Cathodic Electro Deposition
Electrodeposition
Coating
Process
for Automobile
Bodies*
By Yoshiaki 0YABU,** Nobuo FURUNO,*** Yoji HIRASAWA*** and Hiroshi OMORI ****
Synopsis The earlier electrodeposition processwas mainlypursuitedfor the quality control in terms of mass production. However, the coating efficiency was picked up to be a serial problemfrom a standpoint of the harmony between natural circumstancesand human's living-life conditions and the recovery usage of the paint was earnestlysearched. This trend led to the development in various technicalfields. The second impetus on further improvementof electrodeposition paint was due to oil crisis in 1973. The new technology relating to save-energy was developed. In thepaint industries, the further improvedanti-corrosive performance was strongly demanded. This demand also involvedthe developmentof new materials for automobile bodies and even the design of bodiesstructure. In this report, the introduction of electrodeposition process into automobile industries in Japan is hystrically reviewedand the electrodeposition mechanismand the mechanism which deposited materials from the coating film are briefly explained. As the demandfor anti-corrosiveperformance is increased, the coating system in which the anodic oxidation and the dissolutionfrom the object metal can not occur, was aimed and recentlyit was rapidly accepted as the superior system. On the other hand, there is an oppositeopinionfor this trend on the basis of the metal analysis detectedin the deposited film. The characteristics of cationic electrodeposition,in particular, the superior corrosion resistance with regard to the metal dissolution in the wholeelectrodeposition processis explained. In Chapter III, throwingpower which is characteristic for electrodeposition processis described. It is referred that throwingpower is not necessarily determined by the paint performance. Even the electrodeposition coating system, the areas into which the paint liquid does not
Coating
Process
for Automobile
Bodies*
By Yoshiaki 0YABU,** Nobuo FURUNO,*** Yoji HIRASAWA*** and Hiroshi OMORI ****
Synopsis The earlier electrodeposition processwas mainlypursuitedfor the quality control in terms of mass production. However, the coating efficiency was picked up to be a serial problemfrom a standpoint of the harmony between natural circumstancesand human's living-life conditions and the recovery usage of the paint was earnestlysearched. This trend led to the development in various technicalfields. The second impetus on further improvementof electrodeposition paint was due to oil crisis in 1973. The new technology relating to save-energy was developed. In thepaint industries, the further improvedanti-corrosive performance was strongly demanded. This demand also involvedthe developmentof new materials for automobile bodies and even the design of bodiesstructure. In this report, the introduction of electrodeposition process into automobile industries in Japan is hystrically reviewedand the electrodeposition mechanismand the mechanism which deposited materials from the coating film are briefly explained. As the demandfor anti-corrosiveperformance is increased, the coating system in which the anodic oxidation and the dissolutionfrom the object metal can not occur, was aimed and recentlyit was rapidly accepted as the superior system. On the other hand, there is an oppositeopinionfor this trend on the basis of the metal analysis detectedin the deposited film. The characteristics of cationic electrodeposition,in particular, the superior corrosion resistance with regard to the metal dissolution in the wholeelectrodeposition processis explained. In Chapter III, throwingpower which is characteristic for electrodeposition processis described. It is referred that throwingpower is not necessarily determined by the paint performance. Even the electrodeposition coating system, the areas into which the paint liquid does not