Abstract
Cathodic Electrodeposition (CED) coating resin has one or more basic groups (ex. amine, ammonium salt, sulfonium salt, phosphonium salt, and Mannich salt group). It is dispersed in water after neutralized by acid. Therefore CED is water dispersible paint which deposits to the cathode under the application of direct current.
Epi-bis type epoxy CED coating with urethane curing system has been in use for automotive primer since later 1970's, and having a high corrosion inhibition, it has rapidly progressed in a short period, and today established a firm position in almost all the automotive production-line.
Recently, market needs higher corrosion inhibition (ex. edge corrosion inhibition), film quality (ex. appearance, weatherability), and cost down (ex. lower weight loss on heating, lower temperature curing). Along these needs, investigations on substance, curing reaction, and film making process have been progressed.
This paper discusses principally the basic design concept of CED resin and the recent technical trend, with citing literatures and patents.
