JP2012197344A - Adhesive hydrogel, production method thereof, composition for producing adhesive hydrogel, and gel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive hydrogel which hardly deteriorates repeating adhesiveness in addition to adhesive power, after dried, even when used for water washing and when immersed in water for a constant time.SOLUTION: The adhesive hydrogel wherein water and a polyhydric alcohol are contained in a polymer matrix, is characterized in that the polymer matrix is a copolymer of a crosslinking monomer with a polymerizable monomer mixture comprising (meth)acrylic acid, a derivative thereof or a 4-5C vinyl derivative having two carboxyl groups, an ionic (meth)acrylamide or a derivative thereof, and a specific nonionic (meth)acrylamide derivative, in specific amounts, respectively.

Description

  The present invention relates to an adhesive hydrogel and a method for producing the same, a composition for producing an adhesive hydrogel, and a gel sheet. More specifically, the present invention relates to an adhesive hydrogel that can be suitably used as a raw material for biomedical electrodes, medical adhesives, cosmetics, quasi drugs, industrial measurement electrodes, and the like, a method for producing the same, and a method for producing the same. The composition relates to a gel sheet containing the composition.

  Electrodes using a conductive polymer hydrogel in which a wetting agent and water are contained in a polymer matrix composed of polymerized and crosslinked polymers are used in various fields. For example, for biomedical electrodes, electrodes using a conductive polymer hydrogel containing a wetting agent and water in a polymer matrix obtained by polymerizing / crosslinking an electrolyte polymer such as polyacrylic acid have been used. . Electrodes using polymer hydrogels have a hydrophilic polymer matrix and are permeable to moisture, and at the same time contain water, making it easy to add electrolytes and lower impedance. It is. Therefore, it exhibits sufficient performance as an electrode for high precision measurement such as electrocardiogram monitoring.

  Once an electrode using such a conductive polymer hydrogel is applied to the object to be measured, sebum and stratum corneum on the skin surface are used for biomedical electrodes, and the object itself or surface dirt is stained for industrial electrodes. And the like are attached to the gel surface and the adhesive force is reduced, so that they are usually disposable. However, it is uneconomical to throw away after one-time use, and a reusable electrode is desired. However, it is difficult to prevent a decrease in adhesive strength in repeated use, and satisfactory reusability is difficult to obtain. . In addition, the polymer hydrogel has a problem that the polymer matrix is hydrophilic, and at the same time, the gel inclusion component is also hydrophilic, so that there is almost no water resistance when repeatedly washed with water or immersed in water for a certain period of time. there were.

  As a method for solving the above problem, a conventional method using a lipophilic gel, a silicone gel, a polyurethane or the like having a chemical structure with low hydrophilicity and resistant to washing with water can be considered. However, these materials have extremely low moisture permeability, and when they are used in a living body, fogging due to stuffiness may occur. In addition, since the amount of electrolyte that can be added to the gel is extremely small, it is not suitable for high-accuracy electrical measurements such as electrocardiogram monitoring and precision industrial measurement, in particular, where the gel alone has excellent conductivity. A technique for solving such a problem, that is, a gel electrode that can be washed with water is proposed in Japanese Patent Laid-Open No. 2001-406 (Patent Document 1). This gel electrode is a hydrogel containing water and a polyhydric alcohol, and at the same time is characterized in that the initial adhesive force can be recovered by washing the surface of the conductive polymer gel with water and removing dirt.

JP 2001-406 A

  However, although the gel electrode of Patent Document 1 can surely recover the initial adhesive strength, the adhesive strength gradually decreases with repeated use, and the repeated adhesiveness after washing with water is never satisfactory. It wasn't.

  It is an object of the present invention to provide an adhesive hydrogel that is less likely to reduce repeated adhesiveness in addition to adhesive strength after drying even when washed with water or immersed in water for a certain period of time.

  As a result of intensive studies to solve the above-mentioned problems, the inventor of the present invention has (meth) acrylic acid, a derivative thereof, or a vinyl derivative having 4 to 5 carbon atoms having two carboxyl groups and an ionic (meth). A hydrogel containing a polymer matrix comprising a copolymer of a polymerizable monomer mixture containing acrylamide or a derivative thereof and a specific nonionic (meth) acrylamide derivative and a crosslinkable monomer is washed with water. Has also been found to be excellent in adhesive strength and repeated adhesiveness, leading to the completion of the present invention.

Thus, according to the present invention, an adhesive hydrogel comprising water and a polyhydric alcohol in a polymer matrix,
The polymer matrix is composed of (meth) acrylic acid, a derivative thereof or a vinyl derivative having 4 to 5 carbon atoms having two carboxyl groups as component (A) and ionic (meth) acrylamide or component thereof as component (B). Derivatives and formula (1) as component (C):
_{^{CH 2 = CR 1 -CONR 2 R}} 3 (1)
(Wherein R ¹ is a hydrogen atom or a methyl group, and R ² and R ³ are a hydrogen atom or a lower alkyl group)
A copolymer of a polymerizable monomer mixture containing a nonionic (meth) acrylamide derivative represented by: and a crosslinkable monomer,
The component (A), the component (B), and the component C) are 5.0 to 20.0 parts by weight, 3.0 to 15.0 parts by weight, and 0. An adhesive hydrogel characterized by containing 3-3.0 parts by weight is provided.

