JPH11140345A - Conductive coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a conductive coating composition having excellent adhesion to a polyolefin plastic substrate, solvent resistance, film hardness and storage stability and low surface resistivity by mixing a resin composition obtained by radical-polymerizing a chlorinated polyolefin resin having a specified or lower chlorine content with a radical-polymerizable monomer in a specified ratio with a metallic powder. SOLUTION: There is used a resin composition obtained by radical- polymerizing 2-60 pts.wt. chlorinated polyolefin resin having a chlorine content of 50 wt.% with 98-40 pts.wt. radically polymerizable monomer together with, optionally, an organic solvent. It is desirable that the radically polymerizable monomer comprises 0.05-10.0 wt.%, based thereon, polyfunctional radically polymerizable monomer. The radically polymerizable monomer is desirably one which can give a radical polymer having a glass transition temperature of 50 deg.C or above. The resin composition is desirably one having a weight- average molecular weight of 50,000-1,000,000 in terms of the polystyrene.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention provides a conductive coating composition, particularly a conductive base material such as polyolefin, which is excellent in performance such as adhesion and solvent resistance and is excellent in conductivity even without being subjected to a primer treatment. The present invention relates to a coating composition.

2. Description of the Related Art

[0002] Conventional technologies include, for example, electric appliances,
In OA equipment, mobile communication devices, battery-powered vehicles, lamps, etc., the influence on the external environment due to unnecessary radiation electromagnetic waves generated during the operation of these devices, malfunction of peripheral devices, or the influence of unnecessary radiation electromagnetic waves from outside. Since malfunctions of these devices often cause problems, reduction of unnecessary radiation electromagnetic waves is an important issue.

[0003] Unnecessary radiation electromagnetic waves can be reduced by electromagnetically shielding the inside of a product, which is a source of unnecessary radiation electromagnetic waves, by using a conductive material such as a metal plate, or by plating the inner surface of a cabinet of a device to prevent the radiation. Electromagnetic shielding by imparting properties, and electromagnetic shielding by applying a conductive paint, etc. have been adopted.

[0004] Among these electromagnetic shielding methods, the method of applying a conductive paint is particularly advantageous in terms of easiness of operation, compatibility with a cabinet having a complicated shape, cost, and the like.

On the other hand, looking at the materials constituting the products, polyolefin-based substrates are often used as materials used for cabinets of the electric appliances and the like because of their excellent cost and recyclability. It is becoming.

In the conventional case, a conductive paint which has been conventionally used for an ABS resin material or the like is often applied to a polyolefin material. In this case, a polyolefin resin generally has high crystallinity and a small polarity, and thus, It has the drawback that paints are difficult to adhere, so it is necessary to perform pretreatment such as physical treatment such as polishing, chemical treatment with chromic acid mixed solution, solvent, etc., and other treatments such as plasma or corona discharge at the time of painting. is there. These pretreatment steps have problems such as the necessity of equipment, the inability to treat uniformly depending on the shape of the object to be coated, and the increase in cost.

[0007] Further, various primers having good adhesion to the polyolefin-based substrate have been proposed, but when such a primer is used, there is still a problem that the cost is increased.

[0008] adhesion to polyolefin materials,
As a coating resin composition having improved coating properties such as solvent resistance and hardness, a resin composition comprising a chlorinated polyolefin and an acrylic polymer is known. In the case where the conductive paint composition is formed, in addition to the separation of the resin component during the storage of the paint caused by poor compatibility of the resin, when the conductive paint is formed by mixing metal powder and the like, Since there is a problem such as an increase in the electric resistance value of the coating film surface, a conductive paint satisfying both the adhesion to a polyolefin material and a low surface resistance value has not yet been proposed.

The present invention has been made in view of such a conventional problem, and has a property of adhering to a polyolefin-based plastic base material that has not been subjected to a physical and chemical pretreatment step, and has a solvent resistance. An object of the present invention is to provide a conductive coating composition which is excellent in properties, coating film hardness, storage stability and has a low surface electric resistance value.

