Wiring sheet

Abstract

To provide a wiring sheet capable of suppressing temperature unevenness within the plane of the wiring sheet and having excellent curved surface lamination properties.SOLUTION: A wiring sheet 100 includes a wiring body 2 including conductive linear bodies 21 on which, in a plan view, a pattern having at least one bent portion 211 is formed, a pair of electrodes 4 in direct contact with the conductive linear bodies 21, and a first resin layer 3 that directly or indirectly supports the wiring body 2. The wiring body 2 includes two or more of the conductive linear bodies 21. The conductive linear bodies 21 are arranged at intervals inside the conductive linear bodies 21 in a plan view. When the number of conductive linear bodies 21 is N and the resistance value of the x-th conductive linear body 21 counting from the outside is rx, the condition shown in the following mathematical formula (F1) is satisfied: r1<rN (F1).SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] For example, Patent Document 1 describes a wiring sheet that can be used for a sheet heater, which includes a pseudo-sheet structure in which a plurality of conductive linear elements are arranged at intervals, a pair of electrodes, and a first power supply portion and a second power supply portion provided on each of the electrodes. This wiring sheet is designed so that the conductive linear elements located farther away from the first power supply portion and the second power supply portion have a lower resistance value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2021 / 187361 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the wiring sheet described in Patent Document 1, it is possible to suppress temperature unevenness within the plane of the wiring sheet. However, the wiring sheet described in Patent Document 1 does not require electrodes to be arranged in opposing positions. In such cases, it is necessary to increase the area of ​​the electrodes, which is not a problem when the wiring sheet is flat, but when the wiring sheet is attached to a curved surface, it is likely to cause bubbles, wrinkles, or undulations. In other words, if the area of ​​the electrodes can be reduced, a wiring sheet can be obtained that is easy to remove bubbles and wrinkles and has excellent curved surface attachment properties.

[0005] An object of the present invention is to provide a wiring sheet that can suppress temperature unevenness within the plane of the wiring sheet and has excellent curved surface attachment properties. [Means for solving the problem]

[0006] [1] A wiring body including a conductive linear body on which a pattern having at least one bent portion is formed in a plan view; a pair of electrodes in direct contact with the conductive linear body; a first resin layer that directly or indirectly supports the wiring body; Equipped with the wiring body includes two or more of the conductive linear bodies, and the conductive linear bodies are arranged at intervals inside the conductive linear bodies in a plan view, The number of the conductive linear bodies is N, and the resistance value of the x-th conductive linear body counted from the outside is r x When this is the case, the condition shown in the following formula (F1) is satisfied. Wiring sheet. r1 <r N ···(F1)

[0007] [2] In the wiring sheet according to [1], Furthermore, a substrate that directly or indirectly supports the wiring body; a second resin layer provided between the adherend and the wiring sheet, the substrate, the first resin layer, the wiring body, the electrode, and the second resin layer are provided in this order in the thickness direction of the wiring sheet; Wiring sheet.

[0008] [3] In the wiring sheet according to [1] or [2], Furthermore, the condition shown in the following formula (F2) is satisfied: Wiring sheet. 1.02≦r N / r1≦2.00 (F2)

[0009] [4] The wiring sheet according to any one of [1] to [3], The resistance value of the nth conductive wire counting from the outside is r n , the resistance value of the (n+1)th conductive linear body counting from the outside is r n+1 When this is the case, the condition shown in the following formula (F3) is satisfied. Wiring sheet. r n ≦r n+1 (F3)

[0010] [5] The wiring sheet according to any one of [1] to [4], The thickness of the first resin layer is 5 μm or more and 100 μm or less. Wiring sheet.

[0011] [6] The wiring sheet according to any one of [1] to [5], The storage modulus of the first resin layer at 23°C is 1.0 × 10 4 Pa or more, 5.0×10 6 Pa or less, Wiring sheet. [Effects of the Invention]

[0012] According to one aspect of the present invention, it is possible to provide a wiring sheet that can suppress temperature unevenness within the plane of the wiring sheet and has excellent curved surface attachment properties. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram illustrating a wiring sheet according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing the II-II cross section of FIG. [Figure 3] FIG. 2 is a cross-sectional view showing the cross section III-III of FIG. [Figure 4] 10A and 10B are schematic diagrams showing modified aspects of the wiring body in the embodiment of the present invention. [Figure 5] 10 is a schematic diagram showing a modified aspect (an aspect corresponding to a comparative example) of the wiring body in the embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] [Embodiment] The present invention will be described below with reference to the drawings, taking an embodiment as an example. The present invention is not limited to the content of the embodiment. In the drawings, some parts are illustrated enlarged or reduced in size for ease of explanation.

