WO2025205677A1 - Wiring sheet - Google Patents

Abstract

This wiring sheet (100) comprises a wiring body (2) provided with electrically conductive linear bodies (21), and a pair of electrodes (4) that are in direct contact with the electrically conductive linear bodies (21), wherein the electrically conductive linear bodies (21) have an infrared reflectance of 0% to 90% inclusive at a wavelength of 1000 nm, and have a rate of change in resistance value of 50% or less after being allowed to stand for 1000 hours in a hot, humid environment at a temperature of 85°C and a relative humidity of 85% RH.

Description

Wiring sheet

The present invention relates to a wiring sheet.

Wiring sheets equipped with wiring bodies are known. These wiring sheets can be used, for example, as materials for heat-generating textiles, components that generate heat in various items, and heating elements in heat-generating devices used in sensors and the like.

Patent Document 1 discloses a wiring sheet equipped with a contact sensor. The sensor disclosed in Patent Document 1 is a contact sensor comprising a pseudo-sheet structure in which a plurality of conductive linear bodies are arranged at intervals, a first electrode electrically connected to the conductive linear bodies, and a second electrode disposed at a distance from the pseudo-sheet structure and the first electrode, which intersects with the conductive linear bodies but does not overlap with the first electrode in a plan view of the pseudo-sheet structure.

Patent Document 2 discloses a pressure-sensitive heating element having a pressure-sensitive heating section made of a foamed conductive material. In the pressure-sensitive heating element disclosed in Patent Document 2, the pressure-sensitive heating section generates heat when electricity is applied, and elastically deforms when subjected to a compressive load. When electricity is applied and the compressive load is applied, the amount of heat generated increases as the compressive load increases. The pressure-sensitive heating element disclosed in Patent Document 2 is also provided with a conductive cloth.

Patent Document 3 discloses a transparent film heater having a transparent heat-generating layer on the surface of a transparent film substrate. In the transparent film heater disclosed in Patent Document 3, the transparent heat-generating layer contains at least metal nanowires.

International Publication No. 2023/063377 Japanese Patent Application Laid-Open No. 2019-204674 JP 2010-103041 A

For example, the wiring sheet in Patent Document 1 uses gold-plated linear elements. The wiring sheet disclosed in Patent Document 1 has high corrosion resistance even when used or stored in a humid and hot environment.

However, there are cases where wiring sheets are required to be constructed with, for example, a more aesthetically pleasing design. Furthermore, there are cases where wiring sheets are required to be constructed with a design that is more suitable for use as heaters for optical sensors such as LiDAR (Light Detection and Ranging or Laser Imaging Detection and Ranging). To meet these demands, it is conceivable to, for example, color the components used in wiring sheets that allow electricity to flow black.

The pressure-sensitive heating element disclosed in Patent Document 2 uses a carbon-coated copper-nickel plated woven fabric as the conductive fabric that enables electrical conduction. 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 a carbon-coated copper-nickel plated woven fabric. For this reason, the pressure-sensitive heating element of Patent Document 2 has low corrosion resistance in humid and hot environments. The transparent film heater of Patent Document 3 uses silver nanowires. It is disclosed that the silver nanowires used in the transparent film heater of Patent Document 3 are made of a silver alloy for sulfide stability. These silver nanowires are not blackened. Furthermore, the silver nanowires of Patent Document 3 have poor corrosion stability when used or stored in a humid and hot environment.

For example, in a wiring body such as that disclosed in Patent Document 1, it is believed that a wiring body with a more aesthetically pleasing design can be obtained by replacing the conductive linear bodies with the carbon-coated linear bodies disclosed in Patent Document 2. However, if a wiring sheet is made using carbon-coated linear bodies, there is a concern that corrosion may occur in the wiring sheet when it is used or stored in a humid and hot environment, for example, and the resistance value of the wiring sheet may increase.

The object of the present invention is to provide a wiring sheet that can blacken conductive linear bodies while suppressing corrosion in humid and hot environments.

[1] A wiring body including a conductive linear body;
a pair of electrodes in direct contact with the conductive linear body;
Equipped with
the conductive linear body has an infrared reflectance of 0% or more and 90% or less at a wavelength of 1000 nm;
The rate of change in resistance value after leaving the capacitor for 1000 hours in a humid and hot environment at a temperature of 85°C and a relative humidity of 85% RH is 50% or less.
Wiring sheet.

[2] The wiring sheet according to [1],
a relationship between a resistance value R of the electrode in the axial direction and a total resistance value r of the conductive linear body in the axial direction satisfies the condition expressed by the following formula (F1):
Wiring sheet.
r>R...(F1)

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

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

[5] The wiring sheet according to any one of [1] to [4],
The wiring body has a structure in which the conductive linear bodies are arranged at intervals.
Wiring sheet.

[6] The wiring sheet according to any one of [1] to [5],
The wiring body is composed of only one of the conductive linear bodies.
Wiring sheet.

[7] The wiring sheet according to any one of [1] to [6],
The conductive linear body is coated with sulfide or palladium.
Wiring sheet.

[8] The wiring sheet according to any one of [1] to [7],
The conductive linear body is coated with silver sulfide.
Wiring sheet.

One aspect of the present invention provides a wiring sheet that can suppress corrosion in humid and hot environments while achieving black coloring of conductive linear bodies compared to conventional wiring sheets.

1 is a schematic diagram illustrating a wiring sheet according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing the II-II cross section of FIG. 10 is a graph showing the relationship between the rate of change in resistance value and the time period when left in a humid and hot environment.

[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.

[Wiring sheet]
As shown in Figures 1 and 2, the wiring sheet 100 according to this embodiment includes a wiring body 2 and a pair of electrodes 4. The wiring body 2 includes a conductive linear body 21. The pair of electrodes 4 are in direct contact with the conductive linear body 21. The conductive linear body 21 has an infrared reflectance of 0% or more and 90% or less at a wavelength of 1000 nm. Furthermore, the wiring sheet 100 exhibits a resistance change rate of 50% or less after being left for 1000 hours in a humid and hot environment at a temperature of 85°C and a relative humidity of 85% RH.

As shown in Figures 1 and 2, the wiring sheet 100 further includes a substrate 1 and a resin layer 3. In the wiring sheet 100, the wiring body 2 has a structure in which conductive linear bodies 21 are arranged. The resin layer 3 also supports the wiring body 2 directly or indirectly.

