ELECTRODEPOSITION COATINGS FOR USE OVER ALUMINUM SUBSTRATES

摘要

The present invention relates to an aqueous dispersion comprising - a base-neutralized resinous composition containing an ungelled phosphated epoxy resin (a) in which the phosphated epoxy resin comprises a mixture of the reaction product of one or more polymeric epoxy compounds with phosphoric acid and with an organophosphonic acid and/or an organophosphinic acid; - a curing agent (b), whereby (a) the phosphated epoxy resin is present in amounts of 50 to 90 percent by weight and (b) the curing agent is present in amounts of 10 to 50 percent by weight, the percentages being based on total solids weight of (a) and (b); and - an azole and to the use of the aqueous dispersion in a process for providing a coating on an aluminum substrate by passing electric current between the substrate acting as an anode and a cathode in electrical contact with an electrodeposition bath containing said aqueous dispersion.