A system has been developed to recycle waste plastic into customised compounds in one step, without intermediate cooling, according to the firms behind it, Erema and Coperion.
Waste material, including non-woven PP, PE edge trim or PA fibres, is cut, homogenised, heated, dried and buffered in the patented Erema cutter/compactor. The preheated material is plastified in a tangentially-connected single-screw extruder before being cleaned in a fully-automatic filter. The prepared melt then goes directly to the co-rotating Corema twin-screw extruder from Germany's Coperian.
A wide variety of additives, fillers and reinforcing agents can be added including 80% chalk, 70% talcum or 50% glass fibres.
“We made a conscious decision in favour of Coperion as a partner,” said Erema's co-CEO, Manfred Hackl. “This company has a wealth of experience in the production of compounds, and the twin-screw extruders are made in such a modular way that they can be adapted for any individual job. And the same applies to our recycling system.
“Together we are convinced that with this combined technology customers can take another step in the value added chain and turn waste into new products in an economic way.”
Corema systems are available for both smaller amounts of 300 kg/h and large amounts of up to 4 tonnes/h. Hackl continued: “We are of the opinion that Corema is the ideal system not only to process inexpensive mixed fractions such as PET/PE with additives, but also to produce a compound with 20% talcum out of PP non-woven waste, for example.”
PP/talcum compounds are used mainly for white household goods and in the automotive industry.
Dutch recycler Rodepa Plastics is one of the first operators of Corema. Rodepa's Mark Langenhof had noted increasing customer demand for filled recyclates and had decided to move into the compounding business. Langenhof decided that Corema fitted his requirements: “The recycled material is processed and filtered in the robust and proven cutter/compactor single-screw system.
“The clean melt then moves directly to the twin-screw unit which is available for a wide variety of compounding tasks. All in all, you can expect outstanding energy efficiency from this process.”
Currently Rodepa is mainly processing production PP for injection moulding applications and LDPE for film applications.