Dyeable bulky yarns based on polypropylene

Claim 1

A PROCESS FOR PRODUCING A DYEABLE BULKY CONTINUOUS FILAMENT YARN WHICH CONSISTS ESSENTIALLY OF STRETCHING A YARN FORMED FROM SMOOTH CONTINUOUS FILAMENTS OF A MIXTURE CONSISTING ESSENTIALLY OF CRYSTALLINE POLYPROPYLENE AND FROM ABOUT 1 TO 20%, BASED ON THE TOTAL WEIGHT OF THE MIXTURE, OF ANOTHER RESIN SELECTED FROM THE GROUP CONSISTING OF: POLYOLEFINS, EPOXY RESINS, POLYAMIDES, POLYALKYLENIMINES, POLYESTERS, POLYAMINOTRIAZOLES, POLYCAPROLACTAM AND MIXTURES THEREOF; AT A TEMPERATURE BETWEEN 20* C. AND 110* C. AND AT THE HIGHEST RATE OF STRETCHING WHICH THE FILAMENTS WILL WITHSTAND WITHOUT BREAKING, BY FEEDING THE YARN THROUGH A STRETCHING ZONE AT THE RATE OF 10 TO 150 METERS PER MINUTE TO INTRODUCE IRREGULARLY DISTRIBUTED INTERNAL STRAINS INTO THE FILAMENTS, AND THEN RAPIDLY HEATING THE STRETCHED YARN AT A TEMPERATURE BETWEEN ABOUT 50* C. AND 150* C., WITHOUT APPLYING TENSION TO THE YARN, TO RELAX THE IRREGULARLY DISTRIBUTED INTERNAL STRAINS INTRODUCED BY THE STRETCHING AND OBTAIN A YARN THE SYNTHETIC POLYMER FILAMENTS OF WHICH ARE CRIMPED IRREGULARLY ALONG THEIR LENGTH, WITH THE LOOPS DISPOSED IN DIFFERENT PLANES.