JPS61137539A - Medical conductive pressure-sensitive agent and skin electrode using the same - 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 (Field of Industrial Application) The present invention relates to a medical adhesive having excellent conductivity and adhesiveness, and a medical skin electrode using the same.

(Prior art) When using medical measurement devices such as electrocardiographs, electromyographs, electroencephalograms, and electrical skin stimulation devices, electrodes are pasted on the skin surface and these devices are connected to predetermined locations on the skin surface. An electrical connection is made. 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 liquid, paste, cream, or aqueous gel containing an electrolyte, but it has the following drawbacks: -(11-1) Applying the above-mentioned conductive medium uniformly to the skin surface or electrode plate surface requires skill, and the application work is complicated. It is also necessary to wipe the skin surface after use; (1)-2 A fixing means such as adhesive tape is required to fix the electrode plate to the skin surface.

(1)-3 When measurements are carried out over a long period of time, the moisture contained in the conductive medium evaporates and the conductivity changes, resulting in variations in the measured values obtained.

<1)-4 In order to prevent the moisture contained in the conductive medium from evaporating during storage, it is necessary to store it in a sealed container.

(1) -5 If the fixing means loosens during measurement or the electrode is lifted from the skin due to the subject's body movement,
Signal transmission between the skin surface and the measuring device is incomplete.

(11-6 If the abrasive film of the conductive medium is thin or if there are thin parts due to uneven thickness of the abrasive film, the electrode plate will come into direct contact with the skin surface, causing burns.

(11-7 Depending on the components of the conductive medium, skin irritation or rash may occur.

(1)-8 Depending on the components of the electrolyte contained in the conductive medium, excess potential on the skin surface may occur.

(2) Compared to method (1) above, the method of impregnating and saturating a sponge with the conductive medium and applying the metal electrode plate to the skin surface through the sponge is different from method (1) above. It is easy to apply and has excellent adhesion to the skin surface, so it has excellent signal transmission, and since the electrode plate does not come into contact with the skin, there is no risk of burns, but in other respects it has the same drawbacks as method (1) above. has. Furthermore, if the pressure applied to the electrode plate by the fixing means is excessive, there is a risk that the electrically conductive medium may ooze out from the sponge.

(3) In method (2) above, the method of using an electrode that integrates a sponge impregnated and saturated with a conductive medium, a metal electrode plate, and adhesive tape as a fixing means is a method in which the electrode is pasted on the skin surface. It is advantageous in that it is simple and the electrodes can be disposable. However, changes in conductivity due to evaporation of water, stimulation of the skin layer by the conductive medium, excess potential on the skin surface due to electrolyte components, and oozing of the conductive medium from the sponge are the same as methods (1) and (2) above. It has its drawbacks. Furthermore, since such electrodes require special packaging to prevent moisture from evaporating during storage, the product cannot be provided at a low price.

(4) In the method of (3) above, in which a natural or synthetic hydrophilic polymer containing water or an aqueous electrolyte solution is used instead of the sponge impregnated with a conductive medium, the hydrophilic polymer is methylcellulose.

Compounds such as polyvinyl alcohol, polyvinylpyrrolidone, etc. can be utilized. When such an electrode is used, stable measurement values can be obtained without bleeding of the conductive medium. However, the disadvantages of changes in conductivity due to moisture evaporation and excess potential on the skin surface due to electrolyte components still remain.

Furthermore, when using natural hydrophilic polymers, there is a risk that microorganisms such as bacteria and mold will grow during storage. When microorganisms grow, the conductivity decreases and can cause skin irritation. If a preservative is added to prevent this, the preservative may cause damage to the skin layer. In addition, as with method (3) above, this method requires special packaging to prevent moisture evaporation, so the product cannot be provided at a low price.

(5) The method of using an electrode in which a conductive adhesive layer is provided on one side of a metal electrode plate is easy to handle because the adhesive itself has conductivity, and the structure is simple. Products can be provided at low prices. The conductive adhesive used can be used mainly in the following three ways ((5)
- Prepared by ■ to (5)-〇).

(5)-■ Conductive adhesives obtained by blending conductive particles such as metals and carbon with adhesives used in patches (glass transition point (T), 25°C to -55°C) are moisture-resistant. Since it does not contain any 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 the same have the following drawbacks.

(5)-■-1 The desired conductivity cannot be obtained unless a large amount of conductive particles are incorporated into the adhesive. For this reason, when a large amount of conductive particles are incorporated into an adhesive, the adhesive strength is significantly reduced.

