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 and an electronic device which enhances selective freedom of a base material.SOLUTION: A method for manufacturing a conductive base material includes a formation step S10, a sintering step S20, and a transfer step S30. The formation step S10 applies conductive ink containing conductive particles to a first base material, and forms an ink pattern. The first base material has a water-repellent region and a non-water-repellent region on its surface. The sintering step sinters an ink pattern on the first base material to obtain a conductive pattern. The transfer step transfers the conductive pattern onto a second base material.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] There is a method of forming a conductive pattern such as wiring by sintering a conductive ink containing metal powder.

[0003] Patent Document 1 describes forming a pattern by bringing ink into contact with a substrate having a liquid-repellent surface and a lyophilic pattern on its surface. Patent Document 1 also describes a method of forming an ink pattern on a plate and then transferring the ink pattern from the plate onto a substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-73969 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the method of Patent Document 1, the ink pattern is transferred to the substrate, and then the pattern is formed on the substrate by drying, baking, etc. Therefore, it is necessary to use a substrate that can withstand the baking process.

[0006] An object of the present invention is to increase the degree of freedom in selecting a substrate in a method for producing a conductive substrate or an electronic device. [Means for solving the problem]

[0007] According to one embodiment of the present invention, there are provided the following methods 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.

[0008] 1. A step of applying a conductive ink containing conductive particles to a first substrate having a liquid-repellent region and a non-liquid-repellent region on its surface to form an ink pattern; sintering the ink pattern on the first substrate to obtain a conductive pattern; and transferring the conductive pattern to a second substrate. A method for producing a conductive substrate. 2. In the method for producing a conductive substrate according to 1., In the transferring step, the conductive pattern is transferred to the second substrate via an adhesive layer or a pressure-sensitive adhesive layer. A method for producing a conductive substrate. 3. In the method for producing a conductive substrate according to 1. or 2., The second substrate is at least one selected from the group consisting of polyester, polyolefin, polycarbonate, and paper. A method for producing a conductive substrate. 4. In the method for producing a conductive substrate according to any one of 1. to 3., In the step of forming the ink pattern, the viscosity of the conductive ink is greater than 100 mPa·s. A method for producing a conductive substrate. 5. In the method for producing a conductive substrate according to any one of 1. to 4., The first substrate is cylindrical. A method for producing a conductive substrate. 6. In the method for producing a conductive substrate according to any one of 1. to 5., The contact angle of the conductive ink with respect to the liquid-repellent area is larger than the contact angle of the conductive ink with respect to the non-liquid-repellent area. A method for producing a conductive substrate. 7. In the method for producing a conductive substrate according to any one of 1. to 6., In the step of forming the ink pattern, the conductive ink is selectively applied to the first substrate in a pattern corresponding to the non-liquid repellent area. A method for producing a conductive substrate. 8. In the method for producing a conductive substrate according to 7., In the step of forming the ink pattern, the conductive ink is printed on the first substrate by screen printing, inkjet printing, or dispense printing. A method for manufacturing a conductive substrate. 9. In the method for producing a conductive substrate according to any one of 1. to 8., The method further includes a step of infiltrating the ink pattern with a component capable of removing the oxide film present on the surface of the conductive particles. A method for manufacturing a conductive substrate. 10. In the method for producing a conductive substrate according to any one of 1. to 9., In the step of obtaining the conductive pattern, the ink pattern is sintered by applying at least one of pressure and heat to the ink pattern. A method for manufacturing a conductive substrate. 11. 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 described in any one of 1. to 10. 12. A method for manufacturing an electronic device according to 11, comprising: The method for manufacturing an electronic device, wherein the electronic device is an RF tag. 13. 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 described in any one of 1. to 10. 14. 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 described in any one of 1. to 10. [Effects of the Invention]

[0009] According to the present invention, the degree of freedom in selecting a substrate can be increased in a method for manufacturing a conductive substrate or an electronic device. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing an outline of a method for producing a conductive substrate according to a first embodiment. [Figure 2] 1A to 1C are diagrams illustrating a method for manufacturing a conductive substrate according to a first embodiment. [Figure 3] 1A to 1C are diagrams illustrating a method for manufacturing a conductive substrate according to a first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, like components are designated by like reference numerals, and the description thereof will be omitted as appropriate.

[0012] 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 mass %" means "at least 1 mass % and at most 5 mass %."

[0013] 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 unsubstituted and substituted groups. For example, the term "alkyl group" encompasses not only alkyl groups without a substituent (unsubstituted alkyl groups) but also alkyl groups with a substituent (substituted alkyl groups).

[0014] 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."

[0015] Unless otherwise specified, the term "organic group" as used herein means an atomic group formed by removing one or more hydrogen atoms from an organic compound. For example, a "monovalent organic group" refers to an atomic group formed by removing one hydrogen atom from any organic compound.

[0016] 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.

[0017] (First embodiment) FIG. 1 is a diagram showing an overview of a method for manufacturing a conductive substrate according to a first embodiment. The method for manufacturing a conductive substrate according to this embodiment includes a forming step S10, a sintering step S20, and a transferring step S30. In the forming step S10, a conductive ink containing conductive particles is applied to a first substrate to form an ink pattern. Here, the first substrate has liquid-repellent regions and non-liquid-repellent regions on its surface. In the sintering step, the ink pattern is sintered on the first substrate to obtain a conductive pattern. In the transferring step, the conductive pattern is transferred to a second substrate.

[0018] According to this method for producing a conductive substrate, a conductive substrate is obtained in which a conductive pattern is provided on a second substrate.

[0019] In the method for manufacturing a conductive substrate according to this embodiment, sintering to form a conductive pattern is performed on a first substrate. The conductive pattern is then transferred to a desired second substrate. Therefore, the second substrate does not need to be able to withstand the sintering process, which increases the freedom of selection of the second substrate (i.e., the substrate included in the conductive substrate).

[0020] 2 and 3 are diagrams illustrating a method for manufacturing a conductive substrate 500 according to this embodiment. The method for manufacturing a conductive substrate 500 according to this embodiment will be described in detail below with reference to FIGS. 2 and 3. FIGS. 2 and 3 show cross sections of each element perpendicular to the first surface 102 of the first substrate 10. In the example of FIG. 3, the conductive pattern 22 included in the conductive substrate 500 forms, for example, a circuit pattern in plan view. FIG. 3 shows, as an example, a cross section perpendicular to the extension direction of a portion of the conductive pattern 22 that extends linearly in plan view.

