Oil-in-water emulsion cosmetic

Abstract

The purpose of the present invention is to provide an oil-in-water type emulsion cosmetic which is capable of stably holding a vitamin A fatty acid ester even if both the vitamin A fatty acid ester and an ultraviolet absorber are blended, and which has excellent emulsion stability. The oil-in-water emulsion cosmetic according to the present invention comprises (A) a vitamin A fatty acid ester, (B) an ultraviolet absorber, (C) a nonionic surfactant, and (D) a hydrophilic thickener, and is characterized in that: the content of the vitamin A fatty acid ester (A) is 0.001-0.5 mass% relative to the total amount of the cosmetic; the ratio of the content of the nonionic surfactant (C) to the content of the hydrophilic thickener (D) is in the range of 0.4-0.9.

Description

Technical Field

[0001] The present invention relates to an oil-in-water emulsified cosmetic. More specifically, it relates to an oil-in-water emulsified cosmetic that can stably incorporate a vitamin A fatty acid ester in the presence of an ultraviolet absorber and also has excellent emulsification stability of the cosmetic. Background Art

[0002] Hitherto, vitamin A compounds (=retinols) typified by vitamin A and vitamin A acetate have been known as effective ingredients for preventing or treating skin keratosis, abnormal dryness, pigment deposition, etc. and for preventing or restoring skin aging, and have been widely used in cosmetics for treating acne, promoting skin renewal, etc.

[0003] However, vitamin A compounds are extremely unstable and easily deteriorate due to many factors such as light, air, heat, and metal ions. Therefore, it is difficult to stably incorporate vitamin A compounds into an oil-in-water emulsified cosmetic, and how to prevent the deterioration of vitamin A compounds and maintain their activity has become a problem.

[0004] As an attempt to improve the stability of vitamin A compounds in an oil-in-water emulsified cosmetic, for example, Patent Document 1 proposes to contain a vitamin A fatty acid ester having an oxidation stability superior to that of vitamin A, an oil-soluble antioxidant, an amphiphilic substance, and a hydrophilic nonionic surfactant at a specific mixing ratio.

[0005] However, when an ultraviolet absorber is further incorporated into an oil-in-water emulsified cosmetic containing such a vitamin A fatty acid ester, there is a tendency for the emulsified state of the cosmetic to become unstable. Protecting the skin, etc. from ultraviolet rays is one of the important subjects in skin care, body care, etc., and it is desired that an oil-in-water emulsified cosmetic containing vitamin A compounds also has a high ultraviolet protection effect.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Laid-Open No. 11-228377 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] An object of the present invention is to provide an oil-in-water emulsified cosmetic that contains both a vitamin A fatty acid ester and an ultraviolet absorber and has excellent stability of the vitamin A fatty acid ester and emulsification stability of the cosmetic.

[0011] Solutions for Solving the Problems

[0012] The inventor of the present invention has conducted in - depth research repeatedly to solve the above - mentioned problems. As a result, it has been found that by limiting the content of vitamin A fatty acid ester to a specific range and formulating a non - ionic surfactant and a hydrophilic thickener at a specific ratio, an oil - in - water type emulsified cosmetic that can stably maintain the vitamin A fatty acid ester even when both the vitamin A fatty acid ester and an ultraviolet absorber are formulated and has excellent emulsification stability of the cosmetic can be obtained, and the present invention has been completed.

[0013] That is, the gist of the present invention is an oil - in - water type emulsified cosmetic, which contains:

[0014] (A) Vitamin A fatty acid ester,

[0015] (B) Ultraviolet absorber,

[0016] (C) Non - ionic surfactant, and

[0017] (D) Hydrophilic thickener,

[0018] wherein the content of (A) vitamin A fatty acid ester is 0.001 - 0.5% by mass relative to the total amount of the cosmetic,

[0019] The ratio of the content of (C) non - ionic surfactant to the content of (D) hydrophilic thickener (hereinafter sometimes referred to as "C / D ratio") is in the range of 0.4 - 0.9.

[0020] Effects of the Invention

[0021] By forming the above - mentioned composition, the oil - in - water type emulsified cosmetic of the present invention can be sufficiently emulsified with a small amount of non - ionic surfactant, can maintain the stability of vitamin A fatty acid ester, and can prevent the reduction of emulsification stability even when an ultraviolet absorber is formulated.

