MATERIALS / RECYCLING PETplanet Insider Vol. 25 No. 01+02/24 www.petpla.net 12 Starting with the end in mind for sustainable plastics packaging Shifting focus based on an article by Andrea Smith, Avient Increasing the amount of rPET can affect the processability, quality, and food safety of packaging. During the recycling of PET, it undergoes several remelting processes, which can cause thermal degradation and side reactions, resulting in rPET that is of a lower quality than virgin PET. This article will discuss the latest challenges and efforts from Avient to improve additives’ performance through recycling and design technologies with circularity in mind while maintaining functional performance. Today’s challenges Additives are added to PET to provide many functional advantages that can be particularly beneficial when using and processing rPET. However, as PET is recycled, it becomes increasingly important that these additives are designed to remain helpful and not adversely affect the quality, safety, and processability of rPET during the recycling process. This concept is of greater significance in closed-loop recycling systems, which are commonly used across Europe. Any negative impact from an additive could be enhanced due to the potential for accumulation in the closedloop system. Accumulation-related risks could be of particular concern, especially regarding regulatory or food safety. The accumulation of additives in recycling processes can lead to two potential issues. The first one is related to manufacturing and processability. For example, anthranilamide (ATA) based acetaldehyde (AA) scavengers are problematic due to high levels of sublimation. This issue manifests as deposition on the surface of the moulds in an injection moulding process, leading to downtime for cleaning the moulds, reducing efficiency and throughput. Deposition also occurs during the solid-state polymerisation (SSP) stage in the rPET manufacturing process when high levels of sublimation cause deposition on equipment, again leading to downtime for cleaning and reduced efficiency. If the levels of ATA in rPET keep accumulating, the processing issues related to ATA will also increase. The second issue is of higher concern and relates to regulatory compliance; the accumulation of ATAbased AA scavengers increases the risk of exceeding regulatory migration limits of ATA. This risk is well known and understood. However, when using ATA, there is a possibility of side reactions forming non-intentionally added substances (NIAS) components. These compounds also tend to accumulate over time despite being present at minimal levels and being undetectable until recently. As technology advances, the detection limits on analytical equipment have lowered, revealing the increasing concentration of these compounds due to the accumulation effect. This issue is now quickly becoming a concern for ATAbased products. Starting from September 2022, regulatory amendments have been imposed by Commission Regulation (EU) No 2020/1245 on Commission Regulation (EU) No 10/2011 regarding primary aromatic amines (PAAs). These compounds are present at minimal levels in PET-containing ATA-based scavengers and can now be detected by modern analytical devices. To remain compliant with the new regulations, it is necessary to provide additional toxicology data and migration testing for PAAs in PET articles containing ATA. PAAs are the first in a fast-growing list of other compounds detected in ATA-containing articles. Additional toxicology data and migration testing are crucial for these products to remain compliant. However, there is a significant risk of non-compliance that could result in a withdrawal of these products from the market in the future. Developing a solution To tackle today’s sustainability challenges, simulating the mechanical recycling process is necessary to design new additive technologies. Standard testing protocols at the European PET Bottle Platform (EPBP) and the Association of Plastic Recyclers (APR) are based upon one full recycle loop. However, as the use of rPET increases, the impact of two or more recycle loops is becoming increasingly significant. Therefore, it is more realistic to screen additive performance through at least two
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