Water is used as a solvent in many textile production processes, such as dyeing, rinsing, washing and functional finishing, making the textile industry a major contributor to water crises and water pollution. To help reduce water consumption and contamination for the textile industry, ITRI introduced a single-bath supercritical fluid dyeing (SFD) process for PET or blended elastic textiles. The Functional Dyeing Synchronized with CO2 Supercritical Technology uses supercritical carbon dioxide as dyeing solvent instead of water, thereby eliminating water consumption and pollution. Without any water usage, it also optimizes textile manufacturing since textiles no longer need the time to dry.
Mechanism of the Functional Dyeing Synchronized with CO2 Supercritical Technology.
The Functional Dyeing Synchronized with CO2 Supercritical Technology is focused on the development of high-fastness supercritical fluid dyestuff for PET or blended elastic fibers. ITRI created a dye structure design platform that optimizes the molecular structure of chromophore and auxochrome, increasing its affinity with spandex fibers and achieving higher dyeing fastness. A functional finishing agent is developed to complete the single-bath SFD process. Moreover, through proportional regulation of CO2-philic/hydrophilic segment ratio, the wicking property compares favorably with the Dry-Fit function. The molecular design follows the bluesign® regulations, where dyeing and functional finishing process may be integrated to omit the follow-up water-bath functional finishing, thereby saving 15% of water as compared to current SFD manufacturing procedures.
Comparison between ITRI’s dyeing technology and normal SFD.
ITRI’s technology allows for a wider color range, high dyeing fastness (≧ level 3.5 according to AATCC standards), and brighter shades. It has developed different types of dyes, and its performance in lab, and pilot production scale all demonstrate promising outcomes that may impact the global textile industry. Functional Dyeing Synchronized with CO2 Supercritical Technology is suitable for use in producing sportswear textiles such as Spandex fiber, which is difficult to color due to its PU-based molecular structure. With the design of “Spandex-like” multi-colored dyestuff, the affinity between supercritical fluid dyestuff and Spandex molecules is effectively enhanced. Undergoing AATCC standard test method for colorfastness to washing, the result indicated that ITRI’s dye did not come off during washing and the fastness towards perspiration and crocking achieves level 4 and above.
Functional Dyeing Synchronized with CO2 Supercritical Technology is a water-saving and pollution-free technology used in SFD functional dyeing and finishing, which can replace water with carbon dioxide while simplifying manufacturing procedures. The technology can help Taiwan’s dyeing and finishing industry to save 2.5 million tons of water resource usage per year and to move toward the goal of Zero Discharge of Hazardous Chemicals (ZDHC) by 2020. It also solves the problem that there is still no SFD auxiliary for functional textile with the demand for the moisture absorbing feature, and allows one-time completion for dyeing and functional finishing without the use of water. With this technology, the textile industry is able to produce eco-friendly and high quality functional fabrics.