[0022] Thus, an oil - in - water type emulsified cosmetic can be realized, which has both the effects such as anti - skin - aging brought by vitamin A fatty acid ester and the ultraviolet - defense effect brought by the ultraviolet absorber, and the effects are not easily deteriorated over time, and the emulsification stability is also excellent. Detailed Embodiments

[0023] The oil - in - water type emulsified cosmetic of the present invention is characterized in that it contains (A) vitamin A fatty acid ester, (B) ultraviolet absorber, (C) non - ionic surfactant, and (D) hydrophilic thickener under specified conditions. Hereinafter, each component constituting the oil - in - water type emulsified cosmetic of the present invention will be described in detail.

[0024] <(A) Vitamin A fatty acid ester>

[0025] (A) Vitamin A fatty acid esters used in the present invention include, for example: vitamin A acetate (retinol acetate), vitamin A palmitate (retinol palmitate), vitamin A propionate (retinol propionate), etc. One kind can be used alone, or two or more kinds can be used simultaneously. From the viewpoint of application to the skin, vitamin A acetate (retinol acetate) is particularly preferred.

[0026] (A) The compounding amount of vitamin A fatty acid ester is 0.001% by mass or more, more preferably 0.1% by mass or more, based on the total amount of the oil-in-water emulsified cosmetic, and is 0.5% by mass or less, more preferably 0.2% by mass or less. Therefore, as the compounding amount range, examples include: 0.001 - 0.5% by mass, 0.1 - 0.2% by mass, etc. If it is within this range, the anti-skin aging effect and the like possessed by (A) vitamin A fatty acid ester can be fully exerted.

[0027] <(B) UV absorber>

[0028] For the (B) UV absorber used in the present invention, there is no particular limitation as long as it is a substance that can be used in cosmetics.

[0029] Specific examples include: organic UV absorbers such as ethylhexyl methoxycinnamate, octocrylene, 2-hydroxy-4-methoxybenzophenone, benzylidene malonate polysiloxane, butyl methoxydibenzoylmethane, ethylhexyl triazone, diethylamino hydroxybenzoyl hexyl benzoate, bis-ethylhexyloxyphenol methoxyphenyl triazine, methylene bis-benzotriazolyl tetramethylbutylphenol, phenylbenzimidazole sulfonic acid, homosalate, ethylhexyl salicylate, etc.

[0030] (B) The compounding amount of the UV absorber is preferably 3% by mass or more, more preferably 5% by mass or more, based on the total amount of the oil-in-water emulsified cosmetic, and is preferably 15% by mass or less, more preferably 10% by mass or less. Therefore, as the compounding amount range, examples include: 3 - 15% by mass, 5 - 10% by mass, etc.

[0031] <(C) Nonionic surfactant>

[0032] Examples of the (C) nonionic surfactant used in the present invention include: polyoxyethylene (hereinafter sometimes abbreviated as POE) sorbitan fatty acid esters such as POE sorbitan monooleate; POE sorbitol fatty acid esters such as POE sorbitol monooleate; POE glycerol fatty acid esters such as POE glycerol monostearate and POE glycerol mono isostearate; POE fatty acid esters such as POE monooleate, POE distearate, and POE dioleate; POE alkyl ethers such as POE oleyl ether, POE stearyl ether, POE behenyl ether, POE cetyl ether, POE 2-octyldodecyl ether, POE 2-hexyldecyl ether, POE 2-heptylundecyl ether, POE 2-decyltetradecyl ether, POE 2-decylpentadecyl ether, and POE cholesteryl ether; POE alkylphenyl ethers such as POE octylphenyl ether and POE nonylphenyl ether; Pluronic type; POE·POP alkyl ethers such as POE·POP cetyl ether and POE·POP 2-decyltetradecyl ether; POE castor oil and other POE castor oil / hydrogenated castor oil derivatives; POE beeswax and other POE beeswax / lanolin derivatives; polyglycerol monoalkyl esters / monoalkyl ethers; sucrose fatty acid esters such as sucrose monooleate; silicone-based surfactants, etc.

[0033] Among them, POE alkyl ethers (the total number of moles of added POE is 20 to 30) such as POE(20) behenyl ether, POE(30) behenyl ether, POE(20) cetyl ether, POE(30) cetyl ether, POE(20) stearyl ether, and POE(20) oleyl ether are preferred; POE(20) behenyl ether (hereinafter sometimes referred to as "behenyl alcohol polyether-20") is particularly preferred. Examples of commercially available products include NIKKOL BB-20, BB-30, etc. (Nikko Chemicals Co., Ltd.).

