Aluminium foil – the traditional packaging material used for potato crisps, other salty snacks and coffee – is notoriously difficult to recycle.
But in a major breakthrough, a researcher has discovered a new, recyclable coating to replace the type of “metallised” packaging that blocks out oxygen.
The discovery was made by Jiaying Li a PhD student at the University of Twente, working with the Dutch Advanced Research Center Chemical Building Blocks Consortium (ARC CBBC), Wageningen University, BASF and packaging coating maker AkzoNobel.
Current crisp packaging comprises several layers and requires a lot of energy to produce.
“The use of polyelectrolytes in the coatings industry is not new,” explains Andre van Linden, AkzoNobel’s director of coatings technology. “But these coatings are normally built up step by step, so industrialisation of this method would be too complex, time-consuming, expensive and impractical.”
But Li has devised a process that involves the smart combination of two water-soluble polymers (polyelectrolytes), resulting in all the functionality of the traditional packaging being delivered by one recyclable layer.
“The new one-step approach that’s being developed through the ARC CBBC means the use of polyelectrolytes is much closer to becoming industrialised,” said van Linden.
“Our initial results show that the coating has great potential for future use in packaging to protect food from oxidation,” explained Li. “We’re also focusing on improving other properties, such as water resistance and strength.”
AkzoNobel believes the new discovery will set the way for a truly environmentally friendly packaging solution for the food industry. No organic solvents are required to make the packaging, which would be easy to recycle.
Now the researchers will look to use bio-derived polyelectrolytes, which are 100-per-cent natural, extracted from the likes of shrimp shells or waste from the wood processing industry.
“With the versatility of natural polyelectrolytes, we’re entering the era of becoming less dependent on synthesised polymers,” said Li.
“In the end, the polyelectrolyte coating we’re developing might be less shiny, but it will serve the same purpose and make recycling much easier.”
Main image: @INimages via Twenty20.