Aqueous Barrier
Aqueous polymer emulsions applied to paperboard surfaces form functional barrier coatings or protective decorative varnishes upon water evaporation. Composed of acrylic, styrene-butadiene, or vinyl acetate synthetic polymers suspended in water, waterborne dispersion coating replaces traditional extruded polyethylene films on paper plates, cups, and folding cartons. The coating governs grease resistance, liquid water holdout, and scuff protection while allowing repulpability in standard mill systems.
Solvent-based lacquers containing volatile organic solvents and 100-percent solid UV-curable coatings belong to distinct resin categories.
Film Formation
Infrared dryers and hot air knives evaporate the water carrier, forcing suspended polymer particles to coalesce into a continuous protective film layer on the paper surface. Applying waterborne dispersion coating demands precise coat weight control to achieve pinhole-free barrier performance without causing paper sheet curling or heat-seal blocking during reel storage. Insufficient drying leaves residual moisture that weakens paperboard compression strength and causes blocking in stacked sheets.
Formulators add mineral fillers to enhance heat-seal performance and lower coating costs.
Recyclability Limit
Heavy dispersion coat weights exceeding fifteen grams per square metre impair repulping efficiency by forming oversized insoluble flakes during pulping. High alcohol content in packaged liquids can soften acrylic dispersion films, compromising barrier integrity.
