PETpla.net Insider 04 / 2019

MATERIALS / RECYCLING PET planet Insider Vol. 20 No. 04/19 www.petpla.net 39 Washing modules for the recycling of polyolefins Clean results Demand from customers, as well as the increasing number of criteria required for the recycling of re-usable materials from the waste flow, have inspired Krones to develop a washing technology for polyolefins, too. This was recently launched on the market under the name of MetaPure W-PO. The MetaPure W washing module from Krones was developed and built for continuous operation in the recycling process of PET con- tainers. During this time, there have also been demands in the market to recycle polypropylene (PP) and polyethylene (PE), in order to render them suitable for high-grade re-use. One of the key characteristics of polyolefins is that their density is lower than one, hence they float on the water’s surface. PET, on the other hand, is significantly heavier than water, and therefore sinks to the bottom (table 1). Polyolefins: < 1 PET: 1.38 to 1.40 PP: 0.90 to 0.915 LDPE: 0.915 to 0.935 HDPE: 0.94 to 0.97 Table 1: Comparison of density (in g/ cm 3 ) PET vs polyolefins The polyolefins’ relatively low density, and thus their ability to float, are very helpful in the washing process for PET when it comes to separating the cap material from the PET itself. In the washing process for polyolefins, this material charac- teristic did require some procedural adjustments. However, the overall concept continues to be based on the experience gathered in the field of PET washing technology. Individually tried-and-tested units were adapted to suit the PO-specific traits, but the process-engineering features of Krones’ washing technol- ogy remained unchanged. The high quality washing achieved during in- house trials was validated in exter- nal laboratories, and confirmed by the production of test specimens. Odour-neutrality One problem encountered with polyolefins is material collection, and the resultant side-effects. Gener- ally speaking polyolefin packaging is that which is collected in household rubbish, or in separate bins or sacks for plastics. Since this material is usually not cleaned before recycling, it is invariably in contact with organic residues. This creates an enormous biological and chemical loading, which leads to an unpleasant smell. It is then relatively difficult to make sure the end-product is odour-neutral. However, with the standard wash- ing module used in the in-house pilot plant, optimum results in regards to cleanliness and odour-neutrality could indeed be achieved, says Krones. In the future, the washing mod- ules for PET and polyolefins will be available under the names of Meta- Pure W-PET and MetaPure W-PO respectively. www.krones.com Recycling Special Visit us: www.bericap.com Total development of neck and closure • New 26/22 1-start PET neck: weight savings for closure and neck of 50% compared to their predecessors Consumer convenience • Good grip: closures easy to handle for consumers • Slit and folded TE band: safe application, easy first opening Suitable for aseptic, carbonated an non-carbonated drinks REDUCE IT We call it optimized material usage Optimized neck and closures: • 1810 • 1881 • 26/22