ULTRA-HIGH PURITY POLYCARBONATES HAVING GOOD INHERENT COLOR AND THERMAL RESISTANCE AND A DEVICE AND A METHOD FOR PRODUCING THE SAME

The invention relates to polycarbonates with extremely low residual levels of volatile constituents and thermal degradation products, and also improved optical properties, especially Yellowness Index (YI) and good thermal stability, from solvent-containing polymer melts. The invention further relate...

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Bibliographische Detailangaben
Hauptverfasser: KIRCHHOFF JOERG, KOHLGRUEBER KLEMENS, VANDER EYNDE JOHAN, RECHNER JOHANN, RUYTINX BERT, KOENIG THOMAS, BIERDEL MICHAEL, VAESJOHAN, BRUYNSEELS FRANK
Format: Patent
Sprache:eng
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Zusammenfassung:The invention relates to polycarbonates with extremely low residual levels of volatile constituents and thermal degradation products, and also improved optical properties, especially Yellowness Index (YI) and good thermal stability, from solvent-containing polymer melts. The invention further relates to an apparatus and a process for preparing these polycarbonates with the aid of a devolatilizing extruder with at least three devolatilizing zones, and zones for introducing entraining agent into dispersion are present upstream of at least three devolatilizing zones.