Wiring sheet and method for manufacturing the same

Abstract

To provide a wiring sheet that can suppress the generation of air bubbles around conductive wires and has excellent resistance to humid heat. [Solution] A wiring sheet 100 comprising a wiring body 2 having a conductive linear body 21, a pair of electrodes 4 in direct contact with the conductive linear body 21, a first resin layer 3 that directly or indirectly supports the wiring body 2, a first base material 1 that directly or indirectly supports the first resin layer 3, a second resin layer 5 that directly or indirectly supports the wiring body 2, and a second base material 6 that directly or indirectly supports the second resin layer 5, wherein the first base material 1, the first resin layer 3, the wiring body 2, the electrodes 4, the second resin layer 5, and the second base material 6 are arranged in this order in the thickness direction, and the sum of the thickness of the first resin layer 3 and the thickness of the second resin layer 5 is equal to or greater than the diameter of the conductive linear body 21.

Description

[Technical Field]

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

[0002] As a wiring sheet that can be used for planar heater applications, for example, Patent Document 1 describes a conductive sheet having a pseudo-sheet structure in which a plurality of linear bodies extending in one direction are arranged at intervals. A wiring sheet that can be used as a heating element is obtained by providing a pair of electrodes at both ends of the plurality of linear bodies. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2017 / 086395 [Overview of the project] [Problems that the invention aims to solve]

[0004] The wiring sheet described in Patent Document 1 may have a protective layer provided on top of the linear body and electrodes to protect the linear body or electrodes. In such cases, the protective layer is also attached by the adhesive layer to which the linear body and electrodes are attached. However, it has been found that air bubbles are generated around the conductive linear body in this adhesive layer. On the other hand, it has been found that the generation of air bubbles can be suppressed by increasing the thickness of this adhesive layer, but in this case, the moisture heat durability of the wiring sheet decreases. Therefore, while it is not a problem if only one of the required performances is needed, it has been difficult to achieve both performances simultaneously.

[0005] The object of the present invention is to provide a wiring sheet and a method for manufacturing the same that can suppress the generation of air bubbles around conductive wires and have excellent resistance to moist heat. [Means for solving the problem]

[0006] [1] A wiring body comprising a conductive linear body, A pair of electrodes in direct contact with the conductive linear body, A first resin layer that directly or indirectly supports the wiring assembly, A first substrate that directly or indirectly supports the first resin layer, A second resin layer that directly or indirectly supports the wiring assembly, The invention comprises a second substrate that directly or indirectly supports the second resin layer, The first substrate, the first resin layer, the wiring body, the electrode, the second resin layer, and the second substrate are arranged in this order in the thickness direction. The sum of the thickness of the first resin layer and the thickness of the second resin layer is equal to or greater than the diameter of the conductive linear body. Wiring sheet.

[0007] [2] In the wiring sheet described in [1], The storage moduli of the first resin layer and the second resin layer at 23°C are, respectively, 1.0 × 10⁻⁶. 4 Pa or higher, 5.0×10 6 It is less than or equal to Pa. Wiring sheet.

[0008] [3] In the wiring sheet described in [1] or [2], The thicknesses of the first resin layer and the second resin layer are 5 μm or more and 100 μm or less, respectively. Wiring sheet.

[0009] [4] In the wiring sheet described in any of [1] to [3], The wiring body has a structure in which a plurality of the conductive linear bodies are arranged at intervals. Wiring sheet.

[0010] [5] In the wiring sheet described in any of [1] to [3], The conductive linear body has a pattern formed in plan view that has at least one bent portion. Wiring sheet.

[0011] [6] In the wiring sheet according to [5], the wiring body consists of only one of the conductive linear bodies, Wiring sheet.

[0012] [7] In the wiring sheet according to [5], the wiring body includes two or more of the conductive linear bodies, Wiring sheet.

[0013] [8] A method for manufacturing the wiring sheet according to any one of [1] to [7], a step of forming the first resin layer on the first base material to produce a first resin sheet; a step of forming the second resin layer on the second base material to produce a second resin sheet; a step of attaching the conductive linear body on the first resin layer of the first resin sheet to form the wiring body; a step of forming the pair of electrodes on the conductive linear body; a step of laminating the second resin sheet such that the first resin layer of the first resin sheet and the second resin layer of the second resin sheet face each other on the pair of electrodes, Method for manufacturing a wiring sheet. [Advantages of the Invention]

[0014] According to one aspect of the present invention, it is possible to provide a wiring sheet that can suppress the generation of bubbles around the conductive linear body and has excellent damp heat durability, and a method for manufacturing the same. [Brief Description of the Drawings]

[0015] [Figure 1] It is a schematic diagram showing a wiring sheet according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view showing the cross-section II-II of FIG. 1. [Figure 3] It is a schematic diagram showing a modified form of the wiring body in an embodiment of the present invention. [Figure 4]This is a schematic diagram illustrating a method for manufacturing a wiring sheet according to an embodiment of the present invention. [Modes for carrying out the invention]

[0016] [Embodiment] The present invention will be described below with reference to embodiments, based on the drawings. The present invention is not limited to the embodiments. Note that some parts of the drawings have been enlarged or reduced in size for the purpose of facilitating explanation.

