Abstract: Disclosed herein are poly(phenylene sulfide) fibers having a tensile strength of at least 3.5 g/d, a knot tenacity of at least 2 g/d, a loop tenacity of at least 3.5 g/d, the number of abrasion cycles until breaking in a flexing abrasion test of at least 3,000 times, and the number of repeated flexings until breaking in a flexural fatigue test of at least 150 times. A process for the production of poly(phenylene sulfide) fibers, which comprises melt-spinning a poly(phenylene sulfide), stretching the resultant unstretched filaments at a draw ratio of 2:1 to 7:1 within a temperature range of 80.degree.-260.degree. C., and heat-treating the stretched filaments for 0.1-30 seconds under conditions of a take-up ratio of 0.8:1 to 1.35:1 in a dry heat atmosphere exceeding 285.degree. C., but not exceeding 385.degree. C. is also disclosed.

Abstract: Disclosed herein are poly(phenylene sulfide) fibers having a tensile strength of at least 3.5 g/d, a knot tenacity of at least 2 g/d, a loop tenacity of at least 3.5 g/d, the number of abrasion cycles until breaking in a flexing abrasion test of at least 3,000 times, and the number of repeated flexings until breaking in a flexural fatigue test of at least 150 times. A process for the production of poly(phenylene sulfide) fibers, which comprises melt-spinning a poly(phenylene sulfide), stretching the resultant unstretched filaments at a draw ratio of 2:1 to 7:1 within a temperature range of 80.degree.-260.degree. C., and heat-treating the stretched filaments for 0.1-30 seconds under conditions of a take-up ratio of 0.8:1 to 1.35:1 in a dry heat atmosphere exceeding 285.degree. C., but not exceeding 385.degree. C., is also disclosed.