Patent ID: 8053542
Filing Date: 2011-11-08
Classification: C08C,C08F,C08L

Abstract:
1. A process for polymerizing a polymer comprising monomeric units derived from styrene and 1,3-butadiene, said process comprising: A) adding less than 60 weight percent of the total amount of the butadiene used in the polymerization, to a reactor comprising the total amount of styrene used in the polymerization, and solvent; B) adding at least one initiator to the reactor, and allowing the reaction to proceed for a time t; C) adding the remaining amount of butadiene to the reactor in two or more separate additions; and wherein for each butadiene addition, the amount of subsequent butadiene added, is less than, or equal to, the amount of butadiene added in the immediately prior addition; and wherein for each butadiene addition, the butadiene is added over a time, t