Analysis on the Major Environmental Factors Affecting the Weather Resistance of Polyester Coating

Abstract

Three types of polyester coatings were selected and subjected to 2-year natural exposure in Qionghai, Shenyang and Turpan. After natural weathering, the signs of discoloration and losing light were found on all the three polyester coatings. The polyester coatings under atmospheric environment with higher corrosion concentration were more impacted at the initial stage by such factors as pollutant, rain-wash and temperature, i.e. with large color aberration and aging rate, while at the late stage, the color aberration and aging rate either dropped or slowed down. Similar to the environmental factors affecting color aberration, the variation in glossiness indicated that high temperature or high irradiance simply did not keep glossiness degrading greatly in long term; instead, the combined environmental factors such as high temperature and humidity, high irradiance and high salt were mutually promoted and synthetically acted to accelerate the aging of coating. By comparing among the test results from the three sites, Qionghai has stronger ultraviolet radiation, higher salt concentration in the atmosphere, and higher temperature and humidity throughout the year. Therefore the weather in Qionghai is harsh enough to produce good accelerating effect, which enables rapid establishment of the methodology system for evaluating the environment adaptability of polyester coating.