wiring board

Abstract

A wiring board (100) includes: a wiring body (2) including a conductive linear body (21); and a pair of electrodes (4) in direct contact with the conductive linear body (21), the conductive linear body (21) having an infrared reflectance of 0% or more and 90% or less at a wavelength of 1000 nm, and a resistance value change rate of 50% or less after being left in a damp heat environment of 85°C and 85% RH for 1000 hours.

Description

Technical Field

[0001] This invention relates to wiring boards. Background Technology

[0002] A wiring board with a wiring component is known. This wiring board can be used, for example, in materials for heat-generating textiles, components for heating various items, and heating elements in heat-generating devices such as sensors.

[0003] Patent Document 1 discloses a wiring board equipped with a contact sensor. The sensor disclosed in Patent Document 1 is a contact sensor comprising an analog sheet structure formed by multiple conductive wires arranged at intervals, a first electrode electrically connected to the conductive wires, and a second electrode disposed separately from the analog sheet structure and the first electrode, which, when viewed from above, intersects the conductive wires but does not overlap with the first electrode.

[0004] Patent Document 2 discloses a pressure-sensitive heating element having a pressure-sensitive heating part composed of a foam made of conductive material. In the pressure-sensitive heating element disclosed in Patent Document 2, the pressure-sensitive heating part generates heat when energized and elastically deforms under compressive load. When energized and under compressive load, the heat generation increases with the increase of the compressive load. Furthermore, the pressure-sensitive heating element disclosed in Patent Document 2 includes a conductive cloth.

[0005] Patent Document 3 discloses a transparent thin-film heater having a transparent heating layer on the surface of a transparent thin-film substrate. In the transparent thin-film heater disclosed in Patent Document 3, the transparent heating layer comprises at least metal nanowires.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2023 / 063377

[0009] Patent Document 2: Japanese Patent Application Publication No. 2019-204674

[0010] Patent Document 3: Japanese Patent Application Publication No. 2010-103041 Summary of the Invention

[0011] The technical problem that the invention aims to solve

[0012] For example, the wiring board in Patent Document 1 uses gold-plated wires. The wiring board disclosed in Patent Document 1 also exhibits high corrosion resistance when used or stored in humid and hot environments.

[0013] However, for example, there are sometimes requirements for wiring boards to be configured with higher design flexibility. Additionally, for example, for wiring boards used as heaters for optical sensors such as LiDAR (Light Detection and Ranging or Laser Imaging Detection and Ranging), there are sometimes requirements for wiring boards that are more suitable for their function. To address these requirements, for example, it is considered to blacken the electrically conductive components used in the wiring board.

[0014] In the pressure-sensitive heating element disclosed in Patent Document 2, a copper-nickel plated fabric with a carbon coating is used as the conductive cloth. When the pressure-sensitive heating element of Patent Document 2 is used or stored in a humid and hot environment, corrosion occurs due to the use of the copper-nickel plated fabric with a carbon coating. Therefore, the pressure-sensitive heating element of Patent Document 2 has low corrosion resistance in humid and hot environments. Patent Document 3's transparent thin-film heater uses silver nanowires. The silver nanowires used in the transparent thin-film heater of Patent Document 3 are described as employing a silver alloy for sulfidation stability. These silver nanowires are not blackened. However, the silver nanowires of Patent Document 3 have difficulties in corrosion stability when used or stored in humid and hot environments.

[0015] For example, in the wiring harness disclosed in Patent Document 1, it is believed that by using a conductive wire as a carbon-coated wire as disclosed in Patent Document 2, a wiring harness with higher design flexibility can be obtained. However, when a wiring board using a carbon-coated wire is constructed, for example, if it is used or stored in a humid and hot environment, the wiring board will corrode, and the resistance value of the wiring board may increase.

[0016] The purpose of this invention is to provide a wiring board that can achieve blackening of conductive linear materials and inhibit corrosion in humid and hot environments.

[0017] Technical solutions for solving technical problems

[0018] [1] A wiring board, comprising: a wiring body having a conductive wire; a pair of electrodes in direct contact with the conductive wire, wherein the infrared reflectivity of the conductive wire at a wavelength of 1000 nm is 0% or more and 90% or less, and the resistance value change rate after standing for 1000 hours in a humid and hot environment of 85°C and 85%RH is 50% or less.

[0019] [2] According to the wiring board described in [1], the relationship between the axial resistance value R of the electrode and the overall axial resistance value r of the conductive wire satisfies the condition expressed by the following mathematical formula (F1).

[0020] r>R···(F1)

[0021] [3] The wiring board according to [1] or [2] further comprises a resin layer that directly or indirectly supports the wiring body.

[0022] [4] The wiring board according to any one of [1] to [3], wherein the maximum width of the electrode is more than 1 mm and less than 10 mm.

[0023] [5] The wiring board according to any one of [1] to [4], wherein the wiring body has a structure in which the conductive wires are spaced apart.

[0024] [6] The wiring board according to any one of [1] to [5], wherein the wiring body is composed of only one of the conductive wires.

[0025] [7] The wiring board according to any one of [1] to [6], wherein the conductive wire is covered with sulfide or palladium.

[0026] [8] The wiring board according to any one of [1] to [7], wherein the conductive wire is covered with silver sulfide.

[0027] According to one aspect of the present invention, a wiring board is provided that, compared with conventional wiring boards, enables the blackening of conductive linear bodies and inhibits corrosion in humid and hot environments. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a wiring board according to an embodiment of the present invention.

[0029] Figure 2 It means Figure 1 A cross-sectional view of section II-II.

[0030] Figure 3 It is a graph showing the relationship between the placement time and the rate of change of resistance value under humid and hot conditions. Detailed Implementation

[0031] [Implementation Method]

[0032] Hereinafter, the present invention will be described with reference to the accompanying drawings, using embodiments as examples. The present invention is not limited to the embodiments described. Furthermore, in the accompanying drawings, some parts are shown in enlarged or reduced form for ease of explanation.

[0033] [Panel Board]

[0034] like Figure 1 and Figure 2As shown, the wiring board 100 of this embodiment includes a wiring body 2 and a pair of electrodes 4. The wiring body 2 has a conductive wire-like body 21. The pair of electrodes 4 are in direct contact with the conductive wire-like body 21. Moreover, the infrared reflectance of the conductive wire-like body 21 at a wavelength of 1000 nm is 0% or more and 90% or less. In addition, the resistance change rate of the wiring board 100 after being left to stand in a humid and hot environment of 85°C and 85% RH for 1000 hours is 50% or less.

[0035] like Figure 1 and Figure 2 As shown, the wiring board 100 also includes a substrate 1 and a resin layer 3. In the wiring board 100, the wiring body 2 has a structure in which conductive wires 21 are arranged. In addition, the resin layer 3 directly or indirectly supports the wiring body 2.

