Radiation curing technology: An attractive technology for metal coating

The introduction of new tailor-made (meth)acrylated oligomers has extended the potential use of the radiation curing technology to metal coating applications where adhesion, flexibility and corrosion resistance are of prime importance. In this paper, we discuss the properties of three fairly simple clearcoat systems spanning a range of glass transition temperatures between ≈10 and 70 °C. The systems were obtained by combination of two original urethane acrylate resins and two reactive diluents.Practical performance tests typically used to establish coating profiles in the metal industry (i.e., mechanical testing, adhesion, salt-spray test, etc.) were performed on ultraviolet (UV)-coated galvanised steel. In addition, the barrier properties of coated steel panels were systematically investigated at different coating thicknesses using electrochemical impedance spectroscopy. These results are analysed in terms of relevant physico-chemical characteristics such as conversion, volume contraction, swelling, viscoelastic and tensile behaviour determined on free-standing coating layers of the three formulations.