Patent ID: 7019066

Claim:
A process for preparing a vulcanized rubber composition comprising: (a) a diene elastomer, (b) particles of an α-olefinic thermoplastic polymer having a melting point greater than or equal to 150° C., in an amount of 5 to 30 parts by weight per 100 parts diene elastomer (phr), wherein the mean size by weight of the particles is between 50 μm and 500 μm, (c) greater than 60 phr of reinforcing filler, and (d) from 3 to 8 phr of sulphur, the process comprising: (i) in a first thermomechanical working stage, kneading the elastomer, reinforcing filler and α-olefinic polymer in the powder state, such that the dropping temperature is approximately 155° C., (ii) in a second mechanical working stage, adding a sulphur vulcanization system to the mixture obtained on completion of stage (i), and (iii) in a third vulcanization stage, curing of the mixture obtained on completion of stage (ii), wherein the operating temperatures of stages (i)–(iii) are always below the melting temperature of the α-olefinic polymer, such that the polymer is dispersed in the elastomer in the form of substantially spherical particles.