[0015] [Wiring sheet] As shown in Figures 1, 2, and 3, the wiring sheet 100 of this embodiment includes a substrate 1, a wiring body 2, a first resin layer 3, a pair of electrodes 4, and a second resin layer 5. The wiring body 2 includes a conductive linear body 21 in which a pattern having at least one bent portion 211 is formed in a plan view. The first resin layer 3 directly or indirectly supports the wiring body 2. As shown in FIG. 2, the electrodes 4 are provided on the first resin layer 3 and are in direct contact with the conductive linear body 21. The pair of electrodes 4 can be electrically connected to a power source (not shown). Wiring sheet 100 can be used by being attached to an adherend (not shown) via second resin layer 5 or another pressure-sensitive adhesive layer (not shown). The adherend may have a curved surface.

[0016] In this embodiment, the wiring body 2 includes two or more conductive linear bodies 21, and in a plan view, the conductive linear bodies 21 are arranged at intervals inside the conductive linear bodies 21. Furthermore, the number of conductive linear bodies 21 is N, and the resistance value of the x-th conductive linear body counting from the outside is r x In this case, it is necessary to satisfy the condition shown in the following formula (F1). r1 <r N ···(F1) The reasons why interconnection sheet 100 according to this embodiment can suppress temperature unevenness within the plane of interconnection sheet 100 and has excellent curved surface attachment properties are as follows. That is, in this embodiment, the contact area between the wiring body 2 and the electrode 4 is sufficient at both ends of only a small number of conductive linear bodies 21, such as two, and therefore the area of ​​the electrode 4 can be reduced. This improves the curved surface bonding ability of the wiring sheet 100. Furthermore, when conductive linear bodies 21 are arranged at intervals inside one another, the outer conductive linear bodies 21 are usually longer and therefore have a higher resistance. This reduces the heat generation of the outer conductive linear bodies 21, making it more likely to result in temperature unevenness. In contrast, in this embodiment, the condition expressed by formula (F1) is satisfied, so the heat generation of the outer conductive linear bodies 21 can be increased, and as a result, temperature unevenness within the plane of the wiring sheet 100 can be suppressed.

[0017] In this embodiment, it is further preferable to satisfy the condition shown in the following formula (F2). 1.02≦r N / r1≦2.00 (F2) r N If the value of / r1 is 1.02 or more, the heat generation temperature of the conductive linear body 21 located on the outer side can be further increased, and temperature unevenness within the plane can be further suppressed. N If / r1 is 2.00 or less, the heat generation temperature of the conductive linear body 21 located on the outer side will not be too high, and temperature unevenness within the plane can be further suppressed. N The value of / r1 is more preferably 1.04 or more, and even more preferably 1.05 or more. N The value of / r1 is more preferably 1.80 or less, and even more preferably 1.60 or less.

[0018] The resistance value of the conductive linear body 21 can be set by any known method, and can be adjusted by changing the material, cross-sectional area, length, etc., for example. 1, the resistance value of the outer conductive linear body 21 can be reduced by making the length of the outer conductive linear body 21 shorter than the length of the inner conductive linear body 21. Furthermore, the resistance value can be reduced by increasing the electrical conductivity or cross-sectional area of ​​the outer conductive linear body 21.

[0019] In this embodiment, as shown in Fig. 2, the wiring sheet 100 is preferably provided with a substrate 1, a first resin layer 3, a conductive linear member 21, an electrode 4, and a second resin layer 5 in this order. Such a wiring sheet 100 can be used by being attached to an adherend, and therefore the surface of the wiring member 2 is covered with the substrate 1, thereby protecting the wiring member 2. Note that in conventional wiring sheets, the technical idea of ​​protecting the wiring member 2 with the substrate has not been to protect the wiring member 2, and instead the wiring member 2 has been protected not by the substrate but by a separate protective film or the like.

[0020] (base material) The substrate 1 can directly or indirectly support the wiring body 2. The substrate 1 does not necessarily have to be provided. The substrate 1 is a member that is provided as needed. Examples of materials for the substrate 1 include resin, paper, metal, nonwoven fabric, cloth, and glass. Among these, resin or glass is preferred from the viewpoint of strength and ease of handling. Examples of resins used for the substrate 1 include polyurethane, polyester, polyethylene, polypropylene, polystyrene, polycarbonate, and polyacetal.

[0021] The thickness of the substrate 1 is preferably 10 μm or more, more preferably 18 μm or more, and even more preferably 26 μm or more. The thickness of the substrate 1 is preferably 10 mm or less, more preferably 1 mm or less, and even more preferably 300 μm or less. When the thickness of the substrate 1 is within the above range, excellent strength and the like can be obtained.

[0022] (Wiring body) The wiring body 2 includes a conductive linear body 21 in which a pattern having at least one bent portion 211 is formed in a plan view. In this embodiment, as shown in Fig. 1, the wiring body 2 includes two or more conductive linear bodies 21, and the conductive linear bodies 21 are required to be arranged at intervals inside each other in a plan view. Furthermore, the wiring body 2 preferably has a pattern that can be drawn in a single stroke in a plan view.

