JP6939150B2 - Method for manufacturing conductive composition and conductor film - Google Patents

Description

The present invention relates to a conductive composition that exhibits excellent conductivity.

In recent years, conductive paints and conductive adhesives using a conductive resin composition have been increasing from the viewpoints of reducing the weight of products, considering the environment, and suppressing manufacturing costs (Patent Document 1). In such applications, high conductivity is required, and metals such as silver and copper are often used as the conductive filler. However, in applications where long-term reliability is required, various resistances, especially corrosion resistance, are required, and in such applications, metals such as silver and copper cannot be used, so conductive carbon-based fillers are often used. Will be done.
As a conductive composition using a conductive carbon-based filler, a low resistance conductive composition has been studied using graphite, carbon nanotubes, or the like (Patent Documents 2 and 3). However, it is difficult to develop high conductivity as compared with metal fillers, and carbon-based fillers have a lighter specific density than metals and carbon in the composition for exhibiting high conductivity. If the filling amount of the system filler is large, there is a problem that printing coating by screen printing or the like becomes difficult.

Japanese Patent Application No. 2014-551472 Japanese Patent Application No. 2001-60413 Japanese Patent Application No. 2002-20515

An object of the present invention is to provide a composition which has good corrosion resistance, exhibits excellent conductivity, and is also suitable for printing and coating.

As a result of diligent studies to solve the above problems, the present inventors have found that the conductive composition shown below can be printed while exhibiting high conductivity, and have completed the present invention.

That is, the present invention is a conductive composition containing a binder resin (A), a conductivity-imparting agent (B), and an organic solvent (C), and the binder resin (A) is a polyolefin resin (A-). Selected from the group consisting of 1) and the styrene-based elastomer resin (A-2), the conductivity-imparting agent (B) contains expanded graphite (B1), and the average particle size of the expanded graphite is 10 μm or more and 200 μm or less. The present invention relates to a conductive composition, wherein the content of the conductivity-imparting agent (B) is 40% by mass or more and 90% by mass or less in 100% by mass of the solid content of the composition.

The present invention also relates to the above-mentioned conductive composition, wherein the expanded graphite (B1) has an average particle size of 25 μm or more and 150 μm or less.

The present invention also relates to the above-mentioned conductive composition, wherein the volume resistance value of the formed coating film is 10 ^-3 Ωcm or more and ^{less than 10 -1 Ωcm.}

The present invention further relates to the above-mentioned conductive composition, wherein the conductivity-imparting agent (B) contains carbon black (B2).

Further, in the present invention, the organic solvent (C) contains an organic solvent (C1) having a viscosity of 30 mPa · s or more and 75,000 mPa · s or less at 25 ° C., and the content of the organic solvent (C1) is organic. The present invention relates to the above-mentioned conductive composition, which is characterized in that the content of the solvent (C) is 10% by mass or more in 100% by mass.

The present invention also relates to a method for producing a conductor film, which comprises applying the above-mentioned conductive composition to a base material and then heat-pressing the conductor film obtained by drying.

The present invention also relates to the above-mentioned method for producing a conductor film, wherein the volume resistance value of the conductor film is 10 ^-4 Ωcm or more and ^{less than 10 -2 Ω cm.}

The present invention also relates to a method for producing a conductive film in which the conductive composition is patterned by screen printing to form a conductor wiring.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a composition which has good corrosion resistance, exhibits high conductivity, and is also suitable for printing and coating.

Hereinafter, embodiments of the present invention will be described.
The conductive composition of the present invention (hereinafter, may be referred to as "composition") is characterized by containing a binder resin (A), a conductivity-imparting agent (B), and an organic solvent (C).

<Binder resin (A)>
The binder resin used in the present invention is selected from the group consisting of the polyolefin resin (A-1) and the styrene elastomer resin (A-2). By using the above resin, the volume resistance value, the adhesion to the base material, and the durability are improved. The volume resistance value is a good result because the resin component in the hot press easily flows.

