WO2021100676A1

Abstract

The present invention is an external preparation for skin, which is obtained by blending (a) a plate-like metal oxide having a thickness of 100nm to 120 nm; (b) a plate-like metal oxide having a thickness of 125nm to 145 nm; and (c) a plate-like metal oxide having a thickness of 180nm or more and 200nm or less, wherein the amount of the component (a) is 5% by mass or more and 70% by mass or less, the amount of the component (b) is 15% by mass or more and 75% by mass or less, and the amount of the component (c) is 5% by mass or more and 70% by mass or less, based on 100% by mass of the total amount of the components (a) to (c).

Description

External preparation for skin

Technical Field

The present invention relates to an external preparation for skin.

Background

From the viewpoint of skin protection against sunlight, ultraviolet protection cosmetics such as sunscreen cosmetics are known. On the other hand, in recent years, due to the increase in health consciousness, there is a demand for external preparations for skin having a function of protecting against infrared rays.

As an external preparation for skin having an infrared ray shielding function, for example, patent document 1 (international publication No. 2009/017104) discloses a near-infrared ray damage preventing agent for living tissue containing an infrared ray penetration shielding agent composed of titanium oxide powder and zinc oxide powder as a technique for preventing infrared ray from reaching dermis or hypodermis deeper than skin tissue and preventing damage to these tissues due to infrared ray. Further, patent document 2 (japanese patent laid-open No. 2017-95361) discloses a near-infrared ray protection cosmetic composition comprising a titanium oxide powder and a zinc oxide powder, which has both an excellent near-infrared ray protection effect and high transparency.

Disclosure of Invention

The present invention relates to the following [1] and [2 ].

[1] A skin external preparation which is obtained by blending the following components (a) to (c),

(a) a plate-like metal oxide having a thickness of 100nm to 120 nm;

(b) a plate-like metal oxide having a thickness of 125nm to 145 nm; and

(c) a plate-like metal oxide having a thickness of 180nm to 200 nm;

the blending amount of the component (a) is 5 to 70 mass%, the blending amount of the component (b) is 15 to 75 mass%, and the blending amount of the component (c) is 5 to 70 mass%, with respect to 100 mass% of the total blending amount of the components (a) to (c).

[2] A method for protecting skin from infrared rays, wherein the skin external preparation according to [1] is applied to skin.

Drawings

Fig. 1 is a three-phase diagram showing the mass% of component (a), component (b), and component (c) in 100 mass% of the total amount of components (a) to (c) in the external preparation for skin.

Reference numerals:

1 … … the blending amount of component (a) is 5 to 70% by mass based on 100% by mass of the total blending amount of components (a) to (c); the amount of the component (b) is 15 to 75 mass%; and the blending amount of the component (c) is 5 to 70 mass%;

2 … … satisfies the composition region of condition 1;

3 … … satisfies the composition region of condition 2.

Detailed Description

[ skin external preparations ]

The skin external preparation of the present invention is obtained by blending the following components (a) to (c),

(a) a plate-like metal oxide having a thickness of 100nm to 120 nm;

(b) a plate-like metal oxide having a thickness of 125nm to 145 nm; and

(c) a plate-like metal oxide having a thickness of 180nm or more and 200nm or less,

The external preparation for skin of the present invention has the above-described configuration, and can provide a natural color tone which is excellent in infrared ray shielding effect and which blends with skin color when applied to the skin.

For skin protection, skin external preparations having further improved infrared ray protection function than the techniques disclosed in patent documents 1 and 2 are desired. Furthermore, in the skin external preparations, reddish or bluish as skin cosmetics, an unnatural color tone is obtained when applied to the skin, and thus natural color tones that blend with skin color are also required.

The invention provides a skin external preparation which has excellent infrared ray protection effect, is not easy to be considered to be reddish or bluish when being coated on the skin, and can obtain natural color tone which is blended with skin color.

The inventors of the present application have found that the above-mentioned problems can be solved by a skin preparation for external use prepared by combining plate-like metal oxides having a predetermined thickness range and different thicknesses at a predetermined ratio.

The external preparation for skin of the present invention has an excellent infrared ray shielding effect, is unlikely to be considered reddish or bluish when applied to the skin, and can give a natural color tone that is compatible with the skin color, and is useful, for example, as a skin cosmetic.

The thickness of the plate-like metal oxide in the present invention means the length of the shortest axis in the plate-like metal oxide particles.

In the present invention, infrared rays mean electromagnetic waves having a wavelength of 780nm to 1 mm. Among these, the external preparation for skin of the present invention is particularly excellent in the effect of protecting from near infrared rays having a wavelength of 780nm to 2500 nm. This can suppress the increase in skin temperature caused by irradiation with sunlight, and can provide a high heat-insulating feeling.

In the present specification, the infrared ray protection effect is represented by the infrared ray protection rate at a wavelength of 1500 nm.

The formulation of the external preparation for skin of the present invention is not particularly limited, and is preferably in the form of a liquid, gel, or cream, from the viewpoint of ease of application to the skin. The external preparation for skin may be in the form of an emulsion composition, and the emulsion composition may be either an oil-in-water emulsion composition or a water-in-oil emulsion composition.

The skin external preparation of the present invention is preferably a skin cosmetic such as a sunscreen cosmetic (lotion, cream, lotion, essence, etc.), a tanning agent, a makeup base, and the like.

< Components (a) to (c): plate-shaped metal oxide >

(a) a plate-like metal oxide having a thickness of 100nm to 120 nm;

(b) a plate-like metal oxide having a thickness of 125nm to 145 nm; and

(c) a plate-like metal oxide having a thickness of 180nm or more and 200nm or less.

The external preparation for skin of the present invention is excellent in infrared ray shielding effect, can provide a high heat-insulating feeling, and also exhibits an effect of being less likely to whiten and providing a natural color tone that blends with skin color when applied to the skin, by blending the predetermined plate-like metal oxides as components (a) to (c) in a predetermined ratio. The reason for this is not clear, but is considered as follows.

It is known that the use of inorganic particles having a relatively large particle diameter in an external preparation for skin containing inorganic particles such as titanium oxide also has an increased infrared ray shielding effect. However, there is a limit to improving the infrared ray shielding effect only by using inorganic particles having a large particle diameter. In addition, for example, when spherical inorganic particles having a particle diameter larger than the wavelength of visible light are formulated in an external preparation for skin, there is a disadvantage that the surface of the particles is easily whitened due to light scattering of visible light when applied to the skin.

In contrast, the present inventors have found that by using a plate-like metal oxide having a predetermined thickness as an infrared shielding agent for an external skin preparation, the reflectance of light in the infrared region can be selectively increased by the light interference effect, and the reflectance of light in the visible region can be decreased, thereby achieving both the infrared shielding effect and the effect of being less likely to whiten when applied to the skin.

On the other hand, it has been found that an external preparation for skin containing a plate-like metal oxide as an infrared ray shielding agent is considered to have reddish or bluish color when applied to the skin, and may have an unnatural color tone that does not blend with the skin. In view of such a problem, the present inventors have found that by blending the components (a) to (c) of the plate-like metal oxides having different thicknesses at the above-mentioned predetermined ratio, both a high infrared ray shielding effect and a natural color tone when applied to the skin can be achieved. Regarding the color tone, the components (a) to (c) exhibit interference colors of red, blue and green, respectively, due to the wavelength of reflected light, but it is considered that a natural color tone which blends with skin color when applied to the skin can be obtained by setting the blending amount of each component to a predetermined range.

From the viewpoint of obtaining an excellent infrared ray shielding effect by the above action mechanism and from the viewpoint of being less likely to whiten when the external preparation for skin is applied to the skin and obtaining a natural color tone, the thicknesses of the components (a) to (c) are preferably in the following ranges, respectively.

The thickness of the component (a) is 100nm or more, preferably 105nm or more, and 120nm or less, preferably 115nm or less. The component (a) having a thickness in the above range exhibits a reddish interference color derived from the wavelength of the reflected light.

