Polypropylen-Zusammensetzungen und daraus gefertigte Filme

A crystalline propylene polymer (100 parts by wt) which can be a random copolymer with an olefin, having a molecular weight distribution (Mw/Mn) of less than 5.0 and preferably a melt flow rate of 3.0 to 50 g/10 minutes, is compounded with 0.001 to 1.0 part of a crystal nucleating agent which can be inorganic, organic or polymeric (e.g. talc, an aromatic carboxylic acid metal salt or a vinyl cycloalkane polymer), preferably of mean particle size 6.0 mu m or less, such that the crystallization temperature of the composition is at least 1.5 DEG C, preferably 2.0 DEG C, higher than that of the propylene polymer. Synthesis of the polymer is described with a Ziegler-Natta catalyst. The composition is used for melt-extrusion of a film of thickness 10 to 500 mu m by a T-die film-forming method in which the surface temperature of the cooling roll is at least 50 DEG C. Multilayer films can be co-extruded. The films have good transparency, which has low dependency on the film thickness, and are useful for packaging.