Scott Internal Bond

Measurement Mechanism

Laboratories perform the assessment by applying double coated adhesive tape to both sides of a test specimen which is then clamped between a base plate and a pendulum weight. Impact force from the swinging pendulum separates the fibres in the Z-direction of the board, allowing the device to register the total energy absorbed during the rupture process. Analysts interpret the results in units of kilojoules per square meter, providing a data point that dictates how much tension a substrate withstands before failure occurs at the weakest layer.

Variability in fibre orientation or inconsistent sizing between plies directly alters the recorded energy dissipation. Low results indicate that the internal structure lacks sufficient cohesion, while excessively high values sometimes point toward over-engineered bonding agents that might interfere with coating absorption or foldability. Operators frequently adjust the starch spray levels or refine the pulp drainage rates at the wet end of the machine to maintain specific target ranges for this property.

Industry Application

Quality assurance protocols treat the measurement as a primary metric for validating structural integrity in heavy duty cartons and liquid packaging board. Converters specify required ranges to prevent surface lifting or picking during the transfer of tacky inks, especially when run on presses with high mechanical grip. Maintaining consistent levels protects the integrity of the substrate against the peeling forces exerted by the stripping process in die cutting stations.

A stable internal bond prevents mechanical separation at the crease line under the stress of rapid forming and final container sealing.