JP2020180405A - Conductive fiber structure and electrode member - Google Patents

Abstract

To provide a conductive fiber structure achieving high conductivity and low impedance and an electrode member capable of preventing corrosion of a metal member in contact without causing rashes in a living body.SOLUTION: There is provided a conductive fiber structure formed by adhering a conductor composed of a conductive substance and a binder to a substrate fiber, in which the conductive substance is carbon black and the conductor is carried on the surface of a single fiber constituting the substrate fiber and in a gap between single fibers, and in a gap between single yarns, and the mass concentration of a sulfur element in a surface layer of the conductive fiber structure is 1 mass% or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a conductive fiber structure and an electrode member.

The bioelectrodes used to measure bioelectric signals such as brain waves, electrocardiograms, and electromyograms of humans and animals, and to apply electrical stimulation to living organisms are gel electrodes, rubber electrodes, electrodes using thin metal plates, and conductivity. Various types of bioelectrodes are used, such as those using sex fiber materials.

The gel electrodes and rubber electrodes have the advantages of being highly flexible, adhering to the body surface of the living body, and enabling stable biological signal acquisition, but have poor air permeability, causing stuffiness at the contact points, rashes, etc. There was a problem of causing.

Further, the electrode using the thin metal plate has a problem that it is hydrophobic and hard, and has low compatibility with applications where it comes into contact with the body surface of a living body which is rich in water and flexible. High contact pressure was required or a conductive paste (jelly) had to be used to bring it into close contact with the body surface.

As an electrode that can be directly attached to the body surface of a living body without using a conductive paste or the like, a textile-shaped electrode having conductivity is considered to be effective, and various proposals have been made. The textile electrode is resistant to bending and can change its shape according to the unevenness of the body surface. In the textile-shaped electrode, in order to impart conductivity, a fiber plated with metal or a fiber coated with a conductive polymer has been proposed. While these techniques are widely used, metal-plated fibers can cause allergic reactions and require high contact pressure to adhere to the body surface.

Regarding textile electrodes coated with a conductive polymer, for example, thiophene-based PEDOT-PSS ((3,4-ethylenedioxythiophene) -poly (styrene sulfonic acid)) is used as a material having good compatibility with living organisms. The electrodes used have been proposed. It has excellent conductivity and hydrophilicity, and while it is highly suitable for applications that come into contact with the body surface of living organisms, it may cause corrosion of other metal electrode members to be joined, and it is stable for storage as an electrode. There is a problem with sex.

As a conductive substance for textile electrodes, those using carbon have been proposed. Carbon is less likely to cause allergic reactions and metal corrosion and is inexpensive. As a textile electrode using carbon, an electrode using a conductive material having carbon black powder added to silicon rubber and having impermeable to moisture has been proposed (see Patent Document 1).

As a textile using carbon, a fiber structure in which carbon is kneaded into fibers has been proposed. It is composed of a resin composition containing carbon black in aromatic polyester, has shapeability, suppleness and strength peculiar to synthetic fibers, high wear resistance, has constant conductivity regardless of temperature and humidity changes, and has a surface surface. It is said to provide a conductive fiber structure in which the conductive agent is less likely to fall off from the surface (see Patent Document 2).

Further, as a textile using carbon, an electrode in which a metal or carbon-coated fiber base material is coated with a conductor containing a conductive polymer has been proposed. Further, a composite material in which PEDOT-PSS, which is a conductive polymer, is fixed inside and outside a fiber or a fiber bundle (thread) has been proposed (Patent Documents 3, 4, and 5).

Japanese Patent No. 4860155 Japanese Unexamined Patent Publication No. 2010-100971 JP-A-2015-140493 International Publication No. 2015/115441 International Publication No. 2013/073763

However, the electrode portion of the fabric electrode disclosed in Patent Document 1 is a silicon rubber to which carbon black or silver powder which is a conductive substance is added, but since the silicon rubber is bonded to the fabric by an adhesive or a hot press, When the conductor does not support the fiber gap and is used as a bioelectrode, the continuity of the conductor is lost when the conductive fiber structure is bent to follow the body surface, and a weak signal is transmitted. Difficult to get or enter.

The technique described in Patent Document 2 has a limit in conductive performance because when a conductive fiber is used as a cloth, conduction can be obtained only at the contact point between the fibers. In addition, since carbon is squeezed into the insulating polymer, a portion having no conductivity is generated on the fiber surface, and the impedance becomes high in the application of transmitting an electric signal or an electric stimulus. Further, the movement of the fabric may cause the fibers to float or separate at the contact points between the fibers, which may disturb the conduction, which makes it difficult to use as a bioelectrode.

Further, the techniques of Patent Documents 3, 4 and 5 have a problem of causing corrosion of other metal electrode members in contact with the textile electrode, similar to the textile electrode coated with the conductive polymer described above.

In view of the above, it is an object of the present invention to provide a conductive fiber structure that realizes high conductivity and low impedance, and an electrode member that is less likely to cause a rash on a living body and can prevent corrosion of a metal member in contact with the body. And.

In order to solve the above problems and achieve the object, the conductive fiber structure of the present invention is a conductive fiber structure in which a conductor made of a conductive substance and a binder is attached to a base fiber. The conductive substance is carbon black, and the conductor is a conductive fiber structure supported on the surface of the single fiber constituting the base fiber and in the gap between the single fiber and the single fiber, and the conductive material. The surface layer of the fiber structure is characterized in that the mass concentration of sulfur elements is 1% by mass or less.

Further, the conductive fiber structure of the present invention is preferably used as an electrode member constituting a bioelectrode.

Further, the electrode member for the bioelectrode of the present invention is characterized by using the above-mentioned conductive fiber structure.

According to the present invention, a conductive fiber structure that realizes high conductivity and low impedance, and an electrode member that does not cause a rash on a living body and can prevent corrosion of a metal member in contact with the living body can be obtained.

It is a conceptual diagram of the cross section of one aspect of the conductive fiber structure of this invention. It is an optical microscope observation photograph of one aspect of the conductive fiber structure of this invention. It is an optical microscope observation photograph of one aspect of the conductive fiber structure of this invention.

Hereinafter, embodiments of the conductive fiber structure according to the present invention will be described in detail. The present invention is not limited to this embodiment.

<< Conductive fiber structure >>
The conductive fiber structure of the present invention is a conductive fiber structure in which a conductor made of a conductive substance and a binder is attached to a base fiber, the conductive substance is carbon black, and the conductor is A conductive fiber structure supported on the surface of the single fiber constituting the base fiber and in the gap between the single fiber and the single fiber, and the mass concentration of sulfur element in the surface layer of the conductive fiber structure is It is in a specific range.

The surface layer of the conductive fiber structure referred to here refers to the surface of the conductive fiber structure observed by SEM-EDX (energy dispersive X-ray fluorescence) described later, and is substantially conductive fiber. It is a part involved in the conductivity of the structure.

That is, in the present invention, a conductor is supported on the surface of a single fiber and in the gap between the single fiber and the single fiber, and by connecting the surface and the gap with a conductor having a specific composition, the coating thread of the conductor or the conductor can be formed. Compared with the case where the kneaded yarn is used as a cloth, an excellent conductive fiber structure can be obtained by having a large number of conductive paths and suppressing corrosion of contacting metal members.

