Gel sheet for skin application

Abstract

To provide gel sheets for skin application in which moisture is retained over time, and a sheet collapses smoothly due to the rubbing of the user while maintaining the strength as a gel sheet, so as to be capable of conforming to the skin.SOLUTION: Provided is a gel sheet for skin application comprising the following components (A) to (C): (A) 0.1 to 20 mass% of at least one selected from alginic acid (salt), fucoidan, agarose, and carrageenan; (B) 0.1 to 40 mass% of an oil agent; and (C) 40 to 90 mass% of polyhydric alcohol, the content of water being 10 mass% or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a gel sheet for application to the skin. [Background technology]

[0002] BACKGROUND ART Cosmetics and pharmaceuticals are known in which a sheet containing a moisturizing ingredient, an active ingredient, or the like is brought into contact with the skin and then removed after a certain period of time, thereby allowing the moisturizing ingredient, the active ingredient, or the like to penetrate into the skin.

[0003] Some of these sheets are made by forming a gel composition into a sheet without using a support such as a nonwoven fabric. In such a form, the gel must be maintained in a sheet shape, and the formed gel must maintain its shape and have a certain degree of strength. Patent Document 1 discloses a topical gel composition for skin application, which comprises a first composition comprising carrageenan and / or xanthan gum, glucomannan and / or gellan gum and / or tamarind gum, and agar; a second composition comprising an organic acid having one or more carboxyl groups and / or a water-soluble polymer having one or more carboxyl groups; a third composition comprising alcohols; and purified water. Sheets obtained from this gel composition are said to have high gel strength and tensile strength. Patent Document 2 also discloses an aqueous topical gel composition using carrageenan / mannan as a base material in combination with gellan gum / agar / agarose.

[0004] Furthermore, Patent Document 3 discloses a gel sheet for application to the skin, which contains 10% by mass or less of polyvinyl alcohol, an acrylic acid polymer, a polyhydric alcohol, a solid / semi-solid oil, and water. Patent Document 3 states that this composition provides excellent moisturizing effect, ease of use, and formability of the sheet. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-50298 [Patent Document 2] JP 2002-87993 A [Patent Document 3] International Publication No. 2019 / 131484 Summary of the Invention [Problem to be solved by the invention]

[0006] Although the technology of Patent Document 1 ensures film strength, it is difficult for the user to apply force, such as by massaging, to blend the sheet into the skin after applying it to the skin. Furthermore, the technology of Patent Document 2 uses a water-based gel sheet, which does not adequately maintain moisturizing properties over time. Furthermore, the technology of Patent Document 3 envisions a method of use in which water is added to blend the ingredients into the skin, but high solubility in water is an issue, necessitating the use of water during use.

[0007] Therefore, an object of the present invention is to provide a gel sheet for application to the skin that maintains its moisture retention over time, maintains its strength as a gel sheet, disintegrates smoothly when rubbed by the user, and can be applied to the skin. [Means for solving the problem]

[0008] The present invention provides a gel sheet for application to the skin, characterized in that it contains the following components (A) to (C): (A) 0.1 to 20% by mass of at least one selected from alginic acid (salt), fucoidan, agarose, and carrageenan, (B) 0.1 to 40% by mass of an oil solution, and (C) 40 to 90% by mass of a polyhydric alcohol, and that the water content is 10% by mass or less. [Effects of the Invention]

[0009] The gel sheet for application to the skin of the present invention maintains its moisture retention over time, and while maintaining its strength as a gel sheet, the gel sheet disintegrates smoothly when rubbed by the user without the need for water, allowing it to fit comfortably on the skin. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments. In this specification, the range "X to Y" includes X and Y and means "X or more and Y or less." Furthermore, unless otherwise specified, operations and measurements of physical properties, etc. are performed under conditions of room temperature (20 to 25°C) and relative humidity of 45 to 55% RH.

[0011] The present invention provides a gel sheet for application to the skin, characterized in that it contains the following components (A) to (C): (A) 0.1 to 20% by mass of at least one selected from alginic acid (salt), fucoidan, agarose, and carrageenan, (B) 0.1 to 40% by mass of an oil, and (C) 40 to 90% by mass of a polyhydric alcohol, and contains 10% by mass or less of water. Hereinafter, the gel sheet for application to the skin will also be referred to simply as a gel sheet. Hereinafter, water will also be referred to as component (D).

[0012] Gel sheets are typically laminated on a release substrate film, and the user peels the gel sheet from the release substrate film and transfers the gel sheet onto the skin. Typically, after a predetermined time has passed, the gel sheet is often peeled off and removed from the skin. On the other hand, when the user applies pressure to the gel sheet on the skin, as if massaging, the gel structure of the gel sheet of the present invention easily collapses and transforms into a cream-like (ointment-like) state. Therefore, the components of the gel sheet can be applied to the skin like a cosmetic cream. Therefore, the gel sheet of the present invention combines the properties of both a so-called face mask and a (cosmetic / pharmaceutical) cream, enabling the effects of both to be achieved.

[0013] Generally, there is a trade-off between the gel strength required to maintain the shape of a gel sheet and the disintegration (ease of crumbling) of the gel structure, making it difficult to achieve both. Furthermore, even if the gel structure is broken by the load of force, if the gel disintegrates in a manner that causes it to break (the gel crumbles), it is necessary to imprint the gel-like substance on the skin, making it difficult to blend into the skin. On the other hand, by adopting the configuration of the present invention, the gel sheet can be smoothly disintegrated by the user's rubbing, becoming creamy and easily blended into the skin, while maintaining the strength of the gel sheet. Furthermore, after leaving the gel sheet on the skin for a certain period of time like a pack, the gel sheet can be broken down to allow the gel sheet components to blend into the skin, thereby enhancing the durability of the moisturizing effect.

[0014] In dynamic viscoelasticity measurement, the gel sheet preferably has a storage modulus G' of 20,000 Pa or less when subjected to 1% strain at 35°C and a frequency of 50 Hz. With a storage modulus G' of 20,000 Pa or less, when the user applies force to the gel sheet (massaging it on the skin), the gel structure easily collapses, becoming creamy and easily absorbed into the skin. For the same reason, the storage modulus G' when subjected to 1% strain at 35°C and 50 Hz is more preferably 10,000 Pa or less. The lower limit of the storage modulus G' when subjected to 1% strain at 50 Hz is not particularly limited, but is typically 1,000 Pa or more.

[0015] Each component will be described below.

[0016] (Component (A): at least one selected from alginic acid (salt), fucoidan, agarose, and carrageenan) Component (A) plays an important role in maintaining the sheet-like structure of the gel sheet and in easily breaking down the gel structure of the gel sheet by hand after application to the skin. Without component (A), the gel structure is difficult to break down even when force is applied by hand, or it breaks down so much that it breaks down, making it difficult to apply to the skin (Comparative Example 1 described below). Alternatively, without component (A), it is difficult to ensure gel strength (Comparative Examples 3 and 4 described below).

[0017] Alginic acid is found in brown algae and is an acidic polysaccharide composed of two uronic acids, mannuronic acid and glucuronic acid. When the carboxyl group of alginic acid combines with sodium ions, it becomes a neutral salt, forming an alginate. Examples of alginate include calcium alginate and sodium alginate.

[0018] Fucoidan is a polysaccharide with sulfate groups, consisting of tens to hundreds of thousands of L-fucose units linked together, and its average molecular weight is generally said to be 100,000 to 30,000,000. Fucoidan is classified into U-fucoidan, F-fucoidan, and G-fucoidan. Generally, U-fucoidan is a sulfate polysaccharide containing glucuronic acid in addition to the basic sugar residue fucose, F-fucoidan is a sulfate polysaccharide composed of the basic sugar residue L-fucose, and G-fucoidan is a sulfate polysaccharide containing galactose in addition to the basic sugar residue L-fucose.

[0019] Agarose is a polysaccharide with a linear structure in which D-galactose and 3,6-anhydro-L-galactose residues are alternately linked via β-(1→4) and α-(1→3) bonds.

[0020] Carrageenan is a polysaccharide extracted from red algae and has a structure in which D-galactose is alternately linked via α-1,3 or β-1,4 bonds. Carrageenan is classified into three types: ι, λ, and κ, depending on the number of sulfate groups and the presence or absence of anhydro bonds. In the present invention, any of the ι (iota), λ (lambda), and κ (kappa) carrageenans can be used.

[0021] Component (A) is preferably at least one selected from alginate, fucoidan, agarose, and carrageenan, and from the standpoint of gel strength and ease of application to the skin (ease of breakdown of the membrane structure), alginate is more preferred, and sodium alginate is particularly preferred.

[0022] The component (A) may be used alone or in combination of two or more types.