[Polyolefin resin (A-1)]
The polyolefin resin (A-1) used in the present invention includes random polymers or block polymers obtained by anionic polymerization, cationic polymerization, coordination polymerization, etc. of olefinic monomers, and acid anhydride modified products and amine modified products thereof. , Chlorinated product, graft modified product and the like.

Examples of the olefin-based monomer used in the synthesis of the polyolefin resin include compounds having one or more ethylenic carbon-carbon double bonds in the molecule (excluding (meth) acrylic compounds, vinyl ether compounds, vinyl ester compounds, and acrylonitrile). Anyway, α-olefin monomer, conjugated diene monomer, isobutene and the like can be mentioned. Examples of the α-olefin monomer include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene or 3-methyl-1-. Examples thereof include terminal olefin compounds having 3 to 12 carbon atoms such as pentene. Examples of the conjugated diene monomer include 1,3-butadiene, isoprene, β-farnesene and the like. These olefin-based monomers may be polymerized using only one type, or two or more types may be used in combination.

Further, the polyolefin resin (A-1) is obtained by copolymerizing a monomer other than the olefin monomer (excluding styrene) with the olefin monomer essential as long as the characteristics of the present invention are not lost. May be good. Examples of the monomer other than the above-mentioned olefin-based monomer used for copolymerization include (meth) acrylic compounds such as ethyl acrylate, methyl methacrylate and glycidyl methacrylate, acrylonitrile, vinyl acetate, maleic acid anhydride and the like.

Examples of commercially available products of such polyolefin resin (A-1) include Toughmer BL2491, Toughmer BL3450 (poly1-butene resin manufactured by Mitsui Chemicals), Toughmer XM-7080, and Toughmer XM-5090 (1-butene propylene manufactured by Mitsui Chemicals). Copolymer resin), Toughmer MA-8510, Toughmer MA7020 (Mitsui Chemicals' acid anhydride-modified polyolefin resin), Auroralen 100S, Auroralen 250S (Nippon Paper Co., Ltd., acid anhydride-modified polyolefin resin), Supercron 814HS, Super Clon 390S (manufactured by Nippon Paper Co., Ltd., chlorinated polyolefin resin), Modiper A3400 (manufactured by Nichiyu Co., Ltd., modified side chain acrylonitrile graft of polypropylene), Modiper A4300 (manufactured by Nichiyu Co., Ltd., side of ethylene-glycidyl methacrylate copolymer) Chain methyl methacrylate / butyl acrylate graft modified product) and the like. Only one of these may be used, or two or more thereof may be used in combination.

[Styrene elastomer resin (A-2)]
The styrene elastomer resin (A-2) used in the present invention may be a random polymer or a block polymer obtained by anionic polymerization or cationic polymerization of the olefin monomer and styrene, and may be, for example, SBS (styrene-butadiene-styrene). Block polymer), SIS (styrene-isoprene-styrene block polymer), SEBS (styrene-ethylenebutylene-styrene block polymer), SBBS (styrene-1-butene butylene-styrene block polymer), SEPS (styrene-ethylenepropylene-styrene) Block polymers), SIBS (styrene-isobutene-styrene block polymers), and their acid anhydride modified and amine modified products.

Commercially available products of such a styrene elastomer resin (A-2) include, for example, Toughprene A, Asaprene T-411 (manufactured by Asahi Kasei Co., Ltd., SBS resin), JSRSIS5002, JSRSIS5506 (manufactured by JSR, SIS resin), Toughtech H1401 and Toughtech. H1517 (Asahi Kasei Co., Ltd., SEBS resin), Septon S2005 and Septon S2104 (Kuraray Co., Ltd., SEPS resin), Tough Tech M1913 and Tough Tech M1924 (Asahi Kasei Co., Ltd., maleic acid anhydride-modified SEBS resin), Tough Tech MP10 (Asahi Kasei Co., Ltd., Amine-modified SEBS resin), S.A. O. E1605 and S.A. O. Examples thereof include E1606 (Asahi Kasei Corporation, hydrogenated styrene-based thermoplastic elastomer resin) SIBSTAR072T and SIBSTAR102T (Kaneka Corporation, SIBS resin). Only one of these may be used, or two or more thereof may be used in combination.

