Sheet-shaped conductive member and sheet-shaped heater

Abstract

A sheet-like conductive member (100) includes a dummy sheet structure (2) composed of a plurality of conductive linear materials (21) arranged at intervals. In a plan view of the sheet-like conductive member (100), the conductive linear materials (21) assume a wavy shape formed by providing a second wave along a virtual first wave, the second wave being smaller in amplitude and wavelength than the first wave.

Description

Technical Field

[0001] The present invention relates to a sheet-like conductive member and a sheet-like heater.

Background Art

[0002] A sheet-like conductive member having a pseudo-sheet structure in which a plurality of conductive linear bodies are arranged at intervals (hereinafter, also referred to as a "conductive sheet") may be used as a member of various articles such as a heating element of a heating device, a material of a heat-generating textile, and a protective film for a display (anti-crushing film). As a sheet used for a heating element, for example, Patent Document 1 describes a conductive sheet having a pseudo-sheet structure in which a plurality of conductive linear bodies extending in one direction are arranged at intervals. And this conductive linear body has a first part having a waveform with a wavelength λ1 and an amplitude A1, and a second part having a waveform with a wavelength λ2 and an amplitude A2 different from at least one of the wavelength λ1 and the amplitude A1 of this first part.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the conductive sheet described in Patent Document 1, since the conductive linear body has a waveform, the extensibility of the conductive sheet is improved, that is, when the conductive sheet is stretched, breakage of the conductive linear body can be prevented. However, depending on the use of the conductive sheet, further improvement in extensibility is required.

[0005] An object of the present invention is to provide a sheet-like conductive member and a sheet-like heater having high extensibility.

Means for Solving the Problems

[0006] A sheet-like conductive member according to one aspect of the present invention is a sheet-like conductive member including a pseudo-sheet structure body composed of a plurality of conductive linear bodies arranged at intervals, wherein the conductive linear bodies are wave-shaped in a plan view of the sheet-like conductive member, and the wave shape is a shape in which a second wave having an amplitude and a wavelength shorter than those of the first wave is provided along a virtual first wave.

[0007] In the sheet-like conductive member according to one aspect of the present invention, when the amplitude of the first wave is A1 and the wavelength of the first wave is λ1, it is preferable to satisfy the following mathematical formula (F1). 1 / 20 ≦ A1 / λ1 ≦ 1 ···(F1)

[0008] In the sheet-like conductive member according to one aspect of the present invention, when the amplitude of the first wave is A1 and the amplitude of the second wave is A2, it is preferable to satisfy the following mathematical formula (F2). 1 / 10 ≦ A2 / A1 ≦ 3 / 5 ···(F2)

[0009] In the sheet-like conductive member according to one aspect of the present invention, when the wavelength of the first wave is λ1 and the wavelength of the second wave is λ2, it is preferable to satisfy the following mathematical formula (F3). 1 / 21 ≦ λ2 / λ1 ≦ 1 / 3 ···(F3)

[0010] In the sheet-like conductive member according to one aspect of the present invention, the conductive linear body is preferably at least one selected from the group consisting of a linear body including a metal wire, a linear body including a carbon nanotube, and a linear body having a conductive coating applied to a thread.

[0011] In the sheet-like conductive member according to one aspect of the present invention, it is preferable to further include a stretchable base material that supports the pseudo-sheet structure body.

[0012] In the sheet-like conductive member according to one aspect of the present invention, it is preferably used as a heating element.

[0013] The sheet-shaped heater according to one aspect of the present invention is characterized by including the sheet-shaped conductive member according to one aspect of the present invention described above.

[0014] According to the present invention, a sheet-shaped conductive member and a sheet-shaped heater having high extensibility can be provided.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0016] [First Embodiment] Hereinafter, the present invention will be described with reference to the drawings by taking embodiments as examples. The present invention is not limited to the contents of the embodiments. In the drawings, there are parts that are illustrated enlarged or reduced for ease of explanation.

[0017] (Sheet-shaped Conductive Member) As shown in FIGS. 1 and 2, the sheet-shaped conductive member 100 according to the present embodiment includes a base material 1, a pseudo-sheet structure 2, and a resin layer 3. Specifically, in the sheet-shaped conductive member 100, the resin layer 3 is laminated on the base material 1, and the pseudo-sheet structure 2 is laminated on the resin layer 3. And in the present embodiment, the conductive linear body 21 in the pseudo-sheet structure 2 is in the waveform described below in a plan view of the sheet-shaped conductive member 100.

[0018] (Suspected sheet structure) The suspected sheet structure 2 has a structure in which a plurality of conductive linear bodies 21 are arranged at intervals from each other. That is, the suspected sheet structure 2 is a structure in which a plurality of conductive linear bodies 21 are arranged at intervals from each other so as to form a plane or a curved surface. The conductive linear body 21 is wave-shaped in a plan view of the sheet-like conductive member 100. And the suspected sheet structure 2 has a structure in which a plurality of conductive linear bodies 21 are arranged in a direction orthogonal to the axial direction of the conductive linear body 21.

[0019] The wave shape of the conductive linear body 21 is, for example, a shape in which a second wave W2 having an amplitude and a wavelength shorter than those of the first wave W1 is provided along a virtual first wave W1 as shown in FIG. 3. In addition, the mathematical formula of this wave shape can be expressed as f(x)+g(x) when the mathematical formula of the first wave W1 is f(x) and the mathematical formula of the second wave W2 is g(x). In this specification, the wave shape expressed by the mathematical formula f(x)+g(x) is sometimes also referred to as a "synthetic composite wave shape".

