In packaging applications, nowadays typically multilayer films are applied to fulfil a variety of requirements like tenacity, printability, barrier properties and food contact approval. One persistent problem with such films is their recycling, even as low contaminated post-industrial waste, which is present as start-up materials and edge-trim, as the different layers are usually incompatible, thus re-melting results in degraded properties, which are insufficient for most applications. Therefore, the aim of this work was to investigate the composition effects of polyethylene based formulations, containing polyamide as the main component, but also barrier layer materials like ethylene vinyl acetate and ethylene vinyl alcohol. The different formulations were melt blended, with or without compatibilisation, in a twin-screw extruder, where for selected formulations processing parameters and screw geometry were varied. The materials were further processed via injection moulding to retrieve universal test specimen for mechanical testing (tensile and impact tests). Further characterisation, via scanning electron microscopy or rheology (represented her by melt flow rate determination), was carried out to investigate the correlations between composition, morphology and properties. We found, that the morphology is formulation dependent, and, that it is possible to compatibilise such formulations by applying maleic anhydride grafted polyethylene, so that the blends properties were sufficient for application again. Also, the mechanisms of the compatibilisation and the resulting morphologies can be, besides some processing influences, related to the chemical compositions of the components and their possibilities of interaction. These findings can help in the mechanical recycling of multilayer film based on polyethylene.