The thickness of the component (b) is 125nm or more, preferably 130nm or more, and 145nm or less, preferably 140nm or less. The component (b) having a thickness in the above range exhibits an interference color bluish from the wavelength of the reflected light.

The thickness of the component (c) is 180nm or more, preferably 185nm or more, and 200nm or less, preferably 195nm or less. The component (c) having a thickness in the above range exhibits an interference color that is greenish due to the wavelength of the reflected light.

The thicknesses of the components (a) to (c) can be determined from observation images obtained by a Scanning Electron Microscope (SEM). Specifically, the plate-like metal oxides of the components (a) to (c) were observed under the condition of an observation magnification of 10,000 times by SEM, the thicknesses of 50 particles in the observation image were measured, and the average value of the thicknesses per unit number was calculated. The thicknesses of the components (a) to (c) can be measured specifically by the methods described in examples.

From the viewpoint of reducing glare when the external preparation for skin is applied to the skin, the average particle diameter of the components (a) to (c) is preferably 20 μm or less, more preferably 15 μm or less, more preferably 12 μm or less, and still more preferably 10 μm or less. On the other hand, from the viewpoint of obtaining an excellent infrared ray shielding effect and from the viewpoint of being less likely to whiten when the external preparation for skin is applied to the skin and obtaining a natural color tone, the average particle size of the components (a) to (c) is preferably 1 μm or more, more preferably 2 μm or more, more preferably 3 μm or more, and still more preferably 5 μm or more. The specific range of the average particle diameter of the components (a) to (c) is preferably 1 μm or more and 20 μm or less, more preferably 2 μm or more and 15 μm or less, more preferably 2 μm or more and 12 μm or less, still more preferably 3 μm or more and 10 μm or less, and still more preferably 5 μm or more and 10 μm or less.

The average particle diameter of the components (a) to (c) is a median diameter (D50) measured by a laser diffraction/scattering particle size distribution measuring apparatus in terms of a particle diameter reference volume, and can be measured specifically by the method described in examples.

From the viewpoint of obtaining an excellent infrared ray shielding effect and from the viewpoint of obtaining a natural color tone when the external preparation for skin is applied to the skin, the aspect ratio of the components (a) to (c) is preferably 10 or more, more preferably 20 or more, more preferably 30 or more, and still more preferably 35 or more. From the viewpoint of obtaining an excellent infrared ray shielding effect and from the viewpoint of being less likely to whiten and reducing glare when the external preparation for skin is applied to the skin, it is preferably 200 or less, more preferably 150 or less, more preferably 100 or less, and still more preferably 90 or less. The specific range of the aspect ratio of the components (a) to (c) is preferably 10 or more and 200 or less, more preferably 10 or more and 150 or less, more preferably 10 or more and 100 or less, still more preferably 20 or more and 100 or less, still more preferably 30 or more and 100 or less, and still more preferably 35 or more and 90 or less.

The aspect ratio of the components (a) to (c) can be calculated from (average particle diameter/thickness).

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

The higher the refractive index of the metal oxide constituting the components (a) to (c), the higher the light interference effect of the material can be obtained. From this viewpoint, preferable metal oxides as the constituent components (a) to (c) include, for example, titanium oxide, zinc oxide, zirconium oxide, iron oxide, aluminum oxide, cerium oxide, and the like. Among these, 1 or more selected from titanium oxide and zinc oxide are preferable, and titanium oxide is more preferable. That is, the components (a) to (c) are preferably 1 or more selected from the group consisting of plate-like titanium oxide and plate-like zinc oxide, and more preferably plate-like titanium oxide.

The crystal structure of titanium oxide may be any of rutile type, anatase type, and amorphous type, and rutile type is preferable from the viewpoint of obtaining excellent infrared ray shielding effect and heat insulating feeling.

The plate-like metal oxides of the components (a) to (c) may be not subjected to surface treatment, but may be subjected to surface treatment such as hydrophobic treatment by a known method as needed in order to improve dispersibility in the skin preparation for external use. The plate-like metal oxides of the components (a) to (c) are different from those obtained by surface-treating the surfaces of particles other than the metal oxides with a metal oxide.

Examples of the surface treatment agent used for the surface treatment of the plate-like metal oxide of the components (a) to (c) include: a silicone; an alkylalkoxysilane; fluorine-containing compounds such as perfluoroalkyl phosphate and perfluoroalcohol; amino acids such as N-acyl glutamic acid; and lecithin; a metal soap; fatty acids such as stearic acid; alkyl phosphates, and the like. Among these, from the viewpoint of improving dispersibility of the components (a) to (c) in the external preparation, 1 or more selected from silicone and alkylalkoxysilane is preferable.

The silicone as the surface treatment agent is not particularly limited, and examples thereof include: various silicone oils (silicone oils) such as methyl polysiloxane, dimethyl polysiloxane, methylphenyl polysiloxane, methylhydrogenpolysiloxane, methylcyclopolysiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, octamethyltrisiloxane, tetradecmethylhexasiloxane, dimethylsiloxane-methyl (polyoxyethylene) siloxane-methyl (polyoxypropylene) siloxane copolymer, dimethylsiloxane-methyl (polyoxyethylene) siloxane copolymer, dimethylsiloxane-methyl (polyoxypropylene) siloxane copolymer, dimethylsiloxane-methylhexadecyloxysiloxane copolymer, dimethylsiloxane-methyloctadecyloxysiloxane copolymer, and alkyl acrylate/polydimethylsiloxane copolymer.

The alkylalkoxysilane as the surface treatment agent is preferably one having a branched or linear alkyl group having 6 to 20 carbon atoms, and examples thereof include octyltriethoxysilane and octyltrimethoxysilane.

From the viewpoint of enhancing the infrared ray shielding effect, the surface treatment agent is preferably at least 1 selected from the group consisting of methyl polysiloxane, dimethyl polysiloxane, methyl hydrogen polysiloxane, an alkyl acrylate/polydimethylsiloxane copolymer, and octyl triethoxysilane.

In the external preparation for skin of the present invention, the amount of the component (a) is 5% by mass or more and 70% by mass or less, the amount of the component (b) is 15% by mass or more and 75% by mass or less, and the amount of the component (c) is 5% by mass or more and 70% by mass or less, based on 100% by mass of the total amount of the components (a) to (c). When the amount of each component is in the above range with respect to 100% by mass of the total amount of components (a) to (c), an excellent infrared ray shielding effect and a natural color tone when the external skin preparation is applied to the skin can be achieved at the same time. Among these, it was found that, with respect to the infrared ray shielding effect, when the blending amount of the component (a) is 70 mass% or less with respect to 100 mass% of the total blending amount of the components (a) to (c), an excellent infrared ray shielding effect can be obtained.

The external preparation for skin of the present invention preferably satisfies the following condition 1, more preferably satisfies the following condition 2, with respect to 100 mass% of the total amount of the components (a) to (c) to be blended, from the viewpoint of achieving both an excellent infrared ray shielding effect and a natural color tone when the external preparation for skin is applied to the skin.

Condition 1: in a three-phase diagram showing the mass% of the components (a), (b) and (c) relative to 100 mass% of the total amount of the components (a) to (c), the amount of each component is within a composition region surrounded by 6 composition points as shown below,

(a,b,c)＝(70,15,15)、(28,26,46)、(5,40,55)、(5,67,28)、(20,68,12)、(57,33,10)；

condition 2: in a three-phase diagram showing the mass% of the component (a), the component (b) and the component (c) in 100 mass% relative to the total amount of the components (a) to (c), the blending ratio of each component is within a composition region surrounded by 6 composition points shown below,

(a,b,c)＝(50,28,22)、(25,45,30)、(25,32,43)、(15,43,42)、(23,55,22)、(42,43,15)。

the above conditions 1 and 2 are explained with reference to the drawings.

