JP2018051155A - Conductive laminated hydrogel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive hydrogel sheet, even when a direct current is applied thereto for a fixed time, capable of substantially suppressing increase in pH and/or decrease in conductivity.SOLUTION: The present invention relates to a conductive laminated hydrogel sheet 101 formed by alternately laminating a hydrogel sheet A layer 11a with a film thickness of a mm and a hydrogel sheet B layer 12a with a film thickness of b mm. The hydrogel sheet A layer 11a includes at least one type of inorganic salt with a total content of X wt.% with respect to the total weight of the hydrogel sheet A layer 11a, and the hydrogel sheet B layer 12a includes at least one type of inorganic salt with a total content of Y wt.% with respect to the total weight of the hydrogel sheet B layer 12a, where Y is less than X. The hydrogel sheet B layer 12a includes at least two hydrogel sheet layers including at least one type of acid.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a conductive laminated hydrogel sheet.

  The hydrogel having adhesiveness is suitably used as an adhesive hydrogel sheet that constitutes a transdermally absorbable preparation or a cosmetic pack to be attached to a living body. Moreover, since hydrogel can provide electroconductivity by containing electrolytes, such as an inorganic salt, it is suitable also as an adhesive electroconductive hydrogel sheet which comprises electrode pads, such as a living body or an industrial measurement. It is used for. Biological electrode pads having an adhesive conductive hydrogel sheet are various, such as biomedical measuring devices that measure bioelectricity such as electrocardiograms, and bioelectrical therapeutic devices that apply a voltage to a living body to obtain a therapeutic effect. Used in medical equipment.

  For example, Patent Document 1 is characterized by using a polymer matrix obtained by polymerizing a polymer matrix-forming material, an adhesive hydrogel containing water and a polyhydric alcohol, and the adhesive hydrogel. The electrode pad to be described is described.

  BACKGROUND ART A bioelectric treatment device for applying a current to a living body has been conventionally used for applying an alternating current or a pulsed current. On the other hand, in recent years, a bioelectric treatment device for applying a direct current has been developed (Patent Documents 2 and 3). By applying a direct current to a living body, it is said that the activities of intracellular organelles such as cells or mitochondria can be efficiently activated compared to the case where an alternating current is applied to the living body (Patent Literature). 3).

Japanese Patent No. 5844594 Japanese Patent Laid-Open No. 11-235387 JP 2013-202194 A

  Since the hydrogel sheet has both adhesiveness and conductivity, it is used as a constituent member of an electrode pad in various biological or industrial measurement equipment. However, there have been some problems when applying hydrogel sheets to electrode pads in certain devices. For example, in a device such as a bioelectric therapy device, when a direct current is applied to an adherend for a certain period of time using an electrode pad including a conventional hydrogel sheet, electrolysis may occur inside the hydrogel sheet. In this case, on the negative electrode side of the hydrogel sheet, the pH may increase with the generation of hydroxide ions. In addition, on the positive electrode side of the hydrogel sheet, bubbles may be generated as oxygen is generated, and conductivity may be reduced. When the content of an electrolyte, for example, an inorganic salt in the hydrogel sheet is reduced in order to suppress the progress of electrolysis, the conductivity of the hydrogel sheet may be reduced. On the other hand, if the content of the inorganic salt in the hydrogel sheet is increased in order to improve conductivity, the progress of electrolysis may be promoted.

  Therefore, an object of the present invention is to provide a conductive hydrogel sheet that can substantially suppress an increase in pH and / or a decrease in conductivity even when a direct current is applied for a certain period of time.

  The present inventors have studied various means for solving the above problems. The inventors of the present invention produced a conductive laminated hydrogel sheet having at least two hydrogel sheet layers by alternately laminating two hydrogel sheet layers having different inorganic salt contents within a predetermined range. In the conductive laminated hydrogel sheet having such a configuration, the inventors have arranged a conductive hydrogel sheet layer containing a large amount of inorganic salt on the positive electrode side, and less than that contained in the conductive hydrogel sheet layer. When a conductive hydrogel sheet layer containing a quantity of inorganic salt and at least one acid is arranged on the negative electrode side and a direct current is applied for a certain period of time, the increase in pH and the decrease in conductivity are substantially suppressed. I found it. Based on the above findings, the present inventors have completed the present invention.

That is, the gist of the present invention is as follows.
(1) A hydrogel sheet A layer having a thickness of a mm and a hydrogel sheet B layer having a thickness of b mm are alternately laminated,
The hydrogel sheet A layer contains at least one inorganic salt having a total content X wt% based on the total weight of the hydrogel sheet A layer, and the hydrogel sheet B layer has a total content Y with respect to the total weight of the hydrogel sheet B layer. % By weight of at least one inorganic salt, provided that Y is less than X;
The hydrogel sheet B layer contains at least one acid,
A conductive laminated hydrogel sheet having at least two hydrogel sheet layers.
(2) The conductive laminated hydrogel sheet according to the embodiment (1), wherein at least one acid includes an organic acid.
(3) X and Y are the following formula (1):
0 ≦ Y <X ≦ 15 (1)
The conductive laminated hydrogel sheet according to the embodiment (1) or (2), which satisfies the above.
(4) When the water content of the hydrogel sheet B layer is α% by weight with respect to the total weight of the hydrogel sheet B layer, Y and α are the following formula (2):
0 ≦ Y / α ≦ 0.03 (2)
The conductive laminated hydrogel sheet according to any one of the embodiments (1) to (3), which satisfies the above.
(5) a and b are the following formulas (3) and (4):
b / a ≧ 1 (3)
0.6 ≦ a + b ≦ 3.0 (4)
The conductive laminated hydrogel sheet according to any one of the embodiments (1) to (4), which satisfies the above.
(6) A membrane selected from the group consisting of a semipermeable membrane, an ion exchange membrane, a microfiltration membrane, an ultrafiltration membrane, and a nanofiltration membrane is further disposed between the hydrogel sheet A layer and the hydrogel sheet B layer. The conductive laminated hydrogel sheet according to any one of the embodiments (1) to (5).
(7) The conductive laminated hydrogel sheet according to any one of the embodiments (1) to (6), and an electrode electrically connected to the hydrogel sheet A layer or the hydrogel sheet B layer of the conductive laminated hydrogel sheet; Having an electrode pad.
(8) The conductive laminated hydrogel sheet according to any one of the embodiments (1) to (6), and an electrode electrically connected to the hydrogel sheet A layer or the hydrogel sheet B layer of the conductive laminated hydrogel sheet; A living body electrode pad in which a hydrogel sheet A layer or a hydrogel sheet B layer, which is not connected to an electrode of a conductive laminated hydrogel sheet, is used as a contact portion with a living body.
(9) The living body electrode pad according to the embodiment (8), and a power supply unit electrically connected to the electrode of the electrode pad, the hydrogel sheet A layer of the living body electrode pad is on the positive electrode side, An electrotherapeutic device for living body, in which a hydrogel sheet B layer is disposed on the negative electrode side.
(10) The biological electrode pad according to the embodiment (8), which is used for applying a direct current.
(11) The biological electrotherapy device according to the embodiment (9), which is used for applying a direct current.

According to the present invention, it is possible to provide a conductive hydrogel sheet that can substantially suppress an increase in pH and / or a decrease in conductivity even when a direct current is applied for a certain period of time.
Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

FIG. 1 is a cross-sectional view illustrating an embodiment of a conductive laminated hydrogel sheet according to an aspect of the present invention. FIG. 2 is a cross-sectional view showing another embodiment of the conductive laminated hydrogel sheet according to one aspect of the present invention. FIG. 3 is a cross-sectional view showing another embodiment of the conductive laminated hydrogel sheet according to one aspect of the present invention. FIG. 4 is a cross-sectional view showing another embodiment of the conductive laminated hydrogel sheet according to one aspect of the present invention. FIG. 5 is a cross-sectional view illustrating an embodiment of an electrode pad using the conductive laminated hydrogel sheet according to one aspect of the present invention. FIG. 6 is a cross-sectional view illustrating another embodiment of the electrode pad using the conductive laminated hydrogel sheet according to one aspect of the present invention. FIG. 7 is a cross-sectional view illustrating another embodiment of the electrode pad using the conductive laminated hydrogel sheet according to one aspect of the present invention. FIG. 8 is a cross-sectional view illustrating another embodiment of the electrode pad using the conductive laminated hydrogel sheet according to one aspect of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail.
One embodiment of the present invention relates to a conductive laminated hydrogel sheet having at least two hydrogel sheet layers. One embodiment of a conductive laminated hydrogel sheet according to one aspect of the present invention is shown in FIGS.

  As shown in FIG. 1, a conductive laminated hydrogel sheet 101 according to this embodiment has at least two hydrogel sheet layers, a hydrogel sheet A layer 11 and a hydrogel sheet B layer 12. In the conductive laminated hydrogel sheet 101 according to this embodiment, the hydrogel sheet A layer 11 and the hydrogel sheet B layer 12 are alternately laminated by disposing the hydrogel sheet A layer 11 on the upper surface of the hydrogel sheet B layer 12. Arranged so that.

  In the conductive laminated hydrogel sheet according to this embodiment, when two or more hydrogel sheets A and B are present, the two or more hydrogel sheets A are within the scope of the characteristics disclosed in the present specification. Thus, they may have the same size and / or composition, and may have different sizes and / or compositions. Further, the two or more hydrogel sheet B layers may have the same dimensions and / or compositions within the features disclosed in the present specification, and may have different dimensions and / or compositions. May be.

