JPH0618560B2 - Medical conductive adhesive and medical adhesive electrode using the same - Google Patents

Description

The present invention relates to a medical conductive adhesive having excellent conductivity, adhesiveness and moisture resistance, and a medical adhesive having a layer of the adhesive on the surface of an electrode plate. Regarding the adhesive electrode.

(Prior Art) When using medical electrical equipment such as an electrocardiograph, an electromyography, an electroencephalograph, a low-frequency therapy device, and an electrosurgical knife, attach a signal electrode or a ground electrode to the skin surface. However, a predetermined place on the skin surface is electrically connected to these devices, or the skin surface is grounded. An adhesive electrode having a conductive adhesive layer provided on the surface of an electrode plate has been developed as a medical electrode used for such a purpose. As an adhesive that can be used for the adhesive electrode, for example, the following conductive adhesive has been proposed.

The adhesive for electrodes disclosed in Japanese Patent Publication No. 61-3506 is
It contains a polymer containing an ester of an α, β-olefinically unsaturated carboxylic acid and a monohydric or polyhydric alcohol having a quaternary ammonium group at the terminal, and a polyhydric alcohol.

The adhesive for electrodes disclosed in JP-A-56-36939 is
It contains a polymer containing a salt of an organic carboxylic acid such as (meth) acrylic acid or maleic acid (alkali metal salt, amine salt, etc.) in a proportion of 5 mol% or more and a polyhydric alcohol such as glycerin.

The adhesive for electrodes disclosed in JP-A-56-36940 is
It contains a nonionic hydrophilic polymer such as polyacrylic acid or polyvinyl alcohol and a water-soluble plasticizer such as glycerin.

However, it cannot be said that the adhesives of the above three examples have sufficient conductivity. In particular, the adhesive of (1) itself has extremely low conductivity, and it is necessary to mix an electrolyte such as sodium chloride. In terms of adhesiveness, none of them are sufficient, and the electrode cannot be adhered to the skin surface for a long time.

On the other hand, the inventor has already applied for an adhesive having sufficient conductivity and adhesiveness and suitable for the above-mentioned medical adhesive electrode (Japanese Patent Application No. 59-261549). This pressure-sensitive adhesive contains a (meth) acrylamide derivative having the following structural formula, a copolymer containing an alkyl acrylate having an alkyl group having an average carbon number of 8 or less as a copolymerization component, and a softening agent.

(Here, R ₁ is H or CH ₃ , R ₂ is an alkylene group having 1 to 6 carbon atoms, R ₃ , R ₄ and R ₅ are CH ₃ or C ₂ H ₅ , X is Cl or
Br. ) Due to the action of such a specific copolymer and the softening agent, the adhesive exhibits excellent conductivity and adhesiveness, but since it has a large hydrophilicity, it can be used under high humidity, especially in hot and humid conditions. It may swell or soften excessively due to the absorption of water, or may dissolve or flow out in the absorbed water. For example, such an inconvenience occurs during electrocardiographic monitoring of an infant in an incubator. The property of poor moisture resistance is
The same applies to the pressure-sensitive adhesive disclosed in this publication.

As described above, the adhesive agent for adhesive electrodes, which is excellent in conductivity, adhesiveness and moisture resistance, has not yet been obtained.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional drawbacks, and an object of the present invention is that it can be used in various medical measuring instruments and the like and has excellent conductivity and adhesiveness. And to provide a conductive adhesive having sufficient moisture resistance. Another object of the present invention is to provide a medical adhesive electrode in which an adhesive layer having the above-mentioned excellent properties is provided on the surface of an electrode plate.

(Means for Solving Problems) A conductive adhesive of the present invention has a substituted ammonio group and a carboxyl group and / or a carboxylic acid anhydride group, and is a polymer soluble in water and / or alcohol; 1 molecule Contains a glycidyl group-containing compound having two or more glycidyl groups and soluble in water and / or alcohol; and a softening agent, whereby the above object is achieved.

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 polymer having a substituted ammonio group and a carboxyl group and / or a carboxylic acid anhydride group and soluble in water and / or alcohol; having two or more glycidyl groups in one molecule, water and / or Alternatively, it contains a glycidyl group-containing compound soluble in alcohol; and a softening agent, whereby the above object is achieved.

The polymer, which is the main component of the medical conductive adhesive of the present invention, comprises a copolymerization component (first) of a (meth) acrylamide derivative (I) and / or a (meth) acrylic acid ester derivative (II) having the following structural formula. It is a copolymer contained as one copolymerization component).

