Peeling Resistance
Interlaminar adhesion in multi ply board is evaluated by applying a peeling force to a split specimen. Laboratories use the double cantilever beam test to measure the energy required to separate the layers of a laminated board. This procedure isolates the adhesive strength of the interface from the bending stiffness of the outer plies.
Loading Protocol
Specimen preparation involves creating a pre crack at one end of the laminated board sample. Testing machines apply a tensile load to tabs attached to the split ends, pulling them apart at a constant rate. Recording the force and the displacement of the crosshead allows the technician to plot the energy consumption.
This plot shows the resistance of the adhesive bond as the crack propagates along the length of the beam.
Adhesion Evaluation
Results from the double cantilever beam test help packaging engineers select the correct adhesive chemistry for specific board surfaces. A low energy value indicates that the laminating adhesive is prone to failure during subsequent folding and converting processes. High stiffness in the paperboard plies can complicate the test, requiring numerical corrections to isolate the true adhesion.
Moisture and temperature during the test must be tightly controlled to prevent elastic changes in the board.
