| abstract |
Is obtained by emulsion polymerization using 2,2,4,6,6-pentamethylheptane-4-thiol as a chain transfer agent, and provides a nitrile copolymer rubber having a polymer pH of 8.5 or less. The polymer pH is preferably 8.0 or less. According to the present invention, there can be provided a nitrile copolymer rubber capable of imparting a rubber cross-linked product excellent in heat resistance and compression set resistance. |