Details:
Summary:
Many printing inks use volatile solvents in the formulation, which are hazardous to the environment from emission of VOC's and at the same time, synthetic resins in these inks are not biodegradable. These problems and particularly the volatile price of petroleum are main reasons to look for new resources for making more environmentally friendly printing inks. The majority of the commercially available water-based inks are formulated based on using acrylic resins, synthetic colorants, solvents/water and additives, which are the common main components for formulating printing inks. Soybean protein is a potential renewable raw material for replacement of acrylic resins. In this research, soy proteins were tested for their suitability to partially or fully replace acrylic emulsion resins in water-based packaging inks. The focus was on formulating inks for linerboards, because linerboard is a substrate printed with 100% water-based ink formulations, and the linerboard packaging sector is growing rapidly. The first step was formulating water-based ink based on fully acrylic solution and emulsion polymers as resins. Next, the letdown portion of the ink was formulated with soy polymers, adding them in increments 10-20-30 up to 100% replacement of acrylic emulsion portion of fluid packaging ink. A blue ink was formulated, and its printability, rheology, and end use properties such as rub resistance, gloss, and adhesion were tested and compared to fully acrylic formulations. It was found that the soy polymer did not affect the final color of packaging ink, measured as delta E. DE for all soy formulations was less than 1.0, when fully acrylic formulation was used as a standard. Selected end use properties of soy inks were similar to fully acrylic formulations. This research will help to achieve the formulation of a truly environmentally friendly water-based ink, while eliminating emission of VOCs.