Water-in-oil emulsified skin care products

Abstract

The purpose of the present invention is to provide a water-in-oil emulsion cosmetic preparation for skin, said cosmetic preparation having an ultraviolet light shielding effect that is improved when the cosmetic preparation has come into contact with a moisture content such as water and perspiration in comparison to the ultraviolet light shielding effect thereof right after the application, while having excellent feeling of use. The present invention relates to a water-in-oil emulsion cosmetic preparation for skin, said cosmetic preparation being characterized by containing: (A) (a-1) a copolymer that has a silanol group, and an oxypropylene group (PO) or an oxyethylene group (EO) and / or (a-2) a silylated peptide; and (B) an ultraviolet light shielding agent.

Description

[Technical Field]

[0001] The present invention relates to a water-in-oil emulsion skin cosmetic. More specifically, the present invention relates to a water-in-oil emulsion skin cosmetic containing a UV protection agent, which upon contact with water, sweat, or other moisture improves the UV protection effect compared to immediately after application and also provides an excellent feel when used. [Background technology]

[0002] Protecting skin from the harmful effects of ultraviolet rays is one of the important issues in skin care and body care, and various UV care cosmetics have been developed to minimize the adverse effects of ultraviolet rays on the skin. Sunscreen cosmetics, one type of UV care cosmetic, are cosmetics that are intended to protect the skin from the adverse effects of ultraviolet rays by covering the skin with a coating film containing ultraviolet absorbers and ultraviolet scattering agents, thereby absorbing or scattering UVA and UVB rays in sunlight and reducing the amount of ultraviolet rays that reach the skin (Non-Patent Document 1).

[0003] Sunscreen cosmetics applied to the skin are exposed to various moistures such as sweat secreted from the skin and seawater, and therefore UV absorbers and UV scattering agents are inevitably leached from the cosmetic coating applied to the skin, resulting in a decrease in UV protection efficacy. Therefore, water-in-oil emulsion cosmetics are preferably used because of their excellent water resistance.

[0004] For example, Patent Document 1 describes that by incorporating an oil phase thickener or the like into a sunscreen cosmetic containing a UV protection agent, the cosmetic has a unique and unprecedented property in which the UV protection effect is improved after the applied film of the cosmetic comes into contact with moisture such as water or sweat, compared to immediately after application of the cosmetic (before contact with moisture). However, when the cosmetic of Patent Document 1 is prepared as a water-in-oil emulsion cosmetic, the viscosity of the external phase increases due to the incorporation of the oil phase thickener, which tends to cause stickiness. Therefore, further improvements are needed, particularly in terms of usability. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2016 / 068300 [Non-patent literature]

[0006] [Non-Patent Document 1] "New Cosmetics Science", 2nd edition, edited by Takeo Mitsui, 2001, Nanzando Publishing, pp. 497-504 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention aims to provide a water-in-oil emulsified skin cosmetic which has the property that its ultraviolet protection effect is improved by contact with moisture such as water or sweat compared to immediately after application, and which also has an excellent feeling when used. [Means for solving the problem]

[0008] As a result of extensive research aimed at solving the above-mentioned problems, the present inventors have discovered that by incorporating a copolymer having a silanol group and an oxypropylene group (PO) or an oxyethylene group (EO), and / or a silylated peptide, in a water-in-oil emulsion skin cosmetic containing a UV protection agent, not only is the UV protection effect significantly improved upon contact with moisture such as water or sweat, but also an excellent feel when used, thereby completing the present invention.

[0009] That is, the present invention provides: (A) (a-1) a copolymer having a silanol group and an oxypropylene group (PO) or an oxyethylene group (EO), and (a-2) at least one selected from the group consisting of silylated peptides; and (B) A water-in-oil emulsified skin cosmetic containing an ultraviolet protection agent is provided. [Effects of the Invention]

[0010] By adopting the above-described configuration, the water-in-oil emulsion skin cosmetic of the present invention exhibits significantly improved UV protection after contact with water, sweat, etc., compared to immediately after application of the cosmetic to the skin. Furthermore, because component (A) of the present invention sufficiently improves UV protection, it is possible to reduce the amount of oil phase thickener that has conventionally been added for the purpose of improving UV protection, and a water-in-oil emulsion sunscreen cosmetic that is non-sticky and has an excellent feel when used can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0011] As described above, the water-in-oil emulsion skin cosmetic of the present invention (hereinafter, sometimes simply referred to as "cosmetic") has the following properties: (A) (a-1) a copolymer having a silanol group and an oxypropylene group (PO) or an oxyethylene group (EO) and / or (a-2) a silylated peptide, and (B) It is characterized by containing an ultraviolet protection agent as an essential component. Each component constituting the cosmetic of the present invention will be described in detail below.

