External preparation for skin

Abstract

To provide an external preparation for skin that includes an ultraviolet absorber-containing microcapsule, wherein the external preparation does not show aggregation or precipitation during its storage and also has little change in viscosity over time.SOLUTION: An external preparation for skin includes: a microcapsule that contains an ultraviolet absorber with silylated peptide / silane compound copolymers or silylated amino acid / silane compound copolymers as a wall film; and an aqueous thickener that is selected from a composition including an acrylamide compound, a nonionic surfactant and a hydrocarbon oil, bis-stearyl PEG / PPG-8 / 6 SMDI / PEG-400 copolymer, and xanthan gum.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a topically applied skin preparation containing microcapsules encapsulating an ultraviolet absorber and having excellent storage stability. More specifically, (A) microcapsules encapsulating an ultraviolet absorber with a copolymer of a silylated peptide and a silane compound or a copolymer of a silylated amino acid and a silane compound as a wall material, and (B) a specific aqueous thickener are combined and formulated, so that the present invention relates to a topically applied skin preparation in which the viscosity change over time during storage, aggregation, and precipitation of the microcapsules are suppressed.

Background Art

[0002] Organopolysiloxanes are used in a wide range of fields because they have excellent properties such as being thermally and mechanically stable, having light resistance, and being biocompatible. In the field of microcapsules such as microcapsules and nanocapsules, microcapsules using organopolysiloxanes or similar compounds as wall materials have been produced, and the present inventors have also developed microcapsules encapsulating an ultraviolet absorber using a copolymer of a silylated peptide and a silane compound as a wall material as an excellent ultraviolet protectant (Patent Document 1).

[0003] Furthermore, as microcapsules having little leakage of the encapsulated substance, almost no odor derived from the wall material, having a wide pH stability, being excellent in stability without associating with coexisting substances when formulated in cosmetics, and being able to sufficiently exhibit the activity of the encapsulated substance, microcapsules encapsulating an ultraviolet absorber using a copolymer of a silylated amino acid and a silane compound as a wall material have been developed, and cosmetics containing the microcapsules have also been developed (Patent Document 2).

[0004] However, when these microcapsules containing an ultraviolet absorber are incorporated into a topical skin preparation, depending on the dosage form, it has sometimes been difficult to maintain the dispersibility of the microcapsules, such as aggregation of the microcapsules and precipitation of the aggregates over time during storage. Also, even when a thickening agent is incorporated to maintain dispersibility, an increase or decrease in viscosity over time may occur, potentially impairing storage stability, or depending on the type of thickening agent, the feel of use, such as stickiness or skin compatibility, may deteriorate when applied to the skin.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention provides a topical skin preparation in which microcapsules containing an ultraviolet absorber are uniformly dispersed, and there is no risk of aggregation of the microcapsules or precipitation of the aggregates even during storage, and also has little change in viscosity over time. The object is to provide a topical skin preparation for preventing ultraviolet rays.

Means for Solving the Problems

[0007] As a result of intensive studies in view of the above circumstances, the present inventors have found that one or more silylated peptides or silylated amino acids having two or more hydroxyl groups directly bonded to a silicon atom, and one or more silane compounds that generate two or more hydroxyl groups directly bonded to a silicon atom by hydrolysis are subjected to polycondensation in an aqueous solution to obtain a silylated peptide / silane compound copolymer or a silylated amino acid / silane compound copolymer as a wall film, and an ultraviolet absorber encapsulated therein. By combining with a specific aqueous thickener, aggregation and precipitation of the above microcapsules are suppressed during storage, and an excellent external preparation for skin with little change in viscosity over time is obtained, thus completing the present invention. That is, the above problems are solved by an external preparation for skin having the following configuration.

[0008] The first aspect of the present invention is (A) a structural unit U represented by the following general formula (Ia), (Ib) or (Ic): [Chemical formula] [In the formula, R 2 represents an alkyl group having 1 to 20 carbon atoms, and each R 2 may be the same or different from each other.], and a structural unit W represented by the following general formula (Id) or (Ie): [Chemical formula] [In the formula, R 1 represents an alkyl group having 1 to 3 carbon atoms, and each R 1They may be the same or different, A is a divalent group that binds Si and N, and is at least one group selected from the group consisting of -CH2-, -CH2CH2-, -CH2CH2CH2-, *-(CH2)3OCH2CH(OH)CH2- and *-(CH2)3OCOCH2CH2- (* represents the side that binds to Si), E represents a polypeptide having a number average molecular weight of 100 to 50,000 or a residue obtained by removing one primary amino group from an α-amino acid], a silylated peptide / silane compound copolymer, or a silylated amino acid / silane compound copolymer as a wall film, an encapsulated microcapsule containing an ultraviolet absorber, and (B) a composition containing an acrylamide-based compound, a nonionic surfactant, and a hydrocarbon oil, bisstearyl PEG / PPG-8 / 6 (SMDI / PEG-400) copolymer, and xanthan gum, and provides a skin external preparation characterized by containing an aqueous thickener selected from the group consisting of xanthan gum.

[0009] A second aspect of the present invention is the skin external preparation of the first aspect of the present invention, wherein the acrylamide-based compound is selected from polyacrylamide, (hydroxyethyl acrylate / sodium acryloyldimethyltaurate) copolymer, (sodium acrylate / sodium acryloyldimethyltaurate) copolymer, (acrylamide / ammonium acrylate) copolymer, (acrylamide / sodium acryloyldimethyltaurate) copolymer, and polyacrylate-13. When the acrylamide-based compound in the composition containing the acrylamide-based compound, the nonionic surfactant, and the hydrocarbon oil is one of these specific acrylamide-based compounds, it is excellent in terms of the effect of maintaining the dispersibility of the microcapsules containing the ultraviolet absorber in the skin external preparation of the present invention and the effect of suppressing the viscosity change during storage. Therefore, the second aspect of the present invention corresponds to this preferred mode.

