Substantially biodegradable and compostable high-barrier packaging material and methods for production

A bio-degradable packaging material having a water vapor transmission rate of less than 0.3 grams per 100 square inches per day at tropical conditions comprising:

• a paper substrate having a print side and a back side, wherein said substrate comprises a combination of separately refined softwood and hardwood pulps, said substrate having a permeability of less than about 0.25 nm2 and a total porosity of less than about 30%, the print side having a machine glaze;
• a coating layer on said print side of said substrate, the coating comprising one or more pigments and at least one binder, wherein at least 25% by dry weight of said one or more pigments are nano pigments of clay, talc or a mixture thereof having a particle size no greater than 90 nanometers and an aspect ratio of 90:1 or greater, and wherein the at least one binder is a protein and polyvinyl alcohol;
• a latex and polyvinyl alcohol;
• ethylene acrylic acid and polyvinyl alcohol;
• or ethylene acrylic acid and a latex;
• a metalized film layer laminated to the back side of said substrate, wherein said metalized film layer is a metalized polylactic acid film or a metalized cellophane film;
• a bonding layer between said substrate and said metalized film layer wherein said bonding layer is an adhesive, a polylactic acid resin layer, an extruded tie layer, or combinations thereof;
• and
• a polylactic acid heat seal layer over said metalized film layer.