Meaning
Separation of two bonded surfaces occurs when the mechanical stress applied exceeds the bond strength at the interface. This adhesive peel failure is characterized by the clean removal of the adhesive from the substrate without leaving residue or damaging the base material. It indicates that the intermolecular forces at the joint are weaker than the internal cohesive strength of the adhesive itself.
Moulders identify this state during testing to verify that surface preparation or resin compatibility meets the requirements for a specific assembly.
Bond Integrity
Chemical compatibility between the adhesive and the polymer determines the durability of the union. Low surface energy in resins like polypropylene often leads to adhesive peel failure unless a primer or plasma treatment modifies the interface. The bond relies on secondary forces such as van der Waals interactions or hydrogen bonding which must be established during the curing or setting stage.
When these forces are absent, the assembly cannot withstand the operational loads required for the end use.
Separation Mode
Brittle or ductile behavior during the pulling process defines the way the joint gives way. A rapid crack propagation usually signals adhesive peel failure in rigid thermoset systems. Flexible films might exhibit a steady resistance before the bond breaks.
Interface Condition
Presence of contaminants like mould release agents or oils prevents the adhesive from wetting the surface. This blockage is a primary cause of adhesive peel failure in high volume production environments. Consistency in the cleaning process ensures that the contact area remains receptive to the bonding agent.
