Batch production of polymer melt, e.g. polyester, involves polycondensation in a reactor with a loop containing a filter through which the melt is passed at least three times during the reaction

摘要

Batch production of polymer melt involves passing all the melt from a polycondensation reactor through a filter in a loop at least 3 times during the reaction, the required filter surface being controlled by the amount of filter cake and the resulting pressure loss in such a way that a specified pressure loss is not exceeded and the free, active filter surface is kept constant. A process for the batch production of a polymer melt with filtration, in which the polymer melt is taken from a polycondensation reactor (5) with the aid of a pump (3), immediately passed through a filter (6) and then either recycled to the reactor or transferred to a granulator. In this process, the whole of the melt in the reactor is passed through the filter at least 3 times during the polycondensation reaction and the required filter surface is controlled by the amount of filter cake on the filter and the resulting pressure loss in such a way that a specified limiting value of pressure loss is not exceeded and the free, active filter surface is kept almost constant, while the viscosity of the product increases continuously from 0.1 Pa.s to not more than 1500 Pa.s.