(Wherein R ₁ is H or CH ₃ ; R ₂ is a saturated hydrocarbon group having 1 to 6 carbon atoms; R ₃ , R ₄ and R ₅ are alkyl groups having 1 to 4 carbon atoms; and X is Cl, Br. Is a halogen atom such as) (Here, R ₆ is H or CH ₃ ; R ₇ is a saturated hydrocarbon group having 1 to 6 carbon atoms or 1 to 6 carbon atoms having a hydroxyl group.
Saturated hydrocarbon group; R ₈ , R ₉ and R ₁₀ are alkyl groups having 1 to 4 carbon atoms; and X is a halogen atom such as Cl and Br).

Among the compounds represented by the above structural formulas, the (meth) acrylamide derivative (I) includes 2 (acrylamido) ethyltrimethylammonium chloride, 2 (methacrylamido) ethyltrimethylammonium chloride,
3 (acrylamide) propyltrimethylammonium chloride, 3 (methacrylamido) propyltrimethylammonium chloride, 3 (methacrylamido) propyldiethylmethylammonium chloride, 3 (methacrylamido) propyltrimethylammonium bromide, 3 (acrylamide) isopentyltrimethylammonium chloride, etc. There is. As the (meth) acrylic acid ester derivative (II), 2 (acryloxy)
Ethyltrimethylammonium iodide, 2 (methacryloxy) ethyltrimethylammonium chloride, 3 (acryloxy) propyltrimethylammonium chloride, 3 (methacryloxy) propyltrimethylammonium chloride, 3 (methacryloxy) 2-hydroxypropyltrimethylammonium chloride, etc. is there.

The polymer, which is the main component of the conductive adhesive of the present invention, further contains a monomer having a carboxyl group and / or a carboxylic acid anhydride group as a copolymerization component (second copolymerization component). The second copolymerization component is copolymerizable with the first copolymerization component and has a carboxyl group and / or a carboxylic acid anhydride group: A monomer having is used. These include, for example, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic anhydride and the like.

In addition to the first copolymerization component and the second copolymerization component, other monomers may be contained in the polymer as the third copolymerization component. As the third copolymerization component, a monomer is used that is copolymerizable with the first and second copolymerization components and the polymer formed is soluble in water and / or alcohol. As the third copolymerization component, ethyl (meth) acrylate, butyl (meth) acrylate,
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, ethoxyethyl (meth)
Acrylate, tetrahydrofurfuryl (meth) acrylate, glycerin mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, (meth)
There are acrylamide, N-dimethyl (meth) acrylamide, N-diethylacrylamide, N-butoxy (meth) acrylamide, vinyl acetate, vinyl propionate, vinylpyrrolidone, diacetone acrylamide and the like.

Two or more types may be mixed in each of the first, second and third copolymerization components.

In the copolymer, the first copolymerization component is 20 to 80% by weight, preferably 30 to 70% by weight, and the second copolymerization component is 5% by weight.
It is contained in a proportion of -80% by weight, preferably 10-50% by weight. If a third copolymerization component is included, it is 75
It is not more than 20% by weight, preferably 20 to 60% by weight.

The conductivity of the pressure-sensitive adhesive prepared using the copolymer is mainly due to the first copolymerization component in the copolymer. Therefore, if the first copolymerization component is too small, the conductivity cannot be substantially obtained. If the amount is excessive, the degree of polymerization will be low during the synthesis of the copolymer, and a low molecular weight polymer will be formed. When such a polymer is used as a pressure-sensitive adhesive, it lacks toughness and is apt to cause a cohesive failure phenomenon. The copolymer also has good hydrophilicity, which is also primarily due to the first copolymerization component.

The second copolymerization component is used for introducing a carboxyl group and / or a carboxylic acid anhydride group into the copolymer.
The carboxyl group or carboxylic acid anhydride group introduced into the copolymer has a function of forming a crosslinked body by a reaction with an epoxy group of a glycidyl group-containing compound described later. If the amount of the second copolymerization component is too small, the rate of formation of such a crosslinked product will be low, and the moisture resistance of the resulting pressure-sensitive adhesive will be poor. When the second copolymerization component is excessive and the first copolymerization component is excessively small, the resulting adhesive has poor conductivity. The third copolymerization component is added for the purpose of facilitating the polymerization and increasing the polymerization rate; adjusting the degree of polarity of the obtained copolymer; and imparting viscoelastic properties to the obtained copolymer. The type and amount of the third copolymerization component are appropriately determined according to the type and content of the first and second copolymerization components.

