Patent ID: 8283401

Claim:
A method of manufacturing a conjugated diene polymer, comprising polymerizing a conjugated diene at 60 to 120° C. in the presence of a catalyst obtained from (A) an yttrium compound, (B) an ionic compound consisting of a non-coordinating anion and a cation, and (C) an organoaluminum compound, wherein the conjugated diene polymer has the following characteristics that: (1) a ratio (T cp /ML 1+4 ) between a 5 wt % toluene solution viscosity (T cp ) measured at 25° C. and a Mooney viscosity (ML 1+4 ) at 100° C. is 0.1 to 1.2; and (2) a content of cis-1, 4 structures is 80% or higher, and a content of 1,2 structures is lower than 5%.