Polymer Chemistry
Waterborne synthetic resin formulations applied to paperboard substrates provide fluid resistance without inhibiting repulping operations. An acrylic dispersion coating consists of microscopic acrylate polymer particles suspended in water, forming a continuous protective film as the liquid phase evaporates during hot air drying. The resin polymerizes to create grease resistance and water repellency on paper surfaces while maintaining thermal stability during heat sealing.
Substrate coverage requires uniform particle coalescence to eliminate micro-voids through which fats or liquid moisture penetrate.
Substrate Deposition
Metering rod stations apply liquid dispersion onto moving paper webs at controlled coat weights between three and eight grams per square metre. Evaporation of the aqueous carrier forces suspended polymer spheres into contact, triggering deformation and interdiffusion of molecular chains across particle boundaries. Temperature management within drying tunnels dictates film integrity, as temperatures below the minimum film-forming threshold yield brittle, porous surfaces prone to cracking.
Barrier Boundary
Substrates treated with this water-based polymer system remain recyclable in standard hydrapulping systems because alkaline repulping breaks the film into fragments that separate during flotation. High relative humidity environments weaken moisture vapour resistance when exposure exceeds forty-eight hours. Extended storage under heavy stack pressures induces block resistance failure if glass transition temperatures fall below ambient warehouse conditions.
