Professor Edward Kosior
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One year ago, almost to the day, I wrote an article talking about the four components poised to make or break brand owners鈥� recycling targets. I addressed the main roadblocks to recyclability and referred to the disconnect between the EU Green Deal and the EU Circular Economy Action Plan driving for all packaging in the EU to be reusable or recyclable by 2030, whilst navigating the European food safety regulations that are slowing industry鈥�s momentum to use recycled food-grade resins in food-contact packaging. Having recently attended the Plastics Recycling Show Europe (PRSE) in June, I can confirm this is still top of industry鈥檚 concerns.
In the meantime, in the U.S., EFSA鈥檚 U.S. counterpart, the FDA have given their 鈥淟etter of No Objection鈥� (LNO) to 14 companies in North America, Asia, and Europe to use their recycled resin products for food-contact packaging. It is interesting to note that despite these LNOs there is no information or publicity on applications of recycled food-grade Polypropylene (PP) resin being used in food-contact packaging.
I believe the key reason for this is the fact that PP is only just embarking on its recyclability journey. If we consider the most widely recycled polymers to date, PET and HDPE, their recycling journey was not an immediate overnight success either.
When we were first producing food-grade rPET (in the UK) there was considerable reluctance to using it in food-contact packaging. In fact, it required extensive trialing before it was adopted for standard production. The same process happened with food–grade recycled HDPE used in milk bottles. Now food-contact rPET and rHDPE do not even cause a ripple. rPP on the other hand has just started out on this journey.
Recycled Food-Grade PP鈥檚 First Step
PP accounts for more than 20 percent of global plastics production and food packaging is one of its primary products. In the U.S., PP is one of the most converted polymers with a market share of about 20 percent (in 2018), yet it is also one of the least recycled (15 percent in Europe and less than 5 percent in U.S.) mainly due to its extensive use in non-bottle packaging applications, such as cups, tubs, and trays.
To understand why recycled food-grade PP resin is still hesitant, even with an LNO from USFDA, we need only check PET and HDPE鈥檚 tentative first recycling steps. The reticence towards ensuring a new resin鈥檚 safety is wholly understandable. The hesitation comes from a lack of experience that this food-grade recycled material can be safely used in consumer food-contact packaging.
The challenge with rPP is that up until now it has not been possible to accurately differentiate between PP packaging that once contained non-food products from those that contained food. Consequently, current food-grade recycled PP has been limited to closed loop recycling, hand sorting or advanced recycling technology processes based on mass balance (which is not yet recognized as recycling in the EU).
Characterizing Residual Contamination Levels in rPP
NEXTLOOPP鈥檚 ongoing science-driven exploration to close the loop on post-consumer food-grade PP, is cause for reassurance. Addressing every roadblock along the way and deep-diving into the specific sorting and decontamination requirements for the recycling processes for PP, led the multi-participant project to run a major study to determine the residual contamination levels of post-consumer PP packaging, which up until now, have never been characterized.
The lack of data showing the misuse/mis-selection rate within PP feedstocks had meant there was no reliable way of defining the residual levels that could potentially migrate into food as well as understanding which molecules to target via decontamination processes.
听NEXTLOOPP鈥檚 study aimed to identify substances that might cause samples of rPP to be outliers from the expected input stream that could represent challenges to the final safety of the recycled plastics. One key aspect was to check whether the substances observed could potentially be genotoxic.
听This is a critical criterion for food safety evaluations given that the substances could be derived from the mis-selection of an item of non-food PP packaging, which is not necessarily a case of misuse.
听The Shape of the Pack
Despite being olefinic, the packaging format of consumer PP packaging reduces the chances of it being in a consumer-misuse scenario. A large proportion of PET packaging is relatively durable, with a tight closure, making it a container of choice when used for the storage of hazardous materials. Likewise, HDPE packaging is also in bottle form with a closure, meaning it, too, may be used in such a scenario.
