Rubber composition and process for producing thereof

摘要

A process for producing a rubber composition comprising (i) a total amount of 100 parts by weight of starting rubbers (A) and (B), including 30 to 90 parts by weight of the starting rubber (A) having a glass transition temperature (Tg) of -40 DEG to 10 DEG C. and 10 to 40 parts by weight of the starting rubber (B) which is viscoelastically incompatible with the starting rubber (A) and has a Tg of at least 20 DEG C. lower than the Tg of the starting rubber (A) and (ii) 60 to 100 parts by weight of a reinforcing agent, wherein the starting rubber (A) and at least 80% by weight of the total weight of the reinforcing agent are mixed in a hermetic type mixer at 130 DEG C. to 200 DEG C. for at least 10 seconds, then the starting rubber (B) and the remaining reinforcing agent are added and mixed.