[0023] The content of component (A) is 0.1 to 20% by mass. If the content of component (A) is less than 0.1% by mass, the gel structure will not crumble smoothly, making it difficult to achieve a skin-friendly effect. If the content of component (A) exceeds 20% by mass, the gel strength will be too high, making it difficult for the gel structure to crumble even when force is applied by hand, or it will crumble in a ruptured manner, making it difficult to apply to the skin. The content of component (A) is preferably 0.5% by mass or more, and from the viewpoint of gel strength, more preferably 1.0% by mass or more. The content of component (A) is preferably 15% by mass or less, and more preferably 10% by mass or less, as this further improves the gel's crumbling properties, skin compatibility, and sustained moisturizing effect.

[0024] (Component (B): Oil) In this specification, an oil refers to an oil-soluble compound that is insoluble (slightly soluble) in water, such as a substance with a water solubility (1013.25 hPa, 20°C) of less than 2 g / 100 g H2O. The use of an oil can impart a moisturizing effect, which can contribute to improving the moisturizing effect of the gel sheet.

[0025] The oil agent is not particularly limited, but preferably component (B) contains a solid or semi-solid oil agent at 25°C, and more preferably a solid oil agent. A solid or semi-solid oil agent at 25°C increases the film strength of the gel sheet and also contributes to imparting viscosity to the O / W emulsion composition before sheet formation, thereby contributing to improved formability. Furthermore, the inclusion of a solid and / or semi-solid oil agent further improves the durability of the moisturizing effect. Furthermore, a gel sheet can be obtained that is well-adjusted in terms of solubility in water, disintegration due to swelling in water, formability, or a combination thereof.

[0026] The oil agent that is solid or semi-solid at 25° C. is not particularly limited, and examples thereof include hydrocarbon oils, ester oils, higher alcohol oils, ether oils, and silicone oils. One type of oil agent that is solid or semi-solid at 25° C. may be used alone, or two or more types may be used in combination.

[0027] In the present invention, "semi-solid" refers to a substance that has a gel hardness measured using a rheometer (manufactured by Fudo Kogyo Co., Ltd.) (in a penetration test where the specimen storage temperature is 25°C, the needle diameter of the pressure-sensitive shaft (adapter) is 5 mmφ, and the penetration rate is 60 mm / min, the maximum load applied to the pressure-sensitive shaft when the pressure-sensitive shaft is pressed to a depth of 5 mm is less than 13 N, and that does not exhibit fluidity at 25°C. "Solid oil" refers to a substance that has a maximum load of 13 N or more applied to the pressure-sensitive shaft when the pressure-sensitive shaft is pressed to a depth of 5 mm in the above penetration test.

[0028] The oil agent that is solid at 25°C is not particularly limited, but examples thereof include hydrocarbon solid oils such as paraffin wax, ceresin wax, microcrystalline wax, polyethylene wax, ethylene-propylene copolymer, montan wax, and Fischer-Tropsch wax; hydrogenated jojoba oil, beeswax, carnauba wax, candelilla wax, rice wax, eicosene / vinylpyrrolidone copolymer, α-olefin-vinylpyrrolidone copolymer, ester solid oils such as glyceryl tribehenate; higher alcohol solid oils such as stearyl alcohol, cetyl alcohol, lauryl alcohol, behenyl alcohol, and cetostearyl alcohol; and silicone solid oils such as acrylates / behenyl acrylate / dimethicone methacrylate copolymer and acrylates / stearyl acrylate / dimethicone methacrylate. Of these, hydrocarbon solid oils, ester solid oils, and higher alcohol solid oils are preferred.

[0029] Furthermore, the oil agent that is semi-solid at 25°C is not particularly limited, and examples thereof include hydrocarbon semi-solid oils such as petrolatum, dipentaerythrityl hexa(hydroxystearate / stearate / rosinate), dipentaerythrityl (hydroxystearate / stearate / rosinate), dipentaerythrityl hexahydroxystearate, dipentaerythrityl tetra(hydroxystearate / isostearate), and dipentaerythrityl (hydroxystearate / isostearate), hydrogenated castor oil fatty acid esters such as hydrogenated castor oil stearate, hydrogenated castor oil isostearate, and hydrogenated castor oil hydroxystearate, and cholesterol esters such as cholesteryl hydroxystearate. phytosterol fatty acid esters such as sterol fatty acid esters, phytosteryl oleate, and phytosteryl macadamia nut fatty acid; hydrogenated vegetable oils such as hydrogenated coconut oil and hydrogenated palm oil; ester-based semi-solid oils such as phytosteryl / isosteryl / cetyl / stearyl / behenyl dimer dilinoleate, sucrose pentahydroxystearate, di(octyldodecyl / phytosteryl / behenyl) lauroyl glutamate, and bisdiglyceryl polyacyladipate-2; ether-based semi-solid oils such as hydroxyalkyl dimer silinoleyl ether; triglyceride-based semi-solid oils such as tribehenin; and silicone-based semi-solid oils such as dimethicone crosspolymer and (dimethicone / vinyl dimethicone) crosspolymer.

[0030] Among these, from the viewpoint of film strength and moldability, the melting point of the solid oil is preferably 45 to 100°C, more preferably 45 to 70°C. When the melting point is above the lower limit, film formability is good, and when the melting point is below the upper limit, the film structure is likely to collapse when force is applied. It is preferable that the melting points of all the solid oils to be blended are within the above suitable range.

[0031] Considering the above effects, the content of the solid and / or semi-solid oil agent in the gel sheet is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, and even more preferably 1 to 10% by mass.

[0032] As the oil, it is also preferable to use an oil that is liquid at 25°C (hereinafter also referred to as "liquid oil"). The use of a liquid oil can impart a moisturizing effect, which can contribute to improving the moisturizing effect of the gel sheet. In addition, the use of a liquid oil further improves the plasticity of the film. Furthermore, from the viewpoint of forming a gel structure, it is preferable to use a combination of the above-mentioned solid and / or semi-solid oil and a liquid oil.

[0033] The liquid oil refers to an oil that has fluidity at 25°C, and is not particularly limited as long as it is used in cosmetics, etc. Examples of liquid oils at 25°C include, but are not limited to, hydrocarbon oils, fats and oils, ester oils including UV absorbers, fatty acids, higher alcohols, silicone oils, fluorine-based oils, lanolin derivatives, etc., regardless of whether they are volatile or non-volatile and whether they are of animal, vegetable, or synthetic origin. One or more of these can be appropriately selected and used.

[0034] Liquid oils at 25°C include, specifically, oils and fats such as olive oil, castor oil, mink oil, macadamia nut oil, avocado oil, and medusa oil; jojoba oil, diisobutyl adipate, 2-hexyldecyl adipate, di-2-heptylundecyl adipate, alkyl glycol monoisostearate, isocetyl isostearate, trimethylolpropane triisostearate, ethylene glycol di-2-ethylhexanoate, neopentyl glycol di-2-ethylhexanoate, trimethylolpropane tri-2-ethylhexanoate, and the like. Ingredients: propane, 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-heptylun palmitate Decyl, 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 Tri-2-Ethylhexanoate, Glyceryl Tri(Caprylate / Caprate), Glyceryl Tricaprate, Triisostearate Esters of glyceryl tearic acid, diglyceryl diisostearate, diglyceryl triisostearate, diglyceryl tetraisostearate, decaglyceryl decaisostearate, glyceryl triisopalmitate, glyceryl trimyristate, diglyceryl myristate isostearate, tritridecyl trimellitate, N-lauroyl-L-glutamic acid-2-octyldodecyl ester, N-lauroyl-L-glutamic acid di(phytostearyl 2-octyldodecyl)ester, etc.; fatty acids such as isotearic acid and oleic acid;Examples of suitable oils include higher alcohols such as oleyl alcohol, isostearyl alcohol, octyldodecanol, and decyltetradecanol; lanolin derivatives such as lanolin acetate, lanolin fatty acid isopropyl, and lanolin alcohol; silicone oils such as low-polymerization dimethylpolysiloxane, high-polymerization dimethylpolysiloxane, methylphenylpolysiloxane (diphenyldimethicone), decamethylcyclopentasiloxane, octamethylcyclotetrasiloxane, and fluorine-modified organopolysiloxane; fluorine-based oils such as perfluorodecane, perfluorooctane, and perfluoropolyether; and hydrocarbon oils such as isododecane, isohexadecane, light liquid isoparaffin, liquid paraffin, heavy liquid isoparaffin, α-olefin oligomer, squalane, polyisobutylene, and polybutene. One or more of these oils can be appropriately selected and used.

[0035] The content of the liquid oil in the gel sheet is preferably 0.1 to 30% by mass, and more preferably 1 to 25% by mass, since this allows a gel sheet with good flexibility and film strength to be obtained.

