Each of the 70 extrusion machines at Polifilm is reconfigured several times a day, the scrap material is collected and sorted according to type and colour before it goes to a recycling machine
One of the biggest producers of extruded polyethylene (PE) film in Europe is set to install its sixth central system for the in-house production of recycled pellets for bin liners.
Polifilm Extrusion GmbH, based in Germany, has a production capacity of 220,000 tonnes per year from more than 70 extrusion plants. It uses the scrap material from the reconfiguration of each line to produce the pellets in a closed-loop process. It says the planned installation of an additional central recycling system from EREMA is crucial from both a cost saving and sustainability perspective.
“With our recycling machines we not only realise the waste-free factory, we also work very economically,” said Reinhard Händel, Project Manager at Polifilm “With a production capacity of 220,000 tonnes of film per year, reconfiguration and start-up scrap is inevitable – and using your own recycling lines pays off.
“If you work properly with recycling materials instead of virgin you can save around 30 percent for every tonne of material processed and that corresponds to roughly 300 to 500 Euros (approx. £240 - £400 GBP),” he explained. “Our recycling facilities work 24/7, just like our film plants.”
In addition to technical films, packaging films, construction and agricultural films and stretch films, which are produced in cast or blown film extrusion processes, Polifilm produces 80 different types of recycled pellets. The company operates six central recycling lines in total – besides edge trim refeeding on every plant – working in four shifts and producing 25,000 tonnes of recycled pellets every year.
The company is now looking to install an additional EREMA system, to complement the ‘T’ systems for non-printed and ‘TVE plus’ systems for printed film scrap it currently operates.
The systems work without stuffing units and use the equipment’s cutter/compactor to guarantee constant material flow. This is achieved, says EREMA, with the combination of a preconditioning unit with the recycling extruder, which allows films of varying thicknesses to be cut, heated and compacted to a uniform bulk density of around 350 kg/m³. By being compacted this way, the material can be added continuously and pulsation and process fluctuations are ruled out. Another benefit of the cutter/compactor, EREMA says, is the preheating of the materials, which requires less energy intake for plastification inside the extruder and therefore thermomechanical stress on the polymer is minimised.
The cutter/compactor also carries out the degassing process. This is because moisture deposits on the film scrap can occur from time to time due to fluctuations in temperature and air humidity when in-house waste is kept in storage.