Novel method for the evaluation of mechanical property of pigment coating layer and its application: Influence of spreading of latex binder on final properties of coating layer

The mechanical properties of paper coating layers are important in various processes and applications. Proper evaluation of the coating layers is essential for improving coating layer design. In this study, a novel method for the evaluation of the mechanical properties of coating layers was developed using a surface and interfacial characterizing analysis system (SAICAS) instrument, which has an important advantage of not requiring any special sample preparation process. Failure analysis results showed that the SAICAS method provided uniform and reproducible sectioning of the coating layer regardless of the layer's mechanical strength, indicating this is suitable for measuring the mechanical properties of coating layers. The influence of the spreading of latex binder on the final properties of the coating layer was examined and its correlations with structural properties were quantitatively analyzed. This was applied to analyze the mechanical, topographical, and optical properties of coating layers. The results showed that the peel strength and gloss were highly correlated with the spreading of latex. The chemical composition of S/B latex also influenced the peel strength of the coating layer. The transitions observed in the length distribution of pigment–binder interfaces greatly influenced the properties of the coating layer, including peel strength, gloss, and light-scattering efficiency.