JP7059873B2 - Conductive compositions, and conductive films - Google Patents

Description

The present invention relates to a conductive composition containing a binder resin and a carbon material.

In recent years, the development of electronics has been remarkable, and conductive materials used in various electronic devices are required to be smaller and lighter, cost lower, and have a longer life in various usage environments. It's coming. For example, when manufacturing a board wiring of an electronic device or a wiring for connecting an electronic device, a conductive composition having good conductivity is required, but a conductive composition using a metal filler such as silver or copper is generally used. However, the big problem in terms of cost has not been solved yet. On the other hand, various studies have been made on conductive compositions using conductive carbon that does not use metal, but due to insufficient conductivity, they have been limited to use in semi-conductive applications such as antistatic applications. rice field.

Further, as the conductive carbon material, various good conductive materials having a low volume resistivity such as graphite and carbon nanotubes have been studied to date. The volume resistivity of these carbon materials with good conductivity is as high as less than ^10-2 Ω · cm, but many carbon materials with excellent conductivity have a large specific surface area and are uniform to resins and solvents. It may be difficult to mix and disperse, and poor contact between the carbon materials in the coating film or molded product obtained from the conductive carbon material, resin, solvent, etc. may occur. The problem was that the conductivity could not be sufficiently exhibited (Patent Documents 1 to 3).
Therefore, Patent Documents 4 to 18 disclose conductive compositions in which graphite and carbon black are used in combination and dispersed in a binder in order to develop a conductive network between carbon materials in the coating film.

Patent Documents 17 and 18 disclose a mixing ratio of a resin and a conductive carbon material, and a correlation between a mixing ratio of graphite and carbon black and conductivity. The contact state between the carbon materials in the coating film and the molded product changes depending on the mixing ratio of the resin and the conductive carbon material and the mixing ratio of graphite and carbon black, and the conductivity may reach the maximum value under predetermined conditions. Although shown, the study conditions were broad and discrete, and were not exhaustively verified.

Further, Patent Documents 19 and 20 also disclose a conductive composition using carbon fibers and carbon nanotubes in combination. Although the conductivity was improved by strengthening the conductive network, there is room for improvement in the dispersibility of the conductive carbon material with respect to resins and solvents, and the volume resistivity of the coating film is also on the order of ^10-2 Ω · cm. I often stayed at.

Therefore, in order to improve the dispersibility, the dispersion method is changed in Patent Document 21, the use of the dispersant in the organic solvent-based composition is used in Patent Documents 22 and 23, and the aqueous dispersion in the aqueous composition is used in Patent Documents 24 and 25. The use of the agent is disclosed. However, although the dispersibility has been improved, there is a problem that the conductivity is lowered by adding a dispersant which is an insulating material or damaging the conductive carbon material by miniaturization.

Japanese Unexamined Patent Publication No. 3-7740 Japanese Unexamined Patent Publication No. 2001-60413 Japanese Patent Application Laid-Open No. 2002-20515 Japanese Unexamined Patent Publication No. 54-36343 Japanese Unexamined Patent Publication No. 62-88260 Japanese Unexamined Patent Publication No. 62-88261 Japanese Unexamined Patent Publication No. 62-199663 Japanese Unexamined Patent Publication No. 63-125580 Japanese Unexamined Patent Publication No. 64-56777 Japanese Unexamined Patent Publication No. 1-101373 Japanese Unexamined Patent Publication No. 1-184901 Japanese Unexamined Patent Publication No. 2-284966 Japanese Unexamined Patent Publication No. 5-65366 Japanese Unexamined Patent Publication No. 7-33883 Japanese Unexamined Patent Publication No. 7-41609 Japanese Unexamined Patent Publication No. 7-53813 Japanese Unexamined Patent Publication No. 2001-102010 Japanese Patent Application Laid-Open No. 2003-23881 Japanese Unexamined Patent Publication No. 6-12278 Japanese Unexamined Patent Publication No. 2004-221071 Japanese Unexamined Patent Publication No. 2-204317 Japanese Unexamined Patent Publication No. 2001-254013 Japanese Unexamined Patent Publication No. 2013-119757 Japanese Unexamined Patent Publication No. 2004-10705 JP-A-2015-128006

An object of the present invention is to provide a conductive composition having excellent conductivity, in which the mixing ratio of a binder resin and a carbon material and the mixing ratio of graphite as a carbon material and carbon other than graphite are set within a specific range. It is an object of the present invention to provide a conductive composition and a conductive film having specifically excellent conductivity and adhesion.

That is, the present invention is a conductive composition containing a binder resin (A) and a carbon material (B).
The carbon material (B) contains graphite (B-1) and a carbon material other than graphite (B-2).
The mass ratio of the solid content of the binder resin (A) to the carbon material (B) is 15:85 to 35:65.
The present invention relates to a conductive composition characterized in that the content of graphite (B-1) is 75.0 to 99.0% by mass in 100% by mass of the carbon material (B).

The present invention also relates to the above-mentioned conductive composition, wherein the content of graphite (B-1) is 80.0 to 99.0% by mass in 100% by mass of the carbon material (B). ..

The present invention also relates to the above-mentioned conductive composition, wherein the content of graphite (B-1) is 90.0 to 97.5% by mass in 100% by mass of the carbon material (B). ..

The present invention also relates to the above-mentioned conductive composition, characterized in that the mass ratio of the solid content of the binder resin (A) to the carbon material (B) is 20:80 to 30:70.

The present invention relates to the above-mentioned conductive composition, wherein the binder resin (A) contains polyurethane, polyamide, or polyester.

The present invention also relates to the above-mentioned conductive composition, wherein the carbon material (B-2) other than graphite contains carbon black.

The present invention also relates to a conductive film obtained by using the above-mentioned conductive composition.

In a conductive composition containing a binder resin (A) and a conductive carbon material (B), a mixing ratio of the binder resin and the conductive carbon material and a mixture of graphite and carbon other than graphite as the conductive carbon material. When the ratio is in a specific range, the carbon materials in the conductive film formed by the conductive composition have good contact and binding properties, so that an excellent conductive network is formed and the conductivity is excellent. A conductive film can be provided.

<Conductive composition>
The conductive composition of the present invention contains a binder resin (A), a carbon material (B), and if necessary, a solvent.

The appropriate viscosity of the conductive composition depends on the coating method of the conductive composition, but is generally preferably 10 mPa · s or more and 30,000 mPa · s or less.

First, the binder resin (A) will be described.

The binder resin is selected from the group consisting of polyurethane-based, polyamide-based, acrylonitrile-based, acrylic-based, butadiene-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. In particular, polyurethane-based, polyamide-based, and polyester-based are preferable. However, it is not limited to these resins. The binder resin may be used alone or in combination of two or more.
The binder resin can also be a curable resin that undergoes a curing (crosslinking) reaction after the binder resin is applied to the substrate.
That is, the binder resin is selected to be self-curing or combined with a curing agent described later, and the conductive composition is printed or coated on the substrate and then cured (crosslinked). You can also.

As the binder resin, a polyurethane resin is preferable from the viewpoint of volume resistivity, adhesion to a substrate and durability. After printing or coating the conductive composition on the substrate, when (heat) pressing, the resin component softens, and the flat pattern shape of the conductive film during printing and coating is almost maintained. On the other hand, when it flows in the thickness direction, the voids can be reduced and the contact between the conductive carbon materials (B) can be increased, so that the volume resistivity of the obtained conductive film can be expected to decrease. Therefore, as the binder resin, one that moderately softens and flows during (heat) pressing is preferable.

<Polyurethane resin>
The method for synthesizing the polyurentane resin is not particularly limited, but for example, the polyol compound (a) and the diisocyanate (b) may be reacted, or the polyol compound (a), the diisocyanate (b) and the diol compound (c) having a carboxyl group may be reacted. To obtain a urethane prepolymer (d) having an isocyanate group, to further react the urethane prepolymer (d) with the polyamino compound (e), or to react as necessary in the above three cases. Examples thereof include those obtained by reacting a stop agent.

As the polyol compound (a), various polyether polyols, polyester polyols, polycarbonate polyols, polybutadiene glycols, or a mixture thereof, which are generally known as polyol components constituting the polyurethane resin, can be used.

