Twin-Screw Extruder

摘要

A method for preparing an organic pigment dispersion, such as a flush pigment or ink product, comprises steps of introducing into a twin screw extruder a stable, water-borne pigment dispersion, an organic medium, and a destabilizing agent; mixing together the stable, water-borne pigment dispersion, the organic medium, and the destabilizing agent to produce a pigment flush phase and a water phase; and removing at least a part of the water phase. A twin-screw extruder for carrying out the flushing method has an addition and flushing zone, a water removal zone, and a zone for rinsing the crude organic pigment dispersion or flush with water and removing the rinse water. Additional materials may be added to form a finished pigmented product such as an ink product, masterbatch, or toner.