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Of the 1 million Tonnes of material used for body panels on cars and trucks in 1998, approximately, 57,000 Tonnes were plastic composites. Three material types, generically labeled SMC, RIM and Thermoplastic split this volume. In each case, specific performance criteria and costs dictated the use of plastic composites. Recently, SPECTRIM* HH 390, a polyurea RIM material, has replaced SMC as the material of choice on General Motors' Silverado and Sierra Sportside vehicles. Certain performance criteria as well as overall costs paved the way for this material to be approved and utilized on such a highly visible and important platform in the light truck market. Therefore, the entry of an ELPO capable RIM material widens the choice of plastic composites for body panel materials.

In 1998, approximately 57,000 Tonnes of plastic composites were utilized as body panels on cars and trucks in North America. Three material types, generically labeled SMC, RIM and Thermoplastic are vying to carve a market niche from steel which dominates the market place with an estimated volume of 1 million Tonnes per year. Since plastic body panels have higher material costs but lower tooling costs, they are primarily utilized when build volumes are less than 200,000 vehicles per year or specific composite performance capabilities are demanded. This paper reviews the various performance parameters required of a body panel material and the relative strengths of Aluminum, RIM, SMC, Steel and Thermoplastics to meet these demands. A decision making process is utilized which allows for a comparison between the different materials. Since cost is so critical, it is left as an independent variable.

Continued development of Reinforced Reaction Injection Molding (RRIM) polyurea polymers for toughness, blister resistance and large-part processing as exterior vertical body panels has launched ELPO-compatible exterior outers into automotive assembly-line operations. This allows automotive OEM design to take advantage of the unique molding shapes for side outers and fenders while reducing weight, assembly (DFA) and time/operations costs (DFM). Polyurea RRIM body panels have been successful in meeting the demanding auto industry requirement for lightweight, damage-resistant exterior outer panels as an economical alternative to steel. Design freedom advantages, low prototype cost and tooling savings through predictive modelling have allowed the commercial use of RRIM body panels. This high-temperature-resistant polyurea RRIM composite allows on-line painting, including passing through the steel corrosion protection primer (E-coat) cure environments.

A new RRIM system produces a polyurea polymer that is capable of going through a traditional assembly process including E-coat bakes of up to 200C. In order to achieve the necessary performance characteristics, the high temperature resistant polyurea RIM polymer requires post-cure temperatures between 180C and 200C. Existing ovens are designed to post-cure materials below 160C. Also, existing ovens may not be large enough to handle pickup truck rear fenders. The existing ovens need to be refurbished or new ones built to meet the new market demand. To reduce the cost of the post-cure process, infrared (IR) radiation was tested to determine its utility for post-curing RIM parts. It was demonstrated that a infrared radiation can be used to pre-heat the RIM part in 1/10th the time of a convection oven in the laboratory. The benefit of using infrared radiation is improved dimensional stability and impact properties with acceptable flexural modulus.