JP2019012663A - Conductive composition and method for producing conductor film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition having good corrosion resistance, exhibiting excellent conductivity, and suitable for printing and coating. A conductive composition containing a binder resin (A), a conductivity-imparting agent (B), and an organic solvent (C), wherein the binder resin (A) has a number average molecular weight of 800 or more 7, Selected from the group consisting of a bisphenol type epoxy resin (A-1) having a number of less than 000 and a phenoxy resin (A-2) having a number average molecular weight of 7,000 or more and less than 60,000, the conductivity-imparting agent (B) is expanded graphite. The average particle size of the expanded graphite containing (B1) is 10 μm or more and 200 μm or less, and the content of the conductivity-imparting agent (B) is 40% by mass or more and 90% by mass in 100% by mass of the solid content of the composition. A conductive composition having a mass% or less. [Selection diagram] None

Description

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

In recent years, conductive paints using conductive resin compositions, conductive adhesives, and the like are increasing from the viewpoints of weight reduction of products, consideration for the environment, and reduction of 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, particularly 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.
As a conductive composition using a conductive carbon filler, a low-resistance conductive composition has been studied using graphite, carbon nanotubes, and the like (Patent Documents 2 and 3). However, it is difficult to develop high electrical conductivity compared to metal fillers, and carbon-based fillers are lighter in specific gravity than metals and carbon in the composition to exhibit high electrical conductivity. When the filling amount of the system filler is increased, 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 that has good corrosion resistance, exhibits excellent electrical conductivity, and is suitable for printing coating.

  As a result of intensive studies to solve the above problems, the present inventors have found that printing can be performed while exhibiting high conductivity with the conductive composition shown below, and the present invention has been completed.

  That is, the present invention is 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 bisphenol-type epoxy resin ( Selected from the group consisting of A-1) and a phenoxy resin (A-2), wherein the conductivity-imparting agent (B) contains expanded graphite (B1), and the average particle size of the expanded graphite is 10 μm or more, It is 200 micrometers or less, Comprising: It is related with the electroconductive composition characterized by being 40 mass% or more and 90 mass% or less in 100 mass% of solid content of a composition.

  The present invention also relates to the above 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 conductive composition, wherein the formed coating film has a volume resistance value of 10 ⁻³ Ωcm or more and less than 10 ⁻¹ Ωcm.

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

  The present invention also includes an organic solvent (C1) having an organic solvent (C1) having a viscosity at 25 ° C. of 30 mPa · s or more and 75000 mPa · s or less, and the organic solvent (C1) content is organic. It is related with the said electroconductive composition characterized by being 10 mass% or more in content of a solvent (C) 100 mass%.

  Moreover, this invention relates to the manufacturing method of the conductor film characterized by heat-pressing the conductor film obtained by apply | coating the said electroconductive composition to a base material, and drying.

The present invention also relates to the method for producing a conductor film, wherein the conductor film has a volume resistance value of 10 ⁻⁴ Ωcm or more and less than 10 ⁻² Ωcm.

  The present invention also relates to a method for producing a conductor film, wherein the conductive composition is patterned on a substrate by screen printing to form a conductor wiring.

  According to the present invention, it is possible to provide a composition that has good corrosion resistance, exhibits high electrical conductivity, and is suitable for print coating.

Hereinafter, embodiments of the present invention will be described.
The conductive composition of the present invention (hereinafter sometimes referred to as “composition”) includes 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 a bisphenol type epoxy resin (A-1) and a phenoxy resin (A-2) from the viewpoints of volume resistivity, adhesion to a substrate, and durability. The volume resistance value is good because the resin component in the hot press easily flows.
The bisphenol type epoxy resin (A-1) has a relatively low molecular weight (number average molecular weight of 800 or more and less than 7,000) and is expected to react with an epoxy group as a functional group. On the other hand, the phenoxy resin (A-2) has a relatively high molecular weight (number average molecular weight of 7,000 or more and less than 60,000) and does not have an epoxy group, as will be described later. Is small and sometimes recognized as a thermoplastic resin.

