Patent ID: 8168736

Claim:
An emulsion polymer obtained by a process comprising polymerizing a mixture comprising a) from 5 to 99.9% by weight of one or more monomers having a solubility in water of <2% by weight at 20° C. and selected from the group consisting of monofunctional (meth)acrylate monomers, styrene and vinyl esters; b) from 0 to 70% by weight of one or more monomers copolymerized with the one or more monomers a); c) from 0 to 20% by weight of one or more doubly or multiply vinylically unsaturated compounds; d) from 0 to 20% by weight of one or more polar monomers having a solubility in water of >2% by weight at 20° C.; and e) 0.1-95% by weight of at least one activator, wherein the sum of a) to e) is 100% by weight of the polymerizable constituents of the mixture, e1) the activator is a compound of Formula I, wherein R 1 is hydrogen or methyl; X is a 2-hydroxypropylene group —CH 2 —CH(OH)—CH 2 —; R 2 is hydrogen or a linear or branched alkyl radical which has from 1 to 12 carbon atoms and is optionally monosubstituted or polysubstituted by hydroxyl groups or C 1 -C 4 -alkoxy groups, with the hydroxyl groups optionally partially esterified with (meth)acrylic acid; and R 3 , R 4 , R 5 , R 6 and R 7 are each, independently of one another, hydrogen or a linear or branched alkyl or alkoxy group which has from 1 to 8 carbon atoms and are optionally monosubstituted or polysubstituted by hydroxyl groups, where two of the radicals R 3 to R 7 may be joined to one another to form a five- to seven-membered ring and optionally form a fused aromatic ring system with the phenyl radical, and e2) the activator e) is covalently bound to the emulsion polymer.