[Means for Solving the Problems]

[0010] In order to solve the above-mentioned problems, the invention according to claim 1 is to provide 2 to 60 parts by weight of a chlorinated polyolefin resin having a chlorine content of 50% by weight or less and at least 1 part by weight.
Provide a conductive coating composition obtained by mixing a resin composition obtained by radical polymerization of 98 to 40 parts by weight of at least 98 kinds of radically polymerizable monomers together with an organic solvent, if necessary, and metal powder. Things.

[0011] In order to solve the above-mentioned problems, the invention according to claim 2 is characterized in that the radical polymerizable monomer according to claim 1 has a content of 0.05% by weight to 10.0% by weight. An object of the present invention is to provide a conductive coating composition characterized by being a polyfunctional radical polymerizable monomer.

[0012] In order to solve the above-mentioned problems, the invention according to claim 3 is directed to a method in which the radical polymerizable monomer according to any one of claims 1 and 2 has a glass transition at the time of radical polymerization. It is intended to provide a conductive coating composition having a temperature of 50 ° C. or higher.

[0013] In order to solve the above-mentioned problems, the invention according to claim 4 provides a resin composition used for the conductive coating composition according to any one of claims 1 to 3;
It is intended to provide a conductive coating composition having a weight average molecular weight of 50,000 to 1,000,000 in terms of polystyrene.

[Embodiment of the present invention]

[0014] The resin composition used for the conductive coating composition of the present invention contains a chlorinated polyolefin resin. The chlorinated polyolefin resin is a polyethylene resin having a chlorine content of 50% by weight or less, a polypropylene resin, an ethylene-propylene copolymer, an ethylene-vinyl acetate copolymer, and a carboxylic acid or an acid anhydride-modified polymer thereof. And so on.

The unsaturated carboxylic acid or anhydride thereof for the polymer modification treatment includes crotonic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid and the like.

The chlorine content of the chlorinated polyolefin resin used in the resin composition of the present invention is preferably 50% by weight or less. If the chlorine content is 50% by weight or more, the adhesion to the polyolefin resin base material to be coated decreases, which is not preferable.

Various chlorinated polyolefin resins are commercially available, such as Supercron 773H (a chlorinated polyolefin manufactured by Nippon Paper Co., Ltd., a 45% toluene solution), Supercron 822 (a chlorinated polyolefin manufactured by Nippon Paper Co., Ltd.) Supercron 892L (Nippon Paper Industries chlorinated polyolefin, toluene 20% solution), Supercron 832L (Nippon Paper Industries chlorinated polyolefin, toluene 30% solution), Supercron E (Japan) Chlorinated polyolefin manufactured by Paper Manufacturing Co., Ltd., 20% toluene solution), Hard Len 14L
LB (30% solution of chlorinated polyolefin, toluene manufactured by Toyo Kasei Kogyo Co., Ltd.), 14 ML (30% solution of chlorinated polyolefin, toluene manufactured by Toyo Kasei Kogyo Co., Ltd.), Hardlen BS-40 (Toyo Kasei Kogyo Co., Ltd.) Chlorinated polyolefin, toluene 50% solution), Hardlen B-13 (Toyo Kasei Kogyo Co., Ltd. chlorinated polyolefin, toluene 30% solution), Hardlen B-4000
Various chlorinated polyolefin resins such as (chlorinated polyolefin manufactured by Toyo Kasei Kogyo Co., Ltd., toluene 30% solution) can be used.

The content of the chlorinated polyolefin resin in the solid of the resin composition used in the conductive coating composition of the present invention is preferably 2% by weight to 60% by weight. More preferably, it is 3% by weight to 20% by weight, and still more preferably 3% by weight.
% By weight.

For this reason, if the content of the chlorinated polyolefin resin is 2% by weight or less, the adhesion to the polyolefin-based material becomes insufficient, which is not preferable. Also,
When the content of the chlorinated polyolefin resin is 60% by weight or more, the specific electric resistance value of the coating film surface when the conductive coating material is formed is not preferable. Since the specific electrical resistance value of the coating film surface increases as the content of the chlorinated polyolefin resin in the resin composition increases, it should be set to the minimum content within a range that satisfies the adhesion to the coating material. Is preferred.

