High Speed Ink Liquid Interface Dynamics in Ultra Light Coated Virgin Hardwood Graphic Papers
Ultra-light coated virgin hardwood papers demand sub-50nm coat pore radii to balance high-speed inkjet solvent absorption against hardwood fiber swelling.
Kaolin Clay Pigment Packing
Particle Arrangement
Spatial distribution of platy mineral particles governs the density and porosity of a dried paper coating layer. The term kaolin clay pigment packing refers to the geometric arrangement of these thin, hexagonal plates as they consolidate on the sheet surface. This structure determines the opacity and smoothness of the final paperboard.
Pore Structuring
Aligning clay plates during drying creates a tortuous network of capillary channels that slows down the absorption of fluid binders. In kaolin clay pigment packing configurations, the use of structured or hyper platy pigments prevents the tiles from stacking too tightly, preserving a high void volume. This open matrix maintains high light scattering and gloss while providing uniform ink absorption across the coated surface.
Controlling the particle size distribution allows paper mills to tailor the porosity for offset or gravure printing.
Coating Performance
Formulators adjust the ratio of kaolin to calcium carbonate to optimize the balance between coating smoothness and ink drying time. When kaolin clay pigment packing is too dense, the surface lacks the porosity needed for rapid ink solvent uptake, which can lead to ink smearing. Properly managed pigment structures produce a highly uniform print surface with high gloss and excellent ink holdout.