WO2009038030A1

WO2009038030A1 - Gel sheet and sheet-like cosmetic material using the same

Info

Publication number: WO2009038030A1
Application number: PCT/JP2008/066614
Authority: WO
Inventors: Shigetomo Tsujihata
Original assignee: Fujifilm Corporation
Priority date: 2007-09-20
Filing date: 2008-09-09
Publication date: 2009-03-26

Abstract

The invention provides the gel sheet comprising a hydrogel which comprises an ether-based temperature-sensitive polymer, and at least one of collagen or decomposition products of collagen; and the sheet-like cosmetic material using the gel sheet described above.

Description

DESCRIPTION

GEL SHEETAND SHEET-LIKE COSMETIC MATERIAL USING THE SAME

TECHNICAL FIELD

[0001] The present invention relates to a gel sheet used in the fields such as pharmaceuticals, quasi-drugs, cosmetics, sanitary materials, and miscellaneous goods, and a sheet-like cosmetic material using the gel sheet. BACKGROUND ART

[0002] Gel sheets are used for a pack material and an adhesive agent used for the beauty and facial treatments and skin therapies; carriers for active ingredients such as a skin permeable component, and an antiphlogistic analgetic; an adhesive tape for living bodies aimed at the protection against wound or the fixation of drug; and an injury-covering agent. These gel sheets protect the surface of the skin by adhering on the surface of the skin, impart a water retentivity to the skin surface, and contain various ingredients in the gel sheet, thereby imparting a water content (water retentivity) and controlling the temperature of the skin, or exhibiting functions for supplying active ingredients in the gel sheet to living bodies. In particular, an increase in the temperature and water content of the skin can promote the migration of active ingredients due to permeation of the active ingredients in a sheet into the skin.

[0003] It has been known that a gel sheet having such a function contains collagen, and polysaccharides such as chitin, chitosan, alginic acicl and cellulose, as a constituent component (for example, see, Japanese patent Application Laid-Open (JP-A) No. 3-81213). [0004] Meanwhile, as a temperature-sensitive change-of-state hydrogel composition, a technology, in which a drug in a hydrogel is medicated into the skin due to the change of the state from the gel to a flowable state by the body temperature when the hydrogel contacts the skin, has been known (for example, see, Published Japanese Translation of PCT International Publication for Patent Application (JP-T) No. 2007-502269). Further, an adhesive sheet comprising a temperature-responsive polymer having a transition temperature of from 4 to 34⁰C and an adhesive polymer (for example, see, JP-ANo. 5-184657), and a temperature-responsive gel sheet recognized in a temperature-responsive hydrogel formed from a particular polyether ester, (for example, see, JP-ANo. 11-92554) have been known.

However, these gel sheets are insufficient for rapidly medicating active ingredients or the like in a gel, into the skin, and in many cases, the sheets are inferior in handling characteristics.

DISCLOSURE OF INVENTION

[0005] In view of the above circumstances, an object of the present invention is to provide a gel sheet having improved permeability with respect to water or active ingredients upon contacting an adherend such as an epidermis and the like, and excellent handling characteristics, and a sheet-like cosmetic material using the gel sheet. [0006] A first aspect of the invention provides a gel sheet comprising a hydrogel which comprises an ether-based temperature-sensitive polymer, and at least one of collagen or decomposition products of collagen.

A second aspect of the invention provides a sheet- like cosmetic material using any one of the gel sheets described above. [0007] The invention can provide a gel sheet and a sheet-like cosmetic material using the gel sheet with an improved permeability of water or active ingredients in the sheet by bringing the gel sheet into contact with an adherend such as the epidermis and the like, and excellent handling characteristics.

BEST MODE FOR CARRYING OUT THE INVENTION

[0008] The gel sheet of the present invention contains an ether-based temperature-sensitive polymer, and at least one of collagen and decomposition product thereof.

The ether-based temperature-sensitive polymer of the above gel sheet is preferably at least one selected from the group consisting of polyethers, polyvinyl ethers, and alkylated polysaccharide derivatives, more preferably a block polymer containing polyethylene oxide and polypropylene oxide.

The gel sheet may contain an O/W type emulsion, and the O/W type emulsion may contain a carotenoid.

[0009] Further, the gel sheet of the present invention is preferably those that a syneresis liquid of the gel sheet contains the emulsified particles of the O/W type emulsion.

The gel sheet of the present invention preferably comprises a hydrogel layer containing the hydrogel and a sheet-like substrate provided in the hydrogel layer or adjacent to the hydrogel gel layer.

The invention will be described below.

Any notation for expressing numerical range in the invention indicates a range defined by the minimum and maximum values both inclusive. [0010] In the invention, the "gel sheet" includes gel sheets used for a pack material and an adhesive agent used for the beauty and facial treatments and skin therapies, carriers for active ingredients such as a skin permeable component, an antiphlogistic analgetic, an adhesive tape for living bodies aimed at the protection against wound or the fixation of drug, and an injury-covering agent, and refers to a sheet which retains active ingredients or water, and is used by directly adhering the sheet to an adherend for the purpose of permeating the retained components to the adherend. The gel sheet is useful as cosmetic materials such as a pack agent for being adhered onto the skin to provide the skin with water or active ingredients. [0011] [Gel sheet]

The gel sheet of the invention contains a gel sheet containing an ether-based temperature-sensitive polymer, and at least one of collagen and decomposition product thereof.

The ether-based temperature-sensitive polymer used in the invention causes the dehydration with an increase in temperature. On the other hand, the conformation of collagen or gelatin which is a decomposition product of collagen varies with an increase in temperature. The combined use of the ether-based temperature-sensitive polymer and collagen or its decomposition product having such properties enables the control of a releasing amount of active ingredients such as medical properties contained in the hydrogel, and the maintenance of an appropriate shape strength of the hydrogel. Accordingly, the gel sheet containing the hydrogel is useful for a sheet-like cosmetic material for providing moisture-retaining property and for permeating active ingredients into the skin. [0012] (Hydrogel) < Ether-based Temperature-Sensitive Polymer >

The hydrogel used for the invention contains an ether-based temperature-sensitive polymer.

The ether-based temperature-sensitive polymer of the invention refers to a polymer which hydrates at a certain temperature or less in the presence of water, and when this temperature is exceeded, dehydrates and thereby undergoes a conformation change. These microscopic changes induced by the temperature changes appear as macroscopic changes such as a change in volume, a hydrophilic-hydrophobic change, an optical change, a swelling-contraction change and the like.

[0013] The "certain temperature" is referred to as the temperature of the lower critical consolute temperature, and from the viewpoint of an increase in the skin permeability of water or active ingredients when adhering the gel sheet to living bodies, the temperature is preferably from 20 to 40°C, and more preferably from 25 to 30°C. [0014] The ether-based temperature-sensitive polymer used in the invention has the above temperature-sensitive characteristic, and any polymer can be used without limitation as long as the polymer has an ether bond. From the viewpoint of the compatibility of the responsiveness to temperature and the stability during storage, the ether-based temperature-sensitive polymer has preferably a weight average molecular weight (Mw) of from 5,000 to 1,000,000, and more preferably from 10,000 to 500,000.

In particular, from the viewpoint of the responsiveness to the temperature of living bodies and the affinity with a substrate material, at least one of ether-based temperature-sensitive polymers selected from the group consisting of polyethers, vinylethers and alkylated polysaccharide derivatives is preferable, and examples thereof include the following compounds:

[0015] As polyethers, for example, polyethylene oxide, polypropylene oxide, polyethylene oxide/polypropylene oxide block copolymer, polyethylene oxide/polypropylene oxide/polyethylene oxide block copolymer, and the like can be preferably exemplified.

[0016] As polyvinyl ethers, for example, polymethyl vinylether, polyethyl vinylether, polymethoxyethyl vinylether, polyethoxyethyl polyvinylether, and the like can be preferably exemplified.

[0017] As alkylated polysaccharide derivatives, for example, methylcellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, hydroxypropyl methylcellulose, ethyl cellulose, hydroxypropyl chitosan, and the like can be preferably exemplified. [0018] Further, from the viewpoint of the responsiveness to the temperature of living bodies and the affinity with a substrate material, the polyethers, polyvinylethers and alkylated polysaccharide derivatives have preferably at least one or more functional groups selected from the group consisting of an oxyethylene group, an oxypropylene group, a methoxy group and an ethoxy group, and in the above examples, polyethylene oxide/polypropylene oxide block copolymer, polyethylene oxide/polypropylene oxide/polyethylene oxide block copolymer, polymethyl vinylether, methylcellulose, and the like are preferable.

[0019] As the ether-based temperature-sensitive polymer of the invention, a block polymer containing polyethylene oxide and polypropylene oxide is particularly preferable, and more specifically, polyethylene oxide/polypropylene oxide block copolymer (hereafter, simply referred to as "PEO-PPO block polymer"), or polyethylene oxide/polypropylene oxide/polyethylene oxide block copolymer (hereafter, simply referred to as "PEO-PPO-PEO block polymer") is desirable. These polyethers are known as a poloxamer, and are easily available as commercial products, under the trade name of "PLURONIC" and "LUTROL (both are manufactured by BASF A.G.), NEWPOL (manufactured by Sanyo Chemical Industries, Ltd.), and EPAN (manufactured by Dai-Ichi Kogyo Seiyaku Co., Ltd.), PRONON (manufactured by Nippon Oil & Fats Co., Ltd.), and the like. The above ether-based temperature-sensitive polymer can be used singly, or a mixture of two or more can be used [0018] The content of the ether-based temperature-sensitive polymer in the hydrogel used in the invention is preferably from 0.05 to 20% by mass, more preferably from 0.1 to 10% by mass, and particularly preferably from 0.2 to 5% by mass.

[0020] When the content of the ether-based temperature-sensitive polymer is 0.05% by mass or more, the effect of an increase in permeation of active ingredients added in the hydrogel into the skin can be sufficiently achieved, and when the content is 20% by mass or less, a remarkable reduction in the storability of the hydrogel can prevented. [0021 ] < Collagen and Decomposition Product >

The hydrogel used in the invention includes collagen and the decomposition product thereof.

Collagen herein is not specifically limited, but includes various collagen extracts. Extraction can be performed using collagen-containing raw materials by known techniques such as acid solubilization, alkali solubilization, neutral salt solubilization and enzyme solubilization. As far as the materials contain collagen, any materials can be used, and the skin, scale, bone, gristle, tendon and vertebrata (for example, cattle, pig, sardine, shark and the like) can be exemplified, and in view of a high content of collagen, bones, gristles, skins or scale, tendons, placentae and the like can suitably be used. In particular, collagen used suitably in the invention is preferably water-soluble collagen. The decomposition products of collagen in the invention can be obtained by decomposing the collagen with a proteolytic enzyme such as collagenase, trypsin, and chymotrypsin, or by hydrolyzing with an acid or an alkali, or by denaturing with heat.

[0022] As collagen decomposition products, for example, acid-processed gelatin, alkali-processed gelatin, enzyme decomposition gelatin, collagen tripeptide, collagen dipeptide, and amino acids (glycine, proline, hydroxyproline, acetylhydroxyproline and the like) are exemplified.

[0023] In the invention, in view of releasing active ingredients, at least one of gelatin or gelatin derivatives is preferable among the collagen and the decomposition products of collagen.

[0024] The gelatin is a hydrolyzed protein of collagen. The production methods of the gelatin are not specifically limited, and the gelatin is commonly manufactured by a acid process or an alkali process from cattle bones, cattle skins, pig skins and fish scale, and the like as raw materials, but may be manufactured by an enzyme method.

