Abstract
Coatings prepared from different blends of. plate-like kaolin pigment and prismatic precipitated calcium carbonate (PCC) were applied over both absorbent and nonabsorbent substrates. Surface morphology was characterized by gloss and roughness measurements, and X-ray photoelectron spectroscopy (XPS) was used to characterize the elemental composition of the surface layer. A small amount of, PCC added to the plate-like pigment coatings was found to disturb the surface structure. When more PCC was added, gloss increased on the nonabsorbent substrate, but it decreased on the absorbent substrate, accompanied by an increase in roughness. XPS showed that the surface latex content increased as the amount of prismatic PCC pigment increased in the plate-like kaolin coating. Adding PCC to the kaolin coating presumably produced more pathways by which latex particles could transfer to the surface. In addition, the PCC pigment at the surface could enhance latex spreading. Pigment shape and pigment blend affect both latex migration and spreading.