(5)-■-2 When this electrode is used, electrical noise is likely to be mixed in in the voltage/current range at the level of a biological electrode.

(5)-〇 In the method of obtaining a conductive adhesive by blending a water-soluble plasticizer and an electrolyte with a natural or synthetic parent wood polymer, polyvinyl alcohol or methyl cellulose is used as the hydrophilic polymer as in the method (4) above. etc. are used. As the water-soluble plasticizer, for example, glycerin is used, and as the electrolyte, for example, sodium chloride is used. Electrodes using such conductive adhesives were disclosed in Japanese Patent Application Laid-Open No. 1986-
It is disclosed in Japanese Patent No. 36940. Such adhesives and electrodes have the following drawbacks.

(5)-〇-1 The conductivity of the adhesive depends on the electrolyte. Electrolytes such as sodium chloride do not inherently have very high conductivity, so they need to be blended in large amounts. As the proportion of electrolyte increases, the adhesive strength of the adhesive decreases.

(5)-■-2 A small amount of water is used to dissolve the electrolyte, but the evaporation of water changes the conductivity. Special packaging is required to prevent moisture evaporation, which makes it impossible to supply the product at a low price.

(5)-0-3 If a natural hydrophilic polymer is used, microorganisms such as bacteria and mold may grow. Add preservatives to prevent this.

This preservative may cause skin irritation.

(5)-■-4 The internal cohesive force of the adhesive is weak.

So-called adhesive cracking phenomenon and adhesive remaining phenomenon occur. It is necessary to embed a core material in the adhesive layer to reinforce the electrode.

(5)-〇 In the method of using a polymer containing a carboxyl group and/or an alkali metal salt of a carboxyl group as a conductive adhesive, the adhesive does not contain water as in the method of (5)-〇 above. Are better. An electrode using this is disclosed in Japanese Patent Laid-Open No. 56-36939. This adhesive and electrode also have the following drawbacks.

(5)-〇-1 The conductivity of polymers having carboxyl groups is not originally that high. If the carboxyl group is an alkali metal salt, the conductivity will be improved, but the adhesiveness will be reduced.

(5)-〇-2 Depending on the constitution of the person to be measured, applying an adhesive containing a carboxyl group may cause skin damage.

(5)-〇-3 The internal cohesive force of the adhesive is weak, resulting in adhesive cracking and adhesive residue phenomena. To prevent this, it is necessary to bury the core material.

(Problem that the invention attempts to solve) The present invention solves the above-mentioned conventional drawbacks.

The purpose is to provide a medical skin 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 provide a medical skin electrode in which an adhesive layer having excellent conductivity and adhesiveness is provided on the surface of the electrode plate. Yet another object of the present invention is that it can be used in the above-mentioned skin electrode. The object of the present invention is to provide an adhesive having excellent conductivity and adhesiveness, and having the following characteristics.

(1) Adhesives that are non-irritating to the skin and do not cause skin disorders due to the proliferation of microorganisms during storage; (2) Water is not an essential component of the adhesive, so water evaporates Adhesive that does not change conductivity: and (3) has excellent internal cohesive force, does not require embedding a core material in the adhesive layer of the electrode, and even if the adhesive layer is thin (usually 1
．． Otm or less) Adhesive that does not cause adhesive cracking or adhesive residue.

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.

(11) A skin electrode that does not peel off from the skin surface and maintains a certain level of conductivity even when used for a long time; (2) A skin electrode that is difficult to mix with electrical noise; and (3)
) Skin electrodes that do not generate excessive skin surface potential.

(Means for Solving the Problems) The medical conductive adhesive of the present invention is a (meth)acrylamide derivative having a substituent whose terminal is a quaternary ammonium salt via an amide group; and an alkyl group. The main component is a copolymer containing an acrylic acid alkyl ester having an average carbon number of 8 or less, thereby achieving the above object. Furthermore, there is a medical skin electrode of the present invention.

(Meth)acrylamide derivative 4 having a substituent whose end is a quaternary ammonium salt via an amide group; A polymer-based conductive adhesive layer is provided on one side of the electrode plate, thereby achieving the above object.

The copolymer which is the main component of the adhesive of the present invention contains a (meth)acrylamide derivative having the following structural formula as a constituent component.

