1 444 k €
The quality of recycled plastics is essential from a societal point of view and, consequently, for the packaging recycling industry. Recycled materials will be better suited to higher-added-value markets, like the food industry, if they retain similar characteristics to those of the original material.
Achieving this level of quality is not just an economic and environmental issue, it is also a health and safety issue when it concerns food-grade packaging. The creation of a “closed loop” model, with materials reused in their original application many times, requires draconian legislative standards. It must be possible to prove that the recycled materials have equivalent functional characteristics to those of virgin materials.
Thanks to the combined efforts of the plastics industry and the European Food Safety Authority (EFSA), the first ‘closed-loop’ recycling model has been developed for polyethylene terephthalate (PET) water bottles. PET’s intrinsically good ‘barrier’ properties limit its potential for different types of contamination by exogenous compounds. Decontamination processes based on the principle of high-temperature vacuum thermal desorption can ‘deep clean’ PET and meet health and safety standards. These technologies have demonstrated their effectiveness over many years.
These “deep cleaning” technologies cannot be effectively used for materials with poorer barrier properties, such as polyethylene (PE) and polypropylene (PP), as the materials collected are likely to have a wider range of contamination.
The SUPErPE project aims to conduct a large-scale trial of a process based on the extraction of supercritical carbon dioxide (CO2), which is a technology commonly used in other fields (extraction of caffeine from coffee or the taste of cork, etc.). At certain specific temperature and pressure conditions, CO2 acts as a “super solvent” capable of solubilising a wide range of contaminants in the targeted material.
The aim of the SUPErPE project is to approve a purification method for recycled PE and PP using supercritical CO2 to restore the food-grade properties of resins. This work is fully in line with EFSA’s risk assessment requirements for recycled resins. Particular attention is being paid in this project to the economic viability of the process by optimising the technology.
This project is an extension of a previous interministerial fund project, REPALI II, which provided proof of concept for this technology for decontaminating polyolefin resins.