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.
Penetrometer Compressibility
Surface Deformability
Deformability under localized load represents an important property of paper and board surfaces during printing or finishing operations. The measure of penetrometer compressibility describes the depth of penetration of a probe into the substrate under a specified force. This metric helps in evaluating the softness and compliance of the board surface.
Mechanical Assessment
Testing equipment applies a controlled weight to a metal tip that contacts the paper surface to measure the resulting displacement. When penetrometer compressibility is high, the substrate deformability allows the paper to conform to the printing plate or gravure cylinder under lower pressure. This behavior helps in achieving full ink transfer on rough surfaces, reducing the need for high printing forces that can crush the paperboard’s internal structure.
Maintaining uniform compressibility across the web prevents uneven print density and mottle.
Fiber Structure
Refining of the pulp and the addition of mineral fillers during papermaking influence how the surface responds to pressure. Dense, heavily calendered boards show low penetrometer compressibility, while bulky sheets with less refining remain more compressible. Packaging materials like folding boxboard are engineered with high bulk to maintain stiffness while providing sufficient surface compressibility for clean foil stamping.
Measuring these variations ensures that converters can set appropriate impression pressures on their production lines.