AQUEOUS DISPERSION OF AT LEAST TWO POLYMERIC RESINS AND AQUEOUS COATING COMPOSITION COMPRISING SAME FOR APPLYING A TOPCOAT

摘要

The present invention relates to an aqueous dispersion (P) of at least two polymeric resins (P1) and (P2) which are different from one another, (P1) being a copolymer obtainable by copolymerizing ethylenically unsaturated monomers in the presence of at least one polyurethane resin having polymerizable carbon double bonds, and (P2) being a polyester having functional hydroxyl groups, which has an acid number of <25 mg of KOH per g of polyester, and (P) being obtainable by a process encompassing at least four steps (1), (2), (3), and (4), to an aqueous coating composition comprising the aqueous dispersion (P), to a process for at least partly coating at least one substrate metal surface, coated with at least one primer coat, with a topcoat, using the aqueous coating composition, and to an at least partly coated substrate obtainable by such a process.

主权项

1. An aqueous dispersion (P), comprising:
a polymeric resin (P1), and a polymeric resin (P2) which is different from the polymeric resin (P1), wherein the polymeric resin (P1) is a copolymer obtained by a copolymerization of ethylenically unsaturated monomers in the presence of at least one polyurethane resin comprising polymerizable carbon double bonds, and the polymeric resin (P2) is a polyester comprising functional hydroxyl groups and which has an acid number of <25 mg of KOH per g of polyester, and wherein the aqueous dispersion (P) is obtained by a process comprising: (1) preparing a dispersion or a solution comprising the polymeric resin (P1) in at least one organic solvent, (2) preparing a mixture of the dispersion or the solution comprising the polymeric resin (P1) and a melt or a solution comprising the polymeric resin (P2), (3) adding water to the mixture, and (4) removing the organic solvent from the mixture, to obtain the aqueous dispersion (P).