| abstract |
(57) [Problem] To provide a method for producing a block copolymer comprising an α-methylstyrene polymer block and a conjugated diene polymer block. SOLUTION: An organic lithium compound in a non-polar solvent is used as an initiator in the presence of a polar compound at a concentration of 0.1 to 10% by mass at a temperature of -30 ° C to 30 ° C and 5 to 50% by mass. Concentration of α-methylstyrene, and then polymerizing the obtained polymer block A with 1 to 100 molar equivalents of a conjugated diene based on living polyα-methylstyryllithium to form a polymer block B1, A conjugated diene is further polymerized at a temperature exceeding 30 ° C. to form a polymer block B 2. A method for producing a block copolymer, which comprises reacting a polyfunctional coupling agent, if necessary, and hydrogenating after forming 2. |