Method of providing a copper article with a surface layer promoting the adherence of adhesives

摘要

An adhesive comprises 80 parts by weight of copolymer (1:3) of acrylonitrile and butadiene, 100 parts by weight of cresolformaldehyde resin and 15 parts by weight of formic acid the mixture being dissolved in 800 parts by weight of methyl ethyl ketone.ALSO:In order to effect an adhesive bond between a copper body and another article a surface area of said copper body is covered with a layer which is the result of a reaction between the surface of the copper body and an organic nitrogen compound which splits off ammonia at an elevated temperature and is formed by decomposing said compound by heating while in contact with the surface area of the copper body. The term "copper body" includes copper plated bodies and also bodies of alloys containing a substantial proportion of copper. Compounds used for treating the copper are urea, formamide and hexamethylenetetramine to which is added a wetting agent, e.g. triethanolamine or a sulphonic acid salt of an aliphatic hydrocarbon and an oxidizing agent, e.g. 0.5% ammonium persulphate. In an example a copper sheet after moistening with the treatment solution is heated to a temperature of 140-160 DEG C. in a hot air furnace or by contact heating for 5 minutes. The treated surface of the sheet is covered with a layer of adhesive consisting of 80 parts by weight of copolymer of acrylonitrile and butadiene, 100 parts by weight of cresolformaldehyde resin and 15 parts by weight of formic acid by dissolving this mixture in 800 parts by weight of methyl ethyl ketone and spreading it on the sheet. The solvent is evaporated by heating at 130 DEG C. for 30 minutes. The treated sheet is laid on top of a stack of sheets of paper impregnated with a hardenable condensate of the phenolaldehyde type. The stack is transferred to a press and heated to 160 DEG C. under a pressure of 60 atmospheres for 30 minutes to bond the copper to the resin-impregnated paper laminate.