JP2017168437A - Paste for forming flexible conductor, flexible conductor sheet and probe for measuring organism information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high durability flexible conductor sheet usable in a part directly contacting with body.SOLUTION: A carbon paste having predetermined voids is obtained by mixing and dispersing carbon-based conductive particles, preferably inorganic particles of which a surface is treated by hydroxide and/or oxide of one or both of Al and Si, a flexible resin and a solvent by 3 roll mills or the like, pasting them without a defoaming treatment and applying the same to a base agent and drying them. The resulting paste is printed, applied and dried to obtain a flexible conductor sheet for body contact electrode excellent in compressive resistance and washing resistance.SELECTED DRAWING: None

Description

The present invention relates to a sheet-like stretchable conductor sheet that can be laminated on a stretchable base material, and a paste for forming a stretchable conductor composition that becomes a stretchable conductor layer of the stretchable conductor sheet. The present invention relates to a probe for detecting biological information using a sheet.

In recent years, wearable electronic devices have been developed that are intended to use electronic devices having input / output, calculation, and communication functions in close proximity to or close to the body. As wearable electronic devices, devices having an accessory-type outer shape such as a wristwatch, glasses, and earphones, and textile integrated devices in which electronic functions are incorporated into clothes are known.

Electronic equipment requires electrical wiring for power supply and signal transmission. In particular, in textile-integrated wearable electronic devices, the electrical wiring is required to be stretchable in accordance with the stretchable clothes. Usually, electrical wiring made of metal wires or metal foils is not practically elastic, so the metal wires or metal foils are placed in a corrugated or repeated horseshoe shape to give a pseudo expansion / contraction function. The method is used.
In the case of a metal wire, wiring can be formed by regarding the metal wire as an embroidery thread and sewing it onto clothes. However, as described above, it is obvious that this method is not suitable for mass production because the elasticity of the metal is not insufficient.

A method of forming a wiring by etching a metal foil is a general method for producing a printed wiring board. A technique is known in which a metal foil is bonded to a stretchable resin sheet and a corrugated wiring is formed by a technique similar to that of a printed wiring board to make a pseudo stretchable wiring (see Non-Patent Document 1). This method is to give a pseudo expansion / contraction characteristic by twisting deformation of the corrugated wiring part, but the metal foil also changes in the thickness direction due to twisting deformation, so it is very uncomfortable when used as part of clothing. A certain feeling of wearing was not preferable. In addition, when subjected to excessive deformation as in washing, permanent plastic deformation occurs in the metal foil, and there is a problem in the durability of the wiring.

On the other hand, as a technique for realizing a stretchable conductor wiring, a method using a special conductive paste has been proposed. Kneaded with carbon-based conductive particles such as silver particles, carbon particles, carbon nanotubes, and elastic elastomers such as urethane resin, natural rubber, synthetic rubber, solvent, etc. to make a paste, directly on clothes or stretchable The wiring is printed and drawn in combination with a film substrate or the like (see Non-Patent Document 2).
Macroscopically, a conductive composition comprising carbon-based conductive particles and a stretchable binder resin can realize a stretchable conductor. When viewed microscopically, the conductive composition obtained from such a paste is deformed at the binder resin portion when subjected to external force, and the conductivity is maintained within a range where the electrical chain of the carbon-based conductive particles is not interrupted. It's just The specific resistance observed macroscopically is higher than that of metal wires and metal foils, but the cured product of the composition itself has elasticity, so there is no need to take the shape of corrugated wiring, etc. Since the thickness has a high degree of freedom, it is practically possible to realize a low resistance wiring compared to a metal wire.

As such a technique, Patent Document 1 discloses a technique for suppressing a decrease in conductivity during elongation by combining silver particles and silicone rubber, and further covering the conductive film on the silicone rubber substrate with silicone rubber. ing. Patent Document 2 discloses a combination of silver particles and a polyurethane emulsion, and it is said that a conductive film having high conductivity and high elongation can be obtained.
Furthermore, many examples have been proposed in which characteristics are improved by combining high-aspect ratio carbon-based conductive particles such as carbon nanotubes and silver fillers.

JP 2007-173226 A JP 2012-54192 A

Jong-Hyun Ahn and Jung Ho Je, "Stretchable electronics: materials, architectures and integrations" J. Phys. D: Appl. Phys. 45 (2012) 103001 Kyoung-Yong Chun, Youngseok Oh, Jonghyun Rho, Jong-Hyun Ahn, Young-Jin Kim, Hyoung Ryeol Choi and Seunghyun Baik, "Highly conductive, printable and stretchable composite films of carbon nanotubes and silver" Nature Nanotechnology, 5,853 ( 2010)

  The present invention is capable of forming a wiring with high accuracy on a stretchable base material such as a fabric, and has a surface layer having a sufficient protection function against contamination from the human body, and is a clothes such as washing and drying. Stretchable conductor sheet having resistance to normal use as a paste, and a paste for forming a stretchable conductor composition using carbon-based conductive particles applicable to a method for forming an electrical wiring of a clothes-type electronic device using the same, so-called It is to provide a stretchable carbon paste.

    However, in a composition in which such carbon-based conductive particles are blended with a resin, the carbon-based conductive particles are oriented depending on the coating direction. For example, the surface direction light coating direction and the vertical direction (XY direction) The anisotropic expansion and contraction may cause anisotropic conductive characteristics. When such anisotropy occurs, there is a risk that the linearity of the signal is lowered when the composition is applied to a displacement sensor using a resistance change. In addition, the wiring pattern formed on the clothes often has a two-dimensionally complicated shape, and when the necessary part is cut out from the stretchable conductor sheet and used as wiring, the sheet characteristics are anisotropic, There is a problem that the arrangement of patterns is limited and the productivity of wiring obtained from the sheet is lowered.

  Further, for example, when the stretchable conductor sheet is repeatedly twisted, the specific resistance of the sheet increases, and there is a possibility that the electrical signal corresponding to the motion of the subject is not appropriately reflected.

  Furthermore, in a composition in which such carbon-based conductive particles are blended with a resin, durability against deformation such as stretching, compression, and twisting during washing, which is unavoidable when applied to electrical wiring on clothes, becomes a problem. . For example, the electrical wiring during washing is forced to undergo large deformations such as repeated stretching, compression, and twisting by an external force in an aqueous medium containing a surfactant, and there is a problem that the conductivity of the stretchable conductor sheet decreases. there were.

Accordingly, an object of the present invention is to provide a stretchable conductor sheet that exhibits isotropic conductivity when stretched in a predetermined direction or a direction perpendicular thereto, and a stretchable conductor sheet forming paste used therefor. In the present specification, the predetermined direction means the direction of application of the stretchable conductor sheet forming paste, and the vertical direction means the direction perpendicular to the direction of application of the stretchable conductor sheet forming paste.
Another object of the present invention is to provide a stretchable conductor sheet having a small change in specific resistance even when it is repeatedly twisted and a paste for forming a stretchable conductor sheet used therefor.
Furthermore, an object of the present invention is to provide a stretchable conductor sheet having a small change in specific resistance even after repeated washing and a paste for forming a stretchable conductor sheet used therefor.

As a result of intensive studies to achieve the above object, the present inventors have found that the above problems can be solved by the following means, and have completed the present invention. That is, the present invention has the following configuration.
[1] A stretchable conductor sheet made of a stretchable conductor composition having at least carbon-based conductive particles and a flexible resin having a tensile modulus of elasticity of 1 MPa to 1000 MPa, and the porosity of the stretchable conductor sheet is 3 volumes. A stretchable conductor sheet characterized by being no less than 50% and no more than 50% by volume.
[2] Carbon conductive particles, inorganic particles having an aspect ratio of less than 1.5, an average particle size of 0.5 times or less of the aggregated silver particles, and a flexible resin having a tensile modulus of 1 MPa to 1000 MPa , A stretchable conductor sheet having a thickness of 3 to 800 μm, wherein the specific resistance after repeating 10% compression 100 times is within 2.4 times the initial specific resistance. Conductive sheet.
[3] The elastic conductor sheet [4] according to [1] or [2], wherein the inorganic particles are surface-treated with one or both of hydroxides and / or oxides of Al and Si. The stretchable conductor sheet according to any one of [1] to [3], wherein the compounding amount of the particles is 0.3 to 5.0% by mass with respect to the total mass of the stretchable conductor sheet.
[5] A paste for forming a stretchable conductor composition used for producing the stretchable conductor sheet according to any one of [1] to [4], comprising at least carbon-based conductive particles and an aspect ratio Is less than 1.5 and contains an inorganic particle having an average particle diameter of 1 μm or less, a flexible resin having a tensile elastic modulus of 1 MPa or more and 1000 MPa or less, and a solvent. A paste for forming a stretchable conductor sheet, which is 2.0 to 30% by mass in 100% by mass of the total of the conductive particles and the inorganic particles.
[6] The change rate of the specific resistance at the time of extension in the extension direction when 40% of the original length is extended in both directions perpendicular to the plane direction is less than ± 10% [1] ] To [4], the stretchable conductor sheet.
[7] The specific resistance of the sheet after repeating the twist cycle of the following twist test 100 times is within 3.0 times the initial specific resistance. The stretchable conductor sheet according to any one of the above.
[Torsion test: Sample: width 10 mm, length 100 mm (fixed at one end in the longitudinal direction of the sample, twisted by rotation of the other end) Twisting cycle: twisted 10 times in the positive direction (3600 °), returning to the initial state, negative direction 10 rotations (-3600 °) twist, return to initial state]
[8] The elastic resin binder according to any one of [1] to [4], [6], and [7], wherein the flexible resin is a stretchable polymer binder that does not substantially contain an organic sulfur compound. Stretchable conductor sheet.
[9] The flexible resin is a stretchable polymer binder that does not substantially contain an organic sulfur compound, and the content of the organic sulfur compound in the component excluding the solvent is 500 ppm in terms of sulfur. The paste for forming a stretchable conductor composition according to [5], which is characterized by the following.
[10] The stretchable conductor sheet according to any one of [1] to [4] and [6] to [8], which is used in the vicinity of a material containing silver.
[11] A single amount containing at least butadiene in which the stretchable polymer binder substantially free of organic sulfur compound is present in the presence of a surfactant not containing sulfur element and a chain transfer agent not containing sulfur element The paste for forming a stretchable conductor composition according to [5] or [9], wherein the paste is an aqueous polymer.
[12] A single amount containing at least butadiene in which the stretchable polymer binder substantially free of an organic sulfur compound is present in the presence of a surfactant not containing sulfur element and a chain transfer agent not containing sulfur element The elastic conductor sheet according to any one of [1] to [4], [6] to [8], and [10], characterized in that the body is an aqueous polymer.
[13] A probe for measuring biological information, characterized in that the stretchable conductor sheet according to [12] is used in a part that contacts the skin or mucous membrane of a living body.

