Uhde Inventa-Fisher GmbH, Berlin/Germany has developed a new recycling process for polyethylene terephthalate (PET), which is increasingly being used for beverage packaging. This flake-to-resin process (FTR) allow PET pellets or preforms to be produced in only one process step from the PET prepolymers by melt condensation. Terephtahlic acid and monoethylene glycol are converted into PET prepolymers in a special reactor, and the conventionally washed PET flakes are melted in a multi-screw extruder. The molten post-consumer PET flakes are partially depolymerized by adding ethylene glycol, to achieve the level of the virgin material prepolymer. The two melts are then blended and polymerized in a reactor, and after filtration, this melt can be processed either into pellets or directly into preforms. This FTR process offers possibilities to produce regulation-compliant food-contact packaging from post-consumer PET flakes.
