Technological watch

Described herein is a water vapor barrier coating composition that is especially useful for paper-based packaging applications. The composition includes a basecoat layer and a topcoat layer that are applied to fibrous substrates in sequential order as aqueous coatings. The basecoat layer is applied and dried and then the topcoat layer is applied and dried. The basecoat layer includes an aqueous solution of ethylenically modified polyvinyl alcohol and optionally a plasticizer. The topcoat layer includes an aqueous polymeric dispersion or emulsion, compatibilized with the base layer by adding a small percentage of ethylenically modified polyvinyl alcohol solution, and optionally a viscosity modifier, defoamer, release agent, slip agent, crosslinker, and/or anti-blocking additive. The composition includes a synergistic interaction between the basecoat and the topcoat. The composition is optionally biodegradable and/or compostable, along with a coated paper stock, without the need to separate and reprocess the coating.