A project funded by the the Fraunhofer Institute for Process Engineering and Packaging has developed a grease barrier based on starch, as an alternative to the perfluorinated compounds currently used to impregnate paper and cardboard packaging materials for the retail of grease and oil containing products.
In collaboration with the Fraunhofer Institute for Applied Polymer Research, Fraunhofer IVV evaluated the suitability of hydroxypropylated starches to act as grease barriers. These HP starches are said to possess very good film formation properties, making them ideal for use as coatings. The studies showed that in principle grease barriers can be achieved using HP starches from tubers, cereals and leguminous plants.
The starch derivatives that were developed are said to provide a very effective grease barrier when applied in amounts of 20g/m2 upwards. This barrier remained fully intact when the packaging was subjected to extreme climatic conditions (60degC and 60 per cent relative relative humidity) for a period of five days. The best results were obtained using a starch with a high amylose content.
A coating plant with a slot die was used for the trial, which demonstrated that corrugated and folded samples possessed as good quality a barrier as commercially available impregnated products.
The new, alternative polymer coating is biodegradable and compatible with paper recycling technology. From a cost point of view, it is said to be as favorable as a PE coating.
Fraunhofer IVV has patented the use of starch as a grease barrier, which is now developing board packaging systems for dry petfoods that contain high levels of surface grease. Industrial partners wishing to participate in this work are invited to contact the institute.
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