Rubber vulcanizates having improved ageing properties

摘要

The invention relates to a vulcanizable rubber composition comprising a rubber, sulfur or a sulfur donor, a vulcanization accelerator, a protective agent and 0.1 phr or more of an N,N′-disubstituted p-phenylenediamine protective agent is present in the form of a salt with an acid, and the composition does not comprise an elastomeric copolymer having glycidyl groups. The invention also relates to a vulcanization process comprising mixing and heating said rubber composition and to an article of manufacture comprising the rubber vulcanizate obtained by said process. Preferably, the acid is a C₁-C₂₄ monocarboxylic acid or a C₂-C₂₄ dicarboxylic acid, more preferably a C₁₂-C₂₀ fatty acid such as stearic acid. Most preferably, the protective agent is 6PPD.