Pir X- (where R1 is H or CH3, Rz has 1 to 6 carbon atoms
alkylene group, R3, Re and R3 are C1, or C, H, and X is C1 or Br. ) Among the compounds represented by the above structural formula, suitable examples include 3 (methacrylamido)propyltrimethylammonium chloride, 3 (acrylamido)propyltrimethylammonium chloride, 2 (acrylamido)ethyldiethylmethylammonium chloride, etc. .

The (meth)acrylamide derivative used in the present invention is contained in the components constituting the copolymer in a proportion of 15 to 70% by weight. The (meth)acrylamide derivative is a basic element for expressing the conductivity of the copolymer, and the higher the content, the higher the conductivity of the resulting adhesive, and conversely, if the content is too low, If the content of the below-mentioned acrylic acid alkyl ester is excessive, the resulting adhesive will have low conductivity.

If the (meth)acrylamide derivative is in excess, the copolymerizability with the acrylic acid alkyl ester described below will decrease, making it impossible to obtain a high molecular weight copolymer. Also.

Since a large amount of unreacted monomer remains, the cohesive force of the adhesive decreases, causing adhesive cracking and adhesive residue phenomena. Unreacted monomers can also cause skin irritation.

Furthermore, if the (meth)acrylamide derivative is present in excess, the water absorption of the obtained copolymer will be too high, resulting in changes in conductivity due to moisture absorption during storage of the adhesive or when used in electrodes.

The acrylic acid alkyl ester, which is another component of the copolymer, has an alkyl group having 8 or less carbon atoms. however,
Two or more types of acrylic acid alkyl esters may be used as a mixture, as long as the average number of carbon atoms in the alkyl group is 8 or less. The smaller the number of carbon atoms in the alkyl group, the greater the rigidity of the resulting copolymer. Therefore, a copolymer prepared using an acrylic acid alkyl ester having a short carbon chain requires the addition of a relatively large amount of the plasticizer described below. When the average carbon number of the alkyl group exceeds 8, copolymerizability with the (meth)acrylamide derivative deteriorates, and electrical conductivity decreases. Since the produced copolymer has low solubility in the solvent (alcoholic solvent), the two reaction solutions become microcolloidal, making handling inconvenient. In view of the above, butyl acrylate in which the alkyl group has 4 carbon atoms is particularly preferably used. The copolymer contains at least 50% by weight of the components other than the (meth)acrylamide derivative.
is prepared as an acrylic acid alkyl ester. If the proportion of the acrylic acid alkyl ester is small, the resulting copolymer will not exhibit sufficient tackiness. (
The blending ratio of the meth)acrylamide derivative and the acrylic acid alkyl ester depends on the polyfunctional monomer and other polymerizable monomers described below, the type and amount of the plasticizer used, and the desired adhesiveness of the adhesive. It is set appropriately in consideration of properties, conductivity, etc.

When copolymerization is carried out by adding a small amount of a polyfunctional monomer in addition to the above-mentioned (meth)acrylamide derivative and acrylic acid alkyl ester, the internal cohesive force of the resulting copolymer can be improved. A polyfunctional monomer refers to a monomer in which two or more (meth)acrylic acid ester groups are substituted at the ends of one molecule. For example, 1,6-hexane glycol dimethacrylate is preferably used. When a polyfunctional monomer is contained, crosslinking (
The internal cohesive force of the copolymer increases due to the occurrence of slight crosslinking. Therefore, even if a large amount of the plasticizer described below is added, the copolymer does not become fluidized, so a pressure-sensitive adhesive with high adhesive strength can be obtained. Furthermore, during storage of the adhesive or when using an electrode using the adhesive, it does not absorb moisture and soften or flow.

The polyfunctional monomer is added at a rate of 0.8% by weight or less based on the total polymerizable monomers during polymerization. If it is in excess, the resulting copolymer will have poor solubility in solvents such as alcohol and water.

Other polymerizable monomers may be copolymerized as long as they do not impair the characteristics of the copolymer of the present invention, such as electrical conductivity. Such polymerizable monomers include, for example,
Vinyl acetate, vinyl propionate, vinylpyrrolidone,
Dimethylacrylamide, diethylacrylamide, diacetone acrylamide, maleic anhydride, acrylonitrile.

