Extrusion Coated Board Barrier Mechanics in High Humidity Converting
Extrusion coatings resist humidity until creasing strain shears polymer-fiber bonds, opening edge-wicking pathways that inflate converting scrap.
Interfacial Peel Strength
Adhesion Resistance
Quantifiable force per unit width required to separate two laminated flexible layers along their bonded boundary defines the mechanical integrity of multi-layer packaging structures. Expressed in newtons per fifteen millimeters, interfacial peel strength measures the resistance of heat seals and adhesive laminations against delamination. This property governs package seal integrity and pouch durability during transport.
Evaluation applies strictly to bonded flexible interfaces, becoming non-applicable when the backing substrate tears before the laminate bond yields.
Bond Separation
Testing protocols utilize a universal tensile tester pulling the bonded assembly at a constant angle of ninety degrees or one hundred eighty degrees at a standardized crosshead speed. Tensile stress concentrates at the crack tip, where energy dissipates through elastic deformation of the substrate film and viscoelastic deformation of the adhesive layer. Corona treatment levels and primer coating weights directly impact bond values across polymer films.
Insufficient drying of solvent-based adhesives leaves residual solvents that plasticize the interface, drastically reducing peel resistance under dynamic loading. Conversely, excessive crosslinking in solventless polyurethane formulations creates brittle interfaces that exhibit stick-slip failure during peel testing.
Testing Parameter
Controlled environmental conditioning at twenty-three degrees Celsius and fifty percent relative humidity ensures repeatable measurements across different production batches. Deviations in testing speed alter measured values due to the strain-rate sensitivity of polymer adhesives.
Quantifying Interfacial Metal Adhesion in Flexible Packaging Films
Quantify metal-to-polymer adhesion using ASTM F904 peel testing with EAA backing, targeting values above 60 N/m to ensure barrier stability during converting.