[0025] Further, as gelatin derivatives, known derivatives can be used. For example, acid anhydride adducts of gelatin (for example, phthalated gelatin, succinated gelatin, trimellited gelatin and the like), lactone adducts (glucono-δ-lactone adduct gelatin, and the like), acylated gelatin (acetylated gelatin, and the like), esterified gelatin (methylesterified gelatin, and the like), organic acid salt of gelatin (gelatin acetate, gelatin stearate, gelatin benzoate), and the like are exemplified.

[0026] As the gelatin and the derivatives thereof used for the gel sheet of the invention, gelatin derived from pig skin, gelatin derived from fish, succinated gelatin, phthalated gelatin, and trimellited gelatin are desirable from the viewpoint of the affinity with living bodes and the releasing property of active ingredients.

[0027] As the gelatin and the derivatives thereof, a gelatin may be used singly, or a combination of two or more of gelatins may be used, a gelatin derivative may be used singly, or a combination of two or more of gelatin derivatives may be used, or a mixture of gelatin and gelatin derivatives may be used.

[0028] Furthermore, the weight average molecular weight of the gelatin and gelatin derivative in the invention is preferably from 5,000 to 1,000,000, more preferably from 5,000 to 300,000, and particularly preferable from 10,000 to 300,000, as the weight average molecular weight measured by the gel permeation chromatography (GPC). [0029] The content of the collagen and the decomposition product of collagen contained in the hydrogel in the invention is preferably from 0.05 to 20% by mass, more preferably from 0.1 to 10% by mass, and particularly preferable from 0.2 to 5% by mass. The content of the collagen and decomposition product of collagen of 0.05% by mass or more is effective to the permeability of active ingredients in the hydrogel into the skin, and when the content is 20% by mass or less, the handling characteristics become good.

Furthermore, the mass ratio of the ether-based temperature-sensitive polymer to the collagen and decomposition product thereof (ether-based temperature-sensitive polymer : collagen and decomposition product thereof) is preferably from 1:50 to 50:1, more preferably from 1 : 10 to 10: 1 , and particularly preferably from 1 :5 to 5:1 in view of the permeability of active ingredients into the skin.

[0030] In order to exert various effects, the gel sheet of the invention further contains preferably other components such as polyhydric alcohol compounds, an O/W type emulsion, and polysaccharides, in the hydrogel. Furthermore, a hydrophilic polymer and the like may also be contained, if needed. [0031 ] < Polyhydric Alcohol Compound >

From the viewpoint of the permeability of active ingredients into the skin and the storability, the gel sheet of the invention preferably further contains polyhydric alcohol compounds.

[0032] The polyhydric alcohol compounds include, specifically, glycerins (glycerin, diglycerin and the like); glycols (for example, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3 -propanediol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1 ,2-pentanediol, 1,2-hexanediol, 1 ,2-octanediol, and the like), saccharides (glucose, fructose, mannose, galactose, xylose, arabinose, glucosamine, N-acetylglucosamine, sucrose, lactose, maltose, isomaltose, trehalose, cellobiose, kojibiose, sophorose, maltotriose, raffinose, stachyose, and the like), sugar alcohol (glycerol, threitol, erythritol, arabinitol, xylitol, ribitol, mannitol, sorbitol, galactitol, inositol, and the like) are exemplified. The above polyhydric alcohol compound may be used singly, or a mixture of two or more may be used. [0033] Among them, glycerins or glycols are preferably used in the gel sheet of the invention, in particular, glycerin, 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, and 1,3-butanediol are more desirable. Furthermore, glycerin, 1,2-propanediol, 1,3-butanediol, and 1,2-hexanediol are particularly preferably used. [0034] The ratio of the polyhydric alcohol compounds contained in the hydrogel in the invention is preferably 50% by mass or less, and particularly preferably from 1 to 20 % by mass.

The ratio of the polyhydric alcohol compounds contained in the hydrogel in the invention is preferably 50% by mass or less, thereby preventing reduction in the gel strength, and improving handling characteristics. [0035] < O/W Type Emulsion >

The gel sheet of the invention contains preferably an O/W type emulsion. In particular, an O/W type emulsion containing oil-soluble active ingredients and medicinal properties is preferable. In this manner, the components in the O/W type emulsion can be supplied to an adherend, so that the function of each component, for example, making the skin beautiful, can be enhanced by the skin permeation.

[0036] As oil-soluble active ingredients, for example, lipid soluble vitamins and their related substances (tocopherol, tocotrienol, retinol, retinal, calciferol, and the like), sterols (cholesterol, phytosterol, and the like), ubiquinones (CoQlO and the like), and a sphingolipid, a ceramide, a oryzanol, a squalene, a squalane, a carotenoid, and the like, and derivatives thereof are still desirable, and in the invention, the carotenoid is especially preferable.

[0037] As the carotenoid, actinioerythrol, astaxanthin, bixin, canthaxanthin, capsanthin, β-8'-apo-carotenal, β-12'-apo-carotenal, α-carotene, β-carotene, γ-carotene, β-cryptoxanthin, lutein, lycopene, violaxantin, zeaxanthin, fucoxanthin, and derivatives thereof are exemplified.

Among them, astaxanthin, lutein, zeaxanthin and β-cryptoxanthin are especially desirable, and astaxanthin, for which an antioxidant effect, an anti-inflammatory effect, an antiaging skin-care effect and a whitening effect are recognized, is particularly desirable. [0038] In addition, other components such as an emulsifier, which can generally be contained in each phase of an emulsion, may be contained in the O/W type emulsion composition in an amount of being generally used. In such other components, other components such as polyhydric alcohols described in the present specification are included.

[0039] The volume average particle diameter of the emulsified particles of the O/W type emulsion, is preferably from lnm to 200nm, more preferably from lnm to 150nm, and particularly preferably from lnm to lOOnm. [0040] The volume average particle diameter can be measured with a commercial particle size distribution analyzer or the like. As the particle size measuring method of an emulsion, an optical microscopic method, a confocal laser scanning microscopic method, an electron microscopic method, an atomic force microscopic method, a static light scattering method, and a laser diffraction method, a dynamic light scattering method, a centrifugal sedimentation method, an electric pulse measuring method, a chromatographic method, an ultrasonic attenuation method, and the like are known, and apparatuses according to each measuring principle are on the market.

[0041] In view of the range of the volume average particle diameter and the ease of the measurement thereof in the invention, the dynamic light scattering method is desirable for the measurement of the volume average particle diameter of the emulsion in the invention. As the commercial measuring device using the dynamic light scattering method, NANOTRAC UPA (Nikkiso Co., Ltd.) and a dynamic light scattering particle size distribution analyzer LB-550 (Horiba, Ltd.), a thickened system particle size analyzer FPAR-1000 (Otsuka Electronics Co., Ltd.), and the like are exemplified. [0042] In the invention, the values of the volume average particle diameter of the O/W type emulsion measured at 25°C by the thickened system particle size analyzer FPAR-1000 (manufacture by Otsuka Electronics Co., Ltd.), are adopted.

[0043] In the method of measuring the volume average particle diameter, the volume average particle diameter is measured with a measurement glass tube in such a manner that the emulsion is diluted with pure water so that the concentration of the oil phase becomes from 0.1 to 1% by mass. The volume average particle diameter can be obtained as an accumulative value (50%) when the refractive index of the dispersion medium is set to 1.3313 (pure water), and the viscosity of the dispersion medium is set to 0.8846mPa s (pure water).

[0044] The method of producing the O/W type emulsion is not specifically limited, but, for example, the methods described in JP-A No. 2005-75817 can be used. Alternatively, the OAV type emulsion is preferably produced by a method comprising the steps of (a) forming a water phase prepared by dissolving a water-soluble emulsifier in an aqueous medium, (b) forming an oil phase by mixing and dissolving a carotenoid, a tocopherol, a lecithin, and optionally other oils and fats, and (c) mixing and emulsifying the water phase and the oil phase with stirring.

[0045] When emulsifying, it is particularly preferable that after emulsifying by the use of a usual emulsifying machine utilizing a shearing action with a stirrer, an impeller agitation, a homomixer, and a continuous circulation type shearing machine, the emulsion is further emulsified by being passed through a high pressure homogenizer or the like, so that two or more of emulsifying machines are used in combination. By the use of the high pressure homogenizer, an emulsion containing liquid droplets with a more uniform fine particle size can be obtained.

[0046] The content of the O/W type emulsion in the hydrogel of the invention is preferably from 0.001 to 10% by mass, and more preferably from 0.05 to 1% by mass, from the viewpoint of the effects and permeation of active ingredients into the skin. Further, the content of oil soluble active ingredients in the hydrogel of the invention is preferably from 0.0001 to 10% by mass, and more preferably from 0.05 to 5% by mass, although the content of the oil-soluble active ingredients varies with the kind of the active ingredient.

[0047] When the oil-soluble active ingredient is a carotenoid, the content of the carotenoid in the hydrogel of the invention is preferably from 0.0001 to 0.5% by mass, more preferably from 0.0005 to 0.1% by mass, and particularly preferably from 0.001 to 0.05% by mass. When the content of the carotenoid is 0.0001% by mass or more, the effects (making the skin beautiful or the like) after adhering the gel sheet of the invention onto the skin are felt, and when the content of the carotenoid is 0.5% by mass or less, unpleasant feelings are not apt to arise due to suppression of coloration of the skin. [0048] < Polysaccharide >

It is desirable that a polysaccharide is added to the gel sheet of the invention for improving the handling characteristics thereof.

The polysaccharides which can be used for the invention, include polysaccharides other than the above ether-based temperature-sensitive polymer, for example, neutral polysaccharides (for example, cellulose, amylose, amylopectin, agarose, dextran, pullulan, inulin, galactan, mannan, xylan, arabinan, glucomannan, galactomannan, and the like), and anionic polysaccharides (pectic acid, alginic acid, agar, carragheenan, fucoidan, hyaluronic acid, a chondroitin sulfate, heparin, gellan gum, native gellan gum, xanthan gum, carboxymethylcellulose, and the like), and cationic polysaccharides (chitin, chitosan, cationic cellulose, and the like).

[0049] Among them, polysaccharides with a high thickening gelling action is more preferable, and glucomannan, galactomannan, agar, carragheenan, gellan gum, native gellan gum, and xanthan gum are particularly preferable. In order to increasing the gelling action, two or more of these polysaccharides are used in combination. [0050] The content of the polysaccharide in the hydrogel of the invention is preferably from 0.01 to 5% by mass, more preferably from 0.1 to 4% by mass, and particularly preferably from 0.2 to 2% by mass. [0051] When the content of polysaccharide is 0.01% by mass or more, the insufficiency of the gel strength can be suppressed so that handling characteristics become good, and when the content of polysaccharide is 5% by mass or less, the depression of the skin permeability can be prevented. [0052] < Hydrophilic Polymer >

Known hydrophilic polymer can be added to the hydrogel of the gel sheet used for the invention for the purpose of improving a moisture-retaining property or the like, unless the solubility of the gel at the time of adhering the gel sheet to the skin is impaired. Further, the hydrophilic polymers can also be used for improving the shape stability of the gel sheet.

[0053] The hydrophilic polymers which can be used in the invention may be polymer compounds other than the above ether-base temperature-sensitive polymers and the polysaccharides, and may be either synthetic or natural polymer compounds, as long as the polymer compounds have a hydrophilic functional group (for example, a hydroxyl group, a carboxyl group, a sulfo group, a phospho group, a carbamoyl group, an amino group, an ammonio group, an ethyleneoxy group, and the like). These polymer compounds may be used singly, or a mixture of two or more may be used.