[0017] [Wiring sheet] As shown in Figures 1 and 2, the wiring sheet 100 according to this embodiment comprises a first base material 1, a wiring body 2, a first resin layer 3, a pair of electrodes 4, a second resin layer 5, and a second base material 6. The wiring body 2 consists of multiple conductive linear bodies 21 arranged at intervals. The first resin layer 3 directly or indirectly supports the wiring body 2. As shown in Figure 2, the electrodes 4 are provided between the first resin layer 3 and the second resin layer 5 and are in direct contact with the conductive linear bodies 21. A pair of electrodes 4 and a power supply (not shown) can be electrically connected. The first base material 1 and the second base material 6 are provided so as to cover the first resin layer 3 and the second resin layer 5, respectively. Furthermore, as shown in Figure 2, the wiring sheet 100 must be provided in the following order: first base material 1, first resin layer 3, wiring body 2 (conductive wire 21), electrode 4, second resin layer 5, and second base material 6. Additionally, the sum of the thicknesses of the first resin layer 3 and the second resin layer 5 must be equal to or greater than the diameter of the conductive wire 21.

[0018] The inventors surmise that the reason why the wiring sheet 100 according to this embodiment can suppress the generation of air bubbles around conductive wires and has excellent resistance to humid heat is as follows. In other words, the wiring sheet 100 is provided in the following order: first base material 1, first resin layer 3, wiring body 2 (conductive wire 21), electrode 4, second resin layer 5, and second base material 6. The sum of the thicknesses of the first resin layer 3 and the second resin layer 5 is equal to or greater than the diameter of the conductive wire 21. As a result, the first resin layer 3 ensures contact between the wiring body 2 (conductive wire 21) and the electrode 4, and the second resin layer 5 can embed the conductive wire 21 and the electrode 4. The inventors surmise that this suppresses the generation of air bubbles around the conductive wire while ensuring durability against humid heat.

[0019] (base material) The first substrate 1 directly or indirectly supports the first resin layer 3. Furthermore, the first substrate 1 and the second substrate 6 directly or indirectly support the second resin layer 5. Examples of materials for the first base material 1 and the second base material 6 include resin, paper, metal, nonwoven fabric, cloth, and glass. Among these, resin or glass is preferred from the viewpoint of strength or handling properties. Examples of resins used for the first base material 1 and the second base material 6 include polyurethane, polyethylene, polypropylene, polystyrene, polycarbonate, and polyacetal.

[0020] The thickness of the first substrate 1 and the second substrate 6 is preferably 10 μm or more, more preferably 18 μm or more, and even more preferably 26 μm or more. The thickness of the first substrate 1 and the second substrate 6 is preferably 10 mm or less, more preferably 1 mm or less, and even more preferably 300 μm or less. Excellent strength and other properties can be obtained when the thickness of the first substrate 1 and the second substrate 6 are within the above range.

[0021] (Wiring) The wiring body 2 preferably has a structure in which a plurality of conductive linear bodies 21 are arranged at intervals, as shown in Figures 1 and 2. Furthermore, as shown in Figures 1 and 2, it is preferable that the conductive linear bodies 21 are arranged in parallel. The electrodes 4 are electrically connected to both ends of the conductive linear bodies 21. In this case, the spacing L of the conductive wires 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. Furthermore, the spacing L of the conductive wires 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 the conductive wires 21 is within the above range, the conductive wires are densely packed to a certain extent, which improves the function of the wiring sheet 100, such as maintaining a low resistance of the wiring body 2.

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

[0023] Note that the wiring assembly 2 is not limited to this configuration, and may also be in the following form, for example. Another embodiment of the wiring body 2 is the wiring body 2A shown in Figure 3(A). The wiring body 2A comprises conductive linear bodies 21 having a pattern in which at least one bent portion 211 is formed in a plan view. Preferably, the wiring body 2A comprises two conductive linear bodies 21, as shown in Figure 3(A). However, the wiring body 2A may consist of only one conductive linear body 21. Also, the number of conductive linear bodies 21 may be two or more. In such a case, the contact portion between the wiring body 2A and the electrode 4 is only the portion at both ends of the two conductive linear bodies 21, so the area of ​​the electrode 4 can be reduced. This improves the curved surface conformability of the wiring sheet 100.

[0024] Preferably, the wiring body 2A comprises a conductive wire 21 formed in a fork-shaped pattern, as shown in Figure 3(A). Furthermore, if the side with the pair of electrodes 4 is considered the lower side, the conductive wire 21 extends upward from the electrode 4 located in the lower center left, bends at a right angle at the bend portion 211 and extends to the left, then bends at a right angle at the bend portion 211 and extends upward. Then, bends at a right angle at the bend portion 211 and extends to the right, and immediately after, bends at a right angle at the next bend portion 211 and extends downward. In this way, one tip of the fork is formed. Subsequently, while forming a fork-shaped pattern, the conductive wire 21 reaches the electrode 4 located in the lower center right. When the wire bends at a right angle at the bend portion 211 in this way, there is an advantage in that the pattern is easy to form. In this case, the number of fork tips is three. The number of fork tips is not limited, but the more fork tips there are, the denser the pattern that can be formed. Preferably, the number of fork tips is two or more, more preferably four or more, and even more preferably six or more. Furthermore, it is preferable that the wiring body 2A comprises a conductive linear body 21 formed in a fork-shaped pattern, as shown in Figure 3(A), and another conductive linear body 21 formed in a fork-shaped pattern located inside it. Thus, the patterns of the two conductive linear bodies 21 may be the same.

[0025] Another embodiment of the wiring body 2 is the wiring body 2B shown in Figure 3(B). The wiring body 2B comprises a conductive linear body 21 having a pattern in which at least one bent portion 211 is formed in a plan view. In this case, the contact portion between the wiring body 2B and the electrode 4 is only the portion at both ends of a single conductive linear body 21, so the area of ​​the electrode 4 can be reduced. This improves the curve-following ability of the wiring sheet 100.

