摘要 |
A catalyst composition for olefin polymerization and copolymerization which contains a transition metal complex with a bidentate or a tridentate ligand and a cocatalyst mixture containing dialkylaluminum halide and dialkylmagnesium. The transition metal complexes with bidentate ligands L have the empirical formula LMX2, LMXY or L2M where M is Ti, V, Zr or Hf; X is an alkoxy group, an aryloxy group, or a halogen atom; Y is a mono- or double-bonded ligand different from X. The bidentate L ligands are described by general formulas Z-R-Z OR Z-R-W-R-Z where R is an alkylene group, a cycloalkylene group, an arylene group (unsubstituted or alkyl-substituted) or an alkylarylene group; W is CH2, O, S, N-R', or SiR'2 where R' is an alkyl or an aryl group; and Z is an oxygen atom, a sulfur atom, an N-H group or a C(=O)-O group. The transition metal complexes with tridentate ligands L' have the empirical formula L'MX where M is Ti, V, Zr or Hf; X is an alkoxy group, an aryloxy group, or a halogen atom. The tridentate L' ligands are described by general formulas <IMAGE> where R is an alkylene group or an arylene group; and Z and U are different and are an oxygen atom, a sulfur atom, an N-H group or a C(=O)-O- group. |