Heat shrinkable laminated film and method for its production

1522397 Laminates W R GRACE & CO 30 Sept 1976 [2 Oct 1975] 40681/76 Heading B5N and B5B A method of making a heat-shrinkable packaging film comprises : (a) forming a laminate, e.g. by co-extrusion, comprising an oxygen barrier layer comprising a hydrolysed ethylenevinyl acetate copolymer disposed between two other polymeric layers, at least one of which comprises a cross-linked polymer, (b) heating the laminate to the orientation temperature of the cross-linked polymer and (c) stretching the heated laminate to orient the cross-linked polymer. The cross-linked polymer may be a homo- or copolymer of an olefine, an exemplified comonomer being vinylacetate, cross-linking being effected by irradiation or chemically. Other polymers which may be present in the laminate are polyvinyl chloride, polyamides, comonomers, acrylic polymers, polyesters, polycarbonates, polystyrene and polyvinylidene chloride.