Polymer gel

Abstract

To provide a polymer gel releasing an active ingredient in response to a part of a body, a body temperature, or a stimulus such as heat or light without applying external force or with only assistance of slight external force.SOLUTION: A polymer gel includes a first stimulus-responsive polymer gel containing a first stimulus-responsive polymer that exhibits hydrophobicity in a state where a degree of external stimulus is less than a first level and exhibits hydrophilicity in a state where the degree of the external stimulus is equal to or greater than the first level, and a second stimulus-responsive polymer gel containing a second stimulus-responsive polymer that exhibits hydrophilicity in a state where the degree of the external stimulus is less than a second level and exhibits hydrophobicity in a state where the degree of the external stimulus is equal to or greater than the second level.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] One aspect of the present invention relates to an application member that can be impregnated with an active ingredient and an impregnated material impregnated with the active ingredient. This application claims priority to Japanese Patent Application No. 2019-177956, filed on September 27, 2019, the contents of which are incorporated herein by reference. [Background technology]

[0002] BACKGROUND ART As described in Patent Document 1, conventionally, products have been known in which an impregnating material such as a sponge is impregnated with a liquid ingredient in order to apply the liquid ingredient such as a lotion to the skin. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-292786 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the above-mentioned products, the impregnating material must be pressed or rubbed against the skin in order to cause the liquid component to seep out of the impregnating material, which can be a burden to sensitive skin.

[0005] One aspect of the present invention aims to release an active ingredient in response to a body part, body temperature, or a stimulus such as heat or light without applying an external force or with only a slight external force. [Means for solving the problem]

[0006] In order to solve the above problems, a polymer gel according to one embodiment of the present invention comprises a first stimuli-responsive polymer gel containing a first stimuli-responsive polymer that exhibits hydrophobicity when the level of an external stimulus is below a first level and hydrophilicity when the level of the external stimulus is equal to or higher than the first level, and a second stimuli-responsive polymer gel containing a second stimuli-responsive polymer that exhibits hydrophilicity when the level of the external stimulus is below a second level and hydrophobicity when the level of the external stimulus is equal to or higher than the second level. [Effects of the Invention]

[0007] According to one aspect of the present invention, an active ingredient can be released in response to a stimulus such as a body part, body temperature, heat, or light without applying an external force or with only a slight external force. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing the configuration of an impregnated material according to a first embodiment of the present invention. [Figure 2] FIG. 10 is a perspective view showing the configuration of an impregnated material according to a second embodiment of the present invention. [Figure 3] FIG. 10 is a perspective view showing the configuration of an impregnated material according to a third embodiment of the present invention. [Figure 4] FIG. 10(a) is a plan view showing the configuration of an impregnating material of a first modified example according to the third embodiment, and FIG. 10(b) is a perspective view showing the configuration of the impregnating material. [Figure 5] FIG. 10(a) is a plan view showing the configuration of an impregnating material of a second modified example according to the third embodiment, and FIG. 10(b) is a perspective view showing the configuration of the impregnating material. [Figure 6] FIG. 10 is a perspective view showing the configuration of an impregnating material of a third modified example according to the third embodiment. [Figure 7] FIG. 10 is a perspective view showing the configuration of an impregnating material of a fourth modified example according to the third embodiment. [Figure 8] FIG. 10 is a perspective view showing the configuration of an impregnated material according to a fourth embodiment of the present invention. [Figure 9] FIG. 10 is a perspective view showing the configuration of an impregnated material according to a fifth embodiment of the present invention. [Figure 10]FIG. 10 is a perspective view showing the configuration of an applicator member according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Stimulus-responsive polymer gel) Stimuli-responsive polymer gels contain stimuli-responsive polymers, whose affinity for water changes reversibly in response to external stimuli, and hydrophilic polymers. The stimuli-responsive polymers and hydrophilic polymers form an interpenetrating polymer network (IPN) structure, a semi-interpenetrating polymer network (semi-IPN) structure, a random network structure, or a block structure.

[0010] Here, an interpenetrating polymer network structure refers to a structure in which different types of polymers, all of which are crosslinked polymers, are entangled with each other in a state in which the crosslinked networks of each polymer exist independently without being chemically bonded, and a semi-interpenetrating polymer network structure refers to a structure in which different types of polymers, one of which is a crosslinked polymer and the other is a linear polymer, are entangled with each other in a state in which the crosslinked networks of each polymer exist independently without being chemically bonded.

[0011] In the former case, both the stimuli-responsive polymer and the hydrophilic polymer are crosslinked polymers having crosslinked networks, in which the crosslinked networks of the stimuli-responsive polymer and the crosslinked networks of the hydrophilic polymer are intertwined without chemical bonding, i.e., form an interpenetrating polymer network structure.

[0012] In the latter case, either the stimuli-responsive polymer or the hydrophilic polymer is a crosslinked polymer having a crosslinked network, and the other is a linear polymer, and the stimuli-responsive polymer and the hydrophilic polymer are entangled with each other without chemical bonding, i.e., form a semi-interpenetrating polymer network structure.

[0013] Alternatively, the stimuli-responsive polymer gel may be a copolymer having a random network structure or a block network structure of a stimuli-responsive polymer and a hydrophilic polymer. Furthermore, the stimuli-responsive polymer gel may be a copolymer of a single stimuli-responsive polymer or multiple stimuli-responsive polymers.

[0014] (Stimulus-responsive polymers) A stimuli-responsive polymer is a polymer that reversibly changes its properties in response to an external stimulus. In this embodiment, a stimuli-responsive polymer that reversibly changes its affinity for water in response to an external stimulus is used.

[0015] The external stimulus is not particularly limited, but examples thereof include heat, light, an electric field, and pH.

[0016] Furthermore, the phrase "the affinity for water changes reversibly in response to the level of an external stimulus" means that the polymer exposed to the external stimulus reversibly changes between hydrophilicity and hydrophobicity in response to the external stimulus.

[0017] Among them, stimuli-responsive polymers, whose affinity for water changes reversibly in response to heat, i.e., temperature-responsive polymers, reversibly absorb and release water in response to a change in temperature. Such temperature-responsive polymers are not particularly limited as long as they have a lower critical solution temperature (LCST, sometimes referred to as "LCST" in the following description).

[0018] (Temperature-responsive polymer) Thermoresponsive polymers exhibit hydrophilicity at temperatures below a certain level, i.e., the LCST, but exhibit hydrophobicity at temperatures above the LCST. Here, the LCST refers to the temperature at which, when a polymer is dissolved in water, it becomes hydrophilic and soluble in water at low temperatures, but becomes hydrophobic and insoluble above a certain temperature.

[0019] More specifically, examples of the temperature-responsive polymer include poly(N-alkyl(meth)acrylamides) such as poly(N-isopropyl(meth)acrylamide), poly(N-normal propyl(meth)acrylamide), poly(N-methyl(meth)acrylamide), poly(N-ethyl(meth)acrylamide), poly(N-normal butyl(meth)acrylamide), poly(N-isobutyl(meth)acrylamide), and poly(N-t-butyl(meth)acrylamide); poly(N-vinylisopropylamide), poly(N-vinylnormalpropylamide), poly(N-vinylnormalbutylamide), poly(N-vinylisobutylamide), and poly(N-vinyl-t-butylamide); Examples of suitable thermoresponsive polymers include poly(N-vinyl alkylamides); poly(N-vinylpyrrolidone); poly(2-alkyl-2-oxazolines) such as poly(2-ethyl-2-oxazoline), poly(2-isopropyl-2-oxazoline), and poly(2-normal-propyl-2-oxazoline); polyvinyl alkyl ethers such as polyvinyl methyl ether and polyvinyl ethyl ether; copolymers of polyethylene oxide and polypropylene oxide; poly(oxyethylene vinyl ether); cellulose derivatives such as methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, and hydroxyethyl cellulose, as well as copolymers of the above polymers. The temperature-responsive polymer is preferably a crosslinked polymer of these polymers. In particular, polysaccharide polymers such as the above-mentioned cellulose derivatives are preferred because they are less irritating and, as described below, can come into contact with human skin.

[0020] In this embodiment, as described above, the stimuli-responsive polymer and the hydrophilic polymer form an interpenetrating polymer network structure or a semi-interpenetrating polymer network structure. An example in which the stimuli-responsive polymer is a crosslinked polymer will be described below.

[0021] Examples of crosslinked temperature-responsive polymers include N-alkyl(meth)acrylamides such as N-isopropyl(meth)acrylamide, N-normal propyl(meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-normal butyl(meth)acrylamide, N-isobutyl(meth)acrylamide, and Nt-butyl(meth)acrylamide; N-vinyl alkylamides such as N-vinyl isopropylamide, N-vinyl normal propylamide, N-vinyl normal butylamide, N-vinyl isobutylamide, and N-vinyl-t-butylamide; vinyl alkyl ethers such as vinyl methyl ether and vinyl ethyl ether; ethylene oxide and propylene oxide; and 2-alkyl-2-oxazolines such as 2-ethyl-2-oxazoline, 2-isopropyl-2-oxazoline, and 2-normal propyl-2-oxazoline, or polymers obtained by polymerizing two or more of these monomers in the presence of a crosslinking agent.

[0022] The crosslinking agent may be selected from conventionally known agents. Suitable examples of such crosslinking agents include crosslinkable monomers having polymerizable functional groups, such as ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, N,N'-methylenebis(meth)acrylamide, tolylene diisocyanate, divinylbenzene, and polyethylene glycol di(meth)acrylate; glutaraldehyde; polyhydric alcohols; polyamines; polycarboxylic acids; metal ions, such as calcium ions and zinc ions; and calcium chloride. These crosslinking agents may be used alone or in combination of two or more.

