Method for manufacturing substrate provided with conductive pattern, method for manufacturing electronic device, method for manufacturing electromagnetic wave shielding film, method for manufacturing planar heat generator, and article for manufacturing substrate provided with conductive pattern

Abstract

A method for manufacturing a substrate having a conductive pattern includes: a transfer step in which a provisional pattern disposed on the surface of an easy-to-peel substrate by means of a conductive composition containing conductive particles is brought into contact with an adhesive layer disposed on the surface of a substrate different from the easy-to-peel substrate, thereby obtaining a transfer pattern in which the provisional pattern is transferred to the surface of the adhesive layer; and a pressing step in which at least pressure is applied to the transfer pattern to obtain the conductive pattern.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a substrate having conductive patterns, a method for manufacturing electronic devices, a method for manufacturing an electromagnetic wave shielding film, a method for manufacturing a planar heating element, and an article for manufacturing a substrate having conductive patterns. Background Technology

[0002] A known technique involves creating a pattern on a substrate using a conductive composition containing conductive particles, and then obtaining a conductive pattern by heating the pattern. This technique is considered applicable to the rapidly developing printed electronics technology. Printed electronics technology refers to the technique of forming electronic circuits, sensors, components, etc., on substrates such as films using printing techniques.

[0003] Patent Document 1 discloses a method for forming a conductive film pattern, which includes: a step of forming a first conductive film pattern on a separation substrate having a porous receptive layer; and a step of separating the first conductive film pattern from the separation substrate by adhering it to the substrate.

[0004] Patent Document 2 discloses a transfer substrate characterized by its function of temporarily holding a pattern and transferring the held pattern onto a substrate. The transfer substrate has at least a porous layer on a support and a dissociation layer on the porous layer, the porous layer containing a compound selected from at least one of glycerol and polyglycerol. Patent Document 2 also describes using this transfer substrate to form a pattern from an ink or paste containing conductive particles, thereby obtaining a conductive pattern.

[0005] Patent Document 3 discloses a method for manufacturing a smooth wiring circuit board, comprising: (1) forming a B-stage adhesive layer on an amorphous insulating substrate using a thermosetting resin; and (2) transferring conductive pattern portions formed on a film-like temporary substrate by screen printing or the like onto the adhesive layer. According to Patent Document 3, a smooth wiring circuit board is provided in which, by the above manufacturing method, conductive pattern portions that become switch contacts are smoothly and well embedded in a printed wiring board used for a switch substrate such as a slide switch, in a manner that obtains stable switching characteristics.

[0006] Patent document 4 describes a transferable material characterized by having: a substrate having a pattern formed from a conductive material transferred from a letterpress; and an adhesive layer coated on the surface of the substrate and bonding the conductive material thereon.

[0007] Patent Document 5 describes a method for manufacturing a wiring substrate by transferring a conductor pattern onto a substrate using gravure printing. Specifically, the method includes: (1) a gravure printing process for forming grooves on a flexible film surface; (2) a filling process after the gravure printing process for filling the grooves with a conductive paste; (3) a drying process after the filling process for evaporating and drying the solvent contained in the conductive paste filled into the grooves; (4) a transfer process after the drying process for bonding the dried gravure printing plate with the conductive paste to the substrate pre-coated with a thermoplastic adhesive; (5) a film peeling process after the transfer process for peeling the film off the substrate and transferring the conductive paste onto the substrate to form a conductor pattern; and (6) a firing process after the film peeling process for firing the conductive paste. Furthermore, a heating process is inserted between the film peeling process and the firing process to suppress the flow of the adhesive during the firing process.

[0008] Patent Document 1: Japanese Patent Application Publication No. 2004-281658

[0009] Patent Document 2: Japanese Patent Application Publication No. 2020-161619

[0010] Patent Document 3: Japanese Patent Application Publication No. 7-45159

[0011] Patent Document 4: Japanese Patent Application Publication No. 2004-095882

[0012] Patent Document 5: Japanese Patent Application Publication No. 2004-319731

[0013] When conductive patterns are set on a substrate using a conductive composition containing conductive particles, adhesion problems such as pattern peeling may sometimes occur.

[0014] The inventors have conducted various studies with one of their objectives in improving the adhesion of conductive patterns when using conductive compositions containing conductive particles on a substrate. Summary of the Invention

[0015] The inventors have completed the invention described below, which solves the above-mentioned problems.

[0016] 1.

[0017] A method for manufacturing a substrate having a conductive pattern, characterized in that it includes:

[0018] In the transfer process, a provisional pattern, provided on the surface of an easy-to-peel substrate using a conductive composition containing conductive particles, comes into contact with an adhesive layer provided on the surface of a substrate different from the easy-to-peel substrate, thereby obtaining a transfer pattern in which the provisional pattern is transferred to the surface of the adhesive layer; and

[0019] In the pressing process, pressure is applied to the above-mentioned transfer pattern to obtain a conductive pattern.

[0020] 2.

[0021] According to the manufacturing method of the substrate having a conductive pattern described in 1, wherein,

[0022] The aforementioned adhesive layer has at least one of thermosetting or photocuring properties.

[0023] Between the above-mentioned transfer process and the above-mentioned pressing process, there is an adhesive layer curing process that cures the above-mentioned adhesive layer.

[0024] 3.

[0025] According to the manufacturing method of the substrate having a conductive pattern as described in 1. or 2, wherein,

[0026] The conductive particles in the above provisional pattern are not actually sintered.

[0027] 4.

[0028] According to any one of the methods for manufacturing a substrate having a conductive pattern as described in 1. to 3, wherein,

[0029] The aforementioned provisional pattern is not actually solidified.

[0030] 5.

[0031] According to any one of the methods for manufacturing a substrate having a conductive pattern as described in 1. to 4, wherein,

[0032] After the above-mentioned transfer process and before or simultaneously with the above-mentioned pressing process, there is an oxide film removal process that involves bringing the component X of the oxide film on the surface capable of removing the above-mentioned conductive particles into contact with the above-mentioned transfer pattern.

[0033] 6.

[0034] According to any one of the methods for manufacturing a substrate having a conductive pattern as described in 1. to 5, wherein,

[0035] In the pressing process described above, the transfer pattern is heated while pressure is applied to the transfer pattern.

[0036] 7.

[0037] According to the manufacturing method of the substrate having a conductive pattern described in 6., wherein,

[0038] In the pressing process described above, the transfer pattern is pressed with a pressure of 1 to 5000 MPa and heated with a temperature of 50 to 400°C.

[0039] 8.

[0040] According to any one of the methods for manufacturing a substrate having a conductive pattern as described in 1. to 7, wherein,

[0041] The above-mentioned conductive components are in the form of a paste at room temperature.

[0042] 9.

[0043] According to any one of the methods for manufacturing a substrate having a conductive pattern as described in 1. to 8, wherein,

[0044] The amount of resin component in the above conductive composition is 15 parts by mass or less relative to 100 parts by mass of the above conductive particles.

[0045] 10.

[0046] According to any one of the methods for manufacturing a substrate having a conductive pattern as described in 1. to 9, wherein,

[0047] The aforementioned conductive components, as components other than the aforementioned conductive particles, do not actually contain any curing components.

[0048] 11.

[0049] According to any one of the methods for manufacturing a substrate having a conductive pattern as described in 1. to 10, wherein,

[0050] In the volume-based cumulative particle size distribution curve obtained by measuring the particle size of the above-mentioned conductive particles using laser diffraction scattering, the particle size D with a cumulative frequency of 50% is... 50 The range is 0.5~100μm.

[0051] 12.

[0052] According to any one of the methods for manufacturing a substrate having a conductive pattern as described in 1. to 11, wherein,

[0053] In the pressing process described above, after covering the exposed surface of the transfer pattern with the component, pressure is applied to the transfer pattern at least once.

[0054] 13.

[0055] According to any one of the methods for manufacturing a substrate having a conductive pattern as described in 1. to 12, wherein,

[0056] The aforementioned easily peelable substrate is a resin film or release paper.

[0057] 14.

[0058] According to any one of the methods for manufacturing a substrate having a conductive pattern as described in 1. to 13, wherein,

[0059] Prior to the pressing process described above, there is a peeling process that peels off the easily peelable substrate.

[0060] 15.

[0061] A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 14, wherein,

[0062] The aforementioned substrate is flexible.

[0063] 16.

[0064] According to any one of the methods for manufacturing a substrate having a conductive pattern as described in 1. to 15, wherein,

[0065] The aforementioned substrate is selected from at least one of the group consisting of polyester, polyolefin and polycarbonate.

[0066] 17.

[0067] According to any one of the methods for manufacturing a substrate having a conductive pattern as described in 1. to 15, wherein,

[0068] The substrate is polyimide.

[0069] 18.

[0070] According to any one of the methods for manufacturing a substrate having a conductive pattern as described in 1. to 15, wherein,

[0071] The aforementioned substrate is paper.

[0072] 19.

[0073] According to any one of the methods for manufacturing a substrate having a conductive pattern as described in 1. to 18, wherein,

[0074] The thickness of the adhesive layer is 1~30μm.

[0075] 20.

[0076] According to any one of the methods for manufacturing a substrate having a conductive pattern as described in 1. to 19, wherein,

[0077] The height of the above provisional pattern is 0.5~100μm.

[0078] twenty one.

[0079] A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 20, wherein,

[0080] In the above transfer process, a pressing action is performed to improve the adhesion between the provisional pattern and the adhesive layer.

[0081] twenty two.

[0082] A method for manufacturing an electronic device, comprising manufacturing an electronic device using a substrate having a conductive pattern obtained by any one of the methods described in 1. to 21.

[0083] twenty three.

[0084] According to the manufacturing method of the electronic device described in 22, wherein,

[0085] The aforementioned electronic device is an RF tag.

[0086] twenty four.

[0087] A method for manufacturing an electromagnetic wave shielding film, comprising manufacturing an electromagnetic wave shielding film using a substrate having a conductive pattern obtained by any one of the methods described in 1. to 21.

[0088] 25.

[0089] A method for manufacturing a planar heating element, wherein the planar heating element is manufactured using a substrate having a conductive pattern obtained by the method for manufacturing a substrate having a conductive pattern as described in any one of 1. to 21.

