High-Strength Coating Binders Based on Molecular Design of Styrene-Butadiene-Acrylonitrile Latices

摘要

Optimizing raw materials utilization is currently high priority for nearly every coated papermill. An effective wayrnto achieve this is by improving coating latex strength in order to maximize binding strength without sacrificing otherrncritical coated paper properties. Previous studies have demonstrated how latex emulsion features, latex chemistry,rnand solubility influence the picking strength of paper coatings. In this paper, we demonstrate how intrinsic polymerrnphysics of a latex influence coated paper -offset ink interactions, effectively increasing the passes to fail (strength)rnof a paper coating. A novel approach developed a correlation between molecular weight between chain crosslinksrn(Mc) of polymeric latex and coated paper-ink performance, with the intent that in the future we can predict latexrnperformance in a formulated coating from selected latex film testing and its viscoelastic properties. Examples arernshown using experimental polymers made with a modified emulsion polymerization process that changes polymerrnarchitecture and Mc, the latter estimated from dynamic viscoelasticity measurements of latex films. Paper coatingrnapplication methods included laboratory drawdowns, CLC and papermill trials. Results indicated that there is anrninfluence of the latex film viscoelasticity, and therefore Mc, in ink setting onto papers coated with formulationsrncontaining the latex. We found that latex films with relatively lower storage modulus and higher tangent deltarnincreased pigmented coated paper strength. Differences in viscoelasticity were attributed to molecular weight (Mc)rnbetween polymeric chain crosslinks. A high Mc of a latex correlates with improved passes to fail in the laboratoryrnpaper-ink interaction test.