[0023] Furthermore, the crosslinked thermoresponsive polymer may be a crosslinked polymer obtained by reacting an uncrosslinked thermoresponsive polymer, such as the above-mentioned thermoresponsive polymer, with the above-mentioned crosslinking agent to form a network structure.

[0024] Examples of stimuli-responsive polymers whose affinity for water changes reversibly in response to light include photoresponsive polymers such as azobenzene derivatives and spiropyran derivatives whose hydrophilicity or polarity changes in response to light, copolymers of these polymers with at least one of temperature-responsive polymers and pH-responsive polymers, crosslinked products of the photoresponsive polymers, and crosslinked products of the copolymers.

[0025] Furthermore, examples of stimuli-responsive polymers whose affinity for water changes reversibly in response to an electric field include polymers having dissociable groups such as carboxyl groups, sulfonic acid groups, phosphate groups, and amino groups; polymers that form complexes through electrostatic interactions or hydrogen bonds, such as complexes between carboxyl group-containing polymers and amino group-containing polymers; and crosslinked products of these.

[0026] Furthermore, examples of stimuli-responsive polymers whose affinity for water changes reversibly in response to pH include polymers having dissociable groups such as carboxyl groups, sulfonic acid groups, phosphate groups, and amino groups; polymers that form complexes through electrostatic interactions or hydrogen bonds, such as complexes between carboxyl group-containing polymers and amino group-containing polymers; and crosslinked products of these.

[0027] The molecular weight of the stimuli-responsive polymer is not particularly limited, but it is preferable that the number average molecular weight determined by gel permeation chromatography (GPC) is 3000 or more.

[0028] (hydrophilic polymer) In this embodiment, the hydrophilic polymer is not particularly limited as long as it is a hydrophilic polymer other than a stimuli-responsive polymer that forms an interpenetrating polymer network structure or a semi-interpenetrating polymer network structure together with the hydrophilic polymer.

[0029] Examples of the hydrophilic polymer include polymers having hydrophilic groups such as hydroxyl groups, carboxyl groups, sulfonic acid groups, phosphate groups, and amino groups on the side chains or main chains. More specific examples of hydrophilic polymers include polysaccharides such as alginic acid and hyaluronic acid; chitosan; cellulose derivatives such as carboxymethyl cellulose, methyl cellulose, ethyl cellulose, and hydroxyethyl cellulose; poly(meth)acrylic acid, polymaleic acid, polyvinyl sulfonic acid, polyvinylbenzene sulfonic acid, polyacrylamide alkyl sulfonic acid, polydimethylaminopropyl (meth)acrylamide, copolymers of these with (meth)acrylamide, hydroxyethyl (meth)acrylate, and (meth)acrylic acid alkyl esters, complexes of polydimethylaminopropyl (meth)acrylamide and polyvinyl alcohol, complexes of polyvinyl alcohol and poly(meth)acrylic acid, poly(meth)acrylonitrile, polyallylamine, polyvinyl alcohol, polyethylene glycol, polypropylene glycol, poly(meth)acrylamide, poly-N,N'-dimethyl(meth)acrylamide, poly-2-hydroxyethyl methacrylate, poly-alkyl (meth)acrylate, polydimethylaminopropyl (meth)acrylamide, poly(meth)acrylonitrile, and copolymers of the above polymers. Furthermore, the hydrophilic polymer is more preferably a crosslinked product of these.

[0030] In this embodiment, as described above, the stimuli-responsive polymer and the hydrophilic polymer form an interpenetrating polymer network structure or a semi-interpenetrating polymer network structure. An example in which the hydrophilic polymer is a crosslinked polymer will be described below.

[0031] Examples of crosslinked hydrophilic polymers include polymers obtained by polymerizing monomers such as (meth)acrylic acid, allylamine, vinyl acetate, (meth)acrylamide, N,N'-dimethyl(meth)acrylamide, 2-hydroxyethyl methacrylate, alkyl(meth)acrylate, maleic acid, vinylsulfonic acid, vinylbenzenesulfonic acid, acrylamidoalkylsulfonic acid, dimethylaminopropyl(meth)acrylamide, and (meth)acrylonitrile in the presence of a crosslinking agent.

[0032] The crosslinking agent may be selected from conventionally known agents as appropriate, and suitable examples include crosslinkable monomers having a polymerizable functional group such as ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, N,N'-methylenebis(meth)acrylamide, tolylene diisocyanate, divinylbenzene, and polyethylene glycol di(meth)acrylate; glutaraldehyde; polyhydric alcohols; polyvalent amines; polycarboxylic acids; metal ions such as calcium ions and zinc ions; calcium chloride; etc. These crosslinking agents may be used alone or in combination of two or more.

[0033] The crosslinked hydrophilic polymer may be a non-crosslinked hydrophilic polymer, for example, a polymer obtained by polymerizing the monomer, or a crosslinked polymer obtained by reacting a polysaccharide such as alginic acid or hyaluronic acid; chitosan; or a cellulose derivative such as carboxymethyl cellulose, methyl cellulose, ethyl cellulose, or hydroxyethyl cellulose with the above-mentioned crosslinking agent to form a network structure.

[0034] The molecular weight of the hydrophilic polymer is not particularly limited, but it is preferable that the number average molecular weight determined by GPC is 3000 or more.

[0035] (impregnating material) An impregnating material is made of a temperature-responsive polymer gel formed from the above-mentioned temperature-responsive polymer and hydrophilic polymer, and the impregnating material is impregnated with a solution containing an active ingredient, such as a beauty serum or a drug solution. The temperature-responsive polymer gel absorbs the solution when the temperature is below the LCST, but releases the solution when the temperature is above the LCST.

[0036] Active ingredients include cosmetic ingredients that are effective cosmetically and medicinal ingredients that are effective medically. Examples of cosmetic ingredients include moisturizing ingredients, UV protection ingredients, whitening ingredients, antioxidant ingredients, sebum control ingredients, and deodorizing ingredients. Examples of medicinal ingredients include anti-inflammatory ingredients, analgesic ingredients, blood circulation promoting ingredients, bactericidal ingredients, vitamins, steroids, and antibiotics.

[0037] To impregnate the impregnating material with the solution, the impregnating material is immersed in the solution. Alternatively, the solution may be sprayed onto the impregnating material from the viewpoint of easily adjusting the amount of solution impregnated. The solution may also be mixed into the impregnating material when it is prepared. In this case, the impregnating material will be in a dry state, but as will be described later, it will absorb moisture in the air and become moist, exhibiting the same behavior as when the material is impregnated with the solution.

[0038] Alternatively, the impregnating material may be in the first to third swollen gel states described below instead of a dried state, and exhibit the same behavior as when impregnated with a solution. The first gel state is obtained by drying a gel prepared from a mixture of the impregnating material material and a solution to allow it to absorb moisture. The second gel state is obtained by maintaining the prepared gel in a moist gel state without drying. The third gel state is a state in which a stimuli-responsive gel, i.e., an impregnating material, is prepared without mixing any active ingredient and then dried, and then impregnated with a cosmetic or medical active ingredient.

[0039] By simply applying heat to the impregnated material impregnated with the active ingredient as described above, the impregnated material absorbs moisture and becomes hydrophobic, releasing the active ingredient impregnated before or after preparation of the gel. For example, a temperature-responsive polymer gel with an LCST slightly lower than human body temperature of 37°C is used as the impregnating material. This allows the impregnated material to release a solution and deliver it to the skin when it comes into contact with human skin and its temperature rises above the LCST. This eliminates the need to press or rub the impregnated material against the skin to deliver the active ingredient to the skin.

[0040] The stimuli-responsive polymer gel used as the impregnating material is not limited to a temperature-responsive polymer gel, but may be a stimuli-responsive polymer gel that responds to stimuli such as light, an electric field, or pH. For example, when a photoresponsive polymer gel is used as the impregnating material, the impregnating material will be in a swollen state retaining the active ingredient when irradiated with light of an intensity less than a predetermined intensity (level) (similar to the intensity of normal indoor lighting), and will release the solution when irradiated with light of an intensity equal to or greater than the predetermined intensity. Furthermore, the photoresponsive polymer gel may be capable of reversibly changing between hydrophilic and hydrophobic properties depending on the wavelength of light.

[0041] Photoresponsive polymer gels themselves respond to light, but they may also contain a photothermal conversion substance (a photothermal converter such as carbon black or a conductive polymer) inside. Conductive polymers generate heat when exposed to light. Such photoresponsive polymer gels use a photothermal conversion substance to convert light into heat, and then have the thermosensitive polymer gel respond to that heat.

[0042] Hereinafter, embodiments of the impregnating material according to the present invention will be described in detail with reference to the drawings.

[0043] (Method of manufacturing impregnated material) The above-mentioned impregnating material is produced, for example, by the following first to fifth production methods.

[0044] In the first manufacturing method, first, a polymer gel is prepared by any one of the following methods (1) to (4) (preparation step). In the following methods (1) to (4), the stimuli-responsive polymer gel is prepared by crosslinking at least one of a stimuli-responsive polymer and a hydrophilic polymer.

[0045] (1) The above-mentioned stimuli-responsive polymer material and a hydrophilic polymer with strong moisture and water absorption properties are cross-linked to form an interpenetrating polymer network (IPN) structure.

[0046] In this method, a crosslinked network of a crosslinked stimuli-responsive polymer is formed by polymerizing and crosslinking the monomers that make up the stimuli-responsive polymer (step 1), and then, in the presence of the crosslinked network, the monomers that make up the hydrophilic polymer are polymerized and crosslinked (step 2).

[0047] (2) A semi-IPN structure is formed by crosslinking only either the stimuli-responsive polymer or the hydrophilic polymer.

