JP3144300B2 - Conductive composition for forming conductive coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paint for forming a conductive circuit on a printed circuit board, a paint for electromagnetic wave shielding, and a conductive composition used as a conductive adhesive, and in particular, to screen printing on a circuit board. The present invention relates to a conductive composition capable of forming a conductive coating film having excellent conductivity and adhesion by drying or heating and curing after being applied by a method such as that described above.

[0002]

2. Description of the Related Art A conductive composition for forming a conductive coating film is obtained by dispersing a conductive powder in a solution of a resin binder made of a thermosetting resin or a thermoplastic resin. Conventionally, silver powder has been widely used as the conductive powder. Recently, however, base metal powders such as copper powder and nickel powder, which are inexpensive, have excellent conductivity and do not cause migration, have been attracting attention as an alternative material. However, base metal powders, particularly copper powders, have a drawback that they are easily oxidized, and lose their conductivity during storage or after curing, and thus it is difficult to maintain high conductivity for a long time. Particularly, the adhesiveness, curability, and heat resistance are excellent, and the epoxy resin commonly used as a binder resin in a silver-based composition tends to promote the oxidation of the base metal filler. It cannot be used as a binder resin for the conductive composition used. On the other hand, a resin binder having an antioxidant effect, such as a phenol resin or a melamine resin, has insufficient adhesiveness particularly to a copper foil of a printed circuit board. Therefore, there is an attempt to mix about 10% of an epoxy resin for the purpose of providing an adhesive function, but a decrease in conductivity is inevitable. Also a method of preventing a decrease in conductivity by adding an antioxidant,
Various attempts have been made. For example, Japanese Patent Publication No. 1-35025 discloses that hydroxybenzenes such as hydroquinone, catechol and pyrogallol are blended to prevent oxidation of the copper powder surface. In addition, 2-481
No. 83 describes the addition of aliphatic amines such as triethanolamine and ethylenediamine. However, hydroxybenzene-based compounds have a small effect and are not enough to prevent copper oxidation alone, and are often used in combination with amines. Aliphatic amines have a large antioxidant effect, but have a drawback of high reactivity with an epoxy resin, so that the coating material is significantly thickened or hardened. The present inventors have previously found that sulfonamides have a remarkable antioxidant effect and can be blended into an epoxy resin-based composition, and have filed a patent application (Japanese Patent Application No. Hei 5 (1993) -197, filed on Jan. 19, 1997).
−345719), and further studied to complete the present invention.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to effectively prevent the oxidation of a conductive powder without impairing paint suitability and printability, not to reduce the conductivity for a long period of time, and to improve adhesion. It is an object of the present invention to provide a conductive composition capable of forming a conductive coating film excellent in the above.

[0004]

Means for Solving the Problems The present invention provides: (1) (A) a conductive powder, (B) a binder resin,
(C) a sulfonylcarboximide represented by the formula 1,
A conductive film for forming a conductive film containing one or more selected from sulfonylcarboxylic acid amides represented by the formula 2 and derivatives thereof and, if necessary, (D) a solvent ;
Gender composition. Equation 1

[0005]

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(Where R ₁ represents an aryl group, an alkyl group or an alkenyl group)

[0007]

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(However, R ₂ and R ₃ represent an aryl group, an alkyl group or an alkenyl group.) The amount of the sulfonylcarboxylic acid imide, the sulfonylcarboxylic acid amide and the derivative thereof is not more than 10%.
1 to 5 parts by weight in total with respect to 0 parts by weight;
13. The conductive composition for forming a conductive coating film according to the above item. 3. 3. The conductive film for forming a conductive film according to item 1 or 2, wherein the derivative of the sulfonylcarboxylic acid imide or the sulfonylcarboxylic acid amide is an alkyl-substituted product, a carboxylic acid derivative, an alcohol derivative or an ether derivative.
Gender composition. 4. Item 1. The conductive powder is one or more selected from copper, nickel, silver, iron, and cobalt metal powders, alloy powders containing these metals, and powders coated with these metals or alloys. 4. The conductive composition for forming a conductive coating film according to any one of items 3 to 3. 5. The conductive powder for forming a conductive coating film according to item 4, wherein the conductive powder is a powder to which one or more selected from a noble metal powder, a noble metal alloy powder, and a powder coated with a noble metal or an alloy are added . Composition. 6. The binder resin is a resin containing an epoxy resin,
Item 6. A conductive coating film according to any one of Items 1 to 5
A conductive composition for formation . 7. Item 7. The conductive composition for forming a conductive coating film according to any one of Items 1 to 6, wherein the amount of the binder resin is 1 to 60 parts by weight based on 100 parts by weight of the conductive powder. "
About.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The sulfonylcarboxylic imide used in the present invention is an imide having a structure in which one of the acyl groups of an ordinary imide is substituted with a sulfonyl group.
And sulfobenzimide. Examples of the sulfonylcarboxylic acid amide include N-octadecanoylbenzenesulfonylamide, N-octadecanoyltoluenesulfonylamide, and N-laurylbenzenesulfonylamide. As the derivative of the sulfonylcarboxylic acid imide and the sulfonylcarboxylic acid amide, a compound in which H of NH is substituted with an alkyl group, an ether such as a carboxylic acid, an alcohol, or a polyalkylene glycol is used. Two or more of these sulfonylcarboxylic imides or sulfonylcarboxylic amides may be used in combination. Further, other antioxidants such as sulfonamides can be used in combination.

