Wiring sheet

Abstract

A wiring sheet (100) is provided with a pseudo-sheet structure (2) in which a plurality of electrically conductive linear bodies (21) are arranged at intervals, and a pair of electrodes (4) which are in direct contact with the electrically conductive linear bodies (21), wherein: each of the pair of electrodes (4) comprises two or more metal wires (41); and each of the pair of electrodes (4) satisfies both formula (F1) and formula (F2), where N is the number of metal wires (41) in one of the pair of electrodes (4), and Rn is the resistance value of an n-th metal wire (41), counting from the outside of the electrodes (4), in a plan view of the wiring sheet (100). (F1): Rn≤Rn+1 (F2): R1<RN

Description

[Technical Field]

[0001] The present invention relates to a wiring sheet. [Background technology]

[0002] A sheet-like conductive member (hereinafter also referred to as "conductive sheet") having a pseudo-sheet structure in which multiple conductive linear elements are arranged at intervals may be useful as a component for a variety of items, such as a heating element for a heating device, a heat-generating textile material, or a protective film for a display (shatter-resistant film). As an example of a sheet used as a heating element, Patent Document 1 describes a conductive sheet having a pseudo-sheet structure in which multiple linear elements extending in one direction are arranged at intervals. A pair of electrodes is provided on both ends of the multiple linear elements, thereby obtaining a wiring sheet that can be used as a heating element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 086395 Summary of the Invention [Problem to be solved by the invention]

[0004] Metal foil or silver paste is typically used as the electrode for a wiring sheet. However, from the viewpoint of the flexibility of the electrode portion of the wiring sheet, the use of metal wire instead of metal foil or silver paste has been considered. On the other hand, when metal wire is used as the electrode, the resistance value of the electrode becomes relatively large. As a result, the difference with the resistance value of the linear body, which is the heat-generating portion, becomes small, and the resistance value of the electrode, which should be negligible, becomes significant. In such cases, the resistance value of the electrode can be reduced by increasing the number of metal wires. From this perspective, a large number of metal wires is preferable. However, it has been found that when an electrode is made of multiple metal wires, the amount of heat generated by each metal wire differs during heating, resulting in large temperature variations within the electrode.

[0005] An object of the present invention is to provide a wiring sheet that can suppress temperature unevenness within an electrode. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a wiring sheet including a pseudo sheet structure in which a plurality of conductive linear bodies are arranged at intervals, and a pair of electrodes in direct contact with the conductive linear bodies, wherein the pair of electrodes each includes two or more metal wires, and the number of metal wires in one of the pair of electrodes is N, and the resistance value of the n-th metal wire counting from the outside of the electrodes in a plan view of the wiring sheet is R. n When the above formula (F1) and the above formula (F2) are satisfied, a wiring sheet is provided in which each of the pair of electrodes satisfies all of the conditions shown in the following formula (F1) and the following formula (F2). R n ≦R n+1 ···(F1) R1 <R N (F2)

[0007] In the wiring sheet according to one aspect of the present invention, the metal wires are preferably gold-plated.

[0008] In the wiring sheet according to one aspect of the present invention, adjacent metal wires preferably do not contact each other.

[0009] In the wiring sheet according to one aspect of the present invention, the distance between adjacent metal wires constituting the electrodes is preferably 0.5 mm or more and 5 mm or less.

[0010] In the wiring sheet according to one aspect of the present invention, the distance between the outermost metal wire and the innermost metal wire among the metal wires constituting the electrode is preferably 3 mm or more and 30 mm or less.

[0011] In the wiring sheet according to one aspect of the present invention, when the resistance value of the pseudo sheet structure is r and the resistance value of the electrode is R, it is preferable that the condition shown in the following formula (F3) be satisfied. r / R<20 (F3)

[0012] In the wiring sheet according to one aspect of the present invention, the metal wires constituting the pair of electrodes are preferably line-symmetrical when viewed from above the wiring sheet.

[0013] According to one aspect of the present invention, a wiring sheet capable of suppressing temperature unevenness within an electrode can be provided. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing a wiring sheet according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing the II-II cross section of FIG. [Figure 3] FIG. 4 is a schematic diagram showing a wiring sheet according to a second embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view showing the IV-IV cross section of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] [First embodiment] The present invention will be described below with reference to the drawings, taking an embodiment as an example. The present invention is not limited to the content of the embodiment. In the drawings, some parts are illustrated enlarged or reduced in size for ease of explanation.

[0016] (wiring sheet) As shown in FIGS. 1 and 2 , the wiring sheet 100 according to this embodiment includes a substrate 1, a pseudo sheet structure 2, a resin layer 3, and a pair of electrodes 4. Specifically, the wiring sheet 100 includes the resin layer 3 laminated on the substrate 1, and the pseudo sheet structure 2 laminated on the resin layer 3. The pseudo sheet structure 2 includes a plurality of conductive linear members 21 arranged at intervals. Each of the pair of electrodes 4 includes two or more metal wires 41. Each of the pair of electrodes 4 is provided with a power supply portion 5.

[0017] In this embodiment, the number of metal wires 41 of one electrode 4 is N, and the resistance value of the n-th metal wire 41 counted from the outside of the electrode 4 in a plan view of the wiring sheet 100 is R n When this is the case, it is necessary to satisfy all the conditions shown in the following formula (F1) and formula (F2). Here, the "nth metal wire 41 counted from the outside of the electrode 4" refers to the metal wire 41 electrically connected to the conductive linear body 21, and refers to the nth metal wire 41 counted from the end side of the conductive linear body 21.