(Meth)acrylic acid, methacrylic acid alkyl ester, polyethylene glycol mono(meth)acrylic ester, polypropylene glycol mono(meth)acrylic ester, and alkoxylalkyl (meth)acrylic ester. By appropriately selecting and containing these polymerizable monomers, it is possible to appropriately control the copolymerization reaction. By appropriately selecting the content, a copolymer having desired solubility can be obtained.

These other polymerizable monomers are copolymerized so that their content is at most 40% by weight or less of the total weight.

A copolymer is obtained by subjecting the above-mentioned (meth)acrylamide derivative and acrylic acid alkyl ester, and, if necessary, a polyfunctional monomer and other polymerizable monomers to a polymerization reaction by a conventional polymerization method. Among them, solution polymerization method is preferably used.

Alcohol-based solvents are preferably used as the solvent.
A copolymer is produced by a radical reaction.

When obtaining a copolymer by a solution polymerization method, the above monomers, catalyst and solvent are charged into a reactor equipped with a reflux condenser,
The reaction is carried out with stirring under an inert gas atmosphere. reaction,
The temperature varies depending on the type of monomer, but is usually 50-80℃.
Preferably it is 60 to 70°C.

As the catalyst, a commonly used azobis-based catalyst or the like is suitably used. The amount of catalyst is usually 0 based on the number of moles of total monomers.
．． A range of 2 to 0.5 mol% is adopted.

9 The catalyst is added to the reaction system in appropriate portions depending on the progress of the polymerization reaction. If the concentration of the reaction solution increases during the polymerization reaction and the stirring condition deteriorates, or if the reaction progresses rapidly and the reaction solution turns into a gel or there is a high possibility of a runaway reaction, add a solvent as appropriate to improve the reaction solution. Diluted. The concentration of monomers and the like in the reaction solution at the start of polymerization is preferably 60 to 90% by weight. Polymerization reaction usually starts from the beginning of polymerization.
0 to 40 hours is suitable.

If the copolymer solution obtained in this way is applied as is, the coating film will be a tough film, but the electrical conductivity of the film will not be fully exhibited yet. However, when a suitable plasticizer is added, the copolymer becomes soft and tacky, and also becomes significantly more conductive. The internal cohesive force is also moderate and it has viscoelastic properties. In addition to water, substances that act as plasticizers include water-soluble or hydrophilic liquids such as polyhydric alcohols and polyhydric alcohol derivatives.

However, as described in the prior art section, when water is used, the water evaporates from the adhesive, resulting in changes in conductivity, etc. Therefore, a plasticizer that does not contain water is suitable. Such plasticizers include high boiling water-soluble or hydrophilic liquids. For example, glycerin, diglycerin, low molecular weight polyvinyl methyl ether, alkylene glycol having 4 or more carbon atoms, polyethylene glycol.

Polypropylene glycol, allyl alkyl alcohol, liquid polysaccharide, liquid cationic surfactants such as alkyltrimethylammonium chloride having 12 or more carbon atoms, polyoxyethylene alkyl ether or ester, fatty acid jetanolamide, sorbitan alkyl ester, sorbitan polyoxy Examples include nonionic surfactants such as ethylene alkyl esters, amphoteric surfactants such as dimethyl betaine, liquid amino acids, and the like. Among these plasticizers, glycerin and diglycerin are particularly preferably used. Two or more plasticizers may be used in combination. The amount of plasticizer depends on the composition of the copolymer, the type of plasticizer,
Although it varies depending on the desired degree of tackiness, etc., it is usually in the range of 20 to 140% by weight, preferably 40 to 80% by weight of the copolymer. If a relatively hard adhesive is desired, the amount of plasticizer is reduced. If a soft adhesive is desired for attaching electrodes to hairy skin or skin with many deep wrinkles, the amount of plasticizer is increased. Care must be taken because adding too much plasticizer will increase the water absorption of the adhesive.

Plasticized copolymers also have significantly improved electrical conductivity. Although it varies depending on the composition of the copolymer, it is usually 1.

A sufficient amount of plasticizer is added to the copolymer to impart appropriate tackiness while at the same time providing appropriate conductivity.

In addition to the above-mentioned copolymer and plasticizer, the adhesive may contain a polymeric additive and the like within a range that does not impair the properties of the copolymer. As the polymer additive, a polymer soluble in alcoholic solvents is used. For example, polyvinylpyrrolidone, vinyl acetate-vinylpyrrolidone copolymer.

