Page 25 - Plastics News August 2019

FEATURES
and/or bottle scrap with their crystalline virgin
pellets and dry the blend without sticking problems. interruptions.
The key is that there must be a small percentage of
amorphous scrap and it must be thoroughly blended
ZLWK FU\VWDOOLQH PDWHULDO :KHQ WKH DPRUSKRXV FKLSV
are heated they will indeed soften and stick to any
adjacent chips or pellets; however, with the vast
majority of the adjacent particles being crystalline
virgin pellets, any clumps or agglomeration will be
small, possibly totaling two or three particles but
seldom more. These small agglomerations will pass
IUHHO\ WKURXJK WKH GU\LQJ KRSSHU ZLWKRXW FDXVLQJ ÁRZ
‡ 6KHHW H[WUXVLRQ DQG WKHUPRIRUPLQJ RI $3(7
containers: The method described above for PET
bottles will also work in the production of APET sheet
and containers. However, scrap rates encountered in
APET container production far exceed those typical in
bottle making. The sheet edge trim may total 3% of
throughput, while the web skeleton could exceed 50%,
depending upon the shape of the containers being
produced (square containers can be nested closer
WRJHWKHU WKDQ URXQG RU RYDO FRQWDLQHUV :KHQ \RX
add the occasional entire roll of sheet that did not
pass muster with quality control, the overall scrap
generated in this process can easily exceed 50% of
total throughput.
:KHQ SURFHVVLQJ $3(7 VFUDS WKDW H[FHHGV RI
the total throughput of the line, the only plausible
method of handling the high volume of amorphous
VFUDS LV WR ÀUVW UH FU\VWDOOL]H LW ZKLFK ZLOO DOORZ LW
to be dried at the elevated drying temperatures (300
F to 350 F) required for good drying without it fusing
and sticking together in the drying hopper.
25 August 2019 Plastics News