Fig. 1 is a three-phase diagram showing the mass% of component (a), component (b), and component (c) in 100 mass% of the total amount of components (a) to (c) in the external preparation for skin. In the three-phase diagram of fig. 1, a region 1 surrounded by a thick solid line represents a composition region in which the blending amount of the component (a) is 5 mass% or more and 70 mass% or less, the blending amount of the component (b) is 15 mass% or more and 75 mass% or less, and the blending amount of the component (c) is 5 mass% or more and 70 mass% or less, with respect to 100 mass% of the total blending amount of the components (a) to (c).

A region 2 surrounded by a broken line in the three-phase diagram of fig. 1 is a composition region satisfying the above condition 1. In fig. 1, 6 component points of (a, b, c) ═ 70,15,15), (28,26,46), (5,40,55), (5,67,28), (20,68,12), (57,33,10) are indicated by "∘".

A region 3 surrounded by a broken line in the three-phase diagram of fig. 1 is a composition region satisfying the above condition 2. In fig. 1, 6 composition points of (a, b, c) ═ 50,28,22), (25,45,30), (25,32,43), (15,43,42), (23,55,22), (42,43,15) are denoted by "Δ".

The total amount of the components (a) to (c) in the external preparation for skin of the present invention is preferably 1% by mass or more, more preferably 1.5% by mass or more, and still more preferably 2% by mass or more, from the viewpoint of obtaining an excellent infrared ray shielding effect. From the viewpoint of being less likely to whiten and obtaining a natural color tone when the external preparation for skin is applied to the skin, and from the viewpoint of economy, the external preparation for skin is preferably 35% by mass or less, more preferably 25% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less, and still more preferably 10% by mass or less. The specific range of the total amount of components (a) to (c) in the external preparation for skin of the present invention is preferably 1% by mass or more and 35% by mass or less, more preferably 1% by mass or more and 25% by mass or less, more preferably 1% by mass or more and 20% by mass or less, still more preferably 1% by mass or more and 15% by mass or less, still more preferably 1.5% by mass or more and 10% by mass or less, and still more preferably 2% by mass or more and 10% by mass or less.

The skin external preparation of the present invention does not exclude the plate-like metal oxide other than the components (a) to (c) to be formulated, and it is preferable that the amount to be formulated is small from the viewpoint of obtaining the effects of the present invention. Specifically, the proportion of the components (a) to (c) in the total amount of the plate-like metal oxide to be blended in the external preparation for skin is preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and 100% by mass or less.

As the components (a) to (c), commercially available plate-like metal oxides can also be used. Examples of commercially available plate-like titanium oxides include "Featherve PT-9001K", "Featherve PT-7001K", "Featherve PT-7401K", "Feathere PT-7801K" and "Feathere PT-7901K" manufactured by CQV, for example. These plate-like titanium oxides are more preferably those having undergone the above surface treatment as components (a) to (c).

When the aspect ratio or average particle diameter of the plate-like metal oxide is adjusted to the above range, commercially available plate-like metal oxides or surface-treated products thereof may be pulverized by a pulverizer and used as the components (a) to (c). The method of the pulverization treatment is not particularly limited, and a known method can be used. When the plate-like metal oxide having been subjected to the surface treatment is used, the pulverization treatment may be carried out at any stage of before the surface treatment and after the surface treatment.

< ingredient (d): touch feeling improver >

The external preparation for skin of the present invention preferably further contains a touch feeling enhancer as the component (d) from the viewpoint of suppressing stickiness when applied to the skin and obtaining a refreshing and good touch feeling when an oil agent or the like described later is blended.

The feel improver may be any of organic particles, inorganic particles other than the components (a) to (c), and mixtures thereof, and may be those generally used in cosmetics. The particle shape is preferably spherical from the viewpoint of obtaining a good touch when applied to the skin. In addition, a substance having irregularities on the surface of the particles or a porous substance may be used.

Examples of the organic particles used as the component (d) include resin particles made of resins such as acrylic resin, silicone resin, polystyrene resin, polyamide resin, polyester resin, polyolefin resin, polystyrene resin, polyurethane resin, vinyl resin, urea resin, phenol resin, fluorine resin, melamine resin (melamine resin), epoxy resin, polycarbonate resin, acrylic-silicone copolymer resin, acrylic-styrene copolymer resin, and cellulose. These resin particles may be crosslinked resin particles or non-crosslinked resin particles.

As the inorganic particles other than the components (a) to (c), metal oxide particles are preferable, and examples of the metal oxide include titanium oxide, zinc oxide, zirconium oxide, iron oxide, aluminum oxide, cerium oxide, and the like. Among these, 1 or more selected from titanium oxide and zinc oxide are preferable, and titanium oxide is more preferable.

Among the above, the component (d) is preferably a spherical inorganic particle, more preferably a spherical metal oxide particle, more preferably 1 or more selected from a spherical titanium oxide particle and a spherical zinc oxide particle, and still more preferably a spherical titanium oxide particle.

From the viewpoint of suppressing stickiness upon application to the skin and obtaining a good feel, the average particle diameter of the particles used as the component (d) is preferably 0.1 μm or more, more preferably 0.2 μm or more, and still more preferably 0.5 μm or more. From the viewpoint of suppressing stickiness when applied to the skin and obtaining a good feel, and from the viewpoint of being less likely to whiten when applied to the skin, the external preparation for skin is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 2 μm or less. The specific range of the average particle diameter of the particles used as the component (d) is preferably 0.1 μm or more and 10 μm or less, more preferably 0.2 μm or more and 5 μm or less, and still more preferably 0.5 μm or more and 2 μm or less. The average particle diameter can be measured by the same method as described above.

When the component (d) is used in the external preparation for skin of the present invention, the content thereof is preferably 1% by mass or more, more preferably 1.5% by mass or more, and still more preferably 2% by mass or more in the external preparation for skin, from the viewpoint of suppressing stickiness at the time of application to skin and obtaining a good touch. From the viewpoint of suppressing stickiness when applied to the skin and obtaining a good feel, and from the viewpoint of being less likely to whiten when applied to the skin, the skin external preparation is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. The specific range of the content of the component (d) in the external preparation for skin of the present invention is preferably 1% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass or less, still more preferably 1.5% by mass or more and 10% by mass or less, and still more preferably 2% by mass or more and 10% by mass or less.

In the external preparation for skin of the present invention, the mass ratio of the total amount of the components (a) to (c) to the component (d) [ { (a) + (b) + (c) }/(d) ] is preferably 0.1 or more, more preferably 0.2 or more, and still more preferably 0.5 or more, from the viewpoint of obtaining an excellent infrared ray shielding effect and from the viewpoint of being less likely to whiten and giving a natural color when the external preparation for skin is applied to the skin. From the viewpoint of suppressing stickiness when applied to the skin and obtaining a good feel, it is preferably 5 or less, more preferably 3 or less, more preferably 2 or less, and still more preferably 1.5 or less. A specific range of the mass ratio [ { (a) + (b) + (c) }/(d) ] is preferably 0.1 or more and 5 or less, more preferably 0.2 or more and 3 or less, more preferably 0.5 or more and 2 or less, and still more preferably 0.5 or more and 1.5 or less.

< ingredient (e): ultraviolet absorber

The external preparation for skin of the present invention preferably further contains an ultraviolet absorber as the component (e) from the viewpoint of imparting an ultraviolet ray protection effect in addition to an infrared ray protection effect.

As the component (e), an organic ultraviolet absorber is preferable, and an oil-soluble organic ultraviolet absorber or a water-soluble organic ultraviolet absorber can be used. The component (e) is preferably an oil-soluble organic ultraviolet absorber from the viewpoints of obtaining an ultraviolet protection effect, naturalness of appearance when applied to the skin, good makeup adhesion after application, and inhibition of stickiness. The term "oil-soluble" means water-insoluble, specifically, water-soluble at 1 w/w% or less.

In addition, from the viewpoint of obtaining the effects of the present invention, the component (e) is different from, for example, an inorganic ultraviolet absorber such as an ultraviolet absorber in which the surface of an inorganic filler is coated with an ultraviolet absorbing material.