[Bisphenol type epoxy resin (A-1)]
The bisphenol type epoxy resin (A-1) is an epoxy resin containing a molecular skeleton derived from a bisphenol compound and one or more epoxy groups in one molecule.
Such a bisphenol type epoxy resin (A-1) comprises, for example, a compound having two or more hydroxyl groups in one molecule containing at least a bisphenol compound and epichlorohydrin in the presence of a base such as sodium hydroxide. Although it can be obtained by a publicly known method for polymerization, the synthesis method is not limited as long as a resin having a similar structure is obtained.
In addition, as long as the bisphenol compound is used as an essential component, it is copolymerized with components other than the bisphenol compound such as an aliphatic diol compound, a polyether polyol compound, and a liquid rubber compound such as a carboxy nitrile-terminated butadiene nitrile rubber (hereinafter referred to as CTEN). May be. Furthermore, an amine-modified product obtained by reacting the epoxy resin with an amine compound, a side-chain modified product obtained by adding ethylene oxide, propylene oxide, ε-caprolactone, etc. to the side chain hydroxyl group, and a part of bisphenols are acetal bonded. The acetal modified body etc. which were connected by these can also be used.

  The bisphenol compound may be a bifunctional phenol compound obtained as a condensate of two molecules of a phenol compound and one molecule of a ketone or aldehyde compound. For example, bisphenol F, bisphenol A, bisphenol S, bisphenol C, bisphenol E, Bisphenol Z, Bisphenol G, Bisphenol TMC, Bisphenol M and BisP-AP, TM-BPF, BisOC-F, BisP-MIBK, BisP-B, BisOPP-A, BisOCHP-A, Bis26X-A, BisOTBH-A, Methylenebis Examples include P-CR (product name of Honshu Chemical Industry Co., Ltd.), bisphenol P, bisxylenol P (product name of Mitsubishi Chemical Fine Co., Ltd.), bisphenol fluorene, and hydrogenated products thereof. It is. These may be used alone as a synthetic raw material or in combination of two or more.

  Examples of such commercially available products of bisphenol type epoxy resin (A-1) include bisphenol A type epoxy resins such as jER828, jER1007, jER1010, and YL6810 (manufactured by Mitsubishi Chemical Corporation), jER806, jER4004P, jER4010P (Mitsubishi Chemical). Bisphenol F type epoxy resin such as EPOK-MK R-710, EPOK-MK R-1710 (manufactured by Printec), YX8000, YX8034 (manufactured by Mitsubishi Chemical), ST- 3000, ST-4000D (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), hydrogenated bisphenol A type epoxy resin, jER-872 (manufactured by Mitsubishi Chemical Co., Ltd.), dimer acid-modified epoxy resin, EXA-4850-150, EXA- 4850-1000 (DI Acetal-modified bisphenol A type epoxy resin such as EXA-4816 (manufactured by DIC), EPR-1415-1, EPR-2000 (manufactured by ADEKA) NBR-modified bisphenol A-type epoxy resins such as, but not limited to. These may be used alone or in combination of two or more.

<Phenoxy resin (A-2)>
The phenoxy resin (A-2) used in the present invention is obtained by polymerizing the bisphenol compound and epichlorohydrin or the bisphenol compound and an epoxy compound having at least two epoxy groups in one molecule. It has a relatively high molecular weight (number average molecular weight of about 7,000 to less than 60,000).
When the phenoxy resin (A-2) has an epoxy group, the difference from the bisphenol type epoxy resin (A-1) is the number average molecular weight.
In addition, it has a structure derived from the reaction of a bisphenol compound and epichlorohydrin or a bifunctional or higher functional epoxy compound, and has a relatively high molecular weight as described above, the epoxy group in the resin is bonded to the epoxy group. A compound in which an epoxy group is eliminated by reacting a compound having reactivity with a group can also be used as the phenoxy resin (A-2).
Further, as in the case of the bisphenol-type epoxy resin (A-1), the side chain hydroxyl group resulting from the reaction of the bisphenol compound with epichlorohydrin, etc., alkylene oxides such as ethylene oxide and propylene oxide, ε-caprolactone, A side-chain modified product to which lactones such as δ-valerolactone, acid anhydrides such as succinic anhydride, maleic anhydride, phthalic anhydride, and tetrahydrophthalic anhydride, and monofunctional isocyanates such as octadecyl isocyanate are added. Also good.

