The Three Layer Wet Paint System
Coating has always been the process that creates the greatest environmental burden during automobile production.
After electrodeposition coating (e-coating) process to prevent corrosion, paints that contain solvents such as toluene and xylene are applied in primer coating processes and top coat processes. The volatile organic compounds (VOC) generated during these procedures account for about 95% of total emissions for the entire production process. Moreover, each coat requires its own baking and drying process and these are responsible for roughly 60% of all CO2 emissions.
Coating processes recently adopted by many automobile manufacturers in Japan and overseas to reduce the environmental impact have only targeted VOC emissions. These have, in fact, actually boosted CO2 emissions.
Water based paints commonly used by European and Japanese manufacturers have low VOC content. However, water is difficult to vaporize, necessitating special air-conditioning and drying facilities. This pushes up energy consumption and raises CO2 emissions by 5% compared with conventional techniques. The VOC combustion method frequently employed by North American car makers reduces VOC emissions just by adding special combustion equipment to burn up the organic solvents in the coating process. However, the combustion itself raises CO2 emissions by 20%-60%. These methods are no longer appropriate for the current age, when the emphasis is on the urgent issue of preventing global warming.
Mazda has developed the unique Three Layer Wet Paint System, the first technology in the world to reduce VOC and CO2 emissions simultaneously.