JPS6211432A - Medical adhesive electrode - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a medical adhesive electrode in which an adhesive layer having excellent conductivity and adhesiveness is provided on the surface of an electrode plate.

(Conventional technology) When using medical measuring devices such as electrocardiographs, electromyographs, and electroencephalograms, or electrical therapy devices such as low-frequency therapy devices, electrodes are pasted on the skin surface and placed at specified locations on the skin surface. An electrical connection is made between the location and these devices. Various improvements have been made in the materials and shapes of medical skin electrodes, as well as in the means for fixing the electrodes to the skin surface. An example is shown below.

(1) The most commonly used method is to attach a metal electrode plate to the skin surface through a conductive medium such as a conductive paste cream or aqueous gel containing an electrolyte, but it has the following drawbacks: (1)-1 It requires skill to uniformly apply the conductive medium to the skin surface or electrode plate surface, and the application process is also complicated. It is necessary to wipe the skin surface after use; (1) -2 If measurements are performed over a long period of time, the moisture contained in the conductive medium will evaporate and the conductivity will change, resulting in variations in the measured values obtained. There is.

(1) -3 When measurements are taken over a long period of time or when measurements are taken while the person being measured is exercising, the electrodes tend to lift up from the skin, resulting in incomplete signal transmission between the skin surface and the measuring device. . - (1)-4 The components of the conductive medium cause skin irritation and rash.

(2) A method that uses an electrode whose contact portion to the skin surface is made of a sponge material, and when in use, the sponge absorbs water and presses the electrode against the skin surface.

Compared to method 11 above, there is no need to apply a conductive medium to the skin surface, and there is no skin irritation or rash caused by the conductive medium. The disadvantages due to water evaporation are also the same as in method (1).

(3) Japanese Patent Application Laid-Open No. 54-21080 discloses a medical electrode having an electrical terminal for extracting electrical signals from a living body to the outside through a sponge containing a conductive liquid or gel-like substance. Disclosed. In this electrode, a sponge is pressed against the skin surface using a porous adhesive sheet.

Such medical electrodes.

It can be easily fixed to the skin surface using an adhesive sheet, and the electrodes will not be lifted off the skin surface due to body movements of the subject. However, this medical electrode also has the following drawbacks: (3)-1 The sponge itself, which contains a conductive liquid or gel-like substance, has no adhesive force and is pressed onto the skin surface only by the pressure of the adhesive sheet. Therefore, the electrical contact may be incomplete or may become incomplete over time, resulting in variations in measured values.

(3) -2 Moisture in the conductive liquid contained in the sponge evaporates and the conductivity changes, which tends to cause variations in measured values. The product (electrode) must be sealed and packaged to prevent moisture evaporation, which increases costs.

(3) When the −3 electrode is peeled off from the skin, some of the conductive liquid or gel adheres to and remains on the skin surface, so it is necessary to wipe it off.

(3) -4 If the area of the sponge portion is set to a size sufficient for measurement, the area of the entire electrode including the adhesive sheet becomes large, which limits the range of use of the electrode. It also increases costs.

(4) JP-A-51-124082 discloses that adhesives (rubber-based adhesives; resin-based adhesives such as acrylate-based adhesives) commonly used for patches are blended with inorganic conductive particles such as metal. A medical electrode is disclosed in which a layer of conductive adhesive is provided on the surface of a metal electrode. Such an electrode can be easily fixed to the skin surface, similar to the method (3) in which a sponge containing a conductive liquid is pressed into contact with an adhesive sheet.

Since the adhesive itself has conductivity, the entire electrode can be made smaller. Since the adhesive does not contain water, there is no change in conductivity due to evaporation of water.

Moreover, no special packaging is required to prevent moisture evaporation.

However, such adhesives and electrodes using them have the following drawbacks: (The conductivity of the 41-1 adhesive depends on the amount of conductive particles mixed, 9 particle size, 1 dispersion state, etc.) influenced.

It is difficult to obtain adhesives with stable conductivity necessary for measurement. Further, unless a large amount of conductive particles are incorporated into the adhesive, a desired conductivity cannot be obtained. Therefore, if a large amount of conductive particles are incorporated into an adhesive, the adhesive strength will be significantly reduced.

+4) -2 When this electrode is used, electrical noise is likely to be mixed in due to the gap between the conductive particles in the adhesive and the adhesive.

(5) Adhesive electrodes have also been proposed in which a layer of an adhesive that does not contain conductive particles and is itself conductive is provided on the surface of an electrode plate. Such an electrode also has the same advantages as (4), and there is no need to mix conductive particles into the adhesive during preparation. As adhesives that can be used, conductive adhesives such as secondary adhesives have been proposed.

(5)-■ The electrode adhesive disclosed in JP-A-52-95895 is a combination of α, β-olefinically unsaturated carboxylic acid and a monohydric or polyhydric alcohol having a quaternary ammonium group at the end. Contains a polymer containing an ester and a polyhydric alcohol.

(5)-〇 The adhesive for the electrode disclosed in JP-A-56-36939 is a salt (alkali metal salt) of an organic carboxylic acid such as (meth)acrylic acid or maleic acid.

amine salt, etc.) in a proportion of 5 mol% or more, and a polyhydric alcohol such as glycerin.

(5)-〇 The electrode adhesive disclosed in JP-A-56-36940 contains a nonionic hydrophilic polymer such as polyvinyl alcohol and a water-soluble plasticizer such as glycerin.

