VORRICHTUNG UND VERFAHREN ZUM FORMEN VON POLYESTERGEGENSTÄNDEN MIT NIEDRIGEM ACETALDEHYDEGEHALT DIREKT AUS DER SCHMELZE DURCH VERFLÜCHTIGUNG MITTELS EINER ENTSPANNUNGSVORRICHTUNG

摘要

An apparatus and a method for molding of polyester articles having low acetaldehyde content directly from a melt without intermediate solidification of the molten polyester. A melt to mold process is used wherein an acetaldehyde stripping agent is mixed into a polyester melt before devolatilization in a flash tank. The devolatilized polyester is pumped out of the flash tank and injected into a mold, thus forming a shaped article. The apparatus may include one or more flash tanks in one devolatilization line, or multiple devolatilization lines may be used stemming from one main polymerization reactor. The final shaped article should contain less than 10 ppm of acetaldehyde.