Polyethylene mixtures and films obtained therefrom.

摘要

A polyethylene mixture has a density of from 0.900 to 0.930 g/cm<3> and a melt flow rate of from 0.1 to 100 g/10 min., and comprises by weight (I) 60 to 99 parts of a random copolymer comprising ethylene and 2-10 mol% of a C3-10 alpha -olefin and having a density of 0.895 to 0.915 g/cm<3>, the programmed-temperature thermogram of said copolymer (determined with a differential scanning calorimeter after being completely melted and then gradually cooled) showing an endothermic peak in a range of 75 DEG to 100 DEG C, preferably 80-95 DEG C, with the ratio of an endotherm at said peak to the total endotherm being at least 0.8, and (II) 1 to 40 parts of a high-density polyethylene having a density of at least 0.945 g/cm<3>, the programmed-temperature thermogram of the high-density polyethylene (determined as aforesaid) showing an endothermic peak at 125 DEG C or higher, preferably 130 DEG C or higher, the sum of components (I) and (II) amounting to 100 parts. Films are formed from the mixture or composite films including such a film, and these are useful for packaging. Preparation of copolymer (I) by use of a V catalyst system is described.