| 摘要 |
PURPOSE:To obtain the titled polymers, having a specific intrinsic viscosity value or above and a high polymerization degree, and useful as a raw material for polyvinyl alcohol (PVA) of high performance with good uniformity easily on an industrial scale, by suspension polymerizing a vinyl ester monomer at a specific polymerization temperature and polymerization rate. CONSTITUTION:A vinyl ester monomer, e.g. vinyl acetate, is suspension polymerized at <=20 deg.C polymerization temperature and <=10%/hr polymerization rate to give a polyvinyl ester based polymer having a high polymerization degree and >=1.5 intrinsic viscosity (which is defined as a value obtained by saponifying the polymer, reacetating the saponified polymer, and measuring the value of the polyvinyl acetate in acetone at 30 deg.C). The resultant polymer is then saponified to afford a polyvinyl alcohol based polymer having a high polymerization degree and >=1.5 intrinsic viscosity. |