Effects of the Invention

[0010] The present invention relates to a topical skin preparation for preventing ultraviolet rays, which contains microcapsules encapsulating an ultraviolet absorber, and the capsules are uniformly dispersed in the preparation, and aggregation and precipitation hardly occur even during storage. Further, it is excellent in that the viscosity change over time is suppressed and the stability of the dosage form of the topical skin preparation is maintained. When applied to the skin, it exhibits an excellent ultraviolet protection effect and also exhibits favorable usability such as low stickiness and good skin compatibility.

Mode for Carrying Out the Invention

[0011] Regarding the component (A) microcapsules encapsulating an ultraviolet absorber and the component (B) aqueous thickener that constitute the topical skin preparation of the present invention, and further regarding the form of the topical skin preparation of the present invention, the following will be specifically described.

[0012] [Microcapsules Encapsulating an Ultraviolet Absorber] The microcapsules encapsulating an ultraviolet absorber, which is the component (A) incorporated in the topical skin preparation of the present invention, are microcapsules having an ultraviolet protection effect in which an ultraviolet absorber is encapsulated in a capsule having a copolymer of a silylated peptide and a silane compound as a wall material or a capsule having a copolymer of a silylated amino acid and a silane compound as a wall material. These microcapsules can be produced by the methods described in Patent Document 1 or Patent Document 2, and specifically, they are as follows.

[0013] The microcapsules encapsulating an ultraviolet absorber having a copolymer of a silylated peptide and a silane compound as a wall material are represented by the following general formula (III)

Chemical formula

[0014] The silylated peptide can be produced, for example, by the production method described in JP-A-8-59424 or JP-A-8-67608. Specifically, first, a silane coupling agent having two or more hydroxyl groups directly bonded to a silicon atom is produced. The produced silane coupling agent having two or more hydroxyl groups directly bonded to a silicon atom is dropped into an aqueous peptide solution that is being heated and stirred under basic conditions of pH 9 to 11, and the two are brought into contact so that the silane coupling agent binds to the amino group of the peptide, and a peptide having a silyl functional group having two or more hydroxyl groups bonded to a silicon atom as represented by the general formula (III) is obtained.

[0015] The silane coupling agent having two or more hydroxyl groups directly bonded to a silicon atom can be produced, for example, by stirring a silane coupling agent having an alkoxy group directly bonded to a silicon atom in an acidic or basic aqueous solution at 30 to 50 °C for about 5 to 20 minutes to convert the alkoxy group directly bonded to the silicon atom into a hydroxyl group. However, when a silane coupling agent having an alkoxy group directly bonded to a silicon atom is dropped into a solution in the pH range of 9 to 11 for reacting the silane coupling agent with the peptide, the alkoxy group is hydrolyzed and changed into a hydroxyl group. That is, it is not necessary to pre-hydrolyze the silane coupling agent having an alkoxy group, and it can be carried out by directly adding a silane coupling agent having an alkoxy group to an aqueous peptide solution having a pH of 9 to 11.

[0016] Examples of the silylated peptide include N-[2-hydroxy-3-(3'-trihydroxysilyl)propoxy]propyl hydrolyzed protein, N-[2-hydroxy-3-(3'-dihydroxymethylsilyl)propoxy]propyl hydrolyzed protein, N-(3-trihydroxysilyl)propyl hydrolyzed protein, N-(3-dihydroxymethylsilyl)propyl hydrolyzed protein, and the like. The peptide used for producing the silylated peptide is not particularly limited as long as it is used in cosmetics, but hydrolyzed protein is preferred. The hydrolyzed protein is a peptide obtained by partially hydrolyzing a protein with an acid, an alkali, an enzyme, or a combination thereof. Examples of the protein source include animal proteins, plant proteins, and proteins derived from microorganisms. Examples of the animal protein include collagen (including gelatin, which is a denatured product thereof), keratin, silk protein (fibroin or sericin), casein, conchiolin, elastin, protamine, egg yolk proteins such as those of chicken, and egg white proteins. Examples of the plant protein include proteins contained in soybeans, wheat, rice (rice bran), sesame, peas, corn, potatoes, and the like. Examples of the protein derived from microorganisms include yeast proteins isolated from yeasts of the genus Saccharomyces, the genus Candida, the genus Endomycopsis, such as brewer's yeast and sake yeast, proteins isolated from mushrooms (basidiomycetes) and chlorella, and spirulina protein derived from seaweed, but are not limited thereto. Furthermore, the number average molecular weight of the hydrolyzed protein is preferably from 100 to 50,000, particularly preferably from 200 to 5,000.

[0017] From the viewpoint of easy industrial availability, as the silylated peptide of the silylated peptide / silane compound copolymer constituting the wall material of the microcapsule containing the ultraviolet absorber, silylated hydrolyzed silk protein is preferred.

[0018] The silylated amino acid can be produced by the production methods described in JP-A-2017-132713 and JP-A-2017-218392. Specifically, first, a silane coupling agent having two or more hydroxyl groups directly bonded to a silicon atom is produced. The produced silane coupling agent having two or more hydroxyl groups directly bonded to the silicon atom is dropped into an aqueous α-amino acid solution that is being heated and stirred under basic conditions of pH 9 to 11, and the two are brought into contact with each other, so that the silane coupling agent binds to the amino group of the α-amino acid, and an amino acid having a silyl functional group having two or more hydroxyl groups bonded to a silicon atom as represented by the general formula (III) is obtained. In the case of an α-amino acid having other amino groups in addition to the α-amino group (basic amino acid, for example, lysine), the amino group reacting with the silane coupling agent may be either the α-amino group or the other amino group.

