Method of producing viscose rayon staple and a spinning apparatus for use in the method

Claim 1

METHOD OF PRODUCING A VISCOSE FIBERS COMPRISING EXTRUDING A VISCOSE HAVING A GAMMA VALUE OF AT LEAST 60 AND CONTAINING BETWEEN 4% AND 7% BY WEIGHT OF A CELLULOSE COMPONENT HAVING A DEGREE OF POLYMERIZATION OF AT LEAST 500 AND BETWEEN 3% AND 6% BY WEIGHT OF SODIUM HYDROXIDE THROUGH AN ANNULAR SPINNERET PROVIDED WITH A CHANNEL AT ABOUT ITS CENTER, WITH AT LEAST 10,000 ORIFICES AROUND THE CHANNEL AT A TEMPERATURE NOT HIGHER THAN 30* C. INTO A COAGULATION BATH CONTAINING NOT MORE THAN 30 G./L. OF SULPHURIC ACID, AT LEAST 0.1 G./L. OF ANHYDROUS ZINC SULPHATE AND NOT MORE THAN 80 G./L. OF ANHYDROUS SODIUM SULPHATE, THE COAGULATION LIQUID BEING ALLOWED TO FLOW INTO THE BATH IN SUBSTANTIALLY THE SAME DIRECTION AS THAT OF THE EXTRUSION OF THE VISCOSE, STRETCHING THE PARTIALLY REGENERATED FILAMENTS WITH A DRAW RATIO OF 1.5 TO 3.5 BY MEANS OF A PAIR OF ROLLERS OUTSIDE THE BATH, AND COMPLETING THE REGENERATION IN A HOT AQUEOUS BATH CHARACTERISED IN THAT THE VISCOSE IS EXTRUDED INTO THE COAGULATION BATH AT A SPINNING LINEAL SPEED NOT EXCEEDING 10 M./MIN., 1/4 TO 3/4 OF THE TOTAL AMOUNT OF THE FLOW OF THE COAGULATION LIQUID INTO THE BATH IS PASSED THROUGH SAID CHANNEL IN THE SPINNERET, WHEREIN THE DIFFERENCE IN THE SULPHURIC ACID CONTENT OF THE COAGULATION LIQUID CONTINUOUSLY SUPPLIED TO THE BATH AND THAT CONTINUOUSLY WITHDRAWN FROM THE BATH IS ADJUSTED TO BETWEEN 0.5 AND 3.0 G./L., AND WHEREBY THE FILAMENT WHICH HAS LEFT THE SECOND ROLLER IS RUN IN AIR PRIOR TO THE COMPLETION OF THE REGENERATION UNTIL ITS DEGREE OF REGENERATION REACHES BETWEEN 65 AND 85%.