Study On Synthesis Of Water-Based Polyurethane Emulsion Modified By Acrylate

A waterborne polyurethane dispersion(PU) was synthesized by the reaction of polyester glycol(PBA2000), di-ethylene glycol(DEG)and di-methylol propionic acid(DMPA) with toluene di-isocyanate(TDI), and a coatings based on above mentioned emulsion was also made. The factors influencing the properties of waterborne polyurethane film were discussed. The results showed that the waterborne polyurethane coating demonstrated good mechanical properties, when the ratio of NCO/-OH was equal to 1.2-1.4 and the amount of-COOH was 1.8%-2.0%.Furthermore, an ambient polyurethane-acrylate hybrid emulsion (PUA) with core-shell structure was prepared with MMA through a seed emulsion polymerization. In comparison with that of PU, the film of PUA demonstrated better properties in the hardness, water resistance and solvent resistance, etc. Through the discussion of modification technique, the ratio of polyurethane to acrylate, factors which influence the stability of polymerization process, the reasonable ratio of PU to MMA, initiator system and pH value of the seed emulsion were determined in this paper.Besides, in order to improve the comprehensive performance of the PUA film, an new kind of hybrid emulsion was prepared with MMA, HEA, and DAAM as functional monomers, and with ADH and an urethane as double curing agents through a seed emulsion polymerization. In comparison with that of PU, the film of PUA demonstrated better properties in the hardness, water resistance and solvent resistance, etc. due to the use of a double crosslinking system. The degree of the crosslinking of the film could amount to more than 90%.