UV-C radiation is increasingly being used for disinfection to contain the current corona virus pandemic. However, the effects of UV-C radiation on materials and coatings are often unknown.Here, UV-C test equipment supports the improvement of methods for testing coatings. © AtlasWith irradiation centered on 254 nm wavelength, the influence of disinfection measures can be simulated by UV-C radiation.

The useful service life of polymeric materials depends on their ability to resist the effects of critical weather factors responsible for the deterioration of either or both the appearance and physical properties necessary in their applications. The effects of weather result from complex interactions of the environmental elements, primarily solar radiation, heat/cold, moisture, oxygen, and pollutants, with the materials. By far, the most destructive environmental factor is the ultraviolet (UV) portion of terrestrial solar radiation absorbed by a material because it is capable of breaking some of the chemical bonds and thus initiating the degradation reactions. Because photodegradation is wavelength specific, close simulation of the spectral power distribution (SPD)of the natural source by the radiation source used for laboratory accelerated weathering is essential for simulating the natural weathering processes. The presence of short wavelengths below the solar UV cut‐on, the absence of long wavelength UV and short wavelength visible radiation, and relative intensities that do not simulate those of solar radiation can produce differences in degradation mechanisms, types of failure, and weatherability rankings of products compared with natural weathering. Sample temperatures and type and amount of moisture have a significant influence on the rate of degradation through their effects on the secondary reactions following bond breakage. Unrealistic levels of all stress factors have to be used with caution to obtain good correlation of degradation processes between accelerated and natural weathering. Because acceleration of weathering by increase in the critical stress factors differs for each material and formulation, the acceleration factor must be determined experimentally for each product. The effects of critical weather factors on polymeric materials and the various types of outdoor and laboratory‐accelerated weathering tests and their test parameters are described. The critical weather factors in natural and artificial weathering are compared and potential methodologies for predicting long‐term performance of polymeric materials are reviewed.

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.

Zur Eindämmung der aktuellen Corona-Pandemie kommt zur Desinfektion zunehmend UV-C-Strahlung zum Einsatz. Jedoch sind die Auswirkungen der Strahlung auf Materialien und Beschichtungen häufig unbekannt. Hier unterstützen UV-C-Prüfgeräte die Verbesserung der Methoden zur Testung von Beschichtungen. © Atlas Mit einer auf 254 nm Wellenlänge zentrierten Bestrahlung lässt sich der Einfluss von Desinfektionsmaßnahmen per UV-C-Strahlung simulieren.

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.