[0020] The resin composition used in the conductive coating composition of the present invention includes the chlorinated polyolefin resin 2 to 60.
Parts by weight, and a resin composition obtained by radically polymerizing 98 to 40 parts by weight of at least one or more radical polymerizable monomers together with an organic solvent as necessary. Esters of acrylic acid or methacrylic acid, such as methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate,
Acrylics such as butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate Acid or methacrylic acid having 1 to 18 carbon atoms
Alkyl esters, methoxybutyl acrylate, methoxybutyl methacrylate, methoxyethyl acrylate,
Acrylic acid such as methoxyethyl methacrylate, ethoxybutyl acrylate, ethoxybutyl methacrylate, or alkoxyalkyl ester having 2 to 18 carbon atoms of methacrylic acid, acrylic acid such as allyl acrylate, allyl methacrylate, or 2 carbon atoms of methacrylic acid -8 alkenyl esters, hydroxyethyl acrylate,
Acrylic acid such as hydroxyethyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, or acrylic such as hydroxyalkyl ester of methacrylic acid having 2 to 8 carbon atoms, allyloxyethyl acrylate, allyloxyethyl methacrylate Acid or methacrylic acid having 3 to 18 carbon atoms
Alkenyloxyalkyl esters.

As the vinyl aromatic compound, for example,
Styrene, α-methylstyrene, vinyltoluene, p-
There is chlorostyrene.

Examples of the polyolefin compound include butadiene, isoprene and chloroprene. Others
Caprolactone-modified acrylate compound, caprolactone-modified methacrylate, acrylonitrile, methacrylonitrile, methyl isopropenyl ketone, vinyl acetate, vinyl propionate, vinyl pivalate, acrylamide, N-methylol acrylamide, N-methylol methacrylamide, N-methylol Examples thereof include acrylamidobutyl ether, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, allyl alcohol, and maleic acid.

There is a correlation between the molecular weight of the resin composition used in the conductive coating composition of the present invention and the surface resistivity of the conductive coating film, and the electrical resistance decreases as the molecular weight increases. For this reason, the molecular weight is preferably large,
In consideration of coating workability at the time of coating, the weight average molecular weight in terms of polystyrene is preferably 50,000 to 1,000,000. More preferably, it is 100,000 to 500,000.

The resin composition used in the conductive coating composition of the present invention is preferably a method using a polyfunctional radical polymerizable monomer as a method for obtaining a resin having a large weight average molecular weight in terms of polystyrene.

The reason for this is that the resin composition is preferably subjected to a reaction at a relatively high temperature in order to efficiently graft polymerize a chlorinated polyolefin resin with a radical polymerizable monomer. When only the conductive monomer is used, it is difficult to obtain a resin having a large molecular weight, and thus it is difficult to obtain a conductive paint having a low electric resistance value. Therefore, if a polyfunctional radical polymerizable monomer is used in combination, a high-molecular weight resin composition having a high grafting efficiency can be obtained. That is, a conductive paint having excellent storage stability and adhesion to a polyolefin-based material and having a low electric resistance value can be obtained.

Examples of the polyfunctional radical polymerizable monomer include ethylene glycol dimethacrylate, ethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, 1.3-butylene glycol dimethacrylate, 1.3-butylene glycol diacrylate, 1,6-dimethacrylate
Examples thereof include hexanediol, 1,6-hexanediol diacrylate, trimethylolpropane trimethacrylate, and trimethylolpropane triacrylate.

The amount of the polyfunctional radical polymerizable monomer used is preferably 0.05% by weight to 10.0% by weight of the radical polymerizable component. More preferably, it is 0.1% by weight to 5% by weight. The amount of the polyfunctional radical polymerizable monomer used is
When the content of the radical polymerizable component is 0.05% by weight or less, the effect of increasing the molecular weight of the resin composition is small, so that it is not preferable. In addition, the amount of the polyfunctional radical polymerizable monomer used,
If the content of the radical polymerizable component is 10.0% by weight or more, the molecular weight becomes too large, which may cause gelation or a problem that a large amount of radical polymerization initiator is required to avoid the gelation. Absent.

When the radically polymerizable monomer or two or more radically polymerizable monomers are used, the resin composition used in the conductive coating composition of the present invention is obtained by polymerizing only a mixture thereof. It is preferable to use a radically polymerizable monomer having a glass transition temperature of 50 ° C. or higher of the polymer.

