Abstract: An ethylene (co)polymer of the present invention is a (co)polymer with excellent moldability and mechanical properties and either an ethylene homopolymer or a copolymer of ethylene and an ?-olefin of 4 to 20 carbon atoms. The (co)polymer has methyl branches measured by 13C-NMR less than 0.1 in number per 1,000 carbon atoms and Mw/Mn measured by GPC not lower than 1.8 and lower than 4.5. The (co)polymer is either an ethylene homopolymer or a copolymer of ethylene and an ?-olefin of 3 to 20 carbon atoms. The melt tension (MT) and the swell ratio (SR) satisfy the relation; log(MT)>12.9?7.15×SR; and the intrinsic viscosity ([?]) and the melt flow rate (MFR) satisfy the relation; [?]>1.85×MFR?0.192 in the case of MFR<1 and the relation; [?]>1.85×MFR?0.213 in the case of MFR?1. Such an ethylene (co)polymer can be usable for various molding applications and especially suitable for pipes.

Abstract: An ethylene (co)polymer of the present invention is a (co)polymer with excellent moldability and mechanical properties and either an ethylene homopolymer or a copolymer of ethylene and an ?-olefin of 4 to 20 carbon atoms. The (co)polymer has methyl branches measured by 13C-NMR less than 0.1 in number per 1,000 carbon atoms and Mw/Mn measured by GPC not lower than 1.8 and lower than 4.5. The (co)polymer is either an ethylene homopolymer or a copolymer of ethylene and an ?-olefin of 3 to 20 carbon atoms. The melt tension (MT) and the swell ratio (SR) satisfy the relation; log(MT)>12.9?7.15×SR; and the intrinsic viscosity ([?]) and the melt flow rate (MFR) satisfy the relation; [?]>1.85×MFR?0.192 in the case of MFR<1 and the relation; [?]>1.85×MFR?0.213 in the case of MFR?1. Such an ethylene (co)polymer can be usable for various molding applications and especially suitable for pipes.

Abstract: An olefin polymerization catalyst having a high polymerization activity at high temperatures and a process for olefin polymerization using the catalyst are disclosed. The olefin polymerization catalyst comprises a transition metal compound which is represented by the following formula (I) and in which the net charge parameter of the central metal is not more than 2.00: wherein M is a transition metal atom of Group 4 to Group 5 of the periodic table, m is an integer of 1 to 5, Q is —N? or —C(R2)?, A is —O—, —S—, —Se— or —N(R5)—, R1 is an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, R2 to R5 are each a hydrogen atom, a hydrocarbon group, an oxygen-containing group or the like, n is a number satisfying a valence of M, and X is a hydrogen atom, a halogen atom, a hydrocarbon group or the like.

Abstract: The present invention provides an olefin polymer having a narrow molecular weight distribution and a specific molecular weight, an olefin polymer having a functional group introduced at the terminal, a tapered polymer containing a segment wherein monomer composition continuously changes in the polymer chain, an olefin polymer having different segments which are bonded to each other, and a process for preparing these polymers. The olefin polymers of the invention are polymers of olefins of 2 to 20 carbon atoms and have a number-average molecular weight of not less than 500 and Mw/Mn of not more than 1.5.

Abstract: The present invention provides an olefin polymer having a narrow molecular weight distribution and a specific molecular weight, an olefin polymer having a functional group introduced at the terminal, a tapered polymer containing a segment wherein monomer composition continuously changes in the polymer chain, an olefin polymer having different segments which are bonded to each other, and a process for preparing these polymers. The olefin polymers of the invention are polymers of olefins of 2 to 20 carbon atoms and have a number-average molecular weight of not less than 500 and Mw/Mn of not more than 1.5.

Abstract: The present invention provides an olefin polymer having a narrow molecular weight distribution and a specific molecular weight, an olefin polymer having a functional group introduced at the terminal, a tapered polymer containing a segment wherein monomer composition continuously changes in the polymer chain, an olefin polymer having different segments which are bonded to each other, and a process for preparing these polymers. The olefin polymers of the invention are polymers of olefins of 2 to 20 carbon atoms and have a number-average molecular weight of not less than 500 and Mw/Mn of not more than 1.5.

Abstract: The present invention provides a novel olefin polymerization catalyst having excellent olefin polymerization activity and, in polymerization with the catalyst comprising a transition metal compound, a polymerization process for preparing a polymer having a low molecular weight with high polymerization activity.

Abstract: An olefin polymerization catalyst having a high polymerization activity at high temperatures and a process for olefin polymerization using the catalyst are disclosed. The olefin polymerization catalyst comprises a transition metal compound which is represented by the following formula (I) and in which the net charge parameter of the central metal is not more than 2.00.