Abstract: A method for producing a polyolefin in the presence of a catalyst comprising a transition metal compound and an organometallic compound, wherein a catalyst system is used which comprises: (A) a solid catalyst component prepared by reacting a uniform solution containing (I) at least one member selected from the group consisting of metal magnesium and a hydroxylated organic compound, and oxygen-containing organic compounds of magnesium, (II) an electron donative compound and (III) an oxygen-containing organic compound of titanium, with (IV) at least one aluminum halide compound to obtain a solid product, adding to this solid product (V) at least one compound selected from the group consisting of oxygen-containing organic compounds of one or more transition metals of Group IVa of the Periodic Table, and then treating the mixture with (VI) an aluminum halide compound, and (B) at least one catalyst component selected from the group consisting of organoaluminum compounds.

Abstract: A manufacturing method of polyolefin is disclosed wherein the catalyst used for the polymerization of .alpha.

Abstract: A catalyst comprising (A) a solid catalyst component obained by reacting a homogeneous solution containing (i) at least one member selected from the group consisting of a combination of metallic magnesium and a hydroxyl organic compound, and an oxygen-containing organic compound of magnesium, (ii) an electron donor compound and (iii) an oxygen-containing organic compound of titanium with (iv) at least one aluminum halide compound and further reacting the obtained solid product with (v) an electron donor compound and (vi) a titanium halide compound, (B) at least one member selected from the group consisting of organic metal compounds of metals of the groups Ia, IIa, IIb, IIIb and IVb of the periodic table, and (C) an electron donor compound, is valuable as the catalyst for preparing a stereoregular polyolefin by homopolymerization or copolymerization of an .alpha.-olefin having at least 3 carbon atoms.

Abstract: A manufacturing method of polyolefin characterized in that at least one kind of olefins is allowed to polymerize in the presence of a catalyst system comprising(A) solid catalyst ingredient (A) obtained through the successive reaction steps, wherein, with a homogeneous solution involving(i) at least one member selected from metallic magnesium and hydroxylated organic compounds and oxygen-containing organic compounds of magnesium, and(ii) at least one kind of oxygen-containing organic compounds of titanium, are allowed to react in sequence with:(iii) at least one kind of organoaluminum compounds, then(iv) at least one kind of silicon compounds and further(V) at least one kind of halogenated aluminum compounds and(B) at least one kind of catalyst ingredients (B) selected from organometallic compounds, the metal of which belongs to Ia, IIa, IIb, IIIb or IVb group in the periodic table.