Continuous process for producing a metal clad laminate

Claim 1

In a continuous process for producing a metal clad laminate comprising the steps of impregnating a plurality of fibrous substrates with a curable liquid unsaturated polyester resin, combining the resin-impregnated substrate together and simultaneously laminating a metal foil onto at least one side of the combined substrates, and curing the resulting laminate, the improvement comprising the steps of: (a) continuously applying a composition consisting essentially of a curable liquid epoxy resin adhesive containing an amine or amide type curing agent onto the side of said metal foil which faces the combined substrates in the finished laminate to form a film; (b) interposing an additional layer of a compound having a copolymerizable unsaturated bond and an epoxy group in the molecule at the interface between the resin-impregnated substrate and the adhesive film; and (c) continuously heating said film in situ to remove solvent and gas bubbles present in the adhesive film and to precure said film sufficiently to prevent the adverse effects of low molecular weight components diffusing from the curable resin layer into the adhesive layer immediately prior continuously laminating said metal foil.