JPH1057332A - Manufacture of bioelectrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a bioelectrode having a stable performance in a high speed and high efficiency by forming bioelectrode by adhering a not-electric conducting supporting member mounting an electrode device and a terminal on the surface of a highly electric conducting polymer gel obtained by photopolymerization of a monomer composition filled in a cavity formed on a sheet material. SOLUTION: A sheet material 1 is unwound from a roll and transported to a definite direction, a cavity 3 is continuously formed on the sheet by a thermoforming means 2 and a monomer composition liquid 4 is injected into the cavity 3 by a monomer composition injection means 14. The monomer composition 4 is polymerized by irradiating ultraviolet rays by an ultraviolet ray irradiation apparatus 5 to prepare a sticky and electric conducting polymer gel. Then a not-electric conducting supporting member 7 mounting an electrode device and a terminal 6 on the surface thereof is arranged on the surface of the sheet material 1 and is adhered to the surface of the polymer gel using the sticking property of the electric conducting polymer gel. A bioelectrode 9 is obtained by punching the sheet material 1 together with the not-electric conducting supporting member 7 to a desired shape by every cavities 3 by a punching means 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a bioelectrode for performing measurement and treatment by attaching it to the skin surface of a living body when performing electrocardiogram measurement, body fat measurement, electrical stimulation therapy, and the like. It is about.

[0002]

2. Description of the Related Art In order to measure electrocardiograms, myoelectrics, brain waves, etc.
Detects weak electric potential emitted from the human body. On the other hand, when performing body fat measurement, electrical stimulation treatment, or the like, an electric current is applied to an appropriate part of the human body. At the time of these measurements and treatments, electrodes (biological electrodes) electrically connected to external devices are attached to appropriate positions on the human body.

For example, when measuring the electrocardiogram, it is not possible to measure the electrocardiogram with high accuracy simply by bringing the element portion provided on the electrode into contact with the skin surface of a human body. The paste is made to adhere to the skin surface of the human body via a cream or paste having an electrolyte salt in water paste. However, since it is necessary to apply the cream or paste to the measurement site of the human body in advance, the application operation is troublesome, and there is an adverse effect such as giving the subject a discomfort.

[0004] Also, since one electrode is usually used repeatedly for each subject, there is a problem of hygiene and a possibility of skin infection, and further, there is a problem that the subject is uncomfortable when used. Therefore, it is desired to provide an inexpensive and disposable bioelectrode. Therefore, a water glue electrode has been proposed in which a porous member such as a sponge is fixed below an electrode element having a hook-type terminal, and a conductive paste is interposed in the sponge portion (US Pat. No. 3,817,252). Specification). However, such a conventional water-glue electrode has a drawback that the conductive paste has a large drying property when used continuously for a long period of time, which causes an increase in impedance and makes measurement impossible.

In order to improve this drawback, a similar electrode using a conductive solid gel instead of a conductive paste is also known (Japanese Patent Application Laid-Open Nos. 52-95895 and 55-9555).
81635 and 57-131428). A bioelectrode using a conventional solid gel is formed by punching a gel sheet into a predetermined shape such as a disc, and then forming the sheet into a non-conductive support member on which electrode elements and terminals are mounted (arranged) and a separate sheet. It is manufactured by sandwiching it with a resin material. For this reason, manufacturing operations such as punching of the gel portion and replacement of the gel are complicated, and high-speed and efficient stable performance due to the instability of the manufacturing equipment at the time of punching the gel portion and replacing the gel. It was difficult to obtain a bioelectrode. In addition, when the gel portion is punched, the gel is strongly attached to the punching blade, and it is necessary to frequently clean the punching blade, and there is also a drawback that the blade is greatly consumed.

[0006]

In order to solve the above-mentioned drawbacks, a backing member and an electrode in which a conductive gel is filled into a concave portion of a base member having a predetermined concave portion and then cured to form an adhesive layer in advance. A method for producing a bioelectrode to which is adhered is described in JP-A-61-259644. According to the embodiment of this publication,
Filled with a liquid conductive gel mixed with karaya rubber, glycerin and sodium chloride, left for about 1 to 2 hours or cured by heating at about 80 ° C. for 5 minutes, then to the backing member coated with adhesive An electrode element and a terminal (metal snap) are attached, and this backing member is attached to the surface of the base member to manufacture a bioelectrode.

