Study On Crosslinkable Acrylic Resin Modified Two Component Waterborne Polyurethane Emulsions

Waterborne polyurethane is a new polyurethane system in which solvent is replaced by water. Because of its impollution and good properties it is used widely. The research synthesized waterborne two component polyurethane which was based on polyacrylate modified waterborne polyurethane emulsions. This is a new development of the synthesization. And the emulsion polyurethane graft copolymerization modified by acrylate with core-shell structure has been prepared by graft copolymerization, which is a new synthesization development of modified polyurethane.The results of study showed that polyesterglycols and extender influenced emulsions properties heavily. The film characteristics of tensile strength,hardness increased obviously due to the exist of hydrazine group. When hydrazine group compound content is under 4 percent on polymer solids the PU emulsion is stable.The monomer,temperature and the keto group compound influenced the polyacrylate emulsions properties heavily. As the increase of the keto group compound, the particle of emulsion got bigger and the stability went worse. When keto group compound is under 6 percent on polymer solids, the stability of PA is good. Because of the crosslinking reaction between keto group and hydrazine group of the crosslinkable polyurethane/acrylic polymer composite emulsion, the properties of emulsions are better than unmodified PA and PU emulsions. When keto group equal to hydrazine group by mol the properties of emulsion was best, and the emulsion act as polyols crosslinked with water reducible polyisocyanates its properties were near to solvent two component PU coating, and the price was lower. It could be applied in coatings include textile,leather and construction.