WO2018074402A1 - Elastic conductive sheet, elastic wiring, elastic wiring-equipped fabric, and method for restoring conductivity - Google Patents

Abstract

[Problem] To provide an elastic conductive material for forming elastic wiring in a garment-type electronic device, wherein the product life thereof which is limited by deterioration of the electrical wiring can be extended on the user side. [Solution] An electrode, electrical wiring, or the like is formed in a garment by using an elastic conductive sheet as the wiring, said elastic conductive sheet being configured from a conductive filler and a binder resin, characterized in that the unevenness in the film thickness of the sheet is 10% or less and the elastic recovery thereof after 20% elongation at 25°C is 92% or greater, and preferably, further characterized in that Mw/Mn>4 or higher, given that the number average molecular weight of the binder resin is Mn and the weight average molecular weight thereof is Mw. Furthermore, when the conductivity of this electrode or wiring decreases due to repeated stretching or laundering, it is possible to restore the conductivity thereof to a useful level by heating to 60°C or higher.

Description

Stretchable conductor sheet, stretchable wiring, fabric with stretchable wiring, and conductivity recovery method

The present invention relates to a conductive material used in a clothes-type wearable electronic device that is used by incorporating an electronic function or an electric function into a garment, and more specifically, an electric wiring having elasticity is formed, and more natural wearing The present invention relates to a clothing-type electronic device.

Recently, wearable electronic devices intended to use electronic devices having input / output, arithmetic and communication functions in close proximity to or close to the body have been developed. 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. An example of such a textile integrated device is disclosed in Patent Document 1.

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, it is obvious that this method is not suitable for mass production.
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 corrugated wiring is formed by a technique similar to that of a printed wiring board to make a pseudo stretchable wiring. (Refer to Non-Patent Document 1) Such a technique is to give a pseudo expansion / contraction characteristic by torsional deformation of the corrugated wiring portion. However, since the metal foil is also deformed in the thickness direction by torsional deformation, When used, it was very uncomfortable and unpleasant. 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.

As a technique for realizing a stretchable conductor wiring, a method using a special conductive paste has been proposed. Conductive particles such as silver particles, carbon particles, carbon nanotubes and elastomers such as stretchable urethane resin, natural rubber, synthetic rubber, solvent, etc. are kneaded to form a paste, directly on clothes or stretchable film base The wiring is printed and drawn in combination with a material.
Macroscopically, a conductive composition composed of conductive particles and a stretchable binder resin can realize a stretchable conductor. When viewed microscopically, the conductive composition obtained from such a paste maintains its conductivity within a range in which the resin binder portion is deformed when external force is applied and the electrical chain of the conductive particles is not interrupted. It is. The specific resistance observed macroscopically is higher than that of metal wires and metal foils, but because the composition itself has elasticity, there is no need to adopt a shape such as corrugated wiring, and the wiring width and thickness. Since there is a high degree of freedom, it is practically possible to realize a low resistance wiring compared to a metal wire.

Patent Document 2 discloses a technique for suppressing a decrease in conductivity at the time of elongation by combining silver particles and silicone rubber and further coating a conductive film on a silicone rubber substrate with silicone rubber. Patent Document 3 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. Further, many examples have been proposed in which characteristics are improved by combining high aspect ratio conductive particles such as carbon nanotubes and silver fillers.

Patent Document 4 discloses a technique for directly forming electrical wiring on clothes using a printing method.

JP-A-2-234901 JP 2007-173226 A JP 2012-54192 A Japanese Patent No. 3723565

The stretchable conductor composition is mainly composed of conductive particles and a flexible resin. As such a stretchable conductor, a composition in which a crosslinked elastomer such as rubber is used as a resin binder and carbon black or metal particles is blended is generally known. Such a stretchable conductor composition is formed through a paste or slurry obtained by mixing, dissolving, and dispersing a solvent or the like into the metal-based conductive particles and the precursor of the cross-linked elastomer as necessary. When the paste is used, it becomes easy to form a wiring pattern by screen printing or the like.

When wiring is formed on a fabric constituting a garment using a stretchable conductive composition obtained from a stretchable conductive paste using a stretchable binder, a similar technique, for example, a conductive paste is used. There are various differences compared to the conventional membrane circuit formation technology, which leads to technical difficulties.
Usually, in a membrane circuit using engineering plastic film such as PET film as a base material, the entire circuit has flexibility, but the elasticity itself with respect to the tensile load of the base material itself is so high that it exhibits substantially stretchability. Absent. On the other hand, when a wiring made of a stretchable conductor composition is formed using a fabric or a flexible polymer sheet as a base material, a stretchable wiring can be realized. Appropriately designed and manufactured, such stretchable conductor wiring can maintain electrical conductivity even when stretched from about 10% to a maximum of 100% or more.

However, the stretchable conductive film composed of the conductive particles and the stretchable binder resin is a dispersion system, and the elastic range, that is, the range in which the tensile load and the strain (elongation) are linearly proportional, is narrow, It is only a few percent at most. When the deformation is applied beyond the elastic range, minute cracks are generated inside the coating, and the coating is continuously deformed by widening the gap generated by the crack. In this state, since the coating around the crack is still flexible, the coating does not completely break, and microscopic internal structural changes such as an increase in the number and width of cracks are macroscopically fatal. This is an area that seems to continue to stretch flexibly without breaking. In this region, the film does not break, but in terms of internal structure, the conductive path gradually narrows due to the chain of conductive particles due to the growth of microcracks, and as a result, the conductivity of the film decreases.

The stretchable conductive film stretched to the plastic deformation region contracts to return to a length close to the initial length when the tensile load is removed, but the resistance is set to the initial value because the connection of the conductive particles is broken. It does not return until it becomes a value higher than the initial value. As described above, when the stretching beyond the elastic region is repeated, the resistance value of the stretchable conductive film gradually increases and finally reaches non-conduction. As described above, the conventional stretchable conductive film has a problem that the conductivity decreases due to repeated stretching, and when such a stretchable dynamic coating is used for wiring of a clothes-type electronic device, repeated stretching that occurs in actual use is used. Furthermore, the durability against repeated expansion and contraction has been a problem due to the water flow applied during washing.

As a result of intensive studies to achieve this object, the present inventor has found that repeated stretch durability is practically greatly improved by imparting specific characteristics to the stretchable conductive film, and the following invention is achieved. Reached.
That is, the present invention has the following configuration.
[1] In a stretchable conductor sheet composed of a conductive filler and a binder resin, the film thickness unevenness of the sheet is 10% or less, and the stretch recovery rate after stretching 20% at 25 ° C. is 92% or more. A stretchable conductor sheet characterized by that.
[2] The stretchable conductor sheet according to [1], wherein after 20% stretching at 25 ° C, the stretch recovery rate is 96% or more when heated at 60 ° C with the stretching load removed.
[3] The initial electrical conductivity in the sheet surface direction of the stretchable conductor sheet is 1 × 10 ² S / cm or more, and the electrical conductivity reduction ratio due to a mechanical load is within a range of 1/1000 of the initial electrical conductivity. The stretchable conductor sheet according to [1] or [2], wherein the conductivity recovery rate by heating at 60 ° C. is 10% or more.
[4] A conductive filler consisting of 65 to 85% by weight of a binder resin having a stretch recovery rate of 20% or higher after stretching by 20% and a glass transition temperature of 0 ° C. or lower and 90% by weight or more of metal particles. % Of the stretchable conductor sheet according to any one of [1] to [3].
[5] When the number average molecular weight of the binder resin is Mn and the weight average molecular weight is Mw,
The elastic conductor sheet according to any one of [1] to [4], wherein Mw / Mn> 4 or more.
[6] An insulating fabric layer having an elongation recovery rate of 99% or more at 50% elongation and heat resistance of 60 ° C. or more, and the stretchable conductor sheet according to any one of [1] to [5] Stretchable conductor / fabric laminate having a layer.
[7] The stretchable conductor sheet according to any one of [1] to [5], or the heating according to [6], wherein the stretchable conductor sheet is heated to 60 ° C. or more in a state in which an extension load is removed. Method for recovering electrical conductivity of stretchable conductor / fabric laminate.

