Method for producing carbon fibers from cellulose fibers

Abstract

A method of producing carbon fibers from cellulose fibers comprises bringing cellulose fibers having a water content of more than 20 parts by weight of water per 100 parts by weight of cellulose fiber into contact with a solution of additives and thereafter converting the additized cellulose fibers comprising not less than 1 part by weight of additives per 100 parts by weight of cellulose into carbon fibers.

1 . A method of producing carbon fibers from cellulose fibers, comprising:
 contacting cellulose fibers comprising more than 20 parts by weight of water per 100 parts by weight of cellulose fiber with a solution comprising an additive such that additized cellulose fibers comprising not less than 1 part by weight of an additive per 100 parts by weight of cellulose are produced; and   converting the additized cellulose fibers into carbon fibers.   
     
     
         2 . The method according to  claim 1 , wherein the cellulose fibers comprise more than 50 parts by weight of water per 100 parts by weight of cellulose. 
     
     
         3 . The method according to  claim 1 , wherein the cellulose fibers are obtained by the process comprising
 spinning raw material cellulose fibers from a spinning solution, and   washing the spun raw material cellulose fibers with water.   
     
     
         4 . The method according to  claim 3 , wherein the process does not comprise drying the raw material cellulose fibers or the spun raw material cellulose. 
     
     
         5 . The method according to  claim 1 , wherein the solution comprises water, a hydrophilic organic solvent or mixtures thereof. 
     
     
         6 . The method according to  claim 1 , wherein the additive comprises a compound having a water solubility of not less than 10 parts by weight per 100 parts by weight of water under standard conditions (20° C., 1 bar). 
     
     
         7 . The method according to  claim 1 , wherein the additive comprises a salt or an acid. 
     
     
         8 . The method according to  claim 1 , wherein the contacting comprises leading the cellulose fibers through the solution in a continuous manner such that a contact time is not less than 2 seconds. 
     
     
         9 . The method according to  claim 1 , wherein the additized cellulose fibers comprise not less than 5 parts by weight of the additive per 100 parts by weight of cellulose. 
     
     
         10 . The method according to  claim 1 , wherein the additized cellulose fibers are converted into a the carbon fibers by pyrolysis. 
     
     
         11 . The method according to  claim 1 , further comprising:
 producing the cellulose fibers by a process comprising spinning raw material cellulose fibers from a spinning solution, and washing the spun raw material cellulose fibers with water.   
     
     
         12 . The method according to  claim 11 , wherein the process for producing the cellulose fibers does not comprise drying the raw material cellulose fibers or the spun raw material cellulose. 
     
     
         13 . The method according to  claim 10 , wherein the pyrolysis is performed at a temperature of from 500 to 1600° C. 
     
     
         14 . The method according to  claim 10 , wherein the pyrolysis is performed by heating the additized cellulose fibers while increasing a temperature from 200° C. to 1200° C. 
     
     
         15 . The method according to  claim 1 , further comprising:
 drying the carbon fibers at a temperature of from 50 to 300° C.