JPH0924030A - Conductive composition for bio-electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive composition for a bio-electrode, by which the impedance between an electrode and the skin can be reduced. SOLUTION: A gel conductive composition for a bio-electrode has a function of connecting a living body and an electrode element to each other electrically and physically and is composed of at least the following components: 1. a radical polymerized unsaturated compound, 2. one plasticizer of polyatomic alcohol, amine and ethers, 3. a moiturizer for assisting and promoting the physiological moisture keeping function of the horny layer of the skin, 4. a polymerization initiator, and 5. a crosslinking agent. At the time of using the above composition, the water content of the horny layer is increased by the moiturizer to lower the impedance to the skin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive composition which is interposed between skin and an electrode element when a bioelectrode is attached.

[0002]

2. Description of the Related Art A bioelectrode is composed of an electrode element made of silver, silver / silver chloride, carbon, or the like, and some electrically conductive composition that connects the electrode element and the skin. It is used by being mounted on the body surface when deriving a bioelectric phenomenon such as an electrogram or applying an electrical stimulus to a living body.

The outer layer of normal human skin has a layer called keratin, which protects the living body from invasion of various external factors. When the skin is exposed to dry air, water is lost from the stratum corneum, or the water content in the stratum corneum decreases with age,
Electrically, the resistance of the stratum corneum increases. In addition, the skin surface is not flat, but has irregularities and is curved and has a complicated shape.

When the electrode element is brought into direct contact with the skin surface of the stratum corneum that is deficient in water in this manner, the contact between the electrode element and the skin is apt to be hindered, and the effective contact area is reduced, so that the contact resistance increases, Furthermore, since the resistance of the stratum corneum is high as described above, the overall electric resistance is also high. For this reason, noise is likely to be mixed in the derived bioelectric signal, and recording may become unstable, and sometimes recording may not be possible. Further, when an electrical stimulus is applied from the body surface via the electrode, the contact surface has a high resistance and a high current density, which may cause damage to the living body such as burns.

In order to solve these problems, liquid electrodes, jelly-like or gel-like conductive compositions are generally used in bioelectrodes for the purpose of reducing the skin resistance between the living body and the electrodes. These conductive compositions contain a large amount of water and NaC.
It contains electrolytes such as 1 and KCl, which act to reduce skin resistance by being absorbed from the outside of the skin into the stratum corneum of the skin. However, these conductive compositions are
Due to its component properties, it has low viscosity and fluidity by itself, so that it is difficult to stably hold it between the electrode element and the skin for a long time. Therefore, a storage space for holding the conductive composition in the electrode element or a holding means such as a sponge is required. Furthermore, an adhesive tape is required to fix the electrode element on the body surface. However, when the adhesive tape is used, mechanical damage to the skin is caused when the electrode element is repeatedly attached and detached.

When an electrode element is attached to a body surface through such a conductive composition for a long time and used in ICU, Holter electrocardiogram measurement, etc., the conductive composition is pressed by the body movement or the outside, and mechanically. Receive a load. For this reason, the conductive composition leaks to the periphery of the electrode element and peels off the electrode, or the outflow of the conductive composition makes the contact between the electrode element and the skin unstable, making it impossible to record a biological signal.

Further, in such a conductive composition, water evaporates and dries during use, so that the skin resistance becomes high and the recording of the biosignal becomes unstable. Further, when water is evaporated from the conductive composition, the concentration of chlorine ions in the conductive composition is increased and skin irritation occurs. Furthermore, these conductive compositions remain on the skin even after the electrode element is removed, which causes skin irritation.

Further, the electrodes include an electrode that can be repeatedly used and a so-called disposable electrode that is used once and then discarded. The former applies the conductive composition to the skin just before use, and most of the latter has the electrode already filled with or incorporated with the conductive composition so that it can be easily put on. For this reason, the latter electrode needs to have a structure in which the conductive composition does not dry until just before use, and needs to be hermetically sealed so that the conductive composition does not dry during storage after production. Therefore, the latter electrode has a complicated structure as a whole in consideration of its use and storage.

At present, as a solution to these problems with the liquid conductive composition, a solid gel conductive composition having no fluidity and being soft and having an adhesive force has been developed (for example, Japanese Patent Publication No. 62-62). -44933, 63
-43646, Japanese Patent Publication No. 63-59334, Japanese Patent Fair 2-3
2892). Since the solid gel-like conductive composition can give an adhesive force to itself, it is possible to omit the fixing adhesive tape which was indispensable for the electrode using the liquid-like conductive composition. It is convenient to use.

