Preparation Of Silicon Modified UV-curable Waterborne Resins And Film Properties

Recently, waterborne coatings have gained increasing attention due to strict environmental regulations on the emission of volatile organic compounds (VOC) from solvent-borne coatings. VOC in paints and coatings is of particular interest due to their adverse effects on the environment. Using water instead of hazardous solvent is the rational behind waterborne coatings which aims for total reduction of toxicity without compromising environmental concerns. At present, however, waterborne coatings are considered unsatisfactory as the application conditions are often critical; they are difficult to apply because of their rheological behavior and poor wetting, temperature and humidity have to be strictly controlled for correct curing conditions, etc. Moreover, once applied, their performances are usually inferior to the traditional coatings.The use of waterborne coatings in combination with the UV-curing technique is also very attractive since the UV-curing process offers many advantages too.The advantages of UV-curable waterborne coatings are obvious, however, their poor wetting, thermal and mechanical properties have limited their applications, so they need some modifications. For many years silicon intermediates have been used to modify organic resins to increase their properties. Therefore, one possibility to get higher performance materials is incorporating silicon in the polymer network. UV-curable waterborne coatings modified with silicon can be used to formulate coatings having high hardness with excellent flexibility, thermal stability and better wetting.Here, we synthesized a series of nano SiO2/functionalized siloxane modified UV-curable waterborne coatings by incorporating the nano SiO2/functionalized siloxane into the organic resins. The films of the nano SiO2/functionalized siloxane modified UV-curable waterborne coatings show excellent properties such as surface hardness, water resistance, heat resistance, flexibility and mechanical properties owing to the excellent bond strength of the Si-O-Si. In this study, we synthesized a series of nano SiO2 modified UV-curable waterborne polyurethane emulsions (SiO2-PUs) by the effect of hydrogen bonds between nano SiO2 and polyurethane chains. A detailed study of the effect of nano SiO2 on the heat stability, water resistance and mechanical properties of the films was carried on. It was found that incorporating of nano SiO2 can improve the water resistance of the films. When the nano SiO2 content was 6%, the water absorption of the films was stable at 10.28%. It was also found that incorporating of nano SiO2 can improve the thermal stability and many mechanical properties of the films. The coating thus formed can serve as a good scratch, abrasion, water resistant and heat resistant coating and can find applications in various practical situations.Here, we synthesized a series of KH550 modified UV-curable waterborne polyurethane emulsions (Si-PUs) by incorporating the KH550 into the end of the PUs chains. The Si-PUs was characterized by using FTIR spectroscopy and the results showed that the KH550 had been successfully introduced into the polyurethane chains. It was found that incorporating of KH550 can improve the thermal stability, water resistance, and many mechanical properties of the films. It can be seen that when the KH550 content was greater than 3.433%, the mechanical properties of the films did not significantly improve while maintaining good water resistance. The best content of KH550 and the ratio of reactants for the modification obtained by the experiment can provide information to the research of modifying UV-curable waterborne polyurethane and practical application.In this study, we synthesized a series of 0 VOC KH560 modified UV-curable waterborne epoxy acrylic dispersions (Si-EAs) by incorporating the Tetrahydrophthalic anhydride and the KH560 into the end of the epoxy acrylate chains. The Si-EAs was characterized by using FTIR spectroscopy and the results showed that the KH560 had been successfully introduced into the epoxy acrylate chains. It was found that incorporating of KH560 can improve the thermal stability, water resistance, and many mechanical properties of the films. The experiment can provide methodological guidance to the research of modifying UV-curable waterborne epoxy acrylic resin.