  As the epoxy compound having two epoxy groups in one molecule, the above-mentioned bisphenol type epoxy resin (A-1) may be used, and in other cases, hexanediol diglycidyl ether, nonanediol diglycidyl ether, etc. Aliphatic diglycidyl ether, dimer acid diglycidyl ester such as jER871 (Mitsubishi Chemical), polyethylene glycol diglycidyl ether such as Epolite 200E and Epolite 400E (Kyoeisha Chemical), Epolite 70P and Epolite 400P (Kyoeisha Chemical Co., Ltd.) Polypropylene glycol diglycidyl ether such as YX4000 and YL8121, anthracene diglycidyl ether such as YX8800 (manufactured by Mitsubishi Chemical), GAN, GO (Manufactured by Nippon Kayaku Co., Ltd.) diglycidyl amine such as, but not limited thereto. These epoxy compounds having two epoxy groups in one molecule may be polymerized using only one kind, or two or more kinds may be used in combination.

Moreover, as long as the characteristics required for the present invention are satisfied, when a phenoxy resin (A-2) is obtained by reacting a bisphenol compound with an epoxy compound having two epoxy groups in one molecule, further in one molecule. An epoxy compound having one epoxy group or an epoxy compound having three or more epoxy groups in one molecule may be used in combination.
Examples of the epoxy compound having one epoxy group in one molecule include aliphatic monofunctional epoxy compounds such as butyl glycidyl ether (manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.), Epolite M-1230 (manufactured by Kyoeisha Chemical Co., Ltd.), SY- And aromatic monofunctional epoxy compounds such as OCG and SY-OPG manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.
Examples of the epoxy compound having three or more epoxy groups in one molecule include TEPIC series (manufactured by NOF Corporation) and jER630 (manufactured by Mitsubishi Chemical Corporation).

  Examples of such commercially available products of phenoxy resin (A-2) include, for example, jER-1256 (manufactured by Mitsubishi Chemical Corporation), YP-50 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), PKFE, PKHH (Gabriel Performance Products, Inc.) Bisphenol A type phenoxy resin such as jER-4275 (manufactured by Mitsubishi Chemical Co., Ltd.), YP-70 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), bisphenol A / bisphenol F copolymer phenoxy resin, YPS-007A30 (new) Bisphenol A / bisphenol S copolymer type phenoxy resin such as Nippon Steel & Sumikin Chemical Co., Ltd., side chain caprolactone-modified bisphenol A type phenoxy resin such as PKCP-67 and PKCP-80 (manufactured by Gabriel Performance Products), KAYARAD ZFR-1901, KAYARAD ZAR-2000 (Japan Side chain anhydride modified products such as Kayaku Co., Ltd.).

In the present invention, the bisphenol type epoxy resin (A-1) or phenoxy resin (A-2) and another binder resin may be used in combination. Examples of binder resins that can be used in combination include polyurethane, acrylonitrile, acrylic, butadiene, polyamide, polyvinyl butyral, polyolefin, polyester, polystyrene, EVA, polyvinylidene fluoride, and silicon resins. 1 type or more chosen from the group which consists of can be included. It is not necessarily 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 flaky graphite (also referred to as expandable graphite; Expandable Graphite), which is expanded by heat treatment and then refined. In addition, the expanded graphite powder obtained by pulverizing what was rolled into a graphite sheet before refining is also included.
The expanded graphite can be appropriately selected from conventionally known expanded graphite. Commercially expanded graphite may be used. Examples of commercially available expanded graphite include EC1500, EC1000, EC500, EC300, EC100, and EC50 (all are trade names) manufactured by Ito Graphite Industries.
The shape of the expanded graphite is not particularly limited. For example, flaky expanded graphite further processed into a flaky shape can be mentioned.
Expanded graphite can exhibit high conductivity with a small content compared to other graphites. For example, there is a tendency that high conductivity is expressed in a smaller amount than general scale-like graphite.
The average particle diameter of the expanded graphite is 10 μm to 200 μm, and more preferably 25 to 150 μm. The thickness is preferably 10 μm or more from the viewpoint of improving the conductivity of the conductive film to be formed, and is 200 μm or less from the viewpoint of the coating property of the conductive composition and the adhesion of the conductive film to be formed to the substrate. preferable.
Moreover, it is preferable that the difference of the particle size of D10 (micrometer) and D90 (micrometer) is 60 micrometers 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 an integrated value of 10% and a particle size of 90%.
Measurement shall be performed under the following conditions.
Measuring instrument: Microtrack MT3300EXII (Microtrack Bell Co., Ltd.)
Measurement sample adjustment method: 0.63 g of graphite and 11.87 g of toluene were added to a glass bottle with a lid (M-70), and then dispersed by planetary stirring (Sinky Co., Ltd .: Ryotaro Awatori, stirring time: 3 minutes). Prepare the liquid and perform the measurement.
The content of the conductivity-imparting agent (B1) when the solid content of the conductive composition is 100% by mass is 40% by mass to 90% by mass, and more preferably 50% by mass to 85% by mass. . 40 mass% or more is preferable from the point of the electroconductive improvement of the electrically conductive film formed, and 90 mass% or less is preferable from the point of the adhesiveness to the base material of the electrically conductive composition formed and the electrically conductive film formed.

