Spatial Distribution
Structural mapping of liquid applications on paperboard substrates reveals the local variations in dry barrier thickness across the fiber matrix. Analysis of coat weight topography indicates how evenly a polymer or aqueous formulation lies across the microscopic peaks and valleys of the base sheet. Liquid barriers often pool in surface depressions, leaving the elevated fibers with a thin layer that remains vulnerable to moisture or grease penetration.
When the sheet passes through the drying section of a coating line, uneven distribution can cause differential shrinkage, which creates localized stresses that trigger curl.
Surface Analysis
Measuring the profile requires non-destructive optical or spectroscopic methods that map the chemical signatures of the surface. Infrared imaging scans the treated paper to detect the localized density of the coating material. These readings are converted into a three-dimensional map that identifies thin spots where barrier failure is likely to occur.
Barrier Performance
Protection levels depend on maintaining a minimum barrier thickness across the entire sheet. Uneven coat weight topography leads to premature failure in packaging intended for moisture-sensitive products. When the protective film is too thin on fiber peaks, gases can migrate through the packaging board, which shortens the shelf life of the contents.
