ALKENYL MODIFIED VINYL ALCOHOL-BASED POLYMER AND THICKENER CONTAINING THE SAME

PROBLEM TO BE SOLVED: To provide a new modified PVA which exhibits sufficient thickening properties and has excellent water solubility.SOLUTION: An alkenyl modified vinyl alcohol-based polymer contains a monomer unit represented by the following formula (I), having a viscosity average degree of polymerization of 100 or more and 5,000 or less, a saponification degree of 20 mol% or more and 99.99 mol% or less, and a content of the monomer unit of 0.05 mol% or more and 5 mol% or less. In the following formula (I), Rrepresents a linear or branched alkenyl group having a carbon number of 8 to 29, and Rrepresents a hydrogen atom or an alkyl group having a carbon number of 1 to 8. The alkenyl group Rin the following formula (I) has a carbon number of, preferably, 15 or more and 26 or less. The saponification degree is preferably 60 mol% or more and 99.9 mol% or less.