[0036] The wiring board 100 of this embodiment, by having the above-described structure, can achieve blackening of the conductive wires 21 and suppress corrosion in humid and hot environments. The inventors speculate the following reasons for this. By suppressing the infrared reflectivity of the conductive wires 21 used in the wiring board 100 to a lower level than before, the diffuse reflection of light from the conductive wires 21 is suppressed, thus enabling the blackening of the conductive wires 21. For example, blackening can be achieved when using carbon-coated wires as conductive wires. However, when using carbon-coated wires, the humid and hot durability of the wiring board decreases, resulting in a significant change in the resistance value of the wiring board. In the wiring board 100, there is a structure in which the conductive wires 21 are arranged at intervals. When using carbon-coated wires as conductive wires in a wiring board with such a structure, corrosion occurs when used or stored in a humid and hot environment, thereby increasing the rate of change in the resistance value of the wiring board. On the other hand, in the wiring board 100 of this embodiment, the conductive wire 21 is configured such that its infrared reflectance at a wavelength of 1000 nm is in the range of 0% or more and 90% or less. This allows for the blackening of the conductive wire 21. Furthermore, the wiring board 100 of this embodiment is configured such that its resistance value changes by less than 50% after standing in a humid and hot environment of 85°C and 85% RH for 1000 hours. This improves the corrosion resistance of the conductive wire 21 in a humid and hot environment. As a result, the wiring board 100 of this embodiment can achieve the blackening of the conductive wire 21 and suppress corrosion in a humid and hot environment.

[0037] (Substrate)

[0038] The substrate 1 can directly or indirectly support the wiring harness 2. Alternatively, the substrate 1 may not be necessary. The substrate 1 is a component provided as required.

[0039] Examples of materials that can be used as substrate 1 include resin, paper, metal, nonwoven fabric, cloth, and glass. From the viewpoint of strength or operability, resin or glass is preferred as the material for substrate 1. Examples of resins used in substrate 1 include polyethylene, polypropylene, polystyrene, polycarbonate, and polyacetal.

[0040] The substrate 1 may or may not contain a colorant. This colorant allows the transmittance of visible and near-infrared light in the wiring board 100 to be adjusted to a target range. Alternatively, the colorant may be contained within the substrate 1 or in a covering layer (not shown) disposed on the outside of the substrate 1. The covering layer is a layer disposed as needed.

[0041] When the wiring board 100 has a cover layer (not shown) on the outside of the substrate 1, the cover layer is disposed on at least one side of the substrate 1. That is, the cover layer may be disposed on the side of the substrate 1 where the pair of electrodes 4 are disposed, or it may be disposed on the side of the substrate 1 opposite to the side where the pair of electrodes 4 are disposed. The cover layer may be disposed in direct contact with the substrate 1. When the cover layer is disposed on the side of the substrate 1 where the pair of electrodes 4 are disposed, the pair of electrodes 4 may also be disposed in direct contact with the cover layer.

[0042] When the substrate 1 has a coating layer, the visible light transmittance of the coating layer in the wavelength range of 380 nm to 700 nm is preferably 10% or less. More preferably, the visible light transmittance of the coating layer in the wavelength range of 380 nm to 700 nm is 8% or less, and even more preferably 6% or less. The hue of the coating layer is not particularly limited as long as it can adjust the visible light transmittance in the wavelength range of 380 nm to 700 nm to 10% or less. For example, the coating layer is preferably colored black. Black is any hue that is generally recognized as black. When the coating layer is colored black, for example, it can be colored black by an infrared-transmitting ink containing one pigment, by an infrared-transmitting ink containing two or more pigments, or by multiple infrared-transmitting inks exhibiting different colors. Furthermore, regarding the visible light transmittance of the coating layer in the wavelength range of 380 nm to 700 nm, the highest value of the visible light transmittance in this wavelength range is preferably within the range described above.

[0043] From the viewpoint of easy application to light-based sensing and detection techniques, the coating layer preferably has a desired infrared transmittance and a certain or higher refractive index.

[0044] The refractive index of the cladding layer at a wavelength of 905 nm is preferably 1.65 or higher, more preferably 1.75 or higher, and even more preferably 1.85 or higher. By making the refractive index of the cladding layer 1.65 or higher, it is easy to use, for example, as a component for an optical sensor, which is used in a technology that uses light to sense the wiring board 100. There is no particular upper limit to the refractive index of the cladding layer at a wavelength of 905 nm, but it is preferably 3.00 or lower, more preferably 2.70 or lower, and even more preferably 2.40 or lower.

[0045] The coating layer preferably contains infrared-transmitting ink. The coating layer preferably has a near-infrared transmittance of 70% or more in the wavelength range of 905 nm to 1000 nm. The infrared-transmitting ink is an ink that transmits near-infrared light in the wavelength range of 905 nm to 1000 nm while suppressing the transmission of visible light and ultraviolet light. The infrared-transmitting ink can transmit, for example, 70% or more of near-infrared light in the wavelength range of 905 nm to 1000 nm. More preferably, the near-infrared transmittance in the coating layer containing the infrared-transmitting ink in the wavelength range of 905 nm to 1000 nm is 75% or more, further preferably 80% or more, and even more preferably 85% or more. The near-infrared transmittance in the coating layer containing the infrared-transmitting ink in the wavelength range of 905 nm to 1000 nm can be less than 100%, can be 99% or less, or can be 95% or less. If the coating layer contains infrared-transmitting ink, and the transmittance of near-infrared light in the 905nm to 1000nm wavelength range of the coating layer is 70% or more, then the wiring board 100 can be easily used as a component for an optical sensor, for example. Furthermore, regarding the transmittance of near-infrared light in the 905nm to 1000nm wavelength range of the coating layer, the lowest value of the near-infrared transmittance in this wavelength range is preferably within the range described above.

[0046] Infrared transmission inks may contain pigments and resin components. Preferably, infrared transmission inks contain additives as needed. Pigments may contain at least one of dyes and coloring pigments. Coloring pigments are preferred as pigments. Coloring pigments are not particularly limited; examples include inorganic and organic pigments, which can be used alone or in combination. Inorganic pigments are not particularly limited; examples include bismuth sulfide, carbon black, iron oxide red, cadmium red, Prussian blue, and ultramarine, which can be used alone or in combination of two or more. Organic pigments are not particularly limited; examples include lactam black pigments, perylene pigments, phthalocyanine pigments, benzofuranone pigments, azo pigments, anthraquinone pigments, indanthrene pigments, isoindolinetone pigments, quinacridone pigments, quinophthalone pigments, diketopyrrolopyrrole pigments, dioxazine pigments, and thioindigo pigments, which can be used alone or in combination of two or more. The coloring pigment can be an organic pigment. From the viewpoint that the image of the object obtained by irradiating the object with a laser is easier to sharpen, it is preferable to include at least one of the group consisting of perylene pigments and phthalocyanine pigments, which can set a low refractive index and suppress light scattering. Furthermore, by including at least one of the group consisting of perylene pigments and phthalocyanine pigments in the infrared transmitting ink, infrared transmittance can be easily obtained while suppressing the visible light transmittance of the coating layer.

[0047] Perylene-based pigments are not particularly limited to any organic pigment with a perylene skeleton. For example, perylene-based pigments have a structure that removes two oxygen atoms from the six-membered ring constituting perylenetetracarboxylic dianhydride. Specifically, examples of perylene-based pigments include perylene red, perylene violet, and perylene black. Perylene-based pigments can be used alone or in combination of two or more.

[0048] Phthalocyanine pigments are not particularly limited to any organic pigment having a phthalocyanine skeleton. Phthalocyanine pigments, for example, have a cyclic structure formed by four phthalimides cross-linked by nitrogen atoms. Phthalocyanine pigments may contain a coordinating metal. Examples of coordinating metals include copper, magnesium, titanium, iron, cobalt, nickel, zinc, and aluminum. When a phthalocyanine pigment contains a coordinating metal, it can be a copper phthalocyanine pigment. Specifically, examples of phthalocyanine pigments include phthalocyanine blue and phthalocyanine green. Phthalocyanine pigments can be used alone or in combination of two or more.

