Challenge overcome in tray and film recycling

In Europe and elsewhere, the pressure to recycle more is increasing, as Dr. Michael Gotsche, Managing Director at Krones Recycling, explains: “Legislators demand higher proportions of recycled materials, trading companies set themselves ambitious sustainability targets and consumers expect transparency.” So there is meanwhile a growing awareness of the need to recycle not just PET bottles but to also feed more complex packaging like films or PET trays back into the plastics loop. 

The key to accomplishing this lies in state-of-the-art recycling technologies. But that is precisely where several challenges have so far been looming: PET trays are often made of multilayer materials, contain barrier coatings, and/or are brittle or heavily soiled whereas flexible packaging is lightweight, thin and frequently consists of a combination of different materials that are difficult to separate. All of that leads to lower yields and poor-quality recyclate and means a large amount of these plastics are used for energy recovery instead of being recycled. 

Gentle processing of single- and multilayer PET trays

With processes that have been specifically modified for handling films and PET trays, Krones Recycling has now shown that there is in fact another way, thus closing the loop for these plastics, too. 

As a partner in the “Pac2Pac” project, the company has already been able to demonstrate that its washing technology is also suitable for single- and multilayer PET trays specifically. The project provides innovative proof of how PET packages from Swiss plastics collection bags can be recycled into new packaging, which constitutes a big step forward on our way to a circular economy. The MetaPure Compact, a newly developed washing-module configuration, has now been fine-tuned to even better meet these materials’ specific needs.

A particularly gentle washing process for treating PET trays was one of the exhibits that the company presented at K 2025 in Düsseldorf, Germany. The ingenious bit about it is this: Thanks to the continuous process developed by Krones Recycling, intermediate steps like interim storage or additional drying of the flakes are no longer necessary. Devices that use high shear forces can therefore be dispensed with, which results in minimised production of fine particles while the patented hot-washing process ensures washing results of a consistently high quality. 

This process is suitable for both single-layer and multilayer materials. Conserving resources is also a major priority in the industry, which is why the technology used in the MetaPure Compact washing module scores highly in terms of optimally efficient use of energy and low water consumption, with the HydroCircle water cascade system playing a crucial part here.

Change of direction in film recycling

A new concept has also been developed for flexible packaging, mostly films made of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) or polypropylene (PP). The process, which was likewise presented for the first time at K 2025, is as usual based on hot washing in caustic, which produces clearly better results than those obtained with cold washing. Hot washing removes even the most obstinate kinds of contamination like adhesives, printing or organic residues, thus ensuring top-notch flake quality. 

We’ve developed a concept specifically tailored to film recycling, which uses a hot-washing process and still ensures a large throughput. That’s very important because it makes sure that film recycling is commercially viable. Dr. Michael GotscheManaging Director at Krones Recycling

A special highlight is the horizontal intensive washer which was developed specifically for this new concept. It ensures consistently high throughputs for lightweight and clingy materials like films, which frequently tend to bridge in vertical processes. Bridging here refers to a phenomenon where the material forms a kind of unyielding arch above the discharge aperture. Such a blockage significantly impedes an efficient material flow. 

The new solution features horizontal material transport and a lateral discharge. That makes for an even flake distribution and prevents blockages, thus keeping the process stable and resulting in optimum washing conditions, fewer stops and a consistently high throughput – ideal preconditions for challenging film-washing processes. 

This innovation is Krones Recycling’s answer to the growing demand for fit-for-purpose film-recycling technologies and enables the company’s customers to put in place an efficient and commercially viable process for this complex material flow, too. 

Closing the loop

The two innovations from Krones Recycling clearly show one thing: With the right technologies, even complex flows of plastics can be efficiently turned into top-quality recyclates. The company’s concepts not only enable further valuable materials to be fed back into the plastics loop. They also meet the ever-more-stringent requirements posed for quality, sustainability and cost-efficiency. They are thus vitally contributing towards establishing genuine circularity for all types of plastic.