Abstract: The present invention relates to a method of preparing a modified colored pigment comprising a pigment having attached at least one organic group. The method comprises the step of combining, in any order, a) a solution of an organic colorant in a solvent, b) at least one aromatic amine comprising the organic group, c) at least one diazotizing agent, d) an aqueous medium, e) optionally at least one acid, and f), optionally at least one second solvent, to form the modified colored pigment.

Abstract: Colored pigments having one or more desired parameters and/or properties are described. These parameters and/or properties include: a) a particles size of from about 10 nm to about 300 nm; b) an accusizer number of less than 1010 particles/ml of dispersion at 15% solids which are greater than 0.5 micron; c) a filterability such that when in a liquid medium, 100 ml having 10% solids of the colored pigment filters through a 3 micron nylon absolute filter; d) a colored pigment purity of greater than about 80%, based on extractable material; and/or e) a stability such that the above-described properties do not change by more than 50% at 25 degrees C for at least one week. Colored pigments having at least one organic group and having one or more of the above-described characteristics is also described as well as a process for preparing surface-modified colored pigments.

Abstract: Colored pigments having one or more desired parameters and/or properties are described. These parameters and/or properties include: a) a particles size of from about 10 nm to about 300 nm; b) an accusizer number of less than 1010 particles/ml of dispersion at 15% solids which are greater than 0.5 micron; c) a filterability such that when in a liquid medium, 100 ml having 10% solids of the colored pigment filters through a 3 micron nylon absolute filter; d) a colored pigment purity of greater than about 80%, based on extractable material; and/or e) a stability such that the above-described properties do not change by more than 50% at 25 degrees C. for at least one week. Colored pigments having at least one organic group and having one or more of the above-described characteristics is also described as well as a process for preparing surface-modified colored pigments.

Abstract: A process to purify and classify a dispersion containing stabilized particles having counterions and ions as well as free species is disclosed. The solution may comprise an aqueous media, a solvent media, or a combination of both and can include more than one type of aqueous and/or solvent solutions. The process includes at least the steps, in any order, of substantially removing the particles having sizes above about 1 micron, preferably above 0.5 micron; substantially removing the free species; and exchanging at least a portion of the counterions that are a part of the stabilized particles. The process disclosed is especially useful in purifying dispersions where the ionic stabilized colloidal particles are carbon black having attached organic groups comprising at least one ionic group, or at least one ionizable group, or mixtures thereof.