Method for Producing Cellulose Fiber

Abstract

The present invention relates to a method for producing a cellulose solution which is homogeneous at low temperatures, and to fiber produced by the method. More particularly, the invention relates to a production of a cellulose solution which is homogeneous at low temperatures, by dissolving a small amount of the cellulose powder in concentrated liquid N-methylmorpholine-N-oxide (NMMO) to lower the solidification temperature of NMMO, introducing the low-temperature, concentrated liquid NMMO solution having cellulose dissolved and the cellulose powder into a kneader, mixing and swelling the cellulose in the kneader without a process of reducing pressure to produce a paste, and then supplying the paste into an extruder to dissolve the paste in a homogeneous solution.

1 . A method for producing a cellulose fiber comprising the steps of:
 (A) preparing an N-methylmorpholine-N-oxide solution by dissolving a cellulose powder in concentrated liquid-state N-methylmorpholine-N-oxide (NMMO) to a small amount of 0.01 to 5% by weight;   (B) introducing the N-methylmorpholine-N-oxide solution having a small amount of the cellulose powder dissolved and cellulose powder into a kneader, mixing, swelling and partially dissolving the cellulose in the kneader without reducing the pressure to produce a paste, and then feeding the paste to an extruder to obtain a homogenized cellulose solution;   (C) spinning the cellulose solution by extrusion through a spinning nozzle, and then solidifying the spun cellulose solution which has reached a solidifying bath through an air bed to obtain a multi-filament; and   (D) washing, drying, oil-treating and winding the obtained multi-filament.   
     
     
         2 . The method for producing a cellulose fiber according to  claim 1 , wherein the liquid-state N-methylmorpholine-N-oxide having a small amount of cellulose dissolved is maintained at a temperature of 50° C. to 95° C. in the step (A). 
     
     
         3 . The method for producing a cellulose fiber according to  claim 1 , wherein the kneader into which the N-methylmorpholine-N-oxide solution having a small amount of cellulose dissolved are introduced is maintained at 50° C. to 95° C. in the step (B). 
     
     
         4 . The method for producing a cellulose fiber according to  claim 1 , wherein the final cellulose solution prepared by dissolution in the extruder in the step (B) contains cellulose at a concentration of 5 to 20% by weight with respect to the total weight of the solution. 
     
     
         5 . The method for producing a cellulose fiber according to  claim 1 , wherein the N-methylmorpholine-N-oxide solution at the step (A) contains moisture in an amount of 10 to 18% by weight with respect to the total weight of the solution. 
     
     
         6 . The method for producing a cellulose fiber according to  claim 1 , wherein the liquid-state N-methylmorpholine-N-oxide having a small amount of cellulose dissolved is supplied to the kneader while being maintained at a temperature of 50° C. to 95° C. in the step (B). 
     
     
         7 . The method for producing a cellulose fiber according to  claim 1 , wherein the cellulose powder at the step (A) or step (B) is mixed with other polymer materials.