JP7645654B2 - Oil-in-water emulsion cosmetics - Google Patents

Description

The present invention relates to an oil-in-water emulsion cosmetic, in particular an oil-in-water emulsion cosmetic for infrared protection.

Conventionally, UV protective cosmetics have been known from the perspective of protecting the skin against sunlight.

For example, Patent Document 1 discloses an oil-in-water emulsion cosmetic that contains an ultraviolet absorbing agent and an ultraviolet scattering agent, has high ultraviolet protection capability (SPF), and has a uniquely refreshing feel when used. The cosmetic contains (A) 0.05 to 1% by mass of hydrophobically modified alkyl cellulose; (B) 5 to 40% by mass of oil; (C) 2.5 to 30% by mass of an ultraviolet scattering agent having a hydrophobic surface; and (D) an aqueous phase thickener with low salt resistance, and the ultraviolet scattering agent (C) is dispersed in the oil phase.

On the other hand, in recent years, health consciousness has increased, and there is a demand for cosmetics that can reduce the heat of sunlight and prevent photoaging of the skin by blocking not only ultraviolet rays (wavelength: about 290 to about 400 nm) but also infrared rays (wavelength: about 750 nm to about 1 mm).

For example, Patent Document 2 discloses a heat-shielding cosmetic that has an improved infrared heat-shielding effect while still retaining an ultraviolet ray blocking effect, and is characterized by the fact that titanium oxide (A) having an average particle size of 5 to 100 nm and titanium oxide (B) having an average particle size of 300 to 3000 nm are blended in a ratio of (A):(B) = 1:9 to 9:1 (weight ratio).

JP 2015-120682 A JP 2013-194041 A

However, for example, the heat-shielding cosmetic composition disclosed in Patent Document 2 contains a large amount of nonionic surfactant, which makes it difficult to achieve a fresh feel when used.

The present invention aims to improve the above situation, and its purpose is to provide a cosmetic product that has excellent infrared protection effects and a unique, refreshing feel when used.

The present invention, which achieves the above objective, is as follows:

<Aspect 1>
Contains the following components (a) to (d):
(a) metal oxide particles having an average particle size of 500 to 1,500 nm and having a hydrophobic surface;
(b) hydrophobically modified alkyl cellulose;
(c) an aqueous phase thickener; and (d) an oil.
the metal oxide particles are dispersed in the oil, and the content of a nonionic surfactant having an HLB value of 10 or more is less than 1.0 mass%.
Oil-in-water emulsion cosmetic.
<Aspect 2>
The cosmetic preparation according to Aspect 1, further comprising (e) polyhydroxystearic acid.
Aspect 3
The content of the metal oxide particles is 1.0% by mass or more and 30.0% by mass or less,
The content of the hydrophobically modified alkyl cellulose is 0.05% by mass or more and 1.0% by mass or less,
The content of the aqueous phase thickener is 0.05% by mass or more and 3.0% by mass or less, and the content of the oil content is 5.0% by mass or more and 40.0% by mass or less.
A cosmetic preparation according to aspect 1 or 2.
<Aspect 4>
A cosmetic preparation according to any one of Aspects 1 to 3, wherein the metal oxide particles are titanium oxide.
<Aspect 5>
The cosmetic preparation according to any one of Aspects 1 to 4, wherein the hydrophobically modified alkyl cellulose is hydrophobically modified hydroxypropyl methyl cellulose.
<Aspect 6>
A cosmetic preparation according to any one of Aspects 1 to 5, wherein the aqueous phase thickener comprises a vinyl polymer or an acrylic polymer.
Aspect 7
A cosmetic preparation according to any one of Aspects 1 to 6, wherein 55% by mass or more of the oil component is a polar oil.
<Aspect 8>
The cosmetic preparation according to any one of Aspects 1 to 7, further comprising (f) an ionic surfactant.
<Aspect 9>
(g) The cosmetic preparation according to any one of Aspects 1 to 8, further comprising a water-soluble polyether-modified silicone wax.
Aspect 10
The cosmetic preparation according to any one of Aspects 1 to 9, which is an infrared protective cosmetic preparation.

The present invention makes it possible to provide a cosmetic product that has excellent infrared protection effects and a unique, refreshing feel when used.

In the present invention, the term "unique, fresh feel when used" means that when the cosmetic is applied to the skin with the fingers or the like, the viscosity of the cosmetic drops suddenly and the cosmetic crumbles, and at the same time, the cosmetic gives a very fresh feel as it spreads over the skin.

The following describes in detail the embodiments of the present invention. Note that the present invention is not limited to the following embodiments, and can be modified in various ways within the scope of the invention.

<Oil-in-water emulsion cosmetics>
The oil-in-water emulsion cosmetic of the present invention (hereinafter, also simply referred to as "the cosmetic of the present invention") is
Contains the following components (a) to (d):
(a) metal oxide particles having an average particle size of 500 to 1,500 nm and having a hydrophobic surface;
(b) hydrophobically modified alkyl cellulose;
(c) an aqueous phase thickener; and (d) an oil.
The metal oxide particles are dispersed in an oil component, and the content of a nonionic surfactant having an HLB value of 10 or more is less than 1.0 mass%.

