PROCESS FOR PRODUCING AN EXTRUDED AND STRETCHED TUBULAR MATERIAL AND STRETCHED TUBULAR MATERIAL

摘要

Extruded and stretched tubular material may be produced by an improvement on the blown bubble process for forming thin heat sealable films. In this improvement a spray nozzle, internal to the extruded tubular structure, is used to provide a thin inner coating of a liquid polyorganosiloxane which greatly reduces the internal film welding of extruded tubular polyolefin materials which internally weld at their processing temperature. Additionally, reduction of the internal welding allows films of reduced thickness to be manufactured.