Styrenics Circular Solutions demonstrates polystyrene’s mechanically-recycled food-grade feasibility
22 Oct 2020 --- Styrenics Circular Solutions (SCS), the value chain initiative increasing the circularity of styrenic polymers, has successfully demonstrated the mechanical recyclability of polystyrene (PS) to food contact standards.
SCS performed so-called challenge tests in cooperation with the Fraunhofer-Institute für Verfahrenstechnik und Verpackung IVV, confirming the high cleaning efficiency of the PS mechanical recycling technology for removing impurities originating from waste streams.
The test results are enabling the first application for a European Food Safety Authority (EFSA) opinion on the use of recycled polystyrene (r-PS) as food contact material.
Supercleaning technology
The SCS mechanical recycling process harnesses machine manufacturer Gneuss’ “supercleaning” technology to achieve consistently high PS recyclate purity levels.
The “supercleaning” technology’s ability to handle post-consumer PS waste from food contact packaging was “stress-tested” by adding impurities under worst-case assumptions.
The test revealed the technology’s “very good” cleaning efficiency, leading to “excellent” r-PS purity levels.
The results are supported by PS’ intrinsic properties as a low diffusion polymer, which prevents any waste impurities entering and migrating through the polymer matrix.
SCS’ demonstrations are enabling the first application for a EFSA opinion on r-PS as food contact material.
“PS boasts excellent sortability and tests have demonstrated that PS packaging waste from EU countries overwhelmingly consists of food contact items, making it an outstanding feedstock for closing the loop back into food contact packaging,” Herman Van Roost, general manager feedstock and mechanical recycling at SCS,” tells PackagingInsights.
Polystyrene plus points
High-quality r-PS provides food packaging producers with flexibility. The polymer can be used in existing industrial production processes, such as extrusion and thermoforming.
“Moreover, the PS molecule’s qualities remain stable and do not degrade in multiple mechanical recycling. We can recycle PS over and over again,” explains Frank Eisentraeger, product director PS EMEA, INEOS Styrolution, and member of the SCS working group Waste Feedstock.
“The test results are of crucial importance as they give brand owners and packaging producers full confidence that the applied mechanical recycling technology delivers the required high purity levels for their business.”
SCS members are delivering proof of concept that mechanically-recycled r-PS can serve as a drop-in solution in form, fill and seal (FFS) production lines.
“Packaging producers for the dairy application have demonstrated that the recycled polymer is not degraded at all. It behaves as a drop-in solution in existing production lines and can be used both as monolayer and as A-B-A layer application with virgin PS,” Van Roost adds.
“This enables PS to extend closed-loop food contact recycling beyond PET bottles.”
Recycled polystyrene milestone
Jens Kathmann, secretary general at SCS, describes the mechanical recyclability demonstrations as a huge milestone in styrenics' contribution to the circular economy.
“Food-grade quality r-PS combines all the well-known application, processing and environmental advantages of PS, with the added value of being a fully circular polymer.”
“This is a great attraction and value for the market. We are delighted to take the next step by filing our application with EFSA for food contact acceptance.”
In September, Greiner Packaging carried out initial trials demonstrating the feasibility of yogurt cups made from a 100 percent recycled PS-cardboard combination. The supplier says this is the “most eco-friendly and sustainable solution imaginable.”
By Joshua Poole
