Patent ID: 7834076

Claim:
A dispersion containing aluminium oxide of pyrogenic origin and water, wherein the aluminium oxide is present in the form of aggregated primary particles with a BET surface area of 20 to 200 m 2 /g and has a mean, volume-based aggregate diameter in the dispersion of less than 100 nm, is surface-modified with (i) organophosphonic acids or salts thereof, where the surface is completely or partially modified, the organophosphonic acids bear at least one amino and/or hydroxy group and is present in an amount ranging from 0.2 to 7.5 μmol/m 2 surface area of the aluminium oxide and (ii) at least one hydroxycarboxylic acids or salts thereof present in an amount ranging from 0.1 to 5.5 μmol/m 2 surface area of the aluminium oxide; the aluminium oxide is present in an amount ranging from 20 to 70 wt. %, based on the total weight of the dispersion.