Recyclable Packaging from the Twin-Screw Extruder
Foamed rPET is the Alternative to Conventional Beverage Cartons
Recycling of beverage packaging poses special challenges to the industry: the layers cannot be properly separated from each other in the recycling process, making recycling difficult. As an alternative, Leistritz Extrusionstechnik GmbH, Nuremberg, Germany, showed foamed rPET (recycled polyethylene terephthalate) at this year's Interplastica in Moscow, Russia, at the end of January. The plant technology, which was developed and tested together with partners, enables the extrusion of rPET pellets into foamed films.
Besides Leistritz, recycling specialist NGR Next Generation Recyclingmaschinen GmbH, Feldkirchen, Austria, film manufacturer Kuhne Sankt Augustin, Germany, are involved in this project. As a "young" company, ForPET will establish a commercial development center in Russia together with investors. It is expected that the final development will be completed by the end of 2020. “Our intention was to create a material that could be recycled without any limitations. We have successfully achieved this and in the meantime we have had it patented worldwide,” says Sergey Nikitenko, Managing Director ForPET. According to the company, the film represents a 100% recyclable alternative to conventional composite materials.
Mono Material Facilitates Recyclability
Beverage packagings are relatively light and yet robust. Above all, they ensure a long shelf life and the protection of the contents. To ensure that a beverage carton meets all the required properties, different materials are combined to form a composite. In addition to wood, for example, several layers of polyethylene are used. In order to be able to store the contents without using preservatives for a longer period without cooling, an aluminum film layer is incorporated as a gas barrier.
However, it is precisely this film mixture that poses special challenges to the technology. With a mono-material packaging made of foamed rPET, on the one hand, largely all functions can be covered with just one material, and on the other hand, the separation of – if necessary – additional barrier layers such as aluminum can be solved very efficiently and economically in the melt process.
Production of the Film
Several process steps are necessary to produce the foamed rPET film: the rPET flakes are prepared with additives in the Leistritz twin-screw extruder. In combination with a liquid state polycondensation (LSP) reactor from NGR, a tailor-made granulate or a melt for downstream foaming is produced. The melt is also loaded with a physical blowing agent in a Leistritz twin-screw extruder. The foamed film is then produced in Kuhne's plant section.
"We are currently working with investors to establish a commercial development center in Russia," Nikitenko explains the next steps. It is expected that the final development will be completed by the end of 2020. After that, the first commercial products will also find their way onto the market.
According to Sven Wolf, Managing Director at Leistritz Extrusionstechnik GmbH, international brands such as one of the world's leading beverage manufacturers, but also institutional investors have already shown great interest on the occasion of the product's first design presentation at the Leistritz booth at the K Show 2019.