Comparison between natural and artificial weathering of e-coated galvanized steel panels

The natural weathering of electrophoretic coatings exposed to continental weather in Trento (Italy) for about one year was considered. The environmental factors (such as wet time, temperature, and r.h.) affecting the properties of the organic coatings were monitored and investigated to ensure a consistent comparison between the laboratory results and the real weathering of the materials. The properties of the coatings were evaluated also after different laboratory tests using mainly EIS. The effects of the accelerated ageing were compared to the results of the outdoor exposure to get some insight into the understanding of the correlation between indoor and outdoor exposure.

► Accelerated laboratory tests and outdoor exposure of e-coating are studied.
► The water uptake of the polymeric matrix affects the outdoor durability of the paint.
► Salt spray test and immersion test are not able to simulate the outdoor exposure.
► Cyclic UV lamps/r.h. 100% exposure simulates quite well the outdoor exposure.