Method for manufacturing conductive film laminate

Abstract

To provide a method for manufacturing a conductive film laminate having stable film quality and a conductive film laminate.SOLUTION: There is provided a method for manufacturing a conductive film laminate 1 comprising a base material to be laminated 10, an adhesive layer 20 formed on the surface of the base material to be laminated 10 and a carbon conductive film 30 formed on the surface of the adhesive layer 20, which comprises: a first laminate preparation step of preparing a first laminate 110 comprising a substrate 40 for forming a carbon conductive film 30 on the surface, a carbon conductive film 30 formed on the surface of the substrate 40 and an adhesive layer 20 formed on the surface of the carbon conductive film 30; a heat pressing step of bringing the adhesive layer 20 of the first laminate 110 and the base material to be laminated 10 into contact with each other, followed by heating and pressing to prepare a second laminate 120; and an etching step of etching a substrate 40 for forming the second laminate 120 to prepare a conductive film laminate 1.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a conductive film laminate and a conductive film laminate. [Background technology]

[0002] Single-walled carbon nanotubes (SWCNTs) have excellent mechanical, electrical, and thermal properties, as well as high flexibility. For this reason, SWCNT films containing SWCNTs are expected to be used as next-generation flexible conductive materials.

[0003] Patent Document 1 discloses a method for producing a graphene sheet in which a laminate of a carbonization catalyst, a graphene sheet, a binder layer, and a substrate is immersed in an acid solution A as an etchant to remove the carbonization catalyst. Patent Document 1 also discloses that the binder layer is formed by coating with a highly insulating siloxane compound, acrylic compound, or the like. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-298683 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the binder layer formed by the coating method of Patent Document 1 usually contains a solvent component such as alcohol or ester. Therefore, in the invention disclosed in Patent Document 1, the solvent component or the like volatilizes during the binder layer curing step, which tends to reduce the adhesion between the binder layer and the graphene sheet and cause bubbles to form.

[0006] The graphene sheet laminate of Ni (carbonization catalyst film) / graphene sheet / binder layer / substrate shown in Fig. 3 of Patent Document 1 is produced by a known method. Therefore, it is considered that the graphene sheet laminate shown in Fig. 3 of Patent Document 1 does not solve the problems of reduced adhesion between the binder layer and the graphene sheets and generation of bubbles.

[0007] Thus, conventionally, a conductive film laminate including a carbon conductive film with stable film quality and a method for manufacturing the same have not been known.

[0008] The present invention has been made in view of the problems inherent in the prior art, and an object of the present invention is to provide a method for manufacturing a conductive film laminate having stable film quality, and a conductive film laminate. [Means for solving the problem]

[0009] A method for manufacturing a conductive film laminate according to a first aspect of the present invention is a method for manufacturing a conductive film laminate comprising a substrate to be laminated, an adhesive layer formed on the surface of the substrate to be laminated, and a carbon conductive film formed on the surface of the adhesive layer, and comprises: a first laminate manufacturing step of manufacturing a first laminate comprising a formation substrate for forming the carbon conductive film on its surface, the carbon conductive film formed on the surface of the formation substrate, and an adhesive layer formed on the surface of the carbon conductive film; a thermocompression bonding step of bringing the adhesive layer of the first laminate into contact with the substrate to be laminated, and then performing thermocompression bonding to manufacture a second laminate; and an etching step of etching the formation substrate of the second laminate to manufacture the conductive film laminate.

[0010] A conductive film laminate according to a second aspect of the present invention comprises a substrate to be laminated, an adhesive layer formed on the surface of the substrate to be laminated, and a carbon conductive film formed on the surface of the adhesive layer, wherein the carbon conductive film is an SWCNT film that is a network structure of single-walled carbon nanotubes, and the adhesive layer contains a cured adhesive and metal ions. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a method for manufacturing a conductive film laminate with stable film quality, and a conductive film laminate. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view showing an example of a conductive film stack according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing an example of a first laminate according to the present embodiment. [Figure 3] FIG. 1 is a cross-sectional view showing an example of a CNT coating composite according to an embodiment of the present invention. [Figure 4] FIG. 1 is a cross-sectional view showing an example of a carbon conductive membrane composite according to an embodiment of the present invention. [Figure 5] 1 is an SEM photograph of the surface of an example of an SWCNT film (carbon conductive film) according to this embodiment. [Figure 6] FIG. 2 is a cross-sectional view showing an example of a composite body before thermocompression bonding according to the present embodiment. [Figure 7] FIG. 3 is a cross-sectional view showing an example of a second laminate according to the present embodiment. [Figure 8] 4 is an optical photograph showing an example of a second laminate according to the present embodiment. [Figure 9] 10A to 10C are cross-sectional views illustrating an example of an etching step of the second stack according to the embodiment. [Figure 10] 1 is an SEM photograph of the surface of an example of an SWCNT film (carbon conductive film) according to this embodiment. [Figure 11] 1 is an optical photograph showing an example of a conductive film stack according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] The conductive film laminate according to this embodiment will be described in detail below with reference to the drawings. Note that the dimensional proportions in the drawings are exaggerated for the sake of explanation and may differ from the actual proportions.

[0014] [Conductive film laminate] Fig. 1 is a cross-sectional view showing an example of a conductive film laminate according to this embodiment. The conductive film laminate 1A(1) shown in Fig. 1 includes a laminated substrate 10, an adhesive layer 20A(20) formed on the surface of the laminated substrate 10, and a carbon conductive film 30A(30) formed on the surface of the adhesive layer 20A.