The copolymer can be prepared by an ordinary solution polymerization method (radical polymerization method) or the like. For example, first, the first and second
The copolymerization component, and optionally the third copolymerization component and the solvent are charged into a reactor equipped with a reflux condenser. Since most of the above-mentioned monomers have high hydrophilicity, alcohol or alcohol-water mixed solution is preferably used as the solvent. The charged concentration of the monomer is preferably 30 to 90%. Next, the inside of the reactor is replaced with an inert gas such as nitrogen, and the catalyst introduction is started while heating and stirring. As the catalyst, a catalyst usually used in a polymerization reaction, for example, azobisisobutyronitrile, t-butyl peroxide or persulfate is preferably used. The reaction temperature is usually 50-80 ° C. If the viscosity rises excessively during the polymerization reaction or the reaction temperature rises and there is a risk of runaway reaction or gelation, a solvent (eg ethyl alcohol) is added to the reaction system to decrease the viscosity. Is preferred to control the reaction. The reaction time varies depending on the monomer composition, the type and amount of the catalyst, the reaction conditions, etc., but is usually 20 to 50 hours. By such a method, a copolymer can be obtained with a high polymerization rate of 98% or more. Therefore, it is not necessary to separate and purify the copolymer from the solution by reprecipitation, and it can be used as it is in the production process of the adhesive.

The obtained copolymer may be tacky by itself depending on the kind and amount of the copolymerization component, but it is usually non-tacky, and is a relatively brittle and hard resin in the dry state. In the dry state, conductivity is not exhibited. This tendency becomes stronger as the proportion of the first copolymerization component increases. However, when an appropriate softening agent is added thereto, the copolymer softens and becomes tacky, and functions as an adhesive. The internal cohesive force also becomes excessive, and it has viscoelastic properties and exhibits conductivity.

As the softening agent, at least one of glycerin, diglycerin, water, and a mixture of magnesium chloride and water is used. Of these softeners, if water is used alone, it will be lost from the adhesive due to evaporation and the softening effect will be insufficient. Therefore, it is recommended to use it together with magnesium chloride as described above. Magnesium chloride acts as a moisturizer that retains moisture in the adhesive at a predetermined ratio. Magnesium chloride alone may be used. In this case, magnesium chloride absorbs water from the air, so that the adhesive contains water at a constant rate. Glycerin and diglycerin are non-volatile and can be used alone.

In addition to the above-mentioned softening agent, another compound may be used in combination as a softening aid to enhance the effect of the above-mentioned softening agent. Examples of such softening aids include propylene glycol, dipropylene glycol, trimethylene glycol, butylene glycols, amylene glycol, pentanediol, trimethylolethane, sorbitol, lower fatty acid diethanolamide, sorbitan allyl ether, and dimethylalkyl acetic acid betaine. , Starch, etc. Two or more kinds of softening agents and softening aids may be mixed and used.

The amount of the softening agent varies depending on the composition of the copolymerization component, the thickness of the pressure-sensitive adhesive layer, the desired degree of tackiness, etc., but when glycerin and / or diglycerin is used, it is usually added to 100 parts by weight of the copolymer. 20-110 parts by weight, preferably 40-
It is in the range of 80 parts by weight. Copolymer if water is used
The amount is 10 to 40 parts by weight, preferably 15 to 30 parts by weight, based on 100 parts by weight. When magnesium chloride is used, magnesium chloride hexahydrate (Mg
Cl ₂ · 6H ₂ O) is 10 to 60 parts by weight, preferably 20 to 40 parts by weight. If magnesium chloride is contained in such a proportion, for example, even if the copolymer is dry and does not contain any moisture, the action of magnesium chloride absorbs moisture in the air, and as a result, the pressure-sensitive adhesive will remain in a certain proportion. It comes to contain water. If the amount of the softening agent is too small, not only the tackiness is not exhibited but also the conductivity is not obtained. If the copolymer contains a softening agent and is softened and has an appropriate tackiness, the conductivity is sufficient. When the amount of the softening agent is excessive, the adhesiveness of the finally obtained pressure-sensitive adhesive increases, but it softens and has fluidity, causing cohesive failure of the pressure-sensitive adhesive layer.

