JP7820177B2 - Method for manufacturing a conductive structure - Google Patents

Description

The present invention relates to a method for manufacturing a conductive structure.

A sheet-shaped conductive member has been proposed, comprising multiple conductive linear elements arranged at intervals. This sheet-shaped conductive member could potentially be used as a component for a variety of products, such as heating elements for heating devices, heat-generating textile materials, and protective films for displays.

For example, Patent Document 1 describes a sheet having a plurality of linear bodies extending in one direction, the plurality of linear bodies having a volume resistivity R of 1.0×10 ⁻⁷ Ωcm or more and 1.0×10 ⁻¹ Ωcm or less. The sheet described in Patent Document 1 has a plurality of linear bodies arranged parallel to one another at intervals. The relationship between the diameter D of the linear bodies and the spacing L between adjacent linear bodies satisfies Formula A (Formula A: L/D≧3), and the relationship between the diameter D of the linear bodies, the spacing L between adjacent linear bodies, and the volume resistivity R of the linear bodies satisfies Formula B (Formula B: (D ² /R)×(1/L)≧0.003). The units of D and L in the formulas are cm.

International Publication No. 2017/086395

A sheet-like conductive member may comprise, for example, a plurality of conductive linear members arranged at intervals, a resin layer for supporting the conductive linear members, and a substrate, with the resin layer being disposed on the surface of the sheet-like conductive member. Such sheet-like conductive members are sometimes used by attaching the resin layer of the sheet-like conductive member to an object to which it is to be attached. When attaching a sheet-like conductive member to an object, for example, if the sheet-like conductive member comprises a substrate, the entire sheet-like conductive member becomes thick, which can result in poor conformability to the object.

The object of the present invention is to provide a method for manufacturing a conductive structure that improves conformability to an object when a sheet-like conductive member comprising a conductive linear body and a resin layer is attached to the object.

According to one aspect of the present invention, there is provided a method for manufacturing a conductive structure comprising an object and a sheet-like conductive member provided in contact with the object, wherein the sheet-like conductive member comprises a plurality of conductive linear members arranged at intervals and a resin layer supporting the plurality of conductive linear members, the plurality of conductive linear members being arranged in contact with the resin layer, and the resin layer constituting at least a portion of a first surface of the sheet-like conductive member and at least a portion of a second surface of the sheet-like conductive member. The manufacturing method includes the following steps: a laminate preparation step of preparing a laminate comprising the sheet-like conductive member, a first release sheet provided in contact with the first surface of the sheet-like conductive member, and a second release sheet provided in contact with the second surface opposite the first surface; a first exposure step of peeling the first release sheet from the laminate to expose the first surface; an attachment step of bonding the exposed first surface to the surface of the object; and a second exposure step of peeling the second release sheet that was not peeled in the first exposure step to expose the second surface that was not exposed.

In the method for manufacturing a conductive structure according to one aspect of the present invention, it is preferable that the resin layer is a curable resin layer, and that after the adhering step, a curing step is further provided in which the curable resin layer that has been attached to the object is cured.

In one aspect of the present invention, the method for manufacturing a conductive structure further includes, after the second exposure step, a protective layer formation step of providing a protective layer on the exposed second surface, and it is preferable that the protective layer be the outermost layer.

In one aspect of the method for manufacturing a conductive structure according to the present invention, it is preferable that, after the second exposure step, an electrode placement step be further provided in which a pair of electrodes is placed on the exposed second surface so as to be electrically connected to the conductive linear body.

In the method for manufacturing a conductive structure according to one aspect of the present invention, it is preferable that the surface to be bonded to the first surface of the object is a three-dimensional structure having a three-dimensional shape.

In the method for manufacturing a conductive structure according to one aspect of the present invention, the bonding step preferably involves bonding the first surface exposed in the first exposing step to the surface of the object by vacuum-pressure forming (TOM forming).

In the method for manufacturing a conductive structure according to one aspect of the present invention, it is preferable that the conductive linear element has a wave shape when viewed in a plan view of the sheet-like conductive member.

In the method for manufacturing a conductive structure according to one aspect of the present invention, it is preferable that the second release sheet comprises a release substrate and a release agent layer provided on at least one surface of the release substrate, and that the release substrate is a polypropylene film.

The present invention provides a method for manufacturing a conductive structure that improves conformability to an object when a sheet-shaped conductive member comprising a conductive linear body and a resin layer is attached to the object.

FIG. 1 is a schematic perspective view showing an example of a laminate applied to the method for manufacturing a conductive structure according to the first, third, and fourth embodiments. FIG. 2 is a cross-sectional view showing the II-II cross section of FIG. 1A to 1C are schematic views for explaining a method for manufacturing a conductive structure according to a first embodiment. FIG. 10 is a schematic perspective view showing an example of a laminate applied to a method for manufacturing a conductive structure according to a second embodiment. 5A to 5C are schematic views for explaining a method for manufacturing a conductive structure according to a second embodiment. 10A to 10C are schematic views for explaining a method for manufacturing a conductive structure according to a third embodiment. 10A to 10C are schematic views for explaining a method for manufacturing a conductive structure according to a fourth embodiment. FIG. 10 is a schematic perspective view of a conductive structure obtained by a manufacturing method according to a fourth embodiment. FIG. 10 is a schematic perspective view showing an example of a laminate applied to a method for manufacturing a conductive structure according to a modified embodiment. FIG. 10 is a cross-sectional view showing the XX cross section of FIG. 9. 10A to 10C are schematic diagrams illustrating a method for manufacturing a conductive structure according to a modified embodiment.

The following describes a method for manufacturing a conductive structure according to preferred embodiments of the present invention, taking each embodiment as an example. The present invention is not limited to the contents of the following embodiments.

[First embodiment]
A first embodiment of the present invention will be described with reference to the drawings. Note that in the drawings, some parts are shown enlarged or reduced in size for ease of explanation.

As shown in Figures 1 to 3, the first embodiment is a method for manufacturing a conductive structure 320 including an object 90 and a sheet-like conductive member 12 provided in contact with the object 90. Figures 3(A) to 3(D) are schematic diagrams for explaining the method for manufacturing the conductive structure 320 according to the first embodiment, showing an overview of each step.

As shown in Figures 1 and 2, the sheet-like conductive member 12 comprises a plurality of conductive linear members 13 arranged at intervals, and a resin layer 15 that supports the plurality of conductive linear members 13. The plurality of conductive linear members 13 are arranged in contact with the resin layer 15. The resin layer 15 constitutes at least a portion of the first surface 12A of the sheet-like conductive member 12 and at least a portion of the second surface 12B of the sheet-like conductive member 12.

The manufacturing method for the conductive structure 320 according to this embodiment includes a laminate preparation process, a first exposure process, an attachment process, and a second exposure process, as described below.

The laminate preparation process is a process for preparing a laminate 120 comprising a sheet-like conductive member 12, a first release sheet 18 provided in contact with the first surface 12A of the sheet-like conductive member 12, and a second release sheet 19 provided in contact with the second surface 12B opposite the first surface 12A.

The first exposure step is a step of peeling the first release sheet 18 from the laminate 120 to expose the first surface 12A. In this embodiment, as shown in FIG. 3(A), the first release sheet 18 is peeled from the laminate 120, and as shown in FIG. 3(B), the first surface 12A of the sheet-like conductive member 12 is exposed.

The bonding process is a process of bonding the exposed first surface 12A to the surface of the object 90. In this embodiment, as shown in Figure 3 (C), the exposed first surface 12A of the sheet-like conductive member 12 is bonded to the surface of the object 90.

The second exposure step is a step in which the second release sheet 19 that was not peeled off in the first exposure step is peeled off to expose the second surface 12B that was not exposed in the first exposure step. In this embodiment, as shown in Figure 3(D), the second release sheet 19 that was not peeled off in the first exposure step is peeled off, exposing the second surface 12B that was not exposed in the first exposure step.

<Laminate preparation step>
1, 2, and 3(A), in the laminate preparation step, a laminate 120 is prepared. The laminate 120 specifically includes a first release sheet 18, a sheet-like conductive member 12 provided on the first release sheet 18 and having a plurality of conductive linear members 13 and a resin layer 15, and a second release sheet 19 provided on the sheet-like conductive member 12. The sheet-like conductive member 12 is sandwiched between the first release sheet 18 and the second release sheet 19. The first release sheet 18 faces the resin layer 15 that constitutes the first surface 12A of the sheet-like conductive member 12. The second release sheet 19 faces the plurality of conductive linear members 13 and the resin layer 15 that constitute the second surface 12B of the sheet-like conductive member 12. The first release sheet 18 is provided in direct contact with the resin layer 15 of the sheet-like conductive member 12, and the second release sheet 19 is provided in direct contact with the plurality of conductive linear bodies 13 of the sheet-like conductive member 12. In this embodiment, the plurality of conductive linear bodies 13 are arranged so that a portion of their circumferential surfaces is exposed from the second surface 12B.