[0012] Component (A) of the present invention is at least one selected from (a-1) a copolymer having a silanol group and an oxypropylene group (PO) or an oxyethylene group (EO), and (a-2) a silylated peptide. The cosmetic preparation of the present invention may contain either (a-1) or (a-2) alone, or may contain both (a-1) and (a-2).

[0013] The (a-1) copolymer having a silanol group and an oxypropylene group (PO) or an oxyethylene group (EO) blended in the cosmetic of the present invention is a copolymer that contains a polysiloxane structure and a polyoxyalkylene structure in the main chain of the polymer and has side chains containing trialkoxysilane groups or silanol groups (hereinafter referred to as a "crosslinked silicone POA copolymer").

[0014] The polysiloxane structure constituting the main chain of the (a-1) crosslinked silicone POA copolymer of the present invention is composed of a polydialkylsiloxane, preferably a polydimethylsiloxane, in which a portion of the alkyl groups (preferably methyl groups) may be substituted with phenyl groups.

[0015] The polyoxyalkylene structure constituting the main chain of the (a-1) crosslinked silicone POA copolymer of the present invention preferably contains at least one repeating unit selected from the group consisting of oxyethylene (EO), oxypropylene (PO), and oxybutylene (BO).

[0016] The crosslinked silicone POA copolymer (a-1) of the present invention preferably further has a side chain composed of an organic group. Examples of the organic group that forms the side chain include a hydrocarbon group (preferably an alkyl group, for example, a linear or branched alkyl group having about 1 to 30 carbon atoms, or a phenyl group) that may be optionally substituted with a substituent such as an amino group, a hydroxyl group, or a carboxyl group. The hydrocarbon group preferably has an amino group, and the hydrogen atom of the amino group may be further substituted with an alkyl group or the like.

[0017] The crosslinked silicone POA copolymer (a-1) of the present invention preferably further contains a nitrogen atom in its main chain, and the side chains are preferably bonded to the nitrogen atom.

[0018] A more specific example of the (a-1) crosslinked silicone POA copolymer is Polysilicone-29 (INCI name), which is defined as a composite silicone compound obtained by reacting a dimethylsiloxane polymer having a glycidoxypropyl group at the end with PEG-13 diglycidyl ether, diethylaminopropylamine, and aminopropyltriisopropoxysilane.

[0019] The (a-1) crosslinked silicone POA copolymer in the cosmetic of the present invention may be a commercially available product. For example, "Silsoft CLX-E" (manufactured by Momentive Performance Materials) is preferably used, and this copolymer is a compound belonging to the "Polysilicone-29" group. This copolymer contains a polysiloxane structure, a polyoxyalkylene structure, and a nitrogen atom in its main chain, and has a side chain containing a trialkoxysilane group and a side chain consisting of an organic group. The polysiloxane structure contains polydimethylsiloxane, the polyoxyalkylene structure contains polyoxyethylene and polyoxyisopropylene, and the side chain is bonded to the nitrogen atom of the main chain. "Silsoft CLX-E" is a commercial product containing this copolymer, dipropylene glycol, and water.

[0020] As the (a-2) silylated peptide to be blended in the cosmetic of the present invention, one represented by general formula (I) is preferably used.

[0021] [ka]

[0022] [In formula (I), R 1 , R 2 , R 3 represents an alkyl group having 1 to 3 carbon atoms or a hydroxyl group, and these R 1 , R 2 , R 3 may all be the same or different. 4 indicates a residue excluding the terminal amino group of a basic amino acid having an amino group at the end of the side chain, and R 5 is R 4 a is 1 or 3, m is 0 to 200, n is 0 to 200, and m+n is 1 to 200 (however, m and n only indicate the number of amino acids and do not indicate the order of the amino acid sequence).