  In the conductive laminated hydrogel sheet according to this embodiment, the hydrogel sheet A layer contains at least one inorganic salt having a predetermined content. Further, the hydrogel sheet B layer contains at least one inorganic salt having a predetermined content or no inorganic salt. When the hydrogel sheet A layer contains at least one inorganic salt having a predetermined content, the conductive laminated hydrogel sheet according to this embodiment can have conductivity as a whole.

  X weight% of the total content of at least one inorganic salt contained in the hydrogel sheet A layer relative to the total weight of the hydrogel sheet A layer, at least contained in the hydrogel sheet B layer relative to the total weight of the hydrogel sheet B layer Y is less than X when the total content of one inorganic salt is Y wt%. That is, the total content Y of at least one inorganic salt contained in the hydrogel sheet B layer is less than the total content X of at least one inorganic salt contained in the hydrogel sheet A layer. In the conductive laminated hydrogel sheet according to this embodiment in which Y is less than X, the present inventors have arranged the hydrogel sheet A layer on the positive electrode side and contain at least one acid described below. It has been found that when the B layer is disposed on the negative electrode side and a direct current is applied for a certain period of time, an increase in pH and a decrease in conductivity are substantially suppressed. Such an effect is obtained in the conductive laminated hydrogel sheet according to this embodiment, in the hydrogel sheet B layer containing a small amount of inorganic salt or not containing an inorganic salt, the progress of electrolysis is substantially suppressed, and the pH is reduced. It is considered that the conductivity is substantially maintained by containing a large amount of inorganic salt in the hydrogel sheet A layer while the rise and generation of bubbles are substantially suppressed. Therefore, when the conductive laminated hydrogel sheet according to this embodiment is applied to, for example, an electrode pad and various devices using the electrode pad, even if a direct current is applied for a certain period of time, the increase in pH and the decrease in conductivity are substantially reduced. Therefore, the electrode pad and the device can be used stably.

In the conductive laminated hydrogel sheet according to this embodiment, X and Y are the following formula (1):
0 ≦ Y <X ≦ 15 (1)
It is preferable to satisfy. The total content of at least one inorganic salt contained in the hydrogel sheet B layer may be 0 or more. That is, the hydrogel sheet B layer may not contain an inorganic salt. On the other hand, since the total content of at least one inorganic salt contained in the hydrogel sheet A layer is in a range exceeding 0, the conductive laminated hydrogel sheet according to this embodiment may have conductivity as a whole. it can. When Y is in a range exceeding X, in the conductive laminated hydrogel sheet according to this embodiment, when the hydrogel sheet A layer is disposed on the positive electrode side and a direct current is applied for a certain period of time, electrolysis proceeds in the hydrogel sheet B layer, An increase in pH and / or generation of bubbles may occur. X is preferably in the range of 2 to 15% by weight, more preferably in the range of 2 to 8% by weight. Y is less than X, preferably in the range of 0 or more and less than 15% by weight, more preferably in the range of 0 or more and less than 8% by weight. When X is less than 2% by weight, there is a possibility that sufficient conductivity cannot be expressed. Moreover, when X exceeds 15% by weight, there is a possibility that a sufficient effect cannot be obtained even if the content of the inorganic salt is increased. Therefore, when X and Y satisfy Equation (1), the conductive laminated hydrogel sheet according to this embodiment substantially suppresses the increase in pH and the decrease in conductivity even when a direct current is applied for a certain period of time. be able to.

  As the at least one inorganic salt contained in the hydrogel sheet A layer and the hydrogel sheet B layer, for example, halogen such as sodium halide (for example, sodium chloride), lithium halide, and potassium halide is not limited. Alkali metal halides; Halogenated alkaline earth metals such as magnesium halide and calcium halide; and other metal halides. In addition, hypochlorite, chlorite, chlorate, perchlorate, sulfate, carbonate, nitrate, or phosphate of various metals can be suitably used as the inorganic salt. Alternatively, inorganic salts such as ammonium salts or various complex salts can be suitably used as the inorganic salts. As the at least one inorganic salt contained in the hydrogel sheet A layer and the hydrogel sheet B layer, these inorganic salts may be used alone, or two or more inorganic salts may be used in combination.

  In the conductive laminated hydrogel sheet according to this embodiment, the kind and total content of at least one inorganic salt contained in the hydrogel sheet A layer, and the kind of at least one inorganic salt contained in the hydrogel sheet B layer and The total content is not limited, but, for example, a sample of the hydrogel sheet A layer or the hydrogel sheet B layer having a predetermined weight is taken out, and at least one inorganic salt contained in the sample is extracted by ICP emission spectroscopy. It can be determined by quantification using an analysis means such as analysis, atomic absorption analysis or ion chromatography.

  In the conductive laminated hydrogel sheet according to this embodiment, the hydrogel sheet B layer contains at least one acid. The at least one acid can include organic and inorganic acids, and mixtures thereof. The at least one acid preferably includes an organic acid, and more preferably is an organic acid. Organic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, capric acid, phthalic acid, oxalic acid, lactic acid, tartaric acid, fumaric acid, maleic acid, succinic acid, citric acid, malic acid , Glutaric acid, adipic acid, amino acids, ascorbic acid, benzoic acid, salicylic acid and polyacrylic acid. The at least one acid contained in the hydrogel sheet B layer is preferably 10% by weight or less, more preferably in the range of 0.01 to 10% by weight, based on the total weight of the hydrogel sheet B layer. More preferably, it is in the range of ˜2% by weight. When the hydrogel sheet B layer contains at least one acid, the pH of the hydrogel sheet B layer can be adjusted to the above preferable range. Thereby, the electroconductive laminated hydrogel sheet which concerns on this aspect can suppress the raise of pH substantially even if a direct current is applied for a fixed time.

  The hydrogel sheet A layer may contain a weakly basic substance such as chitosan, a weakly basic amino acid, or a cationic polymer for the purpose of suppressing fluctuations in pH.

  In the conductive laminated hydrogel sheet according to this embodiment, the kind and content of at least one acid contained in the hydrogel sheet A layer, and the kind and content of at least one acid contained in the hydrogel sheet B layer are: Although not limited, for example, a sample of the hydrogel sheet A layer or the hydrogel sheet B layer having a predetermined weight is taken out, and at least one acid contained in the sample is analyzed by high performance liquid chromatography in the case of an organic acid. Analysis such as chromatography (HPLC), gas chromatography (GC), liquid chromatography / mass spectrometry (LC / MS), ion chromatography / mass spectrometry (IC / MS) or gas chromatography / mass spectrometry (GC / MS) In the case of inorganic acids, the determination is made by quantifying using an analytical means such as ICP emission spectrometry, atomic absorption analysis, or ion chromatography. Can be determined.

  In the conductive laminated hydrogel sheet according to this embodiment, various hydrogels known in the technical field can be applied to the hydrogel constituting the hydrogel sheet A layer and the hydrogel sheet B layer. In the present specification, “hydrogel” means a swollen body in a gel form including a polymer matrix having a three-dimensional network structure and water molecules present in the network structure. The hydrogel usually includes a polymer matrix, water, and a polyhydric alcohol.

  The polymer matrix constituting the hydrogel is not limited. For example, it may be formed from a copolymer of a monofunctional monomer having one ethylenically unsaturated group and a crosslinkable monomer. Can do.

  The monofunctional monomer is preferably a water-soluble monomer such as a (meth) acrylamide monomer or a (meth) acrylic ester. In the present specification, “(meth) acryl” means acryl or methacryl, and “(meth) acrylate” means acrylate or methacrylate.

  Specific examples of (meth) acrylamide monomers include N, N-dialkyl (meth) acrylamides such as (meth) acrylamide, N, N-dimethyl (meth) acrylamide and N, N-diethyl (meth) acrylamide; N-alkyl (meth) acrylamides such as N-isopropyl (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide and N-propyl (meth) acrylamide; N-hydroxyethyl (meth) acrylamide and N-hydroxyalkyl (meth) acrylamides such as N-hydroxymethyl (meth) acrylamide; N-ethoxymethyl (meth) acrylamide, N-propoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-isobutoxy Methyl (meth) acrylamide, N-pentoxymethyl ( T) acrylamide, N-hexyloxymethyl (meth) acrylamide, N-heptoxymethyl (meth) acrylamide, N-octoxymethyl (meth) acrylamide, N-ethoxyethyl (meth) acrylamide, N-propoxyethyl (meth) acrylamide and N-alkoxyalkyl (meth) acrylamides such as N-butoxyethyl (meth) acrylamide; amino group-containing cationic acrylamide compounds such as dimethylaminopropyl (meth) acrylamide; 4-acryloylmorpholine and tert-butylacrylamide sulfonic acid And sulfonic acid group-containing anionic monofunctional monomers or salts thereof; and derivatives thereof. (Meth) acrylamide monomers include, but are not limited to, (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide , N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide 4-acryloylmorpholine and tert-butylacrylamidesulfonic acid, and at least one compound selected from the group consisting of salts thereof are preferred.

