Method of modifying starch for increased papermachine retention and drainage performance

Abstract

A method of modifying starch with metal silicates, and the use of the modified starch in the preparation of cellulosic fiber compositions. The method further relates to cellulosic fiber compositions, such as paper and paperboard, which incorporate the starch modified with metal silicates.

1 . A papermaking process comprising adding to a papermaking slurry, at least one polysaccharide or polysaccharide derivative, wherein the polysaccharide or polysaccharide derivative has been modified with at least one metal silicate, wherein the at least one polysaccharide or polysaccharide derivative is selected from the group consisting of derivatized polysaccharides containing a cationic nitrogen group, a blend of cationic and anionic polysaccharides or combinations thereof. 
     
     
         2 . The method of  claim 1  wherein the at least one polysaccharide or polysaccharide derivative comprises a least one starch. 
     
     
         3 . The method of  claim 2  where the starch is selected from the group consisting of a potato starch; corn starch; wheat starch; tapioca starch; rice starch; derivatives thereof and combinations thereof. 
     
     
         4 . The method of  claim 1  where the at least one metal silicate is selected from the group consisting of sodium silicate, potassium silicate, sodium metasilicate or combinations thereof 
     
     
         5 . The method of  claim 4  wherein the metal silicate is sodium silicate. 
     
     
         6 . The method of  claim 1  wherein the ratio of polysaccharide to metal silicate is from 1:10 to 100:1. 
     
     
         7 . The method of  claim 6  where the ratio of polysaccharide to metal silicate is from 1:1 to 50:1. 
     
     
         8 . A papermaking process comprising adding to a papermaking slurry, at least one starch or starch derivative, wherein the starch or starch derivative has been modified with a metal silicate, wherein the at least one starch or starch derivative is selected from the groups consisting of derivatized starch containing a cationic nitrogen group or a blend of cationic and anionic starches. 
     
     
         9 . The method of  claim 7  where the starch is selected from the group consisting of potato starch; corn starch; wheat starch; tapioca starch; rice starch; derivatives thereof and combinations thereof. 
     
     
         10 . The method of  claim 7  wherein the metal silicate is selected from the group consisting of sodium silicate, potassium silicate, sodium metasilicate and combinations thereof. 
     
     
         11 . The method of  claim 7  wherein the ratio of starch to metal silicate is from 1:10 to 100:1. 
     
     
         12 . The method of  claim 11  wherein the ratio of starch to metal silicate is from 1:1 to 50:1.