Synthesize Of The New Water-Based Polyurethane Resin And Study Of Electrophoresis Process For Water-Based Polyuretuane Coating

In this dissertation, the synthesis of vvaterborne polyurethane resins and relative properties were studied。 It consists of four main parts of (1) the preparation process of waterborne polyurethane, (2) modification of water-based polyurethane dispersion by the epoxy.resin and the influence of epoxy on the property of water-based PU dispersions, (3) modification of water-based polyurethane dispersions by aerylate and the effect of acrylate on the performance of PU dispersion, (4) the effect of electrophoresis process parameters on the performance of water-based polyurethane coating.First, we discussed the effects of process variables such as initial NCO/OH(R index), reaction temperature of hydrophilic extender capping reagents and initiators etc. on the performance of water-based polyurethane resins. The results showed that the hardness of film became harden with increasing of wt% of NCO group, and while increasing concentration of DMPA, the size of particle became smaller, viscosity of PU electrolyte resin increase, water resistant became weak. When netrolization degree of TEA is 0.75, the properties of the film is most desirable. The performance of the blocked water-based polyurethane coating was belter than that of the non-blocked water-based polyurethane coating.Second, the preparation of water-based polyurethane dispersions modified by epoxy resin was studied. The results showed that with increasing of the epoxy resin content, the water resistance, solvent resistant, the rigidity and shine of the electrophoretic film were improved significantly.Third, in order to overcome the poor solvent resistance, water resistance and hardness of the waterborne polyurethane dispersion, the aerylate was used to modify the structure of the water-based polyurethane, the performance of the water-based...