Patent ID: 8623972

Claim:
A process for preparing a styrene-butadiene copolymer, comprising the steps of: polymerizing, via aqueous emulsion polymerization, styrene-butadiene copolymer reactants, said reactants comprising styrene monomer, butadiene monomer, and a chain transfer agent, wherein said polymerizing is performed at a temperature between 40° C. and 65° C. and a Mooney viscosity of between 85 and 150, and in the presence of a resinous soap emulsifier, whereby forming a styrene-butadiene copolymer latex wherein the total solids content thereof is maintained in the range of 20-40% where the polymerization is terminated after 60%-80% conversion of the starting reactants via the addition of a reaction terminator; and wherein said resinous soap emulsifier being incorporated into the styrene-butadiene copolymer in its acid form, and further wherein said styrene-butadiene copolymer has a styrene content of between 45 and 75%.