JP7604221B2 - Oil-in-water emulsion cosmetics - Google Patents

Description

The present invention relates to an oil-in-water emulsion cosmetic that can stably incorporate an ultraviolet scattering agent and a pigment in a cosmetic base that contains a reduced amount of silicone compound.

Silicone compounds such as silicone oil are characterized by their high water repellency, non-sticky, light feel when used, and good spreadability on the skin, and are effective in improving the water resistance and feel of cosmetics containing them, as well as the dispersibility of other compounded ingredients. Furthermore, silicone compounds are also widely used as surface treatment agents for powdered ingredients.

Although silicone compounds have the advantages mentioned above, they have the problem that their high water repellency makes it difficult to remove makeup with water and makes them poorly cleansable. Furthermore, because silicone compounds are not usually biodegradable, there are concerns that they will accumulate in the environment for long periods of time, posing a risk of environmental pollution and disrupting the ecosystem. As a result, in recent years, so-called "silicone-free" cosmetics that do not contain silicone compounds have been attracting attention.

However, removing the silicone compounds that contribute to improving the dispersibility of other ingredients such as powders in conventional cosmetics creates problems such as making it difficult to maintain the stability of the cosmetics.

On the other hand, it is common for cosmetics to contain ultraviolet absorbing agents and ultraviolet scattering agents to protect the skin from the harmful effects of ultraviolet rays. Typically, organic compounds such as ethylhexyl methoxycinnamate and octocrylene are used as ultraviolet absorbing agents, while inorganic powder components such as titanium dioxide and zinc oxide are used as ultraviolet scattering agents.

UV absorbers have the advantages of being highly transparent, spreading easily on the skin, and not easily worn down by sweat. However, because they protect against the effects of UV rays by converting them into other forms of energy such as heat energy, they can be irritating to users with sensitive skin. As a result, there is demand for UV absorber-free, or so-called "non-chemical" cosmetics that achieve UV protection without using UV absorbers, but instead rely on UV scattering agents.

For example, Patent Document 1 proposes an oil-in-water emulsion cosmetic that has good powder dispersibility and texture by using a metal soap consisting of a higher fatty acid and a divalent metal as a surface treatment agent for the powder.

However, with the cosmetic described in Patent Document 1, no consideration was given to whether sufficient stability would be obtained when the cosmetic is subjected to vibration, such as when carried around.

International Publication No. 2017/006488

The present invention aims to provide an oil-in-water emulsion base that has excellent powder dispersibility, particularly vibration stability, even when a high amount of UV scattering agent and pigment is added to a cosmetic base in which the amount of silicone compound is reduced.

As a result of intensive research into solving the above problems, the inventors discovered that by surface-treating the pigment to be blended in the oil phase with a surface-treating agent containing glutamic acid or aspartic acid acylated with a saturated fatty acid having 8 to 14 carbon atoms or a salt thereof, and blending a water-soluble alkyl-substituted polysaccharide derivative, the dispersibility of the powder in the oil phase, which is the internal phase, is significantly improved without blending a silicone compound, and thus completed the present invention.

That is, the present invention provides
(A) a pigment that has been surface-treated with a surface treatment agent containing glutamic acid or aspartic acid acylated with a saturated fatty acid having 8 to 14 carbon atoms or a salt thereof;
(B) oil,
(C) a hydrophobic ultraviolet scattering agent, and (D) a water-soluble alkyl-substituted polysaccharide derivative,
The blending amount of the ultraviolet absorber is less than 1 mass% based on the total amount of the cosmetic,
The silicone oil is contained in an amount of 10% by mass or less based on the total amount of the cosmetic,
The present invention provides an oil-in-water emulsion cosmetic, characterized in that the components (A) and (C) are dispersed in an oil phase.

The cosmetic composition according to the present invention, by being configured as described above, can improve the vibrational stability and emulsion stability of the emulsion base containing a high content of pigment and UV scattering agent without the inclusion of a silicone compound. This makes it possible to realize a silicone-free makeup cosmetic composition that is suitable for carrying around. Furthermore, according to the present invention, a sufficient UV protection effect can be obtained by the high content of UV scattering agent without the inclusion of a UV absorber, making it possible to realize a non-chemical cosmetic composition.

