Wiring sheet and method for manufacturing the same

Abstract

To provide a wiring sheet capable of suppressing a change in the resistance value of a wiring sheet.SOLUTION: A wiring sheet 100 includes a wiring body 2 having a conductive linear body 21 and a pair of electrodes 4 in direct contact with the conductive linear body 21, and the electrode 4 has, in a cross-sectional view, a base portion 41 and a step portion 42 provided on the base portion 41 and narrower than the base portion 41.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a wiring sheet and a method for manufacturing the same. [Background technology]

[0002] A wiring sheet having a pseudo-sheet structure in which a plurality of conductors are arranged at intervals is known. This wiring sheet can be used, for example, as a material for heat-generating textiles, a member for generating heat in various articles, and a heating element in a heat-generating device. As an example of a sheet used as a heating element, Patent Document 1 discloses a surface heat source including a heating element containing a plurality of carbon nanotubes and at least two electrodes electrically connected to the heating element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-034059 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, it has been found that when the wiring sheet described in Patent Document 1 is used in a humid and hot environment, the resistance value of the wiring sheet may increase.

[0005] An object of the present invention is to provide a wiring sheet capable of suppressing changes in the resistance value of the wiring sheet, and a method for manufacturing the wiring sheet. [Means for solving the problem]

[0006] [1] A wiring body having a conductive linear body; A pair of electrodes in direct contact with the conductive linear body; Equipped with The electrode has, in a cross-sectional view, a base portion and a step portion provided on the base portion and having a narrower width than the base portion. Wiring sheet.

[0007] [2] The wiring sheet according to [1], The Young's modulus of the electrode is 100×10 9 Pa or less, Wiring sheet.

[0008] [3] The wiring sheet according to [1] or [2], The maximum thickness of the electrode is 40 μm or less. Wiring sheet.

[0009] [4] The wiring sheet according to any one of [1] to [3], The maximum width of the electrode is 1 mm or more and 10 mm or less. Wiring sheet.

[0010] [5] The wiring sheet according to any one of [1] to [4], Further, a resin layer is provided to directly or indirectly support the wiring body. Wiring sheet.

[0011] [6] The wiring sheet according to any one of [1] to [5], The wiring body is a plurality of the conductive linear bodies arranged at intervals. Wiring sheet.

[0012] [7] A method for manufacturing a wiring sheet including a wiring body having a conductive linear body and a pair of electrodes in direct contact with the conductive linear body, comprising: applying a conductive paste to form a base portion; a step of applying a conductive paste onto the base portion so as to have a width narrower than that of the base portion to form a step portion; Equipped with A method for manufacturing a wiring sheet. Effect of the Invention

[0013] Advantageous Effects of Invention According to one aspect of the present invention, it is possible to provide an interconnect sheet capable of suppressing changes in the resistance value of the interconnect sheet, and a method for manufacturing the interconnect sheet. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing a wiring sheet according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing the II-II cross section of FIG. [Diagram 3] FIG. 2 is a cross-sectional view showing the cross section III-III of FIG. [Figure 4] FIG. 4 is a cross-sectional view showing a modified embodiment of the electrode according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [Embodiment] Hereinafter, the present invention will be described with reference to the drawings, taking an embodiment as an example. The present invention is not limited to the contents 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, wiring sheet 100 according to this embodiment includes a substrate 1, a wiring body 2, a resin layer 3, and a pair of electrodes 4. The wiring body 2 includes a conductive linear body 21. The wiring body 2 preferably has a structure in which a plurality of conductive linear bodies 21 are arranged at intervals from one another. The resin layer 3 supports the wiring body 2 directly or indirectly. The electrode 4 is in direct contact with the conductive linear body 21. In a cross-sectional view, the electrode 4 has a base portion 41 and a step portion 42 provided on the base portion 41. A width W2 of the step portion 42 is narrower than a width W1 of the base portion 41. A part of the electrode 4 is not covered with the resin layer 3. This part allows electrical connection between the pair of electrodes 4 and a power source (not shown).

[0017] The present inventors surmise that the reason why interconnect sheet 100 according to this embodiment can suppress changes in the resistance value of the interconnect sheet is as follows. That is, it is presumed that the change in resistance value of the wiring sheet 100 is related to the contact state between the conductive linear body 21 and the electrode 4 when the conductive linear body 21 is crimped to the electrode 4. In addition, in a cross-sectional view, the more edges the electrode 4 has, the more firmly the conductive linear body 21 and the electrode 4 are fixed to each other. If the electrode 4 only has the base portion 41, the number of edges of the electrode 4 would be two. In contrast, the electrode 4 in this embodiment has a step portion 42 consisting of a second step portion 421 with two edges and a third step portion 422 with two edges on the base portion 41 with two edges, and the number of edges of the electrode 4 is six. Thus, the inventors presume that if the number of edges of the electrode 4 is three or more, the change in resistance value is small even when left in a humid and hot environment.

[0018] (base material) The substrate 1 can directly or indirectly support the wiring body 2. The substrate 1 is not necessarily required. The substrate 1 is a member that is provided as necessary. Examples of the material of the substrate 1 include resin, paper, metal, nonwoven fabric, cloth, and glass. Among these, from the viewpoint of strength or handling, resin or glass is preferable. Examples of the resin used for the substrate 1 include polyethylene, polypropylene, polystyrene, polycarbonate, and polyacetal.