[0018] In this embodiment, it is necessary to satisfy the condition shown in the following formula (F1). R n ≦R n+1 ···(F1)

[0019] If the condition shown in formula (F1) is not satisfied, the temperature unevenness in the electrode cannot be suppressed. In the formula (F1), n ​​is an integer equal to or greater than 1. The upper limit of n is the number N of the metal wires 41. The number N of metal wires 41 is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more. The greater the number of metal wires 41, the more likely temperature unevenness is to occur within the electrode. However, even when there are a large number of metal wires 41, the wiring sheet 100 according to this embodiment can suppress temperature unevenness within the electrode. The upper limit of the number N of metal wires 41 is not particularly limited, but is, for example, 10.

[0020] In this embodiment, it is necessary to satisfy the condition shown in the following formula (F2). R1 <R N (F2)

[0021] If the condition shown in formula (F2) is not satisfied, the temperature unevenness in the electrode cannot be suppressed. In addition, from the viewpoint of further suppressing temperature unevenness within the electrode, R N The value of / R1 is preferably 1.5 or more, more preferably 2 or more, and even more preferably 3 or more.

[0022] The inventors of the present invention believe that the reason why temperature unevenness in the electrode can be suppressed when all the conditions shown in formula (F1) and formula (F2) are satisfied is as follows. That is, when electrode 4 has two or more metal wires 41 made of materials with the same resistance value, current tends to flow more easily through metal wire 41 located on the inside in a plan view of wiring sheet 100, making metal wire 41 more likely to generate heat. As a result, the inventors speculate that when current is passed through wiring sheet 100 to generate heat, temperature unevenness occurs within the electrode. In contrast, when the conditions shown in formula (F1) and formula (F2) are satisfied, the resistance value of metal wires 41 becomes higher toward the inside in a plan view of wiring sheet 100. Furthermore, the current flows less easily through metal wires 41 that are closer to the inside. As a result, heat generated in metal wires 41 that are closer to the inside can be dispersed to metal wires 41 that are closer to the outside. The inventors speculate that this makes it possible to suppress temperature unevenness within the electrode.

[0023] In this embodiment, when the resistance value of the pseudo sheet structure 2 is r and the resistance value of the electrode 4 is R, it is preferable to satisfy the condition shown in the following formula (F3). r / R<20 (F3)

[0024] When the value of r / R is 20 or greater, the resistance of pseudo sheet structure 2, which is the heat-generating part, is sufficiently greater than the resistance of electrode 4. Therefore, in wiring sheet 100, the resistance of electrode 4 can be almost ignored, and problems of temperature unevenness within the electrode tend not to occur. In contrast, as the value of r / R decreases, the problem of temperature unevenness within the electrode becomes more likely to occur, and therefore the significance of using wiring sheet 100 according to this embodiment increases. The resistance values ​​of the electrode 4 and the pseudo sheet structure 2 can be measured using a tester. First, the resistance value of the electrode 4 is measured, and then the resistance value of the pseudo sheet structure 2 to which the electrode 4 is attached is measured. Then, the resistance value of each of the electrode 4 and the pseudo sheet structure 2 is calculated by subtracting the measured value of the electrode 4 from the resistance value of the pseudo sheet structure 2 to which the electrode 4 is attached. Also, if necessary, the electrode 4 can be removed from the wiring sheet 100 and the resistance value can be measured.

[0025] The resistance values ​​of the pseudo sheet structure 2 and the conductive linear body 21, as well as the resistance values ​​of the electrode 4 and the metal wire 41, can be set appropriately using known methods, and can be adjusted, for example, by changing the material, cross-sectional area, length, etc.

[0026] (base material) The substrate 1 can directly or indirectly support the pseudo sheet structure 2. Examples of the substrate 1 include synthetic resin film, paper, metal foil, nonwoven fabric, cloth, and glass film. The substrate 1 is preferably a stretchable substrate. If the substrate 1 is a stretchable substrate, the stretchability of the wiring sheet 100 can be ensured even when the pseudo sheet structure 2 is provided on the substrate 1. As the stretchable substrate, a synthetic resin film, a nonwoven fabric, a cloth, or the like can be used. Examples of synthetic resin films include polyethylene films, polypropylene films, polybutene films, polybutadiene films, polymethylpentene films, polyvinyl chloride films, vinyl chloride copolymer films, polyethylene terephthalate films, polyethylene naphthalate films, polybutylene terephthalate films, polyurethane films, ethylene-vinyl acetate copolymer films, ionomer resin films, ethylene-(meth)acrylic acid copolymer films, ethylene-(meth)acrylic acid ester copolymer films, polystyrene films, polycarbonate films, and polyimide films. Other stretchable substrates include crosslinked films and laminated films of these. Examples of nonwoven fabrics include spunbond nonwoven fabrics, needle-punched nonwoven fabrics, melt-blown nonwoven fabrics, and spunlace nonwoven fabrics. Examples of cloth include woven fabrics and knitted fabrics. The paper, nonwoven fabric, and cloth used as the stretchable substrate are not limited to these. The thickness of the stretchable substrate is not particularly limited, and is preferably 10 μm to 10 mm, more preferably 15 μm to 3 mm, and even more preferably 50 μm to 1.5 mm.