The inventors speculate as follows as to why the wiring sheet 100 according to this embodiment, having the above-described configuration, is able to blacken the conductive linear members 21 while suppressing corrosion in a humid and hot environment. By reducing the infrared reflectivity of the conductive linear members 21 used in the wiring sheet 100 to a value lower than conventional values, diffuse reflection of light from the conductive linear members 21 is suppressed, thereby enabling the blackening of the conductive linear members 21. For example, blackening can be achieved when carbon-coated conductive linear members are used. However, when carbon-coated conductive linear members are used, the wiring sheet has low durability to humid and hot conditions, resulting in a significant change in the resistance value of the wiring sheet. The wiring sheet 100 has a structure in which the conductive linear members 21 are arranged at intervals. When carbon-coated conductive linear members are used as the conductive linear members of a wiring sheet having such a structure, corrosion occurs in the conductive linear members when the wiring sheet is used or stored in a humid and hot environment, resulting in a large rate of change in the resistance value of the wiring sheet. Meanwhile, in the wiring sheet 100 according to this embodiment, the conductive linear members 21 are configured so that their infrared reflectance at a wavelength of 1000 nm is in the range of 0% to 90%. This allows the conductive linear members 21 to be blackened. Furthermore, the wiring sheet 100 according to this embodiment is configured so that the rate of change in resistance after being left for 1000 hours in a humid and hot environment at a temperature of 85°C and a relative humidity of 85% RH is in the range of 50% or less. This improves the corrosion resistance of the conductive linear members 21 in a humid and hot environment. As a result, the wiring sheet 100 according to this embodiment can suppress corrosion in a humid and hot environment while achieving blackening of the conductive linear members 21.

(Base material)
The substrate 1 can directly or indirectly support the wiring body 2. The substrate 1 is not necessarily 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, from the viewpoint of strength or handleability, the material for the substrate 1 is preferably resin or glass. Examples of resins used for the substrate 1 include polyethylene, polypropylene, polystyrene, polycarbonate, and polyacetal.

The substrate 1 may or may not contain a colorant. The colorant allows the visible light and near-infrared light transmittance of the wiring sheet 100 to be adjusted to within the desired range. The colorant may be contained inside the substrate 1, or may be contained in a coating layer (not shown) provided on the outside of the substrate 1. The coating layer is a layer that is provided as needed.

When the wiring sheet 100 includes a covering layer (not shown) on the outside of the substrate 1, the covering layer is provided on at least one surface of the substrate 1. That is, the covering layer may be provided, for example, on the surface of the substrate 1 on which the pair of electrodes 4 are provided, or on the surface of the substrate 1 opposite the side on which the pair of electrodes 4 are provided. The covering layer may be provided in direct contact with the substrate 1. When the covering layer is provided on the surface of the substrate 1 on which the pair of electrodes 4 are provided, the pair of electrodes 4 may be provided in direct contact with the covering layer.

If the substrate 1 has a coating layer, the coating layer preferably has a visible light transmittance of 10% or less for wavelengths from 380 nm to 700 nm. The visible light transmittance of the coating layer for wavelengths from 380 nm to 700 nm is more preferably 8% or less, and even more preferably 6% or less. The hue of the coating layer is not particularly limited as long as the visible light transmittance in the wavelength range of 380 nm to 700 nm can be adjusted to 10% or less. The coating layer is preferably colored, for example, black. Black may be any hue that is generally recognized as black. When the coating layer is colored black, it may be colored black using, for example, an infrared-transparent ink containing a single type of colorant, an infrared-transparent ink containing two or more types of colorant, or multiple infrared-transparent inks of different colors. It is preferable that the visible light transmittance of the coating layer for wavelengths from 380 nm to 700 nm be such that the maximum visible light transmittance in that wavelength range is within the above range.

The covering layer preferably has a desired infrared transmittance and a refractive index of at least a certain level, from the viewpoint of facilitating application to, for example, optical sensing technology.
The refractive index of the coating layer at a wavelength of 905 nm is preferably 1.65 or more, more preferably 1.75 or more, and even more preferably 1.85 or more. A refractive index of the coating layer of 1.65 or more makes the wiring sheet 100 suitable for use as, for example, an optical sensor component used in optical sensing technology. The upper limit of the refractive index of the coating layer at a wavelength of 905 nm is not particularly limited, and is preferably 3.00 or less, more preferably 2.70 or less, and even more preferably 2.40 or less.

The coating layer preferably contains infrared-transparent ink. The coating layer preferably has a transmittance of 70% or more for near-infrared rays with wavelengths of 905 nm to 1000 nm. Infrared-transparent ink is an ink that transmits near-infrared rays in the wavelength range of 905 nm to 1000 nm, while suppressing the transmission of visible light and ultraviolet rays. The infrared-transparent ink can transmit, for example, 70% or more of near-infrared rays in the wavelength range of 905 nm to 1000 nm. The transmittance of near-infrared rays with wavelengths of 905 nm to 1000 nm in a coating layer containing infrared-transparent ink is more preferably 75% or more, even more preferably 80% or more, and even more preferably 85% or more. The transmittance of near-infrared rays with wavelengths of 905 nm to 1000 nm in a coating layer containing infrared-transparent ink may be less than 100%, may be 99% or less, or may be 95% or less. If the coating layer contains infrared-transmitting ink and the transmittance of the coating layer for near-infrared rays with wavelengths of 905 nm to 1000 nm is 70% or higher, the wiring sheet 100 can be easily used as a component for an optical sensor, for example. It is preferable that the transmittance of the coating layer for near-infrared rays with wavelengths of 905 nm to 1000 nm be such that the minimum value of the near-infrared transmittance in that wavelength range is within the above range.

The infrared-transmitting ink contains, for example, a colorant and a resin component. The infrared-transmitting ink preferably contains additives as necessary. The colorant may contain at least one of a dye and a colored pigment. The colorant preferably contains a colored pigment. The colored pigment is not particularly limited, and examples include inorganic pigments and organic pigments, which can be used alone or in combination. The inorganic pigment is not particularly limited, and examples include bismuth sulfide, carbon black, red iron oxide, cadmium red, Prussian blue, and ultramarine blue, and these can be used alone or in combination of two or more. The organic pigment is not particularly limited and may include, for example, lactam black pigments, perylene pigments, phthalocyanine pigments, benzofuranone pigments, azo pigments, anthraquinone pigments, indanthrene pigments, isoindolinone pigments, quinacridone pigments, quinophthalone pigments, diketopyrrolopyrrole pigments, dioxazine pigments, and thioindigo pigments. These pigments may be used alone or in combination. Among these, the coloring pigment is preferably an organic pigment. From the viewpoint of enhancing the clarity of the image of the object obtained by irradiating the object with laser light, it is preferable to include at least one pigment selected from the group consisting of perylene pigments and phthalocyanine pigments, which can be set to have a low refractive index and suppress light scattering. Furthermore, by including at least one pigment selected from the group consisting of perylene pigments and phthalocyanine pigments in the infrared-transmitting ink, it is possible to suppress the visible light transmittance of the coating layer while easily achieving infrared transmittance.

