COMPOSITION BASED ON LINEAR LOW-DENSITY POLYETHYLENE HAVING IMPROVED OPTICAL PROPERTY

摘要

A polymer compsn. consists essentially of a blend of: (A) 99.5-95 wt.% of a polyolefin compsn. produced by sequential polymerisation in at least two stages, consisting essentially of: (i) 95-75 wt.% of a LLDPE contg. up to 20 wt.% of a 4-8C alpha-olefin and having a density of 0.88-0.945 g/cm3 and a melt index of 0.1-10 g/min.; and (ii) 5-25 wt.% of a copolymer of propylene with ethylene or a 4-8C alpha-olefin contg. 60-95% propylene, or a copolymer of propylene with ethylene and a 4-8C alpha-olefin contg. 80-96% propylene, 2-10% ethylene and 2-10% 4-8C alpha-olefin, the copolymer having greater than 70% xylene insoluble content, wherein the polyolefin compsn. has a melt index of 0.1-5.0 g/10 mins.; and (B) 0.5-5 wt.% of a low density polyethylene having a density of 0.916-0.925 g/cm3 and a melt index of 0.2-20 g/10 mins. Also claimed are: a blown film of a polymer compsn. as above; a cast film of the polymer compsn. above; an extrusion coating of the polymer compsn. above. Pref. (A) (i) is a LLDPE with a C4 alpha-olefin. The alpha-olefin in (A) (ii) is a 1-butene. (A) (ii) is a terpolymer of 88-96% of propylene, 2-8% ethylene and 2-7% 4-8C alpha-olefin. (A) is present in an amt. of 99-95 wt.% and (B) is present in an amt. of 1-5 wt.%. (A) (ii) is prepd. in the first stage.