[0049] The resin component is not particularly limited, and various resins such as acrylic resins, vinyl chloride resins, butyral resins, polyester resins, polyurethane resins, cellulose resins, and epoxy resins can be used. One or more of these resins can be used in combination. Preferably, the resin component includes an acrylic resin. An acrylic resin is also more preferred.

[0050] Infrared transmission inks can use at least one additive from the following sources as needed: surfactants, surface conditioners, defoamers, leveling agents, curing accelerators, dispersants, light stabilizers, flow conditioners, polymerization inhibitors, and oxidative polymerization inhibitors.

[0051] There is no particular limitation on the thickness of the coating layer. The thickness of the coating layer is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 4 μm or more. The thickness of the coating layer is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 15 μm or less.

[0052] The thickness of the substrate 1 is preferably 0.05 mm or more, more preferably 0.25 mm or more, even more preferably 0.5 mm or more, even more preferably 1.0 mm or more, and particularly preferably 1.5 mm or more. The thickness of the substrate 1 is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less. By keeping the thickness of the substrate 1 within the range of 0.05 mm or more and 10 mm or less, excellent strength and the like can be obtained.

[0053] (Wiring)

[0054] The wiring harness 2 includes conductive wires 21. In the wiring board 100, the wiring harness 2 has a structure in which conductive wires 21 are arranged. Alternatively, in the wiring board 100, the wiring harness 2 has a structure in which multiple conductive wires 21 are arranged in parallel. In the wiring board 100, the wiring harness 2 has a structure in which multiple conductive wires 21 are arranged with intervals between each other; however, the wiring board 100 of this embodiment is a preferred example and is not limited to this. The wiring harness 2 may also not have a structure in which multiple conductive wires 21 are arranged with intervals between each other. The wiring harness 2 may also be composed of only one conductive wire 21. When the wiring harness 2 is composed of only one conductive wire 21, the wiring harness 2 may also be formed with a pattern in which one conductive wire 21 has at least one bend.

[0055] In the wiring board 100, the conductive wire 21 appears as a straight line when viewed from above. However, it is not limited to this; the conductive wire 21 can also form a wave shape when viewed from above. Examples of wave shapes include sine waves, rectangular waves, triangular waves, and sawtooth waves. For instance, if the wiring board 2 has such a wave shape, then when the wiring board 100 is extended along the axial direction of the conductive wire 21, breakage of the conductive wire 21 can be suppressed.

[0056] The volume resistivity of the conductive linear body 21 is preferably 1.0 × 10⁻⁶. -9 Ω·m or more, more preferably 3.0 × 10 -9 Ω·m or higher, more preferably 1.0 × 10⁻⁶ -8Ω·m or higher. Furthermore, the volume resistivity of the conductive linear body 21 is preferably 1.0 × 10⁻⁶. -3 Below Ω·m, more preferably 1.0×10 -4 Below Ω·m, more preferably 5.0 × 10⁻⁶ -5 Below Ω·m. If the volume resistivity of the conductive linear body 21 is made to be within the above range, the surface resistivity of the wiring body 2 can be easily reduced.

[0057] The volume resistivity of the conductive wire 21 was measured as follows. Silver paste was applied to the end of the conductive wire 21 and a 40mm section from the end, and the resistance of the end and the 40mm section from the end was measured. Then, the cross-sectional area of ​​the conductive wire 21 (unit: m²) was measured. 2 Multiply the resistance value by the above value, divide the resulting value by the measured length (0.04m) to calculate the volume resistivity of the conductive linear body 21.

[0058] The cross-sectional shape of the conductive linear body 21 is not particularly limited and can be polygonal, flat, elliptical, or circular. From the viewpoint of integration with the resin layer 3, the cross-sectional shape of the conductive linear body 21 is preferably elliptical or circular.

[0059] When the cross-section of the conductive wire 21 is circular, the diameter D of the conductive wire 21 (refer to...) Figure 2 The diameter D of the conductive wire 21 is preferably 3 μm or more and 200 μm or less. From the viewpoint of suppressing the rise of the thin-layer resistance and improving the heating efficiency and insulation failure resistance of the wiring board 100, the diameter D of the conductive wire 21 is more preferably 4 μm or more, and even more preferably 5 μm or more. The diameter D of the conductive wire 21 is more preferably 150 μm or less, even more preferably 100 μm or less, even more preferably 50 μm or less, and even more preferably 20 μm or less.

[0060] When the cross-section of the conductive linear body 21 is elliptical, it is preferable that the major axis is within the same range as the diameter D mentioned above.

[0061] The diameter D of the conductive linear body 21 is obtained by observing the conductive linear body 21 with a digital microscope, measuring the diameter of the conductive linear body 21 at 5 randomly selected locations, and taking the average value.

[0062] When the wiring harness 2 has a structure in which multiple conductive wires 21 are arranged at intervals, the interval L of the conductive wires 21 (refer to...) Figure 2The spacing L 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 linear bodies 21 is preferably 50 mm or less, more preferably 30 mm or less, even more preferably 20 mm or less, and particularly preferably 5 mm or less.

[0063] If the spacing between the conductive wires 21 is within the range described above, the conductive wires 21 exist in a certain degree of density, thereby improving the function of the wiring board 100 in maintaining a low resistance of the wiring body 2.

[0064] Regarding the spacing L of the conductive wires 21, the spacing between two adjacent conductive wires 21 is determined by observing the conductive wires 21 of the wiring harness 2 using a digital microscope, for example.

[0065] Furthermore, the interval between two adjacent conductive wires 21 refers to the length along the direction in which the conductive wires 21 are arranged, and is the length between the opposite portions of the two conductive wires 21 (see reference). Figure 2 When the conductive linear bodies 21 are arranged at unequal intervals, the interval L is the average value of the intervals between all adjacent conductive linear bodies 21.

[0066] The shape of the conductive wire 21 is not particularly limited as long as it meets both of the following conditions (a) and (b). Condition (a) The infrared reflectance of the conductive wire 21 at a wavelength of 1000 nm is 0% or more and 90% or less. Condition (b) The resistance change rate of the wiring board 100 after standing in a humid and hot environment of 85°C and 85%RH for 1000 hours is 50% or less.

[0067] The conductive wire 21 can be manufactured by methods such as etching, screen printing, or inkjet printing. The conductive wire 21 can be a wire containing metal wires (hereinafter also referred to as a "metal wire body"). Metal wires have high thermal conductivity, high electrical conductivity, and high operability. The metal wire body can significantly reduce resistance, and even with a very small diameter, it can conduct current required for the heating of the wiring board 100. Therefore, the conductive wire 21 can be made difficult to see. That is, if a metal wire body is used as the conductive wire 21, it is easy to reduce the resistance of the wiring board 2 while increasing light transmittance. Furthermore, the wiring board 100 can easily achieve rapid heating. In addition, as described above, it is easy to obtain wires with small diameters.

[0068] A metal wire can be a single metal wire or a wire made by twisting together multiple metal wires.

[0069] Examples of metal wires include those containing metals such as copper, aluminum, tungsten, iron, molybdenum, nickel, titanium, silver, and gold; or steels such as stainless steel and carbon steel; brass; phosphor bronze; zirconium copper alloy; beryllium copper; iron-nickel; nickel-chromium alloy; nickel-titanium; cantaloupes; Hastelloy; and rhenium-tungsten alloys. From the viewpoint of low volume resistivity, wires containing one or more metals selected from tungsten and molybdenum, as well as alloys containing them, are particularly preferred.

