Preparation of thermally stable dyes derived from diketopyrrolopyrrole pigment by polymerisation with polyisocyanate binder

Four thermally stable and solvent soluble dyes were prepared from diketopyrrolopyrrole pigment via an N-alkylation reaction. To improve the thermal stability of the dyes, a hydroxyl functional group that could react with blocked polyisocyanates was introduced into the dyes. The prepared dyes had absorption maxima near 500 nm, and the chromaticity diagrams of all synthesised dyes exhibited smaller x and y values than those of CI Pigment Red 254, indicating that the colour of the synthesised dyes was close to an orange shade. The dyes reacting with blocked polyisocyanates showed extremely high thermal stability compared with analogous dyes not reacting with polyisocyanates.