Patent ID: 8043712

Claim:
A heat-sealable multilayer polypropylene-based resin film, which is an oriented polypropylene-based resin film made of a laminate of 3 or more layers comprising: (i) a substrate layer having a melting point of 155° C. or less and comprising a crystalline polypropylene-based resin and 20-50 wt % of a propylene-α-olefin copolymer; (ii) an intermediate layer comprising 65-95 wt % of a propylene-α-olefin copolymer having a cold xylene-soluble content of 3 wt % or less; and (iii) a thermal adhesion layer having a melting point of 150° C. or less; wherein the substrate layer has a melting point higher than a melting point of the intermediate layer, wherein the intermediate layer as a whole has a cold xylene-soluble content of 2.2 wt % or less and the intermediate layer has a thickness of 4 μm or above, and wherein the thickness of the substrate layer is 30-89% of the total layer thickness, and the thickness of the thermal adhesion layer is 0.8-6 μm and 1-20% of the total layer thickness.