[0015] The conductive film laminate 1A is formed by firmly bonding the laminated substrate 10, adhesive layer 20A, and carbon conductive film 30A together through thermocompression bonding in a thermocompression bonding step during manufacturing. Furthermore, the conductive film laminate 1A contains a cured adhesive and metal ions 60 in the adhesive layer 20A due to contact with an etchant in an etching step performed after the thermocompression bonding step during manufacturing.

[0016] (Laminated base material) The lamination substrate 10 is a resin substrate on which the carbon conductive film 30A is laminated via an adhesive layer 20A. The lamination substrate 10 is made of, for example, polyethylene terephthalate (PET, glass transition temperature T g :69℃), polybutylene terephthalate (PET, glass transition temperature T g : 50℃), polyethylene (glass transition temperature T g : -125℃), polypropylene (glass transition temperature T g :0℃), polyvinyl chloride (glass transition temperature T g : 87℃), polystyrene (glass transition temperature T g :100℃), acrylonitrile-butadiene-styrene resin (ABS, glass transition temperature T g : 80 to 125°C), polymethyl methacrylate (glass transition temperature T g : 90℃), Polyamide 6 (glass transition temperature T g : 50℃), Polyamide 66 (glass transition temperature T g : 50℃), polyacetal (glass transition temperature T g :-50℃), polycarbonate (glass transition temperature T g :150℃), polyphenylene sulfide (glass transition temperature T g : 126℃), polyurethane (glass transition temperature T g : -20℃), polyethersulfone (glass transition temperature Tg : 230℃), polyphenylene oxide (glass transition temperature T g : 104 to 120°C), polyamide-imide (glass transition temperature T g : 275℃), polylactic acid (glass transition temperature T g : 57℃), polytetrafluoroethylene (glass transition temperature T g :126℃), ethylene-vinyl acetate copolymer (EVA, glass transition temperature T g : -42℃), polyacrylonitrile (glass transition temperature T g : 104℃), polyvinylidene fluoride (glass transition temperature T g 35°C) is used. Of these, PET resin has a relatively low glass transition temperature of 69°C and a high heat resistance temperature of 220°C, so the material is highly stable during thermocompression bonding and is also highly flexible. For this reason, it is highly preferable that the laminated substrate 10 is made of PET resin, as it can be easily and firmly bonded to the adhesive layer 20A.

[0017] In the conductive film laminate 1A produced through the thermocompression bonding step, the interface between the lamination-receiving substrate 10 and the adhesive layer 20A is usually firmly bonded, as will be described later.

[0018] (Adhesive layer) The adhesive layer 20A is a layer that is disposed between the laminated substrate 10 and the carbon conductive film 30A, and then firmly bonds the laminated substrate 10 and the carbon conductive film 30A together by thermocompression bonding. Specifically, the adhesive layer 20A contains a cured product of an adhesive that is formed by the adhesive being cured by thermocompression bonding. Furthermore, the conductive film laminate 1A is usually prone to contain metal ions 60 in the adhesive layer 20A due to contact with an etchant 50 in the etching step during manufacturing. That is, the adhesive layer 20A may contain both the cured product of the adhesive and the metal ions 60.

[0019] The metal ions 60 used may be metal ions contained in the etchant 50 or metal ions derived from the formation substrate 40 that are generated when the formation substrate 40 comes into contact with the etchant 50 and is etched. When the adhesive layer 20A contains metal ions, a doping effect is generated that improves the movement of electrons between the carbon conductive film 30A and the laminated substrate 10 via the adhesive layer 20A, thereby improving the conductivity of the conductive film laminate 1A as a whole, which is preferable.

[0020] For example, when the etchant 50 is an iron ion-containing liquid such as an aqueous solution of iron nitrate or iron chloride, the Fe 3+ is reduced to Fe 2+ may be contained as metal ions 60 in the adhesive layer 20A.

[0021] In addition, when the forming substrate 40 is a Cu plate, Cu generated when the Cu plate 40 comes into contact with the etchant 50 and is etched. 2+ may be contained in the adhesive layer 20A as metal ions 60. Therefore, the metal ions contained in the adhesive layer 20A are Cu 2+ and Fe 2+ It may include:

[0022] It is preferable that the adhesive layer 20A is made using an etchant 50 with a metal ion concentration of 0.52 mol / L or more, because the content of metal ions contained in the adhesive layer 20A is high, which tends to increase the conductive effect of the SWCNT film (carbon conductive film) 30A of the conductive film laminate 1A.

[0023] Examples of adhesives that can be used include acrylic adhesives, modified acrylic adhesives, silicone adhesives, urethane adhesives, and rubber adhesives. Of these, acrylic adhesives and modified acrylic adhesives are preferred because they have high transparency and heat resistance and can be used in TOM molding, etc. Here, modified acrylic adhesives refer to adhesives that have been given functional groups that easily adsorb moisture to increase the polarity of the resin in order to impart hydrophilicity.

[0024] Generally, increasing the polarity of a molecule increases the electron separation between the molecules, strengthening the force of attraction between the molecules (intermolecular force). Therefore, when the polarity of a resin increases, the highly polar molecules of the resin tend to adsorb water more easily, making the resin hydrophilic. On the other hand, when the polarity of a resin decreases, the highly polar molecules of the resin tend to adsorb water less easily, making the resin hydrophobic.

