Dynamic water penetration behavior of top coating color and its effects on structure properties of double-coated layer

The relationship between the dynamic water penetration behavior of top coating color and double-coated paper properties, including pore structure, surface roughness, gloss, and surface latex content, was investigated. Top coating was applied onto the precoated paper prepared using different pigment types, thereby having different pore structures. To investigate the effect of dwell time on pore structure and surface latex content, coating speed and the distance between two coating heads of a laboratory coater were adjusted. As the number of pores of the precoated layer increased, the amount of water that penetrated the precoated paper increased, regardless of low shear viscosity of the top coating color. The relative pore ratio and surface properties of the top coated layer were proportional to those of the precoated layer. A UV absorbance analysis was conducted to examine latex binder migration. The latex content on the surface of the coating layer was mainly affected by the dwell time to the dryer after coating.