[0054] As the synthetic polymer compounds having a hydrophilic group suitable for the invention, for example, anionic polymer compounds such as a vinyl alcohol(co)polymer, a 2-hydroxyethyl acrylate(co)polymer, an acrylic acid(co)polymer, a methacrylic acid(co)polymer, a maleic acid(co)polymer, an itaconic acid(co)polymer, p-vinyl benzoic acid(co)polymer, 2-acrylamide-2-methyl-l-propanesulfonic acid(co)polymer and a styrene sulfonic acid(co)polymer, as well as an acrylamide(co)polymer, an acryloylmorpholine(co)polymer, an N-vinyl pyrrolidone(co)polymer, a vinyl amine(co)polymer, an N,N-dimethyldiallyl ammonium chloride(co)polymer, a 2-methacryloyloxyethyl ammonium chloride(co)polymer, a polyethylene glycol methacrylate(co)polymer, polyethyleneimine, and the like are exemplified. [0055] The weight average molecular weight of the above hydrophilic polymers is preferably from 1,000 to 500,000, and more preferably from 5,000 to 100,000 from the viewpoint of the moisture-retaining property.

Further, the content of the hydrophilic polymers is preferably from 0.05 to 5% by mass and more preferably from 0.1 to 3% by mass in the hydrogel, from the viewpoint of the moisture-retaining property and handling characteristics. [0056] < Excipient >

An excipient may be preferably added to the hydrogel in the invention, for the purpose of further improvement of the shape stability of the gel sheet. As the excipient, organic or inorganic fine particles can suitably be used. As organic fine particles, known polystyrene particles, polymethacrylate particles, and crystallite cellulose are preferable. Further, as inorganic fine particles, silica, alumina, calcium carbonate, kaolin, clay minerals, titanium oxide and the like are desirable. Among them, silica or clay minerals are preferable, and in particular, vapor phase silica and synthetic smectite having an average particle diameter of 200nm or less are particularly preferable.

The ratio of the excipient contained in the hydrogel in the invention is preferably 10% by mass or less, and particularly preferably from 1 to 5% by mass. [0057] < Fragrance >

In order to enhance the effect of relaxation, a fragrance may be added to the hydrogel of the invention. As the fragrance, an alcohol-based fragrance, a phenol-based fragrance, a carboxylic acid-based fragrance, an amine-based fragrance and the like are exemplified. As the alcohol-based fragrance, leaf alcohol, 3-octenol, 9-decenol, linarool, geraniol, nerol, citronellol, rhodinol, dimethyloctanol, hydroxy citronellol, tetrahydrolinalool, lavandulol, muguol, mycenol, teφineol, 1 -menthol (L-menthol), borneol, isopulegol, tetrahydromuguol, bornylmethoxy cyclohexanol, nobol, farnesol, nerolidol, santalol, sandalol, cedrol, vetiverol, patchouli alcohol, benzyl alcohol, β-phenyl ethylalcohol, γ-phenyl propylalcohol, cinnamic alcohol, anise alcohol, α-amylcinnamic alcohol, dimethylbenzyl carbinol, methylphenyl carbinol, dimethylphenyl carbinol, β-phenylethyldimethyl carbinol, β-phenylethylmethyl ethylcarbinol, phenoxyethyl alcohol, phenyl glycol, t-butylcyclohexanol, and the like are exemplified.

[0058] Further, as phenol-based fragrances, eugenol, vanillin, cypress thiol, and the like, as carboxylic acid-based fragrances, cinnamic acid, phenyl acetic acid, hydrocinnamic acid and the like, and as amine-based fragrances, indole, skatole, 2-methyl tetrahydroquinoline, 6-methylquinoline and the like, are exemplified. [0059] < Antiseptics >

The gel sheet of the invention preferably further contains antiseptics for the purpose of the measure to deterioration by microbes. Antiseptics include, for example, phenol, benzoic acid and the salts thereof, salicylic acid and the salts thereof, p-hydroxybenzoates (methyl paraben, ethyl paraben, propyl paraben, butyl paraben), 2-phenoxyethanol, dehydroacetic acid and the salts thereof, sorbic acid and the salts thereof, alkylamino ethylglycine chloride, triclosan, benzalkonium chloride, ethanol, propanol, butanol, and the like. These compounds may be used singly, but are preferably used in combination. Among them, p-hydroxybenzoates and phenoxy ethanol are particularly preferable.

[0060] The content of the antiseptics in the invention is preferably from 0.01 to 0.5% by mass, more preferably from 0.02 to 0.3% by mass, and particularly preferably from 0.03 to 0.2% by mass.

[0061] < Organic Acid >

The hydrogel of the invention may also further contain an organic acid from the viewpoint of controlling the pH value thereof. Specifically, the organic acid includes acetic acid, α-hydroxy acid (for example, citric acid, lactic acid, gluconic acid, malic acid, succinic acid and the like), ascorbic acid, pyrrolidone carboxylic acid and the like. These compounds may be used singly, or a mixture of two or more may be used. The content of these compounds is preferably from 0.01 to 5% by mass, and more preferably from 0.05 to 2% by mass in the hydrogel. [0062] < Other Active Ingredients >

The gel sheet of the invention may further contain various kinds of active ingredients or additives in accordance with the intended use of the sheet. As such active ingredients or additives, the following compounds are exemplified: antioxidants (tocopherols, dibutyl hydroxytoluene, butyl hydroxyanisol, gallates, flavonoid, tannin, lignan, saponin and the like);

[0063] ultraviolet absorbers (p-methoxy cinnamic acid, octyl p-methoxycinnamate, 2-methoxy-2-hydroxybenzophenone, 2-ethylhexyl-p-dimethylaminobenzoate, and the like); pH adjusters (buffers such as lactic acid-sodium lactate, citric acid-sodium citrate, succinic acid-sodium succinate, and the like); chelating agents (phytic acid, ethylenediamine tetraacetic acid, and the like); [0064] surfactants (polyglycerin fatty acid esters, sucrose fatty acid esters, lecithin, and the like); vitamins (vitamin A, B₁, B₂, B₆, C, D, E, and derivatives thereof, pantothenic acid, biotin, nicotinic acid amide, vitamin-C ester, and the like);

[0065] amino acids (glycine, trimethyl glycine, pyrrolidone carboxylic acid, serine, carnitine, γ-amino butyric acid, taurine, threonine, asparagine, glutamine, thyrosin, lysine, histidine, arginine, aspartic acid, glutamic acid, ornithine, valine, leucine, and the like); antiphlogistics (glycyrrhitic acid derivatives, glycyrrhetic acid derivatives, salicylic acid derivatives, cypress thiol, zinc oxide, allantoin, and the like);

[0066] moisturizers (urea, casein, soybean peptide, lactobacllus fermentation metabolism products, yeast fermentation metabolism products, honey, lactoferrin, albumin, hydrolyzed elastin, hydrolyzed keratin, hydrolyzed silk, α-hydroxy acid salt (for example, sodium lactate, potassium lactate, potassium gluconate, and the like), sodium pyrrolidone carboxylate, betaine and whey, and the like);

[0067] whitening agents (ascorbic acid glucoside, 3-O-ethyl ascorbic acid, arbutin, hydroquinone, kojic acid, lucinol, tranexamic acid, adenosine- 1 -sodium phosphate, magnolignan, ellagic acid, retinoid, rutin, resolcinol, cysteine, glutathione, linolic acid, and the like);

[0068] various extracts (for example, angelica keiskei extract, persea gratissima (avocado) fruit extract, hydrangea serrata leaf extract, althea extract, arnica extract, aloe extract, prunus armeniaca (apricot) kernel extract, prunus armeniaca (apricot) kernel extract, ginkgo biloba extract, foeniculum vulgare (fennel) extract, turmeric extract, oolong tea extract, rose fruit extract, echinacea angustifolia leaf exract, Scutellaria baicalensis root extract, phellodendron bark extract, coptis japonica root extract, hordeum vulgare seed extract, hypericum perforatum extract, lamium album extract, nasturtium officinale extract, citrus aurantium dulcis (orange) fruit extract, dehydrated seawater, seaweed extract, hydrolyzed elastin, hydrolyzed wheat powder, hydrolyzed silk, chamomilla recutita (matricaria) extract, daucus carota sativa (carrot) root extract, artemisia capillaris flower extract, glycyrrhiza extract, hibiscus tea extract, pyracantha fortuneana fruit extract, actinidia chinensis (kiwi) fruit extact, cinchona extract, cucumis sativus (cucumber) fruit extract, guanosine, gardenia florida extract, sasa veitchii extract, sophora angustifolia root extract, walnut shell extract, citrus grandis (grapefruit) fruit extract, clematis vitalba leaf extract, chlorella vulgaris extaract, morus alba leaf extract, gentiana lutea extract, black tea extract, yeast extract, arctium lappa root extract, fermented rice bran extract, oryza stiva (rice) germ oil, Symphytum officinale leaf extract, vaccinium vitis-idaea leaf extract, asiasarum root extract, family of bupleurum extract, umbilical cord extract, saponaria officinalis extract, bumboo extract, Crataegus cuneata fruit extract, zanthoxylum fruit extract, corthellus shiitake (mushroom) extract, rehmania root extract, lithospermum erythrorhizone root extract, perilla herb extract, linden flower extract, spiraea ulmaria flower extract, peony root extract, acorus calamus root extract, birch extract, equisetum arvense extract, hedera helix (ivy) extract, Crataegus oxyacantha extract, sambucus nigra flower extract, achillea millefolium extract, mentha piperita (peppermint) leaf extract, salvia officinalis (sage) leaf extract, malva sylvestris (mallow) extract, cnidium officinale root extract, swertia japonica extract, glycine soja (soybean) seed extract, jujube fruit extract, thymus vulgaris (thyme) extract, green tea extract, eugenia caryophyllus (clove) flower extract, Imperata cylindrical extract, citrus unshiu peel extract, Japanese angelica root extract, calendula officinalis flower extract, peach kernel extract, bitter orange peel extract, houttuynia cordata extract, solanum lycopersicum (tomato) extract, fermented soybeans extract, panax ginseng root extract, allium sativum (garlic) extract, rosa canina fruit extract, hibiscus sabdariffa flower extract, ophiopogonis tuber extract, carum petroselinum (parsley) extract, honey, hamamelis virginiana (witch hazel) extract, parietaria officinalis extract, isodonis japonicus extract, bisabolol, eriobotrya japonica extract, coltsfoot extract, butterbur sprout extract, poria cocos extract, ruscus aculeatus root extract, vitis vinifera (grape) fruit extract, propolis, luffa cylindrica fruit extract, carthamus tinctorius (safϊlower) flower extract, peppermint extract, tilia platyphyllos flower extract, paeonia sufrruticosa root extract, humulus lupulus (hops) extract, pinus sylvestris cone extract, aesculus hippocastanum (horse chestnut) extract, lysichiton camtschatcense extract, sapindus mukurossi peel extract, melissa officinalis (balm mint) leaf extract, prunus persica (peach) leaf extract, centaurea cyanus flower extract, eucalyptus leaf extract, saxifraga sarmentosa extract, citrus junos fruit extract, coix seed extract, mugwort leaf extract, lavandula angustifolia (lavender) extract, pyrus malus (apple) fruit extract, lactuca scariola sativa (lettuce) extract, citrus medica limonum (lemon) extract, astragalus sinicus extract, rosa centifolia flower extract, rosamarinus officinalis (rosemary) leaf extract, anthemis nobilis flower extract, royal jelly extract, iris extract, lilium candidum bulb extract, crocus sativus flower extract, zingiber officinale (ginger) root extract, capsisum tincrure extract, placenta extract, coix lachryma-jobi (Job's tears) seed extract, citrus junos seed extract, vitis vinifera (grape) seed extract, watercress extract, epiphyllum oxpetalum flower extract, white lupin extract, comb extract, and the like;