[0019] A silane coupling agent having two or more hydroxyl groups directly bonded to a silicon atom can be produced, for example, by stirring a silane coupling agent having an alkoxy group directly bonded to a silicon atom in an acidic or basic aqueous solution at 30 to 50 ° C. for about 5 to 20 minutes to convert the alkoxy group directly bonded to the silicon atom into a hydroxyl group. However, when a silane coupling agent having an alkoxy group directly bonded to a silicon atom is dropped into a solution in the pH range of 9 to 11 for reacting the silane coupling agent with an amino acid, the alkoxy group is hydrolyzed and changed into a hydroxyl group. That is, it is not necessary to hydrolyze the silane coupling agent having an alkoxy group in advance, and it can be carried out by directly adding a silane coupling agent having an alkoxy group to an aqueous amino acid solution adjusted to pH 9 to 11.

[0020] As the silylated amino acids, specifically, N-[2-hydroxy-3-(3'-trihydroxysilyl)propoxy]propyl amino acid, N-[2-hydroxy-3-(3'-dihydroxymethylsilyl)propoxy]propyl amino acid, N-(3-trihydroxysilyl)propyl amino acid, N-(3-dihydroxymethylsilyl)propyl amino acid, etc. can be mentioned. The α-amino acid used for the production of the silylated amino acid is not particularly limited as long as it is used in cosmetics. For example, acidic amino acids such as aspartic acid and glutamic acid, neutral amino acids such as glycine, alanine, serine, threonine, methionine, cysteine, valine, leucine, isoleucine, phenylalanine, tyrosine, proline, hydroxyproline, tryptophan, asparagine, and glutamine, and basic amino acids such as arginine, lysine, histidine, and ornithine can all be used.

[0021] As the α-amino acid constituting the silylated amino acid, hydrophilic amino acids are preferred. Therefore, as the silylated amino acid, those having both a hydrophobic part and a hydrophilic part are preferred. Here, the hydrophilic amino acid refers to those having a solubility in water at 25 °C of 10% or more, and examples include aspartic acid, glutamic acid, glycine, alanine, serine, and proline. Among the hydrophilic amino acids, the use of neutral amino acids without a charge is more preferred because they are better incorporated into the dispersed phase and stronger and more stable capsules with better stability can be obtained. That is, serine, glycine, alanine, proline, etc. of neutral amino acids are more preferred.

[0022] The α-amino acid used in the reaction may be one kind of amino acid or a mixture of two or more kinds of amino acids. However, since the reactivity with the silane coupling agent may differ depending on the amino acid, in the case of an amino acid mixture, it may lead to a decrease in the reaction rate of the formation of the silylated amino acid that becomes the capsule wall film. Therefore, in the production of the silylated amino acid, it is desirable to silylate using one kind of amino acid and mix it when preparing the microcapsules.

[0023] From the viewpoint of industrial availability, as the silylated amino acid of the silylated amino acid-silane compound copolymer that constitutes the wall material of the microcapsules containing the ultraviolet absorber, silylated hydrolyzed serine is preferred.

[0024] Examples of the silane compound copolymerized with the silylated peptide or silylated amino acid include tetramethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, n-propyltrimethoxysilane, diisopropyldimethoxysilane, isobutyltrimethoxysilane, diisobutyldimethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, octadecyltrimethoxysilane, phenyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, octyltriethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, hexyltriethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, and the like.

[0025] The microcapsules containing the ultraviolet absorber with the copolymer of the silylated peptide and the silane compound as the wall material can be produced by the methods described in Patent Document 1 and Patent Document 2. Specifically, an aqueous solution of the silylated peptide or silylated amino acid is adjusted to pH 1 to 5, preferably pH 2 to 4, and in the range of -5°C to 90°C, preferably 5°C to 75°C, more preferably 40 to 60°C, while stirring at 100 to 400 rpm, preferably 200 to 300 rpm, the silane compound represented by the general formula (IV) is added, and after the addition is completed, stirring is continued at 40 to 60°C for reaction, and then the pH is adjusted to about 5 to 7 to obtain a prepolymer. Examples of the acid agent used for pH adjustment include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, and organic acids such as acetic acid, and examples of the alkali agent include sodium hydroxide, potassium hydroxide, and the like.

[0026] Next, while stirring the dispersion containing the prepolymer prepared above at 500 to 700 rpm, preferably about 550 to 650 rpm, at 30 to 70 °C, preferably 45 to 55 °C, an ultraviolet absorber serving as the core substance to be encapsulated or a solution in which the ultraviolet absorber is dissolved in a liquid oily substance is added over 30 minutes to 3 hours. After the addition is completed, the dispersion is further stirred with a homomixer at 5,000 to 15,000 rpm, preferably 8,000 to 12,000 rpm, for 2 to 5 hours to sufficiently perform emulsification and form a wall film.

[0027] Encapsulated microcapsules can be obtained as described above. However, there may be hydroxyl groups remaining in the silane compound condensate that forms the wall film. If hydroxyl groups remain, the hydroxyl groups on the capsule surface may bond to each other, causing the capsules to aggregate and precipitate. Therefore, it is preferable to perform surface treatment of the capsules for preventing aggregation on the encapsulated microcapsules obtained as described above.

[0028] Surface treatments such as capsule wall film hardening treatment and aggregation prevention treatment can be performed by adding a surface treatment silane compound that has been hydrolyzed in advance to generate hydroxyl groups to the dispersion containing the capsules, or by adjusting the dispersion containing the capsules to the pH at which the silane compound used for surface treatment hydrolyzes and adding the silane compound thereto. That is, it is performed by adjusting the dispersion solution containing the capsules to pH 2 to 4, preferably in the range of 40 °C to 75 °C, and adding the silane compound while stirring at 300 to 800 rpm. After the addition is completed, stirring is continued for 2 to 5 hours to allow sufficient reaction.