[0021] In the examples of Figures 2 and 3, the preparation process, formation process, infiltration process, sintering process, transfer process, and peeling process are performed in this order, but one or more of the processes other than the formation process, sintering process, and transfer process can be omitted depending on the case.

[0022] <Preparation process> In the example of FIG. 2, in the method for manufacturing the conductive substrate 500, a preparation step of preparing the first substrate 10 is performed before the formation step.

[0023] The first substrate 10 can function as a base for forming the conductive pattern 22. The first substrate 10 is made of a material that can withstand the pressure, temperature, and the like in the sintering process. Furthermore, it is preferable that the first substrate 10 can be easily separated from the conductive pattern 22 in the peeling process. The material of the first substrate 10 is not particularly limited, but the first substrate 10 is, for example, a metal. Examples of metals that constitute the first substrate 10 include alloys in which carbon (C) is added to iron. This alloy may further contain one or more of chromium (Cr), tungsten (W), molybdenum (Mo), and vanadium (V).

[0024] The first substrate 10 may be plate-shaped or cylindrical. When the first substrate 10 is plate-shaped, the thickness of the first substrate 10 is, for example, 0.1 to 3 mm. When the first substrate 10 is plate-shaped, the first surface 102 is one of the main surfaces of the first substrate 10. When the first substrate 10 is cylindrical, the first surface 102 is the circumferential surface of the cylinder. When the first substrate 10 is cylindrical, the first substrate 10 can be rotated as a roll to continuously produce the conductive substrate 500, thereby improving productivity.

[0025] The first substrate 10 has a liquid-repellent region 106 and a non-liquid-repellent region 105 on its surface (first surface 102). In the preparation step, the non-liquid-repellent region 105 and the liquid-repellent region 106 are formed on the first surface 102 of the first substrate 10. The liquid-repellent region 106 and the non-liquid-repellent region 105 have different affinities with respect to conductive ink. That is, the contact angle of the conductive ink with the liquid-repellent region 106 is larger than the contact angle of the conductive ink with the non-liquid-repellent region 105. Preferably, the non-liquid-repellent region 105 is a lyophilic region. Note that, although the non-liquid-repellent region 105 and the liquid-repellent region 106 are shown with different surface shapes in FIGS. 2 and 3, the surface shapes of the non-liquid-repellent region 105 and the liquid-repellent region 106 may be different or the same. The non-liquid-repellent region 105 and the liquid-repellent region 106 are adjacent to each other.

[0026] One example of a method for forming the non-liquid-repellent region 105 and the liquid-repellent region 106 on the first surface 102 of the first substrate 10 is a method in which the entire first surface 102 is made into a liquid-repellent region 106, and then a portion of the liquid-repellent region 106 is made into a non-liquid-repellent region 105. Another example of a method for forming the non-liquid-repellent region 105 and the liquid-repellent region 106 on the first surface 102 of the first substrate 10 is a method in which the entire first surface 102 is made into a non-liquid-repellent region 105, and then a portion of the non-liquid-repellent region 105 is made into a liquid-repellent region 106. Another example of a method for forming a non-liquid-repellent region 105 and a liquid-repellent region 106 on the first surface 102 of the first substrate 10 is a method in which one of the non-liquid-repellent region 105 and the liquid-repellent region 106 is formed on a portion of the first surface 102 of the first substrate 10, and then the other of the non-liquid-repellent region 105 and the liquid-repellent region 106 is formed on the remaining portion of the first surface 102 of the first substrate 10.

[0027] For example, the liquid-repellent region 106 and the non-liquid-repellent region 105 can be formed by surface processing the first surface 102 of the first substrate 10 using laser processing, dry etching, or the like. Specifically, the surface processing is performed on at least one of the region to be the liquid-repellent region 106 and the region to be the non-liquid-repellent region 105, so that the liquid-repellent region 106 and the non-liquid-repellent region 105 have different surface shapes. In this way, two regions with different liquid repellencies can be formed. When forming at least one of the liquid-repellent region 106 and the non-liquid-repellent region 105, the processing can be performed using a mask with openings, for example, to form the non-liquid-repellent region 105 in a desired pattern.

[0028] The method for forming the liquid-repellent areas 106 and the non-liquid-repellent areas 105 is not limited to the above, and they may be formed, for example, by applying a water-repellent material to the first surface 102 of the first substrate 10 in a pattern.

[0029] In the first substrate 10, the non-liquid repellent region 105 is formed in a predetermined pattern. That is, when viewed in a direction perpendicular to the first surface 102, the shape of the non-liquid repellent region 105 is the shape of the desired conductive pattern 22. By appropriately designing the "pattern," it is possible to manufacture a substrate having a pattern structure, such as a conductive film (circuit pattern) that can function as a circuit, a wiring pattern, or a mesh pattern that has electromagnetic wave shielding properties. It is preferable that the "pattern" be appropriately designed depending on the application of the conductive pattern 22 that is ultimately obtained.

[0030] <Formation process> In the forming step, a conductive ink containing conductive particles is applied to a first substrate 10 having a liquid-repellent region 106 and a non-liquid-repellent region 105 on a first surface 102 to form an ink pattern 21. Specifically, the conductive ink is repelled by the liquid-repellent region 106, but is placed on the non-liquid-repellent region 105. In this way, when viewed in a direction perpendicular to the first surface 102, an ink pattern 21 having a shape corresponding to the non-liquid-repellent region 105 is obtained.

[0031] In the forming step, it is preferable to selectively apply the conductive ink to the first substrate 10 in a pattern that corresponds to the non-liquid repellent region 105. By doing so, it is possible to precisely control the shape and thickness of the ink pattern 21. For example, in the forming step, the conductive ink can be printed on the first substrate 10 by various printing methods such as screen printing, inkjet printing, or dispense printing.