[0026] Preferably, the wiring body 2B comprises a conductive linear body 21 formed in a rectangular tunnel shape, as shown in Figure 3(B). Furthermore, when the side with the pair of electrodes 4 is considered the bottom, the conductive linear body 21 extends upward from the electrode 4 located in the lower center left, bends at a right angle at a bend 211 near the center and extends to the left, then bends at a right angle at a bend 211 near the left end and extends downward. Then, it bends at a right angle at a bend 211 at the lower end and extends to the left, bends at a right angle at a bend 211 at the lower left end and extends upward, and bends at a right angle at a bend 211 at the upper left end and extends to the right. Furthermore, at the bend 211 on the upper right end, it bends at a right angle and extends downwards, and at the bend 211 on the lower right end, it bends at a right angle and extends to the left. Then, at the next bend 211, it bends at a right angle and extends upwards, and at the bend 211 located slightly past the midpoint between the upper and lower ends, it bends at a right angle and extends to the left, and finally, at the bend 211 near the center, it bends at a right angle and extends downwards. In this way, a rectangular tunnel-shaped pattern can be formed. Furthermore, the wiring body 2B may comprise a conductive linear body 21 formed in a rectangular tunnel shape pattern, and another conductive linear body 21 formed in a rectangular tunnel shape pattern located inside it. The patterns of the two conductive linear bodies 21 may be the same or different.

[0027] The volume resistivity of the conductive linear body 21 is 1.0 × 10⁻⁶. -9 Preferably, it is Ω·m or greater, and 3.0 × 10 -9 It is more preferable that it be Ω·m or greater, and 1.0 × 10 -8 It is even more preferable that the resistivity is Ω·m or greater. Furthermore, the volume resistivity of the conductive linear body 21 is 1.0 × 10⁻⁶. -3 It is preferable that it be Ω·m or less, and 1.0 × 10 -4 It is more preferable that it be Ω·m or less, and 5.0 × 10 -5More preferably, it is below Ω·m. When the volume resistivity of the conductive linear body 21 is within the above range, the surface resistance of the wiring body 2 is likely to decrease. The measurement of the volume resistivity of the conductive linear body 21 is as follows. Apply silver paste to the end portion of the conductive linear body 21 and the portion having a length of 40 mm from the end portion, and measure the resistance of the end portion and the portion having a length of 40 mm from the end portion. Then, multiply the cross-sectional area (unit: m 2 ) of the conductive linear body 21 by the above resistance value, and divide the obtained value by the above measured length (0.04 m) to calculate the volume resistivity of the conductive linear body 21.

[0028] The shape of the cross-section of the conductive linear body 21 is not particularly limited, and can be, for example, polygonal, flat, elliptical, or circular. From the viewpoint of compatibility with the first resin layer 3 and the like, the shape of the cross-section of the conductive linear body 21 is preferably elliptical or circular.

[0029] When the cross-section of the conductive linear body 21 is circular, the diameter D (see FIG. 2) of the conductive linear body 21 is preferably 3 μm or more and 200 μm or less. From the viewpoint 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 body 21 is more preferably 5 μm or more, and even more preferably 9 μm or more. The diameter D of the conductive linear body 21 is more preferably 150 μm or less, even more preferably 100 μm or less, particularly preferably 50 μm or less, and very preferably 40 μm or less. When the cross-section of the conductive linear body 21 is elliptical, it is preferable that the major axis is in the same range as the above diameter D.

[0030] The diameter D of the conductive linear body 21 is measured using a digital microscope. Observe the conductive linear body 21, measure the diameter of the conductive linear body 21 at 5 randomly selected locations, and take the average value.

[0031] The form of the conductive linear body 21 is not particularly limited and can be manufactured by etching, screen printing, or inkjet printing, but it is preferable that it be a linear body containing a metal wire (hereinafter also referred to as "metal wire linear body"). Metal wires have high thermal conductivity, high electrical conductivity, and high handling properties. Metal wire linear bodies can significantly reduce resistance, and even if the diameter of the metal wire linear body is made extremely small, it can conduct electricity with the current necessary for heating the wiring sheet 100. This makes the conductive linear body 21 difficult to see. In other words, by using a metal wire linear body as the conductive linear body 21, the resistance value of the wiring body 2 is reduced while light transmittance is easily improved. In addition, the wiring sheet 100 is more likely to heat up quickly. Furthermore, as mentioned above, it is easier to obtain a linear body with a small diameter. In addition to metal wires, conductive linear bodies 21 can also include linear bodies containing carbon nanotubes and linear bodies in which a conductive coating is applied to a thread.

[0032] The metal wire may be a wire made of a single metal wire, or it may be a wire made by twisting together multiple metal wires. Examples of metal wires include those 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 rhenium tungsten. Furthermore, the metal wire may be plated with gold, tin, zinc, silver, nickel, chromium, nickel-chromium alloy, or solder, or its surface may be coated with carbon materials or polymers, as described later. In particular, wires containing one or more metals selected from tungsten, molybdenum, and alloys containing these are preferred from the viewpoint of low volume resistivity. Metal wires can also be those coated with carbon material. When metal wires are coated with carbon material, their metallic luster is reduced, making it easier to make the metal wires less noticeable. In addition, metal corrosion is suppressed when metal wires are coated with carbon material. Examples of carbon materials used to coat metal wires include carbon black, activated carbon, hard carbon, soft carbon, mesoporous carbon, and amorphous carbon such as carbon fiber; graphite, fullerene, graphene, and carbon nanotubes.