FIG. 1 is a conceptual view of a cross section of one aspect of the conductive fiber structure of the present invention. In the cross section of the conductive fiber structure 1, the conductor 3 is present on the surface of the single fiber 2 or in the gap between the single fibers. , Many conductive paths are continued. 2 and 3 are optical microscope observation photographs of the conductive fiber structure used in the examples. The white part shows the fiber, and the black part shows the conductor containing carbon black. FIG. 2 shows the conductive fiber structure used in Example 4, which is composed of a highly shrinkable yarn having a diameter of 23 μm and nanofibers having a diameter of 700 nm. FIG. 3 shows the conductive fiber structure used in Example 6, which is composed of only threads having a normal diameter of 15 μm. In both cases of FIGS. 2 and 3, it can be confirmed that the single fiber gap is filled with the conductor.

The conductor is a compound for imparting conductivity to a conductive fiber structure, and is composed of (A) a conductive substance and (B) a binder. The conductor may contain other components in addition to (A) the conductive substance and (B) the binder. Examples of other components include (C) conductivity improver, (D) flexibility imparting agent, (E) surfactant and / or leveling agent, cross-linking agent, catalyst, defoaming agent and the like. It is not limited.

<(A) Conductive substance>
The conductive substance used in the present invention is carbon black (hereinafter referred to as CB). The CB content in the CB-containing conductor is preferably 5% by mass to 80% by mass, more preferably 20% by mass to 50% by mass. When it is 5% by mass or more, the conductive performance in the conductive fiber structure becomes apparent due to the continuity of carbon black, and when it is 20% by mass or more, the conductive performance is further improved. Further, by setting the CB content to 80% by mass or less, the robustness in friction of the conductive fiber structure can be obtained.

In addition, when imparting conductivity by CB, the particle diameter forming the base of CB (the particle diameter of the particles constituting the structure, hereinafter the particles may be referred to as primary particles, and the particle diameter may be referred to as primary particle diameter). It is important to consider the structure, which is a chain structure, and the surface properties of the particles. When preparing a solution containing CB and a binder, it is particularly important that the specific surface area of the particle surface texture is large. A large specific surface area means that there are many pores on the surface of the particles, and the binder enters the pores, the distance between the particles can be reduced, which leads to high conductivity. The specific surface area can be measured by the BET method, BET specific surface area preferably has 400~2000m ² / g, it is more preferred 600~1600m ² / g. When it is 400 m ² / g or more, the distance between particles becomes sufficiently small, and it becomes a range where sufficient conductivity can be imparted to the fiber structure, and even higher conductivity performance can be obtained at 600 m ² / g or more. By setting the upper limit to 2000 m ² / g or less, the structure can be maintained, and stable conductive performance can be imparted to the fiber structure.

Further, in order to obtain high conductivity, it is desirable that the primary particles of CB are small, the average particle diameter of the primary particles of CB is preferably in the range of 1 to 200 nm, and more preferably in the range of 5 to 100 nm. When it is 1 nm or more, the toughness in friction of the conductive fiber structure becomes apparent, and when it is 5 nm or more, high toughness can be obtained. When it is 200 nm or less, the conductive performance is sufficiently imparted to the fiber structure, and when it is 100 nm or less, high conductivity is imparted.

In order to obtain a high conductivity, it is desirable to structure is highly developed, dibutyl phthalate (DBP) absorption thereof is preferably 100~600cm ³ / 100g, an indicator of structure size, it is more preferable of 300~500cm ³ / 100g. With 100 cm ^3/100 g or more, the conductive performance is manifested by structure ^development, further conductive performance is improved by 300 cm 3/100 g or more. The toughness of the conductive fiber structure in friction becomes apparent, and high toughness can be obtained at 5 nm or more. 600 cm ^3/100 g is suppressed high viscosity by less, in the interior of the fibers can be sufficiently permeated, can impart sufficient conductivity performance fiber structure.

<(B) Binder>
The conductor further contains (B) a binder in addition to the above (A) conductive substance. The role of the binder (B) used here is to support the compound constituting the conductor on the surface of the monofibers constituting the fiber base material and in the gap between the monofibers. In the present invention, the single fiber refers to one fiber such as one filament constituting the multifilament and one short fiber constituting the spun yarn, and the yarn refers to the multifilament, spun yarn, twisted yarn and the like. Refers to a single thread composed of an aggregate of single fibers.

Preferred specific examples of the binder include olefin resin, polyester resin, urethane resin, epoxy resin, silicone resin, vinyl chloride resin, nylon resin, acrylic resin and the like, and at least one selected from this group. It is preferable that the number is one. As the binder (B), the (B1) urethane resin or (B1) urethane resin or (B1) from the viewpoint of preventing the compound constituting the conductor in the conductive fiber structure from falling off from the base fiber and more reliably imparting conductivity. B2) Acrylic resin is preferable.

<(B1) Urethane resin>
It is preferable to use the urethane resin (B1) as a binder because it has an extremely high effect of supporting the compound constituting the conductor in the conductive fiber structure on the fiber base material and preventing it from falling off. (B1) Urethane resin is classified into ether-based, ester-based, carbonate-based, modified polyol, ester / carbonate-based, or a polymer in which they are combined, depending on the polyol of the raw material, and any of them can be used. From the viewpoint of hydrolysis resistance, ether-based urethane resin and carbonate-based urethane resin are particularly preferable.

(B1) Commercially available products that can be used as urethane resins include "Resamine D (registered trademark)" (manufactured by Dainichi Seika Co., Ltd.) as an ether or carbonate-based urethane resin, and Superflex as an ether-based, carbonate or ester-based urethane resin (B1). (Manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Coronate (manufactured by Toso Co., Ltd.) and the like as ether-based or ester-based urethane resins.

<(B2) Acrylic resin>
(B2) It is preferable to use an acrylic resin as a binder because it has a high effect of supporting the compound constituting the conductor in the conductive fiber structure on the fiber base material and preventing it from falling off. As the (B2) acrylic resin, either an acrylic resin or a methacrylic resin obtained by using an acrylic acid ester and / or a methacrylic acid ester as a raw material monomer can be used. Acrylic resins can have various properties depending on the type of acrylic acid ester or methacrylic acid ester as the raw material, and any of them can be used in the present invention. The resin is not particularly limited, but is composed of 50 to 99% by mass of acrylic acid ester and / or methacrylic acid ester units, and 1 to 50% by mass of other monomer units copolymerizable therewith. Those are preferable because they can impart properties such as flexibility and water resistance.

(B2) Examples of commercially available products that can be used as acrylic resins include Boncoat AN (manufactured by DIC Corporation), Polysol AT (manufactured by Showa Denko Corporation), Casesol ARS (manufactured by NICCA CHEMICAL CO., LTD.), And the like.

