A process for producing an aqueous polymer dispersion by free-radically initiated aqueous emulsion polymerization of ethylenically unsaturated monomers in the presence of at least one dispersant and at least one polymerization initiator, comprising the following steps: i)provision of an aqueous polymer dispersion S formed essentially from uncharged, monoethylenically unsaturated monomers M0 having a low water solubility of less than 100 g/l at 20°C and 1 bar; ii) free-radical emulsion polymerization of a monomer composition M1 in the presence of a dispersant composition D1 and the aqueous polymer dispersion S, said monomer composition M1 comprising: • 90% to 99.9% by weight, based on the total amount of monomers in the monomer composition M1, of at least one uncharged monoethylenically unsaturated monomer MA1 having a water solubility of less than 100 g/L at 20°C and 1 bar; and • 0.1% to 10% by weight, based on the total amount of monomers in the monomer composition M1, of at least one anionic or uncharged monoethylenically unsaturated monomer MB1 having a water solubility of at least 200 g/L at 20°C and 1 bar; and then iii) free-radical emulsion polymerization of a monomer composition M2 in the presence of a dispersant composition D2 in the aqueous polymer dispersion obtained in step ii), said monomer composition M2 comprising: • 90% to 99.9% by weight, based on the total amount of monomers in the monomer composition M2, of at least one uncharged monoethylenically unsaturated monomer MA2 having a water solubility of less than 100 g/L at 20°C and 1 bar; and • 0.1% to 10% by weight, based on the total amount of monomers in the monomer composition M2, of at least one anionic or uncharged monoethylenically unsaturated monomer MB2 having a water solubility of at least 200 g/L at 20°C and 1 bar; wherein the dispersant composition D1 comprises at least one first anionic dispersant D1a having at least one sulfate or sulfonate group, and optionally at least one second dispersant D1b having at least one phosphate or phosphonate group; wherein the dispersant composition D2 comprises at least one dispersant D2b having at least one phosphate or phosphonate group; wherein the weight ratio of the amount of dispersant D1b used in stage 1 to the amount of dispersant D2b used in stage 2 is less than 1. i)provision of an aqueous polymer dispersion S formed essentially from uncharged, monoethylenically unsaturated monomers M0 having a low water solubility of less than 100 g/l at 20°C and 1 bar; ii) free-radical emulsion polymerization of a monomer composition M1 in the presence of a dispersant composition D1 and the aqueous polymer dispersion S, said monomer composition M1 comprising: • 90% to 99.9% by weight, based on the total amount of monomers in the monomer composition M1, of at least one uncharged monoethylenically unsaturated monomer MA1 having a water solubility of less than 100 g/L at 20°C and 1 bar; and • 0.1% to 10% by weight, based on the total amount of monomers in the monomer composition M1, of at least one anionic or uncharged monoethylenically unsaturated monomer MB1 having a water solubility of at least 200 g/L at 20°C and 1 bar; and then • 90% to 99.9% by weight, based on the total amount of monomers in the monomer composition M1, of at least one uncharged monoethylenically unsaturated monomer MA1 having a water solubility of less than 100 g/L at 20°C and 1 bar; and • 0.1% to 10% by weight, based on the total amount of monomers in the monomer composition M1, of at least one anionic or uncharged monoethylenically unsaturated monomer MB1 having a water solubility of at least 200 g/L at 20°C and 1 bar; iii) free-radical emulsion polymerization of a monomer composition M2 in the presence of a dispersant composition D2 in the aqueous polymer dispersion obtained in step ii), said monomer composition M2 comprising: • 90% to 99.9% by weight, based on the total amount of monomers in the monomer composition M2, of at least one uncharged monoethylenically unsaturated monomer MA2 having a water solubility of less than 100 g/L at 20°C and 1 bar; and • 0.1% to 10% by weight, based on the total amount of monomers in the monomer composition M2, of at least one anionic or uncharged monoethylenically unsaturated monomer MB2 having a water solubility of at least 200 g/L at 20°C and 1 bar; • 90% to 99.9% by weight, based on the total amount of monomers in the monomer composition M2, of at least one uncharged monoethylenically unsaturated monomer MA2 having a water solubility of less than 100 g/L at 20°C and 1 bar; and • 0.1% to 10% by weight, based on the total amount of monomers in the monomer composition M2, of at least one anionic or uncharged monoethylenically unsaturated monomer MB2 having a water solubility of at least 200 g/L at 20°C and 1 bar;