GE claims that it developed the resin in response to increased market demand for cost effective yet safe and attractive packaging. The PPO/polystyrene alloy resin offers increased stiffness at higher temperatures compared to polypropylene (PP), thus reducing the risk of food spills when used in microwaveable food trays.
The new Noryl PKN material also offers better impact performance at freezer temperatures compared to common PP based materials.
Linpac Plastics, a pan-European manufacturer based in the United Kingdom, recently selected Noryl PKN resin for its new LINcool single-use trays, designed for microwave cooking. The trays needed to be rigid enough to handle ready-meal dishes without flexing and allow the consumer to directly take the meal from the freezer to the microwave.
The heat resistance of the resin means that while the outside of the package remains cool, thereby reducing burn potential, it still keeps the food inside hot.
"Based on its exceptional property performance balance, Noryl PKN resin can be a great fit for many freezer-to-microwave packaging applications," said Rob de Jong, industry manager for GE Advanced Materials' plastics performance packaging segment in Europe.
The Noryl PKN resin portfolio presently includes six commercial grades, both transparent and opaque, covering a wide heat resistance range. Noryl PKN resins can be applied in monolayer, multi-layer and foamed applications. Besides the single-use/microwave category, Noryl PKN resin is also durable enough for use in cookware/houseware and tableware applications.
GE has also recently developed PPX 615 resin, an alloy of polyphenylene ether (PPE) and polypropylene (PP), which brings together two incompatible resins via a patent-pending alloying technology. The result, claims GE, is low-temperature toughness, creep resistance, melt strength and thermal stability.
The material is targeted at the large trays used to handle retort pouches during sterilisation and conveyance due to its special balance of broad chemical resistance, excellent thermal and hydrolytic stability, and stiffness with ductility. GE also claims that the new material offers good surface appearance, a wide processing window, and fast cycle times, all of which can help moulders improve their bottom line.
Retort sterilisation uses superheated steam to cook food while killing pathogens. Today, this food-preservation method is most commonly used for ready meals.
The technical challenges of retort sterilisation can be sizeable. The process involves forcing steam at high pressure and temperatures up to 125C 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 tray materials have excellent heat-distortion performance under load, as well as dimensional and hydrolytic stability, stiffness, and impact strength.
Noryl PPX 615 resin is GE Advanced Materials' answer to these challenges and represents the newest addition to the company's growing family of thermoplastic alloys. These products are available from the company in filled and unfilled resin grades and can replace materials such as olefins, ABS, nylon, wood, and metals in a variety of applications.