[0023] The silylated peptide (a-2) represented by general formula (I) can be, for example, The following general formula (II): [ka] [In formula (II), R 6 , R 7 , R 8 represents an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, or a halogen atom, and these R 6 , R 7 , R 8 may be the same or different, and a represents 1 or 3. The following general formula (III) [ka] [In formula (III), R 4 indicates a residue excluding the terminal amino group of a basic amino acid having an amino group at the end of the side chain, and R 5 is R 4 represents an amino acid side chain other than the above, m is 0 to 200, n is 0 to 200, and m+n is 1 to 200.

[0024] In the silylated peptide (a-2) represented by the general formula (I), R 4 is a residue excluding the terminal amino group of a basic amino acid having an amino group at the end of the side chain, and examples of the basic amino acid having an amino group at the end of the side chain include lysine, arginine, and hydroxylysine. 5 is R 4 Examples of such amino acids include glutamic acid, aspartic acid, alanine, serine, threonine, valine, methionine, leucine, isoleucine, tyrosine, phenylalanine, proline, and hydroxyproline.

[0025] Peptides represented by the general formula (III) include amino acids, peptides, and esters of amino acids or peptides, such as alanine, glycine, valine, leucine, isoleucine, proline, phenylalanine, tyrosine, serine, threonine, methionine, arginine, histidine, lysine, asparagine, aspartic acid, glutamine, glutamic acid, cystine, cysteine, cysteic acid, tryptophan, hydroxyproline, hydroxylysine, O-phosphoserine, and citrulline.

[0026] The peptides include natural peptides, synthetic peptides, and hydrolyzed peptides obtained by partial hydrolysis of proteins with acid, alkali, or enzymes. Examples of natural peptides include glutathione, bacitracin A, insulin, glucagon, oxytocin, and vasopressin. Examples of synthetic peptides include polyglycine, polylysine, polyglutamic acid, and polyserine. Hydrolyzed peptides are peptides obtained by partial hydrolysis of proteins with acid, alkali, enzymes, or a combination thereof. Protein sources include animal proteins, vegetable proteins, and proteins derived from microorganisms. Examples of animal proteins include silk, collagen (including its denatured form, gelatin), keratin, fibroin, sericin, casein, conchiolin, elastin, protamine, and egg yolk and egg white proteins from chickens. Examples of vegetable proteins include proteins contained in soybeans, wheat, rice (rice bran), sesame, peas, corn, and potatoes. In addition, examples of proteins derived from microorganisms include yeast proteins isolated from yeasts of the genera Saccharomyces, Candida, and Endomycopsis, yeasts known as brewer's yeast and sake yeast, and proteins isolated from mushrooms (basidiomycetes) and chlorella.

[0027] Examples of the esters of the amino acids or peptides include esters of the carboxyl group of the amino acids or peptides with hydrocarbon alcohols having 1 to 20 carbon atoms, such as methyl esters, ethyl esters, propyl esters, isopropyl esters, lauryl esters, cetyl esters, 2-ethylhexyl esters, 2-hexyldecyl esters, and stearyl esters.

[0028] (a-2) More specific examples of silylated peptides include N-[2-hydroxy-3-(3-trihydroxysilyl)propoxy]propyl hydrolyzed protein, N-[2-hydroxy-3-(3-dihydroxymethylsilyl)propoxy]propyl hydrolyzed protein, etc.

[0029] The silylated peptide (a-2) used in the cosmetic of the present invention may be a commercially available product. Examples include "Promois S-700SIG," "Promois W-52SIG," and "Promois WS-HSIG" (all manufactured by Seiwa Kasei Co., Ltd.), with "Promois S-700SIG" being preferred. "Promois S-700SIG" is a product containing (dihydroxymethylsilylpropoxy)hydroxypropyl hydrolyzed silk, 1,3-butylene glycol, methylparaben, propylparaben, and water.

[0030] The amount of component (A) in the cosmetic of the present invention is not particularly limited, but is preferably 0.08 to 2 mass%, more preferably 0.15 to 1.5 mass%, of the total amount of the cosmetic in terms of the pure content of component (A). If the amount is less than 0.08 mass%, the effect of improving UV protection ability will be insufficient, and if it exceeds 2 mass%, stickiness will tend to occur.

[0031] The (B) ultraviolet protection agent (hereinafter sometimes simply referred to as "ingredient (B)") incorporated into the cosmetic of the present invention means an ultraviolet absorber and / or an ultraviolet scattering agent, and those that are typically incorporated into sunscreen cosmetics can be used.

