The present invention relates to a method for preparing a high 1,4-cis polybutadiene
having a controlled cold flow and, more particularly, to a novel method for preparing
a high 1,4-cis polybutadiene having a controlled cold flow that involves initiating
polymerization of a 1,3-butadiene in the presence of a non-polar solvent using,
as a polymerization catalyst, a complex prepared by mixing a neodymium compound
with or without a conjugated diene compound, a halogenated organoaluminum compound
or a halogenated organic compound, and an organoaluminum compound irrespective
of the addition order of the catalyst; and adding an organoborane compound as a
cold flow controller of 1,4-cis polybutadiene after a predetermined time of the
polymerization. Accordingly, a high 1,4-cis polybutadiene having an efficiently
controlled cold flow can be prepared without causing a significant increase in
the Mooney viscosity (molecular weight), an odor (bad smell), and a reduction in
1,4-cis content and polymerization yield.
