METHOD AND APPARATUS FOR FORMATION OF THERMOPLASTIC FILM

摘要

An apparatus and method for high-production rate processing of extruded tubular thermoplastic thick-thin film having at least one, preferably two, thickened wall profiles in the longitudinal direction of the film as it is formed. The method steps includes extruding a molten thermoplastic extrudate from an annular die, cooling the extrudate so as to form a film bubble having a thickened wall portion, and further cooling the thickened wall portion to avoid difficulties after the bubble is collapsed and fed through nip rolls for collection or subsequent processing. The product film is especially useful for shopping bags with handles.