[0034] The blending amount of the (C) nonionic surfactant is preferably 0.3% by mass or more, more preferably 0.5% by mass or more, based on the total amount of the oil-in-water emulsified cosmetic. In addition, it is preferably 1.2% by mass or less, more preferably 1% by mass or less. Therefore, examples of the blending amount range include 0.3 to 1.2% by mass and 0.5 to 1% by mass.

[0035] <(D) Hydrophilic thickener>

[0036] Examples of the (D) hydrophilic thickener used in the present invention include: plant-based polymers such as gum arabic, tragacanth gum, galactan, carob gum, guar gum, karaya gum, carrageenan, xanthan gum, pectin, agar, quince seeds (Cydonia oblongata), sodium alginate (brown algae extract); microbial-based polymers such as gellan gum, dextran, succinoglycan, pullulan; animal-based polymers such as collagen, casein, albumin, gelatin; starch-based polymers such as starch (rice, corn, potato, wheat), carboxymethyl starch, methyl hydroxypropyl starch; cellulose-based polymers such as hydrophobically modified alkyl cellulose, methyl cellulose, nitrocellulose, ethyl cellulose, methyl hydroxypropyl cellulose, hydroxyethyl cellulose, sodium cellulose sulfate, hydroxypropyl cellulose, sodium carboxymethyl cellulose, hydroxypropyl methyl cellulose stearoxy ether, microcrystalline cellulose, powdered cellulose; alginic acid-based polymers such as sodium alginate, propylene glycol alginate; vinyl-based polymers such as polyvinyl methyl ether, carboxyvinyl polymer; acrylic-based polymers such as polyoxyethylene-based polymers, polyoxyethylene-polyoxypropylene copolymer-based polymers, ethyl acrylate, polyacrylamide; inorganic water-soluble polymers such as polyethyleneimine, cationic polymer, bentonite, magnesium aluminum silicate, synthetic hectorite, saponite, silicon dioxide (silicic acid anhydride); PEG-240 / HDI copolymer bis-decyltetradeceth-20 ether, dimethylacrylamide / sodium acryloyldimethyltaurate cross-linked polymer, sodium acrylate / sodium acryloyldimethyltaurate copolymer, acrylate / steareth-20 methacrylate copolymer, ammonium acryloyldimethyltaurate / vinylpyrrolidone copolymer, etc.

[0037] Among them, hydroxypropyl methyl cellulose stearoxy ether and dimethylacrylamide / sodium acryloyldimethyltaurate cross-linked polymer are preferred.

[0038] The blending amount of the (D) hydrophilic thickener is preferably 0.3% by mass or more, more preferably 0.5% by mass or more, based on the total amount of the oil-in-water type emulsified cosmetic, and preferably 3.0% by mass or less, more preferably 2.0% by mass or less. Therefore, as the blending amount range, 0.3 - 3.0% by mass, 0.5 - 2.0% by mass, etc. can be cited.

[0039] <C / D ratio>

[0040] In the oil-in-water type emulsified cosmetic of the present invention, the ratio (C / D ratio) of the (C) nonionic surfactant to the content of the (D) hydrophilic thickener is 0.4 or more, more preferably 0.42 or more, and 0.9 or less, more preferably 0.85 or less. Therefore, as the C / D ratio range, 0.4 - 0.9, 0.42 - 0.85, etc. can be cited.

[0041] By adjusting the C / D ratio to this range, sufficiently excellent effects can be obtained in both aspects of (A) the stability of vitamin A fatty acid ester and the emulsion stability of the cosmetic.

[0042] <Optional Components>

[0043] In the oil-in-water emulsion cosmetic of the present invention, in addition to the above components (A) to (D), components commonly used in cosmetics can be incorporated within the range that does not interfere with the effects of the present invention. For example, in addition to oil components, aqueous solvents, humectants, medicaments, and antioxidants, chelating agents, preservatives, powders, edible flavors, colorants, pigments, etc. can be appropriately incorporated as needed.

[0044] The oil component is not particularly limited as long as it is a commonly used oil component in cosmetics, and examples include: hydrocarbon oils, higher alcohols, ester oils, fatty acids, fats and oils, waxes, etc.

