Process for polymerization of .alpha.-olefin

Abstract

There is provided a process for polymerization of an .alpha.-olefin which comprises polymerizing an .alpha.-olefin in the presence of a catalyst which is a combination of a solid component (A), which is obtained by subjecting a composition (A.sub.O) comprising as the essential ingredients titanium, magnesium and a halogen to preliminary polymerizatoin of the .alpha.-olefin conducted in the presence of said composition in a slurry and an organoaluminum compound, and an organoaluminum compound (B), said preliminary polymerization being conducted in two steps: the first step wherein the concentration of said composition (A.sub.O) in the slurry is adjusted to 10-100 g/lit.-solvent and polymerization of the .alpha.-olefin is conducted at 30.degree. C. or lower so that the amount of a polymer produced is 0.001 to 1 g per gram of said composition and the second step wherein polymerization of the .alpha.-olefin is conducted at 60.degree. C. or higher under the same condition of the concentration of said composition as in the first step so that the amount of a polymer produced is 1 to 10 g per gram of said composition. According to this process, an .alpha.-olefin is polymerized at a possible elevated temperature and an .alpha.-olefin polymer having high stereoregularity, excellent polymer properties and improved odor is produced in a high yield.