Oil-in-water type skin external preparation

Abstract

To provide an oil-in-water type skin external preparation that exhibits high transparency after application and possesses good feel in use and stability by combined use of specific components.SOLUTION: An oil-in-water type skin external preparation contains the following (A) to (C): (A) cellulose nanofiber, (B) sucrose fatty acid ester and (C) triethoxycaprylylsilane-treated powder.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an oil-in-water type external skin preparation. [Background technology]

[0002] When considering compositions that can be used as topical skin preparations, technological developments are being made to increase added value, such as by combining various ingredients. However, when a large amount of metal oxide is added, there are problems such as the topical skin preparation not being transparent when applied to the skin (leaving a white cast) or the metal oxide causing a squeaky or sticky feeling. Furthermore, oil-in-water emulsion compositions used as topical skin preparations have problems with emulsion stability, such as the tendency for precipitation or sedimentation to occur over time. Intensive research is being conducted every day to solve these problems.

[0003] Patent Document 1 describes a sunscreen cosmetic that is transparent and suppresses stickiness by incorporating squalane. Patent Document 2 describes an oil-in-water emulsion cosmetic that has a lamellar structure, thereby providing excellent UV protection, while also having excellent emulsion stability, a fresh feeling upon application, and good compatibility with the skin. However, the transparency, fresh feeling, lack of squeaky feeling, and emulsion stability upon application are insufficient, leaving room for improvement. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6445787 [Patent Document 2] Japanese Patent Publication No. 2022-72130 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide an oil-in-water type external skin preparation that is highly transparent after application, has a good feel when used, and is stable, by using specific ingredients in combination. [Means for solving the problem]

[0006] The object of the present invention is to provide an oil-in-water type external skin preparation containing the following (A) to (C): (A) Cellulose nanofiber (B) Sucrose fatty acid ester (C) Triethoxycaprylylsilane treated powder [Effects of the Invention]

[0007] The oil-in-water type external skin preparation of the present invention exhibits the effects of high transparency after application, good feel in use, and stability due to the combined use of specific ingredients. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described. Each component will be described below.

[0009] [Cellulose nanofiber] The cellulose nanofibers (A) used in the present invention are not particularly limited as long as they are those typically incorporated into topical skin preparations. It is preferable to use cellulose nanofibers obtained by defibrating cellulose fibers to the nano level. Examples of the size of the cellulose nanofibers include fibrous substances with an average fiber width of 2 to 5 nm and a fiber length of 100 nm or more. In the present invention, the fiber width is preferably 10 nm or less, and more preferably 5 nm or less.

[0010] Examples of cellulose fibers include fibers separated from plant fibers such as plant-derived pulp, wood, cotton, hemp, bamboo, cotton, kenaf, hemp, jute, banana, coconut, cassava, seaweed, tea leaves, agricultural waste, and waste paper.

[0011] The cellulose nanofibers according to this embodiment include those made from plant-derived cellulose microfibrils (or their constituent fibers), as well as bacterial cellulose produced by microorganisms such as acetic acid bacteria, lignocellulose nanofibers, and cellulose nanofibers obtained by electrospinning. Lignocellulose nanofibers are cellulose nanofibers containing lignin (lignin-coated cellulose nanofibers). Cellulose nanofibers obtained by electrospinning are cellulose nanofibers obtained by spinning a solution of a cellulose-based material while applying a voltage.

[0012] The cellulose nanofibers according to this embodiment may be modified. The mode of modification can be selected depending on the purpose, and examples include hydrophobization and the introduction of functional groups. Specific modifications include acid modification [e.g., carboxylation (e.g., carboxymethylation), phosphorylation, sulfuric acid or sulfonation], ester or acyl modification (e.g., acetylation), amine modification, amide modification, epoxy modification, and fluorene modification. The acid group or amine group may form a salt.

[0013] Cellulose nanofibers can be obtained by mechanical defibration treatment. Preferably, before the defibration treatment, cellulose is oxidized using TEMPO (2,2,6,6-tetramethylpiperidine-1-oxy radical) as a catalyst to introduce carboxyl groups (sodium carboxylate) onto the surface of the cellulose microfibrils. This preliminary treatment allows the cellulose to be defibrated into microfibril units by a milder mechanical defibration treatment, taking advantage of the repulsive force of the electric double layer.

[0014] Examples of commercially available cellulose nanofibers include Rheocrysta C-2SP (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and Cellenpia CS-01C (manufactured by Nippon Paper Industries Co., Ltd.).