[0048] In this method, a crosslinked network of crosslinked stimuli-responsive polymers is formed by polymerizing and crosslinking monomers constituting the stimuli-responsive polymer (Step 1), and a semi-interpenetrating polymer network structure consisting of the crosslinked network and a linear hydrophilic polymer is formed by polymerizing monomers constituting the hydrophilic polymer in the presence of the crosslinked network (Step 2). Alternatively, in the above method, a linear stimuli-responsive polymer is produced by polymerizing monomers constituting the stimuli-responsive polymer (Step 1), and a semi-interpenetrating polymer network structure consisting of the linear stimuli-responsive polymer and a crosslinked network of crosslinked hydrophilic polymers is formed by polymerizing and crosslinking monomers constituting the hydrophilic polymer in the presence of the linear stimuli-responsive polymer (Step 2).

[0049] (3) Only the stimuli-responsive polymer is crosslinked.

[0050] (4) Both the stimuli-responsive polymer and the hydrophilic polymer are cross-linked together (copolymerization).

[0051] In the methods (1) to (4), the polymerization method for polymerizing the monomers is not particularly limited, and suitable examples include radical polymerization, ionic polymerization, polycondensation, and ring-opening polymerization. The solvent used in the polymerization may be appropriately selected depending on the monomers, and suitable examples include water, phosphate buffer, Tris buffer, acetate buffer, methanol, and ethanol.

[0052] The polymerization initiator is not particularly limited, and examples that can be suitably used include persulfates such as ammonium persulfate and sodium persulfate; hydrogen peroxide; peroxides such as t-butyl hydroperoxide and cumene hydroperoxide; azobisisobutyronitrile; and benzoyl peroxide. Among these polymerization initiators, initiators that exhibit oxidizing properties, such as persulfates and peroxides, can also be used as redox initiators with, for example, sodium hydrogen sulfite or N,N,N',N'-tetramethylethylenediamine. Alternatively, light, radiation, or the like may be used as the initiator.

[0053] The polymerization temperature is not particularly limited, but is usually 5° C. to 80° C. The polymerization time is not particularly limited, but is usually 4 hours to 48 hours.

[0054] The concentrations of the monomer, crosslinker, etc. during polymerization are not particularly limited as long as they are concentrations that allow the stimuli-responsive polymer, the hydrophilic polymer, or crosslinked products thereof to be obtained. The concentration of the polymerization initiator is also not particularly limited and may be selected appropriately.

[0055] In the above methods (1) and (2), the method of forming a crosslinked network of a crosslinked stimuli-responsive polymer or a crosslinked hydrophilic polymer by polymerizing and crosslinking a monomer may be a method of polymerizing a monomer in the presence of a crosslinking agent, or a method of polymerizing a monomer to form a polymer and then crosslinking the polymer with a crosslinking agent.

[0056] In the above methods (1) and (2), in the first step, polymerization conditions or crosslinking conditions may be appropriately selected so as not to form crosslinks between the polymer formed in the second step or its crosslinked product.

[0057] In the methods (1) and (2), the monomers constituting the stimuli-responsive polymer, the monomers constituting the hydrophilic polymer, and the crosslinking agent are as described above in the explanations of the "crosslinked thermoresponsive polymer" and "crosslinked hydrophilic polymer."

[0058] In the methods (1) and (2), a stimuli-responsive polymer or a crosslinked product thereof is produced (step 1), and then a hydrophilic polymer or a crosslinked product thereof is produced in the presence of the obtained stimuli-responsive polymer or a crosslinked product thereof (step 2). Methods (1) and (2) are not limited to this, and a hydrophilic polymer or a crosslinked product thereof may be produced first, and then a stimuli-responsive polymer or a crosslinked product thereof may be produced in the presence of the obtained hydrophilic polymer or a crosslinked product thereof.

[0059] The polymer gel prepared as described above is dried to prepare a dried product (drying step), and the dried product is allowed to absorb a solution containing the active ingredient (absorbing step).

[0060] In the preparation process, multiple or single stimuli-responsive polymer materials and multiple or single hydrophilic polymers, which are components of the impregnating material, are mixed, and then each is crosslinked to form a gel, or one is crosslinked and gelled and then immersed in an aqueous solution of the other to crosslink while impregnated with the aqueous solution, or the other is crosslinked alone. In the drying process, the stimuli-responsive polymer gel with an IPN or semi-IPN structure obtained by gelation is freeze-dried or heat-dried to create a dried product.

[0061] In the absorption process, the dried gel made of the dried stimuli-responsive polymer gel is placed in an environment without external stimuli and is impregnated with a solution containing the active ingredient by either immersing it in the impregnation solution or spraying the solution. In the case of a temperature-responsive polymer gel, in order to apply heat as an external stimulus during use, the aqueous solution containing the active ingredient is impregnated by immersion or spraying it under a temperature condition below the LCST.

[0062] In the second manufacturing method, first, a mixture is prepared by mixing a stimuli-responsive polymer and a hydrophilic polymer, which are components of a stimuli-responsive polymer gel having an IPN structure, a semi-IPN structure, or a copolymer structure before crosslinking, with an active ingredient to be impregnated (mixing step). The active ingredient to be mixed here may be water-soluble, water-insoluble, or hydrophobic, as will be described in the sixth embodiment below.

[0063] Next, a crosslinking component (crosslinking agent, crosslinking accelerator, etc.) is added to the mixture, or the mixture is immersed in a crosslinking agent to gel the mixture, thereby creating a stimuli-responsive polymer gel impregnated with the active ingredient (gelation step). At this time, it is the constituent materials of the impregnating material that are crosslinked to form the gel structure, but the active ingredient to be impregnated is not crosslinked.

[0064] In the mixing process, the active ingredient is mixed in while mixing the multiple stimuli-responsive polymer materials and hydrophilic polymer materials that are components of the impregnation material. The mixture is then crosslinked and gelled with the active ingredient encapsulated in the polymer network structure.

[0065] In the gel produced by the second manufacturing method, the stimuli-responsive polymer gel containing the active ingredient obtained by crosslinking may be used as is (while kept wet), or the stimuli-responsive polymer gel may be further dried (drying step). In the second manufacturing method, the gel contains the active ingredient whether it is in a dry or wet state, and if it is in a wet gel state, the active ingredient is released along with water in response to a stimulus. Even when using a dried gel, it can be immersed in water, sprayed with an appropriate amount of water, or placed in a high-humidity, low-temperature environment (below the temperature-sensitive temperature) to absorb water or moisture and become impregnated with the water-soluble active ingredient.

[0066] In the third production method, first, in the above-mentioned preparation step (3), a hydrophilic polymer may not be used. In this method, a stimuli-responsive polymer may be mixed in addition to crosslinking the stimuli-responsive polymer.

[0067] Next, the polymer gel thus prepared is mixed with the active ingredient to be impregnated to prepare a mixture (mixing step).

[0068] Then, a crosslinking component (crosslinking agent, crosslinking accelerator, etc.) is added to the mixture, or the mixture is immersed in a crosslinking agent to gel the mixture, thereby creating a stimuli-responsive polymer gel impregnated with the active ingredient (gelation step). At this time, it is the constituent materials of the impregnating material that are crosslinked to form the gel structure, but the active ingredient to be impregnated is not crosslinked.

[0069] In the fourth manufacturing method, first, a mixture is prepared by mixing the stimuli-responsive polymer with the active ingredient to be impregnated (mixing step). Next, a crosslinking component (crosslinking agent, crosslinking accelerator, etc.) is added to the mixture, or the mixture is immersed in a crosslinking agent to gel the mixture, thereby preparing a stimuli-responsive polymer gel to be impregnated with the active ingredient (gelation step). In this case, as in the gelation step in the third manufacturing method, it is the constituent materials of the impregnating material that are crosslinked to form the gel structure, and the active ingredient is not crosslinked.

[0070] In the third and fourth production methods, the stimuli-responsive polymer may be dried after the gelling step (drying step).

[0071] In the fifth manufacturing method, first, as in the third manufacturing method, a stimuli-responsive polymer gel is prepared by crosslinking or mixing stimuli-responsive polymers (preparation step). Next, the polymer gel thus prepared is dried to produce a dried body (drying step). Then, a solution containing an active ingredient is absorbed into the dried body (absorption step).

[0072] [Embodiment 1] The first embodiment of the present invention will be described below with reference to FIG.

[0073] FIG. 1 is a perspective view showing the configuration of an impregnated material 1 according to this embodiment.

[0074] As shown in Fig. 1, the impregnating material 1 is formed in the shape of a rectangular plate. The impregnating material 1 contains the temperature-responsive polymer gel 11, which is the temperature-responsive polymer gel described above. The temperature-responsive polymer gel 11 itself may constitute the impregnating material 1, or the impregnating material 1 may be formed by being formed on a substrate (metal, plastic, wood, paper, etc.).

[0075] The temperature-responsive polymer gel 11 is made of a material or composition that has an LCST that is slightly lower than the body temperature (skin temperature) of a human being.

[0076] Thus, the temperature-responsive polymer gel 11, whose LCST is slightly lower than human body temperature, exhibits hydrophilic properties when the environmental temperature is below the LCST, and retains solutions containing active ingredients such as beauty serums, medicinal liquids, etc. Furthermore, when the temperature-responsive polymer gel 11 is heated by being applied to human skin and its temperature exceeds the LCST, it exhibits hydrophobic properties and releases the solution (active ingredient).

[0077] This allows the impregnated material 1 to deliver the active ingredient to the skin without being pressed or rubbed against the skin.

[0078] Furthermore, in cosmetic and medical applications, when the solution impregnated into the impregnated material 1 runs out, the impregnated material 1 can be re-impregnated with the solution in a temperature environment below the LCST, allowing the impregnated material 1 to be used multiple times in a single treatment. Also, by impregnating the impregnated material 1 with a different active ingredient each time the solution is re-impregnated, a different active ingredient can be impregnated each time.