[0032] Examples of ultraviolet absorbers include benzoic acid derivatives, salicylic acid derivatives, cinnamic acid derivatives, dibenzoylmethane derivatives, β,β-diphenylacrylate derivatives, benzophenone derivatives, benzylidene camphor derivatives, phenylbenzimidazole derivatives, triazine derivatives, phenylbenzotriazole derivatives, anthranil derivatives, imidazoline derivatives, benzalmalonate derivatives, 4,4-diarylbutadiene derivatives, etc. Specific examples and trade names are listed below, but the present invention is not limited to these.

[0033] Examples of benzoic acid derivatives include ethyl para-aminobenzoate (PABA), ethyl-dihydroxypropyl PABA, ethylhexyl-dimethyl PABA (e.g., Escarol 5 Ethylhexyl P25; BASF), and diethylaminohydroxybenzoyl hexyl benzoate (e.g., Uvinal A Plus).

[0034] Examples of salicylic acid derivatives include homosalate (Eusolex HMS; Rona / EM Industries), ethylhexyl salicylate or octyl salicylate (e.g., NeoHeliopan OS; Herman & Reimer), dipropylene glycol salicylate (e.g., Dipsal; Skell), and TEA salicylate (e.g., NeoHeliopan TS; Herman & Reimer).

[0035] Examples of cinnamic acid derivatives include octyl methoxycinnamate or ethylhexyl methoxycinnamate (e.g., Parsol MCX; Hoffmann-La Roche), isopropyl methoxycinnamate, isoamyl methoxycinnamate (e.g., Neo Heliopan E1000; Herman & Reimer), cinnoxate, DEA methoxycinnamate, diisopropyl methylcinnamate, glyceryl ethylhexanoate dimethoxycinnamate, and di-(2-ethylhexyl)-4'-methoxybenzalmalonate.

[0036] Examples of dibenzoylmethane derivatives include 4-tert-butyl-4'-methoxydibenzoylmethane (for example, Parsol 1789).

[0037] Examples of β,β-diphenylacrylate derivatives include octocrylene (for example, "Uvinal N539T"; BASF).

[0038] Examples of benzophenone derivatives include benzophenone-1 (e.g., "Uvinal 400"; BASF), benzophenone-2 (e.g., "Uvinal D50"; BASF), benzophenone-3 or oxybenzone (e.g., "Uvinal M40"; BASF), benzophenone-4 (e.g., "Uvinal MS40"; BASF), benzophenone-5, benzophenone-6 (e.g., "Helisorb 11"; Norquay), benzophenone-8 (e.g., "Spectra-Sorb UV-24"; American Cyanamid), benzophenone-9 (e.g., "Uvinal DS-49"; BASF), and benzophenone-12.

[0039] Examples of benzylidene camphor derivatives include 3-benzylidene camphor (e.g., "Mexoryl SD"; Cimex), 4-methylbenzylidene camphor, benzylidene camphorsulfonic acid (e.g., "Mexoryl SL"; Cimex), benzalkonium camphor methosulfate (e.g., "Mexoryl SO"; Cimex), terephthalidene discamphorsulfonic acid (e.g., "Mexoryl SX"; Cimex), and polyacrylamidomethyl benzylidene camphor (e.g., "Mexoryl SW"; Cimex).

[0040] Examples of phenylbenzimidazole derivatives include phenylbenzimidazole sulfonic acid (e.g., "Eusolex 232"; Merck) and disodium phenyldibenzimidazole tetrasulfonate (e.g., "Neo Heliopan AP"; Herman & Reimer).

[0041] Examples of triazine derivatives include bisethylhexyloxyphenol methoxyphenyl triazine (e.g., "Tinosorb S"; Ciba Specialty Chemicals), ethylhexyl triazone (e.g., "Uvinal T150"; BASF), diethylhexylbutamido triazone (e.g., "Uvasorb HEB"; Sigma-3V), 2,4,6-tris(diisobutyl-4'-aminobenzalmalonate)-s-triazine, and 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine.

[0042] Examples of phenylbenzotriazole derivatives include drometrizole trisiloxane (e.g., "Silatrizole"; Rhodia-Chemie), methylenebis(benzotriazolyltetramethylbutylphenol) (e.g., "Tinosorb M"; Ciba Specialty Chemicals).