In the sheet-like conductive member 12, multiple conductive linear bodies 13 are arranged with intervals between them. Each of the multiple conductive linear bodies 13 is substantially linear in a plan view of the sheet-like conductive member 12. Furthermore, the cross sections of the multiple conductive linear bodies 13 are nearly circular. The multiple conductive linear bodies 13 are arranged in a direction intersecting the direction in which the conductive linear bodies 13 extend (i.e., the axial direction of the conductive linear bodies 13). A portion of the circumferential surface of each of the conductive linear bodies 13 is in contact with the resin layer 15, and a portion of the circumferential surface of each of the multiple conductive linear bodies 13 is exposed to the resin layer 15. Therefore, in the sheet-like conductive member 12, the resin layer 15 constitutes the first surface 12A of the sheet-like conductive member 12. Furthermore, in the sheet-like conductive member 12, the resin layer 15 constitutes a portion of the second surface 12B of the sheet-like conductive member 12. In other words, the second surface 12B of the sheet-shaped conductive member 12 is composed of a resin layer 15 and multiple conductive linear members 13.

The laminate 120 can be fabricated, for example, by the following procedure 1. First, a resin composition for forming the resin layer 15 is applied to the first release sheet 18 to form a coating. Next, the coating is dried to form the resin layer 15. Next, the conductive linear bodies 13 are arranged on the resin layer 15. For example, with the resin layer 15 with the first release sheet 18 attached thereto placed on the outer circumferential surface of a drum member, the drum member is rotated, and the conductive linear bodies 13 are spirally wound around the resin layer 15. Then, the bundle of spirally wound conductive linear bodies 13 is cut along the axial direction of the drum member. As a result, multiple conductive linear bodies 13 arranged at intervals from one another are arranged on the resin layer 15. In this embodiment, portions of the circumferential surfaces of the multiple conductive linear bodies 13 are embedded in the resin layer 15, and portions of the circumferential surfaces are exposed from the resin layer 15. Then, the second release sheet 19 is placed on the resin layer 15. That is, a second release sheet 19 is placed on the surface of the resin layer 15 opposite to the surface in contact with the first release sheet 18. Next, the resin layer 15, which includes the first release sheet 18 and the second release sheet 19 and on which the multiple conductive linear members 13 are arranged, is removed from the drum member. By performing the above step 1, a laminate 120 is obtained.

The laminate 120 can also be produced, for example, by the following procedure 2. First, a resin composition for forming the resin layer 15 is applied onto release sheet A to form a coating film. Next, the coating film is dried to produce the resin layer 15. Next, release sheet B is placed on the surface of the resin layer 15 opposite the surface to which release sheet A is in contact. After release sheet B is placed, it is wound into a roll to produce a take-up roll. Next, the take-up roll is unwound, and while peeling off either release sheet A or release sheet B, the conductive linear body 13 is placed on the resin layer 15. The conductive linear body 13 may be placed in the same manner as in procedure 1 above. After the conductive linear body 13 is placed, a release sheet C of the same type as or a different type from the peeled release sheet is placed on the surface from which the release sheet was peeled. Release sheets A, B, and C are selected in a combination that ultimately results in a laminate 120 having a structure in which the first release sheet 18, the resin layer 15 on which the plurality of conductive linear bodies 13 are spaced apart, and the second release sheet 19 are laminated in this order. The release sheet (i.e., release sheet A or release sheet B) that was peeled immediately before placing the conductive linear bodies 13 on the resin layer 15 may be reused as release sheet C, which will be placed after the conductive linear bodies 13 are placed. For example, if release sheet B is the release sheet that is peeled immediately before placing the conductive linear bodies 13 on the resin layer 15, the first release sheet 18 is release sheet A, and the second release sheet 19 may be a new release sheet B different from the previously removed release sheet B, or the previously removed release sheet B may be reused. Alternatively, either release sheet A or a different release sheet C may be used as the second release sheet. The laminate 120 can also be obtained by the above procedure 2.

With these methods, for example, by rotating the drum member and moving the payout portion of the conductive linear body 13 in a direction parallel to the axis of the drum member, it becomes easy to adjust the distance L between adjacent conductive linear bodies 13 arranged at intervals on the resin layer 15.

Next, we will explain the materials that make up the laminate 120 prepared in the laminate preparation process.

(Conductive linear body)
The volume resistivity of the conductive linear bodies 13 is, for example, preferably 1.0×10 ⁻⁹ Ω·m or more and 1.0×10 ⁻³ Ω·m or less, and more preferably 1.0×10 ⁻⁸ Ω·m or more and 1.0×10 ⁻⁴ Ω·m or less. When the volume resistivity of the conductive linear bodies 13 is in the above range, it becomes easier to reduce the surface resistance of the plurality of conductive linear bodies 13 as a whole.
The volume resistivity of the conductive linear body 13 was measured as follows: Silver paste was applied to one end of the conductive linear body 13 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 to determine the resistance value of the conductive linear body 13. The volume resistivity of the conductive linear body 13 was then calculated by multiplying the resistance value by the cross-sectional area (unit: ^m2 ) of the conductive linear body 13 and dividing the obtained value by the measured length (0.04 m).

The cross-sectional shape of the conductive linear body 13 is not particularly limited. The cross-sectional shape of the conductive linear body 13 is not limited to a circular shape, and can be, for example, a polygonal shape, a flat shape, an elliptical shape, or the like. From the standpoint of compatibility with the resin layer 15, etc., it is preferable that the cross-sectional shape of the conductive linear body 13 be an elliptical shape or a circular shape.

When the cross section of the conductive linear body 13 is circular, the diameter D (see FIG. 2 ) of the conductive linear body 13 is preferably 1 μm or more and 125 μm or less. From the viewpoints of suppressing an increase in sheet resistance and improving heat generation efficiency and dielectric breakdown resistance when the sheet-like conductive member 12 is used as a heating element in the conductive structure 320, the diameter D of the conductive linear body 13 is more preferably 5 μm or more and 75 μm or less, even more preferably 8 μm or more and 60 μm or less, and even more preferably 12 μm or more and 40 μm or less.
When the cross section of the conductive linear body 13 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 13 is determined by observing the conductive linear body 13 using a digital microscope, measuring the diameter of the conductive linear body 13 at five randomly selected locations, and averaging the measured values.

The interval L (see FIG. 2) between the conductive linear members 13 is preferably 0.3 mm or more and 50 mm or less, more preferably 0.5 mm or more and 30 mm or less, and even more preferably 0.8 mm or more and 20 mm or less.
If the spacing between the conductive linear bodies 13 is within the above range, the conductive linear bodies 13 are relatively densely packed, thereby maintaining a low resistance of the conductive linear bodies 13 and improving the functionality of the sheet-like conductive member 12, such as by making the distribution of temperature rise uniform when the sheet-like conductive member 12 is used as a heating element for the conductive structure 320.

The distance L between the conductive linear members 13 is measured by observing the conductive linear members 13 using a digital microscope and measuring the distance between two adjacent conductive linear members 13 .
The interval between two adjacent conductive linear bodies 13 is the length along the direction in which the conductive linear bodies 13 are arranged, and is the length between opposing portions of the two conductive linear bodies 13 (see FIG. 2 ). When the conductive linear bodies 13 are arranged at uneven intervals, the interval L is the average value of the intervals between all adjacent conductive linear bodies 13.

The conductive linear body 13 is not particularly limited, and may be 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, easy handling, and versatility. When the sheet-like conductive member 12 is used as a heating element of the conductive structure 320, the resistance of the metal wire linear body can be significantly reduced, and even if the diameter of the metal wire linear body is extremely small, it can still pass a current required for heat generation. This makes the conductive linear body 13 less visible. In other words, when a metal wire linear body is used as the conductive linear body 13, the total resistance value of the multiple conductive linear bodies 13, calculated as the total resistance value in the axial direction of the conductive linear body 13, is reduced, while light transmittance is easily improved. Furthermore, when the sheet-like conductive member 12 is used as a heating element of the conductive structure 320, rapid heat generation is easily achieved. Furthermore, as described above, a linear body with a small diameter is easily obtained.
In addition to a metal wire linear body, examples of the conductive linear body 13 include a linear body containing carbon nanotubes and a linear body in which a conductive coating is applied to a thread.

The metal wire linear body may be a linear body made of a single metal wire, or a linear body made of multiple 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 (e.g., 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). Metal wires may also be plated with gold, tin, zinc, silver, nickel, chromium, nickel-chromium alloys, or solder, or may be surface-coated with a carbon material or polymer, as described below. Wires containing one or more metals selected from tungsten, molybdenum, and alloys containing these metals are particularly preferred from the viewpoint of forming a thin, high-strength, and low-volume-resistivity conductive linear body 13.

The metal wire may be a metal wire coated with a carbon material. When the metal wire is coated with a carbon material, the metallic luster is reduced, making it easier to make the metal wire less noticeable. Furthermore, when the metal wire is coated with a carbon material, metal corrosion is also suppressed.
Examples of carbon materials that can be used to coat metal wires include amorphous carbon (e.g., carbon black, activated carbon, hard carbon, soft carbon, mesoporous carbon, and carbon fiber), graphite, fullerene, graphene, and carbon nanotubes.

