polymers titanphosphate, processes for their manufacture and their use for the activation of metal surfaces before a zinkphosphatierung.

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.