[0019] Substrate 1 may or may not contain a colorant. The colorant allows the transmittance of visible light and near infrared light in wiring sheet 100 to be adjusted within a desired range.

[0020] The thickness of the substrate 1 is preferably 0.05 mm or more, more preferably 0.25 mm or more, even more preferably 0.5 mm or more, even more preferably 1.0 mm or more, and particularly preferably 1.5 mm or more. The thickness of the substrate 1 is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less. By having the thickness of the substrate 1 in the range of 0.05 mm or more and 10 mm or less, excellent strength and the like can be obtained.

[0021] (Wiring body) The wiring body 2 includes a conductive linear body 21. The wiring body 2 preferably has a structure in which a plurality of conductive linear bodies 21 are arranged at intervals from one another. Furthermore, when the wiring body 2 has a structure in which a plurality of conductive linear bodies 21 are arranged at intervals from one another, it is preferable that the plurality of conductive linear bodies 21 are arranged in a direction intersecting the axial direction of the conductive linear bodies 21.

[0022] The conductive linear body 21 may be linear or wavy in plan view of the wiring sheet 100. Examples of the wave shape include a sine wave, a rectangular wave, a triangular wave, and a sawtooth wave. For example, if the wiring body 2 has such a structure, breakage of the conductive linear body 21 can be suppressed when the wiring sheet 100 is stretched in the axial direction of the conductive linear body 21.

[0023] The volume resistivity of the conductive linear body 21 is 1.0×10 -9 It is preferable that the resistance is Ω·m or more, and 3.0×10 -9 More preferably, it is 1.0×10 -8 The volume resistivity of the conductive linear body 21 is preferably 1.0×10 -3 It is preferable that the resistance is Ω·m or less, and 1.0×10 -4 More preferably, it is 5.0×10 -5 It is more preferable that the volume resistivity is Ω·m or less. When the volume resistivity of the conductive linear body 21 is in the above range, the surface resistance of the wiring body 2 tends to decrease. The volume resistivity of the conductive linear body 21 was measured as follows. Silver paste was applied to the end of the conductive linear body 21 and a portion 40 mm from the end, and the resistance of the end and a portion 40 mm from the end was measured. 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.

[0024] The cross-sectional shape of the conductive linear body 21 is not particularly limited and may be polygonal, flat, elliptical, circular, etc. From the viewpoint of compatibility with the resin layer 3, etc., the cross-sectional shape of the conductive linear body 21 is preferably elliptical or circular.

[0025] When the cross section of the conductive linear member 21 is circular, the diameter D (see FIG. 2) of the conductive linear member 21 is preferably 3 μm or more and 200 μm or less. From the viewpoints of suppressing an increase in sheet resistance and improving the heat generation efficiency and dielectric breakdown resistance characteristics of the wiring sheet 100, the diameter D of the conductive linear member 21 is more preferably 4 μm or more, and even more preferably 5 μm or more. The diameter D of the conductive linear member 21 is more preferably 150 μm or less, even more preferably 100 μm or less, particularly preferably 50 μm or less, and extremely preferably 20 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.

[0026] The diameter D of the conductive linear body 21 is determined by observing the conductive linear body 21 using a digital microscope, measuring the diameter of the conductive linear body 21 at five randomly selected points, and averaging the measured values.

[0027] When the wiring body 2 has a structure in which a plurality of conductive linear bodies 21 are arranged at intervals from one another, the interval L (see FIG. 2) between the conductive linear bodies 21 is preferably 0.3 mm or more, more preferably 0.5 mm or more, even more preferably 0.8 mm or more, and particularly preferably 1.5 mm or more. Moreover, the interval L between the conductive linear bodies 21 is preferably 50 mm or less, more preferably 30 mm or less, even more preferably 20 mm or less, and particularly preferably 5 mm or less. If the spacing between conductive linear bodies 21 is within the above range, the conductive linear bodies are relatively densely packed, which improves the function of wiring sheet 100, such as maintaining the resistance of wiring body 2 low.

[0028] The interval L between the conductive linear bodies 21 is measured by, for example, observing the conductive linear bodies 21 of the wiring body 2 using a digital microscope and measuring the interval between two adjacent conductive linear bodies 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.

[0029] The conductive linear body 21 may be produced by any method, such as etching, screen printing, or inkjet printing, but may be a linear body including a metal wire (hereinafter also referred to as a "metal wire linear body"). Metal wires have high thermal conductivity, high electrical conductivity, and high handling properties. The metal wire linear body can greatly reduce resistance, and even if the diameter of the metal wire linear body is extremely small, it can pass a current required for heating the wiring sheet 100. This makes it possible to make the conductive linear body 21 less visible. That is, when a metal wire linear body is used as the conductive linear body 21, the resistance value of the wiring body 2 can be reduced while the light transmittance can be improved. In addition, the wiring sheet 100 can easily generate heat quickly. Furthermore, as described above, a linear body having a small diameter can be easily obtained. In addition to a metal wire, examples of the conductive linear body 21 include a linear body containing a carbon nanotube and a linear body in which a thread is provided with a conductive coating.

