Patent ID: 6602335
Filing Date: 2003-08-05
Classification: C09B,C09D

Abstract:
A method for self-dispersing a pigment in an aqueous solution, said method comprising:(a) providing said pigment, said pigment distinguished in having an azo group and either a &bgr;-diketo structure or a hydroxyl group, each conjugatively associated with said azo group; (b) treating a surface of said pigment with a base having sufficient strength to generate a negative charge on said pigment; and (c) reacting said negatively charged pigment with either (1) a first hydrophilic molecule containing at least one functional group comprising a carbonâ€”carbon double bond and a carbonyl that is alpha to the carbonâ€”carbon double bond which reacts via addition to form a hydrophilic group on said pigment or (2) a second hydrophilic molecule containing at least one functional group selected from the group consisting of anionic functional groups, cationic functional groups, and zwitterionic functional groups and at least one suitable leaving group which reacts via substitution to form a hydrophilic group on said pigment.