Abstract: A method is disclosed for increasing the productivity of an olefin polymerization catalyst. The catalyst contains an aluminum chloride co-crystallized titanium halide modified with an electron donor containing an ester group. The catalyst component is washed with an olefin, thereby greatly increasing its productivity without significantly adversely affecting the crystallinity of the polymer produced.

Abstract: A catalyst component is a transition metal composition which is obtained by reacting together an inert particulate material, an organic magnesium compound, a halogen-containing compound such as carbon tetrachloride or silicon tetrachloride and a specified transition metal compound. The catalyst component obtained can be used, together with an organic metal compound, to give an olefin polymerization catalyst. The catalyst can be used to effect the polymerization of olefin monomers, for example, the copolymerization of ethylene with an alpha-olefin monomer such as butene-1 in a fluidized bed reactor.

Abstract: Catalysts for the polymerization of ethylene or its copolymerization with C.sub.3 -C.sub.2 alpha-monoolefins are often pre-activated by polymerizing a small amount of C.sub.4 -C.sub.12 alpha-monoolefin onto the catalyst in the presence of an alkyl aluminum compound. The resultant pre-activated catalyst component is used in the form of a dispersion in an inert solvent. The dispersions have a tendency to separate into two phases rapidly and are thus difficult to add uniformly to a polymerization reaction. When the alkyl aluminum compound is replaced by a synergistic mixture of an alkyl aluminum choride and an oxygen-containing aluminum compound having oxygen attached to at least one aluminum valence, a stable dispersion is formed which will not separate into two phases for long periods of time.

Abstract: A process for producing highly crystalline .alpha.-olefin polymers of good particle form with high yield is provided, which comprises polymerizing .alpha.-olefin in the presence of a preactivated catalyst obtained by reacting a reaction product (I) of organoaluminum compound (A.sub.1) with electron donor (B.sub.1), with TiCl.sub.4 to obtain a solid product (II); further reacting (II) with electron donor (B.sub.2) and electron acceptor to obtain a solid product (III); during or/and after the reaction step for obtaining (II) or/and during or/and after the reaction step for obtaining (III), subjecting (II) or (III), to polymerization treatment with .alpha.-olefin; and combining the resulting final solid product with organo-aluminum compound (A.sub.2) and a reaction product (G) of organo-aluminum compound (A.sub.3) with electron donor (B.sub.3) to obtain a preactivated catalyst; and preferably, in this combination, further subjecting a part or the total of the catalyst to polymerization treatment with .alpha.