| 20090123748 | Process for the production of high tensile strength and low creep polymer yarns, high tensile strength and low creep polymer or copolymer yarns, and, the use of such yarns - The present invention relates to a process for the production of high tensile strength and low creep polymer yarns, wherein it comprises the following steps: (a) preparing a mixture of: (i) a first ultra high molecular weight polyolefin polymer or copolymer, (ii) a second clay nanocomposite polyolefin polymer or copolymer, and (iii) a non-polar spinning solvent, (b) feeding the resulting suspension through an extruder at a temperature of at least 180° C., causing the formation of a gel, (c) spinning the gel so obtained in a spinneret with a length to diameter ratio (L/D) of at least 15, (d) cooling the yarn to a temperature below 2° C., (e) subsequently removing the non-polar spinning solvent, and (f) drawing the yarn so obtained so as to obtain a tensile strength value of at least 18 cN/Dtex and a creep value lower than 0.07% per hour, wherein the first ultra high molecular weight polyolefin polymer or copolymer has a weight-average molecular weight higher than 2,000,000 g/mol and a polydispersivity of at least 7, and the second clay nanocomposite polyolefin polymer or copolymer is obtained via in situ polymerization of an olefin and an exfoliated layered clay, the polyolefin so obtained having a weight-average molecular weight of at least 400,000 g/mol. | 05-14-2009 |