Moreover, according to this invention, it is a manufacturing method of said adhesive hydrogel, Comprising: Said (A) component 5.0-20.0 weight part, Said (B) component 3.0-15.0 weight Part, a polymerizable monomer mixture containing 0.3 to 3.0 parts by weight of the component (C), a crosslinkable monomer, water, and a polyhydric alcohol are stirred and dissolved to prepare a monomer mixture solution Obtaining
A step of copolymerizing the polymerizable monomer mixture and the crosslinkable monomer by heating or ultraviolet irradiation of the obtained monomer compounded solution to obtain a polymer matrix, A method for producing an adhesive hydrogel comprising a matrix containing water and a polyhydric alcohol is provided.

  Furthermore, according to this invention, it is the composition for adhesive hydrogel manufacture used for manufacture of said adhesive hydrogel, Comprising: With respect to 100 weight part of said compositions for adhesive hydrogel manufacture, A) A polymerizable monomer mixture containing 5.0 to 20.0 parts by weight of component, 3.0 to 15.0 parts by weight of component (B) and 0.3 to 3.0 parts by weight of component (C). A composition for producing an adhesive hydrogel comprising a crosslinkable monomer, water and a polyhydric alcohol is provided.

  Furthermore, according to this invention, the gel sheet characterized by including the said adhesive hydrogel is provided.

  The adhesive hydrogel according to the present invention has excellent adhesive force after drying and excellent repeated adhesive force even when washed with water or immersed in water for a certain period of time. Therefore, products (such as electrode pads) using the hydrogel according to the present invention can withstand repeated use as compared with conventional products, so that the product life is long, economical, and resource saving is achieved. be able to.

  The adhesive hydrogel is an adhesive hydrogel further comprising polyvinylpyrrolidone or a derivative thereof as a component (D) in a polymer matrix, wherein the polyvinylpyrrolidone or a derivative thereof is 100 parts by weight of the adhesive hydrogel. When 0.1-6 weight part is contained with respect to this, the adhesive hydrogel which has the further outstanding adhesive force can be provided.

  When the polyhydric alcohol is selected from ethylene glycol, propylene glycol, butanediol, glycerin, pentaerythritol, sorbitol, polyethylene glycol, polypropylene glycol, polyglycerin, and polyoxyethylene glycerin A gel can be provided.

  (A) Component (meth) acrylic acid, derivatives thereof or vinyl derivatives having 4 to 5 carbon atoms having two carboxyl groups are (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, (poly ) Ethylene glycol (meth) acrylate, (poly) propylene glycol (meth) acrylate and (poly) glycerin (meth) acrylate, and (B) component (meth) acrylamide or a derivative thereof is tertiary butyl acrylamide sulfonic acid (TBAS) or a salt thereof, N, N-dimethylaminoethylacrylamide (DMAEAA) hydrochloride, N, N-dimethylaminopropylacrylamide (DMAPAA) hydrochloride, (meth) acrylamide, N-methyl (meth) acrylamide, N- Ethyl (meth) acrylamide, N, - dimethyl (meth) acrylamide, N, N-diethyl (meth) when selected from acrylamide and acryloyl morpholine can provide adhesive hydrogel having a more excellent adhesion.

  Moreover, when an adhesive hydrogel further contains 0.05-10 weight part electrolyte with respect to 100 weight part of adhesive hydrogel, the adhesive hydrogel excellent in electroconductivity can be provided.

The adhesive hydrogel according to the present invention (hereinafter also referred to as “hydrogel” or “gel”) comprises water and a polyhydric alcohol in a polymer matrix.
The constituent components of the adhesive hydrogel of the present invention will be described. In the following description, “adhesive hydrogel 100 parts by weight” means a polymerizable monomer, a crosslinkable monomer, water, a polyhydric alcohol, Means the total of the optional polyvinyl pyrrolidone and other additives.

(Polymer matrix)
The polymer matrix (hereinafter also referred to as “matrix”) is composed of (A) (meth) acrylic acid, a derivative thereof, or a vinyl derivative having 4 to 5 carbon atoms having two carboxyl groups, and (B) an ionic (meth) It is a copolymer of a polymerizable monomer mixture containing acrylamide or a derivative thereof and (C) a nonionic (meth) acrylamide derivative and a crosslinkable monomer. In addition, (meth) acryl means acryl or methacryl.
In the present invention, “ionic” means that a cation and an anion are generated when dissolved in water, and a 1% by weight aqueous solution of a monomer in a free acid state exhibits a pH of less than 4. It means that there is.

A polymer matrix is formed by polymerization and crosslinking of the polymerizable monomer and the crosslinkable monomer. The ratio of the polymer matrix contained in the adhesive hydrogel is preferably 8.5 to 44 parts by weight with respect to 100 parts by weight of the adhesive hydrogel. 10 to 42 parts by weight is more preferable, and 15 to 40 parts by weight is particularly preferable.
When the ratio of the polymer matrix is less than 8.5 parts by weight, the matrix concentration in the resulting gel is too low, and the matrix cannot easily hold the solvent and easily bleed, and the gel strength may be weakened. On the other hand, when the ratio of the polymer matrix exceeds 44 parts by weight, the heat generated during the polymerization of the monomer mixture forming the polymer matrix becomes excessively large, and the reaction runs out of control and boils above the boiling point of the solvent. There is. In addition, when boiling, air bubbles are mixed into the gel, so that a good gel may not be obtained.

(1) Polymerizable monomer mixture (M) acrylic acid of component (A) contained in the polymerizable monomer mixture, a derivative thereof or a vinyl derivative having 4 to 5 carbon atoms having two carboxyl groups, and (B ) Component (meth) acrylamide or a derivative thereof has good polymerization reactivity, and thus can reduce residual monomers. Moreover, the affinity with the other component in adhesive hydrogel is also favorable.