However, the greatest drawback of this type of solid gel conductive composition is that the impedance between the electrode and the skin cannot be sufficiently reduced.

The impedance reduction of the stratum corneum in this solid gel conductive composition is carried out by absorbing its own water and electrolytes such as KCl and NaCl from the outside of the skin into the stratum corneum. Generally, there are two types of water in a solid gel: free water that can move freely and bound water that cannot move freely.
Free water plays a large role in reducing the impedance of the stratum corneum, and the greater the content of free water, the more effective it is. However, increasing the content of this free water. Water oozes out on the surface of the solid gel, and further, the function peculiar to the solid gel is lost, such as loss of tackiness.

[0012]

Polyhydric alcohols such as glycerin and propylene glycol are often added as plasticizers to conventional solid gels, but these plasticizers are nonionic substances. It is not responsible for conductivity, and is a cause of high electric resistance of the conductive composition itself.

To reduce the electric resistance, KCl or NaCl is used.
It is also necessary to add water such as electrolyte to smooth the movement of the electrolyte. However, if the water content is increased in order to make the movement of the electrolyte smooth, the adhesive force is lost as described above, and the electrolyte becomes unusable. Furthermore, if excessive moisture or electrolyte is percutaneously absorbed from outside the body, skin disorders such as rash will occur. Therefore, the water content has an upper limit, and the body skin impedance cannot be lowered sufficiently.

The object of the present invention is to increase the water content or K
It is an object of the present invention to provide a conductive composition for a bioelectrode, which is hypoallergenic and can increase the amount of water containing keratin and reduce the impedance between the electrode and the skin without relying on an electrolyte such as Cl or NaCl.

[0015]

The invention according to claim 1 is
A gel-like conductive composition for a bioelectrode, which has a function of electrically and physically connecting a living body and an electrode element, and at least 1. 1. An organic polyelectrolyte having a free polymerizable group, 2. 2. A plasticizer selected from polyhydric alcohols, amines, and ethers. 3. A moisturizer that assists and enhances the physiological moisturizing function of the stratum corneum of the skin. Polymerization initiator, 5. It is composed of each component of the crosslinking agent.

The invention according to claim 2 is the conductive composition for a bioelectrode according to claim 1, wherein the unsaturated compound is acrylic acid, methacrylic acid, crotonic acid, itaconic acid, acrylamide, methacrylamide, 2-acrylamide. −
It is characterized by being any one of an acrylic acid-vinylpyrrolidone mixture, a vinyl acetate-ethylene mixture, and a vinyl acetate-dioctyl maleate mixture, such as 2-methylpropanesulfonic acid and salts thereof.

The invention according to claim 3 is the invention according to claim 1 or 2.
In the conductive composition for a bioelectrode described, the plasticizer is glycerin, diglycerin, propylene glycol, butylene glycols, amylene glycols, 1.5-pentanediol, trimethylolethane, dipropylene glycol, polypropylene glycol, Polyethylene glycol, polyoxyethylene, polyoxypropylene glycol, polyoxypropylene butyl ether,
Alkyl sulfate triethanolamine, diethanolamine, triethanolamine, aminoalkyl propanol, alkyl trimethyl ammonium chloride, fatty acid diethanol amide, sorbitan alkyl ether,
One of sorbitan polyoxyethylene alkyl ether and dimethyl alkyl petaine, or a combination of two or more thereof is characterized.

According to a fourth aspect of the present invention, in the conductive composition for a bioelectrode according to the first to third aspects, the moisturizing agent is urea, sodium pyrrolidonecarboxylate, sodium lactate, potassium pyrrolidonecarboxylate, or potassium lactate. Or a combination of two or more thereof.

According to a fifth aspect of the present invention, in the conductive composition for a bioelectrode according to the first to third aspects, the moisturizing agent is 1 wt% to 25 wt% urea, 1 wt% to 50 wt% pyrrolidone. Sodium carboxylate, 1 wt% to 40 wt% sodium lactate, 1 wt% to 50 wt% potassium pyrrolidonecarboxylate, and 1 wt% to 50 wt% potassium lactate.

According to a sixth aspect of the present invention, in the conductive composition for a bioelectrode according to any of the first to fifth aspects, the polymerization initiator is a photopolymerization initiator for initiating photopolymerization or heat-induced polymerization. It is characterized by being a thermal polymerization initiator to be started.