[0023] As shown in FIG. 1, the wiring body 2 includes two conductive linear bodies 21 formed in a fork-shaped pattern. That is, the wiring body 2 includes an outer conductive linear body 21 and an inner conductive linear body 21 located inside the outer conductive linear body 21. The widthwise spacing of the forks is 5 mm and 4 mm, respectively. Here, the penetration length of the fork tip portion of the fork-shaped pattern is shorter for the outer conductive linear body 21 than for the inner conductive linear body 21. Therefore, the length of the outer conductive linear body 21 is shorter than the length of the inner conductive linear body 21. As a result, r N When a gold-plated tungsten wire with a diameter of 35 μm is used, the value of / r1 is 1.06, which satisfies the condition shown in the above formula (F1). Furthermore, if the pair of electrodes 4 is considered to be on the lower side, the conductive linear body 21 extends upward from the electrode 4 located at the lower center left, bends at a right angle at bend 211, extends to the left, bends at a right angle at bend 211 again, and extends upward. Then, it bends at a right angle at bend 211, extends to the right, bends at the next bend 211 again, and extends downward. In this manner, one fork tip is formed. Subsequently, as the conductive linear body 21 is formed into a fork-shaped pattern, it reaches the electrode 4 located at the lower center right. Bending at a right angle at bend 211 like this has the advantage of making it easier to form the pattern. In this case, the number of fork tips is three. The number of fork tips is not limited, but the more tips there are, the denser the pattern can be formed. The number of tip portions of the fork is preferably two or more, and more preferably three or more.

[0024] The wiring body 2 is not limited to this configuration, and may have the following configuration, for example. Another embodiment of the wiring body 2 is a wiring body 2A shown in FIG. 4(A). As shown in FIG. 4(A), the wiring body 2A includes conductive linear bodies 21 formed in a rectangular pattern and conductive linear bodies 21 formed in a fork-shaped pattern inside the rectangular pattern. The fork width spacing is 4 mm. Here, the conductive linear bodies 21 located on the inside are fork-shaped patterns and are longer than those in a rectangular pattern because they are prone to bending. Therefore, the length of the conductive linear bodies 21 located on the outside is shorter than the length of the conductive linear bodies 21 located on the inside. As a result, r N When a gold-plated tungsten wire with a diameter of 40 μm is used, the value of / r1 is 1.50, which satisfies the condition shown in the above formula (F1). Conductive linear body 21 formed in a rectangular pattern extends upward from electrode 4 located at the bottom center left in Figure 4(A), bends at a right angle at bend 211, extends to the left, bends again at a right angle at bend 211 and extends upward, bends again at a right angle at bend 211 and extends to the right, bends again at a right angle at bend 211 and extends downward. In this way, conductive linear body 21 reaches electrode 4 located at the bottom center right while being formed in a rectangular pattern. The conductive linear body 21 formed in the fork-shaped pattern is as described above. In Fig. 4(A), the number of fork tips is three.

[0025] Another embodiment of the wiring body 2 is wiring body 2B shown in FIG. 4(B). As shown in FIG. 4(B), wiring body 2B includes three conductive linear bodies 21 formed in a fork-shaped pattern. The forks are spaced 5 mm, 4 mm, and 3 mm apart in the width direction. That is, wiring body 2B includes a first conductive linear body 21 counting from the outside, a second conductive linear body 21 counting from the outside that is located inside it, and a third conductive linear body 21 counting from the outside that is located further inside. As such, the greater the number of conductive linear bodies 21, the easier it is to cover the plane of wiring sheet 100, thereby improving the temperature uniformity of wiring sheet 100. Here, the lengths of the first conductive linear body 21, the second conductive linear body 21, and the third conductive linear body 21 increase in this order. As a result, r N When a gold-plated tungsten wire with a diameter of 10 μm is used, the value of / r1 is 1.10, which satisfies the condition shown in the above formula (F1). In the wiring body 2B, the resistance value of the n-th conductive linear body counted from the outside is r n , the resistance value of the (n+1)th conductive linear body counting from the outside is r n+1 This is preferable in that the condition shown in the following formula (F3) is satisfied. r n ≦r n+1(F3) When the condition shown in formula (F3) is satisfied, the heat generated by conductive linear body 21 can be reduced toward the inside where heat tends to be trapped, and temperature unevenness within the plane of wiring sheet 100 can be further suppressed. The conductive linear body 21 formed in the fork-shaped pattern is as described above. In Fig. 4(B), the number of fork tips is three.