The reason for this is that there is a correlation between the glass transition temperature of the radical polymerizable monomer used in the resin composition and the specific electrical resistance value of the coating film surface when a conductive paint is formed. It is not preferable to use a radical polymerizable monomer having a temperature of 50 ° C. or lower because the specific electric resistance of the surface of the coating film when a conductive coating material is formed does not decrease.

In this case, the glass transition temperature of the resin composition varies depending on the type, amount, and molecular weight of the chlorinated polyolefin resin to be used, and the measured value is generally difficult to describe clearly. The glass transition temperature described in the claims of the present invention is limited to the radical polymerizable monomer component. For example, in the case of a glass transition temperature Tg of a copolymer composed of two kinds of monomers, the glass transition temperature of both components is (Tg
1, Tg2) and weight fractions (W1, W2). Tg = W1 × Tg1 + W2 × Tg2

The resin composition used in the conductive coating composition of the present invention is a resin obtained by subjecting a radical polymerizable monomer component to radical polymerization by a solution polymerization method, such as a usual acrylic resin or vinyl resin. Can be obtained by the same method and conditions as in the radical polymerization reaction of As an example of such a synthesis reaction, each monomer component is dissolved in an organic solvent, and is dissolved in a nitrogen atmosphere in the presence of a radical polymerization initiator.
A method of heating with stirring at a temperature of about 0 ° C. can be shown. The reaction time may be generally about 1 to 10 hours.

As the organic solvent, ether solvents, ester solvents, hydrocarbon solvents, alcohol solvents and the like can be used.

As the radical polymerization initiator, those usually used can be used, and examples thereof include:
Examples thereof include peroxides such as benzoyl peroxide and t-butylperoxy-2-ethylhexanoate, and azo compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile.

The conductive coating composition of the present invention is obtained by dispersing a metal powder in the resin composition.
Examples of the metal powder include powdered copper, nickel,
Silver, silver-plated copper and the like can be exemplified, and a conductivity imparting material used in a usual conductive paint composition can be used.

The conductive coating composition of the present invention can be mixed with, for example, a polyester resin, an alkyd resin, an epoxy resin, an acrylic resin, a urethane resin, a cellulose resin, an isocyanate resin, and the like, if necessary. Preferably, their amounts do not exceed 30% by weight in order to maintain the effect of the present invention.

Further, the resin composition for a conductive paint of the present invention may contain, if necessary, known coating surface adjusters, fluidity adjusters, ultraviolet absorbers, light stabilizers, curing catalysts, extenders, coloring. Pigments, metal pigments, mica powder pigments, dyes, organic solvents and the like can be added.

The conductive coating composition is usually made of an organic solvent, for example, a hydrocarbon solvent such as toluene and xylene, a ketone solvent such as methyl ethyl ketone and methyl isobutyl ketone, an ester solvent such as ethyl acetate and butyl acetate,
Dioxane, diluted with a single or mixed solvent such as ether solvents such as ethylene glycol diethyl ether,
The coating can be performed by a general coating method such as spray coating, roll coating, brush coating and the like.

【Example】

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.

Example 1 (Synthesis of resin composition used for conductive coating composition) A 1-liter round bottom four-necked flask equipped with a nitrogen inlet tube, a thermometer, a cooling tube, a dropping funnel, and a stirrer was prepared. Toluene 37
7.0 g, Hardlen B-4000 (chlorinated polyolefin resin, 30% toluene solution, manufactured by Toyo Kasei Co., Ltd.)
0.0 g, 206.4 g of methyl methacrylate, 90 g of tertiary butyl methacrylate, 3 g of methacrylic acid, and 0.6 g of ethylene glycol dimethacrylate were added, and the mixture was heated and stirred while blowing nitrogen gas. When the temperature in the flask reached 105 ° C., a mixed solution obtained by dissolving 0.9 g of Cadox B-75AW (benzoyl peroxide manufactured by Kayaku Akzo Co., Ltd., 75% water wet product) with 5 g of toluene was added.

The temperature in the flask was maintained at 105 ° C., and 45 minutes after the initial addition of Cadox B-75 AW, 9
After 0 minutes and 135 minutes, respectively, Cadox B-75AW
A mixed solution obtained by dissolving 0.9 g in 5 g of toluene was added, and the temperature in the flask was further maintained at 105 ° C. for 90 minutes. Thereafter, the reaction was terminated by cooling to room temperature, and 35 g of toluene was added. A resin composition used for a paint was obtained.

