In the demanding business of supplying coatings to the auto-manufacturing industry of the 21st century, it might be said that coatings companies must be well versed in the three ¿Es¿ ¿ economics, efficiencies and the environment.

Then too, there¿s that other big item, the one with a capital ¿T,¿ for technology.

Just ask the biggest players in the global automotive-coatings industry, and that¿s what is heard in reply: the GMs, DaimlerChryslers, Fords, BMWs and Toyotas of the world don¿t ask for much ¿ just a great-looking finish, a protective coating that resists corrosion for years, increasingly lower VOC content and other environmental benefits, and a lid on costs for materials and processing.

In response to these daunting challenges, the top three automotive OEM coatings suppliers ¿ DuPont Co., BASF and PPG Industries Inc. ¿ are pushing the envelope in the quest to provide coatings that are tougher and great-looking, and at the same time lower in VOCs, HAPs, and other environmentally unfriendly materials.

And, say the automakers to the coatings suppliers, while you¿re at it, make sure the cost remains the same for all these wonderful advances.

And advances they are getting. From PPG¿s ¿PowerPrime¿ two-in-one electrocoat primer system to BASF¿s powder-slurry clearcoat, the Big Three automotive-coatings suppliers are marching out new products and processes for every aspect of the many-faceted task of putting paint on a car body.

In an attempt to survey the state of the coatings art in the automotive segment, PCI contacted key technology executives with the Big Three coatings suppliers. DuPont¿s Dieter Engel, PPG¿s Richard Tepper and BASF¿s Joe Gdowski pointed to a host of new and innovative developments, including the following.

BASF¿s powder-slurry clearcoat, a zero-VOC product that delivers a thin-film coating. The coating has been applied to more than 300,000 Mercedes-Benz ¿A-Class¿ vehicles in Europe since making its debut about two years ago.

PPG¿s Power-Prime two-bath electrocoat system, introduced last year at a DaimlerChrysler plant in Brazil. The first bath applies a lead-free corrosion-inhibiting primer, followed by a full-body anti-chip primer-surfacer in the second bath. The system eliminates the need for a spray-applied primer-surfacer.

DuPont¿s ¿Super-High-Solids¿ developmental clearcoat, based on a proprietary oligomer chemistry. The product will offer lower emissions and stronger resistance properties, along with economic advantages due to the fact that conventional solventborne-coating application equipment will be used in application.

The coatings companies are banking on these new materials to generate solid returns in the coming years. But the manufacturers can point to a variety of other recent innovations that have helped to transform the automotive-coating process. Some of those advances are reviewed here, based on interviews with Engel, Tepper and Gdowski.

DuPont - Capitalizes On Expanded Capabilities Following Herberts Merger

Dieter Engel, vice president, Technology, for DuPont Performance Coatings, says DuPont¿s approach to automotive-coatings development centers on balancing four key demands ¿ quality, appearance, cost and environmental compliance.

In the quality and appearance department, a top priority is improved scratch and mar resistance. Seeking to meet the challenge, DuPont plans to introduce its ¿SuperSolids¿¿ clearcoat chemistry based on oligomer reactivity. In addition to lower emissions and stronger resistance properties, Engel says the technology will offer economical advantages in that existing solventborne-coating application equipment can continue to be used. The basis for the product¿s resistance properties is the generation of interpenetrating networks that result from the oligomeric chemistry.

The SuperSolids label is no exaggeration, Engel says, with the product being supplied at 85% solids content in one- or two-component versions. That compares to current systems that can go as high as 75% in two-component products. The SuperSolids clearcoat is nearing commercial introduction, and is getting serious consideration by car manufacturers, Engel says.

Another developmental project is a clearcoat that would incorporate DuPont¿s Teflon® fluoropolymer to resist dirt ¿ a sort of ¿self-cleaning¿ finish. DuPont currently produces refinish clear coatings incorporating Teflon.

In the waterborne area, Engel noted that DuPont benefits from Herberts¿ record as a pioneer of waterborne-coatings advances in Europe, where the company¿s credits include a major role in the development of a total waterborne paint system applied at a GM/Opel assembly plant in Eisenach, Germany. The system includes an electrocoat supplied by another coatings company, followed by waterborne primer, basecoat and clearcoat products formerly provided by Herberts, now DuPont.

A major priority at Herberts prior to the merger, and at DuPont as well, is an approach that focuses on reduction in total applied costs. ¿Developments in application equipment are just as important as chemistry developments,¿ Engel says. This big-picture approach is the driving force behind R&D efforts carried out at application centers in North America and Europe.