As component (A), (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, (poly) ethylene glycol (meth) acrylate, (poly) propylene glycol (meth) acrylate and (poly) glycerin ( And (meth) acrylate. These can be used alone or in combination of two or more.
Moreover, it is preferable that (A) component is water-soluble.
Here, (poly) ethylene means ethylene or polyethylene. Polyethylene means a structure having 2 to 10 ethylene units. (Poly) propylene and (poly) glycerin mean the same contents as (poly) ethylene.

  (A) A component is 5.0-20.0 weight part with respect to 100 weight part of adhesive hydrogels, Preferably 6.0-15.0 weight part is contained. If the amount contained is less than 5.0 parts by weight, the adhesive strength of the hydrogel may be reduced. On the other hand, if the amount contained exceeds 20.0 parts by weight, a large amount of residual monomer is generated, the post-treatment process becomes complicated, and the quality of the hydrogel obtained due to the influence of the residual monomer may be deteriorated.

As component (B), electrolytes such as tertiary butyl acrylamide sulfonic acid (TBAS) or a salt thereof, N, N-dimethylaminoethyl acrylamide (DMAEAA) hydrochloride, N, N-dimethylaminopropyl acrylamide (DMAPAA) hydrochloride And acrylamide derivatives. These can be used alone or in combination of two or more.
Moreover, it is preferable that (B) component is water-soluble.

  (B) A component is 3.0-15.0 weight part with respect to 100 weight part of adhesive hydrogel, Preferably 5.0-12.0 weight part is contained. If the amount contained is less than 3.0 parts by weight, a large amount of residual monomer may be generated. On the other hand, when the amount contained exceeds 15.0 parts by weight, the tackiness of the hydrogel may be lowered.

The component (C) is represented by the formula (1):
_{^{CH 2 = CR 1 -CONR 2 R}} 3 (1)
(Wherein R ¹ is a hydrogen atom or a methyl group, and R ² and R ³ are a hydrogen atom or a lower alkyl group)
It is represented by
The lower alkyl group of the substituents R ² and R ³ in the formula (1) is a straight chain having 3 to 6 carbon atoms such as propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, etc. Examples include branched lower alkyl groups. Among these, an isobutyl group, a sec-butyl group, and a tert-butyl group are particularly preferable.
When the number of carbon atoms is less than 3, the repeated adhesiveness after washing may be deteriorated. When the number of carbon atoms exceeds 6, the strength of the gel may be lowered or the transparency may be impaired.

  As the component (C) represented by the formula (1), N-propylacrylamide, N-isopropylacrylamide, N-butylacrylamide, N-isobutylacrylamide, N-sec-butylacrylamide, N-tert-butylacrylamide, N -Pentylacrylamide, N-hexylacrylamide, etc. are mentioned.

  Component (C) is contained in an amount of 0.3 to 3.0 parts by weight, preferably 0.4 to 2.0 parts by weight, based on 100 parts by weight of the adhesive hydrogel. If the amount contained is less than 0.3 part by weight, the repeated tackiness after washing with water may be deteriorated. On the other hand, when the amount contained exceeds 3.0 parts by weight, the strength of the gel may be reduced or the transparency may be impaired.

  In the present invention, in addition to the polymerizable monomer, (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N -Nonelectrolytic acrylamide derivatives such as diethyl (meth) acrylamide and acryloylmorpholine can be used as appropriate.

(2) Crosslinkable monomer As the crosslinkable monomer, one having two or more double bonds having polymerizability in the molecule is preferable. Specifically, methylene bis (meth) acrylamide [N, N′-methylene bisacrylamide], ethylene bis (meth) acrylamide, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, Examples include polyfunctional (meth) acrylamides such as glycerin di (meth) acrylate and glycerin tri (meth) acrylate or (meth) acrylate, tetraallyloxyethane, diallyl ammonium chloride, and the like. These can be used alone or in combination of two or more.

In addition, as the crosslinkable monomer, one or more polymerizable double bonds and 1 functional group having crosslinkable reactivity by elimination reaction or ring-opening reaction include epoxy group, hydroxyl group, alkoxy group, and the like. One or more glycidyl (meth) acrylates, N-methylol acrylamide and the like are also included.
Furthermore, in the case of performing crosslinking by ions, it is possible to give a part of the ionic polymerizable monomer a function as a crosslinkable monomer.

The ratio of the crosslinkable monomer in producing the polymer matrix varies depending on the polymerizable monomer species and the crosslinkable monomer species used, but is generally 0.01 to 100 parts by weight of the hydrogel. It is preferable that it is -0.5 weight part. More preferably, it is 0.03-0.25 weight part, More preferably, it is 0.05-0.2 weight part.
When the proportion of the crosslinkable monomer is less than 0.01 parts by weight, the crosslink density is low, the gel shape stability is poor, and the gel that is torn off when the gel applied to the skin is peeled off remains on the skin surface. There is. In addition, when used for electrical measurement, the measured value may easily vary due to thickness variation. On the other hand, when the ratio of the crosslinkable monomer exceeds 0.5 parts by weight, the gel tends to be hard and brittle with almost no adhesive force.

(Polyhydric alcohol)
Examples of the polyhydric alcohol contained in the adhesive hydrogel of the present invention include diols such as ethylene glycol, propylene glycol, and butanediol, polyhydric alcohols such as glycerin, pentaerythritol, and sorbitol, polyethylene glycol, polypropylene glycol, polyglycerin, and the like. And polyhydric alcohol modified products such as polyoxyethylene glycerin. These can be used alone or in combination of two or more.

