JP7207027B2 - Bioelectrode and biosignal measuring device - Google Patents

Description

The present invention relates to bioelectrodes and biosignal measuring devices.

Biomedical electrodes are known as members for detecting biomedical signals.
For example, Patent Literature 1 discloses a bioelectrode made of an elastic body in which metal particles are contained in resin, and is used in close contact with the human body.
Further, Patent Document 2 discloses a bioelectrode in which carbon fibers are contained in ABS resin (acrylonitrile-butadiene-styrene copolymer resin).

JP 2018-11931 A JP-A-2018-33769

An object of the present invention is to provide a biomedical contact portion that is in contact with a living body, and that has a conductive biomedical contact portion containing a rubber material and one kind of carbon black. It is to provide a bioelectrode to measure.

Means for achieving the above objects include the following aspects.
<1>
1. A bioelectrode having a biocontact portion that is in contact with a living body and that is conductive and contains a rubber material and two or more kinds of carbon black having different DBP oil absorptions.
<2>
The living body contact portion contains, as the two or more types of carbon black, a first carbon black having a DBP oil absorption of less than 200 cm ³ /100 g and a second carbon black having a DBP oil absorption of 200 cm ³ /100 g or more. The bioelectrode according to <1> containing.
<3>
The bioelectrode according to <2>, wherein the DBP oil absorption difference (absolute value) between the first carbon black and the second carbon black is 70 cm ³ /100 g or more and 400 cm ³ /100 g or less.
<4>
The bioelectrode according to <3>, wherein the DBP oil absorption difference (absolute value) between the first carbon black and the second carbon black is 100 cm ³ /100 g or more and 300 cm ³ /100 g or less.
<5>
The content of the second carbon black is 10 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the rubber material, and the total of the first carbon black and the second carbon black is 80 parts by mass. The bioelectrode according to any one of <2> to <4>, which is 50 parts by mass or more and 70 parts by mass or less with respect to the
<6>
The content of the second carbon black is 15 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the rubber material, and the total of the first carbon black and the second carbon black is 80 parts by mass. The bioelectrode according to <5>, which is 55 parts by mass or more and 65 parts by mass or less with respect to
<7>
The bioelectrode according to any one of <1> to <6>, wherein the biocontact portion of the bioelectrode has a volume resistivity of 1×10 ⁵ Ω·cm or less.
<8>
The bioelectrode according to any one of <1> to <7>, wherein the biocontact portion of the bioelectrode has a rubber hardness of 30° or more and 60° or less.
<9>
The bioelectrode according to any one of <1> to <8>, wherein the rubber material is silicone rubber.
<10>
A biomedical signal measuring device comprising the biomedical electrode according to any one of <1> to <9> and measuring a biosignal.
<11>
The biological signal measuring device according to <10>, wherein the biological signal is an electroencephalogram.

According to the invention according to <1>, the accuracy is higher than that of a bioelectrode having a biocontact portion that contacts a biomaterial, has conductivity, and contains a rubber material and one type of carbon black. It is possible to provide a bioelectrode that measures biosignals well.
According to the invention pertaining to <2>, the living body contacting portion that contacts the living body contains two or more types of carbon black having a DBP oil absorption of less than 200 cm ³ /100 g, or the DBP oil absorption is 200 cm ³ /100 g or more. A bioelectrode that measures a biosignal with high accuracy can be provided as compared with the case where two or more types of carbon black are included.
According to the invention according to <3> or <4>, the difference in DBP oil absorption (absolute value) between the first carbon black and the second carbon black is less than 70 cm ³ /100 g. It is possible to provide a bioelectrode that measures biosignals well.
According to the invention according to <5> or <6>, the content of the second carbon black is less than 10 parts by mass or more than 30 parts by mass with respect to 100 parts by mass of the rubber material, or the first carbon black A bioelectrode that measures a biosignal with high accuracy can be provided compared to the case where the amount is less than 50 parts by mass or more than 70 parts by mass with respect to a total of 80 parts by mass of the second carbon black.

According to the invention according to <7>, it is possible to provide a biomedical electrode that measures a biomedical signal with higher accuracy than when the volume resistivity of the biomedical contact portion of the biomedical electrode exceeds 1×10 ⁵ Ω·cm.
According to the invention according to <8>, it is possible to provide a bioelectrode that measures a biosignal with higher accuracy than when the rubber hardness of the biocontact portion of the bioelectrode is less than 30° or more than 60°.
According to the invention according to <9>, it is possible to provide a bioelectrode that has high biosafety and accurately measures a biosignal compared to rubber materials such as isoprene and butyl rubber.