Diacetone acrylamide-vinylpyrrolidone copolymer, partially kephized polyvinyl acetate-maleic anhydride copolymer, vinyl acetate-maleic anhydride copolymer, methyl vinyl ether-maleic anhydride copolymer, 2-hydroxyethyl (meth) ) Copolymers of acrylic esters and (meth)acrylic esters, copolymers of 2-hydroxypropyl (meth)acrylic esters and (meth)acrylic esters, polyethyleneimine, methyl cellulose,
Examples include XfJLi cellulose, partially acetylated cellulose, and polyvinyl acetal. Two or more of these may be used in combination.

The above polymer additive is added for the purpose of adjusting the internal cohesive force of the adhesive. Basically, the desired internal cohesive force can be obtained by appropriately selecting the copolymer composition of the adhesive, but when it is desired to slightly change the magnitude of the internal cohesive force of an already prepared copolymer, this Polymer additives such as The polymeric additive can also be used as a mere filler, and by adding the polymeric additive, the adhesive can be provided at a low cost. The polymeric additive may be contained in the adhesive in an amount up to 20% by weight of the copolymer. If it is in excess, the adhesiveness and conductivity of the copolymer will be impaired.

The adhesive may further contain a filler in an amount of 20% by weight or less of the copolymer. Inorganic fillers are primarily used, including zinc oxide, calcium carbonate, magnesium carbonate, silicon oxide, and calcium silicate.

The adhesive prepared in this way has sufficient electrical conductivity, but if necessary, it is also possible to further add an electrolyte to improve the electrical conductivity. Electrolytes include 2, for example, organic acid alkali metal salts such as sodium succinate and sodium salicylate; inorganic salts such as sodium chloride and magnesium chloride.

Cationic surfactants such as octyltrimethylammonium chloride can also be added to serve as a plasticizer.

The conductivity of the adhesive prepared as described above is thought to be developed by the following mechanism. The quaternary ammonium salt at the end of the side chain of the (meth)acrylamide derivative incorporated into the copolymer is likely to dissociate into an ionic state. Since these quaternary ammonium salts in an ionic state are in close proximity to each other in the polymer, charge transfer occurs via the quaternary ammonium salt when a voltage is applied.

Since the movement of charges occurs in a chain, a current flows.

When a plasticizer such as glycerin is added to a copolymer, the molecular chain movement of the (meth)acrylamide derivative incorporated into the copolymer becomes active.

Therefore, it exhibits electrical conductivity and also has adhesive properties at the same time. The good flexibility of the molecular chain of the acrylic acid alkyl ester in the copolymer also activates the function of the (meth)acrylamide moiety that has the quaternary ammonium base, and as a result, the electrical conductivity of the entire copolymer increases. It is thought that it acts to increase the

A medical skin electrode is prepared by applying the resulting conductive adhesive layer to one side of a conductive substrate (electrode plate). for example,
As shown in FIGS. 1 to 3, nine skin electrodes 1 of the present invention are formed by providing the conductive adhesive layer 13 on one side of an electrode plate 11. 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 subject). This release paper 14 protects the conductive adhesive layer 13. When the skin electrode 1 is attached to the skin, it is peeled off. A protrusion 110 is provided at one end of the electrode plate 11, and as shown in FIG. 4, it is electrically connected to a medical measuring instrument 2 such as an electrocardiograph via a conductive wire 20 by means such as a clip. This projection 110 is covered with a suitable non-conductive sheet 15.

This prevents the electrode plate 11 from coming into direct contact with the skin.

As the electrode plate 11, a conductive base material such as a metal sheet such as aluminum foil, tin foil, or nickel foil, or cloth whose surface is coated with metal is suitably used. In order to provide the adhesive on the surface of the electrode plate 11, 1, for example, an organic solvent solution of the adhesive obtained by solution polymerization is cast onto a conductive substrate and dried. After casting the adhesive solution onto the release paper 14 and drying it, the electrode plate 1
It may be transferred onto one surface. The thickness of the adhesive layer 13 is 0.0
3m (30μm) or more, preferably 0.5-1.5f
It is l. When forming a relatively thick adhesive layer with a thickness exceeding 1.5 fl, a reinforcing material may be used to maintain the entire electrode in a predetermined shape. As a reinforcing material, 1 usually
A coarse mesh woven fabric such as gauze is used and embedded inside the adhesive layer 13.