[0079] Since the impregnated material 1 is held by the user when used, if the temperature of the part touched by the hand reaches or exceeds the LCST, the solution will be released from that part. To prevent this inconvenience, it is preferable that only the part of the impregnated material 1 that comes into contact with the skin is exposed and that the impregnated material 1 is covered by a container or the like so that the temperature of the hand is not transmitted to the surrounding area. This configuration may also be adopted in the second to fifth embodiments described below.

[0080] [Embodiment 2] The second embodiment of the present invention will be described below with reference to FIG.

[0081] FIG. 2 is a perspective view showing the configuration of the impregnating material 2 according to this embodiment.

[0082] The impregnated material 1 of the first embodiment described above can maintain its hydrophilicity and retain a solution when the ambient temperature is low, unless it is heated to a temperature above the LCST by coming into contact with the skin, etc. However, when the ambient temperature is above the LCST, the impregnated material 1 has the disadvantage of releasing the solution even when it is not in contact with the skin.

[0083] In this embodiment, a configuration that can suppress such inconvenience will be described.

[0084] 2, the impregnating material 2 is formed in the shape of a rectangular plate. The impregnating material 2 contains a temperature-responsive polymer gel 21, which is a temperature-responsive polymer gel having the above-mentioned LCST, and a temperature-responsive polymer gel 22 (co-stimuli-responsive polymer gel). The temperature-responsive polymer gels 21 and 22 are laminated.

[0085] Like the temperature-responsive polymer gel 21, the temperature-responsive polymer gel 22 is a stimulus-responsive polymer gel whose affinity for water changes reversibly in response to heat, and reversibly absorbs and releases water in response to changes in temperature. However, the temperature-responsive polymer gel 22 differs from the temperature-responsive polymer gel 21 in that the temperature-responsive polymer gel 22 is a polymer gel that has an upper critical solution temperature (UCST, sometimes referred to as "UCST" in the following description).

[0086] The temperature-responsive polymer gel 22 exhibits hydrophobicity at temperatures below a predetermined UCST (phase change level), but exhibits hydrophilicity at temperatures above the UCST. UCST refers to the temperature at which, when a polymer is dissolved in water, it becomes hydrophobic and insoluble in water at low temperatures, but becomes hydrophilic and soluble at a certain temperature or above.

[0087] Furthermore, the temperature-responsive polymer that constitutes the temperature-responsive polymer gel 22 is a betaine polymer, which is a dipolar polymer. Betaine polymers have both ionic groups, a positively charged amino group and a negatively charged sulfonic acid group, in the same side chain. Representative betaine polymers include sulfobetaine, carbobetaine, and phosphobetaine polymers. Sulfobetaine polymers include quaternary esters or amides of methacrylic acid, quaternized polypyrrolidinium compounds, ionene, polyvinylpyrrolidinium, and polyvinylimidazolium compounds.

[0088] When sulfobetaine is crosslinked with methylenebisacrylamide or other compounds, a gel exhibiting UCST can be obtained. An example of such a gel is DMAAPS (N,N-dimethyl acrylamide propyl ammonium propanesulfonate). Further examples of such gels include zwitterionic polymers, amides or esters of methacrylic acid, and quaternized pyrrolidinium compounds. Zwitterionic polymers, like carbobetaine polymers, have a negatively charged carboxyl group and a positively charged amino group on the same side chain, and their structure is characterized by heterocyclic or aromatic vinyl compounds. In amides or esters of methacrylic acid, the quaternized nitrogen is substituted with alkoxy groups of varying chain lengths. Quaternized pyrrolidinium compounds contain linear or branched alkyl carboxyl groups.

[0089] An example of a carbobetaine polymer is ethyl-3-propylaminocrotonate acrylic acid (CROPRO-AA). An example of a phosphobetaine polymer is o-[[2-(methacryloyloxy)ethyloxy]phosphonyl]choline (MPC), which contains a phosphate group as the active anionic group and a quaternized ammonium group as the active cationic group.

[0090] Other examples of phosphobetaine polymers include polyampholytes, which are formed by copolymerization of the negatively charged hydrophilic component sodium styrene sulfonate (SSS) with the positively charged hydrophobic component vinylbenzyl trimethylammonium chloride (VBTA). Further examples of phosphobetaine polymers include copolymers of hydrogen-bonding monomers and hydrophobic monomers. Examples of such copolymers include poly(N-acryloylglycinamide), poly(N-acryloylaspartamide), polyacrylamide-co-acrylonitrile, and poly(N-vinylimidazole-co-1-vinyl-2-hydroxymethylimidazole).

[0091] Other temperature-responsive polymers include polymers containing the nucleic acid base uracil in their side chains, triblock copolymers of polyethylene oxide and poly(L-lactic acid), gels synthesized by copolymerizing ureido-containing monomers with crosslinker monomers, styrene-methacrylic acid copolymers, orthochlorostyrene-parachlorostyrene copolymers, chlorinated polyethylene, and their derivatives. Ureido polymers can be obtained by adding potassium cyanate to polymers containing primary amines, and poly(allylamine-co-allylurea) (PAU) can be prepared by ureidation of the primary amino groups of polyallylamine with potassium cyanate. Like the PAAm-PAAc IPN gel, UCST gels can be prepared by IPN or semi-IPN or copolymerization of these UCST polymers with hydrophilic polymers such as acrylic acid and alginic acid under appropriate conditions, releasing water at low temperatures and swelling and absorbing water at high temperatures. Many other UCST gels exist, and they can be prepared using a variety of combinations of materials.

[0092] Next, an example of a combination of the LCST setting of the temperature-responsive polymer gel 21 and the UCST setting of the temperature-responsive polymer gel 22 will be described. In this example, the body temperature is 37°C, the LCST is 33°C, and the UCST is 38°C.

[0093] When the environmental temperature is 27°C, the temperature-responsive polymer gel 21 exhibits hydrophilicity, while the temperature-responsive polymer gel 22 exhibits hydrophobicity. At this time, the temperature-responsive polymer gel 21 is in a swollen state where it retains the solution, and the temperature-responsive polymer gel 22 is in a contracted state where it does not absorb the solution.

[0094] When the impregnating material 2 comes into contact with human skin, the temperature-responsive polymer gel 21 is heated to a temperature above the LCST and exhibits hydrophobicity, thereby releasing the solution. On the other hand, the temperature-responsive polymer gel 22 is heated only to a temperature below the UCST and maintains its hydrophobicity, so it does not absorb the solution released from the temperature-responsive polymer gel 21. This causes the solution to seep out of the impregnating material 2 and be applied to the skin.

[0095] When the impregnating material 2 is left in an environmental temperature (e.g., 41°C) that exceeds body temperature, the temperature-responsive polymer gel 21 is heated to a temperature above the LCST and becomes hydrophobic, while the temperature-responsive polymer gel 22 is heated to a temperature above the UCST and becomes hydrophilic. At this time, the temperature-responsive polymer gel 21 enters a contracted state where it does not absorb the solution and releases the solution. On the other hand, the temperature-responsive polymer gel 22 enters a swollen state and absorbs the solution released from the temperature-responsive polymer gel 21.

[0096] In this temperature environment, when the impregnating material 2 is in contact with human skin, the temperature of the temperature-responsive polymer gel 21 drops to the temperature of the skin, but remains above the LCST, so the temperature-responsive polymer gel 21 maintains its contracted state. Meanwhile, the temperature of the temperature-responsive polymer gel 22 drops below the UCST, so the temperature-responsive polymer gel 22 changes from hydrophilic to hydrophobic, contracts, and releases the retained solution. This causes the solution to seep out of the impregnating material 2 and be applied to the skin. At this time, since it is the temperature-responsive polymer gel 22 that is primarily impregnated with the solution, the surface of the temperature-responsive polymer gel 22 on the back side, which is opposite the surface of the temperature-responsive polymer gel 21 on the front side, comes into contact with the skin, thereby more effectively supplying the solution to the skin.

[0097] Furthermore, when the environmental temperature in which the impregnating material 2 is placed drops from the above-mentioned high temperature to a temperature below the LCST, for example by moving the impregnating material 2 to a cold place, the temperature-responsive polymer gel 21 becomes hydrophilic, while the temperature-responsive polymer gel 22 becomes hydrophobic. At this time, the temperature-responsive polymer gel 22 contracts and releases the solution it had held, while the temperature-responsive polymer gel 21 becomes hydrophilic and absorbs the solution released from the temperature-responsive polymer gel 22. When the impregnating material 2 stored in a cold place comes into contact with the skin, the temperature-responsive polymer gel 21 transitions to a hydrophobic state due to the skin temperature, causing the impregnated solution to ooze out and be supplied to the skin.

[0098] In this manner, the impregnating material 2 of this embodiment is formed by laminating the temperature-responsive polymer gels 21 and 22, each having an LCST and a UCST that are different temperatures.

[0099] This allows the solution released from the temperature-responsive polymer gel 21 to be absorbed by the temperature-responsive polymer gel 22 when the temperature stimulus reaches or exceeds the LCST. Also, when the temperature falls below the UCST, the solution released from the temperature-responsive polymer gel 22 can be absorbed by the temperature-responsive polymer gel 21. This reduces waste, which occurs when the temperature-responsive polymer gel 21 releases a solution due to the environmental temperature even when the impregnating material 2 is not in contact with the skin and the solution cannot be recovered.

[0100] [Embodiment 3] The third embodiment of the present invention will be described below with reference to FIGS.

[0101] FIG. 3 is a perspective view showing the configuration of the impregnating material 3 according to this embodiment.

[0102] In the impregnating material 2 of the second embodiment described above, the direction of solution release and absorption is fixed between the temperature-responsive polymer gels 21 and 22, and the solution is transferred only at the laminated surface. Therefore, when the ambient temperature becomes high, the efficiency of solution transfer from the temperature-responsive polymer gel 21 to the temperature-responsive polymer gel 22 is poor. Therefore, repeated changes in the ambient temperature cause the disadvantage of a decrease in the amount of solution that can be supplied to the skin.

