Melt spun cellulose based fibers

Abstract

According to an example aspect of the present invention, there is provided a melt spinning method of cellulose based fibers with controlled molar masses and different side lengths, and continuous melt spun cellulose fibers thereof.

1 . A melt spinning method for preparing continuous cellulose-based fibers, comprising at least the steps of:
 preparing a molar mass controlled cellulose ester having a side chain length between C6 and C18, a total degree of substitution from 0.7 to 3, and a molar mass distribution between 30 and 300 kDa from a cellulose raw material comprising cellulose,   melt spinning the molar mass controlled cellulose ester to form melt spun fibers, and   collecting the melt spun fibers,   
       wherein the average molecular mass of the cellulose raw material is controlled via hydrolysis, excluding total hydrolysis. 
     
     
         2 . The method according to  claim 1 , wherein the cellulose raw material from a member selected from the group consisting of native softwood pulp, native hardwood pulp, annual plant pulp, softwood sulphite dissolving grade pulp, hardwood sulphite dissolving grade pulp, ozone treated hydrolyzed pulp, and enzyme treated pulp. 
     
     
         3 . The method according to  claim 1 , when the hydrolysis is controlled so that the average molecular mass of the cellulose is reduced at least 60% but not more than 85% from the molecular mass of the cellulose raw material, wherein, after the hydrolysis, the average molecular mass of the cellulose is in a range between 40 and 200 kDa. 
     
     
         4 . The method according to  claim 1 , wherein the cellulose raw material is hydrolyzed by enzymatic treatment, ozone treatment, hydrogen peroxide treatment, alkaline treatment or other chemical treatment. 
     
     
         5 . The method according to  claim 1 , wherein the molar mass controlled cellulose ester is prepared by homogenous esterification of the cellulose raw material by adding fatty acid chloride to the cellulose raw material using pyridine as catalyst at a reaction temperature of 80° C. and for a reaction time of 16 hours. 
     
     
         6 . The method according to  claim 1 , wherein the melt spinning is performed at a temperature between 120 and 150° C. using a melt spinning device having a single screw extruder, a melt pump, and a multi strand filament die. 
     
     
         7 . The method according to  claim 1 , wherein the melt spun fibers are collected using a drawing speed of 0 to 200 m/min. 
     
     
         8 . The method according to  claim 1 , wherein the molar mass controlled cellulose ester has a side chain length between C6 and C16. 
     
     
         9 . The method according to  claim 1 , wherein the molar mass controlled cellulose ester has a total degree of substitution between 0.9 and 2.0. 
     
     
         10 . A fully bio-based continuous melt spun molar mass controlled cellulose fiber having a thickness of at least 75 μm. 
     
     
         11 . The continuous melt spun molar mass controlled cellulose fiber according to  claim 10 , further comprising a tenacity of below 0.5 cN/dtex. 
     
     
         12 . The continuous melt spun molar mass controlled cellulose fiber according to  claim 10 , further an elongation of at least 5%. 
     
     
         13 . The continuous melt spun molar mass controlled cellulose fiber according to  claim 10 , wherein the fiber is manufactured according to the method of  claim 1 . 
     
     
         14 . A textile, fiber, filament, yarn, or cloth comprising a plurality of the continuous melt spun molar mass controlled cellulose fibers of  claim 10 .