JPS61195174A - Conductive coating - Google Patents

Abstract

PURPOSE:To provide the titled coating of high water and chemical resistance and good adherability, for application on paper, plastic film, etc., comprising conductive particulate matter and an aqueous vinyl copolymer containing specified proportion of specific sulfonic acid group-contg. monomer unit and polyvalent unsaturated monomer unit. CONSTITUTION:The objective coating comprising (A) an aqueous vinyl copoly mer prepared by copolymerization of monomer mixture containing (i) 0.5-30wt% of an alpha,beta-ethylenic unsaturated carboxylic acid (salt) and/or at least one sort of sulfonic acid group-contg. monomers of formula I, II, and III [R1 is H, Li, Na, K, or NH4; R2 is (CH2)n, (CH2)n-N(CH3)2-(CH2)m (m and n are each 1-8); R3 is H or CH3] and (ii) 0.5-20wt% of a polyvalent unsaturat ed monomer and (B) conductive particulate matter and further, if needed, (C) a polyvalent epoxy compound.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a conductive coating made of a vinyl aqueous polymer containing a conductive material, and is applicable to ordinary paper, plastic films, fibers, etc. The present invention relates to a suitable coating material capable of imparting electrical conductivity.

[Conventional technology]

2. Description of the Related Art Conductive plastics and conductive films that impart conductivity to non-conductive materials such as plastics have been known.

These can be obtained by melt-molding conductive additives, mainly conductive pigments and resins, together with plastic pellets to make conductive plastic moldings, or by melt-extruding and then stretching to make conductive films. However, these molded conductive plastics or films have poor moldability because they contain pigments, resins, auxiliary agents, etc., or the strength of the plastic itself is deteriorated due to the addition of a large amount of conductive agent. Weakness is a problem.

Furthermore, as an improved product, a film has been proposed in which an underbinder is applied to a plastic film and then conductivity is imparted by metal vapor deposition, but this film has not been put to practical use because the vapor-deposited surface tends to peel off.

There are also molded products and films that are primed and then laminated with a conductive film, but the conductive film itself is made by laminating or gluing the above-mentioned extruded stretched film. Therefore, the above-mentioned drawbacks cannot be sufficiently corrected.

On the other hand, there are also coating-type antistatic agents that are made by adding antistatic substances to synthetic resin emulsions, but in this case, the emulsifier used in the emulsion polymerization process during emulsion production makes the film waterproof during coating. In particular, these are lacquer-type products that use organic solvents, and are characterized by cumbersome processes such as salting out, water washing, and organic abrasion dissolution to remove emulsifiers. Therefore, there are problems with handling risks and air pollution during manufacturing, as well as problems with the working environment during application.

[Problem that the invention seeks to solve]

Conventional molded-in conductive plastics and conductive films have a problem in that imparting conductivity changes the inherent properties of the material, such as strength and formability, and it is difficult to laminate conductive films. In addition to the fact that the film itself is a built-in type, there are still problems with the adhesion of the laminate.

On the other hand, coating-type conductive materials such as synthetic resin emulsions are thought to be useful in solving the above-mentioned problems, but they have problems such as complicated processes and work environments. Therefore, in order to solve this problem, a coating type conductive material made of an aqueous solution type polymer may be considered, but such conductive materials are easily affected by moisture, which causes changes in electrical properties. Due to this risk, such water-based conductive materials are not currently in practical use.

Generally, lacquer type products using organic solvents are used, but with films, the surface may dissolve, the size and thickness etc. may change, high temperature drying is difficult, and there are dangers in handling during manufacturing. There are also problems with air pollution and the working environment during application.

[Means for solving problems]

The present invention is a conductive coating that solves the above-mentioned problems, and includes α,β-ethylenically unsaturated carboxylic acid or a salt thereof, and/or a sulfone represented by the following general formulas (1) to (3). 0.5 to 30% by weight of one or more acid group-containing monomers and 0.5 to 2% of polyunsaturated monomers
Consisting of a mixture of a vinyl-based aqueous copolymer (A) obtained by copolymerizing a monomer mixture in which 0% by weight is a part of the monomer constituents, and a conductive fine powder substance (B). A specific invention is a conductive coating material characterized by the above characteristics.

