Pigment dispersant and pigment composition, pigment dispersion and printing ink using the same

[0058] Manufacturing example 1

[0059] Add 15 parts of Pigment Red 166 to 300 parts of 99% sulfuric acid, and react at 25°C for 3 hours. The reaction liquid was poured into 3000 parts of ice water, stirred, filtered, and washed with a 2% aqueous hydrochloric acid solution. After making the obtained filter cake into a slurry with 700 parts of water, the pH was adjusted to 9 with sodium hydroxide. Then, it heated to 60°C, added 58 parts of 10% aluminum sulfate aqueous solution, stirred at 60°C for 1 hour, filtered, washed with water, and dried to obtain 18 parts of pigment dispersant (a). The average number of substituents for sulfonic acid groups is 1.8.

[0060] Manufacturing example 2

[0061] Change Pigment Red 166 to Pigment Red 214, at the same time, change the reaction temperature from 25°C to 30°C, and change 58 parts of 10% aluminum sulfate aqueous solution to 29 parts of 10% calcium chloride aqueous solution. 1 The same operation was performed to obtain 17 parts of pigment dispersant (b). The average number of substituents of the sulfonic acid group is 1.5.

[0062] Manufacturing example 3

[0063] Change Pigment Red 166 to Pigment Red 144, at the same time, change the reaction temperature from 25°C to 20°C, and change 58 parts of 10% aluminum sulfate aqueous solution to 33 parts of 10% ferrous sulfate aqueous solution. 1 The same operation was performed to obtain 18 parts of pigment dispersant (c). The average number of substituents of sulfonic acid groups is 1.2.