Carbon nanotube-containing linear bodies can be obtained, for example, by drawing carbon nanotubes into a sheet from the end of a carbon nanotube forest (a growth structure in which multiple carbon nanotubes are grown on a substrate so that they are aligned perpendicular to the substrate; sometimes referred to as an "array"). The drawn carbon nanotube sheets are then bundled and twisted. In this production method, ribbon-shaped carbon nanotube linear bodies are obtained if no twist is applied during twisting, while thread-shaped carbon nanotubes are obtained if twist is applied. Ribbon-shaped carbon nanotube linear bodies are linear bodies in which the carbon nanotubes do not have a twisted structure. Carbon nanotube linear bodies can also be obtained by spinning a carbon nanotube dispersion. Carbon nanotube linear bodies can be produced by spinning, for example, using the method disclosed in U.S. Patent Application Publication No. 2013/0251619 (JP Patent Publication No. 2012-126635). From the viewpoint of obtaining uniformity in the diameter of the carbon nanotube linear bodies, it is desirable to use thread-like carbon nanotube linear bodies, and from the viewpoint of obtaining highly pure carbon nanotube linear bodies, it is preferable to obtain thread-like carbon nanotube linear bodies by twisting a carbon nanotube sheet. The carbon nanotube linear bodies may be linear bodies formed by weaving together two or more carbon nanotube linear bodies. Furthermore, the carbon nanotube linear bodies may be linear bodies formed by combining carbon nanotubes with other conductive materials (hereinafter also referred to as "composite linear bodies").

Examples of the composite linear body include (1) a composite linear body in which, in a process of obtaining a carbon nanotube linear body by drawing carbon nanotubes into a sheet form from the end of a carbon nanotube forest, bundling the drawn carbon nanotube sheet, and then twisting the carbon nanotube bundles, a metal element or a metal alloy is supported on the surface of the carbon nanotube forest, sheet, or bundle, or twisted linear body by vapor deposition, ion plating, sputtering, wet plating, or the like; (2) a composite linear body in which bundles of carbon nanotubes are twisted together with linear bodies of a metal element or a metal alloy, or a composite linear body; and (3) a composite linear body in which linear bodies of a metal element or a metal alloy, or a composite linear body, are braided with carbon nanotube linear bodies or composite linear bodies. In the composite linear body of (2), a metal may be supported on the carbon nanotubes when twisting the bundles of carbon nanotubes, as in the composite linear body of (1). Furthermore, the composite linear body of (3) is a composite linear body in which two linear bodies are braided together, but as long as it contains at least one linear body of a simple metal or a metal alloy, or a composite linear body, it may be a composite linear body in which three or more carbon nanotube linear bodies, or linear bodies of a simple metal or a metal alloy, or a composite linear body are braided together.
Examples of the metal for the composite linear body include simple metals such as gold, silver, copper, iron, aluminum, nickel, chromium, tin, and zinc, and alloys containing at least one of these simple metals (such as copper-nickel-phosphorus alloys and copper-iron-phosphorus-zinc alloys).

The conductive linear body 13 may be a linear body in the form of a thread coated with a conductive material. Examples of the thread include threads spun from resins such as nylon or polyester. Examples of the conductive coating include coatings of metals, conductive polymers, and carbon materials. The conductive coating can be formed by plating, vapor deposition, or other methods. A linear body in which a conductive coating is applied to a thread can improve the conductivity of the linear body while maintaining the flexibility of the thread. In other words, it becomes easier to reduce the resistance of the conductive linear body 13.

When the conductive structure 320 includes an electrode, it is preferable that the conductive linear body 13 be a gold-plated linear body in order to reduce the contact resistance between the conductive linear body 13 and the electrode. By gold-plating the conductive linear body 13, the effect of the contact resistance can be reduced to a negligible level, making the resistance value more stable.

(Resin layer)
The resin layer 15 is a layer containing resin. The resin layer 15 can directly or indirectly support the conductive linear body 13. The resin layer 15 is preferably a layer containing an adhesive. If the resin layer 15 is a layer containing an adhesive, the conductive linear body 13 can be easily attached to the resin layer 15 when multiple conductive linear body 13 are arranged at intervals relative to the resin layer 15. Furthermore, if the resin layer 15 is a layer containing an adhesive, the resin layer 15 constituting the first surface 12A of the sheet-like conductive member 12 and the object 90 can be easily attached. Note that the resin layer 15 preferably has elasticity. In such a case, the elasticity of the sheet-like conductive member 12 can be ensured.

When the resin layer 15 contains an adhesive, the adhesive used in the resin layer 15 is not particularly limited. Examples of adhesives that can be used include dry-solidifying adhesives, heat-melting adhesives, curing adhesives (curable adhesives), and pressure-sensitive adhesives. Dry-solidifying adhesives refer to adhesives that solidify by drying the adhesive composition after application to remove moisture or solvent. Curing adhesives refer to adhesives that solidify by applying an adhesive composition, optionally drying it, and then undergoing a chemical reaction. Curing adhesives include (1) adhesives that solidify by undergoing a chemical reaction such as polymerization through at least one of heat treatment and energy ray irradiation treatment, and (2) adhesives that solidify by reacting with moisture (water). Heat-melting adhesives refer to adhesives that melt with heat and bond by cooling. Pressure-sensitive adhesives refer to adhesives (adhesives) that bond by the adhesive properties of a pressure-sensitive adhesive (pressure-sensitive adhesive). Examples of adhesives for the resin layer 15 include adhesives that become adhesive when moistened.

The resin layer 15 may be a layer containing an adhesive (pressure-sensitive adhesive). The adhesive of the adhesive layer is not particularly limited. Examples of adhesives include acrylic adhesives, urethane adhesives, rubber adhesives, polyester adhesives, silicone adhesives, and polyvinyl ether adhesives. Among these, the adhesive is preferably at least one selected from the group consisting of acrylic adhesives, urethane adhesives, and rubber adhesives, and more preferably an acrylic adhesive.

Examples of acrylic adhesives include acrylic polymers containing structural units derived from alkyl (meth)acrylates having a straight-chain alkyl group or a branched-chain alkyl group (i.e., polymers obtained by polymerizing at least alkyl (meth)acrylates), and acrylic polymers containing structural units derived from (meth)acrylates having a cyclic structure (i.e., polymers obtained by polymerizing at least (meth)acrylates having a cyclic structure). Here, "(meth)acrylate" is used to refer to both "acrylate" and "methacrylate," and the same applies to other similar terms.

Acrylic polymers (including homopolymers and copolymers) may be crosslinked with a crosslinking agent. Examples of crosslinking agents include epoxy-based crosslinking agents, isocyanate-based crosslinking agents, aziridine-based crosslinking agents, and metal chelate-based crosslinking agents. When crosslinking an acrylic polymer, at least one of the following functional groups derived from the monomer components of the acrylic polymer, such as a hydroxyl group and a carboxyl group, which react with these crosslinking agents, can be introduced into the acrylic polymer.

The resin layer 15 is not particularly limited and may be, for example, curable or non-curable. For example, when the resin layer 15 contains an adhesive or a pressure-sensitive adhesive, the resin layer 15 may be curable or non-curable. The resin layer 15 is preferably a curable resin layer, since it can form the outermost layer of the conductive structure 320 (i.e., the conductive structure 320 can be used with the second surface 12B of the sheet-like conductive member 12 exposed). If the resin layer 15 is a curable resin layer, the surface of the resin layer 15 is likely to have excellent scratch resistance. Furthermore, from the perspective of ease of application, the resin layer 15 is more preferably an energy ray-curable resin layer. Examples of energy ray-curable resin layers include those curable with ultraviolet light, visible light, infrared light, and electron beams. Note that "energy ray curing" also includes thermal curing by heating using energy rays.

In this specification, "curing" does not simply refer to the reaction of a curable resin. The concept of curing can also include the suppression of tackiness (preferably the elimination of tackiness) on the surface of the cured resin layer 15, and the achievement of excellent scratch resistance on the surface of the cured resin layer 15.

Furthermore, when the resin layer 15 constitutes the outermost layer of the conductive structure 320, it is preferable that the resin layer 15 has little tackiness, and preferably has no tackiness. Furthermore, from this perspective, the resin layer 15 is preferably a curable resin, and more preferably a curable adhesive layer containing an energy ray-curable resin.

In this specification, tackiness refers to the sticky feeling that occurs on the surface of a substance. In this embodiment, tackiness refers to the sticky feeling that occurs on the surface of the resin layer 15.

When the resin layer 15 is an energy ray-curable resin layer, it may contain an energy ray-curable resin. For example, when the resin layer 15 is a layer containing an adhesive, the resin layer 15 is formed from an adhesive composition containing an energy ray-curable resin in addition to the adhesive. Furthermore, when the resin layer 15 is a layer containing an adhesive, the resin layer 15 is formed from an adhesive composition containing an energy ray-curable resin. Examples of energy ray-curable resins include compounds having at least one polymerizable double bond in the molecule. Preferably, the compound having at least one polymerizable double bond in the molecule is an acrylate compound having a (meth)acryloyl group. Examples of the acrylate compound include (meth)acrylates containing a chain aliphatic skeleton, (meth)acrylates containing a cyclic aliphatic skeleton, oligoester (meth)acrylates, urethane (meth)acrylate oligomers, epoxy-modified (meth)acrylates, polyalkylene glycol (meth)acrylates, polyether (meth)acrylates other than polyalkylene glycol (meth)acrylates, and itaconic acid oligomers. The energy ray-curable resin may be contained alone or in combination of two or more types. When two or more types of energy ray-curable resins are contained, the combination and ratio of the energy ray-curable resins can be selected depending on the purpose.