[General formula (1)] ■ CHg -CC-OR1-5O3R1 [General formula (2)] CHz = CCNHRz SO: +L [General formula (3
)] CHz -C-CO-Rx-5OsR+CHz
CORt-S(hR+ However, R3 is HI Lll Na, K, NHa, 6 is (CHri-, or (CHg)--N(CHs)z-(CHt)-(m-1
-B, n-1-8) R1 represents Hl or a C13 group.

The copolymer (A) used in the present invention contains an α,β-ethylenically unsaturated carboxylic acid or a salt thereof or/and a sulfonic acid group of the above general formula as a part of its monomer constituents. The monomer content is 0.5 to 30%, preferably 0.5% to 30%.
and 0.5 to 20%, preferably 0.5 to 15% of the polyunsaturated monomer, with the remainder being composed of other vinyl monomers copolymerizable with this. It is something to do.

Examples of the α,β-ethylenically unsaturated carboxylic acid or its salt include acrylic acid and methacrylic acid.

Itaconic acid, crotonic acid, maleic acid, cinnamic acid.

Fumaric acid, glutaconic acid, sorbic acid, etc. or their potassium, sodium, ammonium, etc. salts can be mentioned, and examples of the sulfonic acid group-containing monomer include (2-
Sodium salts, potassium salts, dipotassium salts, and N-(3-sulfopropyl, -N-acrylamidopropyl-N,N-dimethylammonium betaine, N-(3-sulfopropyl)-N-methacrylamidopropyl-N,N-dimethylammonium betaine, and other unsaturated monomers containing sulfonic acid groups. I can do it.

On the other hand, examples of polyunsaturated monomers include polyvalent unsaturated monomers such as ethylene glycol dimethacrylate 1,3-butylene glycol diacrylate, neopentyl glycol dimethacrylate polyethylene glycol diacrylate, trimethylolpropane trimethacrylate, and trimethylolethane triacrylate. esters of acrylic acid or polymethacrylic acid, halogenated polyacrylates such as dibrome neopentyl glycol dimethacrylate;
Or butadines such as halogenated polyvalent methacrylate, 1°4-butadiene, and isoprene.

Polyvalent allyl compounds such as N,N-methylenebisacrylamide, glyoxal tetraallyl ether, allyl sugar, furthermore, diallyl cyanurate, triallyl cyanurate, di(2-methylallyl) cyanurate,
Tri(2-methylallyl)cyanurate, 1.3.
5-Triacryloylhexahydro-S-) liazine, 1,3.5-1-dimethacryloylhexahydro-3-) liazine, 1,3-diacryloyl-3-) riazine, 1,3-dimethacryloyl-3 Examples include polyunsaturated cyclic nitrogen-containing compounds such as triazines such as -triazine and di- or tri-modified products of melamine.

Other vinyl monomers copolymerizable with these constituting the remainder include hydrophobic monomers capable of undergoing normal radical polymerization reactions, such as acrylic acid.

or methyl, ethyl, propyl methacrylate.

Butyl, isobutyl, 2-ethylhexyl, lauryl,
Esters such as cyclohexyl and hydroxyalkyl,
and acrylonitrile, methacrylonitrile, styrene, N-methylolacrylamide, and the like.

Each of the monomers having the above structure is polymerized to form a copolymer (A), and this can be carried out, for example, by the following method.

That is, from 0.5 to 0.5 to 0.5 to
A vinyl monomer mixture consisting of 30% polyunsaturated monomer, 0.5 to 20% polyunsaturated monomer, and the remainder other copolymerizable monomers is subjected to general radical monopolymerization in an organic solvent. It is obtained by polymerizing with an initiator, removing the organic solvent from the resulting polymer-containing liquid, and adding water and a basic substance to form an aqueous polymer.

In addition, a vinyl monomer mixture that does not contain α,β-ethylenically unsaturated carboxylic acids, their salts, sulfonic acid group-containing monomers, etc. is polymerized in an organic solvent, and all vinyl monomers are added to the resulting polymer. After graft polymerization of 0.5 to 30% of the α,β-ethylenically unsaturated carboxylic acid or its salt or/and sulfonic acid group-containing monomer based on the polymer using an organic peroxide catalyst. It can also be obtained by removing the organic solvent therein and adding water and a basic substance to form an aqueous polymer.

Furthermore, when obtaining a copolymer by polymerizing without using an emulsifier, the following method may be used.

