Low shrinkage, high tenacity poly(hexamethylene-adipamide) yarn and process for making same.

摘要

A polyamide yarn is disclosed which is at least 85% by weight poly(hexamethylene adipamide) and which has a relative viscosity of greater than 50, a tenacity of at least about 9.5 g/d, a modulus of at least about 30 g/d, a shrinkage at 160 DEG C of less than about 2 percent, a crystal perfection index of greater than about 83, and a long period spacing of greater than about 105 ANGSTROM . The process for making the yarn includes drawing of a feed yarn while heating to at least about 190 DEG C in at least a final draw stage to a draw tension of at least 3.8 g/d, subsequently decreasing the tension while heating to at least about 190 DEG C to produce a length decrease of between about 13.5 and about 30%, and cooling and packaging the yarn.