The Effect of Basecoat Pigmentation on Chemical Structure and Surface Topology of an Automotive Basecoat/Clearcoat System during Weathering

This study aims to elucidate the effect of basecoat pigmentation on chemical structure and surface topology of an automotive basecoat/clearcoat (BC/CC) system during accelerated weathering exposure. Two kinds of basecoat pigmentation (silver and black) were chosen by this assumption that other basecoats would behave somewhere between the silver and the black pigmentation. The chemical and topological structures of the coatings were investigated after various weathering exposure times (0, 150, 300, 450, 600 hours). The variations in chemical structure of bulk and surface of clearcoat were analyzed by FTIR and ATR spectroscopy, respectively. Also, to follow changes of polarity and morphology of clearcoat's surface, surface energy measurements and AFM were utilized. It was found that black basecoat induced more post-curing reactions in attached clearcoat at initial weathering times, while silver basecoat induced higher photo degradations during whole times of weathering. These were related to absorption and reflection of black and silver basecoats when they were exposed to light. Also, it was observed that surface energies of a clearcoat having silver basecoat increases more than that of having black basecoat.

کلیدواژه ها:

Acrylic-Melamine ، Automotive Basecoat /Clear Coat ، Basecoat Pigmentation ، Weathering