Method of controlling the composition of a bath suitable for electrophoretic coating and use of an organic chelate complex former in an electrocoating bath

摘要

A method of controlling the composition of the bath, which contains a synthetic resin rendered ionically soluble in an aqueous medium, by ultrafiltration of at least a part of the bath is characterised in that an organic chelate complex former which reacts to form a heavy metal chelate complex capable of ultrafiltration is added to the bath before carrying out the ultrafiltration to improve the ultrafiltration capability of heavy metal ions.