[0103] In this embodiment, a configuration that can prevent such inconveniences from occurring will be described.

[0104] As shown in Fig. 3, the impregnating material 3 is formed in the shape of a rectangular sheet. The impregnating material 3 contains a plurality of temperature-responsive polymer gels 31, which are the temperature-responsive polymer gels described above, and a plurality of temperature-responsive polymer gels 32 (costimuli-responsive polymer gels). The temperature-responsive polymer gels 31 and 32 are arranged in a planar shape and joined to each other at their sides to form a flat plate. The temperature-responsive polymer gels 31 and 32 are formed in the shape of identical plates and are arranged so as to appear alternately in the row and column directions to form a checkered pattern.

[0105] The temperature-responsive polymer gel 31 is a temperature-responsive polymer gel having an LCST, similar to the temperature-responsive polymer gel 21 in embodiment 2. The temperature-responsive polymer gel 32 is a stimulus-responsive polymer gel having a UCST, similar to the temperature-responsive polymer gel 22 in embodiment 2.

[0106] The impregnating material 3 configured in this manner, like the impregnating material 2 of the second embodiment, can absorb a solution released from the temperature-responsive polymer gel 31 into the temperature-responsive polymer gel 32 through the joint surface between the temperature-responsive polymer gels 31 and 32 when the temperature reaches the LCST or higher. Furthermore, the impregnating material 3 can also absorb a solution released from the temperature-responsive polymer gel 32 into the temperature-responsive polymer gel 31 through the joint surface when the temperature falls below the UCST. This makes it possible to prevent waste, which occurs when the temperature-responsive polymer gel 31 releases a solution due to the environmental temperature but is unable to collect it, even though the impregnating material 3 is not in contact with the skin.

[0107] In the impregnating material 3, the temperature-responsive polymer gel 31 is in contact with the side surfaces of the four temperature-responsive polymer gels 32 at its side, and the temperature-responsive polymer gel 32 is in contact with the side surfaces of the four temperature-responsive polymer gels 31 at its side. The temperature-responsive polymer gels 31 and 32 allow free movement of the solution on their side surfaces.

[0108] Therefore, each of the temperature-responsive polymer gels 31, 32 is formed to be sufficiently smaller than the temperature-responsive polymer gels 21, 22 of the impregnation material 2. This allows the contact area at the side surfaces of the temperature-responsive polymer gels 31, 32 to be larger than the contact area of ​​the temperature-responsive polymer gels 21, 22. Therefore, the solution can be efficiently transferred between the temperature-responsive polymer gels 31, 32.

[0109] It is also possible to adjust the amount of moisture and moisture containing active ingredients moving between gels, for example, the amount of movement from the temperature-responsive polymer gel 31 to the temperature-responsive polymer gel 32, or the amount of movement from the temperature-responsive polymer gel 32 to the temperature-responsive polymer gel 31. In this case, in addition to stimuli such as temperature, the shape of the gel interface also plays a role.

[0110] To increase the amount of moisture movement, the joining surface where the temperature-responsive polymer gels 31 and 32 are joined is made wider than the joining surface perpendicular to the surface formed by the joining of the temperature-responsive polymer gels 31 and 32. Methods for achieving this include making the joining surface inclined relative to the bottom surfaces of the temperature-responsive polymer gels 31 and 32, rather than making the joining surface perpendicular to the bottom surfaces, or forming the joining surface into a complex shape with projections and recesses.

[0111] The inclination of the bonding surface can be achieved by forming the temperature-responsive polymer gels 31, 32 so that each side is inclined, or by cutting the side of the temperature-responsive polymer gels 31, 32 at an angle. Furthermore, the bonding surface can be formed with an uneven shape by forming the gel in a mold with unevenness. Increasing the area of ​​the bonding surface in this way increases the amount of water that moves between the different gels.

[0112] Conversely, to reduce the amount of moisture migration, in addition to making the joining surface perpendicular to the bottom surface, another gel, such as a gel that is not stimuli-responsive or a gel that is stimuli-responsive but does not contain an active ingredient, can be sandwiched between the joining surfaces. When a temperature-responsive polymer gel that has a blocking property against moisture migration, acting as a shutter, is sandwiched between the temperature-responsive polymer gels 31 and 32, the temperature-responsive polymer gel is called a blocking polymer gel. If the temperature-sensitive point of the blocking polymer gel is set below the temperature-sensitive point of the temperature-responsive polymer gel 31, the temperature-responsive polymer gel will first become hydrophobic, preventing moisture migration from the temperature-responsive polymer gel 31 to the temperature-responsive polymer gel 32. The amount of moisture migration can be controlled by the size of the gel that functions as a shutter.

[0113] To produce a shielding polymer gel, a polymer gel that is not stimuli-responsive is inserted into the joining surface of the temperature-responsive polymer gels 31 and 32 and crosslinked, or a gel that changes phase in response to the same temperature stimulus is inserted into the joining surface and crosslinked.

[0114] In this embodiment, a configuration has been described in which a plurality of temperature-responsive polymer gels 31 having an LCST and a plurality of temperature-responsive polymer gels 32 having a UCST are mixed and arranged. However, the present invention is not limited to this, and the impregnating material 3 may contain only a plurality of temperature-responsive polymer gels 31.

[0115] Furthermore, the LCSTs of the multiple temperature-responsive polymer gels 31 do not all have to be the same, and some of the temperature-responsive polymer gels 31 may be different from the other temperature-responsive polymer gels 31. This allows the temperature-responsive polymer gels 31 with different LCSTs to release active ingredients at different times by changing the temperature (level of stimulus). This makes it possible to extend the period for releasing the active ingredients. In addition, the temperature-responsive polymer gels 31 may be impregnated with solutions containing different active ingredients depending on the LCST. This allows the different active ingredients to be released at different times.

[0116] In the above case, as described above, mixing of the components can be prevented by controlling the shape of the joining surfaces of the plurality of temperature-responsive polymer gels 31 with different LCSTs. In addition, by utilizing a shielding polymer gel, appropriate amounts of components that were separate until just before application can be intentionally mixed together when applied to a target such as the skin.

[0117] In addition, in this embodiment, in order to increase the amount of moisture movement, the joining surface where the temperature-responsive polymer gels 31 and 32 are joined is described as being wider than the joining surface perpendicular to the surface formed by the joining of the temperature-responsive polymer gels 31 and 32. Alternatively, the joining surface between adjacent temperature-responsive polymer gels equivalent to the temperature-responsive polymer gel 31 may be wider than the joining surface perpendicular to the surface formed by the joining of the temperature-responsive polymer gels. This can increase the amount of moisture movement between these temperature-responsive polymer gels.

[0118] Next, a modification of this embodiment will be described.

[0119] Fig. 4(a) is a plan view showing the configuration of an impregnating material 3A according to a first modified example, and Fig. 4(b) is a perspective view showing the configuration of the impregnating material 3A. Fig. 5(a) is a plan view showing the configuration of an impregnating material 3B according to a second modified example, and Fig. 5(b) is a perspective view showing the configuration of the impregnating material 3B. Fig. 6 is a perspective view showing the configuration of an impregnating material 3C according to a third modified example. Fig. 7 is a perspective view showing the configuration of an impregnating material 3D according to a fourth modified example.

[0120] First, a first modified example will be described. As shown in Figures 4(a) and 4(b), the impregnating material 3A according to the first modified example is formed in a rectangular sheet shape and contains a plurality of temperature-responsive polymer gels 31 and 32.

[0121] The temperature-responsive polymer gel 32 is formed in a rectangular shape that forms the overall outline of the impregnating material 3A. A plurality of temperature-responsive polymer gels 31 are formed in a thickness range from the surface of the temperature-responsive polymer gel 32 to the middle position in the thickness direction of the temperature-responsive polymer gel 32 so as to be exposed on the surface of the temperature-responsive polymer gel 32. The temperature-responsive polymer gels 31 are arranged alternately at predetermined intervals and are also arranged at a predetermined interval from the outer peripheral edge of the temperature-responsive polymer gel 32.

[0122] 4(a) and 4(b), the impregnating material 3A has an island-in-a-sea structure in which the temperature-responsive polymer gel 31 is dispersed in the temperature-responsive polymer gel 32. In contrast, although not shown, the impregnating material 3A may have an island-in-a-sea structure in which the temperature-responsive polymer gels 31, 32 are disposed in the opposite position to the above, that is, the temperature-responsive polymer gel 32 is dispersed in the temperature-responsive polymer gel 31.

[0123] Next, a second modified example will be described. As shown in Figures 5(a) and 5(b), the impregnating material 3B according to the second modified example is formed in the shape of a rectangular sheet. The impregnating material 3B contains a plurality of temperature-responsive polymer gels 31 and a plurality of temperature-responsive polymer gels 32, which are the temperature-responsive polymer gels described above.

[0124] The impregnating material 3B has a first portion 301 and a second portion 302, and has a structure in which the first portion 301 and the second portion 302 are joined to each other at their sides. The first portion 301 has an island-in-a-sea structure in which the temperature-responsive polymer gel 32 is more abundant than the temperature-responsive polymer gel 31. The second portion 302 has an island-in-a-sea structure in which the temperature-responsive polymer gel 31 is more abundant than the temperature-responsive polymer gel 32.

[0125] The first portion 301 is made up of a surface layer 301a and a base layer 301b provided below the surface layer 301a. The second portion 302 is made up of a surface layer 302a and a base layer 302b provided below the surface layer 302a.

[0126] The surface layer 301a is composed of plate-like temperature-responsive polymer gels 31 and 32 formed in the same rectangular shape. In the surface layer 301a, the temperature-responsive polymer gels 31 and 32 are arranged in a plane and joined to each other at their sides to form a flat plate. The temperature-responsive polymer gels 31 and 32 in the surface layer 301a are arranged, for example, in three columns and three rows, with the temperature-responsive polymer gel 31 arranged in the center and eight temperature-responsive polymer gels 32 arranged to surround the temperature-responsive polymer gel 31.

