Technology Spotlight: Episode 2
Upcycling of recycled plastics to restore properties and close the loop on circular economy
Solutions for recycled plastics traditionally focus upon mechanical or chemical recycling routes, each with their pros and cons.
Mechanical recycling involves sorting, washing, shredding and/or grinding of waste plastics for subsequent handoff to producers that fabricate bottles, packaging, fibers, and other shapes. Industrial and post-consumer recyclate streams are somewhat homogenous and considered ready for compounding. However, these plastics become downgraded, negatively impacting processing metrics such as intrinsic viscosity and melt flow index.
Chemical recycling essentially converts the waste plastic back to its basic monomeric building blocks. These secondary raw materials can be used for fuel; to manufacture other chemicals; or be polymerized to form new feedstocks. Reduced landfill mass is a clear benefit, but the dedicated assets and high energy consumption required for chemical recycling are limiting factors.
Enter Reactive Recycling, a newer technology developed by Nexam Chemical AB for repairing and upcycling waste plastics via existing processing equipment. Melt processing is the simplest operation, either in single- or twin-screw extruders, utilizing thermally active masterbatches that react with the melt via chain extension, long-chain branching, or crosslinking. Processing is readily enhanced, as measured by increased intrinsic viscosity or melt flow reduction (yes, reduction!), enabling the manufacture of stable blown films, bottles, piping, etc. There are no by-products due to the addition reaction of the active ingredients within the masterbatch. Formulations can be customized to match the particular plastic being processed, e.g. polyethylene, polypropylene, polyester, nylon, etc.
In addition to enhanced flow properties for a given stream, multiple feedstocks can be individually adjusted for consistent performance, improving supply chain security. Since these materials often contain varying amounts of contaminants e.g. other plastics, Reactive Recycling provides the key to compatibilization. Recycled content of molded parts can be increased by mixing prime and recycled streams, an important enabler for sustainability programs.
Reactive Recycling may also contribute to improved mechanical properties of molded parts, although your mileage may vary.
So what’s the final takeaway for Reactive Recycling?
Ideal complement to mechanical recycling
Allows for a wider selection of industrial and PCR feedstocks
Upgrades lower-quality streams for production of higher-value molded parts
Improves processing efficiency
Lowers energy consumption and reduces processing time, specifically for rPET
Provides an additional tool for closed loop recycling and circular economy
Not bad for a day’s work!
Care to learn more about how to include Reactive Recycling in your mechanical recycling value chain? Want to see some data to support my claims? Reach out for a free initial consultation today.