The invention relates to a method for producing chromophore and/or effect
giving multilayer lacquers according to the wet-on-wet method. A water
base lacquer is applied which contains at least one graft copolymer
containing (A) at least one (meth)acrylate copolymer and (B) at least one
polyurethane. The graft copolymer can be produced by (1) dispersing at
least one hydrophilic or hydrophobic self cross-linking polyurethane (B)
with a statistical average of at least one terminal and/or at least one
lateral olefinically unsaturated group and at least one blocked
isocyanate group per molecule in an aqueous medium. (2) A mixture of a at
least one monomer (a1) with at least one isocyanate reactive functional
group at last one monomer (a2) that can be copolymerised therewith is
subsequently radically copolymerised in an emulsion in the presence of
the polyurethane (B) or the polyurethanes (B). A powder slurry
transparent lacquer layer is added to the resulting base lacquer layer.
The base lacquer layer and the transparent lacquer layer are hardened
together. The invention also relates to novel hydrophilic or hydrophobic
self cross-linking polyurethanes (B) with at least one lateral and/or at
least one terminal olefinically unsaturated group and at least one
lateral blocked isocyanate group per molecule and graft copolymers on the
basis of said polyurethanes (B) as well as the use thereof.