BUTADIENE POLYMER AND PROCESS FOR PRODUCING THE SAME, AND RUBBER COMPOSITION AND TIRE COMPRISING OR MADE FROM THE SAME

摘要

A butadiene polymer which has a high content of cis-1,4 bonds and a low content of vinyl bonds and has a molecular-weight distribution in a specific range. The butadiene polymer, which contains 1,3-butadiene monomer units, is characterized in that the 1,3-butadiene monomer units have a cis-1,4 bond content and a vinyl bond content, as determined by Fourier transform infrared spectroscopy, of 98.0% or higher and 0.3% or lower, respectively, and that the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), (Mw/Mn), is from 1.6 to 3.5.