Bleached crosslinked cellulosic fibers having high color and related methods

Abstract

Whitened crosslinked cellulosic fibers, methods for making the fibers, and products that include the fibers.

1 . Whitened crosslinked cellulosic fibers, comprising cellulosic fibers treated with a crosslinking agent, a whitening agent comprising one or more dyes, and a bleaching agent.  
   
   
       2 . The fibers of  claim 1 , wherein the fibers are treated with an amount of the crosslinking agent, the whitening agent, and the bleaching agent sufficient to provide crosslinked fibers having increased whiteness compared to crosslinked fibers that have not been treated with the whitening agent and bleaching agent.  
   
   
       3 . The fibers of  claim 1 , wherein the whitening agent comprises a blue dye.  
   
   
       4 . The fibers of  claim 3 , wherein the blue dye is an azo dye.  
   
   
       5 . The fibers of  claim 3 , wherein the blue dye is an azo metal complex dye.  
   
   
       6 . The fibers of  claim 1 , wherein the crosslinked cellulosic fibers comprise citric acid crosslinked cellulosic fibers.  
   
   
       7 . The fibers of  claim 1 , wherein the bleaching agent comprises hydrogen peroxide.  
   
   
       8 . The fibers of  claim 1 , wherein the bleaching agent comprises hydrogen peroxide in combination with sodium hydroxide.  
   
   
       9 . A method for making whitened crosslinked cellulosic fibers, comprising: 
 applying a whitening agent, crosslinking agent, and optionally a crosslinking catalyst to a web of pulp fibers to provide a web of treated fibers;    separating the web of treated fibers into individualized treated fibers;    heating the individualized treated fibers at a temperature and for a time sufficient to provide individualized crosslinked fibers; and    applying a bleaching agent to the crosslinked fibers to provide whitened crosslinked fibers.    
   
   
       10 . The method of  claim 9 , wherein the whitening agent comprises a blue dye.  
   
   
       11 . The method of  claim 10 , wherein the blue dye is an azo dye.  
   
   
       12 . The method of  claim 10 , wherein the blue dye is an azo metal complex dye.  
   
   
       13 . The method of  claim 9 , wherein the crosslinking agent comprises citric acid.  
   
   
       14 . The method of  claim 9 , wherein the crosslinking catalyst comprises sodium hypophosphite.  
   
   
       15 . The method of  claim 9 , wherein the bleaching agent comprises hydrogen peroxide.  
   
   
       16 . The method of  claim 9 , wherein the bleaching agent comprises hydrogen peroxide in combination with sodium hydroxide.  
   
   
       17 . An absorbent product, comprising the fibers of  claim 1 .  
   
   
       18 . The product of  claim 17 , wherein the product is a wipe, tissue, or towel.  
   
   
       19 . The product of  claim 17 , wherein the product is an infant diaper, adult incontinence product, or feminine hygiene product.