[0025] The modified acrylic adhesive may be, for example, an acrylic adhesive modified by adding a hydroxyl group (-OH), a carboxyl group (-COOH), an amino group (-NH2), a carbonyl group (-CO), etc. to the terminal of the molecule. More specifically, the modified acrylic adhesive may be the adhesive constituting the adhesive layer of Modified Acrylic Adhesive G25 manufactured by Nichiei Shinka Co., Ltd.

[0026] Acrylic adhesives and modified acrylic adhesives are preferred because they have high heat resistance and transparency, making it possible to fabricate conductive film laminates 1A with complex three-dimensional shapes using TOM molding.Modified acrylic adhesives are also more preferred because they tend to incorporate metal ions into the adhesive layer 20A.

[0027] The adhesive layer 20A may contain a cured product of an acrylic adhesive. Acrylic adhesives are preferred because they have a relatively low glass transition temperature, which allows the adhesive layer 20A to easily and firmly adhere to the laminated substrate 10, the carbon conductive film 30A, and the like. In addition, a cured product of an acrylic adhesive has high transparency, heat resistance, and elongation conformity, and is therefore capable of absorbing outgassing and trace amounts of moisture generated from the laminated substrate 10 during manufacturing. For this reason, it is preferred that the adhesive layer 20A contain a cured product of an acrylic adhesive, as this can prevent the adhesive layer 20A from absorbing gases or water, thereby preventing bubbles or lifting.

[0028] Examples of acrylic adhesives that can be used include ethyl acrylate adhesives, methyl acrylate adhesives, butyl acrylate adhesives, and methyl methacrylate adhesives. Examples of modified acrylic adhesives that can be used include adhesives that have been modified by adding a functional group that easily adsorbs moisture to the monomer of the adhesive. That is, in this embodiment, the cured product of the acrylic adhesive can be a cured product of a water-absorbent acrylic adhesive.

[0029] Acrylic adhesives and modified acrylic adhesives typically have smaller molecular weights than general PMMA polymers. Therefore, the glass transition temperatures of acrylic adhesives and modified acrylic adhesives are typically lower than the glass transition temperature of general PMMA polymers, which is 90°C, for example, 70 to 80°C. It is preferable that the cured adhesive be made of an acrylic adhesive or modified acrylic adhesive, because the low glass transition temperature facilitates strong adhesion to the laminated substrate 10, the carbon conductive film 30A, etc.

[0030] The adhesive layer 20A is interposed between the laminated substrate 10 and the carbon conductive film 30A, and typically has a thickness that is reduced after thermocompression bonding compared to before thermocompression bonding. That is, in the thermocompression bonding step of the manufacturing method of the conductive film laminate 1A, the adhesive disposed between the laminated substrate 10 and the carbon conductive film 30A is reduced in thickness by thermocompression bonding to become the adhesive layer 20A.

[0031] During thermocompression bonding, the materials constituting each layer are likely to be strongly bonded together at the interface between the adhesive layer 20A and the substrate 10 and at the interface between the adhesive layer 20A and the carbon conductive film 30A. For example, during thermocompression bonding, the resin molecules constituting the substrate 10 become entangled with the adhesive molecules constituting the adhesive layer 20A due to micro-Brownian motion, etc., which tends to strongly bond adjacent layers. In this way, the conductive film laminate 1A produced through the thermocompression bonding process is usually strongly bonded at the interface between the adhesive layer 20A and the substrate 10 and at the interface between the adhesive layer 20A and the carbon conductive film 30A.

[0032] Furthermore, when the adhesive is an acrylic adhesive or a modified acrylic adhesive, the adhesive is typically heated and compressed at a temperature higher than its glass transition temperature during thermocompression bonding. Therefore, when the adhesive is an acrylic adhesive or a modified acrylic adhesive, the solvent component contained in the resin constituting the adhesive is released during thermocompression bonding, thereby forming adhesive layer 20A into a strong film.

[0033] The thickness of the adhesive layer 20A is, for example, 5 to 100 μm, preferably 10 to 50 μm, and more preferably 20 to 30 μm. When the thickness of the adhesive layer 20A is within the above range, transparency and metal ion adsorption are favorably maintained, which is preferable.

[0034] (Carbon conductive film) The carbon conductive film 30A (30) is a conductive film containing a carbon material. Fig. 5 is an SEM photograph of the surface of an example of the carbon conductive film according to this embodiment. The carbon conductive film 30A shown in Fig. 5 is an SWCNT film 30A, which is a network structure of single-walled carbon nanotubes 35. The SWCNT film 30A usually has a large number of voids.

[0035] In the conductive film laminate 1A, the carbon conductive film 30 is an SWCNT film 30A, but as a modification of the conductive film laminate 1A, a carbon conductive film 30 other than an SWCNT film may be used. For example, as a modification of the conductive film laminate 1A, a carbon conductive film 30 including a graphene film may be used.

[0036] The single-walled carbon nanotubes 35 contained in the SWCNT film 30A have a central diameter of, for example, 0.5 to 5 nm, preferably 1 to 3 nm, and a length of, for example, 1 to several tens of μm.

[0037] The thickness of the SWCNT film 30A is, for example, 50 to 500 nm, and preferably 100 to 200 nm.