[0033] The conductive linear body 21 may be a linear body in which a conductive coating is applied to a thread. Examples of threads include threads spun from resins such as nylon or polyester. Other examples of threads include metal fibers, carbon fibers, or ionic conductive polymer fibers. Examples of conductive coatings include coatings of metal, conductive polymer, or carbon material. The conductive coating can be formed by plating, vapor deposition, or the like. 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 wiring body 2.

[0034] (Resin layer) The first resin layer 3 directly or indirectly supports the wiring body 2. The second resin layer 5 also directly or indirectly supports the wiring body 2 and is provided, for example, to cover the wiring body 2. Preferably, the first resin layer 3 and the second resin layer 5 are layers containing adhesive. For example, when forming the wiring body 2 on the first resin layer 3, the adhesive facilitates the attachment of the conductive wire 21 to the first resin layer 3. The first resin layer 3 and the second resin layer 5 may be the same as or different from each other.

[0035] The storage modulus of the first resin layer 3 and the second tree species layer 5 at 23°C is 1.0 × 10⁻⁶ 4 Pa or more, 5.0×10 6 It is preferable that it is less than or equal to Pa, 2.0 × 10 4 Pa or more, 1.0×10 6It is more preferable that it be less than or equal to Pa, 3.0 × 10 4 Pa or more, 5.0×10 5 It is even more preferable that the storage modulus is Pa or less. If the storage modulus is within the above range, the conductive linear body 21 and the electrode 4 can be embedded in the first resin layer 3 and the second resin layer 5 while ensuring their contact points.

[0036] The thicknesses of the first resin layer 3 and the second resin layer 5 are preferably 5 μm or more and 100 μm or less, respectively. If the thickness is within the above range, the conductive linear body 21 and the electrode 4 can be embedded in the first resin layer 3 and the second resin layer 5 while ensuring their contact points. Also, from a similar viewpoint, the thickness of the first resin layer 3 is preferably thinner than the thickness of the second resin layer 5. Furthermore, the thickness of the first resin layer 3 is more preferably 10 μm or more, and even more preferably 20 μm or more. The thickness of the first resin layer 3 is more preferably 80 μm or less, and even more preferably 60 μm or less. Also, from the viewpoint of achieving both bubble suppression and humid heat durability, the thickness of the first resin layer 3 is preferably smaller than the diameter of the conductive linear body 21. Furthermore, the thickness of the second resin layer 5 is more preferably 7 μm or more, and even more preferably 10 μm or more. The thickness of the second resin layer 5 is more preferably 50 μm or less, and even more preferably 30 μm or less.

[0037] The sum of the thicknesses of the first resin layer 3 and the second resin layer 5 must be greater than or equal to the diameter D of the conductive wire 21. If the sum of the thicknesses of the first resin layer 3 and the second resin layer 5 is greater than or equal to the diameter D of the conductive wire 21, the wiring 2 and the electrodes 4 can be embedded in the first resin layer 3 and the second resin layer 5. From a similar viewpoint, it is more preferable that the sum of the thicknesses of the first resin layer 3 and the second resin layer 5 is 1 μm or more greater than the diameter D, and even more preferable that it is 3 μm or more greater.

[0038] The first resin layer 3 and the second resin layer 5 may be layers formed from an adhesive containing a pressure-sensitive adhesive. The pressure-sensitive adhesive is not particularly limited. For example, examples of pressure-sensitive adhesives include acrylic adhesives, urethane adhesives, rubber adhesives, polyester adhesives, silicone adhesives, and polyvinyl ether adhesives. Among these, the pressure-sensitive adhesive is preferably at least one selected from the group consisting of acrylic adhesives, urethane adhesives, and rubber adhesives, and more preferably an acrylic adhesive.

[0039] Examples of acrylic adhesives include polymers containing structural units derived from alkyl (meth)acrylates having linear or branched alkyl groups, and acrylic polymers containing structural units derived from (meth)acrylates having a cyclic structure. Here, "(meth)acrylate" is used to refer to both "acrylate" and "methacrylate," and the same applies to other similar terms.

[0040] When the acrylic polymer is a copolymer, the form of copolymerization is not particularly limited. The acrylic copolymer may be a block copolymer, a random copolymer, or a graft copolymer.

[0041] From the viewpoint of achieving a higher storage modulus, the first resin layer 3 and the second resin layer 5 are preferably layers made of cured products of a curable adhesive. Such first resin layer 3 and second resin layer 5 can stabilize the resistance value of the wiring body 2. In other words, these first resin layer 3 and second resin layer 5 can fix the conductive wire 21, stabilize the contact between the conductive wire 21 and the electrode 4, and make it less likely for the resistance value to increase. Examples of curable adhesives include thermosetting adhesives that harden with heat, and energy ray curing adhesives. Examples of energy rays include ultraviolet rays, visible energy rays, infrared rays, and electron beams. Note that "energy ray curing" also includes thermal curing by heating with energy rays.

[0042] Curable adhesives preferably contain a thermosetting resin. The thermosetting resin is not particularly limited, and 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 individually 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 imidazole-based curing catalysts. 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, and epoxy resins are preferred.

[0043] As for the epoxy resin, cyclic epoxy resins, such as aromatic epoxy resins or alicyclic epoxy resins, are preferred from the viewpoint of increasing the storage modulus of the first resin layer 3 and the second resin layer 5. Epoxy resins having flexible segments such as oxyalkylene chains tend to decrease the storage modulus of the first resin layer 3 and the second resin layer 5.