[0020] The wave shape of the conductive linear body 21 may be, for example, a shape in which a second wave W2 having an amplitude and a wavelength shorter than those of the first wave W1 is added in a direction perpendicular to the first wave W1 along the virtual first wave W1 as shown in FIG. 4. In this specification, the wave shape having this shape is sometimes also referred to as a "fractal composite wave shape".

[0021] Examples of the waveforms of the first wave W1 and the second wave W2 include a sine wave, a semi-circular wave, a rectangular wave, a triangular wave, and a sawtooth wave. Among these, from the viewpoint of the stretchability of the sheet-like conductive member 100, a sine wave or a semi-circular wave is preferable. Further, from the viewpoint of suppressing the risk of overlap or contact between the conductive linear bodies 21 when the conductive linear body 21 is processed into a wave shape, a semi-circular wave is more preferable. Also, the waveform of the first wave W1 may be the same as or different from the waveform of the second wave W2. Note that the semi-circular wave is a waveform in which a semi-circle convex in the mountain direction (up) of the wave and a semi-circle convex in the valley direction (down) of the wave appear alternately.

[0022] If the conductive linear body 21 has the above-described waveform, when the sheet-like conductive member 100 is extended in the axial direction of the conductive linear body 21 (the traveling direction of the first wave W1), cutting of the conductive linear body 21 can be suppressed. That is, since the conductive linear body 21 has a waveform, its path length is longer compared to the case where it is linear. Further, the above-described waveform has a longer path length compared to the case where the waveform is a single wave. Therefore, when the sheet-like conductive member 100 is extended in the axial direction of the conductive linear body 21 (the traveling direction of the first wave W1), it has high extensibility. Note that even when the sheet-like conductive member 100 is extended in a direction orthogonal to the axial direction of the conductive linear body 21 (hereinafter also referred to as the "orthogonal direction"), the conductive linear body 21 is not cut. Therefore, the sheet-like conductive member 100 has sufficient extensibility.

[0023] When the sheet-like conductive member 100 is extended in the traveling direction of the first wave W1 of the conductive linear body 21, the elongation rate is preferably 50% or more, more preferably 70% or more, and even more preferably 100% or more. If this elongation rate is 50% or more, it can also be applied to the curved surface of the adherend or the like. Further, in the direction orthogonal to the traveling direction of the first wave W1 of the conductive linear body 21 of the sheet-like conductive member 100, the elongation rate is preferably 50% or more, more preferably 70% or more, and even more preferably 100% or more. If this elongation rate is 50% or more, it can also be applied to the curved surface of the adherend or the like. Here, the elongation rate of the sheet-like conductive member 100 in the present invention is represented by the following formula, where the length of the sheet-like conductive member 100 is A, and the sheet-like conductive member 100 is extended in a predetermined direction, and the length of the sheet-like conductive member 100 when the conductive linear body 21 is cut is B. Note that the presence or absence of cutting of the conductive linear body 21 can be determined by measuring the electrical resistance value of the conductive linear body 21 when the sheet-like conductive member 100 is extended. Elongation rate (%) = {(B - A) / A} × 100

[0024] In the present embodiment, when the amplitude of the first wave W1 is A1 [mm] and the wavelength of the first wave W1 is λ1 [mm], it is preferable to satisfy the following mathematical formula (F1). 1 / 20 ≦ A1 / λ1 ≦ 1 ···(F1)

[0025] If the value of A1 / λ1 is within the above range, the elongation rate of the sheet-like conductive member 100 can be further improved, the distance between adjacent conductive linear bodies 21 can be ensured, and the contact between adjacent conductive linear bodies 21 can be prevented. Further, from the above viewpoints, the value of A1 / λ1 is more preferably 7 / 20 or more and 3 / 5 or less.

[0026] The amplitude A1 of the first wave W1 is preferably 1 mm or more and 200 mm or less, and more preferably 2 mm or more and 50 mm or less. If the amplitude A1 of the first wave W1 is within the above range, the elongation rate of the sheet-like conductive member 100 can be further improved.

[0027] The wavelength λ1 of the first wave W1 is preferably 1 mm or more and 200 mm or less, and more preferably 2 mm or more and 100 mm or less. If the wavelength λ1 of the first wave W1 is within the above range, the elongation rate of the sheet-like conductive member 100 can be further improved.

[0028] In the present embodiment, when the amplitude of the first wave W1 is A1 [mm] and the amplitude of the second wave W2 is A2 [mm], it is preferable to satisfy the following mathematical formula (F2). 1 / 10 ≦ A2 / A1 ≦ 3 / 5 ···(F2)

[0029] If the value of A2 / A1 is within the above range, the elongation rate of the sheet-like conductive member 100 can be further improved, the distance between adjacent conductive linear bodies 21 can be ensured, and the contact between adjacent conductive linear bodies 21 can be prevented. Further, from the above viewpoints, the value of A2 / A1 is more preferably 1 / 5 or more and 2 / 5 or less.

