An innovative polypropylene (PP) lidding film to replace foil lidding could boost the recyclability of PP containers. PKN spoke to Prof Edward Kosior of Nextloopp, and Stijn Quintyn of MCC Verstraete, about the development.
Accelerating recycling capacity is increasingly reaching the top of climate change agendas of late, and rightly so. Of course, it will take multiple strategies to achieve this, from redesigning packaging for simplified recycling to escalating the Plastic Packaging Tax in Europe, not to mention the initiatives that are already successfully transforming the sector.
The majority of plastics can now be economically and efficiently recycled if they are collected, sorted and cleaned, which is why Nextloopp’s 53-strong consortium have been running real-world, high-performance sorting and decontamination trials to achieve this,” Prof Ed Kosior says.
Beyond Foil
It was during one such trial last year that the team found fragments of aluminium foil present in the otherwise clean rPP recyclates. On further investigation it was found that even the smallest remnants of foil on the likes of yoghurt pots disrupted the melt filtration of the recyclates by blocking the melt filters that effectively stopped the extrusion recycling process.
“Aluminium die-cut lidding that is heat-sealed to PP, PS and PET containers is a common form of packaging and while Nextloopp had already identified adhesives, inks and pigments as key challenges in packaging design, we have now added foil lids to the list,” Kosior says.
One of Nextloopp’s participants, label expert MCC Verstraete, took on the foil lid challenge and explored a number of possible solutions.
As Stijn Quintyn, MCC’s business development manager explains, a foil-lidded container presents two key challenges, one being two separate materials in one pack and the other is the remnants of foil particles that remain on the lid once it has been torn off. This alone can result in perfectly good rPP tubs ending up in the residue stream rather than being sorted for recycling.
Innovative Polypropylene lids
MCC introduced a polypropylene heat-sealable lidding solution that didn’t require any heat seal lacquer with good results. The company found that by using full mono PP packaging a 14 per cent higher yield was achieved during the sorting phase.
This PP lid, called SealPPeel, optimises both sortability and recyclability. Next to the obvious sustainability improvements, there are also benefits for consumers.
“While aluminium seals often get damaged during transport, the SealPPeel lids are twice as puncture-resistant compared with thinner aluminium seals. From the consumer’s perspective it is practical as the PP lid is easy to open and microwavable; it is also visually appealing and provides higher graphic quality to improve strong branding cues,” Quintyn says.
Competitive solutions
Quintyn acknowledges that change is always difficult to implement, however, the first SealPPeel lids are already hitting the shelves and brand owner reaction has been positive. He believes that the upcoming regulatory changes are an additional incentive to switch to mono-material PP packaging.
“After close to four years of intense collaboration the Nextloopp participants are now breaking down the final barriers to producing food-grade recycled PP from post-consumer packaging into new circular economy products,” Kosior says. He notes that boosting the production of recycled food-grade PP resin is a major step towards stimulating growth in the sector and creating a market where sustainable solutions will become competitive with, and a replacement for, virgin polymers.
This article was first published in the May-June 2024 print issue of PKN Packaging News, p22.
