PREPARATION AND CHARACTERIZATION OF WATER BASED INK FOR FLEXIBLE PACKAGING PRINTING APPLICATIONS

Abstract

Printing ink plays an essential role in the packaging area, and the demand for printing inks is increasing day by day all over the world. Due to the presence of volatile organic compounds (VOCs) in solvent-based inks, water-based ink has received considesrable interest in the ink industry due to sustainable and environment-friendly printing materials. Therefore, a study aimed to develop a new waterborne acrylic copolymer resin (acrylic-co-resin) was synthesized for the development of water-based printing inks on polyethylene terephthalate (PET) film. The synthesized acrylic resin showed good water solubility, high acid value (120 mg KOH/g), and about 57% solid content. The developed water-based inks (cyan, magenta, and yellow) exhibited small particle size (<1μm) and optimum surface energy within required values (31.5, 32, and 30mN/m) for good adhesion of ink upon PET films. The developed inks also showed good storage stability over 30 days. Further, to evaluate the application performance, the inks were printed on corona-treated PET films at room temperature, and the ink drying time was measured. Additionally, the inks were printed on corona-treated PET film to evaluate the application performance. The developed inks showed a short drying time (7-9 sec), which indicates their fast-drying nature. Moreover, the developed inks showed good printability, color strength, high adhesion, and excellent rub-resistant properties. Thus, the overall results demonstrated the potential of water-based inks in printing applications. Further, another study planned to use water-based ink, cellulose nanocrystals (CNCs) incorporated acrylic-co-polymer resin (Ac-co-res/CNC) was synthesized to improve water-borne ink printing properties. The CNCs were incorporated into the acrylic-co-polymers (Ac-co-res) to enhance the physicochemical properties of Ac-co-res. The Ac-co-res was synthesized by free radical polymerization using different acrylic monomers. The three water-borne inks (cyan, magenta, and yellow) were prepared using Ac-co-res and Ac-co-res/CNC and subsequently printed on corona-treated PET films. The inks having Ac-co-res/CNC showed significant enhancement in drying rate, adhesion, and gloss. After adding CNCs, the drying time decreased from 9s to 7s, adhesion increased by 2%, and the gloss was increased from 20-48%, compared to inks prepared with Ac-co-resin. The highest gloss increment was in case of magenta and lowest was in yellow color ink. Thus, the overall results revealed that the Ac-co-res/CNC showed excellent potential in developing water-borne inks in the flexible printing application.