PP food containers, on the other hand, are less likely to come in bottle form and much more likely to be pots, tubs, or trays with limited closure capability, making it a less likely candidate for containing hazardous substances in the first place and consumer misuse.
Contamination Levels in PP 100x Less than in PET
Characterizing the residues in post-consumer packaging that have been sorted into mono-polymer fractions was done by analyzing and testing multiple batches of food and non-food samples to see what molecules are present and if there are any areas of concern.
To achieve this our team of scientists worked on 20-ton batches of PP bales sourced from a UK-based materials recovery facility (MRF). Using automatic optical sorters to separate color fractions of natural (clear), white and colored articles, each color fraction was hand-sorted into articles from food applications and articles from non-food applications.
The analytical study involved 700 tests, representing approximately 17,500 different PP packs based on 25 significantly sized flakes per test. This was estimated to be a cross-sectional representation of 7 percent of the packs from the combination of batches of 260,000 packs.
Following this contamination study, NEXTLOOPP characterized the contamination levels in PP and concluded that they are in the order of 10x less than what we expect in HDPE milk bottles and 100x less than expected in PET. This is not surprising given the applications that select PP as the packaging material.
Challenging the Status Quo on FGrPP
This study marked a turning point in the NEXTLOOPP project, giving us the confidence to use our unique PPristineTMfood-grade rPP in food-contact packaging. The performance standards we have now developed will enable us to help organizations reach a high level of technical performance as well as commercial and legal confidence in the food-grade rPP they can include in food-contact packaging.
By deploying NEXTLOOPP鈥檚 expertise and technical backup, NEXTLOOPP aims to license the NEXTLOOPP technology to ensure that the resin standards can be fast-tracked into U.S.-produced rPP food-grade packaging.
Finding validated local solutions for the end of life of post-consumer food-grade, PP packaging has been the driving force behind NEXTLOOPP鈥�s participants, who continue to produce and trial a range of unique grades of high-quality food-grade recycled PP resins produced using Nextek鈥�s patented PPristine鈩� decontamination technology.
Proof in the Commercialized Trials
Eighteen of NEXTLOOPP鈥�s brand and converter participants have now finalized 55 commercialization trials using five PPristine鈩� resin grades; Natural food-grade IM, Natural food-grade, White food-grade, Mixed Color food-grade and non-food grade Mixed Color INRT and the results have been outstanding. As an example, trials using 30 percent of NEXTLOOPP鈥�s PPristine鈩� resins in both extrusion and thermoforming trays achieved product quality that is comparable with the virgin products with no changes in processing conditions.
Transforming Sorting
While the multi-participant project now fine-tunes the resin quality standards that are poised to become standard for food-grade recycled PP, recent trials conducted by NEXTLOOPP together with TOMRA, have confirmed a major breakthrough in the automatic sorting of food-grade PP packaging.
These sorting trials held in February, which combined TOMRA鈥�s near-infrared and visible wavelength spectrometry with the company鈥�s latest deep-learning technology GAINnext鈩�, achieved food-grade separation levels exceeding 97 percent in packaging applications.
This exciting development is an invaluable boost to the NEXTLOOPP project, as GAINnext鈩� has the potential to be rolled out to all PP packaging sorting facilities and will help produce valuable food-grade PP PCR streams. By providing a sorted food-grade PP PCR stream, GAINnext鈩� will enable the NEXTLOOPP decontamination process to be carried out in many more recycling operations globally.
Close to the Finish Line
Since launching in 2020, NEXTLOOPP鈥檚 53 participants across the plastics supply chain have steadily broken through most of the barriers to producing recycled food-grade polypropylene (FGrPP) from post-consumer waste.
听We are now looking forward to sharing our science-based findings and expertise with U.S. organizations to boost their confidence in using a recycled resin that will help the industry drastically reduce its carbon footprint and reach their recycled content targets, something we hope will give momentum to the European Food Safety regulators.