[0044] Energy-ray curable adhesives preferably contain an energy-ray curable resin. 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.

[0045] Examples of 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. Examples include (meth)acrylates containing a chain-like aliphatic skeleton such as acrylate; (meth)acrylates containing a cyclic aliphatic skeleton such as dicyclopentanyl di(meth)acrylate; polyalkylene glycol (meth)acrylates such as polyethylene glycol di(meth)acrylate; oligoester (meth)acrylates, urethane (meth)acrylate oligomers, epoxy-modified (meth)acrylates, polyether (meth)acrylates other than polyalkylene glycol (meth)acrylates, and itaconic acid oligomers.

[0046] The weight-average molecular weight (Mw) of the energy-ray curable resin is preferably 100 or more, and more preferably 300 or more. Furthermore, 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 the value on a standard polystyrene basis measured by gel permeation chromatography (GPC).

[0047] The adhesive may contain only one type of energy-ray curable resin, or two or more types. If there are two or more types of energy-ray curable resins, their combination and ratio can be arbitrarily selected.

[0048] When using energy-ray curable resins or thermosetting resins, it is preferable to use photopolymerization initiators and thermal polymerization initiators. By using photopolymerization initiators and thermal polymerization initiators, the polymerization reaction of the curable resin can be easily initiated, and the curing reaction can be easily controlled.

[0049] Examples of photopolymerization initiators include photoradical polymerization initiators such as benzophenone, acetophenone, benzoin, benzoin methyl ether, 2,4-diethylthioxanthone, 1-hydroxycyclohexylphenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, 2-chloranthraquinone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenyl-phosphine oxide.

[0050] In addition to photoradical polymerization initiators, photocationic polymerization initiators can also be used as photopolymerization initiators. Photocationic polymerization initiators are compounds that generate cation species when irradiated with energy rays, thereby initiating the curing reaction of cationic curable compounds. They consist of a cation part that absorbs energy rays and an anion part that is a source of acid.

[0051] Examples of photocationic polymerization initiators include sulfonium salt compounds, iodonium salt compounds, phosphonium salt compounds, ammonium salt compounds, antimonate salt compounds, diazonium salt compounds, selenium salt compounds, oxonium salt compounds, and bromine salt compounds. Among these, sulfonium salt compounds are preferred from the viewpoint of excellent compatibility and excellent storage stability of the resulting adhesive, and aromatic sulfonium salt compounds having aromatic groups are more preferred.

[0052] Examples of sulfonium salt compounds include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, and triphenylsulfonium tetrakis(pentafluorophenyl)borate.

[0053] Examples of iodonium salt compounds include diphenyliodonium tetrakis(pentafluorophenyl)borate, diphenyliodonium hexafluorophosphate, and (tricumyl)iodonium tetrakis(pentafluorophenyl)borate.

[0054] Examples of phosphonium salt compounds include tri-n-butyl(2,5-dihydroxyphenyl)phosphonium bromide and hexadecyltributylphosphonium chloride.

[0055] Examples of ammonium salt compounds include benzyltrimethylammonium chloride, phenyltributylammonium chloride, and benzyltrimethylammonium bromide.

[0056] Examples of antimonate compounds include triphenylsulfonium hexafluoroantimonate, p-(phenylthio)phenyldiphenylsulfonium hexafluoroantimonate, and diallylodonium hexafluoroantimonate.

[0057] Examples of thermal polymerization initiators 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 organic peroxides such as benzoyl peroxide, lauroyl peroxide, peracetic acid, persuccinic acid, di-t-butyl peroxide, t-butyl hydroperoxide, and cumene hydroperoxide, which are thermal radical polymerization initiators.

[0058] In addition to the thermal radical polymerization initiators mentioned above, thermal cationic polymerization initiators can also be used as thermal polymerization initiators. Thermal cationic polymerization initiators are compounds that can generate cation species that initiate polymerization upon heating. Examples of thermal cationic polymerization initiators include sulfonium salts, quaternary ammonium salts, phosphonium salts, diazonium salts, and iodonium salts. Among these, sulfonium salts are preferred from the viewpoint of being readily available and easily yielding superior adhesion and transparency.

[0059] Examples of sulfonium salts include triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, and triphenylsulfonium hexafluoroalcinate.

[0060] Examples of quaternary ammonium salts include tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, and tetrabutylammonium hydrogen sulfate. Examples of phosphonium salts include ethyltriphenylphosphonium hexafluoroantimonate and tetrabutylphosphonium hexafluoroantimonate.

[0061] Examples of diazonium salts include benzenediazonium chloride. Examples of iodonium salts include diphenyliodonium hexafluoroalcinate, bis(4-chlorophenyl)iodonium hexafluoroalcinate, and phenyl(4-methoxyphenyl)iodonium hexafluoroalcinate.

[0062] These polymerization initiators can be used individually or in combination of two or more. When forming a crosslinked structure using these polymerization initiators, 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, per 100 parts by mass of the energy-curable resin or thermosetting resin.

[0063] Furthermore, when using thermosetting resins, curing catalysts such as imidazole-based curing catalysts may be used.

[0064] In this embodiment, the curable adhesive may contain a flexibility-modifying component along with the energy-ray-curable resin or thermosetting resin to facilitate the maintenance of the sheet shape before curing. Examples of polymers used as flexibility-modifying components include phenoxy resins, polyolefin resins or modified thereof, polyamide-imide resins, polyimide resins, rubber resins, and acrylic resins.

