Abstract Crimped regenerated cellulose fibre is made from viscose by submitting freshly spun filaments emerging from a conventional spinning bath to a stretch equal approximately to one third of the total stretch to be imparted, while the filaments still substantially consist of cellulose xanthate and while they are still in the plastic state, conducting the partly stretched filaments through an acid bath for their further though not yet complete transformation into cellulose hydrate, subjecting them either in, or outside, this bath to a second stretching which corresponds to the difference between the initial stretch and the total stretch, and then, after substantially completely transforming the filaments into staple lengths, immersing the staple lenths in a hot water or alkaline bath, and finally submitting them to conventional after-treatment. Preferably the partially stretched filaments are 70-95% converted to cellulose hydrate prior to the second stretch, which may be carried out in an aqueous sulphuric acid bath. Preferably, also, the viscose has a ratio of alkali to a -cellulose of below 0.9, e.g. 0.8-0.85. The total stretch of the fibre may correspond to 60-65% of its original length. An example is given. Specification 499,671 is referred to.
IN A METHOD OF PRODUCING CRIMPED REGENERATED CELLULOSE FIBERS FROM VISCOSE BY SUBJECTING FRESHLY SPUN VISCOSE FIBERS TO A PREDETERMINED STRETCH CORRESPONDING TO A REDUCTION IN THE DIAMETER OF THE FIBER TO BETWEEN 6065% OF THE ORIGINAL DIAMETER, THE STEPS OF SUBJECTING A VISCOSE FIBER EMERGING FROM A SULFURIC ACID PRECIPITATING BATH CONTAINING MORE THAN 100 G./1. OF SULFURIC ACID AND MORE THAN 300 G./.1 OF SODIUM SULFATE AND BEING STILL IN PLASTIC STATE AND CONSISTING MAINLY OF CELLULOSE XANTHOGENATE TO A FIRST STRETCH CORRESPONDING TO ABOUT ONETHIRD OF THE TOTAL OF SAID PREDETERMINED STRETCH; CONVERTING ABOUT 75-95% OF THE ORIGINAL CELLULOSE XANTHOGENATE TO CELLULOSE HYDRATE IN AN ACID BATH SO AS TO FORM A PARTIALLY STRETCHED, PARTIALLY CONVERTED FIBER; SUBJECTING THE THUS PARTIALLY STRETCHED, PARTIALLY CONVERTED FIBER AFTER SAID CONVERSION OF ABOUT 75-95% OF THE ORIGINAL CELLULOSE XANTHOGENATE TO CELLULOSE HYDRATE TO A SECOND STRETCH CORRESPONDING TO THE DIFFERENCE BETWEEN SAID FIRST STRETCH AND THE TOTAL OF SAID PREDETERMINED STRETCH; COMPLETING CONVERSION OF THE THUS FURTHER STRETCHED FIBER TO REGENERATED CELLOSE; CUTTING THE THUS OBTAINED FIBER OF REGENERATED CELLULOSE INTO FIBER SEGMENTS; AND TREATING THE THUS OBTAINED FIBER SEGMENTS IN A HOT BATH SO AS TO OBTAIN HIGHLY CRIMPED FIBER SEGMENTS OF REGENERATED CELLULOSE.
Claim 2
Dependent Claim
205 words
IN A METHOD OF PRODUCING CRIMPED REGENERATED CELLULOSE FIBERS FROM VISCOSE BY SUBJECTING FRESHLY SPUN VISCOSE FIBERS TO A PREDETERMINED STRETCH CORRESPONDING TO A REDUCTION IN THE DIAMETER OF THE FIBER TO BETWEEN 6065% OF THE ORIGINAL DIAMETER, THE STEPS OF SUBJECTING A VISCOSE FIBER EMERGING FROM A SULFURIC ACID PRECIPITATING BATH CONTAINING MORE THAN 100 G./1. OF SULFURIC ACID AND MORE THAN 300 G./.1 OF SODIUM SULFATE AND BEING STILL IN PLASTIC STATE AND CONSISTING MAINLY OF CELLULOSE XANTHOGENATE TO A FIRST STRETCH CORRESPONDING TO ABOUT ONETHIRD OF THE TOTAL OF SAID PREDETERMINED STRETCH; CONVERTING ABOUT 75-95% OF THE ORIGINAL CELLULOSE XANTHOGENATE TO CELLULOSE HYDRATE IN AN ACID BATH SO AS TO FORM A PARTIALLY STRETCHED, PARTIALLY CONVERTED FIBER; SUBJECTING THE THUS PARTIALLY STRETCHED, PARTIALLY CONVERTED FIBER AFTER SAID CONVERSION OF ABOUT 75-95% OF THE ORIGINAL CELLULOSE XANTHOGENATE TO CELLULOSE HYDRATE TO A SECOND STRETCH CORRESPONDING TO THE DIFFERENCE BETWEEN SAID FIRST STRETCH AND THE TOTAL OF SAID PREDETERMINED STRETCH; COMPLETING CONVERSION OF THE THUS FURTHER STRETCHED FIBER TO REGENERATED CELLOSE; CUTTING THE THUS OBTAINED FIBER OF REGENERATED CELLULOSE INTO FIBER SEGMENTS; AND TREATING THE THUS OBTAINED FIBER SEGMENTS IN A HOT BATH SO AS TO OBTAIN HIGHLY CRIMPED FIBER SEGMENTS OF REGENERATED CELLULOSE.