POLYMERS TITANIUM PHOSPHATES, METHOD FOR THE PRODUCTION THEREOF AND THEIR USE FOR ACTIVATING METAL SURFACES BEFORE ZINC PHOSPHATION

摘要

The polymer titanium(IV) phosphates are obtainable by reaction of titanium(IV) compounds with alkali metal phosphates. These polymer titanium(IV) phosphates are characterised in that at least 95% by weight of the polymer particles have particle diameters of less than 200 nm. The small particle diameter is achieved by adding a titanium(IV) complexing agent predominantly before or during the reaction in less than a stoichiometric amount, relative to the titanium(IV) content, to the aqueous reaction mixture comprising titanium(IV) compound, alkali metal phosphate and water. Preferably, poly(aldehydocarboxylic acids) and/or 1,1-diphosphonic acids or alkali metal salts thereof are used as complexing agents.