[0026] Another embodiment of the wiring body 2 is the wiring body 2C shown in FIG. 5(A). The wiring body 2C includes two conductive linear bodies 21 formed in a fork-shaped pattern. The widthwise spacing of the forks is 5 mm and 4 mm, respectively. That is, the wiring body 2C includes an outer conductive linear body 21 and an inner conductive linear body 21 located inside the outer conductive linear body 21. Here, the penetration length of the fork tip portion of the fork-shaped pattern is the same for the outer conductive linear body 21 and the inner conductive linear body 21. Therefore, the length of the outer conductive linear body 21 is longer than the length of the inner conductive linear body 21. As a result, r N The value of / r1 was 0.90 when a gold-plated tungsten wire with a diameter of 35 μm was used, and 0.95 when a gold-plated tungsten wire with a diameter of 40 μm was used, which does not satisfy the condition indicated by formula (F1).

[0027] Another embodiment of the wiring body 2 is the wiring body 2D shown in FIG. 5(B). The wiring body 2D includes two conductive linear bodies 21 formed in a fork-shaped pattern in which the central convex part is larger than the convex parts at both ends. The widthwise spacing of the forks is 5 mm and 4 mm, respectively. That is, the wiring body 2D includes a conductive linear body 21 located on the outside and a conductive linear body 21 located on the inside thereof. Here, the penetration length of the fork tip parts of the fork-shaped pattern is the same for the conductive linear body 21 located on the outside and the conductive linear body 21 located on the inside. Therefore, the length of the conductive linear body 21 located on the outside is longer than the length of the conductive linear body 21 located on the inside. As a result, r N When a gold-plated tungsten wire with a diameter of 40 μm was used, the value of / r1 was 0.97, which does not satisfy the condition indicated by the above formula (F1).

[0028] 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 It is more preferable that the resistance is Ω·m or more, and 1.0×10 -8 The volume resistivity of the conductive linear body 21 is more preferably 1.0×10 -3 It is preferable that the resistance is Ω·m or less, and 1.0×10 -4 It is more preferable that it is 5.0×10 Ω·m or less. -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 to a portion 40 mm from the end, and the resistance of the end and the 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.

[0029] 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 first resin layer 3, the cross-sectional shape of the conductive linear body 21 is preferably elliptical or circular.

[0030] 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 5 μm or more, and even more preferably 9 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 40 μm or less. When the cross section of the conductive linear body 21 is elliptical, it is preferable that the major axis is in the same range as the diameter D described above.

[0031] 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.

[0032] The conductive linear body 21 may be formed by any method, such as etching, screen printing, or inkjet printing. Preferably, the conductive linear body 21 is a linear body containing a metal wire (hereinafter also referred to as a "metal wire linear body"). Metal wires have high thermal conductivity, high electrical conductivity, and easy handling. Metal wire linear bodies can significantly reduce resistance, and even if the diameter of the metal wire linear body is extremely small, the current required for heating the wiring sheet 100 can be passed through the metal wire linear body. This makes the conductive linear body 21 less visible. In other words, using a metal wire linear body as the conductive linear body 21 can reduce the resistance of the wiring body 2 while improving light transmittance. Furthermore, the wiring sheet 100 can easily generate heat quickly. Furthermore, as described above, it is easy to obtain linear bodies with a small diameter. The conductive linear body 21 may be a metal wire linear body, a linear body containing carbon nanotubes, or a linear body in which a thread is coated with a conductive material.

[0033] The metal wire linear body may be a linear body made of a single metal wire, or may be a linear body made of a plurality of twisted metal wires. Examples of metal wires include wires containing metals such as copper, aluminum, tungsten, iron, molybdenum, nickel, titanium, silver, and gold, or alloys containing two or more metals such as stainless steel, carbon steel, brass, phosphor bronze, zirconium-copper alloy, beryllium copper, iron-nickel, nichrome, nickel-titanium, Kanthal, Hastelloy, and rhenium-tungsten. The metal wire may be plated with gold, tin, zinc, silver, nickel, chromium, nickel-chromium alloy, or solder, or may be surface-coated with a carbon material or polymer, as described below. Wires containing one or more metals selected from tungsten and molybdenum, and alloys containing these, are particularly 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 of the metal wire is reduced, making it easier to make the metal wire less noticeable. Furthermore, when the metal wire is coated with a carbon material, metal corrosion is also suppressed. Examples of the carbon material that can be used to coat 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.

[0034] The conductive linear body 21 may be a linear body in which a conductive coating is applied to the thread. Examples of the thread include threads spun from resins such as nylon or polyester. Examples of the thread include threads made of metal fiber, carbon fiber, or ion-conductive polymer fiber. Examples of the conductive coating include coatings made 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 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.

[0035] (resin layer) The first resin layer 3 directly or indirectly supports the wiring body 2. The second resin layer 5 is provided so as to cover the wiring body 2. The first resin layer 3 and the second resin layer 5 are preferably layers containing an adhesive. For example, when forming the wiring body 2 on the first resin layer 3, the adhesive makes it easy to attach the conductive linear body 21 to the first resin layer 3. The second resin layer 5 also allows the wiring sheet 100 to be attached to an adherend.

