EMS Inventa Fischer handed over the Turn-key PBT plant in mid February 2004 to DuBay Polymer GmbH, a joint-venture between DuPont and Bayer, located at Hamm-Uentrop (Germany), for full commercial production of their new facility following a successful start-up in mid December 2003.
The 80,000 t/a (240 t/d) Polybutylene-terephthalate (PBT) unit was Turn-key contracted in 2002 to Inventa-Fischer, Berlin, the engineering and technology member of the EMS-Group, Switzerland. The total investment budget was approx. 50 million Euro.
The DuBay joint-venture selected Inventa-Fischer’s 2R (Two Reactor) technology which was recently developed for the fabrication of all polyesters (PET, PBT, PTT, PEN) and its co-polymers. Its design covers the use of all appropriate raw materials such as DMT, PTA and others. This techno-logy is characterized by the tower reactor ESPREE where ESter-reaction and PREpolycondensation are activated simultaneously, together with the Discage finishing reactor, to obtain all the required PBT-grades in melt phase which range from melt flow indexes (MFI) of 72 to MFI 8. The MFI 8 corresponds to a zero-shear-viscosity of nearly 1200 Pa·s.
New surface-active process and construction elements within the ESPREE-Tower, using no mechanical stirring devices, ensure the most efficient short-term reaction and enable a soothing temperature and pressure profile which, all together, render an extremely low heat stress to the product. Also, the Discage could again demonstrate its high reaction effectiveness and reliability to obtain a constant and stable production quality at low and high viscosity grades. As a result, just a few hours after the initial start-up, a high grade PBT with excellent color, filterability and all the other polymer characteristics within the tight quality specification was obtained.
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