In the conductive fiber structure of the present invention, as the binder (B), the glass transition temperature (Tg) of the binder is preferably −60 to ± 0 ° C. from the viewpoint of the flexibility of the obtained conductive fiber structure. .. Further, from the viewpoint of the abrasion resistance of the obtained conductive fiber structure, the tensile strength of the binder alone is preferably 5 to 50 MPa. When it is 5 MPa or more, the toughness due to friction of the conductive fiber structure can be obtained, and when it is 50 MPa or less, the flexibility peculiar to the textile of the conductive fiber structure can be maintained.

In the above, the tensile strength is a value measured based on the method for measuring the tensile strength of the binder, which will be described later.

The binder (B) includes a solvent system and an aqueous system, and it is preferable to use an aqueous system from the viewpoint of reducing VOC during production. The binder may be used alone or in combination of two or more.

In the conductive fiber structure of the present invention, the content of the binder (B) is not particularly limited, but is preferably 10 to 1000 parts by mass, preferably 100 to 500 parts by mass, based on 100 parts by mass of the solid content of the (A) conductive substance. Parts by mass are more preferred. When the amount is 10 parts by mass or more, the (A) conductive substance of the obtained conductive fiber structure is hard to fall off, and when the amount is 1000 parts by mass or less, the (A) conductive substance in the conductive fiber structure is hard to fall off. It is preferable because the content of the substance is not excessively reduced and sufficient conductivity can be ensured when used as an electrode member.

In the conductive fiber structure of the present invention, the conductor may contain other components in addition to (A) the conductive substance and (B) the binder. Examples of other components include (C) conductivity improver, (D) flexibility imparting agent, (E) surfactant and / or leveling agent, cross-linking agent, catalyst, defoaming agent and the like.

<(C) Conductivity improver>
(C) Conductivity improver may be added to the conductor. The (C) conductivity improver is not particularly limited, but for example, a compound having a boiling point of 100 ° C. or higher and having two or more hydroxyl groups in the molecule, and a sulfinyl group having a boiling point of 100 ° C. or higher and having at least one sulfinyl group in the molecule. Examples thereof include a compound having a boiling point of 60 ° C. or higher and having at least one carbonyl group in the molecule, and a compound having a boiling point of 100 ° C. or higher and having at least one amide group in the molecule. These (C) conductivity improvers may be used alone or in combination of two or more.

Examples of the compound having a boiling point of 100 ° C. or higher and having two or more hydroxyl groups in the molecule include ethylene glycol, diethylene glycol, propylene glycol, trimethylene glycol, β-thiodiglycol, triethylene glycol, tripropylene glycol, 1 , 4-Butanediol, 1,5-Pentanediol, 1,3-Butanediol, 1,6-Hexenediol, Neopentyl glycol, Catecol, Cyclohexanediol, Cyclohexanedimethanol, Glycerin, Elytritor, Inmator, Lactitol, Martinol , Mannitol, sorbitol, xylitol, sucrose and the like. These may be used alone or in combination of two or more.

Examples of the compound having a boiling point of 100 ° C. or higher and having at least one sulfinyl group in the molecule include dimethyl sulfoxide and the like.

Examples of compounds having a boiling point of 60 ° C. or higher and having at least one carbonyl group in the molecule include acrylic acid, methacrylic acid, methanic acid, ethaneic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, octanoic acid, and decane. Acids, dodecanoic acid, benzoic acid, p-toluic acid, p-chlorobenzoic acid, p-nitrobenzoic acid, 1-naphthoic acid, 2-naphthoic acid, phthalic acid, isophthalic acid, oxalic acid, malonic acid, succinic acid, Examples thereof include adipic acid, malonic acid, and phthalic acid. These may be used alone or in combination of two or more.

Examples of compounds having a boiling point of 100 ° C. or higher and having at least one amide group in the molecule include N, N-dimethylacetamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-ethylacetamide, and N-. Examples thereof include phenyl-N-propylacetamide and benzamide. These may be used alone or in combination of two or more.

When the conductor contains (C) a conductivity improver, the content thereof is not particularly limited, but (A) 0.01 to 100,000 parts by mass is preferable with respect to 100 parts by mass of the conductive substance, and 0.1 to 0. 10000 parts by mass is more preferable. (C) When the content of the conductivity improving agent is 0.01 parts by mass or more, a sufficient conductivity improving effect can be obtained, and when it is 100,000 parts by mass or less, the drying property of the conductive fiber structure is improved. It is good.

<(D) Flexibility imparting agent>
The (D) flexibility-imparting agent may be added to the conductor. The flexibility-imparting agent (D) is not particularly limited, and examples thereof include glycerol, sorbitol, polyglycerin, polyethylene glycol, polyethylene glycol-polypropylene glycol copolymer, and the like. These may be used alone or in combination of two or more.

When the conductor contains (D) a flexibility-imparting agent, the content thereof is not particularly limited, but (A) 10 to 10000 parts by mass is preferable with respect to 100 parts by mass of the conductive substance, and 100 to 5000 parts by mass is preferable. More preferred. (D) When the content of the flexibility-imparting agent is 10 parts by mass or more, sufficient flexibility is obtained, and when it is 10,000 parts by mass or less, the fiber structure is excellent in conductivity and strength, and the washing resistance is significantly lowered. There is no such thing.

<(E) Surfactant and / or leveling agent>
In the present invention, a surfactant added to uniformly disperse the compound constituting the conductor in the conductor and a leveling agent added for the purpose of equalizing the surface tension of the conductive fiber structure during drying are used. It may be added to the conductor. In the conductive fiber structure of the present invention, one compound may correspond to both a surfactant and a leveling agent. Further, when the surfactant and the leveling agent are different compounds, the surfactant and the leveling agent may be used in combination.

As the surfactant, those having dispersion of solid components in a solvent are preferable, and specific examples thereof include polyether-modified polydimethylsiloxane, polyether-modified siloxane, polyether ester-modified hydroxyl group-containing polydimethylsiloxane, and poly. Siloxane-based compounds such as ether-modified acrylic group-containing polydimethylsiloxane, polyester-modified acrylic group-containing polydimethylsiloxane, perfluoropolydimethylsiloxane, perfluoropolyether-modified polydimethylsiloxane, and perfluoropolyester-modified polydimethylsiloxane; perfluoroalkylcarboxylic Fluorine-containing organic compounds such as acids and perfluoroalkyl polyoxyethylene ethanol; polyether compounds such as polyoxyethylene alkyl phenyl ethers, propylene oxide polymers and ethylene oxide polymers; carboxylic acids such as coconut oil fatty acid amine salts and gum rosins; Ester compounds such as castor oil sulfates, phosphate esters, alkyl ether sulfates, sorbitan fatty acid esters, sulfonic acid esters, and succinic acid esters; sulfonate compounds such as alkylaryl sulfonic acid amine salts and dioctyl sodium sulfosuccinate; Phosphate compounds such as sodium lauryl phosphate; amide compounds such as coconut oil fatty acid ethanolamide; acrylic compounds and the like can be mentioned. These surfactants may be used alone or in combination of two or more. Among these, a siloxane compound and a fluorine-containing organic compound are preferable because the effect of improving the leveling property can be remarkably obtained.

