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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.
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