The problem of persistent odours in plastic recyclate is being addressed by recycling technology group Erema with its new ReFresher system. The ReFresher was launched at K 2016 and will be among the technology shown by Erema on Stand B68 at the Plastics Recycling Show Europe on 29-30 March.
See the PRS Europe website for information on all exhibitors at the event, which is organised by Crain Communications, publisher of Plastics News Europe.
"We recognised the potential of continuously increasing packaging waste early on and worked intensively on finding a technical solution for the odour issue,” said Manfred Hackl, CEO of Austria-based Erema. “With the ReFresher we offer recyclers and producers the edge in terms of quality to establish themselves in the marketplace with odourless recyclates from household waste."
The ReFresher eliminates odours caused by migrated substances on the waste plastic, which include food contamination, detergent residues and cosmetics. It operates downstream of the extrusion process, using warm, dry air to keep the recyclate granules at the required temperature at which volatile materials can be discharged.
But the process of getting rid of odours starts earlier with Erema's TVEplus technology, the company's core technology for reprocessing post-consumer plastic waste from packaging and other sources. Erema says its Intarema TVEplus prevents unpleasant odours from developing in the course of the extrusion process.
“In conventional processes these develop for example through cellulose contamination such as wood or paper which burn during extrusion and transfer the smell to the plastic. The interplay of the preconditioning unit, Airflush technology, low melt temperature, efficient filtration and several degassing steps ensures that the cellulose particles are separated from the plastic,” said the company.
Clemens Kitzberger, business development manager for the post-consumer sector at Erema, said: "At the end of the extrusion process what we have in our hands is high-quality recyclate which is already suitable for many applications. And here I am referring to extrusion products such as pipes or film in the waste management or construction industry.
The Airflush pre-conditioning technology eliminates odour-causing contamination on the surface of the input material, but also expels some of the migrated substances before the start of extrusion. The long residence time in the pre-conditioning unit means the ground material particles are completely heated and can be melted quickly and gently in the extruder.
Erema says that up to 70% of odours can be removed this way, depending on the input material and the migrating substances involved.
“The odour caused by migrated substances, however, is more stubborn,” said Kitzberger. “End products such as plastic parts in cars or in the home call for an additional recycling step to neutralise the odour. And this is exactly what we developed the ReFresher for."
The recyclates are transported from the extruder to the fully insulated ReFresher at a high temperature, which means only minimal energy has to be used to neutralize the remaining odours.
Erema is targeting the ReFresher unit at high-end recycled products, such as applications in the automotive sector. It is available in various expansion stages depending on the end application.
The company also offers a mobile ReFresher as an additional service for on-site trials at the customer's facility to allow optimisation for the requirements of the end product.
“The investment is thus designed to meet the exact odour requirements of the desired end application,” said Erema.