Furthermore, this invention has the following structures.
[8] At least
A stretchable insulating polymer layer having a tensile yield elongation of 70% or more and a thermal deformation temperature of 60 ° C or more;
Stretchable conductor layer composed of conductive filler and binder resin,
Elastic wiring composed of
[9] The stretchable wiring according to [8], wherein the stretchable conductor layer has a stretch recovery rate of 92% or more after 20% stretch at 25 ° C.
[10] The initial conductivity in the plane direction of the stretchable conductor layer is 1 × 10 ² S / cm or more,
When the electrical conductivity reduction ratio due to mechanical load is in the range of 1/1000 or more of the initial electrical conductivity,
The stretchable wiring according to [8] or [9], wherein a conductivity recovery rate by heating at 60 ° C. is 10% or more.
[11] The stretchable conductor layer has a stretch recovery rate after stretching by 20% of 99% or more, a binder resin of 65 to 85% by mass with a glass transition temperature of 0 ° C. or less, and metal particles from 90% by mass or more. The stretchable wiring according to any one of [8] to [10], comprising 15 to 35% by mass of a conductive filler.
[12] When the number average molecular weight of the binder resin is Mn and the weight average molecular weight is Mw,
The stretchable wiring according to any one of [8] to [11], wherein Mw / Mn> 4 or more.
[13] The stretchable wiring according to any one of [8] to [12] is provided on an insulating fabric having a stretch recovery rate of 99% or higher at 50% stretch and having heat resistance of 60 ° C or higher. A fabric with a stretchable wiring characterized by the above.
[14] The method for recovering the conductive property of the elastic wiring according to any one of [8] to [12], wherein the elastic wiring is heated to 60 ° C. or higher in a state where the tensile load of the elastic wiring is removed.
[15] The method for recovering electrical conductivity of a fabric with stretchable wiring according to [13], wherein the fabric with stretchable wiring is heated to 60 ° C. or higher in a state where an extension load is removed.

The stretchable conductor sheet and stretchable conductor layer of the present invention have a dispersed structure composed of conductive particles and a stretchable binder resin. As described above, when the flexible film having such a dispersion structure is stretched, it has an elastic deformation region in which the hook law is established according to the degree of stretching, and a plastic deformation region that deviates from the hook law. As described above, the elastic region is narrow and microcracks are generated inside the coating in the composition region. The composition region observed here is a plastic region observed from a macroscopic viewpoint. An irreversible structural change occurs due to the occurrence of minute cracks in the coating, but the binder resin portion where no cracks are generated is elastically deformed.
Hereinafter, unless otherwise specified, the stretchable conductor sheet has the same meaning as the stretchable conductor layer, and is composed of the same stretchable conductor composition. The stretchable laminate and the stretchable conductor layer in the stretchable wiring have a predetermined size. It is a processed elastic conductor sheet.

In the present invention, the main purpose is to suppress a decrease in practical conductive performance by adjusting the stretch recovery rate of the stretchable conductor sheet macroscopically to be 92% or more. That is, even when the conductive path due to particle contact is cut off due to micro cracks generated when the stretchable conductor sheet is stretched, if the stretchable conductor sheet itself has a sufficiently high stretch recovery rate, it is once cut off. The contact between the conductive particles is reproduced, and the resistivity is reduced, that is, the conductivity is restored. The stretch recovery of the stretchable conductor sheet is mainly due to the flexibility of the binder resin, and this effect is enhanced by using a binder resin that has a high recovery rate and at the same time exhibits a strong shrinkage force. When a polymer is stretched by a tensile load, the polymer chain that was originally in a crimped state has a shape in which the chain is stretched. In such a state, when an operation for increasing the degree of freedom of the polymer chain, that is, a plasticizing operation with heating or a solvent is performed, the stretched polymer chain expresses a contraction force to return to the original crimped state. . As in the present invention, the binder resin exhibiting a predetermined stretch recovery rate as the stretchable conductor sheet also has such an effect, and therefore, the stretch load was removed from the stretchable conductor sheet whose conductivity was reduced by repeated use such as stretching. By heating to an appropriate temperature in the state, the stretch recovery rate can be further increased, and the contact state between the conductive particles that has been cut off is also recovered.

In the present invention, the recovery effect can be further enhanced by widening the molecular weight distribution of the binder resin. In other words, the relatively high molecular weight resin component controls the stretchability, and at the same time, the relatively low molecular weight component self-repairs and fills microcracks, thereby restoring the mechanical dimensions as well as the conductive performance. Promoted. Such an effect can be further promoted by heating to an appropriate temperature in a state where the extension load is removed.

It is the schematic for demonstrating the tensile yield elongation in this invention. It is the schematic for demonstrating the expansion | restoration recovery rate in this invention. It is the schematic which shows the manufacturing process of the wear with wiring by the direct printing method in this invention. It is the schematic which shows the manufacturing process of the wear with wiring by the printing transfer method in this invention. It is the schematic which shows an example of the state which laid the wiring in the shirt. It is the schematic which shows an example of the shape of wiring.

The stretchable conductor sheet, stretchable conductor layer, and stretchable wiring in the present invention include at least a stretchable insulating polymer layer having a tensile yield elongation of 70% or more and a thermal deformation temperature of 60 ° C or more, It is comprised from the elastic conductor layer comprised from a conductive filler and binder resin.

1
In the present invention, the tensile yield elongation is a curve (S−) obtained by a general tensile test, where the vertical axis is weight (or strength) and the horizontal axis is strain (or elongation or elongation). In the S curve), the elongation at the first point at which an increase in elongation is observed without an increase in weight, that is, the yield point. In general, the yield point is generally regarded as a point indicating the boundary of transition from elastic deformation to plastic deformation.
FIG. 1A is a schematic diagram showing a typical SS curve obtained in a tensile test, in which SR: tensile strength at break SB: tensile strength SS: tensile yield strength ER: tensile elongation at break EB: tensile Elongation ES: Tensile yield elongation.
The tensile yield elongation of the stretchable insulating polymer layer in the present invention is preferably 80% or more, more preferably 95% or more, and still more preferably 120% or more.
The upper limit of the tensile yield elongation is 450%, preferably 360%. If the tensile yield strength is higher than necessary, the mechanical strength as the insulating protective layer may be impaired.

The heat deformation temperature in the present invention means that the resin occupies one of fluidity, tackiness, and adhesiveness at the temperature. The thermal deformation temperature is a remarkable deformation in the stretchable insulating polymer layer or adhesion between the metal and the stretchable insulating polymer layer when the stretched insulating polymer layer adjusted to the specified temperature is brought into contact with the metal adjusted to the same specified temperature. Judgment is made based on whether or not adhesiveness or adhesiveness is produced. In the present invention, as a simple method, the iron heated to a predetermined temperature is brought into contact, and after maintaining the time for which the stretchable insulating polymer layer is sufficiently heated (1 minute), the iron is separated from the stretchable insulating polymer layer, It is possible to use a method for determining whether the elastic insulating polymer layer is deformed or not and whether it exhibits adhesiveness / adhesiveness when the iron is released or not based on the tactile sensation and whether or not the heat distortion temperature has been reached.
The heat distortion temperature of the stretchable insulating polymer layer in the present invention is essentially 60 ° C. or higher, preferably 75 ° C. or higher, more preferably 90 ° C. or higher, and further preferably 110 ° C. or higher. The upper limit of the heat distortion temperature depends on the heat resistance of the fabric, but is preferably 180 ° C. In addition, Preferably it is 160 degreeC. If the thermal deformation temperature is lower than this range, the elastic wiring may cause blocking, and if the thermal deformation temperature exceeds this range, flexibility may be hindered.