The perylene-based pigment is not particularly limited as long as it is an organic pigment having a perylene skeleton. For example, a perylene-based pigment has a structure in which two oxygen atoms constituting a six-membered ring of perylene tetracarboxylic dianhydride have been removed. Specific 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.

The phthalocyanine pigment is not particularly limited as long as it is an organic pigment having a phthalocyanine skeleton. For example, the phthalocyanine pigment has a cyclic structure in which four phthalic acid imides are bridged by nitrogen atoms. The phthalocyanine pigment may have a coordinated metal. Examples of the coordinated metal include copper, magnesium, titanium, iron, cobalt, nickel, zinc, and aluminum. When the phthalocyanine pigment contains a coordinated metal, the phthalocyanine pigment may be a copper phthalocyanine pigment in which copper is coordinated. Specific examples of the phthalocyanine pigment include phthalocyanine blue and phthalocyanine green. The phthalocyanine pigments can be used alone or in combination of two or more.

The resin component is not particularly limited and may include, for example, various resins such as acrylic resins, vinyl chloride resins, butyral resins, polyester resins, polyurethane resins, cellulose resins, and epoxy resins, and one or more of these may be used in combination. It is preferable that the resin component includes an acrylic resin. It is also preferable that the resin component is an acrylic resin.

If necessary, the infrared transparent ink may contain at least one additive such as a surfactant, surface conditioner, defoamer, leveling agent, curing accelerator, dispersant, light stabilizer, flow conditioner, polymerization inhibitor, and oxidation polymerization inhibitor.

There are no particular restrictions 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.

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

(Wiring body)
The wiring body 2 includes conductive linear bodies 21. In the wiring sheet 100, the wiring body 2 has a structure in which the conductive linear bodies 21 are arranged. Furthermore, in the wiring sheet 100, the wiring body 2 has a structure in which a plurality of the conductive linear bodies 21 are arranged in parallel. In the wiring sheet 100, the wiring body 2 has a structure in which the plurality of conductive linear bodies 21 are arranged at intervals from one another. However, the wiring sheet 100 according to the present embodiment is a preferred example, and is not limited to this. The wiring body 2 does not have to have a structure in which the plurality of conductive linear bodies 21 are arranged at intervals from one another. The wiring body 2 may have a structure consisting of only one conductive linear body 21. When the wiring body 2 is composed of one conductive linear body 21, the wiring body 2 may have a pattern in which the single conductive linear body 21 has at least one bent portion.

In the wiring sheet 100, the conductive linear members 21 are linear when viewed in a plan view of the wiring sheet 100. However, this is not limiting, and the conductive linear members 21 may be wavy when viewed in a plan view of the wiring sheet 100. Examples of wavy shapes include a sine wave, a rectangular wave, a triangular wave, and a sawtooth wave. For example, if the wiring member 2 has such a wavy structure, breakage of the conductive linear members 21 can be suppressed when the wiring sheet 100 is stretched in the axial direction of the conductive linear members 21.

The volume resistivity of the conductive linear body 21 is preferably 1.0×10 ⁻⁹ Ω·m or more, more preferably 3.0×10 ⁻⁹ Ω·m or more, and even more preferably 1.0×10 ⁻⁸ Ω·m or more. The volume resistivity of the conductive linear body 21 is preferably 1.0×10 ⁻³ Ω·m or less, more preferably 1.0×10 ⁻⁴ Ω·m or less, and even more preferably 5.0×10 ⁻⁵ Ω·m or less. When the volume resistivity of the conductive linear body 21 is within the above range, the surface resistance of the wiring body 2 is likely to decrease.
The 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 section 40 mm from the end, and the resistance of the end and the section 40 mm from the end was measured. The volume resistivity of the conductive linear body 21 was then calculated by multiplying the resistance value by the cross-sectional area (unit: ^m2 ) of the conductive linear body 21 and dividing the obtained value by the measured length (0.04 m).

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

When the cross section of the conductive linear body 21 is circular, the diameter D (see FIG. 2 ) of the conductive linear body 21 is preferably 3 μm or more and 200 μm or less. From the 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 body 21 is more preferably 4 μm or more, and even more preferably 5 μm or more. The diameter D of the conductive linear body 21 is more preferably 150 μm or less, even more preferably 100 μm or less, even more preferably 50 μm or less, and even more preferably 20 μm or less.
When the cross section of the conductive linear body 21 is elliptical, it is preferable that the major axis is in the same range as the diameter D described above.

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 taking the average value.

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

The distance L between the conductive linear members 21 is measured by, for example, observing the conductive linear members 21 of the wiring body 2 using a digital microscope and measuring the distance between two adjacent conductive linear members 21 .
The interval between two adjacent conductive linear bodies 21 is the length along the direction in which the conductive linear bodies 21 are arranged, and is the length between opposing portions of the two conductive linear bodies 21 (see FIG. 2 ). When the conductive linear bodies 21 are arranged at uneven intervals, the interval L is the average value of the intervals between all adjacent conductive linear bodies 21.

There are no particular restrictions on the form of the conductive linear body 21 as long as it satisfies both of the following conditions (a) and (b): Condition (a) The infrared reflectance of the conductive linear body 21 at a wavelength of 1000 nm is 0% or more and 90% or less. Condition (b) The rate of change in resistance of the wiring sheet 100 after being left for 1000 hours in a humid and hot environment at a temperature of 85°C and a relative humidity of 85% RH is 50% or less.

The conductive linear body 21 can be produced by, for example, etching, screen printing, inkjet printing, or the like. The conductive linear body 21 is preferably a linear body including a metal wire (hereinafter also referred to as a "metal wire linear body"). Metal wire has high thermal conductivity, high electrical conductivity, 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, it can still pass the current required to heat the wiring sheet 100. This makes it possible to make the conductive linear body 21 less visible. In other words, using a metal wire linear body as the conductive linear body 21 reduces the resistance value of the wiring body 2 while improving light transmittance. Furthermore, the wiring sheet 100 is more likely to generate heat quickly. Furthermore, as described above, it is easy to obtain linear bodies with a small diameter.

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. In particular, wires containing one or more metals selected from tungsten and molybdenum, and alloys containing these, are preferred from the viewpoint of low volume resistivity.

