| Water based polyurethane can be used in a wide range of fields because of its adjustable hardness and good flexibility. But as the base materials for water based inks and anticorrosive coatings, the single polyurethane emulsion whose cost and properties of the solid content, water resistance, abrasion resistance, corrosion resistance, aging resistance and so on are all inadequate. In view of this, different types of modified waterborne polyurethane composite emulsion were prepared by two kinds of modified methods in this study and applied in the field of water-based ink and water based anticorrosive coatings respectively.(1) Study on preparation and application of cross-linked polyurethane composite emulsion modified by epoxy (PUE)Epoxy modified polyurethane composite emulsion (PUE) was prepared using Epoxy resin (CYD-011) as modified resin, Toluene diisocyanate (TDI), polyether glycol (GE-210) as main materials by the way of pre-polymerization. Gravure water based inks was prepared with modified resin as binder and carbon black as pigment.The effect of such factors as the initial R (NCO/OH), the type and content of Epoxy resin on the performance of emulsion and film were discussed. Additionally the amounts of epoxy resin on the property of the water based inks were researched as well. It was found that PUE has excellent comprehensive performance with the initial R (NCO/OH) was 7.5, CYD-011 as the modified resin and which content was 6%. The Water based inks has ideal gloss and rub resistance, while water resistance, alkali resistance could reached grade 5 and met the requirements of practical application.The emulsions were characterized by FTIR and DSC. The results showed that epoxy resin and polyurethane have occurred graft reaction to achieve the purpose of the modification. The micelle was homogeneous structure.(2) Synthesis of double-Crosslinking PUEA composite emulsion and research of its anticorrosive performanceA double crosslinking PUEA emulsion which was used for metal anti-corrosion was successfully synthesized by pre-polymerization method using CYD-014 as pre-crosslinking agent, GMA as post crosslinking agent, and TDK GE-21CK DMPAs MMA as the main raw materials.The factors during the synthesis process of double crosslinking PUEA emulsion were discussed, such as the content of DMPA and GMA on the properties of the emulsion and the film. Experimental results showed that the dosage of DMPA and GMA had an important effect on the properties of PUEA emulsion and film. The emulsion had good performance and stability when the DMPA content was 7.5%, GMA content was 3%. The baking film was endowed with excellent hardness, impact resistance, mechanical property and the anticorrosion performance. Meanwhile the film had the lowest rate of water and ethanol absorption.The conditions of crosslinking curing process were explored through the degree of crosslinking of the film observed by Scanning Electron Microscopy (SEM), and the study on anti-corrosion properties of coatings with immersion experiments. The film properties of the post crosslinking PUEA were closely related to the baking temperature and baking time. The suitable film forming condition was 150?/20minThe molecular structure of polymer were characterized through Fourier Transform Infrared Spectroscopy (FTIR), and the results are in accord with the experimental design. Transmission Electron Microscopy (TEM) shows that the shape of the particles was uniform sphere with obvious core-shell structure, and the particle's size was about 70nm. The thermal gravimetric analysis (TG) method was used to verify the process and conditions of the coating. The curve indicated that the heat resistance of the final film is good. |
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