(Carbon black (B2))
In the present invention, carbon black can be used in combination as the conductivity imparting agent. By using the expanded graphite and carbon black in combination, the carbon black plays a role of connecting the conductive path of the expanded graphite, and tends to exhibit high conductivity even without going through a hot press process.
As the carbon black, conventionally known conductive carbon such as acetylene black, ketjen black, and furnace black can be used.
The mass composition ratio between expanded graphite (B1) and carbon black (B2) is as follows. When the total mass of expanded graphite and carbon black is 100% by mass, expanded graphite is 60 to 90% by mass, and carbon black is 10%. -40 mass% is preferable. Carbon black (B2) is preferably 40% by mass or less from the viewpoint of utilizing the high conductivity derived from expanded graphite, and carbon black (B2) is 10% by mass or more from the viewpoint of connecting a conductive path between the expanded graphite. It 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 is not limited as long as the physical properties are not impaired. Moreover, 1 type (s) or 2 or more types can also be used together.

<Organic solvent (C)>
Organic solvents include alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol methyl ether, diethylene glycol methyl ether, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, etc. Suitable for the composition of the conductive composition from among ethers such as hexane, heptane, octane and other hydrocarbons, benzene, toluene, xylene, cumene and other aromatics, ethyl acetate, butyl acetate and other esters Can be used. Two or more solvents may be used. Mass In addition, when adopting a printing coating method such as screen printing that requires a certain viscosity or more, the viscosity at 25 ° C. is an organic solvent (C1) of 30 mPa · s to 75000 mPa · s. It is preferable to contain 10% by mass or more in 100% by mass of the organic solvent (C). From the viewpoint of improving the conductivity of the conductive film to be formed, it is desired 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 applicability of the conductive composition also decreases. From the viewpoint of improving the dispersibility of the conductivity-imparting agent (B) and functioning as a “pseudo binder” that makes the conductive composition suitable for coating, use an organic solvent of 30 mPa · s or more at 25 ° C. Is preferred. On the other hand, from the viewpoint of improving the dispersibility of the conductivity-imparting agent (B), the viscosity is preferably not too high. Specifically, it is preferable to use an organic solvent of 75000 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 high-viscosity solvents shown here may be used.
Furthermore, the organic solvent (C1) can be used in combination with a low viscosity solvent having a viscosity of less than 30 mPa · s at 25 ° C., such as methyl ethyl ketone, toluene, and isopropyl alcohol.

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

<Other ingredients>
In the conductive composition of the present invention, an ultraviolet absorber, an ultraviolet stabilizer, a radical scavenger, a filler, a thixotropy imparting agent, an anti-aging agent, and an antioxidant are added to the conductive composition of the present invention, as necessary. Agent, antistatic agent, flame retardant, thermal conductivity improver, plasticizer, anti-sagging agent, antifouling agent, antiseptic, disinfectant, antifoaming agent, leveling agent, anti-blocking agent, curing agent, thickener, Various additives such as a pigment dispersant and a silane coupling agent may be added.
<Curing agent D>
The curing agent is not particularly limited as long as it reacts with the functional group of the binder resin. In addition to a compound having a plurality of amino groups or a compound having a plurality of acid anhydride groups, a polyfunctional aziridine compound, a polyfunctional isocyanate. Compounds and the like.

