Whether for milk, sauce or juices, beverage packaging can be found in every household. They are relatively light (only about 30 grams in average) and yet robust. Above all, they ensure a long shelf life and the protection of the contents. If the packaging is empty, we dispose it in the recycling bin. The cycle starts all over again. At least that's what one would like to think. However, it's not that simple - except foamed recycled PET (rPET) is used in the packaging.
The problem of recycling
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: The layers cannot be properly separated from each other in the recycling process, making recycling
difficult. According to the German Environmental Aid (DUH), only 36% of this packaging was recycled in 2016 - in part only thermally. However, this thermal recovery is not a recycling measure according to the EU Waste Directive, as no new products are created as a result.
The alternative: Foamed rPET film
"The solution is foamed rPET as a replacement for the carton", says Sven Wolf, Managing Director at Leistritz Extrusionstechnik GmbH. "The idea for this came from ForPET, a very innovative Russian company. Interestingly, the main reason was not the recycling, but the reduction of wood fibers in disposable packaging". As there is no pronounced recycling of paper in Russia, new wood fibers are largely used for the production of beverage cartons. Excessive wood consumption in Siberia, however, leads to excessive timber extraction and thus to desertification of the landscape. This in turn also affects the reduction of permafrost soils with corresponding far-reaching environmental problems.
Using rPET for beverage cartons came about in various discussions and was ultimately patented worldwide by ForPET as a product. For the implementation, a recognized innovator and system supplier - Leistritz Extrusionstechnik GmbH - was chosen. "Together with our partners, we tested a system technology that facilitates the extrusion of rPET pellets into high-quality foam films. This represents a 100% recyclable alternative to conventional composite materials."
Besides Leistritz, recycling specialist NGR and film manufacturer Kuhne are involved in this trend-setting development project. As a "young" and innovative 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. After that, the first commercial products will find their way into the market. 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 stand at the K Show 2019.
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.
Several process steps are necessary for the production of the foamed rPET film: The preparation of the rPET flakes with appropriate additives takes place in a Leistritz twin-screw extruder. In combination with an LSP reactor (Liquid State Polycondensation) from NGR, a tailor-made pellet or melt for downstream foaming is produced. The loading of the melt with a physical blowing agent also takes place in a Leistritz twin-screw extruder. From there, the melt reaches the film extrusion downstream unit of Kuhne. This is where the foam film is produced, which can be further processed and is fully recyclable.