According to the invention pertaining to <10>, when the biomedical electrode has a biomedical contact portion that is in contact with a biomedical body and is conductive and contains a rubber material and one kind of carbon black, In comparison, a biosignal measuring device that measures biosignals with high accuracy can be provided.
According to the invention pertaining to <11>, when the biomedical electrode has a biomedical contact portion that is in contact with a biomedical body and is conductive and contains a rubber material and one type of carbon black, In comparison, a biomedical signal measuring device that measures an electroencephalogram as a biosignal with high accuracy can be provided.

1 is a schematic perspective view showing an example of a bioelectrode according to this embodiment; FIG. FIG. 4 is a schematic perspective view showing another example of the bioelectrode according to this embodiment; 1 is a block diagram showing an example of a biological signal measuring device according to an embodiment; FIG.

An embodiment that is an example of the present invention will be described below.

<Bioelectrode>
The bioelectrode according to the present embodiment has a biocontact portion that is in contact with a living body, has conductivity, and contains a rubber material and two or more kinds of carbon black with different DBP oil absorptions.
Here, in the biomedical electrode according to this embodiment, at least the biomedical contact portion that comes into contact with a living body has the above configuration, and the entire electrode may be a member having the above configuration.

The biomedical electrode according to this embodiment measures a biomedical signal with high accuracy due to the configuration described above. The reason is presumed as follows.

2. Description of the Related Art In order to measure biosignals such as electroencephalograms, heartbeats, and pulses, bioelectrodes are used to measure weak currents flowing from the skin surface of living organisms. In addition, in order to measure biosignals with high accuracy, at least the biomedical contact portion of the biomedical electrode is required to have low resistance and dynamic followability to the biomedical body (that is, adhesion to the biomedical body).

Here, in order to reduce the resistance of the biomedical contact portion of the biomedical electrode, it is effective to blend carbon black, which has a high DBP oil absorption, as a conductive agent.
However, since carbon black with a high DBP oil absorption also functions as a strong reinforcing agent, the rubber hardness of the living body contact portion increases. As a result, the adhesion of the living body contact portion to the living body, that is, the dynamic followability to the living body is also lowered, and the detection accuracy of the biosignal may be lowered.
On the other hand, when carbon black having a low DBP oil absorption is blended, the distance between the carbon blacks does not reach a distance that contributes to the resistance, so it is difficult to achieve low resistance. Therefore, the biosignal detection accuracy may decrease. Since carbon black with a low DBP oil absorption is a low reinforcing agent, there is little change in the rubber hardness of the living body contact portion.

Therefore, in the bioelectrode according to the present embodiment, at least the biocontact portion is configured to have conductivity and to contain two or more types of carbon black having different DBP oil absorption and a rubber material.
By mixing carbon blacks with different DBP oil absorptions, carbon blacks with a small DBP oil absorption are interposed between carbon blacks with a large DBP oil absorption, and low resistance is realized.
On the other hand, the effect of carbon having a high DBP oil absorption as a reinforcing agent is reduced, and rubber hardness is suppressed.
As a result, while ensuring the electrical conductivity of the living body contact portion, an excessive increase in comb hardness is suppressed, and adhesion to the living body (that is, dynamic followability to the living body) is enhanced.
In addition, carbon black with a high DBP oil absorption tends to have low dispersibility and large variation in resistance, but by blending carbon black with a low DBP oil absorption, the variation is reduced.

From the above, it is presumed that the biomedical electrode according to this embodiment accurately measures biomedical signals.

Details of the bioelectrode according to this embodiment will be described below.

The bioelectrode according to this embodiment is exemplified by, for example, a sheet-like bioelectrode as shown in FIG.
A sheet-like biomedical electrode is exemplified by, for example, a single-layer structure of a layered biomedical contact portion. On the other hand, the sheet-like bioelectrode may be a structure of two or more layers having a substrate and a layered biocontact portion provided on the substrate. In other words, the bioelectrode may be a structure composed entirely of the biocontact portion, or the bioelectrode may be composed of the biocontact portion and a member other than the biocontact portion (for example, a base material supporting the biocontact portion). It may be a structure having

The shape of the bioelectrode according to this embodiment is not particularly limited, and is selected according to the application. For example, the bioelectrode may be a structure (see FIG. 2) composed of a substrate and a plurality of protruding biocontact portions provided on the surface of the substrate.

1 and 2, reference numeral 10 denotes a bioelectrode, 12 a biocontact portion, and 14 a substrate.

