Oil-in-water emulsion cosmetics

Abstract

The purpose of the present invention is to provide an oil-in-water type emulsion cosmetic which has such thixotropic properties that the cosmetic is in a creamy state with a moderate viscosity when being stored but shearing force given thereto during application abruptly drops the viscosity to change the creamy state to a flowable liquid state, and which smoothly spreads, easily agrees with the skin, and gives a fresh use feeling with no tackiness.　This oil-in-water type emulsion cosmetic comprises (A) a (meth)acrylic acid / alkyl (meth)acrylate / (meth)acrylic acid POE-monoalkyl-ether ester copolymer, (B) a nonionic surfactant, (C) a higher alcohol, and (D) an oil other than the higher alcohol (C), and is characterized in that at least some of the oil (D) is a polar oil (E) having an IOB of 0.1-0.5 and that the amounts (mass%) of (A) to (E) satisfy the requirements E / D≥0.65 and (E / D) / (A / (B+C))>7.4.

Description

[Technical Field]

[0001] The present invention relates to an oil-in-water emulsion cosmetic. More specifically, the present invention relates to an oil-in-water emulsion cosmetic that is creamy with a moderate viscosity, but has thixotropy, meaning that the viscosity rapidly decreases from a creamy state to a liquid state when shear force is applied upon application, and that spreads smoothly on the skin, blends in smoothly with the skin, and provides a refreshing, non-sticky feel when used. [Background technology]

[0002] For cosmetics applied to the skin, such as for skin care, the feel of use is an important factor. In particular, for cream cosmetics, it is desirable that they maintain an appropriate viscosity during storage, break down softly at the start of application, and remain smooth and spreadable without any squeaking until the end of application.

[0003] One of the factors that influence the feel of use is the method used to thicken cosmetics. Typical thickening methods for oil-in-water emulsion cosmetics are known to involve the use of water-soluble polymers and surfactants. Water-soluble polymers are used as thickeners for the aqueous phase, and in addition to the conventionally commonly used carbomers and polysaccharides, polysaccharides into which alkyl groups or ionic groups (sulfonic acid groups) have been introduced are also used to provide relatively good usability and stability when electrolytes are added (Patent Document 1). However, when any of these water-soluble polymers is used, adding an amount sufficient to maintain the stability of the cosmetic during long-term storage can cause sliminess, heavy spreading, and stickiness due to concentration during application.

[0004] Furthermore, examples of thickening using surfactants include a method of using a surfactant necessary for emulsifying the oil phase, either alone or in combination with other ingredients. For example, Patent Document 2 reports a method of preparing a cosmetic preparation that spreads easily by combining an acylmethyl taurine salt with behenyl alcohol to form an α-gel. However, in order to achieve sufficient hardness with α-gel, a relatively large amount of surfactant or higher alcohol is generally required, which can result in poor usability, such as heavy spreading or stickiness, when applied to the skin.

[0005] Therefore, it is technically not easy to achieve thixotropy that provides the above-mentioned feel when used in an oil-in-water emulsion cosmetic. On the other hand, in addition to realizing this feeling when used, in order to achieve a glossy finish, impart a rich feeling when used, or incorporate a large amount of an oil-soluble drug that dissolves in polar oil, it has been investigated to incorporate a high amount of polar oil into oil-in-water emulsion cosmetics.

[0006] However, when polar oil is incorporated at a high level, stickiness occurs, which can impair the fresh feel of the oil-in-water emulsion cosmetic. In particular, when polar oil is incorporated at a high level in an oil-in-water emulsion cosmetic that forms an α-gel, it is necessary to increase the amount of higher alcohol incorporated to stabilize the gel, which results in the cosmetic becoming hard and significantly impairing its spreadability upon application.

