Method of preparing an aggregate metal oxide particle dispersion having a desired aggregate particle diameter

Abstract

The invention provides an aqueous dispersion of aggregate silica particles comprising aggregate silica particles having an aggregate structure comprised of fused primary particles, wherein the aggregate silica particles have a primary particle diameter and an aggregate particle diameter, and the average of the primary particle diameters (d p ), the number average of the aggregate particle diameters (D circ ave ) and the geometric standard deviation of the aggregate particle diameters (σ g (D circ )) satisfies at least one of the two following equations: (1) D circ ave (nm)<52+2d p (nm) for silica, and (2) σ g (D circ )<1.44+0.011d p (nm) for silica. The invention also provides an aqueous dispersion of aggregate alumina particles.

1 . An aqueous dispersion of aggregate silica particles comprising aggregate silica particles having an aggregate structure comprised of fused primary particles, wherein the aggregate silica particles have a primary particle diameter and an aggregate particle diameter, and the average of the primary particle diameters (d p ), the number average of the aggregate particle diameters (D circ ave ) and the geometric standard deviation of the aggregate particle diameters (σ g (D circ )) satisfies at least one of the two following equations:
     D   circ ave (nm)<52+2 d   p (nm) for silica, and  (1)     σ g ( D   circ )<1.44+0.011 d   p (nm) for silica.  (2)   
     
     
         2 . The dispersion of  claim 1 , wherein equation (1) is satisfied. 
     
     
         3 . The dispersion of  claim 1 , wherein equation (2) is satisfied. 
     
     
         4 . The dispersion of  claim 1 , wherein both equations (1) and (2) are satisfied. 
     
     
         5 . The dispersion of  claim 1 , wherein the geometric standard deviation of the aggregate particle diameters σ g (D circ ) satisfies the following equation:
   1.44+0.011 d   p (nm)>σ g ( D   circ )>1.3+0.011 d   p (nm) for silica.   
     
     
         6 . The dispersion of  claim 1 , wherein the dispersion has a solids concentration of about 5-50 wt. %. 
     
     
         7 . The dispersion of  claim 6 , wherein the dispersion has a solids concentration of about 15-40 wt. %. 
     
     
         8 . The dispersion of  claim 1 , wherein the dispersion comprises a stabilizer selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium hydroxide, triethylamine, and dimethylethanol amine. 
     
     
         9 . The dispersion of  claim 8 , wherein the dispersion has a pH of about 8-13. 
     
     
         10 . The dispersion of  claim 9 , wherein the dispersion has a pH of about 9-12. 
     
     
         11 . An aqueous dispersion of aggregate alumina particles comprising aggregate alumina particles having an aggregate structure comprised of fused primary particles, wherein the aggregate alumina particles have a primary particle diameter and an aggregate particle diameter, and the average of the primary particle diameters (d p ), the number average of the aggregate particle diameters (D circ ave ), and the geometric standard deviation of the aggregate particle diameters (σ g (D circ )) satisfies at least one of the two following equations:
     D   circ ave (nm)<35+1.8 d   p (nm), and  (1)     σ g ( D   circ )<1.39+0.011 d   p (nm).  (2)   
     
     
         12 . The dispersion of  claim 11 , wherein equation (1) is satisfied. 
     
     
         13 . The dispersion of  claim 11 , wherein equation (2) is satisfied. 
     
     
         14 . The dispersion of  claim 11 , wherein both equations (1) and (2) are satisfied. 
     
     
         15 . The dispersion of  claim 11 , wherein the geometric standard deviation of the aggregate particle diameters σ g (D circ ) satisfies the following equation:
   1.39+0.011 d   p (nm)>σ g ( D   circ )>1.3+0.011 d   p (nm).   
     
     
         16 . The dispersion of  claim 11 , wherein the dispersion has a solids concentration of about 5-50 wt. %. 
     
     
         17 . The dispersion of  claim 16 , wherein the dispersion has a solids concentration of about 15-40 wt. %. 
     
     
         18 . The dispersion of  claim 11 , wherein the dispersion comprises a stabilizer selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium hydroxide, triethylamine, and dimethylethanol amine. 
     
     
         19 . The dispersion of  claim 18 , wherein the dispersion has a pH of about 8-13. 
     
     
         20 . The dispersion of  claim 19 , wherein the dispersion has a pH of about 9-12.