Coatings having improved resistance to stains and dirt

摘要

The invention relates to aqueous coating compositions based on an aqueous polymer dispersion as binder, having high performance levels of resistance to stains and dirt without specialist functional monomers. Said aqueous polymer dispersion having an MFFT between 0 and 50° C. comprises polymer particles obtained by emulsion polymerization in at least two steps with at least two polymer phases P1 and P2, P1 representing from 75 to 90% by weight of P1+P2 having a Fox Tg1 from 0 to 40° C. and P2 having a Fox Tg2 from 0 to 40° C., said polymer P2 representing from 10 to 25% by weight of the sum of polymers P1 and P2 and having a calculated Hansch parameter 2.0 and at least one ethylenically unsaturated monomer bearing an acetoacetoxy and/or amine or ureido functional group, said acetoacetoxy and/or amine or ureido functional group being borne by the external surface of P2 phase.