JPS6244031B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention is applicable to automobiles, airplane bodies, home appliances,
Used for adhesive sealing of metal parts of various devices,
The present invention relates to a conductive resin composition for seals that has excellent oil surface adhesion, as well as spot weldability and electrodeposition coating properties.

Conventionally, metal structures have been adhesively sealed with various rubber or resin compositions before welding, painting, or other processes. However, these compositions are originally insulators;
When used for sealing, the electrodeposited liquid did not adhere to the surface of the resin seal layer and the metal plate did not adhere well to the surface of the metal plate, resulting in rust formation. To prevent this, adhesive seals are made using rubber compositions mixed with metal powder, etc., but they have poor heat resistance and durability.
Furthermore, when used on a member with an oil film such as an untreated steel plate, there were problems such as poor adhesion, poor pasting workability, and seal leakage.

As a result of various studies to improve the shortcomings of the prior art, the inventors found that by blending a curing agent and a conductive filler into a liquid or semi-solid epoxy resin having a long alkyl main chain, I learned that I can avoid the problem. It has also been found that the sealing properties can be further improved by further adding a foaming agent to the above formulation.

That is, the present invention provides a conductive sealing material with excellent oil surface adhesion, which is prepared by adding a curing agent and a conductive filler to a liquid or semi-solid epoxy resin having a long alkyl main chain having 5 to 50 carbon atoms. The first invention relates to a conductive resin composition, and the second invention relates to a foamable conductive resin composition for seals having excellent oil surface adhesion, which is obtained by further incorporating a foaming agent into the above-mentioned formulation. It is what it is.

The electrically conductive resin composition for sealing obtained by the present invention has good initial adhesion even to oil-film steel plate surfaces, thereby improving sealing workability and avoiding seal leakage. In addition, by heating and curing the paint during the baking process, etc., a sealing layer with excellent mechanical strength, heat resistance, and durability can be formed.This sealing layer has good spot weldability and electrodeposition coating properties, so it can be used at the interface with the metal plate. It does not cause rust and has an excellent appearance. Further, when a foaming agent is added, in addition to the above-mentioned properties, a sealing layer having a foamed structure is provided, so that the adhesive sealing properties and sealing properties are further improved.

The liquid or semi-solid epoxy resin having a long alkyl main chain with 5 to 50 carbon atoms used in this invention has good compatibility with oil and fat because the alkyl chain is a hydrophobic group, and has good compatibility with oil film steel sheets. These resins contribute to improving initial adhesion, and examples of such resins include epoxy resins produced by reacting epichlorohydrin with polymers such as polyethylene glycol, polypropylene glycol, and α/ω-glycol, a block copolymer of ethylene oxide and propylene oxide. ; Epoxy resins derived from the reaction of S-ylide with the carbonyl group of polyvinyl chloride, polyacrolein, or polyvinyl ketone; Epoxy resins derived from dimer acid, trimer acid, unsaturated higher fatty acids or esters thereof, and the like.

Among the above epoxy resins, epoxy resins derived from long chain dimer acids having 10 to 20 carbon atoms are preferably used, and examples include epoxy resins derived from linoleic acid dimer and epichlorohydrin. When these resins are used, particularly good results can be obtained in terms of adhesion to oil surfaces, and conductive resin compositions for seals having excellent water resistance, chemical resistance, etc. can be obtained.

Note that it is possible to use an ordinary epoxy resin together with the above-mentioned epoxy resin having a long alkyl main chain in a proportion of 50% by weight or less of the total.

The curing agent for curing the epoxy resin may be any ordinary curing agent that exhibits a curing effect when heated, such as dicyandiamide, 4,4'-diaminodiphenylsulfone, and 2-n-peptadecylimidazole. Imidazole derivatives, isophthalic acid dihydrazide, N·N-dialkyl urea derivatives, N·N-dialkylthiourea derivatives, etc. are used. The amount used may be generally 1 to 15 parts by weight per 100 parts by weight of the epoxy resin.

In this invention, it is important to mix a conductive filler, and such fillers include metal powders such as silver, palladium, copper, aluminum, iron, and nickel, and metals such as carbon black and graphite. Examples include inorganic substances other than powder. The amount used varies depending on the type, shape, particle size, etc. of the conductive filler, but it is usually used at a ratio of 10 to 700 parts by weight per 100 parts by weight of the epoxy resin.

In this invention, in order to obtain a foamable conductive resin composition for seals, a foaming agent is used in addition to the above-mentioned components. By blending this foaming agent, the resin foams as it heats and hardens, forming a foam layer at the sealing site, resulting in more complete sealing.

Such blowing agents generally include azo dicarbonate, azo compounds such as azobisisobutyronitrile, nitroso compounds such as dinitrosopentamethylenetetramine, paratoluenesulfonylhydrazide, 4.4 A wide range of hydrazide compounds such as '-oxybisbenzenesulfonyl hydrazide can be used. These may be used alone or in combination, if necessary together with foaming aids such as urea and metal salts of carboxylic acids.
The proportion of such blowing agents (or foaming aids) is generally 1 to 1 to 100 parts by weight of resin.
It is preferably about 25 parts by weight so that foaming occurs at the curing temperature and the foaming ratio after heating is practically about 2 to 30 times.

