Abstract
In line with efforts to create a circular economy of plastics, recent EU legislation is strengthening plastic bottle recycling by ambitious separate collection targets and mandatory recycled content obligations. Furthermore, explicit design requirements on the caps of bottles and composite beverage packaging have been introduced. These caps are typically made of polyethylene or polypropylene and often contain additives such as slip agents and anti-statics. Commercially available bottle cap recyclates (BCRs) as well as specifically formulated model compounds were analyzed in terms of composition by means of infrared spectroscopy, differential scanning calorimetry, and high-performance liquid chromatography. Their composition was found to be heterogeneous due to polyolefin cross-contamination, directly reflecting the diversity of cap materials present in the market. Slip agent legacy additives originating from the initial use phase were found and quantified in both commercial and model cap recyclates. This highlights the opportunity for redesigning plastic bottle caps not only in response to regulatory requirements, but to pursue a more comprehensive strategy of product design for circularity. By including considerations of polymer resin and additive choice in cap manufacturing, more homogeneous waste streams could be derived from plastic bottle cap recycling, enabling recycling into more demanding and valuable applications.
Highlights
Plastic bottles made of polyethylene terephthalate (PET) are a good example of well-defined post-consumer plastic waste streams that are suitable for high-quality mechanical recycling [14]
The respective bands were absent in all virgin resins when spectra were recorded from the bulk via measuring the cross-section instead of the surface locations of plastic granules
In the current quest for higher recycling rates of plastics, it seems crucial to adopt a comprehensive approach on material composition and quality
Summary
Plastic packaging in particular [3,5] is in the focus when it comes to addressing the transition from linearity to circularity. Packaging is both the main application field for single-use plastics [12] and the biggest group among different post-consumer plastic waste fractions [5,13]. Plastic bottles made of polyethylene terephthalate (PET) are a good example of well-defined post-consumer plastic waste streams that are suitable for high-quality mechanical recycling [14]. The recycling schemes and processes for PET bottles have evolved to very high standards that allow for post-consumer recyclates to be reintroduced into new food contact applications [15].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