The cosmetic product of the present invention exhibits the effects of the present invention by containing specific components and by limiting the content of nonionic surfactants with an HLB value of 10 or more to less than 1.0% by mass, i.e., by providing excellent infrared protection and a unique, refreshing feel when used.

The cosmetic of the above-mentioned Patent Document 1 is intended mainly to block ultraviolet rays, and uses an ultraviolet scattering agent with a relatively small average particle size. For this reason, Patent Document 1 discloses that, instead of using a nonionic surfactant with a strong emulsifying effect, a hydrophobically modified alkyl cellulose with a relatively weak emulsifying effect is used to emulsify an oil containing an ultraviolet scattering agent with a relatively small average particle size, thereby obtaining an oil-in-water emulsion cosmetic in which a hydrophobic powder is dispersed in the internal oil phase.

On the other hand, it is difficult to emulsify oil containing metal oxide particles with a relatively large average particle size, and it is generally known to incorporate a large amount of a surfactant with a relatively strong emulsifying effect. For example, Patent Document 2 discloses the use of a large amount of a nonionic surfactant with a content of 1% by mass or more as an emulsifier to obtain an oil-in-water emulsion cosmetic in which a hydrophobic powder is dispersed in the internal oil phase.

On the other hand, the inventors of the present invention have not been limited by the conventional stereotypes mentioned above, and through their intensive research, have succeeded in obtaining an oil-in-water emulsion cosmetic in which a hydrophobic powder is dispersed in the internal oil phase by using a hydrophobically modified alkyl cellulose with a suitable emulsifying power, even in a system of "oil containing metal oxide particles with a relatively large average particle size," which was previously considered difficult to emulsify, and have thus arrived at the present invention.

Without being limited to theory, this is because when a surfactant with strong emulsifying power (i.e., a nonionic surfactant with an HLB value of 10 or more) is used, a stable interface film can be formed, but the size of the emulsified particles becomes relatively small. Therefore, it is thought that metal oxide particles with a relatively large average particle size become relatively close to the size of the emulsified particles and are easily detached from the emulsified particles (oil droplets). In contrast, in the present invention, by using a surfactant with a relatively weak emulsifying power such as hydrophobically modified alkyl cellulose, the emulsified particles become relatively large. Therefore, in this case, it is thought that metal oxide particles with a relatively large average particle size are less likely to detach from the emulsified particles.

In this way, by limiting the content of nonionic surfactants with an HLB value of 10 or more to less than 1.0 mass%, the present invention not only makes it possible to obtain an oil-in-water emulsion cosmetic in which a hydrophobic powder is dispersed in a stable internal oil phase without making the emulsion particle size smaller than desired, but also suppresses the sticky feel that results from a large amount of nonionic surfactant, resulting in a uniquely fresh feel when used.

In addition, in the cosmetic composition of the present invention, the content of the nonionic surfactant having an HLB value of 10 or more may be 0.9% by mass or less, 0.8% by mass or less, 0.7% by mass or less, 0.6% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, 0.2% by mass or less, 0.1% by mass or less, or 0% by mass.

(a) Metal Oxide Particles
The metal oxide particles contained in the cosmetic of the present invention (hereinafter also simply referred to as "metal oxide particles of the present invention") have an average particle size of 500 to 1500 nm and are metal oxide particles that have been surface-treated to be hydrophobic.

The metal oxide particles of the present invention have an average particle size of 500 to 1,500 nm, and therefore have the function of blocking infrared rays, particularly near-infrared rays.

In the present invention, "average particle size" refers to the average particle size of primary particles.

In addition, in the present invention, the average particle size can be calculated as the diameter of a circle equivalent to the projected area of the primary particles observed by SEM or TEM.

The metal oxide particles of the present invention are surface-hydrophobized. The hydrophobization may be performed using a known surface treatment agent that provides hydrophobization, and examples of such treatment include fluorine compound treatment, silicone treatment, silicone resin treatment, pendant treatment, silane coupling agent treatment, titanium coupling agent treatment, oil treatment, N-acylated lysine treatment, polyacrylic acid treatment, isostearic acid treatment, metal soap treatment, amino acid treatment, inorganic compound treatment, plasma treatment, mechanochemical treatment, silane compound treatment, and silazane compound treatment. Among these treatments, treatment with silicone or silicone resin, treatment with silane compound or silazane compound, and isostearic acid treatment are preferred from the viewpoint of dispersion stability, etc.

The metal oxide particles of the present invention may be surface-hydrophobically treated titanium oxide, surface-hydrophobically treated zinc oxide, surface-hydrophobically treated cerium oxide, or a mixture thereof, but from the viewpoint of improving the shielding effect in the infrared region, surface-hydrophobically treated titanium oxide is preferred.

The shape of the metal oxide particles of the present invention is not particularly limited, and examples include spherical, plate-like, rod-like, spindle-like, needle-like, and irregular shapes.

