Abstract: A method for removing compounds in the gaseous aggregate state from PLA-containing products in the viscous aggregate state by means of a thin-film evaporator. The compounds may be present in the liquid or solid aggregate state in the products under standard conditions. The invention further relates to a polylactide resin prepared in accordance with the method of the invention.

Abstract: A method for removing compounds in the gaseous aggregate state from PLA-containing products in the viscous aggregate state by means of a thin-film evaporator. The compounds may be present in the liquid or solid aggregate state in the products under standard conditions. The invention further relates to a polylactide resin prepared in accordance with the method of the invention.

Abstract: In a practicable continuous or batchwise process for the preparation of a crystallizable polylactic acid mixture, lactic acid may be polycondensed to yield an oligomer, which may then be depolymerized to yield a crude lactide. The crude lactide may be purified to yield a pure lactide, wherein fractionation may be carried out in the purification into an L- or D-lactide-rich fraction and also a meso-lactide-rich fraction. Subsequently a separate ring-opening polymerization of the resulting lactide fractions can be carried out. The individual polylactic acid batches or streams generated by the ring-opening polymerization may then be mixed. The present disclosure further relates to apparatuses for carrying out such processes and polylactic acid mixtures.

Abstract: The present invention relates to a device and also to a method for separating and recovering a cyclic diester, in particular dilactide or glycolide from polymer melts which include the cyclic diester as impurity. The device and also the method according to the invention allow recovery of the cyclic diester with a high yield and at the same time high purity.

Abstract: A method may facilitate the crystallization of granules of a crystallizable thermoplastic material in conjunction with removal of low molecular mass components contained in the thermoplastic material. The crystallizable thermoplastic material may have a crystalline melting temperature of at least 130° C. According to the method, a crystallization stage and a removal stage may be performed at different temperatures of the granules. Often the crystallization may occur at a lower temperature than the removal of the low molecular mass components. In the crystallization and removal stages, a flow of gas may pass countercurrent to a direction along which the granules are conveyed. Further, example devices disclosed herein may be utilized to perform the exemplary methods disclosed herein.

Abstract: In a practicable continuous or batchwise process for the preparation of a crystallizable polylactic acid mixture, lactic acid may be polycondensed to yield an oligomer, which may then be depolymerized to yield a crude lactide. The crude lactide may be purified to yield a pure lactide, wherein fractionation may be carried out in the purification into an L- or D-lactide-rich fraction and also a meso-lactide-rich fraction. Subsequently a separate ring-opening polymerization of the resulting lactide fractions can be carried out. The individual polylactic acid batches or streams generated by the ring-opening polymerization may then be mixed. The present disclosure further relates to apparatuses for carrying out such processes and polylactic acid mixtures.

Abstract: The present invention relates to a method for the production of cyclic carboxylic acid esters, in particular intramolecular lactones, such as e.g. dilactide, the production of these cyclic esters from oligomeric carboxylic acids being effected by cyclizing depolymerization. During this reaction, a condensation product of these oligomeric carboxylic acids is produced as by-product, i.e. a mixture of higher-molecular oligomeric carboxylic acids which are hydrolyzed in a further step and hence recovered. This hydrolysate can be added again to the cyclizing depolymerization which is implemented in the first step.

Abstract: The present invention relates to a device and also to a method for separating and recovering a cyclic diester, in particular dilactide or glycolide from polymer melts which include the cyclic diester as impurity. The device and also the method according to the invention allow recovery of the cyclic diester with a high yield and at the same time high purity.

Abstract: The present invention relates to a method for the production of cyclic carboxylic acid esters, in particular intramolecular lactones, such as e.g. dilactide, the production of these cyclic esters from oligomeric carboxylic acids being effected by cyclising depolymerisation. During this reaction, a condensation product of these oligomeric carboxylic acids is produced as by-product, i.e. a mixture of higher-molecular oligomeric carboxylic acids which are hydrolysed in a further step and hence recovered. This hydrolysate can be added again to the cyclising depolymerisation which is implemented in the first step.

Abstract: Disclosed is a test and test apparatus used to determine whether lactic acid is suitable for polymerization.