Following the success of the first set of challenge tests, the styrenics value chain initiative Styrenics Circular Solutions (SCS) has now concluded a second round of testing aimed at showing that polystyrene could be mechanically recycled into a food-contact grade of regranulate.
The first tests were conducted in October 2020, using the supercleaning technology developed by Gneuss. The tests involved stress testing the ability of the technology to handle post-consumer polystyrene waste from food contact packaging, after which further challenges were performed by adding impurities under worst-case assumptions. The supercleaning technology passed with flying colours.
These further tests were carried out in collaboration with Austria-based plastics recycling machinery manufacturer, NGR, and process engineering and packaging research institute, Fraunhofer IVV. The challenge test demonstrated the outstanding cleaning efficiency of NGR’s technology, and yielded, as before, outstandingly pure rPS.
These results are attributable to the intrinsic properties of polystyrene - as a low diffusion polymer, waste impurities do not enter into or migrate through the polymer matrix.
“This second challenge test completely supports the findings of the first test,” said Frank Eisentraeger, Product Director PS EMEA, INEOS Styrolution and member of SCS working group Waste Feedstock.
“These excellent results show once again that mechanical recycling of polystyrene delivers the required high purity levels needed by converters, brand-owners and retailers for direct food contact.” He added that this was ‘a truly circular polymer’, able to be recycled back into its original - food contact - application, with no degradation.
SCS is now planning to file two separate applications for EU authorisation of rPS as food contact material.
“We now have an industrial blueprint of a flexible mechanical recycling plant with different technology options for investors,” said Jens Kathmann, Secretary General SCS.
“We are looking forward to an acceleration of industrial initiatives, especially with the knowledge that mechanically recycled polystyrene has an outstanding environmental footprint.”