[0029] As the surface treatment silane compound, for example, trimethylsilyl chloride (trimethylchlorosilane), triethylsilyl chloride (triethylchlorosilane), t-butyldimethylsilyl chloride (t-butyldimethylchlorosilane), triisopropylsilyl chloride (triisopropylchlorosilane), trimethylethoxysilane, triphenylethoxysilane, etc. can be used.

[0030] When producing ultraviolet absorber - encapsulated microcapsules having a copolymer of the above - mentioned silane compound monomer and a silylated peptide or silylated amino acid as the wall material, i.e., a copolymer of a silylated peptide and a silane compound or a copolymer of a silylated amino acid and a silane compound, one or more kinds of ultraviolet absorbers may be mixed and used. The ultraviolet absorber can be encapsulated in the range of 0.01 to 99% by mass based on the total mass of the microcapsules. However, considering the ease of preparation of the microcapsules and the ultraviolet - protecting effect of the prepared microcapsules, the encapsulation rate of the ultraviolet absorber is preferably 80 to 95% by mass of the total mass of the microcapsules. That is, when the amount of the ultraviolet absorber to be encapsulated is small, the ultraviolet - protecting effect of the ultraviolet - protecting agent encapsulated in the microcapsules becomes low. Therefore, when formulated in cosmetics for the purpose of ultraviolet protection, a large amount must be formulated, which may impair the usability of the cosmetics. On the other hand, if the encapsulation rate of the ultraviolet absorber is extremely increased, the proportion of the wall - material part in the total amount of the microcapsules decreases, and the stability of the microcapsules may decrease.

[0031] Examples of the ultraviolet absorber encapsulated in the microcapsules include benzophenone derivatives such as 2-hydroxy-4-methoxybenzophenone, sodium 2-hydroxy-4-methoxybenzophenone-5-sulfonate, sodium dihydroxydimethoxybenzophenone-sulfonate, 2,4-dihydroxybenzophenone, and tetrahydroxybenzophenone; para-aminobenzoic acid derivatives such as para-aminobenzoic acid, ethyl para-aminobenzoate, glyceryl para-aminobenzoate, amyl para-dimethylaminobenzoate, and octyl para-dimethylaminobenzoate; methoxycinnamic acid derivatives such as ethyl para-methoxycinnamate, isopropyl para-methoxycinnamate, 2-ethylhexyl para-methoxycinnamate (ethylhexyl methoxycinnamate), sodium para-methoxycinnamate, potassium para-methoxycinnamate, and glyceryl dipara-methoxycinnamate mono-2-ethylhexanoate; salicylic acid derivatives such as octyl salicylate, phenyl salicylate, homomenthyl salicylate, dipropylene glycol salicylate, ethylene glycol salicylate, myristyl salicylate, and methyl salicylate; urocanic acid, ethyl urocanate, 4-tert-butyl-4'-methoxydibenzoylmethane (t-butylmethoxydibenzoylmethane), 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, methyl anthranilate, octocrylene (2-ethylhexyl 2-cyano-3,3-diphenylacrylate), 2-(4-diethylamino-2-hydroxybenzoyl)benzoic acid hexyl (diethylaminohydroxybenzoyl benzoic acid hexyl), bis-ethylhexyloxyphenol methoxyphenyltriazine, and octyltriazine. Among them, 2-ethylhexyl para-methoxycinnamate, 4-tert-butyl-4'-methoxydibenzoylmethane, octocrylene, and 2-(4-diethylamino-2-hydroxybenzoyl)benzoic acid hexyl are preferably used. However, the present invention is not limited to the above-exemplified substances. In addition, the encapsulated substance may contain other components other than the ultraviolet absorber as long as the object of the present invention is not impaired.

[0032] Examples of commercially available microcapsules containing such ultraviolet absorbers include Silasoma ME (polysilicone-14, ethylhexyl methoxycinnamate, water), Silasoma MEA (polysilicone-14, ethylhexyl methoxycinnamate, t-butylmethoxydibenzoylmethane, water), Silasoma REA(S) (polysilicone-14, octocrylene, t-butylmethoxydibenzoylmethane, water), Silasoma EP(S) (polysilicone-14, ethylhexyl methoxycinnamate, hexyl diethylaminohydroxybenzoyl benzoate, water), Silasoma SP (polysilicone-35, ethylhexyl methoxycinnamate, hexyl diethylaminohydroxybenzoyl benzoate, water), etc. manufactured by Showa Kasei Kogyo Co., Ltd.

[0033] The ultraviolet absorber encapsulated in the microcapsules containing an ultraviolet absorber having a copolymer of a silylated peptide and a silane compound as a wall film or the microcapsules containing an ultraviolet absorber having a copolymer of a silylated amino acid and a silane compound as a wall film may be used singly or in combination of two or more.

[0034] The content of the microcapsules containing the ultraviolet absorber of component (A) in the external preparation for skin of the present invention is preferably 0.5 to 30% by mass, more preferably 1 to 20% by mass, based on the total mass of the external preparation for skin. When the content of component (A) is less than this, sufficient effects as an ultraviolet protection component may not be exhibited, and when the content is more than this, there is a risk of aggregation or precipitation of the capsules.

[0035] [Aqueous thickener] The thickener as component (B) contained in the external preparation for skin of the present invention is an aqueous thickener selected from acrylamide compounds, a composition containing a nonionic surfactant and a hydrocarbon oil, bisstearyl PEG / PPG-8 / 6 (SMDI / PEG-400) copolymer, and xanthan gum. By containing these specific thickeners, aggregation of the microcapsules encapsulating the ultraviolet absorber of component (A) and reduction in viscosity of the preparation over time can be suppressed, and when applied to the skin, favorable usability such as low stickiness and good skin affinity can be exhibited.

