Continental to use recycled PET bottles in tire production as of 2022
Continental enables the use of reprocessed polyester obtained from recycled plastic bottles in its tire production as of 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 tire carcass. This can completely replace conventional polyester.
Together with its cooperation partner and supplier OTIZ, a fiber specialist and textile manufacturer, Continental 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.
“As early as 2022, we will be able to use material obtained from recycled PET bottles in tire production. In our innovative recycling process, the fibers are spun from recycled PET without having to break the material down into its components beforehand,” says Dr. Andreas Topp, responsible for materials, process development and industrialization in Continental’s Tires business area. He adds: “Already at this year’s IAA MOBILITY in Munich, we will present a highly innovative concept tire 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.”
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 polymerization 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 tire tests conducted by Continental have shown that secondary raw material fibers perform equally well as the fibers used up to now. They have the same quality as virgin PET, are just as stable, and are particularly suitable for tires due to their breaking strength, toughness and thermal stability.
Conventional PET has long been used as a material in car tire 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 tire construction: today, a conventional passenger car tire consists of around 400 grams of polyester yarn. This means that more than 60 recycled PET bottles can be used for a complete set of vehicle tires in the future.