[0007] Thus, there is a demand for oil-in-water emulsion cosmetics that easily break down upon application, spread smoothly, and have excellent usability without stickiness. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 9-235301 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-6716 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in view of the above-mentioned circumstances, and aims to provide an oil-in-water emulsion cosmetic that is creamy with a moderate viscosity during storage, but has thixotropy, i.e., its viscosity rapidly decreases from a creamy state to a liquid state upon application, thereby exhibiting fluidity; spreads smoothly, blends smoothly into the skin, and provides a fresh, non-sticky feel when used. [Means for solving the problem]

[0010] As a result of intensive research conducted by the present inventors to solve the above-mentioned problems, they found that the above-mentioned problems can be solved by blending a (meth)acrylic acid / alkyl (meth)acrylate / (meth)acrylic acid POE monoalkyl ether ester copolymer, a nonionic surfactant, a higher alcohol, and an oil component including a polar oil, and adjusting the blending ratio of the components within a specific range, thereby completing the present invention.

[0011] That is, the present invention provides: (A) (meth)acrylic acid / alkyl (meth)acrylate / POE monoalkyl ether (meth)acrylate copolymer, (B) a nonionic surfactant, (C) higher alcohols, and (D) Oils other than the higher alcohols in (C) Including, (D) At least a portion of the oil component is (E) a polar oil having an IOB of 0.1 to 0.5, and The blending amounts (mass%) of (A) to (E) are as follows: E / D ≥ 0.65, and (E / D) / (A / (B+C))>7.4 The gist of the present invention is an oil-in-water emulsion cosmetic that satisfies the above requirements. [Effects of the Invention]

[0012] By adopting the above-described configuration, the oil-in-water emulsion cosmetic according to the present invention is able to achieve thixotropy, i.e., it remains in a creamy state with a moderate viscosity during storage, but the viscosity drops rapidly due to the shear force applied when spreading it with the fingers, and it easily breaks down from a creamy state to a liquid state, exhibiting fluidity. This allows the cosmetic to spread smoothly like a lotion, blend smoothly into the skin, and provide a refreshing feel without stickiness. DETAILED DESCRIPTION OF THE INVENTION

[0013] The oil-in-water emulsion cosmetic of the present invention is characterized by comprising, in a predetermined blending ratio, (A) a (meth)acrylic acid / alkyl (meth)acrylate / POE monoalkyl ether (meth)ester copolymer, (B) a nonionic surfactant, (C) a higher alcohol, and (D) an oil component, at least a portion of which is (E) a polar oil. The oil-in-water emulsion cosmetic of the present invention will be described in detail below.

[0014] <(A) (Meth)acrylic acid / alkyl (meth)acrylate / (meth)acrylic acid POE monoalkyl ether ester copolymer> The (A) (meth)acrylic acid / alkyl (meth)acrylate / POE monoalkyl ether (meth)acrylate copolymer blended in the oil-in-water emulsion cosmetic of the present invention is (a1) acrylic acid or methacrylic acid, (a2) alkyl acrylate or alkyl methacrylate, (a3) esters of acrylic acid or methacrylic acid with polyoxyethylene alkyl ethers; It is a copolymer of

[0015] Examples of component (A) include, as listed in the ICID (International Cosmetic Ingredient Dictionary), acrylates / ceteth-20 methacrylate copolymer, acrylates / steareth-20 methacrylate copolymer, acrylates / steareth-25 methacrylate copolymer, acrylates / steareth-50 methacrylate copolymer, acrylates / beheneth-25 methacrylate copolymer, acrylates / steareth-20 methacrylate crosspolymer, and ammonium acryloyldimethyltaurate / beheneth-25 methacrylate crosspolymer. Of these, acrylates / steareth-20 methacrylate copolymer (sometimes referred to as "(acrylates / steareth-20 methacrylate) copolymer") or acrylates / steareth-20 methacrylate crosspolymer is particularly preferred.

