Packaging material and packaging bag

A packaging material comprising:

• a first substrate;
• a water-based ink layer;
• an adhesive layer;
• and
• a second substrate in this order, wherein
• the adhesive layer is formed of a urethane-based adhesive containing a polyisocyanate and a polyol,
• the polyisocyanate contains a chain isocyanate with a symmetrical structure or an isocyanate polymer derived from the chain isocyanate, and
• the polyisocyanate partially penetrates a region near an interface between the water-based ink layer and the first substrate so as to satisfy formula (a):
• (
• N
• i
• -
• N
• ii
• )
• ≥
• 0.5
• formula
• ⁢
• (
• a
• )
• wherein in formula (a),
• Ni denotes a nitrogen content (unit:
• % by mass) in the first substrate measured in region (i) at a distance within 0.06 to 0.26 μm from the interface, and
• Nii denotes an average of nitrogen contents (unit:
• % by mass) in the first substrate measured in 1-μm-thick region (ii), 1-μm-thick region (iii), and 1-μm-thick region (iv) including positions at distances from the interface corresponding to 30%, 60%, and 80% of a thickness of the first substrate, respectively,
• the polyisocyanate contains a biuret or an isocyanurate of the chain isocyanate as the isocyanate polymer,
• the chain isocyanate is hexamethylene diisocyanate, and
• the polyester polyol is a compound containing two or more polyol hydroxyl groups and having a polyester structure as a main backbone.