JP2020142523A - Laminate, method for producing conductive base material using the same, and method for producing electronic device - Google Patents

Abstract

To provide a laminate that allows transfer of a porous conductive layer having excellent foil breakage resistance and transferability, and excellent conductivity.SOLUTION: A laminate 1 contains a base material 2, a porous conductive layer 3 formed on the base material 2, and an adhesion layer 4 formed on the porous conductive layer 3. The porous conductive layer 3 is a sintered body of metal nanoparticles, and the porous conductive layer 3 is formed over the entire surface of the base material 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laminate having a conductive layer, and a method for manufacturing a conductive base material and a method for manufacturing an electronic device using the laminate.

Conventionally, as a method of forming a metal layer as a conductive layer or a decorative layer on a base material, for example, a method using a transfer sheet is known (see Patent Documents 1 to 5).

Patent Document 1 proposes a method for forming an antenna terminal portion using a metal vapor deposition layer transfer sheet in which a protective layer, a metal vapor deposition layer and an adhesive layer are laminated on a base material. In the case of the metal vapor deposition layer as in Patent Document 1, heat resistance is required for the base layer of the metal vapor deposition layer. Therefore, when an inexpensive general-purpose plastic film such as PET film is used as the base material, there is a problem that the film forming process, the metal type, the film thickness, etc. are limited due to the low heat resistance, and the protective layer is placed on the base material. Heat resistance is ensured by forming such as. On the other hand, as the base material, a base material having high heat resistance such as a polyimide film, a PEN film, or a glass film can be used, but these base materials are expensive and suitable as a base material for a transfer sheet to be peeled off. I can't say that there is.

Patent Document 2 has a release sheet as a base material, an insulator layer provided on the release sheet, and a metal foil arranged in contact with the insulator layer, and the metal foil is attached to the release sheet. A metal leaf sheet for transfer, which is attached by the attractive force of static electricity generated between the insulator layer and the insulator layer, has been proposed. In the case of a metal foil as in Patent Document 2, there is a problem that the adhesion to the base material is low, and the adhesion is ensured by forming a resin layer such as an insulator layer on the base material.

Patent Document 3 uses a heat transfer film having a resin film, a metal foil provided on the surface of the resin film via an adhesive, and a heat-curable adhesive coated on the metal foil. Manufacture of a metal foil fuse that transfers a metal foil onto an insulating substrate via a heat-curable adhesive to the pattern shape of the fuse element of the transfer mold using a transfer mold having a convex fuse element pattern. A law has been proposed. Also in this case, the adhesion between the resin film and the metal foil is ensured by providing the metal foil on the surface of the resin film via an adhesive.

By the way, the transfer sheet is required to have foil breakability. However, since the metal vapor deposition layer and the metal foil have ductility, there is a problem that burrs are generated during transfer and the foil breakability is poor. Further, in the metal vapor deposition layer, crystal grains may grow large, and in that case, the foil breakability naturally deteriorates. In order to improve the foil breakability, a method has been proposed in which a transfer sheet is sandwiched between dies having irregularities, cut by applying stress, and then the transfer is performed, but the process becomes complicated.

Further, since metal generally has a high thermal conductivity, heat tends to diffuse easily in a metal vapor deposition layer or a metal foil, and the energy required for transfer tends to increase, which may distort the shape of the transfer sheet.

Further, when the transfer sheet is transferred to the transferred body, in order to bond the metal vapor deposition layer or the metal foil to the transferred body, for example, when a heat sealant such as a thermoplastic resin is used as the adhesive layer, it is thermoplastic. Heat above the glass transition temperature of the resin. At this time, the adhesive force between the transferred body and the metal vapor deposition layer or the metal foil becomes larger than the adhesion force between the base material and the metal vapor deposition layer or the metal foil, so that thermal transfer is realized. In this case, since there is a limit to adjusting the above-mentioned adhesion force only with the heat sealant, the adhesion force between the transferred object and the metal vapor deposition layer or the metal foil is adjusted to the adhesion between the base material and the metal vapor deposition layer or the metal foil. It has been proposed to form fine irregularities such as roughening the contact surface between the metal vapor deposition layer and the adhesive layer of the metal foil in order to make the force larger than the force, but the process becomes complicated.

In Patent Document 4, a donor element in which a light absorption layer and a metal nanoparticle layer are laminated on a donor substrate which is a base material is used, and the donor element and the receiving substrate are placed in contact with each other and irradiated with a laser from the donor element side. A method has been proposed in which a pattern of an electric conductor is formed on a receiving substrate by annealing and transferring the metal nanoparticle layer. However, since metal nanoparticles are used as the conductive material in this method, the electrical resistance at the interface between the particles is a problem, and in order to achieve the desired conductivity, the metal nanoparticles can be annealed at a high temperature. is necessary. Therefore, the base material needs to withstand the high heat of laser annealing, the base material is limited, and it becomes difficult to use an inexpensive general-purpose plastic film. In addition, an expensive base material having high heat resistance must be used as the base material to be peeled off, resulting in high cost.

On the other hand, in Patent Document 5, a transfer sheet in which a sintered body layer of metal ultrafine particles is formed on a base material is used, and metal ultrafine particles are baked on a substrate to be transferred on which an adhesive layer is formed on the surface. A method of forming a wiring pattern composed of a bundling layer has been proposed. In this method, by using ultrafine metal particles, sintering can be performed even at a relatively low temperature.
However, the conductivity of the ultrafine metal particles may decrease due to oxidation, and the conductivity may decrease when the sintered body layers of the ultrafine metal particles are transferred to the substrate to be transferred.

JP-A-2007-324641 Japanese Unexamined Patent Publication No. 7-101198 Japanese Unexamined Patent Publication No. 5-314888 Japanese Patent Publication No. 2008-541481 Japanese Unexamined Patent Publication No. 2004-247772

The present invention has been made in view of the above problems, and is a laminate capable of transferring a porous conductive layer having excellent foil breakability and transferability and good conductivity, and a conductive base material using the same. The main purpose is to provide a method for manufacturing an electronic device and a method for manufacturing an electronic device.

In order to achieve the above object, the present invention is characterized by having a base material, a porous conductive layer formed on the base material, and an adhesive layer formed on the porous conductive layer. Provide a laminate.

In the present invention, a component derived from the adhesive layer, for example, a resin contained in the adhesive layer can be inserted into the pores of the porous conductive layer. Therefore, it is possible to prevent thermal diffusion from occurring, which is advantageous for thermal transfer. In addition, the adhesion between the porous conductive layer and the adhesive layer can be enhanced, and excellent transferability can be obtained. Further, the porous conductive layer can be protected by the resin contained in the adhesive layer, oxidation of the porous conductive layer at the time of transfer can be suppressed, and a decrease in conductivity can be suppressed.
Further, in the present invention, since it has a porous conductive layer, brittleness is imparted, and good foil breakability and resolution can be obtained. Further, since the porous conductive layer can be formed by sintering metal particles at a low temperature, it is less likely to damage the base material, it is not necessary to use a base material having high heat resistance, and a group having low heat resistance. Wood can also be used.
Further, by using the laminate of the present invention, a conductive base material can be easily produced.

Further, in the present invention, it is preferable that the base material is a resin base material. As described above, in the present invention, a base material having low heat resistance can also be used, and it is very useful in that an inexpensive general-purpose plastic resin base material can be used.

Further, in the present invention, a protective layer may be formed between the base material and the porous conductive layer. After transfer, the porous conductive layer can be protected by the protective layer. Further, the porous conductive layer can be insulated by using the protective layer having an insulating property.

The present invention also includes a preparatory step for preparing the above-mentioned laminate and a transfer step for transferring the adhesive layer and the porous conductive layer of the laminate onto the substrate to be transferred. Providing a manufacturing method for.

Since the above-mentioned laminate is used in the present invention, it is excellent in foil breakability, resolution, and transferability. In addition, a porous conductive layer having good conductivity can be obtained even after transfer. Further, the conductive base material can be easily produced.

In the above invention, in the above transfer step, the pattern of the adhesive layer and the porous conductive layer of the laminate may be transferred onto the transfer base material. It is possible to obtain a conductive base material in which a pattern of a porous conductive layer is formed on the base material to be transferred.

Further, the present invention comprises a preparatory step for preparing the above-mentioned laminate, and the above-mentioned laminate is placed in a molding mold, and a molten resin for a base material to be transferred is injected into the mold and solidified to be solidified to be a base material to be transferred. A method for producing a conductive base material, which comprises a molding and transfer step of transferring the laminate to the base material to be transferred at the same time as molding, and a peeling step of peeling the base material of the laminate. provide.

In the present invention, since the above-mentioned laminate is used, it is excellent in foil breakability and transferability. In addition, a porous conductive layer having good conductivity can be obtained even after transfer. Further, a three-dimensional conductive base material can be easily produced.

Further, the present invention provides a method for manufacturing an electronic device, which comprises a step for manufacturing a conductive base material by the above-mentioned method for manufacturing a conductive base material.

In the present invention, since the conductive base material is produced by the above-mentioned method for producing a conductive base material, a porous conductive layer having good conductivity can be formed. Further, for example, when forming a pattern of a porous conductive layer, a high-resolution pattern can be formed.

The laminate of the present invention is excellent in foil breakability and transferability, and has an effect that it is possible to transfer a porous conductive layer having good conductivity.