  Among these polyhydric alcohols, a liquid is preferable in a temperature range where the adhesive hydrogel is actually used (for example, around 20 ° C. when used indoors). Examples of such polyhydric alcohols include ethylene glycol, propylene glycol, polyethylene glycol, polyglycerin, glycerin and the like.

It is preferable that the ratio of a polyhydric alcohol is 10-80 weight part with respect to 100 weight part of adhesive hydrogel. More preferably, it is 20-70 weight part.
If the ratio of the polyhydric alcohol is less than 10 parts by weight, the moisture retention power of the gel is poor, the transpiration of water becomes remarkable, the gel is not stable over time and lacks flexibility, and it is difficult to impart tackiness to the gel. May be. On the other hand, when the proportion of the polyhydric alcohol exceeds 80 parts by weight, the polyhydric alcohol may bleed on the surface of the gel and the adhesive strength may be reduced. Also, when preparing a blended solution of polyhydric alcohol, water and polyvinylpyrrolidone, the viscosity becomes too high, handling becomes worse and dissolution may be difficult. Furthermore, bubbles may be mixed when the gel is molded, and an extra defoaming process may be required.

(Polyvinylpyrrolidone)
The adhesive hydrogel according to the present invention preferably further comprises polyvinyl pyrrolidone or a derivative thereof in the polymer matrix in that the adhesive strength before washing with water is improved.
It is preferable that 0.1 to 6 parts by weight of polyvinyl pyrrolidone is contained with respect to 100 parts by weight of the hydrogel. More preferably, it is 0.2 to 3.0 parts by weight. When the content of polyvinyl pyrrolidone is less than 0.1 parts by weight, the effect of improving the adhesive strength may be small. On the other hand, when the amount exceeds 6 parts by weight, the viscosity of the liquid mixture at the time of gel preparation becomes too high, and the liquid mixture aggregates, making uniform dissolution difficult, and a uniform gel may not be obtained.

  The K value of polyvinylpyrrolidone is preferably 25 to 88. More preferably, it is 27-85. If the K value is less than 25, when the gel is applied to a living body and peeled off, the water-soluble polymer present in the vicinity of the gel surface may remain on the skin surface, and uncomfortable feeling may remain. In addition, when a water-soluble polymer emerges at the interface between the gel adhesive surface and the object to be adhered, adhesion may be hindered due to low molecular weight and lack of cohesiveness. On the other hand, if the K value exceeds 88, even if the amount of the water-soluble polymer to be added is a very small amount, the viscosity of the compounded liquid prepared when preparing the gel becomes too high, and uniform dissolution becomes difficult. A uniform gel may not be obtained.

The K value in the present invention is a value obtained by expressing the size of the molecular weight by the Fikenscher method, and can be obtained by the following measurement method.
When the K value is less than 20, the viscosity of a 5% (g / 100 ml) solution is measured, and when the K value is 20 or more, the viscosity of a 1% (g / 100 ml) solution is measured. Sample concentration is converted to dry matter. If the K value is 20 or more, 1.0 g of the sample is accurately measured, put into a 100 ml volumetric flask, add distilled water at room temperature, dissolve completely with shaking, add distilled water to make exactly 100 ml. To do. The sample solution is allowed to stand for 30 minutes in a thermostatic chamber (25 ± 0.2 ° C.) and then measured using an Ubbelohde viscometer. Measure the time for the solution to flow between the two markings. Measure several times and take the average value. In order to define the relative viscosity, the same is measured for distilled water. The two obtained flow times are corrected based on the Hagenbach-Couette correction value.
K value = [[300ClogZ + (C + 1.5ClogZ) 2] 1/2 + 1.5ClogZ-C]
/(0.15C+0.003C2) (1)
In the above formula (1), C represents the concentration of the sample (%: g / 100 ml), and Z represents the relative viscosity (ηrel) of the solution having the concentration C.
The relative viscosity ηrel is obtained from the following equation.
ηrel = (solution flow time) / (water flow time) (2)

(water)
The content of water contained in the adhesive hydrogel is not particularly limited, but 10 parts by weight with respect to 100 parts by weight of the adhesive hydrogel in order to optimize the adhesive properties and electrical properties finally obtained. To 50 parts by weight. More preferably, it is 10-45 weight part, More preferably, it is 20-30 weight part.
If the water content is less than 10 parts by weight, the water content with respect to the equilibrium water content of the gel is too small, so that the hygroscopicity becomes strong and the gel may deteriorate over time. On the other hand, when the water content exceeds 50 parts by weight, the difference from the equilibrium moisture content of the gel increases, and the gel may shrink due to drying or change in physical properties.

(Electrolytes)
The adhesive hydrogel may contain an electrolyte. By including an electrolyte, it is possible to obtain a conductive gel suitable for bioelectrode applications such as an electrocardiogram measurement electrode, a low-frequency treatment device electrode, and various earth electrodes. When used as such a bioelectrode application, the specific resistance of the adhesive hydrogel containing the electrolyte is preferably 0.1 to 10 kΩ · cm.

A salt is mentioned as electrolyte contained in the adhesive hydrogel in this invention.
Salts include sodium halide, potassium halide, magnesium halide, calcium halide, alkali metal halides, alkaline earth metal halides, other metal halides, various metals, hypochlorous acid, Chloric acid, chloric acid, perchlorate, sulfate, nitrate, phosphate, ammonium salts, inorganic salts such as various complex salts, monovalent organic carboxylates such as acetic acid, benzoic acid, lactic acid, tartaric acid, phthalates In addition to monovalent or divalent salts of polyvalent carboxylic acids such as acids, succinic acid, adipic acid and citric acid, metal salts of organic acids such as sulfonic acids and amino acids, and organic ammonium salts, poly (meth) Polymer electrolyte salts such as acrylic acid, polyvinyl sulfonic acid, polytertiary butyl acrylamide sulfonic acid, polyallylamine, and polyethyleneimine are listed. It is.