In the powder area, DuPont is continuing to carry out powder-clearcoat application trials at BMW¿s assembly plant in Dingolfing, Germany, where the automaker began using powder clearcoats about two years ago. In the automotive segment, Engel says economics are more of a driving force than technology in determining whether powder use expands significantly in the automotive segment.

¿Powder clearcoats, from a technology point of view, are a ready-to-use technology,¿ he says. ¿The only question is how much a car manufacturer is willing to put forward to make it work.¿ In North America in particular, he says, the automakers are leery of undertaking major plant revisions without first ensuring that the product and processes are in place to deliver the type of finish quality demanded by the marketplace. Another factor, he says, is the preference of American automakers for single-source coatings suppliers. Thus, a technology such as DuPont¿s SuperSolids clearcoat might rate better odds of seeing widespread use than powder, at least in the near term, due to combined quality and environmental advantages, and relatively modest investment and process costs.

In Europe, on the other hand, auto manufacturers are more inclined to carry out development refinements on the assembly line, he says, citing BMW¿s continuing efforts to perfect powder clearcoat application in Dingolfing.

In the waterborne area, Engel says DuPont is preparing to launch waterborne-primer application at a major auto-manufacturing plant in the United States, a move that would put the plant in step with European carmakers. There, he says, waterborne primers are viewed as ¿standard technology,¿ while solventborne and powder coatings are the dominant technologies used in North America.

A focus of R&D for automotive plastics, he says, is the challenge of achieving perfect color matching in the cured finish on plastic and accompanying metallic substrates, particularly on exterior body areas. The key is obtaining an exact match even though the plastic coating is cured at a much lower bake temperature. Here, improved chemistry will hold the key, he says.

Another objective is development of technologies that reduce the number of coatings layers, such as combined e-coat/primer, fewer application layers for primers and basecoats, or multiple ¿wet on wet¿ technology to reduce bake requirements. Application of additional layers to boost performance and appearance could be reserved for high-end vehicles.

Pondering longer-term possibilities, Engel says DuPont is expecting to draw on the combined capabilities of its Performance Coatings and other business units to introduce new products and processes. As an example, he mentions DuPont¿s presence in the market for ink-jet ink products as a potential source of scientific advances in the dispersion and stabilization of coatings pigments in applications such as automotive finishes.

Another potential source of technological breakthrough is DuPont¿s life-sciences expertise, which could lead to technology transfer in the area of renewable, crop-based raw materials for coatings and other products, he says.

An auto body finished with the Enviracryl powder clearcoat is inspected at BMW's plant in Dingolfing, Germany, where more than 300,000 cars have been finished with the PPG coating. The first commercially successful automotive powder clear coat is used on BMW 3-, 5- and 7-series cars.

PPG - Emphasizes Systems Approach To Various Components

Tepper, PPG¿s global director of Technology, Automotive Coatings, says the company is emphasizing a unified automotive coatings system approach, where the various components are viewed as part of an overall unit, and are developed with that in mind. In the automotive industry, that approach helps meet demands for cost, performance and processing improvements, he says. Also a high priority is the development of ¿global¿ products that can be used by auto manufacturers worldwide, with some tweaking to account for the different application and performance demands of various geographic regions.

Major recent developments for PPG include the following.

  • Organic pretreatment products designed to reduce or eliminate the use of nickel, chrome and nitrite. ¿The goal is to replace inorganics with organics,¿ Tepper says. The products also are designed to reduce the number of steps involved in pretreatment and to be applied to various types of substrates, including steel, aluminum, and plastic. Here, PPG is able to draw on its in-house polymer-chemistry capabilities. The pretreatment products are in the process of being commercialized.
  • A lead-free electrodeposition primer, Enviro-Prime 2000, an epoxy crosslinked urethane system that the company says is being used at several auto plants. The product takes VOC content even lower than an existing e-coat primer, and cures at lower temperatures, the company says.
  • The Power-Prime two-bath e-coat system, introduced last year at a DaimlerChrysler plant in Brazil. The system involves the application of an e-coat primer, followed by electrodeposition of a primer-surfacer coating, with only a partial, or flash, bake required between the separate baths. PPG says the primer-surfacer product is the first e-coat of its type.

