Coperion delivers visionary closed-loop multi-layer film recycling solution

08 Apr 2020 --- Coperion has developed a closed-loop concept for the production of flexible multi-layer film in which up to 100 percent of production waste can be re-processed and fed back into the production process. The concept overcomes the long-posed challenge of recycling multi-layer films. The compounding and extrusion specialist is now offering the innovative recycling system, including bulk material handling, high-accuracy feeding from Coperion K-Tron and, at the heart of the system, a ZSK Mc18 twin screw extruder.

Recycling multi-layer film has long posed a challenge since such films can only be reclaimed in very complicated ways and not without residues. Recent innovation has centered on mono-material solutions, which are more easily recycled, such as Mondi-Unilever’s polypropylene (PP) mono-material pouch for the Knorr dry soup powder range and Berry bpi Group’s X-Enviro laminate range.

Click to EnlargeWithin the ZSK Mc¹⁸ twin screw extruder, shredded production waste is processed such that it can be added back into the multi-layer film production process at consistently high end product quality.Meanwhile, the development of chemical recycling infrastructure is on the rise. Chemical recycling uses thermochemical processes to transform plastic waste, including multi-layer films, into pyrolysis oil. This secondary raw material then serves as feedstock for the chemical industry to produce plastic for various purposes, such as packaging. In December, recycling and recovery organization Citeo joined forces with Nestlé and Mars, international energy company Total and plastic recycling technology provider Recycling Technologies to develop an industrial chemical recycling industry in France. However, some concerns remain that chemical recycling is too energy-intensive to offer a long-term recycling solution.

Now, however, Coperion has developed a closed-loop solution in which up to 100 percent of multi-layer film production waste can be re-processed and fed back into the production process in a closed-loop.

In Coperion’s system, multi-layer film waste resulting during the production process is shredded as a first step before it is fed into the ZSK extruder via pneumatic conveying and highly accurate feeding from Coperion K-Tron. There, the material is homogenized and devolatilized with very high intensity in the co-rotating ZSK Mc18 twin screw extruder.

Click to EnlargeWith Coperion’s innovative closed-loop approach, production waste resulting from multi-layer film production can be re-added and re-processed within the manufacturing process at a rate of up to 100 percent.Within the extruder, dispersion and devolatilization performance are crucial to end product quality – with gentle product handling and high-quality mixing behavior even at very high throughput rates, achieving consistently high product quality.

Following homogenization in the ZSK extruder, in the closed-loop concept, the recycled material is added back into the multi-layer film production process; with no quality loss and the proportion of added recyclate is very high. Multi-layer film manufacturing can, therefore, take place sustainably, highly efficiently and resource-friendly with the aid of advanced technologies, Coperion indicates.

“Sustainability is becoming more and more important, and the topic of the circular economy is moving further into the foreground for companies – and that is much more so for multi-layer film producers,” notes Peter von Hoffmann, General Manager of Business Unit Engineering Plastics & Special Applications at Coperion.

“We’re proud that, with our years of process know-how and our visionary technological solutions, we can contribute to a promising, forward-looking and sustainable closed-loop approach,” von Hoffmann concludes.

By Joshua Poole

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