| abstract |
The present invention relates to a rubber composition improving the trade-off between the baking rigidity and the hysteresis of the composition. Said composition contains: 0 to less than 20 phr of butyl rubber; more than 50 to 100 phr of a polyisoprene matrix, the polyisoprene matrix containing an epoxidized polyisoprene having an epoxidation molar ratio of 5% to less than 0%; a carbon black and a silica, the carbon black weight being greater than 50% of the total weight of carbon black and silica; 0 to less than 2 phr of a coupling agent; and a crosslinking system. The epoxidized polyisoprene is a natural epoxidized rubber, a synthetic epoxidized polyisoprene having a cis-1,4 bond molar ratio of at least 90% before epoxidation, or the mixture thereof, with the proviso that, if the epoxidized polyisoprene is an epoxidized polyisoprene having an epoxidation molar ratio of 5% to 25%, the rubber composition contains more than 50 phr of epoxidized polyisoprene. |