[0032] However, if the conductive ink has sufficient fluidity (for example, if the viscosity of the conductive ink is 10 mPa·s or less), the conductive ink may be applied to the entire first surface 102 of the first substrate 10 during the forming process, instead of selectively applying the conductive ink to the first substrate 10 in a pattern corresponding to the non-liquid-repellent regions 105. Even in this case, due to the difference in the surface conditions between the non-liquid-repellent regions 105 and the liquid-repellent regions 106, the conductive ink will spontaneously collect on the non-liquid-repellent regions 105, resulting in the desired ink pattern 21. The viscosity of the conductive ink can be measured at 25°C using, for example, an E-type viscometer manufactured by Toki Sangyo Co., Ltd. The measurement conditions, such as the jig used and the rotation speed during measurement, are selected to enable appropriate measurement depending on the viscosity level.

[0033] The conductive ink may contain conductive particles. From the viewpoints of availability and good conductivity, the conductive particles contained in the conductive ink preferably contain at least one element selected from the group consisting of silver and copper. Specifically, the conductive particles preferably contain at least one element selected from the group consisting of particles primarily composed of silver and particles primarily composed of copper. Here, the expression "based on 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 "based on 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.

[0034] 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.

[0035] 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.

[0036] The particle diameter D at which the cumulative frequency reaches 50% in the volume-based cumulative particle diameter distribution curve obtained when the particle diameter of conductive particles is measured by the laser diffraction scattering method. 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. 50 By making D appropriately large, the number of grain boundaries between conductive particles per unit volume can be reduced. This is thought to lead to a smaller specific resistance of the resulting conductive pattern 22. 50 It is believed that by not making the size too large, the "gaps" between the conductive particles are reduced, which leads to a smaller specific resistance of the resulting conductive pattern 22.

[0037] 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.

[0038] To further reduce the resistivity of the resulting conductive pattern 22, it is preferable that the proportion of conductive particles in the conductive ink is high. Specifically, the proportion of conductive particles in the total non-volatile components of the conductive ink 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, to further reduce the resistivity of the resulting conductive pattern 22, it is preferable that the conductive ink is substantially free of resin components such as resins and binders. Here, "substantially free of resin components" means that the ink does not contain any resin components at all, 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 ink). As long as the desired conductive pattern 22 can be obtained, the conductive ink does not need to contain resins or binders.

[0039] The conductive ink used to form the ink pattern 21 is preferably in a paste state at room temperature to facilitate pattern formation. The viscosity of the conductive ink is preferably, for example, greater than 100 mPa·s. The viscosity of the conductive ink can be measured at 25°C using, for example, an E-type viscometer manufactured by Toki Sangyo Co., Ltd. The conditions for the measurement, such as the jig used and the rotation speed during measurement, are selected to enable appropriate measurement depending on the viscosity level.

[0040] From the viewpoint of further increasing the conductivity of the finally obtained conductive pattern, the amount of resin component in the conductive ink 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 conductive particles. The remaining component in the conductive ink is preferably conductive particles. If there is no problem with pattern formation, the conductive ink does not need to contain a resin component. From the viewpoint of improving conductivity, it is preferable that the conductive ink does not substantially contain a curable component other than the conductive particles.

[0041] On the other hand, from the viewpoint of improving the pattern formability, i.e., the printability and coatability of the conductive ink, the conductive ink 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 ink 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 ink is preferably the conductive particles.

[0042] Specific examples of resin components that can be contained in the conductive ink include polyvinylpyrrolidone, polyester, epoxy resin, (meth)acrylic resin, polyvinyl acetal, cellulose resin (such as ethyl cellulose), and phenol resin.

[0043] The conductive ink may contain a solvent. When the conductive ink contains a solvent, the coating or printing properties of the conductive ink on a substrate are improved. The solvent typically contains an organic solvent. The solvent may contain water as long as the conductive particles can be appropriately dispersed. 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 ink. The amount of solvent used may be adjusted appropriately depending on the coating or printing method of the conductive ink. 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 conductive ink.

[0044] The conductive ink may or may not contain various additive components found in conventional ink compositions and conductive pastes.

[0045] The height of the ink pattern 21 formed in the forming step is preferably 0.5 to 100 μm, more preferably 5 to 60 μm, and even more preferably 10 to 40 μm. If this height is 0.5 μm or more, the conductivity of the final conductive pattern 22 can be improved. On the other hand, if this height is 100 μm or less, the entire conductive substrate 500 including the final conductive pattern 22 can be made thinner. This is preferable from the viewpoint of, for example, reducing the size and weight of electronic devices.

[0046] It is preferable that the conductive particles in the ink pattern 21 are not substantially sintered. Incidentally, in this embodiment, the conductive particles are usually sintered in the sintering step described below. It is preferable that the ink pattern 21 is not substantially cured. Specifically, even if the conductive ink contains a curable resin, a crosslinking agent, or the like, it is preferable that the curable resin or crosslinking agent in the ink pattern 21 be substantially unreacted before the sintering step.

[0047] <Infiltration process> The conductive substrate 500 according to this embodiment may further include a penetration step in which a component (X) capable of removing oxide films present on the surfaces of the conductive particles is penetrated into the ink pattern 21. The penetration step can be performed, for example, between the formation step and the sintering step. By performing the penetration step, sintering of the conductive particles can proceed more easily in the sintering step, which tends to increase the conductivity of the finally obtained conductive pattern 22.

[0048] The component (X) is not particularly limited as long as it can remove the oxide film on the surface of the conductive particles. In this specification, the "removal" of the oxide film includes not only the removal of the oxide itself present on the surface of the conductive particles, but also the chemical change (reduction, etc.) of the oxide, which returns the oxide to a non-oxide.

[0049] According to the findings of the present inventors, it is preferable to include 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 include copper or silver.

[0050] 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, phosphorous acid, phosphoric acid, diphosphate, triphosphate, and metatriphosphate. Among 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-NH structure.

[0051] In addition, from the viewpoint of removing oxide films, 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.

[0052] Considering only the small pKa and the resulting ability to remove oxide films, it is conceivable to use inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid as component (X). However, in consideration of problems that may occur if the component (X) remains in the conductive pattern 22, organic acids are preferred as component (X).

[0053] The pKa value used here can be a value at room temperature (e.g., 25°C). However, from the viewpoint of the removability of the oxide film in the actual process, it may be preferable to use a pKa value at the temperature in the penetration step or sintering step.

[0054] In addition, any compound capable of returning an oxidized film to a non-oxidized state through a reduction reaction can also be used as component (X). For example, a compound having an aldehyde group can sometimes reduce an oxide and can therefore be used as component (X).

