| 摘要 |
PROBLEM TO BE SOLVED: To provide a modified polyvinyl alcohol having phosphoric acid parts introduced in polyvinyl alcohol in a high introduction ratio under a mild condition and by simple reaction equipment, the modified polyvinyl alcohol being able to be used as is as an adhesive, a dispersant for emulsion polymerization, a water retention agent for agriculture, a water-soluble film, and the like without chemically treating the phosphoric acid group.SOLUTION: Provided is a modified polyvinyl alcohol containing 0.05 to 40 mole% of units represented by a formula (I). The modified polyvinyl alcohol preferably has a viscosity average degree of polymerization of 200 to 9600, and may contains ethylene units in an amount of 0.01 to 10 mole%. The modified polyvinyl alcohol is obtained by mixing a phosphonocarboxylic acid having 1 to 7 carbon atoms in a polyvinyl alcohol solution and heating the solution in the absence of an esterification catalyst. (In the formula, n represents an integer of 0 to 6.) |