The invention according to claim 7 is the conductive composition for a bioelectrode according to claim 6, wherein the photopolymerization initiator is benzyl dimethyl ketal, 1-hydroxy-cyclohexyl-phenyl-ketone, 1-hydroxy-cyclohexyl. A eutectic mixture of phenyl-ketone and benzophenone, 2
-Methyl-1- [4- (methylthio) phenyl] -2-
Monforinopropanone-1,2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2 -Hydroxy-2-methyl-
Mixture of 1-phenyl-propan-1-one and 2.4.6-trimethylbenzoyldiphenyl-phosphine oxide, mixture of 2-hydroxy-2-methyl-1-phenylpropan-1-one and bisacylphosphine oxide , 1- [4- (2-hydroxyethoxy)-
Phenyl] -2hydroxy-2-methyl-1-propan-1-one or bis (cyclopentadienyl) -bis (2.6-difluoro-3- (pyr-1-yl) titanium. Is characterized by.

The invention according to claim 8 is the conductive composition for a bioelectrode according to claim 6, wherein the thermal polymerization initiator is azobisisobutyronitrile, benzoylperoxide, lauroylperoxide, methylethylketoneperoxide. , Cyclohexanone peroxide, t-butyl hydroperoxide, di-t-butylperoxide, di-t
-Amylper-oxide, dicumylper-oxide or t-butylper-benzoate.

The invention according to claim 9 is the conductive composition for a bioelectrode according to any one of claims 1 to 8, wherein the cross-linking agent is NN ′ methylenebisacrylamide, ethylene glycol dimethacrylate, polyethylene glycol 400. Diacrylate, diethylene glycol diacrylate, 1.3-butanediol diacrylate, 1.
4-butanediol diacrylate, 1.6-hexanediol diacrylate, neopentyl glycol diacrylate, hydroxypivalate neopentyl glycol diacryl, trimethylolpropane toluacrylate, pentaerythritol toluacrylate, dipentaerythritol hexaacrylate, tri It is characterized by being one of methylolpropane trimethacrylate.

The conductive composition according to claim 1 has a moisturizing agent. When the conductive composition is in contact with the skin, the moisturizer acts on the stratum corneum to assist and enhance the physiological moisturizing function of the stratum corneum. Therefore, when the electrode element is attached via this conductive composition, the impedance between the electrode element and the skin is lowered due to the water appearing in the stratum corneum.

In the conductive composition according to the second aspect, the organic polyelectrolytes, which are easily polymerized with each other, are components, so that the polymerization reaction is easily performed.

The conductive composition according to claim 3 has suitable plasticity.

In the electroconductive composition according to claim 4, the water content of the stratum corneum remarkably increases during use.

In the electrically conductive composition according to the fifth aspect, gelling is not impaired due to the amount of the moisturizing agent during the production.

The conductive composition according to claim 6 initiates a polymerization reaction by light or heat by a light or heat polymerization initiator during production.

In the production of the conductive composition according to the seventh aspect, the initiation of the polymerization reaction by light is easily carried out.

In the production of the conductive composition according to the eighth aspect, the initiation of the polymerization reaction by heat is easily carried out.

A cross-linking reaction is easily carried out during production of the conductive composition according to the ninth aspect.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1; 20% by weight of acrylic acid, 0.08% by weight of NN ′ methylenebisacrylamide, 0.08% by weight of benzyl dimethyl ketal, 45.84% by weight of glycerin, 12% by weight of KOH, 12% by weight of water, urea 10% by weight
Add and dissolve uniformly. This is φ28 mm, thickness 1.
It is filled in a 5 mm silicon mold and subjected to cross-linking polymerization by irradiation for 15 seconds using an ultraviolet irradiation device (using a high-pressure mercury lamp, output 450 W, irradiation distance 180 mm) to obtain an adhesive solid gel-like conductive composition.

Embodiment 2; 20% by weight of acrylic acid and 0.08% by weight of NN ′ methylenebisacrylamide,
Benzyl dimethyl ketal 0.08% by weight, glycerin 4
3.84% by weight, KOH 12% by weight, water 12% by weight, pyrrolidonecarboxylic acid (PCA) soda 12% by weight are added and uniformly dissolved. This is φ28mm, thickness 1.5m
1 m using a UV irradiation device (using a high-pressure mercury lamp, output 450 W, irradiation distance 180 mm)
Crosslinking polymerization is performed by irradiation for 5 seconds to obtain a solid gel-like conductive composition having tackiness.

