ETHYLENE/PROPYLENE/ETHYLIDENE NORBORNENE RUBBERS

摘要

A process for the production of an EPDM wherein about 20 to about 50 percent by weight of the terpolymer chains contain less than about 15 percent by weight of the total moieties based on ethylidene norbornene comprising reacting ethylene, propylene, ethylidene norbornene, and hydrogen, in the gas phase, in a fluidized bed, under polymerization conditions, in the presence of a catalyst system comprising: (a) the reaction product of a vanadium compound and an electron donor, which is an organic Lewis base in which the vanadium compound is soluble; (b) at least one modifier having the formula BX3 or AlR(3-a)Xa wherein each R is independently alkyl or aryl having 1 to 14 carbon atoms; each X is independently chlorine, bromine, or iodine; and a is 0, 1, or 2, wherein components (a) and (b) are impregnated into an inorganic support; (c) a halocarbon promoter; and (d) a hydrocarbyl aluminum cocatalyst with the following provisos; (i) the partial pressure of ethylene is in the range of about 80 to about 150 psi; (ii) the molar ratio of propylene to ethylene is in the range of about 0.35:1 to about 0.8:1; (iii) the molar ratio of hydrogen to ethylene is in the range of about 0.0005:1 to about 0.008:1; and (iv) the amount of ethylidene norbornene is about 2 to about 10 percent by weight based on the weight of the fluidized bed.