Abstract:

Traditional ultraviolet (UV) inks have the advantages of low viscosity, fast curing speed, and wide application range. However, there are disadvantages such as use of organic solvents and low degree of crosslinking. In this paper, styrene and acrylic acid are copolymerized by free radical polymerization to form aqueous prepolymer. Secondly, a tetraacrylate functional reactive diluent is prepared from glycidyl methacrylate (GMA) and ethylenediamine. Finally, a UV-curable aqueous ink is prepared using an aqueous prepolymer, a reactive diluent, a photoinitiator, and a small amount of solvent. The effects of the type and mass fraction of the photoinitiator, the relative molecular mass and mass fraction of the prepolymer, the structure and mass fraction of the reactive diluent on the photocuring speed and wear resistance of the UV ink are investigated. When the prepolymer has a relative molecular mass of 1.98×10⁵ and a mass fraction of 30%, a photoinitiator mass fraction of 4%, a reactive diluent functional group number of 4, and a mass fraction of 40%, the photocuring rate of the UV aqueous ink is 1 s. After 50 times the wear quality loss is 9%. The UV aqueous ink prepared by the method can be used for flexographic printing, gravure printing, and digital printing.

Key words: ultrabiolet water-based ink, prepolymer, photocuring, reactive diluent