Abstract: There is described a process for preparing a biodegradable polyester from an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid and a diol where in a first reaction step the aromatic acid is esterified with the diol, and in a second reaction step the aliphatic acid is added to the reaction mixture. Furthermore, there is described an apparatus for carrying out this process.

Abstract: A process for reducing the amount of hydroxyl-end-groups of a polyester, wherein the polyester is prepared from at least one dicarboxylic acid and at least one dihydroxy alcohol, and at least one additive selected from the group consisting of carboxylic acid anhydride and mono-isocyanate, and wherein the additive is added during a step of prepolycondensation and/or during a step of polycondensation and/or after a step of polycondensation.

Abstract: The present application relates to a process for preparing polyesters comprising reacting a dicarboxylic acid with butanediol in the presence of a catalyst, wherein in the process an aluminosilicate is present, as well as the use of aluminosilicates in such a process.

Abstract: The present invention relates to a method for the production of polyamide 6 with low extract content and a device for it. Here, a melt of non-extracted polyamide 6 is cleaned from monomer and oligomers in a degasification device in vacuum, wherein the vapor being withdrawn from the degasification device by the vacuum generation device is cleaned from monomer, oligomers and optionally water at first in a direct condenser which is operated with liquid ?-caprolactam and subsequently in a pre-separator which is cooled with a coolant, before it reaches the vacuum generation device. A particularly preferable variant of the method envisages the usage of the melt of polyamide 6 with low extract content so prepared in a direct process of spinning into textile fibers and/or filaments.

Abstract: A process for the recovery of ?-caprolactam from extract water of polycaprolactam obtained by hydrolytic polymerization, wherein the extract water is concentrated, subsequently contained oligomers are depolymerized, non-depolymerizable impurities are separated, water and low-boiling impurities are removed, wherein for adjusting the purity of the recovered ?-caprolactam and the energy consumption used for the process a part of the product is removed from the process as intermediate products.