However, the electrical conductivity of the three adhesives described above cannot be said to be sufficient. In particular, the adhesive (5)-(1) itself has extremely low conductivity and requires the addition of an electrolyte such as sodium chloride. All of them are insufficient in terms of adhesion and cannot keep the electrodes attached to the skin surface for a long period of time. In particular, the adhesive force of (5)-■ is low. (5) When an electrolyte is added to the adhesive of 〇-〇, the adhesive force decreases. Although the adhesive strength can be improved to some extent by changing the composition of these adhesives, it is still insufficient. Furthermore, in general, when the adhesiveness of the adhesive is set high, the conductivity tends to decrease.

(Problem to be solved by the invention) The present invention solves the above-mentioned conventional drawbacks.

The purpose is to provide a medical electrode that can be used in various medical measuring instruments and can be attached to a predetermined location on the skin with a simple operation.

Another object of the present invention is to have excellent conductivity and adhesiveness;
The object of the present invention is to provide a medical adhesive electrode in which a layer of adhesive having the following characteristics is provided on the surface of an electrode plate: (1) An adhesive that does not cause a change in conductivity due to evaporation of water contained in the adhesive. (2) An adhesive that has excellent internal cohesive force and does not cause adhesive cracking or adhesive residue; and (3) An adhesive that does not cause skin irritation.

Still another object of the present invention is to provide a medical skin electrode in which the conductive adhesive described above is provided on the surface of an electrode plate and has the following characteristics.

(1) A skin electrode that does not peel off from the skin surface even when used for a long time and can maintain a predetermined conductivity; and (2) A skin electrode that is less likely to be contaminated with electrical noise.

(Means for solving the problems) The medical adhesive electrode of the present invention is a medical adhesive electrode in which a conductive adhesive layer is provided on at least a part of an electrode plate,
The adhesive has a copolymer containing a first copolymer component and a second copolymer component as a main component.

(1) The first copolymerization component is a (meth)acrylamide derivative having a chemical structure in which a group having an allj-substituted ammonio group is bonded to a (meth)acrylamide group through an amide bond, and/or a group having a substituted ammonio group. is a (meth)acrylic acid ester derivative having a chemical structure bonded to a (meth)acrylic acid group through an ester bond; and (b) the second copolymerization component is a (meth)acrylic acid hydroxyalkyl ester; The above objective is achieved.

The copolymer which is the main component of the adhesive used in the electrode of the present invention is a (meth)acrylamide derivative (1) having the following structural formula and/or a (meth)acrylic acid ester derivative (It) as the first copolymer component. Contains as: (where RI is H or CHs; Rz is 1 carbon number
~6 saturated hydrocarbon groups iR+, R4 and R5 are alkyl groups having 1 to 4 carbon atoms; and X is a halogen atom such as CI, 'Br) (where r R6 is H or C
L; R? is a saturated hydrocarbon group having 1 to 6 carbon atoms or a saturated hydrocarbon group having 1 to 6 carbon atoms having a hydroxyl group;
R11, R9 and R1° are alkyl groups having 1 to 4 carbon atoms; and X is a halogen atom such as CI or Br)
.

Among the compounds represented by the above structural formula, (meth)acrylamide derivatives (I) include 3 (acrylamido)propyltrimethylammonium chloride, 3 (
Methacrylamide) propyltrimethylammonium chloride, 3 (acrylamide) isopentyltrimethylammonium chloride, 3 (acrylamide)
Propyltrimethylammonium iodide, 3 (
Examples include acrylamide)propyltrimethylammonium bromide and 3(methacrylamido)propyldimethylethylammonium chloride. As the (meth)acrylic acid ester derivative (n), 2 (methacryloxy)ethyltrimethylammonium chloride, 3
Examples include (methacryloxy)2hydroxypropyltrimethylammonium chloride, 2(acryloxy)ethyldiethylmethylammonium chloride, 3(acryloxy)propyltrimethylammonium chloride, and 3(acryloxy)propyltriethylammonium chloride.

The (meth)acrylic acid hydroxyalkyl ester which is the second copolymerization component includes 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, and methacrylate. 2-hydroxybutyl acid.

Examples include 3-hydroxybutyl acrylate and 3-hydroxybutyl methacrylate. Furthermore, it is preferable that a third copolymer component is contained in addition to the first and second copolymer components. The third copolymerization component is (meth)acrylic acid alkyl ester.

Alkyl vinyl ester, vinylpyrrolidone, diacetone acrylamide, (meth)acrylamide, N-alkyl (meth)acrylamide, N-alkoxyalkyl (meth)acrylamide, alkoxyalkyl (meth)acrylic acid ester.

At least one selected from the group consisting of (meth)acrylic acid, (anhydrous)maleic acid, polypropylene glycol (meth)acrylate, polyethylene glycol (meth)acrylate, and glycidyl (meth)acrylate is used.

The copolymer contains the first copolymer component in an amount of 20% by weight or more, and the second copolymer component in an amount of 10% by weight or more. When a third copolymer component is contained, the third copolymer component is
The copolymerization component is contained in a proportion of 50% by weight or more of the remaining components of the first and second copolymerization components. 1st. Second
Two or more kinds of the third copolymer components may be mixed.

What is the electrical conductivity of adhesives prepared using copolymers?