The polyolefin resin (A-1) or the styrene elastomer resin (A-2) may be used in combination with another binder resin. Binder resins that can be used in combination include polyurethane-based, acrylonitrile-based, acrylic-based, butadiene-based, polyamide-based, polyvinyl butyral-based, polyolefin-based, polyester-based, polystyrene-based, EVA-based, polyvinylidene fluoride-based, and silicon-based resins. It can contain one or more species selected from the group consisting of. It is not limited to these resins.
The binder resin can also be cured (crosslinked) with a curing agent after the conductive composition is applied to the substrate.

<Conductivity imparting agent (B)>
The conductive composition of the present invention is characterized by containing expanded graphite (B1) as a conductivity-imparting agent.
(Expanded graphite (B1))
The expanded graphite used in the present invention is expanded graphite obtained by chemically treating scaly graphite (also referred to as expansive graphite; Expandable Graphite), which is heat-treated to expand and then refined. It also includes expanded graphite powder obtained by crushing a graphite sheet that has been rolled before miniaturization.
The expanded graphite can be appropriately selected from conventionally known expanded graphite. Commercially available expanded graphite may be used. Examples of commercially available expanded graphite include EC1500, EC1000, EC500, EC300, EC100, and EC50 manufactured by Ito Graphite Industry Co., Ltd. (all are trade names).
The shape of the expanded graphite is not particularly limited. For example, flaky expanded graphite processed into flakes can be mentioned.
Expanded graphite can exhibit high conductivity with a small amount of content as compared with other graphites. For example, it tends to exhibit higher conductivity in a smaller amount than general scaly graphite.

The average particle size of the expanded graphite is 10 μm to 200 μm, more preferably 25 to 150 μm. It is preferably 10 μm or more from the viewpoint of improving the conductivity of the conductive film to be formed, and 200 μm or less from the viewpoint of the coatability of the conductive composition and the adhesion of the formed conductive film to the substrate. preferable.
Further, it is preferable that the difference in particle size between D10 (μm) and D90 (μm) is 60 μm or more.
The "average particle size" in the present invention means the particle size at an integrated value of 50% in the particle size distribution obtained by the laser diffraction / scattering method. D10 (μm) and D90 (μm) mean particle sizes of integrated values of 10% and 90%.
The measurement shall be performed under the following conditions.
Measuring equipment: Microtrack MT3300EXII (Microtrack Bell Co., Ltd.)
Measurement sample Preparation method: After adding 0.63 g of graphite and 11.87 g of toluene to a glass bottle with a lid (M-70), planetary stirring (Sinky Co., Ltd .: Awatori Rentaro, stirring time: 3 minutes) is performed to disperse. Prepare a liquid and carry out the measurement.

When the solid content of the conductive composition is 100% by mass, the content of the conductivity-imparting agent (B1) is 40% by mass to 90% by mass, more preferably 50% by mass to 85% by mass. .. From the viewpoint of improving the conductivity of the conductive film formed, 40% by mass or more is preferable, and from the viewpoint of the coatability of the conductive composition and the adhesion of the conductive film to be formed to the substrate, 90% by mass or less is preferable.

(Carbon black (B2))
In the present invention, carbon black can be further used as the conductivity-imparting agent. By using expanded graphite and carbon black in combination, carbon black plays a role of connecting the conductive paths of expanded graphite, and tends to exhibit high conductivity without going through a hot pressing process.
As the carbon black, conventionally known conductive carbons such as acetylene black, ketjen black, and furnest black can be used.
The mass composition ratio of expanded graphite (B1) and carbon black (B2) is 60 to 90% by mass for expanded graphite and 10 for carbon black when the total mass of expanded graphite and carbon black is 100% by mass. -40% by mass is preferable. The carbon black (B2) is preferably 40% by mass or less from the viewpoint of utilizing the high conductivity derived from the expanded graphite, and the carbon black (B2) is 10% by mass or more from the viewpoint of connecting the conductive paths between the expanded graphites. Is preferable.

