Technological watch

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 bottles by a mechanical process and will be used in the construction of the tire carcass. This can completely replace conventional polyester.
Upcycling PET Bottles with Special Technology
Together with its cooperation partner and supplier OTIZ, 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. During the 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.
Topp 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."
The Recycling Process
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.
Conserving Valuable Resources
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 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.
By 2050 at the latest, Continental aims to successively use 100 percent sustainably produced materials in its tire products. With the use of recycled PET, the tire manufacturer succeeds in taking a further step toward circular economy.
"For us, waste is tomorrow’s production material as we see the model of the future in circular economy. Continental's commitment to actively shaping and driving this transformation offers us a head start for our future business and thus for our future viability," says Claus Petschick, head of sustainability at the tires business area of Continental. "Our ambition is clear: By 2050 at the latest, we want to completely close our product and resource cycles together with partners and suppliers.”
Source: Continental