| 摘要 |
The present invention provides an industrially advantageous method for producing an unsaturated carboxylic acid-modified vinyl alcohol polymer, and a gas barrier film obtained by using the same. In summary of the present invention, the present invention is a method for producing a solution containing at least an unsaturated carboxylic acid-modified vinyl alcohol polymer characterized by reacting a vinyl alcohol polymer and an unsaturated carboxylic acid compound in the presence of an acid catalyst soluble in the reaction system or a solid acid catalyst, and a gas barrier film obtained by using the same, and an example of a representative constitution thereof is a method for producing a solution (A) containing an unsaturated carboxylic acid-modified vinyl alcohol polymer (b), the method comprising following two steps of: (1) a reaction step in which the unsaturated carboxylic acid-modified vinyl alcohol polymer (b) is formed by reacting a vinyl alcohol polymer and an unsaturated carboxylic acid compound (a) in the presence of an acid catalyst soluble in the reaction system; and (2) an ion exchange step in which at least the acid catalyst of acidic compounds is removed by an anion exchange resin.
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