Patent ID: 7638574
Filing Date: 2009-12-29
Classification: B60C,C08F,C08K,C08L

Abstract:
1. A rubbery composition which is comprised of (1) an emulsion styrene-butadiene rubber, (2) carbon black, (3) core-shell particles, and (4) optionally, one or more additional rubbery polymers, wherein the core-shell particles are comprised of (a) a crosslinked elastomeric core consisting essentially of repeat units that are derived from at least one diolefin monomer and at least one crosslinking monomer selected from the group consisting of divinyl benzene, diisopropenylbenzene, and 1,2-polybutadiene, wherein the crosslinked elastomeric core has a glass transition temperature which is within the range of −20° C. to 20° C., and (b) a polymeric shell which is comprised of at least 75 weight percent repeat units that are derived from a vinyl aromatic monomer, wherein the polymeric shell has a glass transition temperature which is within the range of 50° C. to 160° C., wherein the emulsion styrene-butadiene rubber represents at least 50 weight percent of the total weight of the emulsion styrene-butadiene rubber and additional rubbery polymers in the rubbery composition, wherein the core-shell particles are present at a level which is within the range of 5 to 40 parts by weight based on the total weight of the emulsion styrene-butadiene rubber and additional rubbery polymers in the rubbery composition, and wherein the weight ratio of the core to the shell is within the range of 15:1 to 8:1.