This is mainly due to the first copolymer component in the copolymer. Therefore, if the first copolymer component is too small, conductivity cannot be obtained substantially. The degree of conductivity also varies depending on the chemical structure of the first copolymer component. When the first copolymerization component is a (meth)acrylamide derivative, the resulting adhesive has higher conductivity than when it is a (meth)acrylic acid derivative. usually.

The conductivity of the adhesive obtained when a (meth)acrylic acid derivative is used is about 70% or less of that when a (meth)acrylamide derivative is used.

Even if the copolymer does not contain the second copolymer component and instead contains a copolymer component other than the second copolymer component, conductivity can be obtained as long as the first copolymer component is contained. It will be done. Even in such a case, when a (meth)acrylamide derivative is used as the first copolymerization component, the resulting adhesive has higher conductivity and adhesiveness. but,
In addition to the first copolymer component, the second copolymer component is added in the above proportion (1
The conductivity of the copolymer containing 0% by weight or more is about 2% compared to the polymer to which the second copolymer component is not added.
0% higher. Approximately 20% improvement in electrical conductivity is observed both when the first copolymer component is a (meth)acrylamide derivative and when it is a (meth)acrylic acid ester derivative. The degree of tackiness is also improved by containing the second copolymer component.

This is considered to be because the second copolymer component is copolymerized to strengthen the properties of the first copolymer component. In addition to the above-mentioned conductivity and adhesiveness, the following effects can be obtained by copolymerizing the first copolymer component and the second copolymer component.

(2) The internal cohesive force of the resulting adhesive increases.

(2) The degree of change in the physical properties of the adhesive due to ambient temperature is reduced, and an adhesive with stable adhesiveness and conductivity can be obtained.

(2) It becomes possible to contain a larger amount of the softener described below than in a polymer that does not have a second copolymer component. Therefore, by adjusting the amount of softener, an adhesive having desired conductivity and adhesive properties can be obtained. It is also easy to adjust the amount of softener.

The higher the content of the first and/or second copolymer components, the higher the degree of hydrophilicity (water solubility) of the copolymer. If the degree of hydrophilicity is too high, the copolymer exhibits hygroscopicity, resulting in disadvantages such as natural moisture absorption occurring during storage of the adhesive and changes in physical properties.

In such cases, it is possible to reduce the degree of hydrophilicity by copolymerizing the third copolymer component. When the third copolymerization component is added, it is easy to control the polymerization reaction during copolymerization, and gelation of the reaction solution due to runaway reaction does not occur, making it possible to obtain a polymer with a high polymerization rate.

When copolymerization is carried out by adding a small amount of a polyfunctional monomer (slightly crosslinking agent) in addition to the above-mentioned copolymerization components, the internal cohesive force of the resulting copolymer can be improved. An example of the polyfunctional monomer is Monomer 2, which has two or more (meth)acryloxy groups in its nine molecules.

1,6-hexane gelicoldi(meth)acrylate is preferably used. When a polyfunctional monomer is contained, crosslinking (slight crosslinking) occurs, albeit very slightly, during copolymerization, thereby increasing the internal cohesive force of the copolymer. Therefore, when a sheet or tape using an adhesive containing the obtained copolymer is applied, the adhesive may protrude into the surrounding area, or
No part of the adhesive remains on the skin surface when the sheet or tape is removed. The polyfunctional monomer is added at a rate of 0.001 to 0.1% by weight of the total copolymerization components (total monomers) during polymerization.

Other polymerizable monomers may be copolymerized as long as they do not impair the characteristics of the copolymer, such as its electrical conductivity. Such other polymerizable monomers are copolymerized so that their content is less than 50% by weight of the remaining components of the first copolymerization component and the second copolymerization component.

The above-mentioned first copolymerization component and second copolymerization component, and if necessary, a third copolymerization component (all monomers), a polyfunctional monomer, and other polymerizable monomers are subjected to normal radical polymerization. Method 1 For example, a copolymer is obtained by subjecting it to a polymerization reaction using a solution polymerization method. In the case of the solution polymerization method, a solvent capable of dissolving each monomer used and the copolymer to be produced is used as the solvent. Such solvents vary depending on the composition of the monomers used, but examples include water, a water-alcohol mixture (alcohol includes methanol, ethanol, isopropanol, etc.), and alcohol.

An alcohol-ethyl acetate mixture is used. When the obtained copolymer is soluble in an organic solvent, it is preferable to carry out the reaction using an alcohol solvent in combination with an azobis catalyst described below.

To obtain a copolymer 9 For example, each of the above monomers and a solvent are charged into a reactor equipped with a reflux condenser, and the inside of the reactor is purged with an inert gas such as nitrogen.

Start adding the catalyst while heating (approximately 60°C) and stirring. It is necessary that the catalyst be dissolved in the solvent system during the double polymerization. Therefore, when the solvent of the 9 reaction system is an organic solvent, an azobis-based catalyst is preferably used. When the solvent of the reaction system is an aqueous solvent, a peroxide-based catalyst, a redox-based catalyst, or the like is preferably used. The amount of catalyst is usually in the range of 0.1 to 0.5 mol% based on the number of moles of all monomers. The catalyst is divided into appropriate portions and added to the reaction solution. The reaction temperature is usually 50 to 80°C. In such a reaction system containing the first and second copolymerization components, the copolymerizability is high and the risk of runaway reaction or gelation is relatively low.

Add a solvent to the reaction system to lower the viscosity.

