Tree resistant compositions.

摘要

A water tree resistant composition comprising: (a) a copolymer of at least the two comonomers, ethylene and 4-methyl-1-pentene, said copolymer having a density no greater than about 0.920 gram per cubic centimeter; or (b) a copolymer of at least the two comonomers, ethylene and 1-octene, said copolymer having a density no greater than about 0.920 gram per cubic centimeter; or (c) the copolymer of (a) or (b) grafted with a hydrolyzable vinyl silane, the copolymers of (a) and (b) being produced by contacting the relevant comonomers, under polymerization conditions, with (i) a catalyst system containing a catalyst precursor comprising magnesium, titanium, a halogen, and an electron donor, and a hydrocarbyl aluminum cocatalyst or (ii) a catalyst system containing a catalyst precursor comprising vanadium an electron donor, and a hydrocarbyl aluminum halide; a hydrocarbyl aluminum cocatalyst; and a halogen substituted lower alkane promoter.