Patent ID: 8513368

Claim:
A copolymer obtained by copolymerizing at least ethylene and a conjugated diene, wherein (1) structural units derived from the conjugated diene represent 1 to 90 mol % of all the monomer units in the copolymer, and (2) based on all the structural units derived from the conjugated diene in the copolymer, structural units resulting from 1,2-addition of the conjugated diene and having a side-chain double bond represent 0.5 to 90 mol %, structural units resulting from 1,4-addition of the conjugated diene represent 0 to 3 mol %, structural units resulting from 1,3-addition of the conjugated diene represent 0 to 3 mol %, and the total of structural units resulting from 1,2-addition of the conjugated diene and having a 1,2-cyclopropane skeleton and structural units resulting from 1,2-addition of the conjugated diene and having a 1,2-cyclopentane skeleton represent 4 to 99.5 mol %.