Aqueous polymer latex

Abstract

The present invention relates to aqueous polymer latexes of film-forming copolymer particles obtainable by aqueous emulsion polymerisation of monoethylenically monomers M, which mainly comprise non-ionic monomers of the group consisting of alkyl(meth)acrylates, cycloalkyl(meth)acrylates and monovinylaromatic hydrocarbon monomers and which additionally comprise 0.01 to 1% by weight, based on the total weight of monomers M, of at least one monoethylenically unsaturated monomer M2 having a hydrolysable silane group; and 0.1 to 2% by weight, based on the total weight of monomers M, of at least one monoethylenically unsaturated monomer M3 having an acidic phosphate group, or a salt thereof and where the copolymer particles in the polymer latex have volume median particle diameter of at least 250 nm, as determined by dynamic light scattering according to the ISO 13321:1996 standard. The polymer latexes are particularly suitable as binders in coating compositions having high pigment volume concentration (PVC) of preferably above 60% and provide good wet scrub resistance and opacity to coatings obtained therefrom. The present invention also relates to a process for producing such polymer latexes, to waterborne coating compositions containing these latexes and to the use of said polymer latexes for improving the wet scrub resistance and the opacity of coating compositions having a pigment volume concentration (PVC) of preferably above 60%.