Лако-красочные материалы — производство

While the most meaningful exposure testing of polymers is done under actual exposure to sunlight, accelerated aging devices are used routinely to provide predictive and reprodu­cible data in a reasonable amount of time [10,11]. The UV output of several commercial weathering devices is shown in Fig. 7. While many of these instruments are equipped to regulate temperature, humidity, and water spray, the most important environmental para­meter to duplicate is the spectral distribution of sunlight. For instance, a carbon-arc lamp emits a high intensity of low-wavelength, high-energy radiation, which may initiate photo­reactions not seen in actual use. The xenon-arc lamp more closely matches the spectral distribution of sunlight and has been found to correlate well with outdoor weathering. Other exposure devices, including the Q-U-V weathering tester [11], have shown good correlation with outdoor exposure when used with a UV-340 bulb.