Examples of the polyether polyols include polymers or copolymers of ethylene oxide, propylene oxide, tetrahydrofuran and the like.
Examples of polyester polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1, Saturated and unsaturated low molecular weight diols such as 5-pentanediol, hexanediol, octanediol, 1,4-butylenediol, diethyleneglycol, triethyleneglycol, dipropyleneglycol, dimerdiol, and n-butylglycidyl ether, 2 -Alkyl glycidyl ethers of ethylhexyl glycidyl ethers, monocarboxylic acid glycidyl esters such as versatic acid glycidyl esters, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, Dicarboxylic acids such as malonic acid, glutaric acid, pimelli acid, suberic acid, adipic acid, and sebacic acid, or anhydrides thereof are dehydrated and condensed to obtain polyester polyols or cyclic ester compounds. Examples thereof include the obtained polyester polyols.
As the polycarbonate polyols, 1) a reaction product of diol or bisphenol and carbonic acid ester, and 2) a reaction product of diol or bisphenol with phosgene in the presence of alkali can be used. Examples of the carbonic acid ester include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, propylene carbonate and the like. The diols include ethylene glycol, propylene glycol, dipropylene glycol, diethylene glycol, triethylene glycol, butylene glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 3,3. '-Dimethylol heptane, polyoxyethylene glycol, polyoxypropylene glycol, propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9 -Nonandiol, neopentyl glycol, octanediol, butylethylpentanediol, 2-ethyl-1,3-hexanediol, cyclohexanediol, 3,9-bis (1,1-dimethyl-2-hydroxyethyl, 2,2) , 8,10-Tetraoxospiro [5.5]
Undecane and the like can be mentioned. Examples of bisphenol include bisphenol A, bisphenol F, and bisphenols obtained by adding alkylene oxides such as ethylene oxide and propylene oxide to bisphenols.

The number average molecular weight (Mn) of the polyol compound is appropriately determined in consideration of the solubility of the polyurethane resin in producing the conductive composition, the durability of the conductive film formed, the adhesive strength to the substrate, and the like. However, it is usually preferably in the range of 580 to 8000, and more preferably 1000 to 5000.
The above polyol compound may be used alone or in combination of two or more. Further, as long as the performance of the polyurethane resin is not lost, a part of the polyol compound can be replaced with small molecule diols, for example, various small molecule diols used for producing the polyol compound.

As the diisocyanate compound (b), aromatic diisocyanate, aliphatic diisocyanate, alicyclic isocyanate, or a mixture thereof can be used, but isophorone diisocyanate is particularly preferable. Examples of the aromatic diisocyanate include 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-benzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, and 1, , 3-Phenylene diisocyanate, 1,4-Phenylene diisocyanate, Tolylene diisocyanate, Xylylene diisocyanate and the like.

Examples of the aliphatic diisocyanate include butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate.
Examples of the alicyclic diisocyanate include cyclohexane-1,4-diisocyanate, isophorone diisocyanate, norbornane diisocyanatomethyl, bis (4-isocyanatecyclohexyl) methane, 1,3-bis (isocyanatemethyl) cyclohexane, and methylcyclohexanediisocyanate. Be done.

Examples of the diol compound (c) having a carboxyl group include dimethylol acetic acid, dimethylol propionic acid, dimethylol butanoic acid, dimethylol alkanoic acid such as dimethylol pentanoic acid, dihydroxysuccinic acid and dihydroxybenzoic acid. In particular, dimethylol propionic acid and dimethylol butanoic acid are preferable from the viewpoint of reactivity and solubility.
The conditions for reacting the polyol compound (a) with the diisocyanate (b) and the diol compound (c) having a carboxyl group to obtain the urethane prepolymer (d) having an isocyanate group are other than making the isocyanate group excessive. Although not particularly limited, the isocyanate group / hydroxyl group equivalent ratio is preferably in the range of 1.05 / 1 to 3/1. More preferably, it is 1.2 / 1 to 2/1. The reaction is usually carried out between room temperature and 150 ° C., and is preferably carried out between 60 and 120 ° C. in terms of production time and control of side reactions.

The polyamino compound (e) acts as a chain extender, and includes ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, norbornandiamine, and 2 -Amines having hydroxyl groups such as (2-aminoethylamino) ethanol, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, and di-2-hydroxypropylethylenediamine can also be used. can. Among them, isophorone diamine is preferably used.

When synthesizing a polyurethane resin by reacting a urethane prepolymer (d) having an isocyanate group with a polyamino compound (e), a reaction terminator can be used in combination in order to adjust the molecular weight of the obtained polyurethane resin. As the reaction terminator, dialkylamines such as di-n-butylamine, dialkanolamines such as diethanolamine, and alcohols such as ethanol and isopropyl alcohol can be used.

The conditions for reacting the urethane prepolymer (d) having an isocyanate group with the polyamino compound (e) and, if necessary, a reaction terminator are not particularly limited, but the free isocyanates at both ends of the urethane prepolymer are not particularly limited. When the number of groups is 1 equivalent, the total equivalent of the polyamino compound (e) and the amino groups in the reaction terminator is preferably in the range of 0.5 to 1.3. More preferably, it is in the range of 0.8 to 0.995.
The weight average molecular weight of the polyurethane resin is preferably in the range of 5000 to 200,000 from the viewpoint of coatability and handleability.

When synthesizing a polyurethane resin, one or two selected from ester-based solvents, ketone-based solvents, glycol ether-based solvents, aliphatic solvents, aromatic solvents, alcohol-based solvents, carbonate-based solvents, water, etc. The above can be used in combination.
Examples of the ester solvent include ethyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, amyl acetate, ethyl lactate and the like.
Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone benzene, diisobutyl ketone, diacetone alcohol, isophorone, cyclohexanenone and the like.
Examples of the glycol ether-based solvent include ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, and acetates of these monoethers, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, and propylene. Examples thereof include glycol monomethyl ethers, propylene glycol monoethyl ethers, and acetates of these monoethers.
Examples of the aliphatic solvent include n-heptane, n-hexane, cyclohexane, methylcyclohexane, ethylcyclohexane and the like.
Examples of the aromatic solvent include toluene, xylene and the like.
Examples of the alcohol solvent include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, cyclohexanol and the like.
Examples of the carbonate solvent include dimethyl carbonate, ethylmethyl carbonate, di-n-butyl carbonate and the like.

<Polyamide resin>
As the binder resin, a polyamide resin is preferable from the viewpoint of volume resistivity and adhesion to the substrate. The volume resistivity is a good result because the resin component in the (heat) press tends to flow.
The polyamide resin used in the present invention is basically a general term for polymers having an amide bond obtained by various reactions such as polycondensation of dibasic acid and diamine, polycondensation of aminocarboxylic acid, or ring-opening polymerization of lactam. This is a mixture of various modified polyamides, products manufactured with a partially hydrogenated reactant, products with a partial copolymerization of other monomers, or other substances such as various additives. It is a broad concept including things.

The polyamide resin used in the present invention is not particularly limited as long as the above conditions are satisfied, but a dimer acid-modified polyamide resin obtained by condensation polymerization of a dibasic acid containing dimer acid as a main component and polyamines is preferable. .. Dimer acid As the dimer acid for producing the modified polyamide resin, dimer acid obtained by polymerizing natural monobasic unsaturated fatty acids contained in tall oil fatty acid, soybean oil fatty acid, etc. is widely used industrially, but in principle. May be various dicarboxylic acids such as saturated fatty acid, unsaturated fatty acid, alicyclic, or aromatic.
Examples of commercially available products of the dimer acid include Hari Dimer 200, 300 (manufactured by Harima Chemicals, Inc.), Versa Dime 228, 216, Empole 1018, 1019, 1061, 1062 (manufactured by Cognis Co., Ltd.) and the like. Further, hydrogenated dimer acid can also be used, and examples of commercially available hydrogenated dimer acid include Prepole 1009 (manufactured by Croda Japan Co., Ltd.) and Empole 1008 (manufactured by Cognis Co., Ltd.).
In addition to the dimer acid, various dicarboxylic acids can be used as the dibasic acid in order to obtain a polyamide resin having appropriate flexibility. Specific examples of the dicarboxylic acid include oxalic acid, malonic acid, (anhydrous) succinic acid, (anhydrous) maleic acid, glutaric acid, adipic acid, bimeric acid, suberic acid, azelaic acid, sebacic acid, terephthalic acid, and isophthalic acid. Acids, phthalic acids, naphthalenedicarboxylic acids, 1,3- or 1,4-cyclohexanedicarboxylic acids, 1,18-octadecanedicarboxylic acids, 1,16-hexadecanedicarboxylic acids and the like are used.

Further, a dibasic acid having a phenolic hydroxyl group can also be used. By using a dibasic acid having a phenolic hydroxyl group, the phenolic hydroxyl group can be introduced into the side chain of the polyamide resin and can be used for the reaction with the curing agent.
Examples of the dibasic acid having a phenolic hydroxyl group include hydroxyisophthalic acid such as 2-hydroxyisophthalic acid, 4-hydroxyisophthalic acid and 5-hydroxyisophthalic acid, 2,5-dihydroxyisophthalic acid and 2,4-dihydroxyisophthalic acid. Dihydroxyisophthalic acid such as 4,6-dihydroxyisophthalic acid, 2-hydroxyterephthalic acid, 2,3-dihydroxyterephthalic acid, dihydroxyterephthalic acid such as 2,6-dihydroxyterephthalic acid, 4-hydroxyphthalic acid, 3-hydroxyphthalic acid Examples thereof include hydroxyphthalic acid such as acid, dihydroxyphthalic acid such as 3,4-dihydroxyphthalic acid, 3,5-dihydroxyphthalic acid, 4,5-dihydroxyphthalic acid and 3,6-dihydroxyphthalic acid.
Further, these acid anhydrides and ester derivatives such as polybasic acid methyl ester can also be mentioned.
Of these, 5-hydroxyisophthalic acid is preferable from the viewpoint of copolymerizability and easy availability.