[0016] These are commercially available as aqueous dispersions (polymer emulsions), and preferred commercially available products include Accurin 22 (acrylates / steareth-20 methacrylate copolymer (Rohm and Haas)), Accurin 28 (acrylates / steareth-25 methacrylate copolymer (Rohm and Haas)), Accurin 88 (acrylates / steareth-20 methacrylate crosspolymer (Rohm and Haas)), and Aristoflex HMB (ammonium acryloyldimethyltaurate / beheneth-25 methacrylate crosspolymer (Clariant Production UK)).

[0017] A neutralizing agent can be added to component (A) to adjust its viscosity. There are no particular restrictions on the neutralizing agent, and inorganic bases such as sodium hydroxide and potassium hydroxide, and organic bases such as triethanolamine, isopropanolamine, and basic amino acids can be used.

[0018] The amount of component (A) in the cosmetic of the present invention is 0.1 to 1.0% by mass, preferably 0.12 to 0.8% by mass, and more preferably 0.15 to 0.5% by mass, based on the total amount of the cosmetic. If the amount is outside this range, the cosmetic may become sticky or difficult to spread, resulting in poor usability.

[0019] <(B) Nonionic surfactant> The nonionic surfactant (B) to be blended in the oil-in-water emulsion cosmetic of the present invention may be any surfactant that is commonly used in the cosmetic field. Specific examples include polyethylene glycol fatty acid esters, polyoxyethylene fatty acid glyceryl, polyoxyethylene behenyl ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene hydrogenated castor oil, polyoxyethylene-methylpolysiloxane copolymer, fatty acid polyoxyethylene sorbitan, polyoxyethylene alkyl ether, maltitol hydroxy fatty alkyl ether, alkylated polysaccharides, alkyl glucoside, sucrose fatty acid ester, polyoxyethylene hydrogenated castor oil glyceryl, polyoxyethylene sorbit fatty acid ester, polyoxyethylene-polyoxypropylene block copolymer, tetrapolyoxyethylene-tetrapolyoxypropylene-ethylenediamine condensate, polyoxyethylene-beeswax-lanolin derivative, alkanolamide, polyoxyethylene-propylene glycol fatty acid ester, polyoxyethylene-alkylamine, polyoxyethylene-fatty acid amide, alkylethoxydimethylamine oxide, and trioleyl phosphate.

[0020] Among these, preferred are hydrophilic nonionic surfactants having an HLB value in the range of 10 to 19, more preferably in the range of 12 to 18, and even more preferably in the range of 14 to 18. Examples thereof include polyoxyethylene (10 to 50 mol) behenyl ether such as Beheneth-20, polyoxyethylene (20 to 60 mol) sorbitan monostearate such as Polysorbate 60, polyoxyethylene (10 to 80 mol) fatty acid glyceryl such as PEG-60 glyceryl isostearate, polyoxyethylene (10 to 50 mol) polyoxypropylene (2 to 30 mol) cetyl ether such as PPG-8 ceteth-20, polyoxyethylene (20 to 100 mol) hydrogenated castor oil such as PEG-60 hydrogenated castor oil, and polyethylene glycol monostearate such as PEG-40 stearate. In particular, it is preferable that component (B) is one or more selected from polyoxyethylene (10 to 50 mol) behenyl ether, polyoxyethylene (20 to 60 mol) sorbitan monostearate, polyoxyethylene (10 to 50 mol) polyoxypropylene (2 to 30 mol) cetyl ether, and polyoxyethylene (20 to 100 mol) hydrogenated castor oil.

[0021] Preferred commercially available products of component (B) include, for example, NIKKOL BB-20 and BB-30 (Nikko Chemicals Co., Ltd.).

[0022] The blending amount of component (B) in the cosmetic of the present invention is 0.1 to 10 mass% of the total amount of the cosmetic, preferably 0.3 to 7 mass%, and more preferably 0.5 to 5 mass%. If component (B) is less than 0.1 mass%, the oily component cannot be stably emulsified, and if it exceeds 10 mass%, it may cause stickiness and a poor feel in use.

