| 摘要 |
1,025,098. Producing drawn nylon filaments. E. I. DU PONT DE NEMOURS & CO. May 22, 1963 [May 22, 1962; April 23, 1963], No. 20482/63. Heading B5B. Drawn nylon filaments comprising a copolymer of polyhexamethylene adipamide and polycaproamide or a terpolymer of polyhexamethy lene adipamide, polyhexamethylene sebacamide and polycaproamide, in which the percentage concentrations of the polyamides fall within the area ABCDE of the accompanying drawings, and having a " shrinkage tension to shrinkage ratio " below 0À70 and a boil-off shrinkage of 8-15% may be produced by melt spinning the polymer, cold drawing the filaments produced, and relaxing the cold drawn yarns. The shrinkage tension is determined by placing a sample of the yarn which has been permitted to relax for 24 hours at 74‹ F. and 72‹ R.H. between the jaws spaced 10 inches apart of an Instron Tester, immersing the yarn sample of water at 90‹ C. for 5 minutes, withdrawing the now tensioned sample, permitting it to cool and dry at room temperature for 5 minutes, reading the tension in grams and recording it in grains per denier. Filament shrinkage is determined by measuring a length of the filament when held under sufficient tension to keep it straight without tension, treating the measured length in a relaxed state with boiling water for 15 minutes, drying and measuring the boiled-off length and expressing the shrinkage as a percentage. The shrinkage-tension/shrinkage factor is calculated by dividing the shrinkage tension, measured in grams per denier, by the per cent shrinkage in boiling water and multiplying the resultant quotient by 100. The filaments may have an initial modulus no greater than 12 grams/denier and a tenacity of at least 4 grams/denier. The filaments may have a nuclear magnetic resonance factor greater than 1.0, preferably at least 1À2. They may contain a small proportion of a salt of terephthalic acid, for example 0.25 to 3% of calcium teraphthalate. In their production they may be relaxed by 2-3% after allowing them to stand for at least 30 minutes, or by 12-15% continuously with the cold drawing. In an example, the melt extruded filaments are cold drawn over a pin at a draw ratio of 4À74 and after standing for 24 hours are relaxed and annealed by several passes over a steam-heated hot plate whose temperature is 150‹ to 200‹ C. with two rollers permitting 2À5% shrinkage.
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