[0030] In the present embodiment, when the wavelength of the first wave W1 is λ1 [mm] and the wavelength of the second wave W2 is λ2 [mm], it is preferable to satisfy the following mathematical formula (F3). 1 / 21 ≦ λ2 / λ1 ≦ 1 / 3 ···(F3)

[0031] If the value of λ2 / λ1 is within the above range, the elongation rate of the sheet-like conductive member 100 can be further improved, the distance between adjacent conductive linear bodies 21 can be ensured, and the contact between adjacent conductive linear bodies 21 can be prevented. Also, from the above viewpoints, the value of λ2 / λ1 is more preferably 1 / 15 or more and 1 / 5 or less.

[0032] The volume resistivity R of the conductive linear body 21 is 1.0×10 -9 Ω·m or more and 1.0×10 -3 Ω·m or less, preferably 1.0×10 -8 Ω·m or more and 1.0×10 -4 Ω·m or less. When the volume resistivity R of the conductive linear body 21 is within the above range, the surface resistance of the pseudo-sheet structure 2 is likely to decrease. The measurement of the volume resistivity R of the conductive linear body 21 is as follows. Apply silver paste to one end of the conductive linear body 21 and a portion 40 mm in length from the end, measure the resistance of the end and the portion 40 mm in length from the end, and obtain the resistance value of the conductive linear body 21. Then, multiply the cross-sectional area (unit: m 2 ) of the conductive linear body 21 by the above resistance value and divide the obtained value by the above-measured length (0.04 m) to calculate the volume resistivity of the conductive linear body 21.

[0033] The shape of the cross-section of the conductive linear body 21 is not particularly limited and can be, for example, polygonal, flat, elliptical, or circular. However, from the viewpoint of compatibility with the resin layer 3 and the like, it is preferably elliptical or circular. When the cross-section of the conductive linear body 21 is circular, the thickness (diameter) D of the conductive linear body 21 (see Fig. 2) is preferably 5 μm or more and 3 mm or less. From the viewpoints of suppressing the increase in sheet resistance and improving the heat generation efficiency and insulation breakdown resistance characteristics when the sheet-like conductive member 100 is used as a heating element, the diameter D of the conductive linear body 21 is more preferably 8 μm or more and 60 μm or less, and even more preferably 12 μm or more and 40 μm or less. When the cross-section of the conductive linear body 21 is elliptical, it is preferable that the major axis is in the same range as the above-mentioned diameter D.

[0034] The diameter D of the conductive linear body 21 is measured by observing the conductive linear body 21 of the pseudo-sheet structure 2 using a digital microscope and measuring the diameter of the conductive linear body 21 at five randomly selected locations, and taking the average value.

[0035] The interval L between the conductive linear bodies 21 (see Fig. 2) is preferably 1 mm or more and 400 mm or less, more preferably 2 mm or more and 200 mm or less, and even more preferably 3 mm or more and 100 mm or less. If the interval between the conductive linear bodies 21 is within the above range, since the conductive linear bodies are somewhat dense, it is possible to improve the function of the sheet-like conductive member 100, such as making the temperature rise distribution uniform when the sheet-like conductive member 100 is used as a heating element.

[0036] The interval L between the conductive linear bodies 21 is measured by observing the conductive linear bodies 21 of the pseudo-sheet structure 2 visually or using a digital microscope and measuring the interval between two adjacent conductive linear bodies 21. Note that the interval between two adjacent conductive linear bodies 21 is the length along the direction in which the conductive linear bodies 21 are arranged, and is the length between the opposing portions of the two conductive linear bodies 21 (see Fig. 2). When the arrangement of the conductive linear bodies 21 is uneven, the interval L is the average value of the intervals between all adjacent conductive linear bodies 21.

[0037] The conductive linear body 21 is not particularly limited, but is preferably a linear body including a metal wire (hereinafter also referred to as a "metal wire linear body"). Since the metal wire has high thermal conductivity, high electrical conductivity, high handleability, and versatility, when a metal wire linear body is applied as the conductive linear body 21, while reducing the resistance value of the pseudo-sheet structure 2, it is easy to improve the light transmittance. In addition, when the sheet-like conductive member 100 (pseudo-sheet structure 2) is applied as a heating element, rapid heat generation is easily realized. Furthermore, as described above, it is easy to obtain a linear body with a small diameter. In addition to the metal wire linear body, examples of the conductive linear body 21 include a linear body including a carbon nanotube and a linear body in which a conductive coating is applied to a thread.

[0038] The metal wire linear body may be a linear body composed of a single metal wire or a linear body formed by twisting a plurality of metal wires. Examples of the metal wire include metals such as copper, aluminum, tungsten, iron, molybdenum, nickel, titanium, silver, and gold, or alloys containing two or more metals (for example, steels such as stainless steel and carbon steel, brass, phosphor bronze, zirconium copper alloy, beryllium copper, iron nickel, nichrome, nickel titanium, kanthal, hastelloy, and rhenium tungsten, etc.). The metal wire may also be plated with tin, zinc, silver, nickel, chromium, nickel chromium alloy, or solder, etc., or may have its surface coated with a carbon material or polymer described later. In particular, a wire containing one or more metals selected from tungsten and molybdenum and alloys containing these is preferable from the viewpoint of obtaining a conductive linear body 21 with a low volume resistivity. Examples of the metal wire also include a metal wire coated with a carbon material. When the metal wire is coated with a carbon material, it is easy to reduce the metallic luster and make the presence of the metal wire less noticeable. In addition, when the metal wire is coated with a carbon material, metal corrosion is also suppressed. Examples of carbon materials for coating metal wires include amorphous carbon (such as carbon black, activated carbon, hard carbon, soft carbon, mesoporous carbon, and carbon fiber), graphite, fullerene, graphene, and carbon nanotubes.

