Oil-in-water emulsified cosmetic

Abstract

To provide an oil-in-water emulsified cosmetic that has no undissolved oily components to yield a homogeneous cosmetic, exhibits superior storage stability, and delivers superior compatibility with the skin upon application, leaving a moist feeling on the skin post-application.SOLUTION: An oil-in-water emulsified cosmetic contains the following components (A), (B), (C), (D), and (E): (A) natural-type sphingosine; (B) a fatty acid having 12 to 22 carbon atoms; (C) an acidic compound selected from inorganic acids and organic acids having 5 or fewer carbon atoms; (D) an oily agent in liquid or paste form at 25°C; and (E) water. The molar ratio (A) / (B) of component (A) to component (B) is 1 or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an oil-in-water type emulsified cosmetic.

Background Art

[0002] Since sphingosine has an effect of improving skin problems such as skin aging and wrinkles, cosmetics containing the same have been studied. For example, Patent Document 1 describes that an oil-in-water type emulsified composition containing an ester oil that is liquid at 25°C, sphingosines, an acidic compound, cholesterol or phytosterol is excellent in emulsification stability, appearance, and usability. Patent Document 2 describes that a topical skin preparation containing sphingosines, an acidic compound, ceramides, and a fatty acid is excellent in storage stability and usability. Patent Document 3 describes that a vesicle composition containing a specific organic acid, sphingosines, and water and having a pH of 2 to 11 is excellent in stability against pH change and storage stability.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, there has been an increasing trend towards natural products, and many natural-derived raw materials are used in cosmetics. Sphingosines include natural and pseudo types. In particular, natural sphingosine has low solubility in oil agents, is difficult to formulate into cosmetics, and has problems in storage stability.

Means for Solving the Problem

[0005] The present inventor has found that by combining natural sphingosine with a specific fatty acid at a specific ratio and using an acidic compound, an oil agent, and water, an oil-in-water type emulsified cosmetic can be obtained that has no remaining undissolved oily components, no separation or precipitation of crystals even after long-term storage, excellent storage stability, good skin compatibility when applied to the skin, and a moist feeling on the skin after application.

[0006] The present invention relates to the following components (A), (B), (C), (D), and (E): (A) Natural sphingosine, (B) A fatty acid having 12 to 22 carbon atoms, (C) An acidic compound selected from inorganic acids and organic acids having 5 or fewer carbon atoms, (D) An oil agent that is liquid or pasty at 25°C, (E) Water and relates to an oil-in-water type emulsified cosmetic containing the same, wherein the molar ratio (A) / (B) of component (A) to component (B) is 1 or more.

Effects of the Invention

[0007] The oil-in-water type emulsified cosmetic of the present invention has no remaining undissolved oily components, a uniform cosmetic can be obtained, no separation or precipitation of crystals even after long-term storage, excellent storage stability, good skin compatibility when applied to the skin, and a moist feeling on the skin after application.

Modes for Carrying Out the Invention

[0008] Component (A) used in the present invention is natural sphingosine, and any one can be used as long as it is used in ordinary cosmetics. For example, sphingosine (i), dihydrosphingosine (ii), phytosphingosine (iii), dehydrosphingosine (iv), dehydrophytosphingosine (v), sphingadienine (vi), etc. can be mentioned. The numbers at the end of the compound names indicate that the structural formulas of the compounds are the following formulas (i) to (vi). Among these, sphingosine (i), dihydrosphingosine (ii), phytosphingosine (iii), dehydrosphingosine (iv), and dehydrophytosphingosine (v) are preferred, sphingosine and phytosphingosine are more preferred, and phytosphingosine is even more preferred.

[0009]

Chemical formula

[0010] Component (A) can be used alone or in combination of two or more. From the viewpoints of suppressing separation and precipitation of crystals even after long-term storage and improving storage stability, and improving the moist feeling of the skin after application, the content is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass, even more preferably 0.1 to 3% by mass, and still more preferably 0.7 to 2% by mass in the total composition.

[0011] Component (B) is a fatty acid having 12 to 22 carbon atoms. Specifically, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, etc. may be mentioned. Among these, from the viewpoint of reducing the undissolved residue of the oily component and obtaining a uniform cosmetic, the carbon number of the fatty acid is preferably 14 to 22, more preferably 16 to 20, and even more preferably 18. Further, component (B) preferably contains one or more selected from myristic acid, palmitic acid, stearic acid, and behenic acid, more preferably contains one or more selected from stearic acid and palmitic acid, and even more preferably contains stearic acid.