[0038] It is preferable that the carbon conductive film 30 is an SWCNT film 30A, because the SWCNT film 30A and the adhesive layer 20A are easily strongly bonded together by thermocompression bonding in a thermocompression bonding step during the production of the conductive film laminate 1A. The strong bond between the SWCNT film 30A and the adhesive layer 20A is achieved, for example, by entanglement of the single-walled carbon nanotubes 35 constituting the SWCNT film 30A with the molecules of the adhesive constituting the adhesive layer 20A during the thermocompression bonding step.

[0039] In the conductive film laminate 1A produced through the thermocompression bonding step, as described above, the interface between the carbon conductive film 30A and the adhesive layer 20A is usually firmly bonded.

[0040] (effect) According to the conductive film laminate 1A, a conductive film laminate with stable film quality can be provided.

[0041] Furthermore, when the adhesive layer 20A of the conductive film laminate 1A contains metal ions 60, the conductive effect of the SWCNT film (carbon conductive film) 30A of the conductive film laminate 1A can be further improved.

[0042] The conductive film laminate 1A is manufactured, for example, by the conductive film laminate manufacturing method described below.

[0043] [Method of manufacturing conductive film laminate] The method for manufacturing a conductive film laminate is a method for manufacturing a conductive film laminate 1A(1) comprising a laminated substrate 10, an adhesive layer 20A(20) formed on the surface of the laminated substrate 10, and a carbon conductive film 30A(30) formed on the surface of the adhesive layer 20A. The method for manufacturing a conductive film laminate comprises a first laminate fabrication step, a thermocompression bonding step, and an etching step.

[0044] (First laminate manufacturing process) The first laminate production process is a process of producing a first laminate 110 comprising a formation substrate 40 for forming a carbon conductive film 30 on its surface, the carbon conductive film 30 formed on the surface of the formation substrate 40, and an adhesive layer 20 formed on the surface of the carbon conductive film 30.

[0045] Fig. 2 is a cross-sectional view showing an example of a first laminate according to this embodiment. As shown in Fig. 2, the first laminate 110 includes a formation substrate 40, an SWCNT film 30A (30), and an adhesive layer 20B (20). The SWCNT film 30A is the same as that described in the above [Conductive Film Laminate], and therefore a description thereof will be omitted. The adhesive layer 20B is the same as the adhesive layer 20A described in the above [Conductive Film Laminate], except that it does not contain the metal ions normally contained in the adhesive layer 20A.

[0046] Here, the reason why the adhesive layer 20B does not usually contain metal ions is that the adhesive layer 20B does not come into contact with the etchant 50 in the etching step described below. That is, the adhesive layer 20A described above in [Conductive film laminate] is the adhesive layer 20 after coming into contact with the etchant 50 in the etching step, and therefore usually contains metal ions. In contrast, the adhesive layer 20B is the adhesive layer 20 that does not come into contact with the etchant 50 in the etching step, and therefore usually does not contain metal ions.

[0047] <Formation substrate> The formation substrate 40 is a metal substrate on the surface of which the SWCNT film 30A (30) is formed. The material of the formation substrate 40 is, for example, a metal containing Cu, Ni, Ge, Co, or Ru. If the material of the formation substrate 40 is made of these metals, the formation substrate 40 is preferably heat-resistant and easily etched.

[0048] Among these, when the formation substrate 40 is a Cu plate made of a Cu-containing metal, it is preferable because the carbon content is low and therefore alloy formation with the carbon film at the interface is unlikely, etching is easy, and it is inexpensive.

[0049] FIG. 3 is a cross-sectional view showing an example of a CNT coated film composite according to this embodiment. FIG. 4 is a cross-sectional view showing an example of a carbon conductive film composite according to this embodiment. The first laminate 110 shown in FIG. 2 is produced by forming an adhesive layer 20B on the surface of the SWCNT film 30A (30) of the carbon conductive film composite 105 shown in FIG. 4. The carbon conductive film composite 105 shown in FIG. 4 is produced from the CNT coated film composite 100 shown in FIG. 3. In this way, the first laminate 110 shown in FIG. 2 is produced by forming an adhesive layer 20B on the surface of the SWCNT film 30A (30) of the carbon conductive film composite 105 shown in FIG. 4, which was produced using the CNT coated film composite 100 shown in FIG. 3.

[0050] The CNT coating composite 100 shown in FIG. 3 is composed of a forming substrate 40 and a CNT ink 34 or a CNT coating 39 made of the CNT ink 34 with increased viscosity applied to the surface of the forming substrate 40.

[0051] 4 comprises a forming substrate 40 and an SWCNT film 30A (30) formed on the surface of the forming substrate 40. The SWCNT film 30A of the carbon conductive film composite 105 is obtained by removing the dispersant and dispersion solvent from the CNT coating film 39 of the CNT coating film composite 100 shown in FIG.

[0052] When the CNT coated film composite 100 shown in FIG. 3 is subjected to the coating step and removal step described below, a carbon conductive film composite 105 shown in FIG. 4 is obtained.

[0053] [Coating process] The coating step is a step of applying a CNT ink 34 containing single-walled carbon nanotubes 35, a dispersant, and a dispersion solvent onto a formation substrate 40 by spin coating to form a CNT coating film 39.

[0054] The single-walled carbon nanotubes 35 contained in the CNT ink 34 are the same as those described in the above [Conductive film laminate], and therefore a description thereof will be omitted.

