Patent ID: 8809490

Claim:
A method for producing a solution (D) containing an unsaturated carboxylic acid-modified vinyl alcohol polymer (b) and an unsaturated carboxylic acid compound polyvalent metal salt (c), the method comprising: (1) a reaction step for bringing about a reaction between a vinyl alcohol polymer and an unsaturated carboxylic acid compound (a) in the presence of an acid catalyst that is soluble in a reaction system, and forming the unsaturated carboxylic acid-modified vinyl alcohol polymer (b); (2) an ion exchange step for removing at least the acid catalyst using an anion exchange resin; and (3) a neutralization step for neutralizing unreacted unsaturated carboxylic acid compound (a) remaining from the reaction step (1) and ion exchange step (2) using a polyvalent metal compound, and forming the unsaturated carboxylic acid compound polyvalent metal salt (c).