In addition, commercially available metal oxide particles may be used as the metal oxide particles of the present invention.

In addition, the metal oxide particles of the present invention may be commercially available products in which the metal oxide particles are dispersed with a dispersant such as polyhydroxystearic acid.

In the cosmetic of the present invention, the content of the metal oxide particles is not particularly limited, and may be, for example, 1.0% by mass or more, 1.5% by mass or more, 2.0% by mass or more, 2.5% by mass or more, 3.0% by mass or more, 3.5% by mass or more, 4.0% by mass or more, 4.5% by mass or more, 5.0% by mass or more, 5.5% by mass or more, 6.0% by mass or more, 6.5% by mass or more, 7.0% by mass or more, 7.5% by mass or more, 8.0% by mass or more, 8.5% by mass or more, 9.0% by mass or more, 9.5% by mass or more, or 10.0% by mass or more, or may be 30.0% by mass or less, 20.0% by mass or less, or 10.0% by mass or less. Note that, when the metal oxide particles are in a state of being dispersed in a dispersant such as polyhydroxystearic acid, the content of the metal oxide particles referred to here refers to the content of the solid content in the cosmetic of the present invention.

(b) Hydrophobically Modified Alkyl Cellulose
The hydrophobically modified alkyl cellulose contained in the cosmetic composition of the present invention does not belong to the category of "nonionic surfactants having an HLB value of 10 or more" and is generally classified as a "polymeric surfactant."

In the present invention, hydrophobically modified alkyl cellulose refers to alkyl cellulose that has been hydrophobically modified with an alkyl group having 14 to 22 carbon atoms. This hydrophobically modified alkyl cellulose is a compound in which a long-chain alkyl group, which is a hydrophobic group, has been introduced into a water-soluble cellulose ether derivative, and is represented by the following general formula (I).

［式中、Ｒは、同一でも異なってもよく、水素原子、炭素原子数が１～４のアルキル基、基－［ＣＨ_２ＣＨ（ＣＨ_３）Ｏ］_ｍ－Ｈ（式中、ｍは、１～５、好適には１～３の整数である）、基－ＣＨ_２ＣＨ_２ＯＨ、及び、基－ＣＨ_２ＣＨ（ＯＨ）ＣＨ_２ＯＲ’（式中、Ｒ’は、炭素原子数が１４～２２のアルキル基である）から選ばれる１種以上の基であるが、基－ＣＨ_２ＣＨ（ＯＨ）ＣＨ_２ＯＲ’を必ず含むものとする。また、Ａは、基－（ＣＨ_２）_ｑ－（ｑは、１～３の整数であり、好適には１である）であり、ｎは、１００～１００００、好適には５００～５０００の整数である。］

[wherein, R may be the same or different and is one or more groups selected from a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a -[CH ₂ CH(CH ₃ )O] _m -H group (wherein m is an integer of 1 to 5, preferably 1 to 3), a -CH ₂ CH ₂ OH group, and a -CH ₂ CH(OH)CH ₂ OR' group (wherein R' is an alkyl group having 14 to 22 carbon atoms), but the -CH ₂ CH(OH)CH ₂ OR' group is always included. In addition, A is a -(CH ₂ ) _q - group (wherein q is an integer of 1 to 3, preferably 1), and n is an integer of 100 to 10,000, preferably 500 to 5,000.]

The method for producing the hydrophobically modified alkyl cellulose of formula (I) generally involves contacting a base water-soluble cellulose ether derivative, specifically methyl cellulose (R is a hydrogen atom or a methyl group), ethyl cellulose (R is a hydrogen atom or an ethyl group), propyl cellulose (R is a hydrogen atom or a propyl group), butyl cellulose (R is a hydrogen atom or a butyl group), hydroxypropyl cellulose [R is a hydrogen atom or a hydroxypropyl group (group -[CH ₂ CH(CH ₃ )O] _m -H (wherein m is an integer of 1 to 5, preferably 1 to 3)], or hydroxypropyl methylcellulose (R is a hydrogen atom, a methyl group, or a hydroxypropyl group (same as above)), with a compound for introducing a long-chain alkyl group having 14 to 22 carbon atoms, specifically a long-chain alkyl glycidyl ether of formula (II) below, in the presence of an alkali catalyst.

［式中、Ｒ’は、炭素原子数が１４～２２のアルキル基である。］

[In the formula, R' is an alkyl group having 14 to 22 carbon atoms.]

The content of the group -CH ₂ CH(OH)CH ₂ OR' introduced into the hydrophobically modified alkyl cellulose of the present invention is preferably about 0.1 to 5.0% by mass based on the total amount of the hydrophobically modified alkyl cellulose. In order to achieve such a content, the molar ratio, reaction time, type of alkali catalyst, etc., of the reaction between the water-soluble cellulose ester derivative and the long-chain alkyl glycidyl ether may be appropriately selected for production. After the reaction, the reaction product may be subjected to purification steps such as neutralization, filtration, washing, drying, and sieving.