[0055] 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). Formic acid is an example of such a compound. Formic acid has the advantage of being easily volatilized and unlikely to remain in the conductive film.

[0056] Other examples of component (X) include pyrogallol, phenidone, hydroquinone, and orthoaminophenol. These are substances known to function as reducing agents in the field of silver halide photography. If a conductive film having a lower resistivity can be obtained when a certain compound A is allowed to penetrate into the ink pattern 21 than when it is not allowed to penetrate, then that compound A can be used as component (X).

[0057] In the penetration step, when the oxide film removal liquid 40 in which the component (X) is dissolved or dispersed is penetrated into the ink pattern 21, the concentration of the component (X) in the liquid may be adjusted as appropriate. The concentration is adjusted from the viewpoint of allowing a sufficient amount of the component (X) to penetrate into the ink pattern 21 and from the viewpoint of reducing the amount of the remaining component (X) to suppress corrosion and deterioration of the conductive pattern 22.

[0058] The concentration of component (X) in oxide film removing solution 40 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, oxide film removing solution 40 containing component (X) at a concentration lower than the concentrations shown here may be used, or oxide film removing solution 40 containing component (X) at a concentration higher than the concentrations shown here (for example, saturated concentration) may be used.

[0059] In the penetration step, a component (X) capable of removing the oxide film on the surface of the conductive particles is penetrated into the ink pattern 21. In the subsequent sintering step, the ink pattern 21 penetrated with the component (X) is at least pressurized to form the conductive pattern 22.

[0060] From the viewpoint of ease of carrying out the process and ease of permeating the component (X) into the ink pattern 21, preferably, in the permeation step, the oxide film removal solution 40 in which the component (X) is dissolved or dispersed is permeated into the ink pattern 21. More preferably, in the permeation step, water in which the component (X) is dissolved or dispersed is permeated into the ink pattern 21. Using "water" in which the component (X) is dissolved or dispersed is preferable from the viewpoint of reducing the environmental load and ensuring the safety of the process (non-flammable). Of course, an organic solvent in which the component (X) is dissolved or dispersed can also be used.

[0061] In the penetration step, for example, first, an oxide film removal solution 40 containing component (X) is supplied to at least the surface of the ink pattern 21 by any method such as dropping, spraying, or immersion, and the liquid containing component (X) is allowed to penetrate into the ink pattern 21 under normal pressure or under pressure. Then, a sintering step is performed.

[0062] As another example, the ink pattern 21 is exposed to a "gas" containing component (X) to allow component (X) to penetrate into the ink pattern 21, and then the sintering step is performed. In this case, if component (X) is a gas at room temperature and normal pressure, the penetration step may be performed at room temperature and normal pressure. Alternatively, if component (X) is a liquid or solid at room temperature and normal pressure, component (X) may be heated to vaporize it, and the vaporized component (X) may be brought into contact with the ink pattern 21.

[0063] When the sintering step is carried out after the permeation step, the component (X) that has not permeated into the ink pattern 21 in the permeation step may or may not be removed before the sintering step is carried out.

[0064] Furthermore, after the sintering step, a removal step may be performed to remove component (X) remaining on the surface or inside the obtained conductive pattern 22. Specifically, examples of such a step include a step of immersing the obtained conductive pattern 22 on the first substrate 10 or the second substrate 50 in a liquid (water or an organic solvent) capable of dissolving or dispersing component (X), or a step of "washing away" the remaining component (X) by pouring a liquid (water or an organic solvent) onto the surface of the conductive pattern 22. Another possible step is to "vaporize and remove" the remaining component (X) by heating the obtained conductive pattern 22.

[0065] Incidentally, when a sintering step is carried out after the infiltration step, there is a possibility that removal of a part of the oxide film by the component (X) may proceed even during the sintering step.

[0066] When the sintering step is performed after the infiltration step, the time between the infiltration step and the sintering step is preferably short so as to prevent the formation of an oxide film again on the surface of the conductive particles from which the oxide film was removed in the infiltration step. Specifically, when the sintering step is performed after the infiltration step, the time from the end of the infiltration step to the start of the sintering step is preferably 1 hour or less, more preferably 30 minutes or less, even more preferably 10 minutes or less, and particularly preferably 1 minute or less.

[0067] Alternatively, in order to prevent an oxide film from being formed again on the surface of the conductive particles from which the oxide film has been removed in the penetration process, the first substrate 10 and the ink pattern 21 after the penetration process and before the sintering process may be placed in an inert gas atmosphere such as a noble gas or nitrogen gas, a reducing atmosphere, or a vacuum or reduced pressure.

[0068] <Sintering process> In the sintering step, the ink pattern 21 is sintered on the first substrate 10 to obtain the conductive pattern 22. Specifically, in the sintering step according to this embodiment, the ink pattern 21 is sintered by applying at least one of pressure and heat to the ink pattern 21. That is, in the sintering step, the ink pattern 21 may be subjected to only pressure, only heating, or both heating and pressure. When both heating and pressure are applied, the heating and pressure may be applied simultaneously, or one heating and pressure may be applied in sequence. When heating and pressure are applied in sequence, the pressure may be applied after heating, or the heating may be applied after pressure.

[0069] In the manufacturing method of the conductive substrate 500 according to this embodiment, at least one of pressurization and heating is performed on the ink pattern 21 on the first substrate 10, so there is no need to consider damage to the substrate or heat damage, as is the case when at least one of pressurization and heating is performed on a substrate included in the finished conductive substrate. Therefore, at least one of pressurization and heating can be performed under conditions that allow a conductive pattern 22 with low resistivity to be obtained.

[0070] When the ink pattern 21 is heated in the sintering step, the heating temperature may be set appropriately depending on the type of conductive particles used, etc. The heating temperature may be 50 to 400°C. The heating time may also be set appropriately depending on the type of conductive particles used, etc. The heating time may be, for example, 0.01 to 1 second, preferably 0.04 to 0.6 seconds. If a conductive film with sufficiently low resistivity can be obtained, it is not necessary to heat the ink pattern 21 in the sintering step. In particular, when particles containing silver as the main component are used as the conductive particles, a conductive pattern 22 with sufficiently low resistivity can easily be obtained by applying pressure alone.

