Method for manufacturing conductive base material, method for manufacturing electronic device, method for manufacturing electromagnetic wave shielding film, and method for manufacturing planar heating element

Abstract

To provide a method for manufacturing a conductive base material capable of improving adhesion of a conductor.SOLUTION: A method for manufacturing a conductive base material 10 includes the steps of: forming a curable resin layer 2 on a base material 1; forming a recess 31 on a surface opposite to the side of the base material 1 of the curable resin layer 2; arranging a conductive composition 4 containing conductive particles in the recess 31; curing the curable resin layer 2; and pressurizing the conductive composition 4 to form a conductor 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a conductive substrate, a method for producing an electronic device, a method for producing an electromagnetic wave shielding film, and a method for producing a sheet heating element. [Background technology]

[0002] A known technique involves forming a pattern on a substrate using a conductive composition containing conductive particles and then heating the pattern to obtain a conductive pattern. This technique is thought to be applicable to printed electronics, which has been actively developed in recent years. Printed electronics is a technology that uses printing technology to form electronic circuits, sensors, elements, etc. on a substrate such as a film.

[0003] Patent Document 1 (JP 2016-099861 A) describes a method for forming touch panel wiring, which includes a step of pressing a nanoprint plate, which has grooves with a fine uneven structure of several hundred nanometers formed on the surface, onto an ultraviolet-curable resin layer, and forming an imprinted portion by irradiating it with ultraviolet light, and then filling the obtained imprinted portion with conductive ink.

[0004] Patent Document 2 (JP 56-164591 A) describes a method for producing a rough-surface film, which includes the steps of applying an anti-peel resin to the surface of a base film, bringing it to a B-stage, pressing a rough-surface template onto the surface to transfer and form a rough surface, and curing the anti-peel resin with the rough surface formed, and these steps are carried out continuously. It also describes that a metal layer is then provided on the obtained rough-surface film by chemical plating or the like to form a circuit pattern. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-099861 [Patent Document 2] Japanese Patent Application Publication No. 56-164591 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the conventional technologies disclosed in Patent Documents 1 and 2, a concave-convex shape was formed in a resin layer on a substrate, the resin layer was cured, and then a conductor was provided to form a conductive pattern, so there was room for improvement in the adhesion of the conductor.

[0007] The inventors have conducted extensive research into improving the adhesion of conductors and have discovered that the adhesion of conductors to resin layers can be improved by placing a conductive composition on a resin layer before the resin layer is completely cured, and then pressurizing the conductive composition to obtain a conductor, thereby completing the present invention. [Means for solving the problem]

[0008] According to the present invention, the following techniques are provided.

[0009] [1] A step of forming a curable resin layer on a substrate; forming a recess on a surface of the curable resin layer opposite to the substrate; disposing a conductive composition containing conductive particles in the recess; a step of curing the curable resin layer; pressing the conductive composition to form a conductor; A method for producing a conductive substrate, comprising: [2] A method for producing the conductive substrate according to [1], In the step of forming the recess, forming the recesses on the surface of the curable resin layer by one or more methods selected from nanoimprinting, mechanical polishing, sandblast polishing, laser etching, and chemical etching; A method for manufacturing a conductive substrate, wherein in the step of disposing the conductive composition, the conductive composition is disposed in the recess and in an area on the surface of the curable resin layer excluding the recess. [3] A method for producing the conductive substrate according to [1], In the step of forming the recess, pressing an imprint plate having a temporary pattern against the surface of the curable resin layer to form the recess; The method for manufacturing a conductive substrate, wherein the conductor has a conductive pattern corresponding to the temporary pattern. [4] A method for producing the conductive substrate according to [3], The imprint plate has a concave-convex shape with an average pitch of 10 to 1000 μm. [5] A method for producing the conductive substrate according to [3] or [4], A method for manufacturing a conductive substrate, wherein in the step of placing a conductive composition containing conductive particles in the recesses, the recesses are filled with the conductive composition using a mask. [6] A method for producing a conductive substrate according to any one of [1] to [5], In the step of forming the recess, the curable resin layer is in a semi-cured state. [7] A method for producing a conductive substrate according to any one of [1] to [6], The particle diameter D at which the cumulative frequency is 50% in a volume-based cumulative particle diameter distribution curve obtained when the particle diameter of the conductive particles is measured by a laser diffraction scattering method 50 is 0.5 to 100 μm. [8] A method for producing a conductive substrate according to any one of [1] to [7], the curable resin layer contains a photocurable resin, The method for producing a conductive substrate, wherein ultraviolet irradiation is performed in the step of curing the curable resin layer. [9] A method for producing the conductive substrate according to [8], The method for producing a conductive substrate, wherein ultraviolet light is irradiated from the substrate side in the step of curing the curable resin layer.

[10] A method for producing a conductive substrate according to any one of [1] to [9], After the step of curing the curable resin layer, The method for producing a conductive substrate further comprises a step of infiltrating the conductive particles with component X to remove an oxide film on the surface of the conductive particles.

[11] A method for producing the conductive substrate according to

[10] , A method for producing a conductive substrate, wherein the component X includes at least one selected from the group consisting of an organic acid, a phosphorus oxoacid, and hydrazine or a derivative thereof.

[12] A method for producing a conductive substrate according to any one of [1] to

[11] , The method for producing a conductive substrate, wherein in the step of forming the conductor, the conductive composition is pressurized while being heated.

[13] A method for producing a conductive substrate according to any one of [1] to

[12] , A method for manufacturing a conductive substrate, wherein in the step of forming the conductor, the upper surface of the conductive composition is covered with a member and then pressed.

[14] A method for producing a conductive substrate according to any one of [1] to

[13] , The method for producing a conductive substrate, wherein the conductive composition contains one or both of a resin and a binder.

[15] A method for producing a conductive substrate according to any one of [1] to

[13] , The method for producing a conductive substrate, wherein the conductive composition is substantially free of resin and binder.

[16] A method for producing a conductive substrate according to any one of [1] to

[15] , The method for producing a conductive substrate, wherein the substrate is flexible.

[17] A method for producing a conductive substrate according to any one of [1] to

[16] , The method for producing a conductive substrate, wherein the substrate has optical transparency.

[18] A method for producing a conductive substrate according to any one of [1] to

[17] , The method for producing a conductive substrate, wherein the substrate is one or more materials selected from the group consisting of polyester, polyolefin, polyimide, polycarbonate, and paper.

[19] A method for producing a conductive substrate according to any one of [1] to

[18] , The method for manufacturing a conductive substrate, wherein the conductor has a conductive pattern.

