Polyvinyl alcohol and gel therefrom

摘要

The present invention is to provide a polyvinyl alcohol containing the structural unit (I) of the following formula (I) at a molar fraction of 0.05 to 0.50 and the structural unit (II) of the following formula (II) at a molar fraction of 0.0001 to 0.50; wherein R<1> is hydrogen atom or a mono-valent hydrocarbon group; and R<2> and R<3> are mono-valent hydrocarbon groups or R<2> and R<3> together form a ring; or R<1>, R<2> and R<3> together form a ring; X is a group represented by the formula -CO-Y, -Y or -CO-COOH (wherein Y represents a hydrocarbon group directly or indirectly bonded with carboxyl group, sulfo group, amino group and/or phosphonooxy group) or X forms phosphonooxy group together with the oxygen atom to which X is bonded.