Abstract: The invention relates to a process and an apparatus for pelletizing polymer melts comprising blowing agent in a pelletizing chamber through which a liquid flows, its pressure being above the ambient pressure. In a first step, the polymer melt is injected into the pelletizing chamber, in a second step the polymer melt is cut via a cutting apparatus into individual pellets and, in a third step, the pellets produced in the pelletizing process are discharged with the liquid from the pelletizing chamber and are then isolated from the liquid.

Abstract: A process for producing polymer particles by polymerizing liquid droplets in a gas phase by metering a liquid comprising at least one monomer from at least one feed by means of a multitude of bores into a reaction chamber comprising the gas phase, wherein ratio of length of the feed to greatest diameter of the feed in the region of the multitude of bores is at least 10.

Abstract: A process for producing polymer particles by polymerizing liquid droplets in a gas phase by metering a liquid comprising at least one monomer from at least one feed by means of a multitude of bores into a reaction chamber comprising the gas phase, wherein ratio of length of the feed to greatest diameter of the feed in the region of the multitude of bores is at least 10.

Abstract: The invention relates to a process and an apparatus for pelletizing polymer melts comprising blowing agent in a pelletizing chamber through which a liquid flows, its pressure being above the ambient pressure. In a first step, the polymer melt is injected into the pelletizing chamber, in a second step the polymer melt is cut via a cutting apparatus into individual pellets and, in a third step, the pellets produced in the pelletizing process are discharged with the liquid from the pelletizing chamber and are then isolated from the liquid.

Abstract: Polyamides, oligomers thereof or mixtures thereof, if required with further reaction products, are prepared by reacting aminonitriles or dinitriles and diamines or a mixture containing aminonitrile, dinitrile and diamine, and, if required, further polyamide-forming monomers and/oligomers with water in a reactor (1) having a vertically oriented longitudinal axis, by a process in which, in the reactor (1), the reaction product is removed from the bottom and ammonia formed and any further low molecular weight compounds formed and water are taken off via the top (2), wherein the reactor (1) has at least two chambers (4) arranged one on top of the other in the longitudinal direction, the chambers (4) being separated from one another by liquid-tight trays (5), each chamber (4) being connected by a liquid overflow (6) to the chamber (4) directly underneath and a liquid product stream being taken off by the liquid overflow (6) of the lowermost chamber (4), the gas space (7) above the liquid level in each chambe