Comparative Analysis of Anthraquinone Reactive Dyes with Direct Dyes for Papermaking Applicability

Aiming to compare the applicability and the successfulness of reactive dye printing papers’ coloration, two laboratory-synthesized anthraquinone reactive dyes are studied in comparison with two commercially available anionic and cationic direct dyes. Reactive dye 1 is monochlorotriazine and reactive dye 2 is bifunctional (contains two reactive groups—one is a monochlorotriazine atom and one an unsaturated allylic group). The synthesized reactive dyes are investigated through a paper slurry, white waters and paper sample properties comparative analysis. The drainage ability, flocculation volume and sedimentation index of paper slurries are determined. The turbidity, conductivity, pH and dye concentration in the white waters are also examined to ensure dye fixation. Through SEM, the paper structure is evaluated. The strength properties, colorimetric characteristics and stability at accelerated light aging of all 15 paper samples are investigated. The dewatering ability is enhanced, the white waters are clarified, the conductivity and pH level are stable and the dye concentration is on the same levels as for the direct dyes. The paper structure is uniform, the strength is slightly enhanced and color differences are indistinguishable compared to those of the direct dyes, when the ratio of the fixing agent to dye is appropriately optimized.