Furthermore, the present invention preferably has the following configuration.
[14] A method for producing a paste for forming a stretchable conductor composition, characterized in that the defoaming operation is not performed and the contact portion according to claim 9 or 11 is used.

  The stretchable conductive sheet of the present invention contains 3% to 50% void-specific voids or inorganic particles in the volume fraction of the composition or sheet. Usually, in a conductive composition containing a conductive filler and a binder resin, voids and non-conductive inorganic particles impede conductivity, so a very small amount of nano-sized silica particles are added for the purpose of improving printing characteristics. Apart from that, it is usually not preferred to use. However, if it comes to the place which the present inventors discovered, by providing a specific space | gap, when a composition thru | or a sheet | seat is compressively deformed, a space | gap will absorb the distortion of a solid part and a resin part will deform | transform by external force. In doing so, it is possible to obtain an effect of reducing stress concentration at a specific location.

  Further, according to the present invention, since the inorganic particles surface-treated with one or both of Al and Si hydroxides and / or oxides, the dispersibility of the inorganic particles in the flexible resin is increased. Functions as a key point of resin deformation when deformed by external force, and when the external force is removed and shrinks, the resin tries to shrink with the key as a local center. This makes it easier to restore a shape close to the state before stretching.

  It is widely known that a stretchable conductor composition containing a conductive filler and a binder resin generally produces a conductive anisotropy depending on the direction depending on the direction of extrusion or coating in forming a sheet. Efforts have been made to minimize the anisotropy of conductivity by engineering measures such that the anisotropy of conductivity is usually negligible. However, it has been found that the electrical conductivity of the sheet obtained from the stretchable conductor composition is lowered by the accumulation of the interruption of the conductive path due to the microcracks generated during stretching. Such microcracks tend to occur in the direction perpendicular to the extension direction when first extended. When the film is stretched in a different direction after the second time, the deformation in the different direction is alleviated by the deformation centered on the first microcrack. For this reason, once the sheet or film of the stretchable conductor composition is stretched, as a result, anisotropy occurs in the conductivity.

  As a result, the coexistence of voids or specific inorganic particles can suppress the occurrence of microcracks during the initial stretching deformation of the stretchable conductor coating, and further the inorganic particles disperse the direction of microcracks, As a result, an excellent effect that the anisotropy in the XY direction is significantly improved is exhibited.

  Further, according to the present invention, it is possible to efficiently produce wiring such as horseshoe-shaped wiring (corrugated wiring) from an elastic conductor sheet having isotropic conductivity.

  In addition, according to the present invention, the change in specific resistance can be reduced even if the twist is repeatedly received. The effect (torsion resistance) is considered to be manifested by the following mechanism of action. In other words, when the resin part is deformed in two dimensions by twisting, the inorganic particles function as the key to the resin deformation (the key), and when the deformation stretched in the plane direction is restored to the original state, the key is the local center As the resin returns to the initial state, the anisotropy of restoration is reduced. When this is expanded to three-dimensional deformation, the same effect is exhibited in the thickness direction by using inorganic particles having a smaller aspect ratio, and the three-dimensional deformation such as torsion is also observed. Inorganic particles function as the key to the deformation of the resin (the key), and when the twist is removed, the resin returns to the initial state with the key as the local center, so the shape is closer to the state before twisting than when there is no key For example, the restoring force after twisting in a predetermined direction (for example, positive direction) becomes equal to the restoring force after twisting in the direction opposite to the predetermined direction (for example, negative direction). Therefore, even when twisting is repeatedly applied during washing or wearing, the change in specific resistance can be reduced.

  On the other hand, when the stretchable conductor sheet of the present invention is a horseshoe-shaped wiring (corrugated wiring) (see FIG. 6), the deformation is absorbed not by stretch resistance but by twist resistance, so that the stretch rate is substantially low. It will be suppressed and the stretch durability will be further improved.

  Furthermore, the present inventors have observed many cases where the conductivity is lowered when clothes having electrical wiring obtained from the stretchable conductor sheet are washed. The present inventors have determined that such a decrease in conductivity is caused by fine cracks generated in the stretchable conductor sheet, dropout / deletion of a part of the stretchable conductor sheet, and further, a part of the stretchable conductor sheet. It was found that the dropout was due to buckling failure during compression of the elastic conductor sheet. Based on these findings, combining predetermined agglomerated silver particles and inorganic particles can impart compression resistance to the stretchable conductor sheet, and also improve the washing resistance, which is a practical characteristic.

  Furthermore, the stretchable conductor sheet of the present invention preferably includes a predetermined range of voids inside. Usually, in a conductive composition containing a conductive filler and a matrix resin, such voids are not preferred because they impede conductivity. However, the present inventors have also found that a moderately controlled void exhibits a mechanical buffering effect that absorbs compressive deformation and prevents buckling failure during compression. As a result, the change in specific resistance when repeatedly subjected to compression deformation can be reduced (that is, compression resistance can be imparted), and washing resistance can also be improved.

FIG. 1 is a diagram showing an example of a method for forming a stretchable conductor sheet of the present invention on a fabric by a direct printing method. FIG. 2 is a diagram showing an example of a method for forming the stretchable conductor sheet of the present invention on a fabric by a transfer method. FIG. 3 is a diagram in which a wiring made of the stretchable conductor sheet of the present invention is formed on a glove-type device. FIG. 4 is a diagram showing an example of wiring formed by the stretchable conductor sheet of the present invention. FIG. 5 is a diagram showing an example in which the wiring of FIG. 4 is used for a shirt. FIG. 6 is a diagram showing an example of a horseshoe-shaped wiring formed from the stretchable conductor sheet of the present invention.

The present invention is a stretchable conductor sheet containing carbon-based conductive particles, flexible resin, voids, preferably inorganic particles, wherein the inorganic particles are one or both of Al and Si hydroxides and / or oxides. And the sheet has a specific resistance change rate of less than ± 10% when stretched in the stretching direction when the sheet is stretched by 40% of the original length in two orthogonal directions. There is a special feature.
Further, the present invention is a stretchable conductor sheet containing carbon-based conductive particles, flexible resin, and preferably voids, or preferably inorganic particles, the aspect ratio of the inorganic particles is less than 1.5, The sheet is characterized in that the specific resistance of the sheet after repeating the twist cycle of the twist test 100 times is within 3.0 times the initial specific resistance.
Further, the present invention is a stretchable conductor sheet containing aggregated silver particles, a flexible resin, and preferably voids, or preferably inorganic particles, wherein the average particle diameter of the aggregated silver particles is 0.8 to 10 μm, and inorganic The aspect ratio of the particles is less than 1.5, the average particle diameter of the inorganic particles is 0.5 times or less of the aggregated silver particles, and the specific resistance after repeating 10% compression 100 times is 2 of the initial specific resistance. There is a special feature in that it is within 4 times.

Hereinafter, each component used for the stretchable conductor sheet and the paste for forming the stretchable conductor sheet will be described.
The conductive filler used in the stretchable conductor sheet and the paste for forming a stretchable conductor in the present invention is carbon-based particles. As the carbon particles in the present invention, graphite powder, activated carbon powder, scaly graphite powder, acetylene black, ketjen black, fullerene, single-walled carbon nanotube, multi-walled carbon nanotube, carbon nanocone, and the like can be used. In the present invention, preferably used carbon-based particles are graphite powder, scaly graphite powder, activated carbon powder, and ketjen black. In the present invention, it is further preferable to use carbon-based particles having a BET specific surface area of 1000 m ² / g or more.

