Ethylene-.alpha.-olefin-nonconjugated polyene random copolymer, rubber composition, and process for preparing the random copolymer

Abstract

Disclosed is an ethylene-.alpha.-olefin-nonconjugated polyene random copolymer which is a random copolymer of (a) ethylene, (b) an .alpha.-olefin of 3 or more carbon atoms and (c) a nonconjugated polyene, and has such properties that (i) the copolymer contains (a) units derived from ethylene and (b) units derived from the .alpha.-olefin of 3 or more carbon atoms in a molar ratio of 40/60 to 95/5 ((a)/(b)), (ii) the iodine value is in the range of 1 to 50, (iii) the intrinsic viscosity (.eta.), as measured in decahydronaphthalene at 135.degree. C., is in the range of 0.1 to 8.0 dl/g, and (iv) the ratio g.eta.* of the intrinsic viscosity (.eta.) of the copolymer defined above to the intrinsic viscosity (.eta.).sub.blank of a linear ethylene-propylene copolymer having the same weight-average molecular weight as the ethylene-.alpha.-olefin-nonconjugated polyene random copolymer and having an ethylene content of 70% by mol, (.eta.)/(.eta.).sub.blank, is in the range of 0.2 to 0.9 or the ratio g' of the intrinsic viscosity (.eta.) of said random copolymer defined above to the intrinsic viscosity (.eta.).sub.blank' of a linear ethylene-propylene copolymer having an ethylene content of 70% by mol which is determined by measurement of gel permeation chromatography (GPC) of ethylene-.alpha.-olefin-nonconjugated polyene random copolymer in orthodichlorobenzene at 140.degree. C., (.eta.)/(.eta.).sub.blank', is in the reange of 0.2 to 0.9.

Dependencies are inferred from the claim text.