Abstract: Printing inks are described which utilize a unique class of coloring agents which are the reaction products of free NCO group bearing resins and dyestuffs bearing reactive hydrogens. A novel class of such adducts which contain monocarboxylic acid residues are also described. These printing inks, which may also contain traditional pigments, find particular utility in letterpress or offset printing.

Abstract: The present disclosure is concerned with the preparation of permanent pigments from selected cationic dyes by precipitation from aqueous solution with complex heteropoly acids in the presence of selected amine color enhancing agents. Typical of the dyes is Color Index Basic Red 12, typical of the complex heteropoly acid is silicomolybdic acid and typical of the amine color enhancing agents are abietyl amine, cetyl pyridinium chloride and benzyl tri-n-alkyl ammonium chlorides. The pigments are disclosed to have superior cleanliness, brightness and transparency compared to the same pigments prepared without the amine color enhancing agent. These pigments are disclosed to have particular utility in printing inks such as components of process red for four color printing.