To obtain a polyvinyl alcohol having high syndiotacticity and good quality, properties, etc., from a vinyl ester more simply by polymerizing a vinyl ester in a specified fluorine-containing branched alcohol and saponifying the obtained polymer.
A vinyl ester is polymerized in a fluorine-containing branched alcohol solvent represented by the formula (wherein R1 and R2 are each a fluorohydrocarbon group which may be partially substituted by chlorine atoms; and R3 is a hydrocarbon group, a fluorine atom, a chlorine atom, or a hydrogen atom) and having a pKa of below 4 or above, and the obtained polymer is saponified to obtain a polyvinyl alcohol having a syndiotacticity (diad) of 58% or above. It is desirable that R1, R2, an R3 in the formula are each a 1-3C fluorohydrocarbon group. The fl uorine-containing branched alcohol is desirably perfluoro-tert-butanol, for example. The vinyl ester used is desirably vinyl acetate.
OKAMOTO YOSHIO
NAKANO TAMAKI
SAWAMOTO MITSUO
NAKAJIMA HIROSHI
TERADA KAZUTOSHI
IDA HIROSHI
ASAHI TETSUYA
OKI YASUYOSHI
OKANO YOSHIMICHI
NISHIMURA MASAMICHI