It is necessary to control the reaction temperature to prevent runaway reactions. In particular, reaction control by solvent dilution is important. In this way, the reaction is usually carried out for about 40 hours or more, and a viscous solution containing the copolymer is obtained.

The copolymers obtained in this way vary depending on the type and amount of the copolymerized components, and may be sticky by themselves.9 They are usually non-tacky and are relatively brittle and hard resin-like in the dry state. It is. In a dry state, conductivity is not developed. However, when a suitable softener is added to the copolymer, the copolymer becomes soft and sticky, and functions as an adhesive.

The internal cohesive force is also moderate, and it has viscoelastic properties and exhibits electrical conductivity.

Water or a water-soluble substance is used as the softener. For example, when water is added to a copolymer, since the copolymer is highly hydrophilic, the added water is adsorbed by the copolymer molecules.

As this water evaporates, it acts as a softening agent. However, water may gradually evaporate and the conductivity may change slightly, so a water-soluble liquid or a water-soluble substance with high water retention is used instead of water. In particular, it is recommended to use a water-soluble liquid with a high boiling point. Softeners include 2, such as glycerin,
Diglycerin, propylene glycol, trimethylene glycol, α-butylene glycol.

2,3-butylene glycol, β-butylene glycol, α-amylene gelicol, 2,3-amylene gelicol, 2,4-amylene gelicol.

1,4-amylene gelicol, 1,5-bentanediol, trimethylolethane, dipropylene glycol,
polyethylene glycol, polypropylene glycol,
Sorbitol, triethanolamine alkyl sulfate, jetanolamine, triethanolamine, aminoalkylpropanol, diisopropanolamine, polyethyleneimine, lactic acid/lactic acid ester, sodium lactate,
Cationic surfactants such as alkyltrimethylammonium chloride, fatty acid jetanolamide.

Nonionic surfactants such as sorbitan alkyl ethers, amphoteric surfactants such as dimethyl alkyl betaines, liquid (poly) amino acid derivatives, starch sugars.

These include urea and magnesium chloride. Two or more kinds of softeners may be used in combination. Among the above, diglycerin and glycerin are particularly preferably used.

The amount of softener depends on the composition of the copolymer components and the type of softener.

The amount varies depending on the thickness of the adhesive layer, the desired degree of tackiness, etc., but is usually in the range of 100 parts by weight or less (100 phr or less) per 100 parts by weight of the copolymer. If the amount is too small, not only adhesiveness will not be developed but also conductivity will not be obtained.

If a softener is added to the copolymer to soften it and function as an adhesive, the copolymer will have sufficient electrical conductivity. If the amount of softener is excessive, the adhesiveness of the resulting pressure-sensitive adhesive will increase, but it will become soft and fluid.

When a carboxyl group-containing monomer such as acrylic acid is copolymerized as the third copolymerization component, it is also possible to carry out post-crosslinking with a post-crosslinking agent such as a polyvalent metal salt. When a post-crosslinking agent is added, the polymer is crosslinked, thereby further increasing the internal cohesive strength of the resulting pressure-sensitive adhesive. Furthermore, the adhesive may contain fillers and film strength modifiers (for example, polyvinyl alcohol) within a range that does not affect properties such as conductivity.

Water-soluble polymers such as polyvinylpyrrolidone) may also be contained.

(Left below) The thus obtained adhesive, which is mainly composed of a copolymer and a plasticizer, has electrical conductivity and is also hydrophilic (water-soluble).
It also has water absorption and antibacterial properties.

An adhesive having both of these properties cannot be obtained even if a polymer obtained by homopolymerizing the first and second copolymer components, respectively, is used. The copolymer in the above-mentioned pressure-sensitive adhesive is a molecule in which the first and second copolymer components, and optionally the third copolymer component, etc. are arranged so as to take advantage of their respective properties, and which can exhibit appropriate viscoelasticity. It is thought that they are copolymerized so that the chain length is increased.

When a softener is added, the entire resin softens as mentioned above,
To further enhance these properties.

It is thought that the above-mentioned valuable properties can be obtained.

A medical adhesive electrode is prepared by providing a layer of such a conductive adhesive on at least a portion of a conductive base material (electrode plate). The materials of the electrode plate are tin, aluminum, nickel, chromium, gold, and platinum.

Iron, copper, and their alloys are used. An electrode plate is formed from these metals as a metal foil having a thickness of 30 to 200 μm or as a laminate with a reinforcing backing member.

The reinforcing backing member includes a film made of resin such as polyethylene terephthalate, polyethylene, polypropylene, polyvinyl chloride, nylon, polyurethane, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, cellulose derivative, etc. Alternatively, there are sheets; paper, m-cloth, and non-woven fabric using natural fibers, synthetic fibers, etc. The reinforcing backing member itself may be a laminate. When a laminate with a reinforcing backing member is used for the electrode plate, the appropriate thickness of the metal foil is 10 to 30III. It is also possible to add electrical conductivity to the reinforcing backing member by mixing carbon particles or the like in advance. In addition, for example, conductive woven fabrics with metal vapor-deposited on the surface of the fabric and conductive woven fabrics made of threads with metal vapor-deposited on the surface are also suitable because they can be deformed to follow the bending and stretching of the skin.