From the viewpoint of achieving blackening of the conductive linear body 21 and suppressing corrosion of the wiring sheet 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, a coating with sulfide may be referred to as sulfide coating, and a coating with palladium may be referred to as palladium coating. A linear body coated with sulfide or palladium may (i) be a linear body directly coated with sulfide or palladium, (ii) be a linear body coated with sulfide or palladium via a coating of a material other than sulfide or a material other than palladium, or (iii) be coated with 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 linear body coated with palladium is a metal wire, the metal wire may be directly coated with palladium alone, the metal wire may be coated with palladium alone via a coating of a metal other than palladium or a metal oxide, or the metal wire may be coated with a mixture of palladium and a metal other than palladium or a metal oxide. From the viewpoint of further achieving blackening of the conductive linear body 21 and further suppressing corrosion of the wiring sheet 100 in a humid and hot environment, the conductive linear body 21 is preferably coated with silver sulfide. It is also preferable that the conductive linear body 21 be coated with a mixture of palladium and a metal other than palladium or a metal oxide. If the conductive linear body 21 is coated with sulfide or palladium, the metallic luster is reduced, making it easier to make the metal wire less noticeable. Furthermore, if the metal wire is coated with sulfide or palladium, metal corrosion is more likely to be suppressed, making it easier to satisfy both conditions (a) and (b). When the conductive linear body 21 is coated with a sulfide or 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 may be, for example, a sulfide-plated linear body or a palladium-plated linear body. Among these, the conductive linear body 21 is preferably a silver sulfide-plated linear body. It is also preferable that the conductive linear body 21 be a linear body plated with a mixture of palladium and a metal or metal oxide other than palladium. The metal or metal oxide mixed with palladium is not particularly limited, and examples include one or more selected from the group consisting of copper, silver, and oxides of these metals.

The infrared reflectance of the conductive linear body 21 at a wavelength of 1000 nm is 0% or more and 90% or less. 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, even 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 may be 1% or more, 3% or more, 6% or more, 8% or more, or 10% or more.

The infrared reflectance of the conductive linear body 21 at a wavelength of 1000 nm can be measured using the method described in the Examples below.

(Resin layer)
The resin layer 3 directly or indirectly supports the wiring body 2. The resin layer 3 is not necessarily provided. The resin layer 3 is a component that is provided as needed. The resin layer 3 stabilizes the resistance value of the wiring body 2. That is, the resin layer 3 fixes the conductive linear body 21, stabilizes the contact between the conductive linear body 21 and the electrode 4, and makes it less likely that an increase in resistance value will occur.

The thickness of the resin layer 3 is not particularly limited. It may be equal to or greater than the diameter D of the conductive linear body 21, or it may be less than the diameter D of the conductive linear body 21. If the thickness of the resin layer 3 is equal to or greater than the diameter D of the conductive linear body 21, the wiring body 2 can be contained within the resin layer 3. If the thickness of the resin layer 3 is less than the diameter D of the conductive linear body 21, the wiring body 2 is exposed from the resin layer 3. Furthermore, if the wiring body 2 is exposed from the resin layer 3, it may be exposed on the side of the substrate 1 or on the side opposite the substrate 1. The thickness of the resin layer 3 is preferably 1 μm or greater, more preferably 3 μm or greater, and even more preferably 5 μm or greater. 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.

From the viewpoint of increasing the storage modulus, the resin layer 3 is preferably a layer made of a cured product of a curable adhesive.
Examples of 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.

The thermosetting 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 as thermosetting resins, as they are suitable 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, as they exhibit excellent curing properties. Epoxy resins are preferred.

As epoxy resins, aromatic epoxy resins or cyclic epoxy resins such as alicyclic epoxy resins are preferred from the perspective of increasing the storage modulus of resin layer 3. Epoxy resins with flexible segments such as oxyalkylene chains tend to decrease the storage modulus of resin layer 3.

The energy ray-curable adhesive preferably contains an energy ray-curable resin. Examples of energy ray-curable resins include compounds having at least one polymerizable double bond in the molecule, and are preferably acrylate compounds having a (meth)acryloyl group.

Examples of acrylate compounds include dicyclopentadiene diacrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate. (meth)acrylates containing a chain aliphatic skeleton such as dicyclopentanyl di(meth)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.

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

The adhesive may contain only one type of energy ray-curable resin, or two or more types. If two or more types of energy ray-curable resins are used, the combination and ratio of these resins can be selected as desired.

When using an energy ray-curable resin or a thermosetting resin, it is preferable to use a photopolymerization initiator or a thermal polymerization initiator. By using a photopolymerization initiator or a thermal polymerization initiator, the polymerization reaction of the curable resin can be easily initiated, making it easier to control the curing reaction.

Photopolymerization initiators include photoradical polymerization initiators such as benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, 2-chloroanthraquinone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

In addition to photoradical polymerization initiators, photocationic polymerization initiators can also be used. Photocationic polymerization initiators are compounds that generate cationic species when irradiated with energy rays, initiating the curing reaction of cationic curable compounds. They consist of a cationic moiety that absorbs energy rays and an anionic moiety that serves as an acid generation source.

Examples of cationic photopolymerization initiators include sulfonium salt compounds, iodonium salt compounds, phosphonium salt compounds, ammonium salt compounds, antimonate compounds, diazonium salt compounds, selenium salt compounds, oxonium salt compounds, and bromine salt compounds. Among these, from the viewpoints of excellent compatibility and excellent storage stability of the resulting adhesive, the cationic photopolymerization initiator is preferably a sulfonium salt compound, and more preferably an aromatic sulfonium salt compound having an aromatic group.

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

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

Phosphonium salt compounds include tri-n-butyl(2,5-dihydroxyphenyl)phosphonium bromide and hexadecyltributylphosphonium chloride.

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

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

Thermal polymerization initiators include peroxodisulfates such as hydrogen peroxide, ammonium peroxodisulfate, sodium peroxodisulfate, and potassium peroxodisulfate; azo compounds such as 2,2'-azobis(2-amidinopropane) dihydrochloride, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobisisobutyronitrile, and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile); and 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.

In addition to the above-mentioned thermal radical polymerization initiators, thermal cationic polymerization initiators can also be used as thermal polymerization initiators. Thermal cationic polymerization initiators are compounds that, when heated, can generate cationic species that initiate polymerization. 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 as the thermal cationic polymerization initiator, as they are easily available and can easily produce a resin layer 3 with superior adhesion and transparency.

Sulfonium salts include triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, benzyl(4-hydroxyphenyl)methylsulfonium tetrakis(pentafluorophenyl)borate, (4-hydroxyphenyl)methyl(4-methylbenzyl)sulfonium tetrakis(pentafluorophenyl)borate, and triphenylsulfonium hexafluoroarsinate.