As the oil-soluble organic ultraviolet absorber, an oil-soluble ultraviolet absorber among salicylic acid-based ultraviolet absorbers, cinnamic acid-based ultraviolet absorbers, benzoyl methane-based ultraviolet absorbers, and other organic ultraviolet absorbers can be used.

Examples of such may be: salicylic acid ultraviolet absorbers such as homomenthyl salicylate and octyl salicylate;

cinnamic acid ultraviolet absorbers such as 2-ethylhexyl p-methoxycinnamate (for example, "Uvinul MC 80" by BASF), glycerol mono-2-ethylhexanoate di-methoxycinnamate, methyl 2, 5-diisopropylcinnamate, methyl bis (trimethylsilyloxy) silanylisopentylglycol trimethoxycinnamate, and a mixture of isopropyl p-methoxycinnamate and diisopropyl cinnamate;

benzoylmethane ultraviolet absorbers such as 4-isopropyldibenzoylmethane and 4-tert-butyl-4' -methoxydibenzoylmethane (for example, "PARSOL 1789" manufactured by DSM Nutrition Japan);

octocrylene (Octocrylene, e.g. "PARSOL 340" from DSM Nutrition Japan), 2-ethylhexyl dimethoxybenzylideneimidazolenepropanoate (e.g. "Soft Shade DH" from Ajinomoto), 1- (3, 4-dimethoxyphenyl) -4, 4-dimethyl-1, 3-pentanedione, methomyl (cinoxate), methyl anthranilate, 3- (4-methylbenzylidene) camphor, octyltriazone, diethylaminohydroxybenzoyl hexyl benzoate (hexyl 2- (4-diethylamino-2-hydroxybenzoyl) benzoate, e.g. "Uvinul Aplus" from BASF), bisethylhexyloxyphenol methoxyphenyl triazine (2, 4-bis { [4- (2-ethylhexyloxy) -2-hydroxy ] phenyl } -6- (4-methoxyphenyl) 1,3, 5-triazine, for example "TINOSORB S" from BASF, methylenebisbenzotriazolyl tetramethylbutylphenol (for example "TINOSORB M" from BASF), 2,4, 6-tris [4- (2-ethylhexyloxycarbonyl) anilino ] -1,3, 5-triazine (hereinafter also referred to as "ethylhexyl triazone"; for example, "Uvinul T150" by BASF), and the like.

As the water-soluble organic ultraviolet absorber, salicylic acid-based ultraviolet absorbers, cinnamic acid-based ultraviolet absorbers, benzoyl methane-based ultraviolet absorbers, and other ultraviolet absorbers having a solubility in water of more than 1 w/w% in the organic ultraviolet absorber can be used, and examples thereof include triethanolamine salicylate and diethanolamine p-methoxyhydrogen cinnamate.

Among the above, from the viewpoint of the ultraviolet protection effect, the component (e) is preferably at least one member selected from the group consisting of 2-ethylhexyl p-methoxycinnamate, 4-tert-butyl-4' -methoxydibenzoylmethane, octocrylene, 2-ethylhexyl dimethoxybenzylidenedioxoimidazolidine propionate, hexyl diethylaminohydroxybenzoyl benzoate, bis-ethylhexyloxyphenol methoxyphenyl triazine, methylenebis-benzotriazolyl tetramethylbutylphenol, and 2,4, 6-tris [4- (2-ethylhexyloxycarbonyl) anilino ] -1,3, 5-triazine, more preferably at least one member selected from the group consisting of 2-ethylhexyl p-methoxycinnamate, hexyl diethylaminobenzoyl benzoate, bis-ethylhexyloxyphenol methoxyphenyl triazine, p-methoxycinnamate, bis-ethylhexyloxybenzoate, And 2,4, 6-three [4- (2-ethyl hexyl oxygen carbonyl) anilino ] -1,3, 5-three triazine. More preferably 1 or more selected from the group consisting of 2-ethylhexyl p-methoxycinnamate, hexyl diethylaminooxybenzoate, and bisethylhexyloxyphenol methoxyphenyl triazine.

When the component (e) is used in the external preparation for skin of the present invention, the content thereof in the external preparation for skin is preferably 0.2% by mass or more, more 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 imparting an excellent ultraviolet protection effect. From the viewpoint of obtaining an excellent infrared ray shielding effect and from the viewpoint of being less likely to whiten when the external preparation for skin is applied to the skin and obtaining a natural color tone, the content is preferably 30% by mass or less, more preferably 25% by mass or less, more preferably 20% by mass or less, and still more preferably 15% by mass or less. The specific range of the content of the component (e) in the external preparation for skin is preferably 0.2% by mass or more and 30% by mass or less, more preferably 1% by mass or more and 25% by mass or less, more preferably 3% by mass or more and 20% by mass or less, and still more preferably 5% by mass or more and 15% by mass or less.

In the external preparation for skin of the present invention, the mass ratio of the total amount of components (a) to (c) to component (e) [ { (a) + (b) + (c) }/(e) ] is preferably 0.1 or more, more preferably 0.2 or more, and still more preferably 0.3 or more, from the viewpoint of obtaining an excellent infrared ray shielding effect and from the viewpoint of being less likely to whiten and obtaining a natural color tone when the external preparation for skin is applied to the skin. From the viewpoint of imparting an excellent ultraviolet protection effect, the amount is preferably 5 or less, more preferably 3 or less, more preferably 1 or less, and still more preferably 0.5 or less. A specific range of the mass ratio [ { (a) + (b) + (c) }/(e) ] is preferably 0.1 or more and 5 or less, more preferably 0.1 or more and 3 or less, more preferably 0.2 or more and 1 or less, still more preferably 0.3 or more and 1 or less, and still more preferably 0.3 or more and 0.5 or less.

< ingredient (f): oil preparation >

The external preparation for skin of the present invention preferably further contains an oil agent as the component (f) from the viewpoint of improving the applicability to the skin by dispersing the components (a) to (c) and dispersing or dissolving other formulating components, and from the viewpoint of preparing an external preparation for skin of oil-in-water type or water-in-oil type. As the oil agent, any of the nonvolatile oil (f1) and the volatile oil (f2) other than the above-mentioned component (e) may be used, and these may be used in combination. When an oil-soluble ultraviolet absorber is used as the component (e) in the external preparation for skin of the present invention, the oil agent (f) preferably contains at least a nonvolatile oil (f1) from the viewpoint of dissolving it.

(nonvolatile oil (f1))

The external preparation for skin of the present invention preferably contains a nonvolatile oil (f1) as the oil agent (f). By non-volatile oil is meant an oil having an evaporation of less than 20% at 25 ℃ for 6 hours as determined by method (1) below.

Method (1): a filter paper having a diameter of 90mm was put into a glass petri dish having a diameter of 120mm, 1g of the sample was placed on the filter paper, and the sample was stored in a chamber (25 ℃) having 65% RH. Then, the residue of the sample after 6 hours was measured, and the evaporation amount was calculated.

The component (f1) is preferably in a liquid state at 25 ℃ under 1 atmosphere. More specifically, the viscosity of the component (f1) at 25 ℃ is preferably 500 mPas or less, more preferably 300 mPas or less, still more preferably 100 mPas or less, still more preferably 50 mPas or less, and preferably 5 mPas or more.

The viscosity was measured using a B-type viscometer "TVB-10" (manufactured by Toyobo industries Co., Ltd.) under conditions of rotor No.1, 25 ℃, 60rpm, and 1 minute.

Specific examples of the component (f1) include nonvolatile oils that are liquid at 25 ℃ other than the component (e), and examples thereof include ester oils, silicone oils, hydrocarbon oils, higher fatty acids, and higher alcohols.