[0065] These flexibility-modifying components can be used individually or in combination of two or more.

[0066] When the curable adhesive used in this embodiment contains a flexibility-adjusting component, the total amount of energy-curable resin and thermosetting resin contained in the adhesive is preferably 15 to 300 parts by mass, more preferably 30 to 250 parts by mass, and even more preferably 60 to 200 parts by mass, per 100 parts by mass of the flexibility-adjusting component, from the viewpoint of adjusting the storage modulus of the first resin layer 3 and the second resin layer 5 to the range described above. Furthermore, when the adhesive contains an energy-curable resin or a thermosetting resin but does not contain a flexibility-adjusting component, the storage modulus of the first resin layer 3 and the second resin layer 5 tends to become too high.

[0067] In this embodiment, it is preferable that the curable adhesive does not contain a filler. If the adhesive does not contain a filler, it is possible to prevent the storage modulus of the first resin layer 3 and the second resin layer 5 from becoming too high at 23°C. However, the curable adhesive may contain a filler to the extent that it can adjust the storage modulus of the first resin layer 3 and the second resin layer 5 at 23°C to within the aforementioned range.

[0068] Examples of fillers include inorganic powders such as silica, alumina, talc, calcium carbonate, titanium white, red iron oxide, silicon carbide, and boron nitride; beads formed from spherical inorganic powders, single crystal fibers, and glass fibers. Among these, silica fillers and alumina fillers are preferred. The fillers may be used individually or in combination of two or more types.

[0069] Curable adhesives may contain other components. Examples of other components include well-known additives such as organic solvents, coupling agents, flame retardants, tackifiers, UV absorbers, antioxidants, preservatives, fungicides, plasticizers, defoamers, and wettability modifiers.

[0070] (electrode) Electrodes 4 are used to supply current to the conductive wire 21. Electrodes 4 come in a pair. Electrodes 4 are in direct contact with the conductive wire 21. Electrodes 4 are electrically connected to both ends of the conductive wire 21. Electrode 4 can be formed using known electrode materials. Examples of electrode materials include conductive pastes such as silver paste; metal foils such as copper foil; and metal wires. When the electrode material is a metal wire, there may be one metal wire, but it is preferable to have two or more.

[0071] When the electrode material is a metal foil or metal wire, the metal of the metal foil or metal wire may be 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 rhenium tungsten. Furthermore, the metal foil or metal wire may be plated with gold, tin, zinc, silver, nickel, chromium, nickel-chromium alloy, or solder.

[0072] The width of at least one of the electrodes 4 is preferably 10 mm or less, and more preferably 6 mm or less, in a plan view of the wiring sheet 100. Furthermore, the width of this electrode is preferably 0.1 mm or more. When at least one electrode is a metal wire, the width of the electrode is the diameter of the metal wire. When two or more metal wires are used, the width of one electrode refers to the sum of the diameters of the individual metal wires when the wires are arranged side by side, and the major axis of the bundle in a plan view when the metal wires are bundled.

[0073] The thickness of electrode 4 is preferably 2 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. The thickness of electrode 4 is preferably 200 μm or less, more preferably 150 μm or less, even more preferably 100 μm or less, and particularly preferably 75 μm or less. If the thickness of electrode 4 is within the above range, the electrical conductivity will be high and the resistance will be low, and the resistance value with respect to the wiring body 2 can be kept low. In addition, sufficient strength as an electrode can be obtained. If the electrode is a metal wire, the thickness of the electrode is the diameter of the metal wire.

[0074] (Uses of wiring sheets, etc.) The wiring sheet 100 according to this embodiment can be suitably used, for example, as a surface heater. In this case, examples of applications for the surface heater include defoggers and defrosters for window glass.

[0075] [Manufacturing method for wiring sheets] The wiring sheet 100 according to this embodiment can be manufactured, for example, by the wiring sheet manufacturing method according to this embodiment described below. The method for manufacturing a wiring sheet according to this embodiment comprises the steps of: forming a first resin layer 3 on a first substrate 1 to produce a first resin sheet 10 (first step); forming a second resin layer 5 on a second substrate 6 to produce a second resin sheet 20 (second step); attaching a conductive wire 21 to the first resin layer 3 of the first resin sheet 10 to form a wiring body 2 (third step); forming a pair of electrodes 4 on the conductive wire 21 (fourth step); and laminating the second resin sheet 20 on the pair of electrodes 4 such that the first resin layer 3 of the first resin sheet 10 and the second resin layer 5 of the second resin sheet 20 face each other (fifth step).

[0076] In the first step, a first resin layer 3 is formed on the first substrate 1 to produce the first resin sheet 10 shown in Figure 4(A). Specifically, an adhesive for forming the first resin layer 3 is applied to the first substrate 1 to form a coating film. Next, the coating film is dried to form the first resin layer 3.

[0077] In the second step, a second resin layer 5 is formed on the second substrate 6 to produce the second resin sheet 20 shown in Figure 4(B). Specifically, an adhesive for forming the second resin layer 5 is applied to the second substrate 6 to form a coating film. Next, the coating film is dried to form the second resin layer 5.

[0078] In the third step, as shown in Figure 4(C), a conductive wire 21 is attached to the first resin layer 3 of the first resin sheet 10 to form a wiring body 2. Specifically, conductive linear bodies 21 are arranged on the first resin layer 3 to form a wiring body 2. For example, with the first resin sheet 10 placed on the outer circumferential surface of the drum member, the conductive linear bodies 21 are attached to the first resin layer 3 while adjusting the distance traveled in the drum axis direction, the travel speed, and the acceleration, as well as the forward and reverse rotation of the drum. This forms a wiring body 2 comprising conductive linear bodies 21 with a predetermined pattern, and is placed on the first resin layer 3. In this way, a wiring body film is obtained in which the wiring body 2 is formed on the first resin layer 3 of the first resin sheet 10.

