Latex uniformity in the coating layer of paper

ATR-IR mapping was used to analyze the amount and uniformity of SB latex on the surface of coated paper. It was found that laboratory coatings containing CMC had a higher surface latex content and better uniformity than those without CMC. In calcium carbonate pilot coatings, surface latex content increased and uniformity improved as coat weight increased. However, back-trap mottle was greater in the samples with higher coat weights. In all pilot coatings, the surface latex content was 1-2 parts lower than in the coating color formulation itself. IR surface analysis and z-directional latex distribution analysis suggest that during coating layer consolidation the latex moved towards the base paper more than the pigment.