Photodegradation of mulitlayer automotive coatings tracked in detail

Abstract
In multilayer automotive coating systems, it is often the e-coat layer which degrades under weathering, leading to coating failure and corrosion. Photo-oxidation index (POI) measurements on multi-coat systems showed that the POI of the e-coat increases during artificial weathering. This degradation process is influenced by both UV and thermocatalytic effects, so dark coatings increase e-coat degradation.