The automotive composites industry has been working to improve the processability of Sheet Molding Composite (SMC) parts for a number of years. In the past few years, the industry has made significant advances in the specific area of paintability. There are two exciting technologies now being implemented by members of the industry and automakers that improve the painted surface of plastic body panels, particularly those made with SMC:
- The development of Ultra-Violet (UV) Cured Sealer, which eliminates the "outgassing" of the composite substrate, that causes "paint pops," or a bubbled appearance, developed by BASF and first introduced by Meridian Automotive Systems on the 2003 F-150 Supercrew.
- The development of a new Tough Class A (TCA) SMC composite, that withstands handling stresses, limits air expanding out from micro-fractures (paint-pops), and results in a smoother painting surface, developed by resin supplier AOC, working with molder ThyssenKrupp Budd Co., and first used on the 2003 Lincoln Aviator.
Both of these technologies allow composite body panels to meet or exceed all automotive paint performance specifications and traditional steel defect levels.
UV Sealer and Tough Class A have dramatically improved the paintability of composites in those paint shops that have converted to one or the other process. We are seeing US automakers convert to these technologies with impressive results - upwards of a 90 percent reduction in paint defect levels. These new technologies are exciting to the composites industry because they eliminate obstacles that prevented full-scale composites use. There will be few limitations for future composites use in the automotive industry.
Composites appeal to automakers for a great variety of reasons. Their lighter weight, yet extreme toughness make them ideal for many applications and reduce the overall weight of the vehicle significantly. In addition, composites are rust-free, dent-resistant, and provide for great styling flexibility. However, composites previously offered painting challenges that were difficult for automakers. Composites were much more susceptible to minor variations in the paint shop and factors such as humidity levels, minor temperature changes, etc., affected the finished painted composite surface. These factors often limited composites applications in automobiles and trucks, to such items as truck boxes, steps, gates, etc.
The industry's new technologies allow automaker paint shops to treat composite parts similarly to steel. With the ease of paintability being addressed, composites are being seen in broader, paintable applications: on the Ford F-150 Supercrew fenders and the Lincoln Aviator front fenders, for example. We believe within the next five years, we'll continue to see composites used for more and more painted vehicle parts than ever before.
For the future the industry is working toward continued improvements, including conductive composites that will eliminate the need for additional conductive primers, more elastic sealers that will be more chip/damage resistant, and lighter weight, lower density composites that will offer greater weight/mass savings for tomorrow's vehicles.
Our biggest challenge for the immediate future is adjusting to many of the OEMs' intention of converting to a powder prime process. We, the composites industry, have begun to counter this new variable with new technologies that will process transparently through the powder prime process.
The success of these technologies is through the cooperative works of OEMs as well as the US-based Automotive Composites Alliance (ACA), which is supported by molders, and resin, tooling, primer/sealer, equipment, glass, and other suppliers in the value chain.