[0023] <(C) Higher Alcohol> The higher alcohol (C) blended in the oil-in-water emulsion cosmetic of the present invention is not particularly limited, as long as it is a higher alcohol having 14 to 22 carbon atoms that can be used in the field of cosmetics. Preferred examples of component (C) include myristyl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, and oleyl alcohol. Of these, the straight-chain unbranched cetyl alcohol, stearyl alcohol, and behenyl alcohol are particularly preferred.

[0024] Furthermore, in the present invention, it is preferable to use a mixture of two or more of the above-mentioned alcohols as component (C), and for example, a combination of stearyl alcohol and behenyl alcohol is particularly preferable.

[0025] The amount of component (C) in the cosmetic of the present invention is 0.1 to 10% by mass, preferably 0.3 to 7% by mass, and more preferably 1 to 3% by mass, based on the total amount of the cosmetic. If the amount of component (C) is less than 0.1% by mass, sufficient stability cannot be obtained, and if it exceeds 10% by mass, stickiness may occur and spreadability may be poor.

[0026] <(D) Oil content> The (D) oil component blended in the oil-in-water emulsion cosmetic of the present invention refers to any oil component other than the (C) higher alcohol, and essentially contains an (E) polar oil as part of the (D) oil component. Below, we will explain the (E) polar oil first, followed by the other (D) oil components.

[0027] <(E) Polar oil> The polar oil (E) blended in the oil-in-water emulsion cosmetic of the present invention has an IOB value in the range of 0.1 to 0.5, and more preferably in the range of 0.2 to 0.5. Here, the IOB value is the ratio of the inorganic value (IV) to the organic value (OV) in the organic conceptual diagram (Inorganic Organic Balance), and refers to "inorganic value (IV) / organic value (OV)". The organic conceptual diagram was proposed by Atsushi Fujita and is described in detail in "Pharmaceutical Bulletin," Vol. 2, pp. 163-173 (1954), "Chemical Domain," Vol. 11, pp. 719-725 (1957), and "Fragrance Journal," Vol. 50, pp. 79-82 (1981). The diagram considers methane (CH4) as the root of all organic compounds, and all other compounds as derivatives of methane. The diagram assigns a certain value to each of the carbon number, substituents, bond type (single, double, or triple bonds), and ring structure. These scores are added to determine the organic and inorganic values, which are then plotted on a diagram with the organic value on the X axis and the inorganic value on the Y axis. The organic conceptual diagram is also shown in "Organic Conceptual Diagram: Basics and Applications" (Yoshio Koda, Sankyo Publishing, 1984).

[0028] Specific examples of (E) polar oils include, but are not limited to, diisopropyl sebacate, pentaerythrityl tetraethylhexanoate, cetyl ethylhexanoate, di(phytosteryl / octyldodecyl) lauroyl glutamate, triisostearin, glyceryl diisostearate, triethylhexanoin, phytosteryl / behenyl dimer dilinoleate, phytosteryl / isostearyl / cetyl / stearyl / isostearyl / cetyl / stearyl / behenyl dimer dilinoleate, isopropyl palmitate, phytosteryl macadamia nut fatty acid, pentaerythrityl tetra(behenate / benzoate / ethylhexanoate), ethylhexyl palmitate, myristyl myristate, isopropyl myristate, tripropylene glycol dipivalate, and isodecyl neopentanoate.

