Patent GB-766813-A (GB)
Title: Improvements in the bonding of polythene to metals
Inventor: JONES EDWARD RICHARD STANLEY
IPC: H01B17/42
Filed: 1954-03-05
Abstract: Polythene is united to a metal surface by forming a thin coating of polythene on the metal surface, oxidizing it by baking above its melting point, and then bonding the main body of the polythene, by heat, to the thin coating of oxidized polythene. Several thin layers of polythene, oxidized to successively decreasing extents, may be used.  The thin coating of polythene may contain an oxidation catalyst, e.g. ditertiary butyl peroxide, tertiary butyl hydroperoxide, and certain metal salts, e.g. ferric linoleate, cobalt naphthenate, zinc chloride or other zinc salts, or it may be formed from polythene which has previously been partially oxidized.  It is preferably applied as a solution from which the solvent is then evaporated, but may also be applied by dipping in a polythene dispersion and evaporating the liquid at a temperature above the melting point of polythene, by dipping in molten polythene, by coating with polythene powder which is then fused by flamespraying or by covering the surface with a self-supporting film of polythene which is subsequently melted. The main body of polythene may be applied by extrusion, e.g. in wire covering; by compression, injection or extrusion moulding, by calendering, by casting or by any other method in which the main body of polythene is in the softened or molten state.  The invention may be applied to electric cables, insulators, bushings and glands, e.g. for submarine cables, for the production of electrical components in which metal inserts are normally secured to a moulded insulant by mechanical means, e.g. electrical plugs and sockets, and for non-electrical uses such as the union of polythene and metal pipes, the attachment of handles to domestic articles or the replacement of rubber by polythene bushes. Metals and other materials to be bonded to polythene may first be plated with copper, to which polythene adheres strongly when applied by the method of the invention.  The invention may be used to bond sheets of polythene to metal foil.  Electrical condensers may be made by applying a thin coating of polythene to each side of metal foil, baking the foil to oxidize the polythene, assembling several layers of the foil with intervening layers of polythene film, and bonding the assembly by heat.ALSO:Polythene is united to a metal surface by forming a thin coating of polythene on the metal surface, oxidizing it by baking above its melting point, and then bending the main body of the polythene, by heat, to the thin coating of oxidized polythene. Several thin layers of polythene, oxidized to successively decreasing extents, may be used.  The thin coating of polythene may contain an oxidation catalyst, e.g. ditertiary butyl peroxide, tertiary butyl hydroperoxide, and certain metal salts, e.g. ferric linoleate, cobalt naphthenate, zinc chloride or other zinc salts, or it may be formed from polythene which has previously been partially oxidized.  It is preferably applied as a solution from which the solvent is then evaporated, but may also be applied by dipping in a polythene dispersion and evaporating the liquid at a temperature above the melting point of polythene, by dipping in molten polythene, by coating with polythene powder which is then fused by flame-spraying or by covering the surface with a self-supporting film of polythene which is subsequently melted. The main body of polythene may be applied by extrusion, e.g. in wire covering, by compression, injection or extrusion moulding, by calendering, by casting or by any other method in which the main body of polythene is in the softened or molten state.  The invention may be applied to electric cables, insulators, bushings and glands, e.g. for submarine cables, for the production of electrical components in which metal inserts are normally secured to a moulded insulant by mechanical means, e.g. electrical plugs and sockets, and for non-electrical uses such as the union of polythene and metal pipes, the attachment of handles to domestic articles or the replacement of rubber by polythene bushes. Metals and other materials to be bonded to polythene may first be plated with copper, to which polythene adheres strongly when applied by the method of the invention.