The present invention relates to an aqueous polymer emulsion comprising at least 30 wt. % of a vinyl copolymer (A), said vinyl copolymer comprising: (I) from 10 to 90 wt. % of 2-octyl acrylate monomer; (II) from 10 to 90 wt. % of at least one itaconate ester monomer according to formula (1) in which A and B may be different or the same and A and B are independently an alkyl group or an aryl group; and (III) from 0 to 80 wt. % of ethylenically unsaturated monomer other than (I) and (II); whereby the summed amount of (I), (II) and (III) is 100 wt. % and whereby the amount of vinyl copolymer (A) is given relative to the total weight amount of the polymers present in the emulsion.