AQUEOUS POLYMER LATEX OF FILM-FORMING COPOLYMERS SUITABLE AS BINDER IN WATERBORNE COATING COMPOSITIONS

The present invention relates to aqueous polymer latexes of film-forming copolymers which are suitable as binders in waterborne coating compositions, and are obtainable by aqueous emulsion polymerisation of ethylenically unsaturated monomers M, which comprise *20 to 95% by weight, based on the total amount of monomers M, of at least one monomer M1, which is selected from isobutyl acrylate and isoamyl acrylate and mixtures thereof; *0 to 55% by weight, based on the total amount of monomers M, of at least one monomer M2, which is selected from ethyl acrylate, n-propyl acrylate, n-butyl acrylate, n-pentyl acrylate, C6-C20-alkyl esters of acrylic acid and C5-C20-alkyl esters of methacrylic acid and mixtures thereof; *5 to 50% by weight, based on the total amount of monomers M, of at least one monomer M3, which is selected from tert-butyl acrylate, C1-C4-alkyl esters of methacrylic acid, C5-C20-cycloalkyl esters of acrylic acid, C5-C20-cycloalkyl esters of methacrylic acid, C5-C20-cycloalkylmethyl esters of acrylic acid, C5-C20-cycloalkylmethyl esters of methacrylic acid, where cycloalkyl in the aforementioned monomers is mono-, bi- or tricyclic and where 1 or 2 CH2 moieties of cycloalkyl may be replaced by O and where cycloalkyl may be unsubstituted or carry 1, 2, 3 or 4 methyl groups, and monovinyl aromatic monomers and mixtures thereof; *0.05 to 4% by weight, based on the total amount of monomers M, of least one monomer M4, which is selected from monoethylenically unsaturated monomers having an acidic group; where the total amount of monomers M1 and M2 is in the range from 45 to 95% by weight, in particular 50 to 90% by weight, especially 55 to 85% by weight based on the total amount of ethylenically unsaturated monomers M, and where the total amount of monomers M1, M2 and M3 is at least 90% by weight, in particular at least 95% by weight, based on the total amount of ethylenically unsaturated monomers M.