This project deals with a new inorganic UV absorber able to answer a 2nd generation requirements. Two new inorganic products have been developed and tested for this purpose. Because wood is a natural material, heterogeneous and dynamic, the weathering exposure results were rather variable, not only according to the wood species and type of resin used but also according to the type of ageing. In parallel to the weathering exposure tests, the effect of the UV absorbers onto physical, chemical and mechanical properties of finishes was investigated by implementing some analysis techniques as TMA analysis, mechanical tests, UV-visible and ESR spectra. It appears that the quality of the UV absorber to attenuate UV radiation is a fundamental element in determining photostabilisation effectiveness. In the other hand, contrarily to organic UV absorbers, the inorganic products increase the coating Tg value after weathering exposure. These phenomena can lead in particular to the crack formation.
Role of the inorganic UV absorbers on the photostabilisation of the wood-clearcoating systems.