Vehicle tyre having a tread comprising a heat-expandable rubber composition

Abstract

A vehicle tyre, usable in winter weather, includes a tread formed of a rubber composition that is heat-expandable when in an unvulcanized state, and expanded when in a vulcanized state. When unvulcanized, the composition includes a diene elastomer, such as natural rubber and/or a polybutadiene; more than 50 phr of a reinforcing filler, such as silica and/or carbon black; between 5 and 25 phr of a sodium- or potassium-including carbonate or hydrogen carbonate; and between 2 and 20 phr of a carboxylic acid having a melting point between 60° C. and 220° C., such as citric acid or stearic acid. A total content of the carboxylic acid and the carbonate or the hydrogen carbonate is greater than 10 phr. Presence of the carboxylic acid and the carbonate or the hydrogen carbonate makes it possible to greatly improve the tyre's grip on melting ice.

Dependencies are inferred from the claim text.