Market Snapshot: Automotive exteriors 20299

There are those who won’t be satisfied with the exterior plastics market until a majority of vehicles sport plastic body panels, doors, and even hoods and trunks. While that was the vision born when plastics first entered the automotive realm, obstacles to this reality remain. Industry sources cite the investment made in automotive plants designed for painted metal body parts as one hurdle, because in general, these plants are incompatible with plastic exterior panels. Structural issues that require plastic panels to be mounted to a metal frame are another hindrance. Aside from the slower-than-anticipated growth rates, however, recent applications in this category point to a more optimistic future.

According to a recent Freedonia Group (Cleveland, OH) report, “Engineered Plastics to 2008,” the use of engineering thermoplastics in exterior applications is expected to grow by 4.8% annually through 2006, which would equate to a total of more than 1 billion lb per year (see table, right). By 2011, the figure is expected to climb to 1.3 billion lb. One factor in the continued growth of exterior plastics is the trend toward their use in light trucks, says the report.

Recent application examples abound for neat resin, thermoset BMC (bulk molding compound), and glass-reinforced materials. V. Umamaheswaran, global industry manager, automotive exterior body panels, GE Advanced Materials–Plastics, cites the recent penetration of plastics in the Smart Forfour, a larger version of the original city car. Four doors, four fenders, the front and rear center fascia, and hood are all molded of PC/PBT (GE’s Xenoy) by Peguform in Oldenburg, Germany. “Unlike the original Smart panels, however, these are all offline painted with both clear and base coats,” he says.

Additionally, the Forfour offers several roof options. One is a panoramic roof molded in PC (Makrolon, Bayer). Another involves a high-gloss, black PC copolymer film (Lexan SLX, GE) backmolded with thermoset PU via long-fiber injection by Arvin Meritor, which also molds a similar targa top for the Smart roadster.

Applications Aplenty

A bevy of current and future applications listed in SpecialChem’s Omnexus Trend Report, “Automotive Industry Likes Polymers,” underscore the predicted growth of automotive plastic exteriors:

Nanocomposites have also entered the picture, with potentially high growth rates. In addition to the 2002 nanocomposite step assist for Chevy vans, GM announced that a nanocomposite TPO material from Basell is being used in body side moldings for the 2004 Chevy Impala, its highest-production vehicle (see “Next Up for Nanocomposites,” March 2004 IMM, pp. 44-46). Even the Hummer division of GM is getting on the nano bandwagon, with the H2 SUV using 7 lb of the material per vehicle. This year, PolyOne began offering nanoblend concentrates and a new line of olefinic nanocomposites called Maxxam LST, to which two new automotive grades have been added.

Aaron Wood, BASF global key account owner, automotive, notes that another trend in the market is that of front grilles using ASA resin to replace painted and chromed ABS versions, recently seen on domestic SUVs.

“Molded-in-color ASA has weather resistance and color retention while meeting similar structural requirements and lowering the total system cost vs. painted or chromed ABS,” Wood says.

“We’re also seeing our Ultramid nylon replacing PC/ABS in door handles and being used in roof racks for greater stiffness and its ability to be used in either painted or molded-in-color applications.”

Wood contends that trends in demand are price and quality driven, with OEMs looking to drive resin part or system cost down the price curve while achieving similar performance. He also sees a need for the OEMs to differentiate. “Many are looking for metallic, molded-in-color options, with the resin industry still a few years away from being able to supply this.”