Method for the production of oxidized cellulose fibers, oxidized cellulose fiber sheet materials or oxidized cellulose nonwovens, and use thereof

Abstract

A method for the production of at least one of oxidized cellulose fibers, oxidized cellulose fiber sheet materials and oxidized cellulose nonwovens includes introducing at least one of cellulose fibers, cellulose fiber sheet materials and cellulose nonwovens into a reactor. A temperature of the reactor is set in a range from 25° C. to 80° C. Gaseous nitrogen dioxide is introduced into the reactor so as to oxidize the at least one of cellulose fibers, cellulose fiber sheet materials and cellulose nonwovens. A temperature of the reactor is set in a range from 20° C. to less than 160° C. The at least one of oxidized cellulose fibers, oxidized cellulose fiber sheet materials and oxidized cellulose nonwovens are neutralized with at least one base.

1 - 9 . (canceled) 
     
     
         10 . A method for the production of at least one of oxidized cellulose fibers, oxidized cellulose fiber sheet materials and oxidized cellulose nonwovens, the method comprising:
 a) introducing at least one of cellulose fibers, cellulose fiber sheet materials and cellulose nonwovens into a reactor;   b) setting a temperature of the reactor in a range from 25° C. to 80° C.;   c) introducing gaseous nitrogen dioxide into the reactor so as to oxidize the at least one of cellulose fibers, cellulose fiber sheet materials and cellulose nonwovens;   d) setting a temperature of the reactor in a range from 20° C. to less than 160° C.; and   e) neutralizing the at least one of oxidized cellulose fibers, oxidized cellulose fiber sheet materials and oxidized cellulose nonwovens with at least one base.   
     
     
         11 . The method according to  claim 10 , wherein step c) is performed to provide a degree of oxidation between 1% and 50%. 
     
     
         12 . The method according to  claim 11  wherein the degree of oxidation is between 5% and 35%. 
     
     
         13 . The method according to  claim 10 , wherein the temperature in step b) is in a range from 30° C. to 60° C. 
     
     
         14 . The method according to  claim 10 , wherein the temperature in step d) is not more than 100° C. 
     
     
         15 . The method according to  claim 10 , wherein the at least one base includes gaseous ammonia. 
     
     
         16 . The method according to  claim 10 , wherein the at least one of cellulose fibers, cellulose fiber sheet materials and cellulose nonwovens have a fiber fineness of 0.5 dtex to 30 dtex and a fiber length between 3 mm and 120 mm. 
     
     
         17 . The method according to  claim 10 , wherein the at least one of cellulose fibers, cellulose fiber sheet materials and cellulose nonwovens have a moisture content of 7% by weight at the maximum. 
     
     
         18 . The method according to  claim 10 , farther comprising adding at least one additive including at least one of synthetic polymers, biopolymers, active ingredients and special additives to the at least one of oxidized cellulose fibers, oxidized cellulose fiber sheet materials and oxidized cellulose nonwovens, 
     
     
         19 . The method according to claim  4 , wherein the at least one additive includes at least one of polyvinyl alcohols, polyolefins, polyethylene glycols, polyesters, medications and agents that promote wound healing. 
     
     
         20 . The method according to  claim 10 , wherein the gaseous nitrogen dioxide is used without the addition of halogenated hydrocarbons and is circulated. 
     
     
         21 . The method according to  claim 10 , wherein a pressure of the reactor is in a range from 0.1 bar to 7 bar, 
     
     
         22 . The method according to  claim 21 , wherein the pressure is in a range from 0.8 bar to 3 bar. 
     
     
         23 . Oxidized cellulose fibers, oxidized cellulose fiber sheet materials or oxidized cellulose nonwovens produced by a method according to  claim 10 , which exhibit an absorption of an aqueous 0.9% sodium chloride solution in a range from 400% to 10,000% by weight. 
     
     
         24 . A method of using at least one of oxidized cellulose fibers, oxidized cellulose fiber sheet materials and oxidized cellulose nonwovens produced by the method according to  claim 10 , for a medical sector, as or for at least one of wound dressings, tissue constructions, tissue growing, tissue engineering, implants, packaging, cosmetic, hygiene or household products, cleaning supplies and filters, insulating substances and support materials, catalysts, furniture, clothing, interlinings, interfacing, noise and heat protection.