Among the above water-soluble cellulose ether derivatives, it is particularly preferable to select hydroxypropylmethylcellulose (as a result, R in formula (I) is any one of the four groups of a hydrogen atom, a methyl group, a group -[CH ₂ CH(CH ₃ )O] _m H, and a group -CH ₂ CH(OH)CH ₂ OR', q of group A is 1, and A is a methylene group).

Furthermore, R' in the long-chain alkyl glycidyl ether of formula (II) is an alkyl group having 14 to 22 carbon atoms, preferably an alkyl group having 14 to 20 carbon atoms, and more preferably a stearyl group ( _-C18H37 ) having ₁₈ carbon atoms. If the alkyl group R' has less than 14 carbon atoms or 23 or more carbon atoms, the emulsion stability of the obtained hydrophobically modified alkyl cellulose becomes insufficient.

The weight average molecular weight of the hydrophobically modified alkyl cellulose is preferably 100,000 to 1,000,000, more preferably 300,000 to 800,000, and even more preferably 550,000 to 750,000.

In the present invention, it is preferable to use hydrophobically modified hydroxypropyl methylcellulose (hydrophobized hydroxypropyl methylcellulose), more specifically, stearoxy hydroxypropyl cellulose, as the hydrophobically modified alkyl cellulose. In addition, commercially available products can be used as the hydrophobically modified alkyl cellulose, and examples thereof include, but are not limited to, Sangelose 90L (display name: hydrophobized hydroxypropyl methylcellulose; manufactured by Daido Chemical Industry Co., Ltd.), Natrosol Plus 330cs (manufactured by Ashland Co., Ltd.), and Polysurf 67cs (manufactured by Ashland Co., Ltd.).

In the cosmetic of the present invention, the content of hydrophobically modified alkyl cellulose is not particularly limited, and may be, for example, 0.05% by mass or more, 0.10% by mass or more, 0.15% by mass or more, 0.20% by mass or more, 0.25% by mass or more, 0.30% by mass or more, 0.35% by mass or more, 0.40% by mass or more, 0.45% by mass or more, or 0.50% by mass or more, or 1.0% by mass or less, 0.80% by mass or less, 0.50% by mass or less, or 0.30% by mass or less.

(c) Aqueous Phase Thickener
The aqueous phase thickener contained in the cosmetic of the present invention is a thickener that has the function of thickening the aqueous phase, and may be one that reduces the viscosity in the presence of electrolytes at concentrations in the range generally used in cosmetics. In the present invention, such aqueous phase thickeners that reduce the viscosity due to an increase in the electrolyte concentration are also referred to as "aqueous phase thickeners with low salt tolerance". Such thickeners with low salt tolerance are selected from water-soluble thickeners that have been conventionally used in cosmetics and the like for the purpose of adjusting the viscosity of the aqueous phase.

Specific examples include vinyl polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl methyl ether, polyvinylpyrrolidone, vinylpyrrolidone and vinyl acetate copolymers, and carboxyvinyl polymers; acrylic polymers such as sodium polyacrylate, polyethyl acrylate, polyacrylic alkanolamine, alkyl methacrylate and dimethylaminoethyl methacrylate copolymers, poly 2-acrylamido-2-methylpropanesulfonic acid, polymethacryloyloxytrimethylammonium, (ammonium acryloyldimethyltaurate/VP) copolymer, and dimethylacrylamide/Na acryloyldimethyltaurate crosspolymer, but are not limited to these.

However, among thickeners with low salt tolerance, thickeners that form water-swellable microgels in the aqueous phase and thicken due to friction between swollen microgel particles are preferred over thickeners that thicken due to entanglement of polymer chains, as this further suppresses stickiness when the cosmetic is applied to the skin. This is because the hydrophobically modified alkyl cellulose blended as an emulsifier also has a thickening effect due to entanglement of polymer chains, and further blending a thickener that thickens by the same mechanism may promote this thickening effect and cause stickiness.

In the cosmetic of the present invention, the content of the aqueous phase thickener is not particularly limited, and may be, for example, 0.05% by mass or more, 0.07% by mass or more, 0.10% by mass or more, 0.15% by mass or more, 0.17% by mass or more, 0.20% by mass or more, 0.25% by mass or more, 0.27% by mass or more, 0.275% by mass or more, 0.30% by mass or more, 0.35% by mass or more, 0.37% by mass or more, 0.40% by mass or more, 0.45% by mass or more, 0.47% by mass or more, or 0.50% by mass or more, or 3.0% by mass or less, 2.0% by mass or less, or 1.0% by mass or less.

(d) Oil Content
The oil contained in the cosmetic of the present invention can be one or more types selected from oily components commonly used in cosmetics and the like.

In the cosmetic of the present invention, the oil content is not particularly limited and may be, for example, 5.0% by mass or more, 6.0% by mass or more, 7.0% by mass or more, 8.0% by mass or more, 9.0% by mass or more, 10.0% by mass or more, 11.0% by mass or more, 12.0% by mass or more, 13.0% by mass or more, 14.0% by mass or more, 15.0% by mass or more, or 16.0% by mass or more, and may be 40.0% by mass or less, 30.0% by mass or less, or 20.0% by mass or less.