  The electrolyte may be insoluble during the preparation of the hydrogel, and may have a property of dissolving in the hydrogel over time, even if it is in a dispersed form during preparation of the mixture. Examples of such an electrolyte include silicates, aluminates, metal oxides, hydroxides, and the like.

  When the electroconductivity suitable for adhesive hydrogel is calculated | required, it is preferable that 0.05-10 weight part of electrolyte is contained with respect to 100 weight part of hydrogel. More preferably, it is 0.1 to 2 parts by weight. Hydrogel containing moisture originally has a characteristic as a dielectric, and has an electric capacity corresponding to the thickness of the gel and the area of the electrode element when the electrode is produced by combining with the electrode element. However, the impedance (Z) of the electrode is greatly influenced by the electrolyte concentration, particularly in the low frequency region below 1 kHz. When the content of the electrolyte is less than 0.05 parts by weight, the impedance becomes high and may not be suitable for conductive use. On the other hand, if it exceeds 10 parts by weight, it may be difficult to dissolve the electrolyte in the hydrogel, and crystal precipitation may occur inside the gel, or dissolution of other components may be hindered. In addition, the conductive performance reaches its peak, and it cannot be said that addition beyond this is beneficial from the viewpoint of imparting conductivity.

  The electrolyte may be used for purposes other than imparting conductivity to the hydrogel. For example, an acidic salt, a basic salt, or a polyfunctional salt may be added for the purpose of adjusting the pH of the hydrogel. In addition, an electrolyte may be added for the purpose of improving the moisture retention performance of the hydrogel and imparting antibacterial properties.

(Other additives)
The adhesive hydrogel has anti-inflammatory properties such as preservatives, bactericides, rust inhibitors, antioxidants, stabilizers, fragrances, surfactants, colorants and the like as long as they do not impair the effects of the present invention. You may add suitably other medicinal ingredients, such as an agent, a vitamin agent, and a whitening agent.
These additives can be used in an amount of 0.05 to 10 parts by weight based on 100 parts by weight of the hydrogel.

(Method for producing adhesive hydrogel)
As a method of obtaining the adhesive hydrogel of this invention, (A) component 5.0-20.0 weight part, (B) component 3.0-15.0 weight part, (C) component 0.3 A polymerizable monomer mixture containing ~ 3.0 parts by weight, a crosslinkable monomer, water, a polyhydric alcohol, and optionally 0.1 to 6 parts by weight of component (D) are stirred and dissolved. To obtain a monomer blending solution,
The step of obtaining a polymer matrix by copolymerizing the polymerizable monomer mixture and the crosslinkable monomer by heating or ultraviolet irradiation of the obtained monomer compounded solution is included. The monomer compounding liquid may contain a polymerization initiator as necessary.

  It can also be obtained by impregnating a polymer matrix previously formed by a polymerization reaction with water or a non-crosslinked water-soluble polymer. In addition, a crosslinkable monomer or catalyst is added to a polymer blend obtained by dissolving or uniformly dispersing a linear polymer obtained by polymerizing only a polymerizable monomer, water, a non-crosslinked water-soluble polymer, and the like. It can also be obtained by a method of adding and reacting a linear polymer with a crosslinkable monomer to form a matrix.

  As a polymerization method for obtaining the hydrogel, general radical polymerization, redox polymerization, radiation polymerization and the like are possible in addition to photopolymerization. Among the various polymerization methods described above, photopolymerization by light irradiation is preferred because the production process is simple and very economical, and at the same time it is possible to obtain a gel having stable physical properties.

In photopolymerization, it is preferable to polymerize by irradiating with ultraviolet rays in the presence of a photopolymerizable initiator. The cumulative irradiation amount of ultraviolet rays is preferably 1000 mJ / cm ² or more. If ^{2000mJ / cm 2 ~10000mJ / cm 2} , since the amount of residual monomer in the gel can be reduced to 100ppm or less, more preferably. When the cumulative irradiation amount of ultraviolet rays is less than 1000 mJ / cm ² , the polymerization reaction may not proceed sufficiently. If the cumulative amount of UV irradiation is too large, a large UV irradiation device is required and unnecessary energy is consumed. Furthermore, a separate process for removing the heat generated by ultraviolet irradiation is required, which may increase the manufacturing cost.

  The photopolymerizable initiator is not particularly limited as long as it is cleaved with ultraviolet rays or visible rays to generate radicals, and known ones can be used. Of these, α-hydroxyketone, α-aminoketone, benzylmethyl ketal, bisacylphosphine oxide, metallocene and the like are preferable.

  Specific examples of the photopolymerization initiator include 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-propan-1-one (product name: Irgacure 2959, Ciba Specialty Chemicals) 2-hydroxy-2-methyl-1-phenyl-propan-1-one (product name: Darocur 1173, manufactured by Ciba Specialty Chemicals), 1-hydroxy-cyclohexyl-phenyl-ketone (product name: Irgacure 184) , Manufactured by Ciba Specialty Chemicals), 2-methyl-1-[(methylthio) phenyl] -2-morpholinopropan-1-one (product name: Irgacure 907, manufactured by Ciba Specialty Chemicals), 2-benzyl- 2-Dimethylamino-1- (4-morpholinophenyl) -butane-1- Emissions (product name: Irgacure 369, manufactured by Ciba Specialty Chemicals), and the like. These can be used alone or in combination of two or more.

