According to the report, tyres using a compound that was up to 40% crumb rubber from tyres “suffered no reduction in durability or performance when compared to the industry standard.” Truck tyres fitted to dual-drive axle tipper lorries and earthmover tyres, with a diameter of 1.6 metres, were used in the trial.
The report also claimed that re-using rubber in this way actually improved certain performance characteristics. For example, the re-claimed rubber compounds reportedly cured 20% faster and were more durable than the control tyres. The report says that the reduction in cure time and consequent savings in energy, offer future significant savings in the tyre process using re-polymerised rubber. The full report “Using waste tyre rubber in retreads at high inclusion rates” can be found on the WRAP Web site.
Steve Waite, project manager for tyres at WRAP, commented: “The U.K. produces around 130,000 waste tyres every day so testing and developing new outlets for tyre-derived rubber material is a priority for the industry. This study provides reassurance for users that high percentages of rubber crumb can successfully be incorporated into retread compounds for truck and earthmover tyres without compromising the tyres’ performance. It is especially encouraging that some of the new compounds produced during this trial have been shown to offer benefits over the original compound.”
Robin Pegden, managing director of Envirogen Technologies Ltd., the company involved with the re-polymerisation technology used in the trial, said: “A green sustainable solution now exists for the tyre industry; surface repolymerisation is the breakthrough that the waste tyre industry has always sought. This complete new approach now offers tyre companies a new ‘true green’ material that has both economic and environmental benefits in its future use.”
Mark Stevenson, business manager of Rubber Recovery Ltd. and the author of the report, added: “The results of this study overshadow those of all other similar trials to date. It is hoped this technology will now help the rubber and tyre manufacturing industry realise the potential for recycled rubber in their products.” (Tyres & Accessories/Staffordshire, U.K.)