[0039] The linear body containing carbon nanotubes is, for example, obtained by pulling out carbon nanotubes in a sheet form from the end of a carbon nanotube forest (a grown body in which a plurality of carbon nanotubes are grown on a substrate so as to be oriented in a direction perpendicular to the substrate, and may also be referred to as an "array"), bundling the pulled-out carbon nanotube sheet, and then twisting the bundle of carbon nanotubes. In such a manufacturing method, when no twist is applied during twisting, a ribbon-shaped carbon nanotube linear body is obtained, and when twist is applied, a thread-shaped linear body is obtained. The ribbon-shaped carbon nanotube linear body is a linear body having a structure in which carbon nanotubes are not twisted. In addition, carbon nanotube linear bodies can also be obtained by spinning from a dispersion of carbon nanotubes. The production of carbon nanotube linear bodies by spinning can be carried out, for example, by the method disclosed in US Patent Application Publication No. 2013 / 0251619 (Japanese Patent Laid-Open No. 2012-126635). From the viewpoint of obtaining uniform diameter of carbon nanotube linear bodies, it is desirable to use thread-shaped carbon nanotube linear bodies, and from the viewpoint of obtaining highly pure carbon nanotube linear bodies, it is preferable to obtain thread-shaped carbon nanotube linear bodies by twisting carbon nanotube sheets. The carbon nanotube linear body may be a linear body in which two or more carbon nanotube linear bodies are braided together. Further, the carbon nanotube linear body may be a linear body in which carbon nanotubes and other conductive materials are composite (hereinafter also referred to as "composite linear body").

[0040] Examples of the composite linear body include: (1) in the process of obtaining a carbon nanotube linear body by pulling out carbon nanotubes in a sheet form from the end of a carbon nanotube forest, bundling the pulled-out carbon nanotube sheet, and then twisting the bundle of carbon nanotubes, a composite linear body in which a simple metal or metal alloy is supported on the surface of the carbon nanotube forest, sheet, bundle, or twisted linear body by vapor deposition, ion plating, sputtering, wet plating, or the like; (2) a composite linear body in which a bundle of carbon nanotubes is twisted together with a simple metal linear body, a metal alloy linear body, or a composite linear body; (3) a composite linear body in which a simple metal linear body, a metal alloy linear body, or a composite linear body is braided with a carbon nanotube linear body or a composite linear body. In the composite linear body of (2), when twisting the bundle of carbon nanotubes, a metal may be supported on the carbon nanotubes in the same manner as in the composite linear body of (1). The composite linear body of (3) is a composite linear body formed by braiding two linear bodies, but if it contains at least one simple metal linear body, a metal alloy linear body, or a composite linear body, it may be formed by braiding three or more carbon nanotube linear bodies, simple metal linear bodies, metal alloy linear bodies, or composite linear bodies. Examples of the metal of the composite linear body include simple metals such as gold, silver, copper, iron, aluminum, nickel, chromium, tin, and zinc, and alloys containing at least one of these simple metals (such as copper-nickel-phosphorus alloy and copper-iron-phosphorus-zinc alloy).

[0041] The conductive linear body 21 may be a linear body in which a conductive coating is applied to a thread. Examples of the thread include threads spun from resins such as nylon and polyester. Examples of the conductive coating include coatings such as metals, conductive polymers, and carbon materials. The conductive coating can be formed by plating, vapor deposition, or the like. A linear body with a conductive coating applied to a thread can improve the conductivity of the linear body while maintaining the flexibility of the thread. That is, it becomes easy to reduce the resistance of the pseudo-sheet structure 2.

[0042] (Base material) Examples of the base material 1 include synthetic resin films, paper, metal foils, nonwoven fabrics, cloth, and glass films. The pseudo-sheet structure 2 can be supported directly or indirectly by this base material 1. Further, the base material 1 is preferably a stretchable base material. As the stretchable base material, a synthetic resin film, a nonwoven fabric, cloth, or the like can be used. Among these stretchable base materials, a synthetic resin film or cloth is preferable, and a synthetic resin film is more preferable. Examples of the synthetic resin film include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polyethylene naphthalate film, a polybutylene terephthalate film, a polyurethane film, an ethylene vinyl acetate copolymer film, an ionomer resin film, an ethylene-(meth)acrylic acid copolymer film, an ethylene-(meth)acrylate copolymer film, a polystyrene film, a polycarbonate film, and a polyimide film. In addition, examples of the stretchable base material include these crosslinked films and laminated films. Examples of the paper include high-quality paper, recycled paper, and kraft paper. Examples of the nonwoven fabric include a spunbond nonwoven fabric, a needle-punched nonwoven fabric, a meltblown nonwoven fabric, and a spunlace nonwoven fabric. Examples of the cloth include woven fabrics and knitted fabrics. The nonwoven fabric and cloth as the stretchable base material are not limited to these.