[0029] In particular, the oil-in-water emulsion cosmetic according to the present invention preferably contains an oil-soluble ultraviolet absorber as part of the polar oil (E), since this allows the ultraviolet protection power of the ultraviolet absorber to be efficiently brought out. The oil-soluble UV absorber is not particularly limited as long as it satisfies the above IOB value, and examples thereof include methoxycinnamic acid derivatives, salicylic acid derivatives, benzoyl derivatives, camphor derivatives, para-aminobenzoic acid derivatives, triazine derivatives, benzophenone derivatives, and polysilicone-based compounds. Specific examples include 2-ethylhexyl paramethoxycinnamate, oxybenzone, 4-t-butyl-4'-methoxydibenzoylmethane, octyl triazone, bisethylhexyloxyphenol methoxyphenyl triazine, dioctyl butamido triazone, diethylaminohydroxybenzoyl hexyl benzoate, 2-cyano-3,3-diphenylacrylic acid-2'-ethylhexyl ester, polysilicone-15, octyl salicylate, homomenthyl salicylate, p-methylbenzylidene camphor, etc. These can be blended alone or in combination of two or more types as needed.

[0030] The blending amount of component (E) in the cosmetic of the present invention is 1 to 20% by mass, preferably 2 to 15% by mass, and more preferably 3 to 10% by mass, based on the total amount of the cosmetic. If the blending amount of (E) polar oil is less than 1% by mass, moisturizing effect cannot be obtained, and if it exceeds 20% by mass, stickiness may occur and spreadability may be poor.

[0031] <(D) Oils other than (E) Polar Oils> Of the oils contained in the (D) oil component, oils other than the (E) polar oil are not particularly limited, but examples thereof include fats and oils, waxes, hydrocarbon oils, higher fatty acids, silicones, and the like.

[0032] Examples of oils and fats include liquid oils and fats such as avocado oil, camellia oil, evening primrose oil, turtle oil, macadamia nut oil, corn oil, mink oil, olive oil, rapeseed oil, egg yolk oil, sesame oil, persic oil, wheat germ oil, camellia 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, and glycerin triisopalmitate; and solid oils and fats such as cacao butter, coconut oil, horse oil, hydrogenated coconut oil, palm oil, beef tallow, mutton tallow, hydrogenated beef tallow, palm kernel oil, lard, beef bone fat, Japan wax kernel oil, hydrogenated oil, beef leg fat, Japan wax, and hydrogenated castor oil.

[0033] Examples of waxes include beeswax, candelilla wax, cotton wax, carnauba wax, bayberry wax, privet wax, whale wax, montan wax, bran wax, lanolin, kapok wax, lanolin acetate, liquid lanolin, sugarcane wax, lanolin fatty acid isopropyl, hexyl laurate, reduced lanolin, jojoba wax, hard lanolin, shellac wax, POE lanolin alcohol ether, POE lanolin alcohol acetate, POE cholesterol ether, lanolin fatty acid polyethylene glycol, and POE hydrogenated lanolin alcohol ether.

[0034] Examples of hydrocarbon oils include oils such as liquid paraffin, ozokerite, squalene, pristane, paraffin, ceresin, squalene, petrolatum, and microcrystalline wax.

[0035] Examples of higher fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, 12-hydroxystearic acid, undecylenic acid, tall acid, isostearic acid, linoleic acid, linolenic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).

[0036] Examples of silicone include chain polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, and methylhydrogenpolysiloxane; cyclic polysiloxanes such as decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and tetramethyltetrahydrogenpolysiloxane; silicone resins and silicone rubbers that form a three-dimensional network structure, and the like.

[0037] Among them, it is preferable to blend wax as the component (D). When blending wax, the blending amount of wax is preferably 0.3 to 5% by mass, more preferably 0.5 to 4% by mass, and still more preferably 1 to 3% by mass, based on the total amount of the cosmetic. By blending wax at 0.3% by mass or more, the stability tends to be further improved. On the other hand, when the blending amount of wax exceeds 5% by mass, the spread during application may become heavy instead.

[0038] The blending amount of the oil component (D) (including the component (E)) in the cosmetic of the present invention is 10 to 30% by mass, preferably 12 to 27% by mass, more preferably 15 to 25% by mass, based on the total amount of the cosmetic. If the blending amount of the oil component (D) is less than 10% by mass, sufficient stability cannot be obtained, and if it exceeds 30% by mass, stickiness may occur and the elongation may deteriorate.

