METHOD OF PRODUCING PIGMENT DISPERSION RESIN FOR CATIONIC ELECTRODEPOSITION COATING MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide a method of producing a pigment dispersion resin varnish for cationic electrodeposition coating materials with the use of a compound remaining in the electrodeposition coating films which dose not volatilize into air as the solvent in rendering the pigment dispersion resin an onium without reducing the flow properties and the external appearance of electrodeposition coating films, and cationic electrodeposition coating material compositions which can be rendered harmful air pollutants(HAPs)-free or can reduce volatile organic carbon substances(VOC) (reduction in VOC). SOLUTION: The method of producing a pigment dispersion resin varnish to be used in cationic electrodeposition coating materials comprises producing a resin varnish obtained from a cationic epoxy resin composition having an amino group, a phosphonium group or a sulfonium group with the use of a solvent containing a polyalkylene oxide compound represented by the formula (wherein R is an ethylene group or a propylene group; Ph is a phenylene group; and n and m are each a number of 1 or more).