In this example, the heating residue of the coating resin composition was 40.0%, the composition contained 6.5% by weight of chlorinated polyolefin resin in solids, and the glass transition temperature of the acrylic component was 106%. ° C, 0.2 of radical polymerizable monomer
The weight% was a polyfunctional monomer, and the weight average molecular weight of the resin composition in terms of polystyrene was 170,000.

(Preparation of Conductive Coating Composition) 30 g of the resin composition of Example 1 and Carponyl 255 (INCO (
Example 1 was prepared by mixing 35 g of nickel powder (manufactured by Co., Ltd.), 20 g of toluene, and 15 g of xylene by dispersion.
Was obtained.

Example 2 (Synthesis of Resin Composition Used for Conductive Paint Composition) Under the same polymerization conditions as in Example 1, 362.0 g of toluene and Hardlen B-4000 (chlorinated polyolefin manufactured by Toyo Kasei Co., Ltd.) 130.0 g of resin, 30% solution of toluene), 206.4 g of methyl methacrylate, 90.0 g of tertiary butyl methacrylate, 3 g of methacrylic acid, and 0.6 g of ethylene glycol dimethacrylate were polymerized and polymerized. A resin composition used for a paint was obtained.

In this example, the heating residue of the coating resin composition was 40.0%, the composition contained 11.5% by weight of chlorinated polyolefin resin in solid content, and the glass transition temperature of the acrylic component was 106 ° C. 0.2% by weight of the radical polymerizable monomer was a polyfunctional monomer, and the weight average molecular weight of the resin composition in terms of polystyrene was 180,000.

(Preparation of Conductive Coating Composition) The conductive coating composition of Example 2 was obtained under the same conditions as in Example 1.

Example 3 (Synthesis of Resin Composition Used for Conductive Coating Composition) Under the same polymerization conditions as in Example 1, 320.0 g of toluene and Hardlen B-4000 (chlorinated polyolefin manufactured by Toyo Kasei Co., Ltd.) 300.0 g of a resin, a 30% solution of toluene), 206.4 g of methyl methacrylate, 90.0 g of tertiary butyl methacrylate, 3 g of methacrylic acid, and 0.6 g of ethylene glycol dimethacrylate were added and polymerized. A resin composition used for a paint was obtained.

In this example, the heating residue of the coating resin composition was 40.0%, the composition contained 23.0% by weight of chlorinated polyolefin resin in solid content, and the glass transition temperature of the acrylic component was 106 ° C. 0.2% by weight of the radical polymerizable monomer was a polyfunctional monomer, and the weight average molecular weight of the resin composition in terms of polystyrene was 200,000.

(Preparation of Conductive Coating Composition) A conductive coating composition of Example 3 was obtained under the same conditions as in Example 1.

Example 4 (Synthesis of Resin Composition Used for Conductive Coating Composition) Under the same polymerization conditions as in Example 1, 377.0 g of toluene and Hardlen B-4000 (chlorinated polyolefin manufactured by Toyo Kasei Co., Ltd.) Resin, 30% toluene solution) 70.0 g, methyl methacrylate 176.4 g, normal butyl methacrylate 120.0 g, methacrylic acid 3 g, ethylene glycol dimethacrylate 0.6 g were added and polymerized.
The resin composition used for the conductive paint was obtained.

In this example, the heating residue of the coating resin composition was 40.0%, the composition contained 6.5% by weight of chlorinated polyolefin resin in solid content, and the glass transition temperature of the acrylic component was 71 ° C. 0.2% by weight of the radical polymerizable monomer was a polyfunctional monomer, and the weight average molecular weight of the resin composition in terms of polystyrene was 180,000.

(Preparation of Conductive Coating Composition) A conductive coating composition of Example 4 was obtained under the same conditions as in Example 1.

