To obtain a hydrocarbon resin and a rubber composition compounded with the resin suitable for the purpose in view of the fact that rubber compositions having mild crosslinking rate while having postcure mechanical strength and durability are demanded.
The hydrocarbon resin is obtained by thermal copolymerization between (a) vinylcyclohexene or tetrahydroindene, (b1) cyclopentadiene or dicyclopentadiene and (b2) an ethylidenenorbornene, and (c) a cracked oil fraction 20-220°C in boiling point ( except the component(b1) ). The rubber composition is obtained by compounding the hydrocarbon resin. This rubber composition enables the scorch time of tires to be extended while retaining their cutting resistance and chipping resistance at levels equivalent to the case with the conventional technology, therefore facilitating tire manufacturing process control.
KAWAI KAZUO