MACHINERY | LABORATORY EXTRUDERS
work with multiple types of materials in one extruder, including PET, PE and PLA. Foamed and non-foamed sheets can be produced on the same line, even allowing for multilayer A/B/A sheet (where the A-layer is a non-foamed and the B-layer is a foamed material).
Chemical recycling Coperion is supplying a laboratory extrusion system to the Laboratory for Chemical Technology at Ghent University in Belgium, allowing it to carry out research and development into the chemical recycling of mixed plastic waste. The system, based on a ZSK 18 MegaLab twin
Above: Collin’s new combi-line will help Bischof + Klein develop and test new films
extruded along either the edge of the extruded PLA. Encapsulating PLA with edges of LDPE made it possible to offset PLA deficiencies – especially its low melt strength – that can affect performance. “Using LDPE edge encapsulation on our pilot
line, we have achieved speeds in excess of 1200 ft/ min (366 m/min) with PLA, against less than 600 ft/ min (183 m/min) with PLA alone,” said Ed Lincoln, vice president of extrusion sales at SAM North America. The high melt strength of LDPE has made it the most widely used polymer in extrusion coating.
Saving through foam Meaf Machines has added a Promix physical foam- ing installation to its in-house extruder test and demonstration line, which it says can help save on material costs. The set-up will allow customers to gain experi- ence with the equipment using their own polymer grades.
In film and sheet extrusion, raw materials typically account for 70% or more of production costs. Ways of reducing this include using more recycled material – such as regrind skeletal waste or bottle-flakes – or by using filler components such as calcium carbonate. Another way is by using foaming.
“Physical foaming offers significant material- saving potential for extrusion processes,” said Roald de Bruijne, sales manager at Meaf. Adding Promix equipment to the line can lead to density reductions of 5-30%, says Meaf. The process – which uses carbon dioxide or nitrogen as a blowing agent – can reduce the cost of plastic raw material by 20% compared to conventional packaging, due to the weight saving. The micro foam process offers high rigidity,
insulation and insensitivity to scratch marks, and a low energy consumption per kg. Processors can
56 FILM & SHEET EXTRUSION | September 2021
screw extruder, was designed specifically for chemical recycling of post-consumer waste. It has a throughput range of 1-10 kg/hr and includes a feeder and a vacuum unit. Chemical recycling is a potentially promising method for recycling plastic waste – especially packaging, as it can be hard to collect, sort and clean. Coperion says that its twin screw extruder technology is well suited to chemical recycling of plastics. Shredded or compacted post-consumer waste is added to the process section by the feeder, which leads to a homogeneous, devolatil- ised melt with a temperature of up to 350°C. Further materials, such as catalysts, can be added. In some cases, residual water or chlorides from PVC can be extracted via vacuum devolatilisation on the extruder’s process section. The ZSK twin screw extruder will be part of a new setup for chemical recycling at Ghent Univer- sity. It will be among several machines coupled to a vortex reactor – allowing molten plastic to flow directly into the reactor. Different technologies for the converting plastic waste into chemicals – such as catalytic pyrolysis and thermo-chemical process- ing (cracking) – may be applied. “We are proud to support Ghent University in their chemical recycling research,” said Jochen Schofer, manager for recycling and direct extrusion at Coperion. “We see it as a trailblazing process for reclaiming raw materials from mixed plastic. As soon as this recycling system is in operation at Ghent, it will be available to our customers for testing.”
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.collin-solutions.com �
www.sam-na.com �
www.nordson.com �
www.meaf.com �
www.coperion.com �
www.lct.ugent.be
www.filmandsheet.com
IMAGE: BISCHOFF + KLEIN
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