[0055] Examples of dispersants that can be used include ethyl cellulose, sodium dodecyl sulfate, sodium dodecyl benzene sulfate, etc. Ethyl cellulose is preferred because it is easy to adjust the viscosity of the CNT ink 34 and makes it easy to disperse the single-walled carbon nanotubes 35 uniformly.

[0056] Examples of the dispersion solvent include N-methylpyrrolidone, dimethylformamide, etc. N-methylpyrrolidone is preferred because it provides excellent solution stability.

[0057] The concentration of the single-walled carbon nanotubes 35 in the CNT ink 34 is, for example, 0.01 to 0.5 mass%, preferably 0.05 to 0.2 mass%, and more preferably 0.08 to 0.12 mass% in 100 mass% of the CNT ink 34. If the concentration of the single-walled carbon nanotubes 35 is within the above range, it is preferable because a uniform SWCNT film can be easily formed.

[0058] The concentration of the dispersant in the CNT ink 34 is, for example, 0.05 to 3 mass%, preferably 0.5 to 1.5 mass%, and more preferably 0.8 to 1.2 mass% based on 100 mass% of the CNT ink 34. If the concentration of the single-walled carbon nanotubes 35 is within the above range, the dispersion efficiency of the single-walled carbon nanotubes is high, which is preferable.

[0059] 3 becomes a CNT coating film 39 that covers the surface of the forming substrate 40. The components of the CNT coating film 39 may be the same as those of the CNT ink 34, or may be CNT ink 34 from which part or all of the dispersion solvent and the like have been removed.

[0060] [Removal process] The removal step is a step of removing the dispersant and dispersion solvent derived from the CNT ink 34 from the CNT coating film 39. Note that if no dispersion solvent is present in the CNT coating film 39, the removal step is a step of removing the dispersant from the CNT coating film 39.

[0061] In the removal step, for example, the CNT coating film 39 is heat-treated at 350° C. or higher, preferably 350 to 400° C. If the heat treatment temperature is within the above range, the dispersant and solvent are efficiently removed and heat damage to the CNT coating film 39 is small, which is preferable.

[0062] In the first laminate production step, first, a coating step and a removal step are performed to obtain the carbon conductive film composite 105 shown in Fig. 4. In the first laminate production step, next, an adhesive layer 20B is formed on the surface of the carbon conductive film 30A of the carbon conductive film composite 105 by a known method, thereby obtaining the first laminate 110 shown in Fig. 2.

[0063] (Thermocompression bonding process) The thermocompression bonding step is a step in which the adhesive layer 20B (20) of the first laminate 110 is brought into contact with the laminate-receiving substrate 10, and then thermocompression bonding is performed to produce the second laminate 120.

[0064] Fig. 6 is a cross-sectional view showing an example of a pre-thermocompression-bonded composite 115 according to this embodiment. The pre-thermocompression-bonded composite 115A (115) shown in Fig. 6 includes a laminated substrate 10, an adhesive layer 20B (20) formed on the surface of the laminated substrate 10, and a carbon conductive film 30A (30) formed on the surface of the adhesive layer 20B. The pre-thermocompression-bonded composite 115A is a laminate before thermocompression bonding in the thermocompression bonding step. The pre-thermocompression-bonded composite 115A is a precursor of a second laminate 120, which is a laminate after thermocompression bonding in the thermocompression bonding step.

[0065] Fig. 7 is a cross-sectional view showing an example of a second laminate 120 according to this embodiment. The second laminate 120A (120) shown in Fig. 7 includes a laminate-receiving substrate 10, an adhesive layer 20A (20) formed on the surface of the laminate-receiving substrate 10, and a carbon conductive film 30A (30) formed on the surface of the adhesive layer 20A. The second laminate 120A is a laminate after thermocompression bonding in a thermocompression bonding step.

[0066] When the pre-thermocompression-bonded composite 115A shown in Fig. 6 is subjected to thermocompression bonding, a second laminate 120A shown in Fig. 7 is obtained. Fig. 8 is an optical photograph showing an example of the second laminate 120A (120) according to this embodiment.

[0067] When the temperature of the thermocompression bonding is equal to or higher than the glass transition temperature of the laminated substrate 10, preferably equal to or higher than the glass transition temperature of the laminated substrate 10 + 5°C, entanglement easily occurs between the molecules of the resin constituting the laminated substrate 10 and the molecules of the adhesive constituting the adhesive layer 20B (20). When entanglement occurs in this manner, the laminated substrate 10 and the adhesive layer 20B (20A, 20) tend to be strongly bonded together, which is preferable.

[0068] Furthermore, the temperature for thermocompression bonding is preferably equal to or higher than the glass transition temperature of the adhesive constituting the adhesive layer 20B (20), and more preferably equal to or higher than the glass transition temperature of the adhesive + 5°C. When the temperature for thermocompression bonding is within the above range, entanglement easily occurs between the molecules of the adhesive constituting the adhesive layer 20B and the molecules of the resin constituting the laminated substrate 10 and one or more of the single-walled carbon nanotubes 35 constituting the SWCNT film 30A. When entanglement occurs in this manner, the laminated substrate 10 and one or more of the adhesive layer 20B (20A, 20) and SWCNT film 30A tend to be strongly bonded to each other, which is preferable.

[0069] The temperature for the thermocompression bonding is, for example, 100° C. or higher, preferably 120 to 130° C. If the temperature for thermocompression bonding is within the above range, the layers are firmly bonded together, and the thermal history due to heating is reduced, which is preferable as it is possible to suppress deterioration.

