A PLANT AND AN EFFICIENT PROCESS FOR PRODUCING POLYLACTIC ACID USING LACTIDE OBTAINED FROM POLYLACTIC ACID DEVOLATILIZATION

A process of producing polylactic acid comprising the steps of: a) providing a crude lactide composition comprising meso-lactide and at least one of L-lactide and D-lactide, b) separating from the crude lactide composition a meso-lactide enriched composition and a meso-lactide depleted composition,...

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Bibliographische Detailangaben
1. Verfasser:	STEPANSKI, Manfred
Format:	Patent
Sprache:	eng ; fre
Schlagworte:	CHEMISTRY COMPOSITIONS BASED THEREON MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS METALLURGY ORGANIC MACROMOLECULAR COMPOUNDS THEIR PREPARATION OR CHEMICAL WORKING-UP
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Beschreibung
Zusammenfassung:	A process of producing polylactic acid comprising the steps of: a) providing a crude lactide composition comprising meso-lactide and at least one of L-lactide and D-lactide, b) separating from the crude lactide composition a meso-lactide enriched composition and a meso-lactide depleted composition, wherein the meso-lactide enriched composition contains at least 80 mol-% of meso-lactide based on the total content of lactide, c) polymerizing a polymerization composition comprising meso-lactide and at least one of L-lactide and D-lactide to a crude polylactic acid composition and devolatilizing the crude polylactic acid composition so as to produce a purified polylactic acid composition and a composition containing unreacted lactide, d) subjecting the meso-lactide enriched composition and at least a portion of the composition containing unreacted lactide to a purification comprising at least one crystallization step so as to produce a purified meso-lactide enriched composition, e) subjecting the meso-lactide depleted composition or a mixture of the meso-lactide depleted composition and a portion of the composition containing unreacted lactide to a purification comprising at least one crystallization step so as to produce a purified meso-lactide depleted composition, wherein the polymerization composition contains at least a portion of the purified meso-lactide enriched composition produced in step d). Procédé de production d'acide polylactique comprenant les étapes suivantes : a) mise à disposition d'une composition de lactide brut comprenant du méso-lactide et au moins un des L-lactide et D-lactide ; b) séparation à partir de la composition de lactide brut d'une composition enrichie en méso-lactide et d'une composition appauvrie en méso-lactide, la composition enrichie en méso-lactide contenant au moins 80 % en moles de méso-lactide par rapport à la teneur totale en lactide ; c) polymérisation d'une composition de polymérisation comprenant du méso-lactide et au moins un des L-lactide et D-lactide en une composition brute d'acide polylactique et dévolatilisation de la composition brute d'acide polylactique afin de produire une composition d'acide polylactique purifiée et une composition contenant du lactide n'ayant pas réagi ; d) soumission de la composition enrichie en méso-lactide et au moins une partie de la composition contenant du lactide non réagi à une purification comprenant au moins une étape de cristallisation afin de produire une composition enrich