Process for the continuous fractionation of polymers

摘要

The invention relates to a process for the fractionation of polymers of high molecular and/or chemical nonuniformity to give fractions of low nonuniformity, which is characterised in that the polymer to be fractionated is dissolved in a one- or multicomponent solvent, and this solution (feed) is extracted continuously in countercurrent with the aid of a second liquid, the solvent component(s) in the feed and second liquid being selected so that a) the entire system of starting polymer and solvent component(s) has a miscibility gap at the operating temperature, b) the composition of the feed corresponds to a point outside this miscibility gap, and c)the second liquid has a composition such that the line connecting the feed and second liquid (operating line) passes through the miscibility gap. e