[20] A method for producing an electronic device, comprising producing an electronic device using a conductive substrate obtained by the method for producing a conductive substrate according to any one of [1] to

[19] .

[21] A method for producing the electronic device according to

[20] , The method for manufacturing an electronic device, wherein the electronic device is an RF tag.

[22] A method for producing an electromagnetic wave shielding film, comprising producing an electromagnetic wave shielding film using a conductive substrate obtained by the method for producing a conductive substrate according to any one of [1] to

[18] .

[23] A method for producing a sheet heating element, comprising producing a sheet heating element using a conductive substrate obtained by the method for producing a conductive substrate according to any one of [1] to

[18] . [Effects of the Invention]

[0010] According to the present invention, a method for producing a conductor substrate that can improve the adhesion of a conductor can be provided. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a diagram illustrating a method for producing a conductive substrate according to the first embodiment. [Figure 2] FIG. 10 is a diagram illustrating a method for producing a conductive substrate according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings, similar components are denoted by similar reference numerals and descriptions thereof will be omitted where appropriate. To avoid complexity, (i) when there are multiple identical components in the same drawing, only one of them is given a symbol, and not all of them, or (ii) particularly in Figure 2 and subsequent figures, components similar to those in Figure 1 are not given a symbol again. All drawings are for illustrative purposes only, and the shapes and dimensional ratios of the components in the drawings do not necessarily correspond to the actual products.

[0013] In this specification, unless otherwise specified, the expression "X to Y" in the description of a numerical range means at least X and at most Y. For example, "1 to 5% by mass" means "at least 1% by mass and at most 5% by mass."

[0014] In the description of groups (atomic groups) in this specification, when a notation does not specify whether the group is substituted or unsubstituted, it encompasses both groups having no substituents and groups having a substituent. For example, the term "alkyl group" encompasses not only alkyl groups having no substituents (unsubstituted alkyl groups) but also alkyl groups having a substituent (substituted alkyl groups). In this specification, the term "(meth)acrylic" represents a concept that encompasses both acrylic and methacrylic. The same applies to similar terms such as "(meth)acrylate." Unless otherwise specified, the term "organic group" as used herein means an atomic group obtained by removing one or more hydrogen atoms from an organic compound. For example, a "monovalent organic group" refers to an atomic group obtained by removing one hydrogen atom from any organic compound. In this specification, the term "electronic device" is used to encompass elements, devices, final products, etc. to which electronic engineering technology is applied, such as semiconductor chips, semiconductor elements, printed wiring boards, electric circuit display devices, information and communication terminals, light-emitting diodes, physical batteries, and chemical batteries.

[0015] First Embodiment An example of a method for producing the conductive substrate 10 in the first embodiment will be described below with reference to Fig. 1. Fig. 1 and Fig. 2, which will be described later, are schematic diagrams showing cross sections of the conductive substrate 10 and the conductive substrate 20 when viewed from the front. Specifically, the cross sections refer to cross sections in a direction perpendicular to the direction in which the conductive pattern (conductor 5) extends when the conductive substrate 10 and the conductive substrate 20 are viewed in plan. In addition, in the plan view of the conductive substrate 10 and the conductive substrate 20, the conductive pattern corresponds to the circuit pattern. In the first embodiment, an example including a step of permeating component X is described, but the step may be performed arbitrarily, and the order of steps is not limited to this.

[0016] The method for producing the conductive substrate 10 in the first embodiment includes the following steps: A step of forming a curable resin layer 2 on a substrate 1; forming recesses 31 on the surface of the curable resin layer 2 opposite to the substrate 1 side; A step of placing a conductive composition 4 containing conductive particles in the recess 31; a step of curing the curable resin layer 2; a step of penetrating component X to remove an oxide film on the surface of the conductive particles; and b. pressing the conductive composition 4 to form a conductor 5, in this order.

[0017] Furthermore, the method for producing the conductive substrate 10 of the first embodiment includes the steps of: In the step of forming the recess 31, forming recesses 31 on the surface of the curable resin layer 2 by one or more methods selected from nanoimprinting, mechanical polishing, sandblast polishing, laser etching, and chemical etching; In the step of disposing the conductive composition 4, the conductive composition 4 is disposed in the recesses 31 and in the area on the surface of the curable resin layer 2 excluding the recesses 31.

[0018] This improves the adhesion of the conductor 5 to the curable resin layer 2. In other words, in this embodiment, the conductive composition 4 is disposed before the curable resin layer 2 is completely cured, and therefore, in order to obtain the conductor 5, a portion of the conductive composition 4 permeates the curable resin layer 2, or a portion of the curable resin layer 2 permeates into the gaps between the conductive particles of the conductive composition 4, and it is therefore thought that this can improve the adhesion between the subsequently obtained conductor 5 and the curable resin layer 2. Furthermore, it is believed that the conductive particles are sintered by applying pressure to the conductive composition, which improves the conductivity of the conductor 5.

[0019] Each step will be described in detail below.

[0020] [Step of forming curable resin layer 2] First, a curable resin layer 2 is formed on a substrate 1. In this embodiment, the curable resin layer 2 is formed on one surface of the substrate 1, as shown in Fig. 1A.

[0021] (Base material 1) The substrate 1 is usually in the form of a film, sheet or plate, and from the viewpoint of industrial productivity, the shape of the substrate 1 is preferably any of these. The substrate 1 is preferably flexible. By employing a flexible substrate 1, a flexible printed circuit (FPC) can be manufactured. By using a flexible substrate 1, it becomes easier to apply pressure using a "roll" in the "process of forming a conductor" described later. This is preferable from the viewpoint of mass production. Just to be clear, the substrate 1 may be a rigid substrate that does not have flexibility.

[0022] The substrate 1 preferably has optical transparency (transparency). This allows light such as ultraviolet light to be irradiated from the substrate 2 side during photo-curing of the curable resin layer 2, which will be described later. It also facilitates uniform curing of the entire curable resin layer 2. That is, when light is irradiated directly onto the curable resin layer 2, the light is blocked from the area on the curable resin layer 2 where the conductive composition 4 is provided, making it difficult to cure. However, by irradiating light from the side opposite the curable resin layer 2, i.e., from the substrate 2 side, it is possible to irradiate the entire curable resin layer 2 with light, facilitating uniform curing.