[0012] Component (B) can be used alone or in combination of two or more. From the viewpoints of reducing the undissolved residue of the oily component and obtaining a uniform cosmetic, suppressing separation and precipitation of crystals even after long-term storage and improving storage stability, improving skin affinity when applied to the skin, and improving the moist feeling of the skin after application, the content is preferably 0.001 to 10% by mass, more preferably 0.01 to 4% by mass, still more preferably 0.02 to 2% by mass, even more preferably 0.1 to 1% by mass, and particularly preferably 0.38 to 0.53% by mass in the total composition.

[0013] In the present invention, from the viewpoints of reducing the undissolved residue of the oily component and obtaining a uniform cosmetic, suppressing separation and precipitation of crystals even after long-term storage and improving storage stability, improving skin affinity when applied to the skin, and improving the moist feeling of the skin after application, the molar ratio (A) / (B) of component (A) to component (B) is 1 or more, preferably 1 to 17, more preferably 1.2 to 10, and still more preferably 1.7 to 5.

[0014] Component (C) is an acidic compound selected from inorganic acids and organic acids having 5 or less carbon atoms. Examples of the inorganic acid include hydrochloric acid, nitric acid, nitrous acid, sulfuric acid, sulfurous acid, phosphoric acid, phosphonic acid, and phosphinic acid. Among these, from the viewpoint of suppressing separation and precipitation of crystals even after long-term storage and improving storage stability, it is preferable to contain one or more selected from hydrochloric acid and phosphoric acid, and more preferably contain hydrochloric acid.

[0015] Examples of organic acids having 5 or fewer carbon atoms include monocarboxylic acids such as acetic acid, propionic acid, and butyric acid; dicarboxylic acids such as succinic acid, phthalic acid, fumaric acid, oxalic acid, malonic acid, and glutaric acid; oxycarboxylic acids such as glycolic acid, citric acid, lactic acid, pyruvic acid, malic acid, and tartaric acid; and acidic amino acids such as glutamic acid and aspartic acid. Among these, from the viewpoint of suppressing separation and precipitation of crystals and improving storage stability even after long-term storage, it is preferable to contain at least one or two or more selected from monocarboxylic acids, oxycarboxylic acids, and acidic amino acids, more preferably to contain one or more selected from oxycarboxylic acids and acidic amino acids, even more preferably to contain one or two or more selected from lactic acid, glutamic acid, and aspartic acid, and even more preferably to contain glutamic acid.

[0016] Component (C) preferably contains one or more selected from hydrochloric acid and organic acids having 5 or fewer carbon atoms from the viewpoint of suppressing separation and precipitation of crystals and improving storage stability even after long-term storage, more preferably contains an organic acid having 5 or fewer carbon atoms, even more preferably contains one or more selected from oxycarboxylic acids and acidic amino acids, even more preferably contains one or two or more selected from lactic acid, glutamic acid, and aspartic acid, even more preferably contains one or more selected from lactic acid and glutamic acid, and even more preferably contains glutamic acid.

[0017] Component (C) can be used alone or in combination of two or more. From the viewpoint of suppressing separation and precipitation of crystals and improving storage stability even after long-term storage, the content is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass, even more preferably 0.05 to 2% by mass, and even more preferably 0.1 to 1% by mass in the total composition.

[0018] Component (D) is an oily agent that is liquid or paste-like at 25°C. Here, being liquid at 25°C means that the viscosity at 25°C is 10,000 mPa·s or less. The viscosity is measured with a B-type viscometer (VISCOMETER TVB-10, manufactured by Toki Sangyo Co., Ltd.), rotor No. 4, at 12 rpm for 1 minute. Being paste-like at 25°C means that the viscosity at 25°C is greater than 10,000 mPa·s, and it exhibits a semi-solid state. Those that are completely solidified (including powdery and flaky) at 25°C are not included in component (D) of the present invention. Also, component (B) is not included. Such liquid oils are not limited as long as they are commonly used in cosmetics, and examples include hydrocarbon oils, ester oils, ether oils, silicone oils, and the like. More specifically, examples of hydrocarbon oils include liquid paraffin, light isoparaffin, liquid isoparaffin, squalane, squalene, α-olefin oligomers, and the like. The hydrocarbon oil preferably contains one or more selected from squalane, liquid paraffin, liquid isoparaffin, and light liquid isoparaffin, more preferably contains one or more selected from squalane, liquid paraffin, and liquid isoparaffin, still more preferably contains one or more selected from squalane and liquid isoparaffin, and even more preferably contains squalane.