In the present invention, it is preferable that the oil contains polar oil. For example, in the cosmetic of the present invention, when 55% by weight or more of the oil is polar oil, preferably 60% by weight or more, more preferably 70% by weight or more, and even more preferably 80% by weight or more, the emulsion stability can be further improved. In addition, the upper limit of the proportion of polar oil in the oil is not particularly limited, and for example, polar oil may account for 90% or more, or 100% of the oil may be polar oil.

In the present invention, the "polar oil" is not particularly limited as long as it is an oil that is generally used in cosmetics and has a high polarity, but for example, an oil with a relative dielectric constant of about 5 or more, preferably about 10 or more, is preferably used.

Typical examples of polar oils include ester oils and UV absorbers. In addition, because it contains a larger amount of polar oil than conventional cosmetics, it is possible to stably incorporate, for example, highly polar fragrances.

(Ester oil)
Specific examples of ester oils that can be used as polar oils in the present invention include tripropylene glycol dineopentanoate, isononyl isononanoate, isopropyl myristate, cetyl octanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, lanolin acetate, isocetyl stearate, isocetyl isostearate, cholesteryl 12-hydroxystearate, cetyl ethylhexanoate, ethylene glycol di-2-ethylhexanoate, dipentaerythritol fatty acid esters, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, glycerin di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, tetra- Pentaerythrityl 2-ethylhexanoate, triethylhexanoin (tri-2-ethylhexanoic acid glycerin), trioctanoic acid glycerin, triisopalmitic acid glycerin, triisostearate trimethylolpropane, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, trimyristate glycerin, tri-2-heptylundecanoic acid glyceride, castor oil fatty acid methyl ester, oleyl oleate, acetoglyceride, palmitic acid Examples of the oleic acid ester include, but are not limited to, 2-heptylundecyl oleate, diisobutyl adipate, N-lauroyl-L-glutamic acid-2-octyldodecyl ester, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, 2-ethylhexyl succinate, and triethyl citrate.

(Ultraviolet absorber)
In the present invention, specific examples of ultraviolet absorbers that can be used as polar oils include, but are not limited to, benzoic acid derivatives, salicylic acid derivatives, cinnamic acid derivatives, dibenzoylmethane derivatives, β,β-diphenylacrylate derivatives, benzophenone derivatives, benzylidene camphor derivatives, phenylbenzimidazole derivatives, triazine derivatives, phenylbenzotriazole derivatives, anthranil derivatives, imidazoline derivatives, benzalmalonate derivatives, 4,4-diarylbutadiene derivatives, etc. Some specific examples and trade names of these will be described below as examples.

Examples of benzoic acid derivatives include, but are not limited to, ethyl para-aminobenzoate (PABA), ethyl-dihydroxypropyl PABA, ethylhexyl-dimethyl PABA (e.g., Escarol 507; manufactured by ISP), glyceryl PABA, PEG-25-PABA (e.g., Uvinal P25; manufactured by BASF), and diethylaminohydroxybenzoylhexyl benzoate (e.g., Uvinal A Plus).

Salicylic acid derivatives include, but are not limited to, homosalate (Eusolex HMS; Rona/EM Industries), ethylhexyl salicylate (e.g., NeoHeliopan OS; Herman & Reimer), dipropylene glycol salicylate (e.g., Dipsal; Skel), and TEA salicylate (e.g., NeoHeliopan TS; Herman & Reimer).

Cinnamic acid derivatives include, but are not limited to, ethylhexyl methoxycinnamate (e.g., Parsol MCX, manufactured by Hoffmann-La Roche), isopropyl methoxycinnamate, isoamyl methoxycinnamate (e.g., Neo Heliopan E1000, manufactured by Herman & Reimer), cinnoxate, DEA methoxycinnamate, diisopropyl methylcinnamate, glyceryl-ethylhexanoate-dimethoxycinnamate, and di-(2-ethylhexyl)-4'-methoxybenzalmalonate.

Dibenzoylmethane derivatives include, but are not limited to, 4-tert-butyl-4'-methoxydibenzoylmethane (e.g., Parsol 1789).

Examples of β,β-diphenylacrylate derivatives include, but are not limited to, octocrylene (e.g., "Uvinal N539" manufactured by BASF).

Benzophenone derivatives include, but are not limited to, benzophenone-1 (e.g., "Uvinal 400"; manufactured by BASF), benzophenone-2 (e.g., "Uvinal D50"; manufactured by BASF), benzophenone-3 or oxybenzone (e.g., "Uvinal M40"; manufactured by BASF), benzophenone-4 (e.g., "Uvinal MS40"; manufactured by BASF), benzophenone-5, benzophenone-6 (e.g., "Helisorb 11"; manufactured by Norquay), benzophenone-8 (e.g., "Spectra-Sorb UV-24"; manufactured by American Cyanamid), benzophenone-9 (e.g., "Uvinal DS-49"; manufactured by BASF), and benzophenone-12.

