Patent ID: 9023141
Filing Date: 2015-05-05
Classification: C09D

Abstract:
1. A process for making an aqueous pigment dispersion comprising the steps of: (a) grinding a mixture comprising a pigment, one or a combination of coating agents, a grinding agent and a vehicle, wherein said grinding agent is insoluble in said vehicle and soluble in water, and said coating agents contain an ionizable moiety and have a structure of formula (I): (b) washing with an aqueous medium to remove said grinding agent to form a press cake; and (c) adding an aqueous vehicle, adjusting the pH to ionize said ionizable moiety on said coating agents, and dispersing said press cake from step (b), in this order or any other workable orders, to form a dispersion; wherein each M wherein Ar 1 and Ar 2 are independently C 6 -C 40 aryl; Y is CR 3 R 4 , S, S(O) or a straight bond; R 3 and R 4 are independently H or C 1 -C 9 alkyl; each M 2 is COOH, or two M 2 groups can be taken together with the carbon atoms they are bonded to form a cyclic anhydride; and each m is independently an integer from 2 to 4.