Examples of the nonvolatile liquid ester oil include 1 or more kinds of alkyl benzoates selected from isononyl isononanoate, isotridecyl isononanoate, isopropyl myristate, isocetyl myristate, octyldodecyl myristate, isopropyl palmitate, ethylhexyl palmitate, 2-hexyldecyl palmitate, glyceryl tri-2-ethylhexanoate, di-2-ethylhexyl sebacate, diisopropyl sebacate, glyceryl tri (caprylic/capric) ester, diisostearyl malate, diethylene glycol didecanoate, neopentyl glycol di-2-ethylhexanoate, and alkyl benzoates (C12 to C15).

Among the above, from the viewpoint of obtaining a natural color tone when applied to the skin and from the viewpoint of suppressing stickiness, monoesters of fatty acids having 12 to 18 carbon atoms and branched alcohols having 2 to 22 carbon atoms, triesters of branched fatty acids having 6 to 18 carbon atoms and glycerin, diesters of dicarboxylic acids having 2 to 18 carbon atoms and branched alcohols having 2 to 18 carbon atoms, diesters of fatty acids having 6 to 18 carbon atoms and branched diols having 2 to 10 carbon atoms, alkyl benzoate (C12 to C15) esters (e.g., Finsolve TN, manufactured by Innospec Active Chemicals LLC), and the like are preferable, and specifically, isopropyl myristate, isocetyl myristate, octyldodecyl myristate, isopropyl palmitate, ethylhexyl palmitate, and the like are more preferable, 2-hexyldecyl palmitate, glyceryl tri-2-ethylhexanoate, diisopropyl sebacate, di-2-ethylhexyl sebacate, diisostearyl malate, neopentyl glycol di-2-ethylhexanoate, neopentyl glycol didecanate, and alkyl benzoate (C12-C15), more preferably 1 or more selected from isopropyl palmitate and alkyl benzoate (C12-C15).

The nonvolatile liquid silicone oil is preferably a methylpolysiloxane from the viewpoint of suppressing stickiness when applied to the skin, and more preferably a methylpolysiloxane having a viscosity of 20mPa · s or less at 25 ℃.

Examples of the non-volatile liquid hydrocarbon oil include light liquid isoparaffin such as liquid paraffin and hydrogenated polyisobutene, heavy liquid isoparaffin, liquid ceresin, squalane, pristane, squalene, and isohexadecane. Among these, from the viewpoint of suppressing stickiness when applied to the skin, 1 or more selected from light liquid isoparaffins and isohexadecane is preferable, and light liquid isoparaffins are more preferable.

Examples of the nonvolatile liquid higher fatty acid include fatty acids having 12 to 22 carbon atoms, and specific examples thereof include oleic acid, isostearic acid, linoleic acid, and linoleic acid (linolenic acid).

Examples of the nonvolatile liquid higher alcohol include alcohols having 12 to 28 carbon atoms, and specific examples thereof include oleyl alcohol, 2-decyltetradecyl alcohol, dodecyl alcohol, isostearyl alcohol, and octyldodecyl alcohol.

From the viewpoint of suppressing stickiness when applied to the skin, the component (f1) is preferably at least one selected from ester oils, silicone oils, and hydrocarbon oils, more preferably at least one selected from ester oils and hydrocarbon oils, and even more preferably at least one selected from alkyl (C12-15) benzoates, isopropyl palmitate, and light liquid isoparaffins, in the nonvolatile oil that is liquid at 25 ℃.

When the external preparation for skin of the present invention contains the component (f1), the application to the skin is improved by dispersing the components (a) to (c) and dispersing or dissolving the other formulating components; and an oil-in-water or water-in-oil type external preparation for skin, the content thereof is preferably 1% by mass or more, more preferably 4% by mass or more, and still more preferably 8% by mass or more. From the viewpoint of obtaining an excellent infrared ray shielding effect and from the viewpoint of suppressing stickiness when applied to the skin, the content is preferably 99% by mass or less, more preferably 90% by mass or less, more preferably 80% by mass or less, still more preferably 50% by mass or less, and still more preferably 30% by mass or less. The specific range of the content of the component (f1) in the external preparation for skin is preferably 1% by mass or more and 99% by mass or less, more preferably 4% by mass or more and 90% by mass or less, more preferably 8% by mass or more and 80% by mass or less, still more preferably 8% by mass or more and 50% by mass or less, and still more preferably 8% by mass or more and 30% by mass or less.

When the external preparation for skin of the present invention contains the component (f1), the mass ratio of the total amount of the components (a) to (c) to the component (f1) [ { (a) + (b) + (c) }/(f1) ] is preferably 0.01 or more, more preferably 0.05 or more, and still more preferably 0.1 or more, from the viewpoint of obtaining an excellent infrared ray shielding effect and from the viewpoint of being less likely to whiten and obtaining a natural color tone when the external preparation for skin is applied to the skin; from the viewpoint of dissolving the oil-soluble ultraviolet absorber, the viewpoint of improving the coating properties, and the viewpoint of preparing an oil-in-water or water-in-oil type external preparation for skin, it is preferably 10 or less, more preferably 5 or less, more preferably 3 or less, still more preferably 1 or less, and still more preferably 0.5 or less. The specific range of the mass ratio [ { (a) + (b) + (c) }/(f1) ] is preferably 0.01 or more and 10 or less, more preferably 0.01 or more and 5 or less, more preferably 0.05 or more and 3 or less, still more preferably 0.1 or more and 1 or less, and still more preferably 0.3 or more and 0.5 or less.

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

(volatile oil (f2))

The volatile oil used herein means an oil other than the ultraviolet absorber (e) and has an evaporation rate of 20% or more at 25 ℃ for 6 hours as measured by the following method (1).

The component (f2) is preferably a volatile silicone oil, and more preferably a silicone oil which is liquid and volatile at 25 ℃ in the linear organopolysiloxane and the cyclic organopolysiloxane.

Specific examples of the linear organopolysiloxane include octamethyltrisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane, and 1,1,1,3,5,5, 5-heptamethyl-3- [ (trimethylsilyl) oxy ] -trisiloxane.

Examples of the cyclic organopolysiloxane include 4-to 6-membered cyclic siloxanes having an alkyl group with 1 to 5 carbon atoms as a substituent, and specific examples include octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane.

Among the above, the component (f2) is preferably a cyclic organopolysiloxane, and more preferably decamethylcyclopentasiloxane, from the viewpoint of suppressing stickiness when applied to the skin.

Commercially available volatile silicone oils that can be used as component (f2) include, for example: "KF-96A-1 cs" (octamethyltrisiloxane), "KF-96L-1.5 cs" (decamethyltetrasiloxane), "KF-96L-2 cs" (dodecamethylpentasiloxane), "KF-995" (decamethylcyclopentasiloxane), "TMF-1.5" (1,1,1,3,5,5, 5-heptamethyl-3- [ (trimethylsilyl) oxy ] -trisiloxane), DOW TORAY CO manufactured by shin-Etsu chemical Co., Ltd, "DOWSIL SH200C Fluid1 cs" (octamethyltrisiloxane), "DOWSIL SH200C Fluid 1.5 cs" (decamethyltetrasiloxane), "DOWSIL SH200C Fluid 2 cs" (dodecamethylpentasiloxane), "DOWSIL SH245 Fluid" (decamethylcyclopentasiloxane), and "TSF 405" (decamethylcyclopentasiloxane) manufactured by Momentive Performance Materials, Inc., manufactured by LTD.

When the component (f2) is contained in the external preparation for skin of the present invention, the content thereof may be appropriately selected depending on the form of the external preparation for skin, and may be preferably 1% by mass or more, more preferably 5% by mass or more, and still more preferably 10% by mass or more. From the viewpoint of suppressing stickiness when applied to the skin, the content may be preferably 85% by mass or less, more preferably 80% by mass or less, and still more preferably 75% by mass or less. The specific range of the content of the component (f2) in the external preparation for skin is preferably 1% by mass or more and 85% by mass or less, more preferably 5% by mass or more and 80% by mass or less, and still more preferably 10% by mass or more and 75% by mass or less.