Next, the configuration of the biocontact portion of the bioelectrode according to this embodiment will be described. In addition, it is only called a living body contact part, and it demonstrates.

The living body contact portion contains a rubber material and carbon black. The living body contact portion may contain other additives.

-Rubber material-
Rubber materials include epichlorohydrin rubber, urethane rubber, nitrile rubber, isoprene rubber, butadiene rubber, epichlorohydrin-ethylene oxide rubber, ethylene-propylene-diene rubber (EPDM), styrene-butadiene rubber (SBR), chlorinated polyisoprene, acrylonitrile-butadiene. Rubber (NBR), chloroprene rubber, hydrogenated polybutadiene, butyl rubber, silicone rubber, etc., or a mixture of two or more of these may be used. The rubber material also includes an elastomer.
Among these, urethane rubber, nitrile rubber, epichlorohydrin (ECO) rubber, ethylene-propylene-diene rubber (EPDM), and silicone are used as rubber materials from the viewpoint of improving adhesion to the living body and improving the measurement accuracy of biosignals. Rubber is preferable, and urethane rubber and silicone rubber are more preferable. In particular, silicone rubber is preferred because of its high biosafety.

-Carbon black-
Two or more carbon blacks with different DBP oil absorptions are used for the carbon black.
Of the two or more types of carbon blacks with different DBP oil absorptions, at least two types of carbon blacks have a DBP oil absorption of 70 cm ³ from the viewpoint of lower resistance, improved adhesion to the living body, and improved biosignal measurement accuracy. /100 g or more and 400 cm ³ /100 g or less (preferably 100 cm ³ /100 g or more and 300 cm ³ /100 g or less).

Specifically, two or more types of carbon black having different DBP oil absorptions are selected from the viewpoint of lower resistance, improved adhesion to the living body, and improved biosignal measurement accuracy, and the DBP oil absorption is less than 200 cm ³ /100 g. (preferably 50 cm ³ /100 g or more and less than 200 cm ³ /100 g) of the first carbon black and the DBP oil absorption of 200 cm ³ /100 g or more (preferably 200 cm ³ /100 g or more and less than 500 cm ³ /100 g) of the second carbon It is preferred to apply black and .

From the same viewpoint, the DBP oil absorption difference (absolute value) between the first carbon black and the second carbon black is preferably 70 cm ³ /100 g or more and 400 cm ³ /100 g or less, and 100 cm ³ /100 g or more and 350 cm 3/100 g or less is more preferable, 100 cm ³ /100 g or more and 300 cm ³ /100 g or less is more preferable, and 150 cm ³ /100 g or more and ^{300 cm 3 /} 100 g or less is particularly preferable.
When two or more of each of the first carbon black and the second carbon black are used in combination, the DBP oil absorption difference (absolute value) is the weighted average value of the content of each carbon black.

As the first carbon black, carbon black with a DBP oil absorption of 28 cm ³ /100 g (Asahi Thermal, manufactured by Asahi Carbon Co., Ltd.), carbon black with a DBP oil absorption of 63 cm ³ /100 g (Asahi #50U, Asahi Carbon Co., Ltd.) ), carbon black with a DBP oil absorption of 75 cm ³ /100 g (Asahi #70L, manufactured by Asahi Carbon Co., Ltd.), carbon black with a DBP oil absorption of 130 cm ³ /100 g (#3030B, manufactured by Mitsubishi Chemical Corporation), DBP oil absorption carbon black (#3050B, manufactured by Mitsubishi Chemical Corporation) in an amount of 175 cm ³ /100 g;
As the second carbon black, carbon black with a DBP oil absorption of 220 cm ³ /100 g (Asahi F-200SHS, manufactured by Asahi Carbon Co., Ltd.), and Ketjen black with a DBP oil absorption of 300 cm ³ /100 g (ECP200L, Lion Specialty Co., Ltd.). Chemicals Co., Ltd.), Ketjenblack with a DBP oil absorption of 365 cm ³ /100 g (EC300J, Lion Specialty Chemicals Co., Ltd.), Ketjenblack with a DBP oil absorption of 495 cm ³ /100 g (ECP600JD, Lion Specialty Chemicals) (manufactured by Chemicals Co., Ltd.) and the like.

Here, the DBP oil absorption indicates the amount of dibutyl phthalate (DBP) absorbed by 100 g of carbon black, and is a value defined in ASTM (American Standard Test Method) D2414-6TT.