[0090] 26.

[0091] An article for manufacturing a substrate having a conductive pattern, comprising:

[0092] Substrate;

[0093] A cured adhesive layer is a cured material disposed on the surface of the aforementioned substrate, which is a cured product of a material having at least one property of photocurability or thermosetting; and

[0094] The pattern is formed on the surface of the cured adhesive layer by means of a conductive composition containing conductive particles.

[0095] 27.

[0096] According to item 26, among which,

[0097] The amount of resin component in the above pattern is 15 parts by mass or less relative to 100 parts by mass of the above conductive particles.

[0098] 28.

[0099] According to the items recorded in 26 or 27, among which,

[0100] The above pattern, apart from the aforementioned conductive particles, does not actually contain any curable components.

[0101] 29.

[0102] According to any one of the items recorded in 26.~28, among which,

[0103] In the volume-based cumulative particle size distribution curve obtained by measuring the particle size of the above-mentioned conductive particles using laser diffraction scattering, the particle size D with a cumulative frequency of 50% is... 50 The range is 0.5~100μm.

[0104] 30.

[0105] According to any one of the items recorded in 26.~29, among which,

[0106] The aforementioned substrate is flexible.

[0107] 31.

[0108] According to any one of the items recorded in 26.~30, among which,

[0109] The aforementioned substrate is selected from at least one of the group consisting of polyester, polyolefin and polycarbonate.

[0110] 32.

[0111] According to any one of the items recorded in 26.~30, among which,

[0112] The substrate is polyimide.

[0113] 33.

[0114] According to any one of the items recorded in 26.~30, among which,

[0115] The aforementioned substrate is paper.

[0116] 34.

[0117] According to any one of the items recorded in 26.~33, among which,

[0118] The thickness of the above-mentioned cured adhesive layer is 1~30μm.

[0119] 35.

[0120] According to any one of the items recorded in 26.~34, among which,

[0121] A portion of the aforementioned cured adhesive layer is cured while immersed in the gaps between the conductive particles within the aforementioned pattern.

[0122] According to the present invention, when a conductive pattern is formed on a substrate using a conductive composition containing conductive particles, the adhesion of the conductive pattern is improved. Attached Figure Description

[0123] Figure 1 This is a diagram illustrating a method for manufacturing a substrate with conductive patterns.

[0124] Figure 2 This is a diagram illustrating a method for manufacturing a substrate with conductive patterns.

[0125] Figure 3 This is a diagram used to illustrate the shape of the conductive pattern formed in the embodiments.

[0126] Figure 4 It is an electron microscope image of a cross-section of a substrate with a conductive pattern manufactured in Example I-1.

[0127] Figure 5 This is an electron microscope image of a cross-section of a substrate with a conductive pattern manufactured in Example II-1. Detailed Implementation

[0128] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0129] In all the accompanying drawings, the same reference numerals are used to label the same constituent elements, and descriptions are omitted where appropriate.

[0130] To avoid complexity, the following situations exist: (i) when multiple identical constituent elements exist in the same drawing, only one of them is labeled with a reference numeral, instead of labeling all constituent elements; (ii) especially in Figure 2 After that, there will be no more confrontation with Figure 1 The same constituent elements are relabeled with reference numerals.

[0131] All accompanying drawings are for illustrative purposes only. The shapes, dimensions, etc., of the components in the drawings may not correspond to the actual items.

[0132] In this specification, the designation "X~Y" in the description of numerical ranges means above X and below Y, unless otherwise stated. For example, "1~5% by mass" means "more than 1% by mass and less than 5% by mass".

[0133] In the description of groups (atomic groups) in this specification, the description of whether a group is substituted or unsubstituted includes both cases with and without a substituent. For example, "alkyl" includes not only unsubstituted alkyl groups (unsubstituted alkyl groups) but also substituted alkyl groups (substituted alkyl groups).

[0134] The designation "(meth)acrylic acid" in this specification includes both acrylic acid and methacrylic acid. The same applies to designations such as "(meth)acrylate".

[0135] The term "organic group" in this specification, unless otherwise stated, refers to a group of atoms obtained by removing one or more hydrogen atoms from an organic compound. For example, "monovalent organic group" means a group of atoms obtained by removing one hydrogen atom from any organic compound.

[0136] For the purposes of this specification, the term "electronic device" is used to include semiconductor chips, semiconductor components, printed wiring substrates, circuit display devices, information communication terminals, light-emitting diodes, physical batteries, chemical batteries, and other components, devices, and final products that utilize electronic engineering technology.

[0137] <Method for manufacturing a substrate with conductive patterns>

[0138] The method for manufacturing a substrate with a conductive pattern according to this embodiment includes: a transfer process in which a provisional pattern disposed on the surface of an easy-to-peel substrate by means of a conductive composition containing conductive particles is brought into contact with an adhesive layer disposed on the surface of a substrate different from the easy-to-peel substrate, thereby obtaining a transfer pattern in which the provisional pattern is transferred to the surface of the adhesive layer; and a pressing process in which at least pressure is applied to the transfer pattern to obtain a conductive pattern.

[0139] In this embodiment, the transfer pattern containing conductive particles is pressed onto the adhesive layer rather than the substrate itself. Therefore, the resulting conductive pattern exhibits good adhesion.

[0140] In conventional conductive pattern formation, conductive components containing conductive particles are often patterned onto a substrate using printing methods such as screen printing and inkjet printing. However, these printing methods are inherently difficult to apply high "pressure" to the conductive components during printing. In contrast, as in this embodiment, when pattern printing is performed using a "transfer" method on an easily peelable substrate, greater "pressure" can be applied to the conductive components during printing. This greater pressure is considered beneficial for improving adhesion. That is, in this embodiment, adhesion is not improved simply by providing an adhesive layer, but also by combining the provision of an adhesive layer with the use of a transfer method that applies high pressure during pattern formation, resulting in particularly good adhesion of the conductive pattern.

[0141] Furthermore, by immersing a portion of the adhesive layer into the gaps between the conductive particles in the transfer pattern, the adhesion of the conductive pattern may become particularly good.

[0142] Furthermore, due to the pressing process, conductive particles in the transferred pattern may sinter. Therefore, the resulting conductive pattern often exhibits good conductivity.

[0143] Furthermore, it can be considered that the pattern is not formed by directly coating or printing the conductive components onto the substrate, but by using a "transfer" method to form the pattern, which can create finer and more precise conductive patterns.

[0144] The following is for reference Figure 1 and Figure 2 This embodiment will be described in more detail.

[0145] (Formation of provisional patterns on the surface of easily peelable substrates:) Figure 1 P1, Figure 1 P2)

[0146] In this embodiment, a provisional pattern can be formed on the surface of an easily peelable substrate using a conductive composition containing conductive particles.

[0147] Specifically, firstly, such as Figure 1 As shown in P1, a pattern 3 is formed on the surface of the easily peelable substrate 5. This pattern 3 is typically formed from a conductive composition containing a solvent, a paste-like substance, and conductive particles. Then, by evaporating the solvent in the pattern 3, as... Figure 1 As shown in P2, a provisional pattern (pattern 3B) can be obtained on the easily peelable substrate 5.

[0148] There are no particular limitations on the method of forming pattern 3. Various coating and printing techniques can be applied. Pattern 3 can be set on the entire surface of one side of the easily peelable substrate 5, or it can be set only on a portion of one side of the easily peelable substrate 5. In the former case, pattern 3 can be formed by coating using devices such as blade coaters, air knife coaters, doctor blade coaters, roller coaters, bar coaters, and curtain coaters. In the latter case, pattern 3 can be formed by various printing methods such as screen printing, gravure printing, letterpress printing, offset printing, inkjet printing, and transfer printing. By appropriately designing the "pattern" during printing, a substrate with a pattern structure that ultimately functions as a conductive film (circuit pattern) or a mesh pattern with electromagnetic wave shielding capabilities can be manufactured. When pattern 3 is set only on a portion of one side of the easily peelable substrate 5, it is preferable to appropriately design the printed "pattern" according to the intended use of the substrate with the final conductive pattern.

[0149] To prevent the pattern 3 from forming in a location other than the desired location on the peelable substrate 5, for example, a perforated film can be placed on the peelable substrate 5, and a conductive composition can be coated or printed on it, and then the film can be removed.

[0150] For the easily peelable substrate 5, there are no particular limitations as long as it can be easily peeled off in the peeling process described later, that is, the provisional pattern (pattern 3B) can be easily separated.

[0151] Specifically, resin films can be cited as an example of an easy-to-peel substrate 5. More specifically, resin films coated with silicone resin or resin films compounded with silicone resin can be cited. The main material of these resin films is not particularly limited, but polyester-based materials are preferred, and polyethylene terephthalate is more preferred, considering strength and cost. In addition, various films commercially available under names such as "release film" or "peel-off film" can also be used as easy-to-peel substrate 5.

[0152] In addition, release paper can also be used as an easy-to-peel substrate. Typically, release paper refers to laminated paper in which a thin film of resin is layered on top to impart easy-to-peel properties. Release paper is sometimes also called peeling paper. Various commercially available release papers can also be used appropriately.

[0153] The easily peelable substrate 5 can be Figure 1 P1 or Figure 1 The substrate 5 can be in the form of a film or sheet as shown in P2, but it can also be, for example, in the form of a roller. For example, a roller with a surface material of metal or resin, capable of forming a provisional pattern on the surface and easily separating the provisional pattern, can be used as the easy-to-peel substrate 5. By using the roller-shaped easy-to-peel substrate 5, it is expected that the production rate of substrates with conductive patterns will be improved.

[0154] The easy-to-peel substrate 5 can be disposable or reusable.

[0155] The surface of the easy-peel substrate 5 is typically flat. The surface of the easy-peel substrate 5 typically does not have recesses or protrusions. The easy-peel substrate 5 is typically not a gravure or relief plate.

[0156] When the easily peelable substrate 5 is in the form of a film or sheet, its thickness is not particularly limited. Considering the operability and transfer accuracy of the easily peelable substrate 5, it is preferably 10~250μm, and more preferably 10~100μm.