Quaternary ammonium salts include tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, and tetrabutylammonium hydrogen sulfate. Phosphonium salts include ethyltriphenylphosphonium hexafluoroantimonate and tetrabutylphosphonium hexafluoroantimonate.

Diazonium salts include benzenediazonium chloride. Iodonium salts include diphenyliodonium hexafluoroarsinate, bis(4-chlorophenyl)iodonium hexafluoroarsinate, bis(4-bromophenyl)iodonium hexafluoroarsinate, and phenyl(4-methoxyphenyl)iodonium hexafluoroarsinate.

These polymerization initiators may be used alone or in combination of two or more.
When forming a crosslinked structure using these polymerization initiators, the amount used is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.3 parts by mass or more and 20 parts by mass or less, and particularly preferably 0.5 parts by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the energy ray-curable resin or the thermosetting resin.

If a thermosetting resin is used, a curing catalyst such as an imidazole-based curing catalyst may also be used.

In this embodiment, the curable adhesive may contain, in addition to the energy ray-curable resin or thermosetting resin, a flexibility-adjusting component to facilitate maintaining the sheet shape before curing. Examples of polymers that can be used as flexibility-adjusting components include phenoxy resin, polyolefin resin or modified polyolefin resin, polyamide-imide resin, polyimide resin, rubber-based resin, and acrylic resin.

These softness-adjusting ingredients can be used alone or in combination of two or more.

When the curable adhesive used in this embodiment contains a flexibility-adjusting component, the total amount of energy ray-curable resin or thermosetting resin contained in the adhesive is, from the viewpoint of adjusting the storage modulus of the resin layer 3, 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. Furthermore, when the adhesive contains an energy ray-curable resin or thermosetting resin but does not contain a flexibility-adjusting component, the storage modulus of the resin layer 3 tends to be too high.

In this embodiment, the curable adhesive may or may not contain a filler. From the viewpoint of increasing the storage modulus of the resin layer 3 at 23°C, the curable adhesive may contain a filler. From the viewpoint of suppressing an increase in the storage modulus of the resin layer 3 at 23°C, the curable adhesive may not contain a filler.

Fillers include, for example, inorganic powders such as silica, alumina, talc, calcium carbonate, titanium white, red iron oxide, silicon carbide, and boron nitride; beads made by spheroidizing inorganic powders, single-crystal fibers, and glass fibers. Of these, silica filler and alumina filler are preferred. Fillers may be used alone or in combination of two or more types.

The curable adhesive may contain other components. Examples of other components include well-known additives such as organic solvents, coupling agents, flame retardants, tackifiers, UV absorbers, antioxidants, preservatives, antifungal agents, plasticizers, antifoaming agents, and wettability adjusters.

(electrode)
The electrodes 4 are used to supply current to the conductive linear body 21. The electrodes 4 are in a pair. The electrodes 4 are in direct contact with the conductive linear body 21. The electrodes 4 are disposed so as to be electrically connected to both ends of the conductive linear body 21.

It is preferable that the relationship between the resistance value R of the electrode 4 in the axial direction and the overall resistance value r of the conductive linear body 21 in the axial direction satisfies the condition expressed by the following formula (F1). When the condition expressed by the following formula (F1) is satisfied, heat generation of the electrode 4 can be reduced.
r>R...(F1)

The value of R/r is preferably 0.0001 or greater, and more preferably 0.0005 or greater. Furthermore, R/r is preferably 0.3 or less, and more preferably 0.15 or less. When using wiring sheet 100 as a heating element, wiring body 2 needs to have a certain degree of resistance in order to generate heat, while electrodes 4 preferably allow current to flow as easily as possible.

The resistance value R in the axial direction of the electrode 4 and the overall resistance value r in the axial direction of the conductive linear body 21 can be measured using a tester. First, the resistance value R in the axial direction of the electrode 4 and the resistance value (per wire) in the axial direction of the conductive linear body 21 are measured. Since the resistance value in the axial direction of the conductive linear body 21 is inversely proportional to the cross-sectional area of the conductive linear body 21, the overall resistance value r in the axial direction of the conductive linear body 21 can be calculated by dividing the resistance value (per wire) in the axial direction of the conductive linear body 21 by the number of conductive linear bodies 21.

The Young's modulus of the electrode 4 is preferably more than 1×10 ⁹ Pa and not more than 1×10 ¹¹ Pa. If the Young's modulus of the electrode 4 is 1×10 ¹¹ Pa or less, the contact resistance between the conductive linear body 21 and the electrode 4 tends to be smaller. From the same viewpoint, the Young's modulus of the electrode 4 is more preferably 8.5×10 ¹⁰ Pa or less, and even more preferably 7×10 ¹⁰ Pa or less. The Young's modulus of the electrode 4 may be 2×10 ⁹ Pa or more, 3×10 ⁹ Pa or more, or 5×10 ⁹ Pa or more.

The Young's modulus of the electrode 4 can be measured by a continuous stiffness measurement method. For example, the Young's modulus of the electrode 4 provided on a glass substrate at 25° C. can be measured using a nanoindenter (manufactured by MTS Systems) under the following conditions.
Indenter shape: triangular pyramid Maximum indenter depth: 500 nm
Vibration frequency: 75Hz

The maximum thickness of the electrode 4 is preferably 40 μm or less. The maximum thickness of the electrode 4 is more preferably 30 μm or less, and even more preferably 20 μm or less. If the maximum thickness of the electrode 4 is 40 μm or less, deformation of the conductive linear body 21 tends to be small when the conductive linear body 21 and the electrode 4 are brought into contact, and conductivity tends to be more stable. The maximum thickness of the electrode 4 is preferably 5 μm or more, more preferably 8 μm or more, and even more preferably 10 μm or more.

In a plan view of the wiring sheet 100, the maximum width of the electrode 4 is preferably 1 mm or more and 10 mm or less. The maximum width of one of the electrodes 4 is preferably within the above range. The maximum width of the electrode 4 is more preferably 1.5 mm or more, and even more preferably 2 mm or more. The maximum width of the electrode 4 is more preferably 8 mm or less, even more preferably 6 mm or less, and even more preferably 4 mm or less. In a plan view of the wiring sheet 100, if the maximum width of the electrode 4 is 1 mm or more and 10 mm or less, it is easier to ensure contact points with the conductive linear members 21.

The electrode 4 can be formed using known electrode materials. Examples of electrode materials include conductive paste, metal foil, and metal wire.

Conductive pastes include silver paste, copper paste, and carbon paste. Of these, silver paste is preferred as the conductive paste from the standpoint of low volume resistivity.

