Plastics Technology

JAN 2019

Plastics Technology - Dedicated to improving Plastics Processing.

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Traditionally, bottle-grade PET lacked the melt strength and slow crystallization necessary for use in EBM applications. Within the last six years or so, improved EPET resins hit the market. One example is DAK's Array EBM with enhanced melt strength. Another is Polyclear EBM from Indorama, described by new-business development manager Frank Ebbs as designed for clear, high-gloss EBM containers with or without handles that offer improved drop performance and can be recycled with the clear PET PCR stream with no detrimental effect. Similarly, Eastman Chemical, a major PETG producer, launched Aspira One for EBM in late 2012. It is a proprietary copolyester designed specifically for compatibility with recycling code No. 1 PET. When asked to comment on industry rumors that Eastman may exit the EBM resin business, the company's global business manager, Brad Potter, told Plastics Technology, "Eastman remains committed to the EBM container market and to meeting the industry's evolving require- ments. PETG continues to provide unmatched performance in terms of quality, design flexibility and processability and does not require brands to lower their performance standards. At the same time, we recognize the impor- tance of sustainability to our customers—and to their customers— and so we are actively exploring a range of approaches, including but not limited to mechanical recycling, that will allow them to meet both their performance and sustainability objectives." Availability of adequate EPET material to support growing demand does not appear to be an issue. Rollend says, "We think the supply of EPET is more than sufficient to meet the current demand at this point in time." Indorama's Ebbs agrees. HOW BIG IS EPET'S POTENTIAL? DAK's Rollend pegs the current EPET market size in the range of 100 million lb/yr. He sees opportunities in large handleware (greater than 60 fl oz), particularly in dishwashing and laundry detergents. Agricultural chemicals and automotive fluids also beckon. Non- handleware applications include wide-mouth jars and some narrow- neck bottles. "Non-handled, wide-mouth jars of various shapes and sizes are being commercialized with DAK's Array EBM resins. These include jars for jams and jellies; liquor flasks of 100, 200, and 375 ml; and tall wide-mouth jars." He also points to future opportunities in personal care (health and beauty aids), nutritional supplements, pharmaceuticals, and niche food and beverage products. Indorama's Ebbs anticipates that EPET will win market shares in juice, tea, nectar, water, olive oil and laundry detergents. He says the initial applications were juice and tea in containers with handles. "The newer applications are household, food and water packaging." Rollend cites a number of factors in favor of EPET over PETG for consumer packaging. One is its relatively low cost: "DAK Americas' Array EBM product was developed as an EPET formulation with significantly more melt viscosity at affordable costs." Another is greater tolerance for recycle. He says that most PETG polymers cannot meet the rigors of a 25% and 50% recycle loading, as called for in the "Critical Guidance" document from the Association of Plastic Recyclers (APR), whereas DAK's EPET is optimized for regrind use up to 50% or more. Moreover, Rollend notes that machine builders have learned how to deal with the idiosyncrasies of higher-viscosity EPET materials on existing EBM wheel and shuttle machines. Notes Bekum's Slenk, "We have been developing the technology to run EPET for years and now have over a dozen machines currently running fully automated, round-the-clock production of PET handleware bottles. This trend is continuing, as we have several new machine orders for EPET applications." Other points cited by Rollend: • Brands have begun to encourage EPET use by reducing their perfor- mance specs—notably in drop impact. If you have a secure handle, the container is less likely to drop. • EPET has melting properties similar to stretch-blow PET resins. • EPET crystallizes, so it can be reprocessed in standard PET crystal- lizing and drying equipment. • EBM tooling is typically less expensive than preform injection and blow tooling for the PET stretch-blow molding process. HOW DOES PROCESSING EPET COMPARE WITH PETG? Sources at EBM machine builders—such as Slenk at Bekum; Bill Farrant, president of Kautex Machines; and Bob Jackson, president of Jackson Machinery, which represents Hesta Blasformtechnik of Germany—are in substantial agreement on the processing similarities and differences between EPET and PETG, and the consequent implica- tions for machinery selection. Processing temperatures for EPET are much higher—over 500 F, vs. around 400 F for PETG. At the same time, it's important to keep EPET melt temperatures as low as possible to main- tain melt strength. According to Slenk, "Hang strength is a challenge with this material, and parison formation becomes difficult if it's too hot." One answer, machine suppliers agree, is to limit screw rpm and thus shear heating. That can limit throughput, so an EPET EBM machine could benefit from a larger extruder or one with longer L/D than a PETG machine. Hesta, for example, offers both 24:1 and 32:1 screws for its machines. Head design is also important to prevent overshearing the melt, Slenk points out. DAK's Rollend adds that screw design is most critical in processing EPET with high levels of regrind, in order to prevent surging and consequent tail-length variation that has a strong influence on overall container wall-thickness control. Non-handled, wide-mouth jars of various sizes and shapes are being commercialized with DAK's Array EBM resins. 18 JANUARY 2019 Plastics Technology PTonline.com E P E T B L O W M O L D I N G Close -Up On Technolog y

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