Finely particulate plastics dispersions prepared by metering a mixture containing four monomers into an aqueous liquor containing an anionic emulsifier

Claim 1

A process for the preparation of finely particulate plastics dispersions particularly suitable for the solidifying primer coating of substrates to be painted, which comprises metering a monomer mixture containing I. from 20 to 80% by weight of monomer selected from styrene, methylmethacrylate and mixtures thereof as hardening component, provided that methyl methacrylate, if present, does not exceed 15% by weight of said mixture, II. from 20 to 80% by weight of monomer selected from acrylic acid and methacrylic acid esters of linear and branched alcohols having from 2 to 8 carbon atoms and mixtures thereof as plasticizing component, III. from 0.1 to 5% of an amide of an α,β-unsaturated carboxylic acid, and IV. from 0.1 to 5% of an α,β-unsaturated monocarboxylic acid, in the form of the pure monomer mixture or a preliminary emulsion, simultaneously with an initiator, into an aqueous liquor containing from 0.5 to 10% by weight of an anionic emulsifier, said monomers being used in such an amount that the solids content of the final dispersion does not exceed 45% by weight, polymerizing said monomers in said aqueous liquor to form said dispersion, and adjusting said dispersion to a pH of 7 to 10.