[0036] Examples of the acrylamide compound in the composition containing an acrylamide compound, a nonionic surfactant, and a hydrocarbon oil include polyacrylamide and acrylamide copolymers. Examples of the acrylamide copolymer include copolymers containing acrylamide and / or acryloyldimethyltaurine as constituent units.

[0037] Specific examples of the acrylamide compound include polyacrylamide, (sodium acrylate / sodium acryloyldimethyltaurine) copolymer, (hydroxyethyl acrylate / sodium acryloyldimethyltaurine) copolymer, (acrylamide / ammonium acrylate) copolymer, (acrylamide / sodium acryloyldimethyltaurine) copolymer, polyacrylate-13 (copolymer of acrylic acid, acrylamide, sodium acrylate, and sodium acryloyldimethyltaurine), etc. Among them, (hydroxyethyl acrylate / sodium acryloyldimethyltaurine) copolymer and polyacrylate-13 are preferably used.

[0038] Examples of nonionic surfactants include fatty acid esters of polyhydric alcohols such as glycerin fatty acid esters and their polyalkylene glycol adducts, polyglycerin fatty acid esters and their polyalkylene glycol adducts, propylene glycol fatty acid esters and their polyalkylene glycol adducts, sorbitan fatty acid esters and their polyalkylene glycol adducts, fatty acid esters of sorbitol and their polyalkylene glycol adducts, polyalkylene glycol fatty acid esters such as polyethylene glycol fatty acid esters, sucrose fatty acid esters, polyoxyalkylene alkyl ethers, polyoxyethylene alkyl ether phosphates, alkyl ethers of polyhydric alcohols such as glycerin alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene hydrogenated castor oil, alkylene glycol adducts of lanolin, polyoxyalkylene alkyl copolymerized silicones, polyether-modified silicones, alkyl polyglucosides, and the like.

[0039] Among these, polyoxyalkylene alkyl ethers and polyalkylene glycol adducts of sorbitan fatty acid esters are preferably used. Among them, laureth-7, PEG-7 trimethylolpropane coconut oil alkyl ether, polysorbate 20, polysorbate 60, and polysorbate 80 are particularly preferably used.

[0040] Examples of hydrocarbon oils include (C13-15) alkane, (C15-19) alkane, (C18-21) alkane, (C21-28) alkane, (C10,11) isoparaffin, (C10-13) isoparaffin, (C13,14) isoparaffin, (C13-16) isoparaffin, isododecane, isohexadecane, liquid paraffin, heavy liquid isoparaffin, α-olefin oligomer, squalane, polyisobutene, polybutene, and the like. Among them, (C13,14) isoparaffin, squalane, isohexadecane, and polyisobutene are preferably used.

[0041] In the composition containing an acrylamide compound, a nonionic surfactant, and a hydrocarbon oil, the content of the acrylamide compound is preferably 20 to 80% by mass, more preferably 35 to 70% by mass, based on the total amount of the composition.

[0042] In the above composition, the content of the nonionic surfactant is preferably 0.5 to 15% by mass, more preferably 2 to 10% by mass, based on the total amount of the composition.

[0043] In the above composition, the content of the hydrocarbon oil is preferably 10 to 50% by mass, more preferably 20 to 35% by mass, based on the total amount of the composition.

[0044] Commercially available products can be used as the composition containing such an acrylamide compound, a nonionic surfactant, and a hydrocarbon oil. For example, SEPIGEL 305 (polyacrylamide, (C13,14) isoparaffin, laureth-7, water), SIMULGEL EG QD ((sodium acrylate / sodium acryloyldimethyltaurine) copolymer, isohexadecane, polysorbate 80, water), SIMULGEL FL ((hydroxyethyl acrylate / sodium acryloyldimethyltaurine) copolymer, isohexadecane, polysorbate 60, water), SIMULGEL NS ((hydroxyethyl acrylate / sodium acryloyldimethyltaurine) copolymer, squalane, polysorbate 60, water), SEPIPLUS S ((hydroxyethyl acrylate / sodium acryloyldimethyltaurine) copolymer, polyisobutene, PEG-7 trimethylolpropane coconut oil alkyl ether, water), SEPIPLUS 265 ((acrylamide / ammonium acrylate) copolymer, polyisobutene, polysorbate 20, water), SIMULGEL 600 ((acrylamide / sodium acryloyldimethyltaurine) copolymer, isohexadecane, polysorbate 80, water), SEPIPLUS 400 (polyacrylate-13, polyisobutene, polysorbate 20, water), etc., sold by SEPPIC can be used.

[0045] Among the above compositions, from the viewpoints of the stability of the external preparation for skin of the present invention and the high dispersibility of the microcapsules containing the ultraviolet absorber, a composition containing a (hydroxyethyl acrylate / sodium acryloyldimethyltaurate) copolymer, polyisobutene, and PEG-7 trimethylolpropane coconut oil alkyl ether, or a composition containing polyacrylate-13, polyisobutene, and polysorbate 20 is preferably used.

[0046] As the aqueous thickener for component (B) other than the composition containing the above acrylamide compound, nonionic surfactant, and hydrocarbon oil, commercially available products can be used. For example, Acpec HU C2002 (bisstearyl PEG / PPG-8 / 6 (SMDI / PEG-400) copolymer) manufactured by Sumitomo Seika Chemicals Co., Ltd., Labol Gum GS-C (xanthan gum) manufactured by DSP Gokyo Food & Chemical Co., Ltd., etc. can be used.

