The First Costing Technology In The World That Simultaneously Reduces Voc And Co2 Emissions
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Posted 20 June 2008 - 01:28 PM
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.
As its name implies, the Three Layer Wet Paint System is a one-step baking and drying coating method that applies three layers in succession—primer coat, base coat and clear coat—while still wet, without drying in between. By eliminating the drying process formerly required after applying the primer coat, CO2 emissions are reduced 15%. Moreover, a new low solvent content paint jointly developed with paint manufacturers, applied with high-precision coating equipment enables gains in coating efficiency leading to reductions of 50% in VOC emissions. In addition, by applying the primer coat and top coat in the same booth we have managed to streamline our production lines.
Until recently, it was thought that using a wet paint system would lead to problems of paints mixing between the successive layers. For this reason other companies' coating techniques require a drying stage following the intermediate coat. Mazda overcame this issue through innovations such as the newly developed interface control resin that was added to the paint. The Three Layer Wet Paint System also manifests a deep tone finish that is unique to this method.
Mazda commenced development of this technology in 1994. The initial objective was cost reduction for two-tone paints. In 1998, we expanded the horizons of the project to encompass the coating for the full car body, and added improved product value, productivity and environmental efficiency to the list of desired benefits of this technology. We established a target to develop a single solution to all these issues. The perfected Three Layer Wet Paint System was introduced after four years of experimental verification and has been adopted across all domestic Mazda production facilities.
Response to Mazda's unique Three Layer Wet Paint system technology has been sizable, and numerous domestic and overseas automobile manufacturers have come to inspect the factory. In addition, through a capital tie-up, Ford Motor Corporation is investigating the feasibility of introducing this technology to its plants worldwide. With its additional benefits in terms of reduced environmental impact, and improved product value and productivity, the Three Layer Wet Paint System may well become the international standard for the whole automotive industry.
This pioneering technological development has been awarded the Environment Minister's Prize, the METI (Ministry of Economy, Trade and Industry) Minister's Prize and various other awards. Currently, Mazda is conducting new research and development to further improve this internationally commended technology. The R&D has two major focuses. One is upgrading the process to reduce energy consumption during the initial electrodeposited anticorrosive coating process; and the other is developing "low-energy aqueous Three Layer Wet Paint System technology" for the application of water based paint to make the entire procedure even more environmentally friendly.
Mazda has developed a state-of-the-art technology that may well become the international standard for vehicle coating; the process which is currently the greatest obstacle to environmentally friendly automobile production. We will continue to pursue the ideal of a single solution to all the issues facing the coating process.
Mazdaworld Federation - Enforcer