The cosmetic of the present invention is characterized by containing (A) a pigment that has been surface-treated with a surface treatment agent containing glutamic acid or aspartic acid acylated with a saturated fatty acid having 8 to 14 carbon atoms or a salt thereof, (B) an oil, (C) a hydrophobic ultraviolet scattering agent, and (D) a water-soluble alkyl-substituted polysaccharide derivative. Each component constituting the cosmetic of the present invention is described in detail below.

<(A) Pigment>
The pigment (A) blended in the cosmetic preparation according to the present invention (hereinafter, may be simply referred to as "component (A)") refers to an inorganic pigment that has been surface-treated with a surface treatment agent containing glutamic acid or aspartic acid acylated with a saturated fatty acid having 8 to 14 carbon atoms, or a salt thereof. By using a pigment that has been surface-treated with such a specific treatment agent, a cosmetic preparation that has excellent powder dispersibility and stability over time can be obtained. As the surface treatment agent for the pigment of the present invention, only glutamic acid or aspartic acid acylated with a saturated fatty acid having 8 to 14 carbon atoms, or a salt thereof, may be used, or in addition to glutamic acid or aspartic acid acylated with a saturated fatty acid having 8 to 14 carbon atoms, or a salt thereof, other compounds that are generally used as surface treatment agents for powders may be further included.

Specific examples of pigments include iron oxide (red iron oxide), iron titanate, gamma-iron oxide, yellow iron oxide, yellow ochre, black iron oxide, carbon black, low-order titanium oxide, mango violet, cobalt violet, chromium oxide, chromium hydroxide, cobalt titanate, ultramarine, and iron blue. Of these, it is preferable to use pigment-grade iron oxides such as yellow iron oxide, red iron oxide, and black iron oxide, and pigment-grade titanium oxide, etc., as the pigment of the present invention. Here, pigment-grade refers to those having an average particle size of 100 nm to 1 μm.

"Glutamic acid or aspartic acid acylated with a saturated fatty acid having 8 to 14 carbon atoms, or a salt thereof" refers to a compound in which an acyl group, specifically a saturated fatty acid having 8 to 14 carbon atoms, is condensed with the amino group of glutamic acid or aspartic acid, or a salt thereof. Examples of saturated fatty acids having 8 to 14 carbon atoms include caprylic acid, lauric acid, and myristic acid, and examples of the "acyl group" include capryloyl, lauroyl, and myristoyl groups. The "salt" can be selected from alkali metal salts such as sodium and potassium, and alkaline earth metal salts, with sodium salts being preferred. Specific examples of acylated amino acids include sodium lauroyl glutamate and sodium lauroyl aspartate.

The surface treatment agent in the present invention may contain other treatment agents in addition to the glutamic acid or aspartic acid acylated with the saturated fatty acid or the salt thereof. Examples of other treatment agents include "amino acids", "esters" and "metal complexes of esters". The "amino acids" are not particularly limited, but are preferably selected from aspartic acid, glutamic acid and lysine, with lysine being particularly preferred. The "esters" are compounds in which a monovalent or divalent fatty acid having 8 to 12 carbon atoms is bonded to a saturated aliphatic alcohol having 12 to 20 carbon atoms via an ester bond, and the alkyl chains of the fatty acid and the aliphatic alcohol may be linear or branched, and specific examples include isostearyl sebacate. The "metal complexes of esters" are compounds in which an ester is coordinately bonded to a metal atom, and a preferred example is isopropyl titanium triisostearate.

The pigment (A) of the present invention can be prepared by adsorbing an acylated amino acid or its salt onto the pigment surface in a conventional manner.

The pigment (A) used in the present invention is preferably a pigment that has been surface-treated with a surface treatment agent containing sodium lauroyl glutamate and lysine (ASL treatment agent), or a surface treatment agent containing sodium lauroyl aspartate and isopropyl titanium triisostearate (ASI treatment agent).

Commercially available products can also be used as the pigment (A) of the present invention. Preferred commercially available products include, for example, ASL-treated powders such as ASL-1 TiO2 CR-50, ASL-Red R516P, ASL-Yellow LL-100P, and ASL-Black BL-100P, and ASI-treated powders such as ASI TiO2 CR-50, ASI-Red R516P, ASI-Yellow LL-100P, ASI-Black BL-100P, and ASI-Talc JA46R (all manufactured by Daito Kasei Kogyo Co., Ltd.).