[0039] <E / D ratio> The blending mass ratio (%) of the polar oil (E) to the total oil component (D), that is, the E / D ratio (hereinafter, the blending mass ratio may be referred to as the "polar oil fraction") is 0.65 or more, preferably 0.7 or more, and still more preferably 0.75 or more. If the polar oil fraction is less than 0.65, stickiness may occur and the elongation may deteriorate. In addition, when an ultraviolet absorber is blended, the ultraviolet defense ability may not be sufficiently exhibited. On the other hand, there is no particular upper limit to the polar oil fraction, and the polar oil (E) may occupy all of the oil component (D).

[0040] <(E / D) / (A / (B+C))> It is generally known that the higher the polar oil ratio (E / D), the more easily the (B) nonionic surfactant and (C) fatty alcohol dissolve in the oil phase, making it more difficult to form a gel. For this reason, when forming a gel, it is important to focus on the correlation between (E / D) and (B+C) and to strike a balance between them. Since the present invention further contains component (A), the effect of component (A) on gel formation must also be considered. The inventors have conducted research and found that component (A) interacts with nonionic surfactant (B) and higher alcohol (C), and that the greater the amount of component (A), the higher the viscosity becomes, making the product less likely to crumble, and resulting in a loss of the moist and fresh feel. After further investigation, the inventors discovered that in order to achieve the desired usability, the polar oil content (E / D), the total blend amount (B+C) of the (B) nonionic surfactant and the (C) higher alcohol, and the blend amount (A) of the (A) component must satisfy the following conditions: (E / D) / (A / (B+C))>7.4

[0041] That is, if (E / D) / (A / (B+C)) is greater than 7.4, the balance between the three components is maintained, and the product remains creamy with a moderate viscosity during storage, but the shear force applied during application causes the viscosity to drop rapidly from a creamy state to a liquid state, exhibiting fluidity, allowing the product to spread smoothly and providing a fresh, non-sticky feel when used. Furthermore, to more reliably achieve this feel when used, (E / D) / (A / (B+C)) is preferably greater than 8.3, and more preferably greater than 10. On the other hand, there is no particular upper limit to (E / D) / (A / (B+C)), but taking into consideration the weight of spreading, it is preferably 25 or less, and more preferably 17 or less.

[0042] <Optional ingredients> In addition to the above components (A) to (E), the oil-in-water emulsion cosmetic of the present invention may contain, as appropriate, thickening polysaccharides, water-soluble UV absorbers, UV scattering agents, moisturizing agents, fragrances, antioxidants, preservatives, cosmetic ingredients, and the like, which are commonly used in oil-in-water emulsion cosmetics, within a range that does not impair the effects of the present invention.

[0043] In particular, while the incorporation of thickening polysaccharides into oil-in-water emulsion cosmetics generally tends to impair usability, the cosmetic of the present invention can actually improve usability and further improve smoothness of spread. Examples of thickening polysaccharides (polysaccharide thickeners) include cellulose-based thickeners such as crystalline cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and carboxymethyl cellulose; and natural polymeric polysaccharides such as gellan gum, carrageenan, guar gum, locust bean gum, gum arabic, xanthan gum, dextran, and succinoglucan. When thickening polysaccharides are incorporated, their amount is preferably 0.01 to 5% by mass, more preferably 0.05 to 3% by mass, based on the total amount of the cosmetic. Incorporation of 0.01% by mass or more of thickening polysaccharides tends to further improve stability. On the other hand, if the amount of thickening polysaccharides incorporated exceeds 5% by mass, the cosmetic may spread more slowly upon application. On the other hand, even if they are the same water-soluble thickeners, it is preferable to avoid using synthetic polymers such as vinyl polymers such as polyvinyl methyl ether and carboxyvinyl polymer (carbomer), polyoxyethylene polymers, polyoxyethylene polyoxypropylene copolymer polymers, and acrylic polymers such as polyethyl acrylate and polyacrylamide, as they may cause slime, heavy spreading, and stickiness.

