Process for producing highly crimped fibers having modified surfaces

Claim 1

IN THE PROCESS OF PRODUCING CRIMPED FILAMENTS BY EXTRUDING MOLTEN SYNTHETIC LINEAR ORGANIC POLYMER IN THE FORM OF FILAMENTS FOLLOWED BY ASYMMETRIC QUENCHING TO PRODUCE UNORIENTED FILAMENTS HAVING AN ASYMMETRIC BIREFRINGENCE DIFFERENTIAL ACROSS THE DIAMETER OF THE FILAMENTS, AND THEN DRAWING THE FILAMENTS TO PROVIDE A SUBSTANTIALLY ORIENTED STRUCTURE, THE IMPROVEMENT FOR PRODUCING FILAMENTS CHARACTERIZED BY A HIGH CRIMP AND A LOW COEFFICIENT OF HYDRODYNAMIC FRICTION WHICH COMPRISES CONTACTING THE UNORIENTED, ASYMMETRICALLY BIREFRINGENT FILAMENTS UNDER TENSION WITH A CRACKING AGENT, THEN APPLYING TO THE FILAMENTS A LIQUID MEDIUM FREE OF CRACKING AGENT AND DRAWING THE WET FILAMENTS AT A TEMPERATURE BELOW 83*C. TO PROVIDE A SUBSTANTIALLY ORIENTED STRUCTURE HAVING THE PROPERTY OF SPONTANEOUSLY DEVELOPING FROM 15 TO 50 CRIMPS PER INCH OF FILAMENT UNDER ESSENTIALLY TENSIONLESS CONDITIONS.