Preparation of UV-curable waterborne polyurethane-acrylate emulsions
Researchers at Tianjin University, School of Chemical Engineering and Technology, have studied the molecular structure of UV curable waterborne polyurethane acrylate (UV-WPUA) emulsions. The investigation showed in particular three outstanding properties.
Polyurethane acrylate oligomer terminated with multiple unsaturated bonds was prepared using isophorone diisocyanate (IPDI), methylene diphenyl diisocyanate (MDI), and polyols as monomers, using 2,2-dimethylol propionic acid (DMPA) as hydrophilic chain extender, together with pentaerythritol triacrylate (PETA) as end-capper.
PETA should be used as end-capper
The UV curable waterborne polyurethane acrylate (UV-WPUA) composite emulsion was obtained by mixing the PUA oligomer with certain content of reactive diluents and then dispersing the mixture in water. The molecular structure of the polyurethane prepolymer, PUA oligomer, and UV-cured polymer was investigated by FT-IR. The influence of the composition and content of the diluents and end-capper on UV-WPUA properties, including the emulsion stability, thermal property, water resistance, adhesion, hardness, glossiness of polymer film were studied. The results showed that the WPUA emulsion has excellent stability, and the UV-cured film features good hardness and remarkable water resistance when PETA is used as end-capper and the end-capping ratio of the polyurethane prepolymer is 70% and DPHA/DPGDA (mass ratio 1:1) is used as diluent.
The study is published in: Journal of Applied Polymer Science.