[0069] activation agents (for example, royal jelly, sensitizer, cholesterol derivatives, and the like); blood circulation accelerators (for example, nonylic acid valenylamide, nicotinic acid benzylester, nicotinic acid β-buthoxy ethyl ester, capsaicin, zingerone, cantharis tincture, ichthammol, tannic acid, α-borneol, tocopherol nicotinate, inositol hexanicotinate, cyclandelate, cinnarizine, trazoline, acetylcholine, verapamil, cepharanthine, γ-orizanol, and the like; antiseborrheic agents (for example, sulfur, thianthol, and the like), antiinflammatory agents (for example, tranexamic acid, thiotaurine, hypotaurine, εraminocaproic acid, glycyrrhizic acid, β- glycyrrhizic acid, lysozyme chloride, guaiazulene, hydrocortisone, and the like); active ingredients (for example, diisopropylamine dichloroacetate, 4-aminomethyl cyclohexane carboxylic acid, and the like); and,

[0070] further, pyridoxine hydrochloride, nicotinic acid, nicotinic acid derivatives, calcium pantothenate, D-pantothenyl alcohol, acetyl pantothenyl ethylether, isopropyl methylphenol, estradiol, ethynylestradiol, capronium chloride, diphenhydramine hydrochloride,Takanal, camphor, nonylic acid vanillylamide, nonanoic acid vanillylamide, Pirocton-Olamin, glyceryl pentadecanate, 1 -menthol, mononitro guaiacol, resorcin, benzethonium chloride, mexiletine hydrochloride, auxin, female hormone, cantharis tincture, cyclosporin, hydrocortisone, monostearic acid polyoxyethylene sorbitan, peppermint oil, and the like.

Moreover, if administration of medicines to living bodes by the skin permeation is possible, it is also possible to add medicinal properties such as painkillers, tranquilizers, antihypertensives, antibiotics, antihistamines, antimicrobials and the like, to the gel sheet. [0071] One of these active ingredients can be used singly, or a combination of two or more can be used in accordance with the intended use of the gel sheet. The active ingredients contained in the hydrogel according to the invention may further contain the following components. Since these active ingredients and medicinal properties differs in effective dosage depending on the materials thereof, the content of the ingredients and medicinal properties cannot generally be specified, but is generally preferably from 0.001 to 10% by mass, and more preferably from 0.05 to 5% by mass with respect to the total amount of the hydrogel. Further, similarly, in the case of moisturizers, the content thereof is generally preferably from 0.1 to 10% by mass, and more preferably from 0.5 to 5% by mass with respect to the total amount of the hydrogel. [0072] [Structure of Gel Sheet]

As described above, in the gel sheet of the invention, the hydrogel may be formed in a single layer structure, or may also be formed in a multilayered structure with other layers. Further, a plurality of the hydrogel layers may be provided. Each ingredient as described in the above may be contained in the hydrogel layer, or may be contained in other layers, if possible. Furthermore, when the hydrogel layer is formed of plural layers, each of the ingredients may be contained in the same hydrogel layer, or may be contained in the plural layers, separately. Thus, when the gel sheet of the invention is formed of a plurality of hydrogel layers, the content of the above-described ingredients is the quantity contained in all the layers of the hydrogel layer constituting the gel sheet. [0073] < Sheet-like Substrate >

For the purpose of reinforcing the hydrogel layer and improving the handling characteristics of the gel sheet, a sheet-like substrate may be provided in the hydrogel layer or adjacent to the hydrogel gel layer.

The sheet-like substrate is preferably provided from the viewpoint of the shape stability and handling characteristics of the gel sheet of the invention. As other layers other than the hydrogel layer, for example, a support layer or a protective sheet can be exemplified.

The support layer is preferably provided, from the viewpoint of the shape stability and handling characteristics of the gel sheet of the invention, and the protective sheet is preferably provided, from the viewpoint of protecting the surface of the hydrogel layer surface until the use of the gel sheet.

[0074] As the support layer, it is preferable to use known sheet-like substrates such as a nonwoven fabrics, textile fabrics or plastic films, crosslinked gels (gelatin/glutaraldehyde crosslinked gel, polyacrylic acid/polyvalent metal ion crosslinked gel, and the like), and physical gels (agarose gel, κ-carrageenan gel, and the like), and as well as water-insoluble films formed from hydrophilic polymers (chitosan film, cellophane, κ-carragheenan cast film, and the like) and the like.

Among them, in the gel sheet of the invention, it is preferable to use a transparent film generally having a thickness of lOOμm or less from the viewpoint of the shape stability and handling characteristics of the gel sheet, in particular, a water-insoluble film, for example, a chitosan film, cellophane, κ-carragheenan cast film formed from a hydrophilic polymer, and the like are preferable.

[0075] Moreover, as a protective sheet, it is preferable to use a polyethylene film, a polypropylene film, a PET film, and the like, in particular, it is preferable to use a polyethylene film having a thickness of 500μm or less.

[0076] When the gel sheet is formed only from a hydrogel layer, in general, the thickness of the gel sheet is preferably from 0.4 to 3mm, and more preferably from 0.5 to 2mm from the viewpoint of the shape retentivity and the handling characteristics.

Further, although the thickness of the support layer and the protection sheet is described in the above, in the case of the gel sheet with a multilayered structure formed of a hydrogel layer, and a support layer and/or a protective sheet, the thickness of the support layer is still more preferably from 5 to 80μm, and the thickness of the protective sheet is still more preferably from 50 to 500μm. In such a multilayered structure, the thickness of the hydrogel may be the same as that of the thickness of the above-described hydrogel layer, or may suitably be adjusted such that the thickness of the overall gel sheet becomes in the range of from 0.4 to 3mm. [0077] [High Syneresis Gel Sheet]

When the gel sheet of the present invention includes, from among the hydrogels including the above described ingredients, a hydrogel formed by combining an O/W type emulsion which includes emulsified particles having an average diameter of from 1 to 150nm, with a polyether compound (polyethers) as an ether-based temperature-sensitive polymer, and with at least one selected from collagen gels or the decomposition products thereof, it is possible to form a gel sheet having particularly superior syneresis. [0078] In order to rapidly supply the water or the active ingredients contained in the gel sheet to a target region, in addition to the water retentivity of the gel sheet, the syneresis property for supplying water or the like retained in the gel sheet to the predetermined domain of the adjacent adherend is also important. However, known techniques (for example, the techniques described in JP-ANo. 2005-225837, and the techniques described in JP-ANo. 2003-183147), exhibit insufficient syneresis for rapid and efficient permeation of active ingredients contained in the hydrogel into the skin, while maintaining a moisture-retaining property of the skin surface.

[0079] As described in the above, by forming a gel sheet which includes a hydrogel formed by combining an O/W type emulsion containing emulsified particles having an average diameter of from 1 to 150nm, a polyether compound, and collagen and/or the decomposition products thereof, when such a gel sheet contacts water absorptive objects (adherends) such as the skin, the O/W type emulsion containing liposoluble active ingredients is effectively released, and a simultaneous increase in the supply of water content to the keratin layer and the permeability of the active ingredients to the adherend can be obtained.

Furthermore, with a high syneresis gel sheet, in addition to the high syneresis, the sheet is flexible and easily deformable with stress, and since the surface is in a wet state, adhesion with the adherend may also be enhanced.

[0080] The syneresis in the invention refers to the function of exuding a liquid component (syneresis water) contained in the hydrogel, and moving the syneresis water to a living body or an absorbent body which is an adjacent adherend, due to contact between the gel sheet and the adherend. The syneresis water of the gel sheet in the invention contains, in addition to the water content and aqueous-phase components in an emulsion existing in the hydrogel, oil-soluble components or fine solid particles, not only in a water phase, but also in the emulsion particles which exist by being dissolved or dispersed in the liquid component. As a result, various active ingredients in the gel sheet can be effectively supplied to an adjacent adherend by contacting the gel sheet to the adherend.

In addition, in this specification, the gel sheet may be referred to as a "high syneresis gel sheet", particularly when a gel sheet is referred to in the context of syneresis. [0081] The high syneresis gel sheet in the invention can exhibit a syneresis rate of preferably 40% by mass or more, and 90% by mass or less, more preferably 45% by mass or more, and 85% by mass or less, and particularly preferably 50% by mass or more, and 80% by mass or less.

[0082] The syneresis rate in the invention is obtained in such a manner that a gel sheet is cut into a size of 3 cm x 3 cm to form sample gel sheets, and these sample gel sheets are interposed between No.2 filter paper (two kinds of qualitative filter paper stipulated in JIS P3801 (1995 version): 125g/m² and 0.26mm in thickness; freeness time: 80 seconds; water absorbency: 80cm), having a diameter of 9cm manufactured by Advantec MSF. Inc., so as to be two sheets of the filter paper for each of the upper and lower sides of the sample gel sheets, and the change of the mass of the filter paper is measured when allowing to stand under the circumstances of 25°C and the relative humidity of 50±10% for 10 minutes. The syneresis rate is calculated by the formula (1) shown below using the obtained measured values.

Syneresis rate (% by mass) =

(mass of absorbed liquid by filter paper/initial mass of gel) x 100 (1) [0083] In the above formula (1), the "initial mass of gel" is a value obtained by subtracting the mass of the support substrate from the mass of a sample gel sheet test piece. [0084] The method of measuring the syneresis rate can be referred to, for example, the method described on pages 95-102 of "Fragrance Journal" issued in June, 2007. [0085] In the case that the gel sheet of the invention is constituted, for example, as a gel sheet for living bodies, the evaluation of the syneresis rate of the gel sheet based on the amount of liquid absorbed by the filter paper as a water absorptive adherend can be an index whether each component such as water and functional components retained by a hydrogel can permeate into the skin efficiently by being brought a gel sheet into contact with an adherend such as epidermis. When the syneresis rate is less than 40% by mass, the permeation of water or the like into the skin may become insufficient, and when the syneresis rate exceeds 90% by mass, the stability of a gel sheet during storage may be deteriorated.

[0086] Moreover, the concentration of the O/W type emulsion particles in the syneresis liquid is preferably a concentration of from 0.001 to 2 times, more preferably from 0.01 to 1.5 times, and most preferably from 0.1 to 1 times the concentration of the O/W type emulsion particles in the hydrogel. Here, the concentration of the emulsion particles in the syneresis liquid may be roughly estimated from the concentration measured with a colorimeter by use of the filter paper used in measuring the syneresis rate. Moreover, the concentration of the emulsion particles in the syneresis liquid may be roughly estimated with a spectrophotometer, HPLC or the like after an emulsion or oil-soluble components contained in the emulsion is extracted from the filter paper used in measuring the syneresis rate. [0087] The above-descriptions about various components including various kinds of oil-soluble active ingredients and other additives, and the contents thereof, the methods of manufacturing O/W type emulsions, and the like are applicable, without modification, to the O/W type emulsion contained in the high syneresis gel sheet. Further, similarly, unless the primary intended use of each component is impaired, other components, which can be contained in each of the oil phase and the water phase of an emulsion, may be contained in each phase of the O/W type emulsion.

