Self-crimping multi-component polyester filament wherein the components contain differing amounts of polyolefin

Claim 1

A process for producing a self-crimping, multi-component filament, comprising, co-extruding at a given speed (extrusion speed) at least two molten fiber-forming components in a side-by-side or asymmetric sheathcore configuration to form a molten multicomponent filament, wherein one of the components comprises a polyester containing a minor amount of polyolefin dispersed therein and the other component(s) comprises (comprise) a polyester of the same chemical structure containing a lesser amount of polyolefin, cooling the molten filament in a quenching zone to form a solid filament, attenuating and accelerating the filament from its point of formation by withdrawing the solidified filament from the quenching zone at a speed (spinning speed) which is greater than the extrusion speed, wherein the extrusion speed, amount of polyolefin in the components, the spinning speed and denier of the filament are correlated to provide an as-spun filament having a total bulk of at least 10% and wherein said polyolefin consists essentially of recurring units of the formula --CH 2 CRR'-- where R and R' are atoms or radicals which do not render said polyester incapable of forming fibers.