Mineral Oil Analysis in Recycled Fibre Food Packaging
Verify MOSH and MOAH compliance in recycled fibre packaging using accredited HPLC-GC-FID testing, validated functional barriers, and complete declarations of compliance.
Aqueous Dispersion Barrier
Coating Mechanics
Liquid suspension applied to packaging paper provides water resistance by forming a continuous surface film over porous cellulose fibres. An aqueous dispersion barrier relies on high shear viscosity control during blade or rod application to prevent excessive binder penetration into untruthful substrate voids. Polymer particles coalesce as thermal energy drives moisture from the wet web during drying stages, creating a closed polymeric network that blocks moisture vapour transmission.
Calendering operations subsequently compress this dried film to eliminate pinholes and smooth microscopic surface roughness, directly improving Cobb sizing test results without disrupting paper repulpability. Coaters must balance solids content and rheology to maintain uniform grammage across wide machine deckles while avoiding web breaks caused by improper drying curves.
Substrate Compatibility
Cellulose matrix porosity dictates how effectively dispersed polymers anchor to packaging boards during converting lines. Raw kraft liners require smooth pre-coatings to prevent uneven absorption of the aqueous dispersion barrier, which otherwise causes localized film thickness variations and reduced grease resistance. Starch sizing applied at the wet stack prepares the fibre network by sealing surface capillaries, ensuring the topcoated polymer layer remains entirely on the exterior plane.
Converting plants monitor contact angle measurements constantly to verify that surface tension levels remain compatible with water-based emulsion chemistry before production runs begin.
End-Use Performance
Recyclability standards demand that protective packaging coatings separate cleanly from pulp slurries during standard repulping cycles. An aqueous dispersion barrier achieves this separation because polymer particles redisperse poorly or remain large enough to be removed by mechanical screening, unlike extruded polyethylene laminates that fragment into difficult-to-filter flakes. Brand owners specify these dispersion coatings to meet stringent single-use packaging directives while maintaining barrier integrity against food oils and ambient humidity.
End-of-life processing proves that water-based formulations reduce overall carbon footprints compared to petroleum-derived plastic films bonded through thermal extrusion.