Use of Recycled Tyre Material in Natural Rubber based Tyre Tread Cap Compound: Part I (with Ground Crumb Rubber)

Abstract

For both environmental and economic reasons, there is a continuing broad-based interest in the recycling of scrap rubber and therefore in the development of recycling technologies. In the present work three different sizes of mechanically ground Indian crumb rubbers were used in a natural rubber (NR) based tyre tread cap compound. Varying doses of crumb rubber were used as an additional compounding ingredient. The minimum torque and Mooney viscosity values were marginally increased with increasing dose and mesh size of crumb rubber. In a Rubber Process Analyser (RPA) study, the Payne effect before curing was marginally higher for compounds containing crumb rubber, while, after curing a comparable Payne effect was observed with respect to the control compound without having crumb rubber. A marginal deterioration in tensile strength, fatigue to failure and abrasion properties was observed. At all levels of usage, the 100 mesh size ground crumb rubber retained the properties better than other lower mesh size crumb rubbers.