[0023] Although a general resin film can be used for the substrate 1, in consideration of cost and end use, it is preferable that the substrate 1 be at least one selected from the group consisting of polyesters such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate), polyolefins such as polyethylene and polypropylene, polycarbonate, polyimide, and paper. The paper may be coated paper (paper whose surface is coated with a coating agent) or ordinary uncoated paper. Among these, polyester and polyolefin are preferred for the substrate 1 in order to obtain good transparency during photocuring of the curable resin layer 2 described below. Furthermore, in this embodiment, a conductive pattern with sufficiently low resistivity can be obtained without heating or by heating at a relatively low temperature in the "step of forming the conductor 5." Therefore, a substrate 1 with low heat resistance, such as polyester, polyolefin, or paper, can be used. On the other hand, when a substrate 1 with high heat resistance, such as polyimide, is used, high-temperature heating can be performed in the "step of forming the conductor 5," and the resistivity of the resulting conductive pattern can be further reduced.

[0024] (Curing resin layer 2) The curable resin layer 2 is formed on the substrate 1 and can bond the substrate 1 to a conductor 5 described below. The curable resin layer 2 is formed using a resin material. The formation method is not particularly limited, and any known method for forming a resin film can be used. The resin material may contain a known solvent when forming the curable resin layer 2. If a solvent is contained, it is desirable to dry the solvent before curing, as described below. The curable resin layer 2 is formed using a resin material, preferably a thermosetting or photocurable resin material. If the substrate 1 is light-transmitting, the curable resin layer 2 can be made photocurable, so that the curable resin layer 2 can be cured by irradiating light from the substrate 1 side. If the substrate 1 is not light-transmitting, the curable resin layer 2 can be made thermosetting, so that the curable resin layer 2 can be cured by heating. Just to be clear, the curable resin layer 2 may have both thermosetting and photosetting properties, or may have only one of thermosetting and photosetting properties.

[0025] Examples of materials constituting the curable resin layer 2 include various thermosetting or photocurable resin materials, or resin materials that have both thermosetting and photocurable properties.Specific examples include thermosetting or photocurable resin materials such as epoxy resin-containing materials, polymerizable (meth)acrylate-containing materials, urethane-based materials, urethane (meth)acrylate-containing materials, and silicone-based materials. The curable resin layer 2 can also be made of a commercially available product. For example, the curable resin layer 2 can be made of various thermosetting or photocurable resin materials that are known or commercially available as hard coating agents. In addition, various thermosetting or photocurable resin materials that are known or commercially available as primers can also be used.

[0026] When the curable resin layer 2 is thermosetting, it is preferable to form the curable resin layer 2 so that the thermosetting proceeds at a heating temperature that does not damage the substrate 1. For example, when the substrate 1 is made of a resin, it is preferable to design the curable resin layer 2 so that the curing reaction proceeds sufficiently when heated at a temperature lower than the glass transition temperature of the resin.

[0027] 1B, the curable resin layer 2 is preferably in an uncured or semi-cured state, and more preferably in a semi-cured state, in order to maintain the shape of the recesses 31 when the conductive composition 4 is disposed. The fact that the curable resin layer 2 is in an uncured or semi-cured state is believed to enable a portion of the curable resin layer 2 to penetrate into the gaps between the conductive particles in the "step of disposing the conductive composition 4" described below. This is believed to contribute to further improving the adhesion of the final conductive pattern.

[0028] The thickness of the curable resin layer 2 is not particularly limited, but is preferably 1 to 30 μm, more preferably 5 to 15 μm, in order to obtain sufficient adhesiveness.

[0029] In this embodiment, the curable resin layer 2 is described as being a single layer, but the curable resin layer 2 may be a single layer or two or more layers. For example, if the substrate 1 is paper, a two-layer curable resin layer 2 may be used in consideration of penetration into the fibrous paper. In this case, the first adhesive layer closest to the paper plays a role of "sealing."

[0030] [Step of forming recess 31] Next, recesses 31 are formed on the surface of the curable resin layer 2 opposite to the substrate 1 side. The recesses 31 are depressions or irregularities in the flat surface of the curable resin layer 2 on the side opposite to the substrate 1. In the first embodiment, the recesses 31 are preferably formed on the surface of the substrate 1 so that irregularities are obtained over at least the entire region where the conductive composition 4 described below is disposed. The shape, size, and number of the recesses 31 are not particularly limited and are set appropriately depending on the application of the conductive substrate 10. In the first embodiment, the recesses 31 are typically obtained by a surface roughening treatment described later, and may have a maximum depth of less than 3 μm from the standpoint of ease of filling with the conductive composition, but are not limited to this.

[0031] The recesses 31 are formed on the surface of the curable resin layer 2 by one or more methods selected from nanoimprinting, mechanical polishing, sandblasting, laser etching, and chemical etching. That is, the recesses 31 are obtained by roughening the surface of the curable resin layer 2. This improves adhesion to the conductive composition 4 described below. Among these, nanoimprinting, laser etching, and chemical etching are preferred because they allow for easy control of the concavo-convex pattern and the desired adhesion to be achieved.

[0032] 1B, in this embodiment, a plurality of recesses 31 are formed on the surface of the curable resin layer 2 by nanoimprinting using a nanoimprinting plate 61. That is, by pressing the finely textured surface of the nanoimprinting plate 61 against the curable resin layer 2, the finely textured surface is transferred to the curable resin layer 2, thereby forming the recesses 31.

[0033] [Step of placing conductive composition 4] Next, a conductive composition 4 containing conductive particles is placed in the recess 31. Here, placing the conductive composition 4 means embedding or filling the conductive composition 4, and coating or spreading the conductive composition 4. In this embodiment, as shown in FIG. 1C, by placing a conductive composition 4 on the surface of the curable resin layer 2 having the recess 31, the conductive composition 4 can be filled inside the recess 31 while the area on the surface of the curable resin layer 2 having the recess 31 other than the recess 31 can be covered with the conductive composition 4. Specifically, the conductive particle-containing layer 4 may be provided over the entire surface of the substrate 1, or may be provided only on a portion of the substrate 1. In the former case, the conductive particle-containing layer 4 can be formed by coating using a device such as a blade coater, air knife coater, doctor coater, roll coater, bar coater (rod coater), or curtain coater. In the latter case, the conductive particle-containing layer 4 can be formed by various printing methods, such as screen printing, dispense printing, gravure printing, letterpress printing, lithographic printing (offset printing), inkjet printing, and transfer printing. By appropriately designing the "pattern" during printing, it is possible to produce a substrate with a pattern structure, such as a conductive film (circuit pattern) that can function as a circuit or a mesh pattern with electromagnetic wave shielding properties. When the conductive composition is provided only on a portion of the substrate 1, it is preferable that the printing "pattern" be appropriately designed depending on the intended use of the final conductive substrate 10. To prevent the conductive particle-containing layer 4 from being formed in any location other than the desired location on the substrate 1, for example, a film with holes cut out therein may be placed on the substrate 1, the conductive composition may be applied or printed on top of the film, and then the film may be removed.