[0036] The storage modulus of the first resin layer 3 at 23°C is 1.0 × 10 4 Pa or more, 5.0×10 6 Pa or less, and 2.0 × 10 4 Pa or more, 1.0×10 6 Pa or less is more preferable, and 3.0 × 10 4 Pa or more, 5.0×10 5 It is more preferable that the storage modulus is equal to or less than 100 Pa. If the storage modulus is within the above range, the conductive linear body 21 can be appropriately embedded in the first resin layer 3 when the wiring body 2 is formed on the first resin layer 3. The storage modulus of the second resin layer 5 at 23°C is not particularly limited. The storage modulus of the second resin layer 5 at 23°C is 1.0×10 4 Pa or more, 5.0×10 6 Pa or less, and 4 Pa or more, 1.0×10 6 Pa or less, and 4Pa or more, 5.0×10 5 It may be less than Pa.

[0037] The thickness of the first resin layer 3 is not particularly limited. The thickness of the first resin layer 3 may be equal to or greater than the diameter D of the conductive linear member 21, or may be less than the diameter D of the conductive linear member 21. When the thickness of the first resin layer 3 is equal to or greater than the diameter D of the conductive linear member 21, the wiring body 2 can be contained within the first resin layer 3. When the thickness of the first resin layer 3 is less than the diameter D of the conductive linear member 21, the wiring body 2 is exposed from the first resin layer 3. Furthermore, when the wiring body 2 is exposed from the first 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 first resin layer 3 is preferably equal to or greater than 5 μm, more preferably equal to or greater than 10 μm, and even more preferably equal to or greater than 20 μm. The thickness of the first resin layer 3 is preferably equal to or less than 100 μm, more preferably equal to or less than 70 μm, and even more preferably equal to or less than 50 μm. The thickness of the second resin layer 5 is not particularly limited. The thickness of the second resin layer 5 is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. The thickness of the first resin layer 3 is preferably 100 μm or less, more preferably 70 μm or less, and even more preferably 50 μm or less. If the thickness is within the above range, the conductive linear member 21 can be sealed in the resin, and electrical insulation can be ensured.

[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. 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 pressure-sensitive adhesives include polymers containing structural units derived from alkyl (meth)acrylates having a linear alkyl group or a branched alkyl group, and acrylic polymers containing structural units derived from (meth)acrylates having a cyclic structure. Here, "(meth)acrylate" is used as a term that refers to both "acrylate" and "methacrylate," and the same applies to other similar terms.

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

[0041] From the viewpoint of increasing the storage modulus, the first resin layer 3 and the second resin layer 5 are preferably layers made of a cured product of a curable adhesive. Such first resin layer 3 and second resin layer 5 can stabilize the resistance value of the wiring body 2. That is, the first resin layer 3 and second resin layer 5 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. Examples of curable adhesives include thermosetting adhesives that are cured by heat, and energy ray-curable 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 using energy rays.

[0042] The curable adhesive preferably contains a thermosetting resin. Thermosetting resins are not particularly limited, and specific examples include epoxy resins, phenolic resins, melamine resins, urea resins, polyester resins, urethane resins, acrylic resins, benzoxazine resins, phenoxy resins, amine compounds, and acid anhydride compounds. These can be used alone or in combination of two or more. Among these, epoxy resins, phenolic resins, melamine resins, urea resins, amine compounds, and acid anhydride compounds are preferred from the viewpoint of suitability for curing using an imidazole curing catalyst. In particular, epoxy resins, phenolic resins, mixtures thereof, or mixtures of epoxy resins with at least one selected from the group consisting of phenolic resins, melamine resins, urea resins, amine compounds, and acid anhydride compounds are preferred from the viewpoint of exhibiting excellent curability, and epoxy resins are preferred.

[0043] As the epoxy resin, a cyclic one such as an aromatic epoxy resin or an alicyclic epoxy resin is preferred from the viewpoint of increasing the storage modulus of the first resin layer 3 and the second resin layer 5. An epoxy resin having a flexible segment such as an oxyalkylene chain tends to decrease the storage modulus of the first resin layer 3 and the second resin layer 5.

[0044] The energy ray-curable adhesive preferably contains an energy ray-curable resin, such as a compound having at least one polymerizable double bond in the molecule, and preferably an acrylate compound having a (meth)acryloyl group.

[0045] 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. Examples of the (meth)acrylate include (meth)acrylates containing a chain 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, more preferably 300 or more. The weight average molecular weight is preferably 30,000 or less, more preferably 10,000 or less. The weight average molecular weight in this specification is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0047] The adhesive may contain one kind of energy ray curable resin or two or more kinds of energy ray curable resins. When two or more kinds of energy ray curable resins are contained, the combination and ratio thereof can be selected arbitrarily.

[0048] 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.