The carbon black (e.g., the first and second carbon blacks) is oxidized carbon black having oxygen-containing functional groups (carboxyl group, quinone group, lactone group, hydroxyl group, etc.) formed on its surface by oxidation treatment. It's good. Oxidized carbon black can be produced by the air oxidation method in which carbon black contacts and reacts with air in a high-temperature atmosphere, the method in which it reacts with nitrogen oxides, ozone, etc. at normal temperature, and the method of air oxidation at high temperature followed by ozone oxidation at low temperature. It is obtained by the method of

The pH of the carbon black (for example, the first and second carbon blacks) is preferably 2 or more and 10 or less, more preferably 5 or more and 9 or less.
The pH of carbon black is the pH of an aqueous solution obtained by adding 50 g of carbon black to 1000 ml of water at 20° C., and is a value measured by the pH measurement method specified in JIS Z8802 (2011).
When two or more types of carbon black are used together, the pH of the carbon black is the weighted average value of the content.

From the viewpoint of dispersibility, the average primary particle size of carbon black (for example, the first and second carbon blacks) is preferably 10 nm or more and 100 nm or less, more preferably 20 nm or more and 50 nm or less.

The average primary particle size of carbon black is measured by the following method.
A measurement sample with a thickness of 200 nm is obtained by cutting the living body contact portion to be measured with a microtome, and this measurement sample is observed with a TEM (transmission electron microscope). Then, the diameters (maximum diameters) of 50 primary particles of carbon black are measured, and the average value is defined as the average primary particle diameter.

The content of the entire carbon black (for example, the total of the first and second carbon blacks) is 100 parts by mass of the rubber material from the viewpoint of reducing the resistance and improving the adhesion to the living body, as well as improving the measurement accuracy of the biosignal. , preferably 40 to 80 parts by mass, more preferably 50 to 70 parts by mass.

In particular, from the same viewpoint, the content of the second carbon black among the carbon blacks is preferably 10 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the rubber material, and more preferably 15 parts by mass or more and 25 parts by mass or less. preferable.
In addition, the content of the second carbon black is preferably 50 parts by mass or more and 70 parts by mass or less with respect to a total of 80 parts by mass of the first carbon black and the second carbon black, and 55 parts by mass or more and 65 parts by mass. It is more preferably not more than parts by mass,

However, from the viewpoint of lowering the resistance and improving the adhesion to the living body, as well as improving the measurement accuracy of the biosignal, the content of the second carbon black is , 10% by mass to 80% by mass, 10% by mass to 75% by mass, 10% by mass to 70% by mass, and 10% by mass to 50% by mass.

In addition to reducing the resistance of the bioelectrode portion and improving the adhesion to the living body, if it is possible to improve the measurement accuracy of the biosignal, electronic conductive conductive agents other than carbon black, ion conductive conductive agents, conductive polymers, etc. of conductive material.

－Other Additives－
Other additives include, for example, foaming agents, flame retardants, deterioration inhibitors, foam stabilizers, and various fillers.
Examples of foaming agents include benzenesulfonyl hydrazide, azodicarbonamide, N,N'-dinitrosopentamethylenetetramine and mixtures thereof.
Examples of flame retardants include phosphoric acid ester compounds such as trischloroethyl phosphate and trischloropropyl phosphate.
Anti-degradation agents include, for example, antioxidants such as phenol antioxidants, amine antioxidants, and phosphite antioxidants; UV absorbers such as benzotriazole UV absorbers and benzophenone UV absorbers; Hindered amine-based light stabilizers and the like are included.
Examples of foam stabilizers include silicone-based surfactants such as dimethylsilicone oil and polyether-modified silicone oil, cationic surfactants, anionic surfactants, and amphoteric surfactants.
Examples of various fillers include silica and calcium carbonate.
In addition to the above, other additives such as softeners, plasticizers, hardeners, antioxidants, surfactants, coupling agents, fillers (silica, calcium carbonate, etc.) can be added to comb materials. materials that can be used.

Other additives include the following additives.
Vulcanizing agents for rubber materials include, for example, vulcanizing agents that abstract sulfur or halogen groups such as 2,4,6-trimercapto-s-triazine and 6-methylquinoxaline-2,3-dithiocarbamate for vulcanization. is mentioned.
Vulcanization accelerators for rubber materials include thiazole, sulfenamide, thiuram, dicarbamate, and xanthate. These may be used alone or in combination of two or more. In addition, known rubber compounding materials such as zinc oxide and stearic acid can be added.