[0157] The heating conditions used to evaporate the solvent in pattern 3 to obtain the provisional pattern (pattern 3B) can be set, for example, to 50-150°C for 1-60 minutes. However, regarding the temperature, it is preferable to set it to a temperature that will not damage the easily peelable substrate 5. For heating, as an example, heating can be performed by blowing hot air onto pattern 3; as another example, heating can be performed by placing the easily peelable substrate 5 and pattern 3 on a hot plate. As yet another example, heating can also be performed by light. Specifically, examples include heating using a far-infrared heating furnace (IR oven), Adphos NIR (ultra-near-infrared) heating, heating based on high-brightness LEDs, and laser heating.

[0158] The height of the provisional pattern (pattern 3B) is preferably 0.5 to 100 μm, more preferably 5 to 60 μm, and even more preferably 10 to 40 μm. By making this height 0.5 μm or more, the conductivity of the final conductive pattern can be improved. On the other hand, by making this height 100 μm or less, the substrate having the final conductive pattern can be made thinner overall. This is preferred from the viewpoint of miniaturization and weight reduction of electronic devices, for example.

[0159] The conductive particles in the provisional pattern (pattern 3B) are preferably not substantially sintered. Furthermore, in this embodiment, the conductive particles are typically sintered during the pressing process described later.

[0160] Furthermore, the provisional pattern (pattern 3B) is preferably not substantially cured. Specifically, even if the conductive component contains curable resin, crosslinking agent, etc., it is preferable that the curable resin and crosslinking agent in the provisional pattern (pattern 3B) are not substantially reacted before the transfer process.

[0161] For the conductive composition used to form the provisional pattern (pattern 3B), it is preferable to be in a paste form at room temperature for ease of pattern formation.

[0162] From the viewpoint of further improving the conductivity of the final conductive pattern, the amount of resin component in the conductive composition 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, relative to 100 parts by mass of conductive particles. Furthermore, the remaining components in the conductive composition are preferably conductive particles. The conductive composition may also be resin-free, provided that pattern formation is not problematic. From the viewpoint of improving conductivity, the conductive composition preferably contains substantially no curable components other than the conductive particles.

[0163] On the other hand, from the viewpoint of improving the pattern-forming properties, i.e., the printability and coating properties of the conductive composition, the conductive composition may also contain resin components such as resin and adhesive. From the viewpoint of fully obtaining the effects obtained by using resin components, the amount of resin component in the conductive composition 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, relative to 100 parts by mass of conductive particles. Furthermore, the remaining components in the conductive composition are preferably conductive particles.

[0164] In particular, when the final conductive pattern is applied to a paper substrate, the amount of resin component can be relatively large, considering that the resin component will penetrate into the paper substrate. In this case, the amount of resin component in the conductive composition is preferably 5 to 30 parts by mass, more preferably 10 to 20 parts by mass, relative to 100 parts by mass of conductive particles.

[0165] Resin components that can be contained as conductive components include, in particular, polyvinylpyrrolidone, polyester, epoxy resin, (meth)acrylic resin, polyvinyl acetal, cellulose resin (e.g., ethyl cellulose), phenolic resin, etc.

[0166] Conductive compositions can contain solvents. By including solvents in conductive compositions, the coatability or printability of the conductive composition to a substrate is improved. Typically, solvents contain organic solvents. Solvents can also contain water, provided that the conductive particles can be properly dispersed.

[0167] There are no particular restrictions on the type of solvent. Any solvent can be a substance that does not substantially alter the composition of the conductive material.

[0168] The amount of solvent used can be adjusted appropriately according to the coating and printing methods of the conductive component. The amount of solvent used in the total conductive component is, for example, 3 to 30% by mass, preferably 5 to 25% by mass, and more preferably 10 to 20% by mass.

[0169] Regarding the conductive particles contained in the conductive composition, from the viewpoint of easy availability and good conductivity, it is preferable to include at least one element selected from the group consisting of silver and copper.

[0170] 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, "primarily composed of silver" means that the proportion of silver in all the constituent elements of the particles is preferably 50 mol% or more, more preferably 75 mol% or more, further preferably 90 mol% or more, and particularly preferably 95 mol% or more. Similarly, "primarily composed of copper" means that the proportion of copper in all the constituent elements of the particles is preferably 50 mol% or more, more preferably 75 mol% or more, further preferably 90 mol% or more, and particularly preferably 95 mol% or more.

[0171] It should be noted that conductive particles can contain elements other than silver and copper, as long as the desired conductivity can be achieved. Examples of elements other than silver and copper include gold, aluminum, platinum, palladium, iridium, tungsten, nickel, tantalum, lead, and zinc.

[0172] Conductive particles can contain two or more elements. For example, in this embodiment, conductive particles with silver plating on the surface of copper particles (silver-plated copper particles) are preferably used. Silver-plated copper particles are particles with copper as the main component, for example, with silver plating on the surface of copper particles in an amount of up to 35% by mass based on the total mass of the particles.

[0173] In the volume-based cumulative particle size distribution curve obtained by measuring the particle size of conductive particles using laser diffraction scattering, the particle size D with a cumulative frequency of 50% is... 50 Preferably, the micrometer is 0.5~100μm, more preferably 0.6~50μm, even more preferably 0.7~30μm, and particularly preferably 0.7~20μm.

[0174] By making D 50 A sufficiently large size can reduce the number of grain boundaries between conductive particles per unit volume. This is believed to contribute to a lower resistivity in the resulting conductive pattern.

[0175] By not making D 50 If the size is too large, the "gap" between conductive particles becomes smaller, which is believed to help to make the resistivity of the resulting conductive pattern lower.

[0176] Furthermore, by making D 50 For an appropriate value, it is assumed that a portion of the adhesive layer 2 can easily penetrate into the gaps between the conductive particles in the provisional pattern (pattern 3B). That is, D 50 An appropriate value is also considered to help further improve adhesion. For nanoscale conductive particles, the adhesive layer 2 does not easily penetrate into the gaps between the conductive particles.

[0177] Conductive particles can be purchased from companies such as DOWA ELECTRONICS and Fukuda Metal Foil Powder Industry Co., Ltd. Two or more different conductive particles can also be mixed for purposes such as adjusting or optimizing particle size distribution.

[0178] From the viewpoint of further reducing the resistivity of the final conductive pattern, it is preferable to have a higher proportion of conductive particles in the conductive composition. Specifically, the proportion of conductive particles in all non-volatile components of the conductive composition is preferably 95% by mass or more, more preferably 97% by mass or more, further 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 obtained conductive pattern, the conductive composition is preferably substantially free of resin components such as resin and adhesive. Here, "substantially free" means completely free of resin components or, although containing resin components, in such small amounts that the desired effect of using resin components cannot be obtained (for example, 1% by mass or less, specifically 0.5% by mass or less in all non-volatile components of the conductive composition). If the desired conductive pattern can be obtained, the conductive composition may also be free of resin and adhesive.

[0179] The conductive composition may or may not contain other conventional ink compositions or various additives found in conductive pastes.

[0180] (Formation of the adhesive layer on the substrate:) Figure 1 A)

[0181] Figure 1 In the figure, A represents an adhesive layer 2 provided on the surface of a substrate 1 that is different from the easily peelable substrate 5.

[0182] Substrate 1 is typically in the form of a film, sheet, or plate. From an industrial productivity point of view, the shape of substrate 1 is preferably any of these.

[0183] The substrate 1 is preferably flexible. By using a flexible substrate 1, flexible printed circuit boards (FPCs) can be manufactured. Using a flexible substrate 1 facilitates the pressing process using rollers in the pressing process described later. This is preferred from a mass production point of view. It should be noted that the substrate 1 can also be a rigid substrate without flexibility.

[0184] The thickness of substrate 1 is not particularly limited and can be appropriately set according to the end application (electronic devices, RF tags, electromagnetic wave shielding films, planar heating elements, etc.) and various other situations. The thickness of substrate 1 is typically 10-250 μm, preferably 30-100 μm. However, from the viewpoint of suppressing curling caused by shrinkage during the curing of adhesive layer 2, substrate 1 preferably has a certain thickness. Specifically, the thickness of substrate 1 is preferably 100-250 μm, more preferably 100-150 μm.

[0185] The substrate 1 can be a single-layer structure or a multi-layer structure with two or more layers.

[0186] Considering cost and end use, substrate 1 is preferably selected from at least one of the following groups: polyesters such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate), polyolefins such as polyethylene or polypropylene, polycarbonate, polyimide, and paper. Here, the paper can be coated paper (paper with a coating agent applied to its surface) or ordinary paper without coating. Furthermore, substrate 1 is not limited to PET; a general resin film can be used. Additionally, substrate 1 can be transparent or opaque. Examples of opaque resin films include foamed resin films such as foamed PET films or foamed resin sheets.

[0187] In this embodiment, a conductive pattern with sufficiently low resistivity can be obtained even without heating or at a relatively low temperature during the pressing process. Therefore, a substrate 1 with low heat resistance, such as polyester, polyolefin, polycarbonate, or paper, can preferably be used as the substrate. Furthermore, when a substrate 1 with high heat resistance, such as polyimide, is used, the resistivity of the resulting conductive pattern can be further reduced by performing high-temperature heating during the pressing process.

[0188] The adhesive layer 2 preferably has thermosetting or photocurable properties. More preferably, the adhesive layer 2 is formed of a thermosetting resin material or a photocurable resin material. When the substrate 1 is translucent, by making the adhesive layer 2 photocurable, the adhesive layer 2 can be cured by irradiating it with light from the substrate 1 side. When the substrate 1 is opaque, by making the adhesive layer 2 thermosetting, the adhesive layer 2 can be cured by heating.

[0189] It should be noted that the adhesive layer 2 can have both thermosetting and photocurable properties, or it can have only one of the thermosetting or photocurable properties.

[0190] Various thermosetting or photocurable resin materials can be cited as materials constituting the adhesive layer 2. Specifically, thermosetting or photocurable resin materials such as epoxy resin, polymeric (meth)acrylate, polyurethane, polyurethane (meth)acrylate, and silicone are examples.

[0191] The adhesive layer 2 can also be made of commercially available products. For example, various thermosetting or photocurable resin materials known or commercially available as hard coating agents can be used to form the adhesive layer 2. In addition, various thermosetting or photocurable resin materials known or commercially available as primers can also be used.

