PURPOSE: To produce fine polyvinyl alcohol particles which are insol. in cold water and can maintain the state of water dispersion well by saponifying a polyvinyl ester soln. delivered through specific holes.
CONSTITUTION: A vinyl ester soln. with a concn. of 0.5-70wt.% is delivered under a delivery pressure of 0.1-500kg/cm2 through holes with an average diameter of 50μm or lower into air or a poor solvent for the vinyl ester to form liq. polyvinyl ester droplets, which are introduced into a saponification catalyst soln. in a concn. of 0.002-20wt.% and saponified at 20-100°C, thus giving the polyvinyl alcohol particles having a degree of saponification of 70-100mol%, a degree of polymn. of 550-30,000, and an average particle size of 35μm or lower.
TERADA KAZUTOSHI
MARUYAMA HITOSHI
FUKUSHIMA YOSHIBUMI
| JPS37001474B2 | ||||
| JPS4990795A | 1974-08-29 | |||
| JPH05301968A | 1993-11-16 | |||
| JPH06136221A | 1994-05-17 |