The weight average molecular weight (Mw) of the energy ray-curable resin is preferably 100 or more and 30,000 or less, and more preferably 300 or more and 10,000 or less.

When the resin layer 15 is an energy ray-curable resin layer, the energy ray-curable resin may be combined with a thermoplastic resin, as described below. The combination and ratio of the energy ray-curable resin and the thermoplastic resin can be selected according to the purpose.

When the resin layer 15 is a thermosetting resin layer, the resin layer 15 contains a thermosetting resin. The thermosetting resin used in the resin layer 15 is 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. Among these, from the viewpoint of suitability for curing using an imidazole curing catalyst, it is preferable to use one or more of the following thermosetting resins: epoxy resins, phenolic resins, melamine resins, urea resins, amine compounds, and acid anhydride compounds. In particular, from the viewpoint of exhibiting excellent curing properties, it is preferable to use 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.

When the resin layer 15 is a moisture-curable resin layer, the resin layer 15 contains a moisture-curable resin. The moisture-curable resin used in the resin layer 15 is not particularly limited, but examples include urethane resin (a resin formed when isocyanate groups are cured by moisture) and modified silicone resin.

When at least one of an energy ray-curable resin and a thermosetting resin is used in the resin layer 15, it is preferable that a photopolymerization initiator, a thermal polymerization initiator, or the like is used in the resin layer 15. When the resin layer 15 contains an energy ray-curable resin, a crosslinked structure is formed in the resin layer 15 by using a photopolymerization initiator, or the like. When the resin layer 15 contains a thermosetting resin, a crosslinked structure is formed in the resin layer 15 by using a thermal polymerization initiator, or the like. This makes it easier for the conductive linear member 13 to be more firmly protected by the resin layer 15.

Photopolymerization initiators include 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.

Thermal polymerization initiators include hydrogen peroxide, peroxodisulfates (ammonium peroxodisulfate, sodium peroxodisulfate, potassium peroxodisulfate, etc.), azo compounds (2,2'-azobis(2-amidinopropane) dihydrochloride, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobisisobutyronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), etc.), and organic peroxides (benzoyl peroxide, lauroyl peroxide, peracetic acid, persuccinic acid, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, etc.).

These polymerization initiators can be used alone or in combination of two or more. When these polymerization initiators are used to form a crosslinked structure, the amount of polymerization initiator used is preferably 0.1 parts by mass or more and 100 parts by mass or less, more preferably 1 part by mass or more and 100 parts by mass or less, and even more preferably 1 part by mass or more and 10 parts by mass or less, per 100 parts by mass of at least one of the energy ray-curable resin and the thermosetting resin.

The resin layer 15 may not be curable, and may be a layer made of, for example, a thermoplastic resin composition. The thermoplastic resin layer can be softened by adding a solvent (water, solvent, etc.) to the thermoplastic resin composition. This makes it easier to arrange the conductive linear members 13 in the resin layer 15 when forming them in the resin layer 15. Meanwhile, the thermoplastic resin layer can be dried and solidified by volatilizing the solvent in the thermoplastic resin composition.

Examples of thermoplastic resins include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl acetate, polyurethane, polyether, polyethersulfone, polyimide, and acrylic resin. Examples of solvents include alcohol-based solvents, ketone-based solvents, ester-based solvents, ether-based solvents, hydrocarbon-based solvents, and alkyl halide solvents, as well as water.

The resin layer 15 may contain an inorganic filler. By including an inorganic filler, the hardness of the resin layer 15 after curing can be further improved. The thermal conductivity of the resin layer 15 can also be improved.

Examples of inorganic fillers include inorganic powders (e.g., powders of silica, alumina, talc, calcium carbonate, titanium white, red iron oxide, silicon carbide, metals, and boron nitride), beads made by spheroidizing inorganic powders, single-crystal fibers, and glass fibers. Of these, silica filler and alumina filler are preferred as inorganic fillers. These inorganic fillers may be used singly or in combination of two or more.

The resin layer 15 may contain other components. Examples of other components include well-known additives such as organic solvents, flame retardants, tackifiers, UV absorbers, antioxidants, preservatives, antifungal agents, plasticizers, antifoaming agents, and wettability adjusters.

The thickness of the resin layer 15 may be determined depending on the application of the sheet-like conductive member 12. For example, from the standpoint of adhesiveness, the thickness of the resin layer 15 is preferably 3 μm or more and 150 μm or less, and more preferably 5 μm or more and 100 μm or less.

(First release sheet)
The first release sheet 18 is not particularly limited as long as it has releasability. The first release sheet 18 may be, for example, a release sheet including a release substrate and a release agent layer formed by applying a release agent to the release substrate. The release agent layer provided on the release substrate may be provided on only one side of the release substrate, or may be provided on both sides of the release substrate. Examples of release substrates include paper substrates, laminated paper in which a thermoplastic resin is laminated on a substrate such as paper or nonwoven fabric, and thermoplastic resin films. Examples of release agents include olefin-based resins, rubber-based elastomers, long-chain alkyl resins, alkyd-based resins, fluorine-based resins, and silicone-based resins.

(Second release sheet)
The second release sheet 19 is not particularly limited as long as it has releasability. It is preferable that the second release sheet 19 is a release sheet different from the first release sheet 18 so as to have a heavier release than the first release sheet 18. The second release sheet 19 may be a release sheet comprising a release substrate and a release agent layer provided on the release substrate. The release substrate and the release agent contained in the release agent layer can be selected from the release substrates and release agents exemplified for the first release sheet 18. Furthermore, the second release sheet 19 can also be, for example, a preferred embodiment of the second release sheet 19 described in the second embodiment below.

The thickness of the first release sheet 18 and the second release sheet 19 is not particularly limited and may be, for example, 20 μm or more and 200 μm or less. When the first release sheet 18 and the second release sheet 19 comprise, for example, a release substrate and a release agent layer provided on the release substrate, the thickness of the release agent layer is not particularly limited and may be, for example, 0.01 μm or more and 2.0 μm or less. The thickness of the release substrate is not particularly limited and may be, for example, 3 μm or more and 150 μm or less.

<First exposure process>
3(A) and 3(B), in the first exposure step, the first release sheet 18 provided in the laminate 120 is peeled off to expose the first surface 12A of the sheet-like conductive member 12. Then, as shown in FIG. 3(B), the first surface 12A of the sheet-like conductive member 12 is exposed, thereby exposing the resin layer 15 provided in the sheet-like conductive member 12. The method for peeling off the first release sheet 18 in the first exposure step is not particularly limited, and may be a mechanical peeling method or a manual peeling method. The direction in which the first release sheet 18 is peeled off is not particularly limited as long as the first release sheet 18 is peelable and the first surface 12A of the sheet-like conductive member 12 can be exposed.

In this embodiment, neither the first release sheet 18 nor the second release sheet 19 is peeled off during the first exposure step. This makes it easier to prevent contamination of the attachment device, for example, when attaching the sheet to the target object.

<Application process>
(Object)
The object 90 used in the bonding step will be described. In Figures 3(C) and 3(D), the object 90 has a flat surface (flat surface) that is bonded to the exposed first surface 12A of the sheet-like conductive member 12.

In the object 90 of this embodiment, the surface to be bonded to the exposed first surface 12A needs to be a flat surface, and the surfaces other than the bonded surface may have any shape.

The material of the object 90 is not particularly limited. The material of the object 90 may be an insulating material or a non-insulating material. The material of the object 90 is preferably an insulating material. The insulating properties of the object 90 may be, for example, such that the volume resistivity of the object 90 is 10 ¹² Ω·cm or more. Examples of the material of the object 90 include plastic, glass, ceramic, stone, wood, pulp laminated wood, nonwoven fabric, woven fabric, and insulating-coated metal.

Referring to FIG. 3(C), in the bonding process, the exposed first surface 12A of the sheet-like conductive member 12 is bonded to the surface of the object 90 (i.e., the surface to be bonded of the object). The bonding method for bonding the exposed first surface 12A to the surface to be bonded of the object 90 is not particularly limited. It may be a mechanical bonding method or a manual bonding method. From the standpoint of work efficiency, a mechanical bonding method using a bonding device is preferable. The bonding device is not particularly limited, and various laminator devices may be used, for example. Specifically, when the surface to be bonded of the object 90 is a flat surface, bonding of the first surface 12A of the sheet-like conductive member 12 to the surface to be bonded of the object 90 can be performed using a conventional laminator device such as a roll press.

<Curing process>
In the present embodiment, for example, when the resin layer 15 is a curable resin, it is preferable to include a curing step described below. The curing step is a step that is performed as needed, and even when the resin layer 15 is a curable resin, the curing step may not be performed.