[0192] When the adhesive layer 2 is thermosetting, it is preferable to form the adhesive layer 2 by thermosetting at a temperature that will not damage the substrate 1. For example, when the substrate 1 is made of resin, it is preferable to design the adhesive layer 2 by heating at a temperature below the glass transition temperature of the resin to allow the curing reaction to proceed sufficiently.

[0193] exist Figure 1 In stage A, adhesive layer 2 is preferably in an uncured or semi-cured state, more preferably in an uncured state. It is believed that by leaving the adhesive layer in an uncured or semi-cured state, a portion of adhesive layer 2 can be immersed into the gaps between the conductive particles in the provisional pattern (pattern 3B) during the transfer process described later. This is considered to help further improve the adhesion of the final conductive pattern.

[0194] The thickness of the adhesive layer 2 is not particularly limited, but considering the need to obtain sufficient adhesion and properly control the immersion into the provisional pattern, it is preferably 1 to 30 μm, and more preferably 5 to 15 μm.

[0195] The adhesive layer 2 can be a single layer or two or more layers. For example, when the substrate 1 is paper, considering the penetration into the fibrous paper, a two-layer adhesive layer 2 can be used. In this case, the adhesive layer closest to the first layer of paper acts as a "sealing" layer.

[0196] (Transfer process:) Figure 2 B)

[0197] In the transfer process, make Figure 1 The provisional pattern (pattern 3B) shown in P2 comes into contact with the adhesive layer 2 disposed on the surface of the substrate 1. Thus, the provisional pattern (pattern 3B) is transferred to the surface of the adhesive layer 2, thereby obtaining the transfer pattern (pattern 3B).

[0198] In the transfer process, pressing may or may not be performed to improve the adhesion between the provisional pattern (pattern 3B) and the adhesive layer 2. Pressing can be performed or not, as long as the provisional pattern (pattern 3B) is properly separated from the easily peelable substrate 5 at an appropriate stage. When pressing is performed, care should be taken to avoid altering the shape of the provisional pattern (pattern 3B). From the viewpoint of improving adhesion, pressing is generally preferred. Incidentally, in the embodiments described later, after the provisional pattern comes into contact with the adhesive layer, pressing is performed using a roller from the easily peelable substrate 5 side. Besides using a roller, pressing with a flatbed press is also considered.

[0199] When adhesive layer 2 is uncured or semi-cured, it is believed that a portion of adhesive layer 2 will penetrate into the gaps between the conductive particles in the provisional pattern (pattern 3B) during this transfer process. This is considered to help further improve the adhesion of the final conductive pattern.

[0200] (Adhesive layer curing process:) Figure 2 C)

[0201] In this embodiment, it is preferable to perform an adhesive layer curing process between the transfer process and the pressing process, in which the adhesive layer 2 is cured. As a result, the adhesion between the provisional pattern (pattern 3B) and the cured adhesive layer 2B tends to be further improved after the adhesive layer 2 is cured.

[0202] Regarding the curing of adhesive layer 2, when adhesive layer 2 has photocurability, it can be cured by light such as ultraviolet light. Furthermore, when adhesive layer 2 has thermosetting properties, it can be cured by heating. Figure 2 C illustrates a method of curing the adhesive layer 2 by irradiating it with ultraviolet (UV) light from the transparent substrate 1 side. The conditions of light irradiation and heating can be appropriately adjusted and optimized according to the specific materials constituting the adhesive layer 2. However, when curing the adhesive layer 2 by heating, care should be taken to prevent damage to the substrate 1 due to heat.

[0203] In the adhesive layer curing process, it is preferable to fully cure the adhesive layer 2, but it is also permissible to cure it to a certain extent rather than fully curing it. In any case, the goal is to improve the adhesion between the provisional pattern (pattern 3B) and the cured adhesive layer 2B after the adhesive layer 2 has been cured.

[0204] (Stripping process:) Figure 2 D)

[0205] Prior to the pressing process described later, it is preferable to perform a peeling process to peel the easily peelable substrate 5 from the pattern 3B.

[0206] It should be noted that, in Figure 2In this context, the peeling process is described as occurring between the adhesive layer curing process (C) and the oxide film removal process (E). However, as long as a substrate with the desired conductive pattern can be obtained in the end, the peeling process can also be performed between the transfer process (B) and the adhesive layer curing process (C).

[0207] There are no particular limitations on the specific method and conditions of peeling, as long as the easily peelable substrate 5 can be properly peeled off from pattern 3B.

[0208] (Oxide film removal process:) Figure 2 E)

[0209] In this embodiment, it is preferable to perform the oxide film removal process, which involves bringing component X, capable of removing the oxide film from the surface of the conductive particles, into contact with the oxide film in the transfer pattern (pattern 3B), after the transfer process and before or simultaneously with the pressing process described later. By performing the oxide film removal process, the sintering of the conductive particles is easier to perform in the pressing process described later, and the conductivity of the final conductive pattern tends to be further improved.

[0210] Component X preferably penetrates into the interior of the transfer pattern (pattern 3B) through the gaps between the conductive particles constituting the transfer pattern (pattern 3B). This tends to further improve the conductivity of the final conductive pattern. Therefore, during the oxide film removal process, the transfer pattern (pattern 3B) in contact with component X can also be pressed to promote the penetration of component X into the interior of the transfer pattern (pattern 3B). In this case, the oxide film removal process and the pressing process described later are sometimes performed simultaneously.

[0211] Of course, the oxide film removal process can also be performed as a different process from the pressing process.

[0212] The oxide film removal process can be, for example, as follows: Figure 2 As shown in E, the process is carried out by contacting and preferably penetrating a liquid 7 containing a component X of an oxide film capable of removing conductive particles into the transfer pattern (pattern 3B). Figure 2 E shows a method of dripping or spraying liquid 7 containing component X onto the transfer pattern (pattern 3B), but the transfer pattern (pattern 3B) can also be immersed in the liquid containing component X. Alternatively, the liquid 7 containing component X can be brought into contact with the embedded pattern (pattern 3B) by inkjet printing or dispensing.

[0213] As a liquid containing component X, water in which component X is dissolved or dispersed is preferred. Using water is preferred in terms of reducing environmental impact and process safety (non-flammability). Of course, organic solvents in which component X is dissolved or dispersed can also be used.

[0214] As an alternative to using a liquid containing component X, the oxide film removal process can also be performed by contacting component X in a gaseous state with the transfer pattern (pattern 3B).

[0215] Furthermore, it is also considered to bring the sheet containing component X into contact with pattern 3B, preferably by applying pressure, so that component X penetrates into pattern 3B. Specifically, examples of the sheet containing component X include paper, nonwoven fabric, resin sheets coated or printed with component X, etc.

[0216] Furthermore, there are no particular limitations on the method by which component X comes into contact with and penetrates into the transfer pattern (pattern 3B).

[0217] There are no particular limitations on component X as long as it can remove the oxide film on the surface of conductive particles.

[0218] In this specification, “removal” of oxide film includes not only the removal of oxides present on the surface of conductive particles, but also the removal of oxides from their original state through chemical changes such as reduction.

[0219] According to the inventors' knowledge, it is preferred to include at least one of the group consisting of organic acids, oxyacids of phosphorus, and hydrazine or its derivatives. These are particularly preferred when the conductive particles contain copper or silver.

[0220] Examples of organic acids include citric acid, formic acid, acetic acid, malonic acid, malic acid, tartaric acid, ascorbic acid, succinic acid, fumaric acid, and propionic acid.

[0221] Examples of oxyacids of phosphorus include hypophosphoric acid, phosphonic acid, phosphorous acid, phosphoric acid, diphosphoric acid, triphosphoric acid, and trimetaphosphoric acid. Hypophosphoric acid is particularly preferred.

[0222] Examples of hydrazine or its derivatives include hydrazine itself; hydrazine salts such as hydrazine hydrochloride, hydrazine dihydrochloride, hydrazine hydrobromide, and hydrazine sulfate; and other compounds with the -NH-NH2 structure.

[0223] Furthermore, from the viewpoint of removing oxide films, compounds with low pKa values ​​in water can be used as component X. Specifically, compounds with pKa values ​​of -5.0 to 5.0 in water are preferably used as component X, and compounds with pKa values ​​of -4.0 to 4.5 are more preferably used as component X. In addition, when component X is a polybasic acid, it is preferable that the smallest pKa among the plurality of pKa values ​​is within the above-mentioned range.

[0224] If only the small pKa and its resulting oxide film removal are considered, inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid can also be used as component X. However, considering the undesirable conditions when it remains in pattern 3B, an organic acid is preferred as component X.

[0225] Furthermore, the pKa value here can be a value at room temperature (e.g., 25°C). However, from the viewpoint of oxide film removal in actual processes, it is preferable to use the pKa value at the temperature of the permeation process or the conductive film formation process.

[0226] Furthermore, as component X, any compound capable of restoring the oxide film to a non-oxidized state through a reduction reaction can be used. For example, compounds with aldehyde groups can sometimes reduce oxides and therefore can be used as component X.

[0227] Furthermore, as component X, it is preferable to use a compound with a low pKa in water that can restore the oxide film to a non-oxidized state through a reduction reaction. Formic acid is an example of such a compound. Formic acid has the advantage of being easily volatile and therefore not easily remaining in the pattern.

[0228] In addition to the above, other possible components X include pyrogallol, phenidone, hydroquinone, and o-aminophenol. These are substances known to function as reducing agents in the field of silver halide photography.

[0229] When comparing the case where compound A is infiltrated into pattern 3B with the case where it is not infiltrated into pattern 3B, if the former yields a conductive pattern with lower resistivity, then compound A can be used as component X.

[0230] When the liquid containing dissolved or dispersed component X comes into contact with pattern 3B, the concentration of component X in the liquid can be adjusted appropriately. The concentration can be adjusted based on the viewpoint of ensuring sufficient amount of component X penetrates into pattern 3B and reducing the amount of residual component X to suppress corrosion and deterioration of the conductive pattern.

[0231] 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, liquids containing component X at concentrations lower than those shown herein, or liquids containing component X at concentrations higher than those shown herein (e.g., saturation concentration), can also be used.

