| 摘要 |
PROBLEM TO BE SOLVED: To efficiently and economically remove a metal contained in a vinylphenolic polymer with a simple apparatus by a simple operation by dissolving the vinylphenolic polymer in a solvent, providing a solution and passing the resultant solution through a specific kind of filter. SOLUTION: The vinylphenolic polymer that is a homopolymer of vinylphenols, a copolymer of the vinylphenols and other comonomers or a modified substance or a derivative thereof is dissolved in an organic solvent to provide a solution, which is then passed through (A) a filter, containing an ion exchanger and/or a chelating substance and capable of producing aζ-potential with a cationic charge regulator or (B) a filter containing (i) the ion exchanger and/or the chelating substance or a fixed bed, containing the ion exchanger and/or the chelating substance and having <=50mm thickness and (ii) a filter capable of producing theζ-potential with a cationic charge regulator to thereby remove a metal such as sodium, iron or calcium contained in the vinylphenolic polymer.
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