Studies of the Drawing of Polyamide Fibers. I. Dependence of Some Physical Properties on the Draw Ratio

Abstract

Abstract The relation between the draw ratio and some physical properties of nylon 6 fibers was investigated, using monofilament drawn in hot water to various draw ratios. The tensile strength decreases, passes through a minimum at a draw ratio near 2, and then increases as the draw ratio becomes higher. The decrease in strength at the minimum in the sample drawn immediately after spinning amounts to 60% of the strength of the undrawn sample. The shrinkage in boiling water of the sample drawn immediately after spinning is nearly zero in the range of a low draw ratio, increases in the range of the ratio from ca. 2 to ca. 3.5, and gradually approaches a saturating value, but that of the samples drawn many days after spinning increases most rapidly in the range of the ratio from 1 to ca. 2 and then gradually approaches to a saturating value with the draw ratio. On the first stage of drawing, the rate of increase in birefringence with the draw ratio of the sample drawn immediately after spinning is smaller than that of the sample drawn many days after spinning. On the basis of these results, the authors discussed the mechanism of the drawing of polyamide filaments.