POLYVINYL ALCOHOLIC POLYMER AND POWDER COMPRISING THE POLYMER

摘要

PROBLEM TO BE SOLVED: To provide a polyvinyl alcoholic polymer having a high crystallinity, and further to provide a polyvinyl alcoholic powder comprising the polymer. SOLUTION: This polyvinyl alcoholic polymer is obtained by introducing an azo-based compound catalyst having <=64 deg.C half life temperature by 10 hr to a polymerization system while keeping the temperature at the temperature >=10 deg.C lower than the half life temperature to polymerize (1) vinyl acetate or (2) the vinyl acetate and other unsaturated monomers to provide a polyvinyl acetate-based polymer, and saponifying the resultant polyvinyl acetate-based polymer.