Aqueous primary dispersions and coating materials comprising dispersed and/or emulsified, solid and/or liquid polymer particles and/or dispersed solid core-shell particles having a diameter500 nm, preparable by free-radical microemulsion or miniemulsion polymerization of at least one olefinically unsaturated monomer (A) in the presence of at least one hydrophobic crosslinking agent for the (co)polymer resulting from the monomer or monomers (A), wherein said monomer or monomers (A) is or are dispersed prior to (co)polymerization in an aqueous dispersion of said crosslinking agent or agents; processes for preparing them, and their use.