Scratch-resistant Water-based Varnish Developed

As the strengthening of people's environmental awareness and environmental protection requirements and constraints of package printing and commercial printing, such pollution-free "green" materials water-based varnish has rapidly developed and becomes the research emphasis in the field of overprint varnish. So far, water-based varnish's scratch-resistance is not as good as solvent-based varnish or UV varnish, which restricts water-based varnish used in some field. In this paper, according to the research status in domestic and foreign of water-based varnish, used for color printing paper water-based varnish with high scratch-resistance was prepared.The paper was studied that water-based varnish's viscosity, adhesion, glossiness, wear-resistance and scratch-resistance was influenced by the type and dosage of the important components of water-based varnish, such as resin and auxiliary. Formula test design principle was used to design water-based varnish's formulation to determine the best ratio of the mixed resin to optimize the best water-based varnish formulation and then prepared water-based varnish with well scratch-resistance.The results show that the resin, pH and water content were the main factors to affect the viscosity of water-based varnish. The viscosity of water-based varnish is high when high viscosity resins are used to prepare the water-based varnish. If the system's pH is bigger, the water-based varnish will be higher. When the system's pH maintained between 8.0 and 9.5, water-based varnish's performance is best. The adhesion of water-based varnish mainly depends on the used resin. Adding appropriate amount of adhesion promoter can improve adhesion of water-based varnish. Resin determines the water-based varnish coating's scratch-resistance and wear-resistance. Adding appropriate amount of wax emulsion can improve scratch-resistance and wear-resistance to some extent. Adding wax emulsion and flow agent has a great influence on leveling performance. Resin and wax emulsion are the main factors to affect the glossiness. By adding the appropriate amount of flow agent glossiness can be improved to some extent.