(Function) The area of the adhesive layer on the electrode plate surface of such an electrode is 50 (ha2), and the applied voltage is 100 mV at 10 Hz.
In the following cases, the impedance of the electrode is 8 kΩ or less. When such electrodes with excellent conductivity are used, measurement sensitivity is improved. Since the adhesive has excellent adhesive properties, the electrode can be fixed to a predetermined skin surface without using reinforcing means for fixation, and accurate measurements can be made over a long period of time. This is because the adhesive does not need to contain water as a plasticizer or electrolyte solvent.

The conductivity will not change due to water evaporation during use or storage of the electrode, which will not affect the measured value. Furthermore, the adhesiveness does not decrease due to water evaporation. Furthermore, since it does not contain metal powder, almost no electrical noise is detected.

Since the internal cohesive force of the adhesive is also large, an adhesive layer of lj[ can be formed, and no reinforcing material is particularly required. When a polyfunctional monomer is added during copolymer preparation, a pressure-sensitive adhesive with even better internal cohesive strength can be obtained due to slight crosslinking. Electrodes using such adhesives do not suffer from so-called adhesive cracking or adhesive residue phenomena, regardless of the adhesive film thickness. Furthermore, since the adhesive is not a natural polymer, microorganisms will not propagate during storage and will not cause skin irritation. The copolymers used in adhesives are not post-crosslinked, so there is no skin irritation caused by unreacted monomers, and there is no need to include electrolytes in the adhesive, which can cause skin irritation. No excess potential occurs.

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

(A) Preparation of adhesive; (meth)-acrylamide ff
3 (methacrylamido)propyltrimethylammonium chloride t-66,5g (0,3
-11-l), 89.6 g (0.7 mol) of butyl acrylate as an acrylic acid alkyl ester, and 70 g of methyl alcohol as a solvent were charged into a reaction kolben + a polymerization reaction was carried out at 60°C with stirring under a NZ gas flow. went. As a polymerization catalyst, azobisisobutyronitrile 4
．． 1 g was used. The catalyst is 100mj! The mixture was dissolved in ethyl acetate, divided into 10 portions over 30 hours after the start of one reaction, and charged into a reaction vessel. When the viscosity of the reaction solution increased, methyl alcohol was added as appropriate. Further 65℃
The reaction was continued for 8 hours. The obtained reaction solution was transparent, and the concentration of the copolymer contained was 38.3%.
The viscosity was 21.000 cps at 20°C. The polymerization rate of each monomer in the copolymer is 3 (methacrylamide)
Propyltrimethylammonium chloride is 98.1
% and butyl acrylate was 98.8%. An adhesive solution was obtained by adding 17.0 g of diglycerin as a plasticizer to 100 g of this copolymer solution.

(B) Formation of adhesive layer and performance evaluation of adhesive strength = (A)
The adhesive solution obtained in Section 1 was cast onto a 50 μm thick polyethylene terephthalate (CPET) film base material so that the thickness after drying was 0.04 mm (40 μm) or more, and dried. The base material on which the adhesive layer is formed is 2.50
It was cut into a size of 1×2.5G+1 to obtain an adhesive sheet. This was pasted on the surface of the skin layer.

Avoid areas where the skin is directly bent, such as joints, when pasting.

Although the adhesive sheet was left in place for 6 hours, the adhesive sheet did not come off due to daily exercise. When this sheet was removed, the adhesive layer was temporarily stretched and peeled off from the skin surface. Appropriate adhesion was felt on the skin upon peeling.

No adhesive remained on the skin surface after peeling.

This adhesive sheet was cut into a tape shape with a size of 15 mm x 150 squares.
The adhesive force substitute characteristic value was measured by 180'' folding and peeling method).The value was 580 g per 15f1 width.

(C) Conductivity evaluation of adhesive layer: The adhesive solution obtained in section (A) was dried on silicone release paper so that the thickness after drying was 0.1.
m (100 μl 1 liter).

Dry. This adhesive was transferred onto aluminum foil. A 500 mm 2 piece of aluminum foil of the same quality was further placed on the surface of the transferred adhesive layer to obtain a sandwich-shaped test piece. A sinusoidal AC voltage of 10 H2, 10 mV was applied between the two aluminum foils of this test piece, and the effective current was measured. When the impedance was calculated from the value, the value was 1.2Ω.

Main stop plate (A) Preparation of adhesive = 82.7 g (0.4 mol) of 3 (acrylamido)propyltrimethylammonium chloride as a (meth)acrylamide derivative, and 55 g (0.4 mol) of 2-ethylhexyl acrylate as an acrylic acid alkyl ester. 2 g (0.3 mol).

