Analytical Quality Assurance for PET-Recycling

Due to modern environmental packaging requirements the question of recyclability of post-consumer PET into new food packaging applications is of increasing interest. In consequence, the recycling process and the quality assurance of the PET recyclate must satisfy special requirements. The Fraunhofer-Institute has modified the so-called "Challenge-Test" evaluating the cleaning efficiency of PET recycling processes in a more economic and user-friendly way. A Challenge-Test investigates if a recycler provides a PET recyclate quality suitable for direct food contact applications. In worst-case scenarios, misuse of PET beverage bottles such as storage of domestic chemicals and the possible introduction into the recycling stream is simulated by means of the artificial contamination with model contaminants of post-consumer PET material. In addition, a special analytical quality assurance based on a high temperature gas chromatographic headspace analysis was developed to control the input and output PET stream of industrial PET recycling plants. With help of these two components - the cleaning efficiency evaluated by a Challenge-Test and a gas chromatographic headspace screening - a high protection level for the consumer is given in the sensitive area of recyclate application in food packaging.