Abstract: [Problem] To efficiently obtain an ?-olefin polymer having a high melting point and a high molecular weight. [Solution to Problem] The process for preparing an olefin polymer of the present invention is a process for preparing an olefin polymer, comprising polymerizing at least one monomer selected from ?-olefins of 2 or more carbon atoms, wherein the polymerization is carried out at a temperature of not lower than 40° C.

Abstract: Disclosed is a method for producing a syndiotactic propylene polymer having a syndiotactic pentad fraction (rrrr fraction) of not less than 85%, a melting point (Tm) within the range of 145-170° C. and a limiting viscosity [?] within the range of 0.1-10 dl/g by a solution polymerization method using a group 4 crosslinked metallocene compound, which is not accompanied by precipitation of a polymer (excluding white turbidity). Also disclosed is a production method which enables to continuously perform such a production.

Abstract: It is an object of the present invention to provide a process for producing a syndiotactic propylene polymer with high polymerization activity and high efficiency by a solution polymerization method without deposition of polymers (excluding a white state), and a production process capable of conducting the above production continuously, provided that these processes could not be attained conventionally. The present invention is: a process for producing a syndiotactic propylene polymer having a syndiotactic pentad fraction (rrrr fraction), as measured by 13C-NMR, of at least 85%, a melting point (Tm), as measured by DSC, of from 145° C. to 170° C., and an intrinsic viscosity [?] of 0.1 to 10 dl/g, which process comprises a step (P1) of solution polymerizing propylene singly or propylene and at least one monomer selected from ethylene and an ?-olefin having 4 to 10 carbon atoms at a polymerization temperature (TR) of from 30° C. to 250° C.