[0015] The cellulose nanofibers are preferably blended in an amount of 0.1 to 20% by mass, more preferably 1 to 15% by mass, based on the total amount of the oil-in-water skin topical preparation. If the blending amount is less than 0.1% by mass, sufficient emulsion stabilization effect may not be obtained.

[0016] In terms of emulsion stability, it is preferable to use cellulose nanofibers in combination with a polysaccharide thickener other than cellulose nanofibers in the oil-in-water topical skin preparation of the present invention. Examples of polysaccharide thickeners include crystalline cellulose, cellulose gum, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose, gellan gum, carrageenan, guar gum, locust bean gum, gum arabic, xanthan gum, dextran, and succinoglucan. One or more of these can be selected and used in the present invention. From the standpoint of effectiveness, it is preferable to use one or two selected from gum arabic and xanthan gum.

[0017] When a polysaccharide thickener is added, the amount added is preferably 0.01 to 10% by mass, more preferably 0.01 to 5% by mass, based on the total amount of the oil-in-water type external skin preparation.

[0018] [Sucrose fatty acid esters] Examples of the sucrose fatty acid ester (B) used in the present invention include sucrose laurate, sucrose myristate, sucrose palmitate, sucrose stearate, sucrose oleate, sucrose distearate, and sucrose coconut fatty acid. One or more of these can be selected and incorporated into the present invention. Among these, sucrose coconut fatty acid is particularly preferred from the viewpoint of powder dispersion stability. Any sucrose that is typically incorporated into topical skin preparations is not particularly limited, and commercially available sucrose fatty acid esters can also be used. Examples of commercially available sucrose fatty acid esters include TEGOSOFT LSE 65 K Soft MB (manufactured by Evonik Operations GmbH) and SP Alacel 2121 MBAL (manufactured by Croda Japan).

[0019] The sucrose fatty acid ester is preferably blended in an amount of 0.1 to 5% by mass, more preferably 0.5 to 4% by mass, and particularly preferably 1 to 3% by mass, based on the total amount of the oil-in-water skin topical preparation. If the amount is less than 0.1% by mass, sufficient emulsion stabilization effect may not be obtained.

[0020] In terms of emulsion stability, it is preferable to use a sucrose fatty acid ester and a sorbitan fatty acid ester in combination in the oil-in-water skin topical preparation of the present invention. Examples of sorbitan fatty acid esters include sorbitan monolaurate, sorbitan monomyristate, sorbitan monopalmitate, sorbitan monostearate, and sorbitan monobehenate, and among these, sorbitan monostearate is preferably used.

[0021] When a sucrose fatty acid ester and a sorbitan fatty acid ester are used in combination, the blending amount is 1 to 50 parts by mass, preferably 10 to 30 parts by mass, of sorbitan fatty acid ester per part by mass of sucrose fatty acid ester. The HLB value of the mixture of sucrose fatty acid ester and sorbitan fatty acid ester is preferably adjusted to 4 to 7, preferably 5 to 7.

[0022] [Triethoxycaprylylsilane treated powder] The triethoxycaprylylsilane used in the triethoxycaprylylsilane-treated powder (C) used in the present invention is not particularly limited as long as it is one that is usually incorporated into external skin preparations.

[0023] The powder to be surface-coated with triethoxycaprylylsilane is not particularly limited, but it is particularly preferred to use powders for cosmetics.Such powders include titanium oxide, red iron oxide, yellow iron oxide, black iron oxide, zinc oxide, cerium oxide, manganese violet, cobalt violet, chromium oxide, chromium hydroxide, cobalt titanate, ultramarine, Prussian blue, magnesium oxide, zirconium oxide, talc, kaolin, sericite, muscovite, phlogopite, synthetic mica, lepidolite, biotite, vermiculite, silica, calcium carbonate, magnesium carbonate, magnesium silicate, aluminum silicate, barium silicate, calcium silicate, barium sulfate, calcium sulfate, calcium phosphate, hydroxyapatite, boron nitride, pearl pigments, inorganic pigments such as bismuth oxychloride, Red No. 3, Red No. 10, Red No. 106, Red No. 201, Red No. 202, Red No. 204, Red No. 205, Red No. 220, Examples of suitable organic pigments include Red No. 226, Red No. 227, Red No. 228, Red No. 230, Red No. 401, Red No. 405, Red No. 505, Yellow No. 4, Yellow No. 5, Yellow No. 202, Yellow No. 203, Yellow No. 205, Yellow No. 401, Orange No. 201, Orange No. 203, Orange No. 204, Orange No. 205, Orange No. 206, Orange No. 207, Blue No. 1, Blue No. 2, Blue No. 201, Blue No. 404, Green No. 3, Green No. 201, Green No. 204, and Green No. 205; natural pigments such as chlorophyll and β-carotene; metal soaps such as zinc myristate, calcium palmitate, and aluminum stearate; and organic powders such as nylon powder, cellulose powder, polyethylene powder, polymethyl methacrylate powder, polystyrene powder, acrylic powder, and silicone powder. From the viewpoint of the effects of the present invention, it is preferable to use one or two selected from titanium oxide and zinc oxide.