[0049] Examples of the photopolymerization initiator include photoradical polymerization initiators such as benzophenone, acetophenone, benzoin, benzoin methyl ether, 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.

[0050] In addition to photoradical polymerization initiators, photocationic polymerization initiators can also be used as photopolymerization initiators. A photocationic polymerization initiator is a compound that generates cationic species when irradiated with energy rays, thereby initiating 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 generation source.

[0051] Examples of the photocationic polymerization initiator include sulfonium salt compounds, iodonium salt compounds, phosphonium salt compounds, ammonium salt compounds, antimonate 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.

[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 the phosphonium salt compound include tri-n-butyl(2,5-dihydroxyphenyl)phosphonium bromide and hexadecyltributylphosphonium chloride.

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

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

[0057] 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.

[0058] In addition to the above-mentioned thermal radical polymerization initiators, examples of the thermal polymerization initiator include thermal cationic polymerization initiators. The thermal cationic polymerization initiator is a compound that can generate cationic species that initiate polymerization by heating. Examples of the thermal cationic polymerization initiator include sulfonium salts, quaternary ammonium salts, phosphonium salts, diazonium salts, and iodonium salts. Among these, sulfonium salts are preferred from the viewpoints of easy availability and the ease with which a product with superior adhesion and transparency can be obtained.

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

[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, etc. Examples of iodonium salts include diphenyliodonium hexafluoroarsinate, bis(4-chlorophenyl)iodonium hexafluoroarsinate, and phenyl(4-methoxyphenyl)iodonium hexafluoroarsinate, etc.

[0062] 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.

[0063] When a thermosetting resin is used, a curing catalyst such as an imidazole-based curing catalyst may be used.

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

[0065] These flexibility-adjusting components can be used alone 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 the energy ray-curable resin and 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, 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 within the above-mentioned range. Furthermore, 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 first resin layer 3 and the second resin layer 5 tends to be too high.

[0067] In this embodiment, the curable adhesive preferably does not contain a filler. When the adhesive does not contain a filler, the storage modulus at 23°C of the first resin layer 3 and the second resin layer 5 can be prevented from becoming too high. However, the curable adhesive may contain a filler to the extent that the storage modulus at 23° C. of the first resin layer 3 and the second resin layer 5 can be adjusted to fall within the above 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 obtained by spheroidizing inorganic powders, single-crystal fibers, and glass fibers. Among these, silica filler and alumina filler are preferred. One type of filler may be used alone, or two or more types may be used in combination.

[0069] 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, antifungal agents, plasticizers, antifoaming agents, and wettability adjusters.

[0070] (electrode) The electrodes 4 are used to supply current to the conductive linear body 21. The electrodes 4 are in pair. The electrodes 4 are in direct contact with the conductive linear body 21. The electrodes 4 are arranged so as to be electrically connected to both ends of the conductive linear body 21. The electrode 4 can be formed using a known electrode material. Examples of the electrode material include a conductive paste such as silver paste, a metal foil such as copper foil, and a metal wire. When the electrode material is a metal wire, the metal wire may be one wire, but preferably two or more wires.

[0071] When the electrode material is a metal foil or metal wire, examples of the metal for the metal foil or metal wire include 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. The metal foil or metal wire may also be plated with gold, tin, zinc, silver, nickel, chromium, nickel-chromium alloy, solder, or the like.

[0072] The width of at least one of the electrodes 4 is preferably 10 mm or less, and more preferably 5 mm or less, in a plan view of the wiring sheet 100. The width of this electrode is preferably 0.1 mm or more. When at least one of the electrodes 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 metal wires when the metal wires are arranged side by side, or refers to the long diameter of the bundle of metal wires when viewed in a plan view.

[0073] The length of at least one of the electrodes 4 is preferably 30 mm or less, and more preferably 20 mm or less, in a plan view of the wiring sheet 100. The length of this electrode is preferably 1 mm or more. In this embodiment, the number of conductive linear bodies 21 is small, so the length of the electrode 4 can be short.

[0074] The thickness of the 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 the 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 the electrode 4 is within the above range, the electrical conductivity is high and the resistance is low, and the resistance value with the wiring body 2 can be kept low. Furthermore, sufficient strength as an electrode can be obtained. Note that when the electrode is a metal wire, the thickness of the electrode is the diameter of the metal wire.

[0075] (Use of wiring sheet, etc.) The wiring sheet 100 according to this 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.

