Liquid Interaction
Fluid interaction with a substrate involves a measurable drop in energy as the liquid spreads across the surface over several seconds. Analyzing surface tension decay helps packaging engineers predict the bond strength of cold glues on recycled linerboard. This value indicates how quickly the surface energy of a treated sheet will normalize after being exposed to a corona discharge or chemical primer.
Bonding Efficiency
Initial high energy levels facilitate the wetting of the surface and the rate of change determines the final quality of the adhesion. When surface tension decay is too rapid, the ink or glue may fail to penetrate the fiber matrix effectively. This leads to issues like flaking or delamination during the finishing stages of the box-making process.
Coating Stability
Maintaining a stable surface energy is critical for substrates that will be stored for long periods before being printed. If the surface tension decay occurs unevenly, the resulting print quality will be blotchy and inconsistent. Operators use test pens or contact angle meters to verify that the board is still within the acceptable range for the planned ink system.
This verification step prevents the loss of expensive materials and reduces the need for re-treating the surface.