  The carbon-based particles in the present invention can be blended in an amount of 18 to 60% by mass with respect to the total mass of the carbon-based particles and the binder. The carbon-based particles in the present invention are preferably contained in an amount of 30% by mass or more based on the total mass of the carbon-based particles and the binder, more preferably 33% by mass or more, and further preferably 36% by mass or more. Furthermore, it is preferable to contain 39 mass% or more. When the content of the carbon-based particles is less than the predetermined range, not only necessary conductivity but also a protective function for the covered layer is deteriorated. On the other hand, if the content exceeds this range, the elongation at break of the film decreases.

The composition constituting the first stretchable conductor layer of the present invention preferably contains 4% by mass or more, more preferably 6% by mass or more of carbon-based particles having a BET specific surface area of 1000 m ² / g or more. Preferably, it is further preferable to contain 8% by mass or more. By blending carbon-based particles having a BET specific surface area of 1000 m @ 2, the protective function of the cover layer is significantly improved.

The porosity in the present invention can be led to a predetermined range by not actively performing a defoaming operation in the manufacturing process. In general, a conductive paste produced by mixing and dispersing using an attritor, a sand mill, a three-roll mill, or the like contains bubbles caused by air entrained during kneading. In addition, when such a conductive paste is dried and cured to form a conductive sheet, bubbles generated in the process of volatilization of the solvent are added in addition to the bubbles entrained during paste manufacture. Furthermore, in order to increase the contact probability between the conductive particles, the amount of the binder resin used is suppressed to the minimum necessary, so that bubbles tend to remain in the conductive film of such a dispersion system.
Therefore, in such a paste manufacturing process, a foam removal process is often performed using a self-revolving mixer that is not a centrifugal type. In the present invention, the void ratio is realized by not actively removing bubbles and setting the ratio of the binder resin to the inorganic solid content of the conductive paste slightly smaller.
In the present invention, when the specific gravity ratio of the actually measured sheet coating is 100% of the calculated specific gravity of the stretchable conductor sheet calculated with a carbon specific gravity of 2.2 and a resin specific gravity of 1.25, It is preferable to control to 70 to 95%. The specific gravity may be actually measured from the thickness and area of the sheet cut into an arbitrary size and the mass of the sheet.

<Inorganic particles>
The inorganic particles of the present invention are surface-treated with one or both of hydroxides and / or oxides of Al and Si. Such inorganic particles contribute to an improvement in dispersibility in a flexible resin, and can exhibit isotropic properties when stretched in different directions. This isotropic conductivity is considered to be manifested by the following mechanism action.
In other words, when the resin part is deformed by an external force, the inorganic particles function as a key for resin deformation, and when the external force is removed and the resin part shrinks, the resin tends to contract with the key as a local center. Compared to the case where no is present, it is easy to restore to a shape close to the state before expansion / contraction, for example, the restoring force after expansion / contraction in the X direction becomes equal to the restoring force after expansion / contraction in the Y direction. Therefore, even when expansion or contraction in a specific direction at the time of washing or wearing is applied, the conductivity in the Y direction after expansion or contraction in the X direction does not decrease, and isotropic conductivity can be exhibited. Similarly, inorganic particles can contribute to torsion resistance.

  Furthermore, by blending such inorganic particles, the filler content (conducting particles, inorganic particles, When the conductive film and the conductive sheet are obtained by drying and curing the paste by increasing the void volume in the apparent volume of the solid component in the paste stage without being dissolved in the solvent, The effect of stably realizing a predetermined porosity is exhibited.

  Examples of the inorganic particles include particles such as barium sulfate, titanium oxide, and zinc oxide. Among these, particles of barium sulfate and titanium oxide are preferable from the viewpoints of particle size control and surface treatment. As barium sulfate particles, barium sulfate, which is a pulverized product of barite mineral called natural barite, and so-called precipitated barium sulfate produced by a chemical reaction can be used. It is preferable to use precipitated barium sulfate which can easily control the particle size. Titanium oxide may be any of anatase type, rutile type or brookite type.

For the surface treatment, a conventionally known method can be employed. For example, a substance that can be one or both of Al and Si hydroxides and / or oxides is added to an inorganic particle-containing solution slurry and heated. . Examples of the hydroxide and / or oxide of one or both of Al and Si include oxides such as SiO 2 and Al 2 O 3, hydroxides such as Al (OH) 3 and Si (OH) 4, and the like.
Examples of the substance that can be a hydroxide and / or oxide of one or both of Al and Si include sodium silicate and sodium aluminate. What is necessary is just to dripped at the inorganic particle containing solution slurry as aqueous solution when using these.
A solution of a substance that can be one or both of Al and Si hydroxides and / or oxides is dropped into the inorganic particle-containing solution slurry, and the mixture is heated (for example, 40 to 100 ° C., preferably 50 to 90 ° C.). By neutralizing with an acid (for example, dilute sulfuric acid) and drying, one or both of hydroxides and / or oxides of Al and Si adhere to the surface of the inorganic particles.

The inorganic particles are preferably surface-treated with at least one selected from SiO2 and Al2O3, and more preferably surface-treated with SiO2 and Al2O3.
The deposition amount of SiO2 and Al2O3 is preferably 0.2% by mass or more and 5% by mass or less, and 0.5% by mass or more and 4% by mass or less in the total mass of 100% by mass of the inorganic particles and the amount of the surface treatment material. It is more preferable that
Further, the deposition amount of Si and Al is preferably 0.5 to 50, more preferably 2 to 30 with respect to the barium element 100 in terms of element ratio by fluorescent X-ray analysis.

The average particle diameter obtained by the dynamic light scattering method of inorganic particles is preferably 0.01 to 18 μm, more preferably 0.03 to 12 μm, still more preferably 0.05 to 8 μm, and still more preferably 0.1 to 0.1 μm. It is 5 μm, particularly preferably 0.2 to 3 μm.

The blending amount of the inorganic particles is preferably 0.3 to 5.0% by mass, and more preferably 1.0 to 2.0% by mass with respect to the total mass of the stretchable conductor sheet. If the blending amount of the inorganic particles exceeds this range, the conductivity of the obtained coating film surface is lowered, and the stretchability may be lowered. On the other hand, if the blending amount of the inorganic particles is smaller than this range, the isotropic conductivity is hardly exhibited. Moreover, when the compounding quantity of an inorganic particle is smaller than this range, it will become difficult to express twisting resistance. Furthermore, if the blending amount of the inorganic particles is smaller than this range, the compression resistance is hardly exhibited.

  The aspect ratio of the inorganic particles is preferably less than 1.5, more preferably 1.4 or less, and further preferably 1.3 or less. When it is 1.5 or more, the restoring force upon expansion / contraction by the surface-treated inorganic particles becomes difficult to show isotropic property, and there is a possibility that isotropic conductivity is not exhibited. The lower limit of the aspect ratio of the inorganic particles may be about 1.0, for example.

Examples of the flexible resin in the present invention include thermoplastic resins, thermosetting resins, rubbers and the like having a tensile modulus of 1-1000 MPa. In order to express the stretchability of the coating film (sheet), rubber is preferable. As rubber, urethane rubber, acrylic rubber, silicone rubber, butadiene rubber, nitrile group-containing rubber such as nitrile rubber and hydrogenated nitrile rubber, isoprene rubber, sulfurized rubber, styrene butadiene rubber, butyl rubber, chlorosulfonated polyethylene rubber, ethylene propylene Examples include rubber and vinylidene fluoride copolymer.
Among these, nitrile group-containing rubber, chloroprene rubber, chlorosulfonated polyethylene rubber and styrene butadiene rubber are preferable, and nitrile group-containing rubber and styrene butadiene rubber are particularly preferable. The tensile elastic modulus of the flexible resin is preferably 3 to 600 MPa, more preferably 10 to 500 MPa, further preferably 15 to 300 MPa, still more preferably 20 to 150 MPa, and particularly preferably 25 to 100 MPa.

The rubber containing a nitrile group is not particularly limited as long as it is a rubber or elastomer containing a nitrile group, but nitrile rubber and hydrogenated nitrile rubber are preferred. Nitrile rubber is a copolymer of butadiene and acrylonitrile. If the amount of bound acrylonitrile is large, the affinity with metal increases, but the rubber elasticity contributing to stretchability decreases conversely. Therefore, the amount of bound acrylonitrile is preferably 18 to 50% by mass, more preferably 30 to 50% by mass, and more preferably 40 to 50% in 100% by mass of nitrile-containing rubber (for example, acrylonitrile butadiene copolymer rubber). It is particularly preferable that the content is% by mass.

In the styrene-butadiene rubber, the content ratio of styrene and butadiene (styrene / butadiene) is preferably 70/30 to 30/70, more preferably 60/40 to 40/60, based on mass.

