Continental is using reprocessed polyester derived from recycled plastic bottles in its tyre production by 2022. The new sustainable polyester yarn will be obtained from polyethylene terephthalate (PET) bottles by a mechanical process and will be used in the construction of the tyre carcass, Continental explained. This can completely replace conventional polyester.
Together with its cooperation partner and supplier OTIZ, a fibre specialist and textile manufacturer, the premium tyre manufacturer has developed a special technology to recycle PET bottles without previously necessary intermediate chemical steps and to make the polyester yarn functional for the high mechanical requirements of the tire. In the course of so-called upcycling, a PET bottle becomes a high-performance PET material.
Dr. Andreas Topp who is responsible for materials, process development and industrialisation in Continental’s Tyres business area informs that as early as 2022, the company will be able to use material obtained from recycled PET bottles in tyre production. Through an innovative recycling process, the fibres are spun from recycled PET without having to break the material down into its components beforehand. “Already at this year’s IAA MOBILITY in Munich, we will present a highly innovative concept tyre with polyester yarn made from recycled PET bottles. With the use of recycled polyester yarn, we are taking another important step in the direction of cross-product circular economy, “ Topp said.
As part of the recycling process, the bottles are first sorted, caps removed and finally mechanically cleaned. After mechanical shredding, they are melted down and granulated; this is followed by solid state polymerisation and a modified spinning process. “Our modified manufacturing process enables us to obtain polyester yarn for tire construction from PET bottles without any polymerization process from monomers,” explains Dr Derren Huang, Chief of Research and Development at OTIZ.
Laboratory and tyre tests conducted by Continental have shown that secondary raw material fibres perform equally well as the fibres used up to now. They have the same quality as virgin PET, are just as stable, and are particularly suitable for tyres due to their breaking strength, toughness and thermal stability.
Conventional PET has long been used as a material in car tyre construction because it retains its shape even under high loads and temperatures and thus ensures safety at all driving speeds. The use of recycled PET conserves valuable resources in tyre construction: today, a conventional passenger car tyre consists of around 400 g of polyester yarn. This means that more than 60 recycled PET bottles can be used for a complete set of vehicle tyres in the future.