According to this method, the complexity of manufacturing operations such as punching of a gel portion and replacement of a gel can be improved.
In manufacturing in a continuous process, there is a problem that the time required for curing is extremely long, or the base member is thermally deformed due to high-temperature heating. In addition, after filling the conductive gel into the recesses described above, a method of allowing to cool and solidify, or a crosslinking reaction by thermal polymerization as shown in Japanese Utility Model Application Laid-Open No. 60-55405, the time until solidification or curing of the gel is long. There is a problem.
In addition, in the case of thermal polymerization, a monomer-mixed liquid for forming a conductive polymer gel is heated to cause a polymerization reaction. However, since the polymerization reaction is an exothermic reaction, the temperature becomes higher and the base member is thermally deformed. There's a problem. for these reasons,
In the conventional manufacturing method, it is difficult to rapidly and efficiently manufacture a bioelectrode having stable performance by a continuous process.

An object of the present invention is to solve the above-mentioned technical problems and to provide a method for manufacturing a bioelectrode capable of manufacturing a bioelectrode having stable performance at high speed and efficiently.

[0009]

According to a method of manufacturing a bioelectrode of the present invention, a concave portion formed in a sheet member is filled with a monomer mixture containing a photopolymerization initiator and a polymerizable monomer.
Photopolymerization is performed in the recess to form a sticky conductive polymer gel, and then a non-conductive support member with an electrode element and a terminal attached to the surface of the polymer gel to form a bioelectrode. It is characterized by doing.

According to the present invention, the photocuring initiator can be added to the above-mentioned monomer-containing solution to carry out photopolymerization, whereby the gel curing reaction can be completed in a short time. Also,
In the photopolymerization, the temperature rise during the polymerization reaction can be suppressed by cooling the monomer mixture in advance. For this reason, the resin molded product having the concave portion does not have a risk of thermal deformation and does not require high thermal deformation resistance, so that the range of choice of a sheet material used as a sheet member is widened, which is advantageous in terms of cost.

The bioelectrode obtained by the method of the present invention has a structure in which a conductive polymer gel is encapsulated, so that it is easy to handle during manufacture, transportation and use. Further, by encapsulating the conductive polymer gel, a large number of bioelectrodes can be packaged together in one, so that the labor for packaging is reduced. In addition, according to the method of the present invention, since unnecessary portions do not appear in the conductive polymer gel, the yield is high, which contributes to resource saving.

In manufacturing a bioelectrode by the method of the present invention, for example, the sheet member is transferred in a certain direction, and a thermoforming step, a monomer compounding liquid injection step and a polymerization step are provided in this order along the transfer direction. Preferably, a large number of recesses are continuously formed in the sheet member in the thermoforming step while the sheet member is being transferred, and the formed recesses are sequentially filled with a monomer compounding liquid to carry out a polymerization reaction. This allows the bioelectrode to be produced with high productivity in combination with the completion of the gel curing reaction in a short time by photopolymerization. Therefore, the method of the present invention is particularly suitable for mass production.

[0013] The monomer-containing liquid is 13 to 30% by weight.
Polymerizable monomer, 16-65% by weight of water, 20-65
A liquid mixture containing a polyhydric alcohol in an amount of 2% by weight and an electrolyte salt in an amount of 2 to 15% by weight is preferable for imparting appropriate adhesion to the skin surface and high conductivity.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an outline of a continuous process for producing a bioelectrode of the present invention. In FIG. 1, reference numeral 1 denotes a sheet member, which is wound in a roll shape. The concave portion 3 is continuously formed by the thermoforming means 2 while the sheet member 1 is unreeled from the roll and transported in a certain direction. In the width direction of the sheet member 1, a plurality of recesses 3 are similarly formed by the thermoforming means 2.

The sheet member 1 is preferably a sheet member that can be thermoformed and has excellent releasability from a conductive polymer gel described later, for example, a plastic sheet such as polypropylene or polyethylene terephthalate, or paper. can do. The surface of the plastic sheet or paper may be subjected to a silicone treatment to enhance the releasability. The thickness of the sheet member 1 is about 0.1 to 1 m.
m, preferably about 0.3-0.5 mm.

The thermoforming means 2 includes, for example, a molding apparatus having a built-in heater and a male mold and a female mold which move up and down. The sheet member 1 in which the concave portions 3 are formed by thermoforming is sent to the monomer mixture liquid injection means 14, and the monomer mixture liquid 4 is injected into the concave portions 3. Next, ultraviolet rays are irradiated by the ultraviolet irradiation device 5 to the monomer mixture 4.
To polymerize to obtain a sticky conductive polymer gel.

After the polymerization, a non-conductive support member 7 having an electrode element and a terminal 6 attached thereto is disposed on the surface of the sheet member 1, and the adhesive property of the conductive polymer gel is used to make use of the adhesive property of the conductive polymer gel. Stick it on At this time, it is necessary to pay attention to the alignment between each concave portion 3 formed in the sheet member 1 and the electrode element attached to the non-conductive support member 7 and the terminal 6. The non-conductive support member 7 is bonded so that the center of the recess 3 is located at the center of the recess 3.

