Short fiber-reinforced rubber composition and pneumatic radial tire using the same

Abstract

A short fiber-reinforced rubber composition comprises a master batch (A) comprised of (a) a first diene-based elastomer, (b) a polyolefin having a melting point of 100-150° C. and (c) short fibers of a thermoplastic polymer having amide group in its main chain, and a second diene-based elastomer (B) kneaded with the master batch (A), in which an amount of the component (c) is 5-30 parts by weight based on 100 parts by weight in total of the first diene-based elastomer and the second diene-based elastomer. Further, a rubber sheet made of the short fiber-reinforced rubber composition is inserted in a given zone of the sidewall portion, whereby the stiffness of the sidewall portion is enhanced to simultaneously establish the steering stability and the ride comfort and reduce the rolling resistance.

Dependencies are inferred from the claim text.