COATING AGENT BASED ON A HYDROXYL GROUP-CONTAINING POLYACRYLATE RESIN AND ITS USE IN PROCESSES FOR PRODUCING A MULTICOAT PAINT SYSTEM

摘要

The present invention concerns a coating agent comprising: (A) at least one hydroxyl group-containing polyacrylate resin; (B) at least one isocyanate cross-linking agent; and optionally (C) at least one hydroxyl group-containing polyester-modified polyacrylate resin. The invention is characterized in that the polyacrylate resin (A) can be obtained by polymerizing: (a1) at least one substantially carboxyl group-free (meth)acrylic acid ester; (a2) at least one copolymerizable hydroxyl group-containing monomer which is different from (a3); (a3) at least one reaction product comprising acrylic acid and/or methacrylic acid with the glycidyl ester of a monocarboxylic acid branched in the alpha position and with 5 to 18 carbon atoms per molecule; (a4) optionally a monomer containing at least one carboxyl group; (a5) at least one polysiloxane macromonomer with a number average molecular weight of between 1,000 and 40,000 and on average between 0.5 and 2.5 ethylenically unsaturated double bonds per molecule or with on average between 0.5 and 2.5 epoxide groups per molecule; (a6) at least one vinyl aromatic compound; and (a7) optionally at least one further, substantially carboxyl group-free monomer. The monomers are selected in terms of type and amount such that the polyacrylate resin (A) has the desired OH number and acid number, the amount of (a5) being less than 5 wt.%.