Patent ID: 8043674

Claim:
A sealable composite flexible packaging structure comprising: (a) a first substrate, wherein the first substrate comprises paper, cloth, polymeric materials, cardstock or coated paper; and (b) a second substrate comprising a multi-layer film including at least: (1) a core layer comprising from 60 wt % to 95 wt % of a core polymer and from 5 wt % to 40 wt % of a first polymer, wherein the core polymer comprises a first isotactic polypropylene; (2) a sealant layer, wherein said sealant layer comprises co- or terpolymers of ethylene, propylene, and butylenes; and (3) a first tie layer intermediate the core layer and the sealant layer, the first tie layer is on a side of the core layer opposite the first substrate, the first tie layer comprising the first polymer and a second isotactic polypropylene having a molecular weight distribution greater than the molecular weight distribution of the first isotactic polypropylene; wherein the first substrate is adhered to the second substrate on a side of the second substrate opposite the tie layer, the first substrate is adhered to the second substrate by at least one of lamination, coating, and coextrusion; wherein the DSC melting point temperature of the core layer is greater than the DSC melting point temperature of the tie layer; and wherein the sealable composite flexible packaging structure does not contain an inner layer of foil.