[0036] Furthermore, it is more preferable that the liquid oil contains a low-viscosity liquid oil having a viscosity of 500 mPa·s or less at 20°C, and even more preferable that it contains a low-viscosity liquid oil having a viscosity of 200 mPa·s or less. The amount of such low-viscosity liquid oil in the liquid oil is preferably 30 to 100% by mass. When an oil-soluble active ingredient is blended with such a low-viscosity liquid oil, it can play a role in promoting penetration into the skin.

[0037] Examples of low-viscosity liquid oils having a viscosity of 500 mPa·s or less at 20°C include liquid paraffin, glyceryl tri-2-ethylhexanoate, pentaerythrityl tetra-2-ethylhexanoate, dimethylpolysiloxane, cetyl 2-ethylhexanoate, isotridecyl isononanoate, isopropyl myristate, octyldodecanol, decyltetradecanol, isononyl isononanoate, ethyl linoleate, cetyl lactate, methylphenylpolysiloxane (diphenyl dimethicone), etc. One or more of these can be appropriately selected and used.

[0038] The viscosity of a liquid oil is determined by the following method. Measurements are made using a Brookfield-type viscometer, a single-cylinder rotational viscometer called Vismetron (registered trademark) (manufactured by Shibaura Systems Co., Ltd.). The measurement is made by filling a glass bottle with an outer diameter of 45 mm, an inner diameter of 38 mm, and a height of 82 mm with the measurement sample, ensuring that no air spaces are formed, then capping the bottle and leaving it overnight in a thermostatic bath at 20°C. The next day, in a room adjusted to 20°C, the single-cylinder rotational viscometer called Vismetron (registered trademark) is used to measure the viscosity at 6 to 30 revolutions using the attached rotors No. 1 to No. 4, reading the measurement value after 1 minute, and multiplying the reading by the corresponding multiplier to obtain the viscosity value.

[0039] The blending amount of component (B) in the gel sheet is 0.1 to 40% by mass. If the oil content is less than 0.1% by mass, the gel will shrink significantly when dried and the moisturizing effect will not be maintained. In consideration of the gel structure and the durability of the moisturizing effect, the blending amount of component (B) is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 5% by mass or more, and particularly preferably 10% by mass or more. In addition, in consideration of the formation of the gel structure and the ease with which the gel structure collapses, the blending amount of component (B) is 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less.

[0040] (Component (C): Polyhydric alcohol) The polyhydric alcohol is the main solvent used to form the gel sheet for skin application, and is capable of imparting a high moisturizing effect to the skin.

[0041] The polyhydric alcohol is an alcohol having a structure with two or more hydroxyl groups in the skeleton. Component (C) preferably has a skeleton with 3 to 9 carbon atoms. Component (C) also preferably has a structure with 1 to 3 alkyl groups or alkylene glycol moieties in the skeleton, and more preferably the alkyl group or alkylene moiety has 3 to 6 carbon atoms. Component (C) also preferably has a structure with 2 or 3 or more hydroxy groups in the skeleton, and more preferably has 2 to 4 hydroxy groups.

[0042] The polyhydric alcohol is not particularly limited, but examples thereof include 1,3-butylene glycol, dipropylene glycol, tripropylene glycol, glycerin, diglycerin, propylene glycol, 1,2-pentanediol, etc. The polyhydric alcohols may be used alone or in combination of two or more.

[0043] From the viewpoint of compatibility with the skin, it is preferable that component (C) contains glycerin, and it is more preferable to use a combination of glycerin and 1,3-butylene glycol. When using a combination of glycerin and 1,3-butylene glycol, the mass ratio of the two (glycerin / 1,3-butylene glycol) is preferably 0.5 to 30, more preferably 1 to 20.

[0044] The content of the polyhydric alcohol in the gel sheet is 40 to 90% by mass. If the content of the polyhydric alcohol exceeds 90% by mass, the continuity of the film is significantly reduced, making it difficult to peel the gel sheet from the release substrate film (see Comparative Example 5 described below). If the content of the polyhydric alcohol in the gel sheet is less than 40% by mass, component (A) cannot be plasticized, the gel structure is less likely to collapse, and the formulation is less likely to blend with the skin (see Comparative Example 6 described below). For the same reasons, the content of the polyhydric alcohol in the gel sheet is preferably 45% by mass or more, more preferably 50% by mass or more. For the same reasons, the content of the polyhydric alcohol in the gel sheet is preferably 85% by mass or less, more preferably 80% by mass or less.

[0045] The content of the trihydric alcohol in the gel sheet is not particularly limited, but is preferably 25 to 90% by mass, and more preferably 30 to 80% by mass.

[0046] The content of the dihydric alcohol in the gel sheet is not particularly limited, but is preferably 1 to 40% by mass, and more preferably 3 to 35% by mass.

[0047] Furthermore, the mass ratio of component (C) to component (A) ((C) / (A)) is preferably 3 or more, and more preferably 5 or more. When the mass ratio of the two is at or above the lower limit, the plasticizing effect of component (C) is fully exerted, and the gel structure is easily broken down by rubbing, improving skin compatibility. This is also more preferable from the viewpoint of maintaining the moisturizing effect. The upper limit of the mass ratio of component (C) to component (A) ((C) / (A)) is, for example, 200 or less, and preferably 180 or less, taking into consideration the hardness of the film (the smooth spreading of the preparation when spread on the skin).

[0048] (Component (D): water) The water is not particularly limited, but examples thereof include purified water, distilled water, ion-exchanged water, tap water, hot spring water, and deep sea water.

[0049] The content of component (D) in the gel sheet is 10% by mass or less (lower limit: 0% by mass). If the content of component (D) in the gel sheet exceeds 10% by mass, the formability of the sheet decreases, making it difficult to peel from the release substrate. The content of component (D) in the gel sheet for skin application is preferably 8% by mass or less, and more preferably 6% by mass or less. The lower limit of the content of component (D) in the gel sheet is 0% by mass, but from the viewpoint of compatibility with the skin, it may be more than 0% by mass, or may be 0.1% by mass or more.

[0050] The content of component (D) can be adjusted to 10 to 0 mass % by drying or the like when forming a gel sheet from the O / W emulsion composition of the present technology.

[0051] The amount of component (D) can be adjusted by forming the prepared O / W emulsion composition into a sheet of the desired thickness and shape, and then drying and removing the water by a known drying method such as hot air drying, infrared drying, vacuum drying, suction drying, steam drying, hot plate drying, or freeze drying.

[0052] <Water content measurement method: Karl Fischer method> The water content in the gel sheet for skin application of the present invention can be measured using the Karl Fischer method described in JIS K 0068: 2001. In the present invention, a Karl Fischer volumetric moisture meter (such as Hiranuma Sangyo Co., Ltd.'s trace moisture analyzer (AQV-7)) can be used as a moisture meter using the Karl Fischer method, and methanol is used as the solvent.

[0053] (Component (E): at least one selected from polyvinyl alcohol and polyvinylpyrrolidone) Furthermore, it is preferable that the component (E) contains at least one selected from polyvinyl alcohol and polyvinylpyrrolidone. By further containing component (E), in combination with component (A), the gel structure is more easily broken down when force is applied, making it easier for the preparation to be more smoothly applied to the skin. More preferably, component (E) is polyvinyl alcohol. Component (E) may be used alone or in combination of two or more.

[0054] Polyvinyl alcohol is known as a raw material for cosmetics, pharmaceuticals, etc., and is widely used as an aqueous film-forming agent. Polyvinyl alcohol is produced by saponifying the acetyl groups of vinyl acetate, and is broadly divided into fully saponified types, in which saponification is almost complete, and partially saponified types, in which some acetyl groups remain. Polyvinyl alcohols are generally classified into fully saponified types (more than 98 mol%), intermediately saponified types (more than 90 mol% but not more than 98 mol%), and partially saponified types (70 mol% or more but not more than 90 mol%). Furthermore, in the present invention, polyvinyl alcohols with different degrees of saponification can be used in appropriate combination. Furthermore, the polyvinyl alcohol used in the present invention is preferably a water-soluble polyvinyl alcohol that can be dissolved in water at about 10 to 30°C. In the present invention, any saponification type can be used, but the lower limit of the saponification degree is preferably 70 mol% or more, more preferably 75 mol% or more, even more preferably 80 mol% or more, and even more preferably 85 mol% or more, and the upper limit of the saponification degree is preferably 98 mol% or less, more preferably 97 mol% or less, even more preferably 95 mol% or less, and even more preferably 90 mol% or less, and the numerical range is more preferably 70 to 90 mol%, even more preferably 80 to 90 mol%, and even more preferably 85 to 90 mol%. By setting the range, a gel sheet with good flexibility and film strength can be obtained.