The cosmetic composition of the present invention may contain one or a combination of two or more of the pigments treated with the above-mentioned surface treatment agent.
The total amount of the pigment (A) is not particularly limited as long as the desired color is obtained, but is usually 0.1% by mass or more, for example, 1 to 20% by mass, and preferably 2 to 10% by mass, based on the total amount of the cosmetic. If the amount is less than 1% by mass, a sufficient color cannot be obtained, and if it exceeds 20% by mass, stability tends to deteriorate.

<(B) Oil Content>
The oil (B) (hereinafter sometimes simply referred to as "component (B)") blended in the cosmetic preparation according to the present invention is not particularly limited as long as it is an oil that is usually blended in cosmetics, and examples include hydrocarbon oils, ester oils, higher alcohols having 12 to 22 carbon atoms, fatty acids having 12 to 22 carbon atoms, oils and fats, waxes, etc. The cosmetic preparation of the present invention can be stably blended with even polar oils that have conventionally been thought to reduce emulsion stability.

However, in the cosmetic of the present invention, the amount of silicone oil is 10% by mass or less, preferably 5% by mass or less, and more preferably 1% by mass or less, based on the total amount of the cosmetic. The cosmetic of the present invention also includes an embodiment in which silicone oil is not substantially blended.

Examples of hydrocarbon oils include liquid paraffin, isohexadecane, isododecane, ozokerite, squalane, squalene, pristane, paraffin, isoparaffin, ceresin, petrolatum, microcrystalline wax, hydrogenated polyisobutene, olefin oligomers, and volatile hydrocarbon oils (e.g., isododecane, isohexadecane, undecane, tridecane, etc.).

Examples of ester oils include isopropyl myristate, cetyl ethylhexanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, isocetyl stearate, isocetyl isostearate, cholesteryl 12-hydroxystearate, ethylene glycol di-2-ethylhexanoate, dipentaerythritol fatty acid ester, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, glycerin di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, glycerin triisostearate, pentaerythrityl tetraethylhexanoate, triisostearate, glycerin ... Ethylhexanoin (glyceryl tri-2-ethylhexanoate), cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, glycerin trimyristate, tri-2-heptylundecanoic acid glyceride, castor oil fatty acid methyl ester, oleyl oleate, cetostearyl alcohol, acetoglyceride, 2-heptylundecyl palmitate, diisobutyl adipate, N-lauroyl-L-glutamic acid Examples of triester oils include 2-octyldodecyl, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, 2-ethylhexyl succinate, polypropylene glycol dipivalate, ethyl acetate, butyl acetate, amyl acetate, and triethyl citrate.

Examples of higher alcohols having 12 to 22 carbon atoms include oleyl alcohol, 2-decyltetradecyl alcohol, dodecanol, isostearyl alcohol, octyldodecanol, etc. Examples of fatty acids having 12 to 22 carbon atoms include oleic acid, isostearic acid, linoleic acid, linolenic acid, etc.

Examples of fats and oils include Japanese wax, cacao butter, hardened castor oil, avocado oil, camellia oil, macadamia nut oil, corn oil, olive oil, rapeseed oil, sesame oil, persic oil, wheat germ oil, sasanqua oil, castor oil, linseed oil, safflower oil, cottonseed oil, perilla oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, Chinese tung oil, Japanese tung oil, jojoba oil, germ oil, triglycerin, glycerin trioctanoate, glycerin triisopalmitate, etc.

Examples of waxes include carnauba wax, beeswax, candelilla wax, jojoba wax, etc.

In the cosmetic of the present invention, the dispersion stability of the powder is improved when the ratio of polar oil to the total amount of oil is 40% or more by mass. Therefore, in the cosmetic of the present invention, it is preferable that the ratio of polar oil to the total amount of oil (B) is 40% or more.

