Waterborne primer and oxygen barrier coating with improved adhesion

An oxygen and moisture resistant barrier film structure for packaging comprising:

• a) at least one substrate;
• b) a primer layer formed by coating at least one surface of the substrate with a primer composition comprising:
• i) at least one aqueous polyurethane dispersion (A);
• and
• ii) at least one water dispersible crosslinking agent (B) selected from the group consisting of polyfunctional isocyanate and polyfunctional aziridine;
• c) an oxygen and moisture resistant barrier formed by coating onto said primed treated surface of the substrate, a barrier coating composition comprising:
• i) at least one aqueous polyvinyl alcohol or its copolymers (C);
• and
• ii) at least one crosslinking agent (D) selected from the group consisting of polyethyleneimine, melamine, melamine derivatives and mixtures thereof.

A heat sealable multi-layer structure comprising:

• a) a substrate having a first surface and a second surface;
• the second surface being opposite the first surface;
• b) a primer layer comprising at least one aqueous polyurethane dispersion (A) and at least one water dispersible crosslinking agent (B) applied directly on the first surface of the substrate;
• c) a barrier layer comprising at least one aqueous polvinyl alcohol or its copolymers (C) and at least one crosslinking agent (D) applied directly onto the primer layer;
• and
• d) a heat seal layer applied directly onto the first primer layer, wherein the first primer layer adheres together with the barrier layer and the seal layer.