Development of high-performance, chemical pretreatment-free dye-based inks for digital printing on polyester fabric

An innovative thermal-sensitive ink has been developed and thoroughly tested on polyester fabric. Unlike conventional methods, this new ink eliminates the need for chemical pretreatment and post-printing washing of the fabric before or after printing. It utilizes high-temperature disperse dyes and a biodegradable carrier molecule called a triblock copolymer, specifically Poly(ε-caprolactone-lactic acid)-poly(ethylene glycol)-poly(ε-caprolactone-lactic acid) (PCLA-PEG-PCLA). This remarkable copolymer comprises dihydroxy polyethylene glycol (PEG), ε-caprolactone (CL), and L‐lactide (LA). Upon contact with a heated surface, such as a fiber or textile, the ink droplets swiftly transition rapidly, transforming into a gel-like state. This transition enhances the ink's viscosity, effectively preventing undesired spreading and resulting in precise edge definition on the fabric. To comprehensively evaluate the performance of polyester fabric printed with this innovative ink, a series of meticulous evaluations have been conducted. These evaluations encompass pH levels, particle size, surface tension, viscosity, ink droplet formation, as well as real-time photo-rheological and LF‐NMR analyses conducted on the surface of the polyester fabric. The newly developed inks demonstrate exceptional effectiveness and are highly suitable for digital printing applications across various materials. Furthermore, the implementation of this new ink can significantly reduce the reliance on chemicals and minimize wastewater production during the manufacturing process.