Polar oils include oils with an IOB value of 0.05 to 0.80, particularly ester oils. Specific examples of polar oils include isostearic acid, isopropyl myristate, cetyl octanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, isononyl isononanoate, cetyl lactate, myristyl lactate, isocetyl stearate, isocetyl isostearate, cetyl ethylhexanoate, cholesteryl 12-hydroxystearate, and ethylene glycol di-2-ethylhexanoate. Licor, dipentaerythritol fatty acid ester, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, di-2-heptylundecanoate glycerin, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, pentaerythritol tetra-2-ethylhexanoate, glyceryl tri-2-ethylhexanoate (triethylhexanoin), cetyl isooctanoate, cetyl 2-ethylhexanoate, palmitate 2-Ethylhexyl phosphate, C12-15 alkyl benzoate, cetearyl isononanoate, caprylic/capric triglyceride, butylene glycol dicaprylic/capric acid, glycerin trimyristate, tri-2-heptylundecanoic acid glyceride, castor oil fatty acid methyl ester, oleyl oleate, cetostearyl alcohol, acetoglyceride, 2-heptylundecyl palmitate, diisobutyl adipate, 2-octyldodecyl N-lauroyl-L-glutamate ester, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, di-2-ethylhexyl succinate, ethyl acetate, butyl acetate, amyl acetate, triethyl citrate, 2-ethylhexyl paramethoxycinnamate, tripropylene glycol dipivalate, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, etc.

The amount of (B) oil is not particularly limited as long as it is an amount normally used when blending powders such as pigments and UV scattering agents into the oil phase, but for example, it may be 5 to 50% by mass based on the total amount of the cosmetic. If the amount of oil exceeds 50% by mass, stability and usability tend to decrease.

<(C) Hydrophobic UV Scattering Agent>
The hydrophobic ultraviolet scattering agent (C) (hereinafter, sometimes simply referred to as "component (D)") blended in the cosmetic of the present invention can be appropriately selected from those commonly used in cosmetics, and is not particularly limited, but refers to those whose particle surface is hydrophobic. Specific examples include metal oxides such as titanium oxide, zinc oxide, iron oxide, cerium oxide, and tungsten oxide. In the present invention, titanium oxide and zinc oxide are preferred. Also, fine particles having an average particle size of 0.1 μm or less are preferred. The lower limit of the average particle size is not particularly limited, but is usually about 5 nm.

The ultraviolet scattering agent used in the present invention may be either untreated or hydrophobized, so long as the particle surface is hydrophobic. Examples of hydrophobizing surface treatment agents include, but are not limited to, silicone treatment agents, fluorine compound treatment agents, amino acid treatment agents, fatty acid treatment agents, fatty acid soap treatment agents, fatty acid ester treatment agents, and others such as lecithin treatment agents and alkyl phosphate ester treatment agents.

Examples of silicone treatment agents include silicone oils such as methylhydrogenpolysiloxane, dimethylpolysiloxane, and methylphenylpolysiloxane; alkyl silanes such as methyltrimethoxysilane, ethyltrimethoxysilane, hexyltrimethoxysilane, and octyltrimethoxysilane; and fluoroalkyl silanes such as trifluoromethylethyltrimethoxysilane and heptadecafluorodecyltrimethoxysilane. Examples of fluorine compound treatment agents include perfluoroalkyl phosphate esters and perfluoroalcohols. Examples of amino acid treatment agents include N-acyl glutamic acid, N-acylaspartic acid, and N-acylysine. Examples of fatty acid treatment agents include palmitic acid, isostearic acid, stearic acid, lauric acid, myristic acid, behenic acid, oleic acid, rosin acid, and 12-hydroxystearic acid. Examples of fatty acid soap treatment agents include aluminum stearate, calcium stearate, and aluminum 12-hydroxystearate. Examples of fatty acid ester treatment agents include dextrin fatty acid esters, cholesterol fatty acid esters, sucrose fatty acid esters, starch fatty acid esters, etc. These hydrophobic treatments can be carried out according to conventional methods.

According to the cosmetic of the present invention, the ultraviolet scattering agent can be blended in a high amount in the oil phase, so that a sufficient ultraviolet protection effect can be achieved without blending an ultraviolet absorbing agent. Therefore, in the cosmetic of the present invention, the blending amount of the ultraviolet absorbing agent is 3 mass % or less, and preferably 1 mass % or less, based on the total amount of the cosmetic. The cosmetic of the present invention also includes an embodiment in which substantially no ultraviolet absorbing agent is blended. By blending substantially no ultraviolet absorbing agent, it is possible to make the cosmetic "non-chemical".

"Non-chemical" cosmetics are cosmetics that contain inorganic UV scattering agents rather than organic UV absorbing agents, and thus provide skin protection from UV rays.