[0127] The base layer 301b is made of a temperature-responsive polymer gel 32 and is formed into a flat plate having the same shape as the surface layer 301a.

[0128] The surface layer 302a is also composed of temperature-responsive polymer gels 31 and 32. In the surface layer 302a, the temperature-responsive polymer gels 31 and 32 are arranged in a plane and joined to each other at their sides to form a flat plate. The temperature-responsive polymer gels 31 and 32 in the surface layer 302a are also arranged, for example, in three columns and three rows, with the temperature-responsive polymer gel 32 arranged in the center and eight temperature-responsive polymer gels 31 arranged to surround the temperature-responsive polymer gel 32.

[0129] The base layer 302b is made of a temperature-responsive polymer gel 31 and is formed into a flat plate having the same shape as the surface layer 302a.

[0130] Next, a third modified example will be described. As shown in Fig. 6, the impregnating material 3C according to the third modified example is also formed in the shape of a rectangular sheet, and includes a plurality of temperature-responsive polymer gels 31 and a plurality of temperature-responsive polymer gels 32. The temperature-responsive polymer gels 31 and 32 are formed in the shape of long, thin plates, and are arranged alternately in a striped structure joined to each other at the side surfaces on the long sides, thereby forming a flat plate.

[0131] Next, a fourth modified example will be described. As shown in Fig. 7, the impregnating material 3D according to the fourth modified example is also formed in the shape of a rectangular sheet and contains a plurality of temperature-responsive polymer gels 31 and a plurality of temperature-responsive polymer gels 32. The impregnating material 3D has a first portion 311 and a second portion 312, and is structured such that the first portion 311 and the second portion 312 are joined to each other at their sides. The first portion 311 has a sea-island structure in which the temperature-responsive polymer gel 31 is more abundant than the temperature-responsive polymer gel 32. The second portion 312 has a sea-island structure in which the temperature-responsive polymer gel 32 is more abundant than the temperature-responsive polymer gel 31.

[0132] The first section 311 is composed of a surface layer 311a and a base layer 311b provided below the surface layer 311a. The surface layer 311a is composed of temperature-responsive polymer gels 31 and 32 formed in the shape of elongated plates, with temperature-responsive polymer gels 32 disposed on both sides of the temperature-responsive polymer gel 31. The temperature-responsive polymer gels 31 and 32 are joined together at their long side surfaces to form a flat plate. The base layer 311b is composed of the temperature-responsive polymer gel 32 and is formed as a flat plate having the same width and length as the surface layer 311a.

[0133] The second section 312 is composed of a surface layer 312a and a base layer 312b provided below the surface layer 312a. The surface layer 312a is composed of temperature-responsive polymer gels 31 and 32 formed in the shape of an elongated plate, with temperature-responsive polymer gels 31 disposed on both sides of the temperature-responsive polymer gel 32. The temperature-responsive polymer gels 31 and 32 are joined together at their long side surfaces to form a flat plate. The base layer 312b is composed of the temperature-responsive polymer gel 31 and is formed as a flat plate having the same width and length as the surface layer 312a.

[0134] Note that the base layer 311b does not have to have the same width and length as the surface layer 311a. Similarly, the base layer 312b does not have to have the same width and length as the surface layer 312a. From the viewpoint of water retention, it is more desirable that the size of the LCST layer be smaller than the size of the UCST layer. This is because, at the current technological level, LCST materials are more common and can be made into materials with high water retention.

[0135] The impregnating materials 3A to 3D configured as above can also obtain the same effects as those of the impregnating material 3 described above.

[0136] [Embodiment 4] The fourth embodiment of the present invention will be described below with reference to FIG.

[0137] FIG. 8 is a perspective view showing the configuration of the impregnating material 4 according to this embodiment.

[0138] 8, the impregnating material 4 has a plurality of temperature-responsive polymer gels 41, 42 and a water-permeable membrane 43 (permeable membrane). The temperature-responsive polymer gels 41, 42 are each formed in the form of particles, and are dispersed so as to be randomly arranged within the water-permeable membrane 43. The temperature-responsive polymer gels 41, 42 can be formed into particles by a known method such as sol drop crosslinking or emulsion polymerization.

[0139] The temperature-responsive polymer gel 41 is a stimulus-responsive polymer gel having an LCST, similar to the temperature-responsive polymer gel 21 in embodiment 2. The temperature-responsive polymer gel 42 is a stimulus-responsive polymer gel having a UCST, similar to the temperature-responsive polymer gel 22 in embodiment 2.

[0140] The water-permeable membrane 43 is a membrane that allows water to pass through, including a solution containing an active ingredient. The water-permeable membrane 43 is made of a material such as a polymer membrane that has water permeability. Furthermore, since the water-permeable membrane 43 comes into contact with the skin, it is preferable that the membrane be made of a material that is highly biocompatible.

[0141] The water-permeable membrane 43 may be made of a porous material that allows the active ingredient to pass through, such as a porous polymer sheet, mesh, gauze, or water-permeable cloth. By encasing a gel group (aggregate of particles) in such a material, the particulate temperature-responsive polymer gels 41, 42 can be randomly arranged. Alternatively, the impregnating material 4 may be constructed by inserting or forming the temperature-responsive polymer gels 41, 42 in advance in a thick porous water-permeable membrane or block.

[0142] The impregnating material 4 configured in this manner can, like the impregnating material 2 of the second embodiment, cause the temperature-responsive polymer gel 42 to absorb the solution released from the temperature-responsive polymer gel 41 when the temperature reaches the LCST or higher. Furthermore, the impregnating material 4 can also cause the temperature-responsive polymer gel 41 to absorb the solution released from the temperature-responsive polymer gel 42 when the temperature falls below the UCST. This makes it possible to reduce waste, which occurs when the temperature-responsive polymer gel 41 releases a solution due to the environmental temperature but is unable to recover it, even though the impregnating material 4 is not in contact with the skin due to the temperature environment.

[0143] Furthermore, since the temperature-responsive polymer gels 41 and 42 are formed in a particulate form, there is no directionality in the absorption and release of the solution, which allows the solution to be efficiently transferred between the temperature-responsive polymer gels 41 and 42.

[0144] Although the impregnating material 4 of this embodiment is provided with a plurality of different types of temperature-responsive polymer gels 41 and 42, only a plurality of temperature-responsive polymer gels 41 may be provided.

[0145] Furthermore, in a configuration in which only a plurality of temperature-responsive polymer gels 41 are provided, the LCSTs of the plurality of temperature-responsive polymer gels 41 do not all have to be the same, and some of the temperature-responsive polymer gels 41 may be different from the other temperature-responsive polymer gels 41. This allows the temperature-responsive polymer gels 41 with different LCSTs to release active ingredients at different times by changing the environmental temperature. This therefore makes it possible to extend the period during which the active ingredients are released. In addition, the temperature-responsive polymer gels 31 may be impregnated with solutions containing different active ingredients depending on the LCST. This allows different active ingredients to be released at different times.

[0146] Furthermore, by dispersing the temperature-responsive polymer gels 41 and 42 in a sol rather than in the water-permeable membrane 43, the gel can be used as an ointment.

[0147] [Embodiment 5] The fifth embodiment of the present invention will be described below with reference to FIG.

[0148] FIG. 9 is a perspective view showing the configuration of the impregnating material 5 according to this embodiment.

[0149] As shown in Fig. 9, the impregnating material 5 is formed in the shape of a rectangular sheet. The impregnating material 5 contains a plurality of temperature-responsive polymer gels 51 to 53, which are temperature-responsive polymer gels having an LCST, similar to the temperature-responsive polymer gel 21 in the second embodiment. The temperature-responsive polymer gels 51 to 53 are arranged in a planar shape and joined to each other at their sides to form a flat plate. The temperature-responsive polymer gels 51 to 53 are formed in the shape of identical plates and arranged in the same order in the row and column directions, and are joined to different temperature-responsive polymer gels 51 to 53, respectively.

[0150] The LCSTs of the temperature-responsive polymer gels 51 to 53 are different from one another. For example, the LCST of the temperature-responsive polymer gel 51 is 33° C., the LCST of the temperature-responsive polymer gel 52 is 38° C., and the LCST of the temperature-responsive polymer gel 53 is 41° C. These LCSTs are merely examples, and the LCSTs of the temperature-responsive polymer gels 51 to 53 are not limited to these examples.

[0151] The impregnated material 5 thus configured contains temperature-responsive polymer gels 51 to 53, each with a different LCST. This allows the temperature-responsive polymer gels 51 to 53 with different LCSTs to release the active ingredient at different times by changing the environmental temperature. This allows the active ingredient to be applied to the skin with a time lag. It also allows the active ingredient to be applied precisely to the affected area or region according to the temperature (fever due to inflammation, etc.).

[0152] Specifically, when the surface of the impregnating material 5 comes into contact with the skin and the temperature of the impregnating material 5 becomes equal to or higher than the LCST of the temperature-responsive polymer gel 51 and lower than the LCST of the temperature-responsive polymer gels 52 and 53, the solution is released from the surface of the temperature-responsive polymer gel 51. When the temperature of the impregnating material 5 becomes equal to or higher than the LCST of the temperature-responsive polymer gel 52 and lower than the LCST of the temperature-responsive polymer gel 53 by heating the impregnating material 5 with a heater or the like, the solution is released from the surface of the temperature-responsive polymer gel 52. When the temperature of the impregnating material 5 becomes equal to or higher than the LCST of the temperature-responsive polymer gel 53 by increasing the heating temperature of the impregnating material 5, the solution is released from the surface of the temperature-responsive polymer gel 53.