The leveling agent is not particularly limited, and is, for example, polyether-modified polydimethylsiloxane, polyether-modified siloxane, polyether ester-modified hydroxyl group-containing polydimethylsiloxane, polyether-modified acrylic group-containing polydimethylsiloxane, and polyester-modified acrylic group-containing poly. Siloxane-based compounds such as dimethylsiloxane, perfluoropolydimethylsiloxane, perfluoropolyether-modified polydimethylsiloxane, and perfluoropolyester-modified polydimethylsiloxane; fluorine-containing organic compounds such as perfluoroalkylcarboxylic acid and perfluoroalkylpolyoxyethyleneethanol. Polyether-based compounds such as polyoxyethylene alkylphenyl ether, propylene oxide polymer, ethylene oxide polymer; carboxylic acids such as coconut oil fatty acid amine salt and gum rosin; castor oil sulfates, phosphoric acid esters, alkyl ether sulfates, Ester compounds such as sorbitan fatty acid ester, sulfonic acid ester, and succinic acid ester; sulfonate compounds such as alkylaryl sulfonic acid amine salt and dioctyl sodium sulfosuccinate; phosphate compounds such as sodium lauryl phosphate; palm oil fatty acid ethanol An amide compound such as amide; an acrylic compound and the like can be mentioned. These leveling agents may be used alone or in combination of two or more.

<Manufacturing method of conductive fiber structure>
In the conductive fiber structure of the present invention, a conductor containing (A) a mixture of a conductive substance and (B) a binder as a main component is used as a surface of a single fiber constituting a base fiber and a single fiber and a single fiber. It is obtained by supporting it in the gap. When supporting the conductor, it is preferable to support it in the form of a dispersion or solution of the conductor. In the present specification, a material that completely dissolves all the components contained in the conductor (that is, a "solvent") and a material that disperses an insoluble component (that is, a "dispersion medium") are particularly distinguished. Instead, they are all described as "solvents". The solvent will be described below.

<Solvent>
The solvent is not particularly limited, and is, for example, water; alcohols such as methanol, ethanol, 2-propanol, 1-propanol and glycerin; ethylene glycols such as ethylene glycol, diethylene glycol, triethylene glycol and tetraethylene glycol; Glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mononormal butyl ether, diethylene glycol monomethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether; ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether Glycol ethers such as acetate Acetates; propylene glycols such as propylene glycol, dipropylene glycol, tripropylene glycol; propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, propylene glycol Propylene glycol ethers such as dimethyl ether, dipropylene glycol dimethyl ether, propylene glycol diethyl ether and dipropylene glycol diethyl ether; propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether Examples thereof include propylene glycol ether acetates such as acetate; tetrahydrofuran; acetone; acetonitrile and the like. These solvents may be used alone or in combination of two or more.

The solvent is preferably water or a mixture of water and an organic solvent. When the conductive fiber structure contains water as a solvent, the content of water is not particularly limited, but (A) 20 to 10000 parts by mass is preferable with respect to 100 parts by mass of the solid content of the conductive substance, and 200 parts by mass. ~ 500,000 parts by mass is more preferable. When the water content is 20 parts by mass or more, the viscosity does not become too high and the handling is good. When the water content is 1,000,000 parts by mass or less, the concentration of the conductive fiber structure does not become too low and the liquid is used. The amount does not increase too much.

In the present invention, the conductor is supported on the base fiber by a usual method such as a dipping method, a coating method, or a spray method, and the fiber structure supporting the conductor is heated to obtain a conductive fiber structure. be able to.

The dipping method or the coating method is preferable because a large amount of the conductor can be supported on the surface of the single fiber constituting the fiber structure and in the gap between the single fiber and the single fiber.

It is desirable that the conductive substance (A) is mixed with the surfactant (E) in advance and uniformly dispersed in the solvent, and the dispersibility is maintained even when the binder (B) is mixed. desirable. In the process of uniformly dispersing a conductive substance in a solvent, for example, a ball mill, a bead mill, a planetary ball mill, a vibrating ball mill, a sand mill, a colloid mill, an attritor, a roll mill, a high-speed impeller dispersion, a disperser, a homogenizer, a high-speed impact mill, and an ultra Examples thereof include, but are not limited to, a mechanical stirring method using a sonic dispersion, a stirring blade, a stirrer, or the like.

From the viewpoint of improving and stabilizing the conductivity of the conductive fiber structure, a fiber structure containing a conductor to which glycerol, physiological saline or the like is further added can be preferably used, but the conductivity of the present invention can be used. The fiber structure is not limited to these. By applying these illustrated conductors to the base fibers using known methods such as a dipping method, a coating method, and a spray method, the conductors are conductive on the surface of the single fibers constituting the base fibers and in the gaps between the single fibers. The body can be supported to form a continuous layer of conductors.

<Base fiber>
In the conductive fiber structure of the present invention, the cross-sectional shape of the fibers constituting the base fiber may be a round cross section, a triangular cross section, a flat cross section, a polygonal cross section, a hollow type, or any other deformed cross section having a high degree of deformation. It is not limited.

The base fiber used in the present invention may be a natural fiber or a semi-synthetic fiber, but a synthetic fiber is preferable from the viewpoint of processability. The polymer which is the material of the fiber constituting the base fiber is not particularly limited as long as it is a polymer that can be fiberized by a known method, and a polymer for polyolefin fibers containing polyethylene, polypropylene, etc. as a main component, rayon, acetate, etc. Fiber elements for chemical fibers and polymers for thermoplastic synthetic fibers such as polyester and nylon can be used, but are not limited thereto.

The form of the base fiber according to the present invention includes mesh, papermaking, woven fabric, knitted fabric, non-woven fabric, ribbon, string and the like, but is not particularly limited as long as it is in a form suitable for the purpose of use.

The form of the fiber may be any of monofilament yarn, multifilament yarn, and staple yarn, but from the viewpoint of supporting the conductor on the base fiber and high conductivity of the conductive fiber structure, there are a plurality of base fibers. It preferably contains a multifilament yarn composed of single fibers.

The single fiber fineness is not particularly limited, and examples thereof include about 0.0001 dtex to 300 dtex.

Further, in the base fiber according to the present invention, it is preferable that all or a part of the single fiber contains so-called microfiber having a fiber diameter of 5 μm or less. Further, it is more preferable to contain so-called nanofibers of less than 1 μm. Since microfibers and nanofibers are densely assembled with single fibers and the single fiber gaps are fine, even a small amount of conductor can be filled, which is suitable for improving the conductivity of a conductive fiber structure. is there.

In addition to fiber entanglement and raising, the base fiber has shrinkage treatment, shape fixing treatment, compression treatment, dyeing finish treatment, oil addition treatment, heat fixing treatment, solvent removal, shape fixing agent removal, combing treatment, and polishing treatment. , Flat (roll) breath treatment and high-performance shortcut shirring treatment (cutting of fluff) are carried out in appropriate combinations at each place of each process, but as long as the performance as an electrode is not impaired, it is carried out. It is not limited.

Further, the basis weight of the conductive fiber structure of the present invention is preferably 5 g / m ² or more and 500 g / m ² or less. When the basis weight is 5 g / m ² or more, the fabric is not too thin, the fiber structure has sufficient strength, and when the basis weight is 500 g / m ² or less, it has good flexibility. More preferably, it is 10 g / m ² or more and 250 g / m ² or less.