Platinum catalysts for crosslinking silicone rubber include chloroplatinic acid, alcohol solution of chloroplatinic acid, reaction product of chloroplatinic acid and alcohol, reaction product of chloroplatinic acid and olefin compound, chloroplatinic acid and vinyl group reaction products with containing siloxane; platinum-based catalysts such as platinum-olefin complexes and platinum-vinyl group-containing siloxane complexes; and platinum group metal-based catalysts such as rhodium complexes and ruthenium complexes. Moreover, those obtained by dissolving or dispersing these catalysts in an alcohol-based, hydrocarbon-based or siloxane-based solvent may also be used.

Moreover, when an addition-curable silicone resin is used, an addition reaction inhibitor may be added. This addition reaction control agent is added as a quencher to prevent the action of the platinum catalyst in the solution and under a low temperature environment before heat curing after coating film formation. Specifically, 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclohexanol, 3 -methyl-3-trimethylsiloxy-1-butyne, 3-methyl-3-trimethylsiloxy-1-pentyne, 3,5-dimethyl-3-trimethylsiloxy-1-hexyne, 1-ethynyl-1-trimethylsiloxycyclohexane, Bis(2,2-dimethyl-3-butynoxy)dimethylsilane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,1,3,3-tetramethyl -1,3-divinyldisiloxane and the like.

As a method for photocuring, use a resin with a (meth)acrylate or olefin end, or add a cross-linking agent with a (meth)acrylate, olefin, or thiol group at the end, and Examples include a method of adding a photo-radical generator that generates radicals, and a method of adding a photo-acid generator that generates an acid by light using a resin or a cross-linking agent having an oxirane group, an oxetane group, or a vinyl ether group. be done.

Photoradical generators include acetophenone, 4,4′-dimethoxybenzyl, benzyl, benzoin, benzophenone, 2-benzoylbenzoic acid, 4,4′-bis(dimethylamino)benzophenone, 4,4′-bis(diethylamino). Benzophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, benzoin isobutyl ether, 4-benzoylbenzoic acid, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetra Phenyl-1,2'-biimidazole, methyl 2-benzoylbenzoate, 2-(1,3-benzodioxol-5-yl)-4,6-bis(trichloromethyl)-1,3,5- Triazine, 2-benzyl-2-(dimethylamino)-4'-morpholinobtyrophenone, 4,4'-dichlorobenzophenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,4- Diethylthioxanthen-9-one, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), 1,4-dibenzoylbenzene, 2-ethylanthraquinone, 1-hydroxycyclohexylphenylketone, 2-hydroxy-2 -methylpropiophenone, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 2-isonitrosopropiophenone, 2-phenyl-2-(p-toluenesulfonyloxy)acetophenone can be mentioned.

It can also be cured by adding a thermally decomposable radical generator. Thermal radical generators include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile). , 4,4′-azobis(4-cyanovalenic acid), 2,2′-azobis(methylpropionamidine)hydrochloride, 2,2′-azobis[2-(2-imidazolin-2-yl)propane]hydrochloride, 2 , 2′-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis(cyclohexane-1-carbonitrile), 1[(1-cyano-1-methylethyl)azo]formamide, 2,2′-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 2,2′-azobis[N-(2-propenyl)-2-methylpropionamide], 2,2′- Azobis (N-butyl-2-methylpropionamide), dimethyl-2,2'-azobis (isobutyrate), 4,4'-azobis (4-cyanopentanoic acid), dimethyl-2,2'-azobis (2- methyl propionate), benzoyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, di-tert-butyl peroxide, di-tert-amyl peroxide, di-n-butyl peroxide, dimethyl-2, 2′-azobis(2-methylpropronate), dicumyl peroxide and the like can be mentioned.

Examples of photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethanes, N-sulfonyloxyimides, oxime-O-sulfonate acid generators, and the like.

-Characteristics of the part that comes into contact with the living body-
The volume resistivity of the living body contact portion is preferably 1×10 ⁵ Ω·cm or less, more preferably 1×10 ³ Ω·cm or less, from the viewpoint of lowering resistance and improving biosignal measurement accuracy.
The volume resistivity of the living body contact portion is a value measured by the following method.
A sheet-shaped measurement sample is collected from the living body contact portion, and the measurement sample is measured according to JIS K 6911 (1995), using a measuring jig (R12702A / B resistivity chamber: manufactured by Advantest) and a high resistance measuring device (R8340A). Using a digital high-resistance/micro-ammeter: Advantest Co., Ltd.), after applying a voltage adjusted so that the electric field (applied voltage/composition sheet thickness) is 1000 V / cm for 30 seconds, from the current value flowing, the following Calculate using the formula.
Volume resistivity (Ωcm) = (19.63 × applied voltage (V)) / (current value (A) × measurement sample thickness (cm))