The pressure-sensitive adhesive of the present invention further contains a glycidyl group-containing compound in addition to the above copolymer and softening agent. The glycidyl group-containing compound is a compound having two or more glycidyl groups in one molecule and soluble in water and / or alcohol. Examples of such a glycidyl group-containing compound include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and glycerol diglycidyl ether. , Glycerol triglycidyl ether, trimethylolethane diglycidyl ether, trimethylolethane triglycidyl ether, trimethylolpropane diglycidyl ether, trimethylolpropane triglycidyl ether, diglycerin diglycidyl ether, diglycerin triglycidyl ether, sorbitol polyglycidyl ether , Diglycidyl di Chiruhidantoin, triglycidyl isocyanurate, 3-methylpentane triol diglycidyl ether, and the like 3-methylpentane triol triglycidyl ether.

When the glycidyl group-containing compound is contained in the pressure-sensitive adhesive, the carboxyl group (or carboxylic acid anhydride group) derived from the second copolymerization component of the copolymer reacts with the epoxy group of the glycidyl group-containing compound to crosslink. Form the body. As a result, the pressure sensitive adhesive will not swell excessively due to moisture absorption or be dissolved by the absorbed water. That is, the pressure-sensitive adhesive becomes moisture resistant.

Such a glycidyl group-containing compound is blended so that the glycidyl group is stoichiometrically 0.3 to 3.0 times the ratio of the carboxyl group (carboxylic anhydride group converted to a carboxyl group) in the copolymer. To be done. If it is too small, the adhesive will have poor moisture resistance, and if it is too large, the adhesiveness will decrease.

The reaction between the carboxyl group (or carboxylic acid anhydride group) and the glycidyl group-containing compound is promoted by using the ammonio group of the copolymer itself as a catalyst, and a tertiary amine is further used as a reaction accelerator (crosslinking catalyst). You may add as. Such a reaction accelerator is added in a proportion of 0.1 to 5 parts by weight with respect to 100 parts by weight of the copolymer.

If the electrode plate of the adhesive electrode is made of a material that is susceptible to corrosion, such as tin or aluminum, it is recommended to add a metal corrosion inhibitor to the adhesive. As a corrosion inhibitor, when the softening agent is glycerin and / or diglycerin,
Alkali metal phosphate, ammonium phosphate, alkaline metal pyrophosphate, ammonium pyrophosphate, alkaline metal polyphosphate, ammonium polyphosphate, alkaline metal salicylate, ammonium salicylate,
Alkali metal citrate, ammonium citrate, double salts of the above salts, and the like are used. When the softening agent is magnesium chloride or water, hydroquinone and / or hydroquinone derivative is used as the corrosion inhibitor. Such a corrosion inhibitor is usually blended in a ratio of 5.0% by weight or less based on the whole adhesive. If it is excessive, the tackiness of the pressure-sensitive adhesive decreases. In addition, corrosion inhibitors can cause adhesives to cause skin irritation.

If necessary, the pressure-sensitive adhesive further contains additives such as a strength adjusting agent (cohesive strength adjusting agent) when the pressure-sensitive adhesive is formed into a film and a filler. A polymer soluble in water and / or alcohol may be used as the film strength modifier. For example, polyvinyl alcohol, pullulan, vinylpyrrolidone (co) polymer, (meth) acrylic acid (co)
Examples include polymers, hydroxyalkyl (meth) acrylate (co) polymers, cellulose derivatives, gum arabic, and karaya gum.

To prepare the pressure-sensitive adhesive of the present invention, for example, first, a solvent is added to the copolymerization solution prepared by the above-mentioned copolymerization reaction as needed to adjust the viscosity. A glycidyl group-containing compound, a softening agent, and if necessary, the above corrosion inhibitor,
A film strength adjusting agent or the like is added to obtain an adhesive solution. When the glycidyl group-containing compound, the softening agent, the corrosion inhibitor, etc. are themselves liquid, they are added as they are, and when they are powdery, they are added as an aqueous solution or alcohol solution having an appropriate concentration. Such various additives may be used as a mixture of two or more kinds.

The material of the electrode plate used for the medical adhesive electrode of the present invention includes tin, aluminum, nickel, lead, chromium, silver,
Gold, platinum, iron, copper and alloys of these are used. In particular, tin, aluminum and tin-aluminum alloy, which have excellent conductivity and are relatively inexpensive, are preferably used. An electrode plate is formed by forming these metals into a metal foil having a thickness of 50 to 10 μm or forming a laminate with a reinforcing backing member. The size of the electrode plate varies depending on its use, but in the case of an electrocardiograph electrode, its diameter is 30 to 40 mm. The reinforcing backing member is, for example, a film made of resin such as polyethylene terephthalate, polyethylene, polypropylene, polyvinyl chloride, nylon, polyurethane, ethylene-vinyl acetate copolymer, ethylene-acrylic ester copolymer, and fibrin derivative. Or a sheet;
There are paper, woven and non-woven fabrics made of natural fibers and synthetic fibers. The reinforcing backing member itself may be a laminate.