(aqueous Medium)

The external preparation for skin of the present invention may further contain an aqueous medium as necessary, from the viewpoint of dispersing or dissolving the components (a) to (c) and other formulating components, and from the viewpoint of preparing an oil-in-water or water-in-oil external preparation for skin. The aqueous medium is not particularly limited as long as the components (a) to (c) and other compounding ingredients can be dispersed or dissolved, and examples thereof include: water; monohydric alcohols having 4 or less carbon atoms such as ethanol, isopropanol, and butanol; low molecular weight diols and triols having 6 or less carbon atoms such as 1, 3-butanediol, glycerin, ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol. Among these, 1 or more selected from water and monohydric alcohols having 4 or less carbon atoms are preferable, and 1 or more selected from water and ethanol are more preferable.

When the aqueous medium is contained in the external preparation for skin, the content thereof may be appropriately selected depending on the form of the external preparation for skin, and is preferably 5% by mass or more, more preferably 8% by mass or more, and still more preferably 10% by mass or more. Further, it is preferably 99% by mass or less, more preferably 90% by mass or less, still more preferably 70% by mass or less, and still more preferably 50% by mass or less.

< other ingredients >

The skin preparation for external use of the present invention may contain, in addition to the above-mentioned components, other components such as a surfactant, an ultraviolet scattering agent, an antiperspirant, a perfume, a moisturizer, a tackifier, a bactericide, a pH adjuster, an antioxidant, a preservative, and the like, as required.

(method for producing skin preparation for external use)

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 according to the form of the external preparation for skin. For example, the components (a) to (c) and all other components are blended and uniformly mixed by a homogenizer, a disperser, or the like. In the case of blending the aqueous medium, a method of blending all the components other than the aqueous medium, uniformly mixing the components by a disperser or the like, blending the aqueous medium, and further stirring and mixing the blended aqueous medium by a homogenizer or the like may be used.

[ method of protecting skin from infrared rays ]

The present invention also provides a method for protecting skin from infrared radiation, which comprises applying the external preparation for skin of the present invention to the skin. The method of protecting the skin of the present invention is not particularly limited as long as it includes the step of applying the external skin preparation of the present invention to the skin.

In the protection method of the present invention, the infrared protection rate at a wavelength of 1500nm is preferably 10% or more, more preferably 12% or more, and still more preferably 15% or more. When the infrared ray shielding rate at a wavelength of 1500nm is in the above range, the heat-insulating feeling of the skin is good. The infrared ray shielding rate (%) can be a value represented by 100-X (%) assuming that X (%) is an infrared ray transmittance measured by a spectrophotometer, and can be measured specifically by the methods described in examples.

When the external preparation for skin of the present invention is applied to the skin, infrared rays can be effectively prevented.

The present invention further discloses the following embodiments with respect to the above embodiments.

<1> an external preparation for skin, which is prepared by blending the following components (a) to (c),

(a) a plate-like metal oxide having a thickness of 100nm to 120 nm;

(b) a plate-like metal oxide having a thickness of 125nm to 145 nm; and

<2> the external preparation for skin as stated in <1>, wherein the plate-like metal oxide is preferably at least 1 selected from the group consisting of plate-like titanium oxide and plate-like zinc oxide, and more preferably plate-like titanium oxide.

<3> the external preparation for skin as stated in <1> or <2>, wherein the plate-like metal oxide is preferably obtained by surface-treating 1 or more selected from the group consisting of silicone and alkylalkoxysilane, more preferably 1 or more selected from the group consisting of methylpolysiloxane, dimethylpolysiloxane, methylhydropolysiloxane, (alkyl acrylate/polydimethylsiloxane) copolymer, and octyltriethoxysilane.

<4> the external preparation for skin as stated in any one of <1> to <3>, wherein the thickness of the component (a) is preferably 105nm or more and 115nm or less;

the thickness of the component (b) is preferably 130nm to 140 nm;

the thickness of the component (c) is preferably 185nm to 195 nm.

<5> the external preparation for skin according to any one of <1> to <4>, wherein the average particle diameter of the components (a) to (c) is preferably 1 μm or more and 20 μm or less, more preferably 2 μm or more and 15 μm or less, more preferably 2 μm or more and 12 μm or less, still more preferably 3 μm or more and 10 μm or less, and still more preferably 5 μm or more and 10 μm or less.

<6> the external preparation for skin as stated in any one of <1> to <5>, wherein the aspect ratio of the components (a) to (c) is preferably 10 or more and 200 or less, more preferably 10 or more and 150 or less, more preferably 10 or more and 100 or less, still more preferably 20 or more and 100 or less, still more preferably 30 or more and 100 or less, and still more preferably 35 or more and 90 or less.

<7> the external preparation for skin according to any one of <1> to <6>, wherein the blending ratio of the component (a), the component (b) and the component (c) satisfies the following condition 1, more preferably satisfies the following condition 2, with respect to 100 mass% of the total blending amount of the components (a) to (c);

condition 1: in a three-phase diagram showing the mass% of the component (a), the component (b) and the component (c) in 100 mass% relative to the total amount of the components (a) to (c), the blending ratio of each component is within a composition region surrounded by 6 composition points shown below,

<8> the external preparation for skin as stated in any one of <1> to <7>, wherein the total amount of the components (a) to (c) in the external preparation for skin is preferably 1% by mass or more and 35% by mass or less, more preferably 1% by mass or more and 25% by mass or less, more preferably 1% by mass or more and 20% by mass or less, still more preferably 1% by mass or more and 15% by mass or less, still more preferably 1.5% by mass or more and 10% by mass or less, and still more preferably 2% by mass or more and 10% by mass or less.

<9> the external preparation for skin as stated in any one of <1> to <8>, which further comprises a touch feeling improver as the component (d).

<10> the external preparation for skin as <9>, wherein the component (d) is preferably spherical inorganic particles, more preferably spherical metal oxide particles, more preferably 1 or more selected from spherical titanium oxide particles and spherical zinc oxide particles, and still more preferably spherical titanium oxide particles.

<11> the external preparation for skin as <9> or <10>, wherein the average particle diameter of the particles used as the component (d) is preferably 0.1 μm or more and 10 μm or less, more preferably 0.2 μm or more and 5 μm or less, and still more preferably 0.5 μm or more and 2 μm or less.

<12> the external preparation for skin as stated in any one of <9> to <11>, wherein the content of the component (d) is preferably 1% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass or less, still more preferably 1.5% by mass or more and 10% by mass or less, and still more preferably 2% by mass or more and 10% by mass or less.

<13> the external preparation for skin as stated in any one of <9> to <12>, wherein the mass ratio of the total amount of components (a) to (c) to component (d) [ { (a) + (b) + (c) }/(d) ] is preferably 0.1 or more and 5 or less, more preferably 0.2 or more and 3 or less, more preferably 0.5 or more and 2 or less, and still more preferably 0.5 or more and 1.5 or less.

<14> the external preparation for skin as stated in any one of <1> to <13>, which further comprises an ultraviolet absorber as the component (e).

<15> the external preparation for skin as stated in <14>, wherein the component (e) is preferably an oil-soluble organic ultraviolet absorber, more preferably 1 or more selected from the group consisting of 2-ethylhexyl p-methoxycinnamate, 4-tert-butyl-4' -methoxydibenzoylmethane, octocrylene, 2-ethylhexyl dimethoxybenzylidenedioxoimidazolidenepropionate, hexyl diethylaminohydroxybenzoylbenzoate, bisethylhexyloxyphenol methoxyphenyl triazine, methylenebisbenzotriazolyl tetramethylbutylphenol, and 2,4, 6-tris [4- (2-ethylhexyloxycarbonyl) anilino ] -1,3, 5-triazine, and more preferably 2-ethylhexyl p-methoxycinnamate, hexyl diethylaminohydroxybenzoylbenzoate, hexyl diethylamino-dioxobenzoate, Bis-ethylhexyloxyphenol methoxyphenyl triazine, and 2,4, 6-tris [4- (2-ethylhexyloxycarbonyl) anilino ] -1,3, 5-triazine, and more preferably 1 or more selected from the group consisting of 2-ethylhexyl p-methoxycinnamate, diethylamino hydroxybenzoyl hexyl benzoate, and bis-ethylhexyloxyphenol methoxyphenyl triazine.

