Filler suspension and its use in the manufacture of paper

Abstract

Provided herein are filler suspensions comprising swollen cationic starch, anionic, water-soluble polymer and filler particles. Pulp furnishes comprising the filler suspensions and paper comprising the pulp furnish are also provided. Processes for making the filler suspensions and processes for their use in manufacturing paper are also provided.

What is claimed is: 
     
         1 . A filler suspension for use in papermaking, comprising:
 filler particles;   swollen cationic starch; and   anionic, water-soluble polymer.   
     
     
         2 . The filler suspensions of  claim 1 , wherein the anionic, water-soluble polymer is lightly cross-linked. 
     
     
         3 . The filler suspension of  claim 2 , wherein the anionic, lightly cross-linked, water-soluble polymer has a tan delta rheological oscillation value at 0.005 Hz of at least 0.5 in a 1.5% aqueous solution. 
     
     
         4 . The filler suspension of  claim 2 , wherein the anionic, lightly cross-linked, water-soluble polymer comprises sodium acrylate, acrylamide and methylenebisacrylamide. 
     
     
         5 . The filler suspension of  claim 1 , wherein the anionic, water-soluble polymer is TELIOFORM® M305. 
     
     
         6 . The filler suspension of  claim 2 , wherein the anionic, water-soluble polymer is TELIOFORM® M305. 
     
     
         7 . The filler suspension of  claim 1 , wherein the filler particles are selected from the group consisting of clay, talc, ground calcium carbonate, chalk, precipitated calcium carbonate, precipitated calcium sulfate, and combinations thereof. 
     
     
         8 . The filler suspension of  claim 1 , wherein the cationic starch granules are swollen with hot water at the gel point temperature of the cationic starch ±10° C., without cooking the cationic starch. 
     
     
         9 . The filler suspension of  claim 8 , wherein the temperature at which the cationic starch granules are swollen is the gel point temperature +10° C. 
     
     
         10 . The filler suspension of  claim 1 , wherein the filler particles have a size of 1-10 microns. 
     
     
         11 . The filler suspension of  claim 1 , wherein the swollen cationic, starch granules have a size of 25-100 microns. 
     
     
         12 . The filler suspension of  claim 1 , wherein the filler particles are present in an amount of 60 to 99.5% by weight, the swollen, cationic starch is present in an amount of 35 to 0.499% by weight and the anionic, water-soluble polymer is present in an amount of 5.0 to 0.001% by weight based on the total solids content of the filler suspension. 
     
     
         13 . A pulp furnish, comprising pulp fiber and the filler suspension of  claim 1 . 
     
     
         14 . The pulp furnish of  claim 13 , further comprising a co-additive selected from the group consisting of a sizing agent, a wet strength agent, a retention aid and combinations thereof. 
     
     
         15 . A paper comprising the pulp furnish of  claim 13 . 
     
     
         16 . A process for producing a filler suspension for papermaking, comprising contacting filler particles with swollen cationic starch and anionic, water-soluble polymer. 
     
     
         17 . The process of  claim 16 , wherein the anionic, water-soluble polymer is lightly cross-linked. 
     
     
         18 . A process of making paper comprising: contacting pulp fibers with the filler suspension of  claim 1  to form a pulp furnish; draining the pulp furnish through a wire to form a sheet; and drying the sheet. 
     
     
         19 . The process of  claim 18 , wherein the pulp furnish further includes a co-additive selected from the group consisting of a sizing agent, a wet strength agent, a dry strength agent, a retention aid and combinations thereof.