  Specific examples of (meth) acrylic acid esters include (meth) acrylic acid alkyl esters having an alkyl group having 1 to 18 carbon atoms, such as methyl (meth) acrylate, ethyl (meth) acrylate, and (meth) acrylic. N-propyl acid, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, (meth) acrylic N-octyl acid, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-pentyl (meth) acrylate, (meth) acrylic N-decyl acid, isodecyl (meth) acrylate, n-lauryl (meth) acrylate, tridecyl (meth) acrylate and n- (meth) acrylate (Meth) acrylic acid alkyl esters such as stearyl; alicyclic (meth) acrylic esters such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate and 1-adamantyl (meth) acrylate; (meth) acrylic acid Alkoxy group-containing (meth) acrylic acid esters such as 2-methoxyethyl, (meth) acrylic acid ethoxyethoxyethyl and (meth) acrylic acid methoxytriethylene glycol and the like (meth) acrylic acid methoxypolyethylene glycol; (meth) acrylic acid Such as 2-hydroxyethyl, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate and 2-hydroxybutyl (meth) acrylate (through an ether bond to the hydroxyalkyl group Aryl group may be bonded) (meta Hydroxyalkyl acrylate; mono (meth) acrylic acid glycerin; mono (meth) acrylic acid polyethylene glycol and polyethylene glycol-polypropylene glycol copolymer and other mono (meth) acrylic acid polyalkylene glycols; (meth) acrylic acid benzyl, etc. (Meth) acrylic acid ester having an aromatic ring; and (meth) acrylic acid ester having a heterocyclic ring such as tetrahydrofurfuryl (meth) acrylate.

  In addition to the (meth) acrylamide monomer exemplified above, the monofunctional monomer may include (meth) acrylic acid or a salt thereof, (meth) acrylic acid ester, vinylpyrrolidone, vinylacetamide, if necessary. Alternatively, a vinylamide monofunctional monomer such as vinylformamide; a nonionic monofunctional monomer such as allyl alcohol; or a styrene monomer can be used. These monofunctional monomers may be used alone or in combination of two or more monomers.

  In the hydrogel constituting the hydrogel sheet A layer and the hydrogel sheet B layer, the content of the structural unit derived from the monofunctional monomer is not limited, but is 10 weights with respect to 100 parts by weight of the hydrogel. The range is preferably from 50 parts by weight to 50 parts by weight, and more preferably from 10 parts by weight to 35 parts by weight. When the content of the structural unit derived from the monofunctional monomer is less than the lower limit value, the shape retention of the hydrogel becomes insufficient, which may be too soft or easy to tear. Moreover, when content of the structural unit derived from the said monofunctional monomer exceeds the said upper limit, hydrogel becomes hard and a softness | flexibility may be impaired. Therefore, when the content of the structural unit derived from the monofunctional monomer is within the above range, it can maintain a predetermined shape and have a predetermined flexibility.

  As the crosslinkable monomer, a monomer having two or more double bonds having a polymerizable property in the molecule is preferable. Specific examples of the crosslinkable monomer include methylene bis (meth) acrylamide, ethylene bis (meth) acrylamide, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, and glycerin di (meth). And polyfunctional (meth) acrylamides such as acrylate and glycerol tri (meth) acrylate or (meth) acrylate, tetraallyloxyethane, and diallylammonium chloride. These crosslinkable monomers may be used alone or in combination of two or more monomers. Alternatively, as a crosslinkable monomer having two or more double bonds having a polymerizable property in the molecule, it has two or more (meth) acryloyl groups or vinyl groups described in Japanese Patent No. 2803886, and Polyglycerin derivatives which are polyfunctional compounds having a molecular weight of 400 or more can also be used.

  In the hydrogel constituting the hydrogel sheet A layer and the hydrogel sheet B layer, the amount of the crosslinkable monomer is preferably in the range of 0.0005 to 0.5 parts by weight, and 0.001 to 0.2 parts by weight with respect to 100 parts by weight of the hydrogel. The range is more preferably in the range of 0.001 to 0.1 parts by weight. When the addition amount of the crosslinkable monomer is less than the lower limit, the crosslink density becomes low and the shape stability becomes poor. At the same time, the cohesive force is lowered, the holding power of the hydrogel itself is lowered, and the adhesive strength is reduced. May be low. Moreover, after making it contact with the adherend of a living body (for example, skin), a part of the hydrogel may remain on the adherend when it is peeled off from the adherend. In this case, the handleability of the conductive laminated hydrogel sheet according to this embodiment may be deteriorated. Moreover, when the addition amount of the said crosslinkable monomer exceeds the said upper limit, adhesive force may become weak and it may become a hard and brittle gel. The polymer matrix in the above definition means a matrix formed by polymerizing and crosslinking the monofunctional monomer and the crosslinkable monomer.

  In the hydrogel constituting the hydrogel sheet A layer and the hydrogel sheet B layer, the water content is not limited, but is preferably in the range of 10 to 60 parts by weight with respect to 100 parts by weight of the hydrogel. 15 to 50 parts by weight is more preferable, and 15 to 40 parts by weight is particularly preferable. When the water content is less than the lower limit, the water content relative to the equilibrium water content of the hydrogel decreases, the hygroscopicity of the hydrogel increases, and the hydrogel may deteriorate (eg, swell) over time. There is. Further, when the water content exceeds the upper limit, the water content with respect to the equilibrium water content of the hydrogel increases, and there is a possibility that the hydrogel shrinks or changes in physical properties due to drying. Therefore, when the water content is within the above range, physical property changes such as moisture absorption or shrinkage of the hydrogel can be substantially suppressed.

In the conductive laminated hydrogel sheet according to this embodiment, when the water content of the hydrogel sheet B layer is α% by weight relative to the total weight of the hydrogel sheet B layer, Y and α are the following formula (2):
0 ≦ Y / α ≦ 0.03 (2)
It is preferable to satisfy. Y / α is preferably 0.02 or less, and more preferably 0.01 or less. When Y / α exceeds 0.03, in the conductive laminated hydrogel sheet according to this embodiment, when the hydrogel sheet A layer is disposed on the positive electrode side and a direct current is applied for a certain period of time, electrolysis proceeds in the hydrogel sheet B layer, An increase in pH and / or generation of bubbles may occur. Therefore, when Y and α satisfy the above formula (2), the conductive laminated hydrogel sheet according to this embodiment substantially suppresses the increase in pH and the decrease in conductivity even when a direct current is applied for a certain period of time. can do.

  In the conductive laminated hydrogel sheet according to this embodiment, the content of water contained in the hydrogel sheet A layer and the content of water contained in the hydrogel sheet B layer are not limited. Take a sample of the hydrogel sheet A layer or hydrogel sheet B layer of the weight, dry the sample and measure the dry weight, calculate the difference between the initial weight and the dry weight, or Karl Fischer moisture measuring device Can be determined by measuring by volumetric titration method or coulometric titration method.

  Polyhydric alcohols include, but are not limited to, for example, diols such as ethylene glycol, triethylene glycol, 1,6-hexanediol, 1,9-nonanediol, propylene glycol and butanediol; glycerin, pentaerythritol and Examples include trihydric or higher polyhydric alcohols such as sorbitol; polyhydric alcohol condensates such as polyethylene glycol, polypropylene glycol and polyglycerin; and polyhydric alcohol modified products such as polyoxyethylene glycerin. Among the polyhydric alcohols, it is preferable to use a polyhydric alcohol that is liquid in the temperature range of use of the hydrogel (for example, around 20 ° C. when used indoors). As the polyhydric alcohol, for example, ethylene glycol, triethylene glycol, propylene glycol, polypropylene glycol, polyethylene glycol, polyglycerin or glycerin is preferable.

  In the hydrogel constituting the hydrogel sheet A layer and the hydrogel sheet B layer, the content of the polyhydric alcohol is not limited, but within a range of 20 to 70 parts by weight with respect to 100 parts by weight of the hydrogel. It is preferable that it is within a range of 20 to 65 parts by weight. When the content of the polyhydric alcohol is less than the lower limit value, the resulting hydrogel has poor moisturizing power and plasticity, and the transpiration of water becomes significant, and the hydrogel lacks stability over time and lacks flexibility. There is a possibility that sufficient tackiness cannot be obtained. In addition, when the content of the polyhydric alcohol exceeds the upper limit, the amount of polyhydric alcohol that can be held by the polymer matrix is exceeded, and physical property fluctuations due to bleeding out of the polyhydric alcohol from the surface of the hydrogel. It may occur and sufficient tackiness may not be obtained. Therefore, when the content of the polyhydric alcohol is within the above range, it is possible to substantially suppress changes in physical properties such as a decrease in the viscosity of the hydrogel or physical properties such as bleeding out of the polyhydric alcohol. .

  In the conductive laminated hydrogel sheet according to this embodiment, the pH of the hydrogel sheet A layer and the hydrogel sheet B layer is usually in the range of weakly acidic to neutral, for example, 3 to 8. The pH of the hydrogel sheet A layer is preferably in the range of 3 to 8, and more preferably in the range of 4 to 7. The pH of the hydrogel sheet B layer is preferably in the range of 3 to 8, and more preferably in the range of 4 to 7. When the pH of the hydrogel sheet A layer and the hydrogel sheet B layer, particularly the hydrogel sheet B layer is in the above range, the conductive laminated hydrogel sheet according to this embodiment substantially increases the pH even when a direct current is applied for a certain period of time. Can be suppressed.

