Paper-based multilayer packaging materials and methods

A method of making a multilayer packaging material, the method comprising:

• providing a substrate formed of a cellulosic fiber-based material, the substrate having a first major surface and a second major surface opposite the first major surface;
• attaching an oxygen barrier layer formed of a PVOH material to the first major surface of the substrate, wherein the oxygen barrier layer defines a product-contacting surface of the multilayer packaging material, and further wherein the oxygen barrier layer is heat sealable;
• and
• attaching at least one moisture barrier layer to the substrate, the moisture barrier layer selected from the group consisting of:
• (a) an inner moisture barrier layer disposed intermediate the substrate and the oxygen barrier layer;
• and
• (b) an outer moisture barrier layer disposed on the second major surface of the substrate.

A method of packaging a product, comprising:

• placing a multilayer packaging material around and in contact with the product, said multilayer packaging material comprising:
• a substrate formed of a cellulosic fiber-based material, the substrate having a first major surface and a second major surface opposite the first major surface;
• an oxygen barrier layer formed of a PVOH material attached to the first major surface of the substrate, wherein the oxygen barrier layer is an innermost layer of the multilayer packaging material and further wherein the oxygen barrier layer is heat sealable;
• and
• at least one moisture barrier layer attached to the substrate, the moisture barrier layer selected from the group consisting of:
• (a) an inner moisture barrier layer attached to the first major surface of the substrate and disposed intermediate the substrate and the oxygen barrier layer;
• and
• (b) an outer moisture barrier layer attached to the second major surface of the substrate;
• and
• bringing a first portion of the oxygen barrier layer into opposing and contacting relation with a second portion of the oxygen barrier layer and heat sealing the first portion of the oxygen barrier layer to the second portion of the oxygen barrier layer to hermetically seal the product within the multilayer packaging material.