That is, as a first step, a vinyl monomer mixture containing an α,β-ethylenically unsaturated carboxylic acid or a salt thereof and/or a sulfonic acid group-containing monomer is polymerized in an organic solvent to obtain a polymer. The containing liquid is made into an aqueous polymer by removing the organic solvent therein and adding water and a basic substance, and in a second step, a vinyl monomer is converted into an aqueous polymer using the aqueous polymer obtained in the first step as a core. It can be obtained by polymerizing the compound by radical polymerization reaction.

In this case, the constituent components of the monomer in this invention are α constituting the core aqueous polymer obtained in the first step.
, β-ethylenically unsaturated carboxylic acid and its salt, and/or the total amount of vinyl monomers other than the sulfonic acid group-containing monomer and the vinyl monomer used in the second step, α , β-ethylenically unsaturated carboxylic acid or its salt,
It is used as a vinyl monomer constituting the remainder of the sulfonic acid group-containing monomer.

In this way, if the amount of α,β-ethylenically unsaturated carboxylic acid or its salt or/and sulfonic acid group-containing monomer is less than 0.5% as a proportion of the total monomers, the obtained The stability and water solubility of the water dispersion of the polymer itself, as well as the dispersibility of pigments, are impaired, and if the content exceeds 30%, the water resistance of the film as a conductive coating material reaches its peak. This would defeat the purpose of the invention.

Further, the polyunsaturated monomer is used in a proportion of 0.5 to 20%, preferably 0.5 to 15%, based on the total amount of monomers, and if this is less than 0.5%. If it exceeds 20%, other monomer constituents such as α, β-ethylenically unsaturated carboxylic acid, its salt, sulfonic acid group-containing monomer, etc., and the remainder cannot be exhibited. In relation to the blending ratio with other constituent vinyl monomers, crosslinking properties appear strongly, causing gelation, etc., inhibiting the dispersibility of the conductive fine powder material (B), and reducing the conductive coating material. Manufacturing becomes difficult.

The conductive coating material of the present invention is a mixture of the copolymer (A) obtained as described above and a conductive fine powder substance (B). carbon, conductive metals (e.g. gold).

silver, copper, aluminum, nickel, tin, lead, titanium, etc. and their alloys), conductive metal oxides (e.g. nickel, aluminum, copper, titanium).

oxides such as tin) are preferably used.

There is no particular restriction on the particle size of such a conductive fine powder substance, but it is preferable to have a small particle size, preferably in the range of 10 μm or less.

The blending ratio of the conductive fine powder substance (B) to the copolymer (A) varies depending on the purpose of imparting conductivity as a coating material, but preferably (A) / (B) (solid content weight ratio) is 9773. ~20/80 = 32.3 ~ 0.25, and when (A) / (B) exceeds 32.3, the conductivity tends to decrease due to the excess amount of resin, and conversely, 0
．． When it is less than 25, although the conductivity is good, the resulting coating becomes brittle and cannot withstand long-term use.

Next, as a dependent invention to the specific invention of this invention, a mixture of the copolymer (A), a conductive fine powder (B), and a polyvalent epoxy compound (C) is also useful as a conductive coating material. It is.

Such polyvalent epoxy compounds contain two or more epoxy groups in one molecule and preferably have a molecular weight of 10,
Examples include bisphenol A diglycidyl ether, bisphenol A diβ-methylglycidyl ether, bisphenol F diglycidyl ether, tetrahydroxylphenylmethane tetraglycidyl ether, resorcinol diglycidyl ether, and pro-modified bisphenol A diglycidyl ether. Ether, diglycidyl ethers such as novolac diglycidyl ether, polyalkylene glycol diglycidyl ether, glycerin triglycidyl ether, phthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, trimethylpropane triglycidyl ester, dimer acid diglycidyl ester etc., polyvalent glycidyl amines such as tetraglycidyldiaminodiphenylmethane and triglycidyl isocyanurate, and linear aliphatic epoxy resins such as epoxidized polybutadiene and epoxidized soybean oil.

Such a polyvalent epoxy compound is effective in imparting crosslinking properties to the copolymer (A) and improving the water resistance and chemical resistance of the obtained conductive coating material. (A)/(C) -98/2 to 7 as the weight ratio of the polyepoxy compound (C) to the aqueous copolymer (A)
0/30 = 49 to 2.33.

