Corona Decay Kinetics and Solventless Adhesive Wetting in Polypropylene Lamination
Corona decay on polypropylene impairs solventless adhesive wetting, requiring in-line treatment to maintain dynamic surface energy above 40 dyn/cm.
ASTM D2578 Dyne Solutions
Wetting Measurement
Chemical mixtures of ethyl cellosolve and formamide calibrated to specific surface tension levels provide a method for determining the wettability of polyolefin films. These astm d2578 dyne solutions are applied to a substrate using a cotton swab to observe the behavior of the liquid film over a two second interval. If the liquid does not bead up within this timeframe, the surface energy of the film is considered equal to or greater than the rating of the liquid.
Solution Chemistry
Standardized proportions of the two base chemicals create a range of values typically spanning from 30 to 56 dynes per centimetre. Producers rely on astm d2578 dyne solutions to verify that corona treatment has sufficiently modified the nonpolar surface of materials like polyethylene or polypropylene. This modification allows inks and adhesives to anchor properly.
A mismatch between the liquid and the surface results in poor transfer. The specific ratios are defined in the standard to ensure repeatability across different testing laboratories. Proper handling prevents evaporation which would otherwise skew the concentration and lead to false readings.
Application Boundary
Accuracy depends on the freshness of the reagents and the absence of contaminants on the test surface. Since the formamide in astm d2578 dyne solutions is hygroscopic, the fluid properties change if the bottles remain open in humid environments. The test identifies the wetting tension rather than the total surface energy.