| Résumé : |
Considering pigmented acrylate formulations the influence of various raw materials, the type of UV radiators, duration of exposure, and film thickness were studied. The criteria used included IR and UV/VIS spectrometry, radioscopy, etc. The size of the free spectral window as an indicator for the curing behaviour was shown to be of restricted relevance to white and coloured lacquers. Additionally, a similar estimate could be made of the pendulum hardness and of the maximal free curable film thickness as compared to the curing behaviour on wood. Moreover, the reflectance of the substrate had a large influence. An optimized mixture of acrylate oligomers with high reactivity and functionality, careful selection of type and amount of the photoinitiator system and stretching of the pigments with extenders permitted the development of white and black coating materials giving opaque films with good through and surface curing. A comparison was also made with reference to polyester systems and to cationically curing compositions. |
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Pigmented UV curable materials in EUROPEAN COATINGS JOURNAL (ECJ), N° 4/96 (04/1996)
