Mercury Intrusion Porosimetry ISO 15901 Dynamic Surface Absorption Inspection Protocols
ISO 15901-1 porosimetry paired with dynamic sorption testing qualifies coating pore structures to prevent back-trap mottle and ink setting failures on press.
Kaolin Clay Platelets
Morphological Classification
Mineral particulates consisting of thin hexagonal lamellae act as functional fillers in coating formulations to improve surface smoothness and barrier properties. These kaolin clay platelets occupy the interstitial spaces between paper fibres during the wet end process or within a blade coating application. The high aspect ratio allows for tight stacking which effectively increases the tortuosity path for liquids or gases passing through the substrate.
Geometric alignment along the sheet surface reduces porosity while enhancing ink holdout and print gloss. Higher concentrations of these particles within a pigment binder matrix directly reduce the required volume of synthetic latex.
Application Mechanics
Coating engineers adjust the mechanical shear during the application of kaolin clay platelets to ensure proper orientation of the crystalline structure. Blades or rods exert force that forces these discs to lay flat against the base stock, thereby maximizing the total surface coverage. Proper leveling of the slurry inhibits mottle during subsequent printing cycles because the surface energy remains uniform across the entire sheet.
Uniformity in platelet distribution prevents ink vehicle penetration into the fibrous web.
Production Boundaries
Mineralogical purity dictates the brightness and abrasive potential of kaolin clay platelets in high speed converting operations. Processing involves strict filtration to remove oversized particles that cause scratching on metal print cylinders or polymer gravure rollers. Hardness values remain low enough to maintain compatibility with standard doctor blades used in paper finishing.
Controlled particle size distribution determines the specific opacity and light scattering efficiency of the final sheet surface. Dense packing of these platelets provides a stable foundation for high quality multicolour graphic reproduction.