COMPATIBILISERS | MATERIALS


Additives improve mixed recycling feedstock


Compatibilisers and coupling agents act at the interface of dissimilar materials to improve processing and properties. Jennifer Markarian reports


One of the challenges for plastics recycling is that different types of polymers don’t always mix well together. The resulting blend may have processing difficulties, poor appearance, or poor physical properties. Mixed materials are a concern for post-consumer recycling and also post-industrial, or post-consumer recycling of multilayer materials. Compatibilisers and coupling agents – added either in the original, virgin material or at the recyclate compounding step – can solve some of these problems. Not all additives work in every blend, however, and they must be carefully selected to optimise a formulation. Jeroen Frederix, Market Development Manager,


Circular Economy, for SI Group sees a need for compatibilisers in recycled compounds particularly


www.plasticsrecyclingworld.com


for post-consumer recyclate (PCR). “Although sorting and washing technologies are advancing, there is a need for specific compatibilisers to handle impurities and cross-contaminations that remain in the PCR stream after the washing step.” Avient’s latest addition to its Additives for


Recycling (A4R) portfolio is Cesa Unify A4R, a compatibiliser additive masterbatch developed to enhance and support the use of recycled polyole- fins. The additive helps bring together incompat- ible polymers, such as PP and PE, into a homog- enous polymer mixture and increases mechanical strength by keeping the rPP stiffness high, to bring the blend’s properties closer to those of virgin polymer. This improvement in the compound’s properties enables recyclers to attain higher-quality


Main image: Getting materials to mix is the focus for specialist additive companies


May/June 2024 | PLASTICS RECYCLING WORLD 25


IMAGE: SHUTTERSTOCK/ALEXA_SPACE


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