[0019] Examples of ester oils include monoester oils, diester oils, and triester oils. Examples of monoester oils include monoesters of aliphatic or aromatic monocarboxylic acids or dicarboxylic acids having 2 to 24 carbon atoms, and monoesters of trivalent alcohols and monofatty acids. Specific examples include cetyl 2-ethylhexanoate, cetyl octanoate, isononyl isononanoate, isotridecyl isononanoate, hexyl laurate, isopropyl myristate, octyldodecyl myristate, 2-hexyldecyl myristate, isopropyl palmitate, octyl palmitate, isocetyl stearate, isostearyl isostearate, octyl methoxycinnamate, 2-ethylhexyl hydroxystearate, alkyl benzoate (C12 - C15), and the like. As the monoester oil, it preferably contains one or more selected from isononyl isononanoate, isotridecyl isononanoate, and octyldodecyl myristate, and more preferably contains one or more selected from isotridecyl isononanoate and octyldodecyl myristate.

[0020] Examples of the diester oil include diesters of dicarboxylic acids having 3 to 18 carbon atoms, di-fatty acid esters of polyhydric alcohols, etc. Specific examples include propylene glycol dicaprylate, neopentyl glycol dicaprylate, glyceryl diisostearate, polyglyceryl diisostearate, glyceryl monoisostearate monomyristate, di-2-ethylhexyl succinate, diisopropyl sebacate, diisostearyl malate, neopentyl glycol di-2-ethylhexanoate, diisobutyl adipate, diisopropyl adipate, diethyl sebacate, di-2-ethylhexyl sebacate, diisopropyl sebacate, dicaprylyl carbonate, etc. The diester oil preferably contains neopentyl glycol dicaprylate.

[0021] Examples of the triester oil include tri-fatty acid esters of polyhydric alcohols having 3 or more valences. Specifically, glyceryl tri(caprylate / caprate), glyceryl tri-2-ethylhexanoate, glyceryl triisostearate, and furthermore, vegetable oils such as olive oil, jojoba oil, macadamia nut oil, meadowfoam oil, castor oil, safflower oil, sunflower oil, avocado oil, canola oil, sesame oil, rice germ oil, rice bran oil, evening primrose oil, almond oil, argania spinosa kernel oil, grape seed oil, hazelnut oil, rose hip oil, persic oil, camellia oil, etc. As the triester oil, it is preferably contains one or more selected from tri(caprylic / capric acid) glycerin, tri-2-ethylhexanoic acid glycerin, and vegetable oils, more preferably contains one or more selected from tri(caprylic / capric acid) glycerin, tri-2-ethylhexanoic acid glycerin, olive oil, jojoba oil, and meadowfoam oil, still more preferably contains one or more selected from tri(caprylic / capric acid) glycerin and olive oil, and even more preferably contains olive oil.

[0022] As the ester oil, it is preferably contains one or more selected from diester oils and triester oils, and more preferably contains a triester oil.

[0023] Examples of the ether oil include dialkyl ethers, specifically, dihexyl ether, dicaprylyl ether, cetyl-1,3-dimethylbutyl ether, and the like.

[0024] Examples of the silicone oil include volatile and non-volatile linear dimethylpolysiloxanes such as dimethylpolysiloxane (1 cs), dimethylpolysiloxane (1.5 cs), dimethylpolysiloxane (2 cs), dimethylpolysiloxane (6 cs), dimethylpolysiloxane (50 cs); branched siloxanes such as methyltrimethicone, tris(trimethylsilyl)methylsilane, tetrakis(trimethylsilyl)silane; cyclic dimethylsiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, crosslinked methylpolysiloxane, network methylpolysiloxane, dimethylpolysiloxane, methyltrimethicone, dimethylcyclopolysiloxane, methylphenylpolysiloxanes such as diphenylsiloxyphenyltrimethicone, and higher alcohol-modified organopolysiloxanes. As the silicone oil, it is preferably contains one or two or more selected from linear dimethylpolysiloxanes and branched siloxanes, more preferably contains a linear dimethylpolysiloxane, and still more preferably contains a non-volatile linear dimethylpolysiloxane.

