The Influence of Pigment Particle Shape on the In-plane Tensile Strength Properties ofKaolin-based Coating Layers, 2006 TAPPI Advanced Coating Fundamentals Symposium
The mechanical properties of paper coating layers are very important in converting and printing operations.These include stiffness, resistance to fold cracking, dusting and pick resistance. In this study we have preparedunsupported coating layers and measured the in-plane tensile strength as a function of the kaolin particle shapefactor.
The results show that for pigments having a similar particle size by sedimentation, in-plane tensile strength ofthe coating layer increases as the shape factor of the clay particles increases. Conversely, the elongation tobreak decreases. These observations are interpreted in terms of the microstructure of the coating layers. A newobservation is that there exists a critical latex level above which the elongation behaviour of the layer changes.This coincides with the typical latex levels used in offset coatings and suggests that the majority of latex in acoating exists in a bound state.
The Influence of Pigment Particle Shape on the In-plane Tensile Strength Properties ofKaolin-based C