Patent ID: 6153695
Filing Date: 2000-11-28
Classification: C08F,C08L

Abstract:
A polymerization process comprising:polymerizing styrene monomer in the presence of a lithium catalyst starting at a temperature of 50 to 55 degrees centigrade and ending at a temperature of 60 to 65 degrees centigrade in the presence of a solvent for a sufficient period of time to convert substantially all of the styrene to form styrene polymer chains terminated by a lithium atom;adding a conjugated butadiene in the presence of a solvent;continuing the polymerization process at a temperature from 60 to 90 degrees centigrade, wherein the polymerization temperature after the butadiene addition is higher than the polymerization temperature for styrene; andadding a coupling agent having from 3 to 7 epoxy groups per molecule at a temperature not greater than 50 degrees centigrade.