Ethylene/alpha-olefin/unconjugated polyene copolymer rubber, rubber composition for sealing, molded rubber for sealing, and process for producing the molded rubber

摘要

The present invention relates to an ethylene-alpha-olefin-non-conjugated polyene copolymer rubber comprising ethylene, an alpha-olefin having 3 to 20 carbon atoms and a non-conjugated polyene, characterized in that:(i) the intrinsic viscosity [eta] as measured in decalin solvent at 135° C. is 1.5 to 5.0 dl/g;(ii) the geta* or g' value is 0.6 to 0.9;(iii) the Mw/Mn is 3.0 to 50;(iv) the iodine value is 10 to 40;(v) the molar ratio of ethylene to the alpha-olefin having 3 to 20 carbon atoms is 40/60 to 95/5; and(vi) the intensity ratio D of Talphabeta to Talphaalpha in 13C-NMR spectrum (Talphabeta/Talphaalpha) is 0.5 or less, as well as to a rubber composition for sealing using said copolymer rubber, a molded rubber part for sealing, and a process for preparing said molded part.