The amount of (C) UV scattering agent blended is the amount required to obtain the desired UV protection effect, and is not particularly limited, but is usually 1% by mass or more, for example 5 to 30% by mass, and preferably 10 to 30% by mass, relative to the total amount of the cosmetic. If the blended amount is less than 5% by mass, it is difficult to obtain a sufficient UV protection effect, and if it exceeds 30% by mass, stability tends to deteriorate. When the cosmetic of the present invention is prepared as a non-chemical cosmetic, it is preferable that the total content of the UV scattering agent is 10% by mass or more.

<(D) Water-soluble alkyl-substituted polysaccharide derivative>
The water-soluble alkyl-substituted polysaccharide derivative (D) (hereinafter, simply referred to as "component (D)") used in the cosmetic of the present invention is not particularly limited, but examples thereof include hydrophobically modified alkyl cellulose, hydrophobically modified sulfonated polysaccharide derivatives, and the like.

The hydrophobically modified alkyl cellulose is preferably an alkyl cellulose hydrophobically modified with an alkyl group having 14 to 22 carbon atoms. More specifically, it is a compound in which a long-chain alkyl group, which is a hydrophobic group, is introduced into a water-soluble cellulose ether derivative, and is preferably represented by the following general formula (I).

[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 hydrophobically modified alkyl cellulose of the formula (I) can be produced by 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)], hydroxypropyl methylcellulose (R is a hydrogen atom, a methyl group, or a hydroxypropyl group (same as above)), or the like, with a compound for introducing a long-chain alkyl group having 14 to 22 carbon atoms, specifically, a long-chain alkyl glycidyl ether of the following formula (II), in the presence of an alkali catalyst.
[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 four groups: 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 may be 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.

The hydrophobically modified sulfonated polysaccharide derivative preferably has a polysaccharide or a derivative thereof as a basic skeleton, and some or all of the hydrogen atoms of the hydroxyl groups are substituted with the following substituents (a) and (b). The substituent (a) is preferably a glyceryl ether group having a hydrophobic portion selected from an alkyl glyceryl ether group having a linear or branched alkyl group with 10 to 40 carbon atoms and an alkenyl glyceryl ether group having a linear or branched alkenyl group with 10 to 40 carbon atoms. The substituent (b) is preferably a sulfoalkyl group having 1 to 5 carbon atoms, which may be substituted with a hydroxyl group, or a salt thereof. Here, water-soluble refers to a material that dissolves in water at 25°C at a rate of 0.001% by mass or more.

Specific examples of the substituent (a) include, but are not limited to, a 2-hydroxy-3-alkoxypropyl group, a 2-alkoxy-1-(hydroxymethyl)ethyl group, a 2-hydroxy-3-alkenyloxypropyl group, and a 2-alkenyloxy-1-(hydroxymethyl)ethyl group. As the alkyl or alkenyl group having 10 to 40 carbon atoms that substitutes for these glyceryl ether groups, linear or branched alkyl and alkenyl groups having 12 to 36 carbon atoms, and more preferably 16 to 24 carbon atoms, are preferred, with alkyl groups being more preferred, and linear alkyl groups being more preferred.

Specific examples of the substituent (b) include, but are not limited to, a 2-sulfoethyl group, a 3-sulfopropyl group, a 3-sulfo-2-hydroxypropyl group, and a 2-sulfo-1-(hydroxymethyl)ethyl group, all or a part of which may be in the form of a salt with an alkali metal such as Na or K, an alkaline earth metal such as Ca or Mg, an organic cation group such as an amine, or an ammonium ion.

The degree of substitution of the substituent (a) is preferably 0.001 to 1 per constituent monosaccharide residue, more preferably 0.002 to 0.5, and even more preferably 0.003 to 0.1. The degree of substitution of the substituent (b) is preferably 0.01 to 2.5 per constituent monosaccharide residue, more preferably 0.02 to 2, and even more preferably 0.1 to 1.5. The ratio of the number of the substituents (a) to the number of the substituents (b) is preferably 1:1,000 to 100:1, more preferably 1:500 to 10:1, and even more preferably 1:300 to 10:1.

The polysaccharide or derivative thereof that serves as the basic skeleton of the hydrophobically modified sulfonated polysaccharide derivative is not particularly limited, but examples thereof include cellulose, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, and hydroxypropyl cellulose. The weight average molecular weight of these polysaccharides or derivatives is preferably 10,000 to 10,000,000, more preferably 100,000 to 5,000,000, and even more preferably 300,000 to 2,000,000.

