The Effect of Detergents on the Appearance of Automotive Clearcoat Systems Studied in an Outdoor Weathering Test

Abstract

The ability to predict the weathering performance of the clearcoat system over a short period of time is essential for the design and development of coating production. Thus, the primary objective of the present study is to investigate whether it is possible to predict the weathering performance of an automotive paint system through determination of surface roughness, R a , and micro-hardness before and after various weathering exposure times (0, 24, 168, 336, 504, 672 hours) and when employing two different detergent materials (house-use detergent and car wash detergent). The data were analysed using a pair-sample t-Test, with 0.05 level of significance. It was found that the total net of degradation in the clearcoat level during the first 24 hours was R a ≈ 30.3 nm (for surface roughness) and 1.358 HV (for the µ-hardness) when using the house-use detergent. In contrast, it was found to be R a ≈ 4.6 nm (for surface roughness) and 1.133 HV (for µ-hardness) when using the car wash detergent. Also, increased time of weathering (up to 672 hours) increases the R a and µ-hardness values. It can therefore be concluded that the effect of house-use detergent was more severe than that of car wash detergent on the clearcoat system.