| abstract |
One method of producing a multilayer coating uses an aqueous clear coating composition containing a polyacrylic resin as a binder. The polyacrylic resin is obtained by adding, successively or alternately in partial amounts, to an organic solvent, a mixture composed of an ethylenically unsaturated monomer (a1) containing carboxyl groups and a monomer (22) free of carboxyl groups and a mixture ( b) composed of (meth)acrylates free of carboxyl groups, of ethylenically unsaturated monomers containing hydroxyl groups and optionally other ethylenically unsaturated monomers, then by polymerizing the mixture obtained in the presence of an initiator forming a radical, and, when the polymerization is completed, by neutralizing the polyacrylic resin obtained which is then dispersed in water. The nature and quantity of (a1), (a2) and 9b) are chosen so that the polyacrylic resin has a hydroxyl index of 40 to 200, an acidity index of 20 to 100 and a glass transition temperature (TG) from -40 to +60°C. |