It is the schematic sectional drawing which shows an example of the laminated body of this invention. It is a process drawing which shows an example of the manufacturing method of the conductive base material of this invention. It is a process drawing which shows another example of the manufacturing method of the conductive base material of this invention. It is schematic cross-sectional view which shows the laminated body of this invention and another example of a conductive base material. It is schematic cross-sectional view which shows the laminated body of this invention and another example of a conductive base material. It is a process drawing which shows another example of the manufacturing method of the conductive base material of this invention. It is schematic cross-sectional view which shows the laminated body of this invention and another example of a conductive base material. It is a process drawing which shows another example of the manufacturing method of the conductive base material of this invention. It is a process drawing which shows another example of the manufacturing method of the conductive base material of this invention.

Hereinafter, a method for producing a laminate, a conductive base material, and a method for producing an electronic device of the present invention will be described in detail.

A. Laminated body The laminated body of the present invention is characterized by having a base material, a porous conductive layer formed on the base material, and an adhesive layer formed on the porous conductive layer. ..

The laminate of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an example of the laminated body of the present invention. As shown in FIG. 1, the laminate 1 has a base material 2, a porous conductive layer 3 formed on the base material 2, and an adhesive layer 4 formed on the porous conductive layer 3. There is.

2 (a) to 2 (c) are process diagrams showing an example of a method for producing a conductive base material using the laminate of the present invention, and are examples of using the laminate shown in FIG. First, as shown in FIG. 2A, the laminate 1 and the transfer base material 11 are prepared. Next, as shown in FIG. 2B, the adhesive layer 4 of the laminated body 1 and the substrate to be transferred 11 are arranged so as to be in contact with each other, and thermocompression bonding is performed from the laminated body 1 side. Then, as shown in FIG. 2C, the base material 2 is peeled off. As a result, the adhesive layer 4 and the porous conductive layer 3 are transferred to the transfer base material 11 in the thermocompression-bonded region, and the conductive base material 10 is obtained.

3 (a) to 3 (c) are process diagrams showing another example of the method for producing a conductive base material using the laminate of the present invention, and are examples of using the laminate shown in FIG. First, as shown in FIG. 3A, the laminate 1 and the substrate to be transferred 11 are prepared. Next, as shown in FIG. 3B, the adhesive layer 4 of the laminated body 1 and the substrate to be transferred 11 are arranged so as to be in contact with each other, and thermocompression bonding is performed from the laminated body 1 side. At this time, thermocompression bonding is partially performed by the thermal head 12 or the like of the thermal head printer. Then, as shown in FIG. 3C, the base material 2 side is peeled off. As a result, the adhesive layer 4 and the porous conductive layer 3 are transferred to the transfer base material 11 in the thermocompression-bonded region, and the conductive base material 10 having the pattern of the adhesive layer 4 and the porous conductive layer 3 is obtained.

In the present invention, a component derived from the adhesive layer, for example, a resin contained in the adhesive layer can be allowed to enter inside the pores of the porous conductive layer, and apparently a mixture of the porous conductive layer and the component derived from the adhesive layer. Therefore, it is possible to prevent heat diffusion from occurring. Therefore, when the laminate of the present invention is transferred to the substrate to be transferred, heat does not easily escape, so that it is not necessary to overheat, which is advantageous for thermal transfer.

Further, in the present invention, as described above, since the component derived from the adhesive layer can be allowed to enter the inside of the pores of the porous conductive layer, not only the surface area where the porous conductive layer and the adhesive layer come into contact with each other is increased, but also. The anchor effect can enhance the adhesion between the porous conductive layer and the adhesive layer. Therefore, when the laminate of the present invention is transferred to the substrate to be transferred, the adhesive layer and the porous conductive layer can be satisfactorily transferred to the substrate to be transferred, and excellent transferability can be obtained.

Further, as will be described later, in the porous conductive layer, the metal particles are sintered and fused to each other, so that the region where the component derived from the adhesive layer is contained inside the pores of the porous conductive layer is also conductive. Contribute to. Therefore, the adhesion to the adhesive layer can be improved without lowering the conductivity.

In addition, conductive materials such as metals and metal oxides may have reduced conductivity due to oxidation, and when the laminate of the present invention is transferred to a substrate to be transferred, the conductivity of the porous conductive layer is reduced. There is a risk of reduced sex. On the other hand, in the present invention, as described above, the resin contained in the adhesive layer can be inserted into the pores of the porous conductive layer, so that the laminate of the present invention is transferred to the substrate to be transferred. In this case, the porous conductive layer can be protected by the resin contained in the adhesive layer, and the oxidation of the porous conductive layer can be suppressed. Therefore, it is possible to suppress a decrease in the conductivity of the porous conductive layer during transfer.

Further, in the present invention, since the porous conductive layer is porous, brittleness is imparted, so that unlike the conventional vapor-deposited layer, less burrs are generated during transfer and no large crystal grains are contained. Therefore, good foil breakability can be obtained. Further, as illustrated in FIGS. 3A to 3C, when the pattern of the adhesive layer and the porous conductive layer of the laminate of the present invention is transferred to the substrate to be transferred, the transfer can be performed with high resolution. it can.

Here, it is known that metal particles are sintered at a low temperature when the particle size is reduced. In the present invention, when such metal particles are made into nanoparticles, the metal particles are sintered at a low temperature to form a porous conductive layer by utilizing the property of sintering the metal particles at a temperature significantly lower than the melting point of the metal particles. Can be formed. Therefore, the base material is less likely to be damaged, it is not necessary to use a base material having high heat resistance, and a base material having low heat resistance can also be used. In particular, it is very useful in that an inexpensive general-purpose plastic resin base material such as polyethylene terephthalate can be used.

Further, in the present invention, the porous conductive layer can be formed by, for example, applying a metal particle dispersion liquid containing metal particles on a base material and firing it, and the porosity has good adhesion to the base material. A conductive layer can be obtained. Therefore, it is not necessary to form another layer or apply a surface treatment on the base material in order to improve the adhesion.

Further, since the porous conductive layer can be formed on the transfer base material by transferring the laminate of the present invention to the transfer base material, the porous conductive layer is conventionally formed as the transfer base material. Substrates that were difficult to do can also be used. Therefore, it is possible to obtain an inexpensive general-purpose plastic resin base material such as polyethylene terephthalate, or a conductive base material in which a porous conductive layer is formed on a paper base material or the like. Furthermore, it is possible to form a porous conductive layer on the substrate to be transferred, which is a three-dimensional object.

Hereinafter, each configuration in the laminated body of the present invention will be described.

1. 1. Porous Conductive Layer The porous conductive layer in the present invention is formed on a base material.

Here, the porous conductive layer means a conductive layer having a large number of pores, and has a larger surface area than a conductive layer having the same volume and no pores.

Examples of the conductive material constituting the porous conductive layer include metals and metal oxides. The conductive material constituting the porous conductive layer may be one kind or two or more kinds.
Of these, metal is preferable. This is because the metal particles can be sintered at a lower temperature to form a porous conductive layer.

Examples of the metal include gold, silver, copper, nickel, platinum, palladium, molybdenum, aluminum, antimony, tin, chromium, indium, gallium, germanium, zinc, titanium and lead. Of these, silver and copper are preferable from the viewpoint of conductivity and cost. The metal may be one kind or two or more kinds.
Examples of the metal oxide include indium tin oxide and antimony-doped tin oxide.

The shape of the pores in the porous conductive layer is not particularly limited as long as the components derived from the adhesive layer can enter at least a part of the pores. It is preferable that at least the surface of the porous conductive layer on the adhesive layer side has communication holes in which a large number of holes are connected to each other.

The porosity of the porous conductive layer may be appropriately adjusted within a range in which both conductivity and adhesion are compatible, and is not particularly limited. Specifically, the porosity of the porous conductive layer is preferably in the range of 5% to 50%, particularly preferably in the range of 10% to 45%, and particularly in the range of 15% to 40%. It is preferably inside. If the porosity is too large, the adhesion between the porous conductive layer and the base material may decrease. On the other hand, if the porosity is too small, the above-mentioned effect due to the components derived from the adhesive layer entering the pores of the porous conductive layer may not be sufficiently obtained.
The porosity of the porous conductive layer represents a portion where the material constituting the porous conductive layer does not exist, and includes a portion in which components derived from the adhesive layer are mixed.

The porosity can be confirmed from the scanning electron microscope (SEM) image of the cross section of the porous conductive layer before the formation of the adhesive layer. Specifically, the area of the pores and the area of the porous conductive layer are calculated from the obtained SEM image, and the porosity in the cross section is obtained by dividing the area of the holes by the area of the porous conductive layer. be able to. The porosity is calculated from the porous conductive layer excluding the base material, and the pores at the interface between the base material and the porous conductive layer are included in the porous conductive layer.
The porosity can also be confirmed from a scanning electron microscope (SEM) image of the cross section of the laminate. Specifically, the area of the pores, the area of the component derived from the adhesive layer, and the area of the porous conductive layer are calculated from the obtained SEM image, and the area of the hole and the area of the component derived from the adhesive layer are calculated. The porosity in the cross section can be determined by dividing the total by the area of the porous conductive layer.
Porosity is similarly obtained for a plurality of cross sections according to the size of the laminated body, and the average value is taken as the porosity of the porous conductive layer.
The porosity can be appropriately adjusted in the method for forming the porous conductive layer described later, depending on the particle size of the metal particles used in the metal particle dispersion, the type of dispersant, the firing conditions, and the like.

