PURPOSE: To produce a copolymer excellent in transparency and stiffness and useful for a film, etc., by copolymerizing a specified ratio of propylene and ethylene in the presence of a specified polyinerization catalyst component.
CONSTITUTION: (D) An olefin is brought into contact with (A) a solid catalyst component composed essentially of magnesium such as dimethylmagnesium, titanium such as titanium tetrachloride, a halogen such as methyl chloride and an electron donative compound such as butyl formate in the presence of (B) an organoaluminium compound such as trimethylaluminium and (C) an organosilicon compound of the formula [R1 is a silicon atom-containing heterocyclic substituent group; R2 is a 1 to 10C hydrocarbon, R4O, R53Si or R63SiO (R4 is a 3 to 10C hydrocarbon; R5 and R6 are each R2); R3 is methyl or ethyl; (x) is 1 or 2; (y) is 0 or 1; (z) is 2 or 3] to prepare a polymerization catalyst component. Propylene and ethylene are copolymerized in the presence of this polymerization catalyst component, thus producing the objective copolymer of 0.01 to 10wt.% ethylene content.
OKURA MASATOSHI
ISHIHARA TAKESHI
NAKAJIMA MASASHI
KANAZAWA SEIZABURO
