Process for the preparation of large-particle, aqueous plastic dispersions

A process for the preparation of a large-particle, aqueous plastic dispersion by emulsion polymerization of monomers which are polymerizable by free radicals, in an aqueous phase as dispersion medium, comprising the step of polymerizing said monomers in the presence of

• an anionic emulsifier;
• an nonionic, water-soluble polymer auxiliary;
• a polymerization initiator forming free radicals;
• water-soluble salt;
• and
• conventional polymerization auxiliaries, wherein the polymer auxiliary is added before polymerization, wherein the water-soluble salt is at least one member selected from the group consisting of alkali metal salt and ammonium salt and is present at the start of the polymerization in an amount of 1 to 250 mmol of alkali metal ions or ammonium ions which are not bonded to emulsifier in the aqueous phase per liter of aqueous phase, wherein the polymer auxiliary is a polyethylene oxide block-containing polymer having an AB block structure, in which A is either a branched or non-branched hydrophobic alkyl or (alkyl)aryl radical comprising 15 to 70 C atoms or oleyl or distyrylphenyl radical, and B is a non-branched hydrophilic radical comprising at least 50 ethylene oxide units, and wherein the amount of the polymer auxiliary, based on 100 parts by weight of the monomer, is 0.0001 to 0.05 parts by weight, wherein the polymerization is carried out by batch procedure or is started in a batch procedure and, after particle formation phase, is continued and completed under conditions for graft polymerization preventing the formation of new particles.