To provide the adhesive on the surface of the electrode plate 9 For example, add a softener and other additives and solvents as necessary to the reaction solution containing the copolymer, and apply the adhesive solution on the conductive substrate. Spread to
dry. After casting the adhesive solution onto release paper and drying it,
It may also be transferred onto the surface of a conductive base material. The thickness of the adhesive layer is 1
00-1000 μm.

Preferably it is 100 to 500μ. Sufficient adhesion can be obtained even with such a relatively thin layer.

Its area is 1-100 cd. The thickness and area of the adhesive layer are appropriately set depending on the use of the electrode. The conductive base material on which the adhesive layer was formed in this way.

For example, it is subjected to punching processing while still covered with release paper.

An adhesive electrode with a desired shape can be obtained. The adhesive layer may be formed on the conductive substrate after it is prepared into a desired shape.

As shown in FIGS. 1 to 3, the adhesive electrode of the present invention includes 9, for example, a disk-shaped metal foil electrode plate 11, and this electrode plate 11.
It has a conductive adhesive layer 13 provided on one side. A release paper 14 treated with silicone or the like is pasted on the surface of the conductive adhesive layer 13 (the side that contacts the skin surface of the person to be measured). This release paper 14 protects the conductive adhesive layer 13, and is peeled off when the electrode is attached to the skin. A portion of the electrode plate 11 has a protrusion 110 that protrudes outward.
is provided.

The protrusion 110 is not provided with an adhesive layer, and is electrically connected to a medical measuring device such as an electrocardiograph (not shown) via a conductive wire. The conductor wire is connected to the protrusion 110 via a clip or the like.

A shallow cut groove 113 may be provided in a part of the surface of the protrusion 110 on which the conductive adhesive layer is formed. When using this adhesive electrode 1, this cut groove 113
By folding back the protrusion 110 so that the cut groove expands and attaching a clip or the like for connecting the conductor to the protrusion 110, the adhesive layer on the electrode plate II can be removed without the clip or the like coming into contact with the skin. 13 can be brought into close contact with the skin. As the electrode plate 21, for example, as shown in FIGS. 4 and 5, a laminate of a metal foil 212 and a backing member 211 may be used. In this case, the cut groove 213 is formed in the backing member 211 of the protrusion 210. If the electrode is an electrocardiograph electrode.

The diameter of the electrode plate is preferably 20 to 40 m. Adhesive layer 1
3 or 23 has a thickness of 100 to 1000 μm.

If the thickness is relatively thick, a reinforcing material 230 may be used, as shown in FIG. 5, to keep the entire electrode in a predetermined shape. As the reinforcing material,9 usually a coarse mesh woven fabric such as gauze is used. The adhesive electrode 3 using this reinforcing material 230 can be obtained by, for example, impregnating the reinforcing material 230 with an adhesive solution and drying it, and then adhering this to the surface of the electrode plate 21.

(Function) The adhesive used in the medical adhesive electrode of the present invention has excellent conductivity. A 10Hz sine wave alternating current of 100 μA was applied to the adhesive electrode obtained by applying this adhesive layer to the surface of the electrode plate.
When energized below, the impedance of the electrode is less than 80 Ω per cnl, preferably less than 30 Ω per cnl.

If such an adhesive electrode with excellent conductivity is used in a measuring device such as an electrocardiogram, good measurement sensitivity can be obtained. Adhesives also have excellent adhesive properties. The adhesive electrode of the present invention using such an adhesive can be easily adhered to a predetermined skin surface.
It can be fixed and can be kept in close contact with the surface of the skin 1 for a long time without using any reinforcing means for fixing. Even when measurements are taken while the subject is exercising, the electrodes do not easily come off from the skin surface.

Unlike conventional electrodes using water-based gel, they do not lift off the skin surface during use and cause variations in measured values. Because the adhesive itself is conductive.

Unlike conventional electrodes in which a conductive gel is fixed with an adhesive sheet, the electrodes do not become large and have excellent performance even if they are small and have a simple shape. Therefore, the electrode can be provided at low cost. Since the softener in the adhesive does not easily evaporate, the conductivity will not change during use or storage of the electrode and will not affect the measured value. Furthermore, since it does not contain metal powder, almost no electrical noise is detected. Since the adhesive has a large internal cohesive force, so-called adhesive residue phenomenon hardly occurs.

The adhesive is non-irritating to the skin and has antibacterial properties itself. Therefore, even if the electrode is attached to the skin for a long time, it is unlikely to cause a rash due to the adhesive.

Even if the area where the patch is applied becomes damp, bacteria will not breed and rashes due to secondary sensitization will not occur. Even if the electrode is stored for a long period of time, mold will not form on the adhesive. The adhesive is also hydrophilic, so even if adhesive remains after the electrode is peeled off from the skin, it can be easily washed off with water or wiped clean. Is possible. Copolymer contained in adhesive.

By adjusting the composition of the softener and the like, an adhesive having a desired degree of conductivity and adhesiveness can be obtained. Therefore, electrodes having adhesiveness and conductivity depending on the purpose of use can be prepared. Such electrodes are widely used in various medical measuring instruments, therapeutic devices, and the like.

(Example) 1 The invention will now be explained with reference to examples.

