One of the EU’s ambitious goals is to ensure all plastic packaging is reusable or recyclable by 2030. However, achieving higher recycling rates, particularly in flexible multilayer food packaging, is challenging due to the combination of diverse materials. This highlights the importance of designing for recyclability and exploring alternative barrier solutions. In this study, several types of coatings, such as ORMOCER^® (Fraunhofer-ISC, Würzburg, Germany) Michem^® Flex B3513 (Michelman International Belgium SRL, Aubange, Belgium), and PVOH (Kuraray Europe GmbH, Frankfurt am Main, Germany), are applied on different polypropylene substrates, including cast PP (CPP70), SiOx, and AlOx-coated PP films. The effect of double coating and optimized curing conditions of ORMOCER^® on the oxygen permeability of CPP70 was also investigated. The results showed significant improvements in the barrier properties of PP/SiOx and OPP/AlOx films, and OTR values less than 0.1 cm³/m²·d·bar were achieved. It was also found that ORMOCER^® and Michem^® Flex B3513 could enhance the oxygen barrier property of CPP70 and the OTR value reduced by a factor of 88 and 551, respectively.

Flexible packaging often consists of multilayer films that combine different materials to achieve high barrier performance, but these structures are incompatible with current recycling technologies. Polyolefins such as polypropylene (PP) offer more recyclable alternatives but require additional oxygen-barrier materials that do not compromise recyclability. This study investigates the influence of ethylene vinyl alcohol (EVOH), Ormocer^® barrier coating, and PP labels with different adhesives on PP recyclability. Recyclates were produced using twin-screw extruder to simulate the recycling process and then injection-molding to make tensile test specimens. Mechanical properties, melt flow rate (MFR), oxygen induction time (OIT), and odor were evaluated. Findings showed that low label content (5–12.5%) has minimal impact on recyclate quality. The addition of 10% EVOH increased the elastic modulus of PP granulate and cast-PP (cPP) film by 26% and 14%, respectively, and improved oxidation stability by 9%, while reducing cPP film impact strength by 77%. Ormocer^® decreased mechanical performance, particularly elongation at break (−18%), likely due to defect-inducing particles, but had limited influence on MFR. Labels and Ormocer^® also introduced odor variations. Overall, the findings indicate that EVOH up to 10% and labels up to 12.5% yield promising results, providing guidance for designing recyclable, monomaterial packaging.