Lyocell multi-filament for tire cord and method of producing the same

Abstract

Disclosed is a lyocell multi-filament for a tire cord and a method of producing the same. The method includes i) dissolving mixed powder of cellulose and polyvinyl alcohol in a mixed solvent of N-methyl morpholine N-oxide and water to prepare a dope, ii) extruding the dope using a spinning nozzle including orifices through air gaps into a conical upper coagulation bath to solidify the dope to produce a multi-filament, iii) feeding the multi-filament through a lower coagulation bath to a washing bath, and washing the multi-filament, and iv) drying and oiling the washed multi-filament and winding the resulting multi-filament. At this time, the orifices each have a diameter (D) of 100 to 300 μm, a length (L) of 200 to 2400 μm, and a ratio of the length to the diameter (L/D) of 2 to 8, and are spaced apart from each other at intervals of 2.0 to 5.0 mm. The method provides a lyocell multi-filament having excellent physical properties useful as a tire cord, thereby producing a tire for an automobile having improved driving stability, dimensional stability, and uniformity using the tire cord.

1 . A method of producing a lyocell multi-filament for a tire cord, comprising: 
 i) dissolving mixed powder of cellulose and polyvinyl alcohol in a mixed solvent of N-methyl morpholine N-oxide and water to prepare a dope;    ii) extruding the dope using a spinning nozzle including orifices through air gaps into a conical upper coagulation bath to coagulate the dope to produce a multi-filament, said orifices each having a diameter (D) of 100 to 300 μm, a length (L) of 200 to 2400 μm, and a ratio of the length to the diameter (L/D) of 2 to 8, and being spaced apart from each other at intervals of 2.0 to 5.0 mm;    iii) feeding the multi-filament through a lower coagulation bath to a washing bath, and washing the multi-filament; and    iv) drying and oiling multi-filament and winding the resulting multi-filament.    
     
     
         2 . The method as set forth in  claim 1 , wherein polyvinyl alcohol of the mixed powder of cellulose and polyvinyl alcohol has a degree of polymerization of 1000 to 4000, and the mixed powder contains 0.5 to 30 wt % polyvinyl alcohol.  
     
     
         3 . The method as set forth in  claim 1 , wherein the air gaps are spaced apart from each other at intervals of 20 to 300 mm, cooling air at 5 to 20° C. is fed into the air gaps, and the relative humidity (RH) of each of the air gaps is maintained from 10 to 50%.  
     
     
         4 . The method as set forth in  claim 1 , in the spinning nozzle comprises 500 to 1500 orifices.  
     
     
         5 - 16 . (canceled)