HOLLOW NYLON FILAMENTS AND YARNS AND PROCESS FOR MAKING SAME

摘要

A melt spinning process and the nylon hollow filaments and yarns made by such process which includes extruding molten nylon polymer having a relative viscosity (RV) of at least about 50 and a melting point (TM) of about 210 DEG C. to about 310 DEG C. from a spinneret capillary orifice with multiple orifice segments providing a total extrusion area (EA) and an extrusion void area (EVA) such that the fractional extrusion void content, defined by the ratio [EVA/EA] is about 0.6 to about 0.95, and the extent of melt attenuation, defined by the ratio [EVA/(dpf)S], is about 0.05 to about 1.5, in which (dpf)S is the spun denier per filament, the (dpf)S being selected such that the denier per filament at 25% elongation (dpf)25 is about 0.5 to about 20 denier; withdrawing the multiple melt streams from the spinneret into a quench zone under conditions which causes substantially continous self-coalescence of the multiple melt streams into spun filaments having at least one longitudinal void and a residual draw ratio (RDR) of less than 2.75; and stabilizing the spun hollow filaments to provide hollow filaments with a residual draw ratio (RDR) of about 1.2 to about 2.25.