Most of synthetic rubbers are generally collected as a resin by agglomerating latex polymerized by an aqueous polymerization process by a method such as salting out, washing, dehydrating and drying. The aqueous polymerization is a general term for emulsion polymerization, suspension polymerization, dispersion polymerization and the like. Emulsion polymerization is widely used industrially as a standard method for producing synthetic rubber. Academically, emulsion polymerization, suspension polymerization, and dispersion polymerization are distinguished depending on the type of emulsifier, the type of polymerization initiator, the type of monomer, etc., but in the industrial process, for the production efficiency, it is based on the solvent water. It is required to keep the ratio of the solute high, and it becomes difficult to strictly separate emulsion polymerization, suspension polymerization, and dispersion polymerization. In any case, a surfactant, a polymerization initiator, a polymerization initiator having surface activity, a chain transfer agent, or the like is used in the aqueous polymerization, and these auxiliary agents often contain a sulfur element. In the present invention, it is preferable to use an auxiliary agent and a process material having a low sulfur component as much as possible, and it is preferable to use an auxiliary agent containing no sulfur element and a synthetic rubber obtained by using the process material. More specifically, a surfactant containing a sulfonate group is not used as an emulsifier or a dispersant, a surfactant containing a carboxylate group or a phosphate group, preferably a fatty acid alkali metal salt, The use of synthetic rubbers obtained by using fatty acid amine salts, alkyl ether alkali metal phosphates, polyacrylates, polymethacrylates, derivatives thereof and the like as emulsifiers and dispersants is preferred. As chain transfer agents, avoid thiol compounds, secondary alcohols such as isopropyl alcohol; phosphorous acid, hypophosphorous acid and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), α-methyl It is preferable to use styrene dimer, carbon tetrachloride or the like. In the case of highly water-soluble sulfite, sulfite, etc., it can be reduced by sufficiently washing with water, so that their combined use is allowed.

  The urethane resin of the present invention can be obtained by reacting a soft segment made of a polyether, polyester, or polycarbonate polyol with a hard segment made of diisocyanate or the like. As the soft segment component, a polyester polyol is more preferable because of the degree of freedom in molecular design.

  Examples of the polyether polyol in the present invention include copolymerization of monomer materials such as polyethylene glycol, polypropylene glycol, polypropylene triol, polypropylene tetraol, polytetramethylene glycol, polytetramethylene triol, and cyclic ether for synthesizing these. Examples thereof include polyalkylene glycols such as copolymers, derivatives obtained by introducing side chains or branched structures, modified products, and mixtures thereof. Of these, polytetramethylene glycol is preferred. The reason is that the mechanical properties are excellent.

  As the polyester polyol in the present invention, aromatic polyester polyol, aromatic / aliphatic copolymer polyester polyol, aliphatic polyester polyol, and alicyclic polyester polyol can be used. As the polyester polyol in the present invention, either a saturated type or an unsaturated type may be used. Of these, aliphatic polyester polyols are preferred.

  A commercial item can also be used as said aliphatic polyester polyol. Specific examples of commercially available products include, for example, Polylite ODX-688, ODX-2044, ODX-240 (manufactured by DIC), Kuraray polyol P-2010, P-2050, P-1010 (Kuraray), Teslac 2461, 2455, 2469 (manufactured by Hitachi Chemical).

Examples of the polycaprolactone diol in the present invention include polycaprolactone diol compounds obtained by ring-opening addition reaction of lactones such as γ-butyllactone, ε-caprolactone, and δ-valerolactone.

Examples of commercially available polycarbonate diol compounds that can be used in the present invention include Kuraray Kuraray Polyol C Series, Asahi Kasei Chemicals Duranol Series, and the like. For example, Kuraray polyol C-1015N, Kuraray polyol C-1065N, Kuraray polyol C-2015N, Kuraray polyol C2065N, Kuraray polyol C-1050, Kuraray polyol C-1090, Kuraray polyol C-2050, Kuraray polyol C-2090, DURANOL- Examples thereof include T5650E, DURANOL-T5651 and DURANOL-T5652.

  As the diisocyanate compound in the present invention, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, m-phenylene diisocyanate, 3,3′-dimethoxy-4 , 4′-biphenylene diisocyanate, 2,6-naphthalene diisocyanate, 3,3′-dimethyl-4,4′-biphenylene diisocyanate, 4,4′-diphenylene diisocyanate, 4,4′-diisocyanate diphenyl ether, 1,5- Aromatic diisocyanates such as naphthalene diisocyanate and m-xylene diisocyanate, or 1,6-hexane diisocyanate, isophorone diisocyanate, 4,4′-diphenylmethane diisocyanate DOO, hydrogenated xylylene diisocyanate (ortho, meta, para) aliphatic, and alicyclic diisocyanates. Among these, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and isophorone diisocyanate are preferable. Moreover, you may use together the said isocyanate combined use and the polyfunctional compound more than trifunctional as needed.

If necessary, the polyurethane resin of the present invention may be copolymerized with a diol compound or the like generally called a chain extender.
Examples of the diol compound used as a chain extender include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propanediol, and 2-methyl-1,3-propanediol. 2-methyl-2-propyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3-propanediol, 1,2- Butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,5- Pentanediol, 2,2,4-trimethyl-1,3-pentanediol, neope Tyl glycol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 1,8-octanediol, 2-methyl-1,8-octane Examples include diols and aliphatic glycols such as 1,9-nonanediol. Alternatively, low molecular weight triols such as trimethylolpropane and triethanolamine, diamine compounds such as diethylamine and 4,4′-diaminodiphenylmethane, and trimethylolpropane can be used. Among these, 1,6-hexanediol is particularly preferable.

The glass transition temperature of the polyurethane resin of the present invention is preferably 0 ° C. or lower, more preferably −60 ° C. or higher and −10 ° C. or lower, and most preferably −50 ° C. or higher and −20 ° C. or lower. When the glass transition temperature exceeds 0 ° C., the elongation of the produced conductive coating film becomes small, and the resistance increase at the time of elongation may be deteriorated. Moreover, when it is less than -60 degreeC, there exists a possibility that the produced electrically conductive film may produce blocking. The reduced viscosity is from 0.2 dl / g to 3.0 dl / g, preferably from 0.3 dl / g to 2.5 dl / g, more preferably from 0.4 dl / g to 2.0 dl / g. It is. If it is less than 0.2 dl / g, the conductive coating film becomes brittle and there is a risk that the resistance increase at the time of elongation will worsen. Moreover, when it exceeds 3.0 dl / g, there exists a possibility that the solution viscosity of a polyurethane resin composition may become high and handling may become difficult.

When a polyurethane resin is produced, stannous octylate, dibutyltin dilaurate, triethylamine, bismuth metal, or the like may be used as a catalyst.

  The blending amount of the flexible resin is preferably 7 to 35% by mass, more preferably 8 to 30% by mass, and still more preferably 9% in the total 100% by mass of the carbon-based conductive particles, the inorganic particles, and the flexible resin. -25% by mass, and more preferably 10-22% by mass. When the blending amount of the flexible resin is small, the stretchability of the conductor sheet is lowered and the stretch durability may be lowered. When the blending amount of the flexible resin is large, the conductivity is lowered and the isotropic conductivity may be lowered.

As a method for producing the stretchable conductor sheet of the present invention, the composition (excluding the solvent) constituting the stretchable conductor sheet is melt-kneaded and compounded at a temperature at which the flexible resin component is sufficiently softened, and melt extrusion is performed. A method of forming a film by a machine can be exemplified. This method is preferably used when high productivity is required.
As a method for producing the stretchable conductor sheet of the present invention, the material constituting the stretchable conductor sheet is further blended with a solvent capable of dissolving and dispersing the flexible resin component, and after processing into a slurry or paste, The manufacturing method which makes it a sheet | seat by apply | coating and drying to a support body can be illustrated.

  One of the aspects of the present invention is a paste for forming a stretchable conductor sheet used for producing a stretchable conductor sheet, and at least carbon-based conductive particles, preferably water of one or both of Al and Si. An inorganic particle surface-treated with an oxide and / or an oxide, a flexible resin having a tensile modulus of 1 MPa to 1000 MPa, and a solvent, and the compounding amount of the inorganic particle is the carbon-based conductive particle The total amount of the inorganic particles is 2.0 to 30% by mass, and the amount of the flexible resin is 100% by mass of the carbon-based conductive particles, the inorganic particles, and the flexible resin. 7 to 35% by mass of a paste for forming a stretchable conductor sheet.

  The paste for forming a stretchable conductor sheet of the present invention contains a solvent. The solvent in the present invention is preferably water or an organic solvent. Since the content of the solvent should be appropriately adjusted depending on the viscosity required for the paste, there is no particular limitation, but when the total mass of carbon-based conductive particles, inorganic particles, flexible resin and solvent is 100% It is preferably 20 to 60% by mass, more preferably 22 to 50% by mass, and still more preferably 24 to 40% by mass.

  In the organic solvent, the boiling point is preferably 100 ° C. or more and less than 300 ° C., more preferably the boiling point is 130 ° C. or more and less than 280 ° C. If the boiling point of the organic solvent is too low, the solvent volatilizes during the paste manufacturing process or when the paste is used, and there is a concern that the component ratio constituting the paste is likely to change. On the other hand, if the boiling point of the organic solvent is too high, the amount of residual solvent in the dry cured coating film increases, and there is a concern that the reliability of the coating film is reduced.

Examples of the organic solvent include ester solvents, ether solvents, ether ester solvents, ketone solvents, alcohol solvents, and aromatic hydrocarbon solvents. Examples of the ester solvent include γ-butyrolactone and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate.
Examples of ether solvents include diethylene glycol, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol, tetraethylene glycol monobutyl ether, tripropylene glycol, tripropylene glycol monomethyl. Examples include ether. Examples of the ether ester solvent include propylene glycol monomethyl ether acetate, butyl glycol acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoacetate, and triethylene glycol diacetate. Examples of the ketone solvent include cyclohexanone and isophorone.
Examples of the alcohol solvent include benzyl alcohol, terpionol, n-dodecanol and the like. Examples of the aromatic hydrocarbon solvent include toluene, xylene, Exo Chemical's Solvesso 100, 150, 200, diamylbenzene, triamylbenzene, and the like.

