Partially-stretched film prodn - using strands in centre layer of higher m pt than outer layers

摘要

The multi-head extruder develops outer layers such as of polyethylene with drillings to give a centre layer of strands of e.g. polyamide, so that on passing through the cooling channel the friction effect by the still-molten outer layers between the cooling channel wall and the solid strands gives them a partial stretching effect. An armoured and reinforced character is introduced into partially stretched film material.