[0027] (pseudo seat structure) The pseudo sheet structure 2 has a structure in which a plurality of conductive linear members 21 are arranged at intervals from one another. That is, the pseudo sheet structure 2 is a structure in which a plurality of conductive linear members 21 are arranged at intervals from one another to form a flat or curved surface. The conductive linear members 21 extend in one direction and have a straight or wavy shape in a plan view of the wiring sheet 100. The pseudo sheet structure 2 has a structure in which a plurality of conductive linear members 21 are arranged in a direction perpendicular to the axial direction of the conductive linear members 21. Preferably, conductive linear members 21 have a wave shape in a plan view of wiring sheet 100. Examples of wave shapes include a sine wave, a rectangular wave, a triangular wave, and a sawtooth wave. If pseudo sheet structure 2 has such a structure, breakage of conductive linear members 21 can be suppressed when wiring sheet 100 is stretched in the axial direction of conductive linear members 21.

[0028] The volume resistivity of the conductive linear body 21 is 1.0×10 -9 Ω m or more 1.0×10 -3 It is preferable that the resistance is Ω·m or less, and 1.0×10 -8 Ω m or more 1.0×10 -4 It is more preferable that the volume resistivity is Ω·m or less. When the volume resistivity of the conductive linear members 21 is in the above range, the surface resistance of the pseudo sheet structure 2 tends to decrease. The volume resistivity of the conductive linear body 21 was measured as follows: Silver paste was applied to both ends of the conductive linear body 21, and the resistance of a portion 40 mm long from each end was measured to determine the resistance value of the conductive linear body 21. Then, the cross-sectional area (unit: m 2 ) is multiplied by the resistance value, and the obtained value is divided by the measured length (0.04 m) to calculate the volume resistivity of the conductive linear body 21.

[0029] The cross-sectional shape of the conductive linear body 21 is not particularly limited and may be polygonal, flat, elliptical, circular, or the like, but is preferably elliptical or circular from the viewpoint of compatibility with the resin layer 3, etc. When the cross section of the conductive linear member 21 is circular, the thickness (diameter) D (see FIG. 2) of the conductive linear member 21 is preferably 5 μm or more and 75 μm or less. From the viewpoints of suppressing an increase in sheet resistance and improving heat generation efficiency and dielectric breakdown resistance when the wiring sheet 100 is used as a heating element, the diameter D of the conductive linear member 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 diameter D described above.

[0030] The diameter D of the conductive linear body 21 is determined by observing the conductive linear body 21 of the pseudo sheet structure 2 using a digital microscope, measuring the diameter of the conductive linear body 21 at five randomly selected locations, and taking the average value.

[0031] The interval L (see FIG. 2) between the conductive linear members 21 is preferably 0.3 mm or more and 50 mm or less, more preferably 0.5 mm or more and 30 mm or less, and even more preferably 0.8 mm or more and 20 mm or less. If the spacing between the conductive linear members 21 is within the above range, the conductive linear members are relatively densely packed, thereby improving the functionality of the wiring sheet 100, such as maintaining a low resistance of the pseudo-sheet structure and making the distribution of temperature rise uniform when the wiring sheet 100 is used as a heating element.

[0032] The interval L between the conductive linear members 21 is determined by observing the conductive linear members 21 of the pseudo sheet structure 2 using a digital microscope and measuring the interval between two adjacent conductive linear members 21. 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 opposing portions of the two conductive linear bodies 21 (see FIG. 2). When the conductive linear bodies 21 are arranged at uneven intervals, the interval L is the average value of the intervals between all adjacent conductive linear bodies 21.

[0033] 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"). Metal wire has high thermal conductivity, high electrical conductivity, easy handling, and versatility, so when a metal wire linear body is used as the conductive linear body 21, the resistance value of the pseudo sheet structure 2 is reduced while the light transmittance is easily improved. Furthermore, when the wiring sheet 100 (pseudo sheet structure 2) is used as a heating element, rapid heat generation is easily achieved. Furthermore, as described above, it is easy to obtain linear bodies with a small diameter. The conductive linear body 21 may be a metal wire linear body, a linear body containing carbon nanotubes, or a linear body in which a thread is coated with a conductive material.

[0034] The metal wire linear body may be a linear body made of a single metal wire, or may be a linear body made of a plurality of twisted metal wires. Examples of metal wires include wires containing metals such as copper, aluminum, tungsten, iron, molybdenum, nickel, titanium, silver, and gold, or alloys containing two or more metals (e.g., steels such as stainless steel and carbon steel, brass, phosphor bronze, zirconium-copper alloys, beryllium copper, iron-nickel, nichrome, nickel-titanium, Kanthal, Hastelloy, and rhenium-tungsten). Metal wires may be plated with gold, tin, zinc, silver, nickel, chromium, nickel-chromium alloys, solder, or the like, or may be surface-coated with a carbon material or polymer, as described below. Wires containing one or more metals selected from tungsten, molybdenum, and alloys containing these metals are particularly preferred from the viewpoint of forming a thin, high-strength, and low-volume resistivity conductive linear body 21. The metal wire may be a metal wire coated with a carbon material. When the metal wire is coated with a carbon material, the metallic luster is reduced, making it easier to make the metal wire less noticeable. Furthermore, when the metal wire is coated with a carbon material, metal corrosion is also suppressed. Examples of carbon materials that can be used to coat 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.