The high syneresis gel sheet can contain an emulsion with fine particles containing oil-soluble active ingredients in the syneresis liquid at high concentrations, so that the active ingredients can efficiently be supplied to an adherend. [0088] As the polyether compounds which can be contained in the high syneresis gel sheet, for example, polyethylene oxide, polypropylene oxide, polyethylene oxide/polypropylene oxide block copolymer, polyethylene oxide/polypropylene oxide/polyethylene oxide block copolymer, and the like can be preferably exemplified, and a block polymer containing polyethylene oxide and polypropylene oxide is particularly preferable, and more specifically, polyethylene oxide/polypropylene oxide block copolymer (hereafter, simply referred to as "PEO-PPO block polymer"), or polyethylene oxide/polypropylene oxide/polyethylene oxide block copolymer (hereafter, simply referred to as "PEO-PPO-PEO block polymer") is particularly preferable. These polyethers are known as a poloxamer, and are easily available as commercial products in the trade name of "PLURONIC" and "LUTROL (both are manufactured by BASF A.G.), NEWPOL (manufactured by Sanyo Chemical Industries, Ltd.), and EPAN (manufactured by Dai-Ichi Kogyo Seiyaku Co., Ltd.), PRONON (manufactured by Nippon Oil & Fats Co., Ltd.), and the like.

In this case, the weight average molecular weight (Mw) of the polyethers is preferably from 1,000 to 1,000,000, and more preferably from 5,000 to 500,000. [0089] In the high syneresis gel sheet, the content of the polyether contained in a hydrogel is preferably from 0.05 to 20% by mass, more preferably from 0.1 to 10% by mass, and particularly preferably from 0.2 to 5% by mass. When the content of the polyether is 0.05% by mass or more in the above-described range, the syneresis can be fully promoted and the effect of an increase in permeation of the active ingredient added in the hydrogel into the skin can be sufficiently achieved, and when the content is 20% by mass or less, a remarkable reduction in the storability can effectively prevented. [0090] Collagens which can be contained in the high syneresis gel sheet are not specifically limited, but include various collagen extracts. Extraction can be performed using collagen-containing raw materials by known techniques such as acid solubilization, alkali solubilization, neutral salt solubilization and enzyme solubilization. As far as the materials contain collagen, any collagen-containing materials can be used, and the skin, scale, bone, cartilage, tendon, organ, and the like, of vertebrata (for example, cattle, pig, sardine, shark and the like) can be exemplified, and in view of a high content of collagen, bones, cartilage, skins or scale, tendons, placentae and the like can suitably be used. In particular, collagen used suitably in the invention is preferably water-soluble collagen. The decomposition products of collagen which can be contained in the high syneresis gel sheet can be obtained by decomposing the collagen with a proteolytic enzyme such as collagenase, trypsin, and chymotrypsin, or by hydrolyzing with an acid or alkali, or by denaturing with heat.

[0091] As the collagen decomposition products, for example, acid-processed gelatin, alkali-processed gelatin, enzyme decomposition gelatin, collagen tripeptide, collagen dipeptide, and amino acids (glycine, proline, hydroxyproline, acetylhydroxyproline and the like) are exemplified.

The content of the collagen or the decomposition products of collagen contained in the hydrogel in the high syneresis gel sheet is preferably from 0.05 to 20% by mass, more preferably from 0.1 to 10% by mass, and particularly preferably from 0.2 to 5% by mass. When the content is 0.05% by mass or more, the water retentive effect by adhering the gel sheet to the epidermis can be attained, and when the content is 20% by mass or less, the handling characteristics become good.

[0092] The hydrogel contained in the high syneresis gel sheet is preferably a hydrogel formed by use of an anionic polymer and a water-soluble divalent metal salt, from the viewpoint of improvement of syneresis property, and the content ratio of the water-soluble divalent metal salt is particularly preferable 5 parts by mass or more with respect to 100 parts by mass of the anionic polymer compounds. [0093] < Water-soluble Divalent Metal Salt >

The hydrogel in the gel sheet of the invention contains preferably a water-soluble divalent metal salt. Here, the water solubility in the invention refers to a solubility of being at least soluble 0.1% by mass in pure water at 25°C.

As the divalent metal for forming a water-soluble divalent metal salt, magnesium, calcium, strontium and barium in the group II of the periodic table, or Cu²⁺, Fe²⁺, Zn²⁺ and Mn²⁺ in the transition metals are exemplified, and magnesium and calcium are preferable. [0094] The water-soluble salts may be any of inorganic salts and organic acid salts, and are not specifically limited. For example, inorganic salts such as hydrochlorides, nitrates, sulfates, phosphates, carbonates and the like, and organic acid salts such as citrates, lactates, malates, succinates, ascorbates, gluconates, and organic and inorganic composite salts such as ascorbyl phosphate salts, are exemplified.

[0095] Among them, magnesium chloride, calcium chloride, magnesium lactate, magnesium malate, magnesium citrate, calcium citrate, magnesium ascorbate, calcium ascorbate, magnesium ascorbyl phosphate, magnesium gluconate, and calcium gluconate are more desirable, and in particular magnesium chloride and magnesium ascorbyl phosphate are preferable.

[0096] The blending amount of the water-soluble divalent metal salt in the high syneresis gel sheet is necessarily 50 parts by mass or more with respect to 100 parts by mass of an anionic polymer compound, which will be described later, (in the present specification, "parts by mass" may be referred to as "parts"), and from the viewpoint of effects, preferably from 50 parts to 1,000 parts, more preferably from 70 parts to 500 parts, and particularly preferably 80 parts to 300 parts.

Further, the content of the water-soluble divalent metal salt in the blended liquid for forming a hydrogel is preferably from 0.1 to 5% by mass, more preferably from 0.2 to 4% by mass, and particularly preferably from 0.5 to 2% by mass. When the ratio of the water-soluble metal salt is in this range, the syneresis from the hydrogel can be improved, the gel sheet with excellent handling characteristics can be obtained. [0097] In the hydrogel formed from an anionic polymer and a water-soluble divalent metal salt, the water-soluble divalent metal salt is used for formation of a gel, and does not necessarily exist in the state of a "salt." However, the content of the water soluble divalent metal salt or the compound derived from the metal salt in the formed hydrogel can be obtained by measuring the quantity of the metal for constituting the metal salt, and by converting the obtained quantity. Accordingly, the "content of water-soluble divalent metal salt in a hydrogel" refers to the value converted in this manner. According to this method, even after a hydrogel is formed, it is possible to detect as to whether the content of the water-soluble divalent metal salt is within the above range. [0098] < Anionic Polymer Compound >

The anionic polymer compounds usable for the high syneresis gel sheet are not specifically limited, and synthetic polymers and natural polymers may be used, as long as the polymer compound contains an anionic group in the molecule selected, for example, from a carboxyl group, a sulfo group, a phospho group and the like.

Only one of these anionic polymer compounds may be used singly, or a mixture of two or more may be used in the hydrogel.

[0099] Anionic synthetic polymer compounds include an acrylic acid(co)polymer, a methacrylic acid(co)polymer, a maleic acid(co)polymer, an itaconic acid(co)polymer, p-vinyl benzoic acid(co)polymer, a 2-acrylamide-2-methyl-l-propanesulfonic acid(co)polymer and a styrene sulfonic acid(co)polymer.

Further, anionic natural polymers compounds include pectic acid, alginic acid, agar, carragheenan, fucoidan, hyaluronic acid, chondroitin sulfate, heparin, gellan gum, native gellan gum, xanthan gum, carboxymethyl cellulose, carboxymethyl starch, carboxymethyl dextran, polyglutamic acid, and further a DNA, RNA and the like. [0100] Among them, an acrylic acid(co)polymer, alginic acid, agar, carragheenan, gellan gum, native gellan gum, xanthan gum, carboxymethyl cellulose, carboxymethyl starch, carboxymethyl dextran, polyglutamic acid, and further a DNA, RNA are preferable. [0101] In particular, as anionic polymer compounds, from the viewpoint of the compatibility of the water retentivity with the gel strength, an acrylic acid(co)polymer, alginic acid, agar, carragheenan, hyaluronic acid, gellan gum, native gellan gum, xanthan gum, carboxymethyl cellulose are preferable, and in particular, agar, carragheenan, gellan gum, native gellan gum, xanthan gum are furthermore preferable. [0102] From the viewpoint of the gel strength, the molecular weight of the anionic polymer compounds is preferably within the range of from 10,000 to 5,000,000, and more preferably within the range of from 20,000 to 2,000,000.

[0103] In the high syneresis gel sheet, the content of the anionic polymer compound in the hydrogel is preferably from 0.01 to 10% by mass, more preferably from 0.1 to 8% by mass, and particularly preferably from 0.2 to 4% by mass. When the content is within these ranges, a hydrogel with a sufficient syneresis can be obtained, while a high gel strength with good handling characteristics can be achieved.

[0104] By using an anionic polymer and a divalent metal water-soluble salt together in combination, a three-dimensional network structure having a weak crosslinked structure is formed in the hydrogel system to be formed, thus it is considered that a sufficient liquid retentivity and an excellent syneresis develop.

[0105] Although the anionic polymer compound and the water-soluble divalent metal salt contained in the hydrogel can be suitably combined in accordance with the intended use, from the viewpoint of compatibility of the gel strength with the syneresis, the combinations of the water-soluble divalent metal salts/anionic polymer compounds can be shown as preferable examples, but the combinations are not limited to these examples: magnesium ascorbyl phosphate /carragheenan; magnesium ascorbyl phosphate /gellan gum; magnesium ascorbyl phosphate /agar; magnesium ascorbyl phosphate /xanthan gum; magnesium ascorbyl phosphate /acrylic acid(co)colymer; magnesium ascorbyl phosphate / carboxymethylcellulose • magnesium chloride /carragheenan, magnesium chloride / gellan gum; magnesium chloride / acrylic acid(co)polymer; magnesium lactate / carragheenan; magnesium lactate / agar; calcium lactate / gellan gum; calcium ascorbate /carragheenan; and calcium gluconate / gellan gum. [0106] < Polyvalent Metal Salt with Trivalence or More >

The content of a polyvalent metal salt with trivalence or more in the hydrogel in a high syneresis gel sheet is preferably 0.1% by mass or less, from the viewpoint of prevention of decrease in the syneresis in a blended solution for forming a hydrogel.

As the polyvalent metal salt with trivalence or more, the salts containing polyvalent metal cations such as Al³⁺, Fe³⁺, Ti³⁺, Ti⁴⁺, In³⁺, Zr⁴⁺, Ta⁵⁺ and the like are exemplified, and more specifically, potassium alum, ammonium alum, iron alum, aluminum sulfate, polyaluminum chloride, synthetic aluminum silicate, aluminum hydroxide, aluminum stearate, aluminum acetate, ferric sulfate, ferric hydroxide, titanium lactate, zirconium acetate, and the like are exemplified. [0107] The content of the polyvalent metal salt with trivalence or more in the hydrogel in the high syneresis gel sheet is preferably 0.1% by mass or less in a blended liquid for forming a hydrogel, more preferably 0.05% by mass or less, and particularly preferably 0.01% by mass or less, and most preferably, the hydrogel does not contain such a polyvalent metal salt except for inevitable impurities. When the content of the trivalent metal salt exceeds 0.1% by mass, there is fear that the syneresis is deteriorated. [0108] < Polysaccharide >

In the high syneresis gel sheet, it is preferable to add polysaccharides other than the anionic polysaccharide described as examples of the above anionic polymer compounds to the hydrogel in order to improve handling characteristics.

To this end, as polysaccharides which can be contained in the high syneresis gel sheet, for example, neutral polysaccharides (for example, cellulose, amylose, amylopectin, dextran, pullulan, inulin, galactan, mannan, xylan, arabinan, glucomannan, galactomannan, agarose, methyl cellulose, hydroxypropyl cellulose, curdlan, xyloglucan and the like), and cationic polysaccharides (chitin, chitosan, cationized cellulose, cationized starch, cationized dextran and the like, are exemplified.

