Ciba-geigy Corporation

Alistair B Boyd

George H Robertson

Robert L Rooney

Michael Mordente

The present invention provides a process for the production of a metallized azo pigment having the formula ##STR1## in which R and R.sub.1, independently, are hydrogen, halogen or alkyl; X.sub.1 is SO.sub.3.sup..crclbar. or CO.sub.2.sup..crclbar. ; and M is Ca, Sr, Mn or Ba; comprising coupling, at a pH value below 7.0, a diazotized amine of formula ##STR2## in which R, R.sub.1 and X.sub.1 have their previous significance, with a coupling component of formula ##STR3## to produce an azo dyestuff having the formula ##STR4## in which R, R.sub.1 and X.sub.1 have their previous significance, and Y is an alkaline earth metal or ammonium ion; and laking the dyestuff of formula IV during or after its production with one or more salts of a metal M wherein M has its previous significance. Also disclosed is a new modification of a pigment of formula I.

Production of pigments

A process for the production of a non-dusting pigment composition by contacting an aqueous dispersion of an organic pigment with

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Paisley, United Kingdom

Alistair B Boyd