(Other conductivity-imparting agents)
Examples of other conductivity-imparting agents include graphite other than expanded graphite, carbon nanotubes, graphene, graphene oxide, and coke. However, this does not apply as long as the physical properties are not impaired. In addition, one kind or two or more kinds can be used together.

<Organic solvent (C)>
Organic solvents include alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol methyl ether and diethylene glycol methyl ether, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether and the like. Suitable depending on the composition of the conductive composition from among ethers, hydrocarbons such as hexane, heptane and octane, aromatics such as benzene, toluene, xylene and cumene, and esters such as ethyl acetate and butyl acetate. Can be used. Further, two or more kinds of solvents may be used.
When a printing coating method that requires a certain level of viscosity or higher in the ink composition such as screen printing is adopted, the viscosity at 25 ° C. is 30 mPa · s to 75,000 mPa · s organic solvent (C1) organic. The solvent (C) preferably contains 10% by mass or more in 100% by mass. From the viewpoint of improving the conductivity of the conductive film formed, it is desirable to reduce the amount of the binder (A), but if the amount of the binder (A) is small, the dispersibility of the conductivity-imparting agent (B) decreases. The coatability of the conductive composition is also reduced. Use an organic solvent of 30 mPa · s or more at 25 ° C. from the viewpoint of improving the dispersibility of the conductivity-imparting agent (B) and functioning as a "pseudo-binder" that makes the conductive composition viscous suitable for coating. Is preferable. On the other hand, from the viewpoint of improving the dispersibility of the conductivity-imparting agent (B), it is preferable that the viscosity is not too high, and specifically, it is preferable to use an organic solvent of 75,000 mPa · s or less at 25 ° C.

Examples of such an organic solvent (C1) include terpineol, dihydroterpineol, 2,4-diethyl-1,5-pentanediol, 1,3-butylene glycol, and isobornylcyclohexanol. Two or more kinds of high-viscosity solvents shown here may be used.
Further, the organic solvent (C1) can be used in combination with a low-viscosity solvent such as methyl ethyl ketone, toluene, and isopropyl alcohol, which has a viscosity of less than 30 mPa · s at 25 ° C.

The viscosity shown here means a numerical value obtained by the following measuring method.
The measurement was performed using a rheometer (MCR302) manufactured by Anton Pearl Japan. As a measurement method, the measurement sample is measured under the following conditions after installation, and the numerical value 60 seconds after the start of shearing is read.
Measuring jig: Cone plate CP25-2 (If this jig cannot measure, use cone plate CP50-1)
Rotation speed: 1000 (1 / sec)
Plate temperature: 25 ° C

<Other ingredients>
The conductive composition of the present invention contains, if necessary, an ultraviolet absorber, an ultraviolet stabilizer, a radical catching agent, a filler, a thixotropy-imparting agent, an antistatic agent, and an antioxidant, as long as the effects of the present invention are not impaired. Agents, antistatic agents, flame retardants, thermal conductivity improvers, plasticizers, anti-sag agents, antifouling agents, preservatives, bactericides, defoamers, leveling agents, anti-blocking agents, hardeners, thickeners, Various additives such as a pigment dispersant and a silane coupling agent may be added.
<Hardener>
The curing agent is not particularly limited as long as it reacts with the functional group of the binder resin, and examples thereof include a polyfunctional epoxy compound, a polyfunctional aziridine compound, and a polyfunctional isosine compound.

<Conductive composition>
The conductive composition of the present invention can be produced by using the above-mentioned binder resin, expanded graphite, and organic solvent as essential components, and further adding other components as necessary and uniformly dispersing them. ..
The dispersion method is carried out by dissolving the binder resin in a solvent, adding a conductive filler, and then stirring the planet, using a three-roll, two-roll, scandex, or bead mill. The solvent used is not particularly limited as long as it dissolves the binder resin. A dispersion method other than the above may be used as long as the physical properties are not deteriorated.
However, when a curing agent is used, the curing agent shall be added after the conductive composition is dispersed. After adding the curing agent, the mixture is appropriately mixed by planetary stirring, a mix rotor, a disper, or the like. The mixing method is not particularly limited.

