Process for preparing an aqueous ink jet printing ink

Abstract

A process for preparing an aqueous ink composition including 1) preparing a colorant concentrate; 2) preparing a colorant wax dispersion by (a) melting and mixing a dry colorant with at least one wax to form a colorant concentrate, wherein the colorant concentrate contains at least 25 percent by weight of colorant; (b) milling the colorant concentrate of step (a) to form a milled colorant concentrate; (c) combining the milled colorant concentrate of (b) with water and dispersing to form a colorant wax dispersion comprising a plurality of colorant wax particles comprising a colorant core surrounded by a wax shell, wherein the colorant wax particles exhibit a particle size distribution of from about 150 nanometers to less than about 300 nanometers; wherein the melting and mixing of step (a) and the milling of step (b) is done in an immersion media mill; and wherein the combining of step (c) is done using a piston homogenizer; and 3) blending the colorant wax dispersion with an aqueous ink vehicle and optional ink additives to form an aqueous ink composition; and filtering the aqueous ink composition.