| 摘要 |
PURPOSE:To obtain polymer particles with few fine particles and narrow particle diameter distribution by decreasing a stirring power requirement per unit vol. of a polymn. tank at two specified stages in the progress of the polymn. when a vinyl monomer is suspension-polymerized. CONSTITUTION:A vinyl monomer (e.g. styrene), an anionic surface active agent, an aq. medium, a polymn. initiator, etc., are fed to a polymn. tank and heated at a specified temp. while stirring to start a suspension polymn. The stirring power requirement per unit vol. of the polymn. tank is decreased to 90-18% of the initial value while the polymn. conversion is 20-50% and the polymn. is advanced by using this power as the second stirring power requirement. Then, while the polymn. conversion is in the range of 50-70%, the stirring power requirement per unit vol. of the polymn. tank is decreased to 50-5% of the second stirring power and the polymn. is furthermore advanced. Vinyl polymer particles with few fine particles of smaller than 250mum and a narrow particle diameter distribution can be thereby prepd. and the processability in the production and utilization of the beads are improved. |