[0030] 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 the metal wire include wires containing metals such as copper, aluminum, tungsten, iron, molybdenum, nickel, titanium, silver, and gold, or alloys containing two or more metals such as stainless steel, carbon steel, brass, phosphor bronze, zirconium copper alloy, beryllium copper, iron nickel, nichrome, nickel titanium, Kanthal, Hastelloy, and tungsten rhenium. The metal wire may be plated with gold, tin, zinc, silver, nickel, chromium, nickel chromium alloy, silver sulfide, or solder, or may be coated with a carbon material or polymer, which will be described later. In particular, wires containing one or more metals selected from tungsten and molybdenum, and alloys containing these metals, are preferred from the viewpoint of low volume resistivity. 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, and the presence of the metal wire can be easily made less noticeable. In addition, when the metal wire is coated with a carbon material, metal corrosion is also suppressed. Examples of the carbon material that coats the metal wire include amorphous carbon such as carbon black, activated carbon, hard carbon, soft carbon, mesoporous carbon, and carbon fiber; graphite, fullerene, graphene, and carbon nanotubes.

[0031] The conductive linear body 21 may be a linear body having a conductive coating applied to the thread. Examples of the thread include threads spun from resins such as nylon or polyester. Examples of the thread include threads of metal fibers, carbon fibers, or ion-conductive polymer fibers. Examples of the conductive coating include coatings of metals, conductive polymers, or carbon materials. The conductive coating can be formed by plating, vapor deposition, or the like. A linear body having a conductive coating applied to the 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 wiring body 2.

[0032] (Resin layer) The resin layer 3 directly or indirectly supports the wiring body 2. The resin layer 3 is not necessarily provided. The resin layer 3 is a member that is provided as necessary. The resin layer 3 can stabilize the resistance value of the wiring body 2. In other words, the resin layer 3 can fix the conductive linear body 21, stabilize the contact between the conductive linear body 21 and the electrode 4, and make it difficult for an increase in the resistance value to occur.

[0033] The thickness of the resin layer 3 is not particularly limited. The thickness of the resin layer 3 may be equal to or greater than the diameter D of the conductive linear body 21, or may be less than the diameter D of the conductive linear body 21. If the thickness of the resin layer 3 is equal to or greater than the diameter D of the conductive linear body 21, the wiring body 2 can be included in the resin layer 3. If the thickness of the resin layer 3 is less than the diameter D of the conductive linear body 21, the wiring body 2 is exposed from the resin layer 3. In addition, when the wiring body 2 is exposed from the resin layer 3, the wiring body 2 may be exposed on the side of the substrate 1 or on the opposite side of the substrate 1. The thickness of the resin layer 3 is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. The thickness of the resin layer 3 is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less.

[0034] From the viewpoint of increasing the storage modulus, the resin layer 3 is preferably a layer made of a cured product of a curable adhesive. Examples of the curable adhesive include a thermosetting adhesive that is cured by heat, and an energy ray curable adhesive. Examples of the energy ray include ultraviolet rays, visible energy rays, infrared rays, and electron beams. Note that "energy ray curing" also includes heat curing by heating using energy rays.

[0035] The thermosetting adhesive preferably contains a thermosetting resin. The thermosetting resin is not particularly limited, and specifically includes epoxy resin, phenol resin, melamine resin, urea resin, polyester resin, urethane resin, acrylic resin, benzoxazine resin, phenoxy resin, amine-based compound, and acid anhydride-based compound. These can be used alone or in combination of two or more. Among these, from the viewpoint of suitability for curing using an imidazole-based curing catalyst, it is preferable to use epoxy resin, phenol resin, melamine resin, urea resin, amine-based compound, and acid anhydride-based compound, and particularly from the viewpoint of showing excellent curing properties, it is preferable to use epoxy resin, phenol resin, a mixture thereof, or a mixture of epoxy resin and at least one selected from the group consisting of phenol resin, melamine resin, urea resin, amine-based compound, and acid anhydride-based compound, and it is preferable to use epoxy resin.

[0036] As the epoxy resin, a cyclic one such as an aromatic epoxy resin or an alicyclic epoxy resin is preferable from the viewpoint of increasing the storage modulus of the resin layer 3. An epoxy resin having a flexible segment such as an oxyalkylene chain tends to decrease the storage modulus of the resin layer 3.

[0037] The energy ray curable adhesive preferably contains an energy ray curable resin. Examples of the energy ray curable resin include a compound having at least one polymerizable double bond in the molecule, and an acrylate compound having a (meth)acryloyl group is preferable.

[0038] Examples of the acrylate compounds include dicyclopentadiene diacrylate, 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. acrylate and other linear aliphatic skeleton-containing (meth)acrylates; dicyclopentanyl di(meth)acrylate and other cyclic aliphatic skeleton-containing (meth)acrylates; polyethylene glycol di(meth)acrylate and other polyalkylene glycol (meth)acrylates; oligoester (meth)acrylates, urethane (meth)acrylate oligomers, epoxy-modified (meth)acrylates, polyether (meth)acrylates other than polyalkylene glycol (meth)acrylates, and itaconic acid oligomers.

