Styrene-Butadiene Latex Blending as a Strategy to Mitigate Property Trade-offs in Paper Coatings

Abstract

Latex binders are the predominant binders in pigmented coatings for paper, and various latexes with different properties are selected depending on the target product. However, modifying latex binder properties to improve a particular coated paper property often introduces trade-offs in other properties. This study investigated the potential of latex blending to mitigate coated-paper property trade-offs compared with single-latex formulations, focusing on surface and optical properties, as well as ink absorption, and print-mottle-related behavior. Six styrene–butadiene (SB) latexes with different glass transition temperatures (T_g) and particle sizes were used, and coated paper property pairs exhibiting trade-off behavior were identified using single-latex formulations. Subsequently, coated papers were prepared with seven binary latex blends, and their trade-off performance relative to the single-latex formulations was evaluated using a trendline-based trade-off analysis. The results showed that low–high T_g blends provided improved trade-off performance compared with the single-latex formulations. The coexisting binder morphology in these blends enabled higher gloss with a smaller penalty in the trade-off properties, maintaining higher light-scattering efficiency and improving print-mottle-related behavior. The findings of this study indicate that latex blending has the potential to mitigate coated paper property trade-offs and provides a practical approach for optimizing coated paper performance.