Method of producing an azo pigment suitable for use in a gravure printing ink and azo pigments produced thereby

An azo pigment produced by treating 100 parts by weight of an azo pigment with:

• 1-30 parts by weight of an amine;
• 0.1-0.5 equivalents, based on said amine, of:
• (i) a fatty acid;
• (ii) a rosin or rosin derivative having a molecular weight of less than 2000;
• or
• (iii) a mixture of (i) and (ii);
• and
• 0.5-50 parts by weight of a carboxyl group-containing resin having a number average molecular weight in the range of from 2,000 to 150,000 and an acid value of at least 50.

A method for producing a pigment comprising:

• (a) diazotizing an aromatic amine,
• (b) reacting the diazotized aromatic amine with, in admixture, a coupling agent and a member selected from the group consisting of:
• (i) fatty acids of the formula R.sub.6 --COOH wherein R.sub.6 is alkyl of 6 to 24 carbon atoms,
• (ii) rosin and rosin derivatives of a molecular weight less than 2000, and
• (iii) mixtures of (i) and (ii), and
• (c) after completion of the coupling reaction of step (b), admixing 100 parts by weight of the reaction product with (iv) 0.5 to 50 parts by weight of a carboxyl group-containing resin having an acid value of at least 50 and a number average molecular weight of 2000 to 150,000 and (v) 1 to 30 parts by weight of an amine, said member (i), (ii) or (iii) being present in the amount of from 0.1 to 0.5 equivalents based on the amine.