Embodiment 3; 20% by weight of acrylic acid and 0.08% by weight of NN ′ methylenebisacrylamide,
Benzyl dimethyl ketal 0.08% by weight, glycerin 4
3.84% by weight, KOH 12% by weight, water 12% by weight, sodium lactate 12% by weight are added and uniformly dissolved. This is φ
Filled in a silicon mold of 28 mm and thickness of 1.5 mm, cross-linking polymerization was carried out by irradiation for 15 seconds with an ultraviolet irradiation device (using a high pressure mercury lamp, output 450 W, irradiation distance 180 mm), and a solid gel-like conductivity with adhesion. A sex composition is obtained.

Embodiment 4; 17% by weight of acrylic acid and 0.07% by weight of NN ′ methylenebisacrylamide,
Benzyl dimethyl ketal 0.07% by weight, glycerin 4
2.86% by weight, KOH 10% by weight, water 10% by weight, urea 20% by weight are added and uniformly dissolved. This is φ28m
m, 1.5 mm thick silicon mold filled with ultraviolet irradiation device (high pressure mercury lamp used, output 450 W, irradiation distance 180
(mm) to perform cross-linking polymerization by irradiation for 15 seconds to obtain a sticky solid gel conductive composition.

Embodiment 5: 18% by weight of acrylic acid and 0.08% by weight of NN ′ methylenebisacrylamide,
Benzyl dimethyl ketal 0.08% by weight, glycerin 4
4.84% by weight, KOH 11% by weight, water 11% by weight, pyrrolidonecarboxylic acid (PCA) soda 15% by weight are added and uniformly dissolved. This is φ28mm, thickness 1.5m
1 m using a UV irradiation device (using a high-pressure mercury lamp, output 450 W, irradiation distance 180 mm)
Crosslinking polymerization is performed by irradiation for 5 seconds to obtain a solid gel-like conductive composition having tackiness.

Embodiment 6; 18% by weight of acrylic acid and 0.08% by weight of NN ′ methylenebisacrylamide,
Benzyl dimethyl ketal 0.08% by weight, glycerin 4
4.84% by weight, KOH 11% by weight, water 11% by weight, sodium lactate 15% by weight are added and uniformly dissolved. This is φ
Filled in a silicon mold of 28 mm and thickness of 1.5 mm, cross-linking polymerization was carried out by irradiation for 15 seconds with an ultraviolet irradiation device (using a high pressure mercury lamp, output 450 W, irradiation distance 180 mm), and a solid gel-like conductivity with adhesion. A sex composition is obtained.

Embodiment 7: 20% by weight of acrylic acid and 0.08% by weight of NN ′ methylenebisacrylamide,
Benzyl dimethyl ketal 0.08% by weight, glycerin 4
5.84% by weight, KOH 12% by weight, water 12% by weight, pyrrolidonecarboxylic acid (PCA) potassium 10% by weight,
Dissolve uniformly. This was filled in a silicon mold having a diameter of 28 mm and a thickness of 1.5 mm, and the ultraviolet irradiation device (using a high-pressure mercury lamp, output 450 W, irradiation distance 180 mm) was used for 15
Crosslinking polymerization is carried out by irradiation for a second to obtain a solid gel-like conductive composition having tackiness.

Embodiment 8: 0.08% by weight of NN ′ methylenebisacrylic acid, 0.08% by weight of benzyldimethylketal and 4% of glycerin in 20% by weight of acrylic acid.
5.84% by weight, KOH 12% by weight, water 12% by weight, potassium lactate 10% by weight are added and uniformly dissolved. This is φ2
Filled in a silicon mold with a thickness of 8 mm and a thickness of 1.5 mm, an ultraviolet irradiation device (using a high pressure mercury lamp, output 450 W, irradiation distance 1
(80 mm) to carry out cross-linking polymerization by irradiation for 15 seconds to obtain a solid gel-like conductive composition having stickiness.

Embodiment 9: 16% by weight of acrylic acid and 0.07% by weight of NN ′ methylenebisacrylamide,
Benzyl dimethyl ketal 0.07% by weight, glycerin 3
Add 8.86% by weight, KOH 10% by weight, water 10% by weight, urea 25% by weight and dissolve uniformly. This is φ28m
m, 1.5 mm thick silicon mold filled with ultraviolet irradiation device (high pressure mercury lamp used, output 450 W, irradiation distance 180
(mm) to perform cross-linking polymerization by irradiation for 15 seconds to obtain a sticky solid gel conductive composition.

