Plastics Technology

JAN 2019

Plastics Technology - Dedicated to improving Plastics Processing.

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Orange, a Coca-Cola Co. brand, which converted from PETG for recy- clability. The first big EPET conversion was the 89-oz Tropicana orange- juice jug from Pepsi, which converted, not from PETG, but from white opaque HDPE several years ago in order to take advantage of the crystal clarity of PET. Industry sources also point to EPET conversions from PVC in non-beverage products for improved recyclability. The resulting market shift has been assisted by the two main domestic suppliers of EPET resin, DAK Americas and Indorama Ventures. They have devel- oped high-melt-viscosity EPET grades for EBM with hang strength, toughness, and reduced crystallization rates. The inherent challenge of parison formation with PET's poor melt strength (or "hang strength" in EBM) origi- nally resulted in the development of EBM-grade copolyester resins, such as PETG, first introduced over 30 years ago. "Unfortunately, copolyester materials are not readily managed in the established PET recycle infrastructure due to their lower drying and melting temperatures," says Bekum's Slenk. George Rollend, technical fellow at DAK Americas in technical marketing development, notes that over the years, container recyclers have had major processing issues with a relatively small percentage content of PETG present in the bottle recycling stream. "This is due to the substantially lower melt point of PETG vs PET," he explains. "During recycle processing, the lower-melting amorphous PETG begins to stick to the conventional bottle-grade PET within the recycle stream, causing agglomeration and clumping of the total stream. This causes interruptions in the process, and makes it impossible to achieve a quality recycle product. As a result, PETG is considered a contaminant by recyclers, and there is a movement to eliminate PETG from carrying the No. 1 recycle code on containers." A shifting market preference for extrudable PET (EPET) versus PETG copolyester in order to make extrusion blow molded (EBM) clear bottles that can be recycled with the stan- dard PET stream appears to be gaining momentum. The recycling issue was given a major push by the State of California in October 2017, with the passing of Assembly Bill 906, which revised the state's definition of PET to exclude PETG—essentially barring products made from the glycol-modified copolyester from using ASTM resin identifica- tion code (RIC) No.1 ("PETE 1"), in order to prevent contamination of the post-consumer recycle (PCR) PET stream. The bill, which could have broad impact beyond California's borders, officially went into effect Oct. 1, 2018, with PETG products now falling under RIC No.7, defined as "Other," which includes materials made with more than one resin from categories 1-6. Another contributing factor is the growing popularity of clear handleware containers, especially for orange and other juices, as well as ready-to-drink (RTD) teas. EBM can mold integral through-handles, unlike stretch-blow molding of conventional PET. "Extrusion blow molding of clear bottles integrating a true through- handle and that can carry the 'PETE #1' resin symbol for recycling with PET has long been a packaging goal for consumer-products groups," says Joe Slenk, applications engineer at EBM machine builder Bekum America. One recent success story for EPET has been orange juice, such as Simply By Lilli Manolis Sherman & Matt Naitove Senior Editor & Executive Editor QUESTIONS ABOUT BLOW MOLDING PET? Visit the Blow Molding and PET Zones. Why Blow Molders Are Switching to EPET High clarity, easy incorporation of handles, and recycling resin code No. 1 are the principal drivers for converting to EPET resins for extrusion blow molding. High-viscosity EPET grades have been devel- oped with hang strength, tough- ness, and crys- tallization rates suitable for EBM. Key early successes for EPET bottles are in orange juice, such as Simply Orange, converted from PETG for superior recyclability; and Tropicana, converted from HDPE for superior clarity. Large handle- ware containers, particularly for dishwashing and laundry detergent, are targeted market segments, according to DAK Americas. 16 JANUARY 2019 Plastics Technology E P E T B L O W M O L D I N G Close -Up On Technolog y

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