[0035] A linear body containing carbon nanotubes can be obtained, for example, by drawing carbon nanotubes into a sheet from the end of a carbon nanotube forest (a growth body in which multiple carbon nanotubes are grown on a substrate so as to be aligned perpendicular to the substrate; sometimes referred to as an "array"), bundling the drawn carbon nanotube sheets, and then twisting the bundles of carbon nanotubes. In this production method, if no twist is applied during twisting, a ribbon-shaped linear body of carbon nanotubes is obtained, whereas if twist is applied, a thread-shaped linear body is obtained. A ribbon-shaped linear body of carbon nanotubes is a linear body in which the carbon nanotubes do not have a twisted structure. Alternatively, a linear body of carbon nanotubes can be obtained by spinning a dispersion of carbon nanotubes. The production of linear carbon nanotubes by spinning can be performed, for example, by the method disclosed in U.S. Patent Application Publication No. 2013 / 0251619 (JP Patent Publication No. 2012-126635). From the viewpoint of obtaining uniformity in the diameter of the carbon nanotube linear bodies, it is desirable to use thread-like carbon nanotube linear bodies, and from the viewpoint of obtaining highly pure carbon nanotube linear bodies, it is preferable to obtain thread-like carbon nanotube linear bodies by twisting a carbon nanotube sheet. The carbon nanotube linear body may be a linear body formed by weaving two or more carbon nanotube linear bodies together. Furthermore, the carbon nanotube linear body may be a linear body formed by combining carbon nanotubes with other conductive materials (hereinafter also referred to as a "composite linear body").

[0036] Examples of composite linear bodies include: (1) a composite linear body in which, in the process of obtaining a carbon nanotube linear body by drawing carbon nanotubes into a sheet form from the end of a carbon nanotube forest, bundling the drawn carbon nanotube sheet, and then twisting the carbon nanotube bundles, a metal element or a metal alloy is supported on the surface of the carbon nanotube forest, sheet, or bundle, or twisted linear body by vapor deposition, ion plating, sputtering, wet plating, or the like; (2) a composite linear body in which bundles of carbon nanotubes are twisted together with linear bodies of a metal element or a metal alloy, or a composite linear body; and (3) a composite linear body in which linear bodies of a metal element or a metal alloy, or a composite linear body, are braided with linear bodies of a carbon nanotube element or a composite linear body. In the composite linear body of (2), a metal may be supported on the carbon nanotubes when twisting the bundles of carbon nanotubes, as in the composite linear body of (1). Furthermore, the composite linear body of (3) is a composite linear body in which two linear bodies are woven together, but it may also be a composite linear body in which three or more carbon nanotube linear bodies, or linear bodies of a single metal or a metal alloy, or composite linear bodies are woven together, as long as it contains at least one linear body of a single metal or a metal alloy, or composite linear body. Examples of metals for the composite linear body include simple metals such as gold, silver, copper, iron, aluminum, nickel, chromium, tin, and zinc, as well as alloys containing at least one of these simple metals (such as copper-nickel-phosphorus alloys and copper-iron-phosphorus-zinc alloys).

[0037] 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 of metals, conductive polymers, carbon materials, etc. The conductive coating can be formed by plating or vapor deposition, etc. A linear body in which a conductive coating is applied to a thread can improve the conductivity of the linear body while maintaining the flexibility of the thread. In other words, it becomes easier to reduce the resistance of the pseudo sheet structure 2.

[0038] (resin layer) The resin layer 3 is a layer containing resin. The pseudo sheet structure 2 can be supported directly or indirectly by the resin layer 3. The resin layer 3 is preferably a layer containing an adhesive. When the pseudo sheet structure 2 is formed on the resin layer 3, the adhesive makes it easy to attach the conductive linear members 21 to the resin layer 3. The resin layer 3 is preferably stretchable. In this case, the stretchability of the wiring sheet 100 can be ensured.

[0039] The resin layer 3 may be a layer made of a dryable or curable resin. This provides the resin layer 3 with sufficient hardness to protect the pseudo sheet structure 2, and the resin layer 3 also functions as a protective film. Furthermore, the resin layer 3 after curing or drying has impact resistance, and deformation of the resin layer 3 due to impact can be suppressed.

[0040] The resin layer 3 is preferably curable with energy rays such as ultraviolet rays, visible energy rays, infrared rays, and electron beams, since it can be easily cured in a short time. Note that "energy ray curing" also includes heat curing by heating using energy rays.

[0041] The adhesive for the resin layer 3 may be a thermosetting adhesive that hardens when heated, a so-called heat seal type that bonds when heated, or an adhesive that becomes adhesive when moistened. However, for ease of application, it is preferable that the resin layer 3 be energy ray curable. Examples of energy ray curable resins include compounds having at least one polymerizable double bond in the molecule, and acrylate compounds having a (meth)acryloyl group are preferred.

[0042] Examples of the acrylate-based compound include (meth)acrylates containing a chain aliphatic skeleton (trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol 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. acrylates, etc.), alicyclic skeleton-containing (meth)acrylates (dicyclopentanyl di(meth)acrylate, dicyclopentadiene di(meth)acrylate, etc.), polyalkylene glycol (meth)acrylates (polyethylene glycol di(meth)acrylate, etc.), oligoester (meth)acrylates, urethane (meth)acrylate oligomers, epoxy-modified (meth)acrylates, polyether (meth)acrylates other than the above-mentioned polyalkylene glycol (meth)acrylates, and itaconic acid oligomers.

