A leading engineering polymer manufacturer has introduced an alloy of PPE (Poly Phenylene Ether) with Polypropylene called Noryl PPX 615 for retort packaging. Retort packaging or more precisely; Retort sterilization uses superheated steam to cook food while killing pathogens. Noryl PPX 615 resin is targeted at large trays used to handle retort pouches during sterilization and conveyance. This alloy has a special balance of broad chemical resistance, excellent thermal and hydrolytic stability and stiffness with ductility.

This food-preservation method is most commonly used for MREs - a military acronym that means Meals Ready to Eat. MREs are highly portable, compact and easy to prepare - no dishes or water are needed for preparation. While the entree may be eaten cold when necessary, it can also be heated in a variety of ways, including submersion in hot water while still sealed in its individual entree package. Each portioned meal is enclosed in retort packaging, which consists of a heavy-duty multilayer pouch of aluminum and plastic laminate designed to maintain food quality under harsh storage and shipping conditions. Originally developed for military food use, MREs are now used by police, search and rescue teams and outdoor enthusiasts, as well as for disaster preparedness kits. Retort packaging is also used for consumer products such as pet foods and in non-food institutional sectors such as healthcare. The multi-billion dollar retort pouch industry is growing.

The technical challenges of retort sterilization, however, can be sizeable. The process involves forcing steam at high pressure and temperatures up to 125 degree C into a chamber containing rigid sterilization trays, stacked up to 13 high, in which the pouches sit for as long as 90 minutes. This requires that the tray materials have excellent heat-distortion performance under load, as well as dimensional and hydrolytic stability, stiffness and impact strength. Resistance to common foods and cleaning chemicals are also requisite properties, as the trays must be cleaned after each use and may be exposed to cooking oils and other substances. Common tray materials are metals, wood or plastics. However, metal trays are typically heavy and can oxidize; wood can be hard to clean and has a limited number of cycles; and many plastics lack the sufficient mechanical properties needed to resist creep or warpage under the rigorous heat and humidity of retort conditions.

Noryl PPX 615- The new alloy from GE would certainly improve the market share of the plastic trays for retort packaging.