| 摘要 |
<p>Process for the production of walls or sheets of lacunate structure forming meshes or nets of synthetic, especially thermoplastic material, of the type in which a plastic film is continuously extruded by a circular or rectilinear extrusion head provided with notched cutters, teeth or combs, in which process: a) the thickness of the extruded film is stabilised by laminar flow of the thermoplastic, upstream of the extrusion head, by transition in a corridor of cross-section equal to the cross-section of the extrusion slot, thereby preventing the formation of surface irregularities or bends (regions of increased thickness); b) the lacunate film thus extruded, of constant thickness and brought to a suitable temperature close to the softening point, is subjected to a drawing (stretching) operation, especially in the longitudinal direction, in order to cause an elongation of the drawn (stretched) elements, thereby causing a molecular reorientation of the thermoplastic resin. <IMAGE></p> |
