Patent ID: 7056581
Filing Date: 2006-06-06
Classification: D01F,Y10T

Abstract:
1. A fiber comprising: a core, and a sheath having a volume, wherein the sheath at least partially surrounds the core; an additive disposed in the sheath and optionally in the core, the additive determining a desired physico-chemical parameter; wherein the fiber is spun such that without increasing an amount of the additive in the fiber the desired physico-chemical parameter increases when the volume of the sheath decreases; wherein the core and the sheath comprise a polymer having an intrinsic viscosity IV of at least 0.75; wherein the additive comprises an ultraviolet-light (UV) absorbing agent and the desired physico-chemical parameter comprises retention of tenacity after UV irradiation; and wherein the UV absorbing agent is present in an amount of about 0.5 wt %, wherein the core and the sheath have a volume ratio of 90:10, and wherein the retention of tenacity after UV irradiation is no less than 41%.