Preparation of low-density ethylene copolymers in fluid bed reactor

Claim 1

A continuous catalytic process for producing ethylene copolymer containing ≧90 mol percent of ethylene and ≦10 mol percent of one or more C 3 to C 8 α olefins with a Ti containing catalyst at a productivity of ≧500,000 pounds of polymer per pound of Ti under a pressure of <1000 psi in a gas phase fluid bed reaction, said polymer being produced in granular form and having a density of about 0.91 to 0.94 and a melt flow ratio of ≧26 to ≦40, which comprises copolymerizing ethylene with one or more C 3 to C 8 α olefin monomers at a temperature of about 30° to 105° C. by contacting a monomer charge containing said C 3 to C 8 α olefin monomers and ethylene in a mol ratio no greater than 0.6, in a gas phase reaction zone, with particles of a catalyst system comprising an activated copulverized composition, wherein said composition has the following empirical composition Mg.sub.m Ti(OR).sub.n X.sub.p [ED].sub.q wherein m is ≧5 to ≦200 n is 0 or 1 p is ≧10 to ≦400 q is >0 to 3.0 R is a C 1 to C 14 aliphatic or aromatic hydrocarbon radical, or COR' wherein R' is a C 1 to C 14 aliphatic or hydrocarbon radical, X is Cl, Br, I or mixtures thereof, and ED is a liquid organic electron donor compound selected from the group consisting of alkyl esters of aliphatic and aromatic carboxylic acids, aliphatic ethers, cyclic ethers, aliphatic ketones and di- or polyamino compounds, said composition prepared by copulverizing magnesium dihalide with a complex obtained by contacting a titanium compound of the formula Ti(OR).sub.a X.sub.b wherein R and X are as previously defined and a is 0 or 1, b is 2 to 4 inclusive and a+b=3 or 4, with an electron donor compound ED, as previously defined, said copulverized composition being either partially activated with >0 to ≦10 mols of activator compound per mol of titanium compound in said copulverized composition prior to feeding of the activated copulverized composition to said reaction zone and then being completely activated in said reaction zone with ≧10 to 400 mols of activator compound per mol of titanium compound in said copulverized composition, or completely activated in said reaction zone with ≧10 to 400 mols of activator compound per mol of titanium compound in said copulverized composition, said activator compound having the formula Al(R").sub.c X".sub.d H.sub.e wherein X' is Cl or OR'", R" and R'" are the same or different and are C 1 to C 14 saturated hydrocarbon radicals, d is 0 to 1.5 e is 0 or 1 c+d+e=3.