[0071] In the sintering step, the ink pattern 21 disposed on the first substrate 10 may be heated using a heater to sinter the ink pattern 21. The heater may be provided on the first substrate 10, on a pressing member described below, or on both the first substrate 10 and the pressing member. Alternatively, the ink pattern 21 may be heated by heaters provided external to the first substrate 10 and the pressing member. In this case, methods such as optical heating and far-infrared heating can be used. Note that if pressure is not applied in the sintering step, a pressing member need not be used in manufacturing the conductive substrate 500.

[0072] When the ink pattern 21 is pressurized in the sintering process, the pressure applied to the ink pattern 21 is, for example, 1 MPa or more, preferably 10 MPa or more, more preferably 10 to 5000 MPa, even more preferably 20 to 1000 MPa, particularly preferably 30 to 300 MPa, and especially preferably 50 to 250 MPa. By applying a relatively large pressure to the ink pattern 21, the resistivity of the finally obtained conductive pattern 22 can be further reduced. Furthermore, by not applying too large a pressure, damage to the first substrate 10 and the ink pattern 21 can be suppressed. Incidentally, if the strength of the first substrate 10 is sufficient, the pressure can be increased to further reduce the resistivity of the finally obtained conductive pattern 22.

[0073] When the ink pattern 21 is heated and pressurized in the sintering step, the ink pattern 21 is preferably pressed at a pressure of 1 to 5000 MPa and heated at a temperature of 50 to 400°C. More preferably, the ink pattern 21 is pressed at a pressure of 30 to 1000 MPa and heated at a temperature of 70 to 200°C. Even more preferably, the ink pattern 21 is pressed at a pressure of 50 to 300 MPa and heated at a temperature of 80 to 150°C.

[0074] In the sintering process, pressure is applied using a pressing member. An example of a pressing member is a roll. That is, in the sintering process, for example, roll pressing is performed. Specifically, as shown in FIG. 3, a laminate including the first substrate 10 and the ink pattern 21 is sandwiched between the side surface (circumferential surface) of roll 30a and the side surface (circumferential surface) of roll 30b, and pressure is applied by rotating roll 30a and roll 30b. In the case of roll pressing, the ink pattern 21 is pressed between the curved surfaces. Furthermore, the laminate including the first substrate 10 and the ink pattern 21 is transported while being pressed between roll 30a and roll 30b.

[0075] As another example, the pressing member may be a flat plate. In this case, the ink pattern 21 is pressed between two flat surfaces. When the ink pattern 21 is pressed between two flat surfaces, pattern thickening tends to be suppressed compared to when a roll press is used.

[0076] As yet another example, a laminate including first substrate 10 and ink pattern 21 may be placed on a flat plate, a roll may be applied from above, and the ink pattern 21 may be pressed while rolling. Alternatively, a method may be considered in which a flat plate is applied to the laminate including first substrate 10 and ink pattern 21, a roll may be applied from below the laminate, and the ink pattern 21 may be pressed while rolling. Furthermore, when first substrate 10 is cylindrical, first substrate 10 may also serve as roll 30b.

[0077] The pressing member is made of a material that can withstand the pressure and temperature in the sintering process. The material of the pressing member is not particularly limited, but is, for example, a metal.

[0078] In the sintering process, the ink pattern 21 is pressed in a direction perpendicular to the first surface 102 of the first substrate 10 .

[0079] When pressurizing the ink pattern 21, it is preferable to cover the exposed surface of the ink pattern 21 with a covering member 60, as shown in Fig. 3, and then pressurize the ink pattern 21. In other words, it is preferable to pressurize a laminate including the first substrate 10, the ink pattern 21, and the covering member 60. The covering member 60 is preferably a film-like material.

[0080] Incidentally, when the penetration step is performed before the sintering step, the oxide film removal solution 40 is present on top of the ink pattern 21. In this case, it is thought that the component (X) penetrates into the ink pattern 21 by pressure and removes the oxide film of the conductive particles, while sintering the conductive particles proceeds in parallel.

[0081] There are several advantages to using the covering member 60 when applying pressure. Examples of the advantages include the following: Damage to the roll 30a can be suppressed. In addition, it may be possible to suppress the ink pattern 21 from partially or entirely peeling off and adhering to the roll 30a. Since the roll 30a is prevented from coming into direct contact with the ink pattern 21, unintended deformation or collapse of the ink pattern 21 can be easily prevented. The covering member 60 acts as a "buffer," making it easier to apply pressure uniformly to the ink pattern 21. This leads to, for example, an improvement in the yield of the final conductive substrate 500. Furthermore, when the infiltration step is performed before the sintering step, applying pressure uniformly to the ink pattern 21 is also preferable because it leads to the component (X) being uniformly infiltrated into the ink pattern 21.

[0082] From one perspective, the covering member 60 can be preferably a polyester film such as a PET film. From another perspective, from the viewpoint of preventing peeling or damage to the ink pattern 21, an easily peelable film or release paper can be preferably used as the covering member 60. From yet another perspective, the covering member 60 may be made of a non-resin material such as aluminum foil.

[0083] On the other hand, in order to simplify the manufacturing process and reduce waste by reducing the amount of process materials, pressurization may be performed without using the covering member 60.

[0084] Through the sintering process, the conductive pattern 22 is obtained from the ink pattern 21. That is, through the sintering process, the ink pattern 21 is integrated into a film-like shape to become the conductive pattern 22. In the conductive pattern 22, the multiple conductive particles contained in the ink pattern 21 are sintered. In this way, the conductive pattern 22 corresponding to the shape of the non-liquid repellent region 105 is formed on the first substrate 10.

[0085] <Transfer process> After the sintering step, a transfer step is performed in which the conductive pattern 22 is transferred from the first substrate 10 to a second substrate 50 that is different from the first substrate 10.

[0086] The second substrate 50 is, for example, in the form of a film, sheet, or plate. The second substrate 50 is preferably flexible. By employing a flexible second substrate 50, a flexible printed circuit (FPC) or a flexible device can be manufactured. However, the second substrate 50 may also be a rigid substrate that does not have flexibility.

[0087] Considering cost and end use, the second substrate 50 is preferably 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, polyimide, polycarbonate, glass, epoxy resin, phenolic resin, and paper. The paper may be coated paper (paper whose surface is coated with a coating agent) or ordinary uncoated paper. The second substrate 50 is not limited to PET, and any ordinary resin film can be used. The second substrate 50 may be transparent or opaque. Examples of opaque resin films include foamed resin films or foamed resin sheets, such as foamed PET films.