[0109] Among them, polysaccharides with a high thickening gelling action is more preferable, and glucomannan, galactomannan, agarose, methylcellulose, hydroxypropyl cellulose are particularly preferable. In order to increasing the gelling properties furthermore, two or more of these polysaccharides may be used in combination. [0110] The content of the polysaccharides in the hydrogel in the high syneresis gel sheet is preferably from 0.01 to 5% by mass, more preferably from 0.1 to 4% by mass, and particularly preferably from 0.2 to 2% by mass. If the content of the polysaccharides is in the above range, the improvement effect of the gel strength is attained, and handling characteristics are good, the syneresis and decrease in the permeability into the skin, and the like can be prevented. [0111] < Hydrophilic Polymer >

In the high syneresis gel sheet, known hydrophilic polymers can be added to the hydrogel in order to increase moisture-retaining property, unless the solubility of the gel at the time of adhering the gel sheet to the skin is impaired. Further, the hydrophilic polymer can also be used for improvement of the shape stability of the high syneresis gel sheet.

[0112] As the hydrophilic polymer which can be contained in the high syneresis gel sheet, polymer compounds other than the above anionic polymer compound and the polysaccharides, may be either synthetic or natural polymer compounds, as long as the polymer compounds have a hydrophilic functional group (for example, a hydroxyl group, a carbamoyl group, an amino group, an ammonio group, an ethyleneoxy group and the like). These polymer compounds may be used singly, or a mixture of two or more may be used. [0113] As the synthetic polymer compounds having such a hydrophilic group, for example, a vinyl alcohol(co)polymer, a 2-hydroxyethyl acrylate(co)polymer, an acrylamide(co)polymer, an acryloylmorpholine(co)polymer, an N-vinyl pyrrolidone(co)polymer, a vinyl amine(co)polymer, an N,N-dimethyldiallyl ammonium chloride(co)polymer, 2-methacryloyloxy methyl ammonium chloride(co)polymer, a polyethylene glycol methacrylate(co)polymer, polyethyleneimine, and the like are exemplified.

The weight average molecular weight of the above hydrophilic polymers is preferably from 1,000 to 500,000, and more preferably from 5,000 to 100,000 from the viewpoint of moisture-retaining property. Further, the content of the hydrophilic polymers is preferably from 0.05 to 5% by mass and more preferably from 0.1 to 3% by mass in the hydrogel, from the viewpoint of the moisture-retaining property and handling characteristics.

[0114] Various kinds of active ingredients and additives in accordance with the intended use can also be blended into the high syneresis gel sheet. As such active ingredients and additives, for example, in addition to medical properties aiming at the beauty and facial treatments and the skin therapies, a moisturizer, a thickening agent, a fragrance, a colorant, a stabilizer, an antioxidant, an ultraviolet absorber, an adhesive-imparting agent, a pH adjuster, a chelating agent, a surfactant, an antiseptic, an antimicrobial, and the like are exemplified. Regarding these items, the foregoing descriptions can be applicable without modification. [0115] < Sheet-like Substrate >

In the high syneresis gel sheet, for the purpose of reinforcing the hydrogel layer and improving the handling characteristics of the gel sheet, a sheet-like substrate may be provided in the hydrogel layer or adjacent to the hydrogel gel layer. The sheet-like substrate is preferably provided in view of an improvement of the shape stability and handling characteristics of the high syneresis gel sheet.

[0116] In the high syneresis gel sheet, when a sheet-like substrate is used as a support layer, known sheet-like substrate materials such as nonwoven fabrics, textile fabrics and plastic films can be used.

Materials for forming nonwoven fabrics or textile fabrics are not specifically limited, and fibers generally used are usable, and natural fibers such as cellulose, fibroin and the like, recycled fibers such as rayon and the like, synthetic fibers such as nylon, polyester, polyethylene, polypropylene, acrylic resin, polylactic acid, polyurethane and the like are exemplified, and cellulose, nylon and polyester can suitably be used.

[0117] The textile fabrics or nonwoven fabrics suitably used for a high syneresis gel sheet has a basis weight preferably in the range of from 3g/m² to 100g/m², more preferably from

5g/m² to 70g/m², and particularly from 5g/m² to 50g/m². In this range of the basis weight, a sheet-like substrate has a strength with superior handling characteristics, and at the same time, the flexibility of the gel sheet is not deteriorated and the adhesiveness of the gel sheet at the time of adhesion is not reduced.

[0118] When a plastic film is used, the plastic film may be either a liquid impermeable single layer or a multiple-layered plastic sheet, or may be a porous sheet or mesh sheet.

The thickness of the sheet-like substrate is preferably approximately from 0.01mm to lmm from the viewpoint of the handling characteristics. Further, when used for cosmetic material or the like, a sheet with a high transparency may be preferable as described in this specification.

[0119] When the sheet-like substrate is used in a hydrogel layer, a liquid permeable sheet, for example, textile fabrics, nonwoven fabrics, porous sheet, mesh sheet and the like are preferable, but, when used as a support on one surface of the hydrogel layer, a liquid impermeable sheet or thick textile fabrics, nonwoven fabrics and the like can be used. [0120] Further, when the sheet-like substrate is used as a reinforcing layer for the hydrogel layer, a substrate such as a polymer gel sheet with a high breakage strength and a hydrophilic polymer film such as a crosslinked gel (gelatin/glutaraldehyde crosslinked gel, polyacrylic acid/polyvalent metal ion crosslinked gel, and the like), and a physical gel (agarose gel, κ-carrageenan gel, and the like), and as well as a water-insoluble film formed from a hydrophilic polymer (chitosan film, cellophane, κ-carragheenan cast film, and the like) and the like can be used. [0121] Among them, the high syneresis gel sheet having a structure integrally formed from the hydrogel and textile fabrics or nonwoven fabrics is particularly desirable. Here, the integrally formed structure refers to a structure in which a substrate sheet such as textile fabrics, nonwoven fabrics and the like is laminated on at least one surface of the hydrogel layer, and the substrate sheet and the hydrogel layer are adhered to each other so as not to be separated from each other during handling, or a structure in which the substrate sheet is included in the hydrogel layer integrally and indivisibly, and the hydrogel layers are disposed on the both surfaces of the substrate sheet

[0122] The high syneresis gel sheet is preferably provided with a protective sheet on the surface of the gel sheet to be applied to a living body, for the purpose of maintaining active ingredients or water retentivity until the use of the gel sheet.

As the protective sheet, a polyethylene film, a polypropylene film, a PET film and the like are preferably used. In particular, a polyethylene film with a thickness of 500μm or less, and more preferably from 20μm to 400μm is preferably used. [0123] The thickness of the hydrogel layer in the high syneresis gel sheet is preferably from 0.4mm to 2mm, and particularly preferably from 0.5mm to 1.5mm, generally regardless of the presence of a support, from the viewpoint of the form retentivity and handling characteristics. [0124] [Production Method of Gel Sheet]

The gel sheet of the invention can be produced in accordance with the methods commonly used.

For example, when a gel sheet is formed of only a hydrogel, the gel sheet can be manufactured in accordance with the usual method of manufacturing a hydrogel, more specifically, and after a mixed liquid (blended liquid for forming hydrogel) is prepared by heating and mixing components, a gel sheet is formed by means of a coating machine such as a doctor blade and the like. Subsequently, the gel sheet is cooled to accomplish gelation, thereby obtaining the gel sheet.

[0125] In the case of a gel sheet having a support layer, the gel sheet can easily obtained, for example, by laminating by coating a mixed aqueous solution of components for a hydrogel as described in the above on a sheet-like support substrate.

[0126] Further, the polyhydric alcohol, the O/W type emulsion and the polysaccharide may be added in the process of manufacturing the hydrogel, separately or together with one another, or after the manufacture of the hydrogel separately or together with one another.

[0127] Furthermore, when a protective sheet is formed, in the case of a gel sheet formed from only the hydrogel layer, one surface or both surfaces of the gel sheet may be covered with the protective sheet and in the case of a laminated structure formed of the sheet-like substrate and the hydrogel layer, the protective layer is laminated on the surface, where the sheet-like substrate is not formed, of the gel layer.

[0128] [Physical Properties of Gel Sheet]

A high transparency of the gel sheet of the invention is preferable in view of relieving seemingly uncomfortable feeling at the time of adhering the gel sheet onto the skin.

Further, when the gel sheet is required to have a high transparency, it is desirable to select the sheet-like substrate or the like, which is used together with the hydrogel layer, having a high light transmittance such as a nylon mesh, a transparent resin film. [0129] The transparency in the invention can be evaluated on the basis of values evaluated from the transmittance in the wavelength of 600nm with a spectrophotometer. The above transparency is desirable a transparency such that the transmittance with reference to distilled water measured by the evaluation method is preferably 60% or more, and more preferably 98% or more.

[0130] When the transmittance is 60% or more, it becomes feasible to check the state of the skin at the time of adhesion. However, in the case of adhering the gel sheet onto a body site where seeming is unconcerned, the gel sheet is not necessarily transparent. [0131] The water content of the hydrogel in the gel sheet of the invention is desirably 70% by mass or more, and 95 % by mass or less. When the water content is in this range, the releasing efficiency of the active ingredients from the hydrogel is not only improved, but can reduce the irritant property to the epidermis at the time of adhering the gel sheet. [0132] The water content of the hydrogel is preferably 70% by mass or more and 95% by mass or less, more preferably 75% by mass or more and 95% by mass or less, and particularly preferably 80% by mass or more and 90% by mass or less. When the water content is less than 70% by mass, the skin permeability of ingredients may decrease, and when the water content exceeds 95% by mass, the handling characteristics may deteriorate due to decrease in the strength of the hydrogel.

[0133] In particular, in the case of the above syneresis gel sheet, since the syneresis is excellent, such active ingredients can be efficiently permeated into a predetermined target site of the adherend, for example, a living body and the like by containing various active ingredients in the hydrogel in the range of the preferred water content. Accordingly, the gel sheet of the invention can be suitably used as a sustained-release carrier for the active ingredients or cosmetic materials.

[0134] More specifically, Ig of a hydrogel taken out from a gel sheet, is dried at 25°C under reduced pressure until a mass change of the sample is not observed, and the above water content is given by the value calculated based on the formula (2) as shown below:

Water content (%) =

[(initial mass - mass after drying)/initial mass] x 100 (2)

[0135] The water content of the hydrogel can be measured from the reduction rate of the mass of the hydrogel due to heat drying or reduced pressure drying. Alternatively, the water content of the hydrogel can be measured with a Carl Fischer type, an infrared ray type, or an electric resistance type aquameter. Further, when a hydrogel blended liquid itself gels, the blending ratio of water may be regarded as the water content of a gel. [0136] Although the form of the gel sheet of the invention is not specifically restricted, the form may be a roll shape formed by winding a tape, or may be an independently separate sheet piece by piece. In the case of an individual sheet, the form is arbitrary and is suitably selected in accordance with the intended use and the body site, for example, an ellipse form, a circular form, a heart form, a semicircle form, a semiellipse form, a square form, a rectangular form, a trapezoidal form, a triangular form, or a combination form thereof, and the like are exemplified, and further, a shape along the pattern of the body site to be applied, or the shape, by which the gel sheet can be most suitably adhered to a body site to be used, may be appropriately designed.

[0137] For example, when the gel sheet is used as an adhesive sheet for a living body, an embodiment can be assumed such that a convex portion or a concave portion is formed at a central potion or a peripheral portion of the gel sheet for the purpose of positioning the gel sheet or the like, or a cutoff portion or a cutout portion is formed in accordance with the shape of the body site to be applied, so that the embodiment enables the adhesive sheet to increase in handling characteristics, and to enhance the adhesiveness with an adherend contacting with the sheet in a required domain. [0138] The body sites of a living body to which the gel sheet of the invention is applied include the face (the lip, gena, eye area, above or under part of eyes, nasal part, forehead, or entire face), the arm part, leg part, chest part, abdomen part, neck part, cephalic part and the like.

