Patent ID: 7056994

Claim:
A production method of polymer of conjugated dienes comprising: reacting conjugated dienes with a catalyst composition for polymerization of a conjugated diene, comprising: (A) a metallocene complex represented by a general formula (I): (C 5 R 1 R 2 R 3 R 4 R 5 ) a MX b .L c wherein M represents a rare earth metal; C 5 R 1 R 2 R 3 R 4 R 5 represents a substituted cyclopentadienyl group selected from a 1-ethyl-2,3,4,5-tetramethylcyclopentadienyl group, a 1-isopropyl-2,3,4,5-tetramethylcyclopentadienyl group, a 1-n-butyl-2,3,4,5-tetramethylcyclopentadienyl group, a 1-trimethylsilyl-2,3,4,5-tetramethylcyclopentadienyl group, a 1-benzyl-2,3,4,5-tetramethylcyclopentadienyl group, a 1-phenyl-2,3,4,5-tetramethylcyclopentadienyl group, a 1-trifluoromethyl-2,3,4,5-tetramethylcyclopentadienyl group, a 1-isobutyl-2,3,4,5-tetramethylcyclopentadienyl group, a 1-triethylsilyl-2,3,4,5-tetramethylcyclopentadienyl group, and a 1-triisopropylsilyl-2,3,4,5-tetramethylcyclopentadienyl group; X represents a hydrogen atom, a halogen atom, an alkoxide group, a thiolate group, an amide group, or a hydrocarbon group having 1 to 20 carbon atoms; L represents a Lewis basic compound; “a” represents an integer of 1 or 2; “b” represents an integer of 0, 1, or 2; and “c” represents an integer of 0, 1, or 2; and (B) an ionic compound composed of a non-coordinating anion and a cation, and/or an aluminoxane, wherein the polymerization reaction is performed in the presence of cyclohexane.