[0045] Examples of hydrocarbon oils include: liquid paraffin, isocetane, isododecane, ozokerite, squalane, squalene, pristane, paraffin, isoparaffin, ceresin, petrolatum, microcrystalline wax, hydrogenated polyisobutene, olefin oligomers, volatile hydrocarbon oils (such as isododecane, isocetane, undecane, tridecane, etc.).

[0046] Examples of higher alcohols include: straight-chain alcohols such as lauryl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, myristyl alcohol, oleyl alcohol, cetearyl alcohol; branched-chain alcohols such as monostearyl glycerol ether (batyl alcohol), 2-decyltetradecanol, lanolin alcohol, cholesterol, phytosterol, hexyl dodecanol, isostearyl alcohol, octyldodecanol, etc.

[0047] As ester oils, for example, the following can be cited: isopropyl myristate, cetyl ethylhexanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyl decyl dimethyl octanoate, cetyl lactate, myristyl lactate, acetylated lanolin, isocetyl stearate, isocetyl isostearate, 12-cholesteryl hydroxystearate, ethylene glycol di-2-ethylhexanoate, dipentaerythritol fatty acid ester, N-alkyl diol monoisostearate, neopentyl glycol didecanoate, diisostearyl malate, glycerol di-2-heptylundecanoate, trimethylolpropane tris(2-ethylhexanoate), trimethylolpropane triisostearate, pentaerythritol tetra(ethylhexanoate), glycerol tri-2-ethylhexanoate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, glyceryl trimyristate, glycerol tri-2-heptylundecanoate, methyl ricinoleate, oleyl oleate, acetyl glyceride, 2-di(heptylundecyl) palmitate, diisobutyl adipate, di(2-heptylundecyl) adipate, ethyl laurate, di-2-ethylhexyl sebacate, isocetyl myristate, isocetyl palmitate, isocetyl adipate, diisopropyl sebacate, 2-ethylhexyl succinate, ethyl acetate, butyl acetate, amyl acetate, triethyl citrate, etc.

[0048] As fatty acids, for example, the following can be cited: oleic acid, isostearic acid, linoleic acid, linolenic acid, etc.

[0049] As oils and fats, for example, the following can be cited: Toxicodendron succedaneum wax, cocoa seed butter, hydrogenated castor oil, avocado oil, camellia oil, macadamia integrifolia oil, corn oil, olive fruit oil, rapeseed oil, sesame seed oil, peach kernel oil, wheat germ oil, Camellia kissi seed oil, castor oil, linseed oil, safflower oil, cottonseed oil, perilla oil, soybean oil, peanut oil, tea seed oil, torreya nucifera oil, rice bran oil, paulownia oil, Japanese tung oil, jojoba seed oil, germ oil, triglyceryl, glycerol tri(ethylhexanoate), glycerol triisopalmitate, etc.

[0050] As waxes, for example, the following can be cited: carnauba wax, beeswax, candelilla wax, jojoba wax, etc.

[0051] As aqueous solvents, for example, the following can be cited: water (purified water, ion-exchanged water, tap water, etc.), lower alcohols, or mixtures thereof.

[0052] As humectants, the following can be cited: polyoxyalkylene-polyoxyethylene copolymer dialkyl ether, 1,3-butanediol, polyethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, glycerol, diglycerol, xylitol, maltitol, maltose, D-mannitol, etc.

[0053] As agents, for example, the following can be cited: ascorbic acid (vitamin C), tranexamic acid, kojic acid, ellagic acid, arbutin, alkoxysalicylic acid, niacinamide, glycyrrhizic acid, tocopherol (vitamin E), and salts or derivatives thereof (for example, sodium L-ascorbate, magnesium L-ascorbate, L-ascorbic acid glucoside, 2-O-ethyl-L-ascorbic acid, 3-O-ethyl-L-ascorbic acid, sodium 4-methoxysalicylate, potassium 4-methoxysalicylate, dipotassium glycyrrhizate, stearyl glycyrrhizate, tocopheryl acetate, etc.).

[0054] As antioxidants, oil-soluble ones are preferred. For example, the following can be exemplified: butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), α,β,γ,δ-tocopherol, nordihydroguaiaretic acid, propyl gallate, fatty acid esters of vitamin C, sorbic acid, etc.

[0055] <Usage>

[0056] The form of the oil-in-water emulsified cosmetic of the present invention is not particularly limited, and any form such as lotion, milk lotion, cream, gel, essence (beauty liquid), etc., which have been used in cosmetics in the past, can be widely applied in any form.

