Creating New from Used: Which Technologies Are Key for High-Efficiency Plastics Recycling

Over 180 participants from 25 nations accepted the invitation from Coperion and Herbold Meckesheim to attend the Recycling Days² in the newly opened Recycling Innovation Center in Weingarten, Germany, on November 6 and 7, 2024. In keeping with the theme of “Experience A New Dimension of Plastics Recycling,” the two-day conference featured a variety of presentations and live demonstrations, allowing participants to gain insights into various technologies designed to enhance the efficiency of the plastics recycling process. 

Internal and external experts from the industry, including researchers, shared insights on how the right equipment can save resources and costs without compromising the quality of the recycled compound. Practical examples from successful recycling plants also significantly enhanced understanding of the topic.

Achim Ebel, Head of Sales at Herbold Meckesheim, and Kürşat Başdemir, Company's Founder and Project Director at Ekosistem Ltd., presented the latest advancements in Herbold washing lines, focusing on the impact of water treatment on the quality of the recycled compound. Martin Müller, CEO at Polymetrix, and Sabine Schönfeld, Sales Manager at Coperion, gave a joint presentation on a bottle-to-bottle recycling plant. This system of Indian preform and plastic packaging manufacturer Magpet Polymer Pvt Ltd. produces rPET granulate approved for direct food contact by both the European Food Safety Administration (EFSA) and the U.S. Food and Drug Administration (FDA). Furthermore, it is brand owner approved. 

Spotlight on extrusion: The impact of various technologies on the process

Coperion leaders Frank Mack, Head of Process Technology Engineering Plastics, and Jochen Schofer, Head of Sales Recycling, presented a lecture on the range of possible extruder types for plastics recycling, demonstrating how the choice of extruder technology can impact both the overall process efficiency as well as end product quality.  

One unique feature of twin screw extruders is their especially high output capacity. Coperion developed the ZS-B MEGAfeed to complement its ZSK twin screw extruders. This side feeder compresses recyclates with primarily very low bulk density, such as flakes and fibers, enabling them to be introduced into the recycling extruder in large quantities while leveraging the equipment’s optimal performance. 

A further advantage of twin screw extruders touched upon by Mack and Schofer is their flexible configuration, adaptable to a variety of recycling applications. This flexibility makes it easy to incorporate additives, glass fibers, and fillers commonly needed in high-value recompounds into the process. Coperion ZSK recycling extruders feature a modular design: The co-rotating twin screws are comprised of various screw elements that perform specific tasks to achieve the desired effects. Depending on the recycling application, intensive mixing, plastification, or shearing can be achieved. Moreover, the continuous surface renewal caused by the rotation of the twin screws results in an especially high devolatilization capacity in this type of extruder. 

Live demonstrations: Insights into the details 

On both days of the conference, guests could witness the newest developments in action during live demonstrations in the Recycling Innovation Center. The added value of individual technologies was demonstrated on running systems, along with their impacts on the entire recycling process. 

The processing of PCR film flakes with a bulk density of 30 kg/m³ into rPE compounds was demonstrated live during the event. The interplay of the ARW discharge agitator and the Smart Weigh Belt (SWB) feeder provided even feeding of fluffy and voluminous raw materials. The ZS-B MEGAfeed side feeder compacted the film flakes so they could be fed into the ZSK 58 Mc¹⁸ recycling extruder at a very high throughput to be compounded. The melt was then filtered and processed into rPE granulate in an underwater pelletizer.  

Attendees had the opportunity to see the benefits of Coperion’s twin screw extruders’ self-cleaning screw profiles and mixing properties by observing an STS 25 twin screw extruder in operation. Fillers and reinforcing materials were added to the recyclate in varying quantities, demonstrating how quickly recipe changes can be implemented on Coperion extruders without cleaning effort or product loss. 

Attendees asked a range of questions following the presentations and engaged in lively discussions during breaks and live demonstrations, illustrating the need for information in the field of plastics recycling. Participants repeatedly expressed amazement at the wide range of opportunities available, even within their own companies, to increase the efficiency of plastics recycling, with short-term ROI and increased quality consistency.

“The Recycling Days² exceeded our expectations. The interest and the atmosphere were both outstanding. These two days made it clear that we are on the right track and are sustainably driving the rate of plastics recycling forward as we continue to make adjustments to further increase the efficiency of the process and the attractiveness of plastics recycling,“ said Massimo Serapioni, General Manager of the Recycling Business Unit at Coperion.