Patent ID: 8415435

Claim:
A process for producing a conjugated diene-based polymer comprising the following steps (A), (B) and (C): step (A): polymerizing a monomer containing a conjugated diene with an alkali metal catalyst in a hydrocarbon solvent to provide a conjugated diene-based polymer having an alkali metal derived from said catalyst at the end of a polymer chain; step (B): adding a silicon compound expressed by the following formula (III) to a solution of said conjugated diene-based polymer having an alkali metal derived from said catalyst at the end of the polymer chain in a hydrocarbon solvent, so as to react said silicon compound at the end of the polymer chain to produce a conjugated diene-based polymer having a structure, in which the alkali metal derived from said alkali metal catalyst bonds to a constitutional unit based on the silicon compound expressed by the formula (III), at the end of the polymer chain; (wherein X 4 , X 5 and X 6 represent independently a group expressed by the following formula (II) or a hydrocarbon group, and at least one of X 4 , X 5 and X 6 is the group expressed by the formula (II) or a hydroxide group: wherein R 1 and R 2 represent independently a hydrocarbon group having 1 to 6 carbon atoms which can contain a nitrogen atom, an oxygen atom, or a silicon atom, and R 1 and R 2 can be combined to form a ring structure); step (C): adding a monomer containing a conjugated diene to a solution of said conjugated diene-based polymer having a structure, in which the alkali metal derived from said alkali metal catalyst bonds to a constitutional unit based on a silicon compound expressed by the formula (I), wherein X 1 , X 2 and X 3 represent independently a group expressed by the formula (II), a hydroxide group, or a hydrocarbon group, and at least one of X 1 , X 2 and X 3 is the group expressed by the formula (II) or a hydroxide group, at the end of the polymer chain in a hydrocarbon solvent, so as to polymerize said monomer at the end of said polymer chain.