Formulating Electrodeposition Resins

Electrolyte contamination is a serious problem in an electrodeposition tank and quantities of the order of 50 ppm will give rise to fill defects, as well as reducing the rupture voltage and the coulombic efficiency. This is a matter which is relevant to running the tanks rather than formulating either resins or paints. 

After rinsing and dry-off, the primer is applied. In most modern plants this means electrodeposition of the primer (Section 14.1). The most widely used primers are cathodic. The body shell is made the cathode and current flows between it and inert anodes in the electropaint bath. The paint is formulated so that the resin is basic and, when neutralised with an acid such as lactic acid, becomes positively charged. The most widely used resins are epoxy-amine adducts ... 

The paint formulator has additional latitude in the choice of resins because dispersed macroions can be used as emulsifying agents for a variety of resins. These, as well as many pigments, will electrodeposit together with the macroions. 

The formulation of acrylic resins for electrodeposition is not very different from formulating them for any other use. There are so many acrylic monomers available that almost any property desired can be incorporated, so it is just a matter of selecting the right monomers, initiators and solvent. 

---