Patent ID: 6995228

Claim:
A cyclic conjugated diene copolymer comprising a main chain represented by the following formula (1): [ A l B m C n —] (1) wherein A, B and C are monomer units constituting said main chain in which monomer units A, B and C are arranged in any order, and l, m and n are, respectively, weight percentages of monomer units A, B and C, based on the total weight of monomer units A, B and C; wherein: each A is independently selected from the group consisting of cyclic conjugated diene monomer units, each B is independently selected from the group consisting of monomer units obtained from vinyl aromatic monomers each having a hydrogen atom at the α-position thereof, and each C is independently selected from the group consisting of monomer units obtained from comonomers which are other than the monomers used for obtaining said monomer units A and B and which are copolymerizable with at least one of the monomers used for obtaining said monomer units A and B; wherein said cyclic conjugated diene copolymer has a side chain; and wherein: l, m and n satisfy the following requirements: l+m+n= 100, 0.1≦l/m≦9, and 0≦n≦90, with the proviso that all monomer units A and said monomer units B together form one or more polymer chains each having an A/B random sequence, said one or more polymer chains each having an A/B random sequence containing at least one polymer chain having a number average molecular weight of from 20,000 to 500,000 and containing no polymer chain having a number average molecular weight of more than 500,000.