EFFECT OF POST-TREATMENT ON THE OPTICAL-PROPERTIES OF PLASTIC PIGMENT COATINGS

Experimental data are presented which demonstrate that the light-scattering coefficient of clay or calcium carbonate coatings containing plastic pigment can be enhanced considerably by inducing latex particle fusion through a heat treatment. The level of improvement depends on the plastic pigment particle size and amount. The fusion process is temperature-dependent and could probably be performed at commercial speeds. Other properties (gloss, smoothness, fluid absorption) are not significantly altered. The coatings develop some mechanical strength, but a binder would have to be added for offset printing.