The amount of the sulfonylcarboxylic acid imides and sulfonylcarboxylic acid amides to be added is suitably 0.01 to 5 parts by weight based on 100 parts by weight of the conductive powder. 0.0
If it is less than 1 part by weight, the antioxidant effect is weak, and if it exceeds 5 parts by weight, the adhesion and strength of the coating film are reduced. As the binder resin, various thermosetting resins and thermoplastic resins commonly used are used. For example, epoxy resin, phenol resin, melamine resin, polyester resin, alkyd resin, acrylic resin, methacrylic resin, butyral resin,
Examples thereof include a vinyl resin, cellulose and derivatives thereof, but it is preferable to contain an epoxy resin from the viewpoint of adhesiveness.
Further, two or more resins may be used as a mixture.

The mixing ratio of the binder resin is as follows.
About 1 to 60 parts by weight is desirable for 00 parts by weight. 1
When the amount is less than the weight part, the printability is impaired, the adhesiveness is reduced, and the resistance value is increased. If it exceeds 60 parts by weight, the resistance value increases.

As the conductive powder, copper, nickel, iron,
One or more of base metal powders such as cobalt and noble metal powders such as silver, palladium, and gold are used. Alloy powders containing these metals, for example, silver-copper alloy, silver-
Powders of a palladium-copper alloy, nickel silver, phosphor bronze, brass, solder, or the like, or powders coated with these metals or alloys may be used. These conductive powders can be used after being surface-treated with various fatty acids, coupling agents, and the like by a conventional method.

The composition may further contain, if necessary, a solvent which is generally used for controlling the suitability for coating and the like. In addition, other additives conventionally added to the conductive composition, such as a surfactant, an antifoaming agent, a plasticizer, a thixotropic agent, and a dispersant, may be appropriately added. These components are mixed as usual and kneaded with a roll mill or the like to obtain a conductive composition.

[0014]

【Example】

Example 1 Electrolytic copper powder 100 parts by weight 50% ethyl carbitol solution of phenol resin 24
Parts by weight Epoxy resin 8 parts by weight o-sulfobenzimide 1 part by weight The above components were mixed and kneaded with a three-roll mill to produce a conductive composition. Each of the obtained compositions was applied on a copper foil / glass epoxy resin substrate in a square pattern of 10 mm × 10 mm, and cured at a temperature of 160 ° C. for 30 minutes. The specific resistance of the cured coating film was 1 × 10 ⁻⁴ Ωcm.

Example 2 A conductive composition was produced in the same manner as in Example 1 except that the amount of o-sulfobenzimide was changed to 0.1 part by weight. The obtained composition was similarly applied on a substrate and cured. The specific resistance of the cured coating film was 1 × 10 ⁻⁴ Ωcm.

Example 3 A conductive composition was produced in the same manner as in Example 1 except that the amount of o-sulfobenzimide was changed to 2 parts by weight. The obtained composition was similarly applied on a substrate and cured. The specific resistance of the cured coating film was 1 × 10 ⁻⁴ Ωcm.

Example 4 A conductive composition was obtained in the same manner as in Example 1 except that 1 part by weight of N-octadecanoylbenzenesulfonylamide was used instead of o-sulfobenzimide. The composition was similarly applied on a substrate and cured. The specific resistance of the cured coating film was 1.5 × 10 ⁻⁴ Ωcm.

Comparative Example 1 A conductive composition was obtained in the same manner as in Example 1 except that o-sulfobenzimide was not added. Similarly, the composition was applied to a substrate and cured, and the specific resistance of the cured coating film was measured.

[0019]

According to the conductive composition for forming a conductive coating film of the present invention, the oxidation of the conductive powder can be effectively prevented by blending a sulfonylcarboxylic imide or a sulfonylcarboxylic amide to prevent the conductive powder from being stored. Also, the conductive powder is not oxidized even after curing and has excellent initial conductivity, and a conductive coating film capable of maintaining high conductivity for a long period of time is formed.
Further, even when an epoxy resin is used as the binder, the conductivity does not decrease, so that it is possible to manufacture a conductive coating film having a high adhesion strength to a substrate, particularly a copper foil.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C09D 5/24

Claims (7)

(57) [Claims] 1. One kind selected from (A) a conductive powder, (B) a binder resin, (C) a sulfonylcarboximide represented by the formula 1, a sulfonylcarboxamide represented by the formula 2, and a derivative thereof. Or for forming a conductive coating film containing two or more kinds and, if necessary, a solvent (D)
Conductive composition. Formula 1 (Where R ₁ represents an aryl group, an alkyl group or an alkenyl group) (However, R ₂ and R ₃ represent an aryl group, an alkyl group or an alkenyl group.) 2. The composition according to claim 1, wherein the compounding amount of the sulfonylcarboxylic acid imide, the sulfonylcarboxylic acid amide and the derivative thereof is 0.01 to 5 parts by weight in total with respect to 100 parts by weight of the conductive powder. A conductive composition for forming a conductive coating film . 3. The conductive material according to claim 1, wherein the derivative of the sulfonylcarboxylic imide and the sulfonylcarboxylic amide is an alkyl-substituted product, a carboxylic acid derivative, an alcohol derivative or an ether derivative.
Conductive composition for coating film formation . 4. One or more conductive powders selected from copper, nickel, silver, iron, and cobalt metal powders, alloy powders containing these metals, and powders coated with these metals or alloys. The conductive composition for forming a conductive coating film according to any one of claims 1 to 3, which is: 5. The conductive powder is a powder to which one or more selected from a noble metal powder, a noble metal alloy powder, and a powder coated with a noble metal or an alloy are added.
4. The conductive composition for forming a conductive coating film according to 1.). 6. The conductive composition for forming a conductive coating film according to claim 1, wherein the binder resin is a resin containing an epoxy resin. 7. A method according to claim 1, wherein the amount of the binder resin is 100
The conductive composition for forming a conductive coating film according to any one of claims 1 to 6, wherein the amount is 1 to 60 parts by weight based on part by weight.