[0025] Examples of the paste-like oil agent at 25°C include hydrocarbon oils, ester oils, sterol derivatives, dimer acid derivatives, and the like. Specifically, examples of the hydrocarbon include petrolatum. Examples of the ester oil include hydrogenated castor oil isostearate, glyceryl tri(caprylate / caprate / myristate / stearate), dipentaerythritol hexaoxystearate, and further vegetable oils such as shea butter and mango seed butter.

[0026] Examples of the sterol derivative include sterol esters. Specifically, examples include cholesteryl isostearate, cholesteryl hydroxystearate, cholesteryl macadamia nut oil fatty acid, di(cholesteryl / octyldodecyl) N-lauroyl-L-glutamate, di(cholesteryl / behenyl / octyldodecyl) N-lauroyl-L-glutamate, phytosteryl macadamia nut fatty acid, di(phytosteryl / 2-octyldodecyl) N-lauroyl-L-glutamate, di(phytosteryl / behenyl / 2-octyldodecyl) N-lauroyl-L-glutamate, phytosteryl isostearate, phytosteryl oleate, and the like. As the sterol ester derivative, it preferably contains one or more selected from cholesteryl isostearate, phytosteryl macadamia nut oil fatty acid, di(cholesteryl / octyldodecyl) N-lauroyl-L-glutamate, di(phytosteryl / 2-octyldodecyl) N-lauroyl-L-glutamate, and di(phytosteryl / behenyl / 2-octyldodecyl) N-lauroyl-L-glutamate, and more preferably contains phytosteryl macadamia nut oil fatty acid. Examples of the dimer acid derivative include di(phytosteryl / isostearyl / cetyl / stearyl / behenyl) dilinoleate.

[0027] As the oil agent of component (D), from the viewpoint of improving the moist feeling of the skin after application, it preferably contains one or more selected from hydrocarbon oils, ester oils, ether oils that are liquid at 25°C, hydrocarbon oils that are paste-like at 25°C, sterol derivatives, and dimer acid derivatives. More preferably, it contains one or more selected from hydrocarbon oils, ester oils that are liquid at 25°C, hydrocarbon oils that are paste-like at 25°C, sterol derivatives, and dimer acid derivatives. Even more preferably, it contains one or more selected from squalane, liquid isoparaffin, isononyl isononanoate, isotridecyl isononanoate, octyldodecyl myristate, propylene glycol dicaprylate, neopentyl glycol dicaprylate, tri(caprylic / capric acid) glycerin, tri(2-ethylhexanoic acid) glycerin, olive oil, jojoba oil, meadowfoam oil, shea butter, mango seed butter, petrolatum, cholesteryl isostearate, phytosteryl macadamia nut oil fatty acid, di(phytosteryl / isostearyl / cetyl / stearyl / behenyl) dilinoleate. Even more preferably, it contains one or more selected from squalane, propylene glycol dicaprylate, tri(caprylic / capric acid) glycerin, tri(2-ethylhexanoic acid) glycerin, olive oil, jojoba oil, meadowfoam oil, petrolatum, phytosteryl macadamia nut oil fatty acid. Most preferably, it contains one or more selected from squalane and olive oil.

[0028] Component (D) can be used in combination of one or more. From the viewpoints of reducing the undissolved residue of the oily component and obtaining a uniform cosmetic, suppressing separation and crystal precipitation even after long-term storage and improving storage stability, improving skin affinity when applied to the skin, and improving the moist feeling of the skin after application, the content is preferably 10 to 60% by mass in the total composition, more preferably 15 to 50% by mass, and even more preferably 25 to 35% by mass.

[0029] In the present invention, the mass ratio (A) / (D) of component (A) to component (D) is preferably from 0.00002 to 1, more preferably from 0.0002 to 0.3, still more preferably from 0.003 to 0.12, even more preferably from 0.01 to 0.08, and even more preferably from 0.028 to 0.04, from the viewpoints of reducing the undissolved residue of the oily component and obtaining a uniform cosmetic, suppressing separation and precipitation of crystals even after long-term storage and improving storage stability, improving skin affinity when applied to the skin, and improving the moist feeling of the skin after application.

[0030] The water content of component (E) is preferably 10 to 90% by mass, more preferably 30 to 80% by mass, and still more preferably 40 to 70% by mass in the total composition, from the viewpoint of suppressing separation and precipitation of crystals even after long-term storage and improving storage stability.