[0043] The weight average molecular weight (Mw) of the energy ray curable resin is preferably 100 to 30,000, and more preferably 300 to 10,000.

[0044] The adhesive composition may contain one or more types of energy ray-curable resins, and when two or more types are contained, the combination and ratio thereof can be selected arbitrarily. Furthermore, the adhesive composition may be combined with a thermoplastic resin described below, and the combination and ratio can be selected arbitrarily.

[0045] The resin layer 3 may be a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive (pressure-sensitive adhesive). The pressure-sensitive adhesive of the pressure-sensitive adhesive layer is not particularly limited. Examples of pressure-sensitive adhesives include acrylic pressure-sensitive adhesives, urethane pressure-sensitive adhesives, rubber pressure-sensitive adhesives, polyester pressure-sensitive adhesives, silicone pressure-sensitive adhesives, and polyvinyl ether pressure-sensitive adhesives. Among these, the pressure-sensitive adhesive is preferably at least one selected from the group consisting of acrylic pressure-sensitive adhesives, urethane pressure-sensitive adhesives, and rubber pressure-sensitive adhesives, and is more preferably an acrylic pressure-sensitive adhesive.

[0046] Examples of acrylic adhesives include polymers containing structural units derived from alkyl (meth)acrylates having a linear alkyl group or a branched alkyl group (i.e., polymers obtained by polymerizing at least alkyl (meth)acrylates), acrylic polymers containing structural units derived from (meth)acrylates having a cyclic structure (i.e., polymers obtained by polymerizing at least (meth)acrylates having a cyclic structure), etc. Here, the term "(meth)acrylate" is used to refer to both "acrylate" and "methacrylate," and the same applies to other similar terms.

[0047] The acrylic copolymer may be crosslinked with a crosslinking agent. Examples of the crosslinking agent include known epoxy crosslinking agents, isocyanate crosslinking agents, aziridine crosslinking agents, and metal chelate crosslinking agents. When the acrylic copolymer is crosslinked, a functional group derived from the monomer component of the acrylic polymer, such as a hydroxyl group or a carboxyl group that reacts with these crosslinking agents, can be introduced into the acrylic copolymer.

[0048] When the resin layer 3 is formed from a pressure-sensitive adhesive, the resin layer 3 may further contain the above-mentioned energy ray-curable resin in addition to the pressure-sensitive adhesive. Furthermore, when an acrylic pressure-sensitive adhesive is used as the pressure-sensitive adhesive, a compound having both a functional group reactive 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 as the energy ray-curable component. The reaction between the functional group of the compound and the functional group derived from the monomer component in the acrylic copolymer makes the side chain of the acrylic copolymer polymerizable by energy ray irradiation. Even when the pressure-sensitive adhesive is not an acrylic pressure-sensitive adhesive, a component whose side chain is energy ray-polymerizable may also be used as a polymer component other than the acrylic polymer.

[0049] The thermosetting resin used in the resin layer 3 is not particularly limited, and specific examples include epoxy resins, phenolic resins, melamine resins, urea resins, polyester resins, urethane resins, acrylic resins, benzoxazine resins, phenoxy resins, amine compounds, and acid anhydride compounds. These can be used alone or in combination of two or more. Among these, epoxy resins, phenolic resins, melamine resins, urea resins, amine compounds, and acid anhydride compounds are preferred from the viewpoint of suitability for curing using an imidazole curing catalyst. In particular, epoxy resins, phenolic resins, mixtures thereof, or mixtures of epoxy resins with at least one selected from the group consisting of phenolic resins, melamine resins, urea resins, amine compounds, and acid anhydride compounds are preferred from the viewpoint of exhibiting excellent curability.

[0050] The moisture-curable resin used in the resin layer 3 is not particularly limited, and examples thereof include urethane resins and modified silicone resins, which are resins that generate isocyanate groups when exposed to moisture.

[0051] When an energy ray curable resin or a thermosetting resin is used, it is preferable to use a photopolymerization initiator, a thermal polymerization initiator, etc. By using a photopolymerization initiator, a thermal polymerization initiator, etc., a crosslinked structure is formed, making it possible to more firmly protect the pseudo sheet structure 2.

[0052] Examples of the photopolymerization initiator include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, 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.

[0053] Examples of the thermal polymerization initiator include hydrogen peroxide, peroxodisulfates (ammonium peroxodisulfate, sodium peroxodisulfate, potassium peroxodisulfate, etc.), azo compounds (2,2'-azobis(2-amidinopropane) dihydrochloride, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobisisobutyronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), etc.), and organic peroxides (benzoyl peroxide, lauroyl peroxide, peracetic acid, persuccinic acid, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, etc.).

[0054] These polymerization initiators can be used alone or in combination of two or more. When these polymerization initiators are used to form a crosslinked structure, the amount used is preferably 0.1 parts 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, relative to 100 parts by mass of the energy ray-curable resin or the thermosetting resin.

[0055] The resin layer 3 may not be curable, and may be a layer made of, for example, a thermoplastic resin composition. The thermoplastic resin layer can be softened by adding a solvent to the thermoplastic resin composition. This makes it easier to attach the conductive linear members 21 to the resin layer 3 when forming the pseudo-sheet structure 2 on the resin layer 3. On the other hand, the thermoplastic resin layer can be dried and solidified by volatilizing the solvent in the thermoplastic resin composition.

