PURPOSE: To provide the titled composition having low rolling resistance and heat-generation, and high breakage strength, by compounding a rubber composed mainly of an isoprene-butadiene random copolymer containing cis-1,4-bond with carbon black and a vulcanizing agent.
CONSTITUTION: An isoprene-butadiene random copolymer containing ≥90% cis-1,4 bond, or a mixture of said copolymer and one or more other diene rubbers is used as a stock rubber, and is compounded with carbon black and a vulcanizing agent. The isoprene-butadiene random copolymer is the one having an isoprene-content of 40W95(wt)%, and its amount in the stock rubber is ≥20%. The other diene rubber is natural rubber, polyisoprene rubber or polybutadiene rubber (having a cis-bond content of ≥90%) and its amount in the stock rubber is ≥20%.
EGASHIRA YOSHINORI
HASHIMOTO TAKATSUGU
| JPS58125714A | 1983-07-26 |