Study On The Dyeing Of Terylene Fabric With Disperse Red 54 In Supercritical CO₂ With Or Without Cosolvent

Compared with traditional dyeing process, as an innovative and"green"technology, supercