Recycling of post-consumer PET for direct food contact

3 Recycling of post-consumer PET for direct food contact 

A challenge test case study and evaluation scheme 

1-THchloroethane CHy-CCl., Halogenated hydrocarbon Volatile, polar, aggressive to PET 

Melhyl stearate CH3(CH2)16COOCH, Ester Non-volatile, polar 

The table shows that the process can eliminate volatile compounds much more efficiently than non-volatile substances. Volatiles, like toluene and chlorobenzene, are already efficiently removed by step (ii) alone. Toluene was no longer measurable at a detection limit of 0.4 ppm. The other volatile, chlorobenzene, was recovered at 5.5 % of the initial concentration after the extrusion step. After the post-condensation step, the amount of toluene in the final product was likely to be far below the limit of detection since the detection limit was already determined after the extrusion step. Chlorobenzene also could not be found above the limit of detection. These results show very impressively that a conventional recycling process (consisting of steps (i) and (ii)) for post-consumer PET removes volatile real-life contaminants very efficiently, for example solvents and fuel. An additional vacuum treatment during solid-phase post-condensation further decreases any level of volatile compounds in the final product. 

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The German BfR (former BgVV) published recommendations on the mechanical recycling of post-consumer PET for direct food contact... 

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