The porous conductive layer 3 may be formed on the entire surface of the base material 2 as illustrated in FIG. 1, or may be formed in a pattern on the base material 2 as illustrated in FIG. 4 (a). May be good. When the porous conductive layer 3 is formed in a pattern on the base material 2 as shown in FIG. 4 (a), it is shown in FIG. 4 (b) even if the laminate 1 is not partially transferred. As described above, the pattern of the porous conductive layer 3 can be transferred onto the substrate 11 to be transferred.

The thickness of the porous conductive layer is about 0.01 μm to 50 μm, preferably in the range of 0.05 μm to 10 μm, and particularly preferably in the range of 0.1 μm to 5 μm.

As a method for forming the porous conductive layer, a method of applying a metal particle dispersion liquid containing metal particles on a base material and firing it is used.
In the specification of the present application, the metal particles include particles in an alloy state, particles of a metal compound, and the like in addition to particles in a metal state.

As the metal particles, it is possible to appropriately select and use the metal particles that generate conductivity after firing.
Examples of the metal constituting the metal particles include gold, silver, copper, nickel, platinum, palladium, molybdenum, aluminum, antimony, tin, chromium, indium, gallium, germanium, zinc, titanium, lead and the like. Of these, silver and copper are preferable from the viewpoint of conductivity and cost. The metal constituting the metal particles may be one kind or two or more kinds. Further, those in which two or more kinds of metals form a core-shell structure, those in which the surface of particles in a metallic state is oxidized or nitrided, or the like may be used. The surface of the metal particles may be oxidized, or the metal particles may be oxidized to the inside.
Examples of the metal compound constituting the particles of the metal compound include metal oxides, metal nitrides, metal hydrides, metal hydroxides, and organic metal compounds. It is preferable that these metal compounds are decomposed into a metallic state at the time of firing. For example, particles of a metal compound that is reduced to exhibit conductivity, specifically, particles of a metal compound such as cuprous oxide, cupric oxide, silver oxide, copper nitride, and copper hydride can be mentioned. Further, examples of the metal oxide include indium tin oxide, antimony-doped tin oxide and the like.
The metal particles may be used alone or in combination of two or more.
Of these, particles in a metallic state are preferable. This is because the particles in the metallic state can be sintered at a lower temperature to form a porous conductive layer.

The metal particles are preferably metal nanoparticles. That is, the porous conductive layer is preferably a sintered body of metal nanoparticles. This is because when a metal particle dispersion liquid containing metal nanoparticles is applied and fired to form a porous conductive layer, the pore size and crystal grain size can be controlled within a range suitable for foil breakability. ..

The average particle size of the metal particles is preferably in the range of 1 nm to 200 nm, particularly preferably in the range of 2 nm to 150 nm, and particularly preferably in the range of 2 nm to 100 nm. When the average particle size is within the above range, the dispersion stability of the metal particle dispersion used when forming the porous conductive layer is good, and the conductivity when forming the porous conductive layer is good. In addition, the melting point is kept low, sufficient sintering is possible, and high conductivity can be obtained.
Here, the average particle size of the metal particles is the average primary particle size of the metal particles in the metal particle dispersion liquid, and can be measured from an observation image by a transmission electron microscope.

Examples of the method for preparing metal particles include a physical method obtained by crushing metal powder or metal oxide powder by a mechanochemical method or the like; a CVD method, a vapor deposition method, a sputtering method, a thermal plasma method, a laser method, or the like. Chemical dry method; a method called a chemical wet method by a thermal decomposition method, a chemical reduction method, an electrolysis method, an ultrasonic method, a laser ablation method, a supercritical fluid method, a microwave synthesis method, or the like can be mentioned.

In order to prepare the obtained metal particles into a metal particle dispersion liquid, the metal particles are converted into a water-soluble polymer compound such as polyvinylpyrrolidone, a protective agent such as a graft copolymer polymer compound, a surfactant, a metal or metal oxidation. It is preferable to coat with a compound having a thiol group, an amino group, a hydroxyl group, or a carboxyl group that interacts with the substance. Further, depending on the method for synthesizing metal particles, the thermal decomposition products and oxides of the raw material may protect the particle surface and contribute to the dispersibility. In the case of a wet method such as a thermal decomposition method or a chemical reduction method, the reducing agent or the like may act as a protective agent for metal particles as it is. Further, in order to improve the dispersion stability of the metal particle dispersion liquid, the surface treatment of the metal particles is performed, or a dispersant composed of a polymer compound, an ionic compound, a surfactant or the like is added to the metal particle dispersion liquid. You may.

The dispersion medium used in the metal particle dispersion is not particularly limited as long as it disperses the metal particles, and for example, water or an organic solvent can be used. Examples of the organic solvent include alcohols, ketones, esters, ethers, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons and the like.

Further, a viscosity modifier, a surface tension modifier, a stabilizer, or the like may be added to the metal particle dispersion, if necessary.

The solid content concentration of the metal particle dispersion is preferably in the range of 5% by mass to 95% by mass, particularly in the range of 10% by mass to 90% by mass, particularly in the range of 15% by mass to 85% by mass. It is preferable to have. When the solid content concentration is within the above range, sufficient conductivity can be obtained, the viscosity is sufficiently low, and the metal particle dispersion liquid can be easily applied to the base material.

When the metal particle dispersion liquid is applied onto the base material, the metal particle dispersion liquid may be applied to the entire surface of the base material, or the metal particle dispersion liquid may be applied to the base material in a pattern.
Examples of the method of applying the metal particle dispersion liquid on the substrate include gravure printing, screen printing, spray coating, spin coating, comma coating, bar coating, knife coating, die coating, offset printing, flexographic printing, inkjet printing, and dispenser. Printing and the like can be mentioned. When the metal particle dispersion liquid is applied on the base material in a pattern, gravure printing, flexographic printing, screen printing, and inkjet printing are preferable from the viewpoint of being able to perform fine patterning.

After the application of the metal particle dispersion liquid, it may be dried by a usual method. For example, a drying method of heating at a temperature of about 80 ° C. to 140 ° C. for about 0.1 to 20 minutes using a general oven or the like can be mentioned. The thickness of the coating film after drying can be controlled by adjusting the coating amount, the average particle size of the metal particles, etc., but is usually about 0.01 μm to 100 μm, preferably 0.1 μm to 50 μm. It is within the range.

As a method for firing the coating film of the metal particle dispersion liquid, any method can be used as long as the metal particles can be sintered, and a general firing method can be applied. For example, a method by heat treatment, light treatment, plasma treatment and the like can be mentioned. By firing the coating film, a porous conductive layer made of a sintered body of metal particles can be obtained.
Examples of the heat treatment include hot plate heating, hot air heating, and a hot press method using a hot plate or a hot roll.
Examples of the light treatment include laser treatment, ultraviolet lamp treatment, infrared lamp treatment, far infrared lamp treatment, flash light lamp treatment and the like.
Plasma treatment is a treatment that ionizes gases such as hydrogen, carbon monoxide, ammonia, and alcohol that show reducing properties into a plasma state to generate highly reactive active species. For example, electron cyclotron resonance (ECR) plasma. , Capacitively coupled plasma, inductively coupled plasma, atmospheric pressure plasma, microwave plasma, surface wave plasma generated by application of microwave energy and the like. Above all, surface wave plasma treatment is preferable.
The above firing method can be used in combination of two or more.

Microwave surface wave plasma has the characteristics of high plasma density and low electron temperature, can be fired at a low temperature in a short time, and forms a dense and smooth porous conductive layer. Can be done. In the surface wave plasma, the treated surface is irradiated with plasma having a uniform density in the surface. As a result, as compared with other firing methods, non-uniform film is less likely to be formed such as partial in-plane sintering of metal particles, and grain growth can be prevented, which is extremely difficult. A dense and smooth film can be obtained. Further, since it is not necessary to provide an electrode in the in-plane treatment chamber, contamination of impurities derived from the electrode can be prevented, and damage to the treatment material due to abnormal electric discharge can be prevented. Further, when the resin base material is used, the damage to the resin base material is small, and the damage to other layers is also small.

Further, the microwave surface wave plasma is suitable for enhancing the adhesion of the porous conductive layer to the resin base material. It is presumed that the reason for this is that microwave surface wave plasma tends to generate polar functional groups such as hydroxyl groups and carboxyl groups at the interface between the base material and the porous conductive layer. In particular, when plasma generated in a reducing gas atmosphere is used for a polyester base material, the plasma of the gas having a reducing gas reacts with the ester bond of the base material, and the plasma is changed to the interface side of the base material. It is presumed that the adhesion at the interface between the porous conductive layer and the base material is improved because the quality is improved and many highly polar reactive groups are generated. Therefore, in the microwave surface wave plasma, the substrate and the porous conductivity are compared with the conventional method in which the surface of the substrate is roughened in advance by plasma treatment or the like to improve the adhesion to the porous conductive layer. It is excellent in that it has high adhesion to the layer.

As for the conditions of the microwave surface wave plasma, for example, the conditions described in JP-A-2010-86825 can be applied.

The atmosphere at the time of firing is appropriately selected according to the type of the conductive material constituting the porous conductive layer.
When forming the porous conductive layer containing a metal, the atmosphere is preferably an inert gas or a reducing gas, and more preferably a reducing gas. In the case of a reducing gas atmosphere, the oxide existing on the surface of the metal particles is reduced and removed, and a porous conductive layer having good conductivity can be formed. Therefore, when forming a porous conductive layer containing a metal, metal particles whose surface is oxidized or metal particles whose surface is oxidized can be used as the metal particles.