[0076] (Method of manufacturing wiring sheet) There are no particular limitations on the method for manufacturing interconnect sheet 100 according to this embodiment. Interconnect sheet 100 can be manufactured, for example, as follows. First, an adhesive for forming the first resin layer 3 is applied to the substrate 1 to form a coating film. Next, the coating film is dried to create an adhesive layer. Next, conductive linear members 21 are arranged and placed on the adhesive layer to form the wiring body 2. For example, with the adhesive layer with the substrate 1 placed on the outer circumferential surface of a drum member, the conductive linear members 21 are attached to the adhesive layer while adjusting the movement distance, movement speed, and acceleration in the drum axial direction, as well as the forward and reverse rotation of the drum. This forms the wiring body 2 including conductive linear members 21 formed with a pattern having at least one bent portion 211, and the wiring body 2 is placed on the adhesive layer. In this way, a wiring body sheet in which the wiring body 2 is formed on the adhesive layer with the substrate 1 is obtained. Next, a pair of electrodes 4 is formed on both ends of conductive linear body 21 in wiring body 2 of the sheet-like conductive member. In this manner, wiring sheet 100 can be produced.

[0077] [Effects of the embodiment] According to this embodiment, the following effects can be achieved. (1) According to the present embodiment, it is possible to produce wiring sheet 100 that can suppress temperature unevenness within a plane, has excellent snow melting performance, and is excellent in curved surface attachment ability. (2) According to this embodiment, the number of conductive linear members 21 can be reduced. The contact area between wiring member 2 and electrode 4 is sufficient at both ends of a small number of conductive linear members 21, so the area of ​​electrode 4 can be reduced. Furthermore, wiring sheet 100 with excellent curved surface attachment properties can be produced. (3) According to this embodiment, when forming the wiring body 2 on the first resin layer 3, the adhesive makes it easy to attach the conductive linear body 21 to the first resin layer 3. Therefore, it is easy to form the wiring body 2 including the conductive linear body 21 on which a predetermined pattern is formed. (4) According to this embodiment, the conductive linear body 21 can be sealed in the first resin layer 3 and the second resin layer 5, ensuring electrical insulation.

[0078] [Modification of the embodiment] The present invention is not limited to the above-described embodiment, and includes modifications and improvements within the scope of achieving the object of the present invention. For example, in the above-described embodiment, the wiring sheet 100 is configured to be attached to an adherend (not shown) via the second resin layer 5 of the wiring sheet 100 or a pressure-sensitive adhesive layer (not shown) provided on the second resin layer 5, but the present invention is not limited to this. For example, a protective sheet (not shown) may be provided on the second resin layer 5 of the wiring sheet 100. In such a case, a layer (not shown) containing an adhesive may be further provided on the protective sheet, and the wiring sheet may be attached to an adherend (not shown) via this layer. [Example]

[0079] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples. Unless otherwise specified, the blending ratios shown in parts by mass are the ratios of solid content.

[0080] [Preparation Example 1] A pressure-sensitive adhesive was prepared 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 a dried film of this pressure-sensitive adhesive measured at 23°C under the following conditions was 4.7 x 10 4 It was Pa.

[0081] [Preparation Example 2] A pressure-sensitive adhesive was prepared by mixing 100 parts by mass of an acrylic copolymer (weight average molecular weight (Mw): 410,000) having structural units derived from raw material monomers consisting of 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 a dried film of this pressure-sensitive adhesive measured at 23°C under the following conditions was 1.4 x 10 5 It was Pa.

[0082] [Storage modulus measurement] A cylindrical test sample with a diameter of 8 mm and a thickness of 1 mm was prepared from the same composition as the layer to be measured. The storage modulus of the test sample was measured using a viscoelasticity measuring device (manufactured by Anton Paar, model name "MCR300") with a parallel plate of 8 mm diameter as the measuring jig at a test temperature of 23°C, a shear strain of 0.05%, and a frequency of 1 Hz.

[0083] [Example 1] A roll-shaped first adhesive film measuring 400 mm × 1000 mm was prepared, in which a 35 μm thick adhesive layer (the pressure-sensitive adhesive obtained in Preparation Example 1) was provided as a first resin layer on a 150 μm thick urethane substrate (manufactured by Nihon Matai Co., Ltd., product name "ESMER URSPPX#15PFT50X"), and a gold-plated tungsten wire (diameter: 35 μm, volume resistivity: 5.5 × 10) was used as a wire. -8A wire wound around a bobbin was attached to the surface of the adhesive layer of a pressure-sensitive adhesive film located near the end of the drum. The wire was compressed with a nip roll while being unwound, and the axial movement distance, movement speed, and acceleration, as well as the forward and reverse rotation of the drum, were adjusted to form a wiring body with a wire pattern as shown in Figure 1. This was then bonded to a 38 μm-thick release film (manufactured by Lintec Corporation, product name "SP-PET382150") using a laminator to create a wiring body sheet. Next, a second adhesive film measuring 400 mm x 1000 mm was prepared as the adherend, which had a 150 μm thick urethane substrate (manufactured by Nippon Matai Co., Ltd., product name "Esmar URSPPX#15PFT50X") on top of which a 45 μm thick adhesive layer (pressure-sensitive adhesive obtained in Preparation Example 1) was provided as the second resin layer. Next, the release film was peeled off from the wiring sheet, and electrodes (size: 1 cm x 0.5 cm) were attached to both ends of the wire. A second adhesive film was then placed on top of the electrodes with the second resin layer facing inward, and the two were bonded together using a laminator to produce a planar heating element.