[0079] In the fourth step, as shown in Figure 4(D), a pair of electrodes 4 are formed on the conductive wire 21. Specifically, a pair of electrodes 4 are formed at both ends of the conductive linear body 21 of the wiring film obtained in the third step.

[0080] In the fifth step, as shown in Figure 4(E), the second resin sheet 20 is laminated on the pair of electrodes 4 such that the first resin layer 3 of the first resin sheet 10 and the second resin layer 5 of the second resin sheet 20 face each other. Specifically, the second resin sheet 20 is laminated onto the wiring film with electrodes 4 obtained in the fourth step, such that the first resin layer 3 of the first resin sheet 10 and the second resin layer 5 of the second resin sheet 20 face each other. For the lamination method, for example, lamination can be used. In this manner, the wiring sheet 100 can be manufactured.

[0081] [Effects of the Embodiment] According to this embodiment, the following effects can be achieved. (1) According to this embodiment, it is possible to produce a wiring sheet 100 that can suppress the generation of air bubbles around conductive wires and has excellent moisture heat resistance. (2) According to this embodiment, the conductive linear body 21 and the electrode 4 can be sealed in the first resin layer 3 and the second resin layer 5, and humid heat resistance can be ensured. (3) According to this embodiment, both sides of the wiring body 2 can be protected by the first base material 1 and the second base material 6. (4) According to this embodiment, when forming the wiring body 2 on the first resin layer 3, the conductive wire 21 can be easily attached to the first resin layer 3 with an adhesive. Therefore, a wiring body 2 comprising a conductive wire 21 having a predetermined pattern can be easily formed.

[0082] [Variations of the Embodiment] The present invention is not limited to the embodiments described above, and any modifications or improvements that can achieve the objectives of the present invention are included in the present invention. For example, in the above-described embodiment, the wiring sheet 100 alone can be used independently as a planar heater, but the invention is not limited to this. For example, a third resin layer (not shown), which may contain an adhesive, may be provided on the second base material 6 of the wiring sheet 100. This third resin layer allows the wiring sheet 100 to be attached to a substrate (not shown) for use. Furthermore, in order to adhere the wiring 2 to the adherend (not shown), a third resin layer (not shown) may be provided on the side of the first substrate 1 or the second substrate 6 opposite to the first resin layer 3 or the second resin layer 5. In particular, it is preferable to provide it on the side of the second substrate 6 opposite to the second resin layer 5. Also, the third resin layer may be the same as both or either of the first resin layer 3 or the second resin layer 5, or it may be different from both the first resin layer 3 or the second resin layer 5. [Examples]

[0083] The present invention will be described in more detail below with reference to examples. The present invention is not limited to these examples. Unless otherwise specified, the mixing ratios expressed in parts by mass refer to the ratio of solid content.

[0084] [Preparation Example 1] A pressure-sensitive adhesive coating solution was obtained by mixing 100 parts by mass of an acrylic copolymer (2-ethylhexyl acrylate (2EHA) / vinyl acetate (VAc) / acrylic acid (AA) = 74 / 24 / 2 (mass ratio), weight-average molecular weight (Mw): 600,000) with 0.15 parts by mass of aluminum tris (acetylacetonate) as a crosslinking agent, diluting with toluene, and stirring uniformly. The storage modulus of the dried film of this pressure-sensitive adhesive, measured at 23°C under the following conditions, was 4.7 × 10⁻⁶. 4 It was Pa.

[0085] [Preparation Example 2] A pressure-sensitive adhesive coating solution was obtained by mixing 100 parts by mass of an acrylic copolymer (weight-average molecular weight (Mw): 410,000) having constituent units derived from raw material monomers consisting of an acrylic resin (n-butyl acrylate (BA) / acrylic acid (AA) = 90 / 10 (mass ratio)) with 0.74 parts by mass of aluminum tris (acetylacetonate) as a crosslinking agent, diluting with toluene, and stirring uniformly. The storage modulus of the dried film of this pressure-sensitive adhesive, measured at 23°C under the following conditions, was 1.4 × 10⁻⁶. 5 It was Pa.

[0086] [Example 1] A roll-shaped first adhesive film measuring 400 mm x 1000 mm is provided, with a 25 μm thick first resin layer (pressure-sensitive adhesive obtained in Preparation Example 1) on a 150 μm thick first base material made of polyurethane (manufactured by Nippon Matai Co., Ltd., product name "Esmar URSPPX #15PFT50X"), and a gold-plated tungsten wire (diameter: 25 μm, volume resistivity 5.5 x 10) as the wire. -8A wire (Ω·m) was prepared. The wire wound on the bobbin was attached to the surface of the first resin layer of the first adhesive film located near the end of the drum component. The wire was then pressed with a nip roll while being fed out, and the drum was rotated in the forward direction while moving in the axial direction of the drum to form a wiring structure as shown in Figure 1, in which eight wires were arranged in a straight line at 5 mm intervals. After that, a metal wire wiring sheet was produced by laminating it with a 38 μm thick release film (Lintec Corporation, product name "SP-PET382150"). Next, a second adhesive film measuring 400 mm × 1000 mm was prepared, with a second polyurethane substrate (manufactured by Nippon Matai Co., Ltd., product name "Esmar URSPPX #15PFT50X") having a thickness of 150 μm, on which a second resin layer consisting of a 20 μm thick second resin layer (pressure-sensitive adhesive obtained in Preparation Example 1), a 45 μm thick third resin layer (pressure-sensitive adhesive obtained in Preparation Example 1), and a release agent layer was provided. Next, the release film was peeled off the wiring film, electrodes (thickness: 60 μm, width: 5 mm, length: 10 cm) were attached to both ends of the wire, and the second adhesive film was placed on top of that with the second resin layer facing inward. The wiring sheet was then manufactured by vacuum lamination (Nikkomar Materials Co., Ltd., product name "Vacuum Laminator V-130", pressure 0.5 MPa, temperature 60°C, lamination time 120 seconds).