<Characteristics of fiber structure>
The conductive fiber structure of the present invention has the above-mentioned preferable embodiment, and when the supporting state of the conductor is confirmed by observing a thin section of the conductive fiber structure with an optical microscope, the conductor holds the base fiber. It is confirmed that it is supported on the surface of the constituent single fibers and in the gap between the single fibers and the single fibers. If the conductor is not supported on the surface of the single fiber constituting the base fiber and in the gap between the single fiber and the single fiber, when the conductor is used as a bioelectrode, the conductive fiber structure is provided so as to follow the body surface. At the time of bending, the continuity of the conductor is lost, and it becomes difficult to acquire or input a weak signal. However, in the conductive fiber structure of the present invention, the conductor constitutes the base fiber. It is supported on the surface of the fiber and in the gap between the single fiber and the single fiber, and when the conductive fiber structure is bent to follow the body surface, a weak signal is not lost without losing the continuity of the conductor. Can be obtained or entered.

The conductive fiber structure of the present invention has a volume resistivity of 1 × 10 ⁶ Ω · cm when the volume resistivity is measured by the five-point measurement method shown in JIS K 7194 (1994) by adopting the above preferred embodiment. The following is preferable. When used as a bioelectrode, it is difficult to acquire or input a weak signal if the resistance value is high, but the conductive fiber structure of the present invention has a low resistance value and acquires or inputs a weak signal. It is possible. More preferably, the volume resistivity is 1 × 10 ³ Ω · cm or less.

The conductive fiber structure of the present invention achieves an impedance of 2 kΩ or less between two conductive fiber structures when a load is 500 g according to ANSI standard 4.2.2.1 by using a preferred embodiment. It is also possible. When used as a bioelectrode, if the impedance between conductive fiber structures is high, it becomes difficult to acquire or input a weak signal, but in the present invention, the impedance between conductive fiber structures is low and a weak signal. It is possible to obtain or input a conductive fiber structure.

Further, the conductive fiber structure of the present invention determines the water absorption time when a water absorption test is performed to measure the time until the test piece absorbs the water droplet when 0.005 mL of ion-exchanged water is dropped by the injection needle. It is also possible to set it to 1800 seconds or less. When the fiber structure is used as a bioelectrode, if there is no water absorption, stuffiness and rash may occur due to sweat on the skin surface. However, the conductive fiber structure of the present invention has water absorption and thus causes skin surface. It can absorb sweat and suppress the occurrence of stuffiness and rash.

Further, when the conductive fiber structure of the present invention is subjected to elemental analysis by SEM-EDX (energy dispersive X-ray fluorescence) and the sulfur element content (mass concentration) of the surface layer of the conductive fiber structure is measured. , The content thereof is 1% by mass or less. If it exceeds 1% by mass, it causes corrosion of the metal member and the metal wiring that come into contact with the conductive fiber structure, and the metal cannot be conductive if left for a long period of time.

Since it is necessary to control the sulfur element content of the surface layer of the conductive fiber structure from the viewpoint of the corrosion, here, in order to evaluate the sulfur element content of the surface layer of the conductive fiber structure, the above Make measurements by method.

Further, in order to suppress metal corrosiveness, it is preferably 0.5% by mass or less. If it contains a sulfur component, it induces metal corrosion due to thermal decomposition, ultraviolet rays, oxygen in the air, deterioration over time, etc. Corrosive sulfur gas such as hydrogen sulfide, sulfur dioxide, and carbonyl sulfide, and acidic substances such as sulfonic acid. May cause total corrosion that sulfides the metal surface, or local corrosion that localizes the position of the anode and causes intensive corrosion.

In addition, local corrosion includes dissimilar metal contact corrosion in which dissimilar metals come into contact to form a galvanic cell and the one with a lower potential corrodes, and the content of metal elements in the conductive fiber structure should be 1% by mass or less. Is desirable. In particular, precious metals such as gold, silver, platinum, palladium, rhodium, iridium, ruthenium, and osmium have a low ionization tendency. Therefore, when a base metal member is joined, the member is easily corroded and the content is preferably low. .. Further, the base metals such as iron, copper and nickel are easily corroded by themselves and preferably have a low content.

Further, in the conductive fiber structure of the present invention, when the conductive fiber structure is brought into contact with a metal and an accelerated deterioration test is performed, the rate of change of the resistance value before and after the accelerated deterioration is preferably 20% or less. The large rate of change is considered to indicate that the metal has been corroded by the conductive fiber structure. Conductive fiber structures containing some conductive polymer compounds have a high rate of change, and it is necessary to take measures to prevent corrosion of metal members. In the present invention, it is possible to provide a conductive fiber structure having good compatibility with a metal member. The accelerated deterioration test is carried out by the method described later.

The shape and size of the electrode member of the present invention are not particularly specified as long as the biological signal can be detected and input.

Further, in the electrode member using the conductive fiber structure of the present invention, a resin layer may be laminated on the surface opposite to the biological contact surface of the conductive fiber structure, and fibers, films and the like are laminated. You may. Resins, fibers, and films can be laminated for the purposes of electrical stimulation insulation, moisture permeability, and moisturization, but are not limited to this.

A preferred mode of use of the conductive fiber structure of the present invention includes a form in which it can directly contact with a living body to acquire an electric signal and / or apply an electric signal or an electric stimulus. Examples thereof include electrode members such as electrocardiographic potential, myoelectric potential, and electroencephalogram that acquire electrical signals from a living body, and electrode members such as low frequency, high frequency, and EMS that impart electrical stimulation to a living body.

Specific shapes include electrodes, electric wires, clothing, pants, gloves, socks, brassieres, headbands, wristbands, neckbands, hats, bellybands, supporters, shoes, sheets, and glasses made of the conductive fiber structure. Items that come into direct contact with the skin, such as headbands, hair ornaments, headphones, watches, chairs, toilet seats, handles, beds, carpets, and various covers, are preferable, but are not limited to these. Then, by attaching a sensor, an electric stimulator, or the like so as to be conductive with a part of these products, for example, a conductive fiber structure, various products having the function of an electrode member can be obtained.

In the case of electrodes, the form of the electrodes alone and / or in combination with those that come into direct contact with the skin can also be preferably used. The shape of the electrode alone is not limited to a circular diameter, a polygon, or the like.

The size of the electrode may be a contact area for obtaining a desired biological signal, and is not limited. In order to improve the adhesion to the living body, a general flat electrode may have a three-dimensional structure such as a loop shape so as to be easily linked with the movement, or may be inflated with air.

When used in combination with other structures such as clothes as electrodes, conductive fiber structures can be used in combination with buttons, hooks, magnets, and velcro (registered trademark) to make clothes so that electrical signals of desired parts can be obtained. It can also be suitably used as a removable shape.

Next, the conductive fiber structure of the present invention will be described in detail by way of examples. The conductive fiber structure of the present invention is not limited to these examples. The measured values in the examples and comparative examples were obtained by the following methods.