The curing process is a process in which the resin layer 15, which forms part of the first surface 12A and part of the second surface 12B of the sheet-like conductive member 12, is a curable resin and is bonded to the object 90 after the bonding process. Specifically, the curing process is a process in which the resin layer 15 is hardened after the first surface 12A exposed in the first peeling process is bonded to the surface of the object 90 and before the second release sheet 19 is peeled off (i.e., before the second exposing process). In the curing process, the resin layer may be hardened by heat, light, or a combination of both. The resin layer may also be hardened by moisture. The method for hardening the resin layer in the curing process may be selected depending on the components of the resin composition used to form the resin layer 15. The curable resin layer serving as the resin layer 15 is preferably the outermost layer, from the viewpoint of enhancing the scratch resistance of the surface of the conductive structure 320 and making it easier to maintain the conductivity of the conductive structure 320.

When the resin layer 15 is, for example, an energy ray-curable resin layer containing an acrylate compound having a (meth)acryloyl group, curing the sheet-shaped conductive member 12 without peeling off the second release sheet 19 facilitates curing of the energy ray-curable resin layer. This is presumably because the second release sheet 19 suppresses oxygen inhibition when curing a resin layer containing an acrylate compound having a (meth)acryloyl group.

<Second exposure process>
3(D), in the second exposing step, the second release sheet 19 is peeled off to expose the second surface 12B of the sheet-like conductive member 12. The exposure of the second surface 12B of the sheet-like conductive member 12 exposes the resin layer 15 of the sheet-like conductive member 12. The method for peeling off the second release sheet 19 in the second exposing step is not particularly limited, and may be the same method as in the first exposing step described above, as long as the second release sheet 19 is peelable and the second surface 12B of the sheet-like conductive member 12 can be exposed.

In this embodiment, the second exposure step exposes the second surface 12B of the sheet-like conductive member 12, which can serve as the outermost surface of the conductive structure 320. If the resin layer 15 is a curable resin, the cured resin layer 15 that constitutes part of the second surface 12B can serve as the outermost surface of the conductive structure 320, thereby reducing tackiness and providing excellent scratch resistance to the surface of the conductive structure 320. Furthermore, the second exposure step exposes the second surface 12B of the sheet-like conductive member 12, allowing a protective layer to be provided on the resin layer 15. Furthermore, the second exposure step exposes the second surface 12B of the sheet-like conductive member 12, allowing an electrode to be provided on the resin layer 15 and electrically connected to the conductive linear body 13. If the resin layer 15 contains an adhesive, an object the same as or different from the object 90 can be attached to the exposed second surface 12B.

<Effects of the First Embodiment>
According to this embodiment, the following effects can be achieved.
(1) Because the laminate 120 does not include a base material, it is possible to reduce the thickness of the sheet-like conductive member 12. Therefore, when the sheet-like conductive member 12 including the conductive linear members 13 and the resin layer 15 is attached to the object 90, a conductive structure is obtained in which the sheet-like conductive member 12 has improved conformability to the object 90.
(2) When the sheet-like conductive member 12 including the conductive linear bodies 13 and the resin layer 15 is used by being attached to the object 90, the first release sheet 18 arranged on one side of the sheet-like conductive member 12 is peeled off, the surface from which the release sheet has been peeled off is attached to the object 90, and then the second release sheet 19 arranged on the other side of the sheet-like conductive member 12 is peeled off. This prevents contamination of an attachment device (not shown) when attaching the sheet-like conductive member 12 to the object 90.

[Second embodiment]
The second embodiment will be described below with reference to the drawings. The present invention is not limited to the contents of the embodiment. Note that in the drawings, some parts are illustrated enlarged or reduced in size for ease of explanation.

As shown in Figure 5, the second embodiment is a method for manufacturing a conductive structure 400 including an object 92 and a sheet-like conductive member 20 provided in contact with the object 92. Figures 5(A) to 5(D) are schematic diagrams for explaining the method for manufacturing the conductive structure 400 according to the second embodiment, showing schematic diagrams of each step.

The second embodiment differs from the first embodiment in that, instead of preparing a laminate 120 including a sheet-like conductive member 12 as in the first embodiment, a laminate 200 using a sheet-like conductive member 20 is prepared (see FIG. 4). The second embodiment also differs in that the surface to be bonded to the first surface 20A of the sheet-like conductive member 20 (i.e., the surface to be attached) is a target object 92, which is a three-dimensional structure having a three-dimensional shape (see FIGS. 5(C) and 5(D)). In other words, in the second embodiment, the first surface 20A of the sheet-like conductive member 20 is bonded to the target object 92, and the second surface 20B of the sheet-like conductive member 20 can be configured as the outermost surface of the conductive structure 400.

The method for manufacturing the conductive structure 400 according to this embodiment includes a laminate preparation step, a first exposure step, an attachment step, and a second exposure step. Specific examples of the laminate preparation step, the first exposure step, and the second exposure step are the same as those described in the first embodiment, for example, except that the laminate 200 and the target object 92 are used. Furthermore, in this embodiment, if the resin layer 15 is a curable resin, a curing step may be included. Specific examples of the curing step are the same as those described in the first embodiment, for example.

The following explanation will focus on differences from the first embodiment, and overlapping explanations will be omitted or simplified. Components similar to those in the first embodiment will be assigned the same reference numerals, and explanations will be omitted or simplified.

In this embodiment, the bonding process involves bonding the sheet-like conductive member 20 to an object 92, which is a three-dimensional structure whose surface to be bonded has a three-dimensional shape.

In this specification, the three-dimensional shape includes the following shapes (I) and (II).
(I) The surface of the object to be bonded to the exposed surface of the sheet-like conductive member is not a flat surface, but is a curved surface or has a shape including a surface having an uneven surface.
(II) When the surface of the object to be bonded to the exposed surface of the sheet-like conductive member includes a flat surface, the surface has a shape including one flat surface and another surface, and the other surface includes at least one surface selected from the group consisting of a flat surface, a curved surface, and an uneven surface.

The surface to be attached of the object only needs to be able to be attached to the exposed surface of the sheet-like conductive member. When the three-dimensional shape is (I) above, the surface to be attached of the object may be one surface or two or more multiple surfaces. When the surface to be attached has multiple surfaces, all of the surfaces may be curved or uneven. When the three-dimensional shape is (II) above, the surface to be attached of the object has one flat surface and one or more other surfaces. The other surfaces may be flat, curved, or uneven. The uneven surface may have uneven portions on a flat surface, or may have uneven portions on a curved surface. The concave and convex portions of the uneven portion may be formed continuously or intermittently.
In this specification, if the object has only one surface to which the attachment is made and the surface to which the attachment is made is a flat surface, the object is not considered to have a three-dimensional shape.

The three-dimensional structure having a three-dimensional shape may be, for example, a molded body obtained using various materials and various molding methods. For example, when the surface to be attached of the object 92 is a molded body as a three-dimensional structure having a three-dimensional shape, examples of such molded bodies include housings for electrical appliances, vehicle interior and exterior parts, building materials, and interior materials. Furthermore, when the sheet-like conductive member 20 is used as a heating element of the conductive structure 400, examples of uses for such heating elements include defoggers and deicers. In this case, examples of the object 92 include mirrors in bathrooms, windows of transportation devices (such as passenger cars, trains, ships, and aircraft), windows of buildings, eyewear, the illuminated surfaces of traffic lights, and signs.

In the bonding step of this embodiment, it is preferable to use various molding devices (for example, molding devices used in molding methods such as vacuum forming, pressure forming, vacuum-pressure forming, and press forming). Of the various molding devices, it is more preferable to use a molding device used for vacuum-pressure forming (hereinafter sometimes referred to as TOM forming) for the bonding step of this embodiment. Below, in the second embodiment, a case will be described in which the bonding step is a step of bonding the first surface 20A of the sheet-like conductive member 20 to the surface of the object 92 using vacuum-pressure forming (TOM forming: Three-dimensional Overlay Method).

<Laminate preparation step>
The laminate 200 has the same structure as the sheet-like conductive member 12 described in the first embodiment, except that, in a plan view of the sheet-like conductive member 20, all of the multiple conductive linear members 23 have a wave shape. The laminate 200 can be fabricated, for example, by the same procedure (procedure 1 or procedure 2) as the laminate 120 described in the first embodiment. To form the conductive linear members 23 into a wave shape, for example, the conductive linear members 23 may be arranged on the resin layer 15 while moving the resin layer 15 and the conductive linear members 23 relative to each other. The wave shape is not limited to the wave shape shown in FIG. 4 , and may be, for example, a sine wave, a circular wave, a rectangular wave, a triangular wave, a sawtooth wave, or other wave shapes. Specific examples of the conductive linear members 23 other than the wave shape are the same as those of the conductive linear members 13 described in the first embodiment.

If the multiple conductive linear bodies 23 are wavy, for example, when the first surface 20A of the sheet-like conductive member 20 is bonded to the surface of the object 92 by TOM forming, the sheet-like conductive member 20 can easily follow the shape of the object 92. TOM forming also has the advantage of preventing breakage of the conductive linear bodies 23 when the first surface 20A of the sheet-like conductive member 20 is bonded to the surface of the object 92.