[0039] The weight average molecular weight (Mw) of the energy ray curable resin is preferably 100 or more, and more preferably 300 or more. Moreover, this weight average molecular weight is preferably 30,000 or less, and more preferably 10,000 or less. In this specification, the weight average molecular weight is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0040] The adhesive may contain one type of energy ray curable resin or two or more types. When the adhesive contains two or more types of energy ray curable resins, the combination and ratio thereof can be selected arbitrarily.

[0041] 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., the polymerization reaction of the curable resin can be easily initiated, and the curing reaction can be easily controlled.

[0042] Examples of the photopolymerization initiator include photoradical polymerization initiators such as 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.

[0043] In addition to the photoradical polymerization initiator, the photocationic polymerization initiator can be used. The photocationic polymerization initiator is a compound that generates cationic species when irradiated with energy rays and initiates the curing reaction of a cationic curable compound, and is composed of a cationic moiety that absorbs energy rays and an anionic moiety that serves as an acid generating source.

[0044] Examples of the photocationic polymerization initiator include sulfonium salt compounds, iodonium salt compounds, phosphonium salt compounds, ammonium salt compounds, antimony salt compounds, diazonium salt compounds, selenium salt compounds, oxonium salt compounds, bromine salt compounds, etc. Among these, from the viewpoints of excellent compatibility and excellent storage stability of the resulting adhesive, sulfonium salt compounds are preferred, and aromatic sulfonium salt compounds having an aromatic group are more preferred.

[0045] Examples of the sulfonium salt compounds include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, and triphenylsulfonium tetrakis(pentafluorophenyl)borate.

[0046] Examples of iodonium salt compounds include diphenyliodonium tetrakis(pentafluorophenyl)borate, diphenyliodonium hexafluorophosphate, and (tricumyl)iodonium tetrakis(pentafluorophenyl)borate.

[0047] Examples of the phosphonium salt compounds include tri-n-butyl(2,5-dihydroxyphenyl)phosphonium bromide and hexadecyltributylphosphonium chloride.

[0048] Examples of the ammonium salt compound include benzyltrimethylammonium chloride, phenyltributylammonium chloride, and benzyltrimethylammonium bromide.

[0049] Examples of antimonate compounds include triphenylsulfonium hexafluoroantimonate, p-(phenylthio)phenyldiphenylsulfonium hexafluoroantimonate, and diaryliodonium hexafluoroantimonate.

[0050] Examples of the thermal polymerization initiator include peroxodisulfates such as hydrogen peroxide, 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 thermal radical polymerization initiators such as organic peroxides such as benzoyl peroxide, lauroyl peroxide, peracetic acid, persuccinic acid, di-t-butyl peroxide, t-butyl hydroperoxide, and cumene hydroperoxide.

[0051] In addition to the above-mentioned thermal radical polymerization initiator, the thermal cationic polymerization initiator can be used as the thermal polymerization initiator. The thermal cationic polymerization initiator is a compound that can generate cationic species that initiate polymerization by heating. The thermal cationic polymerization initiator can be a sulfonium salt, a quaternary ammonium salt, a phosphonium salt, a diazonium salt, an iodonium salt, or the like. Among these, the sulfonium salt is preferred from the viewpoints of easy availability and easy production of a product with superior adhesion and transparency.

[0052] Examples of the sulfonium salt include triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, and triphenylsulfonium hexafluoroarsinate.

[0053] Examples of the quaternary ammonium salt include tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, and tetrabutylammonium hydrogen sulfate. Examples of the phosphonium salt include ethyltriphenylphosphonium hexafluoroantimonate and tetrabutylphosphonium hexafluoroantimonate.

[0054] Examples of the diazonium salt include benzene diazonium chloride, etc. Examples of the iodonium salt include diphenyl iodonium hexafluoroarsinate, bis(4-chlorophenyl) iodonium hexafluoroarsinate, bis(4-bromophenyl) iodonium hexafluoroarsinate, and phenyl(4-methoxyphenyl) iodonium hexafluoroarsinate, etc.

[0055] 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 30 parts by mass or less, more preferably 0.3 parts by mass or more and 20 parts by mass or less, and particularly preferably 0.5 parts 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.

[0056] When a thermosetting resin is used, a curing catalyst such as an imidazole-based curing catalyst may be used.

[0057] In this embodiment, the curable adhesive may contain a flexibility adjusting component together with the energy ray curable resin or the thermosetting resin in order to easily maintain the sheet shape before curing. Examples of polymers used as the flexibility adjusting component include phenoxy resin, polyolefin resin or modified product thereof, polyamideimide resin, polyimide resin, rubber resin, and acrylic resin.

[0058] These flexibility adjusting components may be used alone or in combination of two or more.

[0059] When the curable adhesive used in this embodiment contains a flexibility adjusting component, the total amount of the energy ray curable resin and the thermosetting resin contained in the adhesive is preferably 15 parts by mass or more and 300 parts by mass or less, more preferably 30 parts by mass or more and 250 parts by mass or less, and even more preferably 60 parts by mass or more and 200 parts by mass or less, relative to 100 parts by mass of the flexibility adjusting component, from the viewpoint of adjusting the storage modulus of the resin layer 3 to the above-mentioned range. In addition, when the adhesive contains an energy ray curable resin or a thermosetting resin but does not contain a flexibility adjusting component, the storage modulus of the resin layer 3 tends to be too high.

