Syntheses And Properties Of Waterborne Polyacrylate/Polyurethane Emulsions

Water -borne polyurethane emulsion was prepared from 2,4-toluene-diisocyanate (TDI), isophorone diisocyanate (IPDI), polyether diol (PPG), dimethlylol butanoic acid (DMBA), 2-butyne-1,4-diol(BDO) and ethylene diamine (EDA) through self-emulsified method. Polyurethanes with different properties were synthesized by changing the polymerization method, NCO/OH values, DMBA contents, EDA contents and BDO contents. The effects of different copolymers and polymerization methods on the particle size, water-resistance and hardness of the PU film were explored in this paper. Polyurethane emulsion particles were demonstrated by means of SEM, and the mechanical properties was investigated by mechanical experiment.In order to improve the properties of PU, polyacylate (PA) emulsion was prepared in this work, then the PA emulsion and PU dispersion were blended by three methods. Besides,the mechanical stir method, high pressure homogeniser (HPH), the aqueous acrylic-polyurethane hybrid emulsions (PUA) were also prepared by the following method:at the stage of dispersion for PU prepolymer, the PA emulsions were used as deionic water. Also, the effects of different parameters on the particle size, water-resistance, stability, and hardness of the PUA film were investigated. The structure of PA particles inside the PUA hybird particle was prepared by this method.The pencil hardness of PUA film is more than H and its swing hardness is more than 0.6. After sunk in tap water for more than one week, the water absorption of the PUA film is only 8%.Finally, the waterborne polyacrylate modified polyurethane dispersion with high performance was prepared.