Preparation of (A) copolymer: (meth)acrylamide derivative (first copolymerization component) 3 (methacrylamide)
80 parts by weight of propyltrimethylammonium chloride, 30 parts by weight of 2-hydroxyethyl acrylate as a second copolymerization component, 70 parts by weight of butyl acrylate as a third copolymerization component, 1.6-hexane as a polyfunctional monomer. 0.05 parts by weight of recall dimethacrylate and ethyl alcohol as a solvent were charged into a reaction vessel equipped with a reflux condenser to form a 70% solution. The reaction was carried out at 60° C. for 24 hours and at 70° C. for 18 hours while stirring under a N 2 stream. As a polymerization catalyst, azobisisobutyronitrile was used in an amount of 0.3% by weight based on the total amount of the above monomers. The catalyst is 3
The mixture was divided into 12 times at different times and added to the reaction system.

If the viscosity of one reaction solution increases significantly during the polymerization reaction, especially in the initial stage of polymerization, stirring may become difficult and gelation or runaway reaction may occur, so the reaction solution was diluted with ethyl alcohol. The resulting reaction solution was a viscous, transparent solution.
The concentration of the copolymer contained was 33%, and the viscosity was 24.5% at 21'C. It was QQOcps.

(B) Preparation of adhesive electrode: 50 parts by weight of diglycerin was added to 100 parts by weight of the polymer component of the copolymer solution obtained in section (A) to obtain an adhesive solution.

This was cast onto the electrode plate base material so that the thickness after drying was about 200 μm and dried. In this case, the adhesive layer should not be formed on a part of the electrode plate base material.

The adhesive solution was cast. The electrode plate base material is a 50 μm thick polyethylene terephthalate (PET) film mixed with 5% by weight of titanium white and a 15 μm thick film.
The adhesive solution was cast onto the surface of the tin foil using a laminate body which was dry-bonded (bonding layer thickness: 5 μm) with a tin foil of 5 μm. Two transparent release papers made of PET film having a thickness of 50 μm and treated with a silicone release agent on one side were stacked on the resulting adhesive layer so that the release agent-treated surfaces were in contact with the adhesive layer.

This is the planar shape shown in Figure 1 (diameter 30m; protrusion width 10m).
An electrode was obtained by punching using a punching blade having a length of 15 mm. When performing the punching process, the punching blade was set so that the portion of the electrode plate base material where the adhesive layer was not formed corresponded to the protrusion of the punching blade.

The adhesive electrode thus obtained can be easily adhered to the skin surface by removing the release paper and pressing it to the skin surface, and can be used as a terminal electrode for an electrocardiograph or a low-frequency treatment device. Due to its strong adhesive strength, it does not easily peel off from the skin surface even over long periods of time or during exercise loads. - (C) Conductivity evaluation of adhesive layer: A laminate of the same quality as the electrode plate base material is closely attached to the adhesive layer surface of the electrode obtained in section (B) so that the tin foil surface is in contact with the adhesive layer surface. I let it happen. A sinusoidal voltage of 10 mV at 10 Hz was applied between both tin foils sandwiching the adhesive layer. Electrical resistance (
impedance) was calculated. Impedance is 0.6
It was Ω.

Preparation of large carbon-coated main (A) copolymer: 60 parts by weight of 3(methacrylamido)propyltrimethylammonium chloride as a (meth)acrylamide derivative (first copolymerization component);
50 parts by weight of 2-hydroxypropyl acrylate as the second copolymerization component, and 4 parts by weight of butyl acrylate as the third copolymerization component.
0 parts by weight and 30 parts by weight of vinyl acetate, 0.0 parts by weight of 1,3-butylene glycol diacrylate as a polyfunctional monomer.
A copolymer was prepared in the same manner as in Example 1 (A) using 05 parts by weight and ethyl alcohol as a solvent. The concentration of the copolymer contained in the obtained reaction solution was 29.4%
.

The viscosity at 21°C was approximately 21,000 cps.

(B) Preparation of adhesive electrode: 30 parts by weight of diglycerin and polypropylene glycol (
A pressure-sensitive adhesive solution was obtained by adding 20 parts by weight (molecular weight: about 800). Using this adhesive solution, an adhesive electrode was prepared according to the method in Section (B) of Example 1.

The obtained electrode has excellent adhesiveness similar to the electrode of Example 1 (B).

(C) Conductivity evaluation of adhesive layer: Evaluation was carried out according to Example 1 (C) using the electrode obtained in Section (B) of this example. The impedance was 0.8Ω.

Example 3 (A) Preparation of copolymer: 3 as (meth)acrylamide derivative (first copolymerization component) 80 parts by weight of (acrylamide)propyltrimethylammonium chloride 1
．． As the second copolymerization component, 10 parts by weight of 2-hydroxyethyl methacrylate and 30 parts by weight of 2-hydroxyethyl acrylate
parts by weight, 30 parts by weight of 2-ethylhexyl acrylate and 30 parts by weight of diacetone acrylamide as the third copolymerization component, 0.01 part by weight of 1,3-butylene glycol diacrylate as a polyfunctional monomer, and as a solvent. A copolymer was prepared using ethyl alcohol according to Section (A) of Example 1. The resulting reaction solution was a nearly transparent viscous liquid. The copolymer concentration was 33.8% and the viscosity at 21° C. was approximately 23.000 cps.

(B) Preparation of adhesive electrode: 40 parts by weight of Jigguse 9F and 10 parts by weight of diisopropanolamine per 100 parts by weight of the polymer component of the copolymer solution obtained in section (A) of this example.
Parts by weight were added and mixed uniformly to obtain an adhesive solution.

