RUBBER COMPOSITION FOR RUN-FLAT TIRE

摘要

The present invention provides a rubber composition for a run-flat tire which improves the ride comfort and steering stability during normal travel over the conventional level while reducing rolling resistance when a tire is produced by adding carbon black having controlled colloidal properties. A rubber composition for a run-flat tire comprises from 20 to 100 parts by weight of a reinforcing filler per 100 parts by weight of a diene rubber containing from 10 to 80 wt.% of butadiene rubber and from 10 to 40 wt.% of natural rubber; wherein the reinforcing filler contains at least 50 wt.% of carbon black; a mode diameter Dst in a mass distribution curve of a Stokes diameter of aggregates of the carbon black is at least 145 nm; a nitrogen adsorption specific surface area N 2 SA is from 45 to 70 m 2 /g; and a ratio N 2 SA/IA of the nitrogen adsorption specific surface area N 2 SA to an iodine adsorption IA (units: mg/g) is from 1.00 to 1.40.