<Base material>
Examples of the base material include PET (polyethylene terephthalate), PEN (polyethylene naphthalate), polyimide, polyvinyl chloride, polyamide, OPP (stretched polypropylene), CPP (unstretched polypropylene) and the like, but are not particularly limited.

<Conductor film>
The conductor film of the present invention is formed by applying a conductive composition and drying it.
The method of applying the conductive composition to the base material is shown below. As the coating method, a known method may be used, and the inkjet method, spray method, spin coating method, dip method, roll coating method, blade coating method, doctor roll method, doctor blade method, curtain coating method, slit coating method, Examples thereof include a screen printing method and a reverse printing method, but the method is not particularly limited.
The drying conditions are not particularly limited, and examples thereof include hot air drying, infrared rays, and decompression methods. In the case of hot air drying, it is usually dried at about 60 to 200 ° C., although it depends on the film thickness and the selected organic solvent. Further, when a plastic film such as PET or PEN is used as the base material, the base material may be deformed by heat, so 60 to 150 ° C. is more preferable.
When the conductive film is used as the conductor wiring, the film thickness after coating is preferably 50 to 1000 μm from the viewpoint of conductivity and handleability.

In order to further reduce the resistance of the conductive film after coating, it is preferable to perform a hot press treatment. The volume resistance value after the hot press treatment is preferably 10-4 Ωcm or more and less than 10-2 Ωcm.

<Heat pressing method>
The heat pressing method may be any method as long as it does not damage the conductive film and the substrate. For example, a roll pressurization method, a press pressurization method and the like can be mentioned. The pressure, temperature, press time, and roll speed are not particularly limited as long as they do not impair the physical characteristics of the present invention. Regarding the temperature, when a film base material is used, it may be deformed by heat, so 50 ° C. to 200 ° C. is preferable.
When the composition is used with conductor wiring, the film thickness after hot pressing is preferably 30 to 200 μm.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples do not limit the scope of rights of the present invention at all. In the examples, "parts" and "%" represent "parts by mass" and "% by mass", respectively, Mw means mass average molecular weight, and Tg means glass transition temperature.

[Binder resin (A)]
<For examples>
(A-1-a) Auroralen 250S: manufactured by Nippon Paper Industries, Inc., acid anhydride-modified polyolefin resin, solid content ratio 100%
(A-1-b) Supercron 390S: Nippon Paper Industries, Ltd., chlorinated polyolefin resin, 100% solid content
(A-1-c) Modiper A3400: Made by NOF Corporation, side chain acrylonitrile graft modified product of polypropylene, solid content 100%
(A-1-d) Modiper A4300: NOF Corporation, side chain methyl methacrylate / butyl acrylate graft modified product of ethylene-glycidyl methacrylate copolymer, solid content 100%

(A-2-a) Tough Tech H1041: Hydrogenated styrene-based thermoplastic elastomer resin manufactured by Asahi Kasei Corporation, 100% solid content
(A-2-b) Tough Tech M1913: Asahi Kasei Co., Ltd., maleic acid anhydride-modified hydrogenated styrene-based thermoplastic elastomer resin (A-2-c) Tough Tech MP10: Asahi Kasei Co., Ltd., amine-modified hydrogenated styrene-based thermoplastic elastomer resin Resin, solid content 100%
(A-2-d) SIBSTAR102T: Kaneka Corporation, styrene-isobutylene block copolymer resin, 100% solid content

