摘要 |
<p>This invention concerns a catalyst system comprising at least one homogeneous catalyst and at least one heterogeneous catalyst, specifically, a metallocene catalyst and a conventional Ziegler-Natta catalyst, respectively. This invention is useful in the polymerization of any polymer in which separate polymerizations with a homogeneous catalyst and with a heterogeneous catalyst are possible, but preferably, polymerization of olefins, more preferably, a-olefins, and, most preferably, propylene. This invention provides a catalyst system which facilitates use of a homogeneous catalyst but eliminates the disadvantages of such a system. This invention produces a polymer with molecular weight distribution (MWD) as broad or broader than the MWD of the heterogeneous catalyst alone. Hydrogen can be used to control molecular weight distribution of a polymer produced with this invention. <IMAGE></p> |