  In the conductive laminated hydrogel sheet according to this embodiment, the hydrogel sheet A layer and the hydrogel sheet B layer may contain other additives as desired. Examples of other additives include buffering agents, rust preventives, anticorrosives, antioxidants, antifoaming agents, stabilizers, surfactants, and coloring agents. Other additives are preferably buffers such as organic electrolyte salts. When the hydrogel sheet A layer and / or the hydrogel sheet B layer contains a buffering agent, the buffering ability can be imparted to the hydrogel sheet A layer and / or the hydrogel sheet B layer. When the hydrogel sheet A layer and the hydrogel sheet B layer contain other additives, various properties can be imparted to the conductive laminated hydrogel sheet according to this embodiment.

In the conductive laminated hydrogel sheet according to this embodiment, when the film thickness of the hydrogel sheet A layer is a mm and the film thickness of the hydrogel sheet B layer is b mm, a and b are the following formulas (3) and (4) :
b / a ≧ 1 (3)
0.6 ≦ a + b ≦ 3.0 (4)
It is preferable to satisfy. When b / a is less than 1 or a + b is less than 0.6, in the conductive laminated hydrogel sheet according to this embodiment, when the hydrogel sheet A layer is disposed on the positive electrode side and a direct current is applied for a certain period of time, Electrolysis proceeds in the gel sheet B layer, which may increase pH and / or generate bubbles. Moreover, when a + b exceeds 3.0, the remarkable effect according to a film thickness may not be acquired. Furthermore, for example, when the conductive laminated hydrogel sheet according to this aspect is applied to an electrode pad, workability may be reduced. Therefore, when a and b satisfy the above formulas (2) and (3), the conductive laminated hydrogel sheet according to this embodiment does not increase the pH and decrease the conductivity even when a direct current is applied for a certain period of time. It can be substantially suppressed. In addition, although the film thickness of the hydrogel sheet A layer and the hydrogel sheet B layer is not limited, it can be determined, for example, by measuring using a micrometer or the like. Further, when the top film and / or base film described below is disposed on the outer surface of the hydrogel sheet A layer and the hydrogel sheet B layer, the top film and / or the base film is removed, and the hydrogel sheet is removed by the above means. What is necessary is just to measure the film thickness of A layer and a hydrogel sheet B layer.

  In the conductive laminated hydrogel sheet according to this embodiment, the number of the hydrogel sheet A layer and the hydrogel sheet B layer may be one or more, respectively, and the upper limit is not particularly limited. The numbers of the hydrogel sheet A layer and the hydrogel sheet B layer are, for example, in the range of 1 to 3 layers, respectively. For example, as shown in FIG. 2, the conductive laminated hydrogel sheet 101 according to this embodiment has a total of six layers including three hydrogel sheets A layers 11a, 11b, and 11c and three hydrogel sheets B layers 12a, 12b, and 12c. The hydrogel sheet layer can be provided. In the case of this embodiment, the hydrogel sheet A layer 11a is disposed on the upper surface of the hydrogel sheet B layer 12a, the hydrogel sheet B layer 12b is disposed on the upper surface of the hydrogel sheet A layer 11a, and the hydrogel sheet is disposed on the upper surface of the hydrogel sheet B layer 12b. The A layer 11b is disposed, the hydrogel sheet B layer 12c is disposed on the upper surface of the hydrogel sheet A layer 11b, and the hydrogel sheet A layer 11c is disposed on the upper surface of the hydrogel sheet B layer 12c. 11b, 11c and hydrogel sheet B layers 12a, 12b, 12c can be arranged to be alternately stacked.

  Another embodiment of the conductive laminated hydrogel sheet according to this aspect is shown in FIGS. As shown in FIG. 3, in the conductive laminated hydrogel sheet 101 according to this embodiment, it is preferable that a film 13 is further disposed between the hydrogel sheet A layer 11 and the hydrogel sheet B layer 12. When the conductive laminated hydrogel sheet according to this embodiment has two or more layers of hydrogel sheet A and two or more layers of hydrogel sheet B, the membrane is disposed between the respective hydrogel sheet A layer and hydrogel sheet B layer. It is preferable. For example, as shown in FIG. 4, the conductive laminated hydrogel sheet 101 according to this embodiment has a total of six layers including three hydrogel sheets A layers 11a, 11b, 11c and three hydrogel sheets B layers 12a, 12b, 12c. The membranes 13a, 13b, 13c, 13ab, 13bc are further arranged between the respective hydrogel sheets A layers 11a, 11b, 11c and the three hydrogel sheets B layers 12a, 12b, 12c. be able to. In the case of this embodiment, the hydrogel sheet A layer 11a is disposed on the upper surface of the hydrogel sheet B layer 12a, the hydrogel sheet B layer 12b is disposed on the upper surface of the hydrogel sheet A layer 11a, and the hydrogel sheet is disposed on the upper surface of the hydrogel sheet B layer 12b. The A layer 11b is disposed, the hydrogel sheet B layer 12c is disposed on the upper surface of the hydrogel sheet A layer 11b, and the hydrogel sheet A layer 11c is disposed on the upper surface of the hydrogel sheet B layer 12c. 11b, 11c and hydrogel sheet B layers 12a, 12b, 12c are alternately laminated, and further, a membrane 13a is formed between the hydrogel sheet A layer 11a and the hydrogel sheet B layer 12a, and the hydrogel sheet A layer 11b and the hydrogel sheet B A membrane 13b is formed between the layer 12b and a membrane 13c is formed between the hydrogel sheet A layer 11c and the hydrogel sheet B layer 12c. Film 13ab between the gel sheet B layer 12b is, film 13bc between the hydrogel sheet A layer 11b and the hydrogel sheet B layer 12c is, may be disposed.

  The membrane is usually selected from the group consisting of a semipermeable membrane, an ion exchange membrane, a microfiltration membrane, an ultrafiltration membrane and a nanofiltration membrane. The membrane is not limited, but is preferably selected from the group consisting of cellophane, semipermeable membranes such as cellulose acetate, and ion exchange membranes such as cation exchange membranes and anion exchange membranes. Alternatively, an anion exchange membrane or the like is more preferable, and cellophane is further preferable. In the case of this embodiment, the mass transfer between the hydrogel sheet A layer and the hydrogel sheet B layer is substantially suppressed by the membrane. Therefore, in the case of the conductive laminated hydrogel sheet according to this embodiment, the effect of suppressing the increase in pH and the decrease in conductivity can be expressed over a longer period.

  The surface area of the membrane is preferably 80% or more of the surface area of the hydrogel sheet A layer in the laminated surface of the hydrogel sheet A layer and the hydrogel sheet B layer on which the membrane is disposed, more preferably 90% or more, substantially More preferably, it is 100%. When the surface area of the membrane is in the above range, mass transfer between the hydrogel sheet A layer and the hydrogel sheet B layer is substantially suppressed. Therefore, in the case of the conductive laminated hydrogel sheet according to this embodiment, the effect of suppressing the increase in pH and the decrease in conductivity can be expressed over a longer period.

  In the conductive laminated hydrogel sheet according to this embodiment, the hydrogel sheet A layer and / or the hydrogel sheet B layer may have an intermediate base material as desired. The intermediate base material is used in the technical field for the purpose of reinforcing the hydrogel sheet and / or improving the shape retention during cutting. An intermediate base material can be comprised from a nonwoven fabric or a woven fabric, for example. The material of the intermediate substrate can be appropriately selected from those usually used as an intermediate substrate for hydrogel in the technical field. Examples of the material of the nonwoven fabric or woven fabric used as the intermediate substrate include natural fibers such as cellulose, silk and hemp, synthetic fibers such as polyester, nylon, rayon, polyethylene, polypropylene and polyurethane, and blends thereof. be able to. The intermediate substrate can contain a binder as necessary. The intermediate substrate can be colored as necessary. When the hydrogel sheet A layer and / or the hydrogel sheet B layer has the intermediate base material, the strength and / or shape retention at the time of cutting of the conductive laminated hydrogel sheet according to this embodiment can be improved.

  In the conductive laminated hydrogel sheet according to this embodiment, a top film can be disposed on the outer surface of the hydrogel sheet A layer as desired. A base film can be disposed on the outer surface of the hydrogel sheet B layer as desired. The top film and the base film are preferably arranged so as to cover the entire outer surface of the hydrogel sheet A layer or the hydrogel sheet B layer. In the conductive laminated hydrogel sheet according to this aspect, by arranging the top film and the base film, the outer surfaces of the hydrogel sheet A layer and the hydrogel sheet B layer can be protected from contamination and / or drying until use. it can.

  As the base film, for example, a resin film made of a resin such as polyester, polyolefin, polystyrene, or polyurethane, paper, paper laminated with the resin film, or the like can be used. In the base film, it is preferable that the surface on the side in contact with the outer surface of the hydrogel sheet B layer is subjected to release treatment. Examples of the mold release treatment method include silicone coating. As a method for the mold release treatment, a baking type silicone coating which is crosslinked and cured with heat or ultraviolet rays is particularly preferable. As the base film subjected to the mold release treatment, a biaxially stretched polyethylene terephthalate (PET) film, a stretched polypropylene (OPP) film, or the like is particularly preferable.

  As the top film, the same material as the base film exemplified above can be applied. For example, when a top film is placed on the outer surface of the hydrogel sheet A layer and the monomers constituting the hydrogel sheet are polymerized by irradiating ultraviolet rays from above the top film, top the film of a material that does not block light. It is preferable to select as a film. By using the top film made of such a material, the polymerization of the monomer can be completed without hindering the photopolymerization.

