Patent ID: 7282547

Claim:
A process for preparing an aqueous styrene-butadiene polymer dispersion, comprising: polymerizing, in an aqueous emulsion containing a free radical initiator, by a monomer feed technique, in a polymerization vessel a monomer mixture comprising from 40 to 80% by weight of styrene as monomer M1, from 20 to 60% by weight of butadiene as monomer M2, and from 0 to 40% by weight, based on 100% by weight of monomers, of ethylenically unsaturated comonomers M3 other than styrene and butadiene, the emulsion also containing from 0.05 to 0.5% by weight, based on 100% by weight of monomers, of at least one hydrocarbon compound selected from the group consisting of compounds having from 6 to 20 carbon atoms, which upon abstraction of a hydrogen atom form a pentadienyl or 1-phenylallyl radical, and α-methylstyrene dimer, said monomer mixture being supplied to the polymerization reaction medium over the course of and within a period of 3 hours.