Abstract: The present invention relates to a polymer latex obtained by aqueous emulsion polymerization of a mixture of ethylenically unsaturated monomers comprising a) vinyl aromatic compounds; b) conjugated dienes; c) hydroxyalkyl esters of ethylenically unsaturated acids in an amount of 2 to 10 wt.-% based on the total weight of monomers; and d) ethylenically unsaturated carboxylic acids or salts thereof in an amount of 0 to 0.15 wt.-% based on the total weight of monomers; wherein the weight ratio of vinyl aromatic compounds to conjugated dienes is at least 1.3:1 and the polymer latex comprises 2 to 10 wt.-% based on total weight of monomers of non-ionic surfactants having an HLB of 17 to 19 and to constructions materials, preferably cementitious compositions comprising same.

Abstract: The present invention provides a core shell polymer comprising (i) a core comprising a polymer having a Tg in the range of from ?15 to 35° C., which polymer is formed from a monomer mixture comprising at least one conjugated diene monomer and (ii) a shell comprising a polymer having a Tg in the range of from 40 to 180 ° C., which polymer is formed from a monomer mixture comprising at least one aromatic vinyl monomer, wherein the gel content of the core polymer is below 62%.