As the stretchable insulating polymer layer having a tensile yield elongation of 70% or more and a heat distortion temperature of 60 ° C. or more in the present invention, a non-crosslinked or crosslinked elastomer can be used. The non-crosslinked elastomer used in the present invention is preferably a thermoplastic elastomer resin having an elastic modulus of 1 to 1000 MPa, preferably a glass transition temperature in the range of −60 ° C. to 15 ° C., Examples include thermoplastic synthetic resins, synthetic rubbers, and natural rubbers. More specifically, 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, Examples include ethylene propylene 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 is particularly preferable.
As the crosslinked elastomer in the present invention, a crosslinked rubber obtained by blending a crosslinking agent with the above-mentioned non-crosslinked elastomer can be preferably used. As the crosslinking agent, sulfur, a sulfur-based crosslinking agent (so-called vulcanizing agent), an organic peroxide, a metal oxide, an organic amine compound, or the like can be used. In the present invention, it is preferable to use a non-sulfur crosslinking agent. In the case of sulfur or a sulfur-containing crosslinking agent, the liberated sulfur-containing component may act on the conductive particles of the conductive layer to cause inconveniences such as a decrease in conductivity.
In the cross-linked elastomer in the present invention, the cross-link density is preferably relatively low in order to keep the yield elongation within a predetermined range. In the present invention, it is preferable to keep the crosslinking density so that the gel fraction using tetrahydrofuran as a solvent is 90% by mass or less, preferably 80% by mass or less.

In the present invention, the stretchable insulating polymer layer can be bonded to the fabric or stretchable conductor layer by other adhesive means such as self-adhesion / adhesion or a hot melt adhesive layer after being formed alone.
In the present invention, the stretchable insulating polymer layer can be formed by melting and extruding a polymer material forming the stretchable insulating polymer layer on the cloth or the stretchable conductor layer.
Still further, in the stretchable insulating polymer layer of the present invention, the polymer material forming the stretchable insulating polymer layer is blended with a solvent as necessary, a crosslinking agent added as necessary, an additive and the like. It can be formed by forming an ink, printing or coating on a cloth or stretchable conductor layer, and drying and curing. About the solvent and additive which can be used, it applies to the material which can be used for the elastic conductor layer mentioned later.

In the stretchable conductor sheet and stretchable conductor layer of the present invention, the thickness unevenness of the sheet or conductor layer is 10% or less, and the stretch recovery rate after stretching 20% at 25 ° C. is 92% or more. Required.
In the present invention, the film thickness unevenness of the stretchable conductor sheet is preferably 8% or less. When the film thickness is large, the elongation of the thin film is selectively increased when an extension load is applied, so the deterioration is partially accelerated, and the overall conductivity is seen. This is because the degree of decrease increases and the mechanical damage and electrical damage of the sheet also increase. In the present invention, this effect can be more remarkably expressed by setting the film thickness unevenness of the sheet to 10% or less.

The film thickness unevenness [%] in the present invention was determined by randomly measuring the thickness of 10 points on a 10 cm square sheet and obtaining 100 × (maximum film thickness−minimum film thickness) / average film thickness (10 points average). Ask.
The film thickness unevenness of the stretchable conductor sheet of the present invention is preferably 8% or less, more preferably 6% or less, and still more preferably 4% or less.

In the present invention, the stretch recovery rate means that when the stretchable conductive sheet is suspended as shown in FIG. 1 and stretched by applying a load, and the load is removed and contracted, the initial length is L ₀ , When the length when stretched by 20% to a predetermined percentage is L ₁ and the length when the stretch load is removed is L ₂ ,
(Equation 1)
Elongation recovery rate = ((L ₁ −L ₂ ) / (L ₁ −L ₀ )) × 100 [%]
(Equation 2)
Residual strain rate = ((L ₂ −L ₀ ) / L ₀ ) × 100 [%]
L ₀ initial length L ₃ elongation = L ₁ −L ₀
L ₄ recovery length = L _1- L ₂
L ₅ residual strain = L ₂ −L ₀
And define. A similar measurement method is stipulated in the JIS L 1096 woven and knitted fabric test method, but it is not the recovery rate after stretching under a constant load, but the recovery rate when stretched to a certain length. Different. In actual use, the load applied to the stretchable conductor layer is often repeatedly stretched to a predetermined length regardless of the load, so that the practical performance cannot be expressed by the stretch recovery rate by the constant load method. Unless otherwise specified, the extension recovery rate is evaluated under an environment of 25 ° C. ± 3 ° C.

The stretchable conductor sheet, stretchable conductor layer, and stretchable wiring in the present invention have a stretch recovery rate of 96% or more when heated at 60 ° C with the stretching load removed after 20% stretch at 25 ° C. It is preferable.
Here, the state in which the extension load is removed refers to a state in which the load applied when the extension load is extended is removed, and the self-weight acting as the extension load is also removed. Ideally, it should be weightless or floated in a fluid with the same specific gravity as the stretchable conductor sheet, but if it is practically handled as if the sample is lying horizontally on a table placed horizontally, In effect, it can be treated as a state where the extension load is removed.

As means for heating to 60 ° C., direct heating with a hot plate, iron, trouser press, etc., hot air irradiation with a dryer, hot blaster, etc., vapor irradiation, strong light irradiation, infrared heating, radiant heating from a heater, etc. Can be used. Also, immersion in warm water is an effective method.
The extension recovery rate after heating can be determined by the same method as the extension recovery rate at 25 ° C., except that the recovery length after heating is used. The elongation recovery rate after heating is preferably 97% or more, more preferably 98% or more, and still more preferably 98.8% or more.

It is preferable that the initial conductivity in the surface direction of the stretchable conductor sheet, the stretchable conductor layer, and the stretchable wiring is 1 × 10 ⁻³ S / cm or more. The conductivity is the reciprocal of the specific resistance. The initial conductivity of the stretchable conductor sheet of the present invention is preferably 1 × 10 ⁻² S / cm or more, more preferably 1 × 10 ⁻¹ S / cm or more, and still more preferably 1 × 10 ⁰ S. / Cm or more.
The conductivity S [1 / (Ω · cm)] is the resistance value in the length L direction of the conductive film having a width W [cm], a length L [cm], and a thickness t [cm]. ]
S = (1 / R) · (L / (t · W))
Can be requested.

In the present invention, when the electrical conductivity decreasing ratio in the sheet surface direction of the stretchable conductor sheet is within 1/1000 of the initial electrical conductivity by a mechanical load test, the electrical conductivity recovery rate by heating at 60 ° C. is 10%. The above is preferable. here,
Ratio of decrease in conductivity by mechanical load test = conductivity after mechanical load test / initial conductivity,
Conductivity recovery rate after mechanical load test = conductivity after heating at 100 × 60 ° C. after mechanical load test / initial conductivity,
It is. The stretchable conductor sheet exhibiting the stretch recovery rate in the present invention regains the electrical contact between the conductive particles at the time of stretch recovery, and the contact between the conductive particles becomes more dense due to the contraction force generated by heating. Can be expressed.
The conductivity recovery rate by heating at 60 ° C. after the mechanical load test is more preferably 15% or more, further preferably 25% or more, and still more preferably 35% or more.

Furthermore, in the present invention, when the ratio of conductivity reduction in the sheet surface direction of the stretchable conductor sheet after the washing test is within a range of 1/1000 of the initial conductivity, the conductivity recovery rate by heating at 60 ° C. is 10%. The above is preferable. here,
Ratio of decrease in conductivity after washing test = conductivity after washing test / initial conductivity,
Conductivity recovery rate after washing test = conductivity after heating at 100 × 60 ° C. after washing test / initial conductivity,
It is. In the washing test, mechanical load is applied both in the stretching direction and in the compression direction in water or in water containing detergent, and more complicated deformation is applied to the conductive sheet than simple mechanical load. The stretchable conductor sheet shown can regain electrical contact between the conductive particles upon recovery from stretching, and can further exhibit such characteristics because the contact between the conductive particles becomes more dense due to the contraction force generated by heating.
The conductivity recovery rate by heating at 60 ° C. after the washing test is more preferably 15% or more, further preferably 25% or more, and still more preferably 35% or more.