[0232] Preferably, when performing the oxide film removal process, specifically after the stripping process and before the oxide film removal process, the transfer pattern (pattern 3B) is pressed at least once. This makes it easier to maintain the shape of the transfer pattern (pattern 3B) during the oxide film removal process. In particular, when a liquid containing dissolved or dispersed component X is allowed to penetrate into the transfer pattern (pattern 3B) during the oxide film removal process, it is easier to prevent at least a portion of the transfer pattern (pattern 3B) from deforming or disintegrating due to the liquid. Especially when using a conductive composition that is substantially free of resin components, the transfer pattern (pattern 3B) is prone to deformation and disintegration, so pressing as described here is preferable. In other words, when using a conductive composition containing resin components, the transfer pattern (pattern 3B) is less prone to deformation and disintegration compared to using a conductive composition that is substantially free of resin components, and therefore, sometimes the shape of the transfer pattern (pattern 3B) can be adequately maintained even without pressing.

[0233] When the transfer pattern (pattern 3B) is pressed before the oxide film removal process, the method can be, for example, according to the pressing process described later. Figure 2 The process should proceed as described in F). However, it is preferable to adjust the pressure appropriately. From the viewpoint of maintaining the shape of the transfer pattern (pattern 3B), a higher pressure is preferred. However, from the viewpoint of the permeability of component X, since there are preferably appropriate gaps between the conductive particles, it is preferable that the pressure is not too high.

[0234] Specifically, when the pressure applied to the transfer pattern (pattern 3B) during the pressing process before the oxide film removal process is set to P... first The pressure applied to the transfer pattern (pattern 3B) in the conductive film formation process described later will be set as P. second When, P is preferred first < P second More specifically, P first P is preferred second The pressure is preferably 0.9 times or less, more preferably 0.75 times or less, and even more preferably 0.6 times or less. That is, the pressure in the pressing process is preferably sufficiently less than the pressure required in the pressing process to compact the conductive particles or sinter them.

[0235] From various perspectives, P is both optimized and preferred. first and P second Their respective values.

[0236] P first Preferably, it is 1~500 MPa, more preferably 10~200 MPa, and even more preferably 20~100 MPa. By making P... firstWith a pressure of 1 MPa or higher, it is easy to reliably and sufficiently achieve the effect of maintaining the shape of the transfer pattern (pattern 3B) in subsequent processes. Furthermore, by making P... first At pressures below 500 MPa, the "gap" for the penetration of component X is easily and fully retained in the transfer pattern (pattern 3B).

[0237] Additionally, P second As an example, the pressure is 1 MPa or more, preferably 10 MPa or more, more preferably 10 to 5000 MPa, further preferably 20 to 1000 MPa, particularly preferably 30 to 300 MPa, and especially preferably 50 to 250 MPa. By making P second A sufficiently large pressure value can further reduce the resistivity of the final conductive pattern. Furthermore, by ensuring the pressure is not excessive, damage to the substrate 1 and the transferred pattern (pattern 3B) can be suppressed. Incidentally, if the strength of the substrate 1 is sufficient, the pressure can be increased to further reduce the resistivity of the final conductive pattern.

[0238] Alternatively, during the oxide film removal process, a treatment can be performed to reduce the amount of component X remaining in the transfer pattern (pattern 3B). This treatment further reduces the resistivity of the final conductive pattern. This treatment can be performed before or after the pressing process described below.

[0239] As an example, when component X has the property of volatilizing by heating, consider performing a process to volatilize component X remaining in the transfer pattern (pattern 3B) by heating the transfer pattern (pattern 3B) to an appropriate temperature.

[0240] As another example, consider a treatment that dissolves component X remaining in the transfer pattern (pattern 3B) by bringing the transfer pattern (pattern 3B) into contact with a liquid such as water.

[0241] More specifically, as a treatment to reduce the amount of component X remaining in the transfer pattern (pattern 3B), the following methods (i) to (v) can be cited.

[0242] (i) Blow airflow onto the transfer pattern (pattern 3B).

[0243] (ii) Inert gas such as nitrogen is sprayed onto the transfer pattern (pattern 3B).

[0244] (iii) By pressing a liquid-absorbing component such as a sponge onto the transfer pattern (pattern 3B), the solution or dispersion containing component X is absorbed. Figure 2In the continuous process shown, a roller sponge is preferably used as the liquid-absorbing component. Alternatively, after absorbing the solution or dispersion, the transfer pattern (pattern 3B) is brought into contact with a liquid such as water (cleaning), and then the liquid-absorbing component is pressed onto the transfer pattern (pattern 3B) again.

[0245] (iv) By applying pressure to the transfer pattern (pattern 3B) using rollers, the solution or dispersion containing component X is "extruded". Afterwards, the transfer pattern (pattern 3B) can be brought into contact with a liquid such as water (cleaned), and then the liquid can be extruded again using rollers. Incidentally, by properly controlling the pressure and not heating while applying pressure, it is possible to extrude the solution or dispersion containing component X without sintering the conductive particles in the transfer pattern (pattern 3B).

[0246] (v) Combinations of two or more of (i) to (iv) above. For example, combinations of (i) and (ii), combinations of (iii) and (iv), etc.

[0247] (Pressing process:) Figure 2 F)

[0248] In the pressing process, pressure is applied to the transfer pattern (pattern 3B). This improves the conductivity of the transfer pattern (pattern 3B) and yields a conductive pattern 3C. Preferably, the conductive particles in the transfer pattern (pattern 3B) are sintered through the pressing process.

[0249] For pressurization, for example, Figure 2 As shown in Figure F, preferably after covering the exposed surface of the transfer pattern (pattern 3B) with component 6, pressure is applied to at least the transfer pattern (pattern 3B). Furthermore, as an example, pressure can be applied by conveying the laminate of substrate 1, cured adhesive layer 2B, transfer pattern (pattern 3B), and component 6 between two opposing rollers 10A and 10B while they are clamped together. Component 6 is preferably a film.

[0250] By the way, in Figure 2 In F, Figure 2 As described in E, liquid 7 containing component X, capable of removing the oxide film on the surface of conductive particles, exists in the upper part of the transfer pattern (pattern 3B). In this case, it is assumed that the sintering of the conductive particles occurs in parallel with the removal of the oxide film on the conductive particles by pressurizing component X to penetrate into the interior of the transfer pattern (pattern 3B). That is, Figure 2 E and F can also be interpreted as indicating a method of simultaneously performing the oxide film removal process and the pressing process.

[0251] There are several advantages to using component 6 when pressurizing. Examples of these advantages include the following.

[0252] It can suppress damage to roller 10A. In addition, it can sometimes suppress the situation where part or all of the transfer pattern (pattern 3B) peels off and adheres to roller 10A.

[0253] By avoiding direct contact between roller 10A and the transfer pattern (pattern 3B), it is easier to suppress unintended deformation and disintegration of the transfer pattern (pattern 3B).

[0254] By using component 6 as a "buffer material," pressure can be easily and evenly applied to the transfer pattern (pattern 3B). This helps, for example, increase the yield of the substrate having the final conductive pattern. Furthermore, when the oxide film removal process and the pressing process are performed simultaneously, applying pressure evenly to the transfer pattern (pattern 3B) is also preferred in that it helps to ensure that component X penetrates evenly into the transfer pattern (pattern 3B).

[0255] From one perspective, the material of component 6 can be the same as that of substrate 1. That is, component 6 can preferably be a polyester film such as PET film.

[0256] From another perspective, considering the need to suppress peeling and damage to the transferred pattern (pattern 3B), it is preferable to use an easy-to-peel film or release paper as component 6. Specific examples of easy-to-peel film or release paper include... Figure 1 The easily peelable substrate mentioned in the text 5.

[0257] From another perspective, component 6 could also be made of non-resin materials such as aluminum foil.

[0258] On the other hand, in order to simplify the manufacturing process and reduce waste by reducing the amount of materials used in the process, pressure can be applied without using component 6.

[0259] Figure 2 F illustrates a method of applying pressure to the transfer pattern (pattern 3B) using two opposing rollers 10A and 10B, but of course, pressure can also be applied to the transfer pattern (pattern 3B) using other methods. As an example, the laminate of substrate 1, cured adhesive layer 2B, transfer pattern (pattern 3B), and component 6 can be clamped between two flat plates and pressure applied (flatbed press). As another example, the laminate of substrate 1, cured adhesive layer 2B, transfer pattern (pattern 3B), and component 6 can be placed on a flat plate, and a roller can be placed against it from above, applying pressure to the transfer pattern (pattern 3B) while rolling the roller. As yet another example, the following method is also considered: the roller is placed against the substrate 1, cured adhesive layer 2B, transfer pattern (pattern 3B), and component 6 from below, applying pressure to the transfer pattern (pattern 3B) while rolling the roller.

[0260] In the pressing process, it is preferable to heat and press the transfer pattern (pattern 3B) simultaneously. As a result, the conductivity of the conductive pattern 3C tends to improve.

[0261] Preferably, the transfer pattern (pattern 3B) is pressed at a pressure of 1 to 5000 MPa and heated at a temperature of 50 to 400°C. More preferably, the transfer pattern (pattern 3B) is pressed at a pressure of 5 to 1000 MPa and heated at a temperature of 70 to 200°C. Even more preferably, the transfer pattern (pattern 3B) is pressed at a pressure of 10 to 300 MPa and heated at a temperature of 80 to 150°C. Additionally, the lower limit of the pressure can be 30 MPa or 50 MPa.

[0262] like Figure 2 As shown in F, when using two opposing rollers 10A and 10B for the pressing process, it is preferable to use rollers with built-in temperature-adjustable heaters.

[0263] There is no particular limitation on the pressing time. From the viewpoint of improved conductivity resulting from the thorough sintering of conductive particles and from the viewpoint of industrial productivity, an appropriate time can be adjusted and determined. The pressing time (the actual pressing time of the transfer pattern (pattern 3B)) is preferably 1 millisecond to 10 seconds, more preferably 10 milliseconds to 3 seconds, and even more preferably 30 milliseconds to 1 second. This value is particularly preferred when the transfer pattern (pattern 3B) is pressed using two opposing rollers 10A and 10B.

