RECYCLED POLYPROPYLENE FOR FOOD-PACKAGING - PRELIMINARY EVALUATION OFTHE INFLUENCE OF PREPROCESSING TREATMENTS AND PROCESSING

A preliminary study was conducted on the properties of recycled polypr opylene and the possibility of its use for food packaging. Different p re-processing and processing conditions were tested on containers put in contact with food to simulate normal use. Typical operations of pol ymer recycling, compression moulding and film blowing, were carried ou t to produce the materials for testing. Permeability, mechanical and m igrational properties were checked as they are the most important para meters for evaluating the final material in relation to its possible u se. The washing step was found to be very important and the use of sol vent always gave the poorest results. The final process (extrusion or moulding) is the cause of material degradation, while drying and addit ion of stabiliser had positive effects. Migration results were often a bove regulatory limits.