Copolymer rubber composition with silica filler, tires having a base of said composition and method of preparing same

  • US 5,227,425 A
  • Filed: 02/20/1992
  • Issued: 07/13/1993
  • Est. Priority Date: 02/25/1991
  • Status: Expired due to Term
First Claim
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1. A sulfur-vulcanizable rubber composition formed by a process comprising the steps of(a) preparing a base from a copolymer of a conjugated diene and an aromatic vinyl compound prepared by solution polymerization in a hydrocarbon solvent having a total content of aromatic vinyl compound of between 5% and 50% and a glass transition temperature (Tg) of between 0°

  • C. and -80°

    C., and(b) thermomechanically working the base with a filler, the majority portion of which is a silica having a BET surface area of between 100 and 250 m2 /g, a CTAB surface area of between 100 and 250 m2 /g, an oil absorption measured in DBP of between 150 and 250 ml/100 g, and an average projected area of the aggregates greater than 8500 nm2 before working and between 7000 and 8400 nm2 after working, wherein the silica is added in an amount of from 30 to 150 parts by weight per 100 parts by weight of copolymer, together with other additives conventionally employed with the exception of the vulcanization system, said thermomechanical working including at least one thermal step reaching a maximum temperature of between 130°

    C. and 180°

    C. for a suitable period of time which is a function of the temperature selected for the thermomechanical working and of the nature and volume of the components subjected to the said thermomechanical working and which is between 10 seconds and 20 minutes, and a finishing step during which the vulcanization system is added by mechanical working at a temperature below the vulcanization temperature.

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