Process for bleaching pulp or paper

Abstract

A process for bleaching substantially lignin-free pulp or paper in a single-stage bleaching process or multi-stage bleaching process; comprising contacting said substantially lignin-free pulp or paper with an aqueous reductive bleaching solution comprising hydroxymethane sulfinic acid during a reductive bleaching stage for sufficient amount of time to at least partially bleach said substantially lignin-free pulp or paper.

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         14 . An aqueous reductive bleach solution comprising hydroxymethane sulfinic acid with at least one bleaching initiator.  
     
     
         15 . The aqueous reductive bleach solution of  claim 14  wherein the bleaching initiator is selected from the group consisting of one or more sugars, alum and mixtures thereof.  
     
     
         16 . The aqueous reductive bleach solution of  claim 14  wherein the weight ratio of hydroxymethane sulfinic acid to the at least one bleaching initiator is from about 1:20 to about 20:1.  
     
     
         17 . The aqueous reductive bleach solution of  claim 14  additionally containing at least one second reductive bleaching agent.  
     
     
         18 . The aqueous reductive bleach solution of  claim 17  wherein the second reductive bleaching agent is selected from the group consisting of sodium hydrosulfite, and formamidine sulfinic acid and mixtures thereof wherein the weight ratio of hydroxymethane sulfinic acid to the second reductive bleaching agent is from about 1:20 to about 20:1.