The rubber hardness of the living body contact portion is preferably 20° or more and 80° or less, more preferably 30° or more and 60° or less, and 35° or more and 55° from the viewpoint of improving the adhesion to the living body and improving the measurement accuracy of the biosignal. ° or less is more preferable.
The rubber hardness of the living body contact portion is Shore A hardness. Shore A hardness complies with JIS K 6253-3 (2012). Specifically, with a durometer type A, the numerical value 15 seconds after indentation of the sample is measured as rubber hardness (that is, Shore A hardness).

The surface roughness Rz of the living body contact surface of the living body contact portion is preferably 5 μm or more and 50 μm or less, more preferably 10 μm or more and 40 μm or less, from the viewpoint of improving adhesion to the living body and improving biosignal measurement accuracy.
The surface roughness Rz of the surface of the charging member is the ten-point average roughness Rz of JIS B 0601-1994.
The surface roughness Rz was measured using a surface roughness measuring machine (Surfcom 1400A manufactured by Tokyo Seimitsu Co., Ltd.) under the conditions of a cutoff of 0.8 mm, a measurement length of 4.0 mm, and a traverse speed of 0.3 mm/sec. Measure the points and calculate the average value.

The living body contact portion may be made of foam or may be made of non-foam.

-Method for manufacturing a living body contact part-
There is no particular limitation on the method of manufacturing the living body contact portion.
The living body contact portion is manufactured by extruding a mixture containing, for example, a rubber material (eg, unvulcanized rubber material), carbon black, and other additives using an extruder or the like.
In addition, the living body contact portion may be molded into a desired shape by using a mold or the like on a preformed sheet-like material, or may be formed by blasting such as shot blasting, sand blasting, liquid blasting, or the like. It may be molded into a shape of

-Applications of bioelectrodes-
A bioelectrode is applied as an electrode of a biometric device that measures biosignals such as electroencephalograms, heartbeats, and pulses, for example.
Specifically, the bioelectrode is, for example, 1) a bioelectrode for electroencephalogram measurement inserted into the ear canal of the ear of a living body (for example, a human body), 2) a bioelectrode for electroencephalogram measurement, which is provided on the ear hook portion. 3) a bioelectrode for electroencephalogram measurement placed on the forehead or the entire head of a living body (e.g. human body); 4) a living body (e.g. human body) placed on arms, legs, chest or abdomen It is applied to pulse measurement electrodes (or heartbeat measurement electrodes) and the like.

(Biological signal measuring device)
A biomedical signal measuring device according to this embodiment is a device that measures a biomedical signal, and includes the biomedical electrode according to this embodiment.

For example, as shown in FIG. 3, a biomedical signal measuring apparatus 101 according to the present embodiment includes a biomedical electrode 10, a holding member 20 that holds the biomedical electrode 10, and a biomedical signal obtained by the biomedical electrode 10 (for example, signals such as electroencephalograms, pulse, and heartbeat); a display unit 24 for displaying various information including information on the biosignal; , a communication interface 28 for transmitting processed signals to an external device, and a control section 30 for controlling each section of the device 101 .

The holding member 20 is, for example, for electroencephalogram measurement inserted into the external auditory canal of the ear of a living body (for example, human body), for electroencephalogram measurement provided in an ear hook portion, or placed on the forehead or the entire head of the living body (for example, human body). It is a member having a shape according to the application, such as for measuring an electroencephalogram, or for measuring a pulse (or for measuring a heartbeat) placed on an arm, leg, chest, or abdomen of a living body (for example, a human body).

The biological signal processing unit 22 is composed of various processing circuits such as a signal amplifier circuit, for example.
The display unit 24 is configured by, for example, a liquid crystal display. The display unit 24 may employ a touch panel system and function as the input unit 26 .
The input unit 26 includes various input devices such as a pointing device (mouse, etc.), keyboard, and buttons.
The communication interface 28 is an interface for communicating with an external device (personal computer for biosignal measurement, mobile terminal), and uses standards such as Ethernet (registered trademark), FDDI, Wi-Fi (registered trademark), for example. be done.

Although not shown, the control unit 30 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a storage, and an input/output interface (I/O). are connected so that they can communicate with each other.

