Following a 2021 study on the recyclability of co-extruded polyethylene/polyamide (PE/PA) multilayer films, independent research institute cyclos HTP GmbH has completed a further extensive study on the recyclability of multilayer films containing polyamide 6(PA6) and ethylvinylalcohol copolymer (EVOH). Basf commissioned research on co-extruded PE/PA6/EVOH high-barrier films and laminated PA6/PE films in household packaging waste. It has now been shown that both film types are also suitable for recycling in polyethylene film streams.

Dr. Matthias Zorn, market development Manager of polyamide for extrusion applications at BASF, said: "The results show that PE film waste streams containing PA can be treated without major adjustments to the recycling process. This certification confirms that the current film manufacturer has achieved the recycling of PA-containing film waste streams."

Compatibilizers play an important role by being added to the laminate structure to enable the PA component to be distributed in the PE matrix. In the co-extruded structure, the existing bond layer in the film used to bond PA and PE becomes an effective compatibilizer during the recovery process. "Polyamide is even considered a valuable material in the polyethylene recovered by cyclos HTP if additional PE-g-MAH is added as a compatibilizer during the primary film production process," says Matthias Zorn.

This research on bonded laminated PE/PA films, carried out in collaboration with SUDPACK, a leading manufacturer of high-performance films, clearly shows that these films, which were previously considered unrecyclable, can also become recyclable. In this project, Henkel's laminated adhesive was used. According to new research, a variety of PA-containing packaging can now be proven to be recyclable.

Due to its unique properties, polyamides reduce the amount of material used in packaging applications, thus helping to reduce packaging waste. They also improve the mechanical, thermal and processability of packaging. Although PE/PA/EVOH films are used in many cheese and sausage packaging that require high oxygen barrier, in this area, laminated structures are mainly found in printed film packaging.

Last year, the recyclability of co-extruded PE/PA films was recognized in Germany under Article 21 (3) of VerpackG, which determines the recyclability of packaging affected by system participation. This certification is another important basis for fact-based classification of polyamides in packaging. The CEN Standardization Group is developing guidelines for "recycling by design" at the European level, and the central agency Packaging Registry develops lower standards for assessing recyclability in Germany every year.