[0055] <Method for measuring saponification degree> The degree of saponification is the proportion of acetate groups (acetoxy groups: -OCOCH3) contained in polyvinyl acetate resin, the raw material for polyvinyl alcohol resin, that are converted to hydroxyl groups during the saponification process, expressed as a unit ratio (mol %), and is defined by the following formula: Saponification degree (mol %) = 100 × (number of hydroxyl groups) ÷ (number of hydroxyl groups + number of acetate groups). The degree of saponification can be determined in accordance with JIS K 6726:1994.

[0056] The degree of polymerization of polyvinyl alcohol is not particularly limited, and commercially available products can be used. The degree of polymerization is preferably 100 to 4000, more preferably 100 to 2000, even more preferably 100 to 1000, and even more preferably 200 to 700.

[0057] The polyvinyl alcohol may be one in which both the saponification degree and polymerization degree described above have been adjusted, and is preferably partially saponified and has a polymerization degree of 100 to 4000, more preferably has a saponification degree of 80 to 90 mol% and a polymerization degree of 100 to 1000, and even more preferably has a saponification degree of 80 to 90 mol% and a polymerization degree of 200 to 700. The polymerization degree of polyvinyl alcohol can be measured by a solution viscosity measurement method in accordance with JIS K6726:1994 (Testing method for polyvinyl alcohol).

[0058] Commercially available polyvinyl alcohol products include, for example, Kuraray Poval 5-88, Kuraray Poval 22-88, Kuraray Poval 30-88, and Kuraray Poval 44-88 (all of which have a saponification degree of 88 mol%, manufactured by Kuraray Co., Ltd.), Gohsenol EG-05, and Gohsenol EG-40 (all of which have a saponification degree of 88 mol%, manufactured by Nippon Synthetic Co., Ltd.).

[0059] In the present invention, preferably, an embodiment in which polyvinyl alcohol and an acrylic acid-based polymer are used in combination is excluded.

[0060] Polyvinylpyrrolidone is a polymer compound obtained by polymerizing N-vinyl-2-pyrrolidone. Natural, semi-synthetic, or synthetic polyvinylpyrrolidone can be used. In the present invention, from the viewpoint of gel structure disintegration, the weight-average molecular weight of polyvinylpyrrolidone is preferably 900,000 to 2,000,000, and more preferably 1,000,000 to 1,800,000. These molecular weights refer to weight-average molecular weights measured by the SEC method.

[0061] Commercially available polyvinylpyrrolidone products include, for example, Rubiscol K12, Rubiscol K17, Rubiscol K30, Rubiscol L60, Rubiscol K80, and Rubiscol K90 (manufactured by BASF); and PVP K15, PVP K17, PVP K30, PVP K60, PVP K90, and PVP K120 (all manufactured by Ashland).

[0062] The content of component (E) in the gel sheet is preferably less than 5% by mass. By using a small amount of component (E) in combination with component (A), the gel structure is more easily broken down, making it easier to apply to the skin. In consideration of the effects of the present invention, the content of component (E) in the gel sheet is preferably 0.1% by mass or more and less than 5% by mass, and more preferably 0.5% by mass or more and less than 5% by mass.

[0063] Considering the ease with which the gel structure collapses, the content mass ratio of component (E) to component (A) ((E) / (A)) is preferably 0.01 to 15, more preferably 0.05 to 10, and even more preferably 0.1 to 3.

[0064] (Ingredient (F): Active ingredient) Since the gel sheet of the present embodiment can be applied entirely to the skin, the active ingredient is efficiently absorbed into the skin. Therefore, the gel sheet of the present invention preferably contains an active ingredient.

[0065] Ingredients (F) include antibacterial agents such as benzoic acid, sodium benzoate, parahydroxybenzoic acid esters, benzalkonium chloride, phenoxyethanol, and isopropylmethylphenol; arbutin, ellagic acid, linoleic acid, vitamin C (ascorbic acid) and its derivatives (such as L-ascorbic acid 2-glucoside), vitamin E and its derivatives, glycyrrhizic acid and its derivatives (such as dipotassium glycyrrhizinate), glycyrrhetinic acid and its derivatives, tranexamic acid, placenta extract, chamomile extract, licorice extract, pearl berry extract, and Scutellaria root extract. Whitening agents such as seaweed extract, Sophora root extract, Kaempferia extract, Gokahi extract, rice bran extract, wheat germ extract, Chinese radish extract, Hawthorn extract, Sunflower extract, White lily extract, Peony extract, Siberian laurel extract, Solanum sieboldii extract, soybean extract, tea extract, molasses extract, White angelica tree extract, grape extract, hop extract, Myrtle extract, Mokka extract, and Saxifraga extract; retinoids such as retinol, retinoic acid, retinol acetate, and retinol palmitate; B vitamins such as nicotinic acid and its derivatives (nicotinamide, etc.); citric acid; Anti-wrinkle agents such as fruit acids, alpha-hydroxy acids such as glycolic acid and lactic acid, alpha-hydroxy acid cholesterol, rutin sugar derivatives, N-methylserine, elastin, collagen, sericin, Centella asiatica extract, and gold extract; sulfur and its derivatives, glycyrrhizic acid and its derivatives, glycyrrhetinic acid and its derivatives, althea extract, angelica extract, arnica extract, intang extract, nettle extract, Phellodendron bark extract, St. John's wort extract, chamomile extract, goldfish extract, watercress extract, comfrey extract, salvia extract, and lithospermum root extract anti-inflammatory agents such as perilla extract, birch extract, and gentian extract; caffeine, cockscomb extract, seashell extract, royal jelly, silk protein and its degradation products or derivatives thereof, lactoferrin or its degradation products, chondroitin sulfate, mucopolysaccharides such as hyaluronic acid or salts thereof, collagen, yeast extract, lactic acid bacteria extract, bifidobacterium extract, fermentation metabolism extract, ginkgo extract, barley extract, Swertia japonica extract, Chinese ginseng extract, carrot extract, rosemary extract, glycolic acid, citric acid, lactic acid, malic acid, tartaric acid, and succinic acid;Superoxide dismutase, mannitol, quercetin, catechin and its derivatives, rutin and its derivatives, Moutan tree extract, Alpinia oleracea extract, Melissa extract, Monk fruit extract, retinol and its derivatives, vitamin A such as carotenoids, thiamine and its derivatives, riboflavin and its derivatives, pyridoxine and its derivatives, vitamin B such as nicotinic acid and its derivatives, vitamin E such as tocopherol and its derivatives, active oxygen scavengers such as dibutylhydroxytoluene and butylhydroxyanisole; proteins such as elastin, keratin, etc. These include derivatives, hydrolyzates and salts thereof, amino acids and derivatives thereof such as glycine, serine, ascorbic acid, glutamic acid, arginine, and theanine, sugars such as trehalose, inositol, glucose, sucrose and derivatives thereof, dextrin and derivatives thereof, honey, and other sugars, D-panthenol and derivatives thereof, urea, phospholipids, ceramides, moisturizers such as coptis jasmine extract, calamus extract, rehmannia root extract, cnidium extract, mallow extract, thyme extract, houttuynia cordata extract, hamamelis extract, linden extract, horse chestnut extract, and quince extract;

[0066] The gel sheet of the present invention is characterized by its low water content, and when applied to moist skin, it is expected that the water-soluble ingredients will be efficiently transferred to the skin. Therefore, component (F) is preferably a water-soluble ingredient, as this is expected to further enhance the effects of the present invention, and more preferably at least one selected from the group consisting of nicotinamide, dipotassium glycyrrhizinate, vitamin C (ascorbic acid) and its derivatives, and tranexamic acid.

[0067] The content of component (F) is preferably 0.01 to 10% by mass, more preferably 0.05 to 7% by mass, taking into consideration the effect of the active ingredient or saturation of the effect.

[0068] (Component (G): Surfactant) In the present invention, it is preferable to produce an emulsion composition as described below, and from the viewpoint of easily producing a good emulsion composition, it is preferable to further use a surfactant as component (G).

[0069] The surfactant is not particularly limited, and examples thereof include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants (lipophilic and hydrophilic), and one or more surfactants may be appropriately selected and used. Furthermore, one or more surfactants selected from the following examples may be used.