[0043] (Resin layer) The resin layer 3 is a layer containing a resin. The pseudo-sheet structure 2 can be supported directly or indirectly by this resin layer 3. Further, the resin layer 3 is preferably a layer containing an adhesive. When forming the pseudo-sheet structure 2 on the resin layer 3, the adhesive facilitates the attachment of the conductive linear body 21 to the resin layer 3. Also, when the resin layer 3 is a layer containing an adhesive, the conductive linear body 21 can be easily attached to the base material 1 via the resin layer 3.

[0044] The resin layer 3 may be a layer made of a resin that can be dried or cured. Thereby, sufficient hardness to protect the pseudo-sheet structure 2 is imparted to the resin layer 3, and the resin layer 3 also functions as a protective film. Further, the resin layer 3 after curing or drying has impact resistance and can also suppress deformation of the pseudo-sheet structure 2 due to impact.

[0045] The resin layer 3 is preferably energy-ray curable, such as ultraviolet rays, visible energy rays, infrared rays, electron beams, etc., in that it can be easily cured in a short time. Note that "energy-ray curing" includes heat curing by heating using energy rays.

[0046] Examples of the adhesive for the resin layer 3 include a thermosetting adhesive that cures by heat, a so-called heat-seal type adhesive that adheres by heat, an adhesive that develops adhesiveness when moistened, etc. However, from the viewpoint of ease of application, it is preferable that the resin layer 3 is energy-ray curable. Examples of the energy-ray curable resin include compounds having at least one polymerizable double bond in the molecule, and acrylate compounds having a (meth)acryloyl group are preferable.

[0047] Examples of the acrylate compound include chain aliphatic skeleton-containing (meth)acrylates (such as trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate), cyclic aliphatic skeleton-containing (meth)acrylates (such as dicyclopentanyl di(meth)acrylate and dicyclopentadiene di(meth)acrylate), polyalkylene glycol (meth)acrylates (such as polyethylene glycol di(meth)acrylate), oligoester (meth)acrylates, urethane (meth)acrylate oligomers, epoxy-modified (meth)acrylates, polyethers (meth)acrylates other than the polyalkylene glycol (meth)acrylates, and itaconic acid oligomers).

[0048] The weight average molecular weight (Mw) of the energy ray curable resin is preferably from 100 to 30000, more preferably from 300 to 10000.

[0049] The energy ray curable resin contained in the adhesive composition may be only one kind or two or more kinds. When there are two or more kinds, their combinations and ratios can be arbitrarily selected. Further, it may be combined with the thermoplastic resin described later, and the combinations and ratios can be arbitrarily selected.

[0050] The resin layer 3 may be an adhesive layer formed from an adhesive (pressure-sensitive adhesive). The adhesive of the adhesive layer is not particularly limited. For example, examples of the adhesive include acrylic adhesives, urethane adhesives, rubber adhesives, polyester adhesives, silicone adhesives, and polyvinyl ether adhesives. Among these, it is preferable that the adhesive is at least any one selected from the group consisting of acrylic adhesives, urethane adhesives, and rubber adhesives, and more preferably an acrylic adhesive.

[0051] Examples of the acrylic adhesive include polymers containing structural units derived from alkyl (meth)acrylates having a linear alkyl group or a branched alkyl group (that is, polymers obtained by polymerizing at least alkyl (meth)acrylates), and acrylic polymers containing structural units derived from (meth)acrylates having a cyclic structure (that is, polymers obtained by polymerizing at least (meth)acrylates having a cyclic structure). Here, "(meth)acrylate" is used as a term indicating both "acrylate" and "methacrylate", and the same applies to other similar terms.

[0052] When the acrylic polymer is a copolymer, the form of copolymerization is not particularly limited. The acrylic copolymer may be any of a block copolymer, a random copolymer, or a graft copolymer.

[0053] The acrylic copolymer may be crosslinked with a crosslinking agent. Examples of the crosslinking agent include known epoxy-based crosslinking agents, isocyanate-based crosslinking agents, aziridine-based crosslinking agents, and metal chelate-based crosslinking agents. When crosslinking the acrylic copolymer, functional groups derived from the monomer components of the acrylic polymer, such as hydroxyl groups or carboxyl groups that react with these crosslinking agents, can be introduced into the acrylic copolymer.

[0054] When the resin layer 3 is formed from an adhesive, the resin layer 3 may further contain the above-described energy ray curable resin in addition to the adhesive. Further, when an acrylic adhesive is applied as the adhesive, as the energy ray curable component, a compound having both a functional group that reacts with a functional group derived from a monomer component in an acrylic copolymer and an energy ray polymerizable functional group in one molecule may be used. By the reaction of the functional group of the compound with the functional group derived from the monomer component in the acrylic copolymer, the side chain of the acrylic copolymer becomes polymerizable by energy ray irradiation. Even when the adhesive is other than an acrylic adhesive, as a polymer component other than an acrylic polymer, a component having a side chain that is similarly energy ray polymerizable may be used.

[0055] The thermosetting resin used for the resin layer 3 is not particularly limited, and specifically, epoxy resins, phenol resins, melamine resins, urea resins, polyester resins, urethane resins, acrylic resins, benzoxazine resins, phenoxy resins, amine-based compounds, and acid anhydride-based compounds, etc. may be mentioned. These can be used alone or in combination of two or more. Among these, from the viewpoint of being suitable for curing using an imidazole-based curing catalyst, it is preferable to use epoxy resins, phenol resins, melamine resins, urea resins, amine-based compounds, and acid anhydride-based compounds. In particular, from the viewpoint of exhibiting excellent curability, epoxy resins, phenol resins, mixtures thereof, or a mixture of an epoxy resin and at least one selected from the group consisting of phenol resins, melamine resins, urea resins, amine-based compounds, and acid anhydride-based compounds is preferably used.