Further, various monocarboxylic acids are used as needed in order to obtain a polyamide resin having appropriate fluidity when heated. Specifically, as the monocarboxylic acid, propionic acid, acetic acid, caprylic acid (octanoic acid), stearic acid, oleic acid and the like are used.
The polyamines as a reaction product in producing the dimer acid-modified polyamide resin are, for example, various diamines such as aliphatic, alicyclic and aromatic, triamine and polyamine. Specific examples of the above diamines include ethylenediamine, propanediamine, butanediamine, triethylenediamine, tetraethylenediamine, hexamethylenediamine, p- or m-xylene diamine, 4,4'-methylenebis (cyclohexylamine), and 2,2-bis. -(4-Cyclohexylamine), polyglycoldiamine, isophoronediamine, 1,2-, 1,3- or 1,4-cyclohexanediamine, 1,4-bis- (2'-aminoethyl) benzene, N-ethyl Amino piperazine, piperazine and the like can be mentioned.
Further, examples of the triamine include diethylenetriamine, and examples of the polyamine include triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine. Further, a dimer diamine obtained by converting a dimerized aliphatic nitrile group and reducing it with hydrogen can also be used.

Examples of the polyamine compound include a compound obtained by converting a carbosyl group of a polybasic acid compound having a cyclic or acyclic hydrocarbon group having 20 to 48 carbon atoms into an amino group, and examples of commercially available products include croaders. Examples thereof include "Priamine 1071", "Priamine 1073", "Priamine 1074" and "Priamine 1075" manufactured by Japan Co., Ltd. and "Versamine 551" manufactured by Cognis Japan Co., Ltd.
Alkanolamine may be used in combination with the diamine. Examples of alkanolamines include ethanolamine, propanolamine, diethanolamine, butanolamine, 2-amino-2-methyl-1-propanol, 2- (2-aminoethoxy) ethanol and the like. Further, a polyether diamine having oxygen in its skeleton can be used. This polyether has the general formula H ₂ N-R _1- (RO) _n -R ₂ -NH ₂ (in the formula, n is 2 to 100, and R ₁ and R ₂ have 1 to 14 carbon atoms. It is an alkyl group or an alicyclic hydrocarbon group, and R has 1 to 1 to carbon atoms.
It is an alkyl group or an alicyclic hydrocarbon group having 10 elements. The alkyl group may be linear or branched. ) Can be expressed. Examples of this ether diamine include polyoxypropylene diamine and the like, and commercial products include Jeffamines (manufactured by San Techno Chemical Co., Ltd.). Further, bis- (3-aminopropyl) -polytetrahydrofuran can also be mentioned.
The polyamines and dimer acid or various dicarboxylic acids are heat-condensed by a conventional method, and various polyamide resins including dimer acid-modified polyamide resin are produced by an amidation step accompanied by dehydration. Generally, the reaction temperature is about 100 to 300 ° C., and the reaction time is about 1 to 8 hours.

<Polyester resin>
As the binder resin, a polyester resin is preferable from the viewpoint of volume resistivity and adhesion to the substrate. The volume resistivity is a good result because the resin component in the (heat) press tends to flow.
The polyester resin is a polymer composed of a polyvalent carboxylic acid and a polyhydric alcohol as a monomer. As the polyester resin, known ones can be adopted, and specifically, from the viewpoint of ensuring the cohesive force of the resin, the weight average molecular weight is preferably 1000 to 100,000. Further, from the viewpoint of adhesion, the glass transition temperature is preferably −10 ° C. to 200 ° C.
Examples of the polyvalent carboxylic acid component constituting the polyester resin include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, unsaturated dicarboxylic acids, trivalent or higher carboxylic acids, and one or two of these. The above can be selected and used. On the other hand, examples of the polyhydric alcohol component constituting the polyester resin include aliphatic glycols, ether glycols, and trihydric or higher polyalcohols, and one or more of these can be selected and used.
Commercially available polyester resins include Byron (manufactured by Toyobo Co., Ltd., "Byron" is a registered trademark), Polyester (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Polyester" is a registered trademark), and Tesslac (manufactured by Hitachi Chemical Polymer Co., Ltd.). , "Teslac" is a registered trademark).

The binder resin has at least one structure selected from polyether, polyester, polycarbonate, or polybutadiene having a functional group capable of reacting with an isocyanate group from the viewpoint of volume resistance, adhesion to a substrate, and durability. It is also preferable to contain a vinyl-based polymer (A1) having the above in the side chain. The volume resistivity is a good result because the resin component in the (heat) press tends to flow.

(Polymer (A1))
The polymer (A1) is a polyester having a functional group capable of reacting with an isocyanate group in the main chain of a vinyl-based copolymer obtained by polymerizing a monomer having an ethylenically unsaturated double bond. A polyether, polyester, polycarbonate, or polybutadiene graft vinyl-based polymer having at least one structure selected from polyester, polyester, or polybutadiene introduced as a side chain.

Examples of the functional group capable of reacting with the isocyanate group include a hydroxyl group, an amino group, a carboxyl group, an epoxy group, an N-methylol group, an N-alkoxymethyl group and the like, and a hydroxyl group is preferable in terms of reactivity.
The method for introducing the side chain is not particularly limited, but for example, a copolymer (f) of an unsaturated dibasic acid and another monomer having an ethylenically unsaturated double bond is synthesized. It is selected from polyether, polyester, polycarbonate, or polybutadiene having a carboxylic acid or anhydrous carboxylic acid moiety of the copolymer (f), a functional group capable of reacting with a carboxyl group, and a functional group capable of reacting with an isocyanate group. It can be introduced by subjecting at least one (g) carboxyl group and a reactive functional group to a condensation reaction.
In addition, when used in applications that require higher toughness and durability, it is possible to introduce a functional group capable of reacting with isocyanate directly into the main chain of the vinyl-based polymer in order to obtain a higher crosslink density. desirable. In that case, the polymer (A1) is an unsaturated dibasic acid (f1), a monomer (f2) other than (f1) having a functional group capable of reacting with isocyanate and an ethylenically unsaturated double bond, and ethylene. A copolymer (f) of a monomer (f3) other than (f1) and (f2) having a sex-unsaturated double bond, a functional group capable of reacting with a carboxyl group, and a functional group capable of reacting with an isocyanate group. It can be obtained by a condensation reaction with at least one (g) selected from a polyether, a polyester, a polycarbonate, or a polybutadiene having the above.
Examples of unsaturated dibasic acids (f1) that can be used to synthesize the copolymer (f) are maleic acid, maleic anhydride, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, crotonic acid, diphenylmethane-di. -Γ-Ketocrotonic acid and the like can be mentioned.
The unsaturated dibasic acid (f1) can be used alone or in combination of two or more depending on the required performance. The proportion of the unsaturated dibasic acid (f1) in the monomer that is the raw material of the copolymer (f) is preferably 0.01 to 30% by weight, more preferably 0.05 to 10% by weight. be.
Examples of the monomer (f2) other than (f1) having a functional group capable of reacting with isocyanate and an ethylenically unsaturated double bond include a (meth) acrylic monomer having a functional group capable of reacting with an isocyanate group. Vinyl monomers and the like can be used. Of these, (meth) acrylic monomers are preferable in terms of reactivity.
Examples of the functional group capable of reacting with the isocyanate group include a hydroxyl group, an amino group, a carboxyl group, an epoxy group, an N-methylol group, an N-alkoxymethyl group and the like, and a hydroxyl group is preferable in terms of reactivity.

Examples of the (meth) acrylic monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 1-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. Examples thereof include polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, and polytetramethylene glycol mono (meth) acrylate.
Examples of the (meth) acrylic monomer having an amino group include methylaminoethyl (meth) acrylate, ethylaminoethyl (meth) acrylate, butylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate. N, N-dialkylamino such as monoalkylaminoalkyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylamino (meth) acrylate, N, N-dibutylaminoethyl (meth) acrylate Alkyl (meth) acrylate and the like can be mentioned.
Examples of the (meth) acrylic monomer having a carboxyl group include acrylic acid and methacrylic acid.
Examples of the (meth) acrylic monomer having an epoxy group include glycidyl (meth) acrylate.
Examples of the (meth) acrylic monomer having an N-methylol group include N-methylol (meth) acrylamide and the like.
Examples of the (meth) acrylic monomer having an N-alkoxymethyl group include N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, N-propoxymethyl (meth) acrylamide, and N-butoxymethyl ( (Meta) acrylamide having N-monoalkoxymethyl group such as meta) acrylamide, N, N-dimethylol (meth) acrylamide, N, N-di (methoxymethyl) (meth) acrylamide, N, N-di (ethoxymethyl) ) (Meta) acrylamide, N, N-di (propoxymethyl) (meth) acrylamide, N, N-di (butoxymethyl) (meth) acrylamide, etc. (meth) acrylamide having N, N-dialkoxymethyl groups, etc. Can be mentioned.

