SPECIAL REPORT: SUSTAINABILITY LIGHT WORK With sustainable materials and technologies high on the development agenda for tire makers, TTI headed to CES in January 2024 to speak with Dr Marcela Castaño, lead applied researcher, sustainable materials and circular economy at the Bridgestone Americas Technical Center, for the latest on the company’s Enliten materials research By GRAHAM HEEPS What specific technologies are involved in Enliten? The renewable materials include a vegetable oil that comes from soybeans. This is in the Turanza EV passenger car tire that was launched early last year. Another material comes from residue from agricultural processes – rice husks from which you can extract a silica reinforcement. Other tire makers have been using that; now Bridgestone is going to as well. That will come sooner in Europe than in the US market, maybe in the next two years. It’s not just important that these materials are coming from renewable or bio sources, we must consider the impact of the extraction Above: Bridgestone has been confirmed as the sole tire provider for Formula E from 2026/27, a deal which will see the tire maker bring its Enliten materials suite to the all-electric series of these raw materials, too – for example, water use, CO 2 impact, land use and social aspects. rubber, we have the pilot-scale guayule rubber project in Arizona that we will commercialize by 2030. What’s happening on the polymer side? Enliten is about the use of recycled and renewable content but also reducing rolling resistance and increasing wear life while keeping optimal tire performance. We are using new, fossil-based synthetic polymers that have a functionalization that interacts much better with the silica, reducing the rolling resistance and increasing the wear life of the tire. The Turanza EV has it and there are more tires to come using the same technology. Then for natural How about projects from end-of-life tires? We are already implementing recycled carbon black and our goal is to transform pyrolysis oil from end-of-life tires into monomers that are the building blocks for synthetic rubber. Right now, we are using hard-to-recycle plastics like plastic bags or wrap. Our [Firestone Firehawk] IndyCar race tires use a synthetic rubber created with ISCC+ certified recycled butadiene, and the Turanza EV also uses a synthetic polymer sourced 28 www.tiretechnologyinternational.com March 2024