The stretchable conductor sheet, stretchable conductor layer, and stretchable wiring of the present invention are composed of a conductive filler mainly composed of metal particles and a binder resin.
The conductive particle of the present invention is a particle having a specific resistance of 1 × 10 ⁻² Ωcm or less and a particle diameter of 0.5 μm or more and 5 μm or less. Examples of the substance having a specific resistance of 1 × 10 ⁻² Ωcm or less include metals, alloys, and doped semiconductors. The conductive particles preferably used in the present invention are metals such as silver, gold, platinum, palladium, copper, nickel, aluminum, zinc, lead and tin, alloy particles such as brass, bronze, white copper and solder, and silver-coated copper. Hybrid particles, metal-plated polymer particles, metal-plated glass particles, metal-coated ceramic particles, and the like can be used.

In the present invention, it is preferable to mainly use flaky silver particles or amorphous aggregated silver powder. Here, the main use is to use 90% by mass or more of the conductive particles. The amorphous aggregated powder is a three-dimensional aggregate of spherical or irregularly shaped primary particles. Amorphous agglomerated powders and flaky powders are preferable because they have a specific surface area larger than that of spherical powders and the like and can form a conductive nitrate work even with a low filling amount. Since the amorphous agglomerated powder is not in a monodispersed form, the particles are in physical contact with each other, so that it is easy to form a conductive nitrate work.

The particle diameter of the conductive particles is such that the average particle diameter (50% D) measured by the dynamic light scattering method is 0.5 to 5 μm, more preferably 0.7 to 3 μm. When the average particle diameter exceeds a predetermined range, it becomes difficult to form fine wiring, and clogging occurs in the case of screen printing. When the average particle size is less than 0.5 μm, it is impossible to make contact between particles at low filling, and the conductivity may deteriorate.

In the present invention, carbon black having a DBP oil absorption of 100 to 550 can be used as the conductive filler. There are many types of carbon black that differ in raw materials and production methods, each having its own characteristics. The DBP oil absorption is a parameter indicating the liquid absorption and retention performance of carbon black, and is measured based on ISO 4656: 2012. In the present invention, the DBP oil absorption amount is preferably 160 or more and 530 or less, more preferably 210 or more and 510 or less, and still more preferably 260 or more and 500 or less. If the DBP oil absorption amount is less than this range, the fine lines are easily filled when fine lines are printed, and the fine line printability is lowered. Also, if the DBP oil absorption exceeds this range, the viscosity of the paste tends to increase, and it is necessary to increase the amount of the solvent to adjust the viscosity, so that when the fine line is printed, the solvent tends to bleed between the lines, Similarly, fine line printability is reduced.
The compounding amount of carbon black is 0.5% by mass or more and 2.0% by mass or less, preferably 0.7% by mass or more and 1.6% by mass or less, based on the total amount of the metal filler and carbon black.

In the present invention, non-conductive particles having an average particle size of 0.3 μm or more and 10 μm or less may be included. The non-conductive particles in the present invention are mainly metal oxide particles, such as silicon oxide, titanium oxide, magnesium oxide, calcium oxide, aluminum oxide, iron oxide, metal sulfate, metal carbonate, metal A titanate or the like can be used. In the present invention, it is preferable to use barium sulfate particles among such non-conductive particles.

The binder resin used for the stretchable conductor sheet, stretchable conductor layer, and stretchable wiring of the present invention preferably has a stretch recovery rate of 20% or more after stretching by 20%, more preferably 99.5% or more. Is more preferable, and it is still more preferable that it is 99.85% or more. The elongation recovery rate of the binder resin is measured in an environment of 25 ± 3 ° C. by molding the binder resin on a sheet having a thickness of 20 to 200 μm and a film thickness unevenness of 10% or less. If the stretch recovery rate of the binder resin is less than this range, it becomes difficult to set the stretch recovery rate of the stretchable conductor sheet to a predetermined range or more.

As the binder resin in the present invention, a non-crosslinked elastomer can be used. The non-crosslinked elastomer is preferably a thermoplastic elastomer resin having an elastic modulus of 1 to 1000 MPa, and preferably a glass transition temperature in the range of −40 ° C. to 0 ° C., and a thermoplastic synthetic resin, Examples include rigid rubber and natural rubber. In order to express the stretchability of the coating film (sheet), rubber or polyester resin 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 is particularly preferable.
The elastic modulus of the flexible resin is preferably 3 to 600 MPa, more preferably 10 to 500 MPa, further preferably 15 to 300 MPa, even 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 preferable. 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% by mass in 100% by mass of nitrile-containing rubber (for example, acrylonitrile butadiene copolymer rubber). It is particularly preferable that the content is% by mass.

The glass transition temperature of polyester resin and urethane rubber is preferably -40 ° C to 0 ° C. Further, it preferably has a block copolymer structure composed of a hard segment and a soft segment. The elastic modulus of the non-crosslinked elastomer of the present invention is preferably in the range of 1 to 1000 MPa, more preferably 3 to 600 MPa, further preferably 10 to 500 MPa, and still more preferably 30 to 300 MPa. The non-crosslinked elastomer of the present invention preferably has a glass transition temperature of 0 ° C. or lower, preferably −5 ° C. or lower, more preferably −10 ° C. or lower.

The glass transition temperature of such a binder resin is preferably 0 ° C. or lower, more preferably −8 ° C. or lower, even more preferably −16 ° C. or lower, still more preferably −24 ° C. or lower. When the glass transition temperature exceeds this range, the stretch recovery property is hardly exhibited.
The stretchable conductor sheet of the present invention is preferably composed of at least 65 to 85% by mass of a binder resin and 15 to 35% by mass of a conductive filler comprising 90% by mass or more of metal particles.
The glass transition temperature can be determined by differential scanning calorimetry (DSC) according to a conventional method.

In the present invention, when the number average molecular weight of the binder resin is Mn and the weight average molecular weight is Mw, it is essential that Mw / Mn> 4 or more, and Mw / Mn> 4.4 or more. Is more preferable, Mw / Mn> 4.8 or more is more preferable, and Mw / Mn> 5.2 or more is still more preferable. Mw / Mn is a factor representing the molecular weight distribution, and the larger the Mw / Mn, the wider the molecular weight distribution. In the binder resin component having a wide molecular weight distribution, the relatively high molecular weight component dominates the stretch recovery property. On the other hand, the relatively low molecular weight component has a function of bleeding in the microcrack portion generated at the time of stretching and connecting the microcracks again in a self-repairing manner when the stretch is recovered.
The number average molecular weight and the weight average molecular weight can be determined by GPC (gel permeation chromatography) analysis according to a conventional method.

The binder resin does not need to be a single resin, and a high molecular weight resin having a high elongation recovery rate and a different low molecular resin having a high self-healing function may be used in combination. In the present invention, a binder resin having two or more peaks in a molecular weight distribution obtained by blending a resin having a peak in the weight average molecular weight of 800 to 4000 and a resin having a peak in the range of the weight average molecular weight of 4000 to 100,000. Is preferably used.

In the present invention, a non-crosslinked elastomer is used as a main binder resin, but a branching component can be added to obtain a high molecular weight binder resin. When there are a lot of branched components, the molecular structure may be almost the same as the crosslinked structure. As described above, in the present invention, a crosslinked high molecular weight elastomer and a low molecular weight non-crosslinked elastomer can be appropriately mixed and used.

The stretchable conductor sheet in the present invention is a single membrane in a sheet-like or film-like state constituted by the stretchable conductor composition.
The stretchable conductor sheet of the present invention can be formed into a sheet by a technique such as extrusion molding by directly melting and mixing a conductive filler and a binder resin. Such a method can be suitably applied when the binder resin has a relatively low melt viscosity at a relatively low temperature.
As a preferable production method in the present invention, at least a conductive filler, a binder component is added with a solvent component, mixed, stirred and kneaded to obtain a paste for forming a stretchable conductor, and the obtained paste is used for a coating method. And a method of forming a sheet.
Similarly, a paste for forming a stretchable conductor is obtained, and a sheet or an electric wiring pattern can be obtained by a method of directly patterning by the printing method using the obtained paste.
As the 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, or the like can be used. Furthermore, a method of directly drawing wiring using a dispenser or the like can be interpreted as printing in a broad sense and used.

