A large number of barrier solutions have been developed for the packaging industry to limit solubility and diffusion of liquids through paper and paperboard packaging materials. Common options include extruding polyethylene (PE) films onto paper substrates and applying coatings containing hydrophobic waxes or platy fillers that reduce solubility and increase diffusion path lengths of the liquid permeate. However, when using such extrusion and/or coating systems, the potential to recycle the coated stock is reduced. In order to increase recyclability or repulpability of paper and paperboard used in liquid barrier applications, alternative systems are desired. In this presentation, an waterborne polymer that may be used to formulate liquid barrier coatings with flexibility, block resistance and heat seal properties is described. The coating's thermomechanical performance will be related to polymer hardness and viscoelasticity, and barrier properties correlated with calculated permeate solubility using Hansen solubility parameters.
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