| 摘要 |
A polyester fiber which comprises at least 90 wt.% polytrimethylene terephthalate and has a peak thermal stress of 0.1 to 0.35 g/d, a boiling-water shrinkage of 5 to 16 %, a strength of 3 g/d or higher, and an elongation of 20 to 60 %, and in which the relationship between modulus Q (g/d) and elastic recovery R (%) satisfies expression (1): 0.18</=Q/R</=0.45 and the loss tangent has a peak at 90 to 120 DEG C. The polyester fiber is a polytrimethylene terephthalate fiber whose elongation, thermal stress, and boiling-water shrinkage are in respective adequate ranges, and gives a woven or knit fabric which is prevented from suffering excess thermal shrinkage during processing and has a low modulus and soft texture. Hence, the polyester fiber is suitable for use in applications such as innerwear, outerwear, sportswear, legwear, back fabrics, and swimming suits. This polyester fiber can be industrially produced stably at high efficiency by a process in which spinning and stretching are successively conducted and the unstretched fiber does not change with time. |
