How Cars Get Their COLORS

The North American International Auto Show held in Detroit this past January was an especially exciting one, with more than 750 vehicles on display, including 61 new introductions. Body styles ranged from retro to futuristic, while colors ran the gamut from traditional solid shades to exotic hues with highly attractive special effects, such as color travel. In fact, the new paint finishes were among the special delights for the record-setting 810,000 attendees. As the visitors roamed through the exhibits examining the vehicles, many noted the pleasing array of colors, and a frequently asked question was, “How were they developed?” The answer to that is an interesting story that begins years before the actual production of the vehicles. Let’s follow the case history of one such new color, GM’s “Arrival Blue,” which is based on a special blue-colored aluminum pigment, FIREFLAKE D-551BL, and is currently available for 2003 cars and trucks.

New Effect Pigments

This new color makes use of the blue-colored aluminum pigment, FIREFLAKE D-551BL. It is one color in a new class of pigments, developed during the last decade by Showa Aluminum Powder of Japan, and introduced to the major automotive paint suppliers in the United States by U.S. Aluminum Inc. These unique FIREFLAKE pigments are produced by means of a patented process in which the colorant is bonded to the aluminum particle surface to produce a single pigment flake. In the final stage of the process, the colorant is sealed to the FIREFLAKE colored aluminum flake with a crosslinked acrylic polymer (see sidebar).

"Effect pigments are becoming increasingly popular in many different markets,” says Marilyn White, executive director of The Mix, a color forecasting company. “Consumers want colors that are novel, bright and reflect their independence.” She noted that two automotive OEMs have highly chromatic bright blues based on FIREFLAKE in their 2003 color palettes.

Colored Aluminum Production

Because each colored aluminum flake is a single unit, rheological advantages allow a broader range of colors to be formulated. Combining these colored aluminum flakes with other pigments produces coatings that exhibit color travel, or flop, when viewed from various angles. For example, mixing a blue-colored aluminum with a transparent red pigment will yield a finish that appears purple when viewed head-on, but shifts to a red-shade blue when seen from a side perspective. While paint made with conventional aluminum pigments can reflect different color intensities when seen from different directions (dark blue to medium blue, for example), colored aluminum pigments provide the added aesthetic benefit of producing a distinct change in hue. Another advantage of colored aluminums is that they have excellent hiding power -- much greater than that seen with mica-based pearlescent pigments. As a result, thinner films are possible. This is a key benefit in the automotive industry, where today’s waterborne formulations are limited in terms of film thickness.

The problem of mutual interference -- a dulling effect that occurs when particles block each other’s reflectivity -- is eliminated because the pigment and colorant are contained in a single flake. Moreover, the colored aluminum flakes tend to align themselves horizontally in the film, with each flake acting as a tiny mirror, enhancing the depth and sparkle of the finished coatings. This high reflectivity and richness, combined with colored aluminum’s other benefits, has created a great deal of excitement among industry insiders, who see an almost infinite potential for colored aluminum.

Al Ball, independent consultant on automotive colors, thinks that in the near future FIREFLAKE pigments can capture 20% of the automotive OEM for metallic blue paint currently made from aluminum and mica pigments. “The reason this is possible is the extra chromaticity and hiding power that’s achieved,” he says. “It will be widely used by the automotive industry because the price for the ‘effect’ is reasonable.”

Trends Dictate Palette Choices

The color of a car is an important selling feature, so it is no surprise that automakers fret over the appearance of their multilayer coatings. To create more dynamic-looking automobiles, manufacturers are using ever-increasing amounts of special-effect pigments. Technology-based colors, such as those that create a liquid-metal effect or sparkle, and nature-based colors, such as calming neutrals, cool blues and warm browns, are driving automotive color trends worldwide. Since it typically takes at least several years to approve an effect pigment, and automotive color palettes are developed at least three to four years before a car is marketed, anticipation of future color trends is imperative. Effect pigment manufacturers must forecast color trends accurately in order to develop and successfully introduce products that meet the needs of both automotive manufacturers and consumers.

Accordingly, the automotive group within each major paint manufacturer strives to develop accurate long-range color plans by analyzing the development objectives of the various automobile companies. This team also observes color trends from a variety of perspectives, including consumer preferences, fashion, interior design trends, other industries, technological innovations, and even current events.

Likewise, automotive designers understand that a keen awareness of future trends in color is essential to developing a successful palette for their car and truck lines. The colors they select must not only give their vehicles identity and distinction on the road, but must also appeal to the broadest number of car buyers. In collaboration with paint company designers, they predict consumer preferences by studying a wide range of design viewpoints, and also rely on information gathered from surveys and focus groups.