[0070] Examples of anionic surfactants include fatty acid soaps (e.g., sodium laurate, sodium palmitate, etc.); higher alkyl sulfates (e.g., sodium lauryl sulfate, potassium lauryl sulfate, etc.); alkyl ether sulfates (e.g., POE-lauryl triethanolamine sulfate, POE-lauryl sodium sulfate, etc.); N-acyl sarcosinates (e.g., sodium lauroyl sarcosinate, etc.); higher fatty acid amide sulfonates (e.g., sodium N-myristoyl-N-methyl taurate, sodium coconut oil fatty acid methyl taurate, sodium stearoyl methyl taurate, sodium lauryl methyl taurate, etc.); sulfosuccinates (e.g., sodium di-2-ethylhexyl sulfosuccinate, sodium monolauroyl monoethanolamide polyoxyethylene sulfosuccinate, sodium lauryl polypropylene glycol sulfosuccinate, etc.); alkyl Examples of suitable benzenesulfonates include: benzenesulfonates (e.g., sodium linear dodecylbenzenesulfonate, triethanolamine linear dodecylbenzenesulfonate, and linear dodecylbenzenesulfonic acid); higher fatty acid ester sulfates (e.g., sodium hydrogenated coconut oil fatty acid glycerin sulfate); N-acylglutamates (e.g., monosodium N-lauroylglutamate, disodium N-stearoylglutamate, monosodium N-myristoyl-L-glutamate); sulfated oils (e.g., turmeric oil); POE-alkyl ether carboxylic acids; POE-alkyl allyl ether carboxylates; α-olefin sulfonates; higher fatty acid ester sulfonates; secondary alcohol sulfates; higher fatty acid alkylolamide sulfates; sodium lauroylmonoethanolamide succinate; N-palmitoyl aspartic acid ditriethanolamine; and sodium caseinate.

[0071] Examples of cationic surfactants include alkyltrimethylammonium salts (e.g., stearyltrimethylammonium chloride, lauryltrimethylammonium chloride, etc.); alkylpyridinium salts (e.g., cetylpyridinium chloride, etc.); dialkyldimethylammonium chloride salts (e.g., distearyldimethylammonium chloride, etc.); poly(N,N'-dimethyl-3,5-methylenepiperidinium chloride); alkyl quaternary ammonium salts; alkyldimethylbenzylammonium salts; alkylisoquinolinium salts; dialkylmorphonium salts; POE-alkylamines; alkylamine salts; polyamine fatty acid derivatives; amyl alcohol fatty acid derivatives; benzalkonium chloride; benzethonium chloride, etc.

[0072] Examples of amphoteric surfactants include imidazoline-based amphoteric surfactants (e.g., 2-undecyl-N,N,N-(hydroxyethylcarboxymethyl)-2-imidazoline sodium, 2-cocoyl-2-imidazolinium hydroxide-1-carboxyethyloxy disodium salt, etc.); betaine-based surfactants (e.g., 2-heptadecyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, lauryldimethylaminoacetic acid betaine, alkyl betaine, amido betaine, sulfobetaine, etc.); and phospholipids (e.g., lecithin, hydrogenated lecithin, etc.). Lecithin can be derived from soybeans, eggs, etc.

[0073] Examples of lipophilic nonionic surfactants include sorbitan fatty acid esters (e.g., sorbitan monooleate, sorbitan monoisostearate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan sesquioleate, sorbitan trioleate, diglycerol sorbitan penta-2-ethylhexylate, diglycerol sorbitan tetra-2-ethylhexylate, etc.); polyglycerin fatty acid esters (e.g., polyglyceryl-2 triisostearate, polyglyceryl-2 diisostearate, polyglyceryl-3 diisostearate); propylene glycol fatty acid esters (e.g., propylene glycol monostearate, etc.); hydrogenated castor oil derivatives; glycerin alkyl ethers, etc.

[0074] Examples of hydrophilic nonionic surfactants include POE-sorbitan fatty acid esters (e.g., POE-sorbitan monooleate, POE-sorbitan monostearate, POE-sorbitan tetraoleate, etc.); POE sorbit fatty acid esters (e.g., POE-sorbitan monolaurate, POE-sorbitan monooleate, POE-sorbitan pentaoleate, POE-sorbit monostearate, etc.); POE-glycerin fatty acid esters (e.g., POE-glycerin monostearate, POE-glycerin monoisostearyl ester); POE-monooleates such as POE-glycerin triisostearate, etc.; POE-fatty acid esters (e.g., POE-distearate, POE-monodioleate, ethylene glycol distearate, etc.); POE-alkyl ethers (e.g., POE-lauryl ether, POE-oleyl ether, POE-stearyl ether, POE-behenyl ether, POE-2-octyldodecyl ether, POE-cholestanol ether, POE-phytosterol ether, etc.); Pluronic types (e.g., Pluronic (registered trademark) registered trademarks), etc.); POE·POP-alkyl ethers (e.g., POE·POP-cetyl ether, POE·POP-2-decyltetradecyl ether, POE·POP-monobutyl ether, POE·POP-hydrogenated lanolin, POE·POP-glycerin ether, etc.); tetraPOE·tetraPOP-ethylenediamine condensates (e.g., Tetronic, etc.); POE-castor oil hydrogenated castor oil derivatives (e.g., POE-castor oil, POE-hydrogenated castor oil, POE-hydrogenated castor oil monoisostearate, POE-hydrogenated castor oil triisostearate, POE-hydrogenated castor oil monopyroglutamic acid monoisostearate diester, POE-hydrogenated castor oil maleic acid, etc.); POE-beeswax and lanolin derivatives (e.g., POE-sorbitol beeswax, etc.); alkanolamides (e.g., coconut oil fatty acid diethanolamide, lauric acid monoethanolamide, fatty acid isopropanolamide, etc.); POE-propylene glycol fatty acid esters; POE-alkylamines; POE-fatty acid amides; sucrose fatty acid esters; alkylethoxydimethylamine oxide; trioleyl phosphate, etc.

[0075] Among these, it is preferable to use at least a phospholipid (preferably, lecithin, hydrogenated lecithin, etc.) as the surfactant. In this case, a combination of a phospholipid with another surfactant is also a suitable embodiment, and a combination of a higher fatty acid amide sulfonate (preferably, sodium stearoyl methyl taurate, etc.) and a phospholipid is more preferred; or a combination of a POE-alkyl ether (preferably, POE-phytosterol ether, etc.) and a phospholipid is more preferred.

[0076] Furthermore, the content of the surfactant in the gel sheet for skin application in the present invention is not particularly limited, but is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, and is preferably 3% by mass or less, more preferably 2.5% by mass or less, even more preferably 2% by mass or less.

[0077] (optional ingredient) The gel sheet for application to skin of the present invention may contain, as needed, any optional components contained in ordinary topical skin preparations, such as water-soluble polymers other than components (A) and (E), powder components, ultraviolet absorbers, sequestering agents, lower alcohols, neutralizing agents, organic amines, pH adjusters, antioxidants, antioxidant aids, preservatives, fragrances, etc., within the scope of not interfering with the effects of the present invention.

[0078] Examples of water-soluble polymers other than components (A) and (E) include natural water-soluble polymers such as gum arabic, tragacanth gum, galactan, guar gum, carob gum, karaya gum, pectin, quince seed, algae colloid (cassow extract), starch (rice, corn, potato, wheat), xanthan gum, dextran, succinoglucan, pullulan, etc.), collagen, casein, albumin, gelatin, etc.; examples of semi-synthetic water-soluble polymers include starch-based polymers such as carboxymethyl starch and methylhydroxypropyl starch; methylcellulose, ethylcellulose, etc. cellulose-based polymers such as cellulose, methylhydroxypropyl cellulose, hydroxyethyl cellulose, sodium cellulose sulfate, hydroxypropyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, and crystalline cellulose; semi-synthetic water-soluble polymers such as alginic acid-based polymers other than component (A) such as propylene glycol alginate; vinyl-based polymers such as polyvinyl methyl ether; polyoxyethylene-based polymers such as polyethylene glycol 20,000, 40,000, and 60,000 polyoxyethylene-polyoxypropylene copolymers; polyethyleneimine;Carboxyvinyl polymers, alkyl-modified carboxyvinyl polymers, crosslinked copolymers of acrylamide and 2-acrylamido-2-methylpropanesulfonic acid, crosslinked copolymers of acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid, copolymers of acrylic acid and alkyl acrylate esters, copolymers of acrylic acid, alkyl acrylate esters, and alkyl methacrylate esters, copolymers of acrylic acid, alkyl acrylate esters, and polyethylene glycol acrylate esters, copolymers of acrylic acid, alkyl methacrylate esters, and polyoxyethylene monoalkyl ether acrylate esters Examples of suitable water-soluble polymers include copolymers of acrylic acid, acrylic acid alkyl esters, and methacrylic acid (polyoxyethylene monoalkyl ether) esters, copolymers of itaconic acid, acrylic acid alkyl esters, and methacrylic acid (polyoxyethylene monoalkyl ether) esters, copolymers of acrylic acid, acrylic acid alkyl esters, and itaconic ... and synthetic water-soluble polymers such as acrylic acid-based polymers such as hydroxyethyl acrylate and sodium acryloyldimethyltaurate copolymers, sodium acrylate and acryloyldimethyltaurate copolymers, and acrylamide and sodium acryloyldimethyltaurate copolymers;

[0079] Next, the raw material composition of the gel sheet for skin application and the method for producing the gel sheet for skin application of the present invention will be described.