When the gel sheet of the invention is used as an adhesive sheet for a living body, not only the above-described form, but the area, thickness, adhesiveness of the uppermost surface of the hydrogel layer, and the like are appropriately adjusted according to the body sites. Furthermore, the kind and content of active ingredients to be incorporated into the gel sheet can also suitably be adjusted.

[0139] For example, when an adhesive sheet for a living body for the entire face as a body site, to which the adhesive sheet is applied, is formed, it is preferable to make adjustments such that the shape in which the portions corresponding to the positions of the eyes and mouth are cut out, and the portion corresponding to the position of the nasal part is cut off, and further, the adhesiveness of the adhesive layer is increased or the thickness of the gel sheet is reduced suitable for a larger area to be adhered. Moreover, the form of the adhesive sheet for the face may be divided into two such that an upper part for the forehead, eyes and nasal peripheral part, and the lower part for the oral peripheral part and jaw part are formed.

[0140] These gel sheets may be sealed before use in a packaging material made of a gas impermeable material in order to prevent water content and active ingredients from decreasing with time.

For example, in the case of the gel sheet in a continuous tape shape, the gel sheet can be stored in an airtight container, for example, the packing bag formed from a gas impermeable sheet with a zipper, or a container formed from a gas impermeable resin with an openable and closable lid. Moreover, in the case of independently separate sheets piece by piece, the individual sheet may be sealed within an openable individual bag formed from a gas impermeable sheet. Water content and active ingredients can be maintained in a suitable state during storage and distribution until the use of the gel sheet. [0141] The gel sheet of the invention constituted as described above has an excellent permeability of active ingredients and the like into an adherend and excellent handling characteristics, and is useful for adhesive agents as carriers for percutaneous absorptive medical supplies for administrating drugs to a living body, sheet-like cosmetic materials such as packs used for beauty and facial treatments and skin therapies, carriers for active ingredients such as skin permeable components, antiphlogistic analgetics, adhesive tapes for a living body aimed at the protection against wound or the fixation of drug, and an injury-covering agent, by selecting the kind or amount of ingredients to be contained in the hydrogel layer, the thickness of the hydrogel layer, and the dosage form of the gel sheet. [0142] Since the high syneresis gel sheet excels in the adhesiveness to living bodies, moisture-retaining property and the syneresis of active ingredients, and exhibits good handling characteristics, water or active ingredients can be particularly efficiently supplied to an adherend at the time of adhesion, so that the high syneresis gel sheet is suitably used for all uses necessary for continuously supplying water or active ingredients, and excels in biocompatibility and safety, so that in the use of supplying water or active ingredients by applying the gel sheet to living bodies, the effect is remarkable, and can suitably be used as a sustained-release carrier for active ingredients, and cosmetic materials. [0143] [Sheet-like Cosmetic Material]

The sheet-like cosmetic material of the invention can comprise the gel sheet of the invention. That is, as an active ingredient, a moisturzing ingredient, a skin-whitening ingredient, an astringent ingredient, and the like are held by the gel sheet of the invention to form a cosmetic material. This sheet-like cosmetic material is used by bringing the surface of the hydrogel layer into contact with the skin.

[0144] Since the adhesive gel sheet for living bodies of the invention is excellent in the permeability of the active ingredients and the like to the skin, and the handling characteristics, the sheet-like cosmetic material of the invention is particularly useful as a sheet-like cosmetic material for moisturizing the skin or providing the skin with medical properties by adhering the material to the face.

[EXAMPLES]

[0145] Hereafter, the invention will be further described in detail with reference to the following examples, but the invention is not limited to the examples. In addition, unless it otherwise specified, "part" and "%" refer to "part by mass" and "% by mass", respectively.

[0146] [Example 1]

The following components were stirred upon heating at 50°C for one hour to obtain a sol-state solution 1.

^• Acid processed gelatin (derived from pig skin origin) 3.0g

^• 1,3-butanediol 5.0g . PLURONIC F- 127

(PEO-PPO-PEO block polymer: manufactured by BASF A.G.) 0.5g

^• Pure water 41.5g

[0147] The sol solution 1 was subjected to a casting to form a thickness of lmm in a case made from polystyrene with a size of 65mm x 95mm, and cooled at 4⁰C for 16 hours to obtain a hydrogel for Example 1. The hydrogel was referred to as the gel sheet of Example 1. The transmittance of the gel sheet at the wavelength of 600nm by use of a spectrophotometer was 85%. [0148] [Example 2]

A hydrogel of Example 2 was obtained by a method similar to the manufacturing process of the hydrogel of Example 1 except that PLURONIC F- 127 was replaced with polymethyl vinylether, and the hydrogel of Example 2 was referred to as the gel sheet of Example 2. The transmittance of the gel sheet at the wavelength of 600nm by use of a spectrophotometer was 72%. [0149] [Example 3]

A hydrogel of Example 3 was obtained by a method similar to the manufacturing process of the hydrogel of Example 1 except that PLURONIC F- 127 was replaced with methylcellulose, and the hydrogel of Example 3 was referred to as the gel sheet of Example 3. The transmittance of the gel sheet at the wavelength of 600nm by use of a spectrophotometer was 84%. [0150] [Example 4]

< Preparation of Carotenoid-Containing Emulsion >

The following components were dissolved upon heating at 7O⁰C for one hour, and a water-phase composition was obtained.

^• Sucrose oleate 13g

^• Monooleic acid decaglyceryl 25g

^• Glycerin 50Og

^• Pure water 322g [0151] The following components were dissolved upon heating at 70°C for one hour and an oil-phase composition was obtained.

^• Haematococcus Pluvialis extract (astaxanthins content 20 % by mass) 4Og

^• Mix Tocopherol 1Og

^• Lecithin (derived from soybean) 9Og [0152] The above oil-phase composition was added to the water-phase composition with stirring by means of a homogenizer (10,000rpm), while maintaining at 70°C, and a carotenoid-containing emulsion was obtained. The resultant carotenoid-containing emulsion was subjected to a high-pressure emulsification at a pressure of 200MPa using ULTIMIZER HJP-25005 (manufactured by Sugino Machine Limited). The volume average particle diameter of the obtained emulsion was measured by a thickened system particle size analyzer FPAR-1000 (Otsuka Electronics Co., Ltd.) at 25°C and the volume average particle diameter of 90nm was obtained.

[0153] < Preparation of Hydrogel >

The following components were heated and kneaded at 80°C, and a sol-state product 2 was obtained.

^• K-carragheenan 0.2g

^• Gulcomannan (derived from elephant root) 0.2g

^• Acid processed gelatin (derived from pig skin) 0.5g

^• PLURONIC F- 127 -

(PEO-PPO-PEO block polymer: manufactured by BASF A.G.) 0.5g

^• 1,3-butanediol 5.Og

^• Pure water 43.1g [0154] After the sol-state product 2 was cooled to 60°C, 0.5g of the carotenoid-containing emulsion was added thereto, and the mixture was uniformly stirred to obtain a solution. The solution was subjected to a casting to form a thickness of lmm in a case made from polystyrene with a size of 65mm x 95mm, and cooled at 4°C for 16 hours to obtain a hydrogel for Example 4. The hydrogel was referred to as the gel sheet of Example 4. The transmittance of the gel sheet at the wavelength of 600nm by use of a spectrophotometer was 80%. [0155] [Comparative Example 1]

The following components was stirred upon heating at 50°C for one hour, and a sol-state solution 3 was obtained.

^• Acid processed gelatin (derived from pig skin) 3.0g

^• 1,3-butanediol 5.0g

^• Pure water 42.Og [0156] The sol-state solution 3 was subjected to a casting to form a thickness of lmm in a case made from polystyrene with a size of 65mm x 95mm, and cooled at 4°C for 16 hours to obtain a hydrogel. The hydrogel was referred to as the gel sheet of Comparative Example 1.

[0157] [Comparative Example 2]

The following components were heated and kneaded at 80°C, and a sol-state product 4 was obtained.

^• K-carragheenan 0.2g

^• Gulcomannan (derived from elephant root) 0.2g

^• PLURONIC F- 127

(PEO-PPO-PEO block polymer: manufactured by BASF A.G.) 0.5g

^• 1,3-butanediol 5.Og ^• Pure water 44.1g

[0158] The sol-state solution 4 was subjected to a casting to form a thickness of lmm in a case made from polystyrene with a size of 65mm x 95mm, and cooled at 4⁰C for 16 hours to obtain a hydrogel. The hydrogel was referred to as the gel sheet of Comparative Example 2. [0159] [Comparative Example 3]

Polyethyleneglycol-copolybutylene naphthalate was dissolved in THF so as to become a concentration of 10% by mass. The solution was subjected to a casting on a tray made of TEFLON (registered trademark) with a size of 5 cm x 5 cm, and died at ordinary temperature and pressure to form a film. The film was immersed into 100ml of pure water, and a hydrogel was obtained. The hydrogel was referred to as the gel sheet of Comparative Example 3. [0160] [Comparative Example 4]

A hydrogel was obtained by a method similar to the manufacturing process of the hydrogel of Example 1 except that PLURONIC F- 127 was replaced with poly (N-isopropylacrylamide). The hydrogel was referred to as the gel sheet of Comparative Example 4.

[0161] - Evaluation of Gel Sheet -

The gel sheets of Examples 1 to 4 and Comparative Example 1 to 4 were actually used by graders such that the gel sheet was adhered onto the face for each grader (gel sheet was adhered onto eye area of each grader for fifteen minutes after face wash), evaluations were conducted in accordance with the following methods and criteria, and the evaluation results are shown in Table 1 below. The evaluation results are shown as the mean values of the evaluation results by five graders. [0162] (l) Operability

Evaluations were conducted in such a manner that in the case that when the gel sheet was adhered onto the face, the gel sheet was easily adhered without being stuck on the graders' fingers, the gel sheet was rated at A; in the case that it took a time for adhering due to sticking of the sheet on the graders' fingers, the gel sheet was rated at B; and in the case that when the gel sheet was easily broken and adhering was difficult, the gel sheet was rated at C. [0163] (2) Sense of Adhesion

In the operations of the above "(1) operability", the sense of adhesion was evaluated in such a manner that, in the case that when the gel sheet adhered onto the face came into close contact with the face along the surface thereof, the gel sheet was rated at A; when the gel sheet came off in part; the gel sheet was rated at B; and when the gel sheet got wrinkles, and a number of portions of the gel sheet were exfoliated, the gel sheet was rated at C. [0164] (3) Moisture-Retaining Property

The gel sheet was stuck for 15 minutes, and after the gel sheet was exfoliated, the amount of the water content in the keratin layer after a lapse of 30 minutes was measured with a keratin layer aquameter (manufactured by Asahibiomed). The moisture-retaining property was evaluated in such as manner that in the case that when an increase in the water content was 10% or more at the mean value of the evaluated values by the five graders, the gel sheet was rated at A; in the case that when an increase in the water content was from 2 % to 10%, the gel sheet was rated at B; and in the case that when an increase in the water content was less than 2 %, the gel sheet was rated at C. [0165] (4) Skin Barrier Property In order to evaluate an improvement function of rough dry skin, the transepidermal water loss (TEWL) was measured by the following methods.

