D Polymer is a PVOH that has highly reactive "carbonyl groups" as a denatured group other than the hydroxyl and acetate groups. The carbonyl group reacts with hydrazide groups and amino groups and in particular it has an especially high reactivity with hydrazide base cross-linking agents, and it can also form coatings and membrane that do not dissolve even in boiling water. It can be used to produce highly transparent gels. DF-05 DF-17 DF-20 Volatile Components (%) 6.0 or less Degree of Hydrolysis (mol%) 98–99 Sodium Acetate (%) 1.5 or less 4% Viscosity (mPa•s) 6±2 23±3 28.5±3 (1) Water-resistant films and coatings (2) Water-based gels (3) Functionality gained from post-denaturing