To prepare an adhesive electrode, for example, the above adhesive solution is continuously or spot-coated or cast on such a conductive substrate according to the size of a desired electrode. When glycerin or diglycerin is used as a softening agent,
The pressure-sensitive adhesive layer is formed by drying the above-mentioned coated and cast pressure-sensitive adhesive solution. When magnesium chloride-water is used as a softening agent, it is dried to an appropriate tackiness or completely dried to remove water and alcohol, and then left in an atmosphere of suitable humidity. It absorbs water and develops tackiness. A release paper is usually attached to the surface of the pressure-sensitive adhesive layer thus formed in order to protect the pressure-sensitive adhesive layer. To form the pressure-sensitive adhesive layer, the pressure-sensitive adhesive solution may be cast on a release paper, dried, and then transferred to the surface of the conductive substrate. The pressure-sensitive adhesive layer has a thickness of 100 to 400 μm. Even with such a relatively thin layer, sufficient tackiness can be obtained. The conductive base material on which the pressure-sensitive adhesive layer is formed in this manner is subjected to a punching process, for example, with release paper being applied thereto, and a pressure-sensitive adhesive electrode having a desired shape is obtained. The conductive base material may be prepared into a desired shape and then the adhesive layer may be formed thereon.

As shown in FIGS. 1 and 2, the adhesive electrode 1 of the present invention
Has, for example, a disk-shaped electrode plate 11 and a conductive adhesive layer 12 provided on one surface of the electrode plate 11. The electrode plate 11 is a laminate of a plastic sheet 111 and a metal foil 112. On the surface of the conductive pressure-sensitive adhesive layer 12 (the side that comes into contact with the skin surface of the person to be measured), a release paper 13 thinly coated with silicone or the like and cured is attached. The release paper 13 protects the conductive pressure-sensitive adhesive layer 12, and is peeled off when the electrode is attached to the skin. A protrusion 110 that protrudes outward is provided on a part of the electrode plate 11. No adhesive layer is provided on the protrusion 110, and as shown in FIG. 3, the protrusion 110 is electrically connected to the medical electric device 3 such as an electrocardiograph via a lead wire 31. . The conductor wire is connected to the protrusion 110 via a clip 32 or the like. A metal foil can also be used as the electrode plate. For such electrodes,
An electrode having the same structure as in FIGS. 1 and 2 can be used except that a metal foil is used instead of the laminated electrode plate 11.

(Operation) According to the present invention, as described above, an adhesive having excellent conductivity, adhesiveness and moisture resistance can be obtained. The conductivity and the degree of tackiness of the pressure-sensitive adhesive can be adjusted by the composition of the copolymer used and the amount of the softening agent, and a desired pressure-sensitive adhesive can be easily obtained. In this adhesive, the side chain carboxyl group (or carboxylic acid anhydride group) of the copolymer, which is the main component, reacts with the epoxy group of the glycidyl group-containing compound in the adhesive. By this reaction, the epoxy group is opened to bond the copolymer and the glycidyl group-containing compound. Since two or more glycidyl groups are present in the molecule of the glycidyl group-containing compound, the copolymer is crosslinked by the ring-opened glycidyl group-containing compound. Since the crosslinking reaction due to the ring opening of the epoxy group proceeds slowly, the solubility of the crosslinked copolymer in the solvent does not decrease in the solution, and the adhesive therefore gels, aggregates, or precipitates in a solvent such as alcohol. It can exist stably without causing Therefore, operations such as coating and casting of the adhesive solution can be easily performed, and the adhesive electrode can be manufactured with high accuracy. On the other hand, in the pressure-sensitive adhesive layer obtained by drying the pressure-sensitive adhesive solution, the usual physical properties of the crosslinking compound are exhibited. for that reason,
The amount of moisture absorbed from the outside air is low, and even when moisture is absorbed, it is suppressed from swelling or being dissolved by the absorbed moisture. That is, the adhesive has an affinity for water and is excellent in moisture resistance. The cross-linking does not reduce the conductivity or adhesiveness. The degree of crosslinking can be changed by appropriately adjusting the carboxyl group density of the copolymer and the amount of the glycidyl group-containing compound, so that a desired degree of moisture resistance can be obtained. Since the copolymer and the pressure-sensitive adhesive using the same are easily prepared, the conductive pressure-sensitive adhesive and the pressure-sensitive adhesive electrode using the same can be obtained at low cost. Since the adhesive electrode provided with the layer of the adhesive of the present invention on the surface of the electrode plate has excellent conductivity,
For example, good measurement sensitivity can be obtained when it is used for measuring equipment such as an electrocardiograph. Since the adhesive has moisture resistance, even when the adhesive electrode of the present invention is used, for example, when performing electrocardiographic monitoring of an infant in an incubator, the adhesive swells or dissolves due to high humidity, and the electrode becomes a skin surface. It does not come off. Since the cohesive strength of the adhesive is high due to crosslinking, so-called adhesive residue phenomenon due to cohesive failure does not occur.