  As petroleum-based hydrocarbons, AF Solvent No. 4 (boiling point: 240-265 ° C.), No. 5 (boiling point: 275-306 ° C.), No. 6 (boiling point: 296-317 ° C.) manufactured by Nippon Oil Corporation , No. 7 (boiling point: 259-282 ° C.), No. 0 solvent H (boiling point: 245-265 ° C.) and the like, and two or more of them may be included as necessary. Such an organic solvent is appropriately contained so that the stretchable conductor sheet forming paste has a viscosity suitable for printing or the like. Among these, isophorone is preferable from the viewpoint that the organic solvent is less likely to volatilize when the paste is prepared and the organic solvent is sufficiently volatilized when the paste is applied.

  Moreover, an epoxy resin can be mix | blended with the paste for stretchable conductor sheet formation of this invention. A preferable epoxy resin in the present invention is a bisphenol A type epoxy resin or a phenol novolac type epoxy resin. When blending an epoxy resin, an epoxy resin curing agent can be blended. A known amine compound, polyamine compound, or the like may be used as the curing agent. It is preferable that the compounding quantity of a hardening | curing agent is 1-30 mass parts with respect to 100 mass parts of epoxy resins, and it is more preferable that it is 2-15 mass parts. Moreover, the compounding quantity of an epoxy resin and a hardening | curing agent becomes like this. Preferably it is 0.5-30 mass parts with respect to 100 mass parts of flexible resins, More preferably, it is 1.0-20 mass parts, More preferably, it is 1.5-15 masses. Part.

  The stretchable conductor sheet forming paste of the present invention is a known organic material such as a leveling agent, an antioxidant, and an ultraviolet absorber, from the viewpoint of imparting printability and adjusting the color tone, as long as the content of the invention is not impaired. Inorganic additives can be blended.

  Composition by mixing carbon-based conductive particles, inorganic particles, and flexible resin with a solvent, and mixing and dispersing with a disperser such as a dissolver, triple roll mill, self-revolving mixer, attritor, ball mill, sand mill, etc. The paste for forming a stretchable conductor sheet can be prepared.

  As an example of an embodiment of the present invention, the paste for forming a stretchable conductor sheet obtained as described above is applied by a technique such as a die coater, a squeegee coater, an applicator, a comma coater, or screen printing (preferably by an applicator or a comma coater). Preferably, the stretchable conductor sheet can be obtained by using a solution film-forming method in which it is applied to a substrate having releasability and dried to form a sheet. This method can be produced even in a small amount, but is a preferable method when a relatively thin sheet is required.

  In order to apply the paste to the substrate, volatilize the solvent, and dry the substrate, for example, heating may be performed for a predetermined time in the air, in a vacuum atmosphere, in an inert gas atmosphere, in a reducing gas atmosphere, or the like. The heating temperature is, for example, 100 to 150 ° C, preferably 110 to 130 ° C. The heating time is, for example, 10 minutes to 40 minutes, preferably about 20 minutes to 30 minutes.

  The thickness of the stretchable conductor sheet obtained through the paste state is 3 μm to 800 μm, preferably 8 μm to 500 μm, more preferably 12 μm to 300 μm, and further preferably 20 μm to 180 μm. When the thickness of the sheet is less than 3 μm, durability against expansion and contraction is lowered, and there is a possibility that conductivity is lowered. When the thickness of the sheet is more than 800 μm, sufficient stretchability is difficult to obtain, and there is a possibility that sufficient fit cannot be obtained when used for a fabric.

  The stretchable conductor sheet of the present invention can be formed into a sheet by forming a stretchable conductor sheet forming paste alone (forming a conductive layer), and can be formed into a sheet having an insulating layer on at least one surface as necessary. It is preferable that the insulating layer has elasticity like the elastic conductor sheet. As a material for the insulating layer, a polymer material having a low elastic modulus is preferable as in the case of the flexible resin constituting the stretchable conductor sheet forming paste. When the stretchable conductor sheet is used as an electrical wiring, the insulating layer has a function as an adhesive layer between the stretchable conductor sheet and the base material. Further, when it is provided on the side opposite to the base material when it is used as electric wiring, that is, on the surface side, it functions as an insulating coat layer (insulating portion).

The resin forming the insulating layer is not particularly limited as long as it is an insulating resin, and examples thereof include polyurethane resins, silicone resins, vinyl chloride resins, and epoxy resins. Among these, polyurethane resins are preferable from the viewpoint of adhesiveness with the conductive layer.
The polyurethane-based resin is preferably, for example, a polyester-based polyurethane resin, a polyether-based polyurethane resin, or a polycarbonate-based polyurethane resin, and more preferably a polyester-based polyurethane resin from the viewpoint of stretchability of the coating film.

  The insulating layer is obtained by dissolving or dispersing a resin in a solvent (preferably water), applying or printing on a substrate or cloth fabric to form a coating film, and then volatilizing and drying the solvent contained in the coating film. May be prepared. At this time, the viscosity of the resin solution may be 400 mPa · s or less, and a thickener such as an acrylic polymer may be used as a viscosity modifier.

The film thickness of an insulating layer is 5-200 micrometers, for example, Preferably it is 8-150 micrometers, More preferably, it is 14-90 micrometers, More preferably, it is 20-70 micrometers. If the insulating layer is too thin, the insulating effect will be insufficient, and if the insulating layer is too thick, the stretchability of the fabric or the like may be hindered or the comfort may be hindered.
The insulating layer formed on the fabric is usually partially impregnated into the fabric, but the film thickness may be any thickness including the portion impregnated in the fabric. The film thickness of the insulating layer excluding the impregnated portion is, for example, 5 to 200 μm, preferably 8 to 150 μm, more preferably 14 to 90 μm, and further preferably 20 to 70 μm.

  If necessary, the stretchable conductor sheet of the present invention can be formed into a sheet in the form of a multilayer with another stretchable conductor layer mainly using a metal filler such as silver. The stretchable conductor sheet of the present invention is less irritating and stable to components such as sweat and body fluids derived from living organisms, and therefore can be used for electrode parts that come into contact with living body skin or mucous membranes. Therefore, the biological information measuring probe can be obtained using the stretchable conductor sheet of the present invention as a contact site.

Furthermore, in the present invention, the elastic conductor resin sheet may be attached to clothing or a cloth that is a raw material of the clothing to form the electrical wiring.
A known adhesive or hot melt resin may be used for attaching the sheet to the fabric. The material used for bonding is preferably flexible. Alternatively, the insulating layer sheet can be used as a hot-melt material by leaving the insulating layer sheet in a B-stage that is in a semi-dried and semi-cured state. It is also possible to bond the stretchable conductor sheet to the fabric by heating and pressurizing using the B stage.

  In the present invention, it is possible to produce a fabric having electrical wiring composed of a stretchable conductor sheet by directly printing an electrical wiring pattern on the fabric using the stretchable conductor sheet forming paste.

As a printing method, a screen printing method, a lithographic offset printing method, a paste jet method, a flexographic printing method, a gravure printing method, a gravure offset printing method, a stamping method, a stencil method, and the like can be used. It is preferable to use a stencil method. A method of directly drawing wiring using a dispenser or the like may be interpreted as printing in a broad sense.

Printing is a method of obtaining a textile product such as clothing by printing a predetermined pattern on a fabric such as a woven fabric, a knitted fabric, a nonwoven fabric, or synthetic leather, which is a raw fabric of clothing or textile product, and then cutting and sewing. It is also possible to print in the state of a finished textile product or a sewing intermediate.
Alternatively, the stretchable conductor sheet-forming paste can be printed on the fabric in advance or partially after a flexible resin material such as polyurethane resin or rubber is applied as a base. Alternatively, the cloth may be temporarily hardened with a water-soluble resin to facilitate handling for printing. Further, it may be temporarily fixed to a harder plate material for printing. Garment with wiring obtained by printing a paste for forming a stretchable conductor sheet directly on the fabric partially interpenetrates with the fabric fibers of which the base and / or stretchable conductor are the base material, realizing strong adhesion can do. In addition, even when printing through the underlayer, a stretchable conductor sheet forming paste and a material having good adhesiveness can be appropriately selected for the underlayer, so that it is possible to obtain a garment having an electric wiring layer having good adhesion. it can.

The wiring made of the stretchable conductor sheet of the present invention can be provided with a stretchable insulating cover coat by printing or laminating as necessary.
In the present invention, a fabric having stretchable wiring can be produced by printing an electrical wiring pattern on an intermediate medium using the above-described paste for forming a stretchable conductor sheet and transferring it to the fabric.