That is, a gel sheet was adhered periodically for 15 minutes a day for three consecutive days, and the transepidermal water loss (TEWL) immediately after exfoliation of the gel sheet on the third day was measured by a transepidermal water loss meter (manufactured by Asahibiomed). The skin barrier property was evaluated in such a manner that in the case that when the TEWL value dropped to 5% or more as compared with the value before the test, the gel sheet was rated at A; in the case that when the drop was from 1 to 4%, the gel sheet was rated at B; and in the case that when the TEWL value was not changed, the gel sheet was rated at C.

[0166] Table 1

[0167] As shown in Table 1, it is clear that all the gel sheets in Examples 1 - 4 are excellent in the operability, tight fit feeling, moisture-retaining property and skin barrier property. Accordingly, it is clear that the gel sheets having such as excellent effects are also excellent as sheet-like cosmetic materials. [0168] Example 5

< Preparation of O/W Type Emulsion >

^• Sucrose oleate 15g

^• Monooleic acid decaglyceryl 23g

^• Glycerin 500g

^• Pure water 322g

Further, the following components were dissolved upon heating at 70°C for one hour and an oil-phase composition was obtained.

^• Haematococcus Pluvialis extract (astaxanthins content 20 % by mass) 4Og

^• Mix Tocopherol 1Og

^• Lecithin (derived from soybean) 9Og [0169] The above water-phase composition was added to the oil-phase composition with stirring by means of a homogenizer (10,000rpm), while maintaining at 70°C, and an emulsion was obtained. The resultant emulsion was subjected to a high-pressure emulsification at a pressure of 200MPa using ULTIMIZER HJP-25005 (manufactured by Sugino Machine Limited). The volume average particle diameter of the obtained emulsion was measured by a thickened system particle size analyzer FPAR-1000 (Otsuka Electronics Co., Ltd.) at 25⁰C and the volume average particle diameter of 90nm was obtained.

[0170] < Preparation of Hydrogel > The components except for the emulsion among the components described in Table 2 were successively added to water, and heated and kneaded at 80°C, to obtain a sol-state product.

After cooling this sol product to 60⁰C, the above O/W type emulsion was added to the sol product, and stirred uniformly. After extending the resultant hydrogel using a doctor blade so as to form a thickness of 0.8mm, the hydrogel was covered with a mesh nylon fabric with a basis weight of 20g/m² and allowed to stand at 25 °C for 30 minutes so that the gel sheet of Example 5 having the nylon mesh sheet as the sheet-like substrate with hydrogel layers on both surfaces of the substrate was obtained. The total thickness of the hydrogel layers was 0.8mm.

In addition, the numerical values showing amounts of components in Table 2 are expressed in terms of parts by mass. [0171] [Example 6 - 8 and Comparative Examples 5 - 8]

As shown in Table 2, each component was used in a manner similar to Example 5, adhesive gel sheets for living bodies according to Examples 5 - 8, and Comparative Examples 5 - 8 were obtained. [0172] (Evaluation of Adhesive Gel Sheet for Living Body)

Using the adhesive gel sheet for living bodies of Examples 5 - 8, and Comparative Examples 5 - 8, the following evaluations were performed and the evaluation results are shown in Table 2 below. In addition, each functional evaluation of the adhesiveness, moisture-retaining property, skin barrier property, and effect for making the skin beautiful was made by ten graders (adhered onto the face) using the gel sheets of Examples 5 - 8, and Comparative Examples 5 - 8, and the mean values of the evaluation results are shown in Table 2. [0173] (1) Syneresis Rate

The adhesive gel sheets for living bodies of Examples 5 - 8, and Comparative Examples 5 - 8 were cut into a size of 3cm x 3cm to form sample gel sheets, and these sample gel sheets were interposed between No.2 filter paper manufactured by Advantec MSF. Inc., so as to be two sheets of the filter paper for each of the upper and lower sides of the sample gel sheets, and the change of the mass of the filter paper was measured when allowing to stand under the circumstances of 25°C and the relative humidity of 55% for 10 minutes. The syneresis rate was calculated by the formula shown below using the obtained measured values. The test was reiterated five times and the mean values thereof are shown in Table 2.

Syneresis rate (% by mass) -

(mass of absorbed liquid by filter paper/initial mass of gel) x 100

Here, the "initial mass of gel" was obtained by subtracting the mass of the nylon mesh as the sheet substrate from the mass of the sample gel sheet test piece. [0174] (2) Coloration of Syneresis Liquid

The coloration degree of the liquid-absorbed filter paper was estimated in the evaluation of the syneresis rate.

When coloration originated from carotenoids was clearly observed, the sample was rated at A, when slight coloration was observed, the sample was rated at B, and when coloration was not visually distinctive, the sample was rated at C. [0175] (3) Content Ratio of Emulsion in Syneresis Liquid

Astaxanthin contained in the filter paper was extracted in such a manner that 5 parts by mass of water and 4 parts of acetone were added to one part of absorbed liquid in the liquid absorbed filter paper in the evaluations of the syneresis rate. For comparison, 5 parts by mass of water and 4 parts of acetone were added to one part of the blended liquid for forming hydrogel, and the absorbance at 473nm of the resultant extraction liquid was measured by a spectrophotometer (V-630: manufactured by JASCO Corporation), and the content ratio of emulsion in the syneresis liquid was calculated according to the following formula:

Content ratio of emulsion in syneresis liquid =

Absorbance at 473nm of syneresis liquid extraction liquid/

Absorbance at 473nm of blended liquid for forming hydrogel [0176] (4) Water Content

One gram of each hydrogel layer taken out from the gel sheets in Examples 5 - 8 and Comparative Examples 5 - 8 was dried at 25⁰C under reduced pressure. The drying was continued until the mass change of the sample was not observed, and the water content was calculated according to the following formula:

Water content (%) =

[(initial mass - mass after drying) / initial mass] x 100

The above measuring test was reiterated five times and the mean values thereof were rated at the water content. [0177] (5) Sense of Adhesion

The sense of adhesion was evaluated in such a manner that when the gel sheet adhered onto the face came into close contact with the face along the surface thereof, the gel sheet was rated at A; when the gel sheet came off in part; the gel sheet was rated at B; and when the gel sheet got wrinkles, and a number of portions of the gel sheet were exfoliated, the gel sheet was rated at C. [0178] (6) Moisture-Retaining Property Before the gel sheet was adhered, the water content of the keratin layer at the eye area in the face for ten graders was measured with a keratin layer aquameter (manufactured by Asahibiomed), and evaluated in terms of conductance value. Thereafter, the gel sheet was stuck for 15 minutes, and after the gel sheet was peeled off, the amount of the water content in the keratin layer after a lapse of 30 minutes was measured with a keratin layer aquameter (manufactured by Asahibiomed) as the value of the conductance. Comparison between the values before adhering and after adhering was made for ten graders, and when an increase in the mean value of conductance was 10% or more, the gel sheet was rated at AA, when an increase from 2% to 10% was observed, the gel sheet was rated at B, and when an increase was less than 2%, the gel sheet was rated at C. [0179] (7) Skin Barrier Property

In order to evaluate an improvement function of rough dry skin, the transepidermal water loss (TEWL) was measured by the following methods.

That is, a gel sheet was adhered periodically for 15 minutes a day for three consecutive days, and the transepidermal water loss (TEWL) immediately after exfoliation of the gel sheet on the third day was measured by a transepidermal water loss meter (manufactured by Asahibiomed). The skin barrier property was evaluated in such a manner that when the TEWL value dropped to 5% or more as compared with the value before the test, the gel sheet was rated at A; when the drop was from 1 to 4%, the gel sheet was In order to evaluate an improvement function of rough dry skin, the transepidermal water loss (TEWL) was measured by the following methods. [0180] That is, a gel sheet was adhered periodically for 15 minutes a day for three consecutive days, and the transepidermal water loss (TEWL) immediately after peeling off the gel sheet on the third day was measured by a transepidermal water loss meter (manufactured by Asahibiomed). The skin barrier property was evaluated in such a manner that in the case that when the TEWL value dropped to 5% or more as compared with the value before the test, the gel sheet was rated at A; when the drop was from 1 to 4%, the gel sheet was rated at B; and when the change of the TEWL value was not observed, the gel sheet was rated at C. [0181] (8) Functional Evaluation

When a gel sheet was adhered periodically for 15 minutes a day for three consecutive days, and the impression of the appearance of the skin immediately after peeling off the adhesive gel sheet for living bodies on the third day was evaluated. When a clear feeling of improvement of the skin texture was obtained, the gel sheet was rated at A; when subtle feeling of improvement of the skin texture was obtained, the gel sheet was rated at B, and when improvement of the skin texture was not felt, the gel sheet was rated at C.

[0182]

Table 2

n.d. : Not detected [0183] From the results of Table 2, it is clear that the syneresis rate of the adhesive gel sheets for living bodies in Examples 5 - 8 is high, and the O/W type emulsion particles are contained in the syneresis liquid. Moreover, it becomes clear that the improvement effect of the moisture-retaining property, skin barrier property and skin texture are excellent.

On the other hand, with the adhesive gel sheets for living bodies in the Comparative Examples 5 - 8, the quantities of the syneresis liquid are small, and the emulsion is not contained in the syneresis liquid, actual feelings of improvements particularly in the functional evaluations cannot obtained, and moisturizing effect is also insufficient.

[0184] The disclosure of Japanese Patent Applications No. 2007-244489 is incorporated by reference herein.

All publications, patent applications, and technical standards mentioned in this specification are herein incorporated by reference to the same extent as if such individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference. It will be obvious to those having skill in the art that many changes may be made in the above-described details of the preferred embodiments of the present invention. The scope of the invention, therefore, should be determined by the following claims.

Claims

1. A gel sheet comprising a hydrogel which comprises an ether-based temperature-sensitive polymer, and at least one of collagen or decomposition products of collagen.

2. The gel sheet according to claim 1, wherein the ether-based temperature-sensitive polymer is at least one selected from the group consisting of polyethers, polyvinyl ethers, and alkylated polysaccharide derivatives.

3. The gel sheet according to claim 2, wherein the one of the polyethers, polyvinyl ethers, and alkylated polysaccharide derivatives has at least one functional group selected from the group consisting of an oxyethylene group, an oxypropylene group, a methoxy group, and an ethoxy group.

4. The gel sheet according to any of claims 1-3, wherein the ether-based polymer is a block polymer containing polyethylene oxide and polypropylene oxide.

5. The gel sheet according to any of claims 1-4, wherein the gel sheet further comprises an O/W type emulsion.

6. The gel sheet according to claim 5, wherein the O/W type emulsion comprises a carotenoid.

7. The gel sheet according to claim 5 or claim 6, wherein the average particle diameter of the emulsified particles of the O/W type emulsion is l-150nm.

8. The gel sheet according to any of claims 5-7, wherein the emulsified particles of the OAV type emulsion are included in a syneresis liquid of the gel sheet.

9. The gel sheet according to any of claims 1-8, wherein the gel sheet comprises a hydrogel formed by using an anionic polymer compound and water-soluble divalent metal salt.

10. The gel sheet according to any of claims 1-9, wherein the gel sheet further comprises a polysaccharide.

11. The gel sheet according to any of claims 1-10, wherein the gel sheet further comprises a polyhydric alcohol compound.

12. The gel sheet according to any of claims 1-11, wherein the water content of the gel sheet is from 70% by mass to 95% by mass.

13. The gel sheet according to any of claims 1-12, wherein the gel sheet comprises a hydrogel layer containing the hydrogel and a sheet-like substrate provided in the hydrogel layer or adjacent to the hydrogel gel layer.

14. The gel sheet according to any of claims 1-13, wherein the thickness of the gel sheet is from 0.4mm to 2mm.

15. A sheet-like cosmetic material using any one of the gel sheets according to claims 1-14.