Factors influencing polymeric granule-assisted dispersion of ultraviolet ink

The objective of this research is to identify and evaluate the factors influencing polymeric granuleassisted dispersion of ultraviolet (UV) ink particles. First time, granule-assisted alternative dispersion was observed during adsorption deinking. By optimizing and combining this alternative dispersion process with pulping, we aim to minimize the energy consumption in the dispersion process and thus reduce the environmental impact of the paper recycling process on carbon footprint. For experimental confirmation, a combination of printed paper and polymeric granules was selected such that ink detached from the fibers would not be adsorbed onto the surface of polymeric granules. Factors that affect the mechanical dispersion process were chosen and varied for optimization of the newly developed dispersion method. Results show that at 15% consistency, temperature 45°C, and mass ratio of oven dry pulp and granules of 1:1.5 (200 g pulp and 300 g granules), the granule-assisted dispersion process gives optimum results for reduction of specks size. All experiments were carried out at rotor speed 2 of Hobart pulper (INGEDE Method 11 “Assessment of print product recyclability–Deinkability test”). These optimized parameters are similar to the optimized parameters of adsorption deinking, which give a further option to combine both of the steps (adsorption deinking and granule assisted dispersion) into one. We also demonstrated that the polymeric granule-assisted dispersion method is a viable replacement for the conventional dispersion process by assuring no alteration in fiber length, water retention value of pulp, and strength properties of the handsheets.