[0070] From the viewpoint of achieving blackening of the conductive linear body 21 and suppressing corrosion of the wiring board 100 in a humid and hot environment, the conductive linear body 21 is preferably a linear body coated with sulfide or palladium. In this specification, coating with sulfide is sometimes referred to as sulfide coating, and coating with palladium is sometimes referred to as palladium coating. The linear body coated with sulfide or palladium can be (i) a linear body directly coated with sulfide or palladium, (ii) a linear body coated with sulfide or palladium through a coating of a material other than sulfide or a material other than palladium, or (iii) a coating in the presence of a mixture of sulfide and a material other than sulfide or a mixture of palladium and a material other than palladium. Examples of materials other than palladium include metals other than palladium and metal oxides. For example, when the palladium-coated wire is a metallic wire, palladium can be directly coated onto the metallic wire, or it can be coated onto the metallic wire through a coating of a metal other than palladium or a metal oxide, or it can be coated onto the metallic wire in a state where a metal other than palladium or a metal oxide is mixed with palladium. From the viewpoint of further achieving blackening of the conductive wire 21 and further suppressing corrosion of the wiring board 100 in a humid and hot environment, the conductive wire 21 is preferably a wire coated with silver sulfide. The conductive wire 21 is also preferably a wire coated with a metal other than palladium or a metal oxide mixed with palladium. If the conductive wire 21 is a wire coated with sulfide or a wire coated with palladium, the metallic luster is reduced, and the presence of the metallic wire is easily not obvious. In addition, when the metallic wire is coated with sulfide or palladium, metal corrosion is also easily suppressed, so conditions (a) and (b) above are easily satisfied. When the conductive linear body 21 is coated with a sulfide or a palladium, the sulfide or palladium coating on the linear body can be formed, for example, by the plating and vapor deposition methods described above. The conductive linear body 21 can be, for example, a linear body coated with a sulfide or a linear body coated with a palladium. Preferably, the conductive linear body 21 is a linear body coated with silver sulfide. The conductive linear body 21 is also preferably a linear body coated with a metal other than palladium or a metal oxide mixed with palladium. The metal or metal oxide mixed with palladium is not particularly limited; for example, one or more selected from the group consisting of copper, silver, and oxides of these metals can be cited.

[0071] The conductive linear body 21 has an infrared reflectance of 0% or more and 90% or less at a wavelength of 1000 nm. From the viewpoint of blackening the conductive linear body 21, the infrared reflectance at a wavelength of 1000 nm is preferably 86% or less, more preferably 78% or less, more preferably 74% or less, even more preferably 50% or less, even more preferably 35% or less, and even more preferably 30% or less. From the same viewpoint, the infrared reflectance of the conductive linear body 21 at a wavelength of 1000 nm can be 1% or more, 3% or more, 6% or more, 8% or more, or 10% or more.

[0072] The infrared reflectance of the conductive linear body 21 at a wavelength of 1000 nm can be measured by the method described in the embodiments below.

[0073] (Resin layer)

[0074] The resin layer 3 directly or indirectly supports the wiring harness 2. Alternatively, the resin layer 3 may not be necessary. The resin layer 3 is a component provided as needed. Through this resin layer 3, the resistance value of the wiring harness 2 can be stabilized. That is, through this resin layer 3, the conductive wire 21 can be fixed, and the contact between the conductive wire 21 and the electrode 4 can be stabilized, making it less likely for the resistance value to rise.

[0075] The thickness of the resin layer 3 is not particularly limited. The thickness of the resin layer 3 can be greater than or equal to the diameter D of the conductive wire 21, or it can be less than the diameter D of the conductive wire 21. If the thickness of the resin layer 3 is greater than or equal to the diameter D of the conductive wire 21, the wiring element 2 can be included in the resin layer 3. When the thickness of the resin layer 3 is less than the diameter D of the conductive wire 21, the wiring element 2 is exposed from the resin layer 3. Furthermore, when the wiring element 2 is exposed from the resin layer 3, it can be exposed on the side of the substrate 1 or on the opposite side of the substrate 1. The thickness of the resin layer 3 is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. The thickness of the resin layer 3 is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less.

[0076] From the viewpoint of further improving the energy storage modulus, the resin layer 3 is preferably a layer formed by the cured product of a curable adhesive.

[0077] Examples of curable adhesives include thermosetting adhesives that cure by heat and adhesives that cure by energy rays. Examples of energy rays include ultraviolet rays, visible energy rays, infrared rays, and electron beams. It should be noted that "energy ray curing" also includes thermal curing performed by heating using energy rays.

[0078] Thermosetting adhesives preferably contain thermosetting resins. There are no particular limitations on the thermosetting resins, but 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. They can be used alone or in combination of two or more. From the viewpoint of suitability for curing with imidazole-based curing catalysts, epoxy resins, phenolic resins, melamine resins, urea resins, amine compounds, and acid anhydride compounds are preferred as thermosetting resins. In particular, from the viewpoint of exhibiting excellent curability, epoxy resins, phenolic resins, mixtures thereof, or mixtures of epoxy resins with at least one selected from phenolic resins, melamine resins, urea resins, amine compounds, and acid anhydride compounds are preferred, with epoxy resins being the most preferred.

[0079] From the viewpoint of improving the storage modulus of resin layer 3, aromatic epoxy resins or cyclic epoxy resins such as alicyclic epoxy resins are preferred as epoxy resins. Epoxy resins with flexible chain segments such as oxyalkylene chains tend to reduce the storage modulus of resin layer 3.

[0080] The energy-curable adhesive preferably comprises an energy-curable resin. Examples of energy-curable resins include compounds having at least one polymerizable double bond within the molecule, and acrylate compounds having (meth)acryloyl groups are preferred.

[0081] 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-butanediol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate, which contain a chain-like aliphatic backbone; dicyclopentyl di(meth)acrylate and other cyclic aliphatic backbones; polyethylene glycol di(meth)acrylate and other polyalkylene glycol (meth)acrylates; low polyester (meth)acrylates, urethane (meth)acrylate oligomers, epoxy-modified (meth)acrylates, polyether (meth)acrylates other than polyalkylene glycol (meth)acrylates, and itaconic acid oligomers, etc.

[0082] The weight-average molecular weight (Mw) of the energy-curable resin is preferably 100 or more, more preferably 300 or more. Furthermore, this weight-average molecular weight is preferably 30,000 or less, more preferably 10,000 or less. It should be noted that the weight-average molecular weight in this specification is a value converted from standard polystyrene determined by gel permeation chromatography (GPC).

[0083] The adhesive may contain only one type of energy-curing resin or two or more types. When there are two or more energy-curing resins, their combination and ratio can be chosen arbitrarily.

[0084] When using energy-curable resins or thermosetting resins, photopolymerization initiators and thermal polymerization initiators are preferred. By using photopolymerization initiators and thermal polymerization initiators, the polymerization reaction of the curable resin can be easily initiated, and the control of the curing reaction becomes easier.

[0085] Examples of photopolymerization initiators include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexylphenyl 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, among others.

[0086] In addition to photoradical polymerization initiators, photocationic polymerization initiators can also be cited as photopolymerization initiators. Photocationic polymerization initiators are compounds that generate cationic species by irradiation with energy rays, initiating a curing reaction of cationic curable compounds. They consist of a cationic portion that absorbs energy rays and an anionic portion that becomes the source of acid generation.

