Insights into Influences of Dye Hydrophobicity on Cleanliness and Resolution of Fabric Ink-Jet Printing

Abstract

Fabric ink-jet printing is a crucial technology of clean production in the textile industry. Reactive dyes and organic solvents are the important component of ink-jet printing ink. The structure, hydrophobicity, and aggregation degree of reactive dye affect the amount of organic solvent and ink droplets spread on fabric, which is essential for reducing organic solvent dosage and obtaining high quality ink-jet printing images on fabric. In this study, two red reactive dyes (reactive red 218 dye and reactive red 24:1) with different structures were used to prepare reactive dye solutions, which were subsequently explored by investigating the surface tension, rheological properties, visible absorption spectra, and droplet formation and observing the spreading behavior on cotton fabrics. For the first time, the effects of dye hydrophobicity on organic solvent dosage and ink-jet image resolution were studied. The results showed that reactive red 218 dyes possessed stronger hydrophobicity and more compact aggregation. Reactive red 218 clusters were more easily disaggregated into dye monomers through the hydrophobic interaction between the DEG and dye molecules, while reactive red 24:1 clusters were disaggregated into small clusters. Reactive red 218 solution droplets were more stable, which could reduce the air pollution caused by the satellite droplets. Based on the above reasons, the solution of dye with stronger hydrophobicity required less organic solvent and had a smaller droplet spread area (represents higher printing resolution) on the fabric. These findings provided a novel direction for reducing organic solvent consumption and improving the utilization rate of dye solution.