[0057] Examples

[0058] Hereinafter, examples are given to further illustrate the present invention in detail, but the present invention is not limited to these embodiments at all. Unless otherwise specified, the blending amounts are expressed as mass % relative to the oil-in-water emulsified cosmetic. Before specifically describing each example, the evaluation method used will be described.

[0059] <Emulsification stability>

[0060] Each cosmetic (sample) was stored at 60 °C for 2 weeks, and separation or sedimentation was visually observed. The measurement results were evaluated according to the following criteria.

[0061] <Evaluation criteria>

[0062] A: Stable and no separation or sedimentation was observed

[0063] B: Separation or sedimentation was observed

[0064] <Stability of vitamin A fatty acid ester>

[0065] Each cosmetic (sample) contained in a glass screw tube was shielded from light with aluminum foil and stored at 50 °C for 1 month. Using high performance liquid chromatography, the residual rate (%) of vitamin A fatty acid ester in the cosmetic before storage and the cosmetic after storage for 1 month was determined. The measurement results were evaluated according to the following criteria.

[0066] High performance liquid chromatography was carried out under the following conditions.

[0067] Column: C18 column (manufactured by Shiseido Company, Limited)

[0068] Detection: UV 310 nm

[0069] Mobile phase: 72% methanol / 10% acetonitrile / 18% ion-exchanged water / 0.5% acetic acid

[0070] <Evaluation criteria>

[0071] A: The residual rate is 80% or more

[0072] B: The residual rate is less than 80%

[0073] Prepare the oil-in-water emulsified cosmetics of Reference Examples 1 to 2, Examples 1 to 3, and Comparative Examples 1 to 5 in Table 1 below, and evaluate them based on the above evaluation method and evaluation criteria. The evaluation results are shown together.

[0074] [Table 1]

[0075]

[0076] As shown in Table 1, when (B) the ultraviolet absorber is not formulated, the stability of (A) vitamin A fatty acid ester and the emulsification stability of the cosmetic are not problematic (Reference Examples 1 and 2), but when (B) the ultraviolet absorber is formulated, insufficient results are obtained in any evaluation item (Comparative Example 1).

[0077] In contrast, it was confirmed that by formulating (D) the hydrophilic thickener in such a manner that the ratio (C / D ratio) of the content of (C) the nonionic surfactant to (D) the hydrophilic thickener is in the range of 0.4 to 0.9, both the stability of (A) vitamin A fatty acid ester and the emulsification stability of the cosmetic are improved respectively (Examples 1 to 3). On the other hand, it is known that when the C / D ratio is not within the above range, not only the stability of (A) vitamin A fatty acid ester cannot be improved, but also the emulsification stability of the cosmetic is sometimes insufficient (Comparative Examples 2 to 5).

Claims

1. An oil-in-water emulsified cosmetic, which comprises: (A) Vitamin A fatty acid ester, (B) Ultraviolet absorber, (C) Nonionic surfactant, and (D) Hydrophilic thickener, Among them, The content of (A) vitamin A fatty acid ester is 0.001 to 0.5% by mass relative to the total amount of the cosmetic, The ratio of the content of (C) nonionic surfactant to the content of (D) hydrophilic thickener is in the range of 0.4 to 0.

9.

2. The oil-in-water emulsified cosmetic according to claim 1, wherein, (A) The vitamin A fatty acid ester is retinol acetate.

3. The oil-in-water emulsified cosmetic according to claim 1, wherein, The content of (A) vitamin A fatty acid ester is 0.1 to 0.2% by mass relative to the total amount of the cosmetic.

4. The oil-in-water emulsified cosmetic according to claim 1, wherein, The content of (B) ultraviolet absorber is 5 to 10% by mass relative to the total amount of the cosmetic.

5. The oil-in-water emulsified cosmetic according to claim 1, wherein, (C) The nonionic surfactant is one or more selected from POE alkyl ethers, and the total added mole number of POE is 20 to 30.

6. The oil-in-water emulsified cosmetic according to claim 1, wherein, (C) The nonionic surfactant is POE(20) behenyl ether, that is, behenyl alcohol polyether-20.

7. The oil-in-water type emulsified cosmetic according to claim 1, wherein, (D) The hydrophilic thickener is one or more selected from the group consisting of hydroxypropyl methylcellulose stearoxy ether and dimethylacrylamide / sodium acryloyldimethyltaurate cross-linked polymer.

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