[0060] In this embodiment, it is preferable that the curable adhesive does not contain a filler. When the adhesive does not contain a filler, it is possible to prevent the storage modulus of the resin layer 3 at 23° C. from becoming too high. However, the curable adhesive may contain a filler as long as the storage modulus of the resin layer 3 at 23° C. can be adjusted to fall within the above range.

[0061] Examples of the filler include inorganic powders such as silica, alumina, talc, calcium carbonate, titanium white, red iron oxide, silicon carbide, and boron nitride; beads obtained by sphering inorganic powders, single crystal fibers, and glass fibers. Among these, silica filler and alumina filler are preferred. The filler may be used alone or in combination of two or more.

[0062] The curable adhesive may contain other components, such as well-known additives, such as organic solvents, coupling agents, flame retardants, tackifiers, UV absorbers, antioxidants, preservatives, fungicides, plasticizers, defoamers, and wettability adjusters.

[0063] (electrode) The electrodes 4 are used to supply a current to the conductive linear body 21. The electrodes 4 are in a pair. 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.

[0064] 3, electrode 4 is required to have, in cross-sectional view, pedestal portion 41 and step portion 42 provided on pedestal portion 41 and narrower than pedestal portion 41. Without step portion 42, changes in the resistance value of wiring sheet 100 cannot be sufficiently suppressed. Moreover, the electrode 4 has a three-stage configuration in total, with the base portion 41 being the first stage portion and the step portion 42 being the second stage portion 421 and the third stage portion 422. In this case, the electrode 4 has a total of six edges, four edges for the step portion 42 and two edges for the base portion 41. The electrode 4 preferably has three or more edges, and more preferably has four or more edges. The electrode 4 preferably has ten or less edges, and more preferably has eight or less edges. The third step 422 of the step portion 42 is the portion where the thickness of the electrode 4 is maximum, and this height is the maximum thickness H of the electrode. The height of pedestal portion 41 is 1 / 3 of the maximum thickness H of electrode 4. Here, the height of pedestal portion 41 is preferably 1 / 5 or more and 4 / 5 or less of H, and more preferably 1 / 4 or more and 3 / 4 or less of H. Of the width W2 of the second stage portion 421 and the width W3 of the third stage portion 422, the width W2 of the second stage portion 421 is the width of the step portion 42. The width W2 of the second stage portion 421 is 2 / 3 of the width W1 of the base portion 41. In addition, the width W3 of the third stage portion 422 is 1 / 3 of the width W1 of the base portion 41. Here, the width W2 of the step portion 42 is preferably 1 / 5 or more and 4 / 5 or less of W1, and more preferably 1 / 4 or more and 3 / 4 or less of W1.

[0065] The maximum thickness H of the electrode 4 is preferably 40 μm or less. If the maximum thickness H is 40 μm or less, it is possible to prevent problems such as the conductive linear body 21 being unable to follow. From the same viewpoint, the maximum thickness H is more preferably 30 μm or less, and even more preferably 20 μm or less. Furthermore, from the viewpoint of providing both the pedestal portion 41 and the step portion 42, the maximum thickness H is preferably 5 μm or more, more preferably 8 μm or more, and even more preferably 10 μm or more.

[0066] It is sufficient that the width W2 of the step portion 42 is narrower than the width W1 of the pedestal portion 41. However, the width W1 of the pedestal portion 41, which is the maximum width of the electrode 4, is preferably 1 mm or more and 10 mm or less. If the width W1 is within the above range, a contact point with the conductive linear object 21 can be secured. From the same viewpoint, the width W1 of the pedestal portion 41 is more preferably 1.5 mm or more, and even more preferably 2 mm or more. The width W1 of the pedestal portion 41 is more preferably 8 mm or less, even more preferably 6 mm or less, and particularly preferably 4 mm or less.

[0067] The electrode 4 is not limited to such a configuration, and may be, for example, in the following form. Another embodiment of the electrode 4 is an electrode 4A shown in Fig. 4(A). In the electrode 4A, in a cross-sectional view, a step portion 42 provided on a pedestal portion 41 extends from one end of the pedestal portion 41, through the center of the pedestal portion 41, to the other end side of the pedestal portion 41, and does not reach the other end of the pedestal portion 41. A width W2 of the step portion 42 is 3 / 4 of a width W1 of the pedestal portion 41. A height of the pedestal portion 41 is 1 / 3 of a maximum thickness H of the electrode 4. In this case, the number of edges of the electrode 4 is three.

[0068] Another embodiment of the electrode 4 is an electrode 4B shown in FIG. 4(B). In the electrode 4B, in a cross-sectional view, a step portion 42 provided on a pedestal portion 41 extends from the inside of one end of the pedestal portion 41, through the center of the pedestal portion 41, to the other end side of the pedestal portion 41, and does not reach the other end of the pedestal portion 41. The step portion 42 is provided approximately in the center of the pedestal portion 41. The width W2 of the step portion 42 is 1 / 3 of the width W1 of the pedestal portion 41. The height of the pedestal portion 41 is 1 / 2 the maximum thickness H of the electrode 4. In this case, the number of edges of the electrode 4 is four.