Since the adhesive to which the corrosion inhibitor is added does not corrode the metal, even if the electrode is stored for a long time, the electrode plate will not be corroded and the conductivity will not change, and the conductivity of the adhesive itself will not change. There is nothing to do. Since the adhesive has no skin irritation, rash does not easily occur even if the electrode is applied to the skin surface for a long time.

(Examples) The present invention will be described with reference to Examples.

Example 1 (A) Preparation of adhesive: 3 (methacrylamido) propyltrimethylammonium chloride as first copolymerization component
40 parts by weight, 20 parts by weight of acrylic acid as the second copolymerization component,
40 parts by weight of butyl acrylate as the third copolymerization component and ethyl alcohol-water (weight ratio 70:30) as the solvent were charged into a reaction vessel equipped with a reflux cooling device to prepare a 40% solution. In an inert gas stream, stirring at 60 ° C for 24 hours,
Further, the reaction was carried out at 70 ° C for 24 hours. As the polymerization catalyst, azobisisobutyronitrile was added in an amount of 0.
Used at a rate of 7% by weight. The catalyst was charged into the reaction system every 5 hours in the first half of the reaction and every 3 hours in the second half. During the polymerization reaction, especially when the viscosity of the reaction solution rises sharply or the temperature rises sharply at the beginning of the polymerization, stirring may become difficult, and gelation or runaway reaction may occur, so the reaction solution was diluted with a solvent. . The reaction liquids after the completion of the polymerization reaction of the present Example and Examples 1 to 7 were transparent viscous liquids, each having a polymer concentration of 27 to 38% and an apparent viscosity of 20 ° C.
Was about 20,000-30,000 cps.

24 parts by weight of glycerin triglycidyl ether as a glycidyl group-containing compound, 50 parts by weight of diglycerin as a softening agent, and ethanol-water (70:30) were added per 100 parts by weight of the polymer component of the reaction solution containing the obtained copolymer. To obtain an adhesive solution of 15,000 to 25,000 cps. The glycidyl group-containing compound was added as an aqueous solution. The same applies to the following examples and comparative examples.

(B) Preparation of test piece: 40 μm thick lead alloy (lead: tin = 60: 4)
A laminated body of the sheet (0) and a PET sheet having a thickness of 50 μm was used as a substrate. The adhesive solution obtained in section (A) was cast on the metal surface of this substrate and dried to form an adhesive layer with a thickness of about 200 μm in the form of spots. A release paper was adhered to the surface of the adhesive layer, punched with a die, and cured at 80 ° C for 5 hours to obtain a test piece. This release paper is removed during the test.

(C) Evaluation of adhesive strength of adhesive: Using the test piece obtained in (B), the adhesive strength was evaluated by the probe tack test method according to ASTM-D-2979-71 (1982) (20 ° C, 65% RH). However,
The probe diameter is 8 mm, and the probe moving speed is 10 mm for both upper and lower
Seconds, probe contact time is 1 second, and probe contact load is 50 g. As a result, and Examples 2 to 7 described later,
The results of Comparative Examples 1 to 4 are also shown in Table 1.

(D) Conductivity evaluation of the adhesive: The new test piece obtained in the item (B) (including the part where the adhesive layer of at least 2 cm x 2 cm is formed and the part where the adhesive layer is not formed) Prepare
This was used as the lower electrode. Thickness on the adhesive layer of the lower electrode
A 15 μm tin foil 2 cm × 2 cm (upper electrode) was adhered. The portion of the lower electrode where the adhesive layer was not formed was used as the lower electrode terminal. Conductive wires were connected to the upper electrode and lower electrode terminals, respectively, and a sinusoidal voltage of 10 Hz and 10 mV was applied via the adhesive layer. The electric resistance value at that time was converted into a value per 1 cm ² , and this was used as impedance. The above measurement is 20
It was carried out at ℃ and 65% RH. The results are shown in Table 1. Example 2
Table 1 also shows the results of ~ 7 and Comparative Examples 1-4.

