| 摘要 |
<p>1535772 Stretched extruded nets NETLON Ltd 26 May 1976 [12 June 1975] 25267/75 Heading D1R A mesh, Fig. 5, having 6-sided openings is formed by stretching 4 sided plastics mesh, Fig. 2, to produce molecular orientation in strands 5a, 5b, 6a, 6b and deform the intersections 7 into strands 7a comprising confluent portions of pairs of the original strands, at least a portion of each strand 7a being molecularily orientated whilst portions 7b at each end of the strands 7a remain unorientated. The starting mesh may be formed by extrusion with the intersections formed before or as the strands are extruded, or by adhesive bonding of the strands where they cross. Preferably the mesh is tubular and formed from a counter-rotating concentric pair of circular dies 1, 2, Fig. 1, having spaced orifices 3, 4 of generally trapezoidal cross-section with relieved trailing edges 3a, 4a. This avoids a sharp cut-off of the extruded plastics material as the orifices separate and thereby facilitates necking of the intersections 7 when the mesh is subject to transverse drawing. The mesh angleαis 90-110‹. The mesh is given a first stretch in the transverse or preferably the machine direction to orientate strands 5, 6. It is then stretched in the machine or preferably the transverse direction, e.g. by passage over a flexible carrier sleeve embracing a diverging hollow internal mandrel, to deform the intersections into strands. The stretching yields a lighter net with a softer feel. Specification 39546/74 claims a similar net in which however the stretching has been sufficient to molecularly orientate all the material of strands 7.</p> |
