| abstract |
A nitrile copolymer rubber which comprises 10-40 wt.% α,β-ethylenically unsaturated nitrile units (a), 10-60 wt.% α,β-ethylenically unsaturated carboxylic ester units (b), and 20-70 wt.% the sum of conjugated diene units (c) and saturated conjugated diene units (d), wherein the proportion of the content of the conjugated diene units (c) to the total content of the conjugated diene units (c) and the saturated conjugated diene units (d), x, is 0.08 or lower and the product of the proportion x and the content A [%] of the α,β-ethylenically unsaturated nitrile units (a), x·A, is 1.5 or smaller. The nitrile copolymer rubber can give a vulcanized rubber having a high degree of balance among mechanical strength, resistance to thermal deterioration, oil resistance, cold resistance, and ozone resistance. Also provided is a vulcanizable rubber composition containing the rubber. |