¿It¿s being received very well,¿ Tepper says of early results at the DaimlerChrysler plant, which manufactures Dodge Dakota pickup trucks. A key challenge, he says, was the development of a product and process that provided the conductivity in the initial primer coat that results in electrostatic deposition of the primer-surfacer. The system offers a near-zero-VOC alternative to conventional spray-applied primer-surfacers, and is said to provide a more uniform coating. The system also is designed for application on exterior sections of the auto body that are subject to chip.

The plant in Brazil was chosen for the initial commercial application, he says, in part because the site¿s design allowed the two-bath e-coat process to be integrated without major difficulties. Also, the facility is not one of DaimlerChrysler¿s highest-volume operations, and thus posed less of a risk of production disruption during trials.

This system, in use for the past year at DaimlerChrysler's plant at Campo Largo, Brazil, was a finalist for a PACE Award and received an R&D 100 Award from R&D Magazine last September. Negatively charge vehicle bodies are immersed in positively charge coatings baths. The first applies a corrosion-inhibiting primer to the entire body. The second applies the world¿s first full-body anti-chip primer-surfacer on the exterior; it replaces conventional spray-applied primer-surfacers.
PPG views the technology as a long-term investment, because the ideal candidates for installation of the application system are new plants, or existing plants where major retooling is carried out. ¿It¿s not a drop-in technology,¿ Tepper says. The technology also is best suited for situations where frequent color changes are not required. But the company is quite bullish on the prospects.

¿The results are phenomenal. The quality of the job is outstanding ¿ as good or better than anything I¿ve seen,¿ Tepper says.

Besides excellent resistance properties, he says the process results in reduced sanding requirements and higher gloss levels. On the heels of the installation in Brazil, he says he anticipates new applications going online elsewhere in the near future. ¿We would expect to have one or perhaps two new sites this year.¿

Also in the works is a product Tepper calls a ¿functional primer¿ ¿ a coating that serves double-duty as both a degradation-resistant primer and a ¿modified basecoat¿ by providing a finish on interior sections of autos that may not receive complete coverage by the spray-applied basecoat that follows. The spray-applied system could serve as a replacement for a primer-surfacer coating, and is viewed as a likely candidate for use on lower-priced vehicles, for areas such as doors and door-jamb areas.

Other developments include the following.

  • New versions of the company¿s ¿Envirobase¿ waterborne acrylic basecoats. Here, Tepper says PPG is touting a ¿global¿ product ¿ one that can be used by a customer at any plant, from Australia to Canada. ¿The product is designed for a wider workability window,¿ he says, with formulations easily tailored to highly varied temperature and humidity conditions. The product also addresses the immense variety of regulatory requirements encountered in the different markets worldwide, thanks to ¿mass customization¿ capabilities, he says. The product is expected to further the cause of conversion from solventborne to waterborne basecoat application.
  • Development of a new clearcoat tentatively given the name ¿CeramiClear.¿ Few specifics are being provided about what Tepper says will prove to be a ¿breakthrough¿ rather than an ¿incremental¿ technological leap forward. The product, which will be introduced as a solventborne coating, is billed as being highly resistant to marring and UV degradation. The company says the product, which is expected to become commercial this year, is based on ¿a unique chemistry,¿ but no other details about the product¿s composition are being revealed.

The powder clearcoat being applied to a BMW.
  • Further development of the company¿s ¿Enviracryl¿ automotive powder clearcoat, aimed at expanding use of the product beyond its current status as the world¿s first commercial application of a powder clearcoat on auto bodies. Application of the product began more than two years ago at BMW¿s assembly plant in Dingolfing, Germany.

In addition to appearance and application refinements, PPG said cost reductions are a top priority in development work associated with the powder clearcoat. The company said it is targeting a cost structure that would push powder-clearcoat application costs below that of high-performance two-component polyurethane systems.

In terms of finish performance, Tepper said the powder product compares favorably with a 2K polyurethane system, with further refinements needed in certain areas. One area of focus is appearance over white colors, where a yellowing tendency occurs. Technical experts have traced the problem to a phenomenon that develops at the basecoat-clearcoat interface, and a solution is likely to be found by changing the basecoat chemistry, he says.

Another issue that continues to get attention is a difference in appearance that results when a powder-coated vehicle finish is touched up in the assembly plant with a conventional polyurethane. Ironically, when there is a variation, it is usually caused by the superior appearance of the powder clearcoat, Tepper says. But he views the color-difference issue as a minor obstacle that will soon be resolved.

