Page 83 - Plastics News August 2024
P. 83
PRODUCT NEWS
line, including NIR and color automatic sorters, notably the percentage of lost fines. The table
then through the wash line and the flake sort- below shows the main results from this analysis.
ing equipment. Similar parameters were used for
all three types of bales, with only minor adjust- The study shows that the overall clear washed
ments done to optimize the process for each flake yield can be considered similar for the
sample. While the initial target was to run the three types of sourced material. The 56.5% yield
material at the line-rated capacity, the line speed for the control material is considered to repre-
when running the 90% material was lowered to sent a low-quality bale for the reclaimer, as a
60% of normal throughput, due to contamina- high-quality bale provides a yield of around 70%.
tion in the sink/float bath and clogging in the ex- Furthermore, as expected, the lost fines content
traction screw coming out of the prewash. The is increasing as the percentage of thermoforms
reclaimer commented that this problem could increases. However, for most reclaimers supply-
be solved if there was a need to process mate- ing to the sheet industry, the lost fines fraction of
rial with very high levels of thermoformed PET 8.1% obtained for the 90% sample could proba-
on a regular basis. bly be considered as acceptable. For those sup-
plying exclusively the bottle industry, the control
Flake outputs from these trials were then sent sample using 41% PET thermoform may be a
to an independent lab to analyze, among others, more acceptable result.
their color, haze, and intrinsic viscosity (IV). As it
is a main concern with thermoform recycling, the “Considering what we often hear about the very
sorting and washing yields were also measured, high level of lost fines when converting PET ther-
moforms, it was surprising to find the relatively turer of PET sheets and thermoform containers.
low level of lost fines, even for a modified pro- Sheets containing a mix of 25% of the sample
cess,” confirmed Michel Gosselin, the project and 75% of post-consumer recycled (PCR) bot-
manager. “While increasing, the fact that the tle flakes were processed using extruders com-
numbers remained relatively reasonable even monly used in the industry. Once produced, the
for a bale that is made almost entirely of ther- sheets were evaluated for color, haze and IV, as
moforms is promising.” seen in the table below. As a control sample, a
sheet made of 100% post-consumer recycled
Finally, to move one step further up the recycling (PCR) bottle flakes was also processed and ana-
chain, 5,000 pounds of clean flakes from the lyzed.
90% sample were sent to a Canadian manufac-
August 2024 PLASTICS NEWS 85