[0034] When the conductive composition 4 is applied or coated, it is preferable to apply it so that the film thickness is, for example, preferably 0.5 to 100 μm, more preferably 5 to 60 μm, and even more preferably 10 to 40 μm. By setting the film thickness to be equal to or greater than the above lower limit, the conductivity of the final conductive pattern can be improved. On the other hand, by setting the film thickness to be equal to or less than the above upper limit, the entire conductive substrate 10 having the final conductive pattern can be made thinner. This is preferable, for example, from the viewpoint of miniaturization and weight reduction of electronic devices.

[0035] (Conductive composition 4) The conductive composition 4 is preferably in a paste state at room temperature for ease of placement.

[0036] From the viewpoint of further increasing the conductivity of the finally obtained conductive pattern, the amount of the resin component in the conductive composition 4 is preferably 15 parts by mass or less, i.e., 0 to 15 parts by mass, more preferably 0 to 10 parts by mass, and even more preferably 0 to 5 parts by mass, per 100 parts by mass of the conductive particles. The remaining component in the conductive composition 4 is preferably conductive particles. If there is no problem with the pattern formability, the conductive composition 4 does not need to contain a resin component. From the viewpoint of improving the conductivity, it is preferable that the conductive composition 4 does not substantially contain a curable component as a component other than the conductive particles. On the other hand, from the viewpoint of improving the pattern formability, i.e., the printability and coatability of the conductive composition, the conductive composition 4 may contain a resin component such as a resin or a binder. From the viewpoint of fully obtaining the effect of using the resin component, the amount of the resin component in the conductive composition 4 is preferably 1 to 15 parts by mass, more preferably 1 to 10 parts by mass, and even more preferably 1 to 5 parts by mass, per 100 parts by mass of the conductive particles. The remaining component in the conductive composition 4 is preferably conductive particles.

[0037] Specific examples of resin components that can be contained in the conductive composition 4 preferably include polyvinylpyrrolidone, polyester, epoxy resin, (meth)acrylic resin, polyvinyl acetal, cellulose resin (such as ethyl cellulose), and phenol resin.

[0038] The conductive composition 4 may contain a solvent. When the conductive composition 4 contains a solvent, the filling property and application property of the conductive composition 4 are improved. The solvent typically contains an organic solvent. The solvent may contain water as long as the conductive particles can be appropriately dispersed in the solvent. The type of solvent is not particularly limited. Any solvent may be used as long as it does not substantially alter the components in the conductive composition 4. The amount of solvent used may be adjusted appropriately depending on the coating / printing method of the conductive composition 4. The amount of solvent used is, for example, 3 to 30 mass %, preferably 5 to 25 mass %, and more preferably 10 to 20 mass % of the total amount of the conductive composition 4.

[0039] The conductive particles contained in the conductive composition 4 preferably contain at least one element selected from the group consisting of silver and copper, from the viewpoints of availability and good conductivity. Specifically, the conductive particles preferably include at least one selected from the group consisting of particles primarily composed of silver and particles primarily composed of copper. Here, the expression "primarily composed of silver" means that the ratio of silver element to all constituent elements in the particles is preferably 50 mol% or more, more preferably 75 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more. Similarly, the expression "primarily composed of copper" means that the ratio of copper element to all constituent elements in the particles is preferably 50 mol% or more, more preferably 75 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more. It should be noted that the conductive particles may contain elements other than silver and copper, such as gold, aluminum, platinum, palladium, iridium, tungsten, nickel, tantalum, lead, and zinc, as long as the desired conductivity is achieved.

[0040] The conductive particles may contain two or more elements. For example, conductive particles in which the surfaces of copper particles are silver-plated (silver-coated copper particles) are preferably used in this embodiment. Silver-coated copper particles are particles whose main component is copper, and the surfaces of the copper particles are plated with silver in an amount of up to 35 mass% based on the total mass of the particles, for example.

[0041] Median diameter D of conductive particles 50 is preferably 0.5 to 100 μm, more preferably 0.6 to 50 μm, even more preferably 0.7 to 30 μm, and particularly preferably 0.7 to 20 μm. D 50 By making the value of the particle diameter equal to or larger than the lower limit, the number of grain boundaries between conductive particles per unit volume can be reduced, which is believed to lead to a further reduction in the resistivity of the resulting conductive pattern. D 50By making the value of the conductive particles equal to or less than the upper limit, the "gaps" between the conductive particles are reduced, which is thought to lead to a smaller specific resistance of the resulting conductive pattern. By the way, D 50 It is considered that when D is an appropriate value, a part of the curable resin layer 2 easily penetrates into the gaps between the conductive particles in the temporary pattern. 50 It is believed that an appropriate value of ρ also contributes to further improving adhesion. With nano-sized conductive particles, it is unlikely that the curable resin layer 2 will penetrate into the gaps between the conductive particles.

[0042] The median diameter D 50 means the particle size at which the cumulative frequency is 50% in the volume-based cumulative particle size distribution curve obtained when particle sizes are measured by a laser diffraction scattering method.

[0043] Conductive particles can be purchased from, for example, DOWA Electronics Co., Ltd., Fukuda Metal Foil and Powder Co., Ltd. Two or more different conductive particles may be mixed together for the purpose of adjusting or optimizing the particle size distribution or for other purposes.

[0044] From the viewpoint of further reducing the resistivity of the final conductive pattern, it is preferable that the proportion of conductive particles in the conductive composition 4 is high. Specifically, the proportion of conductive particles in the total non-volatile components of the conductive composition 4 is preferably 95% by mass or more, more preferably 97% by mass or more, even more preferably 98% by mass or more, and particularly preferably 99% by mass or more. In other words, from the viewpoint of further reducing the resistivity of the resulting conductive pattern, it is preferable that the conductive composition 4 is substantially free of resin components such as resins and binders. Here, "substantially free of" resin components means that the composition is completely free of resin components, or that the amount of resin components contained is so small that the expected effect of using the resin components cannot be obtained (for example, 1% by mass or less, specifically 0.5% by mass or less, of the total non-volatile components of the conductive composition 4). The conductive composition 4 does not need to contain resins or binders as long as the desired conductive pattern can be obtained.

