| abstract |
A process for the production of an ethylene homopolymer or copolymer comprising passing ethylene with or without at least one alpha-olefin comonomer having 3 or more carbon atoms into contact with a mixed catalyst system, under polymerization conditions, said mixed catalyst system comprising: n (a) the reaction product of (i) a vanadium halide having the formula VX 3 wherein X is chlorine, bromine, or iodine and each X is alike or different; (ii) a modifier having the formula BX 3 or AlR.sub.(3-a) X a and (iii) an electron donor n (b) one of the following: n (i) a complex having the formula ZrMg b X c (ED) d ; or n (ii) a vanadium oxy compound having the formula VOX 3 , VOX 2 , VOX, or VO 2 X wherein X is as defined above, or VO(OR) 3 n (c) a hydrocarbyl aluminum cocatalyst; and n (d) a halocarbon promoter having the formula R e CX.sub.(4-e) wherein R is hydrogen or an unsubstituted or halo substituted alkyl radical having 1 to 6 carbon atoms; each R is alike or different; X is chlorine, bromine, iodine, or fluorine; each X is alike or different and e is 0, 1, or 2 provided that, if no fluorine is present, e is 2. |