[0153] Now, let us assume that the temperature of the impregnating material 5 does not exceed the LCST of the temperature-responsive polymer gels 52 and 53 when the surface of the impregnating material 5 comes into contact with the skin. In this state, the solution released from the temperature-responsive polymer gel 51 moves to the temperature-responsive polymer gels 52 and 53 via the interface between the temperature-responsive polymer gel 51 and the temperature-responsive polymer gels 52 and 53. However, the temperature-responsive polymer gel 51 releases more solution from the surface that is in direct contact with the skin than from the side that is in contact with the temperature-responsive polymer gels 52 and 53. As a result, the amount of solution that moves from the temperature-responsive polymer gel 51 to the temperature-responsive polymer gels 52 and 53 is small.

[0154] Furthermore, when the impregnated material 5 is left standing in a high environmental temperature that is equal to or higher than the LCST of the temperature-responsive polymer gel 53, the solution is released from the surfaces of the temperature-responsive polymer gels 51 to 53 and moves over a wide area at the respective bonding surfaces. This phenomenon does not occur in a temperature environment lower than human body temperature.

[0155] In the above-mentioned high-temperature environment, a skin layer (hydrophobic layer) is formed on the surface of the hydrophobicized temperature-responsive polymer gels 51 to 53. After the solution near the surface is released in the initial high-temperature environment, the solution deep inside the temperature-responsive polymer gels 51 to 53 moves to the region with a higher LCST. In other words, the solution in the temperature-responsive polymer gel 51 moves to the adjacent temperature-responsive polymer gel 52, and the solution in the temperature-responsive polymer gel 52 moves to the temperature-responsive polymer gel 53. As a result, not all of the solution is released, and it is possible to reduce the loss of solution that is released from the surface and lost unused.

[0156] The movement of moisture and moisture containing active ingredients between gels, for example, the amount of movement from the temperature-responsive polymer gel 51 to the temperature-responsive polymer gel 52 or from the temperature-responsive polymer gel 52 to the temperature-responsive polymer gel 53, can be adjusted in the same manner as in embodiment 3. In this case, to increase the amount of moisture movement, the joining surface where the temperature-responsive polymer gels 51 and 52 are joined or the joining surface where the temperature-responsive polymer gels 52 and 53 are joined is widened. To reduce the amount of moisture movement, in addition to making the joining surface perpendicular to the bottom surface, a shielding polymer gel is inserted between each joining surface of the temperature-responsive polymer gels 51 to 52.

[0157] The temperature-responsive polymer gels 51 to 53 may be impregnated with solutions containing different active ingredients. This allows the temperature-responsive polymer gels 51 to 53 to release different active ingredients at different times. In this case, as described above, mixing of the components can be prevented by controlling the shape of the joining surfaces of the multiple temperature-responsive polymer gels 51 to 53 with different LCSTs. Alternatively, a shielding polymer gel can be used to intentionally mix appropriate amounts of ingredients that were separate until just before application, so that they can be mixed when applied to a target such as the skin.

[0158] Furthermore, the impregnating material 5 contains three types of temperature-responsive polymer gels 51 to 53 having LCSTs, but may contain two types or four or more types of temperature-responsive polymer gels.

[0159] Furthermore, the stimuli-responsive polymer gel can be made into a photoresponsive polymer gel. This allows the release of active ingredients only from the area irradiated with light, similar to or more precisely controlled than the case of a temperature-responsive polymer gel, or the release of the active ingredients can be controlled by promoting or suppressing it depending on the intensity of the light. Using the photoresponsive polymer gel over a wide area or in a pinpointed area can contribute to the appropriate treatment of the affected area. Note that photoresponsive polymer gels also include temperature-responsive polymer gels that incorporate materials that function as photothermal converters, such as carbon black, electrically conductive polymers, and metal particles.

[0160] [Embodiment 6] The sixth embodiment of the present invention will be described below with reference to FIG.

[0161] FIG. 10 is a perspective view showing the configuration of the applicator member 6 according to this embodiment.

[0162] 10, the application member 6 is formed in the shape of a rectangular plate. The application member 6 is made of an absorbent material 61 containing a stimulus-responsive polymer that reversibly changes between hydrophilic and hydrophobic properties in response to an external stimulus.

[0163] The stimulus-responsive polymer may be a polymer constituting the above-mentioned stimulus-responsive polymer gel, which allows the skin to be impregnated with and release active ingredients. The stimulus-responsive polymer has a tendency to absorb moisture when the external stimulus is below a predetermined level, and a tendency to release moisture when the external stimulus is above the predetermined level.

[0164] Active ingredients, such as cosmetically effective cosmetic ingredients and medically effective medicinal ingredients, are often water-soluble. However, water-insoluble, oil-soluble, and hydrophobic ingredients can also be impregnated and encapsulated in gels by using appropriate surfactants. For example, when impregnating an active ingredient using a double layer of hydrophilic and hydrophobic groups with a surfactant, the active ingredient is introduced along with the surrounding water or water-soluble ingredients, and is released as the gel shrinks when the gel undergoes a phase transition in response to a stimulus. Even when the active ingredient is included during gel preparation, the active ingredient is introduced into the dried gel by swelling with water, such as by moisture absorption or spraying, and is then released as the gel shrinks after receiving a stimulus. Active ingredients can also be encapsulated in water-insoluble or oil-soluble ingredients within water-soluble ingredients using emulsions.

[0165] The application member 6 configured as described above facilitates retention of active ingredients in beauty serums, medicinal solutions, etc. when the level of external stimuli is below a predetermined level, while facilitating the release of the active ingredients when the level of external stimuli is above the predetermined level. As a result, when the application member 6 is not in use, the stimuli applied to the application member 6 are kept below the predetermined level, making it easier for the active ingredients to be retained in the impregnated material. Furthermore, by applying a stimuli above the predetermined level to the application member 6, it is possible to facilitate the release of the active ingredients from the impregnated material.

[0166] Furthermore, by using heat as the external stimulus, for example, human body temperature (skin temperature), it is possible to release the active ingredient impregnated in the application member simply by contacting the application member with the skin. For example, when the temperature of an affected area is elevated due to a high fever, a cold, or ongoing inflammation, the active ingredient can be released only to the affected area.

[0167] As described above, the application member 6 allows the user to impregnate the application member 6 with the above-mentioned solution containing the desired active ingredient according to the application. Therefore, it can be suitably used for cosmetic applications, medical applications, etc., for applying the active ingredient to the skin. Furthermore, as with the above-mentioned impregnated materials 1 to 5, it is of course possible to apply the active ingredient to the skin without pressing or rubbing it against the skin.

[0168] 〔summary〕 The application member according to aspect 1 of the present invention contains a stimuli-responsive polymer that reversibly changes between hydrophilic and hydrophobic properties in response to an external stimulus, so as to enable the application of an active ingredient to the skin to be impregnated and released.

[0169] According to the above configuration, it is possible to impregnate the active ingredient with the material or release the active ingredient by applying an appropriate external stimulus.

[0170] The application member according to aspect 2 of the present invention may be, in the above aspect 1, more likely to absorb moisture when the level of the external stimulus is below a predetermined level, and more likely to release moisture when the level of the external stimulus is equal to or greater than the predetermined level.

[0171] According to the above configuration, when the level of external stimulus is below a predetermined level, the active ingredients of the beauty serum, medicinal solution, etc. are easily retained, while when the level of external stimulus is above the predetermined level, the active ingredients are easily released. As a result, when the application member is not in use, the stimulus applied to the application member 6 is kept below the predetermined level, making it easier for the active ingredients to be retained in the impregnated material. In addition, by applying a stimulus above the predetermined level to the application member, it is possible to make it easier for the active ingredients to be released from the impregnated material.

[0172] The application member according to aspect 3 of the present invention is the application member according to aspect 1 or 2 above, wherein the active ingredient may be water-soluble, water-insoluble, oil-based, or hydrophobic.

[0173] According to the above configuration, it is possible to easily impregnate the application member with the active ingredient.

[0174] In the application member according to Aspect 4 of the present invention, in any one of Aspects 1 to 3, the external stimulus may be heat or light.

[0175] According to the above configuration, for example, by using human body temperature (skin temperature) as an external stimulus, it is possible to release the active ingredient impregnated in the applicator simply by contacting the applicator with the skin. It is also possible to release the active ingredient impregnated in the applicator by irradiating the affected area with light.

[0176] The impregnated material according to the fifth aspect of the present invention is impregnated with an active ingredient and includes a stimuli-responsive polymer gel (temperature-responsive polymer gels 11, 21, 31, 41, 51 to 53) that absorbs the active ingredient when the level of an external stimulus is below a predetermined level, and releases the active ingredient when the level of the external stimulus is equal to or higher than the level.

[0177] According to the above configuration, the impregnating material retains the active ingredients of the beauty serum, medicinal solution, etc. when the level of the external stimulus is below a predetermined level, while releasing the active ingredients when the level of the external stimulus is above the predetermined level. As a result, when the impregnating material is not in use, the active ingredients are retained in the impregnating material by applying a stimulus below the predetermined level. Also, the active ingredients can be released from the impregnating material by applying a stimulus above the predetermined level to the impregnating material.

[0178] In the impregnated material according to a sixth aspect of the present invention, in the fifth aspect, the external stimulus may be heat or light.

[0179] According to the above configuration, when the temperature is below the above-mentioned level, the active ingredients of the beauty serum, medicinal solution, etc. are retained, while when the temperature is above the above-mentioned level, the active ingredients are released. As a result, for example, by setting the above-mentioned level to about human body temperature (skin temperature), simply by contacting the impregnating material with the skin, the temperature of the impregnating material exceeds the above-mentioned level, causing the active ingredients to be released from the impregnating material. In addition, it is also possible to release the active ingredients impregnated in the impregnating material by irradiating the affected area with light.