[0056] The moisture curable resin used for the resin layer 3 is not particularly limited, and examples include urethane resins, which are resins in which isocyanate groups are generated by moisture, and modified silicone resins.

[0057] When using an energy ray-curable resin or a thermosetting resin, it is preferable to use a photoinitiator or a thermal polymerization initiator or the like. By using a photoinitiator or a thermal polymerization initiator or the like, a crosslinked structure is formed, and it becomes possible to more strongly protect the pseudo-sheet structure 2.

[0058] Examples of the photoinitiator include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin benzoic acid methyl, benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, 2-chloroanthraquinone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenyl-phosphine oxide.

[0059] Examples of the thermal polymerization initiator include hydrogen peroxide, peroxodisulfates (such as ammonium peroxodisulfate, sodium peroxodisulfate, and potassium peroxodisulfate), azo compounds (such as 2,2'-azobis(2-amidinopropane) dihydrochloride, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobisisobutyronitrile, and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile)), and organic peroxides (such as benzoyl peroxide, lauroyl peroxide, peracetic acid, succinic peroxide, di-t-butyl peroxide, t-butyl hydroperoxide, and cumene hydroperoxide).

[0060] These polymerization initiators can be used alone or in combination of two or more. When forming a crosslinked structure using these polymerization initiators, the amount used is preferably 0.1 part by mass or more and 100 parts by mass or less, more preferably 1 part by mass or more and 100 parts by mass or less, and particularly preferably 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the energy ray curable resin or thermosetting resin.

[0061] The resin layer 3 may be a layer made of a thermoplastic resin composition, for example, which is not curable. And by containing a solvent in the thermoplastic resin composition, the thermoplastic resin layer can be softened. Thereby, when forming the pseudo-sheet structure 2 on the resin layer 3, it becomes easy to attach the conductive linear body 21 to the resin layer 3. On the other hand, by volatilizing the solvent in the thermoplastic resin composition, the thermoplastic resin layer can be dried and solidified.

[0062] Examples of the thermoplastic resin include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl acetate, polyurethane, polyether, polyethersulfone, polyimide, and acrylic resin. Examples of the solvent include alcohol solvents, ketone solvents, ester solvents, ether solvents, hydrocarbon solvents, halogenated alkyl solvents, and water.

[0063] The resin layer 3 may contain an inorganic filler. By containing an inorganic filler, the hardness of the resin layer 3 after curing can be further improved. Also, the thermal conductivity of the resin layer 3 is improved.

[0064] Examples of the inorganic filler include inorganic powders (for example, powders such as silica, alumina, talc, calcium carbonate, titanium white, red iron oxide, silicon carbide, and boron nitride), beads obtained by spheroidizing inorganic powders, single crystal fibers, and glass fibers. Among these, as the inorganic filler, silica filler and alumina filler are preferable. The inorganic filler may be used alone or in combination of two or more.

[0065] The resin layer 3 may contain other components. Examples of the other components include well-known additives such as organic solvents, flame retardants, tackifiers, ultraviolet absorbers, antioxidants, preservatives, fungicides, plasticizers, defoamers, and wettability modifiers.

[0066] The thickness of the resin layer 3 is appropriately determined according to the use of the sheet-like conductive member 100. For example, from the viewpoint of adhesiveness, the thickness of the resin layer 3 is preferably 3 μm or more and 150 μm or less, and more preferably 5 μm or more and 100 μm or less.

[0067] (Method for manufacturing a sheet-like conductive member) The method for manufacturing the sheet-like conductive member 100 according to the present embodiment is not particularly limited, and can be manufactured, for example, by the following steps. First, a composition for forming the resin layer 3 is applied onto the base material 1 to form a coating film. Next, the coating film is dried to produce the resin layer 3. Next, while arranging the conductive linear bodies 21, they are disposed on the resin layer 3 to form a pseudo-sheet structure 2. For example, in a state where the resin layer 3 with the base material 1 is disposed on the outer peripheral surface of the drum member, while rotating the drum member, the conductive linear bodies 21 are fed out and spirally wound around the resin layer 3. At this time, by repeatedly performing a small reciprocating motion in a direction intersecting the axial direction (wave propagation direction) of the conductive linear body 21 for the feeding portion of the conductive linear body 21 and moving it so as to result in a large reciprocating motion as a whole, a conductive linear body 21 having a composite wave shape of a synthetic type provided with a virtual second wave W2 along a virtual first wave W1 can be formed. Also, by appropriately selecting the rotation speed of the drum member, the feeding speed of the conductive linear body, and the moving speed and moving distance of the feeding portion, desired waveforms, amplitudes, and wavelengths can be obtained for each of the first wave W1 and the second wave W2 of the conductive linear body. Thereafter, the bundle of the spirally wound conductive linear bodies 21 is cut along the axial direction of the drum member. Thereby, the pseudo-sheet structure 2 is formed and disposed on the resin layer 3. Then, the resin layer 3 with the base material 1 on which the pseudo-sheet structure 2 is formed is taken out from the drum member, and the sheet-like conductive member 100 is obtained.

