Ink is composed of pigments, solvents, binders, and other additives. Among these, the binder significantly impacts the ink’s rheology, viscosity, fineness, and printability. Traditional ink binders typically use highly toxic and volatile organic solvents such as toluene, isopropanol, and formaldehyde, which pose threats to the ecological environment and production safety. Currently, due to the control requirements of VOCs, more printing processes are shifting towards using eco-friendly inks such as water-based and UV inks. However, water-based inks have drawbacks like low gloss and poor wetting on substrates such as polyethylene, limiting their development. Alcohol-soluble polyurethane ink uses more environmentally friendly alcohol solvents, making it a new and eco-friendly ink. It avoids the high toxicity of traditional solvent-based polyurethane binders and the slow evaporation and high energy consumption of water-based polyurethane binders. It is now widely used in plastic flexible packaging and gravure printing industries.