[0031] In the present invention, the mass ratio (D) / (E) of component (D) to component (E) is preferably from 0.1 to 6, more preferably from 0.2 to 2, and still more preferably from 0.3 to 1, from the viewpoint of improving the moist feeling of the skin after application.

[0032] The oil-in-water type emulsified cosmetic of the present invention may further contain an oily agent that is solid at 25°C other than components (A) and (B), and separation and precipitation of crystals can be suppressed even after long-term storage, and storage stability can be further improved. Here, being solid at 25°C means a solid state (including powdery and flaky) that is completely solidified at 25°C, and is distinguished from component (D). Such a solid oily agent is not limited as long as it is usually used in cosmetics. For example, aliphatic alcohols, cholesterol derivatives, ceramides, phospholipids, hydrocarbon oils, ester oils, etc. can be used. Note that the cholesterol derivatives do not include the sterol derivatives of component (D).

[0033] Examples of the aliphatic alcohol include aliphatic alcohols having 12 to 30 carbon atoms such as cetyl alcohol, stearyl alcohol, behenyl alcohol, batyl alcohol, chimyl alcohol, etc. From the viewpoint of suppressing separation and precipitation of crystals and improving storage stability even after long-term storage, it preferably contains one or more selected from cetyl alcohol, stearyl alcohol, and batyl alcohol, and more preferably contains one or more selected from cetyl alcohol and stearyl alcohol.

[0034] Examples of the cholesterol include animal sterols such as cholesterol, cholestanol, lanosterol, seligosterol, dehydrocholesterol, coprostanol, etc., plant sterols such as phytosterol, β-sitosterol, stigmasterol, campesterol, ergosterol, etc., and microorganism-derived sterols such as mycosterol, thymosterol, etc. From the viewpoint of suppressing separation and precipitation of crystals and improving storage stability even after long-term storage, it preferably contains one or more selected from cholesterol and phytosterol.

[0035] Examples of the ceramide include natural ceramides such as ceramide 1, 2, 3, 4, 5, 6, 7, etc., and ceramide-like substances described in JP-A-62-228048, JP-A-63-216812, JP-A-63-227513, JP-A-64-29347, JP-A-64-31752, JP-A-8-319263, etc. Examples of the ceramide-like substance include compounds represented by the following general formulas (1) and (2) from the viewpoint of suppressing separation and precipitation of crystals and improving storage stability even after long-term storage.

[0036] [Chemical formula]

[0037] [In the formula, R 1b represents a hydrocarbon group having 10 to 26 carbon atoms, R 2b represents a hydrocarbon group having 9 to 25 carbon atoms, and X is -(CH2) n-(where n represents an integer from 2 to 6).

[0038] [Chemical Formula]

[0039] (In the formula, R 1 and R 2 each independently represent a hydrocarbon group which may be hydroxylated and has 1 to 40 carbon atoms, R 3 represents an alkylene group having 1 to 6 carbon atoms or a single bond, and R 4 represents a hydrogen atom, an alkoxy group having 1 to 12 carbon atoms, or a 2,3-dihydroxypropyloxy group. However, when R 3 is a single bond, R 4 is a hydrogen atom.)

[0040] In the general formulas (1) and (2) above, the hydrocarbon group is preferably an alkyl group or an alkenyl group. Examples of the compound of the general formula (1) include N-(hexadecyloxyhydroxypropyl)-N-hydroxyethylhexadecanamide, and examples of the compound of the general formula (2) include long-chain dibasic acid bis 3-methoxypropylamide.

[0041] From the viewpoint of suppressing separation and precipitation of crystals and improving storage stability even after long-term storage, ceramides preferably contain one or more selected from natural ceramides and the compounds represented by the general formulas (1) and (2), more preferably contain one or more selected from natural ceramides and the compounds represented by the general formula (1), still more preferably contain one or more selected from natural ceramides and N-(hexadecyloxyhydroxypropyl)-N-hydroxyethylhexadecanamide, and even more preferably contain N-(hexadecyloxyhydroxypropyl)-N-hydroxyethylhexadecanamide.

[0042] As for the phospholipid, from the viewpoint of suppressing separation and precipitation of crystals and improving storage stability even after long-term storage, the phosphatidylcholine content is preferably 60% by mass or more, more preferably 64% by mass or more, still more preferably 68% by mass or more, and even more preferably 70% by mass or more. Examples of phospholipid components other than phosphatidylcholine include phosphatidic acid, phosphatidylserine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylglycerol and the like.

