Why rLDPE Matters for Flexible Packaging
Learn how Reactive Recycling is the enabling technology for greater rLDPE content in blown film processing.
The plastics industry has long faced a challenge when it comes to recycling low density polyethylene (LDPE) for flexible packaging applications. While recycling is essential for sustainability, rLDPE suffers from degraded polymer chains, which compromise its melt strength and processability. Manufacturers have been limited by the amount of recyclate that can be incorporated without sacrificing quality. Recent advances in reactive masterbatch additives are changing this landscape, enabling significantly greater recyclate content in blown film extrusion processes.
A new video from Nexam Chemical [1] offers a clear illustration of blown film challenges and solutions. The journey of LDPE feedstock is shown, as it is fed into an extruder, melted, and blown into thin films. The process demands materials with specific melt flow rate and melt strength to maintain a stable bubble and produce consistent film thickness. rLDPE, due to shortened polymer chains from prior processing and thermal history, typically exhibits higher melt flow rates and weaker melt strength. This makes it difficult to maintain bubble stability, leading to film defects, reduced mechanical performance, and other issues including post-production print quality.
Reactive masterbatches are additives that rebuild molecular weight during the extrusion process. They reconnect fragmented chains in situ and restore both melt viscosity and melt strength. The video highlights how this technology, dubbed Reactive Recycling by Nexam Chemical[2], is applied in practice with a customer example from Kullaplast AB[3], one of Sweden’s largest producers of polyethylene films. By incorporating reactive masterbatches in solid pellet form into their production lines, Kullaplast successfully increased rLDPE content to 50+% without compromising quality or production efficiency.
The benefits of this approach are multifold:
Improved melt strength allows for more stable bubble formation during extrusion, which is essential for producing uniform, defect-free films. Bubble stability also enables higher throughput and reduces downtime caused by breaks or film inconsistencies.
Restored viscosity and mechanical properties allow the final films to meet the demanding requirements of packaging applications, including strength, flexibility, and clarity.
By enabling higher recycled content, manufacturers reduce their reliance on prime resins, lowering raw material costs and carbon footprints.
The video also emphasizes the practical integration of this technology into existing production lines. The reactive masterbatch is introduced directly into the extruder alongside the blended vLDPE/rLDPE feedstock, requiring no major equipment modifications. Seamless integration is crucial for widespread adoption, as it minimizes process changes or asset additions.
Moreover, reactive masterbatches are designed to be safe and peroxide-free, ensuring no harmful byproducts are generated during processing, aligning with industry standards and regulatory requirements,
The combination of reactive masterbatches and advanced processing techniques created a breakthrough in the use of rLDPE for blown film extrusion. The Kullaplast example demonstrates that post-consumer recyclate (PCR) can perform on par with prime resins in demanding film applications, supporting industry goals of circularity and sustainability.
Want to learn more about Reactive Recycling technology for rLDPE, other polyolefins, and polyesters? Reach out today for an initial consultation.