In addition to the above-mentioned components, various compounding agents can be added to the conductive resin composition for seals and the foamable conductive resin composition for seals in this invention, as necessary. For example, stabilizers such as phenyl-β-naphthylamine, diphenyl-P-phenylenediamine, ditertiarybutyl-4-methylphenol, paraphenylphenol, calcium stearate, and dilaurylthiodipropionate are used to further improve heat resistance. and anti-aging agents, diesters, ester gums, alkyd resins, and coumaron resins to further improve adhesion; clay, talc, calcium carbonate, silica, and silica to prevent compositions from sagging and reduce costs.
Fillers such as barium carbonate and asbestos can be added respectively. Other coloring agents and the like may also be added. The blending amount of these components may be approximately 5 to 300 parts by weight per 100 parts by weight of the epoxy resin.

In order to obtain the conductive resin composition for seals and the foamable conductive resin composition for seals of the present invention, a curing agent and a conductive filler are added to the epoxy resin, and when the epoxy resin is made foamable, it is further foamed. and various other additives as necessary,
Mixing may be carried out at room temperature or at a temperature at which curing or foaming does not occur (although slight curing or foaming may occur) using a mixing stirrer, various kneaders, two or three mixing rolls, etc.

The conductive resin composition for seals and the foamable conductive resin composition for seals according to the present invention can be applied directly to the sealing area in liquid or semi-solid form, and can also be applied to cloths such as glass, polyester, non-woven fabrics, etc. Alternatively, it can be applied to various films in the form of a sheet and used as a sheet-like product.

The present invention will be specifically explained below using examples. Parts in the examples are parts by weight.

Example 1 80 parts of Epicoat #871 (dimer acid-modified epoxy resin manufactured by Yuka Shell Co., Ltd.) and 20 parts of Epicoat #1001 (bisphenol A type solid epoxy resin manufactured by Yuka Shell Co., Ltd.) were melted and mixed in a melting pot to form a viscosity. A thick composition was obtained. Add 5 parts of dicyandiamide (epoxy resin curing agent manufactured by Nippon Carbide Co., Ltd.) to 100 parts of this composition.
5 parts, Kyuazol 2MZ-AZINE (epoxy resin curing agent manufactured by Shikoku Kasei Co., Ltd.), graphite powder
A resin composition is obtained by mixing 100 parts of asbestos powder and 3 parts of asbestos powder, and kneading it with a normal mixing roll. This is formed into a sheet shape on a film separator using a direct press to form a sheet with a thickness of 0.5 mm or more. A conductive resin sheet for sealing in an uncured state was obtained.

This resin sheet was inserted into the gap between two oily steel plates and sealed, followed by electrodeposition coating and acrylic baking coating. Heating: 180℃ x 20 minutes, 160℃
×It was hot in 30 minutes. In the heating process, the resin sheet hardened to seal the gap between the steel plates well, and the electrodeposition paint also adhered to the resin surface, resulting in good interfacial coating properties.

Example 2 To 100 parts of the viscous composition used in Example 1, 5 parts of dicyandiamide (same as in Example 1), 5 parts of Kyuazol 2MZ-AZINE (mentioned above), 100 parts of graphite powder, and Neocellvon P were added. Two parts of #1000 (a blowing agent manufactured by Eiwa Kasei Co., Ltd.) and three parts of asbestos powder were mixed and kneaded and formed into a sheet in the same manner as in Example 1 to produce a sheet with a thickness of 0.3 mm. Insert this sheet-like material between two oily steel plates,
Performed spot welding. After that, electrodeposition painting and acrylic painting were performed. Due to the heating during both coatings, the resin hardened and foamed, resulting in a very good seal between the two steel plates. Since the seal part has a foamed structure, the sealing properties are good, and the paintability of the interface is also good, and the occurrence of rust etc. is prevented.

Claims (1)

[Claims] 1. A seal with excellent oil surface adhesion made by adding a curing agent and a conductive filler to a liquid or semi-solid epoxy resin having a long alkyl main chain with 5 to 50 carbon atoms. Conductive resin composition. 2 A liquid or semi-solid epoxy resin having a long alkyl main chain with 5 to 50 carbon atoms has 10 to 20 carbon atoms.
The conductive resin composition for sealing having excellent oil surface adhesion according to claim 1, which is derived from a long chain dimer acid. 3. The conductive resin composition for sealing having excellent oil surface adhesion according to claim 1 or 2, wherein the conductive filler is a metal powder. 4. The conductive resin composition for seals having excellent oil surface adhesion according to claim 1 or 2, wherein the conductive filler is an inorganic substance other than metal powder such as carbon black or graphite. 5 For foaming seals with excellent oil surface adhesion, made by adding a curing agent, a conductive filler, and a foaming agent to a liquid or semi-solid epoxy resin having a long alkyl main chain with 5 to 50 carbon atoms. Conductive resin composition.