ABSTRACT
This chapter discusses the physico-chemical concepts required for better understanding of the interaction of fluids with paper and shows with experimental data how theory may be used to address various technological issues of interest to the paper and ink maker. Surface roughness on a dimension greater than atomic sizes results in reduced area of contact and hence reduced adhesion strength. Excessive capillary penetration of an adhesive may result in weak adhesion as the adhesive is absorbed into the substrate and away from the bonding interface. The use of so-called “dyne solutions” for monitoring the surface tension of paper is based on the arguments of Zisman. In this approach, the alcohol-water or lactic acid-water solutions are used to determine the Zisman critical surface tension. The ink formulator must recognize the variability of the surface chemistry of paper and design ink formulations which are both appropriate for the job at hand and which are forgiving to variations in paper surface chemistry.