Examples of the vinyl monomer include hydroxystyrene and vinyl alcohol.
The monomer (f2) other than (f1) having a functional group capable of reacting with isocyanate and an ethylenically unsaturated double bond may be used alone or in combination of two or more depending on the required performance. can. The proportion of the monomer (f2) in the monomer that is the raw material of the copolymer (f) is preferably 0.01 to 50% by weight, more preferably 0.1 to 20% by weight, and particularly preferably. Is 0.1 to 10% by weight.

Examples of the monomer (f3) other than (f1) and (f2) having an ethylenically unsaturated double bond include a (meth) acrylic monomer, an aromatic vinyl monomer, and an olefin hydrocarbon monomer. , Vinyl ether monomer and the like can be used.
Examples of the (meth) acrylic monomer include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and stearyl (meth) acrylate. Examples thereof include alkyl (meth) acrylate and benzyl (meth) acrylate.
Examples of the aromatic vinyl monomer include styrene, methylstyrene, ethylstyrene and the like.
Examples of the olefin hydrocarbon monomer include ethylene, propylene, butadiene, isobutylene, isoprene, 1,4-pentadiene and the like.
Examples of vinyl ether monomers include vinyl methyl ether.
The monomers other than (f1) and (f2) having an ethylenically unsaturated double bond can be used alone or in admixture of two or more depending on the required performance.

The copolymer (f) can be obtained by a known method, for example, solution polymerization. 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. 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. Two or more kinds of solvents may be mixed and used.
The concentration of the monomer charged at the time of synthesis is preferably 0 to 80% by weight.
Examples of the polymerization initiator include peroxides or azo compounds such as benzoyl peroxide, azoisobutylvaleronitrile, azobisisobutyronitrile, dit-butyl peroxide, t-butylperbenzoate, and t-butylperoctate. Kumen hydroxyperoxide and the like can be used, and the polymerization temperature is preferably 50 to 200 ° C, particularly preferably 70 to 140 ° C.

The polystyrene-equivalent weight average molecular weight of the copolymer (f) is preferably 5,000 to 500,000, more preferably 10,000 to 100,000.

Examples of the compound (g) include a polyether and a polyester having one or more functional groups capable of reacting with a carboxyl group and one or more functional groups capable of reacting with an isocyanate group at a linear end or a branched end. Polyester or polybutadiene can be used. Above all, polyester is preferable in order to obtain sufficient coating film strength after hot pressing.
Examples of the functional group capable of reacting with the carboxyl group of the compound (g) include a hydroxyl group, an epoxy group, an amino group, an isocyanate group and the like, and a hydroxyl group is preferable in terms of reactivity. Examples of the functional group capable of reacting with the isocyanate group of the compound (g) include a hydroxyl group, an amino group, a carboxyl group, an epoxy group, an N-methylol group, an N-alkoxymethyl group and the like, but in terms of reactivity. A hydroxyl group is suitable. The functional group capable of reacting with the carboxyl group of the compound (g) and the functional group capable of reacting with the isocyanate group may be the same functional group or different functional groups.

Examples of the polyester include a terminal hydroxyl group-containing ester compound obtained by esterifying at least one dicarboxylic acid and at least one polyol such as a polyhydric alcohol, a polyhydric phenol, or an alkoxy-modified product thereof, and a terminal. Examples thereof include an ester compound obtained by modifying the hydroxyl group of the above to an amino group, a carboxyl group, an epoxy group, an N-methylol group, or an N-alkoxymethyl group.
Examples of dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalic acid, p-oxybenzoic acid, p- (hydroxy) benzoic acid, 1,4-cyclohexanedicarboxylic acid, succinic acid, adipic acid. , Dicarboxylic acids such as azelaic acid, sebacic acid and dodecanedicarboxylic acid.
Examples of polyhydric alcohols are 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 2-methyl-1,4-butanediol, 1,2-dimethyl-. 1,4-Butanediol, 2-ethyl-1,4-butanediol, 1,5-pentanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,2 , 4-trimethyl-1,3-pentanediol, 3-ethyl-1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,6-hexanediol, 3-methyl-1,6-hexane Glycol, 1,7-heptanediol, 2-methyl-1,7-heptanediol, 3-methyl-1,7-heptanediol, 4-methyl-1,7-heptanediol, 1,8-octanediol, 2 -Methyl-1,8-octanediol, 2-ethyl-1,8-octanediol, 3-methyl-1,8-octanediol, 4-methyl-1,8-octanediol, 1,9-nonanediol, Ethylene Glycol, Propylene Glycol, Neopentyl Glycol, Diethylene Glycol, Dipropylene Glycol, Cyclohexanedimethanol, Polyethylene Glycol, Polypropylene Glycol, Polytetramethylene Glycol, Trimethylol Propane, 1,1,1-Trimethylol Propane Ethylene Glycol, Glycerin, Erythritol , Xylitol, sorbitol, mannitol and the like.
Examples of the polyvalent phenol include catechol, resorcin, hydroquinone, hexylresorcin, trihydroxybenzene, dimethylolphenol and the like.
Examples of commercially available polyesters (polyester polyols) having two or more hydroxyl groups include Kuraray polyols P-510, P-1010, P-1510, P-2010, P-3010, and P-4010 manufactured by Kuraray Co., Ltd. P-5010, P-6010, P-2011, P-2013, P-520, P-1020, P-2020, P-1012, P-2012, P-530, P-1030, P-2030, PMHC- 2050, PMHC-2050R, PMHC-2070, PMHC-2090, PMSA-1000, PMSA-2000, PMSA-3000, PMSA-4000, F-2010, F-3010, N-2010, PNOA-1010, PNOA-2014, O-2010, Desmophen 650MPA, 651MPA / X, 670, 670BA, 680X, 680MPA, 800, 800MPA, 850, 1100, 1140, 1145, 1150, 1155, 1200, 1300X, 1652, 1700, manufactured by Sumitomo Bayer Urethane Co., Ltd. Examples thereof include 1800, RD181, RD181X, C200, Byron 200, 560, 600, GK130, GK860, GK870, 290, GK590, GK780, GK790 manufactured by Toyo Spinning Co., Ltd.
Examples of the polyether include polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol, and terminal hydroxyl groups such as amino group, carboxyl group, epoxy group, N-methylol group or N-alkoxymethyl group. Examples include modified ether compounds. Examples of commercially available polyethers having two or more hydroxyl groups (polyether polyols) include Desmophen 250U, 550U, 1600U, 1900U, 1915U, 1920D manufactured by Sumitomo Bayer Urethane Co., Ltd.

Examples of the polycarbonate include a polycarbonate diol represented by the following general formula, and a carbonate compound in which the terminal hydroxyl group is modified to an amino group, a carboxyl group, an epoxy group, an N-methylol group or an N-alkoxymethyl group. ..
H- (OR-OCO-) nR-OH
(R: alkylene chain, diethylene glycol, etc.)
Examples of commercially available polycarbonates having two or more hydroxyl groups include Kuraray polyols PNOC-1000, PNOC-2000, PMHC-2050, PMHC-2050R, PMHC-2070, PMHC-2070R, PMHC-2090R, C manufactured by Kuraray Co., Ltd. -2090 and the like can be mentioned.
Examples of polybutadiene include α, ω-polybutadiene glycol, α, β-polybutadiene glycol, and butadiene in which the terminal hydroxyl group is modified to an amino group, a carboxyl group, an epoxy group, an N-methylol group or an N-alkoxymethyl group. Examples include compounds.
Examples of commercially available polybutadiene having two or more hydroxyl groups include NISSO-PBG-1000, G-2000, G-3000, GI-1000, GI-2000, GI-3000, and GQ-1000 manufactured by Nippon Soda Corporation. GQ-2000 and the like can be mentioned.
Examples of commercially available polybutadiene having two or more epoxy groups include NISSO-PBBF-1000, EPB-13, and EPB-1054 manufactured by Nippon Soda Corporation.

The polystyrene-equivalent weight average molecular weight of compound (g) is preferably 500 to 25,000, more preferably 1,000 to 10,000. When the weight average molecular weight of the compound (g) is 25,000 or less, the solubility in a solvent, the compatibility with the copolymer (f), the reactivity with the copolymer (f) are excellent, and the heat Sufficient coating strength can be obtained after pressing. Further, in the case of 500 or more, sufficient flexibility can be imparted to the sheet, and the adhesion with the base material is improved.

