GB1356803A - Preparation of plastic-metal products including laminates composite tubes and the like - Google Patents

Abstract

1356803 Metal-plastics laminates R W ERWIN 24 May 1971 [28 May 1970] 16633/71 Heading B5N [Also in Division F2] Fluorinated or perfluorinated hydrocarbon polymer plastics film is adhered to a metal surface without use of adhesive by applying heat to soften the plastics and bond it to the metal, heating and bonding taking place under reduced pressure, to prevent entrapment of air, and without application of pressure to the external surface of the film. The plastics is preferably a tetrafluoroethylene polymer (e.g. hexafluoropropylene-tetrafluoroethylene copolymer) and may be applied to each face or to one face only of a metal sheet; the exposed faces of the plastics may have been chemically treated for adhesion to other materials. The metal may be Al, Fe, Cu or an alloy thereof (e.g. Cu-Ni, brass containing Al) and may be oxidizable or non-oxidizable at the bonding temperature, e.g. 450-625‹ F.; its surface may be flat or curved. Laminates prepared by this method are used to make tubes for use as pipe-liners (see Divisions B8, F2). An exposed metal surface may have an edge strip of the plastics bonded thereto to facilitate tube manufacture. As shown in Fig. 9, a metal sheet 13 and a plastics sheet 14 are disposed upon a longitudinally-extending stiff metal coil 11, which is supported in a slot 16 in a pipe 7 and whose turns are spaced apart by end strips 12 to allow room for the initial expansion of the plastics sheet which takes place on heating. The assembly is held by straps 10 and is supported inside a cylinder which can be closed, evacuated and subjected to heat. As shown in Fig. 11, the laminating operation is carried out in a closed metal apparatus comprising containers 18, 19, 20 and curved conduits 22, 25, which can be evacuated at 21 to produce'a substantially complete vacuum. Two plastics films 28a, 29a are bonded to one face of a metal sheet 30a (which has previously been cleaned by solvent) by applying heat at 23. The assembly is (optionally) partially cooled in zone 24 and the plastics-coated face is coated with a release agent, e.g. silicone, by a roller 34 to prevent sticking to the conduit 25. Two plastics films 37a, 38a are then similarly applied to the exposed metal face of the assembly.