[0264] (Any other process)

[0265] The method for manufacturing a substrate with conductive patterns according to this embodiment may include steps other than those described above.

[0266] As an example, if component 6 is used in the pressing process, component 6 is removed after the pressing process is completed.

[0267] As another example, a removal process to remove component X remaining on or inside the obtained conductive pattern can be performed after the pressing process. Specifically, examples include immersing the obtained substrate with the conductive pattern in a liquid (water, organic solvent) capable of dissolving or dispersing component X, or rinsing the surface of the conductive pattern by applying a liquid (water, organic solvent) to it to remove residual component X. Alternatively, a process can be considered whereby the residual component X is vaporized and dispersed by heating the obtained substrate with the conductive pattern at a temperature that does not damage the substrate 1.

[0268] (Substrate with conductive patterns:) Figure 2 (G)

[0269] Through the series of processes described above, it is possible to manufacture Figure 2 The substrate with conductive patterns shown in G has a cured adhesive layer 2B on the surface of substrate 1, and a conductive pattern 3C is provided on the side of the cured adhesive layer 2B opposite to the side of substrate 1.

[0270] Conductive particles within the preferred conductive pattern 3C are sintered.

[0271] Preferably, the conductive pattern 3C and the cured adhesive layer 2B are not clearly separated, with a portion of the cured adhesive layer 2B immersed in the gaps between the conductive particles within the conductive pattern 3C. This approach is preferred from the viewpoint of further improving adhesion.

[0272] <Manufacturing Methods of Electronic Devices>

[0273] Electronic devices can be manufactured using the substrate with conductive patterns obtained as described above. By appropriately designing a provisional pattern, a substrate with conductive patterns (circuit patterns) capable of functioning as a circuit can be manufactured. Then, by combining this substrate with other electronic components, electronic devices can be manufactured.

[0274] Here are a few examples of electronic devices. It should be noted that electronic devices comprising a substrate with conductive patterns obtained by the manufacturing method of this embodiment are not limited to these examples.

[0275] • Sensors: For example, conductive components and circuits in sensors such as pressure sensors and vital signs sensors can be made using a substrate with a conductive pattern obtained by the manufacturing method of this embodiment.

[0276] • Solar cells: For example, for the current collection wiring of solar cells, a substrate with conductive patterns obtained by the manufacturing method of this embodiment can be used.

[0277] • Membrane switch: A membrane switch is a sheet-like switch in which circuitry and contacts are printed on the membrane and then overlapped and bonded together. To form its circuitry and contacts, the manufacturing method of the substrate with conductive patterns described in this embodiment can be applied.

[0278] • Touch sensors, touch panels: For example, the method for manufacturing a substrate with conductive patterns according to this embodiment can be used to form lead wires in touch sensors and touch panels. Additionally, the method for manufacturing a substrate with conductive patterns according to this embodiment is also considered for forming transparent electrodes in touch sensors and touch panels.

[0279] • Flexible substrate: Conventionally, a metal film is first coated onto the entire surface of a flexible film, and then unwanted portions of the metal film are removed using chemical agents to form a circuit. This conventional method is considered as an alternative to forming a circuit using a substrate with conductive patterns as described in this embodiment.

[0280] In particular, in electronic devices that conventionally use conductive paste to form circuits, by using the manufacturing method of this embodiment to form the circuit, the resistivity of the circuit can be reduced, and the performance of the electronic device can be expected to be improved.

[0281] RF tags are a particularly preferred electronic device. In other words, the method for manufacturing the conductive substrate described in this embodiment is preferred for manufacturing conductive circuits such as the antenna section in an RF tag.

[0282] For details regarding the specific structure of RF tags, please refer to Japanese Patent Application Publication No. 2003-332714 and Japanese Patent Application Publication No. 2020-46834.

[0283] <Manufacturing Method of Electromagnetic Wave Shielding Film>

[0284] As an application distinct from electronic devices, an electromagnetic wave shielding film can be manufactured using the method for manufacturing a substrate with conductive patterns according to this embodiment. Specifically, in the lamination process, an electromagnetic wave shielding film can be manufactured by setting the pattern when printing conductive components to a pattern specific to electromagnetic wave shielding films (e.g., a mesh pattern).

[0285] <Manufacturing Method of Planar Heating Element>

[0286] As another different application, consider manufacturing a planar heating element using the method for manufacturing a substrate with conductive patterns as described in this embodiment. A planar heating element is an object in which electrical wiring is provided on a substrate and heats up by allowing current to flow through the wiring. Specific examples of planar heating elements include planar heating elements used for anti-fogging and anti-cold purposes, such as those found in the rear window glass of passenger cars.

[0287] <Articles for manufacturing substrates with conductive patterns>

[0288] For example, for such Figure 2 An article as shown in D, comprising a substrate 1, a cured adhesive layer 2B disposed on the surface of the substrate 1, and a pattern 3B disposed on the surface of the cured adhesive layer 2B by means of a conductive composition containing conductive particles, can be regarded as a "semi-finished product" for manufacturing a substrate having a conductive pattern.

[0289] In other words, Figure 2The article shown in D is useful as an "article for manufacturing a substrate with a conductive pattern". By transferring the article to a third party and having the third party perform a pressing process, a substrate with a conductive pattern can be manufactured.

[0290] By the way, in Figure 2 In D, the easily peelable substrate 5 is peeled off, but it is also possible to use an article for manufacturing a substrate having a conductive pattern without peeling off the easily peelable substrate 5. From the viewpoint of suppressing the deterioration of the pattern 3B, an article for manufacturing a substrate having a conductive pattern may also have an easily peelable substrate 5.

[0291] about Figure 2 D has already been explained in detail, but to be on the safe side, examples are listed below. Figure 2 The following are possible features of articles manufactured using substrates with conductive patterns, as shown in D.

[0292] • Regarding the amount of resin component in pattern 3B, it 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, relative to 100 parts by mass of conductive particles.

[0293] • Pattern 3B is preferably composed of components that are substantially free of curable components, except for conductive particles.

[0294] • In the volume-based cumulative particle size distribution curve obtained by measuring the particle size of conductive particles in pattern 3B using laser diffraction scattering, the particle size D with a cumulative frequency of 50% is... 50 Preferably, the micrometer is 0.5~100μm, more preferably 0.6~50μm, even more preferably 0.7~30μm, and particularly preferably 0.7~20μm.

[0295] • The preferred substrate 1 is flexible.

[0296] • The preferred substrate 1 is selected from at least one of the group consisting of polyester, polyolefin, polycarbonate, polyimide and paper.

[0297] The thickness of the cured adhesive layer 2B is preferably 1 to 30 μm, more preferably 5 to 15 μm.

[0298] • A portion of the adhesive layer 2B is cured while immersed in the gaps between the conductive particles within the pattern 3B. This morphology is considered particularly helpful in improving the adhesion of the final conductive pattern.

[0299] The embodiments of the present invention have been described above, but these are merely examples, and various structures other than those described can be employed. Furthermore, the present invention is not limited to the above embodiments, and modifications and alterations made within the scope of achieving the objectives of the present invention are all included in the present invention.

[0300] Example

[0301] The embodiments of the present invention are described in detail based on examples and comparative examples. It should be noted that the present invention is not limited to these embodiments.

[0302] <Example I. Example using paper substrate>

[0303] (Manufacturing of conductive resin composition)

[0304] Manufacturing Example 1 (Resin-free)

[0305] Weigh D manufactured by Fukuda Metal Foil Powder Industry Co., Ltd. 50 77.0 parts by weight of copper powder with a particle size of 5 μm and 23.0 parts by weight of organic solvent were mixed using a scraper to obtain a compound. The compound was then stirred using a rotary mixer.

[0306] The conductive composition of Manufacturing Example 1 was obtained as described above. This composition is a paste at 23°C.

[0307] Manufacturing Example 2 (Contains resin components)

[0308] 15.0 parts by weight of commercially available phenoxy resin and 85.0 parts by weight of organic solvent were weighed into a glass bottle and placed in a hot air circulating oven. The bottle was heated at 120°C for 6 hours to completely dissolve the resin. A 15.0% by weight phenoxy resin solution was thus prepared.

[0309] Weigh D manufactured by Fukuda Metal Foil Powder Industry Co., Ltd. 50 75.3 parts by weight of copper powder with a particle size of 5 μm, 12.9 parts by weight of the above-mentioned 15% by weight phenoxy resin solution, and 11.9 parts by weight of organic solvent were mixed using a scraper. Then, the mixture was stirred using a rotary mixer.

[0310] The conductive composition of Formulation 2 was obtained as described above. This composition is a paste at 23°C.

[0311] (Example I-1: Manufacturing of a substrate with conductive patterns)

[0312] A substrate with conductive patterns was manufactured by performing the following processes.

[0313] (i) Formation of a provisional pattern onto the surface of an easily peelable substrate: equivalent to Figure 1 P1, Figure 1 P2

[0314] (ii) Formation of the adhesive layer onto the substrate: equivalent to Figure 1 A

[0315] (iii) Transfer printing process: equivalent to Figure 2 B

[0316] (iv) Adhesive layer curing process: equivalent to Figure 2 C

[0317] (v) Pressing before oxide film removal process: not shown

[0318] (vi) Stripping process: equivalent to Figure 2 D

[0319] (vii) Oxide film removal process and pressing process: equivalent to Figure 2 E and Figure 2 F

[0320] The details of each process are explained below.

[0321] (i) Formation of a provisional pattern onto the surface of an easily peelable substrate: equivalent to Figure 1 P1, Figure 1 P2

[0322] A provisional pattern was formed by screen printing the conductive composition of Manufacturing Example 1 (without resin) onto an easily peelable substrate. Specific conditions are as follows.

[0323] • Easy-to-peel substrate: PET film with silicone coating manufactured by Fujimori Kogyo Co., Ltd.

[0324] • Printing press: Desk Top 38SA screen printing press (Micro-tec).

[0325] • Screen printing plate: Use a 325 mesh screen with a wire diameter of 16μm and an emulsion thickness of 28μm.

[0326] Printing conditions: printing pressure 0.18MPa, squeegee speed 30mm / second, gap (distance between screen and substrate) 2.0mm, angle of attack 80°.