<Single fiber fineness of base fiber>
The fineness of the single fiber constituting the base fiber of the present invention was obtained by extracting a yarn from the base fiber which was a sample before the raw yarn or the conductor-imparting treatment, and in the case of a mixed fiber, divided by fineness. The mass (g) of 1 m was measured for each of the divided yarns, and the yarn fineness was calculated by multiplying by 10,000. This was repeated 10 times, and the value obtained by rounding the second decimal place of the simple average value divided by the number of single fibers constituting the yarn was defined as the single fiber fineness (dtex).

<Fiber diameter of base fiber>
The yarn extracted from the base fiber which is the sample before the conductor imparting treatment of the present invention is embedded in epoxy resin, frozen by a cryosectioning system (FC / 4E type manufactured by Reichert), and equipped with an ultra equipped with a diamond knife. It was cut with a microtome (Reichert-Nissei ultracut N). Then, the cut surface was photographed with a scanning electron microscope (SEM) (VE-7800 type manufactured by KEYENCE CORPORATION) at 5000 times for nanofibers, 1000 times for microfibers, and 500 times for others. Ten randomly selected single fibers were extracted from the obtained photographs, the areas of all single fiber cross sections were measured for the photographs using image processing software (WINROOF), and the fiber cross sections were tentatively made into perfect circles from the areas. The fiber diameter was calculated, and the average of 10 fibers was taken as the fiber diameter (nm).

<Metsuke of base fiber>
Regarding the base fiber which is the sample before the conductor imparting treatment of the present invention, the marking per unit area in the standard state of JIS L1096 (general woven fabric test method) (1999) and JIS L1018 (knit fabric test method) (1999) is performed. It was measured.

<Glass transition point (Tg) of binder>
The binder before blending with the conductor was measured using a differential scanning calorimetry device (DSC-7) manufactured by PerkinElmer Co., Ltd. at a heating rate of 16 ° C./min with 10 mg of data. The definition of Tg is that after observing the heat absorption peak temperature (Tm1) that is observed when the temperature rise rate is 16 ° C./min, the temperature is maintained at about (Tm1 + 20) ° C. for 5 minutes, and then rapidly cooled to room temperature (Tm1). The heat absorption peak temperature observed as a stepped baseline deviation was defined as Tg when the measurement was performed again under the heating condition of 16 ° C./min after the quenching time and the room temperature holding time were held for 5 minutes in total).

<Tensile strength of binder (MPa)>
For the binder before blending with the conductor, apply the binder solution on the Corona discharge-treated PET film, and treat it as pre-drying at room temperature for 15 hours, main drying at 80 ° C. for 6 hours, and dry heat treatment at 120 ° C. for 20 minutes. A film having a thickness of 0.5 mm was formed and peeled from the corona discharge-treated PET film to obtain a test piece. A 30 mm x 10 mm test piece was prepared, and the tensile strength was measured with a tensile strength tester (autograph manufactured by Shimadzu Corporation). The test atmosphere was 23 ° C., 50% RH, the distance between chucks was 10 mm, and the test speed was 100 mm / min.

<Specific surface area of CB>
The CB before being blended into the conductor was measured using an automatic specific surface area / pore size distribution measuring device (BELSORP-mini2 manufactured by Microtrac Bell) according to JIS K 6217-2 (2001 version).

<DBP oil absorption of CB>
The CB before being blended into the conductor was measured using an absorber meter (absorbometer C type manufactured by Brabender) in accordance with JIS K 6217-4 (2001 version).

<Primary particle size of CB>
A block in which CB before being blended with a conductor is embedded in an epoxy resin is cut with an ultramicrotome to prepare a thin section having a thickness of 60 nm to 100 nm, and a transmission electron microscope (TEM) observation device (Hitachi Seisakusho) The H-7100FA type) was observed at an acceleration of 75 kV at an arbitrary magnification that can clearly measure the primary particle size of CB out of a magnification of 20,000 to 100,000 times, and the obtained photograph was digitized in black and white. .. The primary particle size of the photograph was confirmed by image analysis of the CB that appeared in black with WinROOF (version 2.3) manufactured by Mitani Corporation of computer software. The areas of all the CBs existing on the photograph were calculated, and the diameters of the CBs calculated by determining that they were substantially circular from the area values were calculated, and the average was taken as the average particle diameter.

<Amount of CB adhered to conductive fiber structure>
The amount of the conductor adhered was measured by changing the mass of the fiber structure, which is a test cloth, before and after applying the dispersion liquid of the conductor in the standard state (20 ° C. × 65% RH). The calculation formula is as follows.
Amount of conductor adhered (g / m ² ) = (mass of test cloth after processing (g) -mass of test material before processing (g)) / area of test cloth coated with dispersion (m ² )

Further, the CB adhesion amount was calculated by multiplying the CB solid content ratio in the conductor. The calculation formula is as follows.
CB adhesion amount (g / m ² ) = conductor adhesion amount (g / m ² ) x CB solid content ratio (%)

<Volume resistivity of conductive fiber structure>
The measurement was performed by the 5-point measurement method shown in JIS K 7194 (1994). The resistance value (Ω) was measured at 20 ° C. and 40% RH environment using a resistance meter (Mitsubishi Analytech Four-probe Resistance Meter Loresta-AX MCP-T370). Further, the dough thickness was measured by a JIS L 1096 (2010) 8.4A method with a thickness measuring device (medium-sized thickening meter UF-60A manufactured by Daiei Kagaku Seiki Seisakusho) having a presser foot with a diameter of 2 cm. The volume resistivity (Ω · cm) was calculated from the obtained measured values and the correction coefficient.

<Impedance between electrodes of conductive fiber structure>
The conductive fiber structure was used as a 4 cm × 4 cm test piece, the load was 500 g, and the impedance between electrodes (kΩ) was measured according to ANSI standard 4.2.2.1.

<Water absorption of conductive fiber structure>
As a water absorption test, when 0.005 mL of ion-exchanged water is dropped with an injection needle, the time until the test piece absorbs the water droplet is measured. Specifically, in the standard state (20 ° C. × 65% RH), the test piece of the conductive fiber structure is spread horizontally so as not to wrinkle and sag, and 0.005 mL of distilled water is sprinkled on the test piece using an injection needle. The time from when the water droplets reach the surface of the test piece to when the specular reflection disappears as the test piece absorbs the water droplets and only the wetness remains is measured in units of 10 seconds with a stopwatch. The average value of the test pieces is rounded off to the tens digit. However, if there is one or more test pieces that are not absorbed even after 1800 seconds or more, it is added as 1800 seconds or more.

<Sulfur element content in the surface layer of the conductive fiber structure>
The conductive fiber structure was observed with a scanning electron microscope (SEM), and the sulfur element content of the surface layer of the conductive fiber structure was determined by elemental analysis by SEM-EDX (energy dispersive X-ray fluorescence). Specifically, the surface layer of the conductive fiber structure is horizontally fixed to the sample table so as to be the observation surface, and the magnification is adjusted to 100 times by SEM (S-3400N manufactured by Hitachi High Technologies). Start SEM-EDX (EX-250 x-act manufactured by Horiba Seisakusho) with an acceleration voltage of 15 KV and a sample-detector distance (WD) of 10 mm, and point & ID function of the SEM-EDX control program (EMAX ENERGY manufactured by Horiba Seisakusho). Quantitative analysis of the elements in the surface layer of the conductive fiber structure was performed by selecting the entire observation field in, and the mass concentration of sulfur (mass%) when the mass concentration of all the detected elements was 100%. Asked. The elements detected by the quantitative analysis are the elements having a mass concentration (%) of 3 times or more the standard deviation among the elements detected by the qualitative analysis, and the detection limit concentration of the above device is the mass concentration of all the elements. When it is 100%, it is about 0.1%.

