New Mazda Basecoat Results in Lowered Emissions; a Companion to Ford’s 3-Wet Paint System

1 August 2005

Mazda Motor, in collaboration with the Nippon Paint Company, has developed a new electrodeposition basecoat (e-coat)—that substantially reduces both volatile organic compounds (VOCs) and CO₂ emissions generated as part of the vehicle painting process.

Mazda plants in Japan are some the first sites for the use of Ford’s new “3-Wet SSS” painting system that itself significantly reduces VOCs and CO₂ emissions (earlier post). The new e-coat process will further reduce painting’s environmental impact.

Mazda launched the new e-coat technology in May 2005, and will extend its use to all its main production facilities in Japan by the end of the year.

According to the company, use of the new e-coating technology will:

• Lower VOCs emissions that occur during basecoat painting at Mazda’s plants in Japan by 32 tons per year, a reduction of 50%.

• Reduces CO₂ emissions during paint manufacture by 8.8 tons per year.

• Reduce by 10% the volume of basecoat materials that are necessary compared to previously utilized painting methods.

• Improve rust protection through a more uniform thickness of paint film on the vehicle inner bodies.

In the electrodeposition painting process, vehicle bodies are immersed in a paint tank, and an electrical current passes through the steel parts, causing the paint to adhere to the metal surfaces.

Discrepancies in paint film thickness with conventional paints can result between the inside and outside body surfaces, however, because it is difficult for electrical currents to reach all interior parts and form an even paint film on interior surfaces.

The newly developed e-coating has modified characteristics that raise the paint’s electrical resistance, enabling the electrical current to reach inner surfaces more easily and reducing the amount of electricity used during painting. This provides sufficient paint thickness on inside surfaces and increases rust protection.

Optimal paint thickness is usually achieved on vehicle body outer surfaces because the electrical current flows more easily to exteriors than to internal areas. Prior to the introduction of the new e-coating system, excess paint accumulated on outer surfaces during conventional painting. With e-coating, the thickness is better regulated, allowing for a reduction in the total amount of paint necessary.