Figure A / The surface of the flake is specially prepared to maximize pigment adsorption.

How Colors Are Selected

Paint companies hold annual color shows at which all of the new colors are presented to the automotive designers and stylists. Selections are made for as many as four years into the future. GM selected “Arrival Blue” because it fell within the color position that the company had wanted to enter.

Silver, white and black were the most popular North American vehicle colors for the 2001 model year, according to annual popularity surveys. Future tones are expected to be more sophisticated and chromatic due to new effect pigments, which add sparkle and provide crisper hues. It is predicted that buyers will demand a wider range of blues that are more colorful and present an increased metallic aspect and greater sparkle.

It has long been known that certain colors can create emotional and intellectual impressions. For instance, blue imparts a feeling of security and trust, and also is perceived as representing stability. Whereas silver is the most favorite automobile color in North America today, many experts believe that an increasing demand for shades of blue will arise, resulting in an increased assortment within this family. It is also believed that, as interest in these new shades increases, demand for the green hues will decline. Many factors contribute to this change of taste, but a partial basis for this forecast is the feelings of uncertainty Americans have about the economy and current events. According to Marilyn White, the demand for green tones has declined by about 60%. “Bright blues seem to be increasing in popularity at the expense of the green shades,” she says, adding, “The FIREFLAKE Blue has popular appeal because it is highly chromatic.”

With this information in mind, paint company stylists have prepared a variety of blue colors, one of which is a deep rich tone. This particular color space had been difficult to achieve, but the inclusion of FIREFLAKE D-551BL opened the door. “Within 6-9 months the color stylists with the paint companies will be able to assess this color’s popularity and how well it has come into this niche,” White says. In the longer term, Al Ball envisions increased combinations, such as blue and green and yellow, being evaluated for their effects. “I believe we also will see FIREFLAKE formulated with combinations of organics to obtain contrasting or complementary color shades,” he added.

Figure B / The colorant pigment is added, and is adsorbed onto the specially treated aluminum flake.

Testing New Pigments

Color development is not limited to identifying future trends, however. New possibilities in hues and visual effects are supported with the research and technology that enable concepts to become realities. Once paint companies identify the potential value of newly developed pigments, they immediately put them through a series of stringent tests. For example, circulation stability and outdoor weather durability are evaluated. If the pigments pass such tests, they are then formulated into a variety of colors to determine if they are truly valuable new styling tools.

Each paint company serving the OEM market has a sizeable evaluation team, which screens new pigments to ensure they are not only light-stable, but accurately colored and consistent. But this is only the first step of the development process. Full-size production batches of paint are made, and then tested for ease of production, sprayability, uniformity and so forth. Another full-scale trial comes next at an assembly plant where a complete vehicle body is painted under actual production conditions.

Plant Testing of New Paints

Assuming all goes well to this point, color standards are prepared and sent to all parts suppliers and secondary paint companies. These absolute standard panels must be precisely matched for application to such hang-on parts as rear view mirrors, spoilers, flexible bumpers, door handles and certain interior components. The final testing comes about six months or so before full model year production is to begin. As many as 100 vehicles are “pulled ahead,” painted with the new color, assembled and closely inspected. These vehicles may be used for internal company purposes, while some are sold or placed at dealerships to get preliminary buyer feedback.

Figure C and Figure D / The flake undergoes an encapsulation process that chemically bonds the colorant to the aluminum by means of a high-molecular-weight synthetic polymer.

Full Production

Finally, in the summer of 2002, the full model year production of “Arrival Blue” cars and trucks began at several GM assembly plants across North America. In a sense, the most important stage in the development of this new color actually commenced at this point -- acceptance by the general buying public. This is the final vote that determines if all of the above steps have led to success. Many years of development work by the pigment producer, the paint maker and the auto manufacturer hang in the balance. Were proper decisions made along the line? You be the judge.

Conclusion

Aluminum pigments occupy an important position in the coatings industry, especially in the automotive segment. That position could become even more prominent with today’s new colored aluminum flake pigments. Along with all the benefits of conventional aluminum, these new materials have the potential to expand the range of colors available to the stylist, while imparting striking visual effects like color flop, and increased brightness and depth.

The market potential for FIREFLAKE pigments reaches out beyond the automotive industry. Printing ink, packaging materials, architectural paint, textiles, cosmetics -- any industry that values novel visual effects can benefit from this new pigment technology.

For more information, contact Bill Cwieka, vice president, Sales, U.S. Aluminum Inc., phone 800/544.0186 or fax 908/782.3489.