In order to improve the mechanical and chemical properties

especially the solvent resistance of the cast films formed from normal waterborne polyurethane (PU) dispersions

a novel ultraviolet (UV)-curable epoxy and acrylate-modified waterborne polyurethane dispersion (UV-EP-AC-WPUD) and its film with high crosslinking density and excellent film properties were prepared and studied.4% epoxy resin E-20 was introduced in PU chain by grafting reaction between epoxy resin and polyurethane prepolymer terminated with the –N=C=O group.The C=C bond was introduced in PU chain by the chain-extending reaction of —NCO in polyurethane prepolymer with two hydroxyl vinyl monomers PEDA and single-hydroxyl vinyl monomers PETA

and the obtained maximum C=C content was up to 4.65 meq·g-1. 3% photoinitiator Irgacure 2959 was used to initiate the polymerization of C=C bond in cast films

and the gel content of the UV-EP-AC-WPUD films could reach up to 91% after 12 s UV-radiation

which meant the polymerization rate and crosslinking rate of C=C bond was high

and the obtained UV-EP-AC-WPUD film was highly-crosslinked and insoluble in solvent.The water absorption

solvent resistance

gel content

pendulum hardness and tensile strength of the cured film were studied

and Fourier transform infrared spectroscopy (FTIR) analysis and film study results showed that the UV-cured EP-AC-WPUD films including epoxy resins and hydroxyl-containing vinyl monomers had excellent mechanical and chemical properties. Thermo gravimetric analysis (TGA) also indicated that the thermal stability of the film was improved significantly.