Patent ID: 7375148
Filing Date: 2008-05-20
Classification: C08F

Abstract:
1. A process for preparing an aqueous styrene-butadiene polymer dispersion by free-radical aqueous emulsion polymerization of a monomer mixture comprising styrene, butadiene, and optionally up to 30% by weight, based on 100% by weight of monomers, of ethylenically unsaturated comonomers other than styrene and butadiene; said process comprising: polymerizing the monomer mixture in a polymerization vessel by a monomer feed technique in the presence of a regulator system comprising, based on 100% by weight of monomers, from 0.02 to 0.5% by weight of at least one hydrocarbon having from 6 to 20 carbon atoms, selected from compounds which on abstraction of a hydrogen atom form a pentadienyl radical or 1-phenylallyl radical, and from 0.3 to 2% by weight of an organic compound containing at least one SH group wherein at least 30% of the hydrocarbon is included in the initial charge to the polymerization vessel; and wherein at least 90% of the total monomer mixture is metered into the polymerization reaction under polymerization conditions.