The solvent used in the paste for forming a stretchable conductor of the present invention is preferably an organic solvent having a boiling point of 200 ° C. or higher and a saturated vapor pressure at 20 ° C. of 20 Pa or lower. If the boiling point of the organic solvent is too low, the solvent volatilizes during the paste manufacturing process or use of the paste, and there is a concern that the component ratio of the conductive 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. In addition, since the drying and curing process takes a long time, the edge sagging during the drying process increases and it becomes difficult to keep the gap between the wirings narrow.

As the organic solvent in the present invention, benzyl alcohol (vapor pressure: 3 Pa, boiling point: 205 ° C.), terpionol (vapor pressure: 3.1 Pa, boiling point: 219 ° C.), diethylene glycol (vapor pressure: 0.11 Pa, boiling point: 245 ° C.) , Diethylene glycol monoethyl ether acetate (vapor pressure: 5.6 Pa, boiling point 217 ° C.), diethylene glycol monobutyl ether acetate (vapor pressure: 5.3 Pa, boiling point: 247 ° C.), diethylene glycol dibutyl ether (vapor pressure: 0.01 mmHg or less, boiling point: 255 ° C. ), Triethylene glycol (vapor pressure: 0.11 Pa, boiling point: 276 ° C.), triethylene glycol monomethyl ether (vapor pressure: 0.1 Pa or less, boiling point: 249 ° C.), triethylene glycol monoethyl ether (vapor pressure: 0.3 Pa, Boiling point: 256 ° C.), triethylene glycol monobutyl ether (vapor pressure: 1 Pa, boiling point: 271 ° C., tetraethylene glycol (vapor pressure: 1 Pa, boiling point: 327 ° C.), tetraethylene glycol monobutyl ether (vapor pressure: 0.01 Pa or less, boiling point: 304 ° C.), tripropylene glycol (vapor pressure: 0.01) Pa or less, boiling point: 267 ° C.), tripropylene glycol monomethyl ether (vapor pressure: 3 Pa, boiling point: 243 ° C.), diethylene glycol monobutyl ether (vapor pressure: 3 Pa, boiling point: 230 ° C.) can be used.
Two or more of these solvents may be included as necessary in the present invention. Such an organic solvent is appropriately contained so that the paste for forming the stretchable conductor composition has a viscosity suitable for printing or the like.

The stretchable conductor forming paste of the present invention can be obtained by mixing and dispersing with a disperser such as a dissolver, a three-roll mill, a self-revolving mixer, an attritor, a ball mill, or a sand mill.

The paste for forming a stretchable conductor of the present invention is provided with known organic and inorganic additives such as imparting printability, color tone adjustment, leveling, antioxidants, ultraviolet absorbers and the like within the scope of the invention. Can be blended.

The paste for forming a stretchable conductor thus obtained is dried and cured to obtain an electrical wiring pattern composed of a stretchable conductor sheet or a stretchable conductor substantially free from a solvent and exhibiting a predetermined stretch recovery rate. be able to.
In the case of obtaining a stretchable conductor sheet, the paste for stretchable conductor formation can be applied to a film substrate coated with a release agent using a die coater, a slit coater, a comma coater, a gravure coater or the like and dried to form a sheet.

In the present invention, using the stretchable conductor sheet described above, an electrical wiring can be formed on an insulating fabric having a recovery rate of 99% or more at 50% elongation and heat resistance of 60 ° C. or more. . In the present invention, the heat resistance of the fabric is evaluated based on the heat shrink temperature of the material fiber.
The electrical wiring can be produced by cutting a stretchable conductor sheet into a predetermined shape and attaching it to a fabric with an adhesive or the like. It is also possible to obtain an electrical wiring pattern having a predetermined shape by a printing method after forming a base layer directly on the fabric or with an insulating resin in advance.
Furthermore, a predetermined pattern can be formed on another substrate having releasability by printing or the like, and transferred to the fabric. In the present invention, an insulating cover layer is formed on the wiring as necessary.
As the 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, or the like can be used. In the present invention, it is preferable to use a screen printing method or a stencil method. A method of directly drawing wiring using a dispenser or the like may be interpreted as printing in a broad sense.
In the present invention, clothes having an electrical wiring made of the stretchable conductor composition can be produced by these methods.

In the stretchable conductor sheet in the present invention, the cloth having the electrical wiring made of the stretchable conductor, and the clothes having the electrical wiring, for example, the iron, the trouser press, the hair in the state where the stretched load of the stretchable conductor portion is removed. By heating to 60 ° C. or higher using a dryer or the like, the conductive performance can be recovered from a state in which the conductivity is deteriorated due to a load such as repeated stretching in practical use to a state in which it can be practically used. Such a process is called a conductive recovery process. The heating temperature used for the conductive recovery treatment is preferably 75 ° C. or higher, more preferably 90 ° C. or higher, and still more preferably 110 ° C. or higher. Note that the upper limit of the temperature of the conductive recovery treatment depends on the heat resistance of the shared base material and the like. In a woven or knitted fabric made of general chemical fibers, the upper limit is about 150 ° C. Of course when using relatively high heat resistant fibers such as cotton, heat resistant fiber materials such as aramid fibers, polybenzazole fibers, polyimide fibers, and heat resistant flexible resins such as silicone resins as the base material This is not restrictive, and a range of 180 ° C. to 300 ° C. may be used with care so as not to cause excessive thermal damage to the binder resin.

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.

<Tensile yield elongation>
A resin material used for the stretchable insulating polymer layer is formed into a sheet shape with an arbitrary thickness in the range of 20 μm to 200 μm, and then punched into a dumbbell mold defined by ISO 527-2-1A. It was. Subsequently, the SS curve was obtained using a tensile tester, the yield point was obtained as shown in FIG. 1A, and the elongation at that time was defined as the tensile yield elongation.

<Heat deformation temperature>
A sheet of stretchable insulating polymer is placed on a hot plate and heated to a predetermined temperature. Next, an electric iron having an iron hot plate heated to the same predetermined temperature is placed on the stretchable insulating polymer sheet for 1 minute, and then the electric iron is lifted. When lifted together with the hot plate, it was judged that there was adhesion and adhesion. Moreover, when the trace which had been in the iron can be visually determined, it determined with having thermally deformed. The measurement was carried out by raising the predetermined temperature in increments of 60 ° C. to 5 ° C., and the lowest temperature at which any one of thermal deformation or adhesion / adhesion was observed was defined as the thermal deformation temperature. When the temperature reached 180 ° C., the test was stopped there. When the fabric was deformed or abnormal, the test was stopped at that temperature, and it was determined that the thermal deformation temperature was higher than that temperature.

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

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

<Elastic modulus>
The binder resin was molded into a sheet shape with an arbitrary thickness in the range of 20 μm to 200 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 a stress-strain diagram of the resin material, and an elastic modulus was calculated by a conventional method.

<Glass transition temperature>
The glass transition temperature was determined by differential scanning calorimetry (DSC) according to a conventional method.

<Molecular weight>
A sample of the binder resin material was added to THF (tetrahydrofuran) so that the concentration of the resin in the solution was 0.4 mass%, stirred at room temperature for 1 hour, and then allowed to stand for 24 hours. Next, the resulting resin solution was diluted 4 times with THF, and then passed through a 0.45 μm filter. The filtrate was subjected to GPC to obtain a number average molecular weight, a weight average molecular weight, and a dispersion ratio (Mw / Mn). Asked.

When the obtained sample is a conductive paste after preparation or a cured product of the paste, the paste material is added to THF (tetrahydrofuran) so that the concentration of the sample in the solution is 2.0% by mass, and the solution is stirred. While raising the temperature to the boiling point of THF, the mixture was kept for 30 minutes, cooled to room temperature, and left for 24 hours. Next, the obtained resin solution was diluted 4 times with THF, passed through a 0.45 μm filter to remove inorganic matters, GPC measurement was performed on the filtrate, and low molecular weight components such as additives were added with a molecular weight of 500 The number average molecular weight, the weight average molecular weight, and the dispersion ratio (Mw / Mn) were determined for portions having a molecular weight of 500 or more.

