Building on studies carried out in 2021 that confirmed the recyclability of coextruded polyethylene/polyamide (PE/PA) multilayer film, the latest tests commissioned by BASF (Ludwigshafen, Germany; www.basf.com) with coextruded PE/PA 6/EVOH high-barrier film as well as laminated PA 6/PE film have produced further proof that the two film types can be recycled in the PE film stream without significant adjustments to the process, the chemicals and plastics giant says.

The results achieved by cyclos-HTP (Aachen; www.cyclos-htp.de), the German institute for recyclability and product responsibility, uphold the standard market practice of PA-containing film waste already being recycled by film manufacturers, commented Matthias Zorn, senior manager market development polyamides for extrusion applications at BASF.

As Zorn explains, the compatibiliser incorporated into laminated structures to enable distribution of the PA component in the PE matrix plays an important role. In coextruded structures, the already present tie layer used to bond PA and PE in the film becomes an effective compatibiliser during the recycling process. 

If additional functionalised polyethylene (PE-g-MAH) is added as a compatibiliser during primary film production, the polyamide is even recognised as a valuable material in the polyethylene recyclate by cyclos-HTP, he noted. 

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The study on adhesive-laminated PE/PA film carried out for BASF by high-performance films manufacturer Südpack (Ochsenhausen, Germany; www.suedpack.com) is said to have “clearly shown” that film types previously considered non-recyclable can be made recycling-ready.

Due to their unique property profile, polyamides reduce the amount of material used in packaging applications and thus help to reduce packaging waste, BASF says. What’s more, they also improve the mechanical, thermal, and processing properties of the packaging. 

In 2022, the German minimum standard for determining the recyclability of packaging for the first time recognised the recyclability of coextruded PE/PA film. Previously, PA had been labelled incompatible with waste streams containing polyethylene-based polymers.

The Ludwigshafen group says the newest test results will form an important fundament for fact-based development of European Design for Recycling guidelines, as a broad portfolio of PA-containing packaging can now be certified.