[0087] 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 bromide salt compounds. From the viewpoint of excellent compatibility and excellent storage stability of the resulting adhesive, sulfonium salt compounds are preferred as photocationic polymerization initiators, and aromatic sulfonium salt compounds having aromatic groups are more preferred.

[0088] Examples of sulfonium salt compounds include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, and triphenylsulfonium tetra(pentafluorophenyl)borate.

[0089] Examples of iodonium salt compounds include diphenyliodonium tetra(pentafluorophenyl)borate, diphenyliodonium hexafluorophosphate, and (tricumyl)iodonium tetra(pentafluorophenyl)borate.

[0090] Examples of phosphonium salt compounds include tri-n-butyl(2,5-dihydroxyphenyl)phosphonium bromide and hexadecyltributylphosphonium chloride.

[0091] Examples of ammonium salt compounds include benzyltrimethylammonium chloride, phenyltributylammonium chloride, and benzyltrimethylammonium bromide.

[0092] Examples of antimonate compounds include triphenylsulfonium hexafluoroantimonate, p-(phenylthio)phenyldiphenylsulfonium hexafluoroantimonate, and diallyl iodonium hexafluoroantimonate.

[0093] Examples of thermal polymerization initiators include persulfates such as hydrogen peroxide, ammonium persulfate, sodium persulfate, and potassium persulfate; azo compounds such as 2,2'-azobis(2-amidinylpropane) dihydrochloride, 4,4'-azobis(4-cyanopentanoic acid), 2,2'-azobisisobutyronitrile, and 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile); and organic peroxides such as benzoyl peroxide, lauroyl peroxide, peracetic acid, persuccinic acid, di-tert-butyl peroxide, tert-butyl hydrogen peroxide, and cumene hydroperoxide, which are thermal free radical polymerization initiators.

[0094] In addition to the aforementioned thermal free radical polymerization initiators, thermal cationic polymerization initiators can also be cited as thermal polymerization initiators. Thermal cationic polymerization initiators are compounds capable of generating cationic 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 viewpoints of ease of acquisition and the ability to produce resin layers 3 with superior adhesion and transparency.

[0095] Examples of sulfonium salts include triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, benzyl(4-hydroxyphenyl)methylsulfonium tetra(pentafluorophenyl)borate, (4-hydroxyphenyl)methyl(4-methylbenzyl)sulfonium tetra(pentafluorophenyl)borate, and triphenylsulfonium hexafluoroarsenate.

[0096] Examples of quaternary ammonium salts include tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, and tetrabutylammonium hydrosulfate. Examples of phosphonium salts include ethyltriphenylphosphonium hexafluoroantimonate and tetrabutylphosphonium hexafluoroantimonate.

[0097] Examples of diazonium salts include chlorobenzene diazonium salts. Examples of iodonium salts include diphenyliodonium hexafluoroarsenate, bis(4-chlorophenyl)iodonium hexafluoroarsenate, bis(4-bromophenyl)iodonium hexafluoroarsenate, and phenyl(4-methoxyphenyl)iodonium hexafluoroarsenate.

[0098] These polymerization initiators can be used alone or in combination of two or more.

[0099] When using these polymerization initiators to form a crosslinked structure, the amount used is preferably 0.1 parts by mass or more and 30 parts by mass or less relative to 100 parts by mass of energy-curable resin or thermosetting resin, 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.

[0100] In addition, when using thermosetting resins, curing catalysts such as imidazole-based curing catalysts can also be used.

[0101] In this embodiment, in order to easily maintain the sheet shape before curing, the curable adhesive may contain a softening agent together with the energy-curable resin or thermosetting resin. Examples of polymers used as softening agents include phenoxy resins, polyolefin resins or modified versions thereof, polyamide-imide resins, polyimide resins, rubber-based resins, and acrylic resins.

[0102] These softening ingredients can be used alone or in combination of two or more.

[0103] In this embodiment, when the curable adhesive contains a flexibility-modifying component, from the viewpoint of adjusting the storage modulus of the resin layer 3, the total amount of the energy-curable resin or thermosetting resin contained in the adhesive is preferably 15 parts by mass or more and 300 parts by mass or less relative to 100 parts by mass of the flexibility-modifying component, 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. Furthermore, when the adhesive contains an energy-curable resin or thermosetting resin but does not contain a flexibility-modifying component, there is a tendency for the storage modulus of the resin layer 3 to become excessively high.

[0104] In this embodiment, the curable adhesive may or may not contain filler material. From the viewpoint of further improving the storage modulus of the resin layer 3 at 23°C, the curable adhesive may contain filler material. From the viewpoint of suppressing the increase in the storage modulus of the resin layer 3 at 23°C, the curable adhesive may not contain filler material.

[0105] Examples of filler materials include inorganic powders such as silica, alumina, talc, calcium carbonate, titanium dioxide, iron oxide red, silicon carbide, and boron nitride; and beads, single-crystal fibers, and glass fibers formed by spherizing inorganic powders. Among these, silica fillers and alumina fillers are preferred. One type of filler material can be used alone, or two or more can be used in combination.

[0106] Curing adhesives may also contain other components. Examples of such other components include known additives such as organic solvents, coupling agents, flame retardants, tackifiers, UV absorbers, antioxidants, preservatives, fungicides, plasticizers, defoamers, and wetting modifiers.

[0107] (electrode)

[0108] Electrode 4 is used to supply current to the conductive wire 21. There is a pair of electrodes 4. Electrode 4 is in direct contact with the conductive wire 21. Moreover, electrode 4 is configured to be electrically connected to both ends of the conductive wire 21.

[0109] The relationship between the axial resistance R of electrode 4 and the overall axial resistance r of conductive linear body 21 preferably satisfies the condition shown in the following mathematical formula (F1). When the condition expressed by the following mathematical formula (F1) is satisfied, the heat generation of electrode 4 can be reduced.

[0110] r>R···(F1)

[0111] The value of R / r is preferably 0.0001 or higher, more preferably 0.0005 or higher. Furthermore, R / r is preferably 0.3 or lower, more preferably 0.15 or lower. When the wiring board 100 is used as a heating element, the wiring body 2 needs to have a certain degree of resistance in order to heat up the wiring body 2; on the other hand, it is preferable that the electrode 4 can flow current as easily as possible.

[0112] The axial resistance R of electrode 4 and the overall axial resistance r of conductive wire 21 can be measured using a tester. First, the axial resistance R of electrode 4 and the axial resistance (for each) of conductive wire 21 are measured. The axial resistance of conductive wire 21 is inversely proportional to the cross-sectional area of ​​conductive wire 21, therefore, the overall axial resistance r of conductive wire 21 is calculated by dividing the axial resistance (for each wire) of conductive wire 21 by the number of conductive wires 21.

[0113] The Young's modulus of electrode 4 is preferably greater than 1×10⁻⁶. 9 Pa and is 1×10 11 Below Pa. If the Young's modulus of electrode 4 is 1×10⁻⁶. 11Below Pa, there is a tendency to further reduce the contact resistance between the conductive wire 21 and the electrode 4. From the same point of view, the Young's modulus of the electrode 4 is more preferably 8.5 × 10⁻⁶. 10 Pa or less, more preferably 7×10 Pa 10 Below Pa. The Young's modulus of electrode 4 can be 2 × 10⁻⁶. 9 Above Pa, it can be 3×10 9 Pa or above, or 5 × 10 9 Pa or above.

