Cocatalyst for vanadium/titanium containing polymerization catalyst

摘要

The present invention relates to a novel catalyst component for ethylene polymerization comprising vanadium and titanium. Moreover, when the vanadium/titanium containing catalyst of the present invention is employed with an aluminum-containing cocatalyst enhanced activity as well as melt index is obtained.PPThe present invention is directed to a novel halosilane cocatalyst component which, when used in conjunction with an aluminum containing cocatalyst, is effective in increasing the activity of a silica supported titanium/vanadium containing solid catalyst component in the polymerization of ethylene and/or &agr;-olefins. In addition to the increased catalytic activity, the polymers produced by the present invention exhibit improved melt index values compared with melt index values typically obtained using prior art catalyst systems. Thus, the catalyst system of the instant invention represent an advancement in the art in view of the combination of increased activity, i.e., yield of polymer produced, and physical properties of the polyolefin product.PPIn another aspect of the present invention, a process for polymerizing ethylene and/or . alpha.-olefins is disclosed. In this process at least one olefin is polymerized under olefin polymerization conditions utilizing the catalyst system of the present invention, which includes the solid catalyst component of the present invention, along with the first cocatalyst, an aluminum-containing compound, and the second cocatalyst, a halosilane.