Extremely pure polycarbonate having good natural colour and thermal resistance and a device and method for production of same

摘要

Aromatic polycarbonate, comprising less than 5 ppm of aromatic chloro compounds, less than 0.5 ppm of dichloromethane, less than 5 ppm of univalent phenol and less than 0.5 ppm of aromatic compound, which is free of chlorine, is new. Independent claims are included for: (1) a device, for degassing of solvent-based polycarbonate melt, comprising a degassing extruder with at least three degassing zones, and a zone, before the degassing zones, for dispersing a stripping agent; and (2) the preparation of the polycarbonate.