Patent ID: 6902795

Claim:
A heat-sealing film which comprises a biaxially oriented polyethylene terephthalate layer as the outer-most layer, a polyethylene resin layer as the second layer, a polyolefin type resin layer as the third layer and the sealant layer as the fourth layer, wherein (a) the polyethylene resin layer is disposed between the polyethylene terephthalate layer and the polyolefin type resin layer, and (b) the polyolefin type resin layer as being disposed between the polyethylene resin layer and the sealant layer, wherein the first, second, third and fourth layers are different and wherein the sealant layer is made of a resin composition comprising from 50 to 100 wt % of the total of the following components (i) to (iv): (i) from 5 to 50 wt % of a block copolymer of from 50 to 95 wt % of a styrene-type hydrocarbon and from 5 to 50 wt % of a conjugated diene-type hydrocarbon, (ii) from 5 to 50 wt % of an ethylene/α-olefin random copolymer, (iii) from 5 to 70 wt % of a block copolymer of from 10 to 50 wt % of a styrene-type hydrocarbon and from 50 to 90 wt % of a conjugated diene-type hydrocarbon, and (iv) from 0 to 50 wt % of an impact-resistant polystyrene.