| 摘要 |
<p>The present invention relates to a process for the preparation of polymer yarns from ultra high molecular weight homopolymers or copolymers, wherein the process comprises the following steps: (a) preparing a suspension of a homopolymer or copolymer and a spinning or gelling solvent of a non polar nature and having a long carbon atoms chain, in the inerting vessels (1) or (2), followed by its transfer to the mixer (3), under continuous stirring and room temperature, under inerting conditions, and at a weight of homopolymer or copolymer to solvent ratio from 2/98 to 30/70, wherein said ultra high molecular weight homopolymer or copolymer is reactor bimodal or multimodal; (b) feeding said homopolymer or copolymer suspension, under inerting conditions, to the extruder (5); (c) extruding said suspension under gel forming conditions, at a temperature in excess of 150°C, and under inerting conditions; (d) spinning the gel obtained from the extrusion in a spin block (7) with a multi holed spinneret, so as to obtain non-stretched filaments with diameters of at least 1 mm, at a temperature in excess of 150°C, maintaining the inerting conditions; (e) cooling the non-stretched filament bundles, coming from the spin block (7), by immersion in a tank (8) with a circulation system (9), wherein the renovation of cold water enters said bath at a spot directly opposite and aligned with the center of the filament bundle, guaranteeing a perfect homogeneity of the cooling system; (f) treating said non stretched yarn with a second extraction solvent for the removal of the first spinning solvent, and later recovering these solvents in a solvent separation process; (g) drying said non stretched yarn for the removal of the second solvent; and (h) stretching said dry yarn by means of a stretching system (18 to 21), in a continuous manner, comprising at least one stretching step.</p> |
