POTENTIALLY ELASTIC CONJUGATE FIBER, PRODUCTION THEREOF, AND PRODUCTION OF FIBROUS STRUCTURE WITH ELASTICITY IN EXPANSION AND CONTRACTION.

摘要

A potentially elastic conjugate fiber, preferably a core-sheath conjugate fiber 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 fiber 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 fiber can be formed into a fibrous 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.