[0045] The conductive composition 4 may or may not contain various additive components found in conventional ink compositions and conductive pastes.

[0046] It is preferable that the conductive particles are not substantially sintered. In this embodiment, the conductive particles are usually sintered in the "step of forming the conductor 5" described later.

[0047] [Step of curing the curable resin layer 2] Next, the curable resin layer 2 is cured. The curable resin layer 2 can be cured by light such as ultraviolet light if the curable resin layer 2 is photocurable, or by heating if the curable resin layer 2 is thermosetting. Furthermore, when the substrate 1 is transparent, the curable resin layer 2 can be cured by irradiating it with ultraviolet (UV) light from the substrate 1 side. This also facilitates uniform curing of the entire curable resin layer 2. That is, when light is irradiated directly onto the curable resin layer 2, the area on the curable resin layer 2 where the conductive composition 4 is provided is blocked from the light and is difficult to cure. However, by irradiating light from the side opposite the curable resin layer 2, i.e., from the substrate 2 side, the entire curable resin layer 2 can be irradiated with light, facilitating uniform curing. The conditions for light irradiation and heating may be adjusted and optimized as appropriate depending on the specific material that constitutes the curable resin layer 2. However, when curing the curable resin layer 2 by heating, care must be taken to prevent the substrate 1 from being damaged by heat.

[0048] The curing may be complete curing, or may be limited to a certain degree and not complete curing, as long as sufficient adhesion is obtained.

[0049] When the resin material constituting the curable resin layer 2 contains a solvent, a step of volatilizing the solvent may be further included before curing the curable resin layer 2. Examples of methods for volatilizing the solvent include hot air drying, heating, and light irradiation.

[0050] For example, when volatilizing the solvent on the substrate 1, heating can be performed using a heater provided on the substrate 1 or a heater provided outside the substrate 1. The conditions for the heat treatment are not particularly limited as long as the solvent is sufficiently dried, but are adjusted from the viewpoints of sufficiently drying the solvent and preventing deterioration of the substrate 1 due to excessive heating. The temperature for the heat treatment is preferably 50 to 150°C, more preferably 80 to 120°C. The time for the heat treatment is preferably 1 to 60 minutes, more preferably 3 to 30 minutes.

[0051] [Step for allowing ingredient X to penetrate] Furthermore, in this embodiment, a component X for removing oxide films on the surfaces of the conductive particles may be further impregnated into the filled conductive composition 4. This facilitates sintering of the conductive particles in the "step of forming a conductor 5" described below, and tends to further increase the conductivity of the finally obtained conductive pattern.

[0052] It is preferable that component X penetrates into the conductive composition 4 through the gaps between the conductive particles. This tends to further increase the conductivity of the final conductive pattern. For this reason, this "step of penetrating component X" may be carried out simultaneously with the "step of forming conductor 5" described below.

[0053] 1D, this can be achieved by dropping or spraying a liquid 7 containing a component X capable of removing an oxide film on the surface of the conductive particles, thereby contacting and preferably penetrating the conductive composition 4. Specifically, for example, the liquid 7 can be dropped and penetrated using an inkjet method or a dispenser method.

[0054] The liquid 7 containing component X is preferably water in which component X is dissolved or dispersed. The use of water is preferable from the viewpoints of reducing the environmental load and process safety (non-flammability). Of course, an organic solvent in which component X is dissolved or dispersed can also be used. Instead of using a liquid 7 containing component X, component X in a gaseous state may be used. It is also possible to bring a sheet containing component X into contact with the conductive composition 4, preferably by applying pressure, to allow component X to penetrate. Specific examples of the sheet include paper or nonwoven fabric containing component X, and resin sheets having component X coated or printed on their surfaces.

[0055] Component X is not particularly limited as long as it is capable of removing the oxide film on the surface of the conductive particles. In this specification, "removal" of an oxide film includes not only the removal of the oxide itself present on the surface of a conductive particle, but also the case where the oxide undergoes a chemical change such as reduction, causing the oxide to return to a non-oxide state.

[0056] According to the inventors' findings, component X preferably contains at least one selected from the group consisting of organic acids, phosphorus oxoacids, and hydrazine or its derivatives, which are particularly suitable when the conductive particles contain copper or silver.

[0057] Examples of organic acids include carboxylic acids such as citric acid, formic acid, acetic acid, malonic acid, malic acid, tartaric acid, ascorbic acid, succinic acid, fumaric acid, and propionic acid. Specific examples of phosphorus oxoacids include phosphinic acid, phosphonic acid, diphosphorous acid, triphosphoric acid, and metatriphosphoric acid. Of these, phosphinic acid is particularly preferred. Examples of hydrazine or its derivatives include hydrazine itself; hydrazine salts such as hydrazine monohydrochloride, hydrazine dihydrochloride, hydrazine monohydrobromide, and hydrazine sulfate; and other compounds having an -NH-NH2 structure.

[0058] Additionally, from the viewpoint of removing an oxide film, a compound having a small pKa in water can be used as component X. Specifically, a compound having a pKa in water of -5.0 to 5.0 is preferred as component X, and a compound having a pKa of -4.0 to 4.5 is more preferred as component X. Incidentally, when component X is a polybasic acid, it is preferred that the smallest pKa among the multiple pKas is within the above range. Considering only the small pKa and the resulting ability to remove oxide films, it is conceivable to use an inorganic acid such as hydrochloric acid, nitric acid, or sulfuric acid as component X. However, in consideration of problems that may occur if the acid remains in the conductor 5, an organic acid is preferred as component X. The pKa value used here can be the value at room temperature (e.g., 25°C). However, from the viewpoint of the removability of the oxide film in the actual process, it can be said that it is preferable to use the pKa value at the temperature in the "step of forming the conductor 5."

[0059] Additionally, any compound capable of returning an oxide film to a non-oxidized state by a reduction reaction can also be used as component X. For example, a compound having an aldehyde group can be used as component X because it may be able to reduce an oxide.

[0060] Furthermore, compounds that have a small pKa in water and can return an oxidized film to a non-oxidized state through a reduction reaction are also preferably used as component X. An example of such a compound is formic acid. Formic acid has the advantage that it is easily volatile and therefore does not easily remain in the pattern.