[0069] Another embodiment of the electrode 4 is an electrode 4C shown in FIG. 4(C). In the electrode 4C, in a cross-sectional view, a step portion 42 provided on a pedestal portion 41 extends from the inside of one end of the pedestal portion 41, through the center of the pedestal portion 41, to the other end side of the pedestal portion 41, and does not reach the other end of the pedestal portion 41. The step portion 42 is provided approximately in the center of the pedestal portion 41. The width W2 of the step portion 42 is 2 / 3 of the width W1 of the pedestal portion 41. The height of the pedestal portion 41 is 2 / 3 of the maximum thickness H of the electrode 4. In this case, the number of edges of the electrode 4 is four.

[0070] Another embodiment of the electrode 4 is an electrode 4D shown in FIG. 4(D). In the electrode 4D, in a cross-sectional view, a step portion 42 provided on a pedestal portion 41 extends from the inside of one end of the pedestal portion 41, through the center of the pedestal portion 41, to the other end side of the pedestal portion 41, and does not reach the other end of the pedestal portion 41. The step portion 42 is provided approximately in the center of the pedestal portion 41. The width W2 of the step portion 42 is 1 / 3 of the width W1 of the pedestal portion 41. The height of the pedestal portion 41 is 1 / 3 of the maximum thickness H of the electrode 4. In this case, the number of edges of the electrode 4 is four.

[0071] The Young's modulus of electrode 4 is 100×10 9 The Young's modulus of the electrode 4 is preferably 100×10 9 If the Young's modulus of the electrode 4 is less than 85×10 Pa, the contact resistance between the conductive linear body 21 and the electrode 4 tends to be smaller. 9 Pa or less, and more preferably 70×10 9 More preferably, the surface tension is 55×10 Pa or less. 9 Pa or less is particularly preferable, and 40×10 9 It is highly preferable that the Young's modulus of the electrode 4 is 1×10 Pa or less. 9 Pa may be more than 5 x 10 9 It may be 1 Pa or more. The Young's modulus of the electrode 4 can be measured by a continuous stiffness measurement method. For example, the Young's modulus of an electrode provided on a glass substrate at 25° C. can be measured using a nanoindenter (manufactured by MTS Systems) under the following conditions. Indenter shape: triangular pyramid Maximum indentation depth: 500 nm Vibration frequency: 75Hz

[0072] The electrodes 4 can be formed using known electrode materials, such as conductive pastes, such as silver paste, and metal foils, such as solder alloy foils. Examples of the conductive paste include silver paste, copper paste, carbon paste, etc. Among these, silver paste is preferred from the viewpoint of low volume resistivity.

[0073] The electrode 4 is preferably gold-plated, which can suppress migration of the electrode 4.

[0074] (Use of wiring sheet, etc.) The wiring sheet 100 according to the present embodiment can be suitably used, for example, as a sheet heater. In this case, examples of uses of the sheet heater include a defogger for window glass and a defroster. In addition to being used as a sheet heater, the sheet heater can also be used as a flat cable for wiring electrical signals.

[0075] The rate of change in resistance value when the wiring sheet 100 is used in a humid and hot environment is preferably 20% or less, more preferably 15% or less, even more preferably 10% or less, and particularly preferably 5% or less. When the rate of change in resistance value is within this range, the wiring sheet can be used in a humid and hot environment. A method for measuring the rate of change in resistance value is shown in the Examples.

[0076] [Method of manufacturing wiring sheet] Next, a method for manufacturing wiring sheet 100 according to this embodiment will be described. The method for manufacturing the wiring sheet 100 according to the present embodiment is a method capable of producing the above-mentioned wiring sheet 100. The method for manufacturing the wiring sheet 100 according to the present embodiment is a method including a step of applying a conductive paste to form pedestal portion 41 (pedestal portion forming step), and a step of applying a conductive paste narrower than pedestal portion 41 onto pedestal portion 41 to form stepped portion 42 (stepped portion forming step). The method for manufacturing the wiring sheet 100 according to the present embodiment may further include a step of bonding a wiring body film including wiring body 2 to the pair of electrodes 4 (wiring body attaching step).

[0077] In the pedestal portion forming step, a conductive paste is applied onto the substrate 1, and then the conductive paste is dried, thereby forming the pedestal portion 41. The substrate 1 and the conductive paste are as described above. The conductive paste is applied in a predetermined arrangement on the substrate 1 so as to form a pair of electrodes 4. Examples of the application device include a printer and a dispenser.

[0078] In the step forming step, a conductive paste is applied onto the base 41 in a width narrower than that of the base 41, and then dried to form the step 42. By this step, a pair of electrodes 4 can be formed on the substrate 1. The conductive paste is applied onto pedestal portion 41 in a width narrower than width W1 of pedestal portion 41 along pedestal portion 41. The application device and the conductive paste are as described above. Furthermore, when the third step portion 422 is formed on the second step portion 421 of the step portion 42, the coating film of the third step portion 422 may be formed on the coating film of the second step portion 421.