[Comparative example]

Comparative Example 1 (Synthesis of Resin Composition Used for Conductive Coating Composition) Toluene 37 was obtained under the same polymerization conditions as in Example 1 except that the amount of Cadox B-75AW was 3.5 g each.
7.0 g, Hardlen B-4000 (chlorinated polyolefin resin, Toyo Kasei Co., Ltd., 30% toluene solution)
0 g, 204.0 g of methyl methacrylate, 90.0 g of tertiary butyl methacrylate, 3 g of methacrylic acid, and 3.0 g of ethylene glycol dimethacrylate were added and polymerized to obtain a resin composition used for the conductive paint of Comparative Example 1.

In this comparative example, the heating residue of the coating resin composition was 40.0%, the composition contained 6.5% by weight of chlorinated polyolefin resin in solid content, and the glass transition temperature of the acrylic component was 105 ° C. 3.0% by weight of the radical polymerizable monomer was a polyfunctional monomer, and the weight average molecular weight of the resin composition in terms of polystyrene was 1.5 million.

(Preparation of Conductive Coating Composition) Under the same conditions as in Example 1, a conductive coating composition of Comparative Example 1 was obtained.

Comparative Example 2 (Synthesis of Resin Composition Used for Conductive Coating Composition) Toluene 37 was prepared under the same polymerization conditions as in Example 1 except that the amount of each of Cadox B-75AW was 7.5 g.
7.0 g, Hardlen B-4000 (chlorinated polyolefin resin, 30% toluene solution, manufactured by Toyo Kasei Co., Ltd.)
0.0 g, 207.0 g of methyl methacrylate, 90.0 g of tertiary butyl methacrylate, 3 g of methacrylic acid
Was added and polymerized to obtain a resin composition used for the conductive paint of Comparative Example 2.

In this comparative example, the heating residue of the coating resin composition was 40.0%, the composition contained 6.5% by weight of chlorinated polyolefin resin in solid content, and the glass transition temperature of the acrylic component was 105 ° C. And no polyfunctional radical polymerizable monomers. The weight average molecular weight of the resin composition in terms of polystyrene was 30,000.

(Preparation of Conductive Coating Composition) Under the same conditions as in Example 1, a conductive coating composition of Comparative Example 2 was obtained.

Comparative Example 3 (Synthesis of Resin Composition Used for Conductive Coating Composition) Under the same polymerization conditions as in Example 1, 390.0 g of toluene and Hardlen B-4000 (chlorinated polyolefin manufactured by Toyo Kasei Co., Ltd.) (Resin, 30% solution in toluene) 15.0 g, 206.4 g of methyl methacrylate, 90.0 g of tertiary butyl methacrylate, 3 g of methacrylic acid, 0.6 g of ethylene glycol dimethacrylate, and polymerized. A resin composition used for a paint was obtained.

In this comparative example, the heating residue of the coating resin composition was 40.0%, the solid component contained 1.5% by weight of a chlorinated polyolefin resin, and the glass transition temperature of the acrylic component was 105 ° C. 0.2% by weight of the radical polymerizable monomer was a polyfunctional monomer, and the weight average molecular weight of the resin composition in terms of polystyrene was 180,000.

(Preparation of Conductive Coating Composition) A conductive coating composition of Comparative Example 3 was obtained under the same conditions as in Example 1.

Comparative Example 4 (Synthesis of Resin Composition Used for Conductive Coating Composition) Under the same polymerization conditions as in Example 1, Hardlen B-4000 (a chlorinated polyolefin resin manufactured by Toyo Kasei Co., Ltd., toluene 3
(0% solution) 500.0 g, methyl methacrylate 34.4
g, 15.0 g of tertiary butyl methacrylate, 0.5 g of methacrylic acid, and 0.3 g of ethylene glycol dimethacrylate were added and polymerized to obtain a resin composition used for the conductive paint of Comparative Example 4.

In this comparative example, the heating residue of the resin composition for a paint was 36.4%, the chlorinated polyolefin resin was contained at a solid content of 75.0% by weight, and the glass transition temperature of the acrylic component was 105 ° C. 0.6 of the radical polymerizable monomer
The weight% was a polyfunctional monomer, and the weight average molecular weight in terms of polystyrene of the resin composition was 150,000.