In this embodiment, the second release sheet 19 can be the same as the specific example exemplified in the first embodiment. The second release sheet 19 is peeled off after the first surface 20A of the sheet-like conductive member 20 is attached to the surface of the object 92 to be attached. Therefore, from the viewpoint of ensuring excellent conformability of the sheet-like conductive member 20 and the second release sheet 19 to the object 92, the second release sheet 19 is a release sheet comprising a release substrate and a release agent layer provided on at least one surface of the release substrate, and the release substrate is preferably a resin sheet. The release substrate is more preferably a polyolefin film, and even more preferably a polypropylene film. The release agent constituting the release agent layer can be selected from the same release agents exemplified for the first release sheet 18 in the first embodiment. In particular, if the second release sheet 19 comprises a release substrate and a release agent layer provided on at least one surface of the release substrate, and the release substrate is a polypropylene film, better conformability is likely to be achieved when the first surface 20A of the sheet-like conductive member 20 is bonded to the surface of the object 92 by TOM molding.

<Application process>
Referring to Figure 5(C), in the bonding process, the first surface 20A of the sheet-like conductive member 20 exposed by peeling off the first release sheet 18 is bonded to the surface of the object 92 by TOM molding. As shown in Figures 5(C) and 5(D), the object 92 used in this embodiment is a three-dimensional structure with a specific shape. The object 92 has a C-shape in a cross-sectional view in the thickness direction, with one surface having a convex curved surface and the other surface having a concave curved surface in one direction. The surface having the convex curved surface is the surface that is bonded to the exposed first surface 20A of the sheet-like conductive member 20.

In this embodiment, the object 92 is exemplified as a three-dimensional structure having a three-dimensional shape in which the surface to be bonded to the first surface 20A of the sheet-like conductive member 20 is a C-shaped curved surface, but is not limited thereto. The object 92 may also be a three-dimensional structure having a surface to be bonded to the first surface 20A of the sheet-like conductive member 20 having another three-dimensional shape. A three-dimensional structure in which the surface to be bonded of the object 92 has a three-dimensional shape, such as a curved surface, is preferred because it is easier to achieve the effects of TOM molding. The surface to be bonded of the object 92 may also be a structure in which only a flat surface is bonded. Furthermore, the three-dimensional structure of the entire object 92 may be, for example, cylindrical, columnar, prismatic, pyramidal, spherical, or hemispherical. The material of the object 92 used in this embodiment is not particularly limited, and the same material as the material of the object 90 described in the first embodiment can be used.

By using TOM molding to bond the sheet-like conductive member 20 in the bonding process, the sheet-like conductive member 20 is deformed to conform to the surface shape of the object 92, which is a three-dimensional structure having a three-dimensional shape, and is then bonded to the surface of the object 92. Therefore, if the bonding process is a process of bonding the first surface 20A exposed in the first exposure process to the surface of the object 92 by TOM molding, the sheet-like conductive member 20 can be precisely shaped to the shape of the object 92 and can be precisely adhered to the object 92. From this perspective, when TOM molding is used in the bonding process, it is preferable that the object 92 be a three-dimensional structure having a three-dimensional shape. Specific examples include three-dimensional molded products formed using various molding devices.

The bonding process using TOM molding includes, for example, the following steps.
(s1) A process of placing a sheet-shaped conductive member 20 at the boundary between a first box and a second box in a TOM molding device equipped with a chamber box having a first box and a second box, and placing an object 92 in the second box.
(s2) A step of reducing the pressure inside the first box and the second box.
(s3) A step of heating the sheet-shaped conductive member 20 under reduced pressure.
(s4) After the sheet-shaped conductive member 20 reaches a predetermined temperature, the object 92 is moved toward the first box, and the sheet-shaped conductive member 20 is shaped to the shape of the object 92.
(s5) A step of applying pressure inside the first box to bond the sheet-like conductive member 20 and the object 92 together.

A TOM molding device, for example, includes a chamber box divided into two parts: a first box and a second box. The first box has a section that opens toward the second box, and the second box has a section that opens toward the first box. The first box and the second box are arranged with their open sections facing each other. The first box includes a decompression device that sucks and exhausts air from inside the first box to reduce the pressure, a pressurization device that pumps air into the first box to pressurize it, and a heating device located within the first box. The second box includes a decompression device that sucks and exhausts air from the second box to reduce the pressure. One example of a TOM molding device is the TOM molding device manufactured by Fuse Vacuum Co., Ltd.

In the above step (s1), the sheet-like conductive member 20 is placed at the boundary between the first box and the second box, and the object 92 is placed in the second box. At this time, the sheet-like conductive member 20 is placed with the first surface 20A of the sheet-like conductive member 20 exposed in the first exposure step facing the object 92 placed in the second box. The object 92 is placed with the convex curved surface facing the first surface 20A of the sheet-like conductive member 20. In step (s1), the inside of the chamber box is open to atmospheric pressure.

In the above step (s2), the pressure inside both the first box and the second box is reduced. The insides of the first box and the second box are reduced to a predetermined reduced pressure. The reduced pressure is not particularly limited, and examples of the reduced pressure include a vacuum pressure in the range of 100 Pa or more and 1000 Pa or less.

In the above step (s3), the sheet-shaped conductive member 20 is heated under reduced pressure using a heating device such as an infrared heater. The sheet-shaped conductive member 20 is heated until its surface temperature reaches a predetermined temperature. The surface temperature of the heated sheet-shaped conductive member 20 can be, for example, 80°C or higher and 180°C or lower.

In the above step (s4), after the surface temperature of the sheet-like conductive member 20 reaches a predetermined temperature, the object 92 is moved toward the first box. As the object 92 is moved toward the first box, the sheet-like conductive member 20 is pressed against the object 92. By being pressed against the surface of the object 92, the sheet-like conductive member 20 conforms to the curved shape of the convex shape of the object 92. As a result, the sheet-like conductive member 20 is shaped to match the shape of the object 92 and is simultaneously attached to the object 92.

In the above-mentioned step (s5), air is introduced into the first box, creating a pressurized state inside the first box, thereby bonding the first surface 20A of the sheet-like conductive member 20 to the surface of the object 92. The pressurized state may be, for example, atmospheric pressure (0.1 MPa). Compressed air may also be introduced into the first box. In this case, the pressurized state inside the first box may be in a range from greater than atmospheric pressure (over 0.1 MPa) to atmospheric pressure + 2 MPa or less. In other words, in step (s5), the pressure in the pressurized state inside the first box may be in a range from atmospheric pressure (0.1 MPa) to 2 MPa or less.

After the above step (s5), air is also introduced into the second box to return the pressure inside the chamber box to atmospheric pressure, and the conductive structure 400 is removed before the second release sheet 19 is peeled off.

<Operation and effect of the second embodiment>
(1) According to this embodiment, it is possible to achieve the same effects as the effects (1) and (2) of the first embodiment described above.
(2) According to this embodiment, TOM molding is applied as the bonding step, and the exposed surface of the sheet-like conductive member 20 is bonded to the surface of the object 92. Therefore, the sheet-like conductive member 20 is precisely shaped to the shape of the object 92, which is a three-dimensional structure having a three-dimensional shape, and can be precisely bonded to the object 92. Furthermore, even if the object 92 is a three-dimensional structure having a three-dimensional shape, the sheet-like conductive member 20 can be easily bonded.

[Third embodiment]
Next, a third embodiment of the present invention will be described with reference to the drawings. The present invention is not limited to the content of the embodiment. Note that in the drawings, some parts are illustrated enlarged or reduced in size for ease of explanation.

As shown in Figure 6, the third embodiment is a method for manufacturing a conductive structure 321 including an object 90 and a sheet-like conductive member 12 provided in contact with the object 90. Figures 6(A) to 6(E) are schematic diagrams for explaining the method for manufacturing a conductive structure 321 according to the second embodiment, showing schematic diagrams of each step.

The third embodiment differs from the first embodiment in that it includes a protective layer formation process in which a protective layer 60 is provided on the exposed second surface 12B of the sheet-shaped conductive member 12 after the second exposure process.

That is, the manufacturing method of the conductive structure 321 according to this embodiment includes a laminate preparation process, a first exposure process, a bonding process, a second exposure process, and a protective layer formation process. In this embodiment, specific examples of the laminate preparation process, the first exposure process, and the second exposure process are similar to those described in the first embodiment, for example. Specific examples of the bonding process are similar to those described in the first embodiment and the second embodiment, for example. That is, in this embodiment, the object 90 used in the bonding process may have, for example, a single surface to be bonded and the non-bonded surface may be a flat surface, or may be a three-dimensional structure having a three-dimensional shape with a surface other than a flat surface. That is, the object 90 may or may not have a three-dimensional shape. The bonding method used in the bonding process may be, for example, a roll press or other conventional laminator device, as well as various molding devices used in vacuum forming, pressure forming, TOM forming, press molding, and the like. Furthermore, in this embodiment, if the resin layer 15 is a curable resin, a curing process may be included. Specific examples of the curing process are similar to those described in the first embodiment.

The following explanation will focus on differences from the first embodiment, and overlapping explanations will be omitted or simplified. Components similar to those in the first embodiment will be assigned the same reference numerals, and explanations will be omitted or simplified.

<Protective layer formation process>
As shown in FIG. 6(E), the protective layer forming step is a step of providing a protective layer 60 on the exposed second surface 12B after the second exposing step.