In the conductive laminated hydrogel sheet according to this embodiment, a method for polymerizing the monomer is not particularly limited, and examples thereof include redox polymerization, radical polymerization, and radiation polymerization. In the case of radical polymerization, the hydrogel sheet A layer and the hydrogel sheet B layer are prepared by dissolving or uniformly dispersing each of the above materials containing a monomer and a polymerization initiator in a solvent or the like. In addition, a material containing a monomer can be polymerized and crosslinked by heating or ultraviolet irradiation. The polymerization initiator may be either a photopolymerization initiator or a thermal polymerization initiator. For example, in the case of a sheet having a film thickness of several millimeters to several micrometers, radical polymerization by ultraviolet light using a photopolymerization initiator. Is preferred. Examples of the photopolymerization initiator include 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl- 1-propan-1-one, 22-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, 1-hydroxy -Cyclohexyl-phenyl-ketone, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, phenylglyoxy Mention may be made of ric acid methyl ester, 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], and triarylsulfonium hexafluorophosphate. Examples of the thermal polymerization initiator include azobisisobutyronitrile and benzoyl peroxide. Further, the content of the polymerization initiator is not limited, but for example, it may be 0.01 parts by weight or more with respect to 100 parts by weight of the monomer compounded liquid before polymerization excluding the polymerization initiator. The amount is preferably 1 part by weight or less. In the case of polymerization by ultraviolet irradiation, the cumulative irradiation amount of ultraviolet rays varies depending on the content of the polymerization initiator, but is preferably in the range of 1,000 mJ / cm ^{2 to} 10,000 mJ / cm ² , for example, 2,000 mJ More preferably, it is in the range of / cm ^{2 to} 10,000 mJ / cm ² . By the said method, the electroconductive lamination | stacking hydrogel sheet which concerns on this aspect which has the hydrogel sheet A layer provided with a desired property and the hydrogel sheet B layer can be obtained.

  Another embodiment of the present invention is an electrode having a conductive laminated hydrogel sheet according to one embodiment of the present invention and an electrode electrically connected to the hydrogel sheet A layer or the hydrogel sheet B layer of the conductive laminated hydrogel sheet. Related to pads. The electrode pad according to the present embodiment can be used for various devices, for example, medical devices such as biological measuring devices or biological electrotherapeutic devices, measuring devices for surface inspection of ground or rock, water leakage sheets of waste disposal sites, etc. The present invention can be applied to an electrode portion of an industrial measurement device such as a damage detection device. In the electrode pad according to this aspect, a preferred embodiment is a biological electrode pad that can be applied to a medical device such as a biological measuring device or a biological electrotherapy device.

  The electrode pad according to this aspect is preferably for application of a direct current. As already described, the conductive laminated hydrogel sheet according to one embodiment of the present invention can substantially suppress an increase in pH and a decrease in conductivity even when a direct current is applied for a certain period of time. Therefore, the electrode pad according to this aspect can be used stably for a long period of time for applying a direct current.

  One embodiment of the electrode pad according to this aspect is shown in FIGS. As shown in FIGS. 5 and 6, the electrode pad 301 according to this embodiment includes a conductive laminated hydrogel sheet 101 according to one embodiment of the present invention, and a hydrogel sheet A layer 11 or a hydrogel sheet B layer 12 of the conductive laminated hydrogel sheet. And an electrode 21 electrically connected to the electrode 21. 5A and 6A show an electrode pad according to this embodiment having a conductive laminated hydrogel sheet 101 according to one embodiment of the present invention and an electrode 21 electrically connected to the hydrogel sheet A layer 11 of the conductive laminated hydrogel sheet. FIGS. 5B and 6B show an embodiment of 301, comprising a conductive laminated hydrogel sheet 101 according to one aspect of the present invention, and an electrode 21 electrically connected to the hydrogel sheet B layer 12 of the conductive laminated hydrogel sheet. One embodiment of each of the electrode pads 301 according to this aspect is shown. The electrode pad 301 according to this embodiment is usually disposed so as to be in close contact with the surface S of the adherend. In the electrode pad 301 according to this embodiment, the hydrogel sheet A layer 11 or the hydrogel sheet B layer 12 that is not connected to the electrode 21 of the conductive laminated hydrogel sheet 101 is used as a contact portion to the surface S of the adherend. . Since the hydrogel sheet A layer 11 and the hydrogel sheet B layer 12 have adhesiveness and flexibility, the electrode pad 301 according to this embodiment is provided via the outer surface of the hydrogel sheet A layer 11 or the hydrogel sheet B layer 12, Adherence can be achieved along the shape of the surface S of the adherend.

  Further, as shown in FIGS. 7 and 8, the electrode pad 301 according to this embodiment is arranged so as to be laminated on the surface of the electrode 21 and the electrode 21 arranged on the surface of the support base material 14 described below. The conductive laminated hydrogel sheet 101 according to one embodiment of the present invention may be included.

  For example, when the electrode pad 301 according to this aspect is an embodiment of a biological electrode pad, the surface S of the adherend is preferably a part of a living body such as skin. As already described, the conductive laminated hydrogel sheet 101 according to one embodiment of the present invention can substantially suppress an increase in pH and a decrease in conductivity even when a direct current is applied for a certain period of time. Therefore, the electrode pad 301 according to this embodiment can be used stably over a long period of time for applying a direct current without substantially affecting the surface S of the adherend.

  In the electrode pad 301 according to this embodiment, it is preferable to further dispose the support base material 14 on the outer surface of the hydrogel sheet A layer 11 or the hydrogel sheet B layer 12 as desired. The support substrate 14 is preferably arranged so as to cover the entire outer surface of the hydrogel sheet A layer 11 or the hydrogel sheet B layer 12. In the electrode pad 301 according to this embodiment, by disposing the support base material 14, the outer surface of the hydrogel sheet A layer 11 or the hydrogel sheet B layer 12 is insulated, and the hydrogel sheet A layer 11 or the hydrogel sheet B layer 12 The outer surface can be protected from contamination and / or drying.

  As the support substrate 14, a general insulating resin can be used. The support substrate 14 is preferably a film, foam, nonwoven fabric, rubber or the like containing polyester, polyethylene, polypropylene, polyvinyl chloride, PET, polyurethane, silicone, or the like.

For example, in the embodiment shown in FIGS. 5 and 6, the support base material 14 is excellent in workability and / or moisture permeability, and has good adhesion to the conductive laminated hydrogel sheet 101. A woven fabric or a non-woven fabric is preferred. In the present embodiment, the support base material 14 is particularly preferably a polyolefin non-woven fabric produced by a spunbond method. Although the thickness of the support base material 14 is not specifically limited, For example, it is the range of 0.2-1.2 mm. When the thickness of the support base material 14 is less than 0.2 mm, the support base material 14 becomes soft and the shape retention of the electrode pad 301 may be impaired. Further, when the thickness of the support substrate 14 exceeds 1.2 mm, the support substrate 14 becomes too thick, and the electrode pad 301 cannot be formed in a compact manner, and the handleability may be impaired. The basis weight of the support substrate 14 is not particularly limited, but is, for example, in the range of 50 to 110 g / m ² . When the basis weight of the support base material 14 is less than 50 g / m ² , the support base material 14 becomes soft and the shape retention of the electrode pad 301 may be impaired. Further, when the basis weight of the support base material 14 exceeds 110 g / m ² , the flexibility of the support base material 14 may be impaired, and the handleability of the electrode pad 301 may be impaired.

  For example, in the embodiment shown in FIGS. 7 and 8, the support substrate 14 is preferably a resin film that is flexible, has no stretchability, and has a relatively high waist strength. Examples of such a resin film include resin films such as PET, polyvinyl chloride, polyethylene, and polypropylene. In the present embodiment, the support substrate 14 is preferably the resin film having a thickness of 10 to 500 μm. The support substrate 14 is particularly preferably a PET film having high waist strength and easy printing.

  The electrode 21 can be usually obtained using a predetermined conductive material. As such a conductive substance, for example, a metal such as nickel, molybdenum, stainless steel, silver or platinum, a metal mixture such as silver or silver-silver chloride, carbon black or graphite, and the like alone or in combination of two or more kinds A conductive paste prepared by mixing the materials can be given. The electrode 21 can be obtained, for example, by printing a conductive paste on the surface of the support substrate 14 described above to form a conductive layer of the electrode. Alternatively, the electrode 21 can also be obtained by laminating the support substrate 14 described above and a film containing a metal foil such as silver, aluminum or tin or the conductive material described above.

  Another aspect of the present invention relates to a biological electrotherapy device including the biological electrode pad according to one aspect of the present invention and a power supply unit electrically connected to an electrode of the biological electrode pad. In the biological electrotherapy device according to this aspect, the hydrogel sheet A layer of the biological electrode pad is usually disposed on the positive electrode side, and the hydrogel sheet B layer is disposed on the negative electrode side.

  The biological electrotherapy device according to this embodiment is preferably for application of a direct current. As already described, the conductive laminated hydrogel sheet according to one embodiment of the present invention can substantially suppress an increase in pH and a decrease in conductivity even when a direct current is applied for a certain period of time. Therefore, the bioelectric therapy device according to this aspect can be used stably for a long period of time for applying a direct current.

