ETHYLENE/PROPYLENE COPOLYMER RUBBERS

摘要

A process comprising contacting a mixture comprising ethylene, propylene, and, optionally, a diene, in the gas phase, under polymerization conditions, with a catalyst system comprising: (a) a catalyst precursor, in independent or prepolymer form, consisting of vanadium (acetylacetonate)3; (b) optionally, a support for said precursor; (c) a cocatalyst consisting essentially of (i) an alkylaluminum halide having the formula AlR(3-a)Xa wherein each R is independently alkyl having 1 to 14 carbon atoms; each X is independently chlorine, bromine, or iodine; and a is 1 or 2, and (ii) optionally, a trialkylaluminum provided that the molar ratio of alkylaluminum halide to trialkylaluminum is at least about 1.5:1; and (d) optionally, a promoter, which is a chlorinated ester having at least 2 chlorine atoms; a saturated or unsaturated aliphatic halocarbon having at least 3 carbon atoms and at least 6 halogen atoms; or a haloalkyl substituted aromatic hydrocarbon wherein the haloalkyl substituent has at least 3 halogen atoms.