Solution containing cellulose dissolved in N-methylmorpholine-N-oxide and high tenacity lyocell multifilament using the same
This invention relates to a method of preparing cellulose solution which is homogeneous at relatively low temperature, in which a small amount of cellulose powder or polyvinylalcohol is dissolved in the liquid-state, concentrated N-methylmorpholine-N-oxide (hereinafter, referred to as ‘NMMO’) so as to lower the solidifying temperature of NMMO, and then, the resulting solution and cellulose powder are fed into an extruder so as to be mixed, swollen and melted in the extruder.
1. A method of preparing cellulose fiber, comprising the steps of:
(A) dissolving 0.01 to 3% by weight of cellulose powder in the liquid-state in a concentrated N-methylmorpholine-N-oxide (NMMO) solution to provide a cellulose-containing NMMO solution containing 0.01 to 3 wt % cellulose with respect to the total weight of the cellulose-containing NMMO solution, wherein the concentrated NMMO solution contains 10 to 18 wt % water with respect to the NMMO solution;
(B) feeding the cellulose-containing NMMO solution and additional cellulose powder into an extruder having a screw where the cellulose-containing NMMO solution and additional cellulose powder are subjected to dispersing, mixing, shearing, kneading, melting and measuring processes in the extruder so as to produce cellulose solution that is swollen and homogenized;
(C) spinning the cellulose solution through nozzle of a spinner, solidifying it through an aeration layer and solidifying bath to obtain multi-filament; and
(D) washing, drying, oil-treating and winding the obtained multi-filament.