The polymer (A1) comprises a carboxylic acid or anhydrous carboxylic acid moiety of the copolymer (f) and a functional group capable of reacting with the carboxyl group of the compound (g) by a known method, for example, the compound (g). The functional group capable of reacting with the carboxyl group can be obtained by hydroxylation, esterification in the case of an epoxy group, amidation in the case of an amino group, and imidization in the case of an isocyanate group. As the solvent, the solvent at the time of synthesizing the copolymer (f) can be used as it is, and further, another solvent may be added or the solvent may be removed depending on the conditions at the time of synthesis, the conditions at the time of coating and the like. It doesn't matter.
As the reaction catalyst, for example, tertiary amines such as triethylamine, triethanolamine, and ethylenediamine are used, and the reaction temperature is preferably 50 to 300 ° C.
The reaction ratio between the copolymer (f) and the compound (g) is such that 1 mol of the carboxylic acid or the anhydrous carboxylic acid of the copolymer (f) has a functional group capable of reacting with the carboxyl group of the compound (g). , 0.01 to 10 mol, more preferably 0.1 to 5 mol, still more preferably 0.5 to 2 mol.
Further, it is not necessary to use one type each of the copolymer (f) and the compound (g), and a plurality of types may be used depending on the purpose and required physical properties.
The polystyrene-equivalent weight average molecular weight of the polymer (A1) is preferably 5,000 to 500,000, more preferably 10,000 to 100,000. When the weight average molecular weight of the polymer (A1) is 500,000 or less, the solubility in a solvent is improved, and when it is 5,000 or more, sufficient coating film strength is obtained after (heat) pressing. ..

(Polyisocyanate compound (D))
When the binder resin is a vinyl-based polymer (A1) having at least one structure selected from polyether, polyester, polycarbonate, or polybutadiene having a functional group capable of reacting with an isocyanate group on the side chain, Further, it is preferable to contain a polyisocyanate compound (D) having two or more isocyanate groups.
A polyisocyanate compound having two or more isocyanate groups is used to crosslink the polymer (A1) and the polymer (A1) to obtain sufficient coating film strength after hot pressing.
As the polyisocyanate compound, when used outdoors, it is preferable to use only an alicyclic or aliphatic compound in order to prevent the coating film from deteriorating over time.
Examples of the alicyclic polyisocyanate compound include isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated 4,4'-diphenylmethane diisocyanate and the like.
Examples of the aliphatic polyisocyanate compound include trimethylhexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate.
Examples of the aromatic polyisocyanate compound include diphenylmethane diisocyanate, toluylene diisocyanate, naphthylene-1,5-diisocyanate, o-xylene diisocyanate, m-xylene diisocyanate, p-xylene diisocyanate, triphenylmethane triisocyanate, and polymethylene polyphenyl. Examples include isocyanate.
As the polyisocyanate compound, a bi-terminal isocyanate adduct, a biuret-modified product, or an isocyanurate-modified product of the above compound and glycols or diamines may be used.
In particular, when the polyisocyanate compound contains an isocyanurate modified product, particularly an isocyanurate ring-containing triisocyanate, sufficient coating film strength can be obtained after hot pressing, which is preferable. Specific examples of the isocyanurate ring-containing triisocyanate include isocyanurate-modified isophorone diisocyanate (for example, Death Module Z4470 manufactured by Sumitomo Bayer Urethane Co., Ltd.) and isocyanurate-modified hexamethylene diisocyanate (for example, Sumijur manufactured by Sumitomo Bayer Urethane Co., Ltd.). N3300), isocyanurate-modified tolylene diisocyanate (for example, Sumijour FL-2, FL-3, FL-4, HLBA manufactured by Sumitomo Bayer Urethane Co., Ltd.).

Further, the isocyanate group of the polyisocyanate compound may be, for example, methanol, ethanol, n-pentanol, ethylene chlorhydrin, isopropyl alcohol, phenol, p-nitrophenol, m-cresol, acetylacetone, ethyl acetoacetate, ε-caprolactam. A block-modified product that has been blocked by reacting with a blocking agent such as the above may be used.
Further, as the polyisocyanate compound, at least one selected from polyether, polyester, polycarbonate, or polybutadiene having two or more functional groups capable of reacting with an isocyanate group (h) and a diisocyanate compound having isocyanate groups at both ends (i). ) And a double-ended isocyanate prepolymer may be used.
When the polyisocyanate compound contains the above-mentioned two-terminal isocyanate prepolymer, flexibility can be obtained with a small amount, and the adhesion to the substrate is improved.
As the compound (h), the same compound as the compound (g) can be used. Compound (i
), For example, toluene diisocyanate, naphthylene-1,5-diisocyanate, o-toluene diisocyanate, diphenylmethane diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, m-xylene. Examples thereof include diisocyanate, p-xylene diisocyanate, lysine diisocyanate, hydrogenated 4,4'-diphenylmethane diisocyanate, and hydrogenated tolylene diisocyanate.
The two-terminal isocyanate prepolymer is a compound (h) and a compound (h) at a ratio such that the isocyanate group of the compound (i) is larger than 1 mol with respect to 1 mol of the functional group capable of reacting with the isocyanate group of the compound (h). It is obtained by mixing i), heating and stirring to react. The polystyrene-equivalent weight average molecular weight of the prepolymer is preferably 500 to 50,000, more preferably 1,000 to 50,000, and particularly preferably 1,000 to 10,000.
The total number of isocyanate groups of the polyisocyanate compound (D) is preferably 0.1 to 5.0 times, more preferably 0, with respect to the total number of functional groups of the polymer (A1), depending on the required performance. One kind or a mixture of two or more kinds can be used at a ratio of 5.5 times to 3.0 times, particularly preferably 0.8 to 2.0 times.

Next, the carbon material (B) will be described.

The conductive carbon material (B) in the conductive composition of the present invention is characterized by containing graphite (B-1) and a carbon material (B-2) other than graphite.
The mass ratio of the binder resin (A) to the carbon material (B) is preferably 15:85 to 35:65, preferably 20:80 to 30:70.

When the mass ratio of the binder resin is less than 15, the adhesion of the conductive film is lowered and the adhesion is poor. On the other hand, when the mass ratio of the binder resin exceeds 35, the contact between the carbon materials in the conductive film is hindered, and the conductivity becomes poor.

When the mass ratio of the binder resin is 20 to 30, adhesion can be exhibited without inhibiting the formation of the conductive network in the conductive film formed by the conductive composition.

As the graphite (B-1), for example, artificial graphite, natural graphite, or the like can be used. Artificial graphite is made by artificially orienting irregularly arranged micrographite crystals by heat treatment of amorphous carbon, and is generally manufactured using petroleum coke or coal-based pitch coke as the main raw material. To. As the natural graphite, scaly graphite, lump graphite, earth graphite and the like can be used. It is also possible to use expanded graphite (also referred to as expandable graphite) obtained by chemically treating scaly graphite, or expanded graphite obtained by heat treatment and expansion of expanded graphite and then miniaturization or pressing. You can. Among these graphites, when used for a conductive film of a wiring sheet, scaly graphite expanded graphite and flaky graphite such as flaky graphite are preferable from the viewpoint of conductivity.

The surface of these graphites is subjected to surface treatments such as epoxy treatment, urethane treatment, silane coupling treatment, oxidation treatment and the like in order to increase the affinity with the binder resin as long as the characteristics of the conductive composition of the present invention are not impaired. May be applied.

The average particle size of the graphite used is preferably 2 to 100 μm, and particularly preferably 20 to 50 μm.

If the average particle size of graphite is less than 2 μm, the aspect ratio of the graphite particles is lowered, and the contact between the graphite particles tends to be point contact, so that a conductive network cannot be sufficiently formed. On the other hand, when the average particle size of graphite is 100 μm or more, the voids between the graphite particles become large, and the proportion of conductive paths formed between carbon materials other than graphite in the conductive network increases, causing a decrease in conductivity.

The average particle size referred to in the present invention is a particle size (D50) that becomes 50% when the volume ratio of the particles is integrated from the fine particle size distribution in the volume particle size distribution, and is generally used. It is measured with a standard particle size distribution meter, for example, a dynamic light scattering type particle size distribution meter (“Microtrack UPA” manufactured by Nikkiso Co., Ltd.).