Referring to FIG. 6(E), in the protective layer forming process, a protective layer 60 is provided on the second surface 12B of the sheet-like conductive member 12. In this embodiment, the protective layer 60 covers the resin layer 15 and the conductive linear body 13. The protective layer 60 protects the second surface 12B of the sheet-like conductive member 12. The protective layer 60 is a layer that, for example, enhances the scratch resistance of the surface of the conductive structure 321 and facilitates maintaining the conductivity of the conductive structure 321. Therefore, the protective layer forming process is a process that is provided after the second surface 12B of the sheet-like conductive member 12 is exposed in the second exposure process. From the perspective of, for example, enhancing the scratch resistance of the surface of the conductive structure 321 and facilitating maintaining the conductivity of the conductive structure 321, the protective layer 60 is preferably the outermost layer. Note that, for example, an electrode placement process, described in the third embodiment below, may be provided between the second exposure process and the protective layer forming process.

The protective layer formation process is not limited to the form in which a protective layer 60 is formed to cover the resin layer 15 and the conductive linear body 13, as shown in FIG. 6(E). Although not shown, the protective layer formation process may also be a process in which the protective layer 60 is provided in a position other than the portion where the conductive linear body 13 is disposed on the resin layer 15.

The protective layer 60 may be formed, for example, from a thermoplastic resin film, or from a resin composition containing a curable resin such as a thermosetting resin or an energy ray-curable resin. When the protective layer 60 is formed from a thermoplastic resin film, the protective layer 60 may be provided by applying the thermoplastic resin film to the second surface 12B of the sheet-like conductive member 12 exposed in the second exposure step using methods such as vacuum forming, pressure forming, TOM forming, and press molding. When the protective layer 60 is formed from a resin composition containing a curable resin, the protective layer 60 may be provided, for example, by applying a liquid resin composition containing the curable resin and curing it. In this case, the protective layer 60 may be provided, for example, by applying a resin composition containing at least one of a thermosetting resin and an energy ray-curable resin to the second surface 12B, optionally drying the applied composition, and then curing the applied composition by at least one of a heat treatment and an energy ray irradiation treatment, depending on the resin components contained in the resin composition. Examples of methods for applying a liquid resin composition containing a curable resin to the second surface 12B include dipping, spraying, inkjet printing, and transfer printing.

In this specification, the protective layer 60 is distinguished from the first release sheet 18 and the second release sheet 19. In this embodiment, the first release sheet 18 and the second release sheet 19 are temporarily provided on the first surface 12A and the second surface 12B of the sheet-like conductive member 12, and are peeled off from the laminate 120 for use. On the other hand, in this embodiment, the protective layer 60 is provided on the second surface 12B of the sheet-like conductive member 12, and is not intentionally peeled off.

(protective layer)
Thermoplastic resin films and curable resins that can be applied to the protective layer 60 will be described.

When the protective layer 60 is formed by methods such as vacuum forming, pressure forming, TOM forming, and press forming, it is preferably formed from a thermoplastic resin film from the viewpoint of its ability to conform to the second surface 12B of the sheet-like conductive member 12. Examples of thermoplastic resins used in the thermoplastic resin film for the protective layer 60 include polyolefin resins, polyester resins, polyacrylic resins, polystyrene resins, polyimide resins, polyimideamide resins, polyamide resins, polyurethane resins, polycarbonate resins, polyarylate resins, melamine resins, epoxy resins, urethane resins, silicone resins, and fluororesins. The thermoplastic resins used in the thermoplastic resin film may contain one or more of these resins alone or in combination.

From the perspective of surface protection, the protective layer 60 is also preferably formed from a resin composition containing a curable resin. When formed from a resin composition containing a curable resin, the protective layer 60 is provided by applying (e.g., dipping, spraying, inkjet printing, transfer printing, etc.) a liquid resin composition containing the curable resin. Examples of curable resins include resin compositions containing an epoxy resin and a curing agent, resin compositions containing a (meth)acrylic polyol and a polyisocyanate compound, resin compositions capable of radical polymerization, and resin compositions containing a polymerizable compound having a (meth)acryloyl group and a photopolymerization initiator.

The protective layer 60 may contain additives such as inorganic fillers, colorants, antioxidants, light stabilizers, flame retardants, conductive agents, antistatic agents, and plasticizers.

The inorganic filler contained in the protective layer 60 may be, for example, an inorganic filler having a thermal conductivity of 10 W/mK or greater. Specific examples of inorganic fillers include metal particles, metal oxide particles, metal hydroxide particles, and metal nitride particles. The content of the inorganic filler may be 0% by mass or greater and 90% by mass or less of the entire protective layer 60.

The colorant contained in the protective layer 60 may be, for example, an inorganic pigment, an organic pigment, or a dye.

From the perspective of ensuring protective function, the thickness of the protective layer 60 may be, for example, in the range of 0.1 μm or more and 2500 μm or less. When the protective layer 60 is formed by applying a liquid resin composition containing a curable resin, the thickness of the protective layer 60 is preferably 0.1 μm or more and 10 μm or less. When the protective layer 60 is formed from a thermoplastic resin film, the thickness of the protective layer 60 is preferably 8 μm or more and 2500 μm or less.

<Operation and effect of the third embodiment>
(1) According to this embodiment, it is possible to achieve the same effects as the effects (1) and (2) of the first embodiment described above.
(2) Furthermore, according to this embodiment, since the process of providing the protective layer 60 is included, it is possible to, for example, increase the scratch resistance of the surface of the conductive structure 321 and make it easier to maintain conductivity.

[Fourth embodiment]
The fourth embodiment will be described below with reference to the drawings. The present invention is not limited to the contents of the embodiment. Note that in the drawings, some parts are illustrated enlarged or reduced in size for ease of explanation.

As shown in Figure 7, the fourth embodiment is a method for manufacturing a conductive structure 322 that includes an object 90 and a sheet-like conductive member 12 that is provided in contact with the object 90. Figures 7(A) to 7(E) are schematic diagrams for explaining the method for manufacturing a conductive structure 322 according to the third embodiment, and show schematic diagrams of each step.

The fourth embodiment differs from the first embodiment in the process subsequent to the second exposure process. That is, the fourth embodiment differs from the first embodiment in that it includes an electrode placement process in which a pair of electrodes 50 are placed on the exposed second surface 12B of the sheet-shaped conductive member 12 so as to be electrically connected to the conductive linear body 13.

The manufacturing method for the conductive structure 322 according to this embodiment includes a laminate preparation process, a first exposure process, a bonding process, a second exposure process, and an electrode arrangement process. Specific examples of the laminate preparation process, the first exposure process, and the second exposure process in this embodiment are, for example, similar to those described in the first embodiment. Specific examples of the bonding process are, for example, similar to those described in the first embodiment and the second embodiment. That is, in this embodiment, the bonding process may be performed in the same manner as in the third embodiment. Furthermore, in this embodiment, if the resin layer 15 is a curable resin, a curing process may be included. Specific examples of the curing process are, for example, similar to those described in the first embodiment.

The following explanation will focus on differences from the first embodiment, and overlapping explanations will be omitted or simplified. Components similar to those in the first embodiment will be assigned the same reference numerals, and explanations will be omitted or simplified.

<Electrode placement process>
The electrode arrangement step is a step of arranging a pair of electrodes 50 on the exposed second surface 12B after the second exposure step so as to be electrically connected to the conductive linear body 13. In the present embodiment, the second surface 12B is exposed as shown in Fig. 7(D), and then, as shown in Fig. 7(E), the electrodes 50 are arranged on the exposed second surface 12B so as to be electrically connected to the conductive linear body 13. Then, as shown in Fig. 8, the electrodes 50 are arranged as a pair of electrodes 50 on the exposed second surface 12B so as to be electrically connected to the conductive linear body 13.

Referring to FIG. 7(E), in the electrode arrangement process, an electrode 50 is provided on the second surface 12B of the sheet-like conductive member 12 so as to be electrically connected to the conductive linear body 13. The electrode 50 forms a pair with another electrode not shown in FIG. 7(E). Then, as shown in FIG. 8, the electrodes 50 are attached to both axial end sides of the conductive linear body 13 arranged on the sheet-like conductive member 12, thereby providing a pair of electrodes 50. In this way, the pair of electrodes 50 is arranged in electrical connection with the conductive linear body 13. In this embodiment, the pair of electrodes 50 is used to supply current to the conductive linear body 13.

(electrode)
The following describes materials that can be used for the electrode 50. The electrode 50 can be formed using known electrode materials. Examples of electrode materials include conductive paste (such as silver paste), metal foil (such as copper foil), and metal wire.

When the electrode material is a metal foil or metal wire, the metal of the metal foil or metal wire can be a metal (copper, aluminum, tungsten, iron, molybdenum, nickel, titanium, silver, gold, etc.) or an alloy containing two or more metals (for example, steel such as stainless steel or carbon steel, brass, phosphor bronze, zirconium-copper alloy, beryllium copper, iron-nickel, nichrome, nickel-titanium, Kanthal, Hastelloy, rhenium-tungsten, etc.). The metal foil or metal wire may also be plated with gold, tin, zinc, silver, nickel, chromium, nickel-chromium alloy, solder, etc.

The width of one of the pair of electrodes 50, when viewed in plan on the sheet-like conductive member 12, is preferably 10 mm or less, more preferably 3000 μm or less, and even more preferably 1500 μm or less. If one electrode is a metal wire, the width of the electrode is the diameter of the metal wire. If two or more metal wires are used, the width of one electrode is the sum of the diameters of the metal wires.

