PURPOSE: To obtain a conjugated diene-polymerizing method whereby polymer particles with constant m.p. and particle size distribution are obtd. even when a dispersion medium is used repeatedly by recovering the medium after the polymn. and specifically treating it.
CONSTITUTION: A conjugated diene is polymerized in suspension in a dispersion medium contg. water in the presence of a catalyst comprising carbon disulfide and a soln. which is obtd. by bringing a transition metal compd. into contact with an organometallic compd. of a group I-III metal in the presence of a conjugated diene and aging the resulting product. After the polymn., the medium is recovered, adjusted to substantially the same concn. as during the polymn. by adding the fresh dispersion medium and/or water, and used again for the polymn. When polyvinyl alcohol is used as a dispersant, the addition of sodium borate is pref. Sodium borate, which may be added before the polymn., is pref. added in an amt. of 5-1,000 pts.wt. (based on 100 pts.wt. polyvinyl alcohol in the medium after adjusted about the concn).
MOTOYUKI KANICHI
BABA YOSHIMOTO
SUZUKI MICHINORI
AKIGAWA KAZUHIRO
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