<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, if necessary, mixing other components and then uniformly dispersing them. .
The dispersing method is carried out by dissolving the binder resin in a solvent and adding a conductive filler, followed by planetary stirring, three-roll, two-roll, scandex, or bead mill. The solvent to be 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 lowered.
However, when using a hardening | curing agent, addition of a hardening | curing agent shall be performed after dispersion | distribution of an electroconductive composition. 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>
The base material is polyethylene terephthalate (hereinafter referred to as PET), polyethylene-2,6-naphthalate (hereinafter referred to as PEN), polyimide, polyvinyl chloride, polyamide, biaxially stretched polypropylene (hereinafter referred to as OPP), unstretched polypropylene ( Hereinafter, a film such as CPP) may be mentioned, but the film is not particularly limited.

<Conductor film>
The conductor film of the present invention is formed by applying a conductive composition and drying.
The method for applying the conductive composition to the substrate is shown below. The coating method may be a known method, such as an inkjet method, a spray method, a spin coating method, a dip method, a roll coating method, a blade coating method, a doctor roll method, a doctor blade method, a curtain coating method, a slit coating method, A screen printing method, a reverse printing method, and the like can be given, but not particularly limited.
Drying conditions are not particularly limited, and examples include those using hot air drying, infrared rays or a reduced pressure method. In the case of hot air drying, although it depends on the film thickness and the selected organic solvent, it is usually dried at about 60 to 200 ° C. Moreover, when using plastic films, such as PET and PEN, as a base material, since a base material may deform | transform with heat, 60-150 degreeC is more preferable.
When using a conductive film as the conductor wiring, the film thickness after coating is preferably 50 to 1000 μm from the viewpoints 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.

<Hot press method>
The hot pressing method may be any method as long as the conductive film and the substrate are not damaged. For example, a roll pressurization method, a press pressurization method, etc. are mentioned. The pressure, temperature, press time, and roll speed are not particularly limited as long as the physical properties of the present invention are not impaired. Regarding the temperature, when a film substrate is used, it may be deformed by heat, and therefore, 50 ° C to 200 ° C is preferable.
When using the composition as a conductor wiring, the film thickness after hot pressing is preferably 30 to 200 μm.

  The present invention will be described more specifically with reference to the following examples. However, the following examples do not limit the scope of rights of the present invention. 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) jER-1007: bisphenol A type epoxy resin manufactured by Mitsubishi Chemical Corporation, solid content 100%, number average molecular weight 2,900
(A-1-b) jER-4010P: bisphenol F type epoxy resin manufactured by Mitsubishi Chemical Corporation, solid content 100%, number average molecular weight 5,500
(A-1-c) EXA-4850-150: DIC Acetal-modified bisphenol A epoxy resin, solid content 100%, number average molecular weight 1,000
(A-2-a) jER-1256: bisphenol A phenoxy resin manufactured by Mitsubishi Chemical Corporation, solid content 100%, number average molecular weight 10,000
(A-2-b) PKFE: Bisphenol A type phenoxy resin manufactured by Gabriel Performance Products, number average molecular weight 16,000
(A-2-c) jER-4275: bisphenol A / bisphenol F copolymer phenoxy resin manufactured by Mitsubishi Chemical Corporation, solid content 100%, number average molecular weight 8,000
(A-2-d) PKCP-67: Side chain ε-caprolactone modified bisphenol A type phenoxy resin manufactured by Gabriel Performance Products, solid content 100%, number average molecular weight 22,500
(A-2-e) KAYARAD ZFR-1491: Nippon Kayaku Co., Ltd. side chain tetrahydrophthalic anhydride / glycidyl acrylate modified bisphenol F type phenoxy resin, solid content 50% (methoxypropyl acetate solution), number average molecular weight 12 , 000

<For comparative example>
(A-3-a) N-730A: DIC, phenol novolac epoxy resin, solid content 100%
(A-3-b) Nipol AR42W: manufactured by Nippon Zeon, acrylic rubber polymer, solid content 100%
(A-3-c) ESREC BM-2: Sekisui Chemical Co., Ltd., polyvinyl butyral, 100% solid content
(A-3-d) Shounol BRG-556: Aika SDK Phenol, novolak type phenol resin, solid content 100%
(A-3-e) JP03: Made of Nippon Vinegar and Poval, polyvinyl alcohol, solid content 100%
(A-3-f) K-30: manufactured by Nippon Shokubai, polyvinylpyrrolidone, solid content 100%

