Roller surface

Abstract

The present invention relates to the surface adaptation of a roller to be employed in the production of cellulose filament yarns.

1 . A roller, suitable to be used during lyocell filament production, wherein a surface of the roller comprises first sections displaying a surface tension so that, depending on a liquid adhering to a filament or yarn, one of the following conditions is fulfilled:
 a) surface tension of the first sections is in the range of from 0.25 to 3.5 times, optionally 0.35 to 2.5, or optionally 0.4 to 0.8 times the surface tension of the liquid, provided that the surface tension of the liquid is 45 mN/m or more; or   b) the surface tension of the first sections is in the range of from 0.5 to 10 times, optionally 0.8 to 2.5, or optionally more preferably 1 to 2 times the surface tension of the liquid, provided that the surface tension of the liquid is less than 45 mN/m.   
     
     
         2 . A method of selecting a roller according to  claim 1  for a process step during lyocell filament production. 
     
     
         3 . The roller according to  claim 1 , wherein the surface tension of the first sections is so that the following condition is fulfilled: the surface tension of the first sections of condition a) is in the range of from 1 to 1.75 times; the surface tension of the first sections of condition b) is in the range of from 0.9 to 5 times the surface tension of the liquid. 
     
     
         4 . The roller according to  claim 1 , wherein the roller surface comprises second sections having a surface tension lower than the first sections. 
     
     
         5 . The roller according to  claim 1 , wherein the first sections are made from metal, optionally chromium plated steel. 
     
     
         6 . The roller according to  claim 4 , wherein the second sections are made from synthetic polymers. 
     
     
         7 . The roller according to  claim 4 , wherein the second sections are creases or grooves. 
     
     
         8 . The roller according to  claim 4 , wherein the roller surface comprises only the first sections or wherein the first sections and the second sections substantially extend parallel along an axis of the roller. 
     
     
         9 . The roller according to  claim 4 , wherein the second sections show a breadth of from 0.5 to 5 mm, optionally of from 1.5 to 2.5 mm. 
     
     
         10 . The roller according to  claim 4 , wherein the second sections are spaced apart by 2 to 25 mm, optionally 3 to 4.5 mm. 
     
     
         11 . The roller according to  claim 1 , wherein the first sections amount to from 40 to 95% of a surface area of the roller surface. 
     
     
         12 . (canceled) 
     
     
         13 . The roller according to  claim 1 , wherein the roller is used as a guidance roller taking up lyocell filaments or filament bundles after these exit a coagulation bath. 
     
     
         14 . The roller according to  claim 1 , wherein the roller is employed during liquid removal and/or washing steps. 
     
     
         15 . The roller according to  claim 1 , wherein the roller is used during application of additional substances to the filament.