machinery feature | Recycling & granulators
high quality, clean material for further processing. The company says that it can separate large amounts of post-consumer laminated plastic packaging from adhesive labels quickly and efficiently. Large amounts of packaging waste is relatively
clean, but difficult to recycle because it includes paper labels, which are often attached with strong adhesives. The usual method of recycling such waste is to granulate it and reprocess it in an extruder. But this requires a lot of melt filtration and frequent changes of melt filters. It may be possible to remove the labels by washing the packaging, but this requires the use of hot water, which consumes energy. Another alternative – using solvents – also introduces extra cost. Pallmann decided to develop the industrial equiva-
lent of some basic methods that are used in developing countries – where labels are often removed by vigorous manual brushing them off manually. In the Hydrofiner, a large amount of waste is
Bühler’s integrated optical sorting station (OSS) is an integrated system that includes pneumatic conveyors, pre-condition- ers and ancillary equip- ment
intensively rubbed between two surfaces, with a small amount of water. The material rubs mostly against itself, rather than the metal surfaces of the machine. The labels and glue are separated and removed, and the packaging is reduced to flake. The process is based on two discs – a rotor and a
stator – with material being fed to the centre via an auger, then moving to the outside through pairs of intermeshing teeth. The time the material spends between the discs can be altered by changing the speed of the rotor and by adjusting the amount of water. The water is injected at three separate locations to provide increased precision, and is recycled back into the system after use. The Hydrofiner has a throughput up to 1800kg/hour of packaging waste. It is modular in construction, and can fit into a 20- or 40-ft container for ease of transport and assembly. The company has already sold two systems.
Dissolving PLA
The Fraunhofer Institute for Process Engineering and Packaging (IVV) has developed three new variants of its Creasolv process – including a method for recycling PLA. Creasolv is a solvent-based process that selec-
tively recovers a specific plastic from a mixture of materials. IVV says that it has developed a way of separating pure PLA, PLA-containing fractions, PLA composites and blends from packaging waste – and convert it into high quality PLA recyclate. These can be used to make packaging for non-food applications and consumer goods. The other two Creasolv variants, presented at
K2013, were to recycle metal-plastic composites, and expanded polystyrene (EPS).
Recycling innovation Intarema is the name of the new core recycling technology from Erema. It is based on the company’s patented counter current technology, which Erema says combines flexibility and higher productivity with lower energy consumption. Inside a cutter/compactor, the rotation of the rotor disc that is equipped with tools forms a rotating spout so that material circulates the whole time. In the counter current system this spout now moves against the direction of the extruder. As a result, the relative speed of the material in the intake zone – when passing from the cutter/compactor to the extruder – increases to such an extent that the extruder screw acts in the same way as a sharp cutting edge which now cuts the plastic. This helps the extruder to process more material in
a shorter time and is more independent in terms of the pre-compacting level of the material. The inverse tangential configuration of the counter
current system ensures that the extruder screw is filled virtually pressure-free with pre-heated material. “The screw basically takes what it needs,” said Michael Heitzinger, chief technology officer at Erema. “The extruder always has the ideal filling level and is never overfilled, which makes it much better to regulate.” Results from development trials (in cooperation with
customers) with in-house waste from 30 micron LLDPE blown film show the effect of the new system on the increased process stability, productivity and flexibility of the Intarema plant. “Besides extremely easy operation, a stable and
sensitive recycling process is essential to ensure recycling rates of 100 % high-quality recyclate in virgin
18 FILM & SHEET EXTRUSION | January/February 2014
www.filmandsheet.com
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