Production of threads of thermoplastic cellulose derivatives

Claim 1

A PROCESS FOR THE PRODUCTION OF HIGH TENACITY THREADS OF CELLULOSE ACETATE SUITABLE FOR WEAVING CONSISTING IN HEATING DRY PREFORMED THREADS OF CELLULOSE ACETATE TO A TEMPERATURE IN THE RANGE OF 210* TO 360* CENTIGRADE TO RENDER THEM PLASTIC AND SIMULTANEOUSLY STRETCHING THEM AT LEAST 50 PER CENT WHLE THEY ARE IN THE DRY HEATED PLASTIC STATE, WHEREBY THE TENACITY OF THE THREAD IS INCREASED TO AT LEAST TWO GRAMS PER DENIER AND ITS EXTENSIBILITY CORRESPONDING REDUCED, AND SUBSEQUENTLY REHEATING THE DRY THREADS TO A TEMPERATURE WITHIN THE RANGE OF 210* TO 360* CENTIGRADE TO RENDER THEM PLASTIC AND SIMULTANEOUSLY PERMITTING THE THREADS TO SHRINK FROM ABOUT 10 PER CENT OT ABOUT 20 PER CENT WHILE THEY ARE IN THE DRY HEATED PLASTIC STATE, WHEREBY THE EXTENSIBILITY OF THE THREAD IS INCREASED TO AT LEAST 14 PER CENT, THE PLASTICITY OF THE THREAD DURING BOTH THE STRETCHING AND THE SHRINKING STEPS BEING EFFECTED SOLELY BY THE ACTION OF THE HEAT.