[0084] [Examples 2 and 3, Comparative Examples 1 to 3] A wiring sheet and a sheet heating element were prepared in the same manner as in Example 1, except that the thickness and type of the substrate, the thickness and type of the first resin layer, the thickness and type of the second resin layer, and the diameter and pattern of the conductive linear element were changed as shown in Table 1. In Example 3, the following base materials are used. PET: 50 μm thick polyethylene terephthalate substrate (manufactured by Toyobo Co., Ltd., product name "Cosmoshine A4160")

[0085] [Wiring sheet evaluation] The wiring sheets obtained in each example were evaluated as follows, and the results are shown in Tables 2 and 3.

[0086] [Resistance measurement] The resistance value of each conductive linear body and wiring body was measured using a measuring device (manufactured by Hioki Electric Industry Co., Ltd., product name "RM3545").

[0087] [Curved surface lamination properties] The wiring sheet was cut into a size of 5 cm x 5 cm, and electrodes (gold-plated copper foil, 60 μm thick, manufactured by Mitsuya Co., Ltd.) were attached to both ends of the conductive linear bodies to prepare a wiring sheet. The size of the electrodes was 1 cm x 0.5 cm. The obtained wiring sheet was then attached by hand to a circular curved surface (diameter: 5 cm), and the presence or absence of bubbles and wrinkles (waviness) upon attachment was evaluated according to the following criteria. A: No bubbles or wrinkles (waviness) occurred around the electrodes. F: Bubbles or wrinkles (waviness) occurred around the electrodes.

[0088] [Evaluation of temperature unevenness] 12V was applied to the wiring sheet, and the surface temperature of the sheet heating element was measured after 10 minutes using a thermal camera. The temperature directly above each conductive linear element and the average temperature of the wiring were calculated.

[0089] [Snow melting performance evaluation] 10 g of snow was attached to the surface of the wiring sheet, and 12 V was applied. After 10 minutes, the surface condition of the sheet heating element was observed. A: All the snow on the heating element melted. F: Some snow remained on the surface heating element.

[0090] [Table 1]

[0091] [Table 2]

[0092] [Table 3]

[0093] As shown in Tables 2 and 3, the wiring sheets using the wiring body sheets obtained in Examples 1 to 3 had small temperature differences within the plane of the wiring sheet, good snow melting performance, and good evaluation results for curved surface adhesion. This confirms that the wiring sheet according to the present invention can suppress temperature unevenness within the plane of the wiring sheet and has excellent curved surface adhesion properties. [Explanation of symbols]

[0094] 1...substrate, 2, 2A, 2B...wiring body, 21...conductive linear body, 211...bending portion, 3...first resin layer, 4...electrode, 5...second resin layer, 100...wiring sheet.

Claims

1. a wiring body including a conductive linear body on which a pattern having at least one bent portion is formed in a plan view; a pair of electrodes in direct contact with the conductive linear body; a first resin layer that directly or indirectly supports the wiring body; Equipped with the wiring body includes two or more of the conductive linear bodies, and the conductive linear bodies are arranged at intervals inside the conductive linear bodies in a plan view, The number of the conductive linear bodies is N, and the resistance value of the x-th conductive linear body counted from the outside is r ｘ When the above formula (F1) is satisfied, the condition shown in the following formula (F1) is satisfied. Wiring sheet. r １ <r Ｎ ・・・(F1)

2. The wiring sheet according to claim 1 , Furthermore, a substrate that directly or indirectly supports the wiring body; a second resin layer provided between the adherend and the wiring sheet, the substrate, the first resin layer, the wiring body, the electrode, and the second resin layer are provided in this order in the thickness direction of the wiring sheet; Wiring sheet.

3. The wiring sheet according to claim 1 or 2, Furthermore, the condition shown in the following formula (F2) is satisfied: Wiring sheet. 1.02≦r Ｎ / r １ ≦2.00 ・・・(F2)

4. The wiring sheet according to claim 1 or 2, The resistance value of the n-th conductive linear body counted from the outside is r ｎ , the resistance value of the (n+1)th conductive linear body counted from the outside is r ｎ＋１ When this is set, the condition shown in the following formula (F3) is satisfied. Wiring sheet. r ｎ ≦r ｎ＋１ ・・・(F3)

5. The wiring sheet according to claim 1 or 2, The thickness of the first resin layer is 5 μm or more and 100 μm or less. Wiring sheet.

6. The wiring sheet according to claim 1 or 2, The storage modulus of the first resin layer at 23°C is 1.0 × 10 ４ Pa or more, 5.0×10 ６ Pa or less, Wiring sheet.

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