HIGHLY SATURATED COPOLYMER RUBBER CONTAINING NITRILE GROUP, CROSS-LINKABLE RUBBER COMPOSITION COMPRISING SAME, AND CROSS-LINKED PRODUCT

摘要

Disclosed is a highly saturated copolymer rubber containing a nitrile group, which comprises 10 to 60 wt% of an a,ß-ethylenically unsaturated nitrile monomer unit (a), 0.1 to 20 wt% of a monobutyl maleate unit (b1) and/or a monobutyl fumarate unit (b2), and a conjugated diene monomer unit (c) and a saturated conjugated diene monomer unit (d) in the total amount of 20 to 89.9 wt%, wherein the content of the monomer unit (d) relative to the total content of the monomer unit (c) and the monomer unit (d) is 70 wt% or more.  The highly saturated copolymer rubber containing a nitrile group has a difference between the extrapolated onset temperature for glass transition (Tig) and the extrapolated end temperature for glass transition (Teg) of 5 to 11°C as measured by differential scanning calorimetry.