Process for producing block copolymer, and block copolymer or hydrogenated product thereof

Abstract

The present invention provides a process for producing a block copolymer in high productivity, by anionic polymerization by use of a lithium initiator, and also to provide the block copolymer and a hydrogenated product thereof, the block copolymer having a conjugated diene block portion with a high vinyl bond content and a vinyl aromatic block portion with a narrow molecular weight distribution and exhibiting a narrow molecular weight distribution and high strength. A conjugated diene monomer and a vinyl aromatic monomer by use of a lithium initiator, are block copolymerized by making a tertiary amine compound and (2) sodium alkoxide coexist, wherein (2)/(1) (a molar ratio)=from 0.01 or more to less than 0.1.

Dependencies are inferred from the claim text.