[0079] In the wiring body attachment step, a wiring body film including a wiring body 2 is attached to a pair of electrodes 4. Specifically, the wiring body film is attached onto a substrate 1 provided with a pair of electrodes 4 such that the pair of electrodes 4 contact both ends of the conductive linear body 21 in the wiring body 2 of the wiring body film. Then, after peeling off the release film, a predetermined heat treatment is performed on the thermosetting adhesive to form a resin layer 3, and the wiring sheet 100 can be produced. The wiring body film including the wiring body 2 can be produced, for example, by the following process. In this step, a thermosetting adhesive for forming the resin layer 3 is applied onto the release film to form a coating film. Next, the coating film is dried to form an adhesive layer. Next, the conductive linear bodies 21 are arranged on the adhesive layer to form the wiring body 2. For example, in a state where an adhesive layer with a release film is arranged on the outer circumferential surface of a drum member, the conductive linear bodies 21 are spirally wound onto the adhesive layer while rotating the drum member. Then, the bundle of conductive linear bodies 21 wound in a spiral shape is cut along the axial direction of the drum member. This forms the wiring body 2 and places it on the adhesive layer. In this way, a wiring body film in which the wiring body 2 is formed on the adhesive layer with a release film is obtained. According to this method, for example, by moving the unwinding portion of the conductive linear bodies 21 along a direction parallel to the axis of the drum member while rotating the drum member, it is easy to adjust the interval L between adjacent conductive linear bodies 21 in the wiring body 2.

[0080] [Effects of the embodiment] According to this embodiment, the following advantageous effects can be obtained. (1) According to the present embodiment, even when left in a hot and humid environment, changes in the resistance value of wiring sheet 100 can be suppressed. (2) According to this embodiment, the resin layer 3 can fix the conductive linear body 21, suppress deformation in the thickness direction inside the wiring sheet 100, stabilize the contact between the conductive linear body 21 and the electrode 4, and stabilize the resistance value of the wiring body 2. (3) According to the present embodiment, the electrode 4 having the base portion 41 and the step portion 42 in a cross-sectional view can be easily formed by, for example, printing the conductive paste multiple times.

[0081] [Modifications of the embodiment] The present invention is not limited to the above-described embodiment, and any modifications or improvements that can achieve the object of the present invention are included in 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 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 addition, in the above-described embodiment, the resin layer 3 is disposed on the surface of the wiring sheet 100, but this is not limited thereto. For example, a protective sheet (not shown) may be provided on the resin layer 3 of the wiring sheet 100 to protect the wiring body 2. EXAMPLES

[0082] 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. Moreover, the wiring sheets obtained in the examples were evaluated as follows.

[0083] [Resistance value evaluation] A resistance meter (manufactured by Hioki E.E. Corporation, product name "RM3545") was connected to the electrodes, and the resistance value (R 1 After leaving the wiring sheet for 100 hours in a humid and hot environment at a temperature of 85°C and a humidity of 85% RH, a resistance meter was connected to the electrodes and the resistance value (R 2 ) was measured. Then, from the following formula (F1), R 1 and R 2 The rate of change in resistance (unit: %) was calculated. The smaller this rate of change in resistance, the more the change in resistance of the wiring sheet is suppressed. Resistance change rate = [(R 2 -R 1 ) / R 1 ]×100(%) ···(F1)

[0084] [Preparation Example 1] A curable adhesive was obtained by blending 100 parts by mass of a phenoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "YX7200B35") with 170 parts by mass of a polyfunctional hydrogenated bisphenol A diglycidyl ether epoxy compound (manufactured by Mitsubishi Chemical Corporation, product name "YX8000"), 0.2 parts by mass of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KBM-4803"), 2 parts by mass of a thermal cationic polymerization initiator (manufactured by Sanshin Chemical Industry Co., Ltd., product name "San-Aid SI-B3"), and 2 parts by mass of a thermal cationic polymerization initiator (manufactured by Sanshin Chemical Industry Co., Ltd., product name "San-Aid SI-B7").

[0085] [Preparation Example 2] (Preparation of (meth)acrylic acid ester polymer (A)) 55 parts by mass of 2-ethylhexyl acrylate, 5 parts by mass of 4-acryloylmorpholine, 15 parts by mass of isobornyl acrylate, and 25 parts by mass of 2-hydroxyethyl acrylate were copolymerized by solution polymerization to prepare a (meth)acrylic acid ester polymer (A). The molecular weight of this (meth)acrylic acid ester polymer (A) was measured by the method described below, and the weight average molecular weight (Mw) was 600,000. (Preparation of adhesive composition) 100 parts by mass (solid content equivalent; the same applies below) of the (meth)acrylic acid ester polymer (A) obtained in the above process, 0.18 parts by mass of trimethylolpropane-modified tolylene diisocyanate as a crosslinking agent (B), 7 parts by mass of ε-caprolactone-modified tris-(2-acryloxyethyl)isocyanurate as an active energy ray-curable component (C), 0.7 parts by mass of a mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone in a 1:1 mass ratio as a photopolymerization initiator (D), and 0.28 parts by mass of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent were mixed, thoroughly stirred, and diluted with methyl ethyl ketone to obtain a coating solution of an adhesive composition.