[0180] The impregnating material according to a seventh aspect of the present invention is the same as that of the fifth or sixth aspect, in which a plurality of the stimuli-responsive polymer gels are arranged in a planar manner and are joined to each other in a planar manner, and the levels of the respective stimuli-responsive polymer gels may be different.

[0181] According to the above configuration, the level of stimulation for releasing the active ingredient differs between the stimuli-responsive polymer gels. By changing the level of stimulation, the timing for releasing the active ingredient from each stimuli-responsive polymer gel can be made different. Therefore, the period for releasing the active ingredient can be extended.

[0182] The impregnating material according to an eighth aspect of the present invention is the same as that according to the fifth or sixth aspect, wherein a plurality of the stimuli-responsive polymer gels are arranged in a planar shape and bonded to one another, and the level of some of the stimuli-responsive polymer gels may be different from that of other stimuli-responsive polymer gels.

[0183] According to the above configuration, the level of stimulation for releasing the active ingredient differs between the stimuli-responsive polymer gels. By changing the level of stimulation, the timing for releasing the active ingredient from each stimuli-responsive polymer gel can be made different. Therefore, the period for releasing the active ingredient can be extended.

[0184] The impregnating material according to a ninth aspect of the present invention is the same as that of the fifth or sixth aspect, in which the stimuli-responsive polymer gel is formed into particles, and a plurality of particles are provided, and the particles are held in a material (permeable membrane 43) that can allow the active ingredient to permeate, and the level may be different for some stimuli-responsive polymer gels from that for other stimuli-responsive polymer gels.

[0185] According to the above configuration, since the level of stimulation differs between some stimuli-responsive polymer gels and other stimuli-responsive polymer gels, it is possible to change the degree of stimulation and release the active ingredient from the stimuli-responsive polymer gel at different times when different levels are reached, thereby extending the period during which the active ingredient is released.

[0186] The impregnated material according to a tenth aspect of the present invention is the material of any one of the seventh to ninth aspects, wherein the stimuli-responsive polymer gel may contain different active ingredients depending on the level.

[0187] With the above configuration, different active ingredients can be released at different times from each stimuli-responsive polymer gel by changing the level of stimulation.

[0188] The impregnated material according to aspect 11 of the present invention, in accordance with aspect 5 or 6 above, may further include an auxiliary stimulus responsive polymer gel (temperature responsive polymer gel 22, 32, 42) that releases the active ingredient when the intensity of the external stimulus is below a predetermined phase change level different from the level, and releases the active ingredient when the intensity of the external stimulus is equal to or greater than the phase change level.

[0189] According to the above configuration, the level at which the stimuli-responsive polymer gel changes its properties is different from the phase change level at which the auxiliary stimuli-responsive polymer gel changes its properties. This allows the active ingredient released from the stimuli-responsive polymer gel to be absorbed by the auxiliary stimuli-responsive polymer gel when the stimulus is equal to or greater than the level. Also, the active ingredient released from the auxiliary stimuli-responsive polymer gel can be absorbed by the stimuli-responsive polymer gel when the stimulus is lower than the level.

[0190] The impregnated material according to a twelfth aspect of the present invention may be the same as that of the eleventh aspect, in which the stimuli-responsive polymer gel and the costimuli-responsive polymer gel are laminated together.

[0191] According to the above configuration, the active ingredient is transferred between the stimuli-responsive polymer gel and the auxiliary stimuli-responsive polymer gel.

[0192] The impregnating material according to aspect 13 of the present invention may be the same as that according to aspect 11 above, wherein a plurality of the stimuli-responsive polymer gels and a plurality of the costimuli-responsive polymer gels are arranged to form a flat plate and are in contact with each other.

[0193] According to the above-mentioned configuration, the active ingredient is transferred between the stimuli-responsive polymer gel and the costimuli-responsive polymer gel. Furthermore, since the active ingredient can move relatively easily in the lateral direction in the flat stimuli-responsive polymer gel and the costimuli-responsive polymer gel, the active ingredient can be efficiently transferred between the stimuli-responsive polymer gel and the costimuli-responsive polymer gel.

[0194] In the impregnating material according to aspect 14 of the present invention, in the above-mentioned aspect 13, the joining surface where the stimuli-responsive polymer gel and the costimuli-responsive polymer gel are joined may be wider than the joining surface perpendicular to the surface formed by the joining of the stimuli-responsive polymer gel and the costimuli-responsive polymer gel.

[0195] According to the above configuration, it is possible to control and promote the movement of the active ingredient between the stimuli-responsive polymer gel and the co-stimuli-responsive polymer gel.

[0196] The impregnating material according to aspect 15 of the present invention may be the same as that according to aspect 13 above, except that a shielding polymer gel having a shielding property against the movement of moisture is provided between the stimuli-responsive polymer gels.

[0197] According to the above configuration, it is possible to control and suppress the movement of the active ingredient between the stimuli-responsive polymer gel and the costimuli-responsive polymer gel.

[0198] The impregnating material according to aspect 16 of the present invention is the same as that according to aspect 11 above, wherein the stimuli-responsive polymer gel and the costimuli-responsive polymer gel are each formed into particles and held in a permeable membrane that allows the active ingredient to pass through.

[0199] According to the above configuration, the particulate stimuli-responsive polymer gel and the costimuli-responsive polymer gel do not have a directional property in absorbing and releasing the active ingredient, which allows the active ingredient to be efficiently transferred between the stimuli-responsive polymer gel and the costimuli-responsive polymer gel.

[0200] A method for producing an impregnated material according to a seventeenth aspect of the present invention is a method for producing an impregnated material according to any one of the above-mentioned aspects 5 to 16, and includes a preparation step of preparing the stimuli-responsive polymer gel by crosslinking at least one of a stimuli-responsive polymer and a hydrophilic polymer, a drying step of drying the stimuli-responsive polymer gel to produce a dried body, and an absorption step of absorbing the active ingredient into the dried body.

[0201] Alternatively, the manufacturing method may include, instead of the drying step and the absorbing step, a mixing step of mixing the stimuli-responsive polymer constituting the stimuli-responsive polymer gel with the active ingredient to prepare a mixture, and a gelling step of gelling the mixture to prepare the stimuli-responsive polymer gel impregnated with the active ingredient.

[0202] A method for producing an impregnating material according to an eighteenth aspect of the present invention is a method for producing an impregnating material according to any one of the above-mentioned aspects 5 to 16, and includes a mixing step of mixing a stimuli-responsive polymer and a hydrophilic polymer with the active ingredient to prepare a mixture, and a gelling step of gelling the mixture by crosslinking both the stimuli-responsive polymer and the hydrophilic polymer in the mixture or by crosslinking one of the stimuli-responsive polymer and the hydrophilic polymer in the mixture, thereby preparing the stimuli-responsive polymer gel impregnated with the active ingredient in a dried or non-dried state.

[0203] A method for producing an impregnated material according to a nineteenth aspect of the present invention is a method for producing an impregnated material according to any one of the above-mentioned aspects 5 to 16, and includes a preparation step of preparing the stimuli-responsive polymer gel by crosslinking or mixing stimuli-responsive polymers, a mixing step of mixing the stimuli-responsive polymers that constitute the stimuli-responsive polymer gel with the active ingredient to prepare a mixture, and a gelling step of gelling the mixture to prepare the stimuli-responsive polymer gel impregnated with the active ingredient.

[0204] A method for producing an impregnated material according to aspect 20 of the present invention is a method for producing an impregnated material according to any one of aspects 5 to 16, and includes a mixing step of mixing a stimuli-responsive polymer with the active ingredient to prepare a mixture, and a gelling step of gelling the mixture by crosslinking the stimuli-responsive polymer in the mixture to prepare the stimuli-responsive polymer gel impregnated with the active ingredient.

[0205] The method for producing an impregnated material according to a twenty-first aspect of the present invention may be the method according to the nineteenth or twentyth aspect, further comprising a drying step of drying the stimuli-responsive polymer gel.

[0206] A method for producing an impregnated material according to aspect 22 of the present invention is a method for producing an impregnated material according to any one of aspects 5 to 16, and includes a preparation step of preparing the stimuli-responsive polymer gel by crosslinking or mixing stimuli-responsive polymers, a drying step of drying the stimuli-responsive polymer gel to produce a dried body, and an absorption step of absorbing the active ingredient into the dried body.

[0207] [Additional Notes] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

Claims

1. a first stimulus-responsive polymer gel containing a first stimulus-responsive polymer that exhibits hydrophobicity when the level of an external stimulus is less than a first level and exhibits hydrophilicity when the level of the external stimulus is equal to or greater than the first level; a second stimulus-responsive polymer gel containing a second stimulus-responsive polymer that exhibits hydrophilicity when the level of the external stimulus is less than a second level, and that exhibits hydrophobicity when the level of the external stimulus is equal to or higher than the second level, Polymer gel.

2. The first stimuli-responsive polymer gel further contains a first hydrophilic polymer. The polymer gel according to claim 1 .

3. The first stimuli-responsive polymer gel contains an active ingredient. The polymer gel according to claim 1 or 2.

4. The second stimuli-responsive polymer gel further contains a second hydrophilic polymer. The polymer gel according to any one of claims 1 to 3.

5. the second stimuli-responsive polymer gel contains an active ingredient; The polymer gel according to any one of claims 1 to 4.

6. The active ingredient is applied to the skin. The polymer gel according to claim 5 .

7. the first level and the second level are different from each other; The polymer gel according to any one of claims 1 to 6.

8. The first level is greater than the second level. The polymer gel according to claim 7 .

9. the first stimuli-responsive polymer gel and the second stimuli-responsive polymer gel are arranged side by side; The polymer gel according to any one of claims 1 to 8.

10. the first stimuli-responsive polymer gel and the second stimuli-responsive polymer gel are arranged so as to allow moisture transfer therebetween; The polymer gel according to any one of claims 1 to 9.

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