Separately, a nylon woven net with a thickness of about 200 μm and an opening area ratio of about 70% was prepared as a reinforcing material. After this reinforcing material was immersed in the adhesive solution, it was slowly pulled up, passed between two rolls with a diameter of 50 m, and then dried.

A double-sided adhesive sheet with a thickness of about 500 μm was obtained. Example 1
After sandwiching and adhering the electrode plate base material and release paper of the same quality as in section (B), punching was performed in the same manner as in section (B) of Example 1, resulting in the structure shown in Fig. 5. An adhesive electrode was obtained.

Since the adhesive electrode obtained in this way has a reinforcing material in the adhesive layer, the adhesive does not protrude from the electrode plate due to the flow of the adhesive when it is applied to the surface of the skin layer. This electrode can be used in two cases, for example, when the person to be measured sweats profusely; and (1) when using it in the summer when sweating is intense.

It is suitably used when measurements are taken over a long period of time or when measurements are taken while the person being measured is exercising.

(C) Evaluation of conductivity of adhesive layer (2) The electrode obtained in Example (B) was used in accordance with Example 1 (C). The impedance is 1. It was IKΩ.

Preparation of strawberry (A) copolymer = (meth)acrylic acid ester derivative (first copolymerization component): 2 (methacryloxy)ethyltrimethylammonium chloride 90
parts by weight, 50 parts by weight of dihydroxyl acrylate as the second copolymerization component, 60 parts by weight of butyl acrylate and 10 parts by weight of acrylic acid as the third copolymerization component, polyethylene glycol dimethacrylate (as the polyfunctional monomer) A copolymer was prepared according to Example 1 (A) using 0.01 part by weight (molecular weight: about 350) and ethyl alcohol as a solvent. The obtained reaction solution was a slightly milky white viscous solution, and the concentration of the copolymer contained was 36.3%.
, the viscosity at 21° C. was 26,000 cps.

(B) Preparation of adhesive electrode: For 100 parts by weight of the polymer component of the copolymer solution obtained in Section (A) of this example, 25 parts by weight of Jigurya 9F, polyethyleneimine (polymerization degree of about 20
0) 4 parts by weight, 15 parts by weight of 1,5-bentanediol, and 15 parts by weight of sodium lactate were added and mixed uniformly to obtain an adhesive solution. Example 1 using this adhesive solution
An adhesive electrode was prepared according to the method in section (B). However, the thickness of the adhesive layer is approximately 300 μm, and the adhesive solution is cast and
After drying, curing treatment was performed at 100° C. for 20 minutes.

The adhesive electrode thus obtained can be suitably used in electrocardiographs, low frequency therapy devices, etc., similarly to the electrode obtained in Section (C) of Example 1. Even if this electrode is used repeatedly, the adhesive strength of the adhesive does not easily decrease. When the adhesive strength has decreased, the adhesive strength can be restored by moistening the surface of the adhesive layer with water.

(C) Conductivity evaluation of adhesive layer: Evaluation was carried out according to Example 1 (C) using the electrode obtained in Section (B) of this example. The impedance was 1.2Ω.

1 (A) Preparation of copolymer: 100 parts by weight of (acryloxy)propyltrimethylammonium chloride (meth)acrylic acid ester derivative (first copolymerization component), 2 acrylic acid (second copolymerization component) 60 parts by weight of hydroxypropyl, 20 parts by weight of vinylpyrrolidone as the third copolymerization component, and 0.0 parts of polypropylene glycol diacrylate (molecular weight approximately 500) as the polyfunctional monomer.
A copolymer was prepared according to Example 1 (A) using 8 parts by weight and ethyl alcohol as a solvent. The resulting reaction solution was milky white, the concentration of the copolymer contained was 30.7%, and the viscosity at 21°C was approximately 27.000 cps.
Met.

(B) Preparation of adhesive electrode 2 20 parts by weight of Jigurya 9F, 30 parts by weight of lactic acid/lactic acid ester, and polyoxyethylene per 100 parts by weight of the polymer component of the copolymer solution obtained in Example (A). 10 parts by weight of sorbitan laurate (Nonion LT; trade name) was added and mixed uniformly to obtain an adhesive solution.

A dry bond laminate of high-quality bleached kraft paper with a basis weight of 90 g/m and tin foil with a thickness of 15 μm was used as the electrode plate base material. Using this electrode plate base material and the above adhesive solution, an electrode was prepared according to Section (B) of Example 1 to obtain an electrode having the structure shown in FIG. 4. However, the thickness of the adhesive layer was 350 μm.

(C) Conductivity evaluation of adhesive layer: Evaluation was carried out according to Example 1 (C) using the electrode obtained in Section (B) of this example. Impedance was 0.9Ω.

Preparation of Oarashi Tandate (A) copolymer: 70 parts by weight of 3(methacrylamido)propyltrimethylammonium chloride as the first copolymerization component and 30 parts by weight of 2(methacryloxy)ethyltrimethylammonium chloride as the second copolymerization component 50 parts by weight of dihydroxypropyl acrylate, 25 parts by weight of butyl acrylate and 5 parts by weight of glycidyl methacrylate as the third copolymerization component, 0 parts of trimethylolpropane triacrylate as a polyfunctional monomer
．． A copolymer was prepared according to Example 1 (A) using 0.006 parts by weight and ethyl alcohol as a solvent.

The resulting reaction solution was a slightly milky white viscous solution.