If the polyvalent epoxy compound (C) is too small relative to the copolymer (A), the effect of imparting crosslinking properties will be poor, and the obtained conductive coating will not have better water resistance and chemical resistance. It is difficult to expect any effect, and if the amount is too large, the crosslinking reaction will be too strong, resulting in gelation, and the copolymer (A) will lack chemical stability over time.

On the other hand, for the conductive fine powder substance (B), (^) + (C
)/(B) as a weight ratio of 9773 to 20/80-3
The range of 2.3 to 0.25 is preferable, and (^) +
If (C)/(B) exceeds 32.3, the electrical conductivity will be poor due to the excess amount of resin, while if it is less than 0.25, the electrical conductivity of the film will be good but it will be difficult to obtain a good electrical conductivity. The resulting coating becomes brittle and difficult to use over a long period of time.

[For production]

The copolymer (A) in this invention is an aqueous copolymer that is highly water-dispersible and water-soluble, and as described above, this copolymer is composed of α,β-ethylenic copolymers that constitute one component of the monomer. It is obtained in the form of a hydrophilic carboxyl group or sulfonic acid group bonded around a lipophilic polymer using an unsaturated carboxylic acid or a salt thereof, a sulfonic acid group-containing monomer, or the like.

This copolymer (A) is prepared by combining it with a conductive fine powder substance (B).
) and apply it to the object to be coated, it is possible to form a film with excellent conductivity and high water and chemical resistance.
In particular, it can impart excellent electrical conductivity to plastics that have a high degree of triboelectrification.

In addition, as monomer constituents in the copolymer (A),
Copolymer (A) by using a polyunsaturated monomer
It is possible to make the film appropriately conductive, thereby improving the conductive performance of the film.

Regarding the dependent invention of this invention, a polyvalent epoxy compound is further added as a component (C) to both components (A) and (B) to cause a crosslinking reaction in the copolymer (A), and the copolymer (A) is utilized. promotes water evaporation from the paint film during
It is possible to form a strong conductive film with excellent water and chemical resistance and good adhesion.

〔Example〕

Examples and comparative examples will be described below.

A monomer mixture having a monomer composition as shown in Table 1 below was mixed with a solvent (methyl ethyl ketone), and azobisisobutyronitrile was added as a polymerization initiator.
The resulting copolymer was neutralized with methylamine, and the solvent was removed to obtain an aqueous copolymer solution with a concentration of 40%.

Next, furnace black (average particle size 5μ, specific resistance 10-IΩc) was added to this copolymer solution as conductive carbon.
ll) was added and kneaded using a three-roll dispersion roll to obtain a conductive coating.

The amounts of the copolymer solution and conductive carbon were varied, and these were applied to the surface of the paper base material at 20 μ/Dry (1
20° C.), and a surface resistance value measurement, a hand kneading test, and a sellotape peeling test were performed.

The results are shown in Table 1.

In addition, each test was conducted according to the following test method.

Surface resistance value: Measured with an electrical conductivity meter (manufactured by Tsukiyama Kagaku Kikai Seisakusho).

Hand kneading test; For a 13alX 20cm sample,
Determine whether or not it has fallen off due to hand kneading.

Sellotape@Release test H1cmXlco+ cross-cut test (determined by IN-eye matrix test) ×---All IAM Δ--60 or more peeled off.

○・－・Unable to get more than 40 pieces ◎・−・I could not remove it at all.

[Margin below]

Table 1 Table 5 and 1 to 3 A monomer mixture whose monomer composition is as shown in Table 2 below was mixed in a solvent (ethyl alcohol), and diazoaminobenzene was added as a polymerization initiator to form 78 to 3 monomers. 80℃
After reacting for 5 hours, the obtained copolymer was neutralized with aqueous ammonia, and the solvent was removed to obtain an aqueous solution of the copolymer of Example 5 and Comparative Examples 1 to 3 having a concentration of 50%.

Next, conductive silver powder (average particle size 1 μm, specific resistance 10 −4 Ωcm) was added to the copolymer aqueous solutions of Example 5 and Comparative Examples 1 to 3 as a conductive fine powder substance in the copolymer/silver powder ratio.
They were added at a ratio of 80/20 (weight ratio) and dispersed and mixed using a colloidal mill to obtain a coating material.

These coating agents are applied to the surface of the vinyl chloride film at a rate of lOμ/
The coating was applied in a dry manner (60°C).

These were subjected to the same tests as in Example 1, and the results are shown in Table 2 together with the composition of each monomer constituting the copolymer.