[0080] The gel sheet for application to skin of the present invention can be obtained by (i) preparing an O / W emulsion composition containing components (A) to (D) and, if necessary, components (E) to (G) and any optional components, and (ii) forming the O / W emulsion composition into a sheet and drying it to a predetermined water content. Note that, in one embodiment, the water content is reduced by drying when obtaining the gel sheet, so the content of water (=component (D)) in the O / W emulsion composition does not necessarily coincide with the content of component (D) in the gel sheet.

[0081] The method for emulsifying the composition in (i) above may be a known emulsification method.

[0082] The O / W emulsion composition used in the present invention can be obtained by emulsifying components (A) to (D), and optionally components (E) to (G), and optional components, by mixing, etc. More specifically, the O / W emulsion composition can be obtained by emulsifying an oil phase containing at least component (B) an oil solution, and an aqueous phase containing at least component (A), component (C) a polyhydric alcohol, and component (D) water.

[0083] In one example of a method for producing an O / W emulsion composition, component (A) is dissolved in an aqueous system containing component (C) a polyhydric alcohol and component (D) water, and then component (B) an oil is dispersed in this aqueous system. In this production process, components (E) to (G) and optional components may be added as needed to improve dispersibility or to add components that are expected to have certain effects.

[0084] In one example of a method for producing an O / W emulsion composition, an oil phase containing component (B) an oil solution and component (C) a polyhydric alcohol is added to an aqueous phase containing component (D) water in which component (A) has been dissolved, followed by emulsification. In this production process, components (E) to (G) and optional components may be added as needed to improve dispersibility or to add components that are expected to have certain effects.

[0085] In one example of a method for producing an O / W emulsion composition, a dispersion containing component (D) water and component (G) surfactant is mixed and dispersed with component (B) oil, and then an aqueous system containing component (A), component (C) polyhydric alcohol, and water is dispersed in this dispersion. In this production process, components (E) to (G) and optional components may be added as needed to improve dispersibility or to add components that are expected to have certain effects.

[0086] The amount of water used in the O / W emulsion composition can be adjusted so that it is an amount that can form an O / W emulsion and a gel sheet with a desired moisture content after drying. The amount of water is not particularly limited, but it is preferable to adjust it so that it is 10 to 50% by mass in the O / W emulsion composition.

[0087] The skin patch sheet can be obtained by forming the O / W emulsion composition into a sheet of the desired thickness and shape, and then drying and removing the water content to the desired level using a known drying method (e.g., hot air drying, infrared drying, vacuum drying, suction drying, steam drying, hot plate drying, freeze drying, etc.).

[0088] Methods for forming the skin-adhesive gel sheet of the present invention include, for example, a method in which a composition for forming a gel sheet is spread to a uniform thickness on a release substrate film, heated and dried, and then cut to obtain a sheet of a desired shape (casting method); a method in which the composition is coated to a desired thickness on a release substrate film using a roll, blade, calendar, etc., heated and dried, and then cut to obtain a sheet of a desired shape (coating method); a method in which the composition is filled into a frame (tray) formed of a resin or the like, and then heated and dried to obtain a sheet of a desired shape; and a method in which a stencil having openings corresponding to the shape of the gel sheet is used, the openings are filled with the composition, the composition is printed on a release substrate film, and then heated and dried to obtain a sheet of a desired shape (stencil printing), etc., but any of these methods can be used. The skin-adhesive gel sheet of the present invention may be stored or sealed in a packaging container made of plastic or the like with the release substrate attached. The release substrate is preferably a substrate from which the skin-adhesive gel sheet of the present invention can be peeled off when used, and is not particularly limited to a film but may also be a tray, etc., and its material is also not particularly limited.

[0089] Examples of materials for the release substrate film and tray to be used include polyethylene, polyethylene terephthalate, polybutylene terephthalate, polypropylene, polystyrene, polycarbonate, polyvinyl chloride, polyvinylidene chloride, paper, etc., and various coatings such as silicone and fluorine can be applied to the surface to make the gel sheet for skin application of the present invention easier to peel off.

[0090] The gel sheet may be formed into any shape suitable for easy application to the target area, such as a circle, oval, square, magatama, or face shape.

[0091] The gel sheet for application to the skin obtained by the method for producing a gel sheet for application to the skin as described above has the effects of excellent moisturizing effect, usability (film strength, no burden on the film, solubility in water), and sheet formability. Furthermore, the obtained gel sheet for application to the skin has excellent moisturizing effect while also having flexibility and strength, so it does not require a support and is excellent in usability, and furthermore, due to its high water solubility, it can be easily dissolved in water and applied to the skin.

[0092] <How to use the skin adhesive gel sheet> The gel sheet for skin application of the present invention can be used not only by itself, but also by applying the sheet to the skin and then massaging it into the skin. This allows the sheet to easily disintegrate, allowing each active ingredient to be effectively absorbed into the skin. The gel sheet for skin application of the present invention can be formed into a sheet without a support, and the gel disintegrates smoothly without the application of force, making it easy to apply to the skin.

[0093] The gel sheet for skin application of the present invention has an outer phase composed of component (A), component (C) a polyhydric alcohol, component (D) water, and optional components, and an oily agent (B) dispersed in the outer phase. Therefore, the gel is softened by the plasticizing effect of the oily agent.

[0094] The thickness of the film of the gel sheet for skin application of the present invention can be set as appropriate, but is, for example, 50 to 2000 μm, preferably 100 to 1000 μm.

[0095] The thickness of the gel sheet film in the present invention is a value measured using a digital micrometer (MDE-25MJ, manufactured by Mitutoyo Corporation) after the gel has dried. [Example]

[0096] The effects of the present invention will be explained using the following examples and comparative examples. In the examples, the units "parts" and "%" are sometimes used, but unless otherwise specified, they represent "parts by mass" or "% by mass." Unless otherwise specified, each operation is carried out at room temperature (25°C).

[0097] <Examples 1 to 16 and Comparative Examples 1 to 6: Gel Sheets for Skin Adhesion> Gel sheets for application to the skin having the compositions shown in Table 1 were prepared by the manufacturing method described below, and the items of "transferability to the skin," "hardness of the coating film," "compatibility with the skin," and "sustained moisturizing effect" were evaluated using the evaluation methods and criteria described below, and the results are also shown in Table 1. (Manufacturing method) (1): Heat ingredients (11) to (16) to 90°C and mix until uniformly dissolved. (2): Heat ingredients (7) to (10), (18), and (19) to 70°C, mix and dissolve uniformly, and then mix with (1). (3): Add 30% purified water (not included in the formula) to ingredients (2) to (6), (17), (20), and (21), heat to 70°C, and mix until uniformly dissolved. (4) At 70°C, the mixture obtained in (2) is added to the mixture obtained in (3) while stirring, emulsified, and then cooled to room temperature. (5): 5% purified water not included in the formulation is added to component (1) and dissolved, and then added to (4) and mixed to obtain an O / W emulsion composition. (6): The composition obtained in (5) was spread onto a polyethylene terephthalate film using a doctor blade to form a uniform thickness, and then heated and dried in a 60°C air dryer for 1 hour to reduce the water content to 10% or less. The composition was then cooled at room temperature to obtain a 200 μm thick gel sheet for application to the skin.

[0098] The proportion of water added during the production process is the proportion when the components (1) to (22) constituting the gel sheet are taken as 100%. The same applies to the other examples below.

[0099] (Evaluation method 1: Transferability to skin (gel sheet strength)) Ten expert evaluators evaluated the strength of each sheet when peeling it from the polyethylene terephthalate film, which was the release base film, according to the following three-level evaluation criteria, and the average score was calculated and evaluated according to the following criteria. Note that the term "single film" used in the evaluation criteria means that the sheet exists as a single film without being torn. (Rating): 3 points: The gel sheet is completely crack-free and transfers neatly as a single layer. 2 points: The gel sheet cracks, but it is transferred as a single film and can be used without any problems. 1 point: The gel sheet adheres to the release base film and is very difficult to peel off, not forming a single film. (judgement): ◎(Excellent): 2.5 points or more, 〇 (Good): 2 points or more and less than 2.5 points, × (poor): Less than 2 points.

[0100] (Evaluation Method 2: Storage Modulus of Gel Sheet) The storage modulus G' was measured using a stress-controlled rheometer at 35°C, a frequency of 50 Hz, and a strain of 1%, and the samples were classified according to the following evaluation criteria. The storage modulus G' was measured using a dynamic viscoelasticity measuring device, Discovery HR20 (manufactured by TA Instruments). (judgement) ◎: G'≦10000 Pa, ○:10000Pa <G’≦20000Pa、 △:20000Pa <G’≦40000Pa、 ×: G'>40000 Pa.

