From multilayer LDPE/EVOH flexible film scraps to new multilayer films

This study explores the mechanical and optical properties of multilayer films incorporating recycled materials, mimicking the structure of industrial films. Using a coextrusion blown film line with a three-layer ABC configuration extrusion head, films were produced using two different recycled multilayer films, from post-industrial scraps, in layers A and B and virgin low-density polyethylene (LDPE) in one of the external layers (C). These recycles result from multilayer films mainly constituted of LDPE; one has also linear-LDPE (LLDPE) Metallocene, and the other has Ethylene Vinyl Alcohol (EVOH). Both recycled materials enabled to maintain blown film extrusion process stability during film production. The multilayer films produced with the incorporation of recycles were characterized using scanning electron microscopy (SEM), haze and gloss measurements, and tensile tests. Films with Recycled EVOH presented haze values much higher than those obtained for the Recycled Metallocene. However, all films presented good mechanical properties when compared to single layer virgin LDPE film. Anisotropic behaviour was observed, emphasizing the directional dependence of mechanical properties. The findings provide insights into the behaviour of multilayer films with recycled content, offering valuable information for the development of sustainable packaging solutions. Multilayer film production of recycled materials (recycled LLDPE Metallocene (M) and EVOH (M)) from post industrial waste, to evaluate optical and mechanical properties for comparison purposes with a 100 % virgin LDPE control film. • Multilayer films were produced via coextrusion with a three-layer ABC configuration. • Recycled multilayer films containing EVOH and Metallocene were successfully incorporated. • Films with recycled EVOH exhibited significantly higher haze values, but maintained good mechanical performance. • The extrusion process remained stable with the inclusion of both recycled materials. • Mechanical properties were comparable to virgin LDPE films.