| abstract |
PURPOSE: The titled polymer improved in roll windability and extrusion mark without detriment to hysteresis loss and breaking characteristics, comprising a specified branched polymer and a specified amount of a specified low-MW polymer. n CONSTITUTION: The titled polymer comprising a butadiene polymer prepared by polymerizing 1,3-butadiene or copolymerizing 1,3-butadiene with an aromatic vinyl compound with the aid of an organometallic compound as an initiator in the presence of a Lewis acid in a hydrocarbon solvent, and containing a branched polymer whose bond in its branched portion is a tin-carbon bond, wherein said butadiene polymer contains 10W20wt% components having a bound vinyl aromatic compound content of 0W40wt%, a vinyl bond content of the butadiene portion of 30W90%, and a proportion of the branched polymer of above 30wt%, and a MW of below 10×10 4 (in terms of PS) in an MW distribution determined by gel permeation chromatography. n COPYRIGHT: (C)1984,JPO&Japio |