Catalyst composition for copolymerizing ethylene

Claim 1

A continuous process for producing ethylene copolymers containing at least 90 mol percent of ethylene and no more than 10 mol percent of one or more alpha olefins containing from 3 to 8 carbon atoms, said copolymers being produced in granular form and having a density of from 0.91 g/cm 3 to 0.94 g/cm 3 , which comprises contacting a mixture of ethylene and at least one alpha olefin containing from 3 to 8 carbon atoms, at a temperature of from 30° C. to 105° C. and a pressure no greater than 1000 psi, in a gas phase reaction zone, with particles of a catalyst system comprising a precursor composition having the formula: Mg.sub.m Ti(OR).sub.n X.sub.p [ED].sub.q wherein R is an aliphatic or aromatic hydrocarbon radical containing from 1 to 14 carbon atoms, or COR' wherein R' is an aliphatic or aromatic hydrocarbon radical containing from 1 to 14 carbon atoms, X is selected from the group consisting of Cl, Br, I, and mixtures thereof, ED is an organic electron donor compound selected from the group consisting of alkyl esters of aliphatic and aromatic carboxylic acids, aliphatic ethers, cyclic ethers and aliphatic ketones, m is 0.5 to 56, n is 0, 1 or 2, p is 2 to 116, and q is 2 to 85, said precursor composition being diluted with an inert carrier material, and being completely activated in the reaction zone with a mixture of a dihydrocarbyl aluminum halide compound and a trihydrocarbyl aluminum compounded wherein the molar ratio of dihydrocarbyl aluminum halide compound to trihydrocarbyl aluminum compound is maintained at from 4:1 to 20:1, said dihydrocarbyl aluminum halide compound and said trihydrocarbyl aluminum compound being employed in an amount such as to provide a total aluminum:titanium molar ratio in said reaction zone of from 10:1 to 400:1, said dihydrocarbyl aluminum halide compound having the formula: R".sub.2 AlX wherein R" is a saturated hydrocarbon radical containing from 1 to 14 carbon atoms or OR'", wherein R'" is a saturated hydrocarbon radical containing from 1 to 14 carbon atoms, and said trihydrocarbyl aluminum compound having the formula: R'".sub.3 Al wherein R'" is a saturated hydrocarbon radical containing from 1 to 14 carbon atoms, and X is selected from the group consisting of Cl, Br, I, and mixtures thereof.