Adhesion Evaluation
Specialized materials testing machines evaluate the bonding strength of flexible laminates and coatings on paperboard substrates by pulling them apart under controlled conditions. The low angle peel test, usually performed at an angle of ninety degrees or lower, isolates the shear and peel stresses at the adhesive boundary. This method simulates the forces that occur when a consumer opens a sealed carton or when a pouch is subjected to internal pressure.
Test Execution
A motorized carriage holds the sample plate and moves it horizontally while a load cell records the tensile force required to strip the laminate from the paperboard. Keeping the angle low, often at fifteen or thirty degrees, minimizes the bending stress of the substrate and ensures that the measurement reflects the adhesive bond rather than the stiffness of the backing material. Recording software plots the peel force against the displacement distance to generate a detailed curve.
This curve helps identify variations in adhesive coverage or spots where the coating did not cure properly.
Failure Mechanism
Inconsistent test angles or fluctuating carriage speeds can introduce large errors in the force readings, rendering the results invalid. Maintaining rigid mounting and constant speed is therefore critical to achieving reproducible quality control data.
