Abstract: A process for production of an olefin polymer is provided which comprises polymerization of ethylene and/or &agr;-olefin of three of more carbons at a polymerization temperature of not lower than 120° C. with a catalyst comprising a specific metallocene compound having a substituted fluorenyl group, and a compound which reacts with the metallocene compound to form a cationic metallocene compound. The olefin polymer or copolymer produced by the process has narrow composition distribution, narrow molecular weight distribution, and a high molecular weight.

Abstract: A process for production of an olefin polymer is provided which comprises polymerization of ethylene and/or &agr;-olefin of three of more carbons at a polymerization temperature of not lower than 120° C. with a catalyst comprising a specific metallocene compound having a substituted fluorenyl group, and a compound which reacts with the metallocene compound to form a cationic metallocene compound. The olefin polymer or copolymer produced by the process has narrow composition distribution, narrow molecular weight distribution, and a high molecular weight.

Abstract: A process for producing an ethylene/&agr;-olefin copolymer is provided in which ethylene is copolymerized with an &agr;-olefin having three or more carbons by use of an olefin polymerization catalyst at a polymerization temperature of not lower than 120° C. The olefin polymerization catalyst comprises, as constitutional components, a) a metallocene compound comprising hafnium, b) an ionizing ionic compound, and c) an organoaluminum compound, the ionizing ionic compound (b) being a compound which is capable of changing the metallocene compound (a) into a cationic form and does not further react the cationic form of the metallocene compound.

Abstract: An ethylene/&agr;-olefin copolymer of a weight-average molecular weight of not less than 40000 is produced by copolymerization of ethylene with an &agr;-olefin having three or more carbons by use of an olefin polymerization catalyst at a polymerization temperature of not lower than 120° C., the olefin polymerization catalyst comprising, as constitutional components, a) a metallocene compound, b) an ionizing ionic compound, and c) an organoaluminum compound, the ionizing ionic compound (b) being a compound which is capable of changing the metallocene compound (a) into a cationic form and does not further react the cationic form of the metallocene compound. This process produces an ethylene/&agr;-olefin copolymer of high molecular weight in high efficiency.

Abstract: A catalyst for polymerization of an olefin is provided which comprises a metallocene compound having a specified substituted fluorenyl group, and a compound capable of reacting the metallocene compound to form a cationic metallocene compound. With this compound, a high-molecular olefin polymer having narrow composition distribution and narrow molecular-weight distribution can be obtained at a polymerization temperature of not lower than 120.degree. C.

Abstract: Novel catalysts for polymerization of ethylene or .alpha.-olefins, comprising a metallocene, an organoaluminum compound an ionic compound, and a boron compound, or comprising an ionic metallocene, an organoaluminum compound and a boron compound. Process for polymerization of ethylene or .alpha.-olefins by use of the above catalysts.

Abstract: A transition metal organometallic compound comprising a transition metal in any one of group 3A to group 8 of the periodic table and cyclic compounds containing a heteroaom in group 5 or group 5B of the periodic table and having a cyclic structure including a .pi.-bonded portion and composed of said heteroatom and said .pi.-bonded portion, wherein said transition metal has a bond of a .pi.-binding heterocylic ligand, said heteroatom and said .pi.-bonded portion and a catalyst for polymerizing olefin comprising the above organic metal compound and an organic compound.