Examples of the reducing gas include hydrogen, carbon monoxide, ammonia, and a mixed gas thereof. Of these, hydrogen gas is preferable. Hydrogen gas is suitable for removing organic substances adhering to the surface of metal particles.
The reducing gas may be mixed with an inert gas such as nitrogen, helium, argon, neon, krypton, or xenon. In this case, there is an effect that plasma is easily generated.

On the other hand, when the porous conductive layer containing a metal oxide is formed, the atmosphere may be an atmosphere containing an inert gas such as nitrogen or argon and, if necessary, oxygen.

Further, when forming a porous conductive layer containing copper, a method using hydrogen plasma or nitrogen plasma is preferable. In particular, by using hydrogen plasma, a specific resistance of about 3 × 10 ^-6 Ω · cm to 3 × 10 ^-5 Ω · cm can be obtained, and a porous conductive layer having good adhesion to the substrate is formed. Because it can be done.

The firing temperature may be any temperature as long as the metal particles can be sintered, and is appropriately selected according to the type and particle size of the metal particles, the firing method, and the like. Above all, the firing temperature is preferably equal to or lower than the heat resistant temperature of the base material, and for silver particles as an example, it is preferably in the range of 100 ° C. to 150 ° C.
The firing time is appropriately selected according to the type of metal particles, the firing method, and the like. For example, when silver particles are fired by heat treatment, the firing time is preferably in the range of 10 minutes to 120 minutes, particularly preferably in the range of 15 minutes to 40 minutes. Further, for example, when copper particles are fired by hydrogen plasma, the firing time is preferably in the range of 1 minute to 10 minutes, particularly preferably in the range of 2 minutes to 5 minutes.

2. 2. Adhesive layer The adhesive layer in the present invention is formed on the porous conductive layer. The adhesive layer has a function of adhering the porous conductive layer and the substrate to be transferred when the laminate of the present invention is transferred to the substrate to be transferred.

Examples of the material of the adhesive layer include a thermoplastic resin and a photosensitive resin whose adhesiveness or adhesiveness is lowered by light irradiation.

The thermoplastic resin is not particularly limited as long as it can bond the porous conductive layer and the substrate to be transferred, and is appropriately selected depending on the type of the substrate to be transferred to which the laminate is transferred. .. For example, a general thermoplastic resin used for a transfer foil can be used. Further, the thermoplastic resin may be any one as long as it is heated, melted or softened to exhibit adhesiveness or adhesiveness, and a curable resin which is partially cured may be used. Specifically, acrylic resin, urethane resin, amide resin, epoxy resin, styrene-butadiene copolymer, natural rubber, casein, gelatin, rosin resin, terpene resin, phenol resin, styrene resin, silicone resin, styrol resin, polyolefin. , Urethane resin, ionomer resin, vinyl chloride resin, vinyl acetate resin, vinyl chloride-vinyl acetate copolymer resin, polyester resin, polyamide resin and the like, which are known as conventional adhesives can be widely used. The thermoplastic resin may be used alone or in combination of two or more.

As the photosensitive resin whose adhesiveness or adhesiveness is lowered by light irradiation, it is cured by irradiation with light of a specific wavelength such as ultraviolet rays, visible light, infrared rays, etc., and the adhesiveness or adhesiveness is lowered, and the adhesiveness or adhesiveness is lowered. In the light-unirradiated portion, one capable of adhering the porous conductive layer and the substrate to be transferred can be used. Specifically, known materials such as a polyfunctional (meth) acrylic resin formulated with a photopolymerization initiator or an epoxy resin formulated with a photoacid generator or a photobase generator are widely used. it can. Further, a solvent-diluted type, a W / O emulsion type, and a non-sol type containing no solvent may be used. Such a photosensitive resin may be used alone or in combination of two or more.

Further, the adhesive layer may contain an additive in addition to the thermoplastic resin or the photosensitive resin. In the case of a thermoplastic resin, examples of the additive include a dispersant, a filler, a plasticizer, an antistatic agent, and the like.

When a thermoplastic resin is used, the adhesive layer 4 may be formed on the entire surface of the base material 2 as illustrated in FIG. 1, and may be patterned on the base material 2 as illustrated in FIG. 5 (a). It may be formed in. When the adhesive layer 4 is formed in a pattern on the base material 2 as shown in FIG. 5 (a), as shown in FIG. 5 (c), even if the laminated body 1 is not partially transferred. The pattern of the porous conductive layer 3 can be transferred onto the substrate 11 to be transferred.

Further, when a photosensitive resin whose adhesiveness or adhesiveness is lowered by light irradiation is used, the adhesive layer 4 is usually formed on the entire surface of the base material 2 as illustrated in FIG. 6A.
6 (a) to 6 (d) are process diagrams showing another example of the method for producing a conductive base material using the laminate of the present invention, in which the adhesive layer 4 is irradiated with light to reduce its adhesiveness or adhesiveness. This is an example of using a photosensitive resin. First, as shown in FIG. 6A, a laminate 1 in which a porous conductive layer 3 and an adhesive layer 4 are laminated in this order on a base material 2 is prepared, and light 16 is provided on the adhesive layer 4 via a photomask 15. Is irradiated in a pattern to reduce the adhesiveness or adhesiveness of the adhesive layer 4 at the light-irradiated portion to form the low adhesive portion 4b. Next, as shown in FIGS. 6 (b) to 6 (c), the adhesive layer 4 of the laminated body 1 and the substrate to be transferred 11 are arranged so as to be in contact with each other and brought into close contact with each other. Then, as shown in FIG. 6D, the base material 2 side is peeled off. Since the adhesive layer 4 has an adhesive portion 4a which is a light-irradiated portion and a low adhesive portion 4b which is a light-irradiated portion and has reduced adhesiveness or adhesiveness, the adhesive portion 4a adheres to the transfer base material 11. Although the property is high, the adhesiveness to the transfer base material 11 is low at the low adhesive portion 4b. Therefore, when the base material 2 side is peeled off, the porous conductive layer 3 and the adhesive layer 4 are peeled off together with the base material 2 in the low adhesion portion 4b, and the porous conductive layer 3 and the adhesive layer 4 are peeled off in the adhesive portion 4a by adhering to the transfer base material 11 and having porous conductivity. Layer 3 is transferred. As a result, the conductive base material 10 having the pattern of the adhesive layer 4 and the porous conductive layer 3 is obtained. Also in this case, the pattern of the porous conductive layer 3 can be transferred onto the substrate 11 to be transferred without partially transferring the laminate 1.

The thickness of the adhesive layer is not particularly limited as long as it can break the foil when the laminate of the present invention is transferred to the substrate to be transferred, such as the transfer method and the type of the substrate to be transferred. Is appropriately selected by. Specifically, the thickness of the adhesive layer is preferably in the range of 0.1 μm to 50 μm, and more preferably in the range of 1 μm to 25 μm. If the thickness of the adhesive layer is too thin, the adhesiveness to the substrate to be transferred may be insufficient. On the other hand, if it is too thick, the temperature at which the adhesive layer is heated becomes too high when the laminate of the present invention is transferred, which may cause damage to the substrate to be transferred or the like. Further, for example, when the base material to be transferred is a paper base material, some paper base materials are difficult to transfer depending on the type. In that case, the thickness of the adhesive layer is compared within the above range from the viewpoint of transferability. Thick is preferable. Further, when the laminate of the present invention is transferred to the substrate to be transferred by integral molding such as injection molding, the thickness of the adhesive layer is preferably relatively thick within the above range.

Examples of the method for forming the adhesive layer include a method in which the resin composition is applied onto the porous conductive layer and dried. As a coating method of the resin composition, it can be appropriately selected and applied from general coating methods.

Further, as illustrated in FIG. 5B, the non-adhesive layer 5 may be formed in a pattern on the adhesive layer 4. Also in this case, the pattern of the porous conductive layer 3 can be transferred onto the substrate 11 to be transferred as shown in FIG. 5C without partially transferring the laminate 1.
Examples of the material of the non-adhesive layer include a thermoplastic resin that does not melt at a temperature at which the adhesive layer melts, a thermosetting resin, a photocurable resin, and the like.
The thickness of the non-adhesive layer may be any thickness as long as the adhesive layer and the substrate to be transferred can be adhered to each other when the laminate of the present invention is transferred to the substrate to be transferred. It is appropriately selected depending on the type of transfer substrate and the like. Specifically, the thickness of the non-adhesive layer is preferably in the range of 100 nm to 3 μm.
Examples of the method for forming the non-adhesive layer include a method in which a resin composition is applied in a pattern on the adhesive layer, dried, and cured if necessary. As a coating method of the resin composition, it can be appropriately selected and applied from general coating methods.

3. 3. Base material The base material used in the present invention supports the above-mentioned porous conductive layer and adhesive layer.
The base material is not particularly limited as long as it can form the porous conductive layer. For example, an inorganic base material such as a glass substrate or a ceramic substrate, a metal base material, a resin base material, or a paper base material is used. Materials and the like can be used.
Above all, the base material is preferably a resin base material. In the present invention, since the metal particles can be sintered at a low temperature to form a porous conductive layer, the base material is less likely to be damaged, and it is not necessary to use a base material having high heat resistance. A low substrate can also be used. In particular, it is very useful in that an inexpensive general-purpose plastic resin base material such as polyethylene terephthalate can be used.