  As described above in detail, the conductive laminated hydrogel sheet according to one aspect of the present invention can substantially suppress an increase in pH and a decrease in conductivity even when a direct current is applied for a certain period of time. . Therefore, the conductive laminated hydrogel sheet according to one embodiment of the present invention can be applied to various devices, for example, medical devices such as biological measuring devices or biological electrotherapy devices, or measuring devices for surface inspection of ground or rock. By applying these devices as components of electrode pads used in the electrode parts of industrial measurement equipment such as equipment for detecting breakage of water leakage sheets at waste disposal sites, etc., especially for application of direct current It can be used stably over a long period of time.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the technical scope of the present invention is not limited to these examples.

<I: Production of conductive hydrogel sheet>
[Production Example 1: Production of hydrogel sheet containing a large amount of inorganic salt]
Weigh 20 parts by weight of acrylamide, 0.03 part by weight of N, N-methylenebisacrylamide, 5 parts by weight of sodium chloride, 28 parts by weight of ion-exchanged water, 1 part by weight of citric acid and 2 parts by weight of trisodium citrate, and add glycerin. The mixture was obtained with 100 parts by weight as a whole. To 100 parts by weight of this mixed solution, 0.13 part by weight of 2-hydroxy-2-methyl-1-phenyl-propan-1-one (trade name: Irgacure 1173) is added as a photopolymerization initiator, mixed and dissolved. As a result, a monomer mixture was obtained. Next, a 0.3 mm thick silicone rubber sheet was cut out to produce a mold having a space of 120 mm × 120 mm. A small amount of ion-exchanged water was dropped on a 150 mm square glass substrate, and a 100 μm thick PET film coated with silicone and cut to 150 mm square was adhered and adhered. On the upper surface of the PET film, the previously formed silicone rubber sheet mold was placed. A monomer compounding solution was dropped into this frame. Further, the upper surface was covered with a 40 μm thick silicone-coated PET film cut into 150 mm square. A glass substrate was placed on the upper surface of the PET film and fixed with a clip. This was irradiated with ultraviolet rays using an ultraviolet irradiation device (JATEC, JU-C1500, metal halide lamp, conveyor speed 0.4 m / min, total irradiation energy 3,000 mJ / cm ² ). The monomer is polymerized by ultraviolet irradiation, contains 5% by weight sodium chloride as an inorganic salt, 1% by weight citric acid as an acid, and 28% by weight based on the total weight of the conductive hydrogel sheet. A conductive hydrogel sheet having a film thickness of 0.3 mm containing the above water was obtained.

[Production Example 2: Production of hydrogel sheet containing no inorganic salt]
In Production Example 1, except that the amount of sodium chloride in the monomer compounding solution was changed to 0 part by weight, and the thickness of the silicone rubber sheet mold was changed to 0.6 mm, the same procedure as in Production Example 1, A conductive hydrogel sheet having a thickness of 0.6 mm containing 1% by weight citric acid as an acid and 28% by weight water but not containing sodium chloride as an inorganic salt with respect to the total weight of the conductive hydrogel sheet Obtained.

[Production Example 3: Production of hydrogel sheet containing no inorganic salt]
In Production Example 1, the same procedure as in Production Example 1 except that the amount of sodium chloride in the monomer compounding solution was changed to 0 parts by weight and the thickness of the silicone rubber sheet mold was changed to 0.9 mm. A conductive hydrogel sheet having a thickness of 0.9 mm containing 1% by weight citric acid as an acid and 28% by weight water but not containing sodium chloride as an inorganic salt with respect to the total weight of the conductive hydrogel sheet. Obtained.

[Production Example 4: Production of hydrogel sheet containing no inorganic salt]
In Production Example 1, except that the amount of sodium chloride in the monomer mixture was changed to 0 parts by weight, the procedure was the same as in Production Example 1, and 1% by weight as an acid with respect to the total weight of the conductive hydrogel sheet Thus, a conductive hydrogel sheet having a film thickness of 0.3 mm containing citric acid and 28% by weight of water but not containing sodium chloride as an inorganic salt was obtained.

[Production Example 5: Production of hydrogel sheet containing a large amount of inorganic salt]
In Production Example 1, except that the thickness of the silicone rubber sheet mold was changed to 0.6 mm, the same procedure as in Production Example 1 was followed, and 5% by weight of chloride as an inorganic salt with respect to the total weight of the conductive hydrogel sheet. A conductive hydrogel sheet having a thickness of 0.6 mm containing sodium, 1% by weight of citric acid as an acid, and 28% by weight of water was obtained.

[Production Example 6: Production of hydrogel sheet containing a large amount of inorganic salt]
In Production Example 1, except that the thickness of the silicone rubber sheet mold was changed to 0.9 mm, the same procedure as in Production Example 1 was followed, except that 5% by weight of chloride as an inorganic salt with respect to the total weight of the conductive hydrogel sheet. A conductive hydrogel sheet having a thickness of 0.9 mm containing sodium, 1% by weight of citric acid as an acid, and 28% by weight of water was obtained.

[Production Example 7: Production of hydrogel sheet containing a large amount of inorganic salt]
In Production Example 1, except that the amount of sodium chloride in the monomer mixture was changed to 2.5 parts by weight, the procedure was the same as in Production Example 1, and 2.5 wt.% As an inorganic salt with respect to the total weight of the conductive hydrogel sheet. A conductive hydrogel sheet having a film thickness of 0.3 mm containing 1% by weight sodium chloride, 1% by weight citric acid as an acid, and 28% by weight water was obtained.

[Production Example 8: Production of hydrogel sheet containing a large amount of inorganic salt]
In Production Example 1, except that the amount of sodium chloride in the monomer compounded liquid was changed to 2.5 parts by weight, and the thickness of the silicone rubber sheet mold was changed to 0.6 mm, the same procedure as in Production Example 1, A conductive film with a thickness of 0.6 mm containing 2.5% by weight of sodium chloride as an inorganic salt, 1% by weight of citric acid as an acid, and 28% by weight of water, based on the total weight of the conductive hydrogel sheet A hydrogel sheet was obtained.

[Production Example 9: Production of hydrogel sheet containing a small amount of inorganic salt]
In Production Example 1, except that the amount of sodium chloride in the monomer compounding solution was changed to 0.1 parts by weight and the thickness of the silicone rubber sheet mold was changed to 0.6 mm, the same procedure as in Production Example 1, A conductive film having a thickness of 0.6 mm containing 0.1% by weight of sodium chloride as an inorganic salt, 1% by weight of citric acid as an acid, and 28% by weight of water, based on the total weight of the conductive hydrogel sheet A hydrogel sheet was obtained.

[Production Example 10: Production of hydrogel sheet containing a small amount of inorganic salt]
In Production Example 1, the amount of sodium chloride in the monomer mixture was changed to 0.1 parts by weight, the amount of ion-exchanged water was changed to 38 parts by weight, and the thickness of the silicone rubber sheet mold was changed to 0.6 mm. Is the same procedure as in Production Example 1, containing 0.1 wt% sodium chloride as an inorganic salt, 1 wt% citric acid as an acid, and 38 wt% based on the total weight of the conductive hydrogel sheet. A conductive hydrogel sheet having a film thickness of 0.6 mm containing water was obtained.

[Production Example 11: Production of hydrogel sheet containing a small amount of inorganic salt]
In Production Example 1, 5 parts by weight of sodium chloride in the monomer mixture solution is 0.5 parts by weight of sodium sulfate, the amount of ion-exchanged water is 50 parts by weight, and the thickness of the silicone rubber sheet mold is 0.6 mm. Other than the change, in the same procedure as in Production Example 1, containing 0.5 wt% sodium sulfate as an inorganic salt, 1 wt% citric acid as an acid, based on the total weight of the conductive hydrogel sheet, and A conductive hydrogel sheet having a thickness of 0.6 mm containing 50% by weight of water was obtained.

[Production Example 12: Production of hydrogel sheet containing a small amount of inorganic salt]
In Production Example 1, except that the amount of sodium chloride in the monomer compounded solution was changed to 0.1 parts by weight and the thickness of the silicone rubber sheet mold was changed to 0.9 mm, the same procedure as in Production Example 1, A conductive film with a thickness of 0.9 mm containing 0.1% by weight sodium chloride as an inorganic salt, 1% by weight citric acid as an acid, and 28% by weight water based on the total weight of the conductive hydrogel sheet A hydrogel sheet was obtained.

[Production Example 13: Production of hydrogel sheet containing a small amount of inorganic salt]
In Production Example 1, the amount of sodium chloride in the monomer mixture was changed to 0.1 parts by weight, the amount of citric acid was changed to 0.2 parts by weight, and the thickness of the silicone rubber sheet mold was changed to 0.9 mm. Is the same procedure as in Production Example 1, containing 0.1% by weight sodium chloride as an inorganic salt, 0.2% by weight citric acid as an acid, and 28% by weight with respect to the total weight of the conductive hydrogel sheet. A conductive hydrogel sheet having a thickness of 0.9 mm containing the above water was obtained.

[Production Example 14: Production of hydrogel sheet containing no inorganic salt]
In Production Example 1, the same procedure as in Production Example 1 except that the amount of sodium chloride in the monomer compounding solution was changed to 0 parts by weight and the thickness of the silicone rubber sheet mold was changed to 0.9 mm. A conductive hydrogel sheet having a thickness of 0.9 mm containing 1% by weight citric acid as an acid and 28% by weight water but not containing sodium chloride as an inorganic salt with respect to the total weight of the conductive hydrogel sheet. Obtained.

