Method for manufacturing polymer and flow-type reaction system for manufacturing polymer

A method for manufacturing a polymer by performing an anionic polymerization reaction by a flow-type reaction, comprising:

• introducing a liquid A containing an anionic polymerizable monomer, a liquid B containing an anionic polymerization initiator, and a polymerization terminator into different flow paths respectively and causing the liquids to flow in the respective flow paths;
• causing the liquid A and the liquid B to join together by using a multilayered cylindrical mixer, wherein the multilayered cylindrical mixer comprises a smallest cylinder and an adjacent cylinder which is adjacent to the smallest cylinder, the interior of the smallest cylinder defines an internal flow path and a portion between the smallest cylinder and the adjacent cylinder defines an adjacent flow path, the liquid A and the liquid B join together in a joining portion, wherein the joining portion is in a terminal portion of the smallest cylinder and is disposed in the adjacent cylinder;
• subjecting the anionic polymerizable monomer to anionic polymerization while a solution formed by the joining is flowing to downstream in a reaction flow path;
• and
• causing the solution, which has undergone the polymerization reaction and flows in the reaction flow path, and the polymerization terminator to join together such that the polymerization reaction is terminated,
• wherein a liquid flowing in the internal flow path has a linear velocity r1 and a liquid flowing in the adjacent flow path has a linear velocity r2, and a value of a ratio of r2 to r1 satisfies the following Expression (I) or (II):
• r2/r1≤0.67 (I)
• r2/r1≥1.5 (II)
• here, any one of the liquid flowing in the internal flow path or the liquid flowing in the adjacent flow path is the liquid A, and the other is the liquid B.