| 摘要 |
Acid is removed from cathodic electrocoating baths in which electroconductive substrates are being coated with cationic resins present in the form of aqueous dispersions, at least a portion of the coating bath being subjected to an ultrafiltration where the ultrafiltration membrane retains the cationic resin to form an ultrafiltrate which contains water, solvent, low molecular weight substances and ions and is at least partly recycled into the coating bath, by subjecting at least a portion of the ultrafiltrate to a specific electrodialysis treatment before returning it into the electrocoating bath.
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