[0114] The Young's modulus of electrode 4 can be determined by a continuous rigidity measurement method. For example, the Young's modulus of electrode 4 disposed on a glass substrate at 25°C can be determined using a nanoindenter (manufactured by MTS Systems) under the following conditions.

[0115] Indenter shape: triangular pyramid

[0116] Maximum indentation depth of the indenter: 500nm

[0117] Vibration frequency: 75Hz

[0118] The maximum thickness of electrode 4 is preferably 40 μm or less. More preferably, the maximum thickness of electrode 4 is 30 μm or less, and even more preferably, 20 μm or less. If the maximum thickness of electrode 4 is 40 μm or less, the deformation of conductive wire 21 is small when it comes into contact with electrode 4, and it tends to easily stabilize conductivity. The maximum thickness of electrode 4 is preferably 5 μm or more, more preferably 8 μm or more, and even more preferably 10 μm or more.

[0119] When viewing the wiring board 100 from above, the maximum width of the electrode 4 is preferably 1 mm or more and 10 mm or less. The maximum width of the electrode 4 is preferably within the aforementioned range. More preferably, the maximum width of the electrode 4 is 1.5 mm or more, and even more preferably 2 mm or more. More preferably, the maximum width of the electrode 4 is 8 mm or less, even more preferably 6 mm or less, and even more preferably 4 mm or less. When viewing the wiring board 100 from above, if the maximum width of the electrode 4 is 1 mm or more and 10 mm or less, it is easy to ensure contact with the conductive wire 21.

[0120] Electrode 4 can be formed using known electrode materials. Examples of electrode materials include conductive pastes, metal foils, and metal wires.

[0121] Examples of conductive pastes include silver paste, copper paste, and carbon paste. Among these, from the viewpoint of low volume resistivity, silver paste is preferred.

[0122] When the electrode material is a metal foil or metal wire, the metal used as the foil or wire can include metals such as copper, aluminum, tungsten, iron, molybdenum, nickel, titanium, silver, and gold; or alloys of two or more metals such as stainless steel, carbon steel, brass, phosphor bronze, zirconium copper alloy, beryllium copper, iron-nickel, nickel-chromium alloy, nickel-titanium, cantaloupes, Hastelloy, and rhenium-tungsten. Additionally, the metal foil or wire can also be plated with gold, tin, zinc, silver, nickel, chromium, nickel-chromium alloys, or solder. When the electrode material is a metal wire, there can be one or more wires.

[0123] Electrode 4 is preferably gold-plated. This gold plating process can suppress the migration of electrode 4.

[0124] (Uses of patch panels, etc.)

[0125] The wiring board 100 of this embodiment can be suitable for use as a surface heater, for example. In this case, its application as a surface heater can include, for example, a defroster or frost remover for window glass. In addition to being used as a surface heater, it can also be used as a flat cable for wiring electrical signals. Furthermore, the wiring board 100 of this embodiment can also be used as a heater for optical sensors. In this case, it can be used as a heater for optical sensors such as LiDAR sensors.

[0126] The resistance change rate of the wiring board 100 when used or stored in a humid and hot environment at 85°C and 85% RH is preferably 20% or less, more preferably 18% or less, even more preferably 17% or less, even more preferably 15% or less, and even more preferably 13% or less. The resistance change rate of the wiring board 100 when used or stored in a humid and hot environment at 85°C and 85% RH is preferably 0% or close to 0%. The resistance change rate of the wiring board 100 when used or stored in a humid and hot environment can be 0% or more, or 0.1% or more. If the resistance change rate is 20% or less, corrosion of the wiring board can be suppressed even when used or stored in a humid and hot environment. Furthermore, the wiring board can be used or stored in a humid and hot environment. The resistance change rate can be measured by the method described in the embodiments described later. Here, the time for using or storing the wiring board 100 in the aforementioned humid and hot environment is 1000 hours. Furthermore, the aforementioned resistance change rate can also be less than 0%. Furthermore, the aforementioned rate of change in resistance value, measured in absolute terms as the rate of change in resistance value before and after using or storing the wiring board 100 in a humid and hot environment at a temperature of 85°C and a relative humidity of 85%RH, is preferably 0% or more and 20% or less.

[0127] [Manufacturing method of patch panel]

[0128] Next, the manufacturing method of the wiring board 100 according to this embodiment will be described. The manufacturing method of the wiring board 100 according to this embodiment is not particularly limited. The manufacturing method of the wiring board 100 according to this embodiment is an example of a method capable of producing the above-described wiring board 100. The wiring board 100 can be manufactured, for example, through the following steps.

[0129] First, a process is performed to manufacture a wiring sheet having wiring elements 2. In this process, a resin layer 3 is formed on a release liner. If the resin layer 3 is formed of a thermosetting adhesive, a thermosetting adhesive for forming the resin layer 3 is applied to form a coating film. Next, the coating film is dried to form an adhesive layer as the resin layer 3. Then, conductive wires 21 are arranged on the adhesive layer to form the wiring element 2. For example, with an adhesive layer with release liner on the outer peripheral surface of the drum component, the conductive wires 21 are spirally wound onto the adhesive layer while the drum component is rotated. Then, the bundle of spirally wound conductive wires 21 is cut along the axial direction of the drum component. Thus, the wiring element 2 is formed and disposed on the adhesive layer. In this way, a wiring sheet with wiring elements 2 formed on an adhesive layer with release liner is obtained. According to this method, for example, while rotating the drum component, the discharge portion of the conductive wire 21 is moved in a direction parallel to the axis of the drum component, thereby easily adjusting the spacing L of adjacent conductive wires 21 in the wiring harness 2.

[0130] Next, a process is performed to set a pair of electrodes 4 on the substrate 1. In this process, a pair of electrodes 4 can be set by printing, for example, a conductive paste on the substrate 1 in a predetermined configuration and then drying it.

[0131] Next, the fabricated wiring sheet is disposed on the substrate 1 on which a pair of electrodes 4 are provided, and a process is performed to cure the thermosetting adhesive. In this process, the wiring sheet is attached to the substrate 1 on which the pair of electrodes 4 are provided, such that the two ends of the conductive wires 21 in the wiring body 2 of the wiring sheet are in contact with the pair of electrodes 4. Then, after the release tab is peeled off, the thermosetting adhesive is subjected to a prescribed heat treatment to form a resin layer 3, thereby fabricating the wiring board 100.

[0132] [Effects of the Implementation Method]

[0133] According to this embodiment, the following effects can be achieved.

[0134] (1) According to this embodiment, even when used or stored in a humid and hot environment (e.g., at a temperature of 85°C and a relative humidity of 85%RH), the resistance value of the wiring board 100 can be suppressed.

[0135] (2) According to this embodiment, by setting the infrared reflectance of the conductive linear body 21 at a wavelength of 1000 nm to a range of 0% or more and 90% or less, the conductive linear body 21 can be blackened. Therefore, for example, the wiring board 100 can be designed. In addition, for example, the wiring board 100 can be used as a heater for an optical sensor.

[0136] (3) According to this embodiment, the conductive wire 21 can be fixed by the resin layer 3, the deformation in the thickness direction inside the wiring board 100 can be suppressed, the contact between the conductive wire 21 and the electrode 4 can be stabilized, and the resistance value of the wiring body 2 can be stabilized.

[0137] [Variations on the implementation method]

[0138] This invention is not limited to the aforementioned embodiments; variations or improvements within the scope of achieving the objectives of this invention are included in this invention.

