Preparation and properties of nonionic waterborne epoxy resin

Most waterborne epoxy resin emulsifiers are inactive, and the free emulsifier will precipitate out during the curing of the coating film, which will seriously affect the water resistance, solvent resistance, and hardness of the coating film. Herein we prepared a new type of nonionic active epoxy emulsifier. First, 1,4-butanediol diglycidyl ether reacts with polyethylene glycol at a higher temperature to form an epoxy-terminated modified hydrophilic segment. Then 2,4-toluene diisocyanate link the hydrophilic segment and the epoxy resin E-31 (according the reactivity of the hydroxyl group on the epoxy resin E-31) to obtain an emulsifier for emulsifying epoxy resins. The synthesized emulsifier's cloud point is 89 degrees C and hydrophilic-lipophilic balance is about 13.1. The most suitable condition of the phase inversion is that the emulsification temperature is 60 degrees C and the stirring speed is 1500 r min(-1). The coating films obtained from synthesized emulsifier is dense and uniform with excellent mechanical properties.