Aqueous coating composition and production of topcoat layers by using the coating composition

The invention relates to an aqueous coating composition, containing at least one first polymer (A) as a binder, at least one cross-linking agent (B), and at least one copolymer (C) as a second binder, which at least one copolymer can be obtained by copolymerizing ethylenically unsaturated monomers in the presence of a polymerizable polyurethane resin having carbon double bonds, wherein the weight ratio of polymer (A) to polymer (C) is greater than 3.0. The invention further relates to a method for producing a topcoat layer on a metal substrate, comprising applying the coating composition according to the invention to and curing said coating composition on a metal substrate, and a metal substrate that has been coated according to the method according to the invention. 本发明涉及水性涂料组合物，其包含：至少种第聚合物(A)作为基料、至少种交联剂(B)和至少种共聚物(C)作为第二基料，所述共聚物(C)可通过烯属不饱和单体在具有可聚合碳双键的聚氨酯树脂存在下共聚而得到，聚合物(A)与聚合物(C)的重量比为大于3.0。本发明进步涉及在金属基底上制备顶涂层的方法，其包括将本发明涂料组合物施涂于金属基底上，随后固化，以及通过本发明方法涂覆的金属基底。