Rapid determination of coating per cent pigment from ink density and volume fraction

This report describes a method for predicting the per cent pigment in the cured film from the measured volume fraction of magnetic pigment particles in the ink and the ink density. A rapid electromagnetic method for measuring the volume fraction is described, and the volume fraction and density are related to the per cent pigment in the cured film by a material balance. Data showing the correlation of the TGA and the pigment content calculated from the ink density and volume fraction are presented for a typical recording disk ink.