Recycling offcuts, start-up rolls and other production waste has been part of the Polifilm Group's daily business for many years. However, the internationally positioned expert for extrusion and protective film solutions also knows about the limits of the process. Not every type of film can be recycled and returned to every application as a recyclate. The challenges range from added additives to impurities. The result: waste in the form of unused film scrap.
In addition, the recovery of recyclate requires large amounts of energy and storage capacity. Another cost and environmental factor that should not be underestimated.
A state of affairs that Polifilm was not satisfied with: "Being limited in the products we recycle and disposing of production waste instead of recycling it is the opposite of economical for us. Even more, we are aware of our responsibility. We are aware of the impact we have on the environment and society," says Michael Koll, recycling specialist at POLIFILM. That is why Polifilm has set itself the goal of increasing the proportion of recycled material in its own products, using its own resources, and thus helping to close loops.
Increasing the proportion of recyclate: How this works in plastics extrusion
Plastics producers are under increasing pressure to increase the proportion of their recyclate. In the process, they are often caught between the conflicting priorities of sustainability and economic efficiency. The Reifenhäuser Group manufactures highly flexible extrusion lines and robust components as a solution to this conflict. The lines are capable of converting a wide range of recycling raw materials reliably.
tonnes p.a. recyclate were processed at Polifilm in 2019
tonnes p.a. recyclate were processed at Polifilm in 2019.
times the quantity of processed recyclate by 2027.
"As a company, we focus on optimization in everything we do, and that should also be the case with recycling," says Koll, who is responsible for the Recycling business unit at POLIFILM. The experts around Koll do research, tinker with different film layers, add auxiliary materials in the recycling process. But the approaches brought no solution that improves the recyclability of the critical material and at the same time meets Polifilm's quality requirements.
In the end, a contact with Reifenhäuser came about quite by chance. Polifilm's recycling team described the challenge - Reifenhäuser's blown film specialists presented their EVO Fusion twin-screw technology. The technology allows manufacturers to process highly contaminated and inhomogeneous recyclates. "Normally, low-quality recyclate can only be mixed to a small extent with virgin material or other recyclate of higher quality on a mono-screw," Kilian Sieling, Area Sales Manager at Reifenhäuser. "However, our twin-screw technology achieves a high degree of degassing and better mixing. This means manufacturers are less dependent on the quality of the recyclate."
Three benefits of fluff-to-film:
In addition, the technology allows the direct processing of film residue and film scrap, known as fluff, to produce new film. "There is a significant difference between the fluff-to-film process and previous recycling processes, where recyclate is first melted and then granulated," explains Kilian Sieling. “Our EEVO Fusion twin-screw technology
allows us to simply skip the re-granulation stage." From Polifilm's point of view, this is a major benefit: "We save a very energy-intensive process step." emphasizes Koll. "Here, we're talking about significant economic benefits in view of the current rises in energy prices – and we save substantially on carbon emissions.”
In the fluff-to-film process, new film can be made in a single step from film scrap, known as fluff, without the need for granulation and pre-drying. The secret to the success of the EVO Fusion twin-screw technology is its high degassing performance and mixing function.
Added to that, the process has a positive impact on the quality of the film produced, explains Koll. In the regranulation process, the recyclate is shredded, heated, and cooled. In the following production process, the granules are then reheated and recooled. On the other hand, the fluff-to-film process shreds the recyclate cold and only heats it in the production process when it is extruded directly to film. "This process protects the polymer structure and improves the quality of the film," explains Koll.
Polifilm was already convinced by the concept in theory. The next step was a series of practical trials at the Reifenhäuser Technology Center in Troisdorf. Experts from Polifilm, Reifenhäuser and a manufacturer of plastic film shredders collaborated to find the right shred size and the optimized line settings.
A one-week endurance test will then be carried out in the fall of 2021. This will examine, for example, the extent to which contamination is noticeable during operation. The test showed that the film obtained is of convincing quality even with critical starting material and can be processed further without any problems. "This was a great success for all of us and a great team effort," said Kilian Sieling from Reifenhäuser. This is also confirmed by Polifilm's recycling expert Koll: "We fit together well: We are both medium-sized companies who are pragmatic and 'down-to-earth' in a positive sense, who simply test things and deal with each other openly in order to make progress in this important task - namely, closing the loops and reducing energy consumption."
For more than 8 years, Michael Koll has held various roles within the POLIFILM Group and previously worked as an audit manager and tax consultant at the auditing firm BDO.
Currently, a new production hall is still under construction at the Weissandt-Gölzau site so that recycling and extrusion can take place in close proximity. By the end of 2022 at the earliest, Polifilm will then start recycling film scrap that were previously of limited use, which is also more energy-efficient than the classic process. Thus, the fluff-to-film process is started on an industrial scale for the first time.