Related: Automotive Materials
GE Plastics Automotive (Southfield, MI) has a few new developments in composite resins:
The biggest of these is an entirely new resin called "SOLLX." This is a weatherable polymer film thermoplastic that GE Plastics has designed for use in body panels. The idea here is to transcend the technology of its XENOY resin, which is currently used for DCX's Smart car. Where the Smart panels need a clearcoat finish and have a life expectancy of only 3-5 years, a molded-in-color SOLLX panel requires no paint and should be good for up to 10 years of weather exposure (this data coming from GE Plastics' own accelerated weathering tests). Better yet, body panels made with the new resin can even be metallic colors, as opposed to Smart's solids-only palette.
The key to SOLLX is that it is possible to use a conventional in-mold decoration process, in which the film is first formed, then trimmed, and then inserted into an injection mold. The film has a draw capability of over 400% and it can be printed with graphics or designs. Finished parts are said to have an initial gloss higher than that of paint, an excellent resistance to gasoline and other chemicals, and good scratch resistance.
While the Holy Grail of composite body panels is certainly a single-step, molded in-color panel requiring no paint and no finishing, it's also certain that no one has yet developed such an elegant material. GE Plastics engineers will insist that the key word in that sentence is "yet." And until then, well, you can imagine what they'll be suggesting.
NORYL GTX has been around in body panels since the 1985 Buick Reatta. While GE Plastics admits that this initial application wasn't necessarily the greatest triumph for thermoplastics and GM's relatively quick abandonment of the program confirms this, the resin has been progressively improved over the past 15 years. It's currently used in seven production vehicles, however more may be on the way because of two new material advances. First is a 35% reduction in melt viscosity, which allows the new NORYL GTX 9700W to be used for larger parts with thinner walls. Second is an improved e-coat capability; not only is the new formulation conductive, but it can withstand 195°C temperatures for 30 minutes. This gives GE Plastics high hopes for applications in things like pickup truck boxes.
Another new formulation has nothing to do with body panels. Instead, Vibration Damping NORYL GTX is designed for underhood applications (air and electrical delivery systems) in which NVH issues are a concern. This technology allows the formulation of the resin to be altered to reduce vibration at specific temperatures and frequencies, thereby reducing sound. GE Plastics engineers claim that they can actually "tune" the material properties to achieve NVH targets for specific applications, usually at a lower cost than using metals for the components or applying secondary "noise covers."
One of GE Plastics' resins, a polyetherimide (PEI) named "ULTEM," commonly sees applications as a metallized reflector for headlamps. According to the supplier, it delivers FMVSS performance requirements for light output and beam-pattern stability, and compared to bulk molding compound allows parts to be produced with fewer processing steps at a lower overall cost. The news, however, is that GE Plastics has recently completed a validation program to show that this metallized part scrap can be recycled with no degradation of performance. Acceptable surface quality can be achieved with up to 25% regrind, according to the trials. This gives ULTEM PEI a nearly