| 摘要 |
A rubber composition comprises (a) as the major rubber constituent a rubbery homepolymer of butadiene-1,3 in which at least 80% of the units are joined cis 1,4 and which exhibits a 4-minute ML Mooney viscosity at 100 DEG C. in the range 35 to 120 and (b) from 1 to 25 parts per 100 of the homopolymer of a hydrocarbon oil having a viscosity-gravity constant from 0,79 to 1,0. Also present may be 0,5 to 10 parts of an organic acid, 0,5 to 15 parts of a rubber tackifying agent, 25 to 125 parts carbon black, 0,5 to 10 parts zinc oxide, 0,5 to 5 parts sulphur and 0,2 to 2,0 parts accelerator. Rosin and a condensate of formaldehyde with an alkylated phenol are specified tackifying agents, while preferred organic acids are those containing at least 10 carbon atoms per molecule. The preferred composition may be prepared by combining the homopolymer with hydrocarbon oil, masticating the mixture, adding 35-80 parts of a high structure carbon black having an oil absorption value of 49 to 76 litres/45 kg., and masticating the mixture at 66 DEG to 204 DEG C. The products may be vulcanized. |