Embodiment 10: 22% by weight of acrylic acid
N-N 'methylenebisacrylamide 0.09% by weight, benzyldimethyl ketal 0.09% by weight, glycerin 25.82% by weight, KOH 13% by weight, water 13% by weight, pyrrolidonecarboxylic acid (PCA) soda 26% by weight
Add and dissolve uniformly. This is φ28 mm, thickness 1.
It is filled in a 5 mm silicon mold and subjected to cross-linking polymerization by irradiation for 15 seconds using an ultraviolet irradiation device (using a high-pressure mercury lamp, output 450 W, irradiation distance 180 mm) to obtain an adhesive solid gel-like conductive composition.

Comparative Example 1 22% by weight of acrylic acid and N-
N'methylenebisacrylamide 0.09% by weight, benzyl dimethyl ketal 0.09% by weight, glycerin 51.
82% by weight, KOH 13% by weight and water 13% by weight are added and uniformly dissolved. This is φ28mm, thickness 1.5m
1 m using a UV irradiation device (using a high-pressure mercury lamp, output 450 W, irradiation distance 180 mm)
Crosslinking polymerization is performed by irradiation for 5 seconds to obtain a conductive composition having tackiness.

Comparative Example 2 17% by weight of acrylic acid and N-
N'methylenebisacrylamide 0.07% by weight, benzyl dimethyl ketal 0.07% by weight, glycerin 42.
86% by weight, KOH 10% by weight, water 30% by weight,
Dissolve uniformly. This was filled in a silicon mold having a diameter of 28 mm and a thickness of 1.5 mm, and the ultraviolet irradiation device (using a high-pressure mercury lamp, output 450 W, irradiation distance 180 mm) was used for 15
Crosslinking polymerization is carried out by irradiation for a second to obtain a conductive composition having tackiness.

FIG. 1 shows Embodiments 1 to 10 and Comparative Examples 1 and 2.
The composition and characteristics of each of the conductive compositions of are shown below. In the column of properties, gelation means whether or not it is in a gel state suitable for this kind of conductive composition, and a suitable one is marked with a circle, and a different one is marked with a cross. The room temperature weight change means the degree of evaporation of water when each composition is left indoors for a certain period of time, and in this example, shows the change in weight% after 24 hours. The adhesive strength to skin was measured by making each conductive composition into a strip shape of 20 mm (a strip shape having a thickness of 1.5 mm and a width of 20 mm using a silicon mold different from the above silicon mold for this characteristic test). (Manufacturing) means the force required for sticking to the skin and peeling it off, g /
Shown in 20 mm. The water content of the stratum corneum means the water content after each conductive composition has been adhered to the skin for a certain period of time and then peeled off, and the conductance (unit is μ
S). In this example, the value is a value measured after 30 minutes after 30 minutes after being adhered for 1 hour. The skin impedance is
As shown in FIG. 4, it is an impedance value when the electrode element 2 is attached to the skin via each conductive composition 1 and used as a part of the electrode. In this example, the value is at a frequency of 10 Hz and is shown by kΩ.

According to FIG. 1, the first to tenth embodiments are in a proper gel form, and even if they are left indoors, the water does not evaporate, the adhesion to the skin is large, and the amount of water in the stratum corneum is large. ,
The impedance to skin is extremely small. Embodiment 1
10 has characteristics superior to those of Comparative Examples 1 and 2. That is, the composition containing a moisturizer is very suitable as a conductive composition for a bioelectrode as compared with a composition containing no moisturizer.

FIG. 2 shows the result of an experiment conducted to confirm what the weight percent of the moisturizer is to be suitable as the conductive composition for a bioelectrode. Each of prototypes S1 to S15 uses the components in the weight% shown in the drawing, and the first embodiment is shown.
It was created in the same manner as 10 to 10. According to this, when the moisturizing agent is urea, 1% by weight to 25% by weight,
In the case of sodium pyrrolidone carboxylic acid, 1% by weight to 5%
0% by weight, 1% by weight to 40% by weight for sodium lactate and 1% by weight for potassium pyrrolidonecarboxylate
It has been found that 50% by weight and 1% by weight to 50% by weight in the case of potassium lactate are suitable. The reason why the appropriate weight% range of each moisturizing agent is set as above is that the effect of using the moisturizing agent does not appear when the content is below the range, and proper gelation cannot be obtained when the content exceeds the range. is there.

