Dispersion Barrier Performance in Folding Boxboard Substrates
Aqueous dispersion barrier performance depends on wet coat weight uniformity, film drying coalescence, and creasing matrix geometry that prevents score line cracking.
Fiber Wicking Resistance
Liquid Repulsion
Material properties determine the ability of a paper or board substrate to prevent the lateral absorption of liquids along the internal fiber network. High fiber wicking resistance is essential for packaging that comes into contact with condensation, oils, acids, or fatty chemicals. This characteristic prevents the edges of a carton from softening or discoloring when exposed to moisture.
Fiber wicking resistance is a critical metric for refrigerated or frozen food containers.
Chemical Sizing
Internal sizing agents added during the wet end of the papermaking process modify the surface energy of the cellulose fibers to inhibit capillary action. When fiber wicking resistance is high, the liquid remains on the surface or is repelled at the cut edge of the board. This resistance is measured by timing how long a colored dye takes to travel a set distance through the material.
Adjusting the ratio of alkyl succinic anhydride or rosin size controls this performance.
Quality Threshold
Degradation of this property occurs if the board is subjected to high temperatures or mechanical stress that breaks the sizing bond. If the fiber wicking resistance fails, the structural integrity of the package will collapse under its own weight. Testing usually involves the Cobb method or an edge wick test.