<Resin recovery rate>
The resin material was formed into a sheet shape with an arbitrary thickness in the range of 20 μm to 200 μm, and then punched into a dumbbell mold defined by ISO 527-2-1A to obtain a test piece.
Subsequently, a mark was placed at a location 33 mm (effective length 66 mm) from the center of the 10 mm wide and 80 mm long portion in the dumbbell-shaped test piece, and the initial distance L ₀ between the marks was measured accurately. Next, the outside of the marked part is clamped, and the 66 mm mark is stretched to an extension length of 79.2 mm (+13.2 mm, corresponding to an extension degree of 20%), then separated from the clamp, and a predetermined temperature (especially placed on at otherwise if no is 25 ° C.) of the fluorine resin sheet was kept in a horizontal direction, measured after stretching distance L ₂ between the marks was determined extension recovery rate according to the following equation.
Initial length L ₀ = 66.0 mm
Extension length L ₁ = 79.2 mm
Length after extension L ₂ = Measured Elongation L ₃ = L ₁ -L ₀ = 13.2 mm
Recovery length L ₄ = L ₁ -L ₂
Elongation recovery rate = ((L ₁ −L ₂ ) / (L ₁ −L ₀ )) × 100 [%]

<Stretch recovery rate of fabric>
The fabric material was punched into a dumbbell shape specified by ISO 527-2-1A to obtain a test piece. In addition, the extending | stretching direction of the fabric was made into the length direction of a dumbbell.
Next, as in the measurement of the stretch recovery rate of the resin, marks are placed at 33 mm positions (effective length 66 mm) from the center of the 10 mm width and 80 mm length in the dumbbell-shaped test piece, and the stretch length is 99 mm (+33 mm). The elongation recovery rate was determined by operating in the same manner as the resin stretch recovery rate except that the elongation was extended to 50%.

<Heat resistance of fabric>
JIS L1013: 2010 Chemical fiber filament yarn test method The heat shrinkage temperature obtained in 8.19.2 was defined as the heat resistance of the fabric.

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

<Conductivity>
When the size of the conductor sheet is sufficient, it is punched into a dumbbell type specified by ISO 527-2-1A, and the dumbbell type test piece is 10 mm wide and 80 mm long as the test piece. Using. When the conductor sheet could be molded, it was heat-compressed into a sheet having a thickness of 200 ± 20 μm, then punched into a dumbbell shape defined by ISO 527-2-1A, and similarly a test piece was obtained. When the size of the conductor sheet is small and the specified dumbbell shape cannot be obtained, a rectangle with a width and length that can be collected is cut out to make a test piece, and the width, thickness, and length of the measured conductivity are measured. It converted using.
Test piece: The resistance value [Ω] of a portion having a width of 10 mm and a length of 80 mm was measured using a milliohm meter manufactured by Agilent Technologies, and the sheet resistance value “Ω” was multiplied by the aspect ratio (1/8) of the test piece. □ ”.
The resistivity [Ω] was multiplied by the cross-sectional area (width 1 [cm] mm × thickness [cm]) and divided by the length (8 cm) to obtain the specific resistance [Ωcm]. Furthermore, the reciprocal of the specific resistance was determined and used as the conductivity.

<Elongation recovery rate of conductive sheet material>
A test piece similar to that used for the measurement of conductivity was used.
Next, as in the measurement of the stretch recovery rate of the resin, marks are placed at 33 mm positions (effective length 66 mm) from the center of the 10 mm width and 80 mm length in the dumbbell-shaped test piece, and the stretch length is 99 mm (+33 mm). The elongation recovery rate of the conductive sheet was determined in the same manner as the resin extension recovery rate except that the elongation was extended to 50%.

<Repeated stretch durability of conductive sheet material (mechanical load test)>
(1) Preparation of test piece When the size of the conductor sheet was sufficient, it was punched into a dumbbell shape specified by ISO 527-2-1A to obtain a test piece. When the conductor sheet can be molded, it is formed into a sheet having an arbitrary thickness of 20 to 200 μm, and then punched into a dumbbell shape defined by ISO 527-2-1A to obtain a test piece. . When the size of the conductor sheet is small and the specified dumbbell shape cannot be obtained, a rectangle with a width and length that can be collected is cut out to make a test piece, and the width, thickness, and length of the measured conductivity are measured. It converted using.
(2) Repeated expansion and contraction test The IPC bending tester made by Yamashita Material was remodeled, the reciprocating stroke of the tester was set to 13.2 mm, the test piece was clamped on the movable plate side, and the other end was clamped to another fixed end. Fixed at, and adjusted to an effective length of 66 mm (corresponding to an elongation of 20%) by using a 10 mm wide and 80 mm long portion in the dumbbell-shaped test piece so that the sample can be repeatedly stretched. Using a modified device, aluminum foil was wrapped around 0 to 5 mm outside the ends of 66 mm, which had an effective length of expansion and contraction, and was sandwiched between metal clips, and repeatedly stretched while monitoring the resistance value with a tester. Reading of resistance value is repeated every 10 times up to 600 times of extension, and every 50 times more than 600 times, with the extension rate being 0%, and the value after 1 minute is read and recorded, The number of times when the resistance value reached 100 times the initial value was recorded, and the test was terminated there.

<Heating conductivity recovery rate of stretchable conductor layer and stretchable conductor / fabric laminate>
In the case of repeated stretch durability (mechanical load) of the conductive sheet, when the conductivity reduction ratio is 1/1000 or more, the test piece after the repeated stretch durability (mechanical load) test is removed from the tensile load and its own weight Rest on a fluororesin sheet held horizontally in a state where no other load is applied, heat at 60 ° C. for 10 minutes in a dry oven, return to room temperature, measure conductivity, and restore conductivity The rate was determined. Similarly, the stretchable conductor / fabric laminate is allowed to stand on a fluororesin sheet that is horizontally held in a state where no load other than its own weight is applied, and after heating in a dry oven at 60 ° C. for 10 minutes, It returned to room temperature, the electrical conductivity was measured, and the electroconductive recovery rate was calculated | required.
(Equation 3)
Conductivity decrease ratio = Measurement conductivity / initial conductivity Conductivity recovery rate = 100 × 60 ° C. conductivity after heating / initial conductivity

<Thickness unevenness>
The stretchable conductor layer was immersed in liquid nitrogen and sufficiently cooled, and then bent in an arbitrary direction to break the sheet to obtain a test piece capable of observing a cross section. The cross section of the obtained test piece was observed with a microscope having a length measuring function, and the thickness of the conductor portion of the stretchable conductor layer was measured at intervals of about 1 mm in the plane direction. Asked. From the obtained 10 maximum film thicknesses, minimum film thicknesses, and average film thicknesses, film thickness unevenness was determined according to the following equation.
(Equation 4)
Film thickness unevenness [%] = 100 × (maximum film thickness−minimum film thickness) / average film thickness

<Washing durability>
(1) Preparation of test piece A stretchable conductor layer punched into a dumbbell shape was punched into 40 mm × 180 mm at almost the center of a 50 mm × 200 mm fabric (tricot knitted fabric, heat resistance> 100 ° C., stretch recovery rate 100%). A hot melt adhesive layer MOB100 [manufactured by Nisshinbo Co., Ltd.] was stacked, sandwiched between fluororesin sheets, and hot-pressed at 120 ° C. to obtain a test piece. Note that the tricot knitted fabric and the hot melt adhesive layer MOB100 both have sufficient stretchability, with a stretch recovery rate of 100% when stretched 100%.
(2) Washing test
A 30-cycle washing test was conducted according to the 105 method defined in JIS L 0217 Textile Handling Symbols and Display Methods.
Washing solution: neutral detergent 0.5% solution water flow: weak bath ratio: 1:60
Washing cycle Washing 30 ° C 5 minutes Rinse 30 ° C 2 minutes 2 times This cycle is 1 cycle 30 times.
(3) Evaluation In the washing test of the conductive sheet, when the ratio of decrease in conductivity after the test is 1/1000 or more, the test piece after the washing test is removed from the extension load and no load other than its own weight is applied. The sample was allowed to stand on a fluororesin sheet held in a horizontal direction, heated in a dry oven at 60 ° C. for 10 minutes, then returned to room temperature, and the conductivity was measured to obtain the conductivity recovery rate.
Conductivity reduction ratio after washing test = conductivity after washing test / initial conductivity Conductivity recovery after washing test = conductivity after heating at 100 × 60 ° C./initial conductivity after washing test.
In calculating the electrical conductivity, the value of the sheet thickness before being attached to the fabric was used for convenience.