[Margin below]

The monomer compositions of Table 2 6.7 and 4-7 are shown in Table 3 below (1) to (I[[
) was mixed with a solvent (butyl alcohol), reacted for 4 hours at a temperature of 90 to 95°C using benzoyl peroxide as a polymerization initiator, and neutralized with ammonia water to form a copolymer. I got it.

Table 3 Using the copolymers obtained with the compositions shown in Table 3 (1) to (III) above and using or not using conductive furnace black as the conductive fine powder material, Examples 6.7 and Conductive coatings of Comparative Examples 4 to 7 were obtained.

These coating materials were applied to the surface of a corona-treated polypropylene film at a rate of 15 μ/Dry (80° C.).

The test results and other results for these are shown in Table 4.

[Margin below]

8 and 8.9 20% of the copolymer obtained in Example 5 was used and this was converted into a core (
Precursor) and the monomers shown in Table 5 were added thereto to obtain copolymer emulsions of Example 8 and Comparative Example 8 in which no emulsifier was used.

In addition, a copolymer emulsion of Comparative Example 9 was obtained without using the copolymer of Example 5, but using an emulsifier (sodium dobesylbenzenesulfonate) according to the monomer composition shown in Table 5. .

Conductive titanium oxide powder (average particle size 0.4μ, specific resistance 6) was added to these copolymer emulsions as a conductive fine powder substance.
Ωam) copolymerized emulsion/titanium oxide powder 60/
40 (weight ratio) and kneaded with a three-roll dispersion roll to obtain a coating material.

These coating agents were applied to the surface of a soft vinyl chloride film for 10 minutes.
Example 1
A similar test was conducted. The results are shown in Table 5 together with the monomer constituents.

[Margin below]

The numbers in parentheses in Table 5 Monomer composition indicate the composition corresponding to 20% copolymer.

9 and 10 By one-stage polymerization, polymers serving as the basis for Example 9 and Comparative Example 10, each having a different monomer composition, were obtained, and this was
Graft polymerization was carried out by step polymerization to obtain 30% copolymer aqueous solutions of Example 9 and Comparative Example 10, respectively.

In this case, n-propyl alcohol was used as the solvent in the one-stage polymerization, azobisisobutyronitrile was used as the polymerization initiator, and the reaction temperature was 98 to 100°C for 3 hours.

In the two-stage polymerization, the same n-propyl alcohol was used as a solvent, ketone peroxide was used as a graft initiator, and the reaction was carried out at 120° C. for 3 hours under pressure and sealing.

Next, conductive tin oxide powder (average particle size 5μ, specific resistance 1Ωm) was added to these copolymer aqueous solutions as a conductive fine powder substance.
) was added in a copolymer/tin oxide powder ratio of 85/15 (weight ratio) and kneaded using a three-roll dispersion roll to obtain a coating material.

These coating materials were applied to the surface of high-density polyethylene treated with corona discharge at a rate of 20 μ/Dry (90° C.). Then, the same tests as in Example 1 and a water resistance test were conducted on these. The results are shown in Table 6 together with the composition of the constituent components of the copolymer.

In the water resistance test, the sample was immersed in water at 25° C. for 1 hour, and the state of the film was observed.

[Margin below]

Table 6 This 3111M monomer composition is as shown below. Using a monomer mixture as a solvent, using isopropyl alcohol and a polymerization initiator, azobisisobutyronitrile, at a temperature of 80 to 85°C. When reacted for 5 hours, the copolymer gelled and neutralization was impossible.

[Monomer composition]

Methacrylic acid・・・−・−・・−・−・−・−・・−−
---------5% 1.3-butylene glycol diacrylate--25%
Isobutyl acrylate ---m-・--・40% methyl methacrylate・-----
-30% 1O111 and 12 In addition to the copolymer and conductive carbon (furnace black) obtained in Example 2, as a polyepoxy compound,
Bisphenol A diglycidyl ether was added to obtain a conductive coating (Example 10), and bisphenol A diglycidyl ether was added to the copolymer and conductive carbon (furnace black) obtained in Example 3 in the same manner. In addition, a conductive coating was obtained (Example 11).

These were applied to the surface of a corona-treated medium-density polyethylene film at a rate of 20 μ/Dry (80° C.) and tested for surface resistance, water resistance, chemical resistance, boiling water resistance, etc.