[0047] The content of the aqueous thickener of component (B) in the external preparation for skin of the present invention is preferably 0.1 to 5% by mass, more preferably 0.5 to 3% by mass, based on the total amount of the external preparation for skin. When the content of component (B) is less than this, the dispersibility of the microcapsules containing the ultraviolet absorber may be insufficient, and when it is more than this, the usability such as stickiness and poor skin feel may be impaired when applied to the skin.

[0048] The external preparation for skin of the present invention can contain water in addition to the above components (A) and (B). Furthermore, as long as the effects and stability as an external preparation for skin are not impaired, other components usually used in external preparations for skin can be widely blended according to the intended use.

[0049] In addition to the components (A) and (B) and water, components commonly used in topical skin preparations, such as oily agents, solid or semi-solid oils, surfactants, high molecular compounds, humectants, skin lightening agents, feel improvers, pharmaceuticals, ultraviolet absorbers not encapsulated in the microcapsules of component (A), proteins, protein hydrolysates or their derivatives, amino acids or their derivatives, antioxidants, sequestering agents, pH adjusters, preservatives, pigments, colorants, fragrances, etc. can be appropriately formulated.

[0050] As the oil agent, there is no particular limitation as long as it is liquid at 25°C and is usually used in cosmetics, and any of them can be used. Regardless of its volatility, non-volatility, or origin such as animal oil, vegetable oil, or synthetic oil, examples of oil agents include hydrocarbon oils, fats and oils, ester oils, fatty acids, triacylglycerols, higher alcohols, silicone oils, fluorine-based oils, lanolin derivatives, etc. Specifically, for example, hydrocarbon oils such as (C13-15) alkane, (C15-19) alkane, (C18-21) alkane, (C21-28) alkane, liquid paraffin, heavy liquid isoparaffin, α-olefin oligomer, squalane, polyisobutylene, polybutene, and the hydrocarbon oils exemplified as those contained in the composition of component (B); fats and oils such as olive oil, castor oil, macadamia nut oil; ester oils such as jojoba oil, diisobutyl adipate, 2-hexyldecyl adipate, di-2-heptylundecyl adipate, alkyl glycol monoisostearate, isocetyl isostearate, trimethylolpropane triisostearate, ethylene glycol di-2-ethylhexanoate, cetyl 2-ethylhexanoate, neopentyl glycol di-2-ethylhexanoate, trimethylolpropane tri-2-ethylhexanoate, pentaerythritol tetra-2-ethylhexanoate, cetyl 2-ethylhexanoate, oleyl oleate, octyldodecyl oleate, decyl oleate, neopentyl glycol dicaprate, triethyl citrate, 2-ethylhexyl succinate, isocetyl stearate, butyl stearate, diisopropyl sebacate, di-2-ethylhexyl sebacate, cetyl lactate, myristyl lactate, isopropyl palmitate, 2-ethylhexyl palmitate, 2-hexyldecyl palmitate, 2-heptylundecyl palmitate, dipentaerythritol fatty acid ester, isononyl isononanoate, isotridecyl isononanoate, isopropyl myristate, isopropyl palmitate, 2-octyldodecyl myristate, 2-hexyldecyl myristate, myristyl myristate, hexyldecyl dimethyloctanoate, ethyl laurate, hexyl laurate, 2-ethylhexyl methoxycinnamate, diisostearyl malate;Glyceryl triisooctanoate, glyceryl triisostearate, diglyceryl diisostearate, diglyceryl triisostearate, diglyceryl tetraisostearate, decaglyceryl decaisostearate, glyceryl triisopalmitate, glyceryl trimyristate, diglyceryl myristate isostearate, tritridecyl trimellitate, glyceryl tri(caprylic acid / capric acid), and other triglyceride fatty acids; Amino acid-based oils such as N-lauroyl-L-glutamic acid 2-octyldodecyl ester and N-lauroyl-L-glutamic acid di(phytostearyl·2-octyldodecyl); Fatty acids such as isostearic acid and oleic acid; Higher alcohols such as oleyl alcohol and isostearyl alcohol; Cyclic silicone oils such as cyclotetrasiloxane, cyclopentasiloxane, and cyclohexasiloxane; Chain silicone oils such as dimethylpolysiloxane, methylphenylpolysiloxane, alkoxy-modified organopolysiloxane, and fluorine-modified silicone; Fluorine-based oils such as perfluoropolyether; Lanolin derivatives such as lanolin, lanolin acetate, isopropyl lanolin fatty acid, and lanolin alcohol. These can be used alone or in combination of two or more.;

[0051] Examples of solid or semi-solid oils include fats and oils such as Theobroma grandiflorum seed butter, mango seed butter, cocoa butter, palm oil, palm kernel oil, coconut oil, shea butter, Shorea stenoptera butter, African mango nut butter, avocado butter, Sassafras randaiense seed butter, Astrocaryum murumuru butter, Astrocaryum murumuru seed butter, Astrocaryum tucuma seed butter, Garcinia indica seed butter, Tritillaria emetica seed butter, Bassia latifolia seed butter, Garcinia indica seed butter, hydrogenated cocoa butter, (macadamia seed oil / hydrogenated macadamia seed oil) esters, and milk fat.;

[0052] Examples of the surfactant include anionic surfactants such as higher fatty acid soap, polyoxyethylene alkyl ether sulfate, acyl-N-methyl taurine salt, N-acyl amino acid salt, alkyl phosphate ester salt; cationic surfactants such as alkyl trimethyl ammonium chloride, dialkyl dimethyl ammonium chloride, fatty acid amide alkyl amine; amphoteric surfactants such as alkyl dimethyl amino acetic betaine, alkyl amide amino acetic betaine, 2-alkyl-N-carboxy-N-hydroxy imidazolinium betaine; nonionic surfactants such as polyglycerin fatty acid ester, polyoxyalkylene glycol fatty acid ester, sorbitan fatty acid ester, sorbitol fatty acid ester, polyoxyalkylene alkyl ether, polyether-modified silicone, alkyl polyglucoside, and nonionic surfactants exemplified as those contained in the composition of the component (B).

