Barrier Classification
Surface energy measurements define the oleophobic performance of paper substrates through a standardized series of reagent liquids. Kit test grease resistance gauges the capillary penetration depth of mixed castor oil, toluene, and heptane solutions dropped onto a flat sample. Higher numbered values denote a surface tension that resists wetting by progressively aggressive solvent mixtures, providing a quantitative boundary for packaging materials intended to contain fatty food products.
Procedural Application
Laboratory technicians apply a precise volume of the testing solution from a height to avoid mechanical force against the substrate fibers. Observations occur exactly fifteen seconds after initial contact to determine whether the fluid spreads or beads on the surface. Operators remove the liquid and inspect the area for visible darkening or translucency changes which indicate a failed barrier performance.
Precise control of the ambient laboratory temperature remains necessary because thermal shifts alter the viscosity of the hydrocarbon fluids used during the procedure. This protocol establishes a consistent check for mills coating bleached or unbleached kraft papers with fluorochemicals or specialty bio-polymers.
Performance Expectation
Industrial converting operations rely on this numeric scale to predict the shelf stability of fast food wrappers, pet food bags, and confectionery wraps. Achieving a specific kit number indicates the board successfully maintains a physical separation between oily ingredients and the outer packaging layer to prevent unsightly staining or substrate degradation. Low readings demonstrate a porous fiber structure that requires additional mechanical barriers or higher concentration chemical treatments to ensure safe containment.
Material selection for complex supply chains depends on the correlation between these test results and the actual fat content of the intended commodity.
