PROCESS FOR PRODUCING CELLULOSE MULTI-FILAMENT WITH LOWER COEFFICIENT OF VARIATION OF SECTION DIAMETER

摘要

The present invention relates to a cellulose fiber having a highly homogeneous section, particularly to a cellulose fiber with lower Coefficient of Variation of section diameter (CV(%)). Specifically, the present invention relates to a cellulose fiber wherein Coefficient of Variation of section diameter (CV(%)) of a mono-filament constituting a multi-filament prepared by dissolving a cellulose powder in liquid N-methylmorpholine N-oxide(hereinafter referred to "NMMO") is below 2.5. According to the present invention, a lyocell multi-filament is produced comprising the steps of (i)preparing a spinning solution by homogeneously dispersing, swelling and dissolving cellulose powder in a NMMO solution; (ii)spinning the spinning solution into an air gap through a spinning nozzle; and (iii)coagulating the extruded-spun spinning solution in a coagulation bath. In particular, the coagulating step is adjusted by means of a coagulation coefficient in the range of 0.8 to 1.3 and the coagulation coefficient is expressed as T _D/T_C, T_D= T_D + T_A 90 and T_D T_AandT_c mean the temperature of a spinning solution, the temperature of cooling air applied in an air gap and the temperature of a coagulation bath, respectively.