PET, and plastic in general, are not very effective in keeping oxygen from permeating a container and reducing the shelf life of such products as juices, teas and flavoured water. Oxygen has a degrading effect on flavour, colour and vitamin content for many beverages, making the switch from glass or metal difficult. The dilemma whether to convert to plastic containers from glass or metal, seems to be nearing a solution with the development of a clear monolayer polyethylene terephthalate (PET) with an oxygen-scavenging barrier.
This decade has witnessed the emergence of PET as one of the fastest growing sectors of the beverage bottling market. PET has the practical benefit of being lightweight, shatterproof and recloseable. It is also completely recyclable, giving it an edge under the EU's new regulations on reducing packaging waste. Though PET has clearly overtaken glass and cans as the container of choice, its use has been mainly limited to fizzy drinks and water.
A material has been developed, which when blended with monolayer PET, binds oxygen, thus preventing the degradation of products such as juices, teas and flavoured water. The product, called DiamondClear, is currently being tested before being submitted for regulatory approval. DiamondClear is blended at the preform injection stage, making the technology work equally well with one-step and two-step injection stretch blow molding operations, eliminating the need for high cost co-injection equipment necessary for multi-layer barrier systems. Unlike systems to apply internal or external barrier coatings, DiamondClear preforms can be produced centrally, then shipped to any blowing location.
10-Oct-05 
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