| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for purifying a coating solution by which a defective coating solution is restored in such a way that it has characteristics comparable to those of a fresh solution or the inadequate characteristics of a coating solution are improved. SOLUTION: A coating solution containing at least an electric charge transferring compound and an antioxidant is purified by removing acidic ionic impurities produced in coating by adsorption with an adsorbent selected from silica gel, alumina, magnesium silicate and activated clay. In other way, the coating solution is mixed and agitated with 8.82 times (by weight) as much pure water as the solid matter in the coating solution and the resulting solution to be separated is subjected to adsorption until the electric conductivity of the solution is reduced to 0.15-5μS/cm and the chlorine ion concentration is reduced to 0.01-0.6 ppm.
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