Potentially elastic conjugate fiber, production thereof, and production of fibrous structure with elasticity in expansion and contraction

Abstract

A potentially elastic composite filament, preferably a core-sheath composite filament composed of a polyurethane as the core and a polyester as the sheath, wherein the ratio of a polyurethane component having allophanate cross-linkages to a linear polyester component readily soluble in water or an aqueous alkali solution ranges from 1/1 to 90/1 and the polyester component is exposed on the surface of the filament in its cross-section. Although the core component has a high tensile strength and a large elongation at break, these properties are controlled by the sheath component. Therefore, this filament can be formed into a textile structure with good workability similar to that of ordinary synthetic fibers, and the obtained structure develops characteristics as an elastic polyurethane filament when treated with water or alkali.

Dependencies are inferred from the claim text.