Preparation and conductive processes of UV curable solvent/water-based ink

Ultraviolet curing (UV) water-based ink has the advantages of low viscosity, high gloss, and wide application range. However, there are some defects such as slow curing speed and low cross-linking degree. In this paper, the copolymer p(GMA-r-AA) was prepared via traditional radical polymerization using glycidyl methacrylate (GMA) and acrylic acid (AA) as monomers, and then p(GMA-r-AA) was modified by 2-hydroxyethyl methacrylate (HEMA) to obtain acrylic prepolymer P(GMA-r-AA)-g-HEMA with double bonds. Triethylenetetramine reacted with GMA to obtain a multifunctional reactive diluent triethylenetetramine hexamethacrylate glycidyl amide (TGMA). Fourier transform infrared (FTIR) spectroscopy combined with hydrogen nuclear magnetic resonance spectroscopy (1H NMR) was used to characterize the structures of the prepolymer P(GMA-r-AA)-g-HEMA and the reactive diluent TGMA. Three ingredients were needed to prepare UV curable ink: photoinitiator, multifunctional reactive diluent (TGMA), and acrylic prepolymer P(GMA-r-AA)-g-HEMA. The effects of the mass fraction and relative molecular weight of P(GMA-r-AA)-g-HEMA, the type and mass fraction of the photoinitiator, the number of functional groups, and the mass fraction of TGMA on the UV ink curing speed and wear resistance of the ink film were discussed. At a mass fraction of 1% for the photoinitiator TPO, the mass fraction of the reactive diluent was 55% with 4 functional groups, and the prepolymer had an average relative molecular mass of 5.63 × 104 g/mol. The UV water-based ink completed curing in 0.1 s, and the mass loss abrasion was 2–5% after 50 times. Finally, the UV ink was used to prepare UV conductive magnetic ink. The UV conductive and magnetic ink can be cured into a film in 0.1 s, no peeling phenomenon, with good magnetic properties.