The non-conductive support member 7 is not particularly limited, but is preferably a film which does not have elasticity, is flexible and has relatively high waist strength for sticking the bioelectrode to the human skin surface. . As such a film, for example, the thickness of polypropylene, polyethylene terephthalate, polyvinyl chloride, polyethylene, etc. is 10 to 500 μm.
m.

After the non-conductive support member 7 is adhered, the sheet member 1 and the non-conductive support member 7 are punched out by the punching means 8 for each concave portion 3 into an arbitrary shape, whereby the bioelectrode 9 is obtained. The sheet 13 after punching is wound up and collected.
As the conductive polymer gel, any one may be used as long as it has conductivity, and has little irritation to the skin and adhesiveness, but is not particularly limited. For example, polyacrylamide, sodium polyacrylate, polyacrylic acid derivatives such as polyacrylate, polyvinylpyrrolidone, poly-N-vinylamide derivatives such as poly-N-vinylacetamide,
A conductive adhesive gel containing polyurethane or the like as a matrix and containing water, an electrolyte salt or the like can be suitably used.

The monomer mixture 4 for forming the conductive polymer gel contains a polymerizable monomer, a copolymerizable cross-linkable monomer, a neutral electrolyte salt, a wetting agent, and water. To which a photopolymerization initiator is added. Examples of the photopolymerization initiator include photoradical polymerization initiators such as acetophenone-based, benzoin ether-based, phosphorus-based, benzophenone-based, thioxanthone-based, and azo-based, and photocationic polymerization such as diazonium salts, diallyliodonium salts, and triarylsulfonium salts. Initiators and the like. The photopolymerization initiator may be used alone or as a mixture of two or more, if necessary. Further, a radical initiator or a redox initiator which does not depend on photopolymerization may be used in combination.

Examples of the crosslinkable monomer include those having two or more double bonds such as methylenebisacrylamide and polyethylene glycol diacrylate and showing copolymerizability with an acrylic acid monomer.
Examples of the wetting agent include monosaccharides, polysaccharides, polyhydric alcohols such as sorbitol, glycol, and glycerin.

FIG. 2 shows an example of the living body electrode 9 as a single electrode manufactured as described above. As shown in FIG. 2, a non-conductive support member 7 is disposed on the surface of the sheet member 1 in which the conductive polymer gel 10 is filled in the recess 3, thereby enclosing the recess 3. And the non-conductive support member 7
, An electrode element 11 and a hook-type terminal 6 which are integrally formed are attached.

When measuring an electrocardiogram or the like using the living body electrode 9, a lead wire of an electrocardiograph is connected to the terminal 6,
Next, the sheet member 1 is peeled off from the non-conductive support member 7, and the conductive polymer gel 10 is attached to a predetermined portion of the human body. 3 and 4 show another example of a bioelectrode obtained using the method of the present invention. That is, the bioelectrode 15 shown in FIG. 3 has the pressure-sensitive adhesive layer 16 provided on the inner surface of the sheet member, and has good adhesion to the skin surface when adhered to the skin surface of a human body. Such an adhesive layer 1
6 is preferably formed on the surface of the sheet member 1 in advance. In that case, it is preferable that the surface of the sheet 1 is subjected to a release treatment in order to enhance the releasability.

In the biological electrode 19 shown in FIG. 4, an electrode element portion 17 and a terminal portion 18 are integrated with the surface of the non-conductive support member 7 'instead of the electrode element 11 and the hook type terminal 6. It is formed in. The element part 17 and the terminal part 1
8 can be formed, for example, by continuous pattern printing on the surface of the non-conductive support member 7 using conductive ink. At the time of use, a lead wire (not shown) connected to the measuring device is connected to the terminal 18 for use. In FIGS. 3 and 4, the same members as those in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted.

It should be noted that the method of the present invention is not limited to the case where the above-mentioned single disk-shaped electrode is manufactured, but may be modified by changing the shape of the concave portion formed in the sheet member. A bioelectrode having a gel portion can be obtained, and a multi-electrode can also be manufactured by combining a sheet member having a plurality of recesses with a non-conductive support member having a plurality of electrode elements and terminals.