[Production Example 15: Production of hydrogel sheet containing no inorganic salt]
In Production Example 1, the amount of sodium chloride in the monomer mixture was changed to 0 parts by weight, polyacrylic acid to 1 part by weight, and the thickness of the silicone rubber sheet mold was changed to 0.6 mm. A membrane containing 1% by weight citric acid as an acid and 28% by weight water but not containing sodium chloride as an inorganic salt in the same procedure as in Production Example 1 with respect to the total weight of the conductive hydrogel sheet A conductive hydrogel sheet having a thickness of 0.6 mm was obtained.

[Production Example 16: Production of hydrogel sheet containing no inorganic salt]
Manufacturing Example 1 except that the amount of sodium chloride in the monomer mixture was changed to 0 parts by weight, citric acid was changed to 0 parts by weight, and the thickness of the silicone rubber sheet mold was changed to 0.6 mm. A film having a thickness of 0.6 mm containing 28% by weight of water with respect to the total weight of the conductive hydrogel sheet but not containing sodium chloride as an inorganic salt and not containing citric acid as an acid in the same procedure as in Example 1. A conductive hydrogel sheet was obtained.

<II: Production of conductive laminated hydrogel sheet>
[Example 1]
Laminating the conductive hydrogel sheet with a film thickness of 0.3 mm containing a large amount of inorganic salt prepared in Production Example 1 and the conductive hydrogel sheet with a film thickness of 0.6 mm containing no inorganic salt prepared in Production Example 2, A conductive laminated hydrogel sheet having a total film thickness of 0.9 mm was obtained. In the obtained conductive laminated hydrogel sheet, the conductive hydrogel sheet layer containing a large amount of inorganic salt corresponds to the hydrogel sheet A layer, and the conductive hydrogel sheet layer not containing inorganic salt corresponds to the hydrogel sheet B layer. In the case of this example, the hydrogel sheet A layer is disposed on the upper surface of the hydrogel sheet B layer.

[Example 2]
In Example 1, except that the hydrogel sheet B layer was changed to a conductive hydrogel sheet having a thickness of 0.9 mm and containing no inorganic salt prepared in Production Example 3, the total film thickness was 1.2 in the same procedure as in Example 1. A conductive laminated hydrogel sheet of mm was obtained.

[Example 3]
Two conductive hydrogel sheets with a thickness of 0.3 mm containing a large amount of inorganic salt prepared in Production Example 1 and two conductive hydrogel sheets with a thickness of 0.6 mm without inorganic salt prepared in Production Example 2 By alternately laminating, a conductive laminated hydrogel sheet having a total film thickness of 1.8 mm was obtained. In the obtained conductive laminated hydrogel sheet, the conductive hydrogel sheet layer containing a large amount of two inorganic salts is also referred to as a hydrogel sheet A layer (hereinafter referred to as “hydrogel sheet A layer” and “hydrogel sheet A ′ layer”). ) Corresponds to a hydrogel sheet B layer (hereinafter also referred to as “hydrogel sheet B layer” and “hydrogel sheet B ′ layer”), respectively. In the case of this example, the hydrogel sheet A layer is disposed on the upper surface of the hydrogel sheet B layer, the hydrogel sheet B ′ layer is disposed on the upper surface of the hydrogel sheet A layer, and the hydrogel sheet A ′ layer is disposed on the upper surface of the hydrogel sheet B ′ layer. Is placed.

[Example 4]
A conductive hydrogel sheet having a film thickness of 0.3 mm containing a large amount of inorganic salt prepared in Production Example 1 and a conductive hydrogel sheet having a film thickness of 0.6 mm not containing inorganic salt prepared in Production Example 2 were laminated, and In the meantime, cellophane (FP-300, manufactured by Nimura Chemical Co., Ltd.) was disposed as a semipermeable membrane to obtain a conductive laminated hydrogel sheet having a total thickness of 0.9 mm.

[Example 5]
In Example 1, the hydrogel sheet A layer was a conductive hydrogel sheet having a thickness of 0.6 mm containing a large amount of inorganic salt prepared in Production Example 5, and the hydrogel sheet B layer was a small amount produced in Production Example 9. A conductive laminated hydrogel sheet having a total film thickness of 1.2 mm was obtained in the same procedure as in Example 1, except that the conductive hydrogel sheet was changed to a 0.6 mm-thick conductive hydrogel sheet containing an inorganic salt.

[Example 6]
In Example 3, the hydrogel sheet A layer and A ′ layer, a conductive hydrogel sheet having a thickness of 0.6 mm containing a large amount of inorganic salt prepared in Production Example 5, and the hydrogel sheet B layer and B ′ layer, A conductive laminated hydrogel sheet having a total thickness of 2.4 mm was obtained in the same manner as in Example 3, except that the conductive hydrogel sheet having a thickness of 0.6 mm containing a small amount of inorganic salt prepared in Production Example 9 was used. It was.

[Example 7]
In Example 1, the hydrogel sheet A layer was a conductive hydrogel sheet having a thickness of 0.6 mm containing a large amount of inorganic salt produced in Production Example 5, and the hydrogel sheet B layer was produced in a small amount produced in Production Example 10. A conductive laminated hydrogel sheet having a total film thickness of 1.2 mm was obtained in the same procedure as in Example 1, except that the conductive hydrogel sheet was changed to a 0.6 mm-thick conductive hydrogel sheet containing an inorganic salt.

[Example 8]
In Example 1, the hydrogel sheet A layer was a conductive hydrogel sheet having a thickness of 0.6 mm containing a large amount of inorganic salt produced in Production Example 5, and the hydrogel sheet B layer was produced in a small amount produced in Production Example 11. A conductive laminated hydrogel sheet having a total film thickness of 1.2 mm was obtained in the same procedure as in Example 1, except that the conductive hydrogel sheet was changed to a 0.6 mm-thick conductive hydrogel sheet containing an inorganic salt.

[Example 9]
In Example 1, the hydrogel sheet A layer was a conductive hydrogel sheet having a thickness of 0.6 mm containing a large amount of inorganic salt prepared in Production Example 5, and the hydrogel sheet B layer was a small amount produced in Production Example 12. A conductive laminated hydrogel sheet having a total film thickness of 1.5 mm was obtained in the same manner as in Example 1 except that the conductive hydrogel sheet was changed to a 0.9 mm-thick conductive hydrogel sheet containing an inorganic salt.

[Example 10]
In Example 1, the hydrogel sheet A layer is a conductive hydrogel sheet having a thickness of 0.6 mm containing a large amount of inorganic salt prepared in Production Example 5, and the hydrogel sheet B layer is a small amount produced in Production Example 13. A conductive laminated hydrogel sheet having a total film thickness of 1.5 mm was obtained in the same manner as in Example 1 except that the conductive hydrogel sheet was changed to a 0.9 mm-thick conductive hydrogel sheet containing an inorganic salt.

[Example 11]
A 0.9 mm thick conductive hydrogel sheet containing a large amount of inorganic salt prepared in Production Example 6 and a 0.9 mm thick conductive hydrogel sheet containing no inorganic salt prepared in Production Example 14 were laminated, and In the meantime, an anion exchange membrane (manufactured by Astom Co., Ltd., ASE) was arranged as an ion exchange membrane to obtain a conductive laminated hydrogel sheet having a total film thickness of 1.8 mm.

[Example 12]
In Example 1, except that the hydrogel sheet B layer was changed to a conductive hydrogel sheet having a film thickness of 0.3 mm and containing no inorganic salt prepared in Production Example 4, the total film thickness of 0.6 was obtained in the same procedure as in Example 1. A conductive laminated hydrogel sheet of mm was obtained.

[Example 13]
In Example 1, except that the hydrogel sheet B layer was changed to a conductive hydrogel sheet having a film thickness of 0.6 mm and containing no inorganic salt prepared in Production Example 15, the total film thickness was 0.9 in the same procedure as in Example 1. A conductive laminated hydrogel sheet of mm was obtained.

[Comparative Example 1]
In Example 1, except that the hydrogel sheet B layer was changed to a conductive hydrogel sheet having a thickness of 0.6 mm containing a large amount of inorganic salt prepared in Production Example 5, the total film was prepared in the same procedure as in Example 1. A conductive laminated hydrogel sheet having a thickness of 0.9 mm was obtained.

[Comparative Example 2]
In Example 1, except that the hydrogel sheet B layer was changed to a conductive hydrogel sheet having a film thickness of 0.9 mm containing a large amount of inorganic salt prepared in Production Example 6, the same procedure as in Example 1 was followed. A conductive laminated hydrogel sheet having a thickness of 1.2 mm was obtained.

[Comparative Example 3]
In Example 1, the hydrogel sheet A layer is a conductive hydrogel sheet having a film thickness of 0.6 mm containing a large amount of inorganic salt prepared in Production Example 5, and the hydrogel sheet B layer is a large amount of inorganic prepared in Production Example 6. A conductive laminated hydrogel sheet having a total film thickness of 1.5 mm was obtained in the same manner as in Example 1 except that the conductive hydrogel sheet was changed to a 0.9 mm-thick conductive hydrogel sheet containing salt.