As the resin base material, a general resin base material can be used. Suitable specific examples of the resin base material include polyimide, polyamide, polyamideimide, polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyether ether ketone, polyether sulfone, polycarbonate, polyetherimide, epoxy resin, phenol resin, and glass. -Examples include epoxy resins, polyphenylene ethers, acrylic resins, polyolefins such as polyethylene and polypropylene, polycycloolefins such as polynorbornene, and resin films such as liquid crystal polymer compounds. Among them, an inexpensive general-purpose plastic resin base material such as polyethylene terephthalate is preferable.

The base material may have flexibility or rigidity, and is appropriately selected depending on the method for transferring the laminate of the present invention to the base material to be transferred and the like. Among them, the base material is preferably flexible, and for the above-mentioned reasons, it is more preferable that the base material is a flexible resin base material.

In addition, a release layer may be formed on the surface of the base material, or a release treatment may be applied. This is because the base material and the porous conductive layer or the protective layer can be easily peeled off.
Examples of the material of the release layer include a fluorine-based release agent, a silicone-based release agent, a wax-based release agent, and the like. Examples of the method for forming the release layer include a method of applying a release agent by a coating method such as dip coating, spray coating, and roll coating.
Further, examples of the mold release treatment include surface treatments such as fluorine treatment and silicone treatment.

The thickness of the base material is not particularly limited, but in the case of an inorganic base material, it is usually about 0.1 mm to 10 mm, preferably in the range of 0.5 mm to 5 mm. On the other hand, in the case of a resin base material, the thickness of the base material is usually about 1.0 μm to 1000 μm. When the thickness of the resin base material is within the above range, deformation of the base material is suppressed when the porous conductive layer is formed, which is preferable in terms of shape stability of the formed porous conductive layer, and winding. It is suitable in terms of flexibility when the cutting process is continuously performed.

4. Other Structures The laminate of the present invention may have other structures, if necessary, in addition to the above-mentioned base material, porous conductive layer and adhesive layer. For example, an antistatic layer, a heat-resistant protective layer, an abrasion-resistant layer, a slippery layer, and the like may be provided on the surface of the base material opposite to the surface on which the porous conductive layer is formed. Further, a protective layer may be formed between the base material and the porous conductive layer. The protective layer will be described below.

(Protective layer)
In the present invention, as illustrated in FIG. 7A, the protective layer 6 may be formed between the base material 2 and the porous conductive layer 3. As shown in FIG. 7B, the protective layer 6 becomes the outermost layer of the conductive base material 10 after the porous conductive layer 3 is transferred from the laminate 1 to the transfer base material 11. The porous conductive layer 3 can be protected from abrasion, light, chemicals and the like. Further, the porous conductive layer can be insulated by using the protective layer having an insulating property.

The material of the protective layer may be any material that can protect the porous conductive layer and has an insulating property, and examples thereof include an ultraviolet curable resin and an electron beam curable resin. Further, the protective layer may further contain a filler.
Moreover, you may use a protective film as a protective layer.

Examples of the method for forming the protective layer include a method in which a curable resin composition is applied onto a substrate and dried. Examples of the coating method of the curable resin composition include a gravure coating method, a roll coating method, a comma coating method, a gravure printing method, a screen printing method, and a gravure reverse roll coating method.
When a protective film is used as the protective layer, the base material and the protective film can be bonded to each other via a weak adhesive layer. As for the weak adhesive layer, it is preferable that the weak adhesive layer can be peeled off together with the base material when the base material is peeled off.

The thickness of the protective layer is preferably in the range of 0.5 μm to 30 μm, and more preferably in the range of 3 μm to 15 μm. When the thickness of the protective layer is within the above range, surface physical properties such as excellent hardness, scratch resistance, chemical resistance and stain resistance can be obtained, and further excellent moldability and shape followability can be obtained. it can.

5. Applications The laminate of the present invention can be used for producing a conductive base material as described later. For example, a printed wiring substrate, an electromagnetic wave shielding material, an antenna, a power semiconductor, a noise filter, a capacitor electrode, and electrodes for various sensors ( Touch sensors, biosensors, temperature sensors, gas sensors, optical sensors, pressure sensors, flow sensors), display electrodes, solar cell electrodes, IC cards, RFID, etc., and can be used for bonding materials and connector materials. it can.
Further, the laminate of the present invention can be used as an electromagnetic wave shield layer for preventing unauthorized reading of information recorded on a non-contact IC card, and as a conductive layer for modulating the resonance frequency. For example, it is possible to attach a porous conductive layer to a part of the card and transport it in a state where it cannot be read, and scratch and remove the adhesive layer at the time of use. Since the laminate of the present invention has a porous conductive layer, it can be easily peeled off by scratching by controlling the adhesive force of the adhesive layer.
Further, the laminate of the present invention can also be used for forming designs, designs, characters, etc. that make use of the color and luster of the porous conductive layer.

B. Method for Producing Conductive Substrate The method for producing a conductive substrate of the present invention has two embodiments. Hereinafter, each embodiment will be described separately.

1. 1. First Embodiment The method for producing a conductive base material according to this embodiment includes a preparatory step for preparing the above-mentioned laminate and a transfer step for transferring the adhesive layer and the porous conductive layer of the laminate onto the substrate to be transferred. It is a manufacturing method characterized by having.

2 (a) to 2 (c) and FIGS. 3 (a) to 3 (c) are process diagrams showing an example of a method for producing a conductive base material according to this embodiment. Note that FIGS. 2 (a) to 2 (c) and FIGS. 3 (a) to 3 (c) have been described in detail in the above "A. Laminated body", and thus the description thereof will be omitted here.

In the present embodiment, a component derived from the adhesive layer, for example, a resin contained in the adhesive layer can be allowed to enter inside the pores of the porous conductive layer, and apparently, the component derived from the porous conductive layer and the adhesive layer. By forming a mixture, it is possible to prevent thermal diffusion from occurring. Therefore, in the transfer step, heat does not easily escape, so that it is not necessary to overheat, which is advantageous for thermal transfer.

Further, in the present embodiment, as described above, the component derived from the adhesive layer can be allowed to enter the inside of the pores of the porous conductive layer, and the adhesion between the porous conductive layer and the adhesive layer can be enhanced. Therefore, in the transfer step, the adhesive layer and the porous conductive layer can be satisfactorily transferred onto the substrate to be transferred, and excellent transferability can be obtained.

Further, in the present embodiment, as described above, the resin contained in the adhesive layer can be inserted into the pores of the porous conductive layer. Therefore, in the transfer step, the resin contained in the adhesive layer is included in the porous conductive layer. It can be protected by, and the oxidation of the porous conductive layer can be suppressed. Therefore, it is possible to suppress a decrease in the conductivity of the porous conductive layer in the transfer step.

Further, in the present embodiment, since the laminate has a porous conductive layer, the foil breakability is good, and the adhesive layer and the porous conductive layer of the laminate can be satisfactorily transferred onto the substrate to be transferred. .. Further, as illustrated in FIGS. 3A to 3C, when the patterns of the adhesive layer and the porous conductive layer of the laminated body are transferred onto the substrate to be transferred, the transfer can be performed with high resolution.

Further, since the adhesive layer and the porous conductive layer are transferred onto the substrate to be transferred, a substrate to which it has been difficult to form the porous conductive layer in the past can also be used as the substrate to be transferred. Therefore, it is possible to obtain an inexpensive general-purpose plastic resin base material such as polyethylene terephthalate, or a conductive base material in which a porous conductive layer is formed on a transfer base material such as a paper base material. Furthermore, it is possible to form a porous conductive layer on the substrate to be transferred, which is a three-dimensional object. Further, the conductive base material can be easily produced only by transferring the adhesive layer and the porous conductive layer onto the base material to be transferred.

Further, in the present embodiment, since the metal particles can be sintered at a low temperature to form a porous conductive layer, it is not necessary to use a highly heat-resistant base material as the base material of the laminate, and the heat-resistant base material is used. Low substrates can also be used. In particular, an inexpensive general-purpose plastic resin base material such as polyethylene terephthalate can be used. Therefore, the manufacturing cost can be reduced.

Hereinafter, each step in the method for producing a conductive base material according to this embodiment will be described.

(1) Preparation Step The preparation step in this embodiment is a step of preparing the above-mentioned laminate.
Since the laminated body has been described in detail in "A. Laminated body" above, the description thereof is omitted here.

(2) Transfer Step The transfer step in the present embodiment is a step of transferring the adhesive layer and the porous conductive layer of the laminate onto the substrate to be transferred.

The base material to be transferred is not particularly limited as long as the porous conductive layer can be transferred via the adhesive layer, and is appropriately selected depending on the use of the conductive base material and the like. For example, a resin base material, a paper base material, a glass base material, a metal base material, and the like can be mentioned.

The method of transferring the adhesive layer and the porous conductive layer of the laminate onto the substrate to be transferred is particularly limited as long as the adhesive layer can be adhered to a predetermined position on the substrate to be transferred. Rather, it is appropriately selected depending on the material of the adhesive layer.