[0043] Examples of anthranil derivatives include menthyl anthranilate (for example, "Neo Heliopan MA"; Herman & Reimer).

[0044] Examples of imidazoline derivatives include ethylhexyldimethoxybenzylidene-dioxoimidazoline propionate.

[0045] Examples of benzalmalonate derivatives include polyorganosiloxanes having benzalmalonate functional groups (for example, polysilicone-15; "Parsol SLX"; DSM Nutrition Japan).

[0046] Examples of 4,4-diarylbutadiene derivatives include 1,1-dicarboxy(2,2'-dimethylpropyl)-4,4-diphenylbutadiene.

[0047] The ultraviolet scattering agent used in the present invention is not particularly limited, but specific examples include fine particle metal oxides such as zinc oxide, titanium oxide, iron oxide, cerium oxide, and tungsten oxide.

[0048] The ultraviolet scattering agent may be untreated or may be subjected to various hydrophobic surface treatments, but those subjected to hydrophobic surface treatments are preferably used. The surface treatment agent is not particularly limited, but may be one commonly used in the field of cosmetics, for example, dimethicone, silicones such as alkyl-modified silicone, alkoxysilanes such as octyltriethoxysilane, dextrin fatty acid esters such as dextrin palmitate, and fatty acids such as stearic acid.

[0049] Component (B) in the present invention includes an embodiment consisting of only an ultraviolet absorber, an embodiment consisting of only an ultraviolet scattering agent, and an embodiment containing both an ultraviolet absorber and an ultraviolet scattering agent.

[0050] The amount of component (B) in the cosmetic of the present invention is not particularly limited, but is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, and even more preferably 10 to 20% by mass, relative to the total amount of the cosmetic. If the amount of component (B) is less than 5% by mass, it may be difficult to obtain a sufficient UV protection effect, and even if it is added in an amount exceeding 40% by mass, an increase in UV protection effect commensurate with the amount added cannot be expected and emulsion stability may be impaired, which are undesirable.

[0051] The cosmetic of the present invention having such a configuration has the property that its UV protection effect (absorbance) improves when it comes into contact with water. "The UV protection effect (absorbance) improves upon contact with water" can be roughly defined as follows: A predetermined amount of a sample of the emulsion-type cosmetic is dropped onto a measurement plate, applied to a predetermined area, and dried to form a coating film. The absorbance of the coating film is measured using a spectrophotometer or the like, and the integrated absorbance value (Abs) of the coating film (before water bathing) is calculated using the absorbance of a coating film of a substance that does not absorb UV rays (e.g., glycerin) as a standard. before )

[0052] Next, the measurement plate on which the coating film was formed was immersed in water under predetermined conditions, and the coating film (after the water bath) was dried and then measured for the integrated absorbance (Abs after ) is measured in the same manner. The rate of change in absorbance before and after the water bath (Abs rate of change) is calculated according to the following formula. Abs change rate (%) = [(Abs after ) / (Abs before )] × 100 When the Abs change rate exceeds 100%, it is defined as an improvement in UV protection effect.

[0053] In the cosmetic of the present invention, the Abs change rate exceeds at least 100%, preferably 105% or more, more preferably 110% or more, even more preferably 115% or more, and particularly preferably 120% or more.

[0054] In order to further improve the UV protection effect, the cosmetic composition of the present invention may contain, in addition to components (A) and (B), an oil phase thickener (C) (hereinafter sometimes simply referred to as "component (C)"). The incorporation of component (C) synergistically improves the UV protection ability provided by component (A) of the present invention.

[0055] The component (C) used in the cosmetic of the present invention is not particularly limited, but can be appropriately selected from substances used in emulsion cosmetics and the like as components that thicken the oil phase by dissolving in oil or swelling with oil. Specific examples include dextrin fatty acid esters such as dextrin palmitate and dextrin myristate; sucrose fatty acid esters such as sucrose caprylate; higher fatty acids having 8 to 22 carbon atoms that are solid at room temperature, such as lauric acid, myristic acid, palmitic acid, and stearic acid, or salts thereof; and organically modified clay minerals such as disteardimonium hectorite and benzyldimethylstearylammonium hectorite. Of these, it is preferable to use one or a combination of two or more of the organically modified clay minerals, dextrin fatty acid esters, and sucrose fatty acid esters.