[0086] [Example 1] (Wire wiring film) The adhesive obtained in Preparation Example 1 was applied to a thickness of 10 μm on a release film having a thickness of 38 μm (manufactured by Lintec Corporation, product name "SP-PET382150") and cut into a rectangle of 250 mm × 320 mm to prepare an adhesive sheet. A carbon-coated tungsten wire (diameter 12 μm, volume resistivity 1.64 × 10 -5 Ω·m, hereinafter also referred to as wire) was prepared. Next, the obtained adhesive sheet was wrapped around a drum member whose outer periphery is made of rubber, with the surface of the adhesive layer facing outward so as not to wrinkle, and both ends of the adhesive sheet in the circumferential direction were fixed with double-sided tape. The wire wound around the bobbin was attached to the surface of the adhesive layer of the adhesive sheet located near the end of the drum member, and the wire was wound around the drum member while being unwound, and the drum member was moved little by little in a direction parallel to the drum axis so that the wire was wound around the drum member while drawing a spiral at equal intervals of 3 mm. In this way, a wiring body was formed with 96 wires lined up on the surface of the adhesive. After that, the wire was cut and removed from the drum member. The wiring body was cut to a width of 40 x 82 mm so that 12 wires could be taken out, and a wiring body film was produced.

[0087] (Preparation of substrate with electrodes) On a 2 mm thick glass sheet, silver paste (manufactured by Jujo Chemical Co., Ltd., product name "#2 TF silver paste") was screen printed to a width of 3 mm with an interelectrode distance of 7.8 mm, and then dried at 150°C for 30 minutes to form a coating film with a thickness of 6 μm. Next, the same silver paste was screen printed on the printed silver paste with a width of 2 mm, and then dried at 150°C for 30 minutes to form a coating film with a thickness of 6 μm. Furthermore, the same silver paste was screen printed on the second printed silver paste with a width of 1 mm, and then dried at 150°C for 30 minutes to form a coating film with a thickness of 6 μm, to produce a substrate with electrodes. The Young's modulus of the electrodes was 24×10 9 The coating width and coating thickness of the first, second and third stages of the obtained electrode are shown in Table 1.

[0088] (Creating wiring sheets) The wiring film was attached to the electrode-attached substrate so that the electrodes were located at both ends of the wires, and then heated at 120° C., 0.5 MPa, and for 30 minutes to obtain a wiring sheet. (Preparation of protective sheet) The adhesive composition obtained in Preparation Example 2 was applied to a thickness of 100 μm on a cycloolefin polymer film (manufactured by Zeon Corporation, product name "ZF16") having a thickness of 100 μm, and cut into a rectangle of 50 mm × 120 mm. Then, a circle having a diameter of 5 mm was cut out so that the center-to-center distance between the two circles was 7.8 mm, to prepare a protective sheet. (Preparation of wiring sheet with protective sheet) The protective sheet was attached to the wiring sheet so that the electrodes of the wiring sheet and the circles of the protective sheet were aligned. Then, ultraviolet light with a wavelength of 365 nm and an illuminance of 200 mW / cm was applied. 2 , light intensity 1000mJ / cm 2 A wiring sheet with a protective sheet was obtained.

[0089] [Examples 2 to 5 and Comparative Example 1] A wiring sheet with a protective sheet was produced in the same manner as in Example 1, except that the coating width and coating thickness of the first and second stages of the electrode were changed as shown in Table 1.

[0090] [Table 1]

[0091] The wiring sheets obtained in Examples 1 to 5 had good results in the resistance evaluation, which confirmed that the present invention can suppress changes in the resistance of the wiring sheet. [Explanation of symbols]

[0092] 1... Base material, 2... Wiring body, 21... Conductive linear body, 3... Resin layer, 4,4A,4B,4C,4D... Electrode, 41... Pedestal part, 42... Step part, 421... Second step part, 422... Third step part, 100... Wiring sheet.

Claims

1. A wiring body including a conductive linear body; A pair of electrodes in direct contact with the conductive linear body; Equipped with The electrode has, in a cross-sectional view, a base portion and a step portion provided on the base portion and having a narrower width than the base portion. Wiring sheet.

2. The wiring sheet according to claim 1 , The Young's modulus of the electrode is 100×10 ９ Pa or less, Wiring sheet.

3. The wiring sheet according to claim 1 or 2, The maximum thickness of the electrode is 40 μm or less. Wiring sheet.

4. The wiring sheet according to claim 1 or 2, The maximum width of the electrode is 1 mm or more and 10 mm or less. Wiring sheet.

5. The wiring sheet according to claim 1 or 2, Further, a resin layer is provided to directly or indirectly support the wiring body. Wiring sheet.

6. The wiring sheet according to claim 1 or 2, The wiring body is a plurality of the conductive linear bodies arranged at intervals. Wiring sheet.

7. A method for manufacturing a wiring sheet including a wiring body having a conductive linear body and a pair of electrodes in direct contact with the conductive linear body, comprising: applying a conductive paste to form a base portion; a step of applying a conductive paste onto the base portion so as to have a width narrower than that of the base portion to form a step portion; Equipped with A method for manufacturing a wiring sheet.

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