<Measuring method of number average molecular weight (Mn)>
For measurement of Mn, GPC (gel permeation chromatography) “HPC-8020” manufactured by Tosoh Corporation was used. GPC is liquid chromatography that separates and quantifies substances dissolved in a solvent (THF; tetrahydrofuran) based on the difference in molecular size. For the measurement in the present invention, “LF-604” (manufactured by Showa Denko KK: GPC column for rapid analysis: 6 mm ID × 150 mm size) is connected in series to the column, the flow rate is 0.6 ml / min, the column temperature. The measurement was performed at 40 ° C., and the mass average molecular weight (Mn) was determined in terms of polystyrene.

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

<Example 1>
Add the conductivity-imparting agent and organic solvent to the binder resin A-1-a-1 solution in the types and amounts shown in Table 2, and finally add glass beads (3 mm) of the same mass as the solution. After conducting dispersion with scandex and removing the beads, 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. The volume resistance value was determined according to the method described later.
Separately, the above-mentioned coating film was hot-pressed (120 ° C.) with a hydraulic laminator, and various evaluations were performed according to methods described later. In the case of hot pressing, a release film and release paper may be installed on the coated material as necessary. In that case, the release film is peeled off before the physical property evaluation.

1. Hot press method The hot press of the coating film was implemented on condition shown below.
Used hydraulic laminator machine: Taisei Laminator Co., Ltd. hydraulic laminator NP500S pump pressure: 2MPa
Roll speed: 0.2m / min
Upper and lower roll temperature: 120 ° C

2. Measurement of Volume Resistivity Value A laminate of the obtained composition and a PET film was cut into 1.5 cm × 3 cm, and the composition was measured using a low resistivity meter (manufactured by Mitsubishi Chemical Analytech Co., Ltd .: Lorester GXMCP-T700). The volume resistance value of was measured. In the case of “△”, “◯”, “◎” evaluation, there is no practical problem.
Criteria for judging conductivity of coating film before press A: Volume resistance value is less than 10 ⁻² Ωcm ○: Volume resistance value is 10 ⁻² Ωcm or more, 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 x: Volume resistance value is 10 ⁻¹ Ωcm or more

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, evaluation was carried out in the following three stages according to the degree of the number of voids when the coated film after hot pressing was viewed through a fluorescent lamp.
○: No void Δ: There is a slight void, but there is no problem for the evaluation of conductivity. ×: There are many voids and the 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. In practice, there is no problem if it is greater than “Δ”.
○: No peeling △: Partial peeling ×: Complete peeling

5. Durability test The durability was evaluated by the following method. The prepared heat-pressed coating film was immersed in 3% salt water together with the base material, allowed to stand at 80 ° C. for 5000 hours, and then dried, and then measured for volume resistivity. The following evaluation was performed based on the resistance value. There is no problem if it is more than “△” in practical use. (Measurement method of volume resistivity is the same as above)
○: Volume resistance value does not increase Δ: Volume resistance value increases, but maintains a value of less than 10 ⁻² Ωcm ×: Volume resistance value increases to 10 ⁻² Ωcm or more

<Example 2>
Add the conductivity-imparting agent and the organic solvent to the binder resin A-1-a-1 in the types and amounts shown in Table 2, add glass beads (3 mm) of the same mass as the solution, and disperse by Scandex. And the beads were removed. Next, Sumidur BL3175: Sumika Covestro Urethane Co., Ltd. Block isocyanate curing agent (solid content: 75%) diluted with toluene to contain a curing agent solution D-1-1 having a solid content of 50% is shown in Table 1. After the addition in an amount, the mixture was 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.
And various evaluation corresponding to Table 1 was implemented. Furthermore, the obtained coating film was hot-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 performed. In the case of hot pressing, a release film and release paper may be installed on the coated material as 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 with a three-roll. The conductive composition was 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. Various physical properties corresponding to Table 1 Evaluation was performed. Furthermore, the obtained coating film was hot-pressed with a hydraulic laminator (120 ° C.), and various physical properties corresponding to Table 2 were evaluated. The film thickness before pressing was 250 μm, and the film thickness after pressing was 80 μm.

<Examples 5, 9, 13, 17, 21, 27, Comparative Examples 1-8>
Except for the types and amounts of the formulations described 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. Evaluation did.