When the electrode material is a metal foil or metal wire, examples of the metal of 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 steels such as stainless steel and carbon steel, brass, phosphor bronze, zirconium-copper alloys, beryllium copper, iron-nickel, nichrome, nickel-titanium, Kanthal, Hastelloy, and rhenium-tungsten. The metal foil or metal wire may also be plated with gold, tin, zinc, silver, nickel, chromium, nickel-chromium alloys, solder, or the like. When the electrode material is a metal wire, the metal wire may be one or two or more.

The electrode 4 is preferably gold-plated. This gold plating process can suppress migration of the electrode 4.

(Use of wiring sheet, etc.)
The wiring sheet 100 according to the present embodiment can be suitably used, for example, as a sheet heater. In this case, examples of uses of the sheet heater include a window defogger and a defroster. In addition to use as a sheet heater, the wiring sheet 100 can also be used as a flat cable for wiring electrical signals. The wiring sheet 100 according to the present embodiment can also be used as a heater for an optical sensor. In this case, the heater for the optical sensor can be used, for example, as a heater for an optical sensor such as a LiDAR sensor.

The resistance change rate when the wiring sheet 100 is used or stored in a humid and hot environment at a temperature of 85°C and a relative humidity of 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 when the wiring sheet 100 is used or stored in a humid and hot environment at a temperature of 85°C and a relative humidity of 85% RH is preferably 0% or close to 0%. The resistance change rate when the wiring sheet 100 is used or stored in a humid and hot environment may be 0% or more, or even 0.1% or more. A resistance change rate of 20% or less suppresses corrosion of the wiring sheet even when the wiring sheet is used or stored in a humid and hot environment. Furthermore, the wiring sheet can be used or stored in a humid and hot environment. The resistance change rate can be measured by the method described in the Examples below. Here, the time period when the wiring sheet 100 is used or stored in the above-mentioned humid and hot environment is 1,000 hours. The above-mentioned rate of change in resistance value may be below 0%. Furthermore, the rate of change in resistance value is preferably 0% or more and 20% or less, in terms of the absolute value of the rate of change in resistance value before and after use or storage of the wiring sheet 100 in a humid and hot environment at a temperature of 85°C and a relative humidity of 85% RH.

[Method of manufacturing wiring sheet]
Next, a method for manufacturing the wiring sheet 100 according to the present embodiment will be described. The method for manufacturing the wiring sheet 100 according to the present embodiment is not particularly limited. The method for manufacturing the wiring sheet 100 according to the present embodiment is one example of a method capable of producing the above-described wiring sheet 100. The wiring sheet 100 can be manufactured, for example, by the following steps.

First, a process for producing a wiring sheet including wiring body 2 is performed. In this process, a resin layer 3 is formed on a release sheet. If the resin layer 3 is formed from a thermosetting adhesive, the thermosetting adhesive for forming the resin layer 3 is applied to form a coating film. Next, the coating film is dried to produce an adhesive layer as the resin layer 3. Next, conductive linear bodies 21 are arranged and placed on the adhesive layer to form the wiring body 2. For example, with the adhesive layer with a release sheet placed on the outer surface of a drum member, the drum member is rotated and the conductive linear bodies 21 are spirally wound around the adhesive layer. Then, the bundle of spirally wound conductive linear bodies 21 is cut along the axial direction of the drum member. This forms the wiring body 2, which is then placed on the adhesive layer. In this way, a wiring body sheet is obtained in which wiring body 2 is formed on an adhesive layer with a release sheet. With this method, for example, by rotating the drum member and moving the payout portion of the conductive linear member 21 in a direction parallel to the axis of the drum member, it is easy to adjust the spacing L between adjacent conductive linear members 21 in the wiring body 2.

Next, a process is performed to provide a pair of electrodes 4 on the substrate 1. In this process, for example, a conductive paste or the like is printed in a predetermined arrangement on the substrate 1, and then dried, etc., to provide the pair of electrodes 4.

Next, the wiring sheet prepared above is placed on the substrate 1 provided with a pair of electrodes 4, and the thermosetting adhesive is cured. In this process, the wiring sheet is attached to the substrate 1 provided with a pair of electrodes 4 so that the pair of electrodes 4 contact both ends of the conductive linear members 21 in the wiring 2 of the wiring sheet. After the release sheet is removed, the thermosetting adhesive is subjected to a specified heat treatment to form a resin layer 3, and the wiring sheet 100 is produced.

[Effects of the embodiment]
According to this embodiment, the following effects can be achieved.
(1) According to this embodiment, even when used or stored in a humid and hot environment (for example, an environment at a temperature of 85° C. and a relative humidity of 85% RH), changes in the resistance value of wiring sheet 100 can be suppressed.
(2) According to this embodiment, the conductive linear body 21 can be blackened by setting the infrared reflectance at a wavelength of 1000 nm of the conductive linear body 21 to a range of 0% to 90%. This makes it possible to impart design features to the wiring sheet 100, for example. Furthermore, the wiring sheet 100 can be used as a heater for an optical sensor, for example.
(3) According to this embodiment, the resin layer 3 can fix the conductive linear body 21, suppress deformation in the thickness direction inside the wiring sheet 100, stabilize the contact between the conductive linear body 21 and the electrode 4, and stabilize the resistance value of the wiring body 2.

[Modification of the embodiment]
The present invention is not limited to the above-described embodiment, and includes modifications and improvements within the scope of achieving the object of the present invention.
For example, in the above-described embodiment, interconnect sheet 100 includes substrate 1, but is not limited to this. For example, interconnect sheet 100 does not have to include substrate 1. In such a case, interconnect sheet 100 can be used by being attached to an adherend by resin layer 3.
In the above-described embodiment, the resin layer 3 is disposed on the surface of the wiring sheet 100, but this is not limiting. For example, a protective sheet (not shown) may be provided on the resin layer 3 of the wiring sheet 100 to protect the wiring body 2.

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.
The wiring sheets obtained in the examples were evaluated as follows.

[Reflectance evaluation]
A tungsten plate having the same composition as the wire used in each Example and Comparative Example was plated with silver sulfide, palladium, copper oxide-palladium, or gold, each having the same composition as the plating layer used in each Example and Comparative Example 2, or a carbon coating having the same composition as the coating layer used in Comparative Example 1, to form a plating layer or coating layer of the respective material on the tungsten plate. The plating layer or coating layer was formed in the same manner as the plated tungsten wire or carbon-coated tungsten wire used in each Example and Comparative Example. For a tungsten plate having a silver sulfide-plated layer, a tungsten plate having a palladium-plated layer, a tungsten plate having a copper oxide-palladium-plated layer, a tungsten plate having a gold-plated layer, or a tungsten plate having a carbon-coated layer, the infrared reflectance of each of the plating layers or coating layers was measured at a wavelength of 1000 nm using an ultraviolet-visible-near-infrared spectrophotometer (manufactured by Shimadzu Corporation, product name "UV-VIS-NIR SPECTROPHOTOMETER UV-3600").

