Coating Coverage
Structural integrity in a polymer or aqueous coating applied to paperboard ensures that the substrate remains protected from grease or gas migration. High barrier continuity prevents localized failure across the treated surface by maintaining an uninterrupted protective film. This physical attribute determines the shelf life of packaged dry foods and liquid products by stopping the movement of moisture.
Defect Detection
Measuring the presence of microscopic voids or cracks in the surface film involves electrical resistance testing or dye penetration methods. If the barrier continuity is compromised during the creasing or folding process, the substrate becomes susceptible to localized absorption. This vulnerability leading to oil staining often becomes apparent only after the packaging has been filled and stacked.
Performance Constraint
Converting operations depend on the elasticity of the polymer to maintain protection at the score lines. High-speed folding lines can induce microcracks if the dry coating lacks sufficient elongation to stretch around the outside of a fold. When this occurs, the loss of barrier continuity allows liquids to penetrate the paperboard, which reduces the strength of the container.
To prevent this, converters adjust the moisture content of the paperboard or modify the folding speed, since high acceleration forces aggravate structural failures.
