Automobiles have long required four coats of paint: e-coat, primer, color coat, and clear coat. DuPont's EcoConcept paint and process enabled Volkswagen de Mexico to eliminate the need for the primer coat, so Volkswagen can now paint a car with three coats, not four. This eliminated one spray booth and the associated oven, which yielded significant savings for Volkswagen, increased profit for DuPont, and decreased volatile emissions from the paint process. EcoConcept is a water-based paint system.
After long development, DuPont formulated a color coat that adheres directly to the e-coat as it would to a primer, but without it. To prevent separation, they also developed a basecoat additive that greatly attenuates UV transmission through the clear coat and base coat. However, to prevent premature separation from the e-coat, the color coat thickness must be carefully controlled. This paint thickness depends on the color. DuPont established these thicknesses to include a safety factor allowing for variability in the paint application process.
In Mexico, DuPont developed a laser-based in-line process to measure the "wet" paint thickness on each body, with feedback to adjust the system on subsequent bodies if necessary. This was the final step in making EcoConcept Paint operational.
The system is in full production in one of the VW Jetta paint shops in the VW Puebla, Mexico, complex, and in the VW paint shop in Pamplona, Spain. It will soon start up in VW South Africa. At present, the plant level of defects from other causes and overall paint rework are about the same as with the old paint system, but the new system has more diagnostics for improvement of paint process quality. The new paint is repairable with no new problems, in dealer body shops.