Patent ID: 6451936
Filing Date: 2002-09-17
Classification: C08F,C08J

Abstract:
A method of producing a polypropylene random copolymer comprising the steps of:copolymerizing propylene and an &agr;-olefin or propylene, ethylene, and &agr;-olefin using a Ziegler-Natta catalyst in a gaseous phase, wherein the propylene content is from 92.3 to 75.0% by weight, the ethylene content (E) is from 0 to 2.7% by weight, and the &agr;-olefin content is from 5.0 to 25.0% by weight, and wherein the content (C) of 20Â° C. xylene-soluble components in the random copolymer satisfies formulae (1) to (3): in the copolymer wherein the ethylene content (E) is less than 1.5% by weight, C&lE;12.0 (weight %)â€ƒâ€ƒ(1) in the copolymer wherein the ethylene content (E) is from 1.5% by weight to 1.8% by weight, C&lE;42.0âˆ’20.0Ã—E (weight %)â€ƒâ€ƒ(2) and in the copolymer wherein the ethylene content (E) is from 1.8% by weight to 2.7% by weight, C&lE;6.0 (weight %)â€ƒâ€ƒ(3); and wherein the Ziegler-Natta catalyst is a catalyst system comprising:(A) solid catalyst components comprising magnesium, titanium and a halogen, (B) an organoaluminum compound, and (C) a silicon compound represented by formula R1R2Si(OR3)2 wherein R1 represents an alicyclic hydrocarbon group having 5 to 20 carbon atoms, and R2 and R3 each represent a hydrocarbon group having 1 to 20 carbon atoms.