Sulzer Chemtech Ag

Purac Biochem Bv

Sulzer Management Ag

François Loviat

Manfred Stepanski

Gerrit Gobius Du Sart

Liborio Ivano Costa

Siebe Cornelis De Vos

Andrzej Kuszlik

Robert Edgar Haan

Daniel Dünnenberger

Daniel Dunnenberger

A static devolatilisation apparatus () adapted for devolatilising a viscous liquid () comprising a volatile component is disclosed. The apparatus () comprises a phase separation chamber () in an upper region () for treating the viscous liquid () in a first devolatilisation step to form a first devolatilised viscous liquid (), and a distributor sub-unitis located below the phase separation chamber () and above a lower sump region (). The sub-unit () has a second discharge region () embodied such that it is contacted by the first devolatilised viscous liquid (), and the region () has a surface () embodied such that the first devolatilised viscous liquid () is treated in a second devolatilisation step. The present invention further relates to a process to devolatilising a viscous liquid using the apparatus () and also to the use of the apparatus () in the devolatilisation of polymer melt or solution.

Devolatilisation apparatus and a process for use thereof

A method for the removal of an ester (') from a vapor mixture (&#x2032;) containing the ester (&#x2032;) is disclosed. The method comprises the steps of by bringing the vapor () mixture (&#x2032;) into contact with an aqueous solution (&#x2032;) containing the acid (&#x2032;) corresponding to the ester (&#x2032;), wherein a portion of the ester (&#x2032;) is dissolved in or otherwise transferred to the aqueous solution (&#x2032;), and the aqueous solution (&#x2032;) is after the contact led in a circulation (), the aqueous solution (&#x2032;) is processed in the circulation () in a process comprising: a heating step (), a () reaction step () having a residence time and a temperature, a cooling step (), wherein the heating step () precedes the reaction step (), the reaction step () precedes the cooling step (), and the residence time and the temperature in the reaction step () are sufficient to substantially reduce the content of the ester (&#x2032;) in the aqueous solution (&#x2032;). The invention further () relates to an apparatus () for carrying out said process. The present invention further relates also to the use of the apparatus () in the method of the invention, preferably in the production of a lactide (&#x2032;) or a polylactic acid polymer (&#x2032;).

Method for removing an ester from a vapor mixture

A method for manufacturing poly(2-hydroxyalkanoic acid) included the steps of a) mixing a cyclic diester of a 2-hydroxyalkanoic acid and a polymerization catalyst, b) polymerizing the cyclic diester to form poly(2-hydroxyalkanoic acid) in liquid phase, c) adding a phosphoric acid ester as a catalyst deactivating agent to the liquid phase, d) applying a devolatilization step to the liquid phase, and e) allowing the poly(2-hydroxyalkanoic acid) to solidify. The catalyst deactivating agent is added after the devolatilization step is applied. The method results in an improved melt stability of the manufactured polymer.

Poly(2-hydroxyalkanoic acid) and method of its manufacture

A method for manufacturing poly(2-hydroxyalkanoic acid), preferably a poly(lactic acid), is disclosed. The method comprises the steps of: mixing a cyclic diester of a 2-hydroxyalkanoic acid and a polymerization catalyst, polymerizing the cyclic diester to form poly(2-hydroxyalkanoic acid) in liquid phase, adding a peroxide-based compound as a catalyst deactivating agent to the liquid phase, applying a devolatilization step to the liquid phase, and allowing the poly(2-hydroxyalkanoic acid) to solidify, characterized in that an end-capping agent is added to the poly(2-hydroxyalkanoic acid) in the liquid phase. The present invention also relates to a poly(2-hydroxyalkanoic acid), preferably a poly(lactic acid), obtainable with said method characterized in that the polymer has a Mn abs ranging between 10000 and 250000 g/mol, preferably between 20000 and 85000 g/mol.

Method for manufacturing poly(2-hydroxyalkanoic acid), and the poly(2-hydroxyalkanoic acid) obtainable thereby

Disclosed is a method to prepare a polylactic acid comprising the steps of performing a ring opening polymerization using a catalyst and either a catalyst killer compound or an endcapping additive to obtain a raw polylactic acid of MW greater than 10,000 g/mol, purifying the raw polylactic acid by removing and separating low boiling compounds comprising lactide and impurities from the raw polylactic acid by devolatization of the low boiling compounds as a gas phase stream, and purifying the lactide from the devolatization and removing the impurities from the gas phase stream of evaporated low boiling compounds by means of crystallization by desublimation from the gas phase, wherein the lactide is purified and the removed impurities include a catalyst residue and a compound containing at least one hydroxyl group such that the purified lactide is then polymerized by feeding it back into the ring opening polymerization. The invention further relates to an apparatus for carrying out the method comprising a polymerization reactor for performing a ring opening polymerization to obtain a raw polylactic acid, a devolatization apparatus for separating low boiling compounds comprising lactide and impurities from a raw polylactic acid, and a crystallization apparatus for purifying a lactide and removing impurities by means of a desublimation and a crystallization in the same crystallization apparatus.

Growing community of inventors

Sennhof, Switzerland

François Loviat