The thickness of the electrode 50 is preferably 2 μm or more and 200 μm or less, more preferably 2 μm or more and 170 μm or less, and even more preferably 10 μm or more and 150 μm or less. If the thickness of the electrode 50 is within the above range, the electrical conductivity is high and the resistance is low, and the resistance value with the conductive linear body 13 can be kept low. In addition, sufficient strength as an electrode 50 can be obtained. Note that if the electrode 50 is a metal wire, the thickness of the electrode 50 is the diameter of the metal wire.

When the conductive structure 322 is applied to a heater, from the viewpoint of suppressing heat generation of the electrode 50, the volume resistivity of the electrode 50 is preferably in the following range. The volume resistivity of the electrode 50 is preferably 1.0×10 ⁻⁹ Ω·m or more and 1.0×10 ⁻⁵ Ω·m or less, and more preferably 5.0×10 ⁻⁹ Ω·m or more and 5.0×10 ⁻⁶ Ω·m or less. The volume resistivity of the electrode 50 is determined by the same method as the method for measuring the volume resistivity of the conductive linear body 13.

At the position where the pair of electrodes 50 are arranged, the distance from one electrode to the other electrode is not particularly limited, and the distance between one electrode and the other electrode may be, for example, 2 mm or more and 2 m or less, or 50 mm or more and 500 mm or less.

<Operation and effect of the fourth embodiment>
(1) According to this embodiment, it is possible to achieve the same effects as the effects (1) and (2) of the first embodiment described above.
(2) Furthermore, according to this embodiment, since the step of providing the pair of electrodes 50 is included, a current can be supplied to the conductive linear body 13 .

[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 first, third, and fourth embodiments, a laminate 120 is prepared in the laminate preparation step. However, depending on the purpose, a laminate 100 as shown in Figures 9 to 11 may also be prepared. In the laminate 100, the sheet-like conductive member 10 differs from the sheet-like conductive member 12 in the laminate 120 in that the entire circumferential surfaces of the multiple conductive linear members 13 are embedded in the resin layer 15. Therefore, the sheet-like conductive member 10 differs from the sheet-like conductive member 12 in that the first surface 10A and the second surface 10B of the sheet-like conductive member 10 are formed by the resin layer 15. In this case, apart from the preparation of the laminate 100, the specific examples of the laminate preparation step, first exposure step, and second exposure step are the same as those described in the first embodiment, and the specific example of the attachment step is the same as those described in the first and second embodiments. In other words, the details are the same except that the first surface 10A of the sheet-like conductive member 10 is attached to the object 90 or object 92. Furthermore, the laminate preparation step in the first, third, and fourth embodiments may involve preparing the laminate 200 prepared in the second embodiment. Furthermore, the conductive linear elements 13 of the laminate 100 may be arranged in a wave shape as described in the second embodiment. In Figures 9 to 11, the same components as those in the first embodiment are designated by the same reference numerals, and their description will be omitted.

When the manufacturing method according to the present invention includes an electrode arrangement step, it is preferable that the laminate preparation step prepares the laminate 120 prepared in the first, third, and fourth embodiments, or the laminate 200 prepared in the second embodiment. If the laminate is the laminate 120 or the laminate 200, it will be easier to electrically connect with the conductive linear body 13 or the conductive linear body 23.

The manufacturing method of the present invention may optionally include the following steps:

For example, in each embodiment, when the laminate 100 is prepared in the laminate preparation step, the entire circumferential surface of the conductive linear body 13 is disposed so as to be embedded in the resin layer 15. If it is desired to expose the conductive linear body 13 from the surface (second surface 10B) of the sheet-like conductive member 10, a removal step may be provided after the second exposure step to expose the conductive linear body 13 that is disposed so as to be embedded in the resin layer 15. The removal step is, for example, a step of removing a portion of the surface of the resin layer 15 after the second exposure step to expose the conductive linear body 13 from the surface of the resin layer 15.

Methods for removing the surface of the resin layer 15 include, for example, cutting or grinding. For example, when the conductive structure 300 shown in FIG. 11(E) is used as a heater, the removal step exposes the conductive linear body 13 from the surface of the resin layer 15, allowing the conductive structure 300 to be used as a more efficient heater. Furthermore, the removal step makes it easier to electrically connect the conductive linear body 13 to a pair of electrodes.

In each embodiment, when the laminate 100 is prepared, a protective layer forming process may be performed after the second exposure process. Furthermore, after the protective layer forming process, a removal process may be performed in which a portion of the resin layer 15 and the protective layer 60 is removed to expose the conductive linear body 13 from the surface of the protective layer 60. Alternatively, the protective layer forming process may be a process in which the protective layer 60 is provided on the resin layer 15 in a position other than the portion where the conductive linear body 13 is disposed. When the protective layer 60 is provided in a position other than the portion where the conductive linear body 13 is disposed, it is sufficient to remove a portion of the resin layer 15 to expose the conductive linear body 13, and the process of removing a portion of the protective layer 60 is not necessary.

Furthermore, after the removal process, an electrode placement process may be performed in which a pair of electrodes 50 are placed so as to electrically connect to the conductive linear body 13 exposed in the removal process.

In the second embodiment, at least one of a protective layer forming process and an electrode arranging process may be performed after the second exposure process. If both a protective layer forming process and an electrode arranging process are performed, the two processes may be performed in any order. Furthermore, in the third embodiment, the electrode arranging process may be performed after the protective layer forming process. If the electrode arranging process is performed after the protective layer forming process, a removal process similar to that described above may be performed after the protective layer forming process so that the conductive linear body 13 is exposed. Furthermore, in the fourth embodiment, the protective layer forming process may be performed after the electrode arranging process.

In each embodiment, the above-mentioned curing step may or may not be included.

In each embodiment, after the second exposure step, a bonding step may be provided in which the exposed second surface of the sheet-like conductive member is bonded to the surface of another object (not shown). In this case, the bonding step in which the sheet-like conductive member is bonded to the object (first object) after the first exposure step is the first bonding step, and the bonding step in which the sheet-like conductive member is bonded to another object (second object) after the second exposure step is the second bonding step. The first object and the second object may be the same or different. The bonded surface of the first object and the bonded surface of the second object may or may not have a three-dimensional shape. Furthermore, either the bonded surface of the first object or the bonded surface of the second object may have a three-dimensional shape, and the other may not have a three-dimensional shape.

10, 12, 20... Sheet-like conductive member, 13, 23... Conductive linear body, 15... Resin layer, 18... First release sheet, 19... Second release sheet, 50... Electrode, 60... Protective layer, 100, 120, 200... Laminate, 300, 320, 321, 322, 400... Conductive structure.

Claims (8)

A method for manufacturing a conductive structure including an object and a sheet-like conductive member provided in contact with the object,
The sheet-shaped conductive member is
a plurality of conductive linear bodies arranged at intervals, and a resin layer supporting the plurality of conductive linear bodies;
a plurality of the conductive linear members are arranged in contact with the resin layer,
the resin layer constitutes at least a part of a first surface of the sheet-shaped conductive member and at least a part of a second surface of the sheet-shaped conductive member,
The manufacturing method includes:
a laminate preparation step of preparing a laminate including the sheet-like conductive member, a first release sheet provided in contact with the first surface of the sheet-like conductive member, and a second release sheet provided in contact with the second surface opposite to the first surface;
a first exposing step of peeling the first release sheet from the laminate to expose the first surface;
a bonding step of bonding the exposed first surface to a surface of the object;
a second exposing step of peeling off the second release sheet that was not peeled off in the first exposing step to expose the second surface that was not exposed;
a protective layer forming step of providing a protective layer on the exposed second surface after the second exposure step;
Equipped with
The protective layer is the outermost layer .
A method for manufacturing a conductive structure. 2. The method for producing a conductive structure according to claim 1,
the resin layer is a curable resin layer,
After the bonding step, a curing step is further provided of curing the curable resin layer bonded to the object.
A method for manufacturing a conductive structure. 3. The method for producing a conductive structure according to claim 1 or 2,
The protective layer is formed of a thermoplastic resin film or a resin composition containing a curable resin.
A method for manufacturing a conductive structure. 4. The method for producing a conductive structure according to claim 1,
After the second exposing step, the method further includes an electrode arranging step of arranging a pair of electrodes on the exposed second surface so as to be electrically connected to the conductive linear body.
A method for manufacturing a conductive structure. 5. The method for producing a conductive structure according to claim 1,
The surface to be bonded to the first surface of the object is a three-dimensional structure having a three-dimensional shape.
A method for manufacturing a conductive structure. 6. The method for producing a conductive structure according to claim 1,
The bonding step is a step of bonding the first surface exposed in the first exposing step to a surface of the object by vacuum/pressure forming (TOM forming).
A method for manufacturing a conductive structure. 7. The method for producing a conductive structure according to claim 1,
In a plan view of the sheet-shaped conductive member, the conductive linear members have a wave shape.
A method for manufacturing a conductive structure. 8. The method for producing a conductive structure according to claim 1,
the second release sheet comprises a release substrate and a release agent layer provided on at least one surface of the release substrate;
The release substrate is a polypropylene film.
A method for manufacturing a conductive structure.