Process for producing polyester articles having low acetaldehyde content

Disclosed is a process for removing acetaldehyde from polyester which comprises the steps of a) transporting molten polyester to a vented, continuous screw conveyor having a polymer compression zone, b) rotating the screw of said conveyor so as to compress and convey through the extruder the molten...

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Bibliographische Detailangaben
Hauptverfasser:	OLSEN, ERIC G, NELSON, GREGORY W, CHERRY, CLINTON
Format:	Patent
Sprache:	eng
Schlagworte:	AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING CHEMISTRY COMPOSITIONS BASED THEREON INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS METALLURGY ORGANIC MACROMOLECULAR COMPOUNDS PERFORMING OPERATIONS SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR SHAPING OR JOINING OF PLASTICS THEIR PREPARATION OR CHEMICAL WORKING-UP TRANSPORTING WORKING OF PLASTICS WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL
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Beschreibung
Zusammenfassung:	Disclosed is a process for removing acetaldehyde from polyester which comprises the steps of a) transporting molten polyester to a vented, continuous screw conveyor having a polymer compression zone, b) rotating the screw of said conveyor so as to compress and convey through the extruder the molten polymer for a time of less than 15 minutes and at a temperature of less than 300 DEG C., c) simultaneously with step b), flowing a purge agent into and out of said extruder to thereby remove volatile impurities and avoid appreciable build-up of acetaldehyde, and d) conveying the devolatized polymer melt to a mold wherein an article of manufacture is formed.