Examples of benzylidene camphor derivatives include, but are not limited to, 3-benzylidene camphor (e.g., "Mexoryl SD"; manufactured by Symex), 4-methylbenzylidene camphor, benzylidene camphor sulfonic acid (e.g., "Mexoryl SL"; manufactured by Symex), camphor benzalkonium methosulfate (e.g., "Mexoryl SO"; manufactured by Symex), terephthalide discamphor sulfonic acid (e.g., "Mexoryl SX"; manufactured by Symex), and polyacrylamide methyl benzylidene camphor (e.g., "Mexoryl SW"; manufactured by Symex).

Examples of phenylbenzimidazole derivatives include, but are not limited to, phenylbenzimidazole sulfonic acid (e.g., "Eusolex 232" manufactured by Merck) and disodium phenyldibenzimidazole tetrasulfonate (e.g., "Neo Heliopan AP" manufactured by Herman & Reimer).

Examples of triazine derivatives include, but are not limited to, anisotriazine (e.g., "Tinosorb S" manufactured by Ciba Specialty Chemicals), ethylhexyl triazone (e.g., "Uvinal T150" manufactured by BASF), diethylhexylbutamido triazone (e.g., "Uvasorb HEB" manufactured by Sigma 3V), and 2,4,6-tris(diisobutyl-4'-aminobenzalmalonate)-s-triazine.

Examples of phenylbenzotriazole derivatives include, but are not limited to, drometrizole trisiloxane (e.g., Silatrizole, manufactured by Rhodia-Chemie), and methylene bis(benzotriazolyl tetramethylbutylphenol) (e.g., Tinosorb M, manufactured by Ciba Specialty Chemicals).

Anthranil derivatives include, but are not limited to, menthyl anthranilate (e.g., "Neo Heliopan MA" manufactured by Herman & Reimer).

Imidazoline derivatives include, but are not limited to, ethylhexyl dimethoxybenzylidene dioxoimidazoline propionate.

Benzalmalonate derivatives include, but are not limited to, polyorganosiloxanes having benzalmalonate functional groups (e.g., polysilicone-15; "Parsol SLX"; manufactured by DSM Nutrition Japan).

Examples of 4,4-diarylbutadiene derivatives include, but are not limited to, 1,1-dicarboxy(2,2'-dimethylpropyl)-4,4-diphenylbutadiene.

<Other Ingredients>
In addition to the essential components (a) to (d) described above, the cosmetic preparation of the present invention may further contain other components within the scope of not impairing the effects of the present invention. The other components will be described below by way of example.

(e) Polyhydroxystearic acid
The cosmetic composition of the present invention may further contain polyhydroxystearic acid. Polyhydroxystearic acid is preferred from the viewpoint of having the effect of uniformly dispersing the metal oxide particles of the present invention in oil.

Polyhydroxystearic acid is a compound in which hydroxystearic acid is oligomerized by forming an ester bond, and commercially available products include, for example, HS Oligomer 600 (manufactured by Toyokuni Oil Mills Co., Ltd.) and Salacos HS-6C (manufactured by Nisshin Oillio Co., Ltd.), which can be used. There are no particular limitations on the degree of polymerization of polyhydroxystearic acid, and it may be, for example, 4 to 8.

In the cosmetic composition of the present invention, when polyhydroxystearic acid is contained, the content of polyhydroxystearic acid may be, for example, 0.01 to 3.0% by mass, 0.05 to 2.0% by mass, or 0.10 to 1.0% by mass.

((f) Ionic Surfactant)
The cosmetic preparation of the present invention may further contain an ionic surfactant. The ionic surfactant is preferred from the viewpoint of preventing the emulsion particles from coalescing due to electrostatic repulsion.

Ionic surfactants are surfactants that dissociate into ions when dissolved in water, and are specifically classified into anionic surfactants, cationic surfactants, amphoteric surfactants, etc.

Examples of ionic surfactants include anionic surfactants such as N-stearoyl-N-methyl taurine, sodium N-stearoyl-N-methyl taurine, disodium N-stearoyl-L-glutamate, sodium N-stearoyl-L-glutamate, sodium polyoxyethylene lauryl ether acetate, polyoxyethylene lauryl ether acetate triethanolamine, sodium laurate taurine, sodium lauroyl methyl taurine, and triethanolamine laurate; cationic surfactants such as stearyl dimethylamine oxide and stearyl trimethylammonium chloride; and amphoteric surfactants such as lauryl dimethyl betaine and lauryl dimethyl amino acetate betaine, but are not limited to these.

In the cosmetic composition of the present invention, when an ionic surfactant is contained, the content of the ionic surfactant may be, for example, 0.01 to 2.0% by mass, 0.05 to 1.0% by mass, or 0.10 to 0.50% by mass.

(Other surfactants)
With regard to nonionic surfactants ("nonionic surfactants"), the cosmetic preparation of the present invention may contain a nonionic surfactant with an HLB value of less than 10, so long as the content of nonionic surfactants with an HLB value of 10 or more is less than 1.0 mass%.