[0056] 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-based solvents, ketone-based solvents, ester-based solvents, ether-based solvents, hydrocarbon-based solvents, alkyl halide-based solvents, and water.

[0057] The resin layer 3 may contain an inorganic filler. By containing an inorganic filler, the hardness of the cured resin layer 3 can be further improved. In addition, the thermal conductivity of the resin layer 3 is improved.

[0058] Examples of inorganic fillers include inorganic powders (e.g., powders of silica, alumina, talc, calcium carbonate, titanium white, red iron oxide, silicon carbide, metals, and boron nitride), beads obtained by spheroidizing inorganic powders, single-crystal fibers, and glass fibers. Among these, silica filler and alumina filler are preferred as inorganic fillers. One type of inorganic filler may be used alone, or two or more types may be used in combination.

[0059] The resin layer 3 may contain other components, such as well-known additives such as organic solvents, flame retardants, tackifiers, ultraviolet absorbers, antioxidants, preservatives, antifungal agents, plasticizers, antifoaming agents, and wettability adjusters.

[0060] The thickness of resin layer 3 is determined appropriately depending on the application of wiring sheet 100. For example, from the viewpoint of adhesiveness, the thickness of 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.

[0061] (electrode) The electrodes 4 are used to supply current to the conductive linear body 21. The electrodes 4 are in direct contact with the conductive linear body 21. The electrodes 4 are disposed so as to be electrically connected to both ends of the conductive linear body 21. The electrode 4 includes two or more metal wires 41. As shown in FIG. 1 , the number of metal wires 41 may be four. In addition, the number of metal wires 41 used in one electrode 4 of a pair of electrodes 4 may be different from the number of metal wires 41 used in the other electrode 4. However, from the viewpoint of suppressing temperature unevenness, it is preferable that the number of metal wires 41 used in one electrode 4 is the same as the number of metal wires 41 used in the other electrode 4. From the same viewpoint, it is preferable that the metal wires 41 constituting the pair of electrodes 4 are line-symmetrical when viewed from above the wiring sheet 100. Furthermore, metal wires 41 preferably have a wave shape in a plan view of wiring sheet 100. Examples of wave shapes include a sine wave, a rectangular wave, a triangular wave, and a sawtooth wave. If electrode 4 has such a structure, breakage of electrode 4 can be suppressed when wiring sheet 100 is stretched in the axial direction of electrode 4.

[0062] Examples of metals for the metal wire 41 include copper, aluminum, tungsten, iron, molybdenum, nickel, titanium, silver, and gold, as well as alloys containing two or more metals (e.g., stainless steel, carbon steel, and other steels, brass, phosphor bronze, zirconium-copper alloy, beryllium copper, iron-nickel, nichrome, nickel-titanium, Kanthal, Hastelloy, and rhenium-tungsten). The metal wire 41 may also be plated with gold, tin, zinc, silver, nickel, chromium, a nickel-chromium alloy, solder, or the like. However, the metal wire 41 is preferably gold-plated. In this case, contact resistance between the metal wire 41 and the conductive linear body 21 can be reduced, thereby suppressing heat generation in the electrode 4.

[0063] The cross-sectional shape of the metal wire 41 is not particularly limited and may be polygonal, flat, elliptical, circular, or the like, but is preferably elliptical or circular. When the cross section of the metal wire 41 is circular, the thickness (diameter) of the metal wire 41 is preferably 5 μm or more and 1000 μm or less, more preferably 20 μm or more and 500 μm or less, and even more preferably 50 μm or more and 300 μm or less. When the cross section of the metal wire 41 is elliptical, it is preferable that the major axis is in the same range as the diameter described above.

[0064] Adjacent metal wires 41 may be in contact with each other, but preferably are not in contact with each other. Here, "adjacent metal wires 41 are in contact with each other" means that adjacent metal wires 41 are in direct contact with each other. "adjacent metal wires 41 are not in contact with each other" means that adjacent metal wires 41 are not in direct contact with each other, and in this case, adjacent metal wires 41 may be electrically connected to each other. For example, if all adjacent metal wires 41 are in contact with each other, it is the same as a single piece of metal foil, and the problem of temperature unevenness within the electrode tends to be less likely to occur. In contrast, if adjacent metal wires 41 are not in contact with each other, the problem of temperature unevenness within the electrode is more likely to occur, and therefore the significance of using wiring sheet 100 according to this embodiment is enhanced.

[0065] The distance between adjacent metal wires 41 is preferably 0.5 mm to 5 mm, and more preferably 1 mm to 4 mm. If the distance between adjacent metal wires 41 is equal to or greater than the lower limit, electrical conduction between adjacent metal wires 41 can be reliably prevented. If the distance between adjacent metal wires 41 is equal to or less than the upper limit, it is preferable because it is easier to adjust the number of metal wires 41.

[0066] Of the metal wires 41 constituting the electrode 4, the distance between the outermost metal wire 41 and the innermost metal wire 41 is preferably 3 mm or more and 30 mm or less, and more preferably 5 mm or more and 20 mm or less. If this distance is within the above range, it is easy to adjust the number of metal wires 41, etc.