In the first to tenth embodiments shown in FIG. 1 and the prototypes S1 to S15 shown in FIG. 2, the unsaturated compound is acrylic acid which is a free radical polymerizable unsaturated compound. Methacrylic acid, crotonic acid, itaconic acid, acrylamide, methacrylamide, and 2-acrylamide-2, which are also unsaturated compounds capable of free radical polymerization.
Polymers such as methyl propane sulfonic acid, salts thereof,
Acrylic acid-vinylpyrrolidone copolymer, vinyl acetate-
Pyrrolidone copolymer, vinyl acetate-ethylene copolymer,
The same action and effect can be obtained with any of the vinyl acetate-dioctyl maleate copolymers.

Similarly, the plasticizer was glycerin, but instead of this, diglycerin, propylene glycol, butylene glycols, amylene glycols,
1.5-pentanediol, trimethylolethane, dipropylene glycol, polypropylene glycol, polyethylene glycol, polyoxyethylene, polyoxypropylene glycol, polyoxypropylene butyl ether, triethanolamine alkylsulfate, diethanolamine, triethanolamine, aminoalkyl propanol , Alkyltrimethylammonium chloride, fatty acid diethanolamide, sorbitan alkyl ether, sorbitan polyoxyethylene alkyl ether, dimethylalkyl petaine, or a combination of two or more of them, the same action,
Has an effect.

Similarly, the polymerization initiator was benzyl dimethyl ketal, which is a photopolymerization initiator for initiating photopolymerization. Instead of this, 1-hydroxy-cyclohexyl-
Phenyl-ketone, 1-hydroxy-cyclohexyl-
A eutectic mixture of phenyl-ketone and benzophenone, 2-
Methyl-1- [4- (methylthio) phenyl] -2-monfolinopropane-1,2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2-hydroxy-2 -Methyl-1-phenyl-propan-1-one and a mixture of 2.4.6-trimethylbenzoyldiphenyl-phosphine oxide, 2-
Hydroxy-2-methyl-1-phenylpropane-1-
A mixture of on and bisacylphosphine oxide, 1
-[4- (2-hydroxyethoxy) -phenyl] -2
The same action is obtained with any of hydroxy-2-methyl-1-propan-1-one and bis (cyclopentadienyl) -bis (2.6-difluoro-3- (pyr-1-yl) titanium. The effect is obtained.

In each of the above examples, the composition was produced by photopolymerization. However, the composition can be produced by heat polymerization. The polymerization initiator in this case is azobisisobutyronitrile, benzoylperoxide, lauroylperoxide, methylethylketoneperoxide, cyclohexanoneperoxide, t-butylhydroperoxide, di-t-butylperoxide, diester. -T
It may be any of amyl per-oxide, dicumyl per oxide, and t-butyl per-benzoate. The composition produced by such polymerization can also obtain the same effects as the composition produced by the polymerization by light.

Similarly, the cross-linking agent was NN'methylene bisacrylamide, which is a polyradically unsaturated material capable of free radical polymerization, but instead it was also a polylabile unsaturated material capable of free radical polymerization. Certain ethylene glycol dimethacrylate, polyethylene glycol 400 diacrylate, diethylene glycol diacrylate, 1.3-butanediol diacrylate, neopentyl glycol diacrylate, hydroxypivalate neopentyl glycol diacryl, trimethylolpropane toluacrylate, pentaerythritol. Similar effects can be obtained with any of tol acrylate, dipentaerythritol hexaacrylate, and trimethylolpropane trimethacrylate.

Similarly, the moisturizers were potassium lactate, sodium lactate, sodium pyrrolidonecarboxylate, and potassium pyrrolidonecarboxylate, which function as plasticizers and reduce skin impedance. However, similar effects can be obtained by adding lactic acid or pyrrolidonecarboxylic acid instead of them. Whichever one is used, FIG.
This is because the same substance will be present after the addition as shown in FIG. Although the moisturizing agent is one kind in each of the above-mentioned embodiments, the same action and effect can be obtained even if two or more kinds of moisturizing agents are combined.

