光固化聚氨酯丙烯酸酯涂层的固化动力学及其光稳定化研究

Study on the UV-curing Kinetics and Photostabilization of Polyurethane Acrylate Coatings

研究了脂肪族和芳香族聚氨酯丙烯酸酯类低聚物的光固化动力学和反应型受阻胺 ( r HALS)对光固化聚氨酯丙烯酸酯涂层的光防护效果。加速老化实验结果表明 :r HALS的光稳定体系可有效地将试样的黄度指数 (YI)控制在较低水平内 (辐照时间 10 0 0h ,YI <1%～ 2 % )。含有 r HALS的光固化涂层比相应的商品HALS具有更优越的耐光氧老化性能。

The UV curing kinetics of several urethane acrylates were studied in the presence of 2,2,6,6 tetramethyl 4 piperidinyl and 1,2,2,6,6 pentamethyl 4 piperidinyl derivatives as reactive HALS (r HALS). The photo stabilizing effects of r HALS were evaluated using yellowness index(YI) as a characterizing parameter. It is found that r HALS are superior to the corresponding commercial HALS suchas Tinuvin 770 and Tinuvin 292, which may be attributed to better dispersion and reduced migration (or evaporation) in the matrix. With 325 nm monochromatic radiation, we show that the increment of YI is directly proportional to the light intensity absorbed by UV cured coatings of oligomer CN 964 at early stage of irradiation.