Process for polymerizing propylene by using a novel metallocene catalyst

A process for propylene polymerization comprising polymerizing propylene or copolymerizing propylene and at least one kind of .alpha.-olefin selected from the group consisting of ethylene and .alpha.-olefins of 4 to 10 carbon atoms to obtain propylene homopolymer or propylene copolymer containing propylene units in an amount of not less than 50% by mol in the presence of a propylene polymerization catalyst selected from the group consisting of

• (I) a propylene polymerization catalyst produced by contacting, in any order,
• (A) a propylene polymerization catalyst component comprising a transition metal compound represented by the following formula (I):
• ##STR21## M is a transition metal selected from the group consisting of zirconium and hafnium;
• R.sup.1 is a hydrocarbon group of 2 to 6 carbon atoms;
• R.sup.2 is an aryl group selected from the group consisting of anthracenyl and phenanthryl, which may be substituted with a hydrocarbon group of 1 to 20 carbon atoms;
• X.sup.1 and X.sup.2 are each a hydrogen atom, a halogen atom, a hydrocarbon group of 1 to 20 carbon atoms, a halogenated hydrocarbon group of 1 to 20 carbon atoms, an oxygen-containing group or a sulfur-containing group;
• and
• Y is a divalent silicon-containing group selected from the group consisting of dialkylsilylene, alkylarylsilylene and diarylsilylene;
• with
• (B) at least one compound selected from the group consisting of
• (B-1) an aluminoxane, and
• (B-2) a compound which reacts with said transition metal compound to form an ion pair;
• (II) a propylene polymerization catalyst produced by contacting, in any order,
• said propylene polymerization catalyst component as defined in (A) above,
• said at least one compound as defined in (B) above, and (C) an organoaluminum compound;
• (III) a propylene polymerization catalyst produced by contacting, in any order,
• a fine particle carrier,
• said propylene polymerization catalyst component as defined in (A) above, and
• said at least one compound as defined in (B) above,
• wherein said propylene polymerization catalyst as defined in (A) above and said at least one compound as defined in (B) above are supported on said fine particle carrier;
• (IV) a propylene polymerization catalyst produced by contacting
• said propylene polymerization catalyst as defined in (III) above, with
• an organoaluminum compound as defined in (C) above;
• (V) a propylene polymerization catalyst produced by prepolymerizing propylene with said propylene polymerization catalyst as defined in (IV) above;
• and
• (VI) a propylene polymerization catalyst produced by contacting
• said propylene polymerization catalyst as defined in (V) above, with
• an organoaluminum compound as defined in (C) above.