[0068] As another manufacturing method of the sheet-like conductive member 100, a conductive linear body 21 having a waveform of a second wave W2 is prepared in advance, and while arranging the conductive linear body 21 on a resin layer 3 formed on a base material 1, a pseudo-sheet structure body 2 may be formed. In this case, for example, in a state where the resin layer 3 with the base material 1 is arranged on the outer peripheral surface of the drum member, while rotating the drum member, the conductive linear body 21 having the waveform of the second wave W2 is spirally wound around the resin layer 3. At this time, by reciprocating the feeding portion of the conductive linear body 21 along the direction parallel to the axis of the drum member, a conductive linear body 21 having a waveform in which a virtual second wave W2 is provided along a virtual first wave W1 can be obtained. Then, the sheet-like conductive member 100 is obtained by cutting the bundle of the spirally wound conductive linear bodies 21 along the axial direction of the drum member.

[0069] (Operation and effect of the first embodiment) According to the present embodiment, the following operation and effect can be achieved. (1) In the present embodiment, the waveform of the conductive linear body 21 is a shape in which a second wave W2 having an amplitude and a wavelength shorter than those of the first wave W1 is provided along a virtual first wave W1. Therefore, a sheet-like conductive member 100 having higher extensibility than the conventional one can be obtained. (2) Since the sheet-like conductive member 100 according to the present embodiment has high extensibility, it can be suitably used as a heating element.

[0070] [Second embodiment] Next, a second embodiment of the present invention will be described with reference to the drawings. In the present embodiment, an aspect in which the sheet-like conductive member 100A shown in FIG. 5 is used as a sheet heater will be described. Since the sheet-like conductive member 100A according to the present embodiment has a pseudo-sheet structure body 2 with low surface resistance, it is preferably applied as a sheet heater.

[0071] In addition, in this embodiment, the configuration is the same as that of the first embodiment except that the electrode 4 is attached to the pseudo-sheet structure 2. Therefore, the electrode 4 will be described, and the parts common to the previous description will be omitted. The electrode 4 is used to supply current to the conductive linear body 21. The electrode 4 can be formed using a known electrode material. Examples of the electrode material include conductive paste (such as silver paste), metal foil (such as copper foil), and metal wire. The electrode 4 is disposed to be electrically connected to both ends of the conductive linear body 21. Examples of the metal of the metal foil or metal wire include metals such as copper, aluminum, tungsten, iron, molybdenum, nickel, titanium, silver, and gold, or alloys containing two or more metals (for example, steels such as stainless steel and carbon steel, brass, phosphor bronze, zirconium copper alloy, beryllium copper, iron nickel, nichrome, nickel titanium, kanthal, hastelloy, and rhenium tungsten). Further, the metal foil or metal wire may be plated with tin, zinc, silver, nickel, chromium, nickel chromium alloy, or solder.

[0072] The ratio of the resistance value of the electrode 4 to the pseudo-sheet structure 2 (resistance value of the electrode 4 / resistance value of the pseudo-sheet structure 2) is preferably 0.0001 or more and 0.3 or less, and more preferably 0.0005 or more and 0.1 or less. The ratio of the resistance value of the electrode to the pseudo-sheet structure 2 can be obtained by "resistance value of the electrode 4 / resistance value of the pseudo-sheet structure 2". When the sheet-like conductive member 100A is used as a heating element within this range, abnormal heat generation at the electrode portion is suppressed. When the pseudo-sheet structure 2 is used as a sheet heater, only the pseudo-sheet structure 2 generates heat, and a sheet heater with good heat generation efficiency can be obtained. The resistance values of the electrode 4 and the pseudo-sheet structure 2 can be measured using a tester. First, measure the resistance value of the electrode 4, and then measure the resistance value of the pseudo-sheet structure 2 with the electrode 4 attached. Then, by subtracting the measured value of the electrode 4 from the resistance value of the pseudo-sheet structure 2 with the electrode attached, the resistance values of the electrode 4 and the pseudo-sheet structure 2 can be calculated respectively.

[0073] The thickness of the electrode 4 is preferably 2 μm or more and 200 μm or less, more preferably 2 μm or more and 120 μm or less, and particularly preferably 10 μm or more and 100 μm or less. If the thickness of the electrode is within the above range, the electric conductivity is high, the resistance is low, and the resistance value with the pseudo-sheet structure can be suppressed low. Also, sufficient strength can be obtained as the electrode.

[0074] (Operation and Effect of the Second Embodiment) According to this embodiment, the same operation and effects as the operation and effects (1) and (2) in the first embodiment can be achieved.

[0075] [Modification of the Embodiment] The present invention is not limited to the above-described embodiments, and modifications, improvements, etc. within the range that can achieve the object of the present invention are included in the present invention. For example, in the above-described embodiment, the sheet-like conductive member 100 includes the base material 1, but is not limited thereto. For example, the sheet-like conductive member 100 may not include the base material 1. In such a case, the resin layer 3 can be used to attach the sheet-like conductive member 100 to an adherend for use. In the above-described embodiment, the sheet-like conductive member 100 includes the resin layer 3, but is not limited thereto. For example, the sheet-like conductive member 100 may not include the resin layer 3. In such a case, a knitted fabric may be used as the base material 1, and the conductive linear body 21 may be knitted into the base material 1 to form the pseudo-sheet structure 2. [Examples]

[0076] Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to these examples at all.