As commercially available graphite, for example, as flaky graphite, CMX, UP-5, UP-10, UP-20, UP-35N, CSSP, CSPE, CSP, CP, CB-150, CB manufactured by Nippon Graphite Industry Co., Ltd. -100, ACP, ACP-100, ACB-50, ACB-100, ACB-150, SP-10, SP-20, J-SP, SP-270, HOP, GR-60, LEP, F # 1, F # 2, F # 3, CX-3000, FBF, BF, CBR, SSC-3000, SSC-600, SSC-3, SSC, CX-600, CPF-8, CPF-3, CPB- made by Chuetsu Graphite Co., Ltd. 6S, CPB, 96E, 96L, 96L-3, 90L-3, CPC, S-87, K-3, CF-80, CF-48, CF-32, CP-150, CP-100, CP, HF- 80, HF-48, HF-32, SC-120, SC-80, SC-60, SC-32, EC1500, EC1000, EC500, EC300, EC100, EC50 manufactured by Ito Graphite Industry Co., Ltd. 10099M manufactured by Nishimura Graphite Co., Ltd. , PB-99 and the like. Examples of the spherical natural graphite include CGC-20, CGC-50, CGB-20, and CGB-50 manufactured by Nippon Graphite Industry Co., Ltd. Examples of earth-like graphite include blue P, AP, AOP, P # 1 manufactured by Nippon Graphite Industry Co., Ltd., and APR, S-3, AP-6, 300F manufactured by Chuetsu Graphite Co., Ltd. As artificial graphite, PAG-60, PAG-80, PAG-120, PAG-5, HAG-10W, HAG-150 manufactured by Nippon Graphite Industry Co., Ltd., RA-3000, RA-15, RA- of Chuetsu Graphite Co., Ltd. 44, GX-600, G-6S, G-3, G-150, G-100, G-48, G-30, G-50, SGP-100, SGP-50, SGP-25 manufactured by SEC Carbon Co., Ltd. , SGP-15, SGP-5, SGP-1, SGO-100, SGO-50, SGO-25, SGO-15, SGO-5, SGO-1, SGX-100, SGX-50, SGX-25, SGX -15, SGX-5, SGX-1 can be mentioned.

The content of graphite (B-1) in the conductive composition in the present invention is 75 to 99% by mass in 100% by mass of the carbon material (B), and in particular, 100% by mass of the carbon material (B). It is preferably 80 to 99% by mass in%, and more preferably 90 to 97.5% by mass in 100% by mass of the carbon material (B).

When the content of graphite (B-1) is less than 75% by mass in 100% by mass of the carbon material (B), the orientation of the graphite particles is lowered due to the excess amount of the carbon material (B-2) other than graphite. Since most of the conductive network is occupied by carbon materials other than graphite, specific high conductivity is not exhibited. On the other hand, when the graphite content exceeds 99% by mass in 100% by mass of the carbon material (B), the conductivity in the plane direction by the graphite particles becomes dominant, and the conductivity of the conductive film reaches a plateau.

When the content of graphite (B-1) is 80% by mass or more in 100% by mass of the carbon material (B), a good coating film can be formed with few pinholes in the conductive film.

When the content of graphite (B-1) is 90 to 97.5% by mass in 100% by mass of the carbon material (B), in addition to the high conductivity in the plane direction due to the graphite particles, an appropriate amount of graphite other than The carbon material (B-2) of the above can strengthen the conductive network in the vertical direction without impairing the conductivity in the planar direction derived from graphite, and can exhibit very high conductivity.

When the content of graphite (B-1) is less than 90% by mass in 100% by mass of the carbon material (B), a coating film having less unevenness of the conductive film can be obtained.

(Carbon material other than graphite (B-2))
The carbon material other than graphite is not particularly limited, but carbon black is more preferable from the viewpoint of particle size and specific surface area. In addition, conductive carbon fibers (carbon nanotubes, carbon nanofibers, carbon fibers), fullerene and the like can be used alone or in combination of two or more.

Carbon black includes furnace black, which is produced by continuously pyrolyzing gas or liquid raw materials in a reactor, especially acetylene black made from ethylene heavy oil, and the flame is burned by burning the raw material gas to the bottom of the channel steel. Various types such as channel black that has been rapidly cooled and precipitated, thermal black that is obtained by periodically repeating combustion and pyrolysis using gas as a raw material, and acetylene black that uses acetylene gas as a raw material, alone or 2 It can be used in combination with more than one type. In addition, normally oxidized carbon black, hollow carbon, and the like can also be used.

Oxidation treatment of carbon is performed by treating carbon at a high temperature in the air or secondarily treating it with nitric acid, nitrogen dioxide, ozone, etc., for example, phenol group, quinone group, carboxyl group, carbonyl group, etc. It is a process of directly introducing (covalently bonding) an oxygen-containing polar functional group to the carbon surface, and is generally performed to improve the dispersibility of carbon. However, since the conductivity of carbon generally decreases as the amount of the functional group introduced increases, it is preferable to use carbon that has not been oxidized.

As the specific surface area of the carbon black used increases, the contact points between the carbon black particles increase, which is advantageous for lowering the internal resistance of the electrode. Specifically, the specific surface area (BET) obtained from the amount of nitrogen adsorbed is 20 m ² / g or more and 1500 m ² / g or less, preferably 50 m ² / g or more and 1500 m ² / g or less, and more preferably 100 m ² It is desirable to use the one of / g or more and 1500 m ² / g or less. If carbon black having a specific surface area of less than 20 m ² / g is used, it may be difficult to obtain sufficient conductivity, and carbon black having a specific surface area of more than 1500 m ² / g may be difficult to obtain as a commercially available material. be.

The particle size of the carbon black used is preferably 0.005 to 1 μm in primary particle size, and particularly preferably 0.01 to 0.2 μm. However, the primary particle diameter referred to here is an average of the particle diameters measured by an electron microscope or the like.

Examples of commercially available carbon black include Tokai Carbon's Talker Black # 4300, # 4400, # 4500, # 5500, Degussa's Printex L, and Colombian's Raven 7000, 5750, 5250, 5000 ULTRA III, 500.
0ULTRA, ConductexSCULTRA, Conductex975ULTRA, PUERBLACK100, 115, 205, Mitsubishi Chemical # 2350, # 2400B, # 2600B, # 3050B, # 3030B, # 3230B, # 3350B, # 3400B, # 5400B, Cabo 1300, 900, VulcanXC-72R, BlackPearls2000, Denkaco250G, Ensaco260G, Ensaco350G, SuperP-Li, etc. Furness Black manufactured by TIMCAL), EC-300J, EC-600JD, etc. Examples thereof include acetylene black such as Denka Black, Denka Black HS-100, and FX-35 manufactured by Denka Black, but the present invention is not limited to these, and two or more types may be used in combination.

As the conductive carbon fiber, one obtained by firing from a raw material derived from petroleum is preferable, but one obtained by firing from a raw material derived from a plant can also be used. Further, the carbon nanotubes include a single-walled carbon nanotube in which a graphene sheet forms a tube having a diameter in a nanometer region, and a multi-walled carbon nanotube in which the graphene sheet is a multi-walled layer. Therefore, the diameter of the multi-walled carbon nanotube shows a large value of 30 nm with respect to 0.7-2.0 nm of a typical single-walled carbon nanotube.

Examples of commercially available conductive carbon fibers and carbon nanotubes include vapor-phase carbon fibers such as VGCF manufactured by Showa Denko Co., Ltd., EC1.0, EC1.5, EC2.0, EC1.5-P manufactured by Meijo Nanocarbon Co., Ltd., etc. Examples thereof include single-walled carbon nanotubes manufactured by CNano, FloTube9000, FloTube9100, FloTube9110, FloTube9200, NC7000 manufactured by Nanocyl, and 100T manufactured by Knano.

Next, the solvent will be described. When the binder resin (A) in the conductive composition and the conductive carbon material (B) are uniformly mixed, a solvent can be appropriately used. Examples of such a solvent include organic solvents and water.
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 for 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.
In the case of adopting a printing coating method in which a conductive composition such as screen printing is required to have a viscosity of a certain level or higher, the viscosity of the organic solvent at 25 ° C. is preferably 30 mPa · s to 75,000 mPa · s. If it is less than 30 mPa · s, the resin content is low due to high conductivity, so that good dispersibility of the viscous and conductive carbon material suitable for coating cannot be obtained, and the coatability is insufficient. If it exceeds 75,000 mPa · s, the viscosity is too high and the dispersibility of the carbon material is significantly lowered. For example, tarpineol, dihydroterpineol, 2,4-diethyl-1,5-pentanediol, 1,3-butylene glycol, isobornylcyclohexanol can be mentioned. Two or more kinds of high-viscosity solvents shown here may be used, and the viscosity at 25 ° C. such as methyl ethyl ketone, toluene and isopropyl alcohol is 30 mPa · s.
It can also be used in combination with a low viscosity solvent of less than.

Next, other components will be described. The conductive composition of the present invention contains, if necessary, an ultraviolet absorber, an ultraviolet stabilizer, a radical catching agent, a filler, a thixotropic 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, disinfectants, defoamers, leveling agents, anti-blocking agents, hardeners, thickeners, Various additives such as a pigment dispersant and a silane coupling agent may be added.

(Disperser / Mixer)
As an apparatus used for obtaining a conductive composition, a disperser or a mixer usually used for pigment dispersion or the like can be used.

For example, mixers such as disper, homomixer, or planetary mixer; homogenizers such as "Clairemix" manufactured by M-Technique or "Philmix" manufactured by PRIMIX; paint conditioner (manufactured by Red Devil), ball mill, sand mill. Media type disperser such as (Symmal Enterprises "Dyno Mill" etc.), Atreiter, Pearl Mill (Eirich "DCP Mill" etc.), or Coball Mill; Wet Jet Mill (Genus PY "Genus PY", Sugino Medialess disperser such as "Starburst" manufactured by Machine Co., "Nanomizer" manufactured by Nanomizer, "Claire SS-5" manufactured by M-Technique, or "MICROS" manufactured by Nara Machinery; or other roll mills, etc. However, it is not limited to these.