<For comparative example>
(A-3-a) N-730A: DIC phenolovolac type epoxy resin, 100% solid content
(A-3-b) Nipol AR42W: Acrylic rubber polymer manufactured by Zeon Corporation, 100% solid content
(A-3-c) Eslek BM-2: Polyvinyl butyral manufactured by Sekisui Chemical Co., Ltd., 100% solid content
(A-3-d) Shonor BRG-556: Made of Aica SDK Phenol, novolac type phenol resin, 100% solid content
(A-3-e) JP03: Polyvinyl alcohol made by Japan Vam & Poval, 100% solid content
(A-3-f) K-30: Polyvinylpyrrolidone manufactured by Nippon Shokubai, 100% solid content

<Adjustment of binder resin solution>
As shown in Table 1, the binder resins used in Examples and Comparative Examples were adjusted to a solution having a solid content of 20% using the solvents 1 to 5 shown below. The composition ratio of the mixed solvent is described as a mass ratio.
1: Toluene / MEK / IPA (1/1/1)
2: Terpineol 3: Terpineol / isobornylcyclohexanol (7/3)
4: Diethylene glycol monoethyl ether acetate (hereinafter, EDGAC)
5: Water / EtOH (1/1)

<Example 1>
A conductivity-imparting agent and an organic solvent were added to the solution of the binder resin A-1-a-1 in the types and blending amounts shown in Table 2, and finally, glass beads (3 mm) having the same mass as the solution were added. Dispersion was carried out by Scandex to remove beads, and then a conductive composition was obtained. The composition was applied to a PET film with an applicator 12 mil and then dried at 80 ° C. for 5 minutes to obtain a coating film, and the volume resistance value was determined according to the method described later.
Separately, the coating film was hot-pressed (120 ° C.) with a hydraulic laminator, and various evaluations were carried out according to the method described later. In the case of heat pressing, a release film or release paper may be placed on the coated object if necessary. In that case, the release film is peeled off before the physical property evaluation.

1. 1. Hot pressing method The coating film was hot pressed under the conditions shown below.
Flood control laminator machine used: Taisei Laminator Co., Ltd. Flood control laminator NP500S type Pump pressure: 2MPa
Roll speed: 0.2m / min
Upper and lower roll temperature: 120 ° C

2. Measurement of volume resistivity value The obtained composition and PET film laminate were cut into 1.5 cm x 3 cm, and the composition was used with a low resistivity meter (manufactured by Mitsubishi Chemical Analytech Co., Ltd .: Lorester GXMCP-T700). The volume resistivity value of was measured. In the case of "△", "○", "◎" evaluation, there is no problem in practical use.
・ Criteria for determining the conductivity of the coating film before pressing ◎: Volume resistance value is ^{less than 10-2} Ωcm ○: Volume resistance value is ^10-2 Ωcm or more and ^{less than 10 -1} Ωcm Δ: Volume resistance value is 10 ^-1 Ωcm or more, 10 ⁰ [Omega] cm less ×: conductive criterion volume resistivity of 10 ⁰ [Omega] cm or more, hot pressing after coating ○: volume resistivity of less than ^{10 -2} [Omega] cm △: volume resistivity of ^{10 -2} [Omega] cm or higher, 10 ^{- Less than 1} Ωcm ×: Volume resistance value is 10 ^-1 Ωcm or more

3. 3. Evaluation of print coatability The superiority or inferiority of print coatability was evaluated by the presence or absence of voids in the coating film. As an evaluation method, the degree of the number of voids when the coating film after hot pressing was viewed through with the light of a fluorescent lamp was evaluated in the following three stages.
◯: No voids △: There are slight voids, but there is no problem in evaluating conductivity ×: There are many voids and conductivity cannot be evaluated.

4. Evaluation of Adhesion of Coating Film The degree of peeling from the substrate after hot pressing was evaluated in the following three stages. Practically, there is no problem if it is "△" or more.
◯: No peeling △: Partial peeling ×: Complete peeling

5. Durability test The superiority and inferiority of durability was evaluated by the method shown below. The prepared heat-pressed coating film is immersed in salt water having a concentration of 3% together with a base material, left at 80 ° C. for 5000 hours, dried, and then the volume resistivity value is measured and the volume specificity before immersion is measured. The following evaluation was performed based on the resistance value. Practically, there is no problem if it is "△" or more. (The method for measuring the volume resistivity is the same as above)
○: △ not increase volume resistivity: The volume resistivity increases, ^10-2 maintains a value less than [Omega] cm ×: increased to volume resistivity of ^10-2 [Omega] cm or more

