| 摘要 |
<p>A catalyst which is useful in slurry or gas phase olefin polymerizations and which is prepared by depositing a combination of an organometallic complex of a group 4 metal and a so-called ionic activator on a metal oxide support. The organometallic complex is characterized by being unbridged and by having a cyclopentadienyl ligand, a phosphinimine ligand and an activatable ligand. The 'ionic activator' (for example, triphenylcarbenium tetrakis (pentafluorophenyl) boron) is co-deposited with the organometallic complex. The metal oxide support is pre-treated with, for example, an aluminum alkyl in an amount which is at least equivalent to the molar concentration of surface hydroxyls on the support. The catalyst prepared by this process is highly active for ethylene polymerization.</p> |
