Method of producing cellulose carbamate fibre and use of the same

Abstract

The invention relates to a cellulose carbamate spinning solution, cellulose fibres and a method for the production thereof in which a solution of cellulose carbamate in an ionic liquid is pressed through the holes of a spinning nozzle. The shaped fibres are stretched in air and the cellulose carbamate is regenerated in an aqueous bath. Solvent is removed by washing and the fibre is subsequently dried.

1 .- 9 . (canceled) 
   
   
       10 . A method of producing spun cellulose carbamate fibres, comprising
 (a) pressing a spinning solution through a spinning nozzle which has at least one opening, to form a spinning solution thread, wherein the spinning solution is a cellulose carbamate spinning solution comprising a solution of cellulose carbamate in at least one ionic liquid, wherein the cellulose carbamate concentration of the spinning solution is at least 15% by weight and the zero shear viscosity, measured at 100° C., is in the range of 50 to 7,500 Pas;   (b) stretching the spinning solution thread in an air gap; and   (c) subsequently coagulating the spinning solution thread in a precipitation bath.   
   
   
       11 . The method of  claim 10 , wherein the 1/d ratio of the spinning nozzle is from 2 to 20. 
   
   
       12 . The method of  claim 10 , wherein the width of the air gap is from 5 to 250 mm. 
   
   
       13 . The method of  claim 10 , wherein an aqueous solution of at least one ionic liquid is used in the precipitation bath. 
   
   
       14 . The method of  claim 13 , wherein the weight concentration of the at least one ionic liquid in the aqueous solution is from 0.5 to 50% by weight. 
   
   
       15 . The method of  claim 10 , wherein the temperature of the spinning solution is from 50 to 150° C. 
   
   
       16 . Cellulose carbamate fibre, produced by the method of  claim 10 . 
   
   
       17 . The fibre of  claim 16 , wherein the fibre has a strength of at least 30 cN/tex measured according to DIN 53834. 
   
   
       18 . The fibre of  claim 16 , wherein the fibre has a modulus of elasticity of at least 1,500 cN/tex. 
   
   
       19 . The fibre of  claim 16 , wherein the fibre has a nitrogen content between 0.01 and 7% by weight. 
   
   
       20 . A precursor for industrial fibres comprising the fibre of  claim 16 . 
   
   
       21 . A reinforcing fibre for plastic materials or composites comprising the fibre of  claim 16 . 
   
   
       22 . The method of  claim 10 , wherein the ionic liquid has a melting point below 100° C. 
   
   
       23 . The method of  claim 10 , wherein the ionic liquid is selected from the group consisting of ammonium-, pyrazolium-, cholinium-, in 1- and 3-position alkyl- or aryl-substituted imidazolium compounds, and mixtures thereof. 
   
   
       24 . The method of  claim 23 , wherein the ionic liquid is selected from the group consisting of butyl methylimidazolium acetate, butyl methylimidazolium chloride, ethyl methylimidazolium chloride, ethyl methylimidazolium acetate, butyl ethylimidazolium acetate, butyl ethylimidazolium chloride, methyl tetradecylimidazolium chloride, butyl methylimidazolium bromide, butyl methylpyridinium chloride, butyl methylimidazolium thiocyanate, ethyl methylimidazolium thiocyanate, butyl ethylimidazolium thiocyanate, hexyl dimethylimidazolium hexafluoroborate, ethoxy methyl methylpyrrolidinium chloride, hydroxypropyl methylimidazolium acetate, hydroxypropyl methylimidazolium chloride, butyl methylpyridinium chloride, and mixtures thereof. 
   
   
       25 . The method of  claim 10 , wherein the cellulose carbamate has a DP cuoxam  of 150 to 750. 
   
   
       26 . The method of  claim 10 , wherein the cellulose carbamate has a substitution degree DS carbamate  of 0.1 to 1. 
   
   
       27 . The method of  claim 10 , wherein the cellulose carbamate concentration is between 20 and 50% by weight. 
   
   
       28 . The method of  claim 10 , wherein dried cellulose carbamate is used for the production of the spinning solution. 
   
   
       29 . The method of  claim 10 , wherein water-containing cellulose carbamate is used for the production of the spinning solution and the dissolving process is implemented at a reduced pressure of less than 0.9 bar. 
   
   
       30 . The method of  claim 10 , wherein the zero shear viscosity, measured at 100° C., is in the range of 50 to 5,000 Pas.