[0101] (Evaluation method 3: Skin compatibility) Each gel sheet was cut into a square measuring 2 cm on each side and applied to the inside of the forearm. Five minutes after application, the sheet was massaged with the fingers to break down the gel sheet's membrane structure. Ten expert evaluators evaluated the ease with which the sheet blended into the skin according to the following four-point scale.

[0102] (Rating): (Evaluation) 4 points: The film structure breaks down easily when massaged, allowing it to be smoothly absorbed into the skin. 3 points: You need to apply a little pressure, but massaging it in breaks down the membrane structure and allows it to blend in. 2 points: When massaged, the film structure breaks down, but the film breaks down and becomes like crumbly residue, making it difficult to blend into the skin. 1 point: The membrane structure does not collapse even when massaged. (Judgment): (Average score) ◎(Excellent): 3.5 points or more, 〇 (Good): 2.5 points or more and less than 3.5 points, △ (slightly poor): 1.5 points or more and less than 2.5 points, × (Poor): Less than 1.5 points.

[0103] (Evaluation method 4: Durability of moisturizing effect) The initial moisture content of uncoated skin on the inside of the forearm was measured using a SKICON-200EX (manufactured by IBS). Each gel sheet was cut into a 2cm square and applied to the inside of the forearm. 30 minutes after application, the sheet was rubbed into the skin, and the moisture content was measured 6 hours after application. Each sample was measured on five healthy volunteers. The initial moisture content was set at 100, and the moisture content 6 hours after application was calculated as a relative value. The moisturizing effect was evaluated according to the average relative moisture content of each panel according to the following 4-point scale. (Judgment): (Average moisture content relative to the initial moisture content) ◎150% or more, ○ Less than 150% 130% or more △ Less than 130% 110% or more ×Less than 110%.

[0104] [Table 1-1]

[0105] [Table 1-2]

[0106] [Table 1-3]

[0107] *1: Snow Algin M (manufactured by Fuji Chemical Industry Co., Ltd.) *2: Carrageenan J (manufactured by Kyokuto Chemical Industry Co., Ltd.) *3: SeaPure Agarose (manufactured by Lonza) *4:Metolose 65SH-4000 (Shin-Etsu Chemical Co., Ltd.) *5: Pineflow S (Matsutani Chemical Industry Co., Ltd.) *6: WHITE BEES WAX (Miki Chemical Co., Ltd.) *7: PERFORMALENE 500 (manufactured by New Phase Technologies) *8: Cetostearyl alcohol (Kyushu Alcohol Kogyo Co., Ltd.) *9: PLANDOOL-S (manufactured by Nippon Fine Chemicals) *10: CARNAION (manufactured by SONNEBORN, LLC) *11: Kuraray Poval 5-88 (saponification degree 88 mol%, polymerization degree 500, manufactured by Kuraray Co., Ltd.) *12: Resinol S-10 (Nikko Chemicals) *13: Nikkor SMT (manufactured by Nikko Chemicals) *14: CARBOPOL 980 (manufactured by Lubrizol Advanced Materials).

[0108] As can be seen from the above table, the gel sheets for skin application in Examples 1 to 16 were excellent in all of the following: "transferability to skin," "compatibility with skin," and "sustained moisturizing effect." The storage modulus was also 20,000 Pa or less. On the other hand, in Comparative Example 1, where component (A) was not present, the film structure was difficult to break down even when massaged with the hands. In Comparative Example 2, where the amount of component (A) exceeded the upper limit, both compatibility with skin and sustained moisturizing effect were poor, and the storage modulus was also high. In Comparative Examples 3 and 4, where component (A) was replaced with other polysaccharides, the film strength was low and transferability to skin was significantly poor. In Comparative Example 5, where the amount of polyhydric alcohol exceeded 90% by mass, it was difficult to transfer the gel sheet to the skin. Conversely, in Comparative Example 6, where the amount of polyhydric alcohol was less than 40% by mass, both compatibility with skin and sustained moisturizing effect were poor, and the storage modulus was also high. In addition, the aqueous gel sheet of Comparative Example 7 lacked film continuity, making it difficult to transfer the gel sheet to the skin, and also lacked moisturizing properties. Compared to Example 1 and Example 13, Example 13 blended better with the skin and turned into a smoother cream when released.

[0109] Example 17: Gel sheet for skin application (components) (mass%) 1. Dipotassium glycyrrhizinate (ingredient (F)) 0.1 2. Fucoidan (ingredient (A)) *15 0.5 3. Glycerin (ingredient (C)) 55.0 4. 1,3-Butylene glycol (component (C)) 10.0 5. Tripropylene glycol (ingredient (C)) 5.0 6. 1,2-Pentanediol (Component (C)) 0.5 7. Synthetic wax (melting point 80-88°C) (ingredient (B): solid oil) *A 3.0 8. Cetostearyl alcohol (melting point 50-63°C) (ingredient (B): solid oil) *8 3.0 9. Paraffin (melting point 56-61°C) (Component (B): solid oil) *B 1.0 10. Bis-diglyceryl polyacyladipate-2 (ingredient (B): semi-solid oil) *C 0.5 11. Polyglyceryl-2 Diisostearate *D 3.0 12. Isotridecyl isononanoate (Component (B): Liquid oil) *E 2.0 13. Decyltetradecanol (Component (B): Liquid oil) *F 2.0 14. Hydrogenated lecithin *12 (ingredient (G)) 1.0 15. Sodium Stearoyl Methyl Taurate (ingredient (G)) *13 0.3 16. Polyvinyl alcohol (ingredient (E)) *G 4.0 17. (Acrylic acid / C10-30 alkyl acrylate) copolymer *H 0.4 18. Sodium hydroxide 0.2 19.Fragrance 0.1 20. Purified water (ingredient (D)) remaining (7.4) *15: Okinawa Mozuku Fucoidan (manufactured by South Products) *A: CIREBELLE 108 (manufactured by CIREBELLE) *B: PARACERA256 (manufactured by PARAMELT) *C:SOFTISAN 649 (manufactured by SASOL GERMANY GMBH) *D: Cosmol 43V (manufactured by Nisshin Oillio Group) *E: Salakos 913 (manufactured by Nisshin Oillio Group) *F: Lisonol 24SP (Kyukyu Alcohol Kogyo Co., Ltd.) *G: Kuraray Poval 44-88 (Kuraray Co., Ltd.) *H: PEMUREN TR-1 (Manufactured by LUBRIZOL ADVANCED MATERIALS) (Manufacturing method) (1): Heat ingredients (7) to (13) to 90°C and mix until uniformly dissolved. (2): Heat ingredients (3) to (6), (14), and (15) to 70°C, mix and dissolve uniformly, and then mix with (1). (3): Add 30% water to ingredients (2) and (16) to (18), heat to 70°C, and mix until uniformly dissolved. (4) At 70°C, the mixture obtained in (2) is added to the mixture obtained in (3) while stirring, emulsified, and then cooled to room temperature. (5): Add 5% water to component (1) and dissolve, then add to (4) and mix. (6): Component (19) is added to the mixture obtained in (5) and mixed to obtain an O / W emulsion type raw material composition. (7) Using a metal mask with magatama-shaped holes, the composition obtained in (6) was stencil-printed onto a 50 μm thick polyvinyl chloride substrate, and then vacuum-dried to reduce the water content to 10% or less, to obtain a 400 μm thick gel sheet for application to the skin.

[0110] The gel sheet for skin application of Example 17 was excellent in all of "transferability to skin," "compatibility with skin," and "sustained moisturizing effect." The storage modulus was 20,000 Pa or less. The mass ratio of component (C) to component (A) ((C) / (A)) was 141.

