Surface Energy Measurement Methods for Polyolefin Packaging Films
Polyolefin surface energy audits require OWRK polar component tracking and dyne fluid validation to prevent lamination delamination and slip agent masking.
Dispersive Polar Surface Energy
Surface Tension
Intermolecular forces divided into separate components explain the wetting behavior of liquids on solid packaging substrates. The total surface energy of a polymer film comprises dispersive polar surface energy, representing the individual contributions of non-polar dispersion forces and polar dipole-dipole interactions. Measuring these distinct components involves applying liquids of known polar and dispersive values, such as water and diiodomethane, to calculate the contact angles.
These measurements reveal whether a film can be wetted by a specific ink formulation.
Polar Interaction
Chemical bonds at the interface depend on the alignment of polar groups in both the liquid phase and the solid substrate. When the polar component of the substrate matches the polar component of the ink, adhesion improves because of hydrogen bonding. The dispersive component relies on weaker Van der Waals forces, which are universal but less effective for high-durability bonds.
Adjusting the ratio of these forces allows converters to optimize the wetting of water-based coatings.
Adhesive Performance
Mismatches between the surface energy components of the film and the adhesive lead to failures like de-lamination. A high dispersive component alone cannot guarantee good bonding if the polar component is too low to interact with the polymer adhesive. Testing these components separately ensures that treatment levels on the film remain within the required specification for multi-layer lamination.