For example, when using a media-type disperser, a method in which the agitator and vessel use a disperser made of ceramic or resin, or a disperser in which the surface of the metal agitator and vessel is treated with tungsten carbide spraying or resin coating. It is preferable to use. As the medium, it is preferable to use glass beads, zirconia beads, or ceramic beads such as alumina beads. As the dispersive device, only one type may be used, or a plurality of types of devices may be used in combination.

(Conducting film)
The conductive film of the present invention has a conductive film formed from a conductive composition on a substrate.

(Sheet-like base material)
The shape of the sheet-like base material used for forming the conductive film is not particularly limited, but an insulating resin film is preferable, and one suitable for various uses can be appropriately selected.

For example, examples of the material include PET (polyethylene terephthalate), PEN (polyethylene naphthalate), polyimide, polyvinyl chloride, polyamide, nylon, OPP (stretched polypropylene), CPP (unstretched polypropylene), and the like, but are particularly limited. There is no such thing.

As the shape, a film on a flat plate is generally used, but a film having a roughened surface, a primer-treated film, a perforated film, and a mesh-like substrate can also be used.

The method for coating the conductive composition on the sheet-like substrate is not particularly limited, and a known method can be used.

Specific examples include a die coating method, a dip coating method, a roll coating method, a doctor coating method, a knife coating method, a spray coating method, a gravure coating method, a screen printing method, an electrostatic coating method, and the like, and drying. As the method, a stand-alone dryer, a blower dryer, a warm air dryer, an infrared heater, a far-infrared heater, and the like can be used, but the method is not particularly limited thereto.

Further, after coating, a rolling process such as a lithographic press or a calendar roll may be performed, or may be performed while heating in order to soften the conductive film and facilitate pressing. The thickness of the conductive film is generally 0.1 μm or more and 1 mm or less, preferably 1 μm or more and 200 μm or less.

(Volume resistivity of conductive film)
The volume resistivity of the conductive film of the present invention is preferably less than 1 × 10 − ² Ω · cm. Since the volume resistivity is less than 1 × 10 ⁻² Ω · cm, it can be suitably used as a battery electrode, a current collector, a battery, wiring of an electronic device, and the like.

Hereinafter, the present invention will be described in more detail by way of examples, but the following examples do not limit the scope of rights of the present invention in any way. In the examples and comparative examples, "parts" represents "parts by mass", Mw means weight average molecular weight, and Tg means glass transition temperature.

<Synthesis of binder resin A-1>
Polyester polyol (manufactured by Kuraray Co., Ltd.) obtained from terephthalic acid, adipic acid and 3-methyl-1,5-pentanediol in a reaction vessel equipped with a stirrer, a thermometer, a reflux cooler, a dropping device, and a nitrogen introduction tube. "Kurare Polyol P-2011", Mn = 2011) 455.5 parts, dimethylol butanoic acid 16.5 parts, isophorone diisocyanate 105.2 parts, and toluene 140 parts were charged and reacted at 90 ° C. for 3 hours under a nitrogen atmosphere. Toluene was added in an amount of 360 parts to obtain a urethane prepolymer solution having an isocyanate group. Next, a urethane prepolymer solution having an isocyanate group obtained by mixing 19.9 parts of isophoronediamine, 0.63 parts of di-n-butylamine, 294.5 parts of 2-propanol, and 335.5 parts of toluene. 969.5 parts were added, and the mixture was reacted at 50 ° C. for 3 hours followed by 70 ° C. for 2 hours, diluted with 126 parts of toluene and 54 parts of 2-propanol, Mw = 61,000, acid value = 10 mgKOH / g, urethane pre. A solution of polyurethane resin A-1 was obtained in which the total equivalent of the polyamino compound and the amino groups in the reaction terminator was 0.98 with respect to the free isocyanate groups at both ends of the polymer.

<Synthesis of binder resin A-2>
In a 4-necked flask equipped with a stirrer, a reflux condenser, a nitrogen introduction tube, an introduction tube, and a thermometer, 156.2 g of prepol 1009 as a polybasic acid compound, 5.5 g of 5-hydroxyisophthalic acid, and preamine as a polyamine compound. 146.4 g of 1074 and 100 g of ion-exchanged water were charged, and the mixture was stirred until the heat generation temperature became constant. When the temperature became stable, the temperature was raised to 110 ° C, and after confirming the outflow of water, the temperature was raised to 120 ° C 30 minutes later, and then the dehydration reaction was continued while raising the temperature by 10 ° C every 30 minutes. .. When the temperature reached 230 ° C., the reaction was continued at the same temperature for 3 hours and kept under a vacuum of about 2 kPa for 1 hour to lower the temperature. Finally, an antioxidant is added, and the weight average molecular weight is 24000, the acid value is 13.2 KOHmg / g, and the hydroxyl value is 5.
.. A polyamide resin A-2 having a glass transition temperature of −32 ° C. and 5 KOH mg / g was obtained.

The resin was evaluated as follows.
<Measurement method of weight average molecular weight (Mw)>
For the measurement of Mw, GPC (gel permeation chromatography) "HPC-8020" manufactured by Tosoh Corporation was used. GPC is a liquid chromatography in which a substance dissolved in a solvent (THF; tetrahydrofuran) is separated and quantified according to the difference in molecular size. In the measurement in the present invention, two "LF-604" (manufactured by Showa Denko KK: GPC column for rapid analysis: 6 mm ID x 150 mm size) are connected in series to the column, the flow rate is 0.6 ml / min, and the column temperature is set. The measurement was performed under the condition of 40 ° C., and the weight average molecular weight (Mw) was determined in terms of polystyrene.
<Measurement of acid value>
Precisely weigh about 1 g of the sample in an Erlenmeyer flask with a stopper, and add 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixture to dissolve the sample. Phenolphthalein test solution is added to this as an indicator and held for 30 seconds. Then, titrate with 0.1N alcoholic potassium hydroxide solution until the solution turns pink. The acid value was calculated by the following formula (unit: mgKOH / g). Acid value (mgKOH / g) = (5.611 × a × F) / S
however,
S: Sample collection amount (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)
F: Titer of 0.1N alcoholic potassium hydroxide solution <Measurement method of hydroxyl value>
The hydroxyl value represents the amount of hydroxyl group contained in 1 g of a hydroxyl group-containing resin as the amount of potassium hydroxide (mg) required to neutralize acetic acid bonded to the hydroxyl group when the hydroxyl group is acetylated. Is. The hydroxyl value was measured according to JIS K0070. In the present invention, when calculating the hydroxyl value, the acid value is taken into consideration as shown in the following formula.
<Measurement of hydroxyl value>
Precisely weigh about 1 g of the sample in an Erlenmeyer flask with a stopper, and add 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixture to dissolve the sample. Further, exactly 5 ml of an acetylating agent (a solution in which 25 g of acetic anhydride was dissolved in pyridine to make a volume of 100 ml) was added, and the mixture was stirred for about 1 hour. Phenolphthalein test solution is added to this as an indicator and lasts for 30 seconds. Then, titrate with 0.1N alcoholic potassium hydroxide solution until the solution turns pink.
The hydroxyl value was calculated by the following formula (unit: mgKOH / g).
Hydroxy group value (mgKOH / g) = [{(ba) × F × 28.05} / S] + D
however,
S: Sample collection amount (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)
b: Consumption (ml) of 0.1N alcoholic potassium hydroxide solution in the blank experiment
F: Titer of 0.1N alcoholic potassium hydroxide solution D: Acid value (mgKOH / g)
<Measurement method of glass transition temperature>
The binder resin from which the solvent was dried and removed was measured by using "DSC-1" manufactured by METTLER TOLEDO Co., Ltd. and raising the temperature from -80 to 150 ° C. at 2 ° C./min.

<Adjustment of binder resin>
The binder resin used in Examples and Comparative Examples was adjusted to a solution having a solid content of 20% using the solvent shown below. The composition ratio of the mixed solvent is described as a mass ratio.
-Solution of binder resin A-1-1: A solution of binder resin A-1 was diluted with toluene / methyl ethyl ketone / 2-propanol (1/1/1) to obtain a solution of binder resin A-1-1.
-Solution of binder resin A-2-1: Binder resin A-2 was diluted with toluene / 2-propanol (2/1) to obtain a solution of binder resin A-2-1.
-Solution of binder resin A-3-1: Binder resin A-3: Solution of binder resin A-3-1 obtained by diluting Byron 200 (made by Toyobo Co., Ltd., polyester resin) with toluene / methyl ethyl ketone (1/1). Got

<Conductive composition and conductive film>
(Example 1)
120 parts of A-1-1 solution (resin solid content 24 parts) as binder resin, 70 parts of B-1-1: scaly graphite CB-150 (manufactured by Nippon Graphite Co., Ltd.) as conductive carbon material, other than graphite B-2-1 as carbon material: 6 parts of furnace black # 3050 (manufactured by Mitsubishi Chemical), 204 parts of toluene / methyl ethyl ketone / 2-propanol (1/1/1 (mass ratio)) as solvent, in a mixer The mixture was added and mixed, and further placed in a sand mill for dispersion to obtain a conductive composition (1). Then, this conductive composition (1) was applied to a PET film having a thickness of 100 μm as a sheet-like substrate by using a doctor blade, and then heated and dried to adjust the thickness of the conductive film to 60 μm. .. The conductive carbon material contained in the conductive film is 76% by mass.
The obtained conductive film was evaluated by the following method. The evaluation results are shown in Table 1.

