Method for producing cellulose fiber having improved biostability and the resulting products

Abstract

A cellulose fiber having extended biostability and the method of its manufacture are described. While prior treatments of cellulose with biotoxic metal compounds have given improved resistance to decay, these treatments have not been entirely satisfactory where the fiber had to be refined before use. Refining energy was very high and fiber length loss was substantial. Treatment of cellulose fiber with didecyldimethylammonium chloride (DDAC) or bromide (DDAB), these materials in combination with low levels of copper, or low levels of copper alone, has given a product with very good biostability without a major increase in refining energy or loss of fiber length. The treated fiber is particularly advantageous as a reinforcing component for cement board products.

1 . A fibrous cellulose product resistant to biological degradation which comprises cellulose fibers treated with a biocidally effective amount of a compound selected from the group consisting of didecyldimethylammonium chloride, didecyldimethylammonium bromide, water soluble copper salts, and mixtures thereof.  
     
     
         2 . The cellulose product of  claim 1  in which the fiber is treated with 0.01-0.25% of a water soluble copper salt.  
     
     
         3 . The cellulose product of  claim 1  or  2  in which the fiber is treated with 0.1-2.0% didecyldimethylammonium chloride.  
     
     
         4 . The cellulose product of  claim 1  or  2  in which the fiber is treated with 0.1-2.0% didecyldimethyl ammonium bromide.  
     
     
         5 . The cellulose product of  claim 1  in which the cellulose fiber is an unbleached kraft fiber.  
     
     
         6 . A method for producing a cellulose fiber resistant to biological degradation which comprises: 
 providing a cellulose fiber that has been at least partially purified by a chemical pulping process;    treating the fiber with biocidally effective amount of a biocidal composition selected from the group consisting of didecyldimethylammonium chloride, didecyldimethylammonium bromide, water soluble copper salts, and mixtures thereof; and drying the fiber.    
     
     
         7 . The method of  claim 6  in which the fiber is treated with 0.01-0.25% of a water soluble copper salt.  
     
     
         8 . The method of  claim 6  or  7  in which the fiber is treated with 0.1-2.0% didecyldimethylammonium chloride.  
     
     
         9 . The method of  claim 6  or  7  in which the fiber is treated with 0.1-2.0% didecyldimethylammonium bromide.  
     
     
         10 . The method of  claim 6  in which the cellulose fiber is an unbleached kraft fiber.  
     
     
         11 . The method of  claim 6  in which the treated fiber is sheeted prior to drying.