[Production Examples 1 to 5]
<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 part by weight Triethanolamine 0.2 part by weight Sodium carbonate 0.1 part by weight was charged, and the bath temperature was kept at 5 ° C while flowing nitrogen, followed by gentle stirring. Next, an aqueous solution obtained by dissolving 3 parts by mass of potassium persulfate in 19.7 parts by mass of deionized water was added dropwise over 30 minutes, and the reaction was continued for another 20 hours. Then, 0.5 part by mass of hydroquinone was added to 19.5 parts of deionized water. An aqueous solution dissolved in parts by mass was added to stop the polymerization.
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. Table 1 shows the glass transition temperature, number average molecular weight, weight average molecular weight, dispersion ratio, gel fraction, and resin elongation recovery rate of the obtained synthetic rubber resin.
Hereinafter, by changing the addition amount of the polymerization initiator (potassium persulfate), the polymerization temperature, and the raw material charge ratio, Table 1. NBR1, NBR2, NBR3, NBR4 and SBR1 were obtained.

 

[Binder resin]
A resin material was blended at a blending ratio shown in Table 2, and kneaded at a temperature at which the resin material was sufficiently melted to obtain a binder resin. Table 2 shows the characteristics of each binder resin. Shown in
In the table, in the SBR + crosslinking agent, SBR is SBR1 obtained in the production example, and as the crosslinking agent, non-sulfur perbutyl P [manufactured by NOF Corporation] is 0.1% by mass with respect to the total amount of the resin. did
UR-8700 [Toyobo Co., Ltd.] was used as the urethane in the table.

 

[Paste]
First, the binder resin is dissolved in half the amount of the predetermined solvent, and the resulting solution is added with metal-based particles, carbon-based particles, and other components, premixed, and then dispersed in a three-roll mill. The paste shown in Table 3 was obtained as Pag1. Similarly, the paste was adjusted at the composition ratio shown in Table 3.

 

Table 3. Carbon-based particles CB01: scale-like graphite BF-1AT (average particle size 1 μm) manufactured by Chuetsu Graphite Co., Ltd.
Carbon particle CB02: Graphite powder made by Lion Specialty Chemicals Ketjen Black EC300J BET specific surface area 800 (m2 / g)
Metal-based particles Ag01: Fine flaky silver powder Ag-XF301 (average particle size 6 μm) manufactured by Fukuda Metal Foil Powder Co., Ltd.
Metal-based particles Ag02: Agglomerated silver powder G-35 (average particle size 6.0 μm) manufactured by DOWA Electronics Co., Ltd.
Metal-based particles Ag03: Fine size silver powder SPQ03R (Mitsui Metal Mining Co., Ltd.) (average particle size 0.7μm)
Non-conductive particles TiO2: Titanium oxide particles R-62N manufactured by Sakai Chemical Industry Co., Ltd. (average particle size is 0.3 μm)
Non-conductive particles SiO2: Fumed silica AEROSIL 200 (BET specific surface area 200m2 / g) manufactured by Nihon Aerosil
Solvent BC: butyl carbitol acetate solvent IP: isophorone.

By applying the obtained paste for forming an elastic conductor onto a polyester film having a width of 600 mm and treated with a silicone release agent so as to have an effective width of 500 mm using a comma coater, the expansion and contraction shown in Table 4 is achieved. A conductive conductor layer was obtained.
The obtained sheet | seat was peeled from the polyester film by which the mold release process was carried out, and thickness and thickness spot were evaluated. The results are shown in Table 4. Shown in Subsequently, the initial conductivity of the stretchable conductor layer and the conductivity after mechanical loading (after repeated stretch durability test) were evaluated to determine the conductivity reduction ratio. Furthermore, the heating conductivity recovery rate of the stretchable conductor layer after mechanical loading was determined. The results are shown in Table 4. In a sample using a binder resin having a narrow molecular weight distribution, the decrease in conductivity is significant. Furthermore, the conductivity recovery effect by heating is low for samples having a conductivity reduction ratio of 1/1000 or less. It can also be seen that when a binder resin having a wide molecular weight distribution is used, the recovery rate of the conductivity by heating is high.

 

 

The obtained stretchable conductor layer was attached to a tricot fabric by a predetermined method to obtain a stretchable conductor / fabric laminate. The initial conductivity of the stretchable conductor portion of the obtained stretchable conductor / fabric laminate, the conductivity after the washing test, the conductivity decrease ratio after the washing test, and the conductivity recovery rate after the washing test are shown. 4 shows.

[Paste Formation Example 2] Preparation of Electrode Surface Layer Paste (Stretchable Carbon Paste) According to the composition shown in Table 3, an electrode surface layer carbon paste was prepared.

[Paste Formation Example 3] Stretchable Insulating Polymer Layer Forming Paste (Stretchable Insulating Ink: Cover Coat Resin Ink, Underlayer Ink)
A paste for forming a stretchable insulating polymer layer was prepared according to the composition shown in Table 3. Table 5 shows the properties of the film obtained from the obtained paste for stretchable insulating polymer layer formation.

[Application Example 1]
A clothes-type electronic device for measuring an electrocardiogram was manufactured by the direct printing method shown in FIG. The knit sports shirt was turned upside down and put on the temporary support so that there were no wrinkles on the back, and pins were fixed on both shoulders and left and right hems of the shirt.
Next, in the wiring including the conductor pattern shown in FIG. 5, the stretchable conductor layer is made of the stretchable conductor forming paste Pag5 and the stretchable cover layer is made of the stretchable insulating polymer layer forming paste Pcc1 according to the process shown in FIG. Further, a stretchable carbon layer is printed using the electrode surface layer paste Pcb1, screen-printed on each layer, dried and cured under predetermined conditions, printed and laminated, and a sport having electrodes and wiring for electrocardiogram measurement I got a shirt. The electrode surface layer for electrocardiogram measurement is a circle with a diameter of 30 mm. The insulating cover layer has a donut shape with an inner diameter of 30 mm and an outer diameter of 36 mm at the electrode portion, the wiring portion extending from the electrode has a width of 14 mm, and the end of the wiring portion has a diameter of 10 mm to attach a hook for connection with the sensor. The circular electrodes are similarly printed with carbon paste. The carbon paste layer has a dry film thickness of 18 μm, the insulating cover layer has a thickness of 30 μm, and the stretchable conductor layer has a thickness of 28 μm. Prior to printing the stretchable conductor layer, although not shown in the figure, the base layer is formed with a stretchable insulating polymer layer forming paste. ,

The resulting sports shirt with electrodes and wiring has a circular electrode with a diameter of 30 mm at the intersection of the left and right posterior axillary lines and the seventh rib, and a stretchable conductor with a width of 10 mm from the circular electrode to the center of the rear neck Electrical wiring is formed on the inside. The wiring extending from the left and right electrodes to the center of the rear neck has a gap of 5 mm at the center of the neck, and both are not short-circuited.
Subsequently, a stainless steel hook is attached to the surface side of the central end of the rear neck, and a stretchable conductor composition layer using a conductive thread twisted with a thin metal wire to ensure electrical continuity with the wiring part on the back side And a stainless steel hook were electrically connected.