(Volume resistivity of conductive film)
The volume resistivity of the conductive film was determined by measuring (JIS-K7194) by the 4-terminal method using Loresta GP (manufactured by Mitsubishi Chemical Analytech Co., Ltd.). The evaluation results are shown in Table 1.
⊚: "Volume resistivity is less than 5 x 10 ^-3 Ω · cm (extremely good)"
◯: “Volume resistivity is 5 × 10 ^-3 Ω ・ cm or more and 1 × 10 ^-2 Ω ・ cm or less (good)”
○ △: “Volume resistivity is 1 × 10 ^-2 Ω ・ cm or more and 5 × 10 ^-2 Ω ・ cm or less (usable)”
Δ: “Volume resistivity is 5 × 10 ⁻² Ω · cm or more and 1 × 10 ^-1 Ω · cm or less (defective)”
×: “Volume resistivity is 1 × 10 ^-1 Ω · cm or more (extremely defective)”

(Adhesion of conductive film)
The conductive film produced above was cut into 6 grids in each of the vertical and horizontal directions at intervals of 2 mm from the surface of the conductive film to the depth reaching the substrate by using a knife. An adhesive tape was attached to this notch and immediately peeled off, and the degree of detachment of the conductive film was visually determined. The evaluation results are shown in Table 1, and the evaluation criteria are shown below.
○: "No peeling (level without practical problem)"
○ △: "Slight peeling (problem but usable level)"
Δ: "About half peeling"
×: "Peeling in most parts"

<Evaluation of coatability>
The conductive composition was evaluated by the coatability evaluation shown below. The conductive film was visually observed, and uneven coating (unevenness: evaluated by the shade of the coated surface) and pinholes (evaluated by the presence or absence of defects to which the conductive film was not applied) were judged according to the following criteria. The evaluation results are shown in Table 1.
(village)
◯: The shade of the conductive film is not confirmed (good).
Δ: There are 1 to 3 shades of the conductive film, but it is an extremely minute region (no problem in practical use).
X: The light film has four or more shades of light film, or the length of the light and shade stripes is 5 mm or more, and one or more (defective).
(Pinhole)
◯: No pinhole is confirmed (good).
Δ: There are 1 to 3 pinholes, but they are extremely small (no problem in practical use).
X: Four or more pinholes are confirmed, or one or more pinholes with a diameter of 1 mm or more (extremely defective).

(Examples 2 to 40, Comparative Examples 1 to 12)
With the composition ratios shown in Table 1, conductive compositions (2) to (40) and (a) to (l) were obtained by the same method as for the conductive composition (1).
Since the type of binder resin in Examples 16 and 27 is different from that in Example 1, toluene / 2-propanol (2/1) was used as the diluting solvent for producing the conductive composition.
Since the type of binder resin in Examples 17 and 28 is different from that in Example 1, toluene / methyl ethyl ketone (1/1) was used as the diluting solvent for producing the conductive composition.

The materials used in the examples are shown below.
<Binder resin (A)>
-A-1: Polyurethane resin-A-2: Polyamide resin-A-3: Polyester resin Byron 200 (manufactured by Toyobo Co., Ltd.)
<Carbon material (B)>
<Graphite (B-1)>
B-1-1: Scale graphite CB-150 (manufactured by Nippon Graphite Co., Ltd.) Average particle size 40 μm (catalog)
B-1-2: Scale graphite CPB (manufactured by Nippon Graphite Co., Ltd.) Average particle size 20 μm (catalog)
B-1-3: Scale graphite FB-100 (manufactured by Nippon Graphite Co., Ltd.) Average particle size 80 μm (catalog)
B-1-4: Flaked graphite CMX (manufactured by Nippon Graphite Co., Ltd.) Average particle size 40 μm (catalog)
B-1-5: Spheroidal graphite CGB-50 (manufactured by Nippon Graphite Co., Ltd.) Average particle size 50 μm (catalog)
B-1-6: Expanded graphite LEP (manufactured by Nippon Graphite Co., Ltd.) Average particle size 100 μm (catalog)
B-1-7: Artificial graphite PAG-5 (manufactured by Nippon Graphite Co., Ltd.) Average particle size 50 μm (catalog)
<Carbon material other than graphite (B-2)>
・ B-2-1: Furness Black # 3050B (manufactured by Mitsubishi Chemical Corporation)
・ B-2-2: Denka Black HS-100 (manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ B-2-3: Ketjen Black EC-300J (manufactured by Lion Specialty Chemicals)
・ B-2-4: Carbon nanotube VGCF (manufactured by Showa Denko KK)
・ B-2-5: Ketjen Black EC-600JD (manufactured by Lion Specialty Chemicals)

As shown in Table 1, the conductive film of the present invention has improved adhesion and conductivity more than before, and has been able to achieve both. From Comparative Examples 1 and 2, it was confirmed that when the mixing amount of the binder resin was small, the conductivity was good, but the adhesion to the substrate was lowered. On the other hand, as compared with Comparative Examples 3 and 4, the adhesion of the conductive film is improved as the mixing amount of the binder resin is increased, but the amount of the binder resin interposed between the carbon materials is increased in proportion to the increase, so that the contact between the carbon materials is increased. It was confirmed that it inhibits and causes a decrease in conductivity.
However, even when the mixing amount of the binder resin is large, it is kept within a predetermined range as in Examples 6 and 7, and by appropriately mixing a carbon material other than graphite, the adhesiveness is maintained and high. It was found that conductivity can be exhibited. It is considered that this is because a carbon material other than graphite intervenes in an appropriate amount between the graphite particles to strengthen the graphite while maintaining the conductive network. Another possible reason is that a carbon material other than graphite, which has a large specific surface area, traps the excess binder resin present in the conductive film and prevents the conduction network from being hindered.
On the other hand, when Comparative Examples 6 and 8 and Examples 4 and 5 were compared, it was confirmed that the predetermined conductivity could not be exhibited even when the mixing amount of the carbon material other than graphite was too large. It is considered that this is due to the fact that the formation of the conductive network between the graphite particles by the carbon material other than graphite in an excessive amount is hindered, and the resistance increases due to the carbon material other than graphite occupying most of the conductive network.
Further, when Comparative Examples 5 and 7 and Examples 4 and 5 were compared, it was confirmed that even when the mixing amount of graphite was too large, the predetermined conductivity or adhesion could not be exhibited depending on the mixing ratio with the binder resin. .. The reason for this is considered as follows. It is considered that when the amount of the binder resin is large, the mixing amount of the carbon material other than graphite is small, so that the binder resin hinders the formation of the conductive network between the graphite particles and the conductivity reaches a plateau. On the other hand, when the amount of the binder resin is small, it is considered that the adhesion derived from the binder resin is not exhibited because graphite occupies most of the constituent elements of the conductive film.
As described above, in the conductive film composed of the binder resin and the carbon material, excellent conductivity among the carbon materials is obtained by selectively controlling the mixing ratio of the binder resin, graphite, and the carbon material other than graphite in the conductive film. It was found that it enables network formation and exhibits excellent conductivity and adhesion.

Claims (6)

A conductive composition containing a binder resin (A) and a carbon material (B).
The carbon material (B) contains graphite (B-1) and a carbon material other than graphite (B-2).
The mass ratio of the solid content of the binder resin (A) to the carbon material (B) is 15:85 to 35:65.
The content of graphite (B-1) is 75.0 to 99.0% by mass in 100% by mass of the carbon material (B), and the graphite (B-1) contains flaky graphite.
A conductive composition, wherein the binder resin (A) contains polyurethane or polyamide . The conductive composition according to claim 1, wherein the content of graphite (B-1) is 80.0 to 99.0% by mass in 100% by mass of the carbon material (B). The conductive composition according to claim 1 or 2, wherein the content of graphite (B-1) is 90.0 to 97.5% by mass in 100% by mass of the carbon material (B). The conductive composition according to any one of claims 1 to 3, wherein the mass ratio of the solid content of the binder resin (A) to the carbon material (B) is 20:80 to 30:70. thing. The conductive composition according to any one of claims 1 to 4 , wherein the carbon material (B-2) other than graphite contains carbon black. A conductive film obtained by using the conductive composition according to any one of claims 1 to 5 .