[0026]

Next, the method of the present invention will be described in detail with reference to examples and comparative examples. In the following description, “parts” means parts by weight, and “%” means weight%. Examples 1 and 2 A polypropylene sheet having a thickness of 0.5 mm was used as a sheet member, and a concave portion having a diameter of 2.5 cm and a depth of 0.2 cm was formed by thermoforming. Then, about 1 g of a monomer compound solution for a conductive polymer gel was injected and filled into the concave portion.

The monomer mixture used was composed of acrylamide as a polymerizable monomer, N, N'-methylenebisacrylamide as a copolymerizable crosslinkable monomer (crosslinking agent), and sodium chloride as a neutral salt of an electrolyte. , A predetermined amount of glycerin as a wetting agent was added to water and dissolved by stirring to obtain a monomer-containing liquid.
To this part, 0.3 part of Irgacure 184 (1-hydroxy-cyclohexyl phenylketone) manufactured by Ciba Geigy was added as a photopolymerization initiator, and the mixture was stirred and dissolved. Table 1 shows the amounts of the components constituting the monomer mixture (% with respect to the total amount of the mixture including water, and the balance is water; the same applies hereinafter).

The initial temperature of the obtained monomer mixture liquid is 4 ° C.
After adjusting to, the concave portion was filled. Then, an ultraviolet ray having an intensity of 50 milliwatt / cm ² was applied to the monomer mixture solution for 6 minutes.
Irradiation was performed for 0 second to perform a polymerization crosslinking reaction. At this time, the time (second) from the start of the ultraviolet irradiation to the start of the rapid temperature rise of the gel was measured, and at the same time, the maximum temperature during the curing reaction was measured.

On the surface of the obtained conductive polymer gel, a soft polyvinyl chloride film (non-conductive support member, thickness of 80) having electrode elements (Ag / AgCl electrodes) and hook terminals mounted thereon
μm) were laminated and punched into a circle having a diameter of 30 mm to obtain a bioelectrode. Example 3 As a polymerization initiator, 0.1 part of a photopolymerization initiator (Irgacure 184 described above) and 4 parts of a redox polymerization initiator were used.
3 parts of a 2% aqueous potassium peroxodisulfate solution and 3 parts of a 2% aqueous potassium pyrosulfite solution were mixed.
° C. A bioelectrode was obtained in the same manner as in Example 1 except that this was irradiated with ultraviolet light having an intensity of 50 mW / cm ² for 10 seconds and allowed to stand for 180 seconds to carry out a polymerization crosslinking reaction. Example 4 The procedure of Example 1 was repeated except that the initial temperature was 25 ° C.
A bioelectrode was obtained. Example 5 A 48% aqueous solution of sodium acrylate as a polymerizable monomer, N, N'-methylenebisacrylamide as a copolymerizable crosslinkable monomer, and glycerin as a wetting agent were added to water, and dissolved by stirring to prepare a monomer mixture. After preparing the monomer mixture, add a photopolymerization initiator (Irgacure 1
A bioelectrode was obtained in the same manner as in Example 1, except that 0.5 part of 84) was added. Table 1 shows the amounts of the components. Comparative Examples 1 and 2 Instead of the photopolymerization initiator (Irgacure 184 described above) used in Examples 1 and 2, 5 parts of a 4% aqueous potassium peroxodisulfate solution as a redox polymerization initiator, and 2%
After mixing 5 parts of an aqueous solution of potassium pyrosulfite and adjusting the initial temperature to 25 ° C., the mixture was heated on a heating plate maintained at 60 ° C.
A bioelectrode was obtained in the same manner as in Examples 1 and 2, except that the polymerization crosslinking reaction was carried out for 1 minute. Comparative Example 3 Karaya gum, sodium chloride, glycerin and water were stirred and mixed to obtain a conductive polymer gel compounded liquid, and about 1 g thereof was obtained.
Was filled in the concave portion of the sheet member having the concave portion. Then, at an initial temperature of 25 ° C., 1
It was solidified by heating for 0 minutes. On the upper surface of the obtained conductive polymer gel, a soft polyvinyl chloride film (a non-conductive support member, with an electrode element (Ag / AgCl electrode) and a hook terminal)
(Thickness: 80 μm), and punched into a circle having a diameter of 30 mm. Otherwise, a bioelectrode was obtained in the same manner as in Examples 1 and 2. Table 1 shows the amounts of the components. Comparative Example 4 Non-crosslinked polyacrylic acid (molecular weight: 1,000,000), sodium chloride, glycerin and water were added and mixed by stirring to obtain a conductive polymer gel compounding solution. About 1 g of the solution was placed in the concave portion of the sheet member having the concave portion. Filled. This was heated and solidified on a heating plate maintained at 66 ° C. for 30 minutes. A flexible polyvinyl chloride film (non-conductive support member, thickness: 80 μm) with an electrode element (Ag / AgCl electrode) and a hook terminal attached to the upper surface of the obtained conductive polymer gel, and a diameter of 30 mm
Punched into a circle. Otherwise, a bioelectrode was obtained in the same manner as in Examples 1 and 2. Table 1 shows the amounts of the components. Comparative Examples 5 and 6 A 48% aqueous solution of sodium acrylate as a polymerizable monomer, N, N'-methylenebisacrylamide as a copolymerizable crosslinkable monomer, sodium chloride as an electrolyte neutral salt, and glycerin as a wetting agent were used. The mixture was added to water and dissolved by stirring. To 100 parts of the obtained monomer mixture, 5.5 parts of a 4% aqueous solution of potassium peroxodisulfate and 4.0 parts of a 2% aqueous solution of potassium pyrosulfite as a redox-based polymerization initiator were added. A bioelectrode was obtained in the same manner as in Example 5, except that the mixture was mixed and dissolved by stirring.