[0070] For example, when PET with a glass transition temperature of 69°C is used as the laminated substrate 10 and PMMA with a glass transition temperature of 90°C is used as the adhesive, the thermocompression temperature is set to, for example, 100°C or higher. A thermocompression temperature within the above range is preferable because it facilitates strong bonding between the laminated substrate 10 and one or more of the adhesive layer 20B (20A, 20) and the SWCNT film 30A.

[0071] The applied load for the thermocompression bonding can be, for example, 2 to 8 kN, and preferably 4 to 6 kN. The pressure application time for the thermocompression bonding can be, for example, 30 to 75 seconds, and preferably 45 to 60 seconds.

[0072] The thermocompression bonding step can be carried out by, for example, TOM (Three Dimension Overlay Method, three-dimensional surface decoration) molding.

[0073] The temperature for thermocompression bonding in the TOM molding method is, for example, 100° C. or higher, preferably 120 to 130° C. If the temperature for thermocompression bonding is within the above range, the laminated substrate 10 can easily follow the elongation and the adhesive effect of the adhesive is effectively exhibited, which is preferable because the adhesion between the laminated substrate 10 and the adhesive layer 20B is stable.

[0074] In the TOM molding method, the elongation of the laminated substrate 10 during thermocompression bonding is set to, for example, 100% or more, such as 100 to 150%. If the elongation of the laminated substrate 10 is within the above range, it is preferable because it is easier to obtain a stable second laminate 120A without film tearing, wrinkling, peeling at the edges, or blisters. Here, "100% elongation" of the laminated substrate 10 means that the length of the laminated substrate 10 after elongation is twice the length of the laminated substrate 10 before elongation.

[0075] (etching process) The etching step is a step of etching the substrate 40 for forming the second laminate 120A(120) to produce the conductive film laminate 1A(1).

[0076] Specifically, the etching step is a step of etching the forming substrate 40 by immersing the second laminate 120 in an etchant 50 that etches the metal contained in the forming substrate 40. For example, when the forming substrate 40 is a Cu plate made of a Cu-containing metal, the etching step is a step of etching the forming substrate 40 by immersing the second laminate 120A in an etchant 50 that etches Cu.

[0077] The etchant 50 for etching Cu is not particularly limited as long as it can etch Cu and does not cause deterioration of the material of the laminated substrate 10, such as PET. Examples of the etchant 50 for etching Cu include an aqueous iron nitrate solution, an aqueous iron chloride solution, and acids such as hydrochloric acid and sulfuric acid. Among these, an etchant 50 made of one or more of an aqueous iron nitrate solution and an aqueous iron chloride solution is preferred because it has little or no adverse effect on the material of the laminated substrate 10, such as PET.

[0078] For example, one or more of an aqueous iron nitrate solution and an aqueous iron chloride solution are used as the etchant 50. The concentration of the aqueous iron nitrate solution or the aqueous iron chloride solution is, for example, 0.5 to 7.0 M. Note that, if the etchant 50 has a high concentration of metal ions, it is preferable because the metal ions are more likely to be contained in the adhesive layer 20A of the conductive film laminate 1A.

[0079] 9 is a cross-sectional view showing an example of an etching step of the second stack 120 according to this embodiment. As shown in Fig. 9, the etching step is performed by immersing the second stack 120 in an etching bath 200 filled with an etchant 50, for example.

[0080] 9 specifically shows an example in which metal ions 60B(60) are generated from the formation substrate 40 by etching the formation substrate 40 with an etchant 50 containing metal ions 60A(60).

[0081] 9, when the formation substrate 40 of the second laminate 120 is etched with the etchant 50, it releases metal ions 60B into the etchant 50. Therefore, as the etching progresses in this step, the etchant 50 contains metal ions 60A derived from the etchant 50 and metal ions 60B derived from the formation substrate 40.

[0082] When the etching further progresses in this step and the formation substrate 40 is completely removed, a conductive film laminate 1A including the laminate-receiving substrate 10, the adhesive layer 20A, and the SWCNT film (carbon conductive film) 30A shown in Fig. 1 is obtained in the etchant 50. Fig. 10 is an SEM photograph of the surface of an example of the SWCNT film (carbon conductive film) 30A according to this embodiment.

[0083] As shown in Figure 10, the SWCNT film (carbon conductive film) 30A typically has numerous voids. Therefore, metal ions 60 (60A, 60B), such as metal ions 60A and 60B, in the etchant 50 penetrate into the SWCNT film (carbon conductive film) 30A and then into the adhesive layer 20B. When the metal ions 60 penetrate into the adhesive layer 20B in this manner, an adhesive layer 20A containing the metal ions 60 is obtained. The metal ions 60 contained in the adhesive layer 20B typically have a positive charge. Note that when the adhesive layer 20B contains a cured product of a water-absorbent modified acrylic adhesive having a highly polar functional group or the like, the metal ions 60 are more likely to penetrate into the adhesive layer 20B.

[0084] The metal ions 60 contained in the adhesive layer 20A act as acceptors (P-type impurities) at the interface with the SWCNT film (carbon conductive film) 30A. Therefore, in the adhesive layer 20A containing the metal ions 60, a doping effect occurs in which electrons move back and forth at the interface between the adhesive layer 20A and the SWCNT film (carbon conductive film) 30A, improving the conductive effect of the SWCNT film (carbon conductive film) 30A of the conductive film laminate 1A. Note that if the adhesive layer 20B contains a cured product of a modified acrylic adhesive that has highly polar functional groups and is water-absorbent, the doping effect is more pronounced, and the conductive effect of the SWCNT film (carbon conductive film) 30A of the conductive film laminate 1A is further improved, which is preferable.