The CPU is a central processing unit that executes various programs and controls each section. That is, the CPU reads a program from ROM or storage and executes the program using RAM as a work area. The CPU performs control of each of the above components and various arithmetic processing according to programs recorded in the ROM or storage.
The ROM stores various programs and various data. RAM temporarily stores programs or data as a work area.
The storage is composed of a HDD (Hard Disk Drive), SSD (Solid State Drive) or flash memory, and stores various programs including an operating system and various data.

The configuration of the biosignal measuring apparatus according to the present embodiment is not limited, and a configuration corresponding to the biosignal to be measured is adopted. Further, the biomedical signal measuring device may be a terminal device that does not display information about the measured biomedical signal and only transmits the measured biomedical signal to an external device.

For example, the biological signal measurement device according to the present embodiment is
1) An electroencephalogram measuring device provided with a measuring unit having a bioelectrode, which is inserted into the ear canal of the ear of a living body (for example, a human body) 2) An electroencephalogram measuring device provided with an ear-hook-shaped measuring unit having a bioelectrode 3) A living body (for example, a human body) 4) An electroencephalogram measurement device equipped with a measurement unit having bioelectrodes, which is installed on the forehead or the entire head of the human body) 4) A bioelectrode installed on the arms, legs, chest, or abdomen of a living body (e.g. pulse measuring device (or heart rate measuring device)
etc. are exemplified.

The biomedical signal measuring apparatus according to the present embodiment has a biomedical electrode that has a low resistance, a high adhesiveness (specifically, dynamic followability) of the biomedical electrode to the living body, and a biomedical signal that can be accurately measured. , suitable for an electroencephalogram measurement device that measures electroencephalograms as biological signals.

EXAMPLES Hereinafter, the present embodiment will be described more specifically with reference to examples and comparative examples, but the present embodiment is not limited to the following examples.

<Example 1>
99.825 mol % of dimethyl siloxane units and 0.15 mol % of methylvinyl siloxane units 100 parts of a rubbery organopolysiloxane having an average degree of polymerization of about 5,000 and 0.025 mol % of dimethylvinyl siloxane units is added with DBP oil absorption of 360 cm ³ / 100 g Ketjenblack EC300J (manufactured by Lion Specialty Chemicals Co., Ltd.): 20 parts, DBP oil absorption of 130 cm ³ /100 g carbon black 3030B (manufactured by Mitsubishi Chemical Corporation): 40 parts, and 2 parts of fumed silica and 1.0 part of a coupling agent were mixed with a pressure kneader to prepare a base compound.
Next, a compound obtained by adding 1.5 parts of C-8A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a curing agent to the base compound is molded in a mold with a thickness of 2 mm at 165 ° C. for 15 minutes, and then at 200 ° C. for 4 hours. processed to obtain a rubber sheet.
This rubber sheet was cut into a bioelectrode having a size of 50 mm×50 mm.

<Examples 2 to 10, Comparative Examples 1 to 2>
A rubber sheet was obtained in the same manner as in Example 1, except that the type and amount (number of parts) of carbon black were changed according to Table 1. The obtained rubber sheet was used as a bioelectrode.

<Evaluation>
(various characteristic values)
The following properties of the obtained bioelectrode were measured according to the methods described above.
・Volume resistivity (logΩcm)
・Rubber hardness (Shore A hardness) (°)
・Surface roughness of living body contact surface (μm)

(Bioelectrode evaluation)
Using the obtained bioelectrode, bioelectrode evaluation was performed as follows. As for the frequency, since alpha brain waves have a specific peak at 8 Hz to 14 Hz, evaluation was performed by transmitting an alternating voltage signal of 10 Hz to the bioelectrode and evaluating the difference between input and output. An input (reference) AC voltage signal was measured without passing through the bioelectrode.
Without connecting the bioelectrode (rubber sheet), Mind Wave Mobile manufactured by Neurosky Co., Ltd. and a function generator (33120A 15 MHz function/arbitrary waveform generator manufactured by Hewlett-Packard) are connected. As for the connection method, the function generator and the input side to the NeuroSky Mind Wave Mobile are connected with an alligator clip so that the bioelectrode can be connected, and the REF and GND from the NeuroSky Mind Wave Mobile are connected. are connected to the function generator with the alligator clip terminal as the output side. An AC voltage signal of 10 μV and 10 Hz is transmitted from the function generator, the waveform of the reference is measured, and the waveform data is output to the PC. Next, the bioelectrode is connected between the output of the function generator and a Mind Wave Mobile manufactured by Neurosky Co., Ltd. An AC voltage signal of 10 μV and 10 Hz is transmitted from the function generator to measure the waveform of the bioelectrode (rubber sheet). At this time, the interval between the alligator clips connected to the bioelectrode (rubber sheet) is set to 10 mm. The ratio of the difference between the average value of 50 cycles of the peak-to-peak value of one cycle of the voltage waveform when the bioelectrode (rubber sheet) is connected and the average value of 50 cycles of the peak-to-peak value of one cycle of the reference voltage waveform. Differences between the presence and absence were evaluated.