  The photopolymerization initiator is preferably added in an amount of 0.01 to 1 part by weight with respect to 100 parts by weight of the hydrogel in order to sufficiently perform the polymerization reaction and reduce the amount of residual monomer. More preferably, it is 0.05-0.5 weight part. When the addition amount of the photopolymerization initiator is less than 0.01 part by weight, the polymerization reaction may not proceed sufficiently. On the other hand, when the addition amount of the photopolymerization initiator exceeds 1 part by weight, the hydrogel may be discolored (yellowed) or smelled by the residue of the polymerization initiator after the polymerization reaction.

(Example of adhesive hydrogel molding method (gel sheet))
Since the adhesive hydrogel is gelled by polymerizing / crosslinking a liquid compounded liquid, it can be appropriately formed according to the intended use. For example, the said composition is dripped on base films, such as a resin film, and after dripping, a top film, such as a resin film, is spread on the upper surface, a composition is spread, and it controls to desired thickness. In this state, an adhesive hydrogel having a desired thickness can be obtained by polymerization and crosslinking by irradiation with light (ultraviolet rays) and / or heat.

  For example, when used as an adhesive, it may be formed into a gel sheet having a thickness of 0.01 mm to 2.0 mm. In that case, you may shape | mold into the gel sheet which provided the protective film in the single side | surface or both surfaces.

  The protective film for producing the gel sheet can be used as a separator or a support, and a known film may be used. Moreover, the preparation method of a gel sheet is not specifically limited, It can manufacture by a well-known method.

  As the base film, polyester, polyolefin, polystyrene, polyurethane, paper, paper laminated with a resin film, or the like can be used. The surface of the film that contacts the gel sheet is preferably subjected to a release treatment such as silicone coating.

  When the base film is used as a release paper, a film having a release treatment applied to the surface of a film such as polyester, polyolefin, polystyrene, paper, paper laminated with a resin film, or the like is preferably used. Biaxially stretched PET film, OPP and the like are particularly preferable. Examples of the mold release treatment method include a silicone coating, and a baking type silicone coating that is crosslinked and cured with heat or ultraviolet rays is particularly preferable.

  When the base film is used not as a release paper but as an adhesive packing material (backing material), it is preferable to use polyester, polyolefin, polystyrene, polyurethane or the like without releasing treatment. Of these, polyurethane films are particularly preferred because they are flexible and have water vapor permeability. In addition, since a polyurethane film is usually too soft and difficult to handle in the production process, it is preferable to laminate and use a polyolefin film or paper as a carrier film.

  It is preferable that a gel production | generation process is performed in the state which attached the carrier film to the base film. The top film may be basically made of the same material as the base film, but it is preferable to select a film that does not block light so as not to prevent photopolymerization. Moreover, it is preferable not to use the film used for the packing material (backing material) as the top film. In particular, when the film used for the packing material may be deteriorated by irradiation with ultraviolet rays or the like, it is not preferable because the film is located on the side directly irradiated with ultraviolet rays.

(Example of electrode pad using hydrogel and its manufacturing method)
Adhesive hydrogels have the property of adhering safely to the skin and the like. Moreover, electroconductivity can be easily provided by adding electrolyte arbitrarily. Therefore, it can be suitably used as an adhesive conductive part such as an electrode pad. An example of using the adhesive hydrogel of the present invention as an electrode pad will be described below.

  First, an adhesive hydrogel is laminated on one side of a conductive layer in which a conductive substance such as carbon is kneaded. Next, a non-conductive support is laminated on the surface opposite to the surface on which the hydrogel is laminated. A conductive material such as a copper wire is attached to the support so as to be in contact with the conductive layer, which serves as a terminal. Electricity can flow from the outside through the terminal to an external monitor or the like, and can become an adhesive conductive site where electricity can flow through the conductive layer and the hydrogel to the object to be applied.

  The conductive layer includes a carbon coat layer formed of a carbon paste using a polyester-based or polyurethane-based resin as a binder, a layer coated with a conductive ink containing a metal such as Ag / AgCl, carbon, etc., a metal foil on the resin film (Aluminum, stainless steel, Ag, etc.) or a layer laminated with a conductive film kneaded with carbon or the like is used. It is desirable for the conductive layer to have a strength that does not easily break when a force is applied from the outside, such as a tensile force. If it breaks easily, the conductive layer may be cut off during the production of the electrode, the electrode of the final product may be deformed due to stretching, and further, depending on the user's handling, the conductive layer in the electrode may break, causing burns, etc. There is a possibility of attracting. On the other hand, since it sticks to an uneven skin surface, flexibility is also required. It is necessary to select a conductive layer having physical properties that do not cause problems during use.

  In the case of a film in which a support and a conductive layer are laminated, the terminal is formed by providing a part of the film where the hydrogel is not laminated when laminating the adhesive hydrogel on the conductive layer. . Terminals (portions where no hydrogel is laminated) are sandwiched between clips and connected to lead wires.

  In the case of an electrode having a caulking structure, the electrode is not particularly limited as long as it has conductivity, but a snap terminal and a resin molded product in which a metal such as stainless steel or carbon is kneaded and a resin molded product are Ag / AgCl or the like. An element coated with metal, and the part of the sandwiched structure becomes a terminal and is connected to the outside.

