| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a polymer, by which variation among lots of the polymer can be further reduced.SOLUTION: A method for producing a polymer includes: a polymerization step of supplying a polymerization solvent, a monomer and a polymerization initiator into a reaction vessel and polymerizing the monomer in a reaction liquid in the reaction vessel; and a reaction termination step of terminating the polymerization reaction. The method also includes a monomer supply step of continuously supplying or dropping the monomer into the reaction vessel, in a polymerization reaction period from a time when the polymerization reaction is started to a time when a termination operation is started. The temperature of the reaction liquid in a monomer supply period from the start to the end of the monomer supply step is maintained within the range of an average temperature of the reaction liquid in the monomer supply period ±1.5°C. The proportion of the total mass of the monomer supplied to the inside of the reaction vessel is controlled to less than 30 mass% with respect to the mass of the reaction liquid at the end of the polymerization reaction period, and the monomer supply period occupies 70% or more of the polymerization reaction period. |