The isotropic conductivity of the stretchable conductor sheet of the present invention can be evaluated as follows. That is, the coating direction of the paste for forming the stretchable conductor sheet is A, the direction perpendicular to the coating direction is B, and the obtained stretchable conductor sheet is a test piece cut into a predetermined sample (width 20 mm, length 50 mm). Is used to measure the specific resistance at an elongation rate of 40%, and the change rate of the specific resistance in the coating direction (A) and the direction perpendicular to the coating direction (B) (also referred to as isotropic in the present specification). ) Can be obtained by the following equation.
Isotropic [%] = {(specific resistance in the coating direction / specific resistance in the direction perpendicular to the coating direction) -1} × 100

The elongation rate can be calculated by the following formula.
Elongation rate (%) = (ΔL0 / L0) × 100
L0 represents the distance between the marked lines of the test pieces, and ΔL0 represents the increase in the distance between the marked lines of the test pieces. In addition, the sheet resistance at the time of extension was read as a value 30 seconds after reaching a predetermined degree of extension.

The specific resistance may be measured as follows.
Thickness gauge SMD-565L (manufactured by TECLOCK) was used for the film thickness, and sheet resistance was measured for four test pieces using Loresta-GP MCP-T610 (manufactured by Mitsubishi Chemical Analytech), and the average value was used. The specific resistance can be calculated by the following equation.
Specific resistance (Ω · cm) = Rs (Ω □) × t (cm)
Rs represents the sheet resistance measured under each condition, and t represents the measured film thickness.

  In the present invention, the isotropy is evaluated by the specific resistance when the coating direction is 40% stretched and the specific resistance when the coating direction is 40% stretched in the direction perpendicular to the coating direction. That is, in both directions perpendicular to each other, the rate of change in the specific resistance when stretched in the stretched direction when stretched by 40% of the original length is less than ± 10%, and is ± 9.0% or less. Preferably, it is ± 8.0% or less, more preferably ± 7.5% or less.

The twist resistance of the stretchable conductor sheet of the present invention can be obtained by repeating the twist cycle of the twist test 100 times and calculating the change in specific resistance.
[Torsion test: Sample: width 10 mm, length 100 mm (fixed at one end in the longitudinal direction of the sample, twisted by rotation of the other end) Twisting cycle: twisted 10 times in the positive direction (3600 °), returning to the initial state, negative direction 10 rotations (-3600 °) twist, return to initial state]

  In the present invention, the specific resistance of the sheet after repeating the twist cycle of the torsion test 100 times is within 3.0 times, preferably within 2.8 times, more preferably within 2.times. It is within 6 times, more preferably within 2.4 times, even more preferably within 2.2 times, and particularly preferably within 2.0 times.

The compression resistance of the stretchable conductor sheet of the present invention can be determined by repeating 10% compression 100 times and calculating the change in specific resistance.
Specific resistance change (times) = specific resistance of stretchable conductor sheet with 10% compression repeated 100 times / specific resistance of stretchable conductor sheet in initial state

  In the present invention, the specific resistance of the stretchable conductor sheet after repeating 10% compression 100 times is within 2.4 times the initial specific resistance, preferably within 2.2 times, more preferably 2. Within 0 times, more preferably within 1.8 times. If the stretchable conductor sheet of the present invention falls within such a change in specific resistance after compression, it can be said that the sheet has sufficient compression resistance.

  The porosity of the stretchable conductor sheet of the present invention is preferably 3% by volume to 50% by volume, more preferably 4% by volume to 40% by volume, and still more preferably 5% by volume to 30% by volume. If the porosity is small, the compression resistance and washing durability may be reduced. On the other hand, if the porosity is large, the stretchability and conductivity may be reduced.

When the stretchable conductor sheet of the present invention is used for washing, the change in specific resistance after washing in the stretchable conductor sheet is small, and the washing durability is excellent.
For example, JIS L0844 is used as the washing condition, and the specific resistance of the stretchable conductor sheet after washing and the initial specific resistance of the stretchable conductor sheet are calculated as the washing durability, and the ratio (of the stretchable conductor sheet after washing) is calculated. Specific resistance / specific resistance of the initial stretchable conductor sheet) can be evaluated.
That is, using a machine washer and a washing net, after 5 consecutive washings, the specific resistance of the stretchable conductor sheet after 10 shades per cycle and the stretchable conductor sheet in the initial state before washing Washing durability may be evaluated using the ratio (specific change in washing durability) with the specific resistance as an index.

  In the present invention, the specific resistance of the stretchable conductor sheet after repeating five times of continuous washing and one shade drying is preferably within 4.0 times of the initial specific resistance, more preferably within 3.5 times. More preferably, it is within 3.0 times, and even more preferably within 2.5 times. If the stretchable conductor sheet of the present invention is within such a change in specific resistance after washing, it can be said that it has sufficient washing durability.

  Hereinafter, the present invention will be described in more detail and specifically with reference to examples. The evaluation results in the examples were measured by the following methods.

<Nitrile amount>
From the composition ratio obtained by NMR analysis of the obtained flexible resin, it was converted to mass% based on the mass ratio of the monomers.

<Mooney viscosity>
The Mooney viscosity was measured using an SMV-300RT “Mooney Viscometer” manufactured by Shimadzu Corporation.

<Amount of alkali metal>
The resin was incinerated, and the resulting ash was extracted with hydrochloric acid. The contents of sodium and potassium were determined by atomic absorption method, and the two were totaled.

<Elastic modulus>
The flexible resin was heat compression molded into a sheet shape having a thickness of 200 ± 20 μm, and then punched into a dumbbell mold defined by ISO 527-2-1A to obtain a test piece. A tensile test was performed by a method defined in ISO 527-1 to obtain an elastic modulus.

<Average particle size>
The average particle size was measured using a light scattering type particle size distribution measuring device LB-500 manufactured by Horiba.

<Composition analysis of inorganic particles>
The composition analysis of inorganic particles was performed using a fluorescent X-ray analyzer (fluorescent X-ray analyzer system 3270, manufactured by Rigaku Denki Co., Ltd.), and the amounts of Al component and Si component were measured. The deposition amount of the Al component and the Si component is expressed by converting the detected Al component and the metal compound of the Si component into oxides (that is, the Al component is converted into Al2O3 and the Si component is converted into SiO2).

[Evaluation of resistivity]
The stretchable conductor sheet was cut into a width of 10 mm and a length of 140 mm to prepare a test piece. The sheet resistance and film thickness of the stretchable conductor sheet test piece in the natural state (elongation rate 0%) were measured, and the specific resistance was calculated. The film thickness was measured for four test pieces using a thickness gauge SMD-565L (manufactured by TECLOCK) and the sheet resistance was Loresta-GP MCP-T610 (manufactured by Mitsubishi Chemical Analytech), and the average value was used. . The specific resistance was calculated by the following formula.
Specific resistance (Ω · cm) = Rs (Ω □) × t (cm)
Here, Rs represents the sheet resistance measured under each condition, and t represents the film thickness measured under each condition.

In the same manner as in the natural state (elongation rate 0%), using a universal testing machine (manufactured by Shimadzu Corp., Autograph AG-IS), the specific resistance was measured when it was extended to 40% (elongation speed 60 mm / min). . The elongation rate was calculated by the following formula.
In addition, the extension evaluation of the conductive film has two extension directions, one in which the direction in which the conductive paste is applied is the extension direction of the test piece, and one in which the direction orthogonal to the application direction is the extension direction of the test piece. It carried out in.
Elongation rate (%) = (ΔL0 / L0) × 100
Here, L0 represents the distance between the marked lines of the test piece, and ΔL0 represents the increment of the distance between the marked lines of the test piece. In addition, the sheet resistance at the time of extension was read as a value 30 seconds after reaching a predetermined degree of extension. Moreover, the specific resistance increase rate at 100% elongation was calculated by the following formula.
Specific resistance increase rate (%) = (R100 / R0) × 100
Here, R100 represents the specific resistance after 100% elongation, and R0 represents the specific resistance in the natural state.

[Isotropic evaluation]
A sample piece was prepared by cutting the stretchable conductor sheet forming paste into a width of 20 mm and a length of 50 mm in the direction perpendicular to the direction of application. Using each test piece, the specific resistance at an elongation rate of 40% was measured. Isotropic evaluation was made by comparing the rate of change in specific resistance between the coating direction and the test piece perpendicular to the coating direction.
Isotropic [%] = {(specific resistance in the coating direction / specific resistance in the direction perpendicular to the coating direction) -1} × 100

<Evaluation of torsion>
The specific resistance of the stretchable conductor sheet in the initial state and the specific resistance of the stretchable conductor sheet obtained by repeating the twist cycle of the twist test 100 times were calculated, and the change in specific resistance was calculated by the following formula.
Change in specific resistance (times) = specific resistance of stretchable conductor sheet with 100 twist cycles /
Specific resistance of stretchable conductor sheet in the initial state
[Torsion test:
Sample: width 10 mm, test length 100 mm (One end in the longitudinal direction of the sample is fixed and twisted by rotating one end)
Twist cycle: Twist in the positive direction (3600 °), return to the initial state,
Twist in the negative direction (-3600 °) to return to the initial state]

[Evaluation of compression resistance]
Sample: A paste for forming a stretchable conductor sheet was squeegee-coated on a release PET film and dried and cured under predetermined conditions to obtain a stretchable conductor sheet having a thickness of 100 μm. The obtained sheet was punched into a circle with a diameter of 50 mm, and 10 sheets were stacked, which was used as a sample. The specific resistance of 10 samples was measured at the center of each test piece, and the average value was obtained. This was designated as ρi.
Next, the following compression operation was performed. Using a universal testing machine (manufactured by Shimadzu Corporation), the lower side is a fixed platen, a sample is placed on the platen, and a metal cylinder with a diameter of 20 mm and a height of 10 mm with a flat bottom surface is placed on top. A cycle of releasing and compressing 10% in the thickness direction and releasing it was repeated 100 times (1 cycle / second). The specific resistance at the center of each sheet (10 sheets) of the sample after the compression operation was measured, and the average value was obtained. This was designated as ρe.
Specific resistance change (times) = ρe / ρi

[Porosity]
The porosity of the stretchable conductor sheet was calculated from the apparent specific gravity and the calculated specific gravity obtained from the preparation ratio. In this example, the calculated specific gravity was calculated with a carbon specific gravity of 2.2, a resin specific gravity of 1.25, and a specific gravity of inorganic particles of 4.5.

