| Water-borne polyurethane replacing solvent-based polyurethane is an important direction of. polyurethane industry development today. Water-borne polyurethane includes mono-package and two-package system. Compared to the latter, the former possesses some characteries such as good storage stability, low toxic and convenient use, and attracts more attentions. In this paper, mono-package water-borne polyurethane was prepared with aliphatic isocyanate and polyether as main chemicals, and was modified with epoxidized hydroxybutyrate glue (EHTPB) and inorganic nanoparticles for improving the water resistance and the solvent resistance, the main contents and conclusions are described as follows:(1) mono-package water-borne polyurethane was prepared with aliphatic isocyanate and polyether as main chemicals, and the effect of technical conditions such as reaction temprature, reaction time, catalyst, ratio of NCO to OH (value of R) and amount of DMPA on the viscocity and stability of polyurethane dispersion and properties of polyurethane coating, and the results show that polyurethane prepolymer with suitable viscocity and good dispersibility can be obtained by controlling the reaction temprature at 90℃for 2.5h.during the prepolymerizing process and at 80℃for 1h during during chain-extending process. To prepare excellent polyurethane dispersion, the R value and the amount of DMPA should be 1.4-2.0 and 6%, respectively.(2) Epoxidized hydroxybutyrate glue (EHTPB) and TMP were used to modified the mono-package water-borne polyurethane. The synthesis of the prepolymer and the particle size and stability of the dispersion were characterized by fourier transform infrared spectra (FTIR) and laser particle size analyzer, respectively, and coating properties such as water resistance, solvent resistance and heat stability were also characterized by testing contact angle, electrochemical method, thermogravimetric analysis, SEM and common coating testing method. The results show that the water resistance, solvent resistance, base corrosion resistance and heat stability of the polyurethane coating are distinctly imroved with the addtion of 40% epoxidized hydroxybutyrate glue and 7% TMP in the prepolymer.(3) The epoxidized hydroxybutyrate glue modified waterborne polyurethane was also improved by TiO2-SiO2 nanoparticles modified with KH560, and the resulting dispersion was characterized by ultraviolet spectrophotometry and laser particle size analyzer, the structure and properties of the film were characterized by using thermogravimetric analysis, tafel polarization curve, SEM and common coating testing method. The results show that a waterborne polyurethane with satisfactory performance was developed, and the tensile strength, hardness, adhesion and solvent resistance of the coating are increased when appropriate TiO2-SiO2 nanoparticles were added.
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