Audi is placing a focus on ensuring sustainably produced materials are at the center its innovations. According to the manufacturer, the potential for recycled materials is enormous: a car contains around 340kg of plastic; about half of that is already recyclable.
The materials development department at Audi wants to improve on that figure, with one example being the use of recycled material in its seat covers. “We want to produce a durable seat cover with outstanding quality that passes all of our product tests — and we want to produce it sustainably,” explains Audi’s Ute Grönheim, a member of the company’s materials development department, who is responsible for seat covers, where one seat cover is made out of 45 recycled,1.5L PET bottles.
When plastic bottles are returned, the recycling companies reuse only the clear ones, because they’re easier to dye. The lids come are removed, a bottle washing system washes them, then a shredder slices the bottles into small flakes. These are used to make a granulate, which is taken by yarn manufacturer to produce the polyester threads that will later become yarn.
“This granulate is essentially the same as that used for other seat covers, except this is made of recycled PET,” explains Grönheim. Another difference: the granulate is not as evenly milled and pure as the industrially produced granulate. “That can clog up the nozzles in the yarn production,” notes Grönheim, adding. “The opacity is irregular, so it is less absorbent and needs more dye.” Hence why it is more difficult and more expensive to produce recycled polyester threads.
The recycled yarn for Audi’s seats arrives on spools at the Willy Schmitz cloth factory in Mönchengladbach, Germany, where it is processed and made into a fabric. Fifty large weaving looms are in the production hall. “The design is transferred onto the loom machine from a USB stick. Then everything runs automatically,” explains Britta Gebhardt, head of design at Willy Schmitz.
For plant manager Markus Bartsch, it makes no difference whether the yarn they are working with is made of artificially created PET or recycled PET. After it’s been woven, the fabric already looks finished: it has a pattern and already feels like a seat cover. But it’s actually far from finished. The fabric first has to pass many different quality controls, many done by hand, after which the fabric is rolled up onto a core and cleaned on a 20m-long (65ft) washing system at 60°C (140°F).
In the next step, a machine glues fleece to the cloth. This process is known as laminating and is important for the seat’s comfort. “Right now, we use flame lamination. In this process; an open flame is used to melt a thin layer of foam, which is then glued onto the fabric along with the fleece,” explains Gebhardt. After the fleece is accounted for, the car seat cover is made up of up to 89% recycled plastic bottles. “Our goal for the future is to not only use fleece, but also glue that is made of recycled materials,” says Gebhardt.
After a final quality inspection and a stress test, the fabric is sent to a sewing studio which forms the fabric; the upholstery workshop stretches it over the seats. And there it is: the finished, sustainable seat made of recycled PET bottles.