The results were compared to the conductive coating material of Example 2 (Comparative Example 12) in which the bisphenol A diglycidyl ether was not added.
A comparison is shown in Table 7.

In addition, each test method was implemented as follows.

(1) Water resistance test - Observe the surface condition after being immersed in -25℃ water for 1 day and night (2) Hexane resistance test - Observe the surface condition after being immersed in hexane for 1 day and night (3) Hydrochloric acid resistance test・------------1%
Observe the surface condition after being immersed in hydrochloric acid for a day and night (4) Boiling water resistance test---1---1 in boiling water
Observe the surface condition after boiling for a period of time (5) Moisture resistance test - - - - - - Surface when the sample is placed in an environment of constant temperature (30°C) and constant relative humidity Resistance value (Ω/, ff1) Table 7 To the copolymer obtained in Example 5 and conductive carbon (furnace black), triglycidyl isocyanurate was added as a polyvalent epoxy compound. A conductive coating material was obtained (Example 12), and triglycidyl isocyanurate was further added as a polyvalent epoxy compound to the copolymer obtained in Example 9 and conductive tin oxide. A conductive coating was obtained (Example 13).

Using these, apply 20 μm on the surface of the polyester film.
/Dry (150°C) and tested in the same manner as in Example 8.

The results are shown in Table 8.

[Margin below]

8 Tables 14.15 and 13 Using the copolymers obtained in monomer compositions CI) and (II) in Table 3, conductive furnace black was used as the conductive fine powder material, and polyvalent epoxy was added to this. Conductive coating materials of Examples 14 and 15 and Comparative Example 13 were obtained with or without addition of trimethylpropane triglycidyl ester as a compound.

These coating materials were applied to the surface of a corona-treated polypropylene film at a rate of 15 μ/Dry (80° C.).

The test results and other results for these are shown in Table 9.

[Margin below]

Table 9 [Effects of the Invention] According to the specific invention of the present invention, the copolymer (A) is a water-based copolymer different from conventional emulsion polymers, and this is mixed with a conductive fine powder substance (B). ), it was possible to obtain a new aqueous solution type or paste type conductive coating material.

In general, aqueous solution-type conductive coatings are easily affected by humidity (moisture), which is thought to cause changes in electrical properties, but according to the conductive coating of the present invention, the above embodiments However, as is clear, it not only has excellent conductive performance, but also has particularly excellent water resistance and chemical resistance, and also has good adhesion to the coated object, making it ideal for use as a conductive coating. It is something.

Furthermore, according to the dependent invention of this invention, the above (A) and (B)
By blending a predetermined amount of a polyvalent epoxy compound as component (C) with both components, a conductive coating containing a crosslinked aqueous copolymer can be obtained, and the water resistance of the coating can be improved.
Chemical resistance can be further improved.

Claims (1)

[Scope of Claims] 1) α,β-ethylenically unsaturated carboxylic acid or a salt thereof, and/or one of the sulfonic acid group-containing monomers represented by the following general formulas (1) to (3) or 0 for 2 or more types
．． 5-30% by weight and 0.5-20% of polyunsaturated monomer
% by weight and a mixture of a vinyl-based aqueous copolymer (A) obtained by copolymerizing a monomer mixture as a part of the monomer constituents and a conductive fine powder substance (B). A conductive coating material characterized by: [General formula (1)] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [General formula (2)] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [General formula (3)] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ However, R_1 is H, Li, Na, K, or NH_4, and R_2 is (CH_2)_n or (CH_2)_n-N(CH_3)_2-(CH_2)
_m (m=1-8, n=1-8) R_3 represents H or CH_3 group. (2) α,β-ethylenically unsaturated carboxylic acid or its salt, and/or one or more sulfonic acid group-containing monomers represented by the general formulas (1) to (3) below. .5-30% by weight and 0.5-2% of polyunsaturated monomer
A vinyl aqueous copolymer (A) obtained by copolymerizing a monomer mixture in which 0% by weight is a part of the monomer constituents, a conductive fine powder substance (B), and a polyvalent epoxy An electrically conductive coating comprising a mixture with compound (C). [General formula (1)] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [General formula (2)] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [General formula (3)] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ However, R_1 is H, Li, Na, K, or NH_4, and R_2 is (CH_2)_n or (CH_2)_n-N(CH_3)z-(CH_2)_
m (m=1-8, n=1-8) R_3 represents H or CH_3 group.