[Comparative Example 4]
In Example 1, the hydrogel sheet A layer is a conductive hydrogel sheet having a thickness of 0.3 mm that does not contain the inorganic salt produced in Production Example 4, and the hydrogel sheet B layer does not contain the inorganic salt produced in Production Example 2. A conductive laminated hydrogel sheet having a total film thickness of 0.9 mm was obtained in the same procedure as in Example 1, except that the conductive hydrogel sheet was changed to a 0.6 mm film thickness.

[Comparative Example 5]
In Example 1, the hydrogel sheet A layer is a conductive hydrogel sheet having a thickness of 0.3 mm that does not contain the inorganic salt produced in Production Example 4, and the hydrogel sheet B layer does not contain the inorganic salt produced in Production Example 3. A conductive laminated hydrogel sheet having a total film thickness of 1.2 mm was obtained in the same procedure as in Example 1 except that the conductive hydrogel sheet was changed to a 0.9 mm thick conductive hydrogel sheet.

[Comparative Example 6]
In Example 1, the hydrogel sheet A layer is a conductive hydrogel sheet having a thickness of 0.6 mm that does not contain the inorganic salt produced in Production Example 2, and the hydrogel sheet B layer does not contain the inorganic salt produced in Production Example 3. A conductive laminated hydrogel sheet having a total film thickness of 1.5 mm was obtained in the same procedure as in Example 1 except that the conductive hydrogel sheet was changed to a 0.9 mm film thickness.

[Comparative Example 7]
In Example 1, except that the hydrogel sheet B layer was changed to a conductive hydrogel sheet having a film thickness of 0.6 mm and containing no inorganic salt prepared in Production Example 16, the total film thickness was 0.9 in the same procedure as in Example 1. A conductive laminated hydrogel sheet of mm was obtained.

[Comparative Example 8]
In Example 1, the hydrogel sheet A layer is a conductive hydrogel sheet having a thickness of 0.3 mm containing a large amount of inorganic salt prepared in Production Example 7, and the hydrogel sheet B layer is a large amount of inorganic prepared in Production Example 8. A conductive laminated hydrogel sheet having a total film thickness of 0.9 mm was obtained in the same procedure as in Example 1, except that each was changed to a conductive hydrogel sheet having a thickness of 0.6 mm containing salt.

[Comparative Example 9]
In Example 1, the hydrogel sheet A layer is a conductive hydrogel sheet having a thickness of 0.6 mm that does not contain the inorganic salt produced in Production Example 2, and the hydrogel sheet B layer is a large amount of the inorganic salt produced in Production Example 1. A conductive laminated hydrogel sheet having a total film thickness of 0.9 mm was obtained in the same procedure as in Example 1, except that the conductive hydrogel sheet was changed to 0.3 mm.

<III: Evaluation of conductive laminated hydrogel sheet>
[III-1: Change in resistance when DC is applied]
Two sets of test materials were prepared, each sandwiching the conductive laminated hydrogel sheet of Example or Comparative Example cut into 25 mm square between two SUS plates. Of the two sets, the hydrogel sheet A layer (Examples 1, 2, 4, 5, and 7 to 12 and Comparative Examples 1 to 9) or the hydrogel sheet A ′ layer (Examples 3 and 6) side of one test material SUS plate, positive electrode of stabilized DC power supply (PAR18-6A, manufactured by TEXIO), hydrogel sheet B layer of other test material (Examples 1, 2, 4, 5 and 7-12, and Comparative Examples 1 to 9) or the negative electrode was connected to the SUS plate on the hydrogel sheet B ′ layer (Examples 3 and 6) side. In the two sets of test materials, a resistance of 1 kΩ was connected between the SUS plate on one hydrogel sheet B layer side and the SUS plate on the other hydrogel sheet A layer side, which was not connected to the positive electrode or the negative electrode. In the circuit, the resistance simulates the surface of the adherend, for example, the skin of a living body. A direct current was applied to the circuit under conditions of an applied DC voltage of 3 V and an application time of 10 minutes. The resistance of the circuit was measured, and the case where the resistance did not change was judged as ◯, and the case where the resistance increased was judged as x.

[III-2: Change in pH when DC is applied]
In accordance with the procedure described in III-1, a direct current was applied to the circuit to which the test material of the conductive laminated hydrogel sheet of the example or comparative example was connected. After application, the conductive laminated hydrogel sheet was removed from the test material. A pH test paper was placed on the surface of the hydrogel sheet B layer of the conductive laminated hydrogel sheets of Examples and Comparative Examples. Both surfaces of the conductive laminated hydrogel sheet were sandwiched between PET films and held for 1 minute. Thereafter, the pH test paper was taken out and the pH value was confirmed. In the same procedure, when measuring the pH value of the hydrogel sheet B layer in the conductive laminated hydrogel sheet of the examples and comparative examples before direct current application, in the case of the conductive laminated hydrogel sheet of any of the examples and comparative examples, The pH was 5. Based on the pH before DC application, the case where the pH value after application was in the range of 3 to 8 was judged as ◯, and the case where it was 2 or less or 9 or more was judged as ×.

[III-3: Evaluation results]
Table 1 shows the dimensions and inorganic salt amounts of the hydrogel sheet layers in the conductive laminated hydrogel sheets of Examples and Comparative Examples, and the evaluation results when direct current is applied to the conductive laminated hydrogel sheets.

  As shown in Table 1, in the conductive laminated hydrogel sheets of Examples 1 to 13, after the direct current was applied under the above conditions, the resistance value did not change, and the pH value of the hydrogel sheet B layer did not change. Or it was in the range of 5-8. In contrast, in the conductive laminated hydrogel sheets of Comparative Examples 1 to 3 and 7 to 9, the resistance value did not change after applying a direct current under the above conditions, but the pH value of the hydrogel sheet B layer was 9 Rose. Further, in the conductive laminated hydrogel sheets of Comparative Examples 4 to 6, after the direct current was applied under the above conditions, the pH value of the hydrogel sheet B layer did not change, but the resistance value increased.

  Regarding the conductive laminated hydrogel sheet of Example 3, the pH change was evaluated by the same procedure as described above after 7 days from the production of the conductive laminated hydrogel sheet. As a result, pH 5 was maintained. From this result, in the conductive laminated hydrogel sheet according to one aspect of the present invention, the effect of the present invention is expressed over a longer period of time by disposing a film between the hydrogel sheet A layer and the hydrogel sheet B layer. It became clear that it could be done.

101 ... Conductive laminated hydrogel sheet
301 ... Electrode pad
11, 11a, 11b, 11c… Hydrogel sheet A layer
12, 12a, 12b, 12c… Hydrogel sheet B layer
13, 13a, 13b, 13c, 13ab, 13bc ... membrane
14 ... Support base material
21 ... Electrode
S ... Surface of adherend

Claims (11)

A hydrogel sheet A layer having a thickness of a mm and a hydrogel sheet B layer having a thickness of b mm are alternately laminated,
The hydrogel sheet A layer contains at least one inorganic salt having a total content X wt% based on the total weight of the hydrogel sheet A layer, and the hydrogel sheet B layer has a total content Y with respect to the total weight of the hydrogel sheet B layer. % By weight of at least one inorganic salt, provided that Y is less than X;
The hydrogel sheet B layer contains at least one acid,
A conductive laminated hydrogel sheet having at least two hydrogel sheet layers.   2. The conductive laminated hydrogel sheet according to claim 1, wherein the at least one acid includes an organic acid. X and Y are the following formula (1):
0 ≦ Y <X ≦ 15 (1)
The conductive laminated hydrogel sheet according to claim 1 or 2, wherein When the water content of the hydrogel sheet B layer relative to the total weight of the hydrogel sheet B layer is α wt%, Y and α are the following formula (2):
0 ≦ Y / α ≦ 0.03 (2)
The conductive laminated hydrogel sheet according to any one of claims 1 to 3, wherein a and b are the following formulas (3) and (4):
b / a ≧ 1 (3)
0.6 ≦ a + b ≦ 3.0 (4)
The electrically conductive laminated hydrogel sheet according to any one of claims 1 to 4, wherein   A membrane selected from the group consisting of a semipermeable membrane, an ion exchange membrane, a microfiltration membrane, an ultrafiltration membrane, and a nanofiltration membrane is further disposed between the hydrogel sheet A layer and the hydrogel sheet B layer. The conductive laminated hydrogel sheet according to any one of 1 to 5.   An electrode pad comprising: the conductive laminated hydrogel sheet according to any one of claims 1 to 6; and an electrode electrically connected to the hydrogel sheet A layer or the hydrogel sheet B layer of the conductive laminated hydrogel sheet.   The conductive laminated hydrogel sheet according to any one of claims 1 to 6, and an electrode electrically connected to the hydrogel sheet A layer or the hydrogel sheet B layer of the conductive laminated hydrogel sheet, and conductive A biological electrode pad in which a hydrogel sheet A layer or a hydrogel sheet B layer that is not connected to an electrode of a laminated hydrogel sheet is used as a contact portion to a living body.   9. The biomedical electrode pad according to claim 8, and a power supply unit electrically connected to the electrode of the electrode pad, wherein the hydrogel sheet A layer of the biomedical electrode pad is on the positive electrode side, and the hydrogel sheet B layer is the negative electrode Biological electrotherapy devices arranged on the sides.   9. The biological electrode pad according to claim 8, which is used for applying a direct current.   10. The electrotherapy device for living body according to claim 9, which is used for applying a direct current.

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