[0053] Examples of the high molecular compound include carboxyvinyl polymer, sodium carboxymethyl cellulose, polyvinyl alcohol, high molecular dimethyl polysiloxane, gum arabic, tragacanth gum, carob gum, guar gum, pectin, agar, quince seed, starch, algin colloid, dextran, succinoglucan, collagen, gelatin, casein, albumin, carboxymethyl starch, methyl cellulose, ethyl cellulose, methyl hydroxypropyl cellulose, carboxymethyl cellulose, hydroxymethyl cellulose, hydroxypropyl cellulose, nitrocellulose, sodium cellulose sulfate, sodium carboxymethyl cellulose, sodium alginate, polyvinyl methyl ether, sodium polyacrylate, acrylic acid compounds such as polyethylene acrylate, cationic polymers, and acrylamide compounds exemplified as those contained in the composition of the component (B).

[0054] Examples of the acrylic acid compound include (acrylic acid / acryloyldimethyltaurine / dimethylacrylamide) copolymer, (acryloyldimethyltaurine ammonium / vinylpyrrolidone) copolymer, (acryloyldimethyltaurine ammonium / behenes-25 methacrylate) copolymer, (acryloyldimethyltaurine ammonium / steares-25 methacrylate) copolymer, sodium polyacrylate, polyethylene acrylate, polyacrylate cross polymer-6, (acrylamidopropyltrimonium chloride / acrylates) copolymer, (acrylates / alkyl acrylate (C10-30)) cross polymer, (acrylates / steares-20 methacrylate) copolymer, (acrylates / behenes-25 methacrylate) copolymer, (acrylates / steares-20 itaconate) copolymer, steares-10 allyl ether / acrylates copolymer, carboxyvinyl polymer, and the like.

[0055] Examples of the humectant include glycerin, propylene glycol, maltitol, sorbitol, 1,3-butylene glycol, sodium lactate, polyethylene glycol, sodium pyrrolidone carboxylate, sodium hyaluronate, and the like.

[0056] Examples of the whitening agent include ellagic acid, chamomile extract, licorice extract, lucinol, rosemary extract, arbutin, tranexamic acid, potassium 4-methoxysalicylate, ascorbic acid, ascorbic acid glucoside, ascorbic acid derivatives such as ascorbic acid magnesium phosphate, and the like.

[0057] Examples of the feel improver include amylopectin (amylose), acylated amino acid, polymethyl methacrylate, boron nitride, silica, alumina, aluminum hydroxide, metal soap, silicone powder, polymethyl methacrylate, dimethylsilylated silica, and the like.

[0058] Examples of the agent include an anti-rough skin agent or an anti-inflammatory agent. Examples of the anti-rough skin agent or anti-inflammatory agent include dipotassium glycyrrhizinate, stearyl glycyrrhetinate, methyl salicylate, pyridoxine hydrochloride, allantoin, sea salt, Sophora flavescens extract, Aloe extract, Gardenia jasminoides Ellis extract, Chamomilla recutita extract, Glycyrrhiza glabra extract, Phellodendron amurense Rupr. extract, Zingiber officinale Rosc. extract, Coptis chinensis Franch. extract, Rheum palmatum L. extract, Gentiana scabra Bunge extract, Cordyceps sinensis extract, Paeonia suffruticosa Andr. extract, Rehmannia glutinosa Libosch. extract, Ganoderma lucidum Karst. extract, Prunus mume Sieb. et Zucc. leaf extract, Sasa kurilensis (Rupr.) Makino extract, Cnidium officinale Makino extract, Malus sieboldii (Regel) Rehder extract, Prunus persica (L.) Batsch. extract, Ligustrum lucidum Ait. extract, Mentha piperita L. extract, Symphytum officinale L. extract, Arnebia euchroma (Royle) Johnst. extract, Abelmoschus manihot (L.) Medicus extract, Veratrum nigrum L. extract, etc. In addition, hair growth agents, acne agents, dandruff / itching agents, body odor prevention agents, etc. can also be mentioned as agents.

[0059] As the ultraviolet absorber not encapsulated in the microcapsules of component (A), the ultraviolet absorber encapsulated in the microcapsules may be used, and specific examples include those exemplified as the ultraviolet absorber encapsulated in the microcapsules of component (A).

[0060] Examples of the protein, protein hydrolyzate or its derivative include proteins such as milk protein, silk protein, wheat protein, rice protein, pea protein, collagen, keratin, soybean, sesame, conchiolin, marine collagen, etc., hydrolyzates of these, or acylated, silylated, cationized, alkyl ester derivatives of protein hydrolyzates.

[0061] Examples of amino acids or their derivatives include amino acids such as glycine, alanine, valine, leucine, isoleucine, serine, threonine, phenylalanine, arginine, lysine, asparagine, aspartic acid, glutamine, glutamic acid, cystine, cysteine, methionine, tryptophan, proline, histidine, etc., and acylated, alkylated, glycerylated, esterified derivatives thereof, etc.

[0062] Examples of antioxidants include, for example, sodium pyrosulfite, vitamin E or its derivatives, tannin, BHT (butylhydroxytoluene), etc.

[0063] Examples of sequestering agents include, for example, sodium edetate, phosphoric acid, etidronic acid, etc.

[0064] Examples of pH adjusters include, for example, lactic acid, citric acid, glycolic acid, succinic acid, tartaric acid, malic acid, potassium carbonate, sodium hydrogen carbonate, ammonium hydrogen carbonate, etc.

