Recycling multi-layer film, even production waste, has long posed a challenge. Such films require special treatment and the resulting residues remain an issue.
Coperion GmbH, the German compounding and extrusion systems suppliers, has now come up with a solution. The company has developed a closed-loop concept for the production of flexible multi-layer film, which, says Coperion, allows up to 100% of multi-layer film production waste to be re-processed and fed back into the production process.
“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,” said Peter von Hoffmann, general manager of the business unit Engineering Plastics & Special Applications at Coperion, explaining the reason for the development of the new closed-loop solution.
The recycling system comprises a pneumatic conveying system for bulk material handling, a Coperion K-Tron feeder, and a ZSK Mc18 twin screw extruder. Multi-layer film production waste is shredded before being fed into the ZSK extruder via the Coperion K-Tron feeder, where the material is homogenised and devolatilised. The system demonstrates very good mixing behaviour, achieving high throughput rates, and a consistently high product quality.
Following homogenisation in the ZSK extruder, the recycled material is added back into the multi-layer film production process with no quality loss. The proportion of added recyclate is ‘very high’, said Coperion, who called the new configuration a ‘promising, forward-looking and sustainable closed-loop approach’.