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METHOD FOR THE DIRECT PREPARATION OFLAKED AZO PIGMENTS

IP.com Disclosure Number: IPCOM000024099D
Original Publication Date: 1979-Oct-31
Included in the Prior Art Database: 2004-Apr-02

Publishing Venue

Xerox Disclosure Journal

Abstract

Disclosed is a direct method for preparing laked azo pigments which are useful in photoelectrophoretic systems. The process involves the preparation of an aqueous solution of a beta hydroxy naphthoic acid coupler in the form of a calcium salt, followed by coupling a diazotized amine into the solution and obtaining the calcium lake directly as a finely dispersed pigment. This process can be accomplished despite the low equilibrium solubility of the calcium salt of the beta hydroxy