| 摘要 |
PROBLEM TO BE SOLVED: To provide: a copolymer in which dispersibility of a filler such as carbon black and silica can be improved when being used for a part of a rubber composition; the rubber composition that includes the copolymer, in which processability is excellent when being combined, being molded and being subjected to vulcanization, that has excellent rolling resistance performance and abrasion resistance, and that can control decrease of mechanical strength and hardness; and a tire using the rubber composition.SOLUTION: A copolymer contains a monomer unit (a) derived from isoprene, and a monomer unit (b) derived from farnesene. A method for producing the copolymer involving copolymerization of at least isoprene and farnesene. A rubber composition contains the copolymer (A), a rubber component (B) and carbon black (C). A rubber composition contains the copolymer (A), a rubber component (B) and silica (D). A rubber composition contains the copolymer (A), a rubber component (B), carbon black (C) and silica (D). A tire has at least one part where the rubber composition is used. |