[Washing durability]
Washing conditions were performed in accordance with JIS L0844. Specifically, using a machine washing machine, a washing net, and a detergent (attack made by Kao Co., Ltd.), after 5 consecutive washings, 1 shade drying was repeated 10 times. The specific resistance of the stretchable conductor sheet after washing was measured, and the change from the initial specific resistance (specific resistance after washing / initial specific resistance) was determined.

[Sweat durability]
Test using a test piece prepared by the same method as the film resistance measurement, 50% stretching was repeated 100 times, and then the test piece was immersed in artificial sweat specified in JIS L 0848: 2004 for 1 hour and pulled up The piece was left in an environment of 30 ° C. and 80% RH for 48 hours, and the change in appearance after the test (mainly discoloration of silver: presence or absence of darkening) and the rate of increase in the resistance value after the test with respect to the initial resistance value were determined.

[Quantification of organic sulfur components]
The dried cured product of the paste was analyzed with a fluorescent X-ray analyzer to determine the total sulfur component, and the sulfur equivalent value of the organic sulfur component was obtained. In the chart expression of the present invention, unless otherwise specified, “sulfur component” is a sulfur conversion value of the organic sulfur component.

[Production Example 1]
<Polymerization of synthetic rubber material>
In a reaction vessel made of stainless steel equipped with a stirrer and a water cooling jacket 61 parts by mass of butadiene 39 parts by mass of acrylonitrile 270 parts by mass of deionized water sodium dodecylbenzenesulfonate 0.5 part by mass sodium naphthalenesulfonate condensate 2.5 parts by mass t -Dodecyl mercaptan 0.3 mass part Triethanolamine 0.2 mass part Sodium carbonate 0.1 mass part was prepared, the bath temperature was maintained at 15 degreeC, flowing nitrogen, and it stirred gently. Next, an aqueous solution in which 0.3 parts by mass of potassium persulfate was dissolved in 19.7 parts by mass of deionized water was dropped over 30 minutes, and the reaction was further continued for 20 hours. An aqueous solution dissolved in 5 parts by mass was added to perform a polymerization termination operation.
Next, in order to distill off the unreacted monomer, first, the inside of the reaction vessel was depressurized, and further steam was introduced to recover the unreacted monomer to obtain a synthetic rubber latex (L1) composed of NBR.
Salt and dilute sulfuric acid are added to the resulting latex for aggregation and filtration, and the resin is redispersed in deionized water in a volume of 20 times the volume ratio of deionized water, and washed by repeating filtration. And dried in air to obtain a synthetic rubber resin R01. The synthetic rubber resin R01 had a nitrile content of 39% by mass, a Mooney viscosity of 51, and an elastic modulus of 42 MPa.

[Production Example 2]
A synthetic rubber resin R02 was obtained in the same manner as in Production Example 1 except that 40 parts by mass of styrene and 60 parts by mass of butadiene were used instead of acrylonitrile and butadiene. The synthetic rubber resin R02 had a nitrile content of 0% by mass, a Mooney viscosity of 67, and an elastic modulus of 51 MPa.

[Production Example 3]
(Example of polyurethane resin production)
Synthesis of polyurethane resin composition (A) 100 parts of ODX-2044 (DIC polyester diol) and 33 parts of 6-hexanediol (manufactured by Ube Industries) as ethylene glycol monoethyl in a 1 L four-necked flask It was put in 100 parts of ether acetate and set in a mantle heater. A stir bar with a stirring seal, a reflux condenser, a temperature detector, and a ball stopper were set in the flask and dissolved by stirring at 50 ° C. for 30 minutes. 58 parts of T-100 (manufactured by Tosoh, isocyanate) and 0.1 part of dibutyltin dilaurate as a catalyst were added. When the temperature rise due to the reaction heat settled, the temperature was raised to 90 ° C. and reacted for 4 hours to obtain a polyurethane resin composition (A). The obtained resin had a reduced viscosity of 0.81, a glass transition temperature of −20 ° C., a urethane group concentration of 3495 eq / t, and the physical properties of the coating film were an elastic modulus of 55 MPa and an elongation of 1180%.
[Production Example 4]
In a stainless steel reaction vessel equipped with a stirrer and a water cooling jacket, butadiene 76 parts by mass acrylonitrile 24 parts by mass deionized water 270 parts by mass Nippon Emulsifier Co., Ltd. Antox EHD-PNA
(Polyoxyalkylene alkyl ether phosphate ester) 1.0 part by mass Nippon Emulsifier Co., Ltd. Disol AQ-3
(Polyacrylic acid sodium salt) 2.0 parts by weight Potassium hypophosphite 0.3 part by weight Triethanolamine 0.2 part by weight Sodium carbonate 0.1 part by weight was added, and the bath temperature was adjusted to 15 ° C. while flowing nitrogen. Keep and gently agitate. Next, an aqueous solution in which 0.3 parts by mass of potassium persulfate was dissolved in 19.7 parts by mass of deionized water was dropped over 30 minutes, and the reaction was further continued for 20 hours. An aqueous solution dissolved in 5 parts by mass was added to perform a polymerization termination operation.
Next, in order to distill off the unreacted monomer, first, the inside of the reaction vessel was decompressed, and further steam was introduced to recover the unreacted monomer, thereby obtaining a synthetic rubber latex (L3) composed of NBR.
Salt and dilute sulfuric acid are added to the resulting latex for aggregation and filtration, and the resin is redispersed in deionized water in a volume of 20 times the volume ratio of deionized water, and washed by repeating filtration. And dried in the air to obtain a synthetic rubber resin R07. The synthetic rubber resin R07 had a nitrile content of 24% by mass, a Mooney viscosity of 45, and an elastic modulus of 21 MPa. Moreover, the organic sulfur component was 20 ppm or less.

[Preparation of barium sulfate particles]
A Werman pump having a suction port diameter of 40 mm, a discharge port diameter of 25 mm, an internal volume of 850 mL, and an impeller rotational speed of 2380 rpm is used as a reaction tank, and a 700 L sulfuric acid aqueous solution having a concentration of 110 g / L (1.1 mol / L) and a temperature of 30 ° C. is used. Water slurry prepared at a constant flow rate of 120 g / L, and 120 g / L (0.71 mol / L) and a barium sulfide aqueous solution at a temperature of 50 ° C. at a constant flow rate of 600 L / h (solid content 95 g) / L) 1000 mL was heated to 60 ° C. 4.0 g of sodium silicate equivalent to SiO2 as diluted with 100 mL of pure water was added dropwise in 20 minutes, and 2.0 g of sodium aluminate equivalent as Al2O3 was diluted with 100 mL of pure water and added dropwise over 20 minutes. did. The reaction system was further heated to 70 ° C., stirred for 30 minutes, and neutralized to pH 8 using diluted sulfuric acid over 30 minutes. After stirring for 10 minutes, it was filtered, washed thoroughly with water and dried to obtain dry chips, coarsely crushed, and then pulverized with an airflow pulverizer. The obtained powder was applied as 3.5% by mass as SiO2 and 1.7% by mass as Al2O3 with respect to the total mass of ultrafine barium sulfate and adherend as a base material. The measured average particle size was 0.3 μm.

[Example of manufacturing conductive paste]
Using the materials shown in Table 1, conductive pastes were produced according to the mixing ratios shown in Table 2. First, the resin component is dissolved in half the amount of the solvent, and the remaining amount of the conductive particles, non-conductive particles and solvent is added to the obtained resin solution, mixed uniformly, and then dispersed in a three-roll mill, followed by defoaming operation. A conductive paste was formed without any application. The results are shown in Table 2 for the composition of the conductive paste and the single characteristics of the film obtained from each conductive paste.

[Manufacture of stretchable conductor sheet 1 (single layer)]
The first stretchable conductor paste (carbon paste) is applied to a 75 μm-thick release PET film using an applicator so that the dry film thickness becomes the thickness shown in Table 3, and then dried, cured, and stretched. Conductive sheet (single layer) was obtained. Table 3 shows the properties of the obtained stretchable conductor sheet.

