pinfa sparks: recycling strategies for FRs
Over 60 participants at pinfa's 2nd ‘sparks’ webinar discussed recycling of PIN FRs with Nacho Montesinos Beltrán, AIMPLAS. Mr. Montesinos Beltrán, an expert in polymer recycling chemistry, underlined the difficulties of recycling post-consumer plastics which are an increasingly complex mixture of different polymers, additives and contaminants. Improving sorting is the first priority, but has limits because some items are multi-layered with different compounds which are bonded and cannot be separated.
Mechanical recycling (melt – reprocess) can be an option, but only if input materials are identical (closed-loop collection) or well sorted. Challenges are deterioration of polymers in ageing and reprocessing, mixing of polymers, dilution or breakdown of additives. Testing of some PIN flame retardants has shown compatibility with mechanical recycling, as they are designed to be resistant to ageing and processing conditions (see pinfa Recycling Brochure).
Other plastics recycling processes can address more complex mixtures of different polymers and additives.
Solvent recycling uses a cascade of different target solvents to progressively dissolve or depolymerise, then to separate, different polymers. Specifically adapted temperature and pressure conditions can improve separation. Organic PIN flame retardants can be separated and recovered by appropriately targeted solvent conditions.
Pyrolysis recycling can break down mixtures of different polymers to monomers and allow recovery of inorganic and some other PIN flame retardants.
Enzyme breakdown of plastics may in the future provide a low environmental impact route to recycling plastics and additives.
Halogenated flame retardants pose obstacles to recycling, by possible release of corrosive compounds during processing and because of the legal obligation to separate plastics containing brominated FRs under the WEEE Directive 2012/19.
In conclusion, the selection of the most appropriate recycling and flame-retardant removal/recovery strategy must begin with a detailed definition of the input waste stream, including the specific polymers, additives, contaminants, and flame retardants present. Only through a clear understanding of the composition of the incoming material can an appropriate recycling route be selected, enabling efficient flame retardant removal or recovery and ultimately ensuring a suitable upcycling approach for high-value plastic compounds
pinfa sparks 2nd webinar, Thursday 7 May 14h-14h45 (CEST), Closing the Loop: Recycling Strategies for Flame Retardant Additives, with Nacho Montesinos Beltrán, AIMPLAS. Watch online https://www.pinfa.eu/resources/presentations/