A cardiac defibrillation device is sometimes used to treat ventricular fibrillation. In such a case, it is necessary to record the electrocardiogram at the same time and confirm the effect immediately after the treatment. However, the electrocardiogram may not be recorded accurately depending on the material of the electrode element and the conductive composition used at this time. The reason for this is that when a cardiac defibrillator is used, a partial current flows between the electrodes for electrocardiogram, a polarization voltage is generated, and an excessive and rapid change in the DC voltage occurs temporarily. In order to solve this problem, it is necessary to use a non-polarizing voltage such as Ag / AgCl or AgCl for the electrode element. Further, in order to bring out the effect of the non-polarizing property, the conductive composition in contact with the electrode element must contain Cl ion which is a common ion with the electrode element. As shown in FIG. 3, it can be seen that the present conductive composition is also sufficiently effective in reducing the generation of the polarization voltage when KCl is contained. FIG. 3 shows the composition of the fourth embodiment and the composition of the eleventh embodiment obtained by adding 0.7% by weight of KCl to all the components constituting the composition of the fourth embodiment. Each shows the polarization voltage generated when a current of 0.5 μA is applied.

[0055]

According to the invention of claim 1, when the moisturizer penetrates into the stratum corneum of the skin, moisture in the tissue is bound to the moisturizer,
Increases the moisturizing properties of the entire stratum corneum. This makes it possible to increase the amount of water in the stratum corneum of the skin without forcibly absorbing water from the outside. When the amount of water in the stratum corneum increases, the electrical resistance of the stratum corneum decreases, so that the skin impedance of the electrode can be suppressed low.

Since the moisturizing agent functions to reduce the impedance to the skin in this way, the amount of water added for the purpose of reducing the impedance to the skin can be reduced. Therefore, the present electrically conductive composition can avoid problems such as loss of adhesive force due to water leaching, and skin damage caused by the skin percutaneously absorbing excess water from outside the body. At the same time, the conductive composition originally has a low water content, and due to the moisturizing property of the moisturizing agent,
Evaporation of water during storage or use can be suppressed, and performance deterioration as a conductive composition can be avoided.

According to the second aspect of the invention, the polymerization reaction is easily carried out during the production.

According to the third aspect of the invention, the product can easily be made plastic.

According to the invention of claim 4, since a moisturizer having a function of imparting tackiness is added, the adhesion to skin is improved. Further, the adhesion to skin can be easily controlled by changing the addition amount of this moisturizing agent.

Further, since sodium pyrrolidone carboxylic acid, potassium pyrrolidone carboxylic acid, potassium lactate, sodium lactate and the like are ionic substances, electrolytes such as NaCl and KCl are used as compared with the case where a nonionic polyhydric alcohol is added. The conductivity of the conductive composition itself can be increased without adding it. Further, since these moisturizers are substances originally present in the stratum corneum of the skin, there is little risk of skin irritation even if added.

According to the invention of claim 5, in addition to the effect of the invention of claim 4, there is an effect that the product does not deviate from the range of gelation.

According to the invention of claim 6, there is an effect that the polymerization reaction is efficiently carried out during the production.

According to the invention of claim 7, there is an effect that the polymerization reaction by light is efficiently carried out during the production.

According to the invention of claim 8, there is an effect that the polymerization reaction by heat is efficiently carried out during the production.

According to the ninth aspect of the invention, there is an effect that the crosslinking reaction is efficiently carried out during the production.

[Brief description of drawings]

FIG. 1 is a diagram showing the composition and characteristics of each of the conductive compositions of Embodiments 1 to 10 and Comparative Examples 1 and 2.

FIG. 2 is a diagram showing the composition and characteristics of prototypes prepared by changing the types of moisturizers and the weight% of each moisturizer.

FIG. 3 is a diagram showing the relationship between the weight% of KCl contained to reduce the polarization voltage generated between electrodes and the polarization voltage.

FIG. 4 is a diagram showing a configuration of an electrode using the conductive composition of any of Embodiments 1 to 10 and Comparative Examples 1 and 2.

FIG. 5 is a view for explaining states before and after the addition of a salt as a moisturizer.

FIG. 6 is a view for explaining states before and after addition of an acid moisturizer.