[0024] The mass ratio of triethoxycaprylylsilane used in the surface coating treatment of the powder is preferably 0.1 to 50 parts by mass, more preferably 0.1 to 30 parts by mass, relative to the powder to be treated. If the mass ratio is less than 0.1 part by mass, sufficient emulsion stabilization effect may not be obtained.

[0025] Next, a method for producing the triethoxycaprylylsilane-treated powder of the present invention will be described. The surface coating method is not particularly limited, and surface coating can be performed by a conventional method. For example, the pigment powder to be surface-coated is stirred in an appropriate mixer, and a solution of a polyhydric alcohol, either directly or in an alcohol such as ethanol, isopropyl alcohol, or isobutanol; a hydrocarbon organic solvent such as toluene, n-hexane, or cyclohexane; or a polar organic solvent such as acetone, ethyl acetate, or butyl acetate, is added dropwise or by spraying. After stirring, the organic solvent is completely evaporated off if necessary. The powder is then pulverized and heated to 80 to 200°C for aging, thereby carrying out the surface coating treatment.

[0026] The equipment used to mix and disperse the powder can be selected appropriately depending on the concentration and viscosity of the solution. Suitable examples include a reaction vessel with a stirring blade, a blender such as a disper, a Henschel mixer, a Lödige mixer, a kneader, a V-type mixer, a roll mill, a bead mill, or a twin-screw kneader, and a spray-drying method in which an aqueous solution and pigment are sprayed into heated air to remove moisture all at once. Furthermore, when pulverizing, a conventional pulverizer such as a hammer mill, a ball mill, a sand mill, or a jet mill can be used. Since products of similar quality can be obtained using any of these pulverizers, there is no particular limitation.

[0027] The triethoxycaprylylsilane-treated powder of the present invention is preferably blended in an amount of 0.5 to 90% by mass relative to the total amount of the oil-in-water skin topical preparation. If the amount is less than 0.5% by mass, sufficient emulsion stabilization effect may not be obtained. On the other hand, if the amount of the composite powder is blended in an amount exceeding 90% by mass, formulation tends to become difficult.

[0028] The oil-in-water topical skin preparation of the present invention may contain one or more hydrophilic polymers selected from acrylic polymers and urethane polymers. The acrylic polymer may be any polymer having an acrylic group structure and suitable for use in typical topical skin preparations, and is not particularly limited. Examples include (acrylates / C10-30 alkyl acrylate) crosspolymer, carbomer, (sodium acrylate / acryloyldimethyltaurate / dimethylacrylamide) crosspolymer, acrylamido-2-methylpropanesulfonate copolymer, hydroxyethyl acrylate-acryloyldimethyltaurate copolymer, acrylate-acryloyldimethyltaurate copolymer, acrylic acid amide-2-methylpropanesulfonate copolymer, and acryloyldimethyltaurate-vinylpyrrolidone copolymer.

[0029] Commercially available examples of (acrylates / C10-30 alkyl acrylate) crosspolymers include PEMULEN TR-1, PEMULEN TR-2, Carbopol 1342, Carbopol ETD2020, Carbopol ULTREZ-20, and Carbopol ULTREZ-22 (all manufactured by Lubrizol Corporation), AQUPEC HV-501ER, AQUPEC HV-701EDR, AQUPEC HV-801ERK, AQUPEC HV-803ERK, AQUPEC SW-703ER, and AQUPEC SR-705ER (all manufactured by Sumitomo Seika Chemicals).

[0030] Commercially available examples of carbomers include Carbopol 934, Carbopol 940, Carbopol 941, Carbopol ETD2050 (all manufactured by Lubrizol Corporation), AQUPEC HV-501E, AQUPEC HV-505E, AQUPEC HV-505ED, AQUPEC HV-801EG-300, AQUPEC HV-805EG-300 (all manufactured by Sumitomo Seika Chemicals), Hiviswako 103, Hiviswako 104, and Hiviswako 105 (all manufactured by Wako Pure Chemical Industries, Ltd.).

