It is common practice throughout Europe when extruding APET sheet
to apply a 5% PE laminate prior to thermoforming a food container to
effect an efficient lid seal for Modified Atmosphere Packaging
applications with meat and chicken in particular.
This results in some 40% APET / PE regrind being generated from edge
trim and skeletal waste that conventional crystallisers can not
process as the PE melts below the APET crystallising temperature
causing discolouration and sticking so converters are left with huge
stocks of valuable material that can not be processed.
Based on the success achieved to date by UPM with their infrared dryer
(IRD) a major multi national PET sheet and food tray packaging
producer supplied 1000 kilos of their APET / PE regrind to enable
trials to be carried out in the UPM demonstration facility to
determine if infrared technology could offer a solution based on lower
operating temperatures and residence times in comparison to a normal
crystalliser for APET which by virtue of the design parameters relies
on at least one hour at 140°c and continuous agitation.
The UPM infrared dryer (IRD) trials on APET / PE showed excellent
results with crystallinity at 33% after only 4 minutes at 115°c
without any discolouration or sticking allowing the material to be
used in PET sheet extrusion as the core layer with a co-extruder
applying a 25 micron coating top and bottom forming a sheet
construction of ABA which is ideal for thermoformed products used in
food contact applications.
UPM report that the majority of their 50 IRD systems operating 24 / 7
world wide are crystallising and drying APET regrind to a final
moisture content of 50ppm so APET / PE opens a new market sector for
IRD offering converters an opportunity to re-use their scrap mountains
into a saleable product.
UPM
Solve APET / PE Scrap Mountain