Method for producing multilayer coatings

A basecoat composition comprising

• (i) an acrylate dispersion having a content of from 30 to 60% by weight of C1-C8-alkyl (meth)acrylate-containing monomers, from 30 to 60% by weight of vinylaromatic monomers and from 0.5 to 10% by weight of (meth)acrylic acid in the polymer, and
• (ii) a dispersion of a polymer which is obtained by subjecting an ethylenically unsaturated monomer or a mixture of ethylenically unsaturated monomers to free-radical polymerization in the presence of a water-insoluble initiator or a mixture of water-insoluble initiators and in an aqueous dispersion of a polyurethane resin which has a number-average molecular weight Mn of from 1000 to 30,000 daltons and comprises on average from 0.05 to 1.1 polymerizable double bonds per molecule, the weight ratio between the polyurethane resin and the ethylenically unsaturated monomer or the mixture of ethylenically unsaturated monomers is between 1:10 0 and 10:1, and
• (iii) a rheological assistant which comprises a synthetic polymer having ionic and or associative groups,
• wherein the proportion of component (i) is between 10 and 80% by weight, and the proportion of component (ii) is between 20 and 90% by weight, based in each case on the sum of the proportions by weight of components (i) and (ii), wherein, when used as a basecoat having a clearcoat applied thereover and a cured film formed therefrom, the clearcoat film demonstrates no delamination following condensation exposure according to DIN 5001KK and adbesion testing according to EN ISO 2409.

Process for producing a multicoat coating system on a substrate surface, comprising

• (A) applying to a substrate a first coating selected from the group consisting of surfacer coatings and aqueous water-based coating materials, to form a first coating film, followed by applying a basecoat composition to form a basecoat film, said basecoat comprising
• (i) a conventional acrylate dispersion laving a content of from 30 to 60% by weight of C1-C8-alkyl (meth)acrylate-containing monomers, from 30 to 60%/o by weight of vinylaromatic monomers and from 0.5 to 10% by weight of (meth)acrylic acid in the polymer, and
• (ii) a dispersion of a polymer which is obtained by subjecting an ethylenically unsaturated monomer or a mixture of ethylenically unsaturated monomers to free-radical polymerization in the presence of a water-insoluble initiator or a mixture of water-insoluble initiators and in an aqueous dispersion of a polyurethane resin which has a number-average molecular weight Mn of from 1000 to 30,000 daltons and comprises on average from 0.05 to 1.1 polymerizable double bonds per molecule, the weight ratio between the polyurethane resin and the ethylenically unsaturated monomer or the mixture of ethylenically unsaturated monomers is between 1:10 and 10:1, and
• (iii) a rheological assistant which comprises a synthetic polymer having ionic and/or associative groups,
• wherein the proportion of component (i) is between 10 and 80% by weight, and the proportion of component (ii) is between 20 and 90% by weight, based in each case on the sum of the proportions by weight of component (i) and (ii),
• (B) applying a suitable transparent topcoat composition to the resulting basecoat film, and
• (C) baking the basecoat film and the first coating film together with the topcoat film,
• wherein the baked topcoat film demonstrates no delamination following condensation exposure according to DIN 5001KK and adhesion testing according to EN ISO 2409.