0.13 g of 1,6-hexane glycol dimethacrylate as a polyfunctional monomer, and 42.6 g of butyl methacrylate as a polymerizable monomer other than the above.
(0.3 mol) to prepare a copolymer according to Example 1 (A). 100 g of ethyl alcohol was used as a solvent. The amount of polymerization catalyst was 4.9 g. The obtained reaction solution was a slightly milky white viscous solution, the concentration of the copolymer contained was 3955%, and the viscosity was 2700 at 20°C.
It was 0 cps. The polymerization rate of each monomer in the copolymer was 97.6% for 3 (acrylamido)propyltrimethylammonium chloride.

2-ethylhexyl acrylate was 99.0% and butyl methacrylate was 100%. This copolymer solution 10
An adhesive solution was obtained by adding 24 g of diglycerin as a plasticizer per 0 g.

(B) Performance evaluation of adhesive layer formation and adhesive strength (2) Example 1 (B) using the adhesive solution obtained in Example (A)
The adhesive layer was formed and the adhesive strength was evaluated in the same manner as in section ). The results were similar to those in Example 1 (B). However, the adhesive strength substitute characteristic value was 640 g per 15f width.

(C) Evaluation of conductivity of adhesive layer 2 Using the adhesive solution obtained in Example (A), the effective current was measured in the same manner as in Example 1 (C), and the impedance was calculated. The impedance of the test piece was 0.9Ω.

(A) Preparation of adhesive: 101.5 g (0.46 mol) of 2 (acrylamide) ethyl diethyl methyl ammonium chloride as a (meth)acrylamide derivative, 43 g (0.46 mol) of butyl acrylate as an acrylic acid alkyl ester. .5 g (0.34 mol), 0.13 g of 1,6-hexaneglycol dimethacrylate as a polyfunctional monomer, and 28.4 g of butyl methacrylate as a polymerizable monomer other than the above. (0,20
mol) to prepare a copolymer according to the method in Example 1 (A). Ethyl alcohol as a solvent
g was used. The amount of polymerization catalyst was 4.9 g. The obtained reaction solution was a transparent viscous solution, the concentration of the copolymer contained was 37.2%, and the viscosity was 24.000 cp at 20°C.
It was s. The polymerization rate of each monomer was 97.4% for 2 (acrylamido)ethyl diethyl methyl ammonium chloride, 99.1% for butyl acrylate, and 100% for butyl methacrylate. 20 g of benzyl alcohol and 12 g of diglycerin as a plasticizer, and 8 g of sodium succinate as an electrolyte were added to 100 g of the above copolymer solution to obtain an adhesive solution. Sodium succinate was dissolved in a small amount of water and added to the reaction solution at the same time as the plasticizer.

(B) Performance evaluation of adhesive layer formation and adhesive strength (2) Example 1 (B) using the adhesive solution obtained in Example (A)
The adhesive layer was formed and the adhesive strength was evaluated in the same manner as in section ). The results were similar to those in Example 1 (B). However, the adhesive force substitute characteristic value was 550 g per 15 m width.

(C) Conductivity evaluation of adhesive layer: Using the adhesive solution obtained in Example (A), effective current was measured in the same manner as in Example 1 (C), and impedance was calculated. The impedance of the test piece was 0.8 kΩ.

Preparation of main (A) adhesive: (meth)acrylamide derivative 3 (methacrylamide)propyl dimethyl
58.7g of ethyl ammonium chloride (0,2
5 mol) and 2 55.1 g (0.25 mol) of (acrylamido)ethyldiethylmethylammonium chloride, 51.2 g (0.4 mol) of butyl acrylate as an acrylic acid alkyl ester, and 51.2 g (0.4 mol) of butyl acrylate as a polyfunctional monomer. Propylene glycol dimethacrylate ester 0
．． Example 1
A copolymer was prepared according to the method in section (A). 70 g of ethyl alcohol was used as a solvent. The amount of polymerization catalyst was 4.9 g. The obtained reaction solution was a transparent viscous solution, the concentration of the copolymer contained therein was 36.6%, and the viscosity was 29,000 cps at 20°C. The polymerization rate of each monomer was 97.2% for 3(methacrylamido)propyldimethylethylammonium chloride and 98.9% for 2(acrylamido)ethyldiethylmethylammonium chloride.