[0043] The phospholipid may be a natural product extracted and purified from animals and plants, a chemically synthesized product, or a product subjected to processing such as hydrogenation or hydroxylation treatment. As the natural product, from the viewpoint of suppressing separation and precipitation of crystals and improving storage stability even after long-term storage, a phospholipid that is an extract from soybeans or egg yolk or a purified product thereof is preferable, and a hydrogenated or hydroxylated phospholipid is more preferable. Specifically, one or more selected from hydrogenated soy lecithin and hydrogenated egg yolk lecithin are preferable, and hydrogenated soy lecithin is more preferable. Examples of the hydrocarbon oil include paraffin wax, microcrystalline wax, ceresin and the like. Examples of the ester oil include cetyl palmitate and the like.

[0044] Component (F) preferably contains one or more selected from aliphatic alcohols, sterols, ceramides, and phospholipids from the viewpoint of suppressing separation and precipitation of crystals and improving storage stability even after long-term storage. More preferably, it contains one or more selected from cetyl alcohol, stearyl alcohol, cholesterol, phytosterol, natural ceramide, N-(hexadecyloxyhydroxypropyl)-N-hydroxyethylhexadecanamide, hydrogenated soy lecithin, and hydrogenated egg yolk lecithin. Even more preferably, it contains one or more selected from cetyl alcohol, stearyl alcohol, and N-(hexadecyloxyhydroxypropyl)-N-hydroxyethylhexadecanamide.

[0045] Component (F) can be used singly or in combination of two or more. From the viewpoint of suppressing separation and precipitation of crystals even after long-term storage and improving storage stability, the content is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, still more preferably 0.5 to 3% by mass, and even more preferably 1.7 to 2.5% by mass in the total composition.

[0046] The oil-in-water emulsified cosmetic of the present invention can further contain (G) a dihydric alcohol, which can reduce the undissolved residue of the oily component, obtain a more uniform cosmetic, and further improve the skin compatibility when applied to the skin. The dihydric alcohol of component (G) is a compound having two hydroxyl groups in the molecule, and any one can be used as long as it is used in ordinary cosmetics. Examples of such dihydric alcohols include polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,3-butylene glycol, 1,3-propanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol and the like. Among these, from the viewpoint of improving skin compatibility when applied to the skin, it preferably contains one or more selected from propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butylene glycol, 1,3-propanediol, 1,2-pentanediol, 1,2-hexanediol; more preferably contains one or more selected from dipropylene glycol, 1,3-butylene glycol, 1,3-propanediol, 1,2-pentanediol; still more preferably contains one or more selected from dipropylene glycol, 1,3-propanediol, 1,2-pentanediol; and even more preferably contains one or more selected from 1,3-propanediol, 1,2-pentanediol.

[0047] Component (G) can be used singly or in combination of two or more. From the viewpoints of reducing the undissolved residue of the oily component, obtaining a uniform cosmetic, improving the skin affinity when applied to the skin, and improving the moist feeling of the skin after application, the content is preferably 3 to 30% by mass, more preferably 5 to 20% by mass, still more preferably 7 to 15% by mass, and even more preferably 8 to 12% by mass in the total composition.

[0048] In the present invention, the mass ratio (G) / (E) of component (G) to component (E) is preferably 0.03 to 3, more preferably 0.06 to 1, still more preferably 0.1 to 0.5, even more preferably 0.15 to 0.35, and particularly preferably 0.16 to 0.19 from the viewpoints of reducing the undissolved residue of the oily component, obtaining a uniform cosmetic, suppressing separation and precipitation of crystals even after long-term storage, improving the storage stability, improving the skin affinity when applied to the skin, and improving the moist feeling of the skin after application.

[0049] The oil-in-water type emulsified cosmetic of the present invention may further contain a polyhydric alcohol having three or more hydroxyl groups. The polyhydric alcohol having three or more hydroxyl groups is a compound having three or more hydroxyl groups in the molecule, and any one can be used as long as it is used in ordinary cosmetics. Examples of the trihydric alcohol include glycerin and trimethylolpropane. Examples of the tetrahydric alcohol include diglycerin and erythritol. Examples of the polyhydric alcohol having five or more hydroxyl groups include polyglycerins such as triglycerin; saccharides and sugar alcohols such as glucose, maltose, maltitol, sucrose, xylitol, sorbitol, maltitol, polyoxyethylene methyl glucoside, polyoxyethylene ethyl glucoside, and polyoxyethylene propylene glucoside.

