Green tyres with S-SBR rubber grades and Evonik’s silica/silane combination technology have proven to have significantly lower rolling resistance, resulting in a reduction in fuel consumption by 5% and thus lower carbon dioxide (CO2) emissions compared to conventional tyres made of E-SBR rubber grade solely filled with carbon black. These tyresalso have better grip – particularly in wet conditions – while offering comparable durability.
Silica serves as active filler in the treads and ensure wear resistance in the tyre, 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, added silane to chemically “couple” S-SBR rubber grades and silica.
Green tyres have already proven to have a significant impact on a vehicle’s total fuel consumption. The next step was to examine the potential environmental impact of tyre treads based on silica/silane and S-SBR in green tyres in comparison to tyre 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 analysed 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 tyres over a driving distance of 150,000 km. In addition, a sensitivity analysis was conducted with gasoline consumption, fuel savings, and lifetime as parameters.
According to the study, Evonik’s silica/silane technology in green tyres is able to significantly reduce emissions and environmental impacts in the basic scenario in any analysed 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 tonnes 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 tyres with silica/silane components can significantly reduce fuel consumption, this technology can have a key role in reducing emissions in general.
Evonik will be presenting its silica/silane technology in green tyres at the Tire Technology Expo in Hanover, Germany from February 14 to 16 at their booth, C816.