Butyl acrylate is 98.6% and vinyl acetate is 9%.
It was 9.9%. Glycerin 18.0 as a plasticizer
g and low molecular weight polyvinyl methyl ether (Gant
-rez M 574) 12.0 g and 3.0 g of sodium chloride as an electrolyte to the above copolymer solution 10
It was added to 0g to obtain an adhesive solution. Sodium chloride was dissolved in a small amount of water and added.

CB)'t & Performance evaluation of adhesive layer formation and adhesive strength Example 1 using the adhesive solution obtained in Example (A)
Formation of an adhesive layer and evaluation of adhesive strength were performed in the same manner as in section (B). The results were similar to those in Example 1 (B). However, the adhesive strength substitute characteristic value was 720 g per 15 crane width.

((1) Conductivity evaluation of adhesive layer: Using the adhesive solution obtained in Example (A), effective current was measured in the same manner as in Example 1 (C), and impedance was calculated. The impedance of the test piece was 0.7Ω. (Effects of the Invention) According to the present invention, an adhesive having excellent conductivity and adhesiveness can be obtained. The skin electrodes obtained on the plate can be easily applied to the skin surface and do not require any auxiliary means for fixation, since the adhesive does not need to contain water as a plasticizer or electrolyte solvent. ,
During use or storage of the electrode, the conductivity changes due to water evaporation, thus providing accurate measurements. Adhesiveness does not decrease due to water evaporation. Also.

Since no special packaging is required to prevent water evaporation, the electrode can be provided at low cost. Almost no electrical noise is observed. Since the internal cohesive force of the adhesive is also large, a thick adhesive layer can be formed and no reinforcing material is particularly required. When a polyfunctional monomer is added during copolymer preparation, a pressure-sensitive adhesive with even better internal cohesive strength can be obtained due to slight crosslinking. Therefore, regardless of the thickness of the adhesive layer formed on the electrode, no adhesive cracking or adhesive residue phenomenon occurs. Since the adhesive is not a natural polymer, microorganisms will not grow during storage and will not cause skin irritation. Since the copolymer used in the adhesive is not post-crosslinked, skin irritation due to unreacted monomers does not occur. Since there is no need for the adhesive to contain electrolytes, excess skin potential caused by electrolytes does not occur. Such skin electrodes can be used in various medical measurement devices, and desired measurements can be made easily and accurately.

4. Figures 1 and 2 are a plan view and a bottom view showing an example of the medical skin electrode 1 of the present invention, Figure 3 is a side view thereof, and Figure 4 is a skin electrode. FIG. 1 is an explanatory diagram showing a usage state of the device.

1...Skin electrode, 2...Medical measuring device, 11...
- Electrode plate, 13... Conductive adhesive layer, 14... Peeling seam 15... Non-conductive sheet, 20... Conductive wire, 1
10... Protrusion.

that's all

Claims (1)

[Claims] 1. A (meth)acrylamide derivative having a substituent whose terminal is a quaternary ammonium salt via an amide group;
and a medical conductive adhesive comprising as a main component a copolymer containing an acrylic acid alkyl ester having an average carbon number of 8 or less in an alkyl group. 2. The copolymer contains the (meth)acrylamide derivative in a proportion of 15 to 70% by weight, and the remaining at least 50% by weight is the acrylic acid alkyl ester. adhesive. 3. The adhesive according to claim 1, which contains a plasticizer. 4. (meth)acrylamide derivative having a substituent whose terminal is a quaternary ammonium salt via an amide group;
and a medical skin electrode provided on one side of an electrode plate with a conductive adhesive layer mainly composed of a copolymer containing an acrylic acid alkyl ester having an average carbon number of 8 or less in an alkyl group. 5. The copolymer contains the (meth)acrylamide derivative in a proportion of 15 to 70% by weight, and the remaining at least 50% by weight is the acrylic acid alkyl ester. Skin electrode. 6. The skin electrode according to claim 4, wherein the conductive adhesive contains a plasticizer. 7. The skin electrode according to claim 4, wherein the conductive adhesive layer has a thickness of 0.03 mm or more. 8. The skin electrode according to claim 4, wherein at least the surface of the electrode plate is made of a conductive base material. 9. The area of the conductive adhesive in contact with the electrode plate is 500 m.
m^2 and the skin electrode according to claim 4, which has an impedance of 8 kΩ or less when the applied voltage is 100 mV or less at 10 Hz.