[0061] In addition to the above, examples of component X include pyrogallol, phenidone, hydroquinone, and orthoaminophenol, which are known to function as reducing agents in the field of silver halide photography. When a conductive pattern having a lower resistivity is obtained when a certain compound is infiltrated into the conductive composition 4 compared to when the compound is not infiltrated, the compound can be used as component X.

[0062] When a liquid in which component X is dissolved or dispersed is brought into contact with the conductive composition 4, the concentration of component X in the liquid may be adjusted as appropriate. The concentration may be adjusted from the viewpoints of allowing a sufficient amount of component X to penetrate into the conductive composition 4 and reducing the amount of residual component X to suppress corrosion or deterioration of the conductive pattern. The concentration of component X in the liquid is, for example, 0.05 to 50 mol / L, preferably 0.1 to 40 mol / L, more preferably 0.1 to 30 mol / L, even more preferably 0.1 to 10 mol / L, and particularly preferably 0.15 to 5.0 mol / L. Of course, a liquid containing component X at a concentration lower than the concentrations shown here may be used, or a liquid containing component X at a concentration higher than the concentrations shown here (for example, saturation concentration) may be used.

[0063] [Step of Pressurizing the Conductive Composition 4 to Form the Conductor 5] Next, the conductive composition 4 is pressurized to form the conductor 5. This can increase the conductivity of the conductor 5. Preferably, the conductive particles in the conductive composition 4 are sintered by the pressure.

[0064] 1E, the pressure is preferably applied after covering the exposed surface of the conductive composition 4 with a member 8. In addition, as one example, the pressure can be applied by sandwiching a laminate of the substrate 1, the curable resin layer 2, the conductive composition 4, and the member 8 between two opposing rolls 9a and 9b and transporting the laminate between the two rolls. The member 8 is preferably a film-like material. In this embodiment, a liquid 7 containing component X is present above the conductive composition 4. In this case, it is believed that component X penetrates into the conductive composition 4 by pressurization, removing the oxide film on the conductive particles and simultaneously promoting sintering of the conductive particles.

[0065] There are several advantages to using the member 8 when applying pressure. Examples of the advantages include the following: Damage to the roll 9a can be suppressed. In addition, it may be possible to suppress the conductive composition 4 from being partially or entirely peeled off and adhering to the roll 9a. Since the roll 9a is prevented from coming into direct contact with the conductive composition 4, unintended deformation or collapse of the conductive composition 4 can be easily prevented. The member 8 functions as a buffer, making it easier to apply pressure uniformly to the conductive composition 4. This leads to, for example, an improvement in the yield of the final conductive substrate 10. Furthermore, when infiltration of component X and pressurization are performed simultaneously, applying pressure uniformly to the conductive composition 4 is also preferable because it leads to uniform infiltration of component X into the conductive composition 4.

[0066] From one viewpoint, the material of the member 8 can be the same as that of the base material 1. That is, the member 8 can be preferably a polyester film such as a PET film. From another viewpoint, in order to prevent damage to the conductive composition 4, an easily peelable film or release paper can be preferably used as the member 8. From another perspective, the member 8 may be made of a non-resin material such as aluminum foil.

[0067] On the other hand, in order to simplify the manufacturing process by reducing the amount of process materials and reduce waste, pressurization may be performed without using the member 8.

[0068] 1E shows an embodiment in which the conductive composition 4 is pressed by two opposing rolls 9a and 9b. However, the conductive composition 4 may be pressed by other methods. As one example, the laminate of the substrate 1, the curable resin layer 2, the conductive composition 4, and the member 8 may be sandwiched between two flat plates and pressed (flat press). As another example, the laminate of the substrate 1, the curable resin layer 2, the conductive composition 4, and the member 8 may be placed on a flat plate, and a roll may be applied from above, and the conductive composition 4 may be pressed while rolling. As yet another example, a method may be considered in which a roll is applied from below the substrate 1, the curable resin layer 2, the conductive composition 4, and the member 8, and the conductive composition 4 may be pressed while rolling.

[0069] The pressure application is preferably carried out while heating the conductive composition 4. This tends to improve the conductivity of the conductive pattern. Preferably, the conductive composition 4 is pressed at a pressure of 1 to 5000 MPa and heated at a temperature of 50 to 400°C. More preferably, the conductive composition 4 is pressed at a pressure of 30 to 1000 MPa and heated at a temperature of 70 to 200°C. Even more preferably, the conductive composition 4 is pressed at a pressure of 50 to 300 MPa and heated at a temperature of 80 to 150°C. As shown in FIG. 1E, when pressure is applied using two opposing rolls 9a and 9b, it is preferable to use rolls with built-in heaters that can adjust the temperature.

[0070] [Other optional processes] The method for producing the conductive substrate of this embodiment may include steps other than the steps described above. One example is a step of removing component X remaining on the surface or inside the obtained conductive pattern after pressing. Specific examples include a step of immersing the obtained conductive substrate 10 in a liquid (water or an organic solvent) that can dissolve or disperse component X, or a step of pouring a liquid (water or an organic solvent) onto the surface of the conductive pattern to wash away the remaining component X. Another possible step is to vaporize and remove the remaining component X by heating the obtained conductive substrate 10 at a temperature that does not damage the substrate 1.

[0071] Second Embodiment Next, a method for producing the conductive substrate 20 according to the second embodiment will be described with reference to FIG. In the first embodiment, a case where recesses 31 are formed on the surface of the curable resin layer 2 by one or more methods selected from nanoimprinting, mechanical polishing, sandblast polishing, laser etching, and chemical etching is described, but in the second embodiment, a case where recesses 32 are formed by pressing an imprint plate 62 having a temporary pattern onto the surface of the curable resin layer 2 is described. Hereinafter, a description of the same configuration and effects as in the first embodiment will be omitted as appropriate.

[0072] In the manufacturing method of the conductive substrate 20 in the second embodiment, in the step of forming the recesses 32, an imprint plate 62 having a temporary pattern is pressed against the surface of the curable resin layer 2 to form the recesses 32, and the conductor 5 is configured to have a conductive pattern corresponding to the temporary pattern. In other words, since the recesses 32 have a pattern corresponding to the temporary pattern of the imprint plate 62, the conductor 5 obtained from the conductive composition 4 charged in the recesses 32 has a conductive pattern corresponding to the temporary pattern. In the second embodiment, as in the first embodiment, the conductor 5 is obtained by disposing the conductive composition 4 before the curable resin layer 2 is completely cured. Therefore, a portion of the conductive composition 4 penetrates into the curable resin layer 2, or a portion of the curable resin layer 2 penetrates into the gaps between the conductive particles of the conductive composition 4, thereby improving the adhesion between the subsequently obtained conductor 5 and the curable resin layer 2.