<16> the external preparation for skin as stated in <14> or <15>, wherein the content of the component (e) is preferably 0.2% by mass or more and 30% by mass or less, more preferably 1% by mass or more and 25% by mass or less, more preferably 3% by mass or more and 20% by mass or less, and still more preferably 5% by mass or more and 15% by mass or less.

<17> the external preparation for skin as stated in any one of <14> to <16>, wherein the mass ratio of the total amount of the components (a) to (c) to the component (e) [ { (a) + (b) + (c) }/(e) ] is preferably 0.1 or more and 5 or less, more preferably 0.1 or more and 3 or less, more preferably 0.2 or more and 1 or less, still more preferably 0.3 or more and 1 or less, and still more preferably 0.3 or more and 0.5 or less.

<18> the external preparation for skin as stated in any one of <1> to <17>, which further comprises an oil agent as the component (f); preferably containing a non-volatile oil (f 1).

<19> the external preparation for skin as stated in <18>, wherein the component (f1) is at least 1 selected from the group consisting of ester oils, silicone oils, hydrocarbon oils, higher fatty acids and higher alcohols; preferably 1 or more selected from ester oils, silicone oils, and hydrocarbon oils, more preferably 1 or more selected from ester oils and hydrocarbon oils, and still more preferably 1 or more selected from alkyl (C12-15) benzoates, isopropyl palmitate, and light liquid isoparaffins.

<20> the external preparation for skin as <18> or <19>, wherein the content of the component (f1) is preferably 1% by mass or more and 99% by mass or less, more preferably 4% by mass or more and 90% by mass or less, more preferably 8% by mass or more and 80% by mass or less, still more preferably 8% by mass or more and 50% by mass or less, and still more preferably 8% by mass or more and 30% by mass or less.

<21> the external preparation for skin as stated in any one of <18> to <20>, wherein the mass ratio of the total amount of the components (a) to (c) to the component (f1) [ { (a) + (b) + (c) }/(f1) ] is preferably 0.01 or more and 10 or less, more preferably 0.01 or more and 5 or less, more preferably 0.05 or more and 3 or less, still more preferably 0.1 or more and 1 or less, and still more preferably 0.3 or more and 0.5 or less.

<22> the external preparation for skin as stated in any one of <18> to <21>, wherein the mass ratio [ (e)/(f1) ] is preferably 0.01 or more and 10 or less, more preferably 0.02 or more and 5 or less, more preferably 0.05 or more and 3 or less, and still more preferably 0.1 or more and 3 or less.

<23> the external preparation for skin as stated in any one of <18> to <22>, which comprises a volatile oil (f2) as the component (f); the silicone oil is preferably a volatile silicone oil, more preferably a volatile silicone oil that is liquid and volatile at 25 ℃ and that contains a linear organopolysiloxane and a cyclic organopolysiloxane, even more preferably a cyclic siloxane having 4 to 6-membered rings with an alkyl group having 1 to 5 carbon atoms as a substituent, and even more preferably decamethylcyclopentasiloxane.

<24> the external preparation for skin as <23>, wherein the content of the component (f2) is preferably 1% by mass or more and 85% by mass or less, more preferably 5% by mass or more and 80% by mass or less, and still more preferably 10% by mass or more and 75% by mass or less.

<25> an external preparation for skin, which is obtained by blending the following components (a) to (c),

(a) plate-like titanium oxide having a thickness of 100nm to 120 nm;

(b) a plate-like titanium oxide having a thickness of 125nm to 145 nm; and

(c) a plate-like titanium oxide having a thickness of 180nm or more and 200nm or less,

the average particle diameters of the components (a) to (c) are not less than 3 μm and not more than 10 μm,

the blending amount of the component (a) is 5 to 70 mass%, the blending amount of the component (b) is 15 to 75 mass%, the blending amount of the component (c) is 5 to 70 mass% with respect to 100 mass% of the total blending amount of the components (a) to (c),

the total amount of components (a) to (c) in the external preparation for skin is 2 to 10 mass%.

<26> an external preparation for skin, which is obtained by blending the following components (a) to (c),

(a) plate-like titanium oxide having a thickness of 100nm to 120 nm;

(b) plate-like titanium oxide having a thickness of 125nm to 145 nm; and

the blending ratio of the component (a), the component (b) and the component (c) satisfies the following condition 1 with respect to 100 mass% of the total blending amount of the components (a) to (c),

the total amount of components (a) to (c) in the external preparation for skin is 2 to 10 mass%,

(a,b,c)＝(70,15,15)、(28,26,46)、(5,40,55)、(5,67,28)、(20,68,12)、(57,33,10)。

<27> an external preparation for skin, which is obtained by blending the following components (a) to (c),

(a) plate-like titanium oxide having a thickness of 100nm to 120 nm;

(b) plate-like titanium oxide having a thickness of 125nm to 145 nm; and

the blending ratio of the component (a), the component (b) and the component (c) satisfies the following condition 2 with respect to 100 mass% of the total blending amount of the components (a) to (c),

the total amount of components (a) to (c) in the external preparation for skin is 2 to 10% by mass,

<28> the external preparation for skin as stated in any one of <25> to <27>, which further contains, as the component (d), 2 mass% or more and 10 mass% or less of 1 or more of a feel improver selected from spherical titanium oxide particles and spherical zinc oxide particles;

the component (e) contains an oil-soluble organic ultraviolet absorber in an amount of 5 to 15 mass%;

the component (f) contains 8 to 50 mass% of at least 1 type of nonvolatile oil (f1) selected from ester oils and hydrocarbon oils.

<29> the external preparation for skin according to any one of <1> to <28>, wherein the dosage form is in the form of liquid, gel or cream.

<30> the external preparation for skin according to any one of <1> to <29>, which is a skin cosmetic, preferably a sunscreen cosmetic, a tanning agent or a makeup base cosmetic.

<31> a method for protecting skin from infrared rays, wherein the external preparation for skin of any one of <1> to <30> is applied to skin.

<32> the method of <31>, wherein the infrared shielding rate at a wavelength of 1500nm is preferably 10% or more, more preferably 12% or more, and still more preferably 15% or more.

[ examples ]

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

(measurement of thickness)

The thickness of the plate-like titanium oxide used as the components (a) to (c) was measured by using a scanning electron microscope ("VE-9800" manufactured by KEYENCE CORPORATION) for the components (a) to (c) at an acceleration voltage: 10keV, observation magnification: the thickness of 50 particles in the observed image was measured under a condition of 10,000 times, and the average value of each particle was calculated.

(measurement of average particle diameter and aspect ratio)

The average particle diameters of the plate-like titanium oxide used as the components (a) to (c) and the spherical titanium oxide used as the component (D) were determined by using a laser diffraction/scattering particle size distribution measuring apparatus ("LA 920" manufactured by horiba ltd.) and taking the value of the median diameter (D50) measured by the particle diameter reference volume with the relative refractive index of the aqueous dispersion of 2.0 as the average particle diameter.

The aspect ratio of the plate-like titanium oxide used as components (a) to (c) was calculated from (average particle diameter/thickness).

[ evaluation (1): infrared ray protection factor, color tone when applied to skin, and comprehensive evaluation

(Infrared ray defense rate)

28.5mg of the external preparation for skin of each example was applied to a 5 cm. times.5 cm polymethyl methacrylate (PMMA) substrate ("HD 6" manufactured by HelioScreen corporation), and dried for 15 minutes to obtain a sample for measurement. Further, glycerin was similarly applied to a PMMA substrate, and dried for 15 minutes to serve as a control sample. The transmittance at a wavelength of 1500nm was measured in an integrating sphere mode using a spectrophotometer ("UV-3600" manufactured by Shimadzu corporation) for each of the measurement sample and the control sample. The transmittance X (%) is the value obtained by dividing the transmittance of the measurement sample by the transmittance of the control sample, and the infrared ray shielding rate is 100-X (%). The larger the value, the higher the infrared ray shielding effect.

