Ene-type tensionless winkler foundation multilayer film

摘要

The present invention provides a polyolefin-based unstretched multilayer film, which has excellent optical characteristics, blocking resistance, heat sealing properties, hermetic sealing properties, package openability by tearing and easy peeling properties. This polyolefin-based unstretched multilayer film comprises a laminate layer, at least one intermediate layer, and a heat sealing layer. At least one intermediate layer is formed of a polyolefin-based resin containing a long-chain branched LLDPE. The long-chain branched LLDPE in the polyolefin-based resin of the intermediate layer has a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) in terms of polystyrene as determined by gel permeation chromatography, namely Mw/Mn of 7.5-15.0 and an amorphous content of 1-4% by weight as determined by a temperature raising elution fractionation method. The long-chain branched LLDPE in the polyolefin-based resin of the intermediate layer has 1.5-5.0 branches, each of which has 8 or more carbon atoms, per 1,000 carbon atoms as determined by 13C-NMR.