With respect to each of the bioelectrodes obtained in Examples 1 to 5 and Comparative Examples 1 to 6, the thermal deformation state of the sheet member was observed. Furthermore, as a drying rate accompanying the polymerization of the polymer gel,
The weight of the monomer mixture before the polymerization and the weight before the non-conductive support member was attached after the polymerization were measured, and the reduced weight was expressed as a percentage. Further, 24 hours after the production, the electrode pair impedance of the bioelectrode was measured. Seven days later, the amount of residual monomer in the gel portion of the bioelectrode was measured by liquid chromatography. The electrode pair impedance was measured by the following measurement method. (Measurement of Electrode Pair Impedance) The sheet member of the prepared bioelectrode was peeled off from the gel, and the gels of the two bioelectrodes were attached to each other to form an electrode pair. The signal generator and the oscilloscope were connected by a coaxial cable, and the signal generator was adjusted so that the output voltage was 10 Vp-p, the output waveform was a sine wave, and the frequency was 10 Hz.

As shown in FIG. 5, an electrode pair 20 was connected to a resistor 21 having a resistance R of 1 MΩ. When the voltage V1 was applied from the signal generator 22 to the electrode pair, the voltage value V2 of the voltage drop by the electrode pair 20 was measured by the oscilloscope 23, and the impedance | Z | was calculated from the following relational expression. | Z | = R × V2 / (V1−V2) (where R = 1 MΩ and V1 = 10 V) The measurement results are also shown in Table 1.

[0032]

[Table 1]

[0033]

As described above, according to the present invention, there is an effect that a bioelectrode having stable performance can be produced at high speed and efficiently, and is suitable for production by a continuous process.

[Brief description of the drawings]

FIG. 1 is a process explanatory view showing a method for producing a bioelectrode of the present invention.

FIG. 2 is a cross-sectional view showing an example of a biological electrode obtained by the method of the present invention.

FIG. 3 is a cross-sectional view showing another example of the bioelectrode obtained by the method of the present invention.

4A and 4B are a cross-sectional view (FIG. 4A) and a plan view (FIG. 4B) showing still another example of a biological electrode obtained by the method of the present invention.

FIG. 5 is an explanatory diagram showing a method of measuring an electrode pair impedance.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sheet member 2 Thermoforming means 3 Concave part 4 Monomer compound liquid 5 Ultraviolet irradiation device 7 Non-conductive support member 9 Bioelectrode 10 Conductive polymer gel 11 Electrode element 15 Bioelectrode 19 Bioelectrode

Claims (3)

[Claims] 1. A concave portion formed in a sheet member is filled with a monomer compounding liquid containing a photopolymerization initiator and a polymerizable monomer, and photopolymerization is performed in the concave portion to form a sticky conductive polymer gel. None. Then, a non-conductive support member having an electrode element and a terminal attached thereto is attached to the surface of the polymer gel to form a bioelectrode. 2. The method according to claim 1, wherein the sheet member is transferred in a fixed direction, and a thermoforming step, a monomer compounding liquid injection step and a polymerization step are provided in this order along the transfer direction. 2. The method for producing a bioelectrode according to claim 1, wherein a large number of recesses are continuously formed in the sheet member in the step, and the formed recesses are sequentially filled with a monomer compounding solution to carry out a polymerization reaction. 3. The method according to claim 1, wherein the monomer mixture liquid is 13 to 30% by weight.
Polymerizable monomer, 16 to 65% by weight of water, 20 to 65%
The method for producing a bioelectrode according to claim 1, wherein the mixture is a liquid mixture containing a wetting agent of 2 wt% and an electrolyte salt of 2 to 15 wt%.