[0088] The second substrate 50 may be at least one selected from the group consisting of polyester, polyolefin, polycarbonate, and paper. In this embodiment, since the conductive pattern 22 is formed by processing the conductive material 20 on the first substrate 10 in the sintering step, the second substrate 50 does not require high levels of heat resistance or pressure resistance. Therefore, materials with low heat resistance and low pressure resistance, such as polyester, polyolefin, polycarbonate, and paper, can also be suitably used as the second substrate 50.

[0089] In the transfer step, the conductive pattern 22 is transferred to the second substrate 50 via an adhesive layer or pressure-sensitive adhesive layer 52. The target surface of the second substrate 50 onto which the conductive pattern 22 is to be transferred preferably has a size large enough to cover the entire ink pattern 21.

[0090] The adhesive layer 52 can be made of a resin material. Specifically, it can be made of an acrylic resin. The adhesive layer 52 has adhesiveness. The adhesive layer 52 can also be made of a commercially available product. The thickness of the adhesive layer 52 is, for example, 1 to 100 μm.

[0091] Although FIG. 3 shows a case where an adhesive layer 52 is used, this example is not limiting. The conductive pattern 22 may be transferred to the second substrate 50 via an adhesive layer. In this case, the adhesive layer is preferably thermosetting or photocurable. The adhesive layer is more preferably formed from a thermosetting resin material or a photocurable resin material. When the second substrate 50 is light-transmitting, the adhesive layer can be made photocurable so that it can be cured by irradiating light from the second substrate 50 side. When the second substrate 50 is not light-transmitting, the adhesive layer can be made thermosetting so that it can be cured by heating.

[0092] The adhesive layer may be made of various 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.

[0093] The adhesive layer may be made of a commercially available product, for example, any of various thermosetting or photocurable resin materials known or commercially available as hard coating agents.

[0094] If the adhesive layer is thermosetting, it is preferable to form the adhesive layer so that the thermosetting proceeds at a heating temperature that does not damage the second substrate 50. For example, if the second substrate 50 is made of a resin, it is preferable to design the adhesive layer so that the curing reaction proceeds sufficiently when heated at a temperature lower than the glass transition temperature of the resin.

[0095] In the transfer step, the adhesive layer preferably comes into contact with the conductive pattern 22 in an uncured or semi-cured state, more preferably in an uncured state. The adhesive layer is then cured to fix the conductive pattern 22 to the second substrate 50. The adhesive layer may be cured before or after the peeling step described below.

[0096] The thickness of the adhesive layer is not particularly limited, but is preferably 1 to 30 μm in order to obtain sufficient adhesiveness. The adhesive layer may be a single layer or may have two or more layers. For example, if the second substrate 50 is paper, a two-layer adhesive layer may be used in consideration of penetration into the fibrous paper. In this case, the first adhesive layer closest to the paper plays the role of "sealing."

[0097] 3, the adhesive or pressure-sensitive adhesive layer 52 may be formed in advance on the second substrate 50. In this case, in the transfer step, the conductive pattern 22 is transferred by pressing a laminate of the second substrate 50 and the pressure-sensitive adhesive layer 52 against the conductive pattern 22 on the first substrate 10. At this time, the second substrate 50 may be pressed against the conductive pattern 22 using a roll, a planar member, or the like.

[0098] The adhesive or pressure-sensitive adhesive layer 52 may be provided over the entire target surface of the second substrate 50 onto which the conductive pattern 22 is to be transferred, or may be provided only in a partial region of the target surface of the second substrate 50. The adhesive or pressure-sensitive adhesive layer 52 is provided in at least the target region of the target surface of the second substrate 50 onto which the conductive pattern 22 is to be transferred. The adhesive or pressure-sensitive adhesive layer 52 may be provided only in the target region of the target surface of the second substrate 50, or may be provided in areas other than the target region.

[0099] As another example, the adhesive or pressure-sensitive adhesive layer 52 may be provided on the first substrate 10 side prior to transfer. That is, the adhesive or pressure-sensitive adhesive layer 52 may be laminated on the conductive pattern 22. In this case, in the transfer step, the conductive pattern 22 is transferred by pressing the second substrate 50 against the laminate of the adhesive or pressure-sensitive adhesive layer 52 and the conductive pattern 22. At this time, the second substrate 50 may be moved toward the laminate of the adhesive or pressure-sensitive adhesive layer 52 and the conductive pattern 22, or the laminate of the adhesive or pressure-sensitive adhesive layer 52 and the conductive pattern 22 may be moved toward the second substrate 50. At this time, the second substrate 50 may be pressed against the conductive pattern 22 using a roll, a planar member, or the like.

[0100] When the adhesive or pressure-sensitive adhesive layer 52 is provided on the first substrate 10 side prior to transfer, the adhesive or pressure-sensitive adhesive layer 52 may be provided on both the conductive pattern 22 and the area of ​​the first surface 102 that is not covered with 22, or may be provided only on the conductive pattern 22. The adhesive or pressure-sensitive adhesive layer 52 is provided at least on the conductive pattern 22.

[0101] <Peeling process> After the transfer step, a peeling step is performed. In the peeling step, the second substrate 50 is separated from the first substrate 10, thereby peeling the conductive pattern 22 from the first substrate 10. The conductive pattern 22 is peeled from the first substrate 10 while still attached to the second substrate 50 via the adhesive or pressure-sensitive adhesive layer 52. In this way, a conductive substrate 500 including the conductive pattern 22 is obtained. Note that the conductive substrate 500 does not need to be conductive as a whole, and includes the second substrate 50 and the conductive pattern 22. Furthermore, the conductive substrate 500 may include an adhesive or pressure-sensitive adhesive layer 52 between the second substrate 50 and the conductive pattern 22.

[0102] The conductive pattern 22 provided on the second base material 50, i.e., the conductive pattern 22 provided on the conductive base material 500, is a conductive film having a desired pattern shape. The thickness of the conductive pattern 22 provided on the second base material 50 is preferably 5 to 100 μm, and more preferably 10 to 50 μm.

[0103] According to the method for manufacturing the conductive substrate 500 of this embodiment, the second substrate 50 has a high degree of freedom in selection, and the conductive pattern 22 having good conductivity can be obtained.