The concentration of the copolymer contained was 35.9%, and the viscosity at 21°C was 29.000 cps.

(B) Preparation of adhesive electrode: 20 parts by weight of diglycerin, 20 parts by weight of sorbitol, 50 parts by weight of water, and polyethyleneimine per 100 parts by weight of the polymer component of the copolymer solution obtained in section (A) of this example. (degree of polymerization approximately 200)
2 parts by weight were added and mixed uniformly to obtain an adhesive solution.

A laminate of nickel-plated woven fabric and polyurethane film was used as the electrode plate base material. The woven fabric used for this laminate has a thread count of 130 vertical threads/inch.
It is a woven fabric with 76 threads per inch and weighs approximately 50 g.
/rd. The weight of this nickel-plated fabric is approximately 63 g/rrr.

The polyurethane film was cast onto processing paper to a thickness of 30 μm and was used with the processing paper still attached. The elongation rate of the polyurethane film is 400% or more in both the vertical and horizontal directions. Separately prepare a polyethylene sheet and apply the above adhesive solution on its surface to a thickness of 400 mm after drying.
It was cast and dried to a thickness of μm. The nickel-plated surface of the electrode plate base material was brought into close contact with the surface of this adhesive layer. After this was subjected to punching according to the method of Example 1 (B).

The process paper was peeled off.

The adhesive electrode thus obtained has high conductivity. Since the electrode plate itself has elasticity, it can be deformed to follow the bending and stretching of the skin. Therefore.

For example, even when a measurement is performed while the person to be measured is exercising, it does not easily peel off.

(C) Conductivity evaluation of adhesive layer: Evaluation was carried out according to Example 1 (C) using the electrode obtained in Section (B) of this example. The impedance was 0.5Ω.

(Effects of the Invention) According to the present invention, a medical electrode can be obtained in which an adhesive having excellent conductivity and adhesiveness is provided on an electrode plate. This electrode can be easily applied to the skin surface and does not require any fixation aids. Because of its high electrical conductivity, the electrodes can provide highly accurate measurements when used in medical measurement equipment. Since the adhesive itself has conductivity, a small electrode can be formed with a simple structure, and therefore the electrode can be supplied at low cost. There is no change in conductivity during use or storage of the electrode, thus ensuring accurate measurements.

Almost no electrical noise is observed.

Since the adhesive has a large internal cohesive force, adhesive cracking and adhesive residue phenomena are less likely to occur. The adhesive does not irritate the skin, so
Even if the electrode is attached to the skin for a long time, it is unlikely to cause a rash. Since the adhesive itself has bactericidal properties, even if the area to which it is applied becomes damp, microorganisms will not propagate there and cause a rash due to secondary sensitization. Furthermore, since the adhesive has hydrophilic properties, even if the adhesive remains after the electrode is peeled off from the skin, it can be easily washed off with water or wiped clean. Since the tackiness and conductivity of the adhesive can be adjusted to a desired degree, an electrode can be obtained that meets the requirements. Such adhesive electrodes can be used in various medical measurement devices and treatment devices, and desired measurements can be easily and accurately performed.

[Brief explanation of drawings]

1 and 2 are a plan view and a bottom view showing an example of the medical adhesive electrode of the present invention, FIG. 3 is a side view thereof, and FIGS. 4 and 5 are respectively a plan view and a bottom view showing an example of the medical adhesive electrode of the present invention. FIG. 7 is a side view showing another example of an adhesive electrode. 1.2.3... Adhesive electrode, 11.21... Electrode plate, 13°23... Conductive adhesive layer, 110.210
···protrusion. that's all

Claims (1)

[Claims] 1. A medical adhesive electrode in which a conductive adhesive layer is provided on at least a portion of an electrode plate, the adhesive containing a first copolymer component and a second copolymer component. (1) the first copolymer component is (a) a (meth)acrylamide derivative having a chemical structure in which a group having a substituted ammonio group is bonded to a (meth)acrylamide group through an amide bond; and or (b) a (meth)acrylic acid ester derivative having a chemical structure in which a group having a substituted ammonio group is bonded to a (meth)acryloxy group through an ester bond; and (b) the second copolymer component is (meth) ) A medical adhesive electrode made of acrylic acid hydroxyalkyl ester. 2. The first copolymer component is 20% by weight in the copolymer.
The electrode according to claim 1, wherein the second copolymer component is contained in the above proportion and in a proportion of 10% by weight or more. 3. (meth)acrylic acid alkyl ester, alkyl vinyl ester, as a third copolymerization component in the copolymer,
Vinylpyrrolidone, diacetone acrylamide, (meth)acrylamide, N-alkyl(meth)acrylamide, N-alkoxyalkyl(meth)acrylamide,
Alkoxyalkyl (meth)acrylic ester, (meth)acrylic acid, (meth)maleic acid, polypropylene glycol (meth)acrylic ester, polyethylene glycol (meth)acrylic ester and (meth)
The electrode according to claim 1, containing at least one member selected from the group consisting of glycidyl acrylate. 4. In the copolymer, the third copolymer component is 50% by weight of the remaining components of the first copolymer component and the second copolymer component.
The electrode according to claim 3, which is contained in the above proportion. 5. The electrode according to claim 1, wherein the adhesive contains water or a water-soluble softener. 6. The electrode according to claim 5, wherein the adhesive contains the softener in a proportion of 100 parts by weight or less per 100 parts by weight of the copolymer.