Pigment Red 48:4

Enzymatic Deinking for Flexographic Printing Inks Such as Pigment Red 48:4

Fillat, Ursula, et al. Chemical Engineering Journal, 2015, 260, 486-491.

This study assessed the effectiveness of a biotechnological method utilizing a laccase-mediator system for the biodeinking of three flexographic inks-Blue 1, Magenta HX-E, and Pigment Red 48:4-across various types of pulps, including bleached pulp, deinked paper pulp from secondary fibers, and pulp from commercial uncoated and coated office paper.
Two fungal laccases were employed as catalysts: one derived from the basidiomycete Coriolopsis rigida and the other from the ascomycete Myceliophthora thermophila. These were paired with either HBT (1-hydroxybenzotriazole) or methyl syringate, representing synthetic and natural mediators, respectively. The decoloration rates were notably higher for Blue 1 and Magenta HX-E compared to Red 48:4, with optimal results achieved using bleached pulps without any additives.
Additionally, the study investigated the impact of various additives on ink decoloration and enzyme activity to identify compounds that may inhibit enzymatic biodeinking. It was found that calcium carbonate significantly impeded laccase biodeinking, reducing ink decolorization by up to 40%. This highlighted the differences among the pulps examined and suggested that the presence of mineral fillers in older paper can hinder the biodeinking process.