Sustainable materials in tire production include recycled rubber, rice husks and plastic bottles
by CM staff
Continental is aiming for fully circular operations in its tire production by 2050.
MISSISSAUGA — By 2050 at the latest, all tires will be made of sustainable materials. There is still a long way to go until then. But step by step, it is already becoming apparent which raw materials will find their way into tire construction in the future. These include waste products from agriculture – such as the ash from rice husks – rubber from dandelions, recycled rubber or PET bottles.
“Continental is on the road toward becoming the most progressive manufacturer in the tire industry in terms of sustainability,” said Claus Petschick, Head of Sustainability at Continental Tires. “At the latest, we aim to use 100 per cent sustainable materials in our tire products by 2050. Our innovative power enables us to break new and even more sustainable ground. This innovative power encompasses everything from the origin and sourcing of our materials to the reuse and recycling of our tires.”
Around 15 to 20 per cent renewable or recycled materials are used in a standard passenger car tire from Continental currently. Continental analyzes and reviews all raw materials used in tire production to increase the proportion of sustainable materials and conserve valuable resources.
Depending on the application, season, and environment, tires must fulfill specific requirements. These elements can be seen in, for example, the tread design. But in other areas – the composition of the rubber compound, for example – these changes are not so readily visible. Passenger car tires from Continental consist of as many as a hundred different raw materials.
Natural rubber is essential for ensuring outstanding tire performance. This natural product accounts for between 10 and 40 per cent of the entire weight of modern high-performance tires. Its unique properties include a high level of strength and durability, which are caused by the strain-induced crystallization of the rubber. The tire industry is the biggest consumer of global rubber production, accounting for more than 70 per cent. However, Continental considers natural rubber a sustainable material only if it is sourced responsibly. Therefore, the company employs an integrated approach to make natural rubber’s fragmented supply chains more sustainable, including using digital technology, local involvement and close collaboration with capable partners with the goal of improving transparency and traceability along the entire value chain.
With its Taraxagum project, Continental is pursuing an approach to ensure that it can become less dependent on natural rubber grown primarily in Southeast Asia. The tire manufacturer is working alongside partners on industrializing the extraction of natural rubber from specially cultivated dandelion plants.
At the latest, Continental is aiming for fully circular operations in its tire production by 2050. In addition to using renewable materials, the company is working systematically on using recycled raw materials in tire production. This process is intended to ensure that carbon black – another crucial filler in rubber compounds – can be obtained on a large scale. Continental recently signed a development agreement with Pyrum Innovations, intending further to optimize the recycling of materials from old tires. To do this, Pyrum breaks the old tires down into their constituent parts in an industrial furnace using a special pyrolysis process. In this way, valuable raw materials contained in end-of-life tires can be extracted and recycled. Both companies are working towards obtaining high-quality raw materials from the pyrolysis oil obtained for Continental’s tire production in the medium term, in addition to the direct use of high-quality carbon black. In the long term, the premium tire manufacturer and Pyrum are aiming to establish a closed-loop circular economy concept for recycling old tires.
In addition to pyrolysis, Continental uses mechanical processing of end-of-life tires. Rubber, steel and textile cord, in particular, are separated, in a highly sophisticated process, from one another. The rubber is then prepared for reuse as part of new rubber compounds.
Continental has a long history of consistently introducing end-of-life tires into the circular economy to conserve resources and the environment. A material known as “Conti-Reclaim” has been obtained as part of the truck tire retreading process at the company’s plant in Stöcken in Hanover since 2013. It has been used in tire production at Continental for years. To expand the range of applications for recycled rubber and optimize the properties for the various application fields, Continental uses “Conti-Reclaim” and recycled rubber from other suppliers.
Recycled plastic bottles in the tire casing
“Recycled raw materials will play a big role in making tires more sustainable. We use recycled materials whenever possible. Comparable quality and material properties to conventional raw materials are crucial for us,” says Petschick.
For example, Continental works with partners to obtain high-quality polyester yarn for its tires from recycled PET bottles. PET bottles often end up in incinerators or landfills otherwise. With its ContiRe.Tex technology, the tire manufacturer has developed a more energy-efficient and eco-friendly alternative that allows it to reuse between nine and fifteen plastic bottles for each tire, depending on the tire size. Recycled PET has already replaced conventional polyester in the structures of some tire casings. The PET bottles used are sourced exclusively from regions with no closed recycling loop.
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