[0050] From the viewpoint of improving the moist feeling of the skin after application, the polyhydric alcohol having three or more hydroxyl groups preferably contains glycerin, diglycerin, sorbitol, and maltitol, and more preferably contains glycerin.

[0051] Polyhydric alcohols with a valency of 3 or higher can be used alone or in combination of two or more. From the viewpoint of improving the moist feeling of the skin after application, the content is preferably 1 to 30% by mass, more preferably 2 to 20% by mass, still more preferably 3 to 15% by mass, and even more preferably 4 to 10% by mass in the total composition.

[0052] From the viewpoint of suppressing separation and precipitation of crystals and improving storage stability, the water-in-oil emulsion cosmetic of the present invention preferably has a pH of 6.0 or less, more preferably 3.0 to 6.0, and still more preferably 4.0 to 5.5. The pH is measured using a pH meter (manufactured by HORIBA, model number F-72) at 25°C.

[0053] In addition to the above components, the water-in-oil emulsion cosmetic of the present invention can contain components usually used in cosmetics, such as surfactants, powders, antioxidants, fragrances, preservatives, blood circulation promoters, cooling agents, antiperspirants, bactericides, skin activators, cooling agents, colorants, etc.

[0054] The water-in-oil emulsion cosmetic of the present invention can be produced according to a usual method. For example, an oil phase in which an oily component containing components (A), (B), and (D) is heated and stirred to be uniformly dissolved is prepared, and an aqueous phase containing heated components (C) and (E) is added to the obtained oil phase and stirred. Then, it can be cooled to 25°C to produce a water-in-oil emulsion cosmetic.

[0055] The water-in-oil emulsion cosmetic of the present invention can be applied, for example, as makeup cosmetics such as makeup bases, foundations, concealers, blushes, eyeshadows, mascaras, eyeliners, eyebrows, overcoat agents, lipsticks; sunscreen cosmetics such as sunscreen lotions and sunscreen creams; skin care cosmetics such as skin care lotions, skin care creams, BB creams, and beauty essences. Among them, it is suitable as a skin care cosmetic.

Examples

[0056] Examples 1 to 13, Comparative Examples 1 to 3 Oil-in-water emulsified cosmetics having the compositions shown in Table 1 were produced, and the dissolution of the oil phase, pH, storage stability (presence or absence of separation), storage stability (presence or absence of crystals), skin compatibility, and skin moist feeling were evaluated. The results are shown together with Table 1.

[0057] (Manufacturing method) An oil phase in which components (A), (B), (D), (F) and other oily components were heated and stirred at 80°C or higher to be uniformly dissolved was prepared. To the obtained oil phase, an aqueous phase containing components (C), (E), (G) and other aqueous components heated to 80°C or higher was added and stirred. Then, it was cooled to 25°C to obtain an oil-in-water emulsified cosmetic.

[0058] (Evaluation method) (1) Dissolution of the oil phase: The oil phase components containing components (A), (B), and (D) were mixed, heated and stirred at 80°C for 30 minutes, and then it was visually confirmed whether there was any undissolved residue. ○: There is no undissolved residue. ×: There is undissolved residue and it is not dissolved.

[0059] (2) pH: For each cosmetic immediately after preparation, the pH was measured at 25°C using a desktop pH meter F-72 manufactured by HORIBA.

[0060] (3) Storage stability (presence or absence of separation): Each cosmetic was filled with 40 g in a 50 mL glass bottle and stored in a constant temperature bath at 50°C for 3 days. After storage, the glass bottle containing the cosmetic was taken out from the constant temperature bath at 50°C, allowed to stand at 25°C for 6 hours, and the appearance of the cosmetic was observed with the naked eye and evaluated according to the following criteria. When observing the cosmetic "from above", it was observed after removing the lid of the glass bottle. 4: There is no separation even when observing the glass container horizontally and from above. 3: When observing the glass container horizontally, no separation is visible, but when observing from above, there are slightly scattered oil droplets on the surface of the cosmetic. 2: When observing the glass container horizontally, there is separation and the separation is less than 1 mm. 1: When observing the glass container horizontally, there is a separation, and the separation is 1 mm or more.