<Examples 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 28, 30, 34, 36>
Except for the types and amounts of the compounds listed in Tables 2 to 5, after being dispersed by scandex or three rolls in the same manner as in Example 1 or 3, a curing agent was added in the same manner as in Example 2. A conductive composition was obtained and applied with an applicator or printed with silk screen printing to form a coating and evaluated.

<Examples 7, 11, 15, 19, 23, 25, 26, 29, 31, 32, 35>
Except for the types and amounts of the compounds listed in Tables 2 to 6, a conductive composition was obtained by dispersing with 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>
The durability test was conducted with a commercially available copper foil having a thickness of about 20 μm.

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

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

<Curing agent D>
・ Sumijour BL3175: Sumika Cobestro Urethane Co., Ltd. Block isocyanate curing agent (solid content 75%)
D-1-1: Sumidur BL3175 was diluted with toluene to obtain a curing agent solution D-1-1 having a solid content of 50%.
D-1-2: Sumidur BL3175 was diluted with terpineol to obtain a curing agent solution D-1-2 having a solid content of 50%.
・ Rikacid TH: Tetrahydrophthalic anhydride (solid content 100%) manufactured by Shin Nippon Rika Co., Ltd.
D-2-1: Ricacid TH was diluted with toluene to obtain a curing agent solution D-2-1 having a solid content of 50%.
D-2-2: Ricacid TH was diluted with terpineol to obtain a curing agent solution D-2-2 having a solid content of 50%.
-Cure sol 2E4MZ: Shikoku Kasei Co., Ltd. imidazole hardening | curing agent (solid content 100%) was D-3-1: Curazole 2E4MZ was diluted with toluene, and the hardening | curing agent solution D-3-1 of 50% of solid content was obtained.
D-3-2: Curazole 2E4MZ was diluted with terpineol to obtain a curing agent solution D-3-2 having a solid content of 50%.

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

Since Comparative Examples 1-3 did not use the optimal binder resin, it was a result with bad electroconductivity and printability. In Comparative Examples 4 and 5, since an optimal 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. Comparative Examples 7 and 8 had low conductivity because expanded graphite was not used. In Comparative Example 9, as a result of the durability test, a nonconductor was formed on the surface of the copper foil, and the durability evaluation was “x”.
Examples 1 to 47 use expanded graphite having a large average particle size and a binder resin having good adhesion to a substrate and sufficient coating strength after hot pressing, and have high conductivity and basicity. It showed good adhesion to the material.

Claims (8)

  A conductive composition containing a binder resin (A), a conductivity imparting agent (B), and an organic solvent (C), wherein the binder resin (A) has a number average molecular weight of 800 or more and less than 7,000. Selected from the group consisting of a type epoxy resin (A-1) and a phenoxy resin (A-2) having a number average molecular weight of 7,000 or more and less than 60,000, and the conductivity-imparting agent (B) is an expanded graphite (B1). The expanded graphite has an average particle size of 10 μm or more and 200 μm or less, and 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. A conductive composition characterized by being.   2. 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. 3. The conductive composition according to claim 1, wherein a volume resistance value of the formed coating film is 10 ⁻³ Ωc or more and less than 10 ⁻¹ Ωcm.   Furthermore, electroconductivity imparting agent (B) contains carbon black (B2), The electroconductive composition of any one of Claims 1-3 characterized by the above-mentioned.   The organic solvent (C) contains an organic solvent (C1) having a viscosity at 25 ° C. of 30 mPa · s or more and 75000 mPa · s or less, and the content of the organic solvent (C1) is the content of the organic solvent (C). It is 10 mass% or more in quantity 100 mass%, The electrically conductive composition of any one of Claims 1-4 characterized by the above-mentioned. After the conductive composition is applied to the substrate, the conductor film obtained by drying the conductor film has a volume resistance of 10 ⁻⁴ Ωcm or more and less than 10 ⁻² Ωcm. The conductive composition according to any one of claims 1 to 5, wherein:   A method for producing a conductor film, comprising: applying a conductive composition according to any one of claims 1 to 6 to a substrate, and then hot-pressing the conductor film obtained by drying. A method for producing a conductor film, wherein the conductive composition according to any one of claims 1 to 6 is patterned by screen printing to form a conductor wiring.