[Manufacture of stretchable conductor sheet 2 (multilayer)]
Apply the first stretchable conductor paste (carbon paste) to a 75 μm thick release PET film using an applicator so that the dry film thickness is as shown in Table 3, and then dry and cure, Next, the second stretchable conductor paste (silver paste) was applied in the same manner and then dried and cured to obtain a stretchable conductor sheet composed of multiple layers.
In the roll laminating machine where NTW Co., Ltd. polyurethane hot melt film Ecelan SHM104-PUR (with separate sheet) is stacked on the second elastic conductor paste surface of the obtained elastic conductor, and the rubber roll temperature is adjusted to 120 ° C. Bonded to obtain a stretchable conductor sheet having adhesiveness.
[Die-cutting and bonding to fabric]
The obtained stretchable conductive sheet having adhesiveness was set in a die cutting machine, and a rectangle having a width of 10 mm and a length of 80 mm was punched out with a Thomson blade from the side of the separate sheet surface of the hot melt film. The depth of the Thomson blade is limited to the hot melt sheet, the second stretchable conductor layer, and the first stretchable conductor layer, and the release PET film is left without being punched.
Next, a part other than the rectangle having a width of 10 mm and a length of 80 mm is peeled and removed from the sheet after die cutting, and the separate sheet remaining in the rectangle part is peeled off. Way tricot fabric KNZ2740 is stacked so that the stretchable conductor sheet is placed in the center, and is pressed and bonded for 25 seconds at 105 ° C. and 0.03 MPa pressure with a press machine, and then the release PET film is attached. The elastic conductor sheet which peeled and was adhere | attached on the tricot fabric was obtained. The evaluation results of the obtained stretchable conductor sheet are shown in Table 4-1, Table 4-2, and Table 4-3.

[Application Example 4-1]
First, a stretchable insulating resin ink made of a urethane material serving as a cover coat layer was printed in a predetermined pattern on a release PET film having a thickness of 125 μm, and then dried and cured. The pattern corresponds to a land portion that covers the periphery of the electrode portion in a ring shape and an insulating coat portion that covers an electric wiring portion made of a stretchable conductor. The land portion covers the outer periphery 3 mm of the electrode pattern, which will be described later, and the width of the ring is 5 mm. The insulating coat part has a width of 16 mm and covers a stretchable conductor having a width of 10 mm. The dry thickness of the cover coat layer was adjusted to 20 μm.

Next, carbon paste (CG) was printed on the portion to be an electrode portion and dried and cured. The electrode part is a circle having a diameter of 50 mm arranged concentrically with the ring of the cover coat layer printed earlier. The dry film thickness of the stretchable carbon paste layer was 15 μm.
Subsequently, the electrode part and the electrical wiring part were printed using silver paste (AD). The electrode portion has a donut shape with a diameter of 50 mm, and is arranged concentrically with the ring-shaped land portion. The electric wiring part has a width of 10 mm. The thickness of the stretchable conductor portion was repeatedly printed and dried, and the dry thickness was 50 μm.

  Further, the stretchable insulating resin ink used for the cover coat layer is printed so as to overlap all the printed patterns including the cover coat layer, and the solvent is intentionally left, so that tackiness remains, 60 ° C. for 10 minutes. The transfer operation was performed to obtain a transferable printed electrode wiring sheet. Next, the transferable printed electrode wiring obtained by the above steps is superimposed on a predetermined portion of the sports shirt turned upside down, and hot pressed to transfer the printed material from the release PET film to the sports shirt, and further at 115 ° C. for 30 minutes. Dried and obtained a sports shirt with electrical wiring.

The obtained sports shirt with electrical wiring has a circular electrode with a diameter of 50 mm at the intersection of the left and right posterior axilla lines and the seventh rib, and further an electrical wiring with a stretchable conductor composition with a width of 10 mm from the circular electrode to the center of the chest Is formed inside. The wiring extending from the left and right electrodes to the center of the chest has a gap of 5 mm at the center of the back of the neck, and both are not short-circuited.

Next, a stainless steel hook is attached to the front side of the sports shirt at the center of the back of the neck without the cover coat layer on the left and right wiring parts, and a thin metal wire is twisted to ensure electrical continuity with the wiring parts on the back side. The elastic conductor composition layer and the stainless steel hook were electrically connected using a conductive thread.
Connect the heart rate sensor WHS-2 made by Union Tool through a stainless steel hook, and receive the heart rate data with an Apple smartphone that incorporates the app “myBeat” dedicated to the heart rate sensor WHS-2. Set to display. A sports shirt incorporating a heart rate measurement function was produced as described above.

  The subject was put on this shirt, and electrocardiographic data were obtained for resting, walking, running, cycling, driving, and sleeping. The obtained electrocardiogram data has low noise, high resolution, and quality that can analyze the mental state, physical condition, fatigue, drowsiness, tension, etc. of the electrocardiogram from changes in heartbeat interval, electrocardiogram waveform, etc. It was.

  As described above, by using the stretchable conductor sheet forming paste according to the present invention, it is possible to form an electrical wiring directly or indirectly on a textile or fabric product such as a stretchable textile or fabric using a printing method. . The electrical wiring on the fiber product obtained by the paste for forming the stretchable conductor sheet of the present invention is not limited to the application examples shown in the application examples, but information on the human body, that is, biopotentials such as myoelectric potential and cardiac potential. Wearable device for detecting biological information such as body temperature, pulse, blood pressure etc. on a sensor provided on clothes, or a wearable device incorporating a sensor for measuring clothes pressure, clothing incorporating an electric heating device , Clothing that uses body pressure to measure body size, sock-type devices to measure the pressure on the soles, clothing with flexible solar cell modules integrated in textiles, wiring parts such as tents and bags, joints It can be applied to wiring parts such as low-frequency treatment devices and thermal treatment devices, and sensing units for bending degree. Such wearable devices can be applied not only to the human body but also to animals such as pets and livestock, or mechanical devices having a telescopic part, a bent part, etc. It can also be used as electrical wiring for systems that are connected. It is also useful as a wiring material for implant devices that are embedded in the body.

1: Fabric 2: Support 3: Paste for forming a stretchable conductor sheet (stretchable conductor sheet)
4: Stretchable cover 5: Stretchable carbon 6: Release support 7: Adhesive

Claims (13)

  A stretchable conductor sheet comprising carbon-based conductive particles and a stretchable conductor composition having at least a flexible resin having a tensile modulus of 1 MPa to 1000 MPa, wherein the stretchable conductor sheet has a porosity of 3% by volume to 50%. A stretchable conductor sheet characterized by a volume% or less.   At least carbon conductive particles, inorganic particles having an aspect ratio of less than 1.5, an average particle diameter of 0.5 times or less of the aggregated silver particles, and a flexible resin having a tensile modulus of 1 MPa to 1000 MPa. A stretchable conductor sheet having a thickness of 3 to 800 μm, wherein the specific resistance after repeating 10% compression 100 times is within 2.4 times the initial specific resistance. . The stretchable conductor sheet according to claim 1 or 2, wherein the inorganic particles are surface-treated with one or both of Al and Si hydroxides and / or oxides. The elastic conductor sheet according to any one of claims 1 to 3, wherein a blending amount of the inorganic particles is 0.3 to 5.0 mass% with respect to a total mass of the elastic conductor sheet. It is a paste for stretchable conductor composition formation used in order to manufacture the stretchable conductor sheet in any one of Claims 1-4, Comprising: At least carbon type electroconductive particle and aspect ratio are less than 1.5 And an inorganic particle having an average particle diameter of 1 μm or less, a flexible resin having a tensile elastic modulus of 1 MPa or more and 1000 MPa or less, and a solvent, and the compounding amount of the inorganic particles includes the carbon-based conductive particles and the inorganic particles. The paste for stretchable conductor sheet formation characterized by being 2.0-30 mass% in a total of 100 mass%.   5. The change rate of the specific resistance at the time of extension in the extension direction when 40% of the original length is extended in both directions orthogonal to each other is less than ± 10%. The stretchable conductor sheet according to any one of the above. The specific resistance of the sheet after repeating the twist cycle of the following twist test 100 times is within 3.0 times of the initial specific resistance. The stretchable conductor sheet according to 1.
[Torsion test: Sample: width 10 mm, length 100 mm (fixed at one end in the longitudinal direction of the sample, twisted by rotation of the other end) Twisting cycle: twisted 10 times in the positive direction (3600 °), returning to the initial state, negative direction 10 rotations (-3600 °) twist, return to initial state]   The stretchability according to any one of claims 1 to 4, 6, and 7, wherein the flexible resin is a stretchable polymer binder that does not substantially contain an organic sulfur compound. Conductor sheet.   The flexible resin is a stretchable polymer binder that does not substantially contain an organic sulfur compound, and the content of the organic sulfur compound in the component excluding the solvent is 500 ppm or less in terms of sulfur. The paste for forming a stretchable conductor composition according to claim 5, wherein   The stretchable conductor sheet according to any one of claims 1 to 4, and 6 to 8, wherein the stretchable conductor sheet is used close to a material containing silver.   The stretchable polymer binder substantially free of organic sulfur compound is a monomer containing at least butadiene in the presence of a surfactant containing no sulfur element and a chain transfer agent containing no sulfur element. The paste for forming a stretchable conductor composition according to claim 5 or 9, wherein the paste is an aqueous polymer.   The stretchable polymer binder substantially free of organic sulfur compound is a monomer containing at least butadiene in the presence of a surfactant containing no sulfur element and a chain transfer agent containing no sulfur element. The stretchable conductor sheet according to claim 1, wherein the stretchable conductor sheet is an aqueous polymer.   A probe for measuring biological information, characterized in that the stretchable conductor sheet according to claim 12 is used in a part that contacts the skin or mucous membrane of a living body.