Mar Behavior and Quantitative Evaluation of Urethane-Acrylate Coatings with a Different Gloss

Mar behavior and visibility were investigated by applying a constant load to various gloss-coated urethane-acrylate surfaces. Using a area-contact scratch tip which can apply a relatively low stress level to the coated surfaces, the mar damages were generated on the surfaces. When evaluating the mar-induced damage by means of delta-gloss (Delta G) and delta-luminance (Delta L) with existing test methodologies, an increase in constant load on the same gloss-coated surface leads to an increase in Delta G and Delta L. However, these are not suitable for evaluating and comparing the surface damages of different gloss-coated samples because of a disagreement between the measured values and the mar visibility. It is shown that new mar test assessment proposed in this work not only can be used to quantitatively evaluate the mar damage, but also accounts for the correlation that the increases of the normalized gloss and luminance on coated surfaces correspond with an increase in the mar visibility.