[0031] Commercially available examples of (sodium acrylate / acryloyldimethyltaurate / dimethylacrylamide) crosspolymer, acrylamide-2-methylpropanesulfonate copolymer, hydroxyethyl acrylate-acryloyldimethyltaurate copolymer, acrylate-acryloyldimethyltaurate copolymer, acrylic acid amide-2-methylpropanesulfonate copolymer, and acryloyldimethyltaurate-vinylpyrrolidone copolymer include the SIMULGEL series and the SEPINOV series (all manufactured by SEPIC).

[0032] The urethane-based polymer is not particularly limited as long as it is a water-soluble urethane-based polymer that can be incorporated into typical topical skin preparations. A preferred urethane-based polymer is a hydrophobically modified polyether urethane. Examples of hydrophobically modified polyether urethanes include polyethylene glycol (PEG)-240 / decyltetradeceth-20 / hexamethylene diisocyanate (HDI) copolymers. A commercially available example of this PEG-240 / decyltetradeceth-20 / HDI copolymer is Adekanol GT-700 (manufactured by ADEKA Corporation).

[0033] The oil-in-water topical skin preparation of the present invention contains a liquid oily component due to its formulation. Such liquid oily component can be any component commonly used in topical skin preparations and liquid at 25°C, without any particular limitation. Examples of such liquid oils include rapeseed oil, avocado oil, almond oil, olive oil, kukui nut oil, sesame oil, wheat germ oil, rice germ oil, rice bran oil, rice oil, safflower oil, sunflower oil, soybean oil, evening primrose oil, corn oil, rapeseed oil, persic oil, palm oil, palm kernel oil, castor oil, jojoba oil, grapeseed oil, macadamia nut oil, meadowhoo oil, menjitsu oil, coconut oil, and other vegetable oils; Animal oils such as liquid horse oil, mink oil, and liquid lanolin; linear or branched hydrocarbon oils such as liquid paraffin, light isoparaffin, squalane, squalene, etc.; Higher fatty acids such as oleic acid and isostearic acid; higher alcohols such as isostearyl alcohol, octyldodecanol, and hexyldecanol; alkyl glyceryl ethers such as isostearyl glyceryl ether; ester oils of straight-chain fatty acids with lower alcohols, such as isopropyl myristate, butyl myristate, isopropyl palmitate, ethyl stearate, butyl stearate, ethyl oleate, ethyl linoleate, and isopropyl linoleate; ester oils of straight-chain fatty acids and straight-chain higher alcohols, such as cetyl caprate, hexyl laurate, decyl myristate, myristyl myristate, cetyl myristate, cetyl palmitate, stearyl stearate, decyl oleate, and oleyl oleate; Ester oils of straight-chain fatty acids and branched-chain alcohols, such as perilla laurate, isotridecyl myristate, isocetyl myristate, isostearyl myristate, octyldodecyl myristate, 2-ethylhexyl palmitate, isocetyl palmitate, isostearyl palmitate, 2-ethylhexyl stearate, isocetyl stearate, isodecyl oleate, octyldodecyl oleate, and octyldodecyl ricinoleate; Ester oils of branched chain fatty acids and lower alcohols, such as ethyl isostearate and isopropyl isostearate; Ester oils of branched fatty acids and linear higher alcohols, such as cetyl 2-ethylhexanoate, cetostearyl 2-ethylhexanoate, stearyl 2-ethylhexanoate, hexyl isostearate, and 2-hexyldecyl isostearate; Ester oils of fatty acids and polyhydric alcohols, such as ethylene glycol dioctanoate, ethylene glycol dioleate, propylene glycol dicaprylate, propylene glycol dicaprylate-caprate, propylene glycol dicaprate, dipropylene glycol dioleate, neopentyl glycol dicaprate, neopentyl glycol dioctanoate, glyceryl tricaprylate, glyceryl tri-2-ethylhexanoate, glyceryl tri-(caprylate-caprate), glyceryl triisopalmitate, glyceryl isostearate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, pentaerythritol tetra-2-ethylhexanoate, pentaerythritol tetraisostearate, and pentaerythritol tetra-2-ethylhexanoate; Ester oils of branched chain fatty acids and branched chain alcohols, such as octyldodecyl neopentanoate, isocetyl octanoate, isostearyl octanoate, 2-ethylhexyl isopelargonate, hexyldecyl dimethyloctanoate, octyldodecyl dimethyloctanoate, 2-ethylhexyl isopalmitate, isocetyl isostearate, isostearyl isostearate, octyldodecyl isostearate, and isononyl isononanoate; ester oils having a hydroxyl group, such as lauryl lactate, myristyl lactate, cetyl lactate, octyldodecyl lactate, trioctyl citrate, triisocetyl citrate, trioctyldodecyl citrate, and diisostearyl malate; dibasic acid ester oils such as dioctyl succinate, diisopropyl adipate, diisobutyl adipate, dioctyl adipate, diethyl sebacate, diisopropyl sebacate, and dioctyl sebacate; Silicone oils such as dimethylpolysiloxane, dimethylcyclopolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, and higher alcohol-modified silicone oil; Examples include fluorine oils such as fluoropolyether and perfluoroalkyl ether silicone, etc. In the present invention, these liquid oils can be used alone or in combination of two or more.

