| abstract |
A nitrile group-containing highly saturated copolymernrubber comprising (a) 0 to 20% by weight of 1,3-butadiene units,n(b) 0 to 50% by weight of saturated 1,3-butadiene units, (c)n40 to 50% by weight of α,β-ethylenically unsaturated nitrilenmonomer units, and (d) 10 to 35% by weight and at least 8% bynmol of other monomer units, wherein the sum of 1,3-butadienenunits (a) and saturated 1,3-butadiene units (b) is in the rangenof 20 to 50% by weight. A rubber composition comprising thisncopolymer rubber and a crosslinking agent gives a crosslinkednproduct exhibiting good oil resistance, namely, good resistancento rancid gasoline and not hardening even when it is placed inncontact with oil containing condensed aromatics. |