Drawing extruded mesh to orientated strands around hexagonal holes - to produce fully oriented branching in less than three stages

摘要

Thermoplastic mesh structures produced by extrusion and subsequent stretching of tubular or slit tubular mesh to produce hexagonal interstices bounded by oriented strands where the orientation is aligned with the oblique strand intersections and not around acute strand intersections. The orientation is produced from mesh initially extruded with four-sided interstices having globular intersections between strands which intersect at angles of 90-110 degrees. Orienting is effected by (a) longitudinal stretching to original strands, followed by lateral stretching without longitudinal stress, to draw lateral strands from the intersections; (b) radial stretching without longitudinal stress to simultaenously orient the original strands and draw out the intersections; or (c) slitting and lateral stretching of the sheet mesh without longitudinal stress to simulatenously orient the original strands and draw out the intersections. Used esp. for making netting from materials with a relatively low tendency to split or fibrillate, e.g. low or medium density polyethylene or polyamides.