[0034] In the oil-in-water type topical skin preparation of the present invention, it is preferable that a powder is dispersed in the oil phase. Therefore, in order to improve the dispersion stability of the triethoxycaprylylsilane-treated powder in the present invention, it is preferable to use one or more selected from polyglyceryl polyricinoleate, dipentaerythrityl tripolyhydroxy fatty acid, and polyglyceryl diisostearate, and it is most preferable to use polyglyceryl polyricinoleate.

[0035] In addition to the above-mentioned components, the oil-in-water topical skin preparation of the present invention can contain optional components used in ordinary cosmetics and quasi-drugs to the extent that the effects of the present invention are not impaired. Specific examples of such optional components include cosmetic ingredients such as powders other than those mentioned above, oils, surfactants, thickeners, preservatives, fragrances, moisturizers, antioxidants, anti-inflammatory agents, antibacterial agents, and whitening agents.

[0036] The oil-in-water type external skin preparation of the present invention can be prepared by a conventional method.

[0037] The oil-in-water skin external preparation of the present invention can be used in any dosage form, for example, cream, emulsion, or liquid. [Example]

[0038] The present invention will be specifically explained below using examples, but the scope of the present invention is not limited thereto. Oil-in-water type external skin preparations were prepared by a standard method according to the formulations shown in Tables 1 and 2. The blend amounts are in mass % unless otherwise specified.

[0039] [Transparency Assessment] The oil-in-water topical skin preparations according to the Examples and Comparative Examples were applied at a concentration of 2 mg / cm to a Blenderm surgical tape (manufactured by 3M) for SPF measurement. 2After uniformly applying the composition at a ratio of 100%, the composition was left to stand at room temperature for 10 minutes and allowed to dry naturally. The transmittance at 450 nm was then measured using an SPF analyzer (UV-2000S, manufactured by Labsphere). The average value of 5 points x 3 measurements was calculated and evaluated according to the following criteria. The results are shown in Tables 1 and 2. <Judgment criteria> ◎: 80% or more ○: 70% or more but less than 80% ×: Less than 70%

[0040] [Usability evaluation] Three expert sensory evaluators independently used the oil-in-water skin topical preparations of the Examples and Comparative Examples, and evaluated the freshness and smoothness of the skin upon application in accordance with the following criteria. The results are shown in Tables 1 and 2. <Judgment criteria> ◎: Very good ○:Good △: A little bad ×: Bad

[0041] [Emulsion stability evaluation] The prepared oil-in-water skin preparations according to the Examples and Comparative Examples were stored in a thermostatic chamber at 50°C, and the emulsified state was visually observed after one month and evaluated according to the following criteria. The results are shown in Tables 1 and 2. <Judgment criteria> ○: No separation observed, good ×: Separation was observed and not good

[0042] [Table 1]

[0043] [Table 2]

[0044] As shown in Table 1, Examples 1 to 6, which used a combination of cellulose nanofiber, sucrose fatty acid ester, and triethoxycaprylylsilane-treated powder, showed excellent results in all aspects of the transparency, freshness, lack of squeaking, and emulsion stability of the applied surface after application.

[0045] On the other hand, as shown in Table 2, none of Comparative Examples 1 to 4 provided good results.

Claims

[Claim 1] An oil-in-water type external skin preparation containing the following (A) to (C): (A) Cellulose nanofiber (B) Sucrose fatty acid ester (C) Triethoxycaprylylsilane-treated powder

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