Synthesis and Application of Blocked Waterborne Polyurethane Crosslinker

In this paper, the blocked waterborne polyurethane crosslinker were prepared by polyaddition reaction with isophorone diisocyanate (IPDI), polypropylene glycol-2000 (PPG MW2000) and dimethylolpropionic acid (DMPA) as internal emulsifier, sodium bisulfite (NaHSO3) as blocked agent in presence of dibutyltin dilaurate (DBTDL) as catalyst. The Fourier transform infrared spectrum analysis (FT-IR) showed that the isocyanate groups of blocked waterborne polyurethane crosslinker are completely blocked. The differential scanning calorimetry (DSC) analysis showed that the deblocking temperature of blocked waterborne polyurethane crosslinker is between 88.3C~92.4C. Application results showed that the blocked waterborne polyurethane crosslinker can significantly improve the tensile strength and water resistance of waterborne polyurethane membrane.