[0056] The amount of component (C) in the cosmetic of the present invention is not particularly limited, but is preferably 0.1 to 3 mass % and more preferably 0.3 to 1 mass % relative to the total amount of the cosmetic. The greater the amount of component (C), the more likely it is to cause stickiness.

[0057] In addition to the above ingredients, the cosmetic of the present invention contains oil and water that constitute a water-in-oil emulsified skin cosmetic, and optionally contains a surfactant (emulsifier).

[0058] The surfactant used in the cosmetic of the present invention is not particularly limited as long as it is one that is commonly used in water-in-oil emulsion cosmetics, but from the viewpoint of usability, surfactants having a silicone skeleton (polysiloxane structure) and an HLB value of less than 8 are preferred. For example, polyether-modified silicones, polyether-alkyl co-modified silicones, polyglycerin-modified silicones, and / or polyglycerin-alkyl co-modified silicones are preferably used, and among these, polyether-modified silicones and polyether-alkyl-modified silicones are more preferred.

[0059] The amount of the surfactant to be added is not particularly limited, but is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, based on the total amount of the cosmetic.

[0060] The oil used in the cosmetic of the present invention is not particularly limited, but examples thereof include liquid oils and fats such as avocado oil, camellia oil, macadamia nut oil, mink oil, olive oil, castor oil, jojoba oil, triglycerin, and glycerin trioctanoate; hydrocarbon oils such as liquid paraffin, squalane, paraffin, ceresin, and squalene; higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, 12-hydroxystearic acid, isostearic acid, linoleic acid, and linolenic acid; higher alcohols such as lauryl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, oleyl alcohol, monostearyl glycerol ether, monopalmityl glycerol ether, cholesterol, phytosterol, and isostearyl alcohol; isononyl isononanoate, myristic acid Examples of the oil include isopropyl, cetyl octanoate, octyldodecyl myristate, butyl stearate, decyl oleate, ethylene glycol dioctanoate, diisostearyl malate, trimethylolpropane trioctanoate, trimethylolpropane triisostearate, pentaerythritol tetraoctanoate, glycerin trioctanoate, glycerin triisostearate, ethyl acetate, butyl acetate, amyl acetate, and other ester oils; linear silicone oils such as dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, and diphenylsiloxyphenyltrimethicone; and cyclic silicone oils such as decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and octamethylcyclotetrasiloxane, and these can be used alone or in combination of two or more.From the viewpoint of usability, silicone oil is preferred as the oil.

[0061] The blending amount of the oil component is not particularly limited, but is preferably 10 to 70 mass % of the total amount of the cosmetic, more preferably 15 to 70 mass %, and even more preferably 20 to 70 mass %. By containing an oil component in this range, the cosmetic spreads well and has excellent water resistance and feel when used.

[0062] The water used in the cosmetic of the present invention is preferably ion-exchanged water or purified water. The water content is determined appropriately, but is preferably 1 to 30% by mass based on the total amount of the cosmetic.

[0063] In addition to the above-mentioned components, the cosmetic of the present invention may contain, as needed, ingredients commonly used in cosmetics, such as moisturizers, film-forming agents, aqueous phase thickeners, alcohols, chelating agents, coloring materials, pigments, pearling agents, antioxidants (antioxidants), fragrances, various medicinal ingredients, preservatives, etc.

[0064] The cosmetic of the present invention can be produced according to a method conventionally used for producing water-in-oil emulsions. For example, the water-in-oil emulsion skin cosmetic of the present invention can be obtained by separately preparing an aqueous phase component and an oil phase component, then mixing these aqueous and oil phases and emulsifying them using a homomixer or the like.

[0065] The specific formulation of the cosmetic of the present invention is not particularly limited, but may be a lotion, emulsion, cream, lotion, spray, etc. that exhibits a sunscreen effect that improves after bathing in water. The cosmetic of the present invention can be produced using a conventional method suitable for each formulation. [Example]

[0066] The present invention will be described in further detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, the blending amounts are expressed in mass % relative to the total amount of the cosmetic. Before describing each example in detail, the evaluation methods used will be described.

