JPS59124972A - Conductive resin composition for seal excellent in adhesion to oily surface - Google Patents

Abstract

PURPOSE:To provide a conductive rsin compsn. well suited for adhesive seal of metallic parts of automobiles, etc., excellent in adhesion to oily surfaces, by incorporating curing agents and conductive fillers with liq. or semi-solid epoxy resins having the main chain of long-chain alkyl groups. CONSTITUTION:A liq. or semi-solid epoxy resin having the main chain of long- chain alkyl groups prepd. by such a method as derivation from 10-20C long- chain dimer acids, a curing agent (e.g., dicyandiamide or 4,4'-diaminodiphenyl sulfone), and a conductive filler (e.g., iron powder, carbon black, or graphite), and further a foaming agent such as azobisisobutyronitrile or dinitrosopentamethylenetetramine (in the preparation of foamable conductive resin compds. for seal) are incorporated to yield the intended conductive resin compsn. for seal excellent in adhesion to oily surfaces.

Description

[Detailed Description of the Invention] This invention is used for adhesive sealing of metal parts of automobiles, airplane bodies, home appliances, and various devices, and has excellent oil surface adhesion and is easy to spot weld and electrodeposit. The present invention relates to a conductive wood one-finger composition for seals.

Conventionally, adhesive soles are made using various combs or resin compositions before processes such as metal horizontal drawing, welding, and painting.

However, these compositions are originally insulators, and when used for sealing, the electrodeposition liquid will adhere to them, resulting in poor coating adhesion and rust formation at the interface between the resin sealing layer and the metal plate (in some cases). To prevent this, adhesive sealing is performed using a rubber composition mixed with metal powder, etc., but it has poor heat resistance and durability, and is not used on parts with oil films such as untreated steel plates. In some cases, the adhesion is poor and the workability of pasting is poor,
There were some inconveniences such as seal leakage.

As a result of various studies in order to improve the drawbacks of the prior art, the present inventors discovered that by blending a curing agent and a conductive photonic agent 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 resin composition for seals with excellent oil surface adhesion, which is prepared by adding a curing agent and a conductive photonic agent to a liquid or semi-solid epoxy resin having a long alkyl main chain. and a second invention relating to a foamable conductive resin composition for seals with excellent oil surface adhesion, which is obtained by further blending a foaming agent into the above-mentioned formulation. .

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 process, it is possible to form a sealing layer with excellent mechanical strength, heat resistance, and durability.This sealing layer has good spot weldability and electrodeposition coating properties, so it is compatible with metal plates. Rust does not occur at the interface, and the appearance becomes dull. 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 used in this invention has good compatibility with oils and fats because the alkyl chain is a hydrophobic group, and is effective in improving initial adhesion to oil film steel sheets. Contribute. The long alkyl main chain has about 5 to 50 carbon atoms. Such resins include epoxy resins produced by reacting epichlorohydrin with polymers such as polyethylene glycol, polypropylene glycol, and α/ω-glycol, which is a block copolymer of ethylene oxide and propylene oxide; polyvinyl chloride, polyacrolein, and polyvinyl ketone. Epoxy resins derived from the reaction of a carbonyl group and S-ylide; epoxy resins derived from dimer acids, trimer acids, unsaturated primary fatty acids or esters thereof, and the like.

Among the above epoxy resins, epoxy resins derived from long-chain dimer acids having a carbon number of 10 to 2 degrees are preferably used, such as 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 conventional curing agent that exhibits curing action upon heating, such as dicyandiamide, 4,4'-diaminodiphenylsulfone, 2-n-peptadesiourea derivatives, and the like. 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 optical filler, and such fillers include metal powders such as silver, palladium, copper, aluminum, iron, nickel, etc.
Examples include inorganic substances other than metal powders such as carbon black and graphite.

The amount used varies depending on the type, shape, particle size, etc. of the conductive photonic agent, but it is usually 100% of the epoxy resin and 1% of the heavy IC part.
It is used in a proportion of 0 to 700 parts by weight.

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 azodicarbonate, aso compounds such as azobisisobutyronitrile, nitroso compounds such as dinitrosopentamethylenetetramine, paratoluenesulfonyl hydrazide,
Hydrazide compounds such as 4,4'-oxybisbenzenesulfonylhydrazide can be widely used.