The component (D) used in the cosmetic of the present invention is not particularly limited, but examples include hydrophobically modified alkylcelluloses such as stearoxy hydroxypropyl methylcellulose and laureth-13 PG hydroxyethylcellulose; and hydrophobically modified sulfonated polysaccharide derivatives such as stearoxy PG hydroxyethylcellulose sulfonate. Of these, stearoxy hydroxypropyl methylcellulose or stearoxy PG hydroxyethylcellulose sulfonate are more preferred.

In the present invention, commercially available products can also be used as component (D). For example, examples of stearoxy hydroxypropyl methylcellulose include Sangelose 60L (manufactured by Daido Chemical Industry Co., Ltd.) and Sangelose 90L (manufactured by Daido Chemical Industry Co., Ltd.), and examples of stearoxy PG hydroxyethyl cellulose sulfonate include Poise 310 (manufactured by Kao Corporation).

The amount of component (D) in the cosmetic of the present invention is 0.01 to 1% by mass, preferably 0.05 to 0.5% by mass, and more preferably 0.1 to 0.3% by mass, based on the total amount of the cosmetic. If the amount is less than 0.05% by mass, sufficient emulsion stability cannot be obtained, and even if the amount exceeds 1% by mass, it is difficult to obtain a further increase in effect.

In the cosmetic of the present invention, the stability and usability can be improved by further blending a water-soluble thickener other than the water-soluble alkyl-substituted polysaccharide derivative (D). The water-soluble thickener used in the present invention can be appropriately selected from substances used as thickening emulsifiers blended in the aqueous phase of ordinary emulsion-type cosmetics, etc.

Examples of water-soluble thickeners include plant-based polymers such as gum arabic, tragacanth, galactan, carob gum, guar gum, karaya gum, carrageenan, xanthan gum, pectin, agar, quince seed, and algae colloid (brown algae extract); microbial polymers such as gellan gum, dextran, succinoglucan, and pullulan; animal polymers such as collagen, casein, albumin, and gelatin; starch-based polymers such as starch (rice, corn, potato, and wheat), carboxymethyl starch, and methylhydroxypropyl starch; cellulose-based polymers such as methylcellulose, nitrocellulose, ethylcellulose, methylhydroxypropylcellulose, hydroxyethylcellulose, sodium cellulose sulfate, hydroxypropylcellulose, sodium carboxymethylcellulose, crystalline cellulose, and cellulose powder; sodium alginate, alginic acid, and the like. Examples of such polymers include alginic acid polymers such as propylene glycol esters, vinyl polymers such as polyvinyl methyl ether and carboxyvinyl polymers, polyoxyethylene polymers, polyoxyethylene polyoxypropylene copolymer polymers, acrylic polymers such as polyethyl acrylate and polyacrylamide, polyethyleneimine, cationic polymers, inorganic water-soluble polymers such as bentonite, magnesium aluminum silicate, laponite, hectorite, and silicic anhydride, PEG-240/decyltetradeceth-20/hexamethylene diisocyanate copolymers, (dimethylacrylamide/sodium acryloyldimethyltaurate) crosspolymers, (sodium acrylate/acryloyldimethyltaurate) copolymers, (alkyl acrylate/steareth-20 methacrylate) copolymers, and (ammonium acryloyldimethyltaurate/vinylpyrrolidone) copolymers.

In the cosmetic of the present invention, among the aqueous phase thickeners, if a thickener with low salt tolerance that reduces viscosity in the presence of electrolytes at concentrations in the range generally used in cosmetics (hereinafter also referred to as a "thickener that reduces viscosity due to an increase in electrolyte concentration") is used, a unique, fresh feel can be obtained when the cosmetic is applied to the skin.

In the present invention, the "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, while at the same time providing an extremely fresh feel as it spreads over the skin.

Thickeners that cause a decrease in viscosity due to an increase in electrolyte concentration are not particularly limited, but examples include vinyl polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl methyl ether, polyvinylpyrrolidone, copolymers of vinylpyrrolidone and vinyl acetate, and carboxyvinyl polymers; and acrylic polymers such as sodium polyacrylate, polyethyl acrylate, alkanolamine polyacrylate, copolymers of alkyl methacrylate and dimethylaminoethyl methacrylate, poly2-acrylamido-2-methylpropanesulfonic acid, polymethacryloyloxytrimethylammonium, (ammonium acryloyldimethyltaurate/vinylpyrrolidone) copolymer, and (dimethylacrylamide/Na acryloyldimethyltaurate) crosspolymer.