[0067] (Power supply unit) The power supply portion 5 is a portion that applies a voltage to the wiring sheet 100. If the electrode 4 is exposed and can be electrically connected, any portion of the electrode 4 can be the power supply portion 5. However, since the electrode 4 includes two or more metal wires 41, the power supply portion 5 must be electrically connected to all of the metal wires 41. Furthermore, if the electrode 4 is covered with an insulating material to prevent short circuits, etc., the portion where part of the insulating material has been removed can be the power supply portion 5. 1, a power supply unit 5 may be provided separately to facilitate connection of a power source (not shown) to the electrode 4. In this case, the material of the power supply unit 5 may be the same as the material of the electrode 4.

[0068] (Method of manufacturing wiring sheet) There are no particular limitations on the method for manufacturing interconnect sheet 100 according to this embodiment. Interconnect sheet 100 can be manufactured, for example, by the following steps. First, a composition for forming the resin layer 3 is applied to the substrate 1 to form a coating film. The coating film is then dried to create the resin layer 3. Next, conductive linear bodies 21 are arranged and placed on the resin layer 3 to form the pseudo-sheet structure 2. For example, with the resin layer 3 with the substrate 1 attached thereto placed on the outer circumferential surface of a drum member, the drum member is rotated while the conductive linear bodies 21 are spirally wound around the resin layer 3. The spirally wound bundle of conductive linear bodies 21 is then cut along the axial direction of the drum member. This forms the pseudo-sheet structure 2 and places it on the resin layer 3. The resin layer 3 with the substrate 1 on which the pseudo-sheet structure 2 is formed is then removed from the drum member to obtain a sheet-like conductive member. According to this method, for example, while rotating the drum member, the spacing L between adjacent conductive linear bodies 21 in the pseudo-sheet structure 2 can be easily adjusted by moving the feeding portion of the conductive linear bodies 21 in a direction parallel to the axis of the drum member. Next, a pair of two or more metal wires 41 that constitute the electrode 4 is prepared, and the two or more metal wires 41 are attached to each side of the pair of both ends of the conductive linear body 21 in the pseudo-sheet structure 2 of the sheet-like conductive member, and then a power supply part 5 is provided to produce the wiring sheet 100.

[0069] (Operation and effect of the first embodiment) According to this embodiment, the following effects can be achieved. (1) According to this embodiment, by satisfying the conditions shown in formulas (F1) and (F2), the resistance value of the metal wires 41 becomes higher as the metal wires 41 are closer to the inside in a plan view of the wiring sheet 100. As a result, the current flows less easily through the metal wires 41 closer to the inside. As a result, heat generated in the metal wires 41 closer to the inside can be dispersed to the metal wires 41 closer to the outside. In this way, temperature unevenness within the electrode can be suppressed.

[0070] [Second embodiment] Next, a second embodiment of the present invention will be described with reference to the drawings. The present invention is not limited to the content of this embodiment. Note that in the drawings, some parts are illustrated enlarged or reduced in size for ease of explanation. The second embodiment differs from the first embodiment in that the resistance value of the metal wire 41 is adjusted by changing the cross-sectional area of ​​the metal wire 41 . In the following description, differences from the first embodiment will be mainly described, and overlapping descriptions will be omitted or simplified. The same components as those in the first embodiment will be assigned the same reference numerals, and descriptions thereof will be omitted or simplified.

[0071] As shown in Figures 3 and 4, wiring sheet 100A according to this embodiment includes a substrate 1, a pseudo sheet structure 2, a resin layer 3, and a pair of electrodes 4. Electrode 4 includes four metal wires 41. Each electrode 4 is provided with a power supply portion 5. The four metal wires 41 each have a different cross-sectional area. The material of the metal wires 41 is the same. The cross-sectional area of ​​the metal wires 41 decreases from the outside to the inside of the electrode 4. As a result, the resistance value of the first metal wire 41 counting from the outside of the electrode 4 is R n In this case, the relationship is as follows: R1 <R2<R3<R4 That is, all the conditions shown in the formula (F1) and the formula (F2) are satisfied.

[0072] (Operation and effect of the second embodiment) According to this embodiment, in addition to the effect (1) of the first embodiment, the following effect (2) can be achieved. (2) In this embodiment, the resistance value of the metal wire 41 that constitutes the electrode 4 can be changed without changing the material of the metal wire 41.

[0073] [Modification of the embodiment] The present invention is not limited to the above-described embodiment, and includes modifications and improvements within the scope of achieving the object of the present invention. For example, in the above-described embodiment, interconnect sheet 100 includes substrate 1, but is not limited to this. For example, interconnect sheet 100 does not necessarily have to include substrate 1. In such a case, interconnect sheet 100 can be used by being attached to an adherend by resin layer 3. In the above-described embodiment, wiring sheet 100 includes resin layer 3, but is not limited to this. For example, wiring sheet 100 may not include resin layer 3. In such a case, a knitted fabric may be used as substrate 1, and conductive linear members 21 may be woven into substrate 1 to form pseudo sheet structure 2. [Example]

