Abstract
Steel is generally coated with the purpose of improved anticorrosive protection and aesthetic properties. In the early 90’s, few strict environmental protection regulations boosted the replacement of the traditional solventborne coatings and consequently development of waterborne paint technologies. In this view, the aim of the present work is the study of the cathodic electrodeposition of a waterborne acrylic binder in presence of different color pigments considering the effect on the aesthetic properties of the coated panels in function of accelerated exposure. Essentially, the activity was divided into two stages. First of all the optimization of the deposition parameters was carried out in order to obtain, in terms of thickness and physical barrier property, a suitable coating layer without the pigments. Next, the influence of pigments incorporation into the bath on the aesthetic properties during UV-B radiation exposure was studied. The film thicknesses were found about 20 µm. Preliminary estimations of the anticorrosive properties using electrochemical test have shown a quasi-capacitive behaviour of the paint. The magnitudes of the |Z|0.01Hz have been verified in the order of 1011 Ohm.cm2 for about two weeks of immersion indicating a good corrosion protection properties. After 500 hours under UV-B radiation, changes were verified on both, the coatings morphology and chemical structure.
Introduction
The use of organic coatings to paint metallic substrates provides both corrosion protection and prolonged service life to the painted metal alongside aesthetic or visual appearance. In addition it is a relatively cost effective technology consequently it is widely used in many fields of industry. 1-2 In view of corrosion protection, it is well-known the great efficiency of paint systems based on organic solvents, the so-called solventborne coatings. However, forced by environmental and human health concerned directives and regulations the emissions to the atmosphere of volatile organic compounds (VOCs), consequently, the use of solventborne paint systems has been limited. 3 As a result, specialists on the field of paints were encouraged towards development and use of solvent less technologies to coat metals. 4-5
