Two-ply web and packaging and methods for producing same

A packaging material assembly comprising:

• a first ply and a second ply arranged in an unbonded, stacked configuration;
• each of the first ply and the second ply extending across a packaging region and being free from a bonding layer over at least a majority of the packaging region;
• the first ply comprising a first paper substrate having a first surface and second surface opposite the first surface and a first heat sealable polymer layer disposed on the second surface;
• the second ply comprising a second paper substrate having a third surface and fourth surface opposite the third surface, the second paper substrate having a primer coating disposed on the third surface and a second heat sealable polymer layer disposed on the fourth surface, the primer layer comprising a polyalkyleneimine;
• wherein the first and second plies are configured to be formed into a packaging container by being joined at one or more heat seal regions, such that the first and second plies remain substantially unbonded except at the one or more heat seal regions.