[0067] <UV protection ability improvement effect> Each cosmetic sample was applied at 2 mg / cm to a measurement plate (S plate) (5 x 5 cm V-groove PMMA plate, SPFMASTER-PA01). 2The absorbance of the coating film formed after 15 minutes of drying was measured using a Hitachi U-3500 model recording spectrophotometer. Using glycerin, which has no UV absorption, as a control, the absorbance (Abs) was calculated using the following formula, and the measured values ​​from 280 nm to 400 nm were integrated to obtain the integrated absorbance value. Abs=-log(T / To) T: transmittance of sample, To: transmittance of glycerin The plate was thoroughly immersed in water with a hardness of 50 to 500 and stirred for 30 minutes (300 rpm with a 3-1 motor). After that, it was dried for 15 to 30 minutes until all water droplets on the surface disappeared, and the absorbance was measured again, and the integrated absorbance value was calculated in the same manner as above.

[0068] Next, the Abs change rate (using the following formula) was calculated from the integrated Abs values ​​before and after bathing, and used as an index of the improvement effect of UV protection ability. UV protection ability improvement effect: Abs change rate (%) = [(Abs after ) / (Abs before )] x 100

[0069] <Feeling of use> Each sample was actually used by a panel of 10 experts, who conducted a sensory evaluation of the feel in use (non-stickiness) on a four-point scale according to the following evaluation criteria. "Evaluation Criteria" A: Very non-sticky compared to the control. B: Less sticky than the control. C: Stickiness equivalent to that of the control. D: Stickier than the control.

[0070] <Examples 1 and 2 and Comparative Example 1> Water-in-oil emulsion skin cosmetics having the compositions shown in Table 1 below were prepared according to standard methods. The UV protection effect was evaluated according to the evaluation method described above. The results are also shown in the table.

[0071] [Table 1]

[0072] As shown in Table 1 above, when component (A) of the present invention was not blended into a cosmetic composition that did not contain an oil phase thickener (Comparative Example 1), the UV protection effect decreased after bathing in water, whereas when component (A) of the present invention was blended (Examples 1 and 2), the UV protection ability after bathing in water was significantly improved.

[0073] <Examples 3 to 6 and Comparative Example 2> Water-in-oil emulsion skin cosmetics having the compositions shown in Table 2 below were prepared according to standard methods. The UV protection effect and usability were evaluated according to the evaluation methods described above. Comparative Example 2 was used as a control for evaluating usability. The results are also shown in the table.

[0074] [Table 2]

[0075] As shown in Table 2 above, Comparative Example 2 (control) contains disteardimonium hectorite, which is listed in Patent Document 1 as an ingredient that improves UV protection after bathing, and therefore has the effect of improving UV protection after bathing. On the other hand, when component (A) of the present invention was blended and disteardimonium hectorite was further added (Examples 3 to 6), the effect of improving UV protection after bathing was greater than that of Comparative Example 2. In addition, stickiness was reduced compared to Comparative Example 2, and the feel of use was extremely good.

[0076] <Example 7 and Comparative Example 3> Water-in-oil emulsion skin cosmetics having the compositions shown in Table 3 below were prepared according to standard methods. The UV protection effect was evaluated according to the evaluation method described above. The results are also shown in the table.

[0077] [Table 3]

[0078] The improvement in UV protection ability after bathing in a case where component (A) of the present invention and an oil phase thickener (component (C)) were combined (Example 7) was compared with a case where only component (A) of the present invention was included (Example 1) and a case where only component (C) was included (Comparative Example 3). As is clear from the results shown in Table 3, it was confirmed that the combination of component (A) and component (C) synergistically increased the improvement in UV protection ability after bathing.

Claims

1. (A) (a-1) a copolymer having a silanol group and an oxypropylene group (PO) or an oxyethylene group (EO), and (a-2) at least one selected from silylated peptides, (B) an ultraviolet protection agent, and (C) an oil phase thickener; the (a-1) copolymer is a copolymer containing a polysiloxane structure and a polyoxyalkylene structure in its main chain and having a side chain having a trialkoxysilane group or a silanol group, the (a-2) silylated peptide is an N-[2-hydroxy-3-(3-trihydroxysilyl)propoxy]propyl hydrolyzed protein or an N-[2-hydroxy-3-(3-dihydroxymethylsilyl)propoxy]propyl hydrolyzed protein; The water-in-oil emulsion skin cosmetic preparation, wherein the component (C) is one or more selected from the group consisting of an organically modified clay mineral, a dextrin fatty acid ester, and a sucrose fatty acid ester.

2. 2. The water-in-oil emulsion skin cosmetic according to claim 1, wherein the blending amount of the component (A) is 0.08 to 2% by mass.

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