Examples of nonionic surfactants with an HLB value of less than 10 include, but are not limited to, bisbutyldimethicone polyglyceryl-3 (HLB value: 0.5), PEG-10 dimethicone (HLB value: 2.0), and PEG-9 polydimethylsiloxyethyl dimethicone (HLB value: 4.0).

When the cosmetic composition of the present invention further contains a nonionic surfactant with an HLB value of less than 10, the content of the nonionic surfactant may be, for example, 0.01 to 2.0% by mass, or 0.05 to 1.0% by mass.

In addition to the above-mentioned surfactants, for example, polymeric surfactants or natural surfactants may be further blended into the cosmetic composition of the present invention as long as they do not impair the effects of the present invention.

((g) Water-soluble polyether modified silicone wax)
The cosmetic of the present invention may further contain a water-soluble polyether-modified silicone wax. The water-soluble polyether-modified silicone wax is preferred from the viewpoint of making the cosmetic of the present invention non-sticky, further improving the emulsion stability, and providing a refreshing emulsion.

Examples of water-soluble polyether-modified silicone waxes include, but are not limited to, bisPEG-18 methyl ether dimethyl silane, bisPEG-15 methyl ether dimethicone, PEG-32 methyl ether dimethicone, and PEG-17 dimethicone.

Water-soluble polyether-modified silicone waxes can be obtained commercially, and examples include, but are not limited to, CosmeticWax 2501 (manufactured by Dow Corning Toray Co., Ltd., bisPEG-18 methyl ether dimethylsilane, melting point 36 to 42°C), DMC 6038 (manufactured by Wacker, bisPEG-15 methyl ether dimethicone, melting point approximately 30°C), KF-6004 (manufactured by Shin-Etsu Chemical Co., Ltd., PEG-32 methyl ether dimethicone, melting point 45°C), and Silsoft (registered trademark) 895 (manufactured by MOMENTIVE, PEG-17 dimethicone).

In the cosmetic composition of the present invention, when the cosmetic composition contains a water-soluble polyether-modified silicone wax, the content of the water-soluble polyether-modified silicone wax may be, for example, 0.1 to 20.0% by mass, 0.5 to 15.0% by mass, or 1.0 to 10.0% by mass.

(h) Cooling Agents
The cosmetic preparation of the present invention may further contain a cooling agent. The cooling agent is preferable from the viewpoint of enhancing a feeling of coolness.

The cooling agent may be one or more selected from the group consisting of menthol, peppermint oil, l-menthyl glyceryl ether, menthyl lactate, camphor, isopulegol, bornol, cineole menthone, spearmint, peppermint, menthyl malonate, glycosyl-mono-menthyl-O-acetate, 3-L-menthoxypropane-1,2-diol, and 1-menthyl-3-hydroxybutyrate.

In the cosmetic composition of the present invention, when a water refreshing agent is included, the content of the water refreshing agent may be, for example, 0.1 to 10.0% by mass, 0.5 to 10.0% by mass, or 1.0 to 5.0% by mass.

In addition to the "other ingredients" described above, the cosmetic composition of the present invention may contain, for example, glycols such as propylene glycol, dipropylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol; glycerins such as glycerin, diglycerin, and polyglycerin; sugar alcohols such as sorbitol, mannitol, maltitol, xylitol, and erythritol; sugars such as fructose, glucose, galactose, maltose, lactose, and trehalose; natural pigments such as chlorophyll and β-carotene; plant-based polymers such as gum arabic, gum tragacanth, galactan, guar gum, carob gum, karaya gum, gellan gum, and carrageenan; microbial polymers such as xanthan gum, dextran, succinoglucan, and pullulan; and animal-based polymers such as collagen, casein, albumin, and gelatin. starch-based polymers such as carboxymethyl starch and methylhydroxypropyl starch; cellulose-based polymers such as methylcellulose, ethylcellulose, methylhydroxypropylcellulose, hydroxyethylcellulose, sodium cellulose sulfate, hydroxypropylcellulose, sodium carboxymethylcellulose, and crystalline cellulose; alginic acid-based polymers such as sodium alginate and propylene glycol alginate; other thickeners; vitamins such as magnesium ascorbyl phosphate, ascorbyl glucoside, vitamin B6 hydrochloride, and pantothenyl ethyl ether; drugs such as bactericides, anti-inflammatory agents, preservatives, plant extracts, and amino acids; lower alcohols such as ethanol and isopropyl alcohol; aromatic alcohols such as phenoxyethanol and benzyl alcohol; or silica, and other various components that are usually incorporated into cosmetics.

The cosmetic of the present invention can be prepared according to a method commonly used for oil-in-water emulsion cosmetics. That is, the cosmetic can be prepared by mixing the aqueous phase component and the oil phase component separately, and emulsifying the aqueous phase component by adding the oil phase component while stirring the aqueous phase component.

The cosmetic of the present invention may have an emulsion particle size of 7.5 μm on average and approximately 20 μm at maximum, but is not particularly limited to this size. The emulsion particle size can be determined, for example, by using a microscope to comprehensively determine the size of the emulsion particles (measured with a micrometer) and their distribution (uniformity of particles in the field of view) with the naked eye.