These may be used alone or in combination, optionally 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 25 parts by weight per 100 parts by weight of the resin, so that foaming occurs at the curing temperature and the foaming ratio after heating increases. Practically speaking, it is preferable that the amount is about 2 to 30 times larger.

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 according to the present invention, if necessary.

For example, phenyl-β-
Naphthylamine, diphenyl-P-phenylenediamine, ditertiaryphthyl-4-methylphenol, paraphenylphenol, calcium stearate, dilau 1
Stabilizers and anti-aging agents such as northiodipropionate are added, diesters, ester gums, alkyd resins, and coumaron resins are added to improve adhesion, and clay is added to prevent compositions from sagging and reduce costs. Fillers such as talc, calcium carbonate, silica, barium carbonate, asbestos, etc. can be added. A fine neck coloring agent or the like may be added. The blending amount of these components may be about 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 photonic agent are added to the epoxy resin, and when the resin composition is made foamable, further added. Add a foaming agent and other various additives as necessary, and mix at room temperature or at a temperature that does not cause curing or foaming (although it may occur slightly) in a stirring pot, various kneaders, two or It may be mixed using a three-roll mixing roll or the like.

The conductive resin composition for seals and the foamable conductive resin composition for seals according to the present invention can be used in liquid or semi-solid form by being applied directly to the seal area, and can also be used with cloth made of glass, polyester, etc. It can be used as a sheet by coating it on non-woven fabric or various films.

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

Examples: 80 parts of Epi2 1-Hai 871 (dimer acid-modified epoxy resin manufactured by Yuka Shell Co., Ltd.), Epicoat: l-1=1001
(Bisphenol A type solid epoxy resin manufactured by Yuka Shell Co., Ltd.) 20 parts were melted and mixed in a melting pot to obtain a viscous composition. 100 parts of this composition, 5 parts of dicyandiamide (epoxy resin curing agent manufactured by Nippon Carbide Co., Ltd.), and 2M of Curesol.
Z-AZINE (Epoxy resin curing agent manufactured by Shikoku Kasei Co., Ltd.)
5 parts of graphite powder, 100 parts of graphite powder, and 3 parts of asbestos powder were mixed and kneaded with a normal mixing roll to obtain a resin ready-made product, which was then formed into a sheet on a film separator using a direct pressure press. An uncured conductive resin sheet for sealing having a thickness of 0.5 mm 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 was at 180℃ for 20 minutes each.

The temperature was 160°C for 30 minutes. The resin sheet hardened during the heating process, sealing the gap between the steel plates well, and the electrodeposition paint also adhered to the resin surface, giving 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) and 2 parts of Curesol were added.
MZ-AZINE (mentioned above) 5 parts, graphite powder 1
00 parts, Neocellvon P#1000 (a foaming agent manufactured by Hydraulic Chemical Co., Ltd.) 2 parts, and 3 parts of asbestos powder were blended, and mixed and formed into a sheet in the same manner as in Example 1 to produce a sheet with a thickness of 0.3 mm. did. This sheet-like material was inserted between two steel plates to which oil was attached, and spot welding was performed. After that, electrodeposition painting and acrylic painting were performed. Due to the heating during both coatings, the resin hardened and foamed, creating a very good tight 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.

Patent applicant: Nitto Electric Industry Co., Ltd.

Claims (5)

[Claims] (1) A conductive resin composition for seals that has adhesion to oil surfaces and is prepared by adding a curing agent, a conductive agent, and an external light-proofing agent to a liquid or semi-solid epoxy resin having a long alkyl main chain. (2) The Uramen Neko according to claim (1), wherein the liquid or semi-solid epoxy resin having a long-chain alkyl main chain is derived from a long-chain dimer acid having 10 to 20 carbon atoms. A conductive resin composition for seals with excellent properties. (3) A conductive resin composition for a seal having excellent curved surface adhesion according to claim (1) or (2), wherein the conductive filler is a metal powder. (4) A conductive seal with excellent oil surface adhesion according to claim (1) or (2), wherein the conductive filler is made of an inorganic substance other than metal powder such as carphone flank or graphite. resin composition. (5) A foamable conductive resin composition for seals that has adhesive properties on oil surfaces and is 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. thing.