Patent ID: 7034081

Claim:
Branched and coupled polymers based on conjugated dienes or on conjugated dienes and vinylaromatic compounds and on polyfunctional, organic compounds having at least 4 groups which are capable of coupling, wherein the polymers have a molecular weight ratio (M. w /M n ) of 1.0 to 3.0, a weight-average molecular weight (M w ) of 400,000 to 2,000,000, a glass transition temperature (T G ) of −50 to −10° C., an amount of 1,2-vinyl groups of 40 to 80%, based on the diene units present in the polymer, and a degree of coupling of at least 45%, at least 60% of the coupled polymers having a degree of branching of greater than two, with the proviso that the amount by weight of polymers with 4- and more than 4-fold branching, based on 100 g of polymer, is greater than the amount by weight of polymers with 3-fold branching, and wherein the difference in the solution viscosity of the polymers before and after the coupling is in the range from 100 to 400 (measured with a solution of 0.5 g polymer in 100 ml toluene, determined at 25° C. with an Ubbelohde viscometer).