[0044] In addition, in order to impart or improve the ultraviolet protection effect, a water-soluble ultraviolet absorber or an ultraviolet scattering agent may be blended. Examples of the water-soluble ultraviolet absorber include phenylbenzimidazole sulfonic acid and 2-hydroxy-4-methoxybenzophenone sulfonic acid.

[0045] Examples of ultraviolet scattering agents include titanium oxide, chromium oxide, iron oxide, zinc oxide, barium sulfate, etc. These may also be surface-hydrophobized, and examples of surface treatment methods include silicone treatment with methylhydrogenpolysiloxane, methylpolysiloxane, etc.; alkylsilane treatment; fluorine treatment with perfluoroalkyl phosphate ester, perfluoroalcohol, etc.; amino acid treatment with N-acylglutamic acid, etc.; lecithin treatment; metal soap treatment; fatty acid treatment; alkyl phosphate ester treatment, etc. However, since the incorporation of an ultraviolet scattering agent may cause a whitish appearance or a powdery feel after application, the amount to be incorporated is less than 2% by mass, more preferably less than 1% by mass, and even more preferably less than 0.5% by mass.

[0046] <Viscosity> The oil-in-water emulsion cosmetic of the present invention preferably has a viscosity at 25°C of 100,000 mPa·s or less, more preferably 90,000 mPa·s or less, and even more preferably 80,000 mPa·s or less. In the present invention, "viscosity" refers to a value measured with a Brookfield viscometer at 25°C. If the viscosity is higher than 100,000 mPa·s, the cosmetic may be difficult to break down upon application or may not spread well.

[0047] The oil-in-water emulsion cosmetic of the present invention is not limited to any particular method, but can be produced, for example, by dissolving components (A) to (E) at high temperature to prepare a dissolved oil part, adding the dissolved oil part to a heated aqueous phase part containing water and other aqueous components, emulsifying the mixture in a conventional manner, and then cooling the mixture.

[0048] The oil-in-water emulsion cosmetic of the present invention can be widely applied not only to sunscreen cosmetics but also to makeup products, hair products, and the like. [Example]

[0049] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, the blending amount is expressed in mass % relative to the system in which the component is blended. Before describing each example in detail, the evaluation methods used will be described.

[0050] <Usability> Each sample of the Examples and Comparative Examples was actually used by a panel of 10 experts, who evaluated the ease of spreading during application and the lack of stickiness after application. Each expert panel member performed a sensory evaluation on a 5-point scale according to the following evaluation criteria, and the total score was used to make a judgment based on the following evaluation criteria. "Evaluation criteria" 5: Excellent 4: Excellent 3: Normal 2: Inferior 1: Very poor "Evaluation Criteria" A: Total score is 40 or more B: Total score is 30-39 points C: Total score is 20-29 points D: Total score is 19 points or less

[0051] <UV protection effect> Each cosmetic sample was applied at 2 mg / cm to a measurement plate (S plate) (5 x 5 cm V-groove PMMA (polymethyl methacrylate) plate, SPFMASTER-PA01). 2 The test piece was applied with a finger for 40 seconds and then dried for 15 minutes to form a coating film. On the other hand, no coating was applied to the control. The absorbance of the formed coating film was measured using a Hitachi U-3500 model recording spectrophotometer, and the absorbance (Abs) was calculated according to the following formula to determine the integrated value of absorbance for irradiated light with a wavelength of 280 to 400 nm. Abs=-log(T / To) T: transmittance of sample, To: transmittance of uncoated sample The UV protection effect was evaluated based on the UV protection function value (integrated absorbance value) thus obtained, according to the following evaluation criteria. "Evaluation Criteria" A: The absorbance cumulative value is 80 or more. B: The integrated absorbance value is 72.5 or more and less than 80 C: The integrated absorbance value is 65 or more and less than 72.5 D: The integrated absorbance value is less than 65

[0052] <Viscosity> Measurement was carried out using a VDA type viscometer (Shibaura Systems Co., Ltd., DIGITAL VISMETRON VDA) at 25°C, rotor No. 6, rotation speed 10 rpm, and for 1 minute.