As the water-soluble thickener of the present invention, one or more kinds selected from the above substances may be used in combination.
The blending amount of the water-soluble thickener in the cosmetic of the present invention is preferably 0.05 to 3 mass %, more preferably 0.1 to 2 mass %, and even more preferably 0.15 to 1 mass %, based on the total amount of the cosmetic.

According to the cosmetic of the present invention, it is possible to realize a "silicone-free" cosmetic that does not contain any silicone compounds.
In this specification, "silicone compound" refers to compounds having a siloxane (-Si-O-Si-) structure in the molecule (e.g., silicones and siloxanes) and silanes (monosilane, oligosilane, polysilane, and silane derivatives such as alkylsilane and alkoxysilane), and includes silicone oil, silicone elastomer, silicone surfactant, and powder surface-treated with a silicone compound. Note that silicon dioxide (silica) is not included in the "silicone compound" of the present invention.

By combining the pigment treated with the specific surface treatment agent and the water-soluble alkyl-substituted polysaccharide derivative, the cosmetic of the present invention, even as a silicone-free cosmetic, exhibits significantly improved powder dispersibility and stability, particularly stability against vibration.

In addition to the above-mentioned components, the cosmetic composition of the present invention may contain other optional components that are typically used in cosmetics, pharmaceuticals, and other skin topical preparations, as necessary, within the scope of not impairing the purpose and effects of the present invention. Examples of other optional components include powders other than the components (A) and (C), surfactants, polymeric compounds, chelating agents, lower alcohols, polyhydric alcohols, pH adjusters, antioxidants, fragrances, preservatives, disinfectants, various drugs, and the like. However, the components are not limited to these examples.

The cosmetic composition of the present invention can be produced according to a conventional method, and can be made into a formulation such as a liquid, emulsion, paste, cream, gel, or solid.
The cosmetic of the present invention can be provided as makeup cosmetics such as a makeup base, foundation, concealer, blusher, eye shadow, mascara, eyeliner, eyebrow, overcoat agent, lipstick, etc.; or skin care cosmetics such as a sunscreen, but is particularly suitable as a makeup cosmetic, in particular a makeup base and liquid foundation.

The present invention will be described in more detail below with reference to examples, but the present invention is in no way limited by these. Unless otherwise specified, the blending amount is indicated as mass % relative to the system in which the component is blended. Before describing each example in detail, the evaluation method used will be explained.

1. Evaluation of powder dispersibility immediately after preparation Immediately after preparation, the appearance of the sample was visually observed, and the powder dispersibility was evaluated based on the following criteria: The fewer color stripes, the more uniformly the powder was dispersed.
A: No color streaks are observed.
B: Slight color streaks were observed, but not to the extent that would cause problems in use.
C: Color stripes are clearly observed.
D: Color stripes are observed, and the product is unsuitable for use as a cosmetic.

2. Evaluation of vibration stability 30 ml of the prepared sample was placed in a resin tube and subjected to vibration at 10 Hz or more for 30 minutes. After leaving the sample to stand, the state of emulsion separation and powder aggregation of the sample were visually observed and evaluated based on the following criteria.
A: No emulsion destruction or powder aggregation is observed.
B: Emulsion destruction or powder aggregation is hardly observed.
C: Emulsion destruction or powder aggregation is observed.
D: Emulsion destruction and powder aggregation are severely observed.

3. Evaluation of stability over time A screw tube (50 ml) was filled with a sample and allowed to stand for 2 weeks in a thermostatic bath at 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, and the stability was evaluated based on the following criteria.
A: There is no change in viscosity, and there are no problems with the emulsion particles or appearance.
B: Slight changes in viscosity and in emulsion particles and appearance were observed, but not to the extent that would cause problems in use.
C: Changes in viscosity, emulsified particles, and appearance are observed.
D: Changes in viscosity, emulsion particles, and appearance were observed, and the product was not suitable for use as a cosmetic.

Oil-in-water emulsion cosmetics having the compositions shown in the table on the next page were prepared by standard methods. The stability and powder dispersibility of the prepared samples were evaluated according to the evaluation methods described above. The results are shown in the table.

