Viscose spinning process

Claim 1

A PROCESS FOR THE PRODUCTION OF HIGH TENACITY, CRIMPED REGENERATED CELLULOSE FILAMENTS WHICH COMPRISES THE STEPS OF SPINNING FILAMENTS BY EXTRUDING INTO A SULFURIC ACID-SODIUM SULFATE-ZINC SULFATE COAGULATING AND REGENERATING BATH A VISCOSE WHICH IS HIGHLY XANTHATED WITH AT LEAST 35% OF CARBON DISULFIDE BASED ON THE CELLULOSE CONTENT, IS SUBSTANTIALLY UNRIPENED AT A SALT INDEX OF AT LEAST 7, AND CONTAINS DISSOLVED THEREIN ABOUT 0.1 TO 10 MILLIMOLES PER 100 GRAMS OF VISCOSE OF A COAGULATION MODIFIER WHICH LOWER THE GEL SWELLING FACTOR BY AT LEAST 8% AND DECREASES THE RATE OR NEUTRALIZATION OF THE FILAMENT BY AT LEAST 50% AS COMPARED WITH CORRESPONDING VALUES FOR A SIMILAR BUT UNMODIFIED VISCOSE SPINNING SYSTEM, THEN STRETCHING THE COAGULATED FILAMENTS IN A NONALKALINE AQUEOUS SECONDARY BATH, AND FINALLY RELAXING THE SUBSTANTIALLY COMPLETELY REGENERATED FILAMENTS IN THE COMPLATE ABSENCE OF TENSION IN AN QUEOUS SWELLING BATH, SAID STEPS BEING CARRIED OUT WITH OBSERVANCE OF THE FOLLOWING CRITICAL CONDITIONS: (A) THE VISCOSE HAS A CELLULOSE CONTENT BETWEEN 5% AND 7%, (B) THE VISCOSE HAS AN ALKALI CONTENT (CALCULATED AS NAOH) BETWEEN 5% AND 7%, (C) THE COAGULATING AND REGENERATING BATH HAS A SULFURIC ACID CONTENT BETWEEN 6% AND 10% BUT NOT ABOVE THE ACIDITY WHICH PRODUCES THE MINIMUM GEL SWELLING FACTOR, (D) THE COAGULATING AND REGENERATING BATH HAS A SODIUM SULFATE CONTENT BETWEEN 14% AND 21%, (E) THE COAGULATING AND REGENERATING BATH HAS A ZINC SULFATE CONTENT BETWEEN 6% AND 15%, (F) THE TEMPERAURE OF THE COAGULATING AND REGENERATING BATH IS BETWEEN 40 AND 65*C., (G) THE FILAMENT TRAVELS BETWEEN 15 AND 150 INCHES IN THE COAGULATING AND REGENERATING BATH, (H) THE STRETCH, AS MEASURED IN THE SECONDARY BATH, IS BETWEEN 70% AND 160%, (I) THE FINAL TENSION ON THE FILAMENT IS BETWEEN 0.5 AND 1.0 GRAMS PER DENIER, (J) THE TEMPERATURE OF THE SECONDARY STRETCHING BATH IS BETWEEN 50 AND 100*C., WITH NOT MORE THAN THREE OF SAID CRITICAL CONDITIONS BEING OUTSIDE OF THE FOLLOWING OPTIMIUM RANGES: (A) CELLULOSE CONTENT OF VISCOSE--PERCENT-- 5 TO 6 (B) ALKALI CONTENT OF FISCOSE-------DO---- 5.5 TO 6 (C) SULFURIC ACID IN THE BATH-------DO---- 6 TO 8.5 (D) SODIUM SULFATE IN THE BATH------DO---- 14 TO 18 (E) ZINC SULFATE IN THE BATH---------DO---- 9.5 TO 13 (F) TEMPERATURE OF COAGULATING BATH--*C-- 50 TO 60 (G) LENGTH OF TRAVEL IN COAGULATING BATH INCHES-- 15 TO 35 (H) STRETCH IN SECONDARY BATH----PERCENT-- 100 TO 140 (I) FINAL TENSION----------------G.P.D-- 0.7 TO 0.9 (J) TEMPERATURE OF SECONDARY BATH---*C-- 80 TO 100