To obtain a butadiene polymer having a narrow molecular weight and a high 1,4-cis bond content and to provide a method for producing the butadiene polymer.
This butadiene polymer having ≤1.5 Mw/Mn and ≥96 mol% 1,4-cis bond content is obtained by polymerization at a specific polymerization temperature by using a catalyst obtained by previously preparing a transition metal compound (A) of the group IV of the periodic table having a cyclopentadienyl skeleton containing an ether group-containing substituent and at least one kind of a cocatalyst selected from an organoaluminum oxy- compound (B1), an ionic compound (B2), a Lewis acid (B3) and an organometallic compound composed of a metal of the groups I to III of the periodic table under specific aging conditions.
ASAI MICHIHIKO
SUZUKI YASUZO
MIYAZAWA SATORU
TSUCHIHARA KENJI
MURATA MASAHIDE
OZAKI HIROYUKI
KAWABE MASANAO
FUKUI YOSHIFUMI
JIN JIJU
HAGIWARA HIDEAKI
KASE TOSHIO
JAPAN CHEMICAL INNOVATION INST
Uchida Yukio
Next Patent: METHOD FOR PRODUCING PROPYLENE-ETHYLENE RANDOM COPOLYMER