Connect a heart rate sensor WHS-2 made by Union Tool through a stainless steel hook, and receive heart rate data with an Apple smartphone incorporating 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. FIG. 5 shows the wiring pattern, and FIG. 4 shows the layout of the wiring pattern with respect to the shirt.
The subject was wearing this sports shirt, and sports training was performed while acquiring electrocardiographic data. The obtained electrocardiogram data has low noise, high resolution, and the quality that can be analyzed from the heartbeat interval change, electrocardiogram waveform, etc. of the mental state, physical condition, fatigue, drowsiness, tension etc. .
This sports shirt was washed every time after training, and the electrode part and the wiring part were heat-treated with a domestic iron whose surface temperature was adjusted to 80 ° C. after drying. In the heat treatment, a sports shirt that is turned inside out is placed on an ironing board in the same way as with normal ironing, and a 38 μm-thick polyimide film XENOMAX (manufactured by Toyobo Co., Ltd.) is placed on the wiring part as a release sheet. Then, the operation of moving at a speed of 5 to 10 cm / second was repeated 5 times.
By performing such washing and ironing after drying each time, it was possible to maintain a state in which electrocardiographic measurement could be satisfactorily performed even after 100 times of use.

On the other hand, in the sports shirt that was used in the same manner except that the ironing process was omitted, the electrocardiographic noise increased after 30 washings, making it difficult to measure the electrocardiogram during training. After 31 times, by performing the ironing process, it was possible to maintain a state where electrocardiogram measurement was possible up to 80 times.

[Application Example 2]
A sports shirt having wiring of the same pattern as in Application Example 1 was used, except that Pag11 was used as a stretchable conductor forming paste and Pcc2 was used as a stretchable insulating polymer layer forming paste by the print transfer method shown in FIG. A prototype was made using the same material. Using the obtained sport shirt, sport training was performed while taking electrocardiogram data in the same manner as in Application Example 1, and washing, drying, and ironing were repeated in the same manner. As a result, also in the application example 2, the sportswear maintained a state where the electrocardiogram measurement was possible even after 100 times of use.

[Application Example 3]
A sports shirt having the same pattern wiring as Application Example 1 was used by the printing transfer method shown in FIG. 3, except that Pag11 was used as the stretchable conductor forming paste and Pcc3 was used as the stretchable insulating polymer layer forming paste. A prototype was made using the same material. Using the obtained sport shirt, sport training was performed while taking electrocardiogram data in the same manner as in Application Example 1, and washing, drying, and ironing were repeated in the same manner. As a result, also in the application example 3, the sportswear maintained the state where the electrocardiogram measurement was possible even after 100 times of use.

[Application Example 4]
Using the stretchable conductor layer obtained from the paste Pag4 for stretchable conductor formation in Example 1, and using the elastomer sheet “Mobilon” with a hot melt layer made by Nisshinbo Co., Ltd. as the stretchable insulating polymer layer, the electrode surface The sports shirt with electrodes and wiring was obtained by omitting the layers and cutting each sheet into a predetermined shape and laminating and laminating.
Thereafter, sport training was performed while taking electrocardiogram data in the same manner as in Application Example 1, and washing, drying, and ironing were repeated in the same manner. Results In Application Example 3, the sportswear maintained a state where electrocardiogram measurement was possible even after a total of 250 uses.

Industrial application fields

As described above, the stretchable electrical wiring obtained by using the stretchable insulating polymer layer and the stretchable conductor layer in the present invention has a characteristic that the reduced conductivity is regenerated by appropriately performing the heat treatment. Therefore, it has a useful characteristic that a practical life can be extended by using household equipment without using a special device.
By using the stretchable electrical wiring of the present invention for a wearable smart device, information on the human body, i.e., biopotentials such as myoelectric potential and cardiac potential, biological information such as body temperature, pulse, blood pressure, etc. provided on clothes Wearable device for detection, or clothing incorporating an electrical heating device, wearable device incorporating a sensor for measuring clothing pressure, clothing for measuring body size using clothing pressure, sole of foot Socks-type devices for measuring pressure, wiring parts such as clothes, tents and bags with flexible solar cell modules integrated in textiles, low-frequency treatment devices with joints, wiring parts such as thermotherapy machines, flexion degree It can be applied to sensing parts. 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 can also be applied as a wiring material for implant devices to be embedded in the body.

1. Fabric 2. Temporary support 3. 3. Stretchable conductor composition layer Elastic cover layer5. Stretchable carbon layer6. Release support 7. Adhesive layer

Claims (15)

1. In a stretchable conductor sheet composed of a conductive filler and a binder resin, the film thickness unevenness of the sheet is 10% or less, and the stretch recovery rate after stretching 20% at 25 ° C. is 92% or more. A stretchable conductor sheet.
2. The stretchable conductor sheet according to claim 1, wherein after 20% stretching at 25 ° C, the stretch recovery rate is 96% or more when heated at 60 ° C with the stretching load removed.
3. The initial conductivity of the stretchable conductor sheet in the sheet surface direction is 1 × 10 ² S / cm or more,
   When the electrical conductivity reduction ratio due to mechanical load is in the range of 1/1000 or more of the initial electrical conductivity,
   The stretchable conductor sheet according to claim 1 or 2, wherein a conductivity recovery rate by heating at 60 ° C is 10% or more.
4. Consists of 65 to 85% by mass of binder resin with a glass transition temperature of 0 ° C. or lower and a conductive filler of 15 to 35% by mass comprising 90% by mass or more of metal particles with an extension recovery rate after 20% elongation of 99% or more The stretchable conductor sheet according to any one of claims 1 to 3.
5. When the number average molecular weight of the binder resin is Mn and the weight average molecular weight is Mw,
   The elastic conductor sheet according to any one of claims 1 to 4, wherein Mw / Mn> 4 or more.
6. 6. An elastic fabric having an insulating fabric layer having an elongation recovery rate of 99% or more at 50% elongation and a heat resistance of 60 ° C. or more, and the stretchable conductor sheet layer according to claim 1. Conductor / fabric laminate.
7. The stretchable conductor sheet according to any one of claims 1 to 5 or the stretchability according to claim 6, wherein the stretchable conductor sheet is heated to 60 ° C or higher in a state where an extension load of the stretchable conductor sheet is removed. Method for recovering conductivity of conductor / fabric laminate.
8. at least,
   A stretchable insulating polymer layer having a tensile yield elongation of 70% or more and a thermal deformation temperature of 60 ° C or more;
   Stretchable conductor layer composed of conductive filler and binder resin,
   Elastic wiring composed of
9. The stretchable wiring according to claim 8, wherein the stretchable conductor layer has a stretch recovery rate of 92% or more after 20% stretch at 25 ° C.
10. The initial conductivity in the surface direction of the stretchable conductor layer is 1 × 10 ² S / cm or more,
    When the electrical conductivity reduction ratio due to mechanical load is in the range of 1/1000 or more of the initial electrical conductivity,
    The stretchable wiring according to claim 8 or 9, wherein a conductivity recovery rate by heating at 60 ° C is 10% or more.
11. The stretchable conductor layer has a stretch recovery rate after stretching 20% of 99% or more, a conductive resin comprising 65 to 85% by weight of a binder resin having a glass transition temperature of 0 ° C. or less and 90% by weight or more of metal particles. The stretchable wiring according to any one of claims 8 to 10, comprising 15 to 35% by mass.
12. When the number average molecular weight of the binder resin is Mn and the weight average molecular weight is Mw,
    The stretchable wiring according to any one of claims 8 to 11, wherein Mw / Mn> 4 or more.
13. It has the stretchable rate according to any one of claims 8 to 12 on an insulating fabric having a stretch recovery rate of 99% or more when stretched by 50% and having heat resistance of 60 ° C or more. Fabric with elastic wiring.
14. The method for recovering the conductivity of the stretchable wiring according to any one of claims 8 to 12, wherein the stretched wiring is heated to 60 ° C or higher in a state where an extension load of the stretchable wiring is removed.
15. The method for recovering electrical conductivity of a fabric with stretchable wiring according to claim 14, wherein the fabric with stretchable wiring is heated to 60 ° C. or higher in a state in which an extension load of the fabric with stretchable wiring is removed.
    
    
    
    

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