[0085] (effect) According to the method for manufacturing a conductive film laminate according to this embodiment, it is possible to provide a method for manufacturing a conductive film laminate 1A with stable film quality.

[0086] Furthermore, the method for manufacturing a conductive film laminate according to this embodiment, in which the etching step is performed after the thermocompression bonding step, does not require the conventional step of transferring the carbon conductive film in water. [Example]

[0087] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0088] [Example 1] (First laminate manufacturing process) A Cu plate (125 μm thick) was prepared as the substrate. Furthermore, the raw materials for the CNT ink were prepared: SWCNT eDIPS EC1.5 (Meijo Nanocarbon Co., Ltd., center diameter 1-3 nm), ethyl cellulose as a dispersant, and N-methylpyrrolidone as a dispersion solvent. The CNT ink was prepared by mixing eDIPS EC1.5, ethyl cellulose, and N-methylpyrrolidone so that the eDIPS EC1.5 content was 0.1% by mass and the ethyl cellulose content was 1% by mass.

[0089] [Coating process] The CNT ink was applied to the surface of a Cu plate by spin coating, forming a 150 nm thick CNT coating film on the surface of the Cu plate.

[0090] [Removal process] The Cu plate with the CNT coating formed on it was heat-treated at 350°C for 30 minutes to obtain a carbon conductive film composite with a 150nm thick SWCNT film formed on the surface of the Cu plate. Figure 5 shows an SEM photograph of the surface of the SWCNT film.

[0091] The adhesive layer 20B was prepared using modified acrylic adhesive G25 manufactured by Nichiei Shinka Co., Ltd. G25 had a 25 μm thick modified acrylic adhesive layer, a 38 μm thick PET release layer covering one side of the adhesive layer, and a 75 μm thick PET release layer covering the other side of the adhesive layer. The modified acrylic adhesive layer was a sheet made of modified PMMA (glass transition temperature: 90°C).

[0092] A 25 μm thick modified acrylic adhesive layer of G25 was adhered to the surface of the SWCNT film of the carbon conductive film composite to obtain a first laminate comprising a Cu plate, an SWCNT film, and a modified acrylic adhesive layer.

[0093] (Thermocompression bonding process) A PET plate (thickness: 125 μm, glass transition temperature: 69° C.) was prepared as the substrate to be laminated. The modified acrylic adhesive layer of the first laminate was placed in contact with the surface of the PET plate, and TOM molding was performed under the following conditions: heating temperature 100°C, applied load 5 kN, and pressure time 60 seconds (1 minute). A second laminate comprising a PET plate, a modified acrylic adhesive layer, a SWCNT film, and a Cu plate was obtained by TOM molding. Figure 8 shows an optical photograph of the second laminate.

[0094] (etching process) An etching bath 200 shown in Figure 9 was prepared, and a Cu etchant (6.9 M iron chloride solution) was stored in the bath at 20°C. The second laminate was immersed in the Cu etchant for 18 minutes, and the Cu plate of the second laminate was removed by etching, resulting in a conductive film laminate comprising a PET plate, a modified acrylic adhesive layer, and an SWCNT film. Figure 10 shows an SEM photograph of the surface of the SWCNT film (carbon conductive film) of the conductive film laminate.

[0095] (evaluation) The electrical properties of the resulting conductive film laminate were measured.

[0096] <Electrical conductivity> The electrical conductivity of the SWCNT film (carbon conductive film) of the obtained conductive film laminate was measured. The test piece shown in Fig. 11 was produced from the obtained conductive film laminate. For the test piece shown in Fig. 11, Ag paste was applied to the four corners of the surface of the conductive film laminate on the SWCNT film (carbon conductive film) side, to produce four Ag terminals 210. The electrical conductivity of the SWCNT film (carbon conductive film) is 3.4×10 5 It was S / m. The surface sheet resistance of the SWCNT film (carbon conductive film) was 20 Ω / sq.

[0097] [Example 2] A conductive film laminate was obtained in the same manner as in Example 1, except that an aqueous solution of iron nitrate (0.52 M) was used as the Cu etchant instead of the aqueous solution of iron chloride (6.9 M).

[0098] (evaluation) The electrical conductivity of the SWCNT film (carbon conductive film) of the conductive film laminate was measured in the same manner as in Example 1. The electrical conductivity of the SWCNT film (carbon conductive film) is 1.4×10 5 It was S / m. The surface sheet resistance of the SWCNT film (carbon conductive film) was 46 Ω / sq.

[0099] [Comparative Example 1] A conductive film laminate having the same layer structure as in Example 1 was obtained using a conventional PMMA support transfer method.

[0100] (First laminate manufacturing process) [Coating process] First, the coating step was carried out in the same manner as in Example 1.

[0101] [Removal process] Next, the Cu plate with the CNT coating formed thereon was heat-treated at 350°C for 30 minutes to obtain a carbon conductive film composite with a 150 nm thick SWCNT film formed on the surface of the Cu plate.

