Greaseproof and Barrier Stocks for Fills That Defeat Plain Kraft
High-density refining and fluorine-free dispersion coatings block lipid migration and moisture breakdown where unrefined kraft papers fail under aggressive fills.
Bio-Wax Emulsion
Barrier Formation Mechanism
The suspended particles coalesce into a continuous hydrophobic film as thermal energy evaporates the carrier medium during the drying phase of production. Temperature profiles inside the drying tunnel dictate the quality of film coalescence, and inadequate thermal input leaves microscopic pinholes that compromise water vapor transmission rates. Substrate porosity influences penetration depth, so highly absorbent folding boxboard demands heavier application volumes to achieve equivalent protection compared to dense kraft paper grades.
Mechanical calendering subsequent to drying smoothes the deposited wax layer, increasing surface contact angles and enhancing water droplet repellency for frozen food packaging.
Coating Performance Limits
Converting performance depends heavily on the friction coefficient established by the lipid fraction on the outer substrate surface. Excess wax deposition reduces inter-sheet slip below acceptable packaging line tolerances, causing jams during automatic blank feeding operations. Conversely, insufficient coat weight fails to resist liquid moisture migration across creped score lines during carton erection.
Hot melt adhesive bonding strength diminishes when the wax concentration at the gluing flap exceeds specific mill limits, requiring corona treatment or targeted application patterns to expose bare fibre for proper glue penetration.
Environmental Compliance
Regulatory frameworks governing direct food contact materials dictate the purity grades permitted in the formulation of these aqueous dispersions. Analytical testing verifies that volatile organic compound emissions remain below detectable limits during high-temperature drying stages at the converting plant. Biodegradability claims apply strictly to the dispersed organic wax fraction rather than the entire coated composite structure, distinguishing renewable component origins from overall package end-of-life recyclability.
Repulping mills evaluate the detachability of the wax layer during standard alkaline deinking procedures to confirm that repulped secondary fibre yields acceptable sheet cleanliness for commercial paper production.