<Supported state of conductor>
A block in which a conductive fiber structure is embedded in an acrylic resin is cut with a microtome to prepare a thin section having a thickness of 1 μm to 10 μm, the thin section is placed on a slide glass, and the conductive fiber is measured by an optical microscope. The carrying state of the conductor is permeated and observed at an arbitrary magnification (for example, about 2000 times when the fiber diameter of the single fiber is 0.7 μm) at which the single fiber forming the structure can be discriminated, and the conductor is the base material. It was confirmed whether the fibers were supported on the surface of the single fibers constituting the fibers or in the gaps between the single fibers and the single fibers. Specifically, when the conductor of the conductive fiber structure containing CB that does not transmit light is laminated on the surface layer of the base fiber, it is considered to be surface-supported. Further, when the conductor of the conductive fiber structure containing the CB that does not transmit light is filled in the gap between the single fiber of the base fiber that transmits light leaving a contour, it is said that the gap is supported. To do.

<Metal corrosiveness of conductive fiber structures>
The conductive fiber structure is cut into a 40 mm square, 5R square test piece, and a gold-plated dot button (manufactured by YKK Co., Ltd.) for clothing is placed in the center of the test piece, and clothing is placed at the four corners (center of the 5R corner). Copper-tin-plated or gold-plated dot buttons (manufactured by YKK Co., Ltd.) are attached by a caulking machine so that the caulking height is 1.8 mm, and wiring is connected to one of the central dot button and the four corner dot buttons. After connecting, connect a resistance value measuring device (manufactured by Sanwa Co., Ltd.) to the wiring, and accelerate deterioration for 48 hours under the conditions of temperature 70 ° C and humidity 30% RH with a constant temperature and humidity chamber, before and after acceleration deterioration. The resistance value (Ω) was measured, and the rate of change (%) of the resistance value was calculated by the following formula.
Rate of change (%) = [(Resistance after deterioration (Ω) -Resistance before deterioration (Ω)) / Resistance before deterioration (Ω)] x 100

Hereinafter, examples and comparative examples of the conductive fiber structure according to the present invention will be described.

[Example 1]
75dtex-112F of alkaline hot water soluble polyester composed of a copolymer of terephthalic acid and 5-sodium sulfoisophthalic acid as an acid component of polyester with an island component of polyethylene terephthalate (sea island ratio 30%: 70%, island) A circular knitted fabric was knitted with a smooth structure using a polyester mixed fiber obtained by mixing a sea-island type composite fiber of number 127 islands / F) and a high-shrink yarn of 33 dtex-6F. Next, the obtained knitted fabric was immersed in a 3% by mass aqueous solution of sodium hydroxide (75 ° C., bath ratio 1:30) to remove easily soluble components, and a knitted fabric using a mixed yarn of nanofibers and high shrinkage yarn was obtained. Obtained. The obtained knitted fabric as a base fiber was used as (A) carbon black shown below as "" Lion Paste (registered trademark) "W-376R" (Ketchen Black dispersion, manufactured by Lion Specialty Chemicals Co., Ltd.) 400 g / L. And (B) as a binder, "Superflex (registered trademark)" 460S "(Daiichi Kogyo Seiyaku Co., Ltd., non-yellowing isocyanate carbonate-based aqueous urethane resin) 526 g / L is immersed in a mixed solution at 150 ° C. It was heated to obtain a conductive fiber structure. Copper-tin-plated dot buttons were used to evaluate the metal corrosiveness of conductive fiber structures. The properties of the materials used and the obtained conductive fiber structure are shown in Table 1, and the results of elemental analysis are shown in Table 2. The obtained conductive fiber structure showed excellent volume resistivity and impedance between electrodes. Further, since it has water absorption, it can be used as an electrode member for a bioelectrode that is less likely to cause stuffiness or a rash. Sulfur and the metal elements (specifically, gold, silver, platinum, palladium, rhodium, iridium, ruthenium, osmium, iron, copper, nickel (hereinafter referred to as the metal elements)) are below the detection limit and are metal corrosive. Since the value was sufficiently low, it is possible to use a metal bonding member, and it is possible to provide an electrode member for a bioelectrode which is excellent in long-term storage.

[Example 2]
In the evaluation of the metal corrosiveness of the conductive fiber structure, the conductive fiber structure was manufactured by performing the same treatment as in Example 1 except that the gold-plated dot button was used. The properties of the materials used and the obtained conductive fiber structure are shown in Table 1, and the results of elemental analysis are shown in Table 2. Since the obtained conductive fiber structure had a metal corrosiveness even lower than that of Example 1, a metal bonding member could be used, and an electrode member for a bioelectrode excellent in long-term storage could be provided. ..

[Example 3]
(A) Other than changing carbon black from "Lion Paste (registered trademark)" W-376R to "Lion Paste (registered trademark)" W-356A (Ketchen Black dispersion, manufactured by Lion Specialty Chemicals) To produce a conductive fiber structure by performing the same treatment as in Example 1. Copper-tin-plated dot buttons were used to evaluate the metal corrosiveness of conductive fiber structures. The properties of the materials used and the obtained conductive fiber structure are shown in Table 1, and the results of elemental analysis are shown in Table 2. The obtained conductive fiber structure showed excellent volume resistivity and impedance between electrodes. Further, since it has water absorption, it can be used as an electrode member for a bioelectrode that is less likely to cause stuffiness or a rash. Since the sulfur element was 1% or less, other metals, specifically the metal element was below the detection limit, and the metal corrosiveness was sufficiently low, the metal bonding member could be used for a long period of time. It is possible to provide an electrode member for a bioelectrode which is excellent in storage.

[Example 4]
(B) Binder from "" Superflex (registered trademark) "460S" 526g / L to "" Superflex (registered trademark) "E-4800" (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., non-yellowing type isocyanate ether-based water-based urethane resin ) The same treatment as in Example 1 was performed except that the value was changed to 500 g / L to produce a conductive fiber structure. Copper-tin-plated dot buttons were used to evaluate the metal corrosiveness of conductive fiber structures. The properties of the materials used and the obtained conductive fiber structure are shown in Table 1, and the results of elemental analysis are shown in Table 2. The obtained conductive fiber structure showed excellent volume resistivity and impedance between electrodes. Further, since it has water absorption, it can be used as an electrode member for a bioelectrode that is less likely to cause stuffiness or a rash. Since sulfur and the metal element were below the detection limit and the metal corrosiveness was sufficiently low, the metal bonding member can be used, and an electrode member for a bioelectrode excellent in long-term storage can be provided.