[Explanation of symbols]

 1 Conductive composition 2 Electrode element

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08L 33/02 LHR C08L 33/02 LHR 33/26 LHV 33/26 LHV // A61N 1/04 A61N 1/04

Claims (9)

[Claims] 1. A gel-like conductive composition for a bioelectrode, which has a function of electrically and physically connecting a living body and an electrode element and is composed of at least the following components. 1. Unsaturated compound capable of free radical polymerization 1. 2. A plasticizer selected from polyhydric alcohols, amines and ethers. 3. A moisturizer that assists and enhances the physiological moisturizing function of the stratum corneum of the skin. Polymerization initiator 5. Cross-linking agent 2. Unsaturated compounds include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, acrylamide, methacrylamide, 2-acrylamido-2-methylpropanesulfonic acid, salts thereof, acrylic acid-vinylpyrrolidone mixture, acetic acid. The conductive composition for a bioelectrode according to claim 1, which is one of a vinyl-ethylene mixture and a vinyl acetate-dioctyl maleate mixture. 3. The plasticizer is glycerin, diglycerin, propylene glycol, butylene glycol, amylene glycol, 1.5-pentanediol, trimethylolethane, dipropylene glycol, polypropylene glycol, polyethylene glycol, polyoxyethylene. , Polyoxypropylene glycol, polyoxypropylene butyl ether, triethanolamine alkylsulfate, diethanolamine, triethanolamine,
2. An aminoalkyl propanol, an alkyl trimethyl ammonium chloride, a fatty acid diethanolamide, a sorbitan alkyl ether, a sorbitan polyoxyethylene alkyl ether, a dimethyl alkyl petaine, or a combination of two or more thereof. Alternatively, the conductive composition for a bioelectrode according to the item 2. 4. The humectant is any one of urea, sodium pyrrolidonecarboxylate, sodium lactate, potassium pyrrolidonecarboxylate, potassium lactate, or a combination of two or more thereof. 4. The conductive composition for a bioelectrode according to any one of 1 to 3. 5. A humectant is 1% to 25% by weight of urea,
1% to 50% by weight of sodium pyrrolidonecarboxylate,
4. Any one of 1 wt% to 40 wt% sodium lactate, 1 wt% to 50 wt% potassium pyrrolidone carboxylic acid, and 1 wt% to 50 wt% potassium lactate. An electrically conductive composition for a biological electrode according to claim 1. 6. The bioelectrode according to any one of claims 1 to 5, wherein the polymerization initiator is a photopolymerization initiator that initiates polymerization by light or a thermal polymerization initiator that initiates polymerization by heat. Conductive composition for use. 7. The photopolymerization initiator is benzyl dimethyl ketal, 1-hydroxy-cyclohexyl-phenyl-ketone, a eutectic mixture of 1-hydroxy-cyclohexyl-phenyl-ketone and benzophenone, 2-methyl-1-.
[4- (Methylthio) phenyl] -2-monforinopropanone-1,2-benzyl-2-dimethylamino-1
-(4-morpholinophenyl) -butanone-1,2-
Hydroxy-2-methyl-1-phenyl-propane-1
-One, 2-hydroxy-2-methyl-1-phenyl-
A mixture of propan-1-one and 2.4.6-trimethylbenzoyldiphenyl-phosphine oxide, 2-
Hydroxy-2-methyl-1-phenylpropane-1-
A mixture of on and bisacylphosphine oxide, 1
-[4- (2-hydroxyethoxy) -phenyl] -2
One of hydroxy-2-methyl-1-propan-1-one and bis (cyclopentadienyl) -bis (2.6-difluoro-3- (pyr-1-yl) titanium. The conductive composition for a bioelectrode according to claim 6. 8. The thermal polymerization initiator is azobisisobutyronitrile, benzoylperoxide, lauroylperoxide, methylethylketoneperoxide, cyclohexanoneperoxide, t-butylhydroperoxide, di-t-butylperoxide. The conductive composition for a bioelectrode according to claim 6, which is any one of oxide, di-t-amylpa-oxide, dicumylpa-oxide, and t-butylpa-benzoate. 9. The cross-linking agent is NN ′ methylene bisacrylamide, ethylene glycol dimethacrylate, polyethylene glycol 400 diacrylate, diethylene glycol diacrylate, 1.3-butanediol diacrylate, 1.4-butanediol diacrylate,
Any one of 1.6-hexanediol diacrylate, neopentyl glycol diacrylate, hydroxypivalic acid ester neopentyl glycol diacrylic, trimethylolpropane toluacrylate, pentaerythritol toluacrylate, dipentaerythritol hexaacrylate, and trimethylolpropane trimethacrylate. The conductive composition for a bioelectrode according to any one of claims 1 to 8, wherein