Modified Conjugated Diene Polymer, Polymerization Intitiator, Method of Producing the Same, and Rubber Composition

Preparation of Polymerization Initiator Solution A

[0103]In a Kjeldahl flask of 100 mL provided with Teflon (registered trademark) agitator and sufficiently dried is charged 5.75 mmol of N,N′-dimethyl-1,6-diaminohexane under a stream of an inert gas, which is dissolved in 10 mL of tetrahydrofuran. Then, 5.75 mmol of n-butyllithium is added dropwise to the resulting solution while violently stirring with a magnetic stirrer. The solution is added with 5.75 mmol of chlorotrimethylsilane and stirred at room temperature for 30 minutes. After the resulting solid is filtered off through a PTFE filter, 15 mL of a filtrate is charged into a sufficiently dried pressure glass bottle of 150 mL, which is closely sealed with a crown cap provided with a rubber stopper. To this solution are successively added 4.23 mmol of tetramethylethylene diamine and 4.23 mmol of n-butyllithium, which are sufficiently stirred to obtain a polymerization initiator solution A.

Synthesis of Polymer A

[0104]Into a pressure

Synthesis of polymer E

[0112]A polymer E is synthesized in the same manner as in the synthesis of the polymer A except that 0.19 mmol of tin tetrachloride is added instead of the isopropanol solution of BHT and further the modification reaction is carried out at 50° C. for 30 minutes and thereafter the isopropanol solution of BHT is added.