Then, the difference between the presence and absence of the bioelectrode was evaluated according to the following criteria.
A (◎): The ratio of the difference in the average value from the reference is within ± 0.5% B (○): The ratio of the difference in the average value from the reference is within ± 1.0% C (△): The ratio with the reference The ratio of the difference in the average value is within ±1.5% D (×): The ratio of the difference in the average value from the reference is outside ±1.5%

From the above results, it can be seen that the biomedical electrode of the present example can measure an electroencephalogram as a biomedical signal with higher accuracy than the biomedical electrode of the comparative example.

Details of the carbon black used in each example are as follows.
Asahi Thermal: carbon black, manufactured by Asahi Carbon Co., Ltd., DBP oil absorption 28 cm ³ /100 g, average primary particle size = 80 nm
Asahi #50U: carbon black, manufactured by Asahi Carbon Co., Ltd., DBP oil absorption 63 cm ³ /100 g, average primary particle size = 70 nm
· #3030B: carbon black, manufactured by Mitsubishi Chemical Corporation, average primary particle size = 55 nm
- FX35: carbon black, manufactured by Denka Co., Ltd., DBP oil absorption 220 cm ³ /100 g, average primary particle size = 26 nm
ECP200L: Ketjenblack, manufactured by Lion Specialty Chemicals Co., Ltd., DBP oil absorption 300 cm ³ /100 g, average primary particle size = 35 nm
・EC300J: Ketjenblack, manufactured by Lion Specialty Chemicals Co., Ltd., DBP oil absorption 360 cm ³ /100 g, average primary particle size = 39.5 nm
Lionite CB: carbon black, manufactured by Lion Specialty Chemicals Co., Ltd., DBP oil absorption 378 cm ³ /100 g, average primary particle size = 28 nm
HS500: carbon black, manufactured by Asahi Carbon Co., Ltd., DBP oil absorption 500 cm ³ /100 g, average primary particle size = 38 nm

10 Biomedical electrode 20 Holding member 22 Biomedical signal processing unit 24 Display unit 26 Input unit 28 Communication interface 30 Control unit 101 Biosignal measuring device

Claims (11)

1. A bioelectrode having a biocontact portion that is in contact with a living body and that is conductive and contains a rubber material and two or more kinds of carbon black having different DBP oil absorptions. The living body contact portion contains, as the two or more types of carbon black, a first carbon black having a DBP oil absorption of less than 200 cm ³ /100 g and a second carbon black having a DBP oil absorption of 200 cm ³ /100 g or more. The bioelectrode according to claim 1, comprising: The bioelectrode according to claim 2, wherein the DBP oil absorption difference (absolute value) between the first carbon black and the second carbon black is 70 cm ³ /100 g or more and 400 cm ³ /100 g or less. The bioelectrode according to claim 3, wherein the DBP oil absorption difference (absolute value) between the first carbon black and the second carbon black is 100 cm ³ /100 g or more and 300 cm ³ /100 g or less. The content of the second carbon black is 10 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the rubber material, and the total of the first carbon black and the second carbon black is 80 parts by mass. The bioelectrode according to any one of claims 2 to 4, which is 50 parts by mass or more and 70 parts by mass or less with respect to the The content of the second carbon black is 15 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the rubber material, and the total of the first carbon black and the second carbon black is 80 parts by mass. 6. The bioelectrode according to claim 5, wherein the content is 55 parts by mass or more and 65 parts by mass or less. The bioelectrode according to any one of claims 1 to 6, wherein the volume resistivity of the biocontact portion of the bioelectrode is 1×10 ⁵ Ω·cm or less. The bioelectrode according to any one of claims 1 to 7, wherein the biocontact portion of the bioelectrode has a rubber hardness of 30° or more and 60° or less. The bioelectrode according to any one of claims 1 to 8, wherein the rubber material is silicone rubber. A biomedical signal measuring device comprising the biomedical electrode according to any one of claims 1 to 9 and measuring a biomedical signal. 11. The biological signal measuring device according to claim 10, wherein the biological signal is an electroencephalogram.

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