RECYCLING | ADDITIVES


Additives rise to the recycling challenge


Additives aim to restore the properties needed to make mechanically recycled plastics fully functional in the circular economy. Jennifer Markarian reports


Recycled polymer, particularly from post-consumer recyclate (PCR), is notoriously challenging for both compounders and processors—high variability in viscosity, contamination, degradation and discol- oration, for example, make it far more difficult to produce a quality compound capable of producing parts with consistent high quality. Nevertheless, use of and demand for PCR is increasing, and com- pounders are calling upon a wide range of addi- tives to lift performance and enhance quality. Additives are also proving useful for handling post-industrial recyclate (PIR). Such materials could be sourced from in-house regrind or other converted plastics goods that are collected as waste. PIR use is already well-established in some areas of the plastics industry, but new additives can bring improvements that can open more opportunities.


www.plasticsrecyclingworld.com


Antioxidants play a vital role in polymer stabilisa-


tion, protecting from thermal degradation during processing and end use as well as preventing degradation by UV exposure. Stabilising recycled polymer, however, requires a different way of thinking. “Polymer producers have spent decades optimising the loading of additives in their plastics without recycling in mind. As a result, polymer is well-stabilised for the immediate application, but lacks enough residual stabilisation to ensure recyclability,” says Tad Finnegan, Senior Technical Manager at BASF. “This understabilisation leads to oxidation of the


polymer, and that impacts the performance of the recycled polymer in the end-use application. To address this challenge, polymer producers are going to need to re-think how they stabilise the materials they produce to ensure future recyclability.”


Main image: Getting the maximum value from post-consumer recycled plastic needs careful additive selection


� October 2022 | PLASTICS RECYCLING WORLD 47


IMAGE: SHUTTERSTOCK


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