(E) Moisture resistance evaluation of adhesive: Fix one end of the test piece (about 2 cm x 6 cm) obtained in (B) and hang it so that the adhesive layer is vertical, 40 ℃, 85% It was left in an atmosphere of RH. 4,
The state of the pressure-sensitive adhesive layer was visually observed after 8, 12, 24, 36, 48 and 72 hours. The results are shown in Table 2. The results of Examples 2 to 7 and Comparative Examples 1 to 4 are also shown in Table 2. In Table 2, A to E were evaluated according to the following criteria.

A: It is in the same state as the pressure-sensitive adhesive layer immediately after preparation.

B: The adhesive layer slightly absorbs water and swells. When a finger touch test is conducted, the adhesive layer is very soft, and it is on the verge of stringing due to adhesion to the fingertip due to cohesive failure.

C: The pressure-sensitive adhesive layer absorbs water and swells, and when a finger touch test is performed, a part of the pressure-sensitive adhesive adheres to the finger surface, causing cohesive failure of the pressure-sensitive adhesive layer.

D: The pressure-sensitive adhesive layer is in a state of just before or partially flowing down due to water absorption.

E: The pressure-sensitive adhesive layer was dissolved by water absorption and completely flowed down.

Example 2 The same as Example 1 except that 5 parts by weight of a dimethylaminoethyl methacrylate polymer (molecular weight of about 10,000) was added as a crosslinking catalyst when the pressure-sensitive adhesive solution was prepared.

Example 3 40 parts by weight of 3 (methacrylamido) propyltrimethylammonium chloride as the first copolymerization component, 15 parts by weight of maleic anhydride as the second copolymerization component, and 25 parts by weight of vinyl acetate and N- as the third copolymerization component. Using 20 parts by weight of vinylpyrrolidone, a copolymer was prepared in the same manner as in Example 1 (A).

To 100 parts by weight of the polymer component of this copolymer solution, 31 parts by weight of trimethylolpropane triglycidyl ether as a glycidyl group-containing compound, 65 parts by weight of diglycerin as a softening agent, and a catalyst (the same compound as in Example 2) 5
An adhesive solution was prepared by adding parts by weight. Using this adhesive solution, a test piece was prepared according to Example 1 (B),
The performance of each pressure-sensitive adhesive was evaluated in the same manner as in Example 1 (C) to (E).

Example 4 50 parts by weight of 2 (methacryloxy) ethyltrimethylammonium chloride as the first copolymerization component, 20 parts by weight of acrylic acid and 20 parts by weight of methacrylic acid as the second copolymerization component, and acrylic acid 2 as the third copolymerization component. A copolymer was prepared according to Example 1 (A) using 10 parts by weight of -hydroxyethyl.

To 100 parts by weight of the polymer component of this copolymer solution, 26 parts by weight of sorbitol tetraglycidyl ether as a glycidyl group-containing compound, 70 parts by weight of diglycerin as a softening agent, and 5 parts by weight of a crosslinking catalyst (the same compound as in Example 2). Parts were added to prepare an adhesive solution. Using this pressure-sensitive adhesive solution, test pieces were prepared according to Example 1 (B).
Using the obtained test pieces, various evaluations of the pressure-sensitive adhesive were performed in the same manner as in Example 1 (C) to (E).

Example 5 20 parts by weight of 3 (acrylamide) isopentyltrimethylammonium chloride and 2 as the first copolymerization component
20 parts by weight of (methacryloxy) ethyltrimethylammonium chloride, 20 acrylic acid as the second copolymerization component
A copolymer was prepared according to Example 1 (A) using 1 part by weight, 10 parts by weight of maleic anhydride, and 30 parts by weight of ethoxyethyl acrylate as the third copolymerization component.

To 100 parts by weight of the polymer component of this copolymer solution, 60 parts by weight of triglycidyl isocyanurate as a glycidyl group-containing compound, 75 parts by weight of diglycerin as a softening agent, and 7 parts by weight of a crosslinking catalyst (the same compound as in Example 2). Was added to prepare an adhesive solution. Using this pressure-sensitive adhesive solution, test pieces were prepared in the same manner as in Example 1, and Examples 1 (C) to (E)
Each performance evaluation of the pressure-sensitive adhesive was carried out in the same manner as in the above item.