[Example 5]
A conductive fiber structure was produced by performing the same treatment as in Example 4 except that the base fiber was changed to a knit using a mixed fiber of microfiber and high shrinkage yarn, which will be described later. A knit using a mixed yarn of microfiber and high shrinkage yarn was prepared as follows. 66dtex-9F (sea-island ratio 20%: 80%, island) of alkaline hot water-soluble polyester composed of a copolymer of terephthalic acid and 5-sodium sulfoisophthalic acid as an acid component of polyester with an island component of polyethylene terephthalate and a sea component of polyester. A circular knitted fabric was knitted with a smooth structure using a polyester mixed fiber yarn in which a sea island type composite fiber of several 70 islands / F) and a high shrinkage yarn of 33dtex-6F were mixed. Next, the obtained knitted fabric was immersed in a 3% by mass aqueous solution of sodium hydroxide (75 ° C., bath ratio 1:30) to remove easily soluble components, and a knitted fabric using a mixed yarn of microfiber and high shrinkage yarn was obtained. Obtained.

Copper-tin-plated dot buttons were used to evaluate the metal corrosiveness of conductive fiber structures. The properties of the materials used and the obtained conductive fiber structure are shown in Table 1, and the results of elemental analysis are shown in Table 2. The obtained conductive fiber structure showed excellent volume resistivity and impedance between electrodes. Further, since it has water absorption, it can be used as an electrode member for a bioelectrode that is less likely to cause stuffiness or a rash. Since sulfur and the metal element were below the detection limit and the metal corrosiveness was sufficiently low, the metal bonding member can be used, and an electrode member for a bioelectrode excellent in long-term storage can be provided.

[Example 6]
A conductive fiber structure was produced by performing the same treatment as in Example 4 except that the base fiber was changed to a knitted fabric consisting only of 84 dtex-72F polyester filament.

Copper-tin-plated dot buttons were used to evaluate the metal corrosiveness of conductive fiber structures. The properties of the materials used and the obtained conductive fiber structure are shown in Table 1, and the results of elemental analysis are shown in Table 2. The obtained conductive fiber structure showed excellent volume resistivity and impedance between electrodes. Further, since it has water absorption, it can be used as an electrode member for a bioelectrode that is less likely to cause stuffiness or a rash. Since sulfur and the metal element were below the detection limit and the metal corrosiveness was sufficiently low, the metal bonding member can be used, and an electrode member for a bioelectrode excellent in long-term storage can be provided.

[Comparative Example 1]
A solution prepared by mixing 400 g / L of "Lion Paste (registered trademark)" W-376R and 417 g / L of silicone-based binder "DOWNSIL (registered trademark)" IE-7170 (manufactured by Toray Dow Corning) is subjected to corona discharge treatment PET. It is applied on a film and treated for 15 hours at room temperature for pre-drying, 6 hours at 80 ° C. for main drying, and 20 minutes at 120 ° C. for dry heat treatment to form a film having a thickness of 0.5 mm, and the corona discharge treatment is performed. The CB silicone thin film obtained by peeling from the PET film was laminated on the knitted fabric as the base fiber obtained by performing the same treatment halfway as in Example 1, and heat-compressed at 150 ° C. for 15 seconds with a heating press machine. To obtain a conductive fiber structure. Copper-tin-plated dot buttons were used to evaluate the metal corrosiveness of conductive fiber structures. The properties of the materials used and the obtained conductive fiber structure are shown in Table 1, and the results of elemental analysis are shown in Table 2. Since the obtained conductive fiber structure does not support the gaps of the conductor except for the outermost layer, when it is used as a bioelectrode, when the conductive fiber structure is bent to be along the body surface or the like. The continuity of the conductor is lost, making it difficult to obtain or input a weak signal. In addition, since it does not absorb water, it may cause stuffiness or a rash when used as an electrode member for a bioelectrode.

[Comparative Example 2]
A 20% poly (p-polystyrene sulfonic acid) solution (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was applied to the conductive fiber structure obtained by performing the same treatment as in Example 1 at 94 g / m ² and at 130 ° C. Dry heat treatment was performed for 5 minutes to obtain a conductive fiber structure. Copper-tin-plated dot buttons were used to evaluate the metal corrosiveness of conductive fiber structures. The properties of the materials used and the obtained conductive fiber structure are shown in Table 1, and the results of elemental analysis are shown in Table 2. Since the obtained conductive fiber structure contains 1% or more of sulfur element and has a high value of metal corrosiveness, the obtained conductive fiber structure has metal corrosiveness and cannot be stored for a long period of time as an electrode member.

[Comparative Example 3]
94 g / m of "Denatron (registered trademark)" FB308B (manufactured by Nagase ChemteX Corporation, a mixed solution of a polythiophene-based conductive polymer and a binder) was added to the conductive fiber structure obtained by performing the same treatment as in Example 1. ² coatings were applied and dried and heat-treated at 130 ° C. for 5 minutes to obtain a conductive fiber structure. Copper-tin-plated dot buttons were used to evaluate the metal corrosiveness of conductive fiber structures. The properties of the materials used and the obtained conductive fiber structure are shown in Table 1, and the results of elemental analysis are shown in Table 2. Since the obtained conductive fiber structure contains 1% or more of sulfur element and has a high value of metal corrosiveness, the obtained conductive fiber structure has metal corrosiveness and cannot be stored for a long period of time as an electrode member.

[Comparative Example 4]
"Denatron (registered trademark)" FB308B (manufactured by Nagase ChemteX Corporation, a mixed solution of a polythiophene-based conductive polymer and a binder) was added to a knitted fabric as a base fiber obtained by performing the same treatment halfway as in Example 1. 350 g / m ^{2 was} applied and dry heat treated at 130 ° C. for 5 minutes, and then Denatron coating and dry heat treatment were repeated once again to obtain a conductive fiber structure. Copper-tin-plated dot buttons were used to evaluate the metal corrosiveness of conductive fiber structures. The properties of the materials used and the obtained conductive fiber structure are shown in Table 1, and the results of elemental analysis are shown in Table 2. Since the obtained conductive fiber structure contains 1% or more of sulfur element and has a high value of metal corrosiveness, the obtained conductive fiber structure has metal corrosiveness and cannot be stored for a long period of time as an electrode member.

1: Conductive fiber structure 2: Single fiber
3: Conductor

Claims (6)

A conductive fiber structure in which a conductor made of a conductive substance and a binder is attached to a base fiber, the conductive substance is carbon black, and the conductor is a single fiber constituting the base fiber. A conductive fiber structure supported on the surface and in the gap between the single fiber and the single fiber, wherein the mass concentration of sulfur elements in the surface layer of the conductive fiber structure is 1% by mass or less. .. The conductive fiber structure according to claim 1, wherein all or a part of the single fibers contained in the base fiber has a fiber diameter of 5 μm or less. The conductive fiber structure according to claim 1 or 2, wherein the mass concentration of the metal in the surface layer of the conductive fiber structure is 1% by mass or less. The conductive fiber structure according to any one of claims 1 to 3, wherein the volume resistivity is 1 × 10 ⁶ Ω · cm or less. The conductive fiber structure according to any one of claims 1 to 4, which is used as an electrode member constituting a bioelectrode. An electrode member for a bioelectrode, which comprises using the conductive fiber structure according to any one of claims 1 to 5.