Synthesis and Application of UV-Curable Non-Isocyanate Urethane-Functional Acrylates for Coatings and 3D Printing

Traditional nonisocyanate polyurethane coatings require long curing times or high temperatures and use a large amount of organic solvents, which leads to low productivity, energy waste, and environmental pollution. This study demonstrates a green chemistry method for synthesizing a series of solvent-free vinyl-based amine-derived tris(hydroxypropyl urethane) methacrylates (NI-AUMAs) that can be rapidly cured at room temperature without the use of toxic isocyanates. First, 4,5-epoxycyclohexane-1,2-dimethyl dicarboxylate diglycidyl ether cyclic carbonate (EDDC) was reacted with n-butylamine (BA), n-hexylamine (HA), and benzylamine (BZA), respectively, to synthesize a series of nonisocyanate amine-derived tris(2-hydroxypropyl urethane)s (NI-AUs). Then, the nonisocyanate amine-derived tris(2-hydroxypropyl urethane)s (NI-AUs) were reacted with methacrylic anhydride (MAAH) to prepare vinyl-based nonisocyanate amine-derived tris(hydroxypropyl urethane) methacrylates (NI-AUMAs), including nonisocyanate butylamine-derived tris(hydroxypropyl urethane) methacrylate (NI-BAMA), nonisocyanate hexylamine-derived tris(hydroxypropyl urethane) methacrylate (NI-HAMA), and nonisocyanate benzylamine-derived tris(hydroxypropyl urethane) methacrylate (NI-BZAMA). The structures of these NI-AUMAs were confirmed by FT-IR and 1H NMR. A series of nonisocyanate urethane-based UV-cured coatings (NI-UVC coatings) with good thermal stability, pencil hardness, adhesion, and chemical solvent resistance were prepared from NI-AUMA, photoinitiator (2-hydroxy-2-methylpropiophenone 1173), and polyethylene glycol diacrylate (PEGDA) or 1,1,1-tris(acryloyloxymethyl)propane (TMPTA). Additionally, the NI-AUMA resin synthesized in this experiment can also meet the requirements for the 3D printing of various highly complex models. In general, this study provides a green synthesis method for preparing NI-UVC coatings and 3D-printed products. Undoubtedly, this will greatly promote the development and application of environmentally friendly nonisocyanate urethane-based materials in coatings and 3D printing.