Study On High Performance UV Curable Resin Systems

UV-radiation curing has become a well-accepted technology for replacing conventional thermal curing process in the development of new products. This technology has many advantages such as low energy consumption and high productivity as well as big efficience, therefore this process has been widely used in manifold industrial applications, mainly for prodcing coatings, printing inks and adhesives. UV curing coatings usually consist of oligomer, reactive diluents and photoinitiators, of them oligomer is the key component which affects the property of curing film such as surface hardness, flexibility, adhesion etc.In the thesis, unsaturated polyester (UP) and epoxy acrylate (EA) is used as oligomers. Unsaturated polyester resin is a solution of polymer condensed by saturated di-alcohols and di-acids (including saturated and unsaturated di-acids) solved in active monomers (such as styrene). It has been widely used in many areas due to its good comprehensive properties and multiple shaping techniques. The commonly used oligomer is EA resin, the curing film consisting of EA resin has some good properties such as good gloss, high hardness and excellent chemical resistance. UV-curable epoxy acrylate oligomers were synthezed by using E-51 Epoxy resin, and characterized. A UV curing system is designed and propeared by using dipropylene glycol dimethylacrylate as the reactive diluent, and 2,4,6-trimethylbenzoyldiphenyl phosphine oxide as the photoinitiator.Heat resistance of unsaturated polyester and EA is not good enough to be used in areas requiring high heat resistance. Bismaleimide (BMI) is the typical representive eample of heat resisitance resins. In order to meet the increasing requirement of heat resistant resins by modern industries, a novel kind of UV-curable heat resistant modified unsaturated polyester resins and EA resin by bismaleimide is developed, and the preparation parameters as well as the relationship of component-structure-property are discussed. Results show that BMI can not be cured by UV technique, but BMI modified UP resin and EA resin is UV-curable. The curing progress, the effects of photoinitiators on the relationship of exposure time and conversion, and the integrat properties of films including adhesion, water and chemical as well as heat resistance have been evaluated. The results indicate that compared with unmodified resins, the addition of BMI can improve not only the water and chemical resistance, but the thermal stability also.