[0104] The conductive pattern 22 on the second substrate 50 obtained by the manufacturing method including the above-mentioned infiltration step may, but does not necessarily, contain the component (X) on the surface or inside the conductive pattern 22 due to the manufacturing method. That is, the conductive substrate 500 includes the second substrate 50 and the conductive pattern 22 provided on at least a portion of the surface of the second substrate 50, and the component (X) may be present on the surface or inside the conductive pattern 22.

[0105] The component (X) present on or inside the conductive pattern 22 can be confirmed by various measurement and observation methods. For example, by observing the conductive film with an electron microscope, it may be possible to observe a salt formed by the reaction between the conductive particles and the component (X). In addition, the component (X) present on or inside the conductive pattern 22 may be detected by other methods such as transmission electron microscopy, X-ray diffraction, nuclear magnetic resonance, infrared spectroscopy, ultraviolet-visible absorption spectroscopy, and Raman spectroscopy.

[0106] <Other processes> When the conductive ink contains a solvent, the method for manufacturing the conductive substrate 500 may further include a step of volatilizing the solvent. Examples of methods for volatilizing the solvent include hot air drying, heating, and light irradiation.

[0107] The step of volatilizing the solvent is preferably carried out after the forming step and before the sintering step.

[0108] For example, when the solvent is evaporated on the first substrate 10, heating can be performed using a heater provided on the first substrate 10 or a heater provided outside the first substrate 10. The conditions for the heat treatment are not particularly limited as long as the solvent is sufficiently dried, but are adjusted from the viewpoint of sufficient drying of the solvent and prevention of deterioration of the conductive particles 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.

[0109] When the ink pattern 21 is heated in the sintering step, a cooling step may be further carried out after the sintering step. The cooling step is preferably carried out before the peeling step. In the cooling step, the conductive pattern 22 is cooled. The conductive pattern 22 can be cooled by placing the conductive pattern 22 in an unheated state. The cooling time is, for example, 5 to 120 seconds.

[0110] The above-described steps may be performed continuously or discontinuously. From the viewpoint of mass production, it is preferable to perform the steps continuously. The first substrate 10 can be reused. That is, a plurality of conductive substrates 500 can be manufactured using the same first substrate 10. Furthermore, it is also possible to form conductive patterns 22 on a plurality of second substrates 50 made of different materials using the same first substrate 10. However, the above-described formation process of the non-liquid repellent region 105 and the liquid repellent region 106 may be performed each time a conductive substrate 500 is manufactured, or at predetermined intervals.

[0111] <Electronic device manufacturing method> An electronic device can be manufactured using the conductive substrate 500 obtained as described above. For example, when forming the conductive pattern 22 only on a portion of one surface of the second substrate 50, by appropriately designing the "pattern," it is possible to manufacture a substrate (conductive substrate 500) equipped with a conductive film (circuit pattern) that can function as a circuit. Then, by combining this conductive substrate 500 with other electronic elements, an electronic device can be manufactured.

[0112] Here, some examples of "electronic devices" are described. For clarity, it should be noted that the electronic devices including the conductive substrate 500 obtained by the manufacturing method of the conductive substrate 500 of the present embodiment are not limited to these examples. Sensors: For example, the conductive substrate 500 obtained by the method for producing the conductive substrate 500 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 500 obtained by the method for producing the conductive base material 500 of this embodiment can be applied to current collecting wiring of solar cells. Membrane switch: A membrane switch is a thin sheet-like switch in which circuits and contacts are printed on a film and then laminated. The manufacturing method of the conductive substrate 500 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 500 of this embodiment can be applied to form lead wiring in a touch sensor / touch panel. It is also conceivable that the manufacturing method of the conductive substrate 500 of this embodiment can be applied to form transparent electrodes in a touch sensor / touch panel. Flexible substrate: Conventionally, a circuit is formed by first coating a metal film on the entire surface of a flexible film and then removing unnecessary parts 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 500 of this embodiment.

[0113] By using the manufacturing method of the conductive substrate 500 of this embodiment, the surface roughness of the conductive pattern 22 can be reduced, and therefore, when an element such as a chip is mounted on the conductive pattern 22, stability is improved.

[0114] A particularly preferred electronic device is an RF (Radio Frequency) tag. That is, the method for manufacturing the conductive substrate 500 of this embodiment is preferably used to manufacture a conductive circuit such as an antenna portion in an RF tag. For the specific structure of the RF tag, reference can be made to, for example, JP 2003-332714 A and JP 2020-46834 A.

[0115] <Method of manufacturing electromagnetic wave shielding film> As an application other than electronic devices, it is conceivable to manufacture an electromagnetic wave shielding film using the conductive substrate 500 obtained by the manufacturing method of the conductive substrate 500 of the present embodiment. Specifically, an electromagnetic wave shielding film can be manufactured by forming the conductive pattern 22 into a pattern (such as a mesh pattern) specific to the electromagnetic wave shielding film.

[0116] <Method of manufacturing a sheet heating element> As yet another application, it is conceivable to manufacture a sheet heating element using the conductive substrate 500 obtained by the manufacturing method of the conductive substrate 500 of this embodiment. A sheet heating element is an element that generates heat by providing electrical wiring on a substrate and passing an electric current through the wiring. 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 car.

[0117] As described above, according to this embodiment, the ink pattern 21 on the first substrate 10 is sintered to obtain the conductive pattern 22, and the conductive pattern 22 is transferred to the second substrate 50. This improves the degree of freedom in selecting the second substrate 50 when manufacturing the conductive substrate 500.

[0118] (Second embodiment) The method for producing the conductive substrate 500 according to the second embodiment is the same as the method for producing the conductive substrate 500 according to the first embodiment, except for the points described below.

[0119] The method for manufacturing the conductive substrate 500 according to the second embodiment includes, for example, a light irradiation step. In the light irradiation step, light is irradiated onto the ink pattern 21. The light irradiation step can be performed as part of the sintering step.

[0120] In the manufacturing method of the conductive substrate 500 according to this embodiment, the sintering process may include multiple processes. For example, the sintering process may include a first sintering process and a second sintering process. The first sintering process is a light irradiation process in which the ink pattern 21 is irradiated with light. Then, in the second sintering process, the ink pattern 21 is subjected to at least one of heating and pressurization. The first sintering process is preferably performed before the second sintering process. The second sintering process is as described above in the first embodiment. In the manufacturing method of the conductive substrate 500 according to this embodiment, when the sintering process includes the first sintering process and the second sintering process, the sintering of the conductive particles in the ink pattern 21 progresses through these processes.

