Process for improving the pill resistance of two-component acrylonitrile polymers

Claim 1

IN A PROCESS FOR PREPARING STAPLE FIBER FROM COMPOSITE FILAMENTS, THE RESULTING STAPLE FIBER HAVING IMPROVED RESISTANCE TO PILLING WHICH COMPRISES SIMULTANEOUSLY WASHING AND DRAWING A TOW OF CONTINUOUS FILAMENTS WHEREIN SAID FILAMENTS HAVE TWO ECCENTRICALLY POSITIONED SECTIONS OF DIFFERENT ACRYLONITRILE POLYMERS EXTENDING ALONG THEIR LENGTHS, THE IMPROVEMENT WHICH COMPRISES A CONTROLLED RELAXATION STEP PROVIDED BY CONTINUOUSLY PASSING SAID FILAMENTS UNDER A SLIGHT TENSION THROUGH A HEATED PLASTICIZING MEDIUM, THE TENSION ON SAID FILAMENTS AND THE TEMPERATURE OF SAID MEDIUM BEING CONTROLLED TO UNIFORMLY SHRINK SAID FILAMENTS AN AMOUNT EQUAL TO AT LEAST 50% OF THE BOIL-OFF SHRINKAGE OF SAID DRAWN FILAMENTS, AND CONVERTING THE RESULTING TOW OF RELAXED CONTINUOUS FILAMENTS TO STAPLE FIBER AND DRYING THE STAPLE FIBER AT HIGH TEMPERATURE.