[0073] A method for producing the conductive substrate 20 in the second embodiment will be described below.

[0074] First, in the same manner as in the first embodiment, a curable resin layer 2 is formed on a substrate 1 (FIG. 2A).

[0075] [Step of forming recess 32] 2B, the imprint plate 62 is pressed against the curable resin layer 2 provided on the surface of the substrate 1 to form recesses 32. That is, the temporary pattern of the imprint plate 62 is transferred to the surface of the curable resin layer 2, and recesses 32 corresponding to the temporary pattern are formed. In order to obtain good recesses 32, it is preferable to press the imprinting plate 62 against the curable resin layer 2. Pressing may be performed using a roller or a flat plate press.

[0076] The imprint plate 62 is a known one used to form the recesses 32 in the curable resin layer 2 . The imprint plate 62 has a temporary pattern. The temporary pattern is formed by protrusions, and corresponds to the conductive pattern of the conductor 5 to be obtained later. That is, the protrusions having a desired pattern are pressed against the imprint plate 62 to form recesses 32 in the curable resin layer 2, and then the recesses 32 are filled with the conductive composition 4, thereby obtaining the desired conductive pattern. The method for forming the provisional pattern on the imprint plate 62 is not particularly limited, and any known method can be used. Furthermore, the provisional pattern of the imprint plate 62 and the conductive pattern of the conductor 5 do not necessarily have to match; for example, depending on processing and manufacturing conditions, there may be a difference in width when viewed in a plane, and there may be a difference in thickness and height when viewed in a cross-section.

[0077] Furthermore, the convex portions of the imprinting plate 62 are not particularly limited and can be designed appropriately according to the desired conductive pattern. For example, the imprinting plate 62 may have a concave-convex shape with an average pitch of 10 to 1000 μm. The average pitch of the imprinting plate 62 corresponds to the average value of the distance between adjacent conductors in the conductive pattern.

[0078] The shape, size, and number of the recesses 32 are not particularly limited and can be appropriately set according to a desired conductive pattern depending on the application of the conductive substrate 20. The recesses 32 may be continuous grooves. The depth of the recesses 32 is set appropriately depending on the thickness of the curable resin layer 2, and may be, for example, 40 to 80% or 50 to 70% of the thickness of the curable resin layer 2. Specifically, the depth of the recesses 32 may be, for example, 3 to 100 μm or 10 to 80 μm. The cross-sectional shape of the recess 32 is preferably inversely tapered in the direction away from the substrate 1. This is preferable because it makes it easier to fill the conductive particles without leaving any gaps. However, if the recess 32 is a continuous groove, the cross section is taken as a plane perpendicular to the direction in which the recess 32 continues.

[0079] [Step of placing conductive composition 4] Next, as shown in FIG. 2C , a conductive composition 4 is placed in the recesses 32. In the second embodiment, it is preferable to fill the conductive composition 4 only in the recesses 32. This makes it possible to easily obtain a desired conductive pattern corresponding to the recesses 32. That is, in this embodiment, since the recesses 32 correspond to the conductive pattern, the desired conductive pattern can be obtained by filling the recesses 32 with the conductive composition 4. Alternatively, a mask having openings corresponding to the recesses 32 may be used on the curable resin layer 2 to fill the recesses 32 with the conductive composition. This allows the conductive composition 4 to be filled only within the recesses 32, and eliminates the need for a step of removing the conductive composition that has spilled out of the recesses 32.

[0080] (drying process) Furthermore, this process may include a drying step in which the conductive composition 4 filled in the recesses 32 is dried to remove the solvent in the conductive composition 4. This makes it easier for the component X (oxide film removal solution) to penetrate into the copper particles and shortens the sintering time in the subsequent pressure application step. Furthermore, when water is used as the solvent, dilution of the component X can be suppressed. The drying conditions are not particularly limited. The temperature and time may be selected so long as they do not damage or deteriorate the substrate.

[0081] 2D to 2E, the curable resin layer 2 is cured in the same manner as in the first embodiment, and then the component X for removing the oxide film on the surface of the conductive particles is impregnated into the filled conductive composition 4 to remove the oxide film, and then the conductive composition 4 is pressed to form the conductor 5, thereby obtaining the conductive substrate 20 of the second embodiment. In the second embodiment, the conductor 5 of the conductive substrate 20 has a conductive pattern corresponding to the temporary pattern of the imprint plate 62.

[0082] In addition, the method for manufacturing the conductive substrate 20 of the second embodiment can employ the same configuration as that described for the method for manufacturing the conductive substrate 10 of the first embodiment, and similar effects can be obtained.

[0083] <Electronic device manufacturing method> The conductive substrate 10 and conductive substrate 20 obtained as described above can be used to manufacture electronic devices.

[0084] Here, some examples of electronic devices will be described. However, it should be noted that the electronic devices including the conductive substrate 10 and the conductive substrate 20 obtained by the manufacturing method of this embodiment are not limited to these examples. Sensors: For example, the conductive substrate 10 and conductive substrate 20 obtained by the manufacturing method of this embodiment can be applied to conductive members / circuits in sensors such as pressure-sensitive sensors and vital sensors. Solar cells: For example, the conductive base material 10 and the conductive base material 20 obtained by the manufacturing method of this embodiment can be applied to current collecting wiring of solar cells. Membrane switch: A membrane switch is a thin sheet-like switch made by printing circuits and contacts on a film and then laminating the printed film. The manufacturing method of the conductive substrate 10 and the conductive substrate 20 of this embodiment can be applied to form the circuits and contacts. Touch sensor / touch panel: For example, the manufacturing method of the conductive substrate 10 and the conductive substrate 20 of the present embodiment can be applied to form lead wiring in a touch sensor / touch panel. It is also conceivable to apply the manufacturing method of the conductive substrate 10 and the conductive substrate 20 of the present embodiment to form transparent electrodes in a touch sensor / touch panel. Flexible substrate: Conventionally, a circuit is formed by first coating the entire surface of a flexible film with a metal film and then removing unnecessary portions of the metal film using chemicals. Instead of this conventional method, it is possible to form a circuit using the manufacturing method of the conductive substrate 10 and the conductive substrate 20 of this embodiment.

[0085] In particular, in electronic devices where circuits have conventionally been formed using conductive paste, by using the manufacturing method of this embodiment to form circuits, the resistivity of the circuits can be reduced, and improved performance of the electronic devices can be expected.

