PETplanet Insider Vol. 26 No. 10/25 www.petpla.net 13 Editour first go through a sieving process in which large flakes and fine particles are sorted out. This is followed by metal detection for ferrous and non-ferrous metals. It follows in the third quarter. The second step is the removal of coloured and opaque flakes. In the final step, Unisensor uses laser spectroscopy to remove PVC, PC and other non-PET elements. The PET flakes are then thermally melted and pumped through a special vacuum process with continuous deep condensation. This significantly increases the intrinsic viscosity (IV) - around 0.01 dl/g per minute - which enables continuous process control. During this melting process, impurities (including NIAS, bisphenol A, and spin oils) are efficiently removed - at a level that complies with the strict EFSA and FDA approvals. This is followed by pellet crystallisation and final cleaning (acetaldehyde removal). The material is then stored and, if necessary, mixed with new material in a mixing plant. (Fig. 3) www.sgt-pet.com Fig.2: View into the material cooler of the new LSP system for rPET Fig. 3: The mixing system for vPET and rPET is at least as complex as the LSP system
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