| abstract |
In a polymerization process of at least one of monomers selected from the group consisting of conjugated diene compounds such as butadiene and vinylaromatic compounds such as styrene, an organolithium compound such as butyllithium is added to the polymerization system first in the presence of the monomer, and thereafter a secondary amine compound such as saturated cyclic imine is added thereto to produce a soluble initiator by bringing the both compound into contact with each other. Polymerization is carried out with the soluble initiator formed. The obtained high molecular weight polymer is modified with a coupling agent such as tin tetrachloride. The polymer obtained has a high molecular weight, a narrow molecular weight distribution, and controlled molecular weight, and exhibits remarkable coupling property, low hysteresis loss. The process provides a polymer having a consistent characteristic, regardless of production scale and procedures of adding materials. |