METHOD FOR PRODUCING ISOBUTYLENE-BASED BLOCK COPOLYMER

摘要

PROBLEM TO BE SOLVED: To provide a method for producing an isobutylene-based block copolymer advantageous in terms of cost with respect to a production process by reducing the amount of a polymerization solvent substantially used and the amount of the waste solvent after polymerization. SOLUTION: In this method for producing an isobutylene-based block copolymer containing an aromatic vinyl-based monomer and isobutylene in a constitutent component, at least one of the polymerization solvent and the unreacted monomer is separated from a mixed solvent solution obtained by removing a polymer from a reaction solution after a polymerization reaction, purified and reused as the polymerization solvent or the monomer to be used in repeatedly producing the isobutylene-based block copolymer.