Aluminum trihydrate containing slurries

Abstract

The present invention relates to Aluminum trihydrate slurries comprising aluminum trihydrate particles, an acrylic dispersant, citric acid, synthetic hectorite clay, optionally a compound to adjust pH, a biocide and water. These slurries may be mixed with titanium dioxide slurries to produce a stable slurry blends useful in paper and paper-board applications.

What is claimed is:  
     
         1 . An aqueous slurry comprising pigmentary aluminum trihydrate, aluminum trihydrate slurries comprising: 
 (a) at least 50% by weight of the slurry of dispersed aluminum trihydrate particles having an average particle size of at least 0.5 micron;    (b) a dispersant comprising an acrylic dispersing resin, and optionally citric acid;    (c) a synthetic hectorite clay;    (d) optionally a compound to adjust pH;    (e) a biocide; and    (f) water.    
     
     
         2 . The slurry of  claim 1  wherein the slurry is FDA compliant for indirect food contact.  
     
     
         3 . The slurry of  claim 1  comprising at 67-68% by weight dispersed aluminum trihydrate pigmentary particles.  
     
     
         4 . A blended slurry comprising an aqueous slurry of pigmentary rutile titanium dioxide particles and an aqueous pigmentary aluminum trihydrate slurry comprising: 
 (a) at least 50% by weight of dispersed aluminum trihydrate pigmentary particles having an average particle size of at least 0.5 micron;    (b) a dispersant comprising an acrylic dispersing resin, and optionally citric acid;    (c) a synthetic hectorite clay;    (d) optionally a compound to adjust pH;    (e) a biocide; and    (f) water.    
     
     
         5 . The slurry of  claim 4  wherein the weight percentage of the rutile titanium dioxide slurry is from about 75 to about 50% and the weight percentage of the aluminum trihydrate slurry is from about 25 to about 50%.  
     
     
         6 . A process for making paper comprising mixing pulp and the slurry of  claim 5  to form a stock and dewatering and drying the stock to form a sheet.  
     
     
         7 . A paper coating having as the titanium dioxide containing component an aqueous slurry of pigmentary rutile titanium dioxide particles and an aqueous pigmentary aluminum trihydrate slurry comprising: 
 (a) at least 50% by weight of dispersed aluminum trihydrate pigmentary particles having an average particle size of at least 0.5 micron;    (b) a dispersant comprising an acrylic dispersing resin, and optionally citric acid;    (c) a synthetic hectorite clay;    (d) optionally a compound to adjust pH;    (e) a biocide; and    (f) water.