When a thermoplastic resin is used, examples of the thermal transfer method include a method using a heating roller or a hot stamp, a method of heat pressing, and the like.
Further, as a thermal transfer method, a method using a molding mold as illustrated in FIGS. 8A to 8D can also be mentioned. In the method for producing the conductive base material shown in FIGS. 8 (a) to 8 (d), first, the laminate 1 as shown in FIG. 8 (a) is prepared. The laminated body 1 is the same as the laminated body 1 shown in FIG. Next, as shown in FIG. 8A, the adhesive layer 4 of the laminated body 1 and the transferred base material 11 are laminated so as to be in contact with each other, and the laminated body 1 and the transferred base material 11 are attached to the base of the laminated body 1. The material 2 is arranged in the molding die having the upper die 23 and the lower die 24 so that the material 2 faces the upper die 23 and the transfer base material 11 faces the lower die 24. Subsequently, as shown in FIG. 8B, the molding die is molded while heating to form the laminate 1 and the transfer base material 11, and at the same time, the laminate 1 is thermally transferred to the transfer base material 11. .. As a result, the transfer base material 11 and the laminate 1 are integrated. Next, as shown in FIG. 8 (c), the integrated laminate 1 and the substrate to be transferred 11 are taken out from the molding die, and as shown in FIG. 8 (d), the substrate 2 is peeled off from the laminate 1. To do. As a result, the conductive base material 10 in which the adhesive layer 4 and the porous conductive layer 3 are sequentially laminated on the transfer base material 11 is obtained.

Further, when a thermoplastic resin is used, as illustrated in FIGS. 3A to 3C, when the pattern of the adhesive layer and the porous conductive layer is thermally transferred onto the substrate to be transferred, the thermal transfer method is used. For example, a method using a laser beam or a thermal head can be mentioned.

When a photosensitive resin whose adhesiveness or adhesiveness is lowered by light irradiation is used, for example, the adhesive layer of the laminated body is irradiated with light in a pattern, the laminated body and the substrate to be transferred are brought into close contact with each other, and the substrate side is pressed. A method of peeling can be mentioned. For example, a transfer method as shown in FIGS. 6 (a) to 6 (d) can be applied. In this case, the pattern of the adhesive layer and the porous conductive layer can be transferred onto the substrate to be transferred. The method for producing the conductive base material shown in FIGS. 6 (a) to 6 (d) has been described in the above "A. Laminated body", and thus the description thereof is omitted here.
Examples of the method of irradiating the adhesive layer with light in a pattern include a method using a photomask, a method of drawing light using a laser, and the like.
The light irradiated to the adhesive layer is not particularly limited as long as it is light that can reduce the adhesiveness or adhesiveness of the adhesive layer, and is appropriately selected depending on the type of the photosensitive resin. For example, ultraviolet rays, visible rays, infrared rays and the like can be used.
Examples of the method of bringing the laminate and the substrate to be transferred into close contact include a method of applying pressure, a method of applying pressure while heating, and the like.

When transferring the adhesive layer and the porous conductive layer onto the substrate to be transferred, the pattern of the adhesive layer and the porous conductive layer may be transferred onto the substrate to be transferred. It is possible to obtain a conductive base material in which a pattern of a porous conductive layer is formed on the base material to be transferred.

In the case of using a thermoplastic resin, when the pattern of the adhesive layer and the porous conductive layer is thermally transferred onto the substrate to be transferred, the method using a laser beam or a thermal head as described above may be applied. A laminated body 1 in which the adhesive layer 4 as illustrated in 5 (a) is formed in a pattern in advance may be used, and the non-adhesive layer 5 is patterned on the adhesive layer 4 as illustrated in FIG. 5 (b). The laminated body 1 formed in a shape may be used.
Further, when the pattern of the porous conductive layer is thermally transferred onto the substrate to be transferred, in addition to the above, the porous conductive layer 3 as illustrated in FIG. 4A is formed in advance in a pattern. The laminated body 1 may be used.

Further, in the case of the method using the molding die as illustrated in FIGS. 8A to 8D, when the laminate and the base material to be transferred are arranged in the molding die, the laminate and the transfer group are placed in the molding die. The material may be vacuum-sucked so that the laminate and the substrate to be transferred follow the shape of the molding die, or the laminate and the substrate to be transferred may be laminated and then heated to be molded in a softened state. It may be sandwiched between molds.

After the adhesive layer of the laminate is adhered to the substrate to be transferred, the laminate is usually physically separated from the substrate side to be porous in the region where the adhesive layer is adhered to the substrate to be transferred. The base material can be peeled off from the conductive layer.
Further, in the case of the method using the molding mold as illustrated in FIGS. 8A to 8D, in the case of the single-wafer laminated body, the molded product in which the laminated body and the base material to be transferred are integrated is obtained. After being removed from the mold, the substrate of the laminate is peeled off from the molded product. Further, in the case of a long laminate, the substrate is peeled off from the laminate when the molded product in which the laminate and the substrate to be transferred are integrated is taken out from the molding die.

2. 2. Second Embodiment The method for producing a conductive base material according to the present embodiment includes a preparatory step for preparing the above-mentioned laminate and a molten resin for a base material to be transferred in the above-mentioned laminate by arranging the laminate in a molding mold. Is injected and solidified to form the base material to be transferred, and at the same time, it has a molding and transfer step of transferring the laminate to the base material to be transferred and a peeling step of peeling the base material of the laminate. It is a manufacturing method characterized by.

The method for producing the conductive base material of the present embodiment will be described with reference to the drawings.
9 (a) to 9 (d) are process diagrams showing an example of the method for producing the conductive base material of the present embodiment. First, the laminated body 1 as shown in FIG. 9A is prepared. The laminated body 1 is the same as the laminated body 1 shown in FIG. Next, as shown in FIG. 9A, the laminate 1 is arranged in a molding die having a fixed die 21 and a movable die 22 so that the base material 2 faces the fixed die 21. Subsequently, as shown in FIG. 9B, the molding die is molded, the molten resin 11a for the substrate to be transferred is injected into the molding die, cooled and solidified to form the substrate to be transferred at the same time. , The laminate 1 is transferred to the substrate to be transferred. As a result, the base material to be transferred, which is a resin molded product, and the laminated body 1 are laminated and integrated. Next, as shown in FIG. 9 (c), the integrated laminate 1 and the substrate to be transferred 11 are taken out from the molding die, and as shown in FIG. 9 (d), the substrate 2 is peeled off from the laminate 1. To do. As a result, the conductive base material 10 in which the adhesive layer 4 and the porous conductive layer 3 are sequentially laminated on the transfer base material 11 is obtained.

In the present embodiment, a component derived from the adhesive layer, for example, a resin contained in the adhesive layer can be allowed to enter inside the pores of the porous conductive layer, and apparently, the component derived from the porous conductive layer and the adhesive layer. By forming a mixture, it is possible to prevent thermal diffusion from occurring. Therefore, in the molding and transfer steps, heat does not easily escape, so that it is not necessary to overheat, which is advantageous for transfer.

Further, in the present embodiment, as described above, the component derived from the adhesive layer can be allowed to enter the inside of the pores of the porous conductive layer, and the adhesion between the porous conductive layer and the adhesive layer can be enhanced. Therefore, in the molding and transfer steps, the adhesive layer and the porous conductive layer can be satisfactorily transferred onto the substrate to be transferred, and excellent transferability can be obtained.

Further, in the present embodiment, as described above, since the resin contained in the adhesive layer can be inserted into the pores of the porous conductive layer, the porous conductive layer is included in the adhesive layer in the molding and transfer steps. It can be protected by the resin, and the oxidation of the porous conductive layer can be suppressed. Therefore, it is possible to suppress a decrease in the conductivity of the porous conductive layer in the molding and transfer steps.

Further, in the present embodiment, since the base material to be transferred, which is a resin molded product, and the laminated body are laminated and integrated, it is possible to form a porous conductive layer on the base material to be transferred, which is a three-dimensional object.

Further, in the present embodiment, since the laminate has a porous conductive layer, the foil breakability and the resolution are good. Therefore, for example, when the laminated body 1 as shown in FIGS. 5A and 5B is used, the foil can be easily cut and the resolution can be improved.

Further, in the present embodiment, since the metal particles can be sintered at a low temperature to form a porous conductive layer, it is not necessary to use a highly heat-resistant base material as the base material of the laminate, and the heat-resistant base material is used. Low substrates can also be used. In particular, an inexpensive general-purpose plastic resin base material such as polyethylene terephthalate can be used. Therefore, the manufacturing cost can be reduced.

Hereinafter, each step in the method for producing a conductive base material according to this embodiment will be described.

(1) Preparation Step The preparation step in this embodiment is a step of preparing the above-mentioned laminate.
Since the laminated body has been described in detail in "A. Laminated body" above, the description thereof is omitted here.
In this embodiment, a thermoplastic resin is used as the material of the adhesive layer.

(2) Molding and Transfer Step In the molding and transfer step in the present embodiment, the laminate is placed in a molding mold, and the molten resin for a base material to be transferred is injected into the molding mold and solidified to form a transfer group. This is a step of transferring the laminate to the substrate to be transferred at the same time as molding the material.

When arranging the laminate in the molding die, the laminate is arranged so that the adhesive layer comes into contact with the molten resin for the substrate to be transferred when the molten resin for the substrate to be transferred is injected into the mold. At this time, a single-wafer laminate may be arranged in the molding die, or a predetermined region of the long laminate may be intermittently inserted.