  When using a metal wire, etc., the metal wire is partly sandwiched between the conductive layer and the support, and the portion that protrudes from the laminated portion of the conductive layer and the support is covered with a non-conductive resin or the like. The tip of the metal wire is connected to the outside by being connected to the lead wire.

(Evaluation of repeated adhesive strength after washing with water)
The gel sheet and electrode pad obtained using the adhesive hydrogel have excellent repeated adhesive force even when washed with water. Specifically, N1 is the initial adhesive strength after washing with water (the force required for first peeling after being applied to the object), and then the pasting and peeling are repeated until the 10th adhesive strength (10th adhesive strength) When the force required for peeling is N10, the relationship between N1 and N10 is
0.6 <N10 / N1 <1.0
It becomes. When N10 / N1 is smaller than 0.6, the adhesive strength is greatly reduced when it is repeatedly used, which is not preferable. More preferably, it exceeds 0.75, and particularly preferably exceeds 0.80.
As a method for washing with water, for example, after being immersed in water at 20 ° C. for 1 minute, it is dried in an atmosphere at 23 ° C. and a relative humidity of 60%.

  Since the adhesive hydrogel according to the present invention has excellent repeated adhesive force even when washed with water as described above, gel sheets and electrode pads obtained using this hydrogel are not found in conventional products. It has excellent repeated adhesive strength and can extend the product life. Therefore, it is expected to help save resources by reducing the frequency of single use.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to these. First, measurement methods and evaluation methods in Examples and Comparative Examples will be described.

(Measurement method of adhesive strength: Repeated adhesive strength of skin 180 °)
A sample cut into a 20 mm × 100 mm strip was immersed in water at 20 ° C. for 1 minute, dried for 120 minutes in an atmosphere of 23 ° C. and a relative humidity of 60%, and then backed with a nonwoven fabric. This test piece is affixed to the skin on the inner side of the left arm that has been lightly wiped with alcohol. Two minutes after sticking, using Tensilon (Orientec Co., Ltd.), the value of the force required to peel the test piece 180 ° at a rate of 1000 mm / min is defined as the initial adhesive strength (N1). . Then, the peeled test piece was affixed to the skin inside the left arm and peeled off repeatedly, and the value of the force required for the 10th peeling (counting from the first peeling) was determined as the adhesive strength (N10 ). And the numerical value which remove | divided N10 by N1 is made into the adhesive force retention rate with respect to initial stage adhesive force. The measurement conditions are an atmosphere with a temperature of 23 ° C. and a humidity of 60%.

Example 1
As a polymerizable monomer, acrylic acid 14.4 parts by weight, tertiary butyl acrylamide sulfonic acid 9.6 parts by weight and tertiary butyl acrylamide 0.6 parts by weight, polyvinyl pyrrolidone (Daiichi Kogyo Seiyaku Co., Ltd .: Crease K30, K value: 29.2) 5.4 parts by weight, N, N'-methylenebisacrylamide as a crosslinkable monomer 0.06 parts by weight, polyglycerin as a polyhydric alcohol (manufactured by Sakamoto Pharmaceutical Co., Ltd .: polyglycerin # 310) , Average molecular weight 310) 44 parts by weight, 0.5 parts by weight of sodium chloride as an electrolyte, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-propane-1 as an ultraviolet polymerization initiator -On (product name: Irgacure 2959, manufactured by Ciba Specialty Chemicals) 0.2 parts by weight was stirred and dissolved. To prepare a monomer liquid combination Te.

Thereafter, the blended solution was adjusted to pH 4.0 to 5.0 with a 50 wt% NaOH aqueous solution to prepare ion exchange water so that the total amount of the adhesive hydrogel was 100 parts by weight (use of ion exchange water). Amount 17.24 parts by weight). Next, the obtained monomer blend solution was irradiated with ultraviolet rays having an energy amount of 3000 mJ / cm ² using a metal halide lamp to obtain a sheet-like adhesive hydrogel having a thickness of 0.75 mm. This hydrogel after water washing had an initial adhesive strength N1 (N) of 0.8, a repeated adhesive strength N10 (N) of 0.64, and an adhesive strength retention N10 / N1 of 0.8.

(Example 2)
5.4 parts by weight of polyvinylpyrrolidone (Daiichi Kogyo Seiyaku Co., Ltd .: CLEASURE K30, K value: 29.2) was 1.0 part by weight, and 17.24 parts by weight of ion-exchanged water was 21.64 parts by weight. Except for this, an adhesive hydrogel was obtained in the same manner as in Example 1. The initial adhesive strength N1 of this hydrogel after washing with water was 0.65, the repeated adhesive strength N10 (N) was 0.42, and the adhesive strength retention N10 / N1 was 0.65.

(Example 3)
Polyvinylpyrrolidone (Daiichi Kogyo Seiyaku Co., Ltd .: CLEASURE K30, K value: 29.2) 5.4 parts by weight was changed to 0 parts by weight, and ion-exchanged water 17.24 parts by weight was changed to 22.64 parts by weight. Produced an adhesive hydrogel in the same manner as in Example 1. The initial adhesive strength N1 of this hydrogel after washing with water was 0.85, the repeated adhesive strength N10 was 0.70, and the adhesive strength retention N10 / N1 was 0.82.

Example 4
Tertiary butylacrylamide 0.6 parts by weight, 1.2 parts by weight polyvinyl pyrrolidone (Daiichi Kogyo Seiyaku Co., Ltd .: Cleanse K30, K value: 29.2) 5.4 parts by weight, 0 parts by weight An adhesive hydrogel was obtained in the same manner as in Example 1 except that 17.24 parts by weight of the exchange water was changed to 22.04 parts by weight. The initial adhesive strength N1 of this hydrogel after washing with water was 0.83, the repeated adhesive strength N10 was 0.71, and the adhesive strength retention N10 / N1 was 0.85.

