AQUEOUS BARRIER COATINGS AND METHODS OF IMPROVING BARRIER PROPERTIES OF PACKAGING MATERIALS

1 . A substrate having improved barrier properties comprising:

a) a substrate having an outermost surface and an innermost surface disposed opposite one another;

b) an optional primer coating layer disposed on and in direct contact with the outermost, innermost, or both surfaces of the substrate;

c) a biodegradable coating layer comprising at least one biodegradable polymeric emulsion, disposed on and in direct contact with the outermost surface, the innermost surface, or both surfaces of the substrate or optional primer coating layer;

d) optionally, one or more polymeric coatings disposed on the surface of the biodegradable coating layer; and

e) a topcoat layer comprising one or more polymeric emulsions, and optionally one or more wax emulsions, disposed on the surface of the biodegradable coating layer or optional polymeric coating disposed on the surface of the biodegradable coating.

2 . The substrate according to claim 1 , wherein the optional primer coating compromises at least one polymeric emulsion chosen from styrene butadiene, styrene acrylate, polyethylene, polypropylene, polyethylene oxide, polyacrylate, polyvinyl alcohol, polyvinyl acetate, polyvinyl amine, and combinations thereof; and an inorganic pigment slurry chosen from talc, kaolin, calcium carbonate, mica, montmorillonite, and combinations thereof.

3 . The substrate according to claim 1 , wherein the optional primer coating layer has a polymeric content of from about 30 wt. % to about 70 wt. %, and an inorganic pigment content between 30 wt. % and 70 wt. % based on the total dry weight of the primer coating.

4 . The substrate according to claim 1 , wherein the optional primer coating is applied at a dry coat weight of from about 1 g/m 2 to about 50 g/m 2 .

5 . The substrate according to claim 1 , wherein the at least one biodegradable polymeric emulsion is chosen from polyvinyl alcohol, polyethylene oxide, methylcellulose, cellulose acetate, sodium alginate, polyhydroxyalkanoates, polylactic acid, silk fibroin, soy protein, chitosan, thermoplastic starch, crosslinked starch, and combinations thereof.

6 . The biodegradable coating according to claim 1 , further comprising a plasticizer chosen from sugar alcohols, glycerol, propylene glycol, glyceryl triacetate, polymeric polyols, urea, ethanol, isopropanol, and combinations thereof.

7 . The biodegradable coating according to claim 1 , further comprising an inorganic pigment chosen from talc, kaolin, calcium carbonate, mica, montmorillonite, and combinations thereof.

8 . The substrate according to claim 1 , wherein the biodegradable coating layer has a polymeric content of from about 40 wt. % to about 100 wt. %, a pigment content of from 0 wt. % to about 50 wt. %, and a plasticizer content of from 0 wt. % to about 20 wt. % based on the total dry weight of the biodegradable coating.

9 . The substrate according to claim 1 , wherein the biodegradable coating is applied at a dry coat weight of from about 1 g/m 2 to about 50 g/m 2 .

10 . The substrate according to claim 1 , wherein the one or more polymeric emulsions of the topcoat layer is chosen from styrene butadiene, styrene acrylate, polyethylene, polypropylene, polyethylene oxide, polyacrylate, polyvinyl alcohol, polyvinyl acetate, polyvinyl amine, and combinations thereof.

11 . The substrate according to claim 1 , wherein the optional one or more wax emulsions of the topcoat layer is chosen from a paraffin, polyethylene, montan, palm, palm kernel, coconut, rapeseed, soybean, sunflower, castor, carnauba, beeswax, shellac, candelilla, sugar cane, rice bran, stearates, laurates, oleates, and combinations thereof.

12 . The substrate according to claim 1 , wherein the topcoat layer has a polymeric content of from about 50 wt. % to about 100 wt. %, and a wax content of from 0 wt. % to about 50 wt. % based on the total dry weight of the topcoat.

13 . The substrate according to claim 1 , wherein the topcoat is applied at a dry coat weight of from about 1 g/m 2 to about 50 g/m 2 .

14 . The substrate according to claim 1 , wherein the substrate is paper or fiber.

15 . A method of providing improved barrier properties of a substrate comprising:

a) providing a substrate having an outermost surface and an innermost surface disposed opposite one another;

b) optionally applying a primer coating layer disposed on and in direct contact with the outermost surface, the innermost surface, or both surfaces of the substrate;

c) applying a biodegradable coating layer comprising at least one biodegradable polymeric emulsion, disposed on and in direct contact with the outermost surface, the innermost surface, or both surfaces of the substrate or optional primer coating layer;

d) optionally applying one or more polymeric coatings disposed on the surface of the biodegradable coating layer; and

e) applying a topcoat layer comprising one or more polymeric emulsions, and optionally, one or more wax emulsions, disposed on the surface of the biodegradable coating layer or optional polymeric coating disposed on the surface of the biodegradable coating.

16 . The method according to claim 15 , wherein the optional primer coating is applied to the substrate at a dry coat weight of from about 1 g/m 2 to about 50 g/m 2 .

17 . The method according to claim 15 , wherein the biodegradable coating further comprises a plasticizer and/or an inorganic pigment.

18 . The method according to claim 15 , wherein the biodegradable coating is applied at a dry coat weight of from about 1 g/m 2 to about 50 g/m 2 .

19 . The method according to claim 15 , wherein the topcoat is applied at a dry coat weight of from about 1 g/m 2 to about 50 g/m 2 .

20 . The method according to claim 15 , wherein the substrate is paper or fiber.