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Automotive Coatings...A Brief HistoryPosted 5/16/2001
The automotive coatings industry began with the mass production of automobiles in the early 1900s. By 1903, every major producer of vehicles was coating its products with typically the same finish: India enamels. India enamels were, in effect, paints left over from carriages and stagecoaches. The term India referred to both the pigment and vehicle resin package and not to the country, as is so often assumed. All of these early finishes were brushed on at the factory. Colors were limited. Blacks, dark green and browns dominated the palette and generally the final appearance was fair to good by today's standard. One distinct advantage of these coatings was the ease of repair. India enamels were easy to obtain and relatively easy to apply by the car owner via a paint brush. The problem with India finishes was that they faded rather badly in the sunshine. India enamel's drawbacks led to the invention, about 1923, of the nitrocellulose-based enamels. Compared to India enamel coatings, nitrocellulose enamels were much more durable and colorfast. They could be applied either by brush or by spray and they dried very quickly as compared to the India product, thus speeding up auto production. Nitrocellulose enamels also offered, for the first time, a wider range of color choices to the market. It was not until the mid-'30s that the next major innovation in paint finishes was developed: alkyd enamel. This product signaled the beginning of what might be called “the era of modern finishes.” The alkyd resin base represented a significant improvement in automotive finishes, especially in relation to gloss levels. If it can be said that “shiny sells,” then alkyds were the first finishes with outstanding gloss characteristics designed to catch car buyer's eyes and influence buying decisions. Alkyds as a whole proved to be more durable and faster drying than nitrocellulose enamels, and exhibited both excellent final gloss and gloss retention. With the advent of World War II, the pace of automotive finishes development slowed to a crawl throughout the late '30s and early '40s. It wasn't until after the war that the next great technology leap happened: acrylic lacquer. Acrylic lacquer, while not markedly better in terms of performance qualities over alkyd enamels, did possess one outstanding trait: it was incredibly fast drying as compared to enamels of the time. Automobile companies such as General Motors immediately saw the production time savings as a real plus in the race to build the cars that were needed as automotive consumers returned in droves from the war. The acrylic resin base was slightly better, performance-wise, over its alkyd predecessor. The acrylic or plastic-based resin was tough and did stand up well to the elements. It could be buffed and detailed easily and in the aftermarket, the product was a boon to quick cycle times in the body shop repair business. Because of its quick drying characteristics, lacquer was also easier to handle and spray. The only real production problem with lacquer was the need to buff it to get acceptable gloss. Color formulations were vast and this technology led to a real expansion of the automotive color palette. By the early '60s, acrylic enamel was introduced. The acrylic resin system was found to work equally well in enamel and, unlike lacquers, this product did not have to be buffed and its final gloss was outstanding. Workability and dry times were competitive with lacquers and the durability numbers were competitive. Color choices also were competitive with lacquers and these finishes exhibited much better UV resistance. Although these factors were significant, the real value of this technology was that its next logical product line extension was the addition of catalysts or cross linkers to the product lines. Polyisocyanate in nature, these catalysts dramatically magnified and improved acrylic enamel's performance qualities. In fact, up to 50 percent improvement in such characteristics as gloss, hardness, durability, workability and dry times turned a rather normal product into the first “leap frog” product line in both OEM and aftermarket environments. While we have concentrated on topcoat technologies in this brief history, we would be remiss if we did not consider one primer system because of its dramatic effect on the market: cationic electrodeposition. Throughout the '50s and '60s, corrosion was the major cause of automobile obsolescence. Rust, especially in certain areas of the country, at one time could shorten an automobile's life span to two to three years. The problem was severe and auto consumers were literally screaming for a solution. The industry responded to consumers' needs. For example, PPG Industries responded with a cationic electrodeposition primer in 1976, eliminating corrosion as a major cause of automotive failure. The system involves electrically applying primer in a large bath where the vehicle is charged one way and the primer the opposite. The bond is strong, practically rustproof and long lasting - not to mention economical. It is still in wide use. Today, 99 percent of all vehicles manufactured use some type of electrocoat process. From the early '60s to the '80s, acrylic lacquers and enamels dominated the marketplace. By the mid-'80s, however, consumers' dislike of “the look” of the then current finishes led major paint companies to develop the next major technology change: basecoat/ clearcoat. There is no doubt that the German automakers influenced this change with their color-plus-clear combinations on such premium vehicles as Mercedes Benz. The Americans, fearing lost sales due to duller finishes, rushed to introduce base/clear. The technology itself was a one-stage acrylic flat basecoat followed immediately by a high gloss urethane catalyzed clearcoat. Whether the carrier reducer was solvent or water, base/clear exploded into the marketplace by the early 1990s. Basecoat/clearcoat was the ultimate in finishes - featuring excellent durability to corrosion and stone chips, very high gloss and extremely friendly handling traits for applicators. In one form or another, base/clear remains the mainstay of finishes even today. The future looks brighter still with advances in waterborne technology and powder coating products. Waterborne basecoat is becoming increasingly popular in Europe, even in nonregulated regions. Powder clearcoats and powder anti-chip finishes are already being applied by OEMs and have the potential to take the market by storm, mainly because of their low volatile organic compound content and their recycleability. UV catalyzed finishes could also become a substitute for the more volatile isocyanate cross linkers that are still very much in the marketplace. New advances in sound deadening coatings and electrodeposition primers combined with primer-surfacers also will have a positive effect on the market. The next five to 10 years will again be a time of immense change in this very innovative industry.
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