Heat-sealable plastic film, process for its manufacture, and the use of the film

Opaque film of thermoplastic organic material which has been oriented by biaxial stretching, comprising a base layer of a polymer or copolymer of an .alpha.-olefin having 2 to 6 carbon atoms containing an amount between about 1 and 25 percent by weight, calculated on the weight of the polymer, of finely distributed solid particles ranging in size from about 0.2 to 20 .mu.m sufficient to render said film opaque, and carried on at least one surface of said base layer, a heat-sealable layer comprising a copolymer comprised predominatly of propylene, selected from a copolymer of propylene with ethylene, a copolymer of propylene with butene, or a terpolymer of propylene with ethylene and a further .alpha.-olefin having from 4 to 10 carbon atoms, whereby said film is opaque and has improved pearlescent lustre.