(Comparative Example 1)
0.6 parts by weight of tertiary butyl acrylamide is 0.1 parts by weight, 5.4 parts by weight of polyvinyl pyrrolidone (Daiichi Kogyo Seiyaku Co., Ltd .: Cleanus K30, K value: 29.2) is 0 parts by weight An adhesive hydrogel was obtained in the same manner as in Example 1 except that ion-exchanged water was prepared so that the total amount of the functional hydrogel was 100 parts by weight (amount of ion-exchanged water used was 23.14 parts by weight). The initial adhesive strength N1 (N) of this hydrogel was 0.7, the repeated adhesive strength N10 (N) was 0.07, and the adhesive strength retention N10 / N1 was 0.1.

(Comparative Example 2)
Except that 0.6 part by weight of tertiary butyl acrylamide was changed to 6 parts by weight, and 5.4 parts by weight of polyvinylpyrrolidone (Daiichi Kogyo Seiyaku Co., Ltd .: CLEASURE K30, K value: 29.2) was changed to 0 part by weight. Although an attempt was made to produce an adhesive hydrogel in the same manner as in Example 1, tertiary butyl acrylamide did not dissolve and a uniform blended solution could not be produced.

According to Table 1, (meth) acrylic acid, a derivative thereof, or a vinyl derivative having 4 to 5 carbon atoms having two carboxyl groups, ionic (meth) acrylamide or a derivative thereof, nonionic as a polymerizable monomer It can be seen that the adhesive hydrogel in which the (meth) acrylamide derivative is produced within the scope of the present invention has excellent repeated adhesiveness in addition to adhesive force.
Moreover, it turns out that the adhesive hydrogel produced using polyvinyl pyrrolidone within the scope of the present invention as the polymerizable monomer has further excellent repeated adhesiveness.

Claims (8)

An adhesive hydrogel comprising water and a polyhydric alcohol in a polymer matrix,
The polymer matrix is composed of (meth) acrylic acid, a derivative thereof or a vinyl derivative having 4 to 5 carbon atoms having two carboxyl groups as component (A) and ionic (meth) acrylamide or component thereof as component (B). Derivatives and formula (1) as component (C):
_{^{CH 2 = CR 1 -CONR 2 R}} 3 (1)
(Wherein R ¹ is a hydrogen atom or a methyl group, and R ² and R ³ are a hydrogen atom or a lower alkyl group)
A copolymer of a polymerizable monomer mixture containing a nonionic (meth) acrylamide derivative represented by: and a crosslinkable monomer,
The component (A), the component (B), and the component C) are 5.0 to 20.0 parts by weight, 3.0 to 15.0 parts by weight, and 0. An adhesive hydrogel comprising 3 to 3.0 parts by weight.   The adhesive hydrogel is an adhesive hydrogel in which polyvinyl pyrrolidone or a derivative thereof is further contained as the component (D) in the polymer matrix, and the component (D) is 100 weights of the adhesive hydrogel. The pressure-sensitive adhesive hydrogel according to claim 1, which is contained in an amount of 0.1 to 6 parts by weight.   The tacky hydro of claim 1 or 2, wherein the polyhydric alcohol is selected from ethylene glycol, propylene glycol, butanediol, glycerin, pentaerythritol, sorbitol, polyethylene glycol, polypropylene glycol, polyglycerin and polyoxyethylene glycerin. gel.   The component (A) is (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, (poly) ethylene glycol (meth) acrylate, (poly) propylene glycol (meth) acrylate and (poly) glycerin ( Selected from (meth) acrylate, and the component (B) is tert-butylacrylamide sulfonic acid (TBAS) or a salt thereof, N, N-dimethylaminoethylacrylamide (DMAEAA) hydrochloride, N, N-dimethylaminopropylacrylamide ( DMAPAA) hydrochloride, (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide and acryloylmorpholine Billed According to any one of 1 to 3 the adhesive hydrogel.   The adhesive hydrogel according to any one of claims 1 to 4, wherein the adhesive hydrogel further comprises 0.05 to 10 parts by weight of electrolyte with respect to 100 parts by weight of the adhesive hydrogel. It is a manufacturing method of the adhesive hydrogel as described in any one of Claims 1-5, Comprising: The said (A) component 5.0-20.0 weight part, The said (B) component 3.0-15 0.0 parts by weight, a polymerizable monomer mixture containing 0.3 to 3.0 parts by weight of the component (C), a crosslinkable monomer, water, and a polyhydric alcohol are stirred and dissolved. Obtaining a monomer blending solution;
A step of copolymerizing the polymerizable monomer mixture and the crosslinkable monomer by heating or ultraviolet irradiation of the obtained monomer compounded solution to obtain a polymer matrix, A method for producing an adhesive hydrogel comprising water and a polyhydric alcohol in a matrix.   It is a composition for adhesive hydrogel manufacture used for manufacture of the adhesive hydrogel as described in any one of Claims 1-5, Comprising: With respect to 100 weight part of said compositions for adhesive hydrogel manufacture Polymerization comprising 5.0 to 20.0 parts by weight of component (A), 3.0 to 15.0 parts by weight of component (B), and 0.3 to 3.0 parts by weight of component (C) A composition for producing an adhesive hydrogel comprising an adhesive monomer mixture, a crosslinkable monomer, water and a polyhydric alcohol.   A gel sheet comprising the adhesive hydrogel according to any one of claims 1 to 5.