Structural Separation
Mechanical failure within paper substrates occurs when local stress forces the internal network of refined cellulose fibres to shift or pull apart. Interfiber bond dislocation reduces the internal ply strength of a sheet by compromising the hydrogen bonds that hold the fibre matrix in a coherent arrangement. Such damage prevents the substrate from resisting high peel forces during high speed converting operations.
Internal Integrity
Hydrodynamic shear during the papermaking process sometimes causes these micro-scale gaps when machine speeds exceed the drainage capacity of the wet end. High speed coating heads or aggressive adhesive application on packaging lines act upon the surface to pull the fibres away from their neighbours. This condition decreases the internal bond strength of the board and creates a weak point where delamination begins under moderate tension.
Excessive moisture levels in the sheet exacerbate the movement because water molecules interrupt the hydrogen bonding process between cellulose fibrils.
Quantification Metrics
Scott bond testing establishes the force required to rupture the internal structure of a substrate to verify if the fibre network maintains stability. Analysts measure this energy in joules per square meter to determine if the manufacturing process produces a stable enough board for lamination or folding. A high reading indicates superior internal cohesion while a low reading points to potential failure during automated processing.
Boards failing to meet specific resistance thresholds often suffer from board ply separation or surface picking during the printing cycle.
