Aqueous coating agent, process for its preparation, and its use for coating cans, based on acrylic monomers, epoxy-polyesters and methylol functional curing agents

摘要

The invention relates to an aqueous coating agent, obtained from an epoxy resin, ethylenically unsaturated monomers, some of which contain carboxyl groups, a peroxide initiator in a proportion of at least 2% by weight, relative to the total weight of the monomers, a crosslinking agent, a neutralizing agent, organic solvents, and, if appropriate, further conventional additives, such as plasticizers, stabilizers, wetting agents, dispersion auxiliaries, catalysts and pigments. The coating agent is based on a binder a) which is obtainable fromP PA) 20 to 80% by weight of an epoxy resin having an average of more than one epoxy group per molecule and having an average molecular weight of at least 500,PPB) 1 to 60% by weight of polyester polycarboxylic acids having an average molecular weight of 500 to 5,000 and having an acid number of 30 to 150, andPP C) 10 to 50% by weight of ethylenically unsaturated monomers, 10 to 50% by weight of the monomers containing carboxyl groups,PP where the sum of A), B) and C) is 100% by weight, the binder a) has an acid number of 20 to 150, and the crosslinking agents b) used are phenolic and/or amino resins, with the proviso that the coating agent contains PPa) 30 to 70% by weight of the binder a), PPb) 2 to 30% by weight, preferably 5 to 16% by weight, of the crosslinking agent b),PPc) 1 to 7% by weight, preferably 2 to 5% by weight, of ammonia and/or amine as neutralizing agent, andP Pd) 20 to 60% by weight of organic solvents, PPwhere the sum of a), b), c) and d) is 100% by weight. The present invention also relates to a process for the preparation of the coating agents, and the use thereof for coating of cans.