POLYOLEFIN MASTERBATCH AND COMPOSITION SUITABLE FOR INJECTION MOLDING

摘要

A masterbatch composition, a polyolefin composition prepared from the masterbatch composition and articles prepared from the polyolefin composition. The masterbatch composition contains (percent by weight) from 20 % to 90 % of A) a crystalline polypropylene component containing from 25 % to 75 % of a fraction A having a melt flow rate MFR of from 0.5 to 10 g/10 min., and from 75 % to 25 % of a fraction A having a melt flow rate MFR such that a ratio MFR/MFR is from 30 to 2000; and where fractions A and A are independently selected from the group consisting of a propylene homopolymer, a random copolymer of propylene containing up to 8 % of ethylene, and a random copolymer of propylene containing up to 8 % of at least one C4-C10 alpha -olefin; and from 10 % to 80 % of B) a copolymer component of ethylene and at least one C3-C10 alpha -olefin, the copolymer containing from 10 to 70 % of ethylene, and optionally minor amounts of a diene, the copolymer being soluble in xylene at room temperature, and having an intrinsic viscosity [ eta ] of from 4 to 9 dl/g. Articles prepared by injection molding the polyolefin composition exhibit a good balance of physical properties and reduced surface defects such as tiger striping.