ALKALI RECYCLE IN CELLULOSE SPINNING PROCESS

摘要

The present invention concerns a method for the recovery of solvent in a process for preparation of regenerated cellulosic fibers using sodium hydroxide as solvent for cellulose dissolving in the manufacturing of a cellulose spinning dope wherein sodium hydroxide present in the spinning dope is at least partially recovered and recycled as sodium hydroxide from a cellulose fiber regeneration or cellulose coagulation step and wherein said cellulose fiber regeneration or cellulose coagulation step consists of a bath into which cellulose spinning dope is injected. Recovered sodium hydroxide may be directly or indirectly recycled from a cellulose fiber regeneration or cellulose coagulation step to a cellulose dissolving step.

主权项

1. Method for the recovery of sodium hydroxide in a process for preparation of regenerated cellulosic fibers using aqueous sodium hydroxide as solvent for cellulose or cellulose derivatives dissolving in the manufacture of a cellulosic spinning dope, wherein sodium hydroxide present in the cellulosic spinning dope is at least partially recovered as sodium hydroxide from a coagulation bath into which the cellulosic spinning dope is injected, and wherein die-swell of filaments and coagulation rate of cellulosic moieties in the coagulation bath is controlled by adjusting a spinneret hole diameter (D) and land length (L) to a L/D ratio below 4, and preferably in the range of 0.1-2.