Evonik presents Life Cycle Assessment of Silica/Silane technology for Green tires

Tires are high-tech composites, and the components of the treads have a huge impact on a tire's performance. In comparison to conventional tires made of E-SBR rubber grade solely filled with carbon black, Green tires with S-SBR rubber grades and Silica/Silane technology have proven to have significantly lower rolling resistance, resulting in a reduction in fuel consumption by 5 % and thus lower CO2 emissions. Additionally, they also have better grip – particularly in wet conditions – while offering comparable durability.

The secret of success lies in the components' interaction: Silica serves as active filler in the treads and ensure wear resistance in the tire, but is actually incompatible with S-SBR rubber grades. Evonik, one of the world's leading producers of Silica and Silanes and the only company worldwide manufacturing and marketing both, solved this problem by adding Silane to chemically "couple" S-SBR rubber grades and Silica.

Next step: A Life Cycle Assessment

Green tires have already proven to have a significant impact on a vehicle's total fuel consumption. The next logical step was to examine the potential environmental impact of tire treads based on Silica/Silane and S-SBR in Green tires in comparison to tire treads based on carbon black and E-SBR not only during the use phase, but from "Cradle to Grave". To examine the environmental effects throughout the whole life cycle, Evonik has conducted a comprehensive Life Cycle Assessment (LCA), extending from the production of raw material to end-of-life.

The study analyzed impact categories such as the Global Warming Potential, the Photochemical Ozone Creation Potential, and the Primary Energy Demands. The functional unit was defined as the use of Silica/Silane and S-SBR in treads of passenger car tires over a driving distance of 150,000 km. Additionally, a sensitivity analysis was conducted with gasoline consumption, fuel savings, and lifetime as parameters.

Use phase is key to reduce emissions

According to the study, Silica/Silane technology in Green tires is able to significantly reduce emissions and environmental impacts in the basic scenario in any analyzed impact category considered relevant. Consequently, the Global Warming Potential can be reduced by 4.9 % in total over the whole life cycle; by replacing carbon black and E-SBR with Silica/Silane and S-SBR, emissions of up to 1.4 metric tons of CO2 equivalents per 150,000 km driving distance are avoidable.

The study also shows that the use phase has a key impact on the overall lifecycle in all impact categories. As Green tires with Silica/Silane components can significantly reduce fuel consumption, this technology can have a key role in reducing emissions in general.

The specialists of Evonik will be glad to answer any question relating to the Green tires at their  booth C816, at the Tire Technology Expo in Hanover between February 14 and 16.