Among other materials, special attention is being given to rubber and resins sourced from more sustainable origins. Both materials are essential to tyre quality and performance characteristics.
Synthetic rubber made from renewable and recycled materials, as well as responsibly sourced natural rubber, play a crucial role in more sustainable tyre production. This is due, among other reasons, to the high share of this key raw material in each tyre produced, since modern high-performance tyres contain up to 40% rubber. The specific type of rubber used in a given tyre depends largely on the component and the function it serves. Continental passenger-car tyres are made from up to 100 different raw materials, which are used, among other things, to produce up to 20 custom rubber compounds. These increasingly include recycled variants of additives and complementary raw materials, as well as circular resins that make the resulting rubber more flexible, improving overall tyre performance.
“We are closing the loop: Continental is strengthening its commitment to the circular economy and charting its path to the future,” said Jorge Almeida, Head of Sustainability at Continental Tires. “Innovative solutions allow us to use more sustainable raw materials, such as synthetic rubber made from used cooking oil or resins based on certified renewable feedstocks derived from vegetable oil,” he added.
Synthetic rubber from recycled cooking oil
Rubber is an essential commodity for global mobility. Vehicles such as cars, trucks, bicycles, and e-bikes rely on rubber tyres to move, as do motorcycles, forklifts, and port cranes. The components that make up a tyre consist of various types of rubber covering a wide range of applications.
Continental mainly uses two rubber categories, each offering specific technological advantages for particular tyre components: natural rubber and synthetic rubber. Natural rubber—the type traditionally used in tyre production—is used, for example, in the tread of car and truck tyres, where the rubber must be extremely durable. Its special properties include impact resistance and long service life, thanks to stress-induced crystallisation inherent to natural rubber. This unique characteristic of natural rubber cannot yet be reproduced artificially.
Meanwhile, synthetic rubber is incorporated into passenger-car tyre treads alongside natural rubber due to its superior braking and rolling resistance performance. Tyre manufacturers are increasingly using synthetic rubber from more sustainable sources, such as pyrolysis oil obtained from end-of-life tyres or from used cooking oil. The feedstocks for this more sustainable synthetic rubber are sourced from suppliers such as Synthos and TotalEnergies Cray Valley, who apply a mass-balance approach that recognises sustainable sources certified by ISCC PLUS (International Sustainability and Carbon Certification). The production processes and raw materials used to manufacture the supplied synthetic rubber comply with this system.
Circular resins and sustainable additives
Continental takes a holistic approach to tyre development. This includes ensuring that all raw materials come from more sustainable sources. For example, there are special resins for almost all rubber compounds that enable an optimal balance between tyre elasticity and strength. Resins play a crucial role in unlocking the full performance of rubber compounds, for instance by improving wet grip, abrasion resistance, and rolling resistance—thereby reducing vehicle energy consumption. Continental already uses circular resins produced by suppliers such as TotalEnergies Cray Valley, which are ISCC PLUS certified, supporting the development of renewable feedstocks from vegetable oils or used cooking oil throughout the value chain.
In addition to resins, certain additives are also an indispensable part of tyre production at Continental. They are used, for example, to protect rubber during vulcanization from the side effects of heat or oxygen. Continental is the first tyre manufacturer to use LANXESS’s TMQ rubber additive, certified by ISCC PLUS, while maintaining its quality and performance standards. According to life-cycle assessments, this additive—produced from feedstocks such as bio-circular acetone—has a carbon footprint more than 30% lower than its conventionally produced counterpart. Bio-circular acetone is derived from bio-based waste, such as recycled cooking oil.
The use of these sustainable materials is possible, among other factors, thanks to the mass-balance approach, which Continental applies systematically to advance its goal of using at least 40% renewable and recycled raw materials in tyre production. This approach involves mixing fossil, renewable, and recycled materials during manufacturing and tracking them throughout the value chain. This enables the company to attribute the use of renewable and recycled feedstocks to the final product and thereby document accurately—and progressively increase—the use of ISCC PLUS certified materials.
“The mass-balance approach allows us to efficiently manage the complexity of our raw-material portfolio and track how these feedstocks are used across multiple production sites in a wide range of markets,” explained Matthias Haufe, Head of Materials Development and Industrialisation at Continental Tires. “In this way, we can steadily increase the share of renewable and recycled materials in our tyre production and transparently document the progress we are making,” he said.