[0139] For example, in the above embodiment, the wiring board 100 includes a substrate 1, but is not limited thereto. For example, the wiring board 100 may not include a substrate 1. In this case, the wiring board 100 can be adhered to the substrate using the resin layer 3.

[0140] Furthermore, in the above embodiment, a resin layer 3 is disposed on the surface of the wiring board 100, but it is not limited to this. For example, a protective sheet (not shown) may be disposed on the resin layer 3 of the wiring board 100 to protect the wiring body 2.

[0141] Example

[0142] The present invention will now be described in more detail with reference to specific examples. The present invention is not limited to these examples. Furthermore, unless otherwise specified, proportions expressed in parts by mass refer to the proportions of solid components.

[0143] In addition, the evaluation of the wiring boards obtained in the embodiments is carried out as follows.

[0144] [Reflectivity Evaluation]

[0145] A plating or coating was formed on a tungsten plate with the same composition as the wires used in the embodiments and comparative examples using any of the following materials: a silver sulfide plating, a palladium plating, a copper oxide-palladium plating, or a gold plating, or a carbon coating with the same composition as the coating used in the embodiments and comparative examples 2. The plating or coating was applied using the same method as the coated tungsten wires or carbon-coated tungsten wires used in the embodiments and comparative examples. For tungsten plates with plating formed by silver sulfide plating, palladium plating, copper oxide-palladium plating, gold plating, or carbon coating, the infrared reflectance at a wavelength of 1000 nm was measured using a UV-VIS-NIRSPECTROPHOTOMETER UV-3600 (manufactured by Shimadzu Corporation).

[0146] [Resistance Value Evaluation]

[0147] A ohmmeter (manufactured by Hioki Electric Co., Ltd., product name "RM 3545") was connected to the electrodes to measure the resistance (R1) of the wiring board. After the wiring board was left to stand in a humid and hot environment at 85°C and 85% RH for 1000 hours, the ohmmeter was connected to the electrodes again to measure the resistance (R2). Then, the rate of change of resistance values ​​between R1 and R2 (in %) was calculated using the following mathematical formula (F2). The smaller this rate of change of resistance value, the more the change in the resistance value of the wiring board is suppressed.

[0148] Rate of change of resistance = [(R2-R1) / R1]×100 (%)··· (F2)

[0149] [Appearance Evaluation]

[0150] The wiring boards obtained in each embodiment and comparative example were placed on a black board and visually inspected. In Table 1, cases where conductive wires are not visible but the design is excellent are marked as "A", and cases where conductive wires are visible but the design is poor are marked as "F".

[0151] [Preparation Example 1]

[0152] (Adjustment of curing adhesive)

[0153] A curable adhesive is obtained by combining 100 parts by weight of phenoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "YX7200B35"), 170 parts by weight of polyfunctional hydrogenated bisphenol A diglycidyl ether epoxy compound (manufactured by Mitsubishi Chemical Corporation, product name "YX8000"), 0.2 parts by weight of 8-epoxypropoxyoctyltrimethoxysilane as a silane coupling agent, 2 parts by weight of benzyl(4-hydroxyphenyl)methylsulfonium tetra(pentafluorophenyl)borate as a thermo-cationic polymerization initiator, and 2 parts by weight of (4-hydroxyphenyl)methyl(4-methylbenzyl)sulfonium tetra(pentafluorophenyl)borate.

[0154] [Preparation Example 2]

[0155] (Preparation of (meth)acrylate polymer (A))

[0156] (Meth)acrylate polymer (A) was prepared by solution polymerization of 55 parts by weight of 2-ethylhexyl acrylate, 5 parts by weight of 4-acryloylmorpholine, 15 parts by weight of isobornyl acrylate, and 25 parts by weight of 2-hydroxyethyl acrylate. The molecular weight of the (meth)acrylate polymer (A) was determined by the described method, and the weight-average molecular weight (Mw) was 600,000. Furthermore, based on the glass transition temperature (Tg) of the homopolymers constituting the (meth)acrylate polymer (A), the glass transition temperature (Tg; °C) of the (meth)acrylate polymer (A) was calculated using the FOX formula, and the result was -36.5 °C.

[0157] [Preparation Example 3]

[0158] (Preparation of adhesive composition)

[0159] 100 parts by weight of (meth)acrylate polymer (A) obtained in the above process, 0.18 parts by weight of trimethylolpropane-modified toluene diisocyanate as crosslinking agent (B), 7 parts by weight of ε-caprolactone-modified tri-(2-acryloyloxyethyl)isocyanurate as active energy ray curing component (C), 0.7 parts by weight of a mixture of benzophenone and 1-hydroxycyclohexylphenyl ketone in a 1:1 mass ratio as photopolymerization initiator (D), and 0.28 parts by weight of 3-epoxypropoxypropyltrimethoxysilane as silane coupling agent are mixed and stirred thoroughly, and then diluted with methyl ethyl ketone to obtain a coating solution of adhesive composition.

[0160] [Example 1]

[0161] (Fabrication of silver sulfide-plated tungsten wire)

[0162] A sulfidation solution was prepared by adding 3.5 g of potassium sulfide to 1 L of water. Silver-plated tungsten wire (12 μm in diameter, volume resistivity 5.5 × 10⁻⁶) was then impregnated in the sulfidation solution.-8 A silver sulfide-plated tungsten wire was fabricated using a method involving Ω·m. It should be noted that the thickness of the silver sulfide plating in the fabricated silver sulfide-plated tungsten wire is 0.1 μm. The silver sulfide-plated tungsten wire has a near-black hue.

[0163] (Fabrication of wiring harness)

[0164] On a 38 μm thick release sheet (manufactured by Lintec Corporation, product name "SP-PET382150"), the curable adhesive obtained in Preparation Example 1 was coated to a thickness of 10 μm and cut into rectangles of 250 mm × 320 mm to create an adhesive sheet with a curable adhesive layer (hereinafter sometimes referred to as the adhesive layer). As a conductive wire, the silver sulfide-plated tungsten wire (hereinafter sometimes referred to as the wire) prepared above was prepared. Next, the adhesive sheet obtained above was wound around a drum component with the adhesive layer surface facing outwards and without wrinkles, and the two ends of the adhesive sheet in the circumferential direction were fixed with double-sided tape. The wire wound on the spool was attached to the surface of the adhesive layer of the adhesive sheet located near the end of the drum component, and then the wire was released while being wound around the drum component, moving the drum component little by little in a direction parallel to the drum axis, while the wire was wound around the drum component in spirals drawn at equal intervals of 3 mm. Thus, a wiring harness is formed with 96 wires arranged on the surface of the adhesive layer. The wires are then cut, and the wiring harness is removed from the drum assembly. The wiring harness is cut into 40mm × 82mm width pieces, with 12 wires removed at a time, to create wiring harness sheets. The overall axial resistance r of the conductive wire is 4.93Ω.

[0165] (Fabrication of electrode substrate)

[0166] For 2mm thick glass, a silver paste (manufactured by Jujo Chemical Co., Ltd., product name "#2TF silver paste") was screen-printed with a width of 3mm and an electrode spacing of 7.8mm. The paste was then dried at 150°C for 30 minutes to form a 12μm thick coating, creating a substrate with electrodes. Next, a nickel layer (thickness: 1μm) and a gold layer (thickness: 50nm) were sequentially layered on the silver paste using chemical plating to create a substrate with electrodes (resistance R: 0.56Ω). The elastic modulus of the electrodes was 62.6 GPa.