When arranging the laminate in the mold, it may be heated to bring the laminate into close contact with the mold. At this time, the molding die may be heated and the laminated body may be vacuum-sucked into close contact with the molding die, or the laminated body may be heated and preformed so that the laminated body conforms to the shape of the molding die. The laminate may be adhered to the surface.
In the latter case, the heating temperature is preferably equal to or higher than the glass transition temperature of the base material of the laminate and lower than the melting temperature or the melting point, and more preferably a temperature near the glass transition temperature of the base material. The vicinity of the glass transition temperature means a range of the glass transition temperature ± 5 ° C.

As the molten resin for the substrate to be transferred, an injection-moldable thermoplastic resin or a thermosetting resin can be used. The thermosetting resin includes a two-component curable resin. The molten resin for the substrate to be transferred may be used alone or in combination of two or more.

When the molten resin for the substrate to be transferred is a thermoplastic resin, the thermoplastic resin is injected in a fluid state by heating and melting, and then cooled to solidify. When the molten resin for the substrate to be transferred is a thermosetting resin, the uncured resin composition is appropriately heated and injected in a fluid state, and then heated to solidify. As a result, the laminate is integrated with the molded base material to be transferred.
The heating temperature of the molten resin for the base material to be transferred varies depending on the type of the molten resin for the base material to be transferred, but is, for example, about 80 ° C. to 280 ° C.

When transferring the laminate to the substrate to be transferred, the pattern of the adhesive layer and the porous conductive layer may be transferred to the substrate to be transferred. It is possible to obtain a conductive base material in which a pattern of a porous conductive layer is formed on the base material to be transferred.

When the patterns of the adhesive layer and the porous conductive layer are transferred to the substrate to be transferred, a laminate 1 in which the adhesive layer 4 as illustrated in FIG. 5A is previously formed in a pattern may be used. , The laminated body 1 in which the non-adhesive layer 5 is formed in a pattern on the adhesive layer 4 as illustrated in FIG. 5B may be used.
Further, when the pattern of the porous conductive layer is transferred to the substrate to be transferred, in addition to the above, the porous conductive layer 3 as illustrated in FIG. 4A is laminated in advance in a pattern. Body 1 may be used.

After the molten resin for the base material to be transferred is solidified, a molded product in which the laminate and the molded base material to be transferred are integrated is taken out from the molding die.

(3) Peeling Step The peeling step in this embodiment is a step of peeling the base material of the laminated body.
In the case of a single-wafer laminated body, a molded product in which the laminated body and the molded base material to be transferred are integrated is taken out from the molding mold, and then the base material of the laminated body is peeled off from the molded product. Further, in the case of a long laminate, the substrate is peeled off from the laminate when the molded product in which the laminate and the molded substrate to be transferred are integrated is taken out from the molding die.
As a result, a conductive base material in which an adhesive layer and a porous conductive layer are sequentially laminated on a base material to be transferred, which is a resin molded body, can be obtained.

C. Manufacturing Method of Electronic Device The manufacturing method of the electronic device of the present invention is a manufacturing method characterized by having a conductive base material manufacturing step of manufacturing a conductive base material by the above-mentioned manufacturing method of a conductive base material. ..

In the present invention, since the conductive base material is produced by the above-mentioned method for producing a conductive base material, a porous conductive layer having good conductivity can be formed. Further, for example, when forming a pattern of a porous conductive layer, a high-resolution pattern can be formed.
Further, in the present invention, since the conductive base material is produced by the above-mentioned method for producing the conductive base material, the production cost can be reduced.

Hereinafter, the steps in the method for manufacturing the electronic device of this embodiment will be described.

1. 1. Conductive base material manufacturing step The conductive base material manufacturing step in the present invention is a step of manufacturing a conductive base material by the above-mentioned method for manufacturing a conductive base material.
Since the method for producing the conductive base material has been described in detail in "B. Method for producing the conductive base material" above, the description thereof is omitted here.

2. 2. Electronic device Examples of the electronic device in the present invention include a printed wiring board, an electromagnetic wave shielding material, an antenna, a power semiconductor, a noise filter, a capacitor electrode, and electrodes for various sensors (touch sensor, biosensor, temperature sensor, gas sensor, optical sensor). , Pressure sensor, flow sensor), display electrodes, solar cell electrodes, IC cards, RFID, bonding materials, connector materials, and the like.
Further, when the electronic device of the present invention is, for example, a non-contact type IC card, the porous conductive layer modulates an electromagnetic wave shield layer and a resonance frequency for preventing unauthorized reading of information recorded on the non-contact type IC card. It can be used as a conductive layer for making it. In this case, for example, the card can be temporarily provided with a porous conductive layer, and the adhesive layer can be scratched and removed later. Since the electronic device of the present invention has a porous conductive layer, it can be easily peeled off by scratch by controlling the adhesive force of the adhesive layer.

The method for manufacturing an electronic device of the present invention may include, if necessary, other steps in addition to the conductive base material manufacturing step. Other steps are appropriately selected depending on the electronic device.

The present invention is not limited to the above embodiment. The above embodiment is an example, and any one having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same action and effect is the present invention. It is included in the technical scope of the invention.

Examples and comparative examples are shown below, and the present invention will be described in more detail.

[Synthesis Example 1: Synthesis of Copper Particles]
In a 200 ml three-necked flask, 10.0 g of copper hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.), 34.5 g of decanoic acid (Lunac 10-98 manufactured by Kao), and 18.5 g of propylene glycol monomethyl ether (PGME) were weighed. .. The mixture was heated to 100 ° C. with stirring and the temperature was maintained for 20 minutes. Then, 41.3 g of 3-ethoxypropylamine (manufactured by Koei Chemical Industry Co., Ltd.) was added, and the mixture was heated at 100 ° C. for 10 minutes and stirred. This mixed solution was cooled to 10 ° C. using an ice bath, and then a solution prepared by dissolving 10.0 g of hydrazine monohydrate in 18.5 g of PGME (manufactured by Kanto Chemical Co., Inc.) was added in the ice bath for 10 minutes. Stirred. Then, the reaction solution was heated to 100 ° C. and the temperature was maintained for 10 minutes. After cooling to 30 ° C., 66 g of hexane was added. After centrifugation, the supernatant was removed. The precipitate was washed with hexane to give copper particles.
When the obtained copper particles were observed with a transmission electron microscope (TEM), the average primary particle size was 65 nm.

[Preparation Example 1: Preparation of Copper Particle Dispersion 1]
40 parts by mass of copper particles obtained in Synthesis Example 1, 4 parts by mass of Solsparse 41000 (manufactured by Lubrizol) and 56 parts by mass of propylene glycol monomethyl ether (PGME) were mixed as a polymer dispersant, and a paint shaker (manufactured by Asada Iron Works) was mixed. As a preliminary dispersion, 2 mm zirconia beads were used for 1 hour, and as a main dispersion, 0.1 mm zirconia beads were used for 2 hours to obtain a copper particle dispersion 1.

[Production Example 1: Production of Conductive Film A]
A copper particle dispersion 1 is applied to a PET film (trade name: Cosmo Shine A4100, manufactured by Toyobo, 100 μm in thickness) using Miyabar # 4, dried at 80 ° C. for 3 minutes in a warm air dryer, and has a red copper luster. Got Then, while introducing hydrogen gas at an introduction pressure of 20 Pa, a porous conductive layer was formed by firing at a microwave output of 450 W for 240 seconds using a microwave surface wave plasma processing device (MSP-1500, manufactured by Microelectronics Co., Ltd.). Conductive film to have Conductive film A was obtained.

[Manufacturing Example 2: Production of Conductive Film B]
A conductive film B having a porous conductive layer was obtained by firing at a microwave output of 450 W for 120 seconds by the same production method as that of the conductive film A except that the film was changed to a PET film (thickness 5 μm).

[Manufacturing Example 3: Production of Conductive Film C]
Copper was formed on a PET film (trade name: Cosmoshine A4100, manufactured by Toyobo Co., Ltd., film thickness 100 μm) by a sputtering method to obtain a conductive film C having a conductive layer.

[Evaluation]
(Measurement of sheet resistance of conductive layer)
The conductivity of the conductive layer was evaluated by measuring the sheet resistance value by a 4-probe method using a surface resistance meter (“Loresta GP” manufactured by Dia Instruments, PSP type probe). The sheet resistance values of the porous conductive layers of the conductive films A and B were both 0.20 Ω / □, and the sheet resistance values of the conductive layer of the conductive film C were 0.075 Ω / □.

(Measurement of film thickness of conductive layer)
The film thickness of the conductive layer was evaluated as follows. Regarding the produced conductive film, carbon is sequentially laminated on the upper part of the conductive layer as a protective layer by a vacuum deposition method, platinum is sequentially laminated by a sputtering method, and then tungsten is laminated using FIB (focused ion beam, FB-2100 manufactured by Hitachi High-Tech). Later, a cross section of the conductive layer was prepared. Then, using SEM (Hitachi High-Tech S-4800), the cross section of the conductive layer was observed with the substrate tilted by 45 °, and the film thickness was measured from the SEM image. The film thickness was measured at 10 points in the SEM image measured at a magnification of 30 k to 40 k, the inclination was corrected, and the average value was taken as the film thickness. The film thickness of the conductive layer was 400 nm in all of the conductive films A, B, and C. From this result, it was found that the volume resistance values of the conductive films A and B were 8 μΩ · cm, and the volume resistance values of the conductive films C were 3 μΩ · cm.

