AQUEOUS POLYMER LATEX

The present invention relates to aqueous polymer latexes of film-forming copolymers obtainable by aqueous emulsion polymerisation of monomers M, which comprise at least 80% by weight, based on the monomers M, of-at least one non-ionic monomer M1, which is selected from C1-C20-alkyl esters of acrylic acid, C5-C20-cycloalkyl esters of acrylic acid, C1-C20-alkyl esters of methacrylic acid, C5-C20-cycloalkyl esters of methacrylic acid and monovinyl aromatic monomers; -one or more monoethylenically unsaturated monomers M2, which are selected from monoethylenically unsaturated monocarboxylic acids having 3 to 6 carbon atoms and monoethylenically unsaturated dicarboxylic acids having 4 to 6 carbon atoms; and where the polymer latex contains an emulsifier combination comprising i. at least one first emulsifier (1), which is selected from salts, in particular from the alkali metal salts and the ammonium salts of sulfated ethoxylated C8-C20-alkanols having a degree of ethoxylation in the range from 5 to 20 and sulfated ethoxylated tristyrylphenols having a degree of ethoxylation in the range from 5 to 20, and ii. at least one second emulsifier (2), which is selected from the salts, in particular from the alkali metal salts and the ammonium salts of a sulfated ethoxylated C8-C20-alkanol having a degree of ethoxylation in the range from 21 to 50 and sulfated ethoxylated tristyrylphenols having a degree of ethoxylation in the range from 21 to 50. The present invention also relates to a process for producing such polymer latexes and to the use of these polymer latexes as binders in waterborne coating compositions which contain at least one inorganic tannin blocking compound and to the use of such coating compositions for coating tannin-containing substrates such as wood or woodbased materials.