Patent ID: 7666506

Claim:
A process for the preparation of a surface-modified nanoparticulate metal oxide, where the metal is chosen from the group consisting of aluminum, cerium, iron, titanium, zinc and zirconium, by a. precipitation of the metal oxide from an aqueous or alcoholic solution of one of its metal salts, b. separating off the precipitated metal oxide from the aqueous or alcoholic reaction mixture and c. subsequent drying of the metal oxide, wherein the precipitation of the metal oxide in process step a. takes place in the presence of a copolymer P which comprises, as monomers, A) 1 to 99 mol % of a N-vinylamide and B) 99 to 1 mol % of a monomer comprising, per molecule, one free-radically polymerizable α,β-ethylenically unsaturated double bond and one anionogenic and/or anionic group, with the proviso that the copolymer P must comprise no further monomers chosen from the group consisting of C 8 -C 30 -alkyl esters of monoethylenically unsaturated C 3 -C 8 -carboxylic acids, N-alkyl- or N,N-dialkyl-substituted amides of acrylic acid or of methacrylic acid with C 8 -C 18 -alkyl radicals, or vinyl esters of aliphatic C 8 -C 30 -carboxylic acids.