Preparation And Research Of Fluorinated Acrylate Waterborne Polyurethane UV Curing Composite Coatings

Traditional polyurethane coatings have a large number of organic solvents as dispersants the volatile organic matter?VOC?will cause certain pollution and harm to the environment and human health.So with the increasing awareness of environmental protection,the research of waterborne polyurethane coatings with water as dispersant has attracted much attention.However,due to the introduction of hydrophilic groups,the comprehensive properties of waterborne polyurethane film is relatively poor,so it should be modified to meet the requirements of all aspects.Fluorinated acrylate has good prospects for development due to its good heat resistance,cold resistance,corrosion resistance and electrical insulation.UV curing technology has the advantages of high curing speed,low temperature,low energy consumption,low cost,wide application range and low equipment requirements.Therefore,a UV curable fluorinated waterborne polyurethane coating can be developed by introducing fluorinated acrylate and light curing groups.The contents and achievements of this thesis are as follows:?1?Using acetone method,with Hexamethylene Diisocyanate?HDI??Polypropylene glycol 2000?PPG2000?,dimethylolpropionic acid?DMPA?,and 1,4-Butylene glycol?BDO?as raw material,Triethylamine was used as neutralizing agent to prepare prepolymer,and the end was sealed with pentaerythritol triacrylate?PETA?.By discussing the reaction conditions,the optimum reaction conditions for the synthesis of PETA-WPU were found:the temperature was 85?and the amount of catalyst was 0.2wt%.The PETA modified waterborne polyurethane emulsion was prepared for photocuring film.The structure of the product was characterized by Fourier transform infrared spectroscopy.It was found that there were a large number of carbamate bonds in the structure of the product,which indicated that the polyurethane was successfully synthesized.Thermogravimetric analysis and differential scanning calorimeter were used to detect the thermal properties of the products.?2?On the basis of the previous experiment,a large number of double bond products were synthesized at the end of the molecular chain,and then the aqueous polyurethane composite emulsion containing fluoroacrylate was prepared by graft copolymerization of the seed emulsion and trifluoroethyl methacrylate.And the UV curing coating was made.The water absorption of fluorine-containing polyurethane film was compared with that of non-fluorinated polyurethane film.It was shown that the introduction of fluorine could obviously enhance the water resistance of the film,and the structure of the product was characterized by Fourier transform infrared spectroscopy.The characteristic peak of-CF₂was found in the structure of the product,which indicated that fluorine had been successfully inserted into the chain of polyurethane,and the thermal properties of the product were examined by thermogravimetric analysis and differential scanning calorimetry,and it was found that the product had good thermal stability.?3?The modified silica sol was prepared by sol-gel method.The oligomer prepared in experiment?1?was modified and the UV-curable hybrid coating of waterborne polyurethane was prepared.By thermogravimetric analysis?TGA?,the thermal stability of the hybrid coating was compared with that in experiment?1?,and it was found that the addition of silica sol could obviously enhance the thermal stability of the product,and the hybrid coating had good thermal properties by thermogravimetric analysis.