[Resistance value evaluation]
A resistance meter (manufactured by Hioki E.E. Corporation, product name "RM3545") was connected to the electrodes, and the resistance value ( _R1 ) of the wiring sheet was measured. After the wiring sheet was left to stand for 1000 hours in a humid and hot environment at a temperature of 85°C and a relative humidity of 85% RH, a resistance meter was connected to the electrodes, and the resistance value ( _R2 ) of the wiring sheet was measured. Then, the rate of change in resistance between _R1 and _R2 (unit: %) was calculated using the following formula (F2). The smaller this rate of change in resistance, the more suppressed the change in resistance of the wiring sheet.
Resistance change rate=[(R ₂ −R ₁ )/R ₁ ]×100(%) (F2)

[Appearance evaluation]
The wiring sheets obtained in each example and comparative example were placed on a black board and visually inspected. In Table 1, cases in which the conductive linear bodies were not visible and the design was excellent were indicated by "A," and cases in which the conductive linear bodies were visible and the design was poor were indicated by "F."

[Preparation Example 1]
(Preparation of curable adhesive)
A curable adhesive was obtained by blending 100 parts by mass of phenoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "YX7200B35") with 170 parts by mass of a polyfunctional hydrogenated bisphenol A diglycidyl ether epoxy compound (manufactured by Mitsubishi Chemical Corporation, product name "YX8000"), 0.2 parts by mass of 8-glycidoxyoctyltrimethoxysilane as a silane coupling agent, and 2 parts by mass of benzyl(4-hydroxyphenyl)methylsulfonium tetrakis(pentafluorophenyl)borate and 2 parts by mass of (4-hydroxyphenyl)methyl(4-methylbenzyl)sulfonium tetrakis(pentafluorophenyl)borate as thermal cationic polymerization initiators.

[Preparation Example 2]
(Preparation of (meth)acrylic acid ester polymer (A))
A (meth)acrylic acid ester polymer (A) was prepared by copolymerizing 55 parts by mass of 2-ethylhexyl acrylate, 5 parts by mass of 4-acryloylmorpholine, 15 parts by mass of isobornyl acrylate, and 25 parts by mass of 2-hydroxyethyl acrylate by solution polymerization. The molecular weight of this (meth)acrylic acid ester polymer (A) was measured by the method described above, and the weight average molecular weight (Mw) was 600,000. The glass transition temperature (Tg; °C) of this (meth)acrylic acid ester polymer (A) was calculated using the FOX equation based on the glass transition temperatures (Tg) of the respective monomers constituting the (meth)acrylic acid ester polymer (A) as homopolymers, and was found to be -36.5 °C.

[Preparation Example 3]
(Preparation of adhesive composition)
100 parts by mass of the (meth)acrylic acid ester polymer (A) obtained in the above process, 0.18 parts by mass of trimethylolpropane-modified tolylene diisocyanate as the crosslinking agent (B), 7 parts by mass of ε-caprolactone-modified tris-(2-acryloxyethyl)isocyanurate as the active energy ray-curable component (C), 0.7 parts by mass of a mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone in a 1:1 mass ratio as the photopolymerization initiator (D), and 0.28 parts by mass of 3-glycidoxypropyltrimethoxysilane as the silane coupling agent were mixed, thoroughly stirred, and diluted with methyl ethyl ketone to obtain a coating solution of a pressure-sensitive adhesive composition.

[Example 1]
(Preparation of silver sulfide-plated tungsten wire)
A sulfurizing solution was prepared by adding 3.5 g of potassium sulfide to 1 L of water. A silver-plated tungsten wire (diameter 12 μm, volume resistivity 5.5×10 ⁻⁸ Ω·m) was immersed in the sulfurizing solution to prepare a silver sulfide-plated tungsten wire. The thickness of the silver sulfide plating layer on the prepared silver sulfide-plated tungsten wire was 0.1 μm. The silver sulfide-plated tungsten wire had a hue close to black.

(Production of wiring sheet)
The curable adhesive obtained in Preparation Example 1 was applied to a thickness of 10 μm on a 38 μm thick release sheet (manufactured by Lintec Corporation, product name "SP-PET382150") and cut into a 250 mm x 320 mm rectangle to produce an adhesive sheet with a curable adhesive layer (hereinafter sometimes referred to as the adhesive layer). The silver sulfide-plated tungsten wire (hereinafter sometimes referred to as the wire) produced above was prepared as the conductive linear body. Next, the adhesive sheet obtained above was wrapped around a drum member with a rubber outer periphery, with the surface of the adhesive layer facing outward and without wrinkles, and both ends of the adhesive sheet in the circumferential direction were fixed with double-sided tape. The wire wound around the bobbin was attached to the surface of the adhesive layer of the adhesive sheet located near the end of the drum member, and the wire was then unwound and wound around the drum member. The drum member was gradually moved in a direction parallel to the drum axis so that the wire was wound around the drum member in a spiral at equal intervals of 3 mm. This resulted in a wiring body with 96 wires arranged on the surface of the adhesive layer. The wires were then cut, and the wiring body was removed from the drum member. The wiring body was cut into a 40 mm x 82 mm width so that 12 wires could be removed, and a wiring body sheet was produced. The overall resistance value r in the axial direction of the conductive linear body was 4.93 Ω.

(Preparation of substrate with electrode)
A silver paste (manufactured by Jujo Chemical Co., Ltd., product name "#2 TF Silver Paste") was screen-printed onto a 2 mm thick glass substrate with a width of 3 mm and an inter-electrode distance of 7.8 mm. The resulting substrate was then dried at 150 °C for 30 minutes to form a coating film with a thickness of 12 μm, producing a substrate with electrodes. Subsequently, a nickel layer (thickness: 1 μm) and a gold layer (thickness: 50 nm) were laminated in this order on the silver paste by electroless plating, producing a substrate with electrodes (resistance value R: 0.56 Ω). The elastic modulus of the electrode was 62.6 GPa.

(Preparation of composition for forming coating layer)
A visible light-absorbing infrared transparent ink (manufactured by Jujo Chemical Co., Ltd., product name "TG-IR Ink PB-A Black") was prepared as the infrared transparent ink. This infrared transparent ink contains a perylene-based pigment. 2 parts by mass of 3-aminopropyltrimethoxysilane and 5 parts by mass of trimethylolpropane adduct xylylene diisocyanate were blended with 100 parts by mass of this infrared transparent ink to obtain a coating layer-forming composition.