[0087] [Examples 2-4 and Comparative Examples 1-2] Except for changing the diameter and pattern of the conductive linear body, the thickness and type of the first resin layer, the thickness and type of the second resin layer, and the sum of the thicknesses of the first and second resin layers as shown in Table 1, a wiring film and a planar heating element were manufactured in the same manner as in Example 1. In Example 3, an electrode (size: 2.5 cm x 0.5 cm) was used.

[0088] [Evaluation of wiring sheets] The wiring sheets obtained in each example were evaluated as follows. The results are shown in Table 1.

[0089] [Measurement of resistance change rate] A resistance meter (manufactured by HIOKI E.E. CORPORATION, product name "RM3545") was connected to the electrodes, and the resistance value (R1) of the wiring sheet was measured. After leaving the wiring sheet undisturbed for 1000 hours in a humid heat environment at 85°C and 85RH%, the resistance meter was connected to the electrodes again, and the resistance value (R2) of the wiring sheet was measured. Subsequently, the rate of change in resistance values ​​(unit: %) between R1 and R2 was calculated using the following formula (F1). The smaller this rate of change in resistance value, the better the humid heat resistance of the wiring sheet. Resistance change rate = [(R2-R1) / R1] × 100 (%) ···(F1)

[0090] [Evaluation of bubbles around conductive wires] The area around the conductive wires of the wiring sheet was observed using a digital microscope, and the size of the air bubbles around the conductive wires was measured.

[0091] [Measurement of storage modulus] A cylindrical test sample with a diameter of 8 mm and a thickness of 1 mm was prepared from the same composition as the composition forming the layer to be measured. The storage modulus of the test sample was measured using a viscoelasticity measuring device (Anton Paar, device name "MCR300") with an 8 mm diameter parallel plate as the measuring fixture, under the following conditions: start temperature -20°C, end temperature 150°C, heating rate 3°C / min, shear strain 0.05%, and frequency 1 Hz.

[0092] [Table 1]

[0093] As shown in Table 1, the wiring sheets obtained in Examples 1 to 4 showed good resistance change rates and evaluation results for air bubbles around conductive wires. From this, it was confirmed that the wiring sheet according to the present invention can suppress the generation of air bubbles around conductive wires and has excellent resistance to humid heat. [Explanation of Symbols]

[0094] 1...First base material, 2, 2A, 2B...Wiring body, 21...Conductive wire, 211...Bent part, 3...First resin layer, 4...Electrode, 5...Second resin layer, 6...Second base material, 10...First resin sheet, 20...Second resin sheet, 100...Wiring sheet.

Claims

1. A wiring body comprising a conductive linear body, A pair of electrodes in direct contact with the conductive linear body, A first resin layer that directly or indirectly supports the wiring assembly, A first substrate that directly or indirectly supports the first resin layer, A second resin layer that directly or indirectly supports the wiring assembly, The invention comprises a second substrate that directly or indirectly supports the second resin layer, The first substrate, the first resin layer, the wiring body, the electrode, the second resin layer, and the second substrate are arranged in this order in the thickness direction. The sum of the thickness of the first resin layer and the thickness of the second resin layer is equal to or greater than the diameter of the conductive linear body. Wiring sheet.

2. In the wiring sheet according to claim 1, The storage moduli of the first resin layer and the second resin layer at 23°C are, respectively, 1.0 × 10⁻⁶. ４ Pa or more, 5.0×10 ６ It is less than or equal to Pa. Wiring sheet.

3. In the wiring sheet according to claim 1 or claim 2, The thicknesses of the first resin layer and the second resin layer are 5 μm or more and 100 μm or less, respectively. Wiring sheet.

4. In the wiring sheet according to claim 1 or claim 2, The wiring body has a structure in which a plurality of the conductive linear bodies are arranged at intervals. Wiring sheet.

5. In the wiring sheet according to claim 1 or claim 2, The conductive linear body has a pattern formed in plan view that has at least one bent portion. Wiring sheet.

6. In the wiring sheet according to claim 5, The wiring consists of only one conductive wire-shaped body. Wiring sheet.

7. In the wiring sheet according to claim 5, The wiring body comprises two or more conductive linear bodies. Wiring sheet.

8. A method for manufacturing a wiring sheet according to claim 1 or claim 2, A step of forming the first resin layer on the first substrate to produce a first resin sheet, A step of forming the second resin layer on the second substrate to produce a second resin sheet, The steps include: attaching the conductive wire-shaped body to the first resin layer of the first resin sheet to form the wiring body; The steps include forming the pair of electrodes on the conductive wire-shaped body, The process includes a step of laminating the second resin sheet on the pair of electrodes such that the first resin layer of the first resin sheet and the second resin layer of the second resin sheet face each other. A method for manufacturing wiring sheets.

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