*1: ASL-1 TiO2 CR-50 (manufactured by Daito Kasei Kogyo Co., Ltd.)
*2: ASL-Yellow LL-100P (manufactured by Daito Kasei Kogyo Co., Ltd.)
*3: ASL-Red R516P (manufactured by Daito Kasei Kogyo Co., Ltd.)
*4: ASI TiO2 CR-50 (manufactured by Daito Kasei Kogyo Co., Ltd.)
*5: ASI-Yellow LL-100P (manufactured by Daito Kasei Kogyo Co., Ltd.)
*6: ASI-Red R516P (manufactured by Daito Kasei Kogyo Co., Ltd.)
*7: NHS-Titanium CR-50 (manufactured by Miyoshi Chemical Industry Co., Ltd.)
*8: NHS-Yellow LL-100P (manufactured by Miyoshi Chemical Industry Co., Ltd.)
*9: NHS-Red R516PS (manufactured by Miyoshi Chemical Industry Co., Ltd.)
*10: NAI-Titanium CR-50 (manufactured by Miyoshi Chemical Industry Co., Ltd.)
*11: NAI-Yellow LL-100P (manufactured by Miyoshi Chemical Industry Co., Ltd.)
*12: NAI-Red R516PS (manufactured by Miyoshi Chemical Industry Co., Ltd.)
*13: LL TiO2 CR-50 (manufactured by Daito Kasei Kogyo Co., Ltd.)
*14: LL-Yellow LL-100P (manufactured by Daito Kasei Kogyo Co., Ltd.)
*15: LL-Red R516P (manufactured by Daito Kasei Kogyo Co., Ltd.)
*16: MI-Titanium CR-50 (manufactured by Miyoshi Chemical Industry Co., Ltd.)
*17: MI-Yellow LL-100P (manufactured by Miyoshi Chemical Industry Co., Ltd.)
*18: MI-Red R516PS (manufactured by Miyoshi Chemical Industry Co., Ltd.)
*19: ST-485SA (manufactured by Titanium Industries)

As shown in the table, the cosmetic preparation of Comparative Example 1, which did not contain the water-soluble alkyl-substituted polysaccharide derivative (D) of the present invention, could not be emulsified. Furthermore, the cosmetic preparations of Comparative Examples 2 to 6, which contained pigments that had been subjected to hydrophobic treatment using a treatment agent containing disodium stearoyl glutamate, which is a condensate of stearic acid having 18 carbon atoms and glutamic acid (NHS treatment, NAI treatment), a treatment agent in which the acylated amino acid is lysine (LL treatment), a fatty acid soap treatment agent (MI treatment), or a silicone treatment agent (EP1 treatment), showed color stripes immediately after preparation, and after the vibration test, significant emulsion destruction and powder aggregation were observed, and the stability over time was also poor.
On the other hand, the cosmetics of Examples 1 and 2, which contain the components (A) to (D) of the present invention, showed good powder dispersibility immediately after preparation, and were also excellent in both vibration stability and stability over time.
It should be noted that the cosmetic of Comparative Example 5, which contains a pigment that has been subjected to a hydrophobic treatment using a fatty acid soap treatment agent (MI treatment), corresponds to the cosmetic of the invention of Patent Document 1, but it was shown that the cosmetic of the present invention has improved powder dispersibility and stability over time compared to the cosmetic of the invention of Patent Document 1.

Claims (4)

(A) a pigment that has been surface-treated with a surface treatment agent containing glutamic acid or aspartic acid acylated with a saturated fatty acid having 8 to 14 carbon atoms or a salt thereof;
(B) oil,
(C) a hydrophobic ultraviolet scattering agent, and (D) a water-soluble alkyl-substituted polysaccharide derivative,
The blending amount of the ultraviolet absorber is less than 1 mass% based on the total amount of the cosmetic,
The oil-in-water emulsion cosmetic preparation contains no silicone compound , and the components (A) and (C) are dispersed in an oil phase. The oil-in-water emulsion cosmetic according to claim 1, wherein the acylated amino acid is sodium lauroyl glutamate or sodium lauroyl aspartate. The oil-in-water emulsion cosmetic according to claim 1 or 2, further comprising (E) a water-soluble thickener. The oil-in-water emulsion cosmetic according to any one of claims 1 to 3, wherein the proportion of polar oil in the oil component (B) is 40% or more by mass.