The cosmetic of the present invention may be an infrared protective cosmetic since it can exert the effects of the present invention described above.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these. In the following, the contents are shown in mass % unless otherwise specified.

The cosmetics of the examples and comparative examples were prepared according to the formulations shown in Table 1 below, and the stability, infrared cut rate, usability, and emulsion particle size of each obtained cosmetic were evaluated according to the following criteria, and the results are shown in Table 2.

Stability
Each of the cosmetics obtained in the Examples and Comparative Examples was filled into two screw tubes (50 ml) and left to stand for two weeks in a thermostatic bath at 0° C. or 50° C. Before and after standing, the change in viscosity was measured using a rotational viscometer (Vismetron rotational viscometer), and the emulsion particles and appearance were observed:
"Evaluation Criteria"
"A": No decrease in viscosity was observed at either temperature level of 0°C or 50°C, and there were no problems with the emulsion particles or appearance.
"B": At any temperature level, a slight decrease in viscosity, an increase in emulsified particles, or a change in appearance was observed.
"C": Protrusion of metal oxide particles was observed at any temperature level.

<Infrared blocking rate>
Each cosmetic obtained in the examples and comparative examples was applied to a PMMA (polymethyl methacrylate resin) substrate (HD6 manufactured by HelioScreen) and dried for 15 minutes to prepare a measurement sample. In addition, an uncoated PMMA substrate was used as a control sample. The transmittance at 1500 nm was measured for each of the measurement sample and the control sample using a spectrophotometer (UV-3600 manufactured by Shimadzu Corporation, integrating sphere mode). During the measurement, the coated surface of the PMMA substrate was attached to the outer edge of the opening of the integrating sphere using double-sided tape. The transmittance of the measurement sample divided by the transmittance of the control sample was determined as the transmittance, and (100% - transmittance) was determined as the infrared cut rate (%).

<Usage sensation>
The cosmetic compositions obtained in the Examples and Comparative Examples were evaluated by a panel of three experts on the feel of use, based on the following criteria:
"A": Very fresh.
"B": Excellent freshness.
"C": Less fresh.

<Emulsion particle size>
Using a microscope, the size of the emulsion particles (measured with a micrometer) and their distribution (uniformity of particles in the field of view of the microscope) were comprehensively judged with the naked eye to determine the emulsion particle size of each of the cosmetics obtained in the Examples and Comparative Examples. Note that in Table 2, the expression "1-10 (20)" means that the majority of the emulsion particles had a diameter in the range of about 1-10 μm, with a small number of emulsion particles up to about 20 μm being present. The same applies to other expressions.

As is clear from Table 1, the cosmetics of Examples 1 to 9 were found to have excellent infrared protection effects and a unique, refreshing feel when used.

The cosmetics of Examples 1 to 6 are more stable than the cosmetics of Examples 7 to 9, which is believed to be due to the inclusion of polyhydroxystearic acid. The cosmetics of Examples 7 to 9 further contain surfactants such as sorbitan sesquiisostearate, isostearic acid, and bisbutyldimethicone polyglyceryl-3, instead of polyhydroxystearic acid. These surfactants function as powder dispersants, but their dispersibility, especially for large metal oxide particles, is considered to be somewhat inferior to that of polyhydroxystearic acid.

Claims (10)

Contains the following components (a) to (d):
(a) metal oxide particles having an average particle size of 500 to 1,500 nm and having a hydrophobic surface;
(b) hydrophobically modified alkyl cellulose;
(c) an aqueous phase thickener; and (d) an oil.
the metal oxide particles are dispersed in the oil, and the content of a nonionic surfactant having an HLB value of 10 or more is less than 1.0 mass%.
Oil-in-water emulsion cosmetic. The cosmetic preparation according to claim 1, further comprising (e) polyhydroxystearic acid. The content of the metal oxide particles is 1.0% by mass or more and 30.0% by mass or less,
The content of the hydrophobically modified alkyl cellulose is 0.05% by mass or more and 1.0% by mass or less,
The content of the aqueous phase thickener is 0.05% by mass or more and 3.0% by mass or less, and the content of the oil content is 5.0% by mass or more and 40.0% by mass or less.
The cosmetic preparation according to claim 1 or 2. The cosmetic according to any one of claims 1 to 3, wherein the metal oxide particles are titanium oxide. The cosmetic preparation according to any one of claims 1 to 4, wherein the hydrophobically modified alkyl cellulose is hydrophobically modified hydroxypropyl methyl cellulose. The cosmetic preparation according to any one of claims 1 to 5, wherein the aqueous phase thickener comprises a vinyl polymer or an acrylic polymer. The cosmetic preparation according to any one of claims 1 to 6, in which 55% by mass or more of the oil content is polar oil. The cosmetic preparation according to any one of claims 1 to 7, further comprising (f) an ionic surfactant. The cosmetic preparation according to any one of claims 1 to 8, further comprising (g) a water-soluble polyether-modified silicone wax. The cosmetic composition according to any one of claims 1 to 9, which is an infrared ray protection cosmetic composition.