[0086] A particularly preferred example of the electronic device is an RF tag. That is, the method for producing a conductive substrate of this embodiment is preferably used to produce a conductive circuit such as an antenna portion of an RF tag. For the specific structure of the RF tag, reference can be made to, for example, Japanese Patent Application Laid-Open No. 2003-332714 and Japanese Patent Application Laid-Open No. 2020-46834.

[0087] <Method of manufacturing electromagnetic wave shielding film> As an application other than electronic devices, it is conceivable to manufacture an electromagnetic wave shielding film by the manufacturing method of the conductive substrate 10 and the conductive substrate 20 of the present embodiment. Specifically, in the lamination step, an electromagnetic wave shielding film can be manufactured by printing the conductive composition in a pattern specific to the electromagnetic wave shielding film (such as a mesh pattern).

[0088] <Method of manufacturing a sheet heating element> As another application, the method for manufacturing the conductive substrate 10 and the conductive substrate 20 according to the present embodiment may be used to manufacture a sheet heating element. A sheet heating element is an element that generates heat by passing an electric current through electrical wiring provided on a substrate. A specific example of a sheet heating element is a sheet heating element for preventing fogging or cold weather, such as on the rear window of a passenger vehicle.

[0089] <Conductive substrate 10 and article for manufacturing conductive substrate 20> For example, an article comprising a substrate 1, a curable resin layer 2 provided on the surface of the substrate 1, and a conductive composition 4 containing conductive particles arranged on the surface of the curable resin layer 2, as shown in Figure 2D, can be considered a "semi-finished product" for producing the conductive substrate 10 and the conductive substrate 20.

[0090] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. [Explanation of symbols]

[0091] 1 Base material 2 Curing resin layer 31 Recess 32 recess 4 Conductive composition 5 Conductors 61 Nanoimprint Plate 62 Imprint 7 liquid 8. Components 9a Roll 9b Roll 10 Conductive substrate 20 Conductive substrate

Claims

1. forming a curable resin layer on a substrate; forming a recess on a surface of the curable resin layer opposite to the substrate; disposing a conductive composition containing conductive particles in the recess; a step of curing the curable resin layer; pressing the conductive composition to form a conductor; A method for producing a conductive substrate, comprising:

2. A method for producing the conductive substrate according to claim 1, In the step of forming the recess, forming the recesses on the surface of the curable resin layer by one or more methods selected from nanoimprinting, mechanical polishing, sandblast polishing, laser etching, and chemical etching; A method for manufacturing a conductive substrate, wherein in the step of disposing the conductive composition, the conductive composition is disposed in the recess and in an area on the surface of the curable resin layer excluding the recess.

3. A method for producing the conductive substrate according to claim 1, In the step of forming the recess, pressing an imprint plate having a temporary pattern against the surface of the curable resin layer to form the recess; The method for manufacturing a conductive substrate, wherein the conductor has a conductive pattern corresponding to the temporary pattern.

4. The method for producing the conductive substrate according to claim 3, The imprint plate has a concave-convex shape with an average pitch of 10 to 1000 μm.

5. The method for producing the conductive substrate according to claim 3, A method for manufacturing a conductive substrate, wherein in the step of placing a conductive composition containing conductive particles in the recesses, the recesses are filled with the conductive composition using a mask.

6. A method for producing the conductive substrate according to any one of claims 1 to 5, In the step of forming the recess, the curable resin layer is in a semi-cured state.

7. A method for producing the conductive substrate according to any one of claims 1 to 5, The particle diameter D at which the cumulative frequency reaches 50% in a volume-based cumulative particle diameter distribution curve obtained when the particle diameter of the conductive particles is measured by a laser diffraction scattering method. ５０ is 0.5 to 100 μm.

8. A method for producing the conductive substrate according to any one of claims 1 to 5, the curable resin layer contains a photocurable resin, The method for producing a conductive substrate, wherein ultraviolet irradiation is performed in the step of curing the curable resin layer.

9. The method for producing a conductive substrate according to claim 8, The method for producing a conductive substrate, wherein ultraviolet light is irradiated from the substrate side in the step of curing the curable resin layer.

10. A method for producing the conductive substrate according to any one of claims 1 to 5, After the step of curing the curable resin layer, The method for producing a conductive substrate further comprises a step of infiltrating the conductive particles with component X to remove an oxide film on the surface of the conductive particles.

11. The method for producing a conductive substrate according to claim 10, A method for producing a conductive substrate, wherein the component X includes at least one selected from the group consisting of an organic acid, a phosphorus oxoacid, and hydrazine or a derivative thereof.

12. A method for producing the conductive substrate according to claim 1 or 2, The method for producing a conductive substrate, wherein in the step of forming the conductor, the conductive composition is pressurized while being heated.

13. A method for producing the conductive substrate according to claim 1 or 2, A method for manufacturing a conductive substrate, wherein in the step of forming the conductor, the upper surface of the conductive composition is covered with a member and then pressed.

14. A method for producing the conductive substrate according to claim 1 or 2, The method for producing a conductive substrate, wherein the conductive composition contains one or both of a resin and a binder.

15. A method for producing the conductive substrate according to claim 1 or 2, The method for producing a conductive substrate, wherein the conductive composition is substantially free of resin and binder.

16. A method for producing the conductive substrate according to claim 1 or 2, The method for producing a conductive substrate, wherein the substrate is flexible.

17. A method for producing the conductive substrate according to claim 1 or 2, The method for producing a conductive substrate, wherein the substrate has optical transparency.

18. A method for producing the conductive substrate according to claim 1 or 2, The method for producing a conductive substrate, wherein the substrate is one or more materials selected from the group consisting of polyester, polyolefin, polyimide, polycarbonate, and paper.

19. A method for producing the conductive substrate according to claim 1 or 2, The method for manufacturing a conductive substrate, wherein the conductor has a conductive pattern.

20. A method for producing an electronic device, comprising producing an electronic device using a conductive substrate obtained by the method for producing a conductive substrate according to claim 1 or 2.

21. 21. The method of manufacturing an electronic device according to claim 20, comprising: The method for manufacturing an electronic device, wherein the electronic device is an RF tag.

22. A method for producing an electromagnetic wave shielding film, comprising producing an electromagnetic wave shielding film using the conductive substrate obtained by the method for producing a conductive substrate according to claim 1 or 2.

23. A method for producing a sheet heating element, comprising producing a sheet heating element using a conductive substrate obtained by the method for producing a conductive substrate according to claim 1 or 2.

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