[0102] A PMMA adhesive support sheet was formed as adhesive layer 20 on the SWCNT film of the carbon conductive film composite using a spin coating method. First, a PMMA dispersion was prepared by mixing PMMA with ethyl lactate as a solvent. The PMMA dispersion was prepared so that it contained 4% by mass of PMMA in 100% by mass. Next, a PMMA dispersion film was formed on the SWCNT film of the carbon conductive film composite using spin coating, and then heat-treated at 180°C to form a 200 nm thick PMMA adhesive support sheet on the SWCNT film. This resulted in a first laminate comprising the Cu plate, the SWCNT film, and the PMMA adhesive support sheet.

[0103] (etching process) An etching tank 200 shown in Fig. 9 was prepared, and a Cu etchant, an aqueous solution of iron chloride (6.9 M), was stored in the tank at 20°C. The first laminate was immersed in the Cu etchant for 18 minutes, and the Cu plate of the first laminate was removed by etching, yielding a conductive film laminate comprising a PMMA adhesive support sheet and a SWCNT film.

[0104] (Underwater transfer process) A PET plate (thickness: 125 μm, glass transition temperature: 69° C.) was prepared as the substrate to be laminated. A water tank filled with ultrapure water was prepared. In the ultrapure water, the SWCNT film of the conductive film laminate was transferred onto the surface of a PET plate to produce a transfer body in which the PMMA adhesive support sheet, SWCNT film, and PET plate were laminated in that order.

[0105] (Cleaning process) Toluene was poured onto the transfer body to remove the PMMA adhesive support sheet from the transfer body, yielding a two-layer conductor in which the SWCNT film and the PET plate were laminated in this order.

[0106] (evaluation) The electrical conductivity of the SWCNT film (carbon conductive film) of the double-layer conductor was measured in the same manner as in Example 1. The test piece was prepared by applying Ag paste to the four corners of the surface of the SWCNT film (carbon conductive film) side of the double-layer conductor to prepare four Ag terminals. The electrical conductivity of the SWCNT film (carbon conductive film) is 7.8×10 4 It was S / m. The surface sheet resistance of the SWCNT film (carbon conductive film) was 85 Ω / sq.

[0107] Although the present embodiment has been described above, the present embodiment is not limited to this, and various modifications are possible within the scope of the gist of the present embodiment. [Explanation of symbols]

[0108] 1. 1A Conductive film laminate 10 Laminated base material 20 Adhesive layer 20A Metal ion-containing adhesive layer 20B Metal ion-free adhesive layer 30 Carbon conductive film 30A SWCNT film (carbon conductive film) 34 CNT ink 35 Single-walled carbon nanotubes 39 CNT coating film 40 Formation substrate 50 Etchant 60, 60A, 60B metal ions 100 CNT coating composite 105 Carbon conductive film composite 110 First laminate 115 Pre-thermocompression composite 120, 120A Second laminate 200 Etching bath 210 Ag terminal

Claims

1. A method for manufacturing a conductive film laminate comprising a substrate to be laminated, an adhesive layer formed on a surface of the substrate to be laminated, and a carbon conductive film formed on the surface of the adhesive layer, the method comprising: a first laminate fabrication step of fabricating a first laminate including a formation substrate for forming the carbon conductive film on a surface thereof, the carbon conductive film formed on the surface of the formation substrate, and an adhesive layer formed on the surface of the carbon conductive film; a thermocompression bonding step of contacting the adhesive layer of the first laminate with the laminated base material and then performing thermocompression bonding to produce a second laminate; an etching step of etching the formation substrate of the second laminate to produce the conductive film laminate; Equipped with The method for manufacturing a conductive film laminate, wherein the carbon conductive film constituting the first laminate is a SWCNT film that is a network structure of single-walled carbon nanotubes.

2. The method for producing a conductive film laminate according to claim 1 , wherein the temperature of the thermocompression bonding step is equal to or higher than the glass transition temperature of the substrate to be laminated.

3. 3. The method for producing a conductive film laminate according to claim 1, wherein the temperature of the thermocompression bonding step is equal to or higher than the glass transition temperature of the adhesive that constitutes the adhesive layer.

4. 4. The method for producing a conductive film laminate according to claim 1, wherein the substrate to be laminated is made of a PET resin.

5. 5. The method for producing a conductive film laminate according to claim 1, wherein the adhesive layer contains a cured product of an acrylic adhesive.

6. The method for producing a conductive film laminate according to claim 5, wherein the cured product of the acrylic adhesive is a cured product of a water-absorbent acrylic adhesive.

7. 7. The method for producing a conductive film laminate according to claim 1, wherein the thermocompression bonding in the thermocompression bonding step is performed by TOM molding.

8. the formation substrate is a Cu plate made of a Cu-containing metal, 8. The method for manufacturing a conductive film laminate according to claim 1, wherein the etching step etches the formation substrate by immersing the second laminate in an etchant that etches Cu.

9. 9. The method for producing a conductive film laminate according to claim 8, wherein the etchant comprises at least one of an aqueous solution of iron nitrate and an aqueous solution of iron chloride.

10. The SWCNT film is a coating step of applying a CNT ink containing single-walled carbon nanotubes, a dispersant, and a dispersion solvent onto the formation substrate by a spin coating method to form a CNT coating film; a removal step of removing the dispersant and the dispersion solvent from the CNT coating film; The method for producing the conductive film laminate according to claim 1 , wherein the conductive film laminate is formed through the steps of:

11. The method for producing a conductive film laminate according to claim 10 , wherein the removing step comprises heat treating the CNT coating film at 350° C. or higher.

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