Study on the Water Resistance of Polyurethane Water-Based Ink

Being crucial to its using performance, water-resistance of the ink refers to the water-resistance performance of the pigment used in the ink. Lack of water-resistance may cause many problems, such as loss of gloss due to emulsification and blurring areas on the printed pages. Meanwhile, there will be no transfer of the ink to the substrate when printing. In this paper, the polyurethane resin is used to replace the traditional resin as binder in the experiment and the water-resistance performance of polyurethane water-based ink (PWBI) is also studied. It is shown that the water resistance performance of PWBI is directly affected by the dispersion of the pigment, the pH value and the viscosity of the ink. Constructive conclusions are reached as follows: (I) when the pH value of PWBI ranges between 8.5 and 9.5, the resin of binder has a good dispersion and the wettability of the pigment is also enhanced, resulting in the uniform ink film and better water-resistance; (2) The system becomes stable when the pigment particles disperse evenly. Therefore, the uniformity, continuity,density as well as the film quality and water resistance of the membrane formed after printing can be improved; (3) Inappropriate viscosity will lead to uneven distribution of the ink on the substrate, which affects the quality and water-resistance of the film.