(Measurement of porosity of conductive layer)
The porosity of the conductive layer was measured as follows. In the SEM image obtained in the above film thickness measurement, the area of the pores and the area of the conductive layer were calculated, and the porosity in the cross section was obtained by dividing the area of the holes by the area of the conductive layer. The porosity of the porous conductive layer of the conductive film A was 35%, and the porosity of the porous conductive layer of the conductive film B was 25%. There were no holes in the conductive layer of the conductive film C.

[Example 1]
(Formation of adhesive layer)
A coating solution was prepared by adding 30% by mass of methyl isobutyl ketone (MIBK) to TM-R850 (LV-NT) K3 manufactured by Dainichiseika Co., Ltd., which is an adhesive, and stirring sufficiently. This coating liquid was applied onto the porous conductive layer of the conductive film A with an applicator 10 mil, and dried at 90 ° C. for 1 minute with a warm air dryer.

(Transfer)
Next, a laminated film C001 (Sumitomo Chemical Co., Ltd., film thickness 125 μm) made of polycarbonate (hereinafter abbreviated as PC) and polymethylmethacrylate (hereinafter abbreviated as PMMA) was used as the transfer base material on the PC surface of the transfer base material. The adhesive-coated surfaces of the above-mentioned conductive film A were overlapped, and heat laminating treatment was performed using a multi-laminator GL835PRO manufactured by Nippon GBC at a temperature of 130 ° C., a GAP of 1 mm or less, and a transport speed of 0.3 m / min. Then, the PET film was peeled off.
The porous conductive layer was 100% transferred to the substrate to be transferred, and the sheet resistance value after transfer was 0.22 Ω / □.

[Example 2]
In the formation of the adhesive layer, WASHIN CHEMICAL PLUS COAT PGC10 was applied as an adhesive on the porous conductive layer of the conductive film A with an applicator 10 mil, dried at 90 ° C. for 1 minute in a warm air dryer, and transferred. In the same manner as in Example 1, the adhesive layer was formed and transferred except that the temperature was set to 130 ° C.
The porous conductive layer was 100% transferred to the substrate to be transferred, and the sheet resistance value after transfer was 0.20 Ω / □.

[Example 3]
In the formation of the adhesive layer, Mitsui Chemicals' Chemipearl S300 was applied as an adhesive on the porous conductive layer of the conductive film A with Miyabar # 8, dried at 70 ° C. for 3 minutes in a warm air dryer, and transferred. In the above, a commercially available copy paper was used as the base material to be transferred, and the adhesive layer was formed and transferred in the same manner as in Example 1 except that the temperature was set to 100 ° C.
The porous conductive layer was 100% transferred to the substrate to be transferred, and the sheet resistance value after transfer was 0.20 Ω / □.

[Example 4]
In the formation of the adhesive layer, Mitsui Chemicals' Chemipearl EV210 was applied as an adhesive on the porous conductive layer of the conductive film A with Miyabar # 16 and dried at 90 ° C. for 3 minutes in a warm air dryer, and transfer. In the same manner as in Example 1, the adhesive layer was formed and transferred except that the temperature was set to 150 ° C.
The porous conductive layer was 100% transferred to the substrate to be transferred, and the sheet resistance value after transfer was 0.20 Ω / □.

[Example 5]
In the formation of the adhesive layer, Bonron XPS-001 manufactured by Mitsui Chemicals Co., Ltd. was applied as an adhesive on the porous conductive layer of the conductive film A with Miyaber # 16 and dried at 90 ° C. for 3 minutes in a warm air dryer. In the transfer, a glossy paper was used as the base material to be transferred, and the adhesive layer was formed and transferred in the same manner as in Example 1 except that the temperature was set to 130 ° C.
The porous conductive layer was 100% transferred to the substrate to be transferred, and the sheet resistance value after transfer was 0.21 Ω / □.

[Example 6]
In the formation of the adhesive layer, Bonron XPS-003 manufactured by Mitsui Chemicals Co., Ltd. was applied as an adhesive on the porous conductive layer of the conductive film A with Miyaber # 16 and dried at 90 ° C. for 3 minutes in a warm air dryer. In the transfer, a glossy paper was used as the base material to be transferred, and the adhesive layer was formed and transferred in the same manner as in Example 1 except that the temperature was set to 150 ° C.
The porous conductive layer was 100% transferred to the substrate to be transferred, and the sheet resistance value after transfer was 0.20 Ω / □.

[Example 7]
(Formation of adhesive layer)
BCD # 700 clear manufactured by DNP Fine Chemicals was applied as an adhesive on the porous conductive layer of the conductive film B with Miyaver # 4, and dried at 90 ° C. for 3 minutes in a warm air dryer.

(Transfer)
When the conductive film B on which the adhesive layer was formed was set as a transfer ribbon on a thermal head printer (Zebra140Xi4) and a printing test was performed using gloss coated paper as the base material to be transferred, a wiring having a line width of 127 μm and a total length of 10 cm was found. It was formed and the continuity could be confirmed by the tester.

[Comparative Example 1]
When the transfer was performed in the same manner as in Example 1 except that the conductive film C was used instead of the conductive film A, no transfer was possible.

[Comparative Example 2]
When the transfer was performed in the same manner as in Example 2 except that the conductive film C was used instead of the conductive film A, no transfer was possible.

[Comparative Example 3]
When the transfer was performed in the same manner as in Example 3 except that the conductive film C was used instead of the conductive film A, no transfer was possible.

[Comparative Example 4]
When the transfer was performed in the same manner as in Example 4 except that the conductive film C was used instead of the conductive film A, no transfer was possible.

[Comparative Example 5]
When the transfer was performed in the same manner as in Example 5 except that the conductive film C was used instead of the conductive film A, no transfer was possible.

[Comparative Example 6]
When the transfer was performed in the same manner as in Example 6 except that the conductive film C was used instead of the conductive film A, no transfer was possible.

[Manufacturing Example 4: Production of Conductive Film D]
Nano Ag ink (trade name: MDot CF107 manufactured by Mitsuboshi Belt) is diluted 40% with pentandiol, then applied to PET film (trade name: Cosmoshine A4100, manufactured by Toyobo, film thickness 100 μm) using Miyabar # 4, and warm air is used. It was dried and fired at 120 ° C. for 30 minutes in a dryer to obtain a conductive film D having a silver luster and a porous conductive layer.
The film thickness of the porous conductive layer of the conductive film D was 380 nm, the sheet resistance value was 0.20 Ω / □, and the porosity was 30%.

[Example 8]
In the formation of the adhesive layer, Mitsui Chemicals' Chemipearl S300 was applied as an adhesive on the porous conductive layer of the conductive film D with Miyabar # 4, dried at 90 ° C. for 3 minutes in a warm air dryer, and transferred. The adhesive layer was formed and transferred in the same manner as in Example 1 except that gloss-coated paper was used as the substrate to be transferred and the temperature was set to 130 ° C.
The porous conductive layer was 100% transferred to the substrate to be transferred, and the sheet resistance value after transfer was 0.20 Ω / □.

[Example 9]
(Formation of adhesive layer)
A coating solution was prepared by additionally diluting TM-R850 (LV-NT) K3 manufactured by Dainichiseika Co., Ltd., which is an adhesive, with methyl isobutyl ketone (MIBK) equivalent to 30% by mass. This coating liquid was applied onto the porous conductive layer of the conductive film A with an applicator 10 mil, and dried at 90 ° C. for 1 minute with a warm air dryer.

(Transfer)
After the conductive film A on which the adhesive layer was formed was set in the mold of the in-mold molding machine, a mixed resin composed of PC and ABS was melted and poured into the adhesive-coated surface. After cooling, the molded product was taken out and the PET film was peeled off.
The porous conductive layer was 100% transferred to a resin layer made of a mixed resin of PC and ABS, and the sheet resistance value after the transfer was 0.22Ω / □.

1 ... Laminate 2 ... Base material 3 ... Porous conductive layer 4 ... Adhesive layer 6 ... Protective layer 10 ... Conductive base material 11 ... Transfer base material

Claims (7)

With the base material
The porous conductive layer formed on the base material and
It has an adhesive layer formed on the porous conductive layer and has.
The porous conductive layer is a sintered body of metal nanoparticles.
A laminate in which the porous conductive layer is formed on the entire surface of the base material. The laminate according to claim 1, wherein the base material is a resin base material. The laminate according to claim 1 or 2, wherein a protective layer is formed between the base material and the porous conductive layer. The preparatory step for preparing the laminate according to any one of claims 1 to 3,
A method for producing a conductive base material, which comprises a transfer step of transferring an adhesive layer and a porous conductive layer of the laminate onto a base material to be transferred. The method for producing a conductive base material according to claim 4, wherein in the transfer step, a pattern of an adhesive layer and a porous conductive layer of the laminate is transferred onto the base material to be transferred. The preparatory step for preparing the laminate according to any one of claims 1 to 3,
The laminate is placed in a molding die, and a molten resin for a substrate to be transferred is injected into the mold and solidified to form the substrate to be transferred, and at the same time, the laminate is transferred to the substrate to be transferred. Molding and transfer process and
A method for producing a conductive base material, which comprises a peeling step of peeling the base material of the laminated body. A method for manufacturing an electronic device, which comprises a conductive base material manufacturing step for manufacturing a conductive base material by the method for manufacturing a conductive base material according to any one of claims 4 to 6.

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