Described as a durable, cleaner and lighter alternative to high-impact polystyrene (HIPS), a PETG foam made with Eastalite copolyester from Eastman Chemical Co. (Kingsport, TN) has been introduced by Pacur LLC (Oshkosh, WI) for medical packaging applications. Eastman developed the formulation, with Pacur contributing its sheet extrusion expertise. The collaboration, which also includes thermoformer Tek Pak (Batavia, IL), was a focal point at the Eastman booth (2180) at MD&M East and PLASTEC East in New York this week.
The skin of the Pacur PETG foam is made from Eastar copolyester 6763, while the core is made with Eastalite copolyester. The skin layers allow the same heat seal and product contact surfaces that have a long history of use in the medical industry, but the foamed core gives the packaging a lighter weight and provides a cushioning effect. The unique structure lends the opaque material impact resistance. When thermoformed into packages, the multilayer sheeting offers a physical barrier to microbes and product protection over the desired shelf life for medical devices.
The material is 40% lighter than alternative clear materials and 20% lighter than polystyrene, says James Banko, Vice President, Sales, at Pacur. It also has significant processing benefits, he adds. "It cuts much better than polystyrene, and is cleaner in terms of angel hairs and particulates. This is very important in medical packaging, of course, where cleanliness is of paramount concern," says Banko. "And you won't see any fracturing when it's removed from the mold. The lightweighting and ease of processing of the material lead to an overall system cost saving," adds Banko.
Tony Beyer, President of Tek Pak, was impressed by the material's performance as he ran tests on prototypes. "We analyzed all of the difficulties a processor might run into, and I was honestly surprised by how fast it ran—faster than an equivalent polystyrene material. It stripped off the mold properly, did not tear and the foam required less heat, so there was less heat to take out. Getting out the heat is a problem—you know, that's where the money is," Beyer told PlasticsToday.
Containers formed from Eastalite copolyester extruded sheet can be designed with deep undercuts and durable living hinges, and exhibit less stress whitening than packaging molded from HIPS, according to Eastman. Eastalite also can provide greater tear strength while retaining color stability and functional integrity following sterilization by ethylene oxide or gamma irradiation.
"When you're dealing with a risk-averse industry such as medical, getting unbiased feedback from companies such as Pacur and Tek Pak is huge for us," Eastman's Aneta Clark, who is responsible for market development in the medical arena, told PlasticsToday.
Eastalite copolyester is made without materials of concern, including butadiene, bisphenol A, bisphenol S, ortho-phthalates or halogens such as chlorine or bromine. The material is compliant with select ISO 10993 requirements for medical device biocompatibility and applicable parts of ISO 11607.