Abstract: A process for producing a polycarbodiimide, comprising polymerizing a diisocyanate in the presence of a carbodiimidization catalyst in a reaction vessel in liquid phase at a temperature in the range of from 20 to 250° C., at a pressure in the range of from 20 to 800 mbar and in the presence of at least one inert gas, wherein the at least one inert gas is introduced into the liquid phase in the reaction vessel with a flow rate in the range of from 0.1 x/h to 100 x/h, x being the volume of the reaction vessel.

Abstract: The present invention relates to a process for preparing a polyamide based on dicarboxylic acids and diamines, comprising the following stages: A) providing an aqueous monomer mixture composed of dicarboxylic acids and diamines, where the molar ratio of dicarboxylic acids to diamines is adjusted such that, at the outlet of stage C), there is a molar deficiency of dicarboxylic acids or diamines of 1 to 10 mol %, based on the respective other component, B) transferring the aqueous mixture from stage A) into a continuous evaporator reactor in which diamines and dicarboxylic acids are converted at a temperature in the range from 100 to 370° C. and a pressure in the range from 1 to 50 bar, C) transferring the mixture from stage B) into a separator which is operated at a temperature in the range from 100 to 370° C.

Abstract: A process for producing a polycarbodiimide, comprising polymerizing a diisocyanate in the presence of a carbodiimidization catalyst in a reaction vessel in liquid phase at a temperature in the range of from 20 to 250° C., at a pressure in the range of from 20 to 800 mbar and in the presence of at least one inert gas, wherein the at least one inert gas is introduced into the liquid phase in the reaction vessel with a flow rate in the range of from 0.1 x/h to 100 x/h, x being the volume of the reaction vessel.

Abstract: The present invention relates to a process for the continuous production of thermoplastically processable polyurethane elastomers, by metering a polyisocyanate (A), a proportion of 1-80 equivalent%, based on the isocyanate group content of the polyisocyanate (A), of a compound (B) having an average of at 1.8-3.0 hydrogen atoms having Zerewitinoff activity, with an average molar mass of 450-5000 g/mol, and a proportion of 12-99 equivalent%, based on the isocyanate group content of the polyisocyanate (A), of a chain extender (C), into a self-cleaning twin-screw extruder whose diameter is 32-62 mm, which is operated at shear rates above 6000 s?1 and residence times of 1-20 seconds, and then bringing the mixture from the self-cleaning twin-screw extruder into a second apparatus in order to complete the reaction.

Abstract: The present invention relates to a process for preparing a polyamide based on dicarboxylic acids and diamines, comprising the following stages: A) providing an aqueous monomer mixture composed of dicarboxylic acids and diamines, where the molar ratio of dicarboxylic acids to diamines is adjusted such that, at the outlet of stage C), there is a molar deficiency of dicarboxylic acids or diamines of 1 to 10 mol%, based on the respective other component, B) transferring the aqueous mixture from stage A) into a continuous evaporator reactor in which diamines and dicarboxylic acids are converted at a temperature in the range from 100 to 370° C. and a pressure in the range from 1 to 50 bar, C) transferring the mixture from stage B) into a separator which is operated at a temperature in the range from 100 to 370° C.

Abstract: Process for continuous production of thermoplastically processable polyurethane elastomers with improved homogeneity, by metering a polyisocyanate (A), a proportion of from 1 to 80 equivalent %, based on the isocyanate group content of the polyisocyanate (A), of a compound (B) having an average of at least 1.8 and at most 3.0 hydrogen atoms having Zerewitinoff activity, with an average molar mass of from 450 g/mol to 5000 g/mol, a proportion of from 12 to 99 equivalent %, based on the isocyanate group content of the polyisocyanate (A), of a chain extender (C) having an average of at least 1.8 and at most 3.

Abstract: A process is described for reducing the residual monomer content in a liquid solution, mixture, melt, suspension or dispersion of a polymer by postpolymerization with addition of a redox initiator system at a reaction temperature appropriate to it and with an extremely short mixing time of the liquid system in the production reactor by metering—gradually, in portions or continuously—at least one of the redox initiator components required to initiate polymerization of the residual monomers over a period (metering time) which is from about 10 to 250 times the mixing time of the liquid system in said reactor.

Abstract: A process is described for effectively reducing the residual monomer content of an aqueous polymer dispersion by aftertreatment at atmospheric pressure or above with an initiator system comprising a) a hydroperoxide, hydrogen peroxide or a peracid, and b) an &agr;-hydroxy carboxylic acid, such as tartaric acid, or with a salt thereof.

Abstract: A reactor for chemical reactions, especially polymerization reactions, and in particular a reactor for emulsion, suspension, solution, bulk and/or precipitation polymerizations, which has a stirring mechanism, incoming and outgoing lines and a removable lid, and where both the stirring mechanism and incoming and outgoing lines are installed on the reactor floor. The novel reactor is quick and easy to open and clean and permits simple and rapid changeover of the installed stirring elements.

Abstract: A polymer dispersion is prepared by free radical polymerization of an aqueous monomer emulsion by a process in which the monomer emulsion is prepared continuously at the rate of consumption.

Abstract: At least one single-stage or multistage stirrer which produces not only a tangential flow component but also an axial flow field is used in a stirred-vessel reactor in connection with the preparation of polymers by liquid phase polymerization.

Abstract: A process for deodorizing and subsequently cooling dispersions or liquids comprisinga) passing steam through the dispersion or liquid to be cooled and held in a vessel (1), said dispersion or liquid being caused to foam up as a result,b) discharging the foam from the top section of the vessel via a nozzle (5) into an evacuated separation vessel (4), the foam being broken in the process,c) condensing the water vapor formed from the foam in a heat exchanger (8) and removing volatile organic components at the same time, andd) returning the broken foam to the vessel (1),in which the steps a) to d) are performed until the dispersion or liquid has been deodorized to the desired extent, wherein, after completion of the deodorization (in accordance with steps a) to d)), the hot dispersion or liquid is discharged from the bottom section of the vessel (1) through the nozzle (5) into the evacuated separation vessel (4), so that the dispersion or the liquid is cooled, the nozzle (5) and the evacuated separation vessel (4