Quantifying Surface Energy Values on Polyolefin Packaging Materials
Polyolefin surface energy quantification relies on standardized liquid titration or goniometry to secure ink adhesion and lamination bond strength across runs.
Wu Harmonic Model
Surface Energy
Surface thermodynamic calculation calculates the polar and dispersive components of surface energy from contact angle measurements of known liquids. Applying the Wu harmonic model provides accurate results for low-energy polymer surfaces used in packaging and lamination. It separates the total surface tension into polar and dispersive forces to predict how well a substrate will accept a specific adhesive.
Interfacial Tension
Using harmonic means to combine the components of different materials allows the formula to estimate the interfacial tension between the substrate and the coating. This is especially useful for co-extruded films where the interface between layers must be engineered to prevent delamination during converting. High surface matching leads to low interfacial energy, which translates to a high bond strength at the molecular level.
Adhesion Analysis
Analyzing the surface using this mathematical approach helps converters select the best treatment methods and coating formulations for their plastic films. The formulation provides higher accuracy for polymer melts and organic coatings compared to older models that rely on geometric means. By adjusting the corona treatment or primer chemistry based on the model’s predictions, manufacturers can reduce the risk of laminate failure in demanding barrier applications.
This predictive accuracy helps technical teams formulate custom primers that align with the specific chemical composition of incoming polymer batches.