Example 6 Example 2 except that 70 parts by weight of sorbitol tetraglycidyl ether was used as the glycidyl group-containing compound, the amount of the softening agent was 55 parts by weight, and the amount of the crosslinking catalyst was 8 parts by weight.
Is the same as.

Example 7 The same as Example 3 except that 30 parts by weight of triglycidyl isocyanurate was used as the glycidyl group-containing compound and the amount of the softening agent was 70 parts by weight.

Comparative Example 1 The same as Example 1 except that the glycidyl group-containing compound was not added as an adhesive component and the amount of diglycerin was 45 parts by weight.

Comparative Example 2 The same as Example 3 except that the glycidyl group-containing compound and the crosslinking catalyst were not added as the adhesive component, and the amount of diglycerin was 60 parts by weight.

Comparative Example 3 The same as Example 4 except that the glycidyl group-containing compound and the crosslinking catalyst were not added as the pressure-sensitive adhesive component, and the amount of diglycerin was 65 parts by weight.

Comparative Example 4 The same as Example 5 except that the glycidyl group-containing compound and the crosslinking catalyst were not added as the adhesive component and the amount of diglycerin was 50 parts by weight.

From Table 1 and Table 2, it is clear that the pressure-sensitive adhesive of the present invention has excellent adhesiveness and conductivity, and has sufficient moisture resistance due to the action of the glycidyl group-containing compound.

(Effects of the Invention) According to the present invention, as described above, an adhesive having excellent conductivity and adhesiveness can be obtained. The adhesive electrode of the present invention in which such an adhesive layer is provided on the surface of the electrode plate is excellent in adhesiveness to the skin and has excellent conductivity, and thus is suitable for medical measuring instruments such as an electrocardiograph. When used, good measurement sensitivity can be obtained. Despite the relatively high hydrophilicity of the adhesive, it does not swell excessively by absorbing water or dissolve in the absorbed water. Therefore, for example, an adhesive electrode using this adhesive can be used under high temperature and high humidity conditions. It is also possible to use it for a long time. Since the adhesive does not irritate the skin, rash does not easily occur even if the electrode is applied to the skin surface for a long time. Such an adhesive electrode can be widely used in medical electrical devices such as an electrocardiograph, an electromyography, an electroencephalograph, and a low-frequency therapeutic device.

[Brief description of drawings]

1 and 2 are a plan view and a side view, respectively, showing an example of the medical adhesive electrode of the present invention, and FIG. 3 is an explanatory view showing a usage state of the adhesive electrode. 1 ... Adhesive electrode, 11 ... Electrode plate, 12 ... Adhesive layer, 110
……protrusion.

Claims (6)

[Claims] 1. A polymer having a substituted ammonio group and a carboxyl group and / or a carboxylic acid anhydride group and soluble in water and / or alcohol; having two or more glycidyl groups in one molecule, water and / or Alternatively, a medical conductive adhesive containing a glycidyl group-containing compound soluble in alcohol; and a softening agent. 2. A substituted ammonio group of the polymer is bonded to the polymer main chain through an amide bond or an ester bond; and a carboxyl group of the polymer is one of acrylic acid, methacrylic acid, crotonic acid and itaconic acid. At least one of the above, and the carboxylic acid anhydride group is derived from maleic anhydride; The pressure-sensitive adhesive according to claim 1. 3. The pressure-sensitive adhesive according to claim 1, wherein the softening agent is at least one of glycerin, diglycerin, water, and a mixture of magnesium chloride and water. 4. A medical adhesive electrode in which a conductive adhesive layer is provided on at least a part of an electrode plate, the adhesive having a substituted ammonio group and a carboxyl group and / or a carboxylic acid anhydride group. A water- and / or alcohol-soluble polymer; a water- and / or alcohol-soluble glycidyl group-containing compound having two or more glycidyl groups in one molecule; electrode. 5. A substituted ammonio group of the polymer is bonded to the polymer main chain through an amide bond or an ester bond; and a carboxyl group of the polymer is one of acrylic acid, methacrylic acid, crotonic acid and itaconic acid. The medical pressure-sensitive adhesive electrode according to claim 4, wherein the carboxylic acid anhydride group is derived from maleic anhydride. 6. The medical adhesive electrode according to claim 4, wherein the softening agent is at least one selected from glycerin, diglycerin, water, and a mixture of magnesium chloride and water.