Factors affecting performance of polyurethane-acrylate hybrid emulsion
Because of the excellent properties and wide application, the water borne polyurethane emulsion modified by acrylate has become the research hot spot in coating industries.First, the water borne polyurethane prepolymer(PU) was prepared with the method of emulsion polymerization in situ, then through the free-radical emulsion polymerization, polyurethane-acrylate(PUA) hybrid emulsion was synthesized by adding initiator and methyl methacrylate(MMA).The hybrid emulsion was characterized by FT-IR, gel permeation chromatography(GPC) and Malvern particle size analyzer.Such factors as:NCO/OH ratio, the amounts of dimethylol propionic acid (DMPA) and methyl methacrylate, and triethylamine(TEA)/DMPA mole ratio, which affected the properties and appearance of the PUA emulsion were discussed.Prepared with the technology parameters 1.3—1.4 of NCO/OH ratio, about 2.6% of —COOH content, 20%—30% of MMA content, and 90%—100% of mole ratio of TEA/DMPA, the PUA emulsion showed good overall properties.