Abstract: An aqueous dispersion, having a silicon dioxide powder having a silicon dioxide content of 10 to 60 wt.%, wherein the aqueous dispersion is stable in the pH range of 2 to 6, the aqueous dispersion additionally contains at least one compound, which is at least partially soluble in aqueous solution in the pH range 2 to 6 in the form of polyvalent cations, these being stable in a silicate-like environment as an anionic component of the particle surface of the silicon dioxide powder, the quantity of cation-providing compound in relation to the surface of the silicon dioxide is 0.001 to 0.1 mg cation-providing compound/m2 silicon dioxide surface, the cation-providing compound being calculated as the oxide, and the zeta potential of the aqueous dispersion has values of less than or equal to zero.
Type:
Grant
Filed:
August 21, 2003
Date of Patent:
May 20, 2008
Assignee:
Dequssa AG
Inventors:
Wolfgang Lortz, Christoph Batz-Sohn, Gabriele Perlet, Werner Will, Gerrit Schneider, Peter Neugebauer