| 摘要 |
1,245,361. Polyester yarns. SOC. RHODIACETA. 18 Feb., 1969 [19 Feb., 1968], No. 8859/69. Heading B5B. [Also in Divisions D1-D2] Textile articles e.g. woven or knitted fabrics, comprise continuous multifilament yarns, or staple fibres obtained from such yarns, of polyester material, each filament comprising alternating zones in which its diameter increases and decreases progressively between at least two different mean values, the zones of lowest diameter corresponding to the zones having the highest crystallinity index and a higher molecular orientation, each filament also having a non- spiral three-dimensional crimp and being of bulky appearance. The filaments are preferably made of polyethylene terephthalate, the alternating zones having crystallinity indices differing by between 10 and 30%, the thick zones being practically wholly unoriented and amorphous. A process for making the textile articles above comprises, as the sole stretching operation, partially stretching an unstretched polyester multifilament yarn to a stretch ratio of at least 2 in contact with a crack-promoting agent e.g. a hydroxylated compound in an aqueous solution or an aqueous lower alcohol, and heattreating the partially stretched yarn in the relaxed state. The yarn is preferably heated during stretching. Apparatus for carrying out the process comprises in sequence a yarn feeding means 5, 6, means 7 for applying a crackpromoting agent, means 8, 9 for continuously stretching the yarn in contact with the crackpromoting agent, a heat relaxation element consisting of a yarn heating means 12 combined with means 13, 14 for relaxing the yarn and yarn winding up means 10. The heating means 12 may comprise a saturated steam chamber or a heated air nozzle. The filaments of the yarn may be interlaced by means located between the stretching rollers 8, 9 and the heat relaxation element. |