[0053] <Examples 1 to 8 and Comparative Examples 1 to 4> Oil-in-water emulsion cosmetics having the compositions shown in Tables 1 and 2 below were prepared and evaluated for each of the above items.

[0054] [Table 1]

[0055] [Table 2]

[0056] As shown in the table above, when the components (A) to (E) were contained, the E / D ratio was 0.65 or more, and the (E / D) / (A / (B+C)) value exceeded 7.4, the product maintained a moderate viscosity during storage, but rapidly crumbled and became liquid upon application, resulting in excellent spreadability on the skin and a refreshing, non-sticky feel (Examples 1 to 8). On the other hand, when carbomer was used instead of component (A) to increase the viscosity, or when the (E / D) / (A / (B+C)) value was 7.4 or less, it was confirmed that the usability was poor (Comparative Examples 1 to 4). In particular, when the (E / D) / (A / (B+C)) value was 7.4 or less, the viscosity was too high, making it difficult to break down upon application and difficult to spread (Comparative Examples 3 and 4). Furthermore, when the E / D ratio was less than 0.65, a high UV protection effect could not be obtained even with the same amount of UV absorber (Comparative Example 3).

Claims

1. (A) (meth)acrylic acid / alkyl (meth)acrylate / POE monoalkyl ether (meth)acrylate copolymer, (B) a nonionic surfactant, (C) a higher alcohol, and (D) Oils other than the (C) higher alcohols Including, (D) At least a portion of the oil component is (E) a polar oil having an IOB of 0.1 to 0.5, and The blending amounts (mass%) of components (A) to (E) are as follows: The blending amount of component (A) is 0.1 to 1.0% by mass based on the total amount of the cosmetic, The blending amount of component (B) is 0.1 to 10% by mass based on the total amount of the cosmetic, The blending amount of component (C) is 0.1 to 10% by mass based on the total amount of the cosmetic, The blending amount of component (D) is 10 to 30% by mass based on the total amount of the cosmetic, The blending amount of component (E) is 1 to 20% by mass based on the total amount of the cosmetic, E / D≧0.65, and (E / D) / (A / (B+C)) is greater than 7.4 and less than or equal to 25 An oil-in-water emulsion cosmetic that satisfies the above requirements.

2. 2. The oil-in-water emulsion cosmetic according to claim 1, wherein the HLB of the nonionic surfactant (B) is 10 to 19.

3. The oil-in-water emulsion cosmetic according to claim 1 or 2, comprising two or more types of higher alcohol (C).

4. The oil-in-water emulsion cosmetic according to any one of claims 1 to 3, comprising a wax as the (D) oil component, and the blending amount of the wax is 0.3 to 5 mass% with respect to the total amount of the cosmetic.

5. The oil-in-water emulsion cosmetic according to any one of claims 1 to 4, further comprising a thickening polysaccharide.

6. The oil-in-water emulsion cosmetic according to any one of claims 1 to 5, which has a viscosity at 25°C of 100,000 mPa·s or less.

7. The oil-in-water emulsion cosmetic according to any one of claims 1 to 6, comprising an oil-soluble UV absorber as at least a part of the (E) polar oil.

8. The oil-in-water emulsion cosmetic according to any one of claims 1 to 7, further comprising a water-soluble ultraviolet absorber.

9. The oil-in-water emulsion cosmetic according to any one of claims 1 to 8, wherein the blending amount of the ultraviolet scattering agent is less than 2 mass%.

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