Abul Iqbal

Some aspects of organic pigments

Organic pigments are traditionally used in the mass colouration of plastics and synthetic fibres, and in surface coatings such as paints and inks. More recently, they have also found increasing use in a number of high technology industries. Commercial pigments must satisfy many performance criteria, which in turn are determined by their molecular, solid state and particle surface characteristics. This review highlights some of the important aspects of organic pigments which are of importance to both producers and users.

Latent pigments activated by heat

Organic pigments are used as colourants in paints, plastics, printing inks and in the electronics industries. They can be distinguished from dyes in that they are insoluble. Whereas dyes readily dissolve to give homogeneous coloration, the application of organic pigments frequently requires a time- and energy-consuming dispersion step. Here we report a method for converting a pigment into a suitable precursor, a ‘latent’ pigment. Like a dye, the latent pigment is readily soluble or homogeneously dispersible in the application medium, and on subsequent thermal treatment it can be transformed in situ to the parent pigment.