(Preparation of Conductive Coating Composition) 33 g of the resin composition of Comparative Example 4 and Carponyl 255 (INCO Corporation)
35 g of nickel powder (manufactured by Nickel Powder), 17 g of toluene, and 15 g of xylene were mixed by disperser dispersion to obtain a conductive coating composition of Comparative Example 4.

Comparative Example 5 (Synthesis of Resin Composition Used for Conductive Coating Composition) Under the same polymerization conditions as in Example 1, 377.0 g of toluene and Hardlen B-4000 (chlorinated polyolefin manufactured by Toyo Kasei Co., Ltd.) (Resin, 30% toluene solution) 70.0 g, methyl methacrylate 86.4 g, normal butyl methacrylate 210.0 g, methacrylic acid 3 g, ethylene glycol dimethacrylate 0.6 g were added and polymerized to obtain a conductive paint of Comparative Example 5. A resin composition to be used was obtained.

In this comparative example, the heating residue of the coating resin composition was 40.0%, the composition contained 6.5% by weight of chlorinated polyolefin resin in solid content, and the glass transition temperature of the acrylic component was 45 ° C. 0.2% by weight of the radical polymerizable monomer was a polyfunctional monomer, and the weight average molecular weight of the resin composition in terms of polystyrene was 200,000.

(Preparation of Conductive Coating Composition) The conductive coating composition of Comparative Example 5 was obtained under the same conditions as in Example 1.

[Evaluation method of conductive paint]

Preparation of Paint and Drying of Paint The resin composition for paint obtained in the above Examples and Comparative Examples was diluted with a mixed solvent composed of 50% by weight of toluene, 30% by weight of ethyl acetate and 20% by weight of xylene in a polypropylene molding material. The coating was performed uniformly by air spray coating so that the dry film thickness became 30 μm. After the completion of the air spray, the mixture was allowed to stand for 5 minutes, and dried in a box-type drying oven at 80 ° C. for 30 minutes. After forced drying, 5 indoors at 25 ° C
Each test was performed after standing for a day. The test results are as shown in Table 1.

Coating film test items and evaluation method Adhesion test: 1 mm x 1 mm x 100 square cuts,
The adhesion state after the cellophane tape peeling test was relatively evaluated. Moisture resistance adhesion test: 240 in a constant temperature bath at 65 ° C and 95 RH%
After standing for 1 hour, 1mm x 1mm x 100 grid cuts,
The adhesion state after the cellophane tape peeling test was relatively evaluated. Storage stability: When 1 kg of the test paint was sealed and stored in a room at 25 ° C, the separation of paint components during storage was relatively evaluated. Painting workability: Workability when spray coating the test paint was relatively evaluated. Surface conductivity test: Electric resistance value on the coating film surface. Electromagnetic shielding suitability: The suitability of using the test paint as an electromagnetic shielding paint was relatively evaluated.

Test evaluation criteria ◎: extremely good ：: good △: slightly poor but usable range ×: bad

【The invention's effect】

As described above, in the present invention, although it is possible to directly apply to a polyolefin-based plastic substrate that has not been subjected to a physical or chemical pretreatment step, adhesion, solvent resistance, The present invention has made it possible to provide a conductive coating composition which is excellent in coating film hardness and storage stability and has a low surface specific electric resistance value.

Further, the conductive coating composition of the present invention is particularly suitable as a coating for electromagnetic shielding, and has made it possible to provide a coating for electromagnetic shielding excellent in cost and a coated article using the same.

[Table 1]

Claims (4)

[Claims] 1. Radical polymerization of 2 to 60 parts by weight of a chlorinated polyolefin resin having a chlorine content of 50% by weight or less and 98 to 40 parts by weight of at least one or more radical polymerizable monomers together with an organic solvent as required. Conductive coating composition obtained by mixing a resin composition obtained by the above method with a metal powder. 2. The conductive polymer according to claim 1, wherein 0.05% to 10.0% by weight of the radical polymerizable monomer according to claim 1 is a polyfunctional radical polymerizable monomer. Paint composition. 3. The conductive coating composition according to claim 1, wherein the radical-polymerizable monomer has a glass transition temperature of 50 ° C. or higher during radical polymerization. 4. The resin composition used in the conductive coating composition according to claim 1, wherein the resin composition has a polystyrene equivalent weight average molecular weight of 50,000 to 1,000,000. Conductive paint composition.