In the case of conventional fully hydrolyzed PVOH, although the mechanical properties like film strength tends to be better but its aqueous solution easily form gel during the storage at low temperature. Fully hydrolyzed type HP-Polymer solution can be stored at low temperature without gelation, even it has same mechanical properties with conventional fully hydrolyzed PVOH. The following figures show the viscosity stability of HP-Polymer solution, compared with those of conventional PVOH. PVA-117 is conventional fully hydrolyzed PVOH and it has good mechanical properties, however it does not have enough solution stability. PVA-217 is conventional partially hydrolyzed PVOH and has good solution stability but its mechanical properties tend to be worse. HP-Polymer provides both good mechanical properties and sufficient stable solution. In addition HP-Polymer can come through the demand for increasing the concentration of its solution. Solution at low temperature. Upper : Conventional PVOH Lower : HP-POLYMER solution HP-POLYMER solution has a better stability low temperature.