(color tone when applied to skin)

Each example of the external preparation for skin was prepared at 2mg/cm²The coating was applied to the forearm 2 of 4 subjects, and the hue immediately after the coating was evaluated as 1 point and very good as 5 points, and evaluation was made in 10 steps in 0.5 point units according to the following evaluation criteria. Evaluation was performed by 2 professional sensory evaluators, and the average score (rounded off second after decimal point) was used as an evaluation score.

< evaluation Standard >

1: very poor

2: difference (D)

3: medium and high grade

4: good taste

5: is very good

(comprehensive evaluation)

Among the evaluation results shown in table 1, a sample having an evaluation score of 3.6 or more in color tone when applied to the skin was rated a, a sample having a score of 3.0 or more and 3.5 or less was rated B, a sample having a score of 2.5 or more and 2.9 or less was rated C, and a sample having a score of 2.4 or less was rated D. Further, the results of raising the infrared ray shielding rate of the sample of 15% or more by 1 rank and lowering the infrared ray shielding rate of the sample of less than 15% by 1 rank are shown in table 1 as a comprehensive evaluation. The total evaluation was carried out in 6 stages of A +, A, B, C, D and D-.

[ evaluation (2): color tone and transparency ]

The skin external preparations of the respective examples were evaluated by the following methods when applied to the skin: the hue is shifted to red, blue or green; and an unnatural appearance such as no transparency and a white state is not felt; and whether a natural hue is achieved.

2mg/cm of each of 4 forearm parts with different skin colors²When the skin external preparation was applied, the color tone and the transparency were visually observed, and evaluation was performed in 10 steps on a scale unit of 0.5 on the basis of the following evaluation standards. Evaluation was performed by 2 professional sensory evaluators, and the average score (rounded off second after decimal point) was used as an evaluation score.

Regarding 4 items with reddish, bluish, greenish and transparent feelings, the item with no evaluation score less than 2.0 and with 2 or more evaluation scores of 3.0 or more was regarded as passed, and the others as failed.

< evaluation criteria >

(with red)

5: less red sensation

4: slightly reddish with slight sensation

3: medium and high grade

2: slightly reddish with strong sensation

1: strong reddish sensation

(with blue)

5: less bluish sensation

4: slightly bluish sensation

3: medium and high grade

2: slightly stronger bluish sensation

1: strong bluish feeling

(with green)

5: less greenish feeling

4: slightly green and slight

3: medium and high grade

2: slightly greenish

1: strong greenness

(transparency feeling)

5: has transparent feeling

4: slightly transparent feeling

3: medium and high grade

2: slightly without transparent feeling

1: no sense of transparency

Production example 1 (production of plate-shaped titanium oxide 1)

Untreated titanium oxide plate (CQV "Featheleve PT-7401K", thickness 112nm, aspect ratio 126, average particle diameter 14.1 μm) was pulverized using an impact classifier built-in pulverizer ("ACM-10", Hosokawa Micron Corporation) and then coated with an alkyl acrylate/polydimethylsiloxane copolymer to obtain titanium oxide plate 1 having a thickness 112nm, an aspect ratio 80, and an average particle diameter 9.0 μm.

Production example 2 (production of plate-shaped titanium oxide 2)

The plate-like titanium oxide 2 having a thickness of 134nm, an aspect ratio of 64 and an average particle diameter of 8.6 μm was obtained by treating the plate-like titanium oxide in the same manner as in production example 1 except that "Featheleve PT-7401K" manufactured by CQV was used in place of "Featheleve PT-7401K" manufactured by CQV.

Production example 3 (production of plate-shaped titanium oxide 3)

Plate-like titanium oxide 3 having a thickness of 191nm, an aspect ratio of 44 and an average particle diameter of 8.5 μm was obtained by treating the untreated plate-like titanium oxide in the same manner as in production example 1, except that "Featheleve PT-7901K" manufactured by CQV was used in place of "Featheleve PT-7401K" manufactured by CQV "(thickness of 191nm, aspect ratio of 58 and average particle diameter of 11.1 μm).

Examples 1 to 12 and comparative examples 1 to 8 (production and evaluation of skin external preparations)

The ingredients shown in table 1 were mixed and uniformly mixed by using a homogenizer to prepare an external preparation for skin having the composition shown in table 1. The obtained skin external preparation was evaluated by the above-described method. The results are shown in Table 1. The amounts of the effective components (mass%) in table 1 were the amounts of the respective components.

The formulation of table 1 is as follows.

﹡ 1: production of plate-like titanium oxide 1 obtained in example 1;

﹡ 2: production of plate-like titanium oxide 2 obtained in example 2;

﹡ 3: the plate-like titanium oxide 3 obtained in production example 3;

﹡ 4: "ST-750 EC" manufactured by Titan Kogyo, Ltd., spherical titanium oxide having an average particle diameter of 1000nm and an aspect ratio of 1.0;

﹡ 5: "Uvinal MC 80" manufactured by BASF corporation, 2-ethylhexyl p-methoxycinnamate;

﹡ 6: EXCEPARL IPP manufactured by Kao corporation, isopropyl palmitate;

﹡ 7: TSF405 manufactured by Momentive Performance Materials, decamethylcyclopentasiloxane.

From table 1, the external preparations for skin of examples 1 to 12 can achieve both the infrared ray shielding effect and the natural color tone when applied to the skin. Among them, examples 1,3, 4,6, 8 and 9 in which the blending ratios of the components (a) to (c) satisfy the above condition 1 were evaluated as A or more in general and are excellent; examples 4 and 6 satisfying the above condition 2 were evaluated as A + in combination, and were more preferable.

On the other hand, the external preparations for skin of comparative examples 1 to 8 did not exhibit sufficient effects in at least one of the infrared ray shielding effect and the natural color tone when applied to the skin.

The markers a +, A, B, C, D, and D + shown in the three-phase diagram of fig. 1 indicate the above-described overall evaluation of the components (a) to (c) corresponding to the external preparations for skin of examples 1 to 12 and comparative examples 1 to 8.

(availability in industry)

The external preparation for skin of the present invention has an excellent infrared ray shielding effect, is unlikely to be reddish or bluish when applied to the skin, and can provide a natural color tone that is compatible with the skin color, and is useful, for example, as a skin cosmetic.

Claims

1. A skin external preparation comprises, as active ingredients,

the skin external preparation is prepared by blending the following components (a) to (c),

(a) a plate-like metal oxide having a thickness of 100nm to 120 nm;

(b) a plate-like metal oxide having a thickness of 125nm to 145 nm; and

2. The external preparation for skin according to claim 1,

the plate-like metal oxide is plate-like titanium oxide.

3. The external preparation for skin according to claim 1 or 2, wherein,

the average particle diameters of the components (a) to (c) are 1 to 20 μm.

4. The external preparation for skin as claimed in any one of claims 1 to 3,

the total amount of components (a) to (c) in the external preparation for skin is 1 to 35% by mass.

5. The external preparation for skin as claimed in any one of claims 1 to 4,

further contains a touch feeling improver as the component (d).

6. The external preparation for skin as claimed in any one of claims 1 to 5,

further contains an ultraviolet absorber as the component (e).

7. The external preparation for skin as claimed in any one of claims 1 to 6, wherein,

further contains an oil agent as the component (f).

8. The external preparation for skin as claimed in any one of claims 1 to 7,

the skin external preparation is skin cosmetic.

9. A method for protecting skin from infrared rays, wherein,

the external preparation for skin as claimed in any one of claims 1 to 8 is applied to the skin.