Non-stick coating reduces food waste, facilitates recycling

Materials World magazine
1 Dec 2007
Plastic bottles

Banging the plastic bottle in frustration to release the last of the ketchup or mayonnaise may soon be a thing of the past.

Researchers at the Fraunhofer Institutes in Germany are using plasma processing technology and novel thin films, 20nm thick, to explore the potential for non-stick packs.

‘We are developing packaging materials that reduce leftover traces to half or less,’ says Dr Cornelia Stramm, Head of Functional Films at the Fraunhofer Institute for Process Engineering and Packaging IVV in Freising.

She is tight lipped about the exact composition of the films, but explains that a variety of hydrophobic and hydrophilic functional coatings are being analysed, and will be optimised for improved adhesion, mechanical resistance, and performance under varying temperatures and in contact with acids or alkalis.

‘The coatings must not change the properties of the packaging materials,’ adds Dr Michaela Muller of the Fraunhofer Institute for Interfacial Engineering and Biotechnology in Stuttgart. ‘They must remain capable of being industrially processed to form bottles, tubes or stand-up pouches.’ So far, the technique has only been applied to polymeric substrates.

If successful, the technology could reduce food waste and make recycling easier. Removing leftovers from packaging is expensive, time consuming and water intensive. If the products in question are pharmaceuticals, chemicals or pesticides, waste has to be more carefully disposed of. In some cases, up to 20% of the substance is left in the container.

‘This is a great example of packaging innovation based on biomimetics,’ says Dr Paul Butler of Packaging Materials and Technologies Ltd in Henley-on-Thames, UK. ‘Nature contains many examples of self-cleaning superhydrophobic surfaces, such as the lotus leaf. Numerous packaging applications exist for this technology, such as for closures and other components used in the dispensing of viscous liquids.’

He adds, ‘Many of these products have recently migrated from glass and plastic bottles with conventional closures to upside down squeezy containers with one-way valves, which makes it easier to remove the last serving.’

Last year, Unilever launched the ‘Easy Out!’ non-stick package for Hellmann’s mayonnaise. The polypropylene/ethyl vinyl alcohol pack has a specially formulated inner bottle surface that is claimed to have slip properties.