PROCESS TO MANUFACTURE A MULTIPLE LAYER LAMINATED MATERIAL, PROCESS TO PROCESS POLYMERS, PROCESS TO PRODUCE A SERIES OF COEXTRUDED FILM STRUCTURES, LAMINATED MATERIAL, PACKAGING, APPLIANCES TO MANUFACTURE FIRST AND SECONDARY MACHINING

摘要

Method and apparatus for fabricating multiple layer sheet materials are adapted to minimize the time of exposure of a sensitive polymeric melt stream to contact with metal. The method comprises encapsulating the sensitive melt stream (12) with a second polymeric melt stream (16) which preferably is of a lower viscosity, at the outlet of the apparatus or extruder (10) which produces the sensitive melt stream (12). When the encapsulating melt stream (16) has a lower viscosity than the sensitive melt stream, a transport means (36) - an elongated pipe - is preferably employed between the encapsulating means (20) and an extrusion die (42), whereby thickness variations about the circumference of the encapsulating melt stream (16) are reduced. The method and apparatus are especially beneficial for the extrusion of vinylidene chloride copolymers in the manufacture of multi-layer packaging films containing one or more layers of VDC copolymers. IMAGE IMAGE