[0111] Example 18: Gel sheet for skin application (components) (mass%) 1. Tranexamic acid ((ingredient (F)) 0.5 2. Sodium alginate ((ingredient (A)) *1 5.0 3. Glycerin (ingredient (C)) 65.0 4. 1,3-Butylene glycol (component (C)) 10.0 5. Microcrystalline wax (melting point 76-83°C) (ingredient (B): solid oil) *I 1.0 6. Cetostearyl alcohol (melting point 50-63°C) (ingredient (B): solid oil) *8 3.0 7. Di(octyldodecyl / phytosteryl / behenyl) lauroyl glutamate (ingredient (B): semi-solid oil) *J 2.0 8. Diphenyl dimethicone (ingredient (B): liquid oil) *K 2.0 9. Diisostearyl malate (ingredient (B): liquid oil) *L 2.0 10. Isononyl isononanoate (Component (B): Liquid oil) *M 2.0 11. Dimethylpolysiloxane (Component (B): Liquid oil) *N 0.2 12. Hydrogenated lecithin (ingredient (G)) *12 1.0 13. Sodium Stearoyl Methyl Taurate (ingredient (G)) *13 0.3 14. (Acrylic acid / C10-30 alkyl acrylate) copolymer *O 0.4 15. Sodium hydroxide 0.2 16.Fragrance 0.1 17. Purified water (ingredient (D)) remaining (5.3) *I: MULTIWAX W445 (SONNEBORN) *J: Eldew PS-306 (Ajinomoto Co., Inc.) *K: KF-54 (Shin-Etsu Chemical Co., Ltd.) *L: Cosmol 222 (manufactured by Nisshin Oillio Group) *M: Salakos 99 (manufactured by Nisshin Oillio Group) *N: KF-96-100CS (Shin-Etsu Chemical Co., Ltd.) *O: CARBOPOL 1382 (Manufactured by LUBRIZOL ADVANCED MATERIALS) (Manufacturing method) (1): Heat ingredients (5) to (11) to 90°C and mix until uniformly dissolved. (2): Heat ingredients (3), (4), (12), and (13) to 70°C, mix and dissolve uniformly, and then mix with (1). (3): Add 30% water to ingredients (2), (14) and (15), heat to 70°C, and mix until uniformly dissolved. (4) At 70°C, the mixture obtained in (2) is added to the mixture obtained in (3) while stirring, emulsified, and then cooled to room temperature. (5): Add 5% water to component (1) and dissolve, then add to (4) and mix. (6): Component (16) is added to the mixture obtained in (5) and mixed to obtain an O / W emulsion type raw material composition. (7) A polypropylene film was placed on the bottom of a polystyrene tray with a magatama-shaped depression, and the composition obtained in (6) was poured onto the film. The film was then heated and dried at 60°C for one hour to obtain a 400 μm-thick gel sheet for application to the skin.

[0112] The gel sheet for skin application of Example 18 was excellent in all of "transferability to skin," "compatibility with skin," and "sustained moisturizing effect." The storage modulus was 20,000 Pa or less. The mass ratio of component (C) to component (A) ((C) / (A)) was 15.

[0113] Example 19: Gel sheet for skin application (components) (mass%) 1. L-Ascorbic acid 2-glucoside (component (F)) 2.0 2. Citric acid (component (F)) 0.03 3. Sodium citrate 0.2 4. Sodium alginate (ingredient (A)) *1 5.0 5. Glycerin (ingredient (C)) 45.0 6. 1,3-Butylene glycol (ingredient (C)) 10.0 7. Dipropylene glycol (ingredient (C)) 20.0 8. Beeswax (melting point 60-67°C) (ingredient (B): solid oil) *6 3.0 9. Behenyl alcohol (melting point 65-73°C) (ingredient (B): solid oil) 2.0 10. Dimer dilinoleic acid (phytosteryl / isostearyl / cetyl / stearyl / behenyl) (ingredient (B): semi-solid oil) *9 1.0 11. (Dimethicone / vinyl dimethicone) crosspolymer (dimethicone soluble) *P 1.0 12. Isopropyl myristate (ingredient (B): liquid oil) *Q 2.0 13. Cetyl 2-ethylhexanoate (ingredient (B): liquid oil) *R 1.0 14. Dimethylpolysiloxane (Component (B): Liquid oil) *N 0.2 15. Hydrogenated lecithin (ingredient (G)) *12 1.0 16. Sodium Stearoyl Methyl Taurate (ingredient (G)) *13 0.3 17. 40% dispersion of crosslinked copolymer of acrylamide and 2-acrylamido-2-methylpropanesulfonic acid *S 0.5 18. Sodium hydroxide 0.3 19. Methylparaben 0.05 20. Purified water (ingredient (D)) remaining (5.72) *P: KSG-16 (Shin-Etsu Chemical Co., Ltd.) *Q:IPM-EX (Nippon Surfactant Industries Co., Ltd.) *R: Salakos 816T (manufactured by Nisshin Oillio Group) *S: SEPIGEL 305 (SEPIC) (Manufacturing method) (1): Heat ingredients (8) to (14) to 90°C and mix until uniformly dissolved. (2): Heat ingredients (5) to (7), (15), and (16) to 70°C, mix and dissolve uniformly, and then mix with (1). (3): Add 30% water to ingredients (4) and (17) to (19), heat to 70°C, and mix until uniformly dissolved. (4) At 70°C, the mixture obtained in (2) is added to the mixture obtained in (3) while stirring, emulsified, and then cooled to room temperature. (5): After adding 10% water to components (1) to (3) and dissolving them, add and mix with (4) to obtain an O / W emulsion type raw material composition. (6): The composition obtained in (5) was spread and molded onto a 50 μm thick polypropylene film using a casting machine while heating and drying to achieve a uniform thickness, and then a 400 μm thick gel sheet for application to the skin was made, which was then cut into a magatama shape.

[0114] The gel sheet for skin application of Example 19 was excellent in all of "transferability to skin," "compatibility with skin," and "sustained moisturizing effect." The storage modulus was 20,000 Pa or less. The mass ratio of component (C) to component (A) ((C) / (A)) was 15.

[0115] Example 20: Gel sheet for skin application (components) (mass%) 1. Nicotinamide 5.0 2. Sodium alginate (ingredient (A)) 7.0 3. Glycerin (ingredient (C)) 65.0 4. 1,3-Butylene glycol (ingredient (C)) 5.0 5. Ethylene-propylene copolymer (melting point 95°C) (component (B): solid oil) *T 2.0 6. Cetostearyl alcohol (melting point 50-63°C) (ingredient (B): solid oil) 3.0 7. Macadamia nut fatty acid phytosteryl (ingredient (B): semi-solid oil) *U 2.0 8. Polybutene (viscosity at 30°C: 400,000mm 2 / s) (Component (B): Liquid oil) 1.0 9. Octyldodecanol (Component (B): Liquid oil) *W 1.0 10. Liquid paraffin (component (B): liquid oil) *X 5.0 11. Hydrogenated lecithin (ingredient (G)) *13 1.0 12. Polyoxyethylene phytosterol (ingredient (G)) *Y 0.3 13. Purified water remaining (4.7) *T: EP-700 (manufactured by BakerPetrolite) *U: PLANDOOL-MAS (manufactured by Nippon Fine Chemicals) *W: Lisonol 20SP (Kyukyu Alcohol Kogyo Co., Ltd.) *X: KLEAROL WHITE MINERAL OIL (manufactured by Sonneborn) *Y: Nikkor BPS-30 (Nikko Chemicals) (Manufacturing method) (1): Heat ingredients (5) to (10) to 90°C and mix until uniformly dissolved. (2): Heat ingredients (3), (4), (11), and (12) to 70°C, mix and dissolve uniformly, and then mix with (1). (3): Add 30% water to ingredient (2), heat to 70°C, and mix until uniformly dissolved. (4) At 70°C, the mixture obtained in (2) is added to the mixture obtained in (3) while stirring, emulsified, and then cooled to room temperature. (5): After adding 10% water to component (1) and dissolving it, add it to (4) and mix to obtain an O / W emulsion type raw material composition. (6) A polyvinylidene chloride film was placed on the bottom of a polystyrene tray with a magatama-shaped depression, and the composition obtained in (5) was poured onto it. The film was then heated and dried at 60°C for one hour to obtain a 200 μm-thick gel sheet for application to the skin.

[0116] The gel sheet for skin application of Example 20 was excellent in all of "transferability to skin," "compatibility with skin," and "sustained moisturizing effect." The storage modulus was 20,000 Pa or less. The mass ratio of component (C) to component (A) ((C) / (A)) was 10.

Claims

1. The following components (A) to (C): (A) 0.1 to 20% by mass of at least one selected from alginic acid (salt), fucoidan, agarose, and carrageenan (B) Oil agent 1 to 40 mass% (C) Polyhydric alcohol 40 to 90% by mass and a water content of 10% by mass or less.

2. 2. The gel sheet for application to skin according to claim 1, wherein the component (B) comprises an oil that is solid or semi-solid at 25°C.

3. 3. The gel sheet for application to skin according to claim 1, wherein the mass ratio of the component (C) to the component (A) ((C) / (A)) is 5 or more.

4. The gel sheet for application to skin according to any one of claims 1 to 3, wherein the component (C) comprises glycerin.

5. The gel sheet for application to skin according to any one of claims 1 to 4, wherein the component (A) is an alginate.

6. The gel sheet for application to skin according to any one of claims 1 to 5, further comprising a component (E) of at least one selected from polyvinyl alcohol and polyvinylpyrrolidone.

7. Further, the composition contains 0.01 to 10% by mass of an active ingredient (F), 7. The gel sheet for application to skin according to any one of claims 1 to 6, wherein the active ingredient is at least one selected from the group consisting of nicotinamide, dipotassium glycyrrhizinate, vitamin C (ascorbic acid), L-ascorbic acid 2-glucoside, citric acid, and tranexamic acid.

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