| 摘要 |
PROBLEM TO BE SOLVED: To provide a vinyl acetal-based polymer having excellent handleability which is excellent in solubility to an alcoholic solvent and a low polar solvent and in which the viscosity of a solution obtained by dissolving the vinyl acetal-based polymer in these solvents is suppressed low, and further to provide a vinyl acetal-based polymer having an adequately low elastic modulus even without containing a plasticizer and has no yield point in a low elongation region.SOLUTION: There is provided a vinyl acetal-based polymer which is obtained by acetalization of a hydroxymethyl group-containing vinyl acetal-based polymer having 0.1 to 30 mol% of a structural unit represented by the formula (1) and has an acetalization degree of 45 to 90 mol%. |