<Example 2>
Add a conductivity-imparting agent and an organic solvent to the binder resin A-1-a-1 in the types and amounts shown in Table 2, add glass beads (3 mm) having the same mass as the solution, and disperse by scandex. And the beads were removed. Next, 1031S: tetrakis (glycidyloxyphenyl) ethane ("Epicoat 1031S" manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent 180-220 g / eq (solid content 100%) was diluted with toluene to obtain a solid content of 50%. The curing agent solution D-1-1 was added in the blending amounts shown in Table 1 and then sufficiently stirred to obtain a conductive composition. The composition was applied to a PET film with an applicator 12 mil and then dried at 80 ° C. for 5 minutes to obtain a coating film. Then, various evaluations corresponding to Table 1 were carried out. Further, the obtained coating film was heat-pressed with a hydraulic laminator (120 ° C.) and cured under heating conditions of 150 ° C. for 30 minutes, and then various evaluations corresponding to Table 2 were carried out. In the case of heat pressing, a release film or release paper may be placed on the coated object if necessary. In that case, the release film is peeled off before the physical property evaluation.

<Example 3>
A conductivity-imparting agent and an organic solvent were added to the binder resin A-1-a-2 in the types and blending amounts shown in Table 2 and dispersed by three rolls. The conductive composition is printed on a PET film with a silk screen (40 mesh) and then dried at 100 ° C. for 10 minutes and at 150 ° C. for 60 minutes to obtain a coating film, and various physical characteristics corresponding to Table 1 are obtained. Evaluation was carried out. Further, the obtained coating film was hot-pressed with a hydraulic laminator (120 ° C.), and various physical property evaluations corresponding to Table 2 were carried out. The film thickness before pressing was 250 μm, and the film thickness after pressing was 80 μm.

<Examples 5, 9, 15, 19, 23, 29, 33, 37 to 45, Comparative Examples 1 to 8>
Except for the types and amounts of the formulations shown in Tables 2 to 7, the conductive composition was dispersed by Scandex in the same manner as in Example 1, and coated with an applicator to form a coating film for evaluation. bottom.

<Examples 4, 6, 8, 10, 12, 16, 18, 20, 22, 24, 26, 30, 32, 34, 36>
Except for the types and amounts of the formulations shown in Tables 2 to 5, the mixture was dispersed by scandex or three rolls in the same manner as in Example 1 or 3, and then a curing agent was added in the same manner as in Example 2. A conductive composition was obtained, coated with an applicator or printed by silk screen printing to form a coating and evaluated.

<Examples 7, 11, 13, 14, 17, 21, 25, 27, 28, 31, 35>
Except for the types and amounts of the formulations shown in Tables 2 to 6, the conductive composition was dispersed by three rolls in the same manner as in Example 3, and printed by silk screen printing to form a coating film. ,evaluated.

<Comparative Example 9>
A durability test was carried out using a commercially available copper foil having a film thickness of about 20 μm.

<Conductivity imparting agent (B)>
(Expanded graphite (B1))
-LEP (Nippon Graphite Industry): Average particle size 137 μm
CMX-40 (Nippon Graphite Industry): Average particle size 60 μm
GR-25 (Nippon Graphite Industry): Average particle size 31 μm
-EC10 (Ito Graphite Industry): Average particle size 190 μm
-EC100 (Ito Graphite Industry): Average particle size 190 μm
-EC300 (Ito Graphite Industry): Average particle size 50 μm
-EC1500 (Ito Graphite Industry): Average particle size 8 μm
(Scale graphite)
-CPB (Nippon Graphite Industry): Average particle size 38 μm
(Flake graphite)
-UP-50N (Nippon Graphite Industry): Average particle size 95 μm
(Carbon black (B2))
・ ECP600JD (Lion Specialty Chemicals)
・ EC300JD (Lion Specialty Chemicals)

