PIGMENTED WAX DISPERSION AND METHOD FOR PREPARING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide pigmented particle dispersions that have narrow particle size distributions and small particle diameters, and are stable in a solid ink medium.SOLUTION: A process for preparing a pigmented wax dispersion includes: (a) melting and mixing a dry pigment with at least one wax to form a pigment concentrate which contains at least 25 wt.% of pigment; (b) milling the pigment concentrate of the step (a) to form a milled pigment concentrate; and (c) combining the milled pigment concentrate of (b) with water and dispersing the same to form a pigmented wax dispersion comprising a plurality of pigmented wax particles having a pigment core surrounded by a wax shell. The pigmented wax particles exhibit a particle size distribution of from about 150 nanometers to less than about 300 nanometers, the melting and mixing in the step (a) and the milling in the step (b) are done in an immersion media mill; and the combining in the step (c) is done using a piston homogenizer.