[0074] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0075] [Example 1] An adhesive sheet was prepared by applying a 20 μm thick acrylic adhesive ("PK" manufactured by Lintec Corporation) to a 50 μm thick PET film. Gold-plated tungsten wire (25 μm diameter, "Au(0.1)-TWG" manufactured by Tokusai Corporation) was used as the conductive linear member. The adhesive sheet was then wrapped around a rubber drum member with the pressure-sensitive adhesive layer facing outward, ensuring no wrinkles. Both ends of the adhesive sheet in the circumferential direction were secured with double-sided tape. The conductive linear member wound around the bobbin was attached to the surface of the pressure-sensitive adhesive layer of the adhesive sheet located near the end of the drum member. The wire was then unwound and wound around the drum member. The drum member was gradually moved in a direction parallel to the drum axis, so that the conductive linear member was wound around the drum member in a spiral at equal intervals. Thirty conductive linear members were arranged at equal intervals of 10 mm. Next, the following four metal wires were prepared as one electrode of a pair of electrodes 4. Next, the four metal wires were placed on both ends of the conductive linear body, spaced 2.5 mm apart, in a direction perpendicular to the direction of extension of the conductive linear body, so that the distance between the electrodes was 200 mm. The other electrode was then attached in the same manner to form a pair of electrodes. A 50 μm-thick PET film was then attached to the adhesive surface of the electrode-attached film on which the conductive linear body was placed, to produce a sheet-like heater. Note that the two power supply points used for power supply were located on opposite sides of the sheet-like heater. (4 metal wires) Metal wire type: Gold-plated copper wire (Tokusai "C1100-H AuP") Diameter of the first metal wire counting from the outside: 200 μm Diameter of the second metal wire counting from the outside: 150 μm Diameter of the third metal wire counting from the outside: 130 μm Diameter of the fourth metal wire counting from the outside: 100 μm

[0076] [Comparative Example 1] A sheet-type heater was produced in the same manner as in Example 1, except that the four metal wires were changed as follows. (4 metal wires) Metal wire type: Gold-plated copper wire (Tokusai "C1100-H AuP") Diameter of the first metal wire counting from the outside: 150 μm Diameter of the second metal wire counting from the outside: 150 μm Diameter of the third metal wire counting from the outside: 150 μm Diameter of the fourth metal wire counting from the outside: 150 μm

[0077] Comparative Example 2 A sheet-type heater was produced in the same manner as in Example 1, except that the four metal wires were changed as follows. (4 metal wires) Metal wire type: Gold-plated copper wire (Tokusai "C1100-H AuP") Diameter of the first metal wire counting from the outside: 100 μm Diameter of the second metal wire counting from the outside: 130 μm Diameter of the third metal wire counting from the outside: 150 μm Diameter of the fourth metal wire counting from the outside: 200 μm

[0078] [Resistance of the nth metal wire counting from the outside of the electrode] The metal wires used in the examples and comparative examples were cut to lengths of 30 cm. Resistance values ​​were measured using a four-terminal method with a resistance meter ("RM3545-02" manufactured by Hioki E.E. Corporation), and the resistance value per unit length (30 cm) was estimated. The results are shown in Table 1.

[0079] [Evaluation of electrode temperature difference] After a current of 3.5 A was passed through the sheet heater to generate heat, the temperature distribution of the electrodes (four metal wires) was measured using a thermographic camera (FLIR C2, manufactured by FLIR) from a position 150 mm from the surface of the sheet heater. The emissivity was set to 0.95 during this measurement. The difference between the maximum and minimum temperatures at the electrode was taken as the temperature difference (unit: °C). The smaller this temperature difference, the more suppressed the temperature unevenness within the electrode. The results are shown in Table 1.

[0080] [Table 1]

[0081] From the results shown in Table 1, the resistance value R of the nth metal wire counting from the outside of the electrode n However, it was confirmed that when the conditions shown in formula (F1) and formula (F2) are satisfied (Example 1), temperature unevenness within the electrode can be suppressed compared to when either of the conditions shown in formula (F1) and formula (F2) is not satisfied (Comparative Examples 1 and 2). [Explanation of symbols]

[0082] 1...substrate, 2...pseudo sheet structure, 21...conductive linear body, 3...resin layer, 4...electrode, 41...metal wire, 5...power supply part, 100,100A...wiring sheet.

Claims

1. A wiring sheet comprising a pseudo-sheet structure in which a plurality of conductive linear bodies are arranged at intervals, and a pair of electrodes in direct contact with the conductive linear bodies, Each of the pair of electrodes includes two or more metal wires; The number of metal wires of one of the pair of electrodes is N, and the resistance value of the n-th metal wire counted from the outside of the electrode in a plan view of the wiring sheet is R ｎ When the above formula (F1) and the above formula (F2) are satisfied, each of the pair of electrodes satisfies all of the conditions shown in the following formula (F1) and the following formula (F2): Wiring sheet. R ｎ ≦R ｎ＋１ ・・・(F1) R １ <R Ｎ ・・・(F2)

2. The wiring sheet according to claim 1 , The metal wire is gold plated. Wiring sheet.

3. The wiring sheet according to claim 1 or 2, Adjacent metal wires are not in contact with each other. Wiring sheet.

4. The wiring sheet according to any one of claims 1 to 3, Among the metal wires constituting the electrode, the interval between adjacent metal wires is 0.5 mm or more and 5 mm or less. Wiring sheet.

5. The wiring sheet according to any one of claims 1 to 4, Among the metal wires constituting the electrode, the distance between the outermost metal wire and the innermost metal wire is 3 mm or more and 30 mm or less. Wiring sheet.

6. The wiring sheet according to any one of claims 1 to 5, When the resistance value of the pseudo sheet structure is r and the resistance value of the electrode is R, the condition shown in the following formula (F3) is satisfied: Wiring sheet. r / R<20...(F3)

7. The wiring sheet according to any one of claims 1 to 6, The metal wires constituting the pair of electrodes are line-symmetrical in a plan view of the wiring sheet. Wiring sheet.

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