Development of Acrylic-Epoxy Hybrid System for Steel Structure Corrosion Performance

The objective of this study is to develop hybrid coating system using organic resin for automotive and marine applications. The hybrid systems were prepared by blending acrylic polyol resin with epoxy polyol resin in various weight ratios. A series of acrylic(A) - epoxy(E) resin blends with the ratio of 10A:90E, 20A:80E, 30A:70E, 40A:60E, 50A:50E, 60A:40E, 70A:30E, 80A:20E and 90A:10E have been prepared and applied on the pre-treated cold rolled mild steel panels. The dry film thickness was maintained within the range 40 mu m to 80 mu m. The panels were allowed to cure under ambient air condition for one week prior to testing. The physical, mechanical, structural, thermal and corrosion properties were investigated to obtain the best formulation. From these studies, the blending system with 80A20E and 90A10E exhibit good physical, mechanical and corrosion properties. FTIR showed crosslink between the components of the binders. DSC showed that the Tg of these binders range between 150 degrees C to 200 degrees C. Corrosion resistance and mechanical properties of the coating were studied and characterized. This paper will discuss the study of coatings in accelerated exposure and the analysis of EIS data from such study. It is observed that, of the nine coating formulations, 90A:10E has been found to perform well as effective and durable hybrid coating.