Recycling of Polymer-Based Multilayer Packaging: A Review

Abstract

Abstract:Polymer-based multilayer packaging materials are commonly used in order to combine the respective performance of different polymers. By this approach, the tailored functionality of packaging concepts is created to sufficiently protect sensitive food products and thus obtain extended shelf life. However, because of their poor recyclability, most multilayers are usually incinerated or landfilled, counteracting the efforts towards a circular economy and crude oil independency. This review depicts the current state of the European multilayer packaging market and sketches the current end-of-life situation of postconsumer multilayer packaging waste in Germany. In the main section, a general overview of the state of research about material recycling of different multilayer packaging systems is provided. It is divided into two subsections, whereby one describes methods to achieve a separation of the different components, either by delamination or the selective dissolution-reprecipitation technique, and the other describes methods to achieve recycling by compatibilization of nonmiscible polymer types. While compatibilization methods and the technique of dissolution-reprecipitation are already extensively studied, the delamination of packaging has not been investigated systematically. All the presented options are able to recycle multilayer packaging, but also have drawbacks like a limited scope or a high expenditure of energy.

Land use mediated GHG emissions and spillovers from increased consumption of bioplastics

“…In other countries, incineration with energy recovery offers sustainability gains due to electricity generation (Philp et al 2013). Recycling is usually the preferred option for plastic disposal but is often hampered by technical and logistic barriers (Kaiser et al 2017); these are however lower for drop-in products, which can enter existing plastic recycling infrastructure (Philp et al 2013). Although highly context-dependent, end-oflife options are energy intensive, delivering increased emissions throughout life cycles of plastic products.…”

Multilayer packaging: Advances in preparation techniques and emerging food applications

“…Multilayer packaging is an emerging technique that amalgamates the unique functionalities of various polymers with the aim of developing a package with improved performance in terms of improved protection and durability (Kaiser, Schmid, & Schlummer, 2017). In most cases, it is impossible for a single monolayer of polymer to meet all requirements of food packaging, including containment (strength and sealability), protection/preservation (moisture, gas, light, flavor/odor barrier), machinability (tensile strength, softening, slip, rigidity, pliability, and heat resistance), promotion, and convenience, while ensuring cost‐effectiveness and adhering to all aspects of food safety (Kaiser et al., 2017). Thus, the rationale behind the manufacture of multilayer packaging is to develop a single packing structure that possesses multiple functional properties in order to meet all the complex functional requirements of packaging.…”

“…Over the years, with advantages in terms of flexibility, cost affordability, ease of processing, convenience in handling, and functionality, the usage of polymers has found numerous applications in the field of food packaging (Kaiser et al., 2017). Polymers are the most preferred material for developing an active packaging system because of their ability to act as an ideal carrier for several active agents.…”

“…Although multilayer films are mainly used for their potential functional and barrier properties, the recycling process of these composite structures is quite difficult, requiring a cautious analysis of the sustainability aspect before its usage. Most multilayer packages are either incinerated or landfilled (Kaiser et al., 2017). This poses a serious threat to the environment and health.…”

“…In case of immiscible blends, varying properties of interlayers will complicate the process. Thus, for improving the blend process, different unit operations are performed to improve the compatibility and to make them miscible through the addition of chemical molecules exhibiting interfacial activity in case of heterogenous polymeric blends (Kaiser et al., 2017). The most commonly used biodegradable polymers for multilayer packaging films include polylactic acid (PLA), poly‐butylene adipate‐co‐terephthalate (PBAT) and polycaprolactone (PCL) that undergoed hydrolytic breakdown and get degraded within a week (Scaffaro, Maio, Sutera, Gulino, & Morreale, 2019).…”