[0065] Examples of preservatives include 1,2-alkanediols such as 1,2-pentanediol, 1,2-hexanediol, alkyl p-hydroxybenzoates such as methyl paraben, propyl paraben, benzoic acid, sodium benzoate, sorbic acid, potassium sorbate, phenoxyethanol, ethylhexylglycerin, etc. The components used in the above-mentioned normal cosmetics can be used alone or in combination of two or more.

[0066] The external preparation for skin of the present invention is preferably used in various dosage forms such as cream, emulsion, gel, liquid, etc. As a product form, it can also be used as an external preparation for skin care including sunscreen cosmetics, or as a makeup cosmetic such as a base having a sunscreen effect, foundation, etc.

Example

[0067] Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to the examples. Note that all numerical values described in the tables of the examples are mass % based on the total mass of the external preparation for skin.

[0068] Examples 1 to 8 and Comparative Examples 1 to 4: Microcapsule aqueous dispersion containing an ultraviolet absorber After mixing the aqueous thickener and water described in Tables 1 and 2, microcapsules containing an ultraviolet absorber (Silasoma MEA manufactured by Seiwa Kasei Co., Ltd.) were added, and the mixture was stirred with a disper (1500 rpm) to prepare a microcapsule aqueous dispersion containing an ultraviolet absorber.

[0069] [Evaluation of stability and dispersibility] The microcapsule aqueous dispersion containing an ultraviolet absorber prepared above was stored in a thermostat at 25°C and 50°C for 4 weeks, and the stability and the dispersibility of the capsules were evaluated according to the following evaluation criteria. Viscosity measurement was performed using a Brookfield LVT viscometer. The results are shown in Tables 1 and 2. Stability: 〇: The viscosity change was ±20% or less compared to immediately after preparation. △: The viscosity change was more than ±20% compared to immediately after preparation. ×: Aggregation or precipitation of the capsules was observed. Dispersibility: 〇: The capsules were uniformly dispersed. △: Some of the capsules tended to aggregate and grow larger. ×: Aggregation or precipitation of the capsules was observed.

[0070] [Table 1] In Table 1, *1 was formulated as Silasoma MEA (trade name, manufactured by Seiwa Kasei Co., Ltd., containing 60% by mass of microcapsules having polysilicon-14 as a wall material and encapsulating ethylhexyl methoxycinnamate and t-butyl methoxydibenzoylmethane, and 40% by mass of water). *2 was formulated as SEPIGEL 305, *3 was formulated as SEPIGEL EG QD, *4 was formulated as SIMULGEL NS, *5 was formulated as SEPIPLUS S, *6 was formulated as SEPIPLUS 400, and *7 was formulated as SIMULGEL FL (all are trade names, all manufactured by SEPPIC). *8 is the label gum GS-C (trade name) manufactured by DSP Gokyo Hood & Chemical Co., Ltd., and *9 is Acpec HU C2002 (trade name) manufactured by Sumitomo Seika Chemicals Co., Ltd.

[0071]

Table 2

[0072] From the results shown in Tables 1 and 2, in the case of the microcapsule aqueous dispersion containing an ultraviolet absorber of Examples 1 to 8 in which an acrylamide-based compound, a nonionic surfactant, and a hydrocarbon oil were contained, and bisstearyl PEG / PPG-8 / 6 (SMDI / PEG-400) copolymer or xanthan gum was blended as a thickener, it was clear that the stability and dispersibility were superior compared to Comparative Examples 1 to 3 in which other thickeners were blended. Also, compared to Comparative Example 4 in which only an acrylamide-based compound was blended as a thickener, it was clear that when a composition containing an acrylamide-based compound, a nonionic surfactant, and a hydrocarbon oil, which contains the same acrylamide-based compound, was blended, the stability and the dispersibility of the capsules were superior.

[0073] Examples 9 and 10: Aqueous gels The components (A) listed in Table 3 were mixed, component (B) was added, and the mixture was stirred with a disperser (2000 rpm) for 3 minutes. In Example 9, component (C) was subsequently added and stirred with a disperser (4000 rpm) for 1 minute. Further, component (D) was added and stirred with a disperser (3000 rpm) for 1 minute to prepare an aqueous gel. The prepared aqueous gel was evaluated for stability and dispersibility in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 4.

[0074]

Table 3

[0075] As shown by the results in Table 3, it was revealed that the aqueous gels prepared in Examples 9 and 10 were excellent in stability and dispersibility of the capsules.

Claims

【Claim 1】 (A)A structural unit U represented by the following general formula (Ia), (Ib) or (Ic): 【Chemical 1】 [In the formula, R ２ represents an alkyl group having 1 to 20 carbon atoms, and each R ２ may be the same or different from each other.], and a structural unit W represented by the following general formula (Id) or (Ie): 【Chemical Formula 2】 [In the formula, R １ represents an alkyl group having 1 to 3 carbon atoms, each R １ may be the same or different, and A is a divalent group that binds Si and N, and is —CH ２ —, —CH ２ CH ２ —, —CH ２ CH ２ CH ２ —, *—(CH ２ ) ３ OCH ２ CH(OH)CH ２ — and *—(CH ２ ) ３ OCOCH ２ CH ２ — (* represents the side that binds to Si), and represents at least one group selected from the group consisting of, E represents a residue obtained by removing one primary amino group from a polypeptide or α-amino acid having a number average molecular weight of 100 to 50,000] is a silylated peptide / silane compound copolymer or a silylated amino acid / silane compound copolymer having a copolymer as a wall film, an encapsulated microcapsule encapsulating an ultraviolet absorber, and (B)An aqueous thickener which is a composition containing an acrylamide compound selected from (hydroxyethyl acrylate / acryloyldimethyltaurine Na) copolymer and polyacrylate-13, a nonionic surfactant, and a hydrocarbon oil A topical skin preparation characterized by containing the same.

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