[0327] • Overall shape of the pattern: Set to Figure 3 The antenna pattern shown is shown in the figure. In this pattern, the width of the thin lines is 200 μm.

[0328] The screen-printed, easily peelable substrate is placed in a hot air circulating oven and heated at 100°C for 15 minutes. This causes the solvent to evaporate.

[0329] As described above, a provisional pattern with a height of 50 μm was formed on the surface of the easily peelable substrate.

[0330] (ii) Formation of the adhesive layer onto the substrate: equivalent to Figure 1 A

[0331] From the perspective of suppressing curling, double-coated paper, namely MirrorCoat Platinum (180μm thick, manufactured by Oji Paper Co., Ltd.), was selected as the substrate. Furthermore, considering penetration into the paper, the adhesive layer employs a two-layer structure. The specific steps for forming the adhesive layer are as follows.

[0332] First, a mixture was prepared by mixing epoxy resin YX7200B35 (Mitsubishi Chemical Corporation) and solvent tetrahydrofuran at a mass ratio of 1:1. This mixture was then applied to the substrate surface using a bar coater to a wet thickness of 30 μm. Next, the substrate was placed in a hot air circulating oven and heated at 100°C for 15 minutes. This caused the solvent to evaporate, forming the first adhesive layer.

[0333] Then, using a bar coater, the UV hard coating agent HX-RSC (Kyoeisha Chemical Co., Ltd., polyurethane acrylate material) was applied to the first adhesive layer with a wet thickness of 15 μm. Afterwards, the substrate was placed in a hot air circulating oven and heated at 80°C for 5 minutes. This caused the solvent to evaporate, forming the second adhesive layer (dry thickness 6 μm).

[0334] As described above, a substrate with an adhesive layer was obtained.

[0335] (iii) Transfer printing process: equivalent to Figure 2 B

[0336] The substrate with the adhesive layer obtained in (ii) above is overlapped on the provisional pattern obtained in (i) above, such that the provisional pattern is in contact with the adhesive layer. Then, pressure is applied using a 2 kg roller. As a result, the provisional pattern is transferred to the adhesive layer side, thereby becoming a transfer pattern.

[0337] (iv) Adhesive layer curing process: equivalent to Figure 2 C

[0338] Using a UV-LED irradiation machine (Matsuo Sangyo Co., Ltd.) emitting 365nm ultraviolet light, the adhesive layer with the transferred pattern after step (iii) was irradiated from the easily peelable substrate side with a cumulative UVA dose of 6000mJ / cm². 2 The ultraviolet light causes the adhesive layer to cure, thus obtaining a cured adhesive layer.

[0339] (v) Pressing before oxide film removal process

[0340] Using a load-adjustable roller press SA-602 (Tester Industrial Co., Ltd.) with two opposing rollers, the laminate containing the substrate, cured adhesive layer, transfer pattern and easy-to-peel substrate after (iv) above was rolled under the following conditions.

[0341] Roller temperature: 110℃, pressure: 20MPa, conveying speed: 0.1m / min, gap: 90-100μm

[0342] (Note 1: Regarding the roller temperature, the roller press is equipped with a non-contact temperature sensor, but a contact thermometer was used for measurement to obtain more accurate temperature readings.)

[0343] (Note 2: The pressure was obtained through the following calculations.)

[0344] Based on a roll width of 165mm, a roll-to-roll contact width of 3mm, and an applied pressure area of ​​495mm², 2 The pressure was set to 10 kN. Then, due to the pressure at 495 mm... 2 A force of 10kN was applied to the area. The result was calculated as 10kN ÷ 495mm. 2 Therefore, the pressure was calculated to be 20 MPa.

[0345] (vi) Stripping process: equivalent to Figure 2 D

[0346] After (v) above was completed, the easily peelable substrate was peeled off by hand.

[0347] (vii) Oxide film removal process and pressing process: equivalent to Figure 2 E and Figure 2 F

[0348] An oxide film removal solution (formic acid aqueous solution) is sprayed onto the pattern (transfer pattern) as described above (vi) using a sprayer. The spray volume is approximately 20 μL relative to an area of ​​approximately 30 mm × 20 mm in size on the substrate. Then, a film-like component (the same easily peelable substrate used to form the provisional pattern, manufactured by Fujimori Kogyo Co., Ltd.) is overlapped. In this state, a load-adjustable roller press SA-602 (Tester Sangyo Co., Ltd.) with two opposing rollers is used for roller pressing. The processing conditions are set as follows.

[0349] Roller temperature: 110℃, pressure: 40MPa, conveying speed: 0.1m / min, gap: 40-50μm

[0350] (Note: The calculation method for roller temperature and pressure is the same as Notes 1 and 2 for pressing before the oxide film removal process (v).)

[0351] As described above, the pattern (transfer pattern) is pressed while allowing the oxide film removal solution to penetrate into the gaps between the conductive particles in the pattern (transfer pattern). This results in a conductive pattern.

[0352] Through the above series of processes, a substrate with conductive patterns is obtained, in which a conductive antenna pattern is formed on a paper substrate through a cured adhesive layer.

[0353] (Example I-2: Manufacturing of a substrate with conductive patterns)

[0354] Except for using Manufacturing Example 2 (containing resin components) instead of Manufacturing Example 1 (containing no resin components) as the conductive component, the same procedures as in Example I-1 were performed. Thus, a substrate with a conductive pattern was manufactured.

[0355] (Example I-3: Manufacturing of a substrate with conductive patterns)

[0356] Except for using Manufacturing Example 2 (with resin component) instead of Manufacturing Example 1 (without resin component) as the conductive component and omitting the pressing before the (v) oxide film removal process, the same processes as in Example I-1 were performed. A substrate with a conductive pattern was thus manufactured.

[0357] (Comparative Example I-1: Manufacturing of a substrate with conductive patterns)

[0358] Except for skipping the formation of the adhesive layer onto the substrate as described in (ii) above and directly performing the (iii) transfer process on the substrate, the other processes are the same as in Example I-1.

[0359] However, in this case, the adhesion of the conductive pattern was extremely low, and only a small force was applied to cause the conductive pattern to peel off from the substrate.

[0360] (Evaluation: Fit)

[0361] The conductive patterned substrates of Examples I-1 to I-3 were bent by hand and then restored to their original flat shape, repeated 5 times. Afterwards, the presence or absence of conductive pattern peeling was confirmed by visual inspection and magnification. Cases where no conductive pattern peeling was observed were rated as good, and cases where conductive pattern peeling was observed were rated as poor.

[0362] (Evaluation: Resistance value)

[0363] The measurements obtained in Examples I-1 to I-3, having Figure 3 The resistance values ​​between points 1 and 2 and between points 3 and 4 in the pattern shown.

[0364] (Evaluation: Pattern forming accuracy)

[0365] By magnifying and observing the conductive patterns obtained in Examples I-1 to I-3, it was evaluated whether the provisional patterns formed on the easily peelable substrate were transferred to the substrate almost exactly. Specifically, it was evaluated whether the 200 μm linewidth portion of the provisional pattern was transferred to the substrate and became a conductive pattern within a linewidth variation range of ±20 μm. Cases with linewidth variations within ±20 μm were evaluated as good, and cases with linewidth variations exceeding ±20 μm were evaluated as bad.

[0366] The above information is summarized in the table below.

[0367] In the table below, no further evaluation was conducted because the fit evaluation results of Comparative Example I-1 were poor.

[0368]

[0369] As shown in the table above, the method for manufacturing a substrate with conductive patterns according to this embodiment can produce a substrate with conductive patterns that has good adhesion evaluation.

[0370] Furthermore, it was confirmed that the resistance of the conductive patterns in the obtained substrate with conductive patterns is sufficiently low, and that they possess good conductivity. Additionally, for practically used aluminum foil antennas (whose shape and overall size are similar to...), Figure 3 (Similar to the antenna), the resistance value measured in the same way as described above (evaluation: resistance value) is approximately 6.2Ω. In the evaluation of the resistance values ​​of Examples I-1 to I-3, despite the narrower wiring width, resistance values ​​of 6.2Ω or less were shown. Therefore, it can be said that the conductivity of the conductive patterns obtained in Examples I-1 to I-3 is no less than, and may even exceed, that of the prior art.

[0371] Furthermore, the conductive pattern is formed with good precision.

[0372] (Additional evaluation: Antenna performance)

[0373] An IC chip (insertion) with an antenna was fabricated on a substrate with a conductive pattern obtained in Example 1. The antenna performance was then evaluated using the insert.

[0374] The maximum communication distance was measured using the obtained insert.

[0375] The measurement results show that the maximum communication distance is 6.7m (990MHz).

[0376] Considering the practical aluminum foil antennas measured for reference (shape and overall size compared to...) Figure 3The maximum communication distance (similar to an antenna) is 3.0m (960MHz). It can be said that the substrate with conductive patterns obtained in this embodiment can be preferably used in the manufacture of antenna parts, for example, in RF tags.

[0377] <Example II. Example using polyethylene terephthalate (PET) substrate>

[0378] (Example II-1: Manufacturing of a substrate with conductive patterns)

[0379] A substrate with conductive patterns was manufactured by performing the following processes.

[0380] (i) Formation of a provisional pattern onto the surface of an easily peelable substrate: equivalent to Figure 1 P1, Figure 1 P2

[0381] (ii) Formation of the adhesive layer onto the substrate: equivalent to Figure 1 A

[0382] (iii) Transfer printing process: equivalent to Figure 2 B

[0383] (iv) Adhesive layer curing process: equivalent to Figure 2 C

[0384] (v) Pressing before oxide film removal process: not shown

[0385] (vi) Stripping process: equivalent to Figure 2 D

[0386] (vii) Oxide film removal process and pressing process: equivalent to Figure 2 E and Figure 2 F

[0387] The details of each process are explained below.

[0388] (i) Formation of a provisional pattern onto the surface of an easily peelable substrate: equivalent to Figure 1 P1, Figure 1 P2

[0389] Except for using the conductive composition of Manufacturing Example 2 (with resin component) instead of Manufacturing Example 1 (without resin component), the provisional pattern is formed on the surface of the easily peelable substrate in the same manner as in Example I-1 (i).

