Polypropylene laminate film

A polypropylene laminate film comprising a crystalline polypropylene layer having laminated on at least one surface thereof a copolymer which is a random copolymer of propylene, ethylene, and an alpha -olefin having at least 4 carbon atoms, the copolymer being obtained by a vapor-phase polymerization using a catalyst system comprising a solid catalyst component containing magnesium, titanium, and a halogen, an organoaluminum compound, and an electron donative compound in substantially the absence of a liquid medium, and satisfying the following requirements (1) to (7): (1) the ethylene content of the copolymer is from 3.0 to 7.0% by weight, (2) the content of the alpha -olefin having at least 4 carbon atoms of the copolymer is from 2.0 to 6.0% by weight, (3) the ratio of the ethylene content to the content of the alpha -olefin having at least 4 carbon atoms in the copolymer is at least 1.0, (4) the melt flow rate of the copolymer is 10 g/10 minutes or less, (5) the ratio of the weight average molecular weight to the number average molecular weight of the copolymer is 4.5 or less, (6) the melting point of the copolymer is 135 DEG C. or less, and (7) the amount of the n-hexane-soluble components in the copolymer is less than 5.5% by weight.