<Organic solvent (C)>
-Toluene: Viscosity 0.66 mPa-s
・ MEK: 0.49mPa ・ s
・ IPA: 2.00 mPa ・ s
・ Terpineol: 53mPa ・ s
-Isobornylcyclohexanol: 70000 mPa · s
・ EDGAC: 2.6 mPa ・ s

<Hardener D>
1031S: Tetrakis (glycidyloxyphenyl) ethane ("Epicoat 1031S" manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent 180-220 g / eq (solid content 100%)
D-1-1: Epicoat 1031S was diluted with toluene to obtain a curing agent solution D-1-1 having a solid content of 50%.
D-1-2: Epicoat 1031S was diluted with terpineol to obtain a curing agent solution D-1-2 having a solid content of 50%.
-Sumijour BL3175: Blocked isocyanate curing agent ("Sumijuru BL3175" manufactured by Sumika Cobestro Urethane Co., Ltd. (solid content 75%))
D-2-1: Sumijoule BL3175 was diluted with toluene to obtain a curing agent solution D-2-1 having a solid content of 50%.
D-2-2: Sumijour BL3175 was diluted with terpineol to obtain a curing agent solution D-2-2 having a solid content of 50%.

In the table, dispersion by scandex is abbreviated as "S", dispersion by 3 rolls is abbreviated as "3", coating by an applicator is abbreviated as "A", and printing by silk screen printing is abbreviated as "SS".

Since Comparative Examples 1 to 3 did not use the optimum binder resin, the results were poor in conductivity and printability. In Comparative Examples 4 and 5, since the optimum binder resin was not used, the adhesion and durability were poor. In Comparative Example 6, since the average particle size of the expanded graphite was small, the conductivity was low. In Comparative Examples 7 and 8, since expanded graphite was not used, the conductivity was low. In Comparative Example 9, as a result of the durability test, a non-conductor was formed on the surface of the copper foil, and the durability evaluation was “x”.
Examples 1 to 45 use expanded graphite having a large average particle size and a binder resin having good adhesion to a substrate and sufficient coating film strength after hot pressing, and have high conductivity and a base. It showed good adhesion to the material.

Claims (7)

A conductive composition containing a binder resin (A), a conductivity-imparting agent (B), and an organic solvent (C), wherein the binder resin (A) is a polyolefin resin (A-1) and a styrene-based elastomer. Selected from the group consisting of the resin (A-2), the conductivity-imparting agent (B) contains expanded graphite (B1) and carbon black (B2) , and the average particle size of the expanded graphite is 10 μm or more and 200 μm or less. The conductive composition is characterized in that the content of the conductivity-imparting agent (B) is 40% by mass or more and 90% by mass or less in 100% by mass of the solid content of the composition. The conductive composition according to claim 1, wherein the expanded graphite (B1) has an average particle size of 25 μm or more and 150 μm or less. The conductive composition according to claim 1 or 2, wherein the formed conductor film has a volume resistance value of 10 ^-3 Ωc or more and ^{less than 10 -1 Ω cm.} The organic solvent (C) contains an organic solvent (C1) having a viscosity of 30 mPa · s or more and 75,000 mPa · s or less at 25 ° C., and the content of the organic solvent (C1) is 100 mass by mass of the organic solvent (C). The conductive composition according to any one of claims 1 to 3 , wherein the content is 10% by mass or more in%. The volume resistance value of the conductor film obtained by hot-pressing the conductor film obtained by applying the conductive composition to the substrate and then drying it is 10 ^-4 Ωcm or more and ^{less than 10 -2} Ω cm. The conductive composition according to any one of claims 1 to 4 , wherein the conductive composition is characterized by this. A method for producing a conductor film, which comprises applying the conductive composition according to any one of claims 1 to 5 to a base material and then heat-pressing the conductor film obtained by drying. A method for producing a conductor film, which comprises patterning the conductive composition according to any one of claims 1 to 5 by screen printing to form conductor wiring.