Synthesis And Properties Of Highly Emulsifiable UV Photopolymerization Emulsifers

Ultraviolet(UV)curing waterborne coatings have the characteristics of high efficiency,convenience,environmental protection and solvent-free in waterborne coatings,which could solve the problems of low steam pressure,toxicity,irritation and insecurity.Therefore,it has great development potential in the coating industry.Emulsifier is important component in Ultraviolet(UV)curing waterborne coating,which plays an important role in the emulsion dispersion process of resin or monomer.In recent research,UV polymerization emulsifier has attracted great attention,for its structure contains reactive groups,which participate in the reaction to make emulsifiers become part of the paint film,which can enhance the stability and water resistance of paint.In this paper,by using polyoxyethylene sorbitol Tween X(X=20,40,60)emulsifier,and ethyl isocyanate acrylate(AOI),through the addition reaction of-OH and-NCO,the C=C structure is introduced into the molecular chain of emulsifier,thus the emulsifier can participate in the photopolymerization reaction,and then improves the water resistance of the paint film.The main research contents are as follows:1.Three polymerizable emulsifiers Tween 20-AOI,Tween 20-2AOI and Tween 20-3AOI were prepared by the reaction of Tween 20 emulsifier and ethyl isocyanate acrylate(AOI)according to different mole ratios.Molecular weight test,rheological properties and spectra were used to characterize the structure of emulsifier.The emulsifying properties of emulsifier were investigated by critical micelle concentration(CMC),hydrophilic lipophilic equilibrium(HLB)value and emulsifying strength composite index.The water resistance of paint film was characterized by High temperature water resistance and water absorption swelling rate test.The results show that with the increase of AOI content in Tween20 emulsifier,the molecular weight and viscosity of Tween 20-AOI,Tween20-2AOI and Tween 20-3AOI increase,while CMC and HLB value decreases.The emulsifying property is Tween 20-2AOI >Tween 20-AOI>Tween 20-3AOI.The water resistance property is Tween 20-3AOI >Tween 20-2AOI> Tween 20-AOI.In this result,Tween 20-2AOI is relatively best among the three emulsifiers.2.Tween X(X=20,40,60)emulsifier reacts with AOI with the molar ratio of 1:2 to synthesize Tween 20-2AOI,Tween 40-2AOI and Tween 60-2AOI.The results show that the length of carbon chain of Tween 20-2AOI,Tween 40-2AOI and Tween 60-2AOI emulsifiers increases,the molecular weight and viscosity of emulsifier increases,while CMC decreases,HLB value is basically unchanged,but the emulsifying property is obviously decrease.The water resistance of paint film is good.By comparing the emulsification and water resistance emulsifiers of three kinds of photopolymerizable emulsifiers,Tween 20-2AOI is a kind of emulsifier with high emulsification and water resistance.3.The UV curable performance of Tween 20-2AOI was verified by real-time RT-FTIR spectroscopy,and the photopolymerization rate of Tween 20-2AOI was investigated in the presence or absence of oxygen.Finally,Tween 20-2AOI was successfully applied to the UV-curing waterborne coating,and a waterborne coating with good stability,high hardness of paint film pencil,good adhesion and strong water resistance was prepared.