No abstract

Outdoor accelerated weathering testing of materials using fresnel reflecting concentrators was pioneered by DSET in 1960. This type of testing is described in “Practice for Performing Accelerated Outdoor Weathering of Nonmetallic Materials Using Concentrated Natural Sunlight” (ASTM G90) and “Accelerated Exposure of Automotive Exterior Materials Using a Solar Fresnel Reflective Apparatus” (SAE J1961). The advantage of this form of accelerated weathering is that the sun's natural solar energy spectrum is used to irradiate the specimens under test. Since this is an outdoor method, variations in test conditions occur due to the natural seasonal weather differences. These seasonal variations mimic what occurs in the real world and correlation between real time weathering and outdoor accelerated weathering can be obtained for most materials with the traditional test cycles. However, advances in paint technology may require test cycles different than those specified by current test standards. The characteristics of modern, stabilized coatings indicate that they are now more resistant to the effects of both real time and accelerated weathering. Still, some failures occur in the real world that are not predicted by accelerated weathering tests. This paper will discuss the temperature and moisture control methodologies evolved over the last three years for a type of fresnel reflecting concentrator designated as “EMMAQUA®+”, an outdoor accelerated weathering test device, and the development of new test cycles for this device. This test device can simultaneously control black and white panel temperatures and provide several different moisture delivery methods. Data will be presented that will compare the results obtained with the new test cycles to the traditional cycles and to real time exposures.

Behind glass outdoor exposure testing is widely used within the automotive industry for the qualification of interior materials. This paper presents color change data for fourteen materials that underwent behind glass exposure testing, both in Arizona and south Florida. Six separate behind glass exposure methods were used for the Arizona testing and three for the Florida testing. All of the under glass exposures in this experiment are test methods that are either being used or accepted by major automotive companies. Color change test data is compared for all of the behind glass exposure methods and the resultant differences in test results and their causes are discussed.