High Speed Ink Liquid Interface Dynamics in Ultra Light Coated Virgin Hardwood Graphic Papers
Ultra-light coated virgin hardwood papers demand sub-50nm coat pore radii to balance high-speed inkjet solvent absorption against hardwood fiber swelling.
Polar Surface Energy Component
Chemical Interaction
Specific intermolecular forces arising from hydrogen bonding and dipole interactions govern the affinity of a solid surface for polar liquids. The term polar surface energy component represents the fraction of total surface energy that is due to these non-dispersive, chemical attractions. This property directly affects the adhesion of water-based inks and adhesives to treated paperboards.
Surface Measurement
Determination of this chemical component is accomplished by measuring the contact angles of polar and dispersive test liquids and applying the Owens-Wendt model. In polar surface energy component assessments, the contact angle of a highly polar liquid like water is compared with that of a purely dispersive liquid to isolate the different energy contributions. A higher polar component indicates a greater concentration of oxygen-containing functional groups, which are often introduced via corona discharge or chemical primers.
This analysis is necessary for verifying the effectiveness of surface treatments on polymer-coated packaging materials.
Print Adhesion
Packaging converters monitor this surface property to ensure that inks do not flake or rub off during shipping and handling. When the polar surface energy component is too low, water-based coatings cannot wet the substrate properly, resulting in poor adhesion and uneven ink lay. Optimizing this chemical interaction ensures strong bond strength for glues and inks alike.