[0167] (Preparation of the composition for coating layer formation)

[0168] As an infrared transmitting ink, a visible light absorbing infrared transmitting ink (manufactured by Jujo Chemical Co., Ltd., product name "TG-IR ink PB-A black") was prepared. This infrared transmitting ink contains perylene pigments. A composition for forming a coating layer is obtained by combining 2 parts by mass of 3-aminopropyltrimethoxysilane and 5 parts by mass of trimethylolpropane-xylene diisocyanate with 100 parts by mass of this infrared transmitting ink.

[0169] (Fabrication of substrate with coating)

[0170] A coating film is formed on the side of the electrode-bearing substrate opposite to the side where the electrodes are located by screen printing the prepared coating layer forming composition. Then, the coating film is dried under a two-stage drying condition: first at 90°C for 10 minutes, then at 150°C for 30 minutes, thereby forming a 6 μm thick coating layer on the substrate. Furthermore, the coating layer formed by the coating layer forming composition is black in color, and has a maximum transmittance of 89% and a minimum transmittance of 86% for near-infrared light with wavelengths from 905 nm to 1000 nm, and a maximum transmittance of 5% and a minimum transmittance of 0% for visible light with wavelengths from 380 nm to 700 nm. Additionally, the refractive index for near-infrared light with a wavelength of 905 nm is 2.10.

[0171] (Panel board fabrication)

[0172] The fabricated wiring sheet was attached to an electrode-bearing substrate with electrodes at both ends of the wire. Then, it was heated at 120°C, 0.5 MPa, and for 30 minutes to obtain the wiring board of Example 1.

[0173] (Production of protective film)

[0174] The adhesive composition obtained in Preparation Example 3 was coated onto a 100 μm thick cyclic olefin polymer film (manufactured by Zeon Corporation, Japan, product name "ZF16") and cut into rectangles of 50 mm × 120 mm. Then, a circle with a diameter of 5 mm was cut out with a center-to-center distance of 7.8 mm between two circles to make a protective sheet.

[0175] (Making a patch panel with a protective cover)

[0176] For the wiring board, the protective sheet is attached by aligning the electrodes of the wiring board with the circle of the protective sheet. Then, at an illuminance of 200mW / cm²... 2 Light intensity 1000mJ / cm 2 Under certain conditions, a wiring board with a protective sheet was obtained by irradiating it with ultraviolet light with a wavelength of 365nm.

[0177] [Example 2]

[0178] In the fabrication of the wiring harness, palladium-plated tungsten wire (12 μm in diameter, volume resistivity 5.5 × 10⁻⁶) is used as the conductive wire. -8 The palladium-plated tungsten wire (Ω·m) was used instead of the silver sulfide-plated tungsten wire. Otherwise, the wiring board with a protective sheet was made in the same manner as in Example 1. The palladium-plated tungsten wire had a near-black hue.

[0179] [Example 3]

[0180] In the fabrication of the wiring sheet, copper oxide-palladium-tungsten wire was used as the conductive linear material instead of silver sulfide-plated tungsten wire. Otherwise, a wiring board with a protective sheet was fabricated in the same manner as in Example 1. The copper oxide-palladium-tungsten wire has a near-black hue. The copper oxide-palladium-tungsten wire was fabricated as follows.

[0181] A copper-plated tungsten wire (12 μm in diameter, volume resistivity 4.23 × 10⁻⁶) was immersed in a palladium-containing plating solution (“OPC BLACK COPPER”, manufactured by Okuno Pharmaceutical Co., Ltd.) -8 The copper oxide-palladium-plated tungsten wire is then treated with an anti-discoloration agent (“OPCBLACK Keep”, manufactured by Okuno Pharmaceutical Co., Ltd.) to produce a copper oxide-palladium-plated tungsten wire. The copper oxide-palladium-plated tungsten wire has a coating in which copper oxide and palladium are mixed. Furthermore, the thickness of the copper oxide-palladium plating layer in the produced copper oxide-palladium-plated tungsten wire is 0.2 μm.

[0182] [Comparative Example 1]

[0183] In the fabrication of the wiring harness, carbon-coated tungsten wire (12 μm in diameter, volume resistivity 5.5 × 10⁻⁶) is used as the conductive wire. -8 Instead of silver sulfide-plated tungsten wire, a protective sheet-coated wiring board was fabricated in the same manner as in Example 1. The carbon-coated tungsten wire has a near-black hue.

[0184] [Comparative Example 2]

[0185] In the fabrication of the wiring harness, gold-plated tungsten wire (12 μm in diameter, volume resistivity 5.5 × 10⁻⁶) is used as the conductive wire. -8 Instead of silver sulfide-plated tungsten wire, a gold-plated tungsten wire (Ω·m) was used, and the wiring board with a protective sheet was fabricated in the same manner as in Example 1. The gold-plated tungsten wire was not a near-black hue.

[0186] [Table 1]

[0187]

[0188] Compared with the wiring boards obtained in the comparative examples, the wiring boards obtained in each embodiment showed good results in both reflectivity and resistance evaluation. Furthermore, the embodiments with low resistance change rate and low infrared reflectivity demonstrated good appearance and excellent designability.

[0189] Figure 3 The graph shows the relationship between time and the rate of change of resistance when the wiring board is placed in an environment with a temperature of 85°C and a relative humidity of 85%RH. Figure 3 In the diagram, the horizontal axis represents the placement time, and the vertical axis represents the rate of change of resistance value. Figure 3 In the diagram, E represents the wiring board fabricated in Example 1, and C represents the wiring board fabricated in Comparative Example 1. Figure 3 As shown, the resistance value of the wiring board made in Example 1 changes more rapidly over time compared to the wiring board made in Comparative Example 1.

[0190] The results above confirm that the wiring board according to this embodiment can achieve blackening of conductive wires and suppress corrosion in humid and hot environments.

[0191] Explanation of reference numerals in the attached figures

[0192] 1: Substrate

[0193] 2: Wiring unit

[0194] 21: Conductive linear material

[0195] 3: Resin layer

[0196] 4: Electrode

[0197] 100: Patch panel

Claims

1. A wiring board, characterized in that, have: A wiring harness, which is a conductive wire-like body; A pair of electrodes that are in direct contact with the conductive wire. The infrared reflectance of the conductive linear body at a wavelength of 1000 nm is greater than 0% and less than 90%. The resistance value changes by less than 50% after standing for 1000 hours in a humid and hot environment of 85℃ and 85%RH.

2. The wiring board according to claim 1, characterized in that, The relationship between the axial resistance R of the electrode and the overall axial resistance r of the conductive linear body satisfies the condition expressed by the following mathematical formula (F1). r>R···(F1) 3. The wiring board according to claim 1 or 2, characterized in that, It also has a resin layer that directly or indirectly supports the wiring.

4. The wiring board according to claim 1 or 2, characterized in that, The maximum width of the electrode is more than 1 mm and less than 10 mm.

5. The wiring board according to claim 1 or 2, characterized in that, The wiring harness has a structure in which the conductive linear bodies are arranged at intervals.

6. The wiring board according to claim 1 or 2, characterized in that, The wiring harness consists of only one conductive wire.

7. The wiring board according to claim 1 or 2, characterized in that, The conductive linear body is covered with sulfide or palladium.

8. The wiring board according to claim 1 or 2, characterized in that, The conductive linear body is covered with silver sulfide.

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