| abstract |
[PROBLEMS] To provide an α-olefin / conjugated diene copolymer excellent in cold resistance and excellent in crosslinking efficiency and modification efficiency. A copolymer comprising an α-olefin having 2 to 12 carbon atoms and a conjugated diene monomer represented by the following formula (Ia), wherein (a) in the copolymer: The 1,2 adduct (including the 3,4 adduct) derived from the conjugated diene monomer (Ia) forms a double bond in a side chain in the copolymer. The 4-adduct forms a double bond in the main chain in the copolymer, and the double bond in the side chain derived from the above 1,2 adduct and the double bond in the main chain derived from the 1,4 adduct. (B) having a five-membered ring in the main chain of the copolymer, and (c) having a double bond and a five-membered ring of the above all adduct. Ratio ( total double bonds of all adducts / 5 Member ring) is 20/80 to 90/10 [In the formula (Ia), R 2 is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or an aryl group. ]. |