(Preparation of substrate with coating layer)
The coating layer-forming composition prepared above was screen printed on the surface opposite to the electrode-provided surface of the electrode-equipped substrate to form a coating film. The coating film was then dried under two-stage drying conditions: 10 minutes at 90 ° C., followed by 30 minutes at 150 ° C., to form a coating layer with a thickness of 6 μm on the substrate. The coating layer formed from the coating layer-forming composition was colored black, and had a maximum transmittance of 89% and a minimum of 86% for near-infrared light with a wavelength of 905 nm to 1000 nm, and a maximum transmittance of 5% and a minimum of 0% for visible light with a wavelength of 380 nm to 700 nm. The refractive index of near-infrared light with a wavelength of 905 nm was 2.10.

(Fabrication of wiring sheet)
The wiring sheet prepared above was attached to the substrate with electrodes so that the electrodes were located at both ends of the wires, and then heated at a temperature of 120°C under a pressure of 0.5 MPa for 30 minutes to obtain the wiring sheet of Example 1.

(Preparation of protective sheet)
The pressure-sensitive adhesive composition obtained in Preparation Example 3 was applied to a thickness of 100 μm on a 100 μm cycloolefin polymer film (manufactured by Zeon Corporation, product name "ZF16") and cut into a 50 mm × 120 mm rectangle. A circle with a diameter of 5 mm was then cut out so that the center-to-center distance between the two circles was 7.8 mm, to prepare a protective sheet.

(Production of wiring sheet with protective sheet)
The protective sheet was attached to the wiring sheet so that the electrodes of the wiring sheet and the circles of the protective sheet were aligned. Then, ultraviolet light with a wavelength of 365 nm was irradiated at an illuminance of 200 mW/cm ² and a light quantity of 1000 mJ/cm ² to obtain a wiring sheet with the protective sheet.

[Example 2]
A wiring sheet with a protective sheet was produced in the same manner as in Example 1, except that palladium-plated tungsten wire (diameter 12 μm, volume resistivity 5.5×10 ⁻⁸ Ω·m) was used as the conductive linear body instead of the silver sulfide-plated tungsten wire. The palladium-plated tungsten wire has a hue close to black.

[Example 3]
A wiring sheet with a protective sheet was produced in the same manner as in Example 1, except that copper oxide-palladium-plated tungsten wire was used as the conductive linear body instead of the silver sulfide-plated tungsten wire. The copper oxide-palladium-plated tungsten wire has a hue close to black. The copper oxide-palladium-plated tungsten wire was produced as follows.

A copper-plated tungsten wire (diameter 12 μm, volume resistivity 4.23×10 ⁻⁸ Ω·m) was immersed in a plating solution containing palladium ("OPC Black Copper", manufactured by Okuno Chemical Industries Co., Ltd.), and then treated with an anti-tarnish agent ("OPC Black Keep", manufactured by Okuno Chemical Industries Co., Ltd.) to produce a copper oxide-palladium-plated tungsten wire. The copper oxide-palladium-plated tungsten wire has a plating layer containing a mixture of copper oxide and palladium on the tungsten wire. The thickness of the copper oxide-palladium plating layer on the produced copper oxide-palladium-plated tungsten wire was 0.2 μm.

[Comparative Example 1]
A wiring sheet with a protective sheet was produced in the same manner as in Example 1, except that a carbon-coated tungsten wire (diameter 12 μm, volume resistivity 5.5×10 ⁻⁸ Ω·m) was used as the conductive linear body instead of the silver sulfide-plated tungsten wire. The carbon-coated tungsten wire has a hue close to black.

[Comparative Example 2]
A wiring sheet with a protective sheet was produced in the same manner as in Example 1, except that gold-plated tungsten wire (diameter 12 μm, volume resistivity 5.5×10 ⁻⁸ Ω·m) was used as the conductive linear body instead of the silver sulfide-plated tungsten wire. The gold-plated tungsten wire does not have a hue close to black.

The wiring sheets obtained in each example demonstrated better results in both reflectance evaluation and resistance evaluation compared to the wiring sheets obtained in each comparative example. Furthermore, each example with a low rate of change in resistance and low infrared reflectance also demonstrated good appearance evaluation and excellent design.

Figure 3 shows a graph showing the relationship between time and the rate of change in resistance when the wiring sheet is left in an environment at a temperature of 85°C and a relative humidity of 85% RH. In Figure 3, the horizontal axis represents the time of leaving, and the vertical axis represents the rate of change in resistance. In Figure 3, E represents the wiring sheet produced in Example 1, and C represents the wiring sheet produced in Comparative Example 1. As shown in Figure 3, the wiring sheet produced in Example 1 shows a larger rate of change in resistance over time than the wiring sheet produced in Comparative Example 1.

These results confirm that the wiring sheet according to this embodiment can suppress corrosion in a humid and hot environment while achieving blackening of the conductive linear body.

1...substrate, 2...wiring body, 21...conductive linear body, 3...resin layer, 4...electrode, 100...wiring sheet.

Claims (8)

a wiring body including a conductive linear body;
a pair of electrodes in direct contact with the conductive linear body;
Equipped with
the conductive linear body has an infrared reflectance of 0% or more and 90% or less at a wavelength of 1000 nm;
The rate of change in resistance value after leaving the capacitor for 1000 hours in a humid and hot environment at a temperature of 85°C and a relative humidity of 85% RH is 50% or less.
Wiring sheet. The wiring sheet according to claim 1 ,
a relationship between a resistance value R of the electrode in the axial direction and a total resistance value r of the conductive linear body in the axial direction satisfies the condition expressed by the following formula (F1):
Wiring sheet.
r>R...(F1) The wiring sheet according to claim 1 or 2,
Further, a resin layer is provided to directly or indirectly support the wiring body.
Wiring sheet. The wiring sheet according to claim 1 or 2,
The maximum width of the electrode is 1 mm or more and 10 mm or less.
Wiring sheet. The wiring sheet according to claim 1 or 2,
The wiring body has a structure in which the conductive linear bodies are arranged at intervals.
Wiring sheet. The wiring sheet according to claim 1 or 2,
The wiring body is composed of only one of the conductive linear bodies.
Wiring sheet. The wiring sheet according to claim 1 or 2,
The conductive linear body is coated with sulfide or palladium.
Wiring sheet. The wiring sheet according to claim 1 or 2,
The conductive linear body is coated with silver sulfide.
Wiring sheet.