PROCESS AND APPARATUS FOR REMOVING IMPURITIES FROM POLYMERS

摘要

A continuous, preferably counter-current, extraction process that can be used to significantly reduce the concentrations of residual monomers, residual catalyst, undesired solvents, and other impurities in polymer compositions. The invention is particularly beneficial for extracting residual monomers and other impurities from viscous, sticky polymer solutions, such as solutions of PSAs and low cohesive strength polymer compositions that phase change during extraction (i.e., change from liquid to solid, or precipitate), in a continuous manner. The polymer composition can be extruted into an extraction solvent as fibers in a vertical extraction column, under conditions such that at least a portion of an impurity is extracted from the polymer into the extraction solvent.