Influence of weathering on physical properties of clearcoats

In this paper investigations concerning the weatherability performance of different clearcoat systems (IK, 2K) with various aromatics concentration in the polyol components will be presented, The analyses resulted after each 100 h accelerated weathering in a period of total 1000 h. Chemical degradation processes were analysed by means of FT-IR spectroscopy. For the physical investigations were used: dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), investigation of the surface topography, contact angle measurements to determine the surface tension and gloss measurements. Especially, the mechanical investigations proved the changes in properties as remarkably suited. Already after a short exposure time these methods yielded information about the weathering behaviour of the investigated clearcoat systems. (C) 2001 Elsevier Science B.V. All rights reserved.