[0077] [Examples 1 to 19] An acrylic adhesive (manufactured by Lintec Corporation, trade name "PK") was applied to a polyurethane film with a thickness of 100 μm as a base material to a thickness of 20 μm to form a resin layer, and an adhesive sheet was produced. Using a wire injection device (manufactured by Lintec Corporation), while moving the nozzle on this adhesive sheet, a metal wire (material: tungsten) was injected, and 30 metal wires were arranged to obtain a sheet-shaped conductive member. The cross-section of the metal wire was circular, and its diameter was 80 μm. Also, the metal wire used was pre-formed into the waveform of the second wave. Table 1 shows the type of waveform of the metal wire (conductive linear body) in the obtained sheet-shaped conductive member, the waveform of the first wave, the waveform of the second wave, the value of A1 / λ1, the value of A2 / A1, and the value of λ2 / λ1. The wavelength λ1 of the first wave was 4 mm, and the amplitude A1 of the first wave was 2 mm. Also, the interval between the metal wires was 1 mm.

[0078] [Comparative Example 1] A sheet-shaped conductive member was obtained in the same manner as in Example 1, except that the metal wires were arranged so that the type of waveform, the waveform of the first wave, the waveform of the second wave, the value of A1 / λ1, the value of A2 / A1, and the value of λ2 / λ1 were as shown in Table 1 below.

[0079] [Comparative Example 2] A sheet-shaped conductive member was obtained in the same manner as in Example 1, except that the waveform was a single waveform (sine wave) and the metal wires were arranged so that the value of A1 / λ1 in the sine wave was as shown in Table 1 below.

[0080] [Evaluation of Stretchability] The obtained sheet-shaped conductive member was used as a sample. An adherend on a SUS hemisphere with a radius of 5 mm was prepared, the sample was attached to its surface, left standing for 1 hour, and the occurrence of metal wire breakage, ease of attachment, and peeling was confirmed. Then, the stretchability of the sheet-shaped conductive member was evaluated according to the following criteria. A: Neither wire breakage nor peeling was observed, and the adhesion suitability (ease of attachment) was good. B: Neither wire breakage nor peeling was observed, but due to the difference in followability between the amplitude direction and the wavelength direction, the workability during attachment decreased. C: There was peeling of a part of the wire from the resin layer, but no wire breakage was observed. D: There was peeling off from a large resin layer on the wire and wire breakage.

[0081] [Evaluation of the Possibility of Wire Contact] The possibility of wire contact in the obtained sheet-like conductive member was evaluated according to the following criteria. The obtained results are shown in Table 1. A: The distance between the closest parts of the wires is 0.3 mm or more. B: The distance between the closest parts of the wires is less than 0.3 mm.

[0082]

Table 1

[0083] From the results shown in Table 1, it was confirmed that the sheet-like conductive members obtained in Examples 1 to 19 are excellent in extensibility compared to the sheet-like conductive members obtained in Comparative Examples 1 and 2. From the results of Examples 1 to 6, when the value of A1 / λ1 is 1 / 2, the extensibility is good in the range where the value of A2 / A1 is 1 / 10 or more and 5 / 10 or less, and the extensibility is good in the range where the value of λ2 / λ1 is 1 / 3 or more and 1 / 11 or less. From the results of Examples 14 to 16, it was found that the fractal-type composite wave shape has improved extensibility compared to the synthetic-type composite wave shape. From the results of Examples 17 to 19, it was found that by changing the waveform of the first wave from a sine wave to a semi-circular wave, the extensibility is improved and moreover, the possibility of wire contact can be reduced.

Explanation of Signs

[0084] 1... Substrate, 2... Quasi-sheet structure, 21... Conductive linear body, 3... Resin layer, 100, 100A... Sheet-like conductive member.

Claims

1. A sheet-like conductive member including a pseudo-sheet structure formed by a plurality of spaced-apart conductive linear bodies, wherein the conductive linear bodies are wavy in a plan view of the sheet-like conductive member, the wavy shape is a shape provided with a second wave having an amplitude and a wavelength shorter than those of the first wave along a virtual first wave, when the amplitude of the first wave is A1, the wavelength of the first wave is λ1, and the amplitude of the second wave is A2, the following mathematical formulas (F1) and (F2) are satisfied, sheet-like conductive member. 1 / 20 ≤ A1 / λ1 ≤ 1... (F1) 1 / 10 ≤ A2 / A1 ≤ 3 / 5... (F2)

2. The sheet-like conductive member according to Claim 1, Let the wavelength of the first wave be λ １ and the wavelength of the second wave be λ ２ When this is the case, it satisfies the following mathematical formula (F3). sheet-like conductive member. 1 / 21 ≤ λ ２ / λ １ ≤ 1 / 3... (F3)

3. The sheet-like conductive member according to Claim 1 or Claim 2, wherein the conductive linear body is at least one selected from the group consisting of a linear body including a metal wire, a linear body including a carbon nanotube, and a linear body having a conductive coating applied to a thread, sheet-like conductive member.

4. The sheet-like conductive member according to any one of Claims 1 to 3, further including a stretchable base material that supports the pseudo-sheet structure, sheet-like conductive member.

5. The sheet-like conductive member according to any one of Claims 1 to 4, used as a heating element, sheet-like conductive member.

6. A sheet-like heater including the sheet-like conductive member according to any one of Claims 1 to 5, sheet-like heater.

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