[0390] (ii) Formation of the adhesive layer onto the substrate: equivalent to Figure 1 A

[0391] As the substrate, a PET film manufactured by Toray Industries, Inc., namely Lumirror U34 (75 μm thick), was selected. Unlike the paper substrate of Example I, the PET film does not have a substantially permeable component constituting the adhesive layer; therefore, the adhesive layer is a single layer. Specifically, a UV hard coating agent HX-RSC (Kyoeisha Chemical Co., Ltd., a polyurethane acrylate material) was applied to the surface of the PET film with a wet thickness of 30 μm using a rod coater. The substrate was then placed in a hot air circulating atmospheric oven and heated at 80°C for 15 minutes. This caused the solvent to evaporate, thereby forming an adhesive layer (dry thickness 4 μm).

[0392] As described above, a substrate with an adhesive layer was obtained.

[0393] (iii) Transfer printing process: equivalent to Figure 2 B

[0394] Similar to (iii) of Example I-1, a provisional pattern is transferred to the adhesive layer side.

[0395] (iv) Adhesive layer curing process: equivalent to Figure 2 C

[0396] Similar to (iv) of Example I-1, the adhesive layer is cured to obtain a cured adhesive layer.

[0397] (v) Pressing before oxide film removal process

[0398] Rolling is performed in the same manner as in Example I-1 (v).

[0399] (vi) Stripping process: equivalent to Figure 2 D

[0400] Similar to (vi) of Example I-1, the easily peelable substrate was peeled off.

[0401] (vii) Oxide film removal process and pressing process: equivalent to Figure 2 E and Figure 2 F

[0402] Similar to (vii) of Example I-1, an oxide film removal process and a pressing process were performed.

[0403] (Comparative Example II-1: Manufacturing of a substrate with conductive patterns)

[0404] Except for skipping the formation of the adhesive layer onto the substrate as described in (ii) above and performing the (iii) transfer process directly on the substrate, the same process as in Example II-1 is performed.

[0405] However, in this case, the adhesion of the conductive pattern was extremely low, and only a small force was applied to cause the conductive pattern to peel off from the substrate.

[0406] (Evaluation: Fit)

[0407] Similar to the adhesion evaluation in Example I, the presence or absence of delamination of the conductive pattern was confirmed by visual inspection and magnification.

[0408] (Evaluation: Resistance value)

[0409] Similar to the resistance value evaluation in Example I, the resistance value was measured.

[0410] (Evaluation: Pattern forming accuracy)

[0411] Similar to the pattern forming accuracy evaluation in Example I, the pattern forming accuracy was evaluated.

[0412] The above information is summarized in the table below.

[0413] In the table below, no further evaluation was conducted because the fit evaluation results of Comparative Example II-1 were poor.

[0414]

[0415] As shown in the table above, even when using PET film as the substrate, the method for manufacturing a substrate with conductive patterns according to this embodiment can produce a substrate with good adhesion evaluation.

[0416] Furthermore, it was confirmed that the resistance value of the conductive pattern in the obtained substrate with the conductive pattern is sufficiently small, exhibiting good conductivity. Additionally, while the values ​​of 12.5Ω and 12.8Ω measured in Example II-1 are larger than the resistance values ​​of the conductive patterns obtained in Examples I-1 to I-3, they are sufficiently small, for example, considering their application in RF tags.

[0417] Furthermore, the conductive pattern is formed with good precision.

[0418] <Reference: Electron microscopy of patterned cross-sections>

[0419] The substrate with conductive patterns obtained in Example I-1 was cut, and the cross-section of the conductive pattern portion was photographed using an electron microscope. The photographed image is shown below. Figure 4 As can be seen from the figure, the adhesive layer cures when the components constituting the adhesive layer (such as resin) penetrate into the gaps between the conductive particles to a depth of 4.0 μm.

[0420] Furthermore, the substrate with the conductive pattern obtained in Example II-1 was cut, and the cross-section of the conductive pattern portion was photographed using an electron microscope. The photographed image is shown below. Figure 5As can be seen from the figure, the adhesive layer cures when the components constituting the adhesive layer (such as resin) penetrate into the gaps between the conductive particles to a depth of 15.7 μm.

[0421] The penetration of conductive particles into the gaps in the isotropic conductive patterns of resin shown in these figures is believed to contribute to the good adhesion of the conductive patterns.

[0422] In addition, such as Figure 4 and Figure 5 As shown, even when a portion of the conductive pattern was impregnated with resin or the like, conductive patterns with good conductivity were obtained in Examples I-1 and II-1. It can be considered that even if the conductive particles in the portion of the conductive pattern near the cured adhesive layer are not sintered, as long as the conductive particles near the surface of the conductive pattern (for example, from the surface of the conductive pattern to a depth of about 5 μm, or to a depth of about 10 μm) are sufficiently sintered, the resistance value of the conductive pattern is sufficiently small.

[0423] This application claims priority based on Japanese Patent Application No. 2024-040844, filed on March 15, 2024, the entire contents of which are incorporated herein by reference.

[0424] Explanation of reference numerals in the attached figures

[0425] 1...substrate; 2...adhesive layer; 2B...cured adhesive layer; 3...pattern; 3B...provisional pattern; 3C...conductive pattern; 5...easily peelable substrate; 6...component (preferably a film); 7...liquid containing component X of an oxide film capable of removing conductive particles from the surface; 10A...roller; 10B...roller.

Claims

1. A method for manufacturing a substrate having a conductive pattern, characterized in that, include: In the transfer process, a provisional pattern provided on the surface of an easy-to-peel substrate using a conductive composition containing conductive particles is brought into contact with an adhesive layer provided on the surface of a substrate different from the easy-to-peel substrate, thereby obtaining a transfer pattern in which the provisional pattern is transferred to the surface of the adhesive layer. as well as In the pressing process, pressure is applied to the transfer pattern to obtain a conductive pattern.

2. The method for manufacturing a substrate with a conductive pattern according to claim 1, characterized in that, The adhesive layer has at least one of thermosetting or photocurable properties. Between the transfer process and the pressing process, there is an adhesive layer curing process that allows the adhesive layer to be cured.

3. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, The conductive particles in the provisional pattern are not substantially sintered.

4. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, The provisional pattern is not actually solidified.

5. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, After the transfer process and before or simultaneously with the pressing process, there is an oxide film removal process that brings the component X of the oxide film on the surface capable of removing the conductive particles into contact with the transfer pattern.

6. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, In the pressing process, the transfer pattern is heated while pressure is applied to the transfer pattern.

7. The method for manufacturing a substrate having a conductive pattern according to claim 6, characterized in that, In the pressing process, the transfer pattern is pressed with a pressure of 1 to 5000 MPa and heated with a temperature of 50 to 400°C.

8. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, The conductive component is a paste at room temperature.

9. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, The amount of resin component in the conductive composition is 15 parts by mass or less relative to 100 parts by mass of the conductive particles.

10. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, The conductive component, as a component other than the conductive particles, substantially does not contain any curing components.

11. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, In the volume-based cumulative particle size distribution curve obtained by measuring the particle size of the conductive particles using laser diffraction scattering, the particle size D with a cumulative frequency of 50% is... 50 The range is 0.5~100μm.

12. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, In the pressing process, after the exposed surface of the transfer pattern is covered with a component, pressure is applied to the transfer pattern at least once.

13. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, The easily peelable substrate is a resin film or release paper.

14. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, Prior to the pressing process, a peeling process is included to peel off the easily peelable substrate.

15. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, The substrate is flexible.

16. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, The substrate is selected from at least one of polyester, polyolefin and polycarbonate.

17. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, The substrate is polyimide.

18. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, The substrate is paper.

19. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, The thickness of the adhesive layer is 1~30μm.

20. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, The height of the provisional pattern is 0.5~100μm.

21. The method for manufacturing a substrate having a conductive pattern according to claim 1 or 2, characterized in that, In the transfer process, a pressing action is performed to improve the adhesion between the provisional pattern and the adhesive layer.

22. A method for manufacturing an electronic device, characterized in that, Electronic devices are manufactured using a substrate with a conductive pattern obtained by the manufacturing method of a substrate with a conductive pattern as described in claim 1 or 2.

23. The method for manufacturing an electronic device according to claim 22, characterized in that, The electronic device is an RF tag.

24. A method for manufacturing an electromagnetic wave shielding film, characterized in that, An electromagnetic wave shielding film is manufactured using a substrate with a conductive pattern obtained by the manufacturing method of a substrate with a conductive pattern as described in claim 1 or 2.

25. A method for manufacturing a planar heating element, characterized in that, A planar heating element is manufactured using a substrate with a conductive pattern obtained by the manufacturing method of the substrate with a conductive pattern as described in claim 1 or 2.

26. An article for manufacturing a substrate having a conductive pattern, characterized in that, have: Substrate; A cured adhesive layer, which is a cured material disposed on the surface of the substrate and having at least one property of photocurability or thermosetting; and The pattern is formed on the surface of the cured adhesive layer by means of a conductive composition containing conductive particles.

27. The article according to claim 26, characterized in that, The amount of resin component in the pattern is: less than 15 parts by mass relative to 100 parts by mass of the conductive particles.

28. The article according to claim 26 or 27, characterized in that, The pattern, apart from the conductive particles, substantially contains no curable components.

29. The article according to claim 26 or 27, characterized in that, In the volume-based cumulative particle size distribution curve obtained by measuring the particle size of the conductive particles using laser diffraction scattering, the particle size D with a cumulative frequency of 50% is... 50 The range is 0.5~100μm.

30. The article according to claim 26 or 27, characterized in that, The substrate is flexible.

31. The article according to claim 26 or 27, characterized in that, The substrate is selected from at least one of polyester, polyolefin and polycarbonate.

32. The article according to claim 26 or 27, characterized in that, The substrate is polyimide.

33. The article according to claim 26 or 27, characterized in that, The substrate is paper.

34. The article according to claim 26 or 27, characterized in that, The thickness of the cured adhesive layer is 1~30μm.

35. The article according to claim 26 or 27, characterized in that, A portion of the cured adhesive layer is cured while immersed in the gaps between the conductive particles within the pattern.

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