[0061] (4) Storage stability (presence or absence of crystals): Each cosmetic was filled with 40 g into a 50 mL glass bottle and stored in a constant temperature bath at 50 °C for 3 days. After storage, the glass bottle containing the cosmetic was taken out from the constant temperature bath at 50 °C and left to stand at 25 °C for 6 hours. For the cosmetic, the presence or absence of crystal precipitation was observed with an optical microscope (20 times magnification) and evaluated according to the following criteria. 4: There is no crystal precipitation. 3: Slight crystal precipitation can be seen. 2: Obvious crystal precipitation can be seen in part. 1: Crystals are precipitated over the entire surface.

[0062] (5) Ease of skin adaptation: Three professional panelists took about 0.2 g of each cosmetic on the back of the hand and evaluated the ease of skin adaptation when it was kneaded with the fingers according to the following criteria. The results were shown as the total score of the three panelists. 5: Very easy to adapt to the skin. 4: Easy to adapt to the skin. 3: Slightly easy to adapt to the skin. 2: Not very easy to adapt to the skin. 1: Difficult to adapt to the skin.

[0063] (6) Moist feeling of the skin: Three professional panelists took about 0.2 g of each cosmetic on the back of the hand and evaluated the moist feeling of the skin after kneading it with the fingers according to the following criteria. The results were shown as the total score of the three panelists. 5: Very moist feeling. 4: Moist feeling. 3: Slightly moist feeling. 2: Not very moist feeling. 1: No moist feeling.

[0064]

Table 1

[0065] *1 Phytosphingosine (Molecular weight: 317.51): Phytosphingosine (manufactured by Evonik Operations GmbH), *2 Stearic acid (Molecular weight: 284.48): Luna c S-90V (manufactured by Kao Corporation), *3 Palmitic acid (Molecular weight: 256.4): Palmitic acid 98 (manufactured by Miyoshi Oil & Fat Co., Ltd.), *4 Glutamic acid: L-Glutamic acid (manufactured by Ajinomoto Foods Europe SAS), *5 Sugar squalane: Nikkol Sugar Squalane (manufactured by Nippon Surfactant Industry Co., Ltd.), *6 Olive oil: CroPure OL-LQ-(JP) (manufactured by Croda Japan Inc.), *7 Cetyl alcohol: Calcohol 6098 (manufactured by Kao Corporation), *8 Stearyl alcohol: Calcohol 8098 (manufactured by Kao Corporation), *9 (N-(Hexadecyloxyhydroxypropyl)-N-hydroxyethylhexadecanamide): Sphingolipid E (manufactured by Kao Corporation) *10 1,3-Propanediol: ZEMEA SELECT Propanediol (manufactured by Primient Covation LLC) *11 Dipropylene glycol: DPG-RF (manufactured by ADEKA Corporation) *12 1,2-Pentanediol: HYDROLITE 5 GREEN (manufactured by Symrise AG) *13 Glycerin: RG·Co·K (manufactured by NOF Corporation)

[0066] Formulation Examples 1 to 5 The water-in-oil type emulsified cosmetic having the composition shown in Table 2 is produced in the same manner as in Examples 1 to 13, has no undissolved oily components, shows no separation or crystal precipitation even after long-term storage, has excellent storage stability, has good skin compatibility when applied to the skin, and gives a moist feeling to the skin after application.

[0067] [Table 2]

Claims

**Claim 1** An oil-in-water type emulsified cosmetic containing the following components (A), (B), (C), (D) and (E): (A) Natural sphingosine, (B) A fatty acid having 12 to 22 carbon atoms, (C) An acidic compound selected from inorganic acids and organic acids having 5 or less carbon atoms, (D) An oil agent that is liquid or paste-like at 25°C, (E) Water wherein the molar ratio (A) / (B) of component (A) to component (B) is 1 or more. **Claim 2** The oil-in-water type emulsified cosmetic according to Claim 1, further containing (F) an oil agent that is solid at 25°C other than components (A) and (B). **Claim 3** The oil-in-water type emulsified cosmetic according to Claim 1 or 2, further containing (G) a dihydric alcohol. **Claim 4** The oil-in-water type emulsified cosmetic according to Claim 1 or 2, having a pH of less than 6. **Claim 5** The oil-in-water type emulsified cosmetic according to Claim 1 or 2, wherein the mass ratio (A) / (D) of component (A) to component (D) is 0.00002 to 1. **Claim 6** The oil-in-water type emulsified cosmetic according to Claim 1 or 2, wherein component (C) contains an organic acid having 5 or less carbon atoms.

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