In North America, Tepper says he expects some sort of new, zero-VOC clearcoat technology to emerge in the auto-manufacturing landscape, whether the coating is powder or liquid. Resistance to such new technologies on the part of American automakers will lessen as existing application materials and methods are refined, he predicts.

¿The greatest sales technique to move powder coatings forward is to examine our results in Germany,¿ he says. He points out that the powder clearcoat is being used on high-end BMWs, in a partnership involving a coatings supplier and one of the most demanding automotive customers anywhere. ¿I don¿t consider that to be an oddity,¿ Tepper says of BMW¿s choice of clearcoat.

Taking a big-picture view, Tepper says PPG and other major coatings suppliers are moving toward a solutions-based approach to their automotive customers, offering expertise on the entire universe of coating/finishing considerations. This ¿systems and science¿ approach spans a myriad of material and application issues, from types of pretreatments, to designing a finishing-process line, to reducing environmental impacts from one end of the process to the other.

¿We¿re not selling gallons of paint. We¿re selling solutions in materials and processing,¿ Tepper says. The cost of the material may actually be higher on a per-unit basis, but processing or performance benefits provide an overall addition of value, he said.

BASF's powder slurry clearcoat has been introduced in the "A-Class" production lines at DaimlerChrysler Rastatt.

BASF - Zeroes In On Environmental, Economic Gains

Joe Gdowski, global technical director, BASF Corp. Automotive OEM Coatings Group, with an assist from David Elliott, manager of Communications, said the major theme for BASF¿s automotive-coatings R&D efforts has been given the label ¿ECO2¿ ¿ representing ecology and economy. Thus, the emphasis is on technologies designed to reduce environmental impact and/or provide economies for users. As a result, the company has invested in the development of zero- or near-zero-VOC products and materials that offer economic gains in the applications process.

At the top of BASF¿s list of new technologies is a powder slurry clearcoat for auto bodies, a zero-VOC product that offers appearance and process advantages. Besides delivering a thin-film coating in the 2-mil range ¿ better than the results with powders at this time ¿ the product can be applied with conventional application equipment. BASF reports positive results from its experience in application to Mercedes-Benz vehicles in Europe, and the product has generated interest among other carmakers. The product is expected to undergo trials at the Low Emissions Paint Consortium (LEPC) test facility in Michigan, a joint R&D project being carried out by GM, Ford and DaimlerChrysler, in conjunction with coatings suppliers

The clearcoat is produced by dispersing a powder coating in water to produce a slurry that is then electrostatically spray applied. The coating represents the final step in a ¿wet-on-wet-on-wet¿ process ¿ applications of a primer and basecoat are followed by flash-off, and the bake follows the clearcoat application. Both process efficiencies and environmental benefits result, the company says.

Also in the clearcoat category, BASF says it is enjoying considerable commercial success with its Ureclear® clearcoat, a one-component carbamate system said to provide the excellent resistance properties of two-component polyurethane systems. The product is an acrylic with carbamate functionality, which provides urethane properties without the use of an isocyanate, the company says.

The Ureclear system delivers on the ¿economics¿ side of the ECO2 concept, providing cost and handling benefits for coatings users. The product is being applied at nine auto plants in North America, including assembly plants operated by Ford, GM, and Nissan, BASF says. The company last year received the Henry Ford Technology Award for Manufacturing ¿ presented by Ford¿s namesake company ¿ for the development and commercial implementation of the coating.

Also getting considerable attention by BASF are radiation-cure coatings for automotive applications, where the technology is viewed as offering the potential for both environmental and economic benefits. The company last year announced the launch of a campaign to develop UV-cure coatings for automotive bumpers and components as alternatives to conventional solventborne systems. Some UV-cure coatings are in use in Europe, and the company is planning to introduce those technologies to the North American market.

Among the candidates for use in the automotive segment is a sealer for plastic sheet molding compound (SMC), a material that is used extensively in vehicle exteriors. The company says a key attribute of the UV-cure product is its ability to eliminate blistering, a common defect in conventional coatings applied to the SMC substrate. Another UV-cure coating expected to enter the market is a clearcoat for flexible plastic components such as bumpers. The UV-cure coatings are described as very high-solids ¿ in excess of 90%.

In addition to developing new coatings technologies for the automotive market, BASF is looking to expand its presence in the powder-coatings segment in North America with a new powder-manufacturing facility under construction at the company¿s Morganton, NC, site. The plant, scheduled to begin operation in midyear, will supply products for the automotive-component market and is being looked to as a source of growth opportunity in the appliance, metal office furniture, and protective pipe coatings markets.