[0121] In the method for producing the conductive substrate 500 according to this embodiment, the ink pattern 21 may be irradiated with light only in the sintering step without being heated or pressed.

[0122] When the manufacturing method of the conductive substrate 500 according to this embodiment includes a permeation step, the permeation step is preferably performed before the second sintering step. Alternatively, the permeation step may be performed between the first and second sintering steps. For example, the permeation step may be performed after the first sintering step and before the second sintering step.

[0123] When the method for producing the conductive substrate 500 according to this embodiment includes a step of volatilizing the solvent, the step of volatilizing the solvent is preferably performed before the light irradiation step, or between the formation step and the light irradiation step.

[0124] The conductive ink according to this embodiment preferably contains a resin. The amount of the resin component in the conductive ink according to this embodiment is as described in the first embodiment.

[0125] In the light irradiation step, light is irradiated onto the ink pattern 21, which can decompose at least a portion of the resin in the conductive ink. Furthermore, in the light irradiation step, sintering of the conductive particles in the conductive ink progresses. Furthermore, in the second sintering step, pressure is applied, which allows a conductive substance to fill the gaps created by the disappearance of the resin, thereby obtaining a low-resistance conductive pattern 22. Note that, in the first sintering step, heating may be performed instead of the light irradiation step. At least a portion of the resin can also be decomposed by heating. The heating temperature in the first sintering step can be, for example, 250 to 350°C. Furthermore, by setting the heating temperature to 350°C or higher, thermal decomposition is greatly promoted.

[0126] The light source used in the light irradiation step is not particularly limited, but a white light source that can provide continuous brightness over a wide wavelength range is preferred. Specific examples include one or more types selected from the group consisting of a xenon flash lamp, a xenon short arc lamp, a ceramic xenon short arc lamp (UXR), a krypton arc lamp, a high-pressure mercury lamp, a xenon mercury lamp, a metal halide lamp, an external electrode rare gas fluorescent lamp, a halogen lamp, and a deuterium lamp. Among these, it is more preferred to use a xenon flash lamp for light-curing, in order to reduce the load on the first substrate 10.

[0127] Xenon flash lamps have a continuous spectrum in the wavelength range from 200 nm to 1000 mm. The amount of radiation energy is 10 J / cm 2 More than 25J / cm 2 Less than 15 J / cm is preferable. 2 More than 25J / cm 2 Less than 20 J / cm is more preferable. 2 More than 25J / cm 2 More preferably, the irradiation time is 0.1 × 10 -3 10x10 seconds or more -3 seconds or less is preferable, and 1×10 -3 8x10 seconds or more -3 Less than 2×10 is preferable. -3 5x10 seconds or more -3Seconds or less is even more preferable.

[0128] In the light irradiation step, it is preferable to irradiate the upper surface of the ink pattern 21, that is, the surface of the ink pattern 21 opposite to the first substrate 10, with light.

[0129] In this embodiment as well, the ink pattern 21 is irradiated with light on the first substrate 10, so there is no need to consider damage to the substrate or heat damage, as in the case of performing photosintering on a substrate included in a finished conductive substrate. Therefore, sintering can be performed under conditions that allow a conductive pattern 22 with low resistivity to be obtained.

[0130] The conductive substrate 500 obtained by the method for producing the conductive substrate 500 according to this embodiment can also be used to produce electronic devices, electromagnetic wave shielding films, and sheet heating elements, similar to the first embodiment.

[0131] Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the above-described embodiments may be combined within the scope of the present invention. [Explanation of symbols]

[0132] 10 First base material 21 Ink Pattern 22 Conductive pattern 30a roll 30b roll 40 Oxide film remover 50 Second base material 52 Adhesive layer 60 Covering material 102 Page 1 105 Non-liquid repellent area 106 Liquid repellent area 500 Conductive substrate

Claims

1. forming an ink pattern by applying a conductive ink containing conductive particles to a first substrate having a liquid-repellent region and a non-liquid-repellent region on a surface thereof; sintering the ink pattern on the first substrate to obtain a conductive pattern; and transferring the conductive pattern to a second substrate. A method for manufacturing a conductive substrate.

2. The method for producing a conductive substrate according to claim 1, In the transferring step, the conductive pattern is transferred to the second substrate via an adhesive layer or a pressure-sensitive adhesive layer. A method for manufacturing a conductive substrate.

3. The method for producing a conductive substrate according to claim 1 or 2, The second substrate is at least one selected from the group consisting of polyester, polyolefin, polycarbonate, and paper. A method for manufacturing a conductive substrate.

4. The method for producing a conductive substrate according to claim 1 or 2, The viscosity of the conductive ink is greater than 100 mPa·s. A method for manufacturing a conductive substrate.

5. The method for producing a conductive substrate according to claim 1 or 2, The first substrate is cylindrical. A method for manufacturing a conductive substrate.

6. The method for producing a conductive substrate according to claim 1 or 2, The contact angle of the conductive ink with respect to the liquid-repellent area is larger than the contact angle of the conductive ink with respect to the non-liquid-repellent area. A method for manufacturing a conductive substrate.

7. The method for producing a conductive substrate according to claim 1 or 2, In the step of forming the ink pattern, the conductive ink is selectively applied to the first substrate in a pattern corresponding to the non-liquid repellent area. A method for manufacturing a conductive substrate.

8. The method for producing a conductive substrate according to claim 7, In the step of forming the ink pattern, the conductive ink is printed on the first substrate by screen printing, inkjet printing, or dispense printing. A method for manufacturing a conductive substrate.

9. The method for producing a conductive substrate according to claim 1 or 2, The method further includes a step of infiltrating the ink pattern with a component capable of removing the oxide film present on the surface of the conductive particles. A method for manufacturing a conductive substrate.

10. The method for producing a conductive substrate according to claim 1 or 2, In the step of obtaining the conductive pattern, the ink pattern is sintered by applying at least one of pressure and heat to the ink pattern. A method for manufacturing a conductive substrate.

11. 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.

12. 12. The method for manufacturing an electronic device according to claim 11, The method for manufacturing an electronic device, wherein the electronic device is an RF tag.

13. 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 claim 1 or 2.

14. 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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