Mechanical characterization of innovative recyclable monomaterial films and laminates for food packaging

This work has been done within the RE.MO.PACK (REcyclable MOnomaterial PACKaging) project, that focuses on the development of innovative flexible packaging structures made from a single type of polymer, such as polyolefins, that can be effectively integrated into the recycling technologies used in the industry. The OTR (Oxygen Transmission Rate) and WVTR (Water Vapour Transmission Rate) performance (i.e., the so-called ‘barrier’ properties of the film) is ensured by vacuum deposition of aluminium oxides (AlOx) and lacquering on the polymer film, while still being considered a mono-material under EU regulations. However, the success in the application of a polymeric film to seal a food tray or the shaping of a laminate into a primary packaging (i.e., in direct contact with food) are much dependent on its mechanical behaviour. Therefore, a part of the RE.MO.PACK project is dedicated to the mechanical characterisation of the different types of laminates developed within the project based on PE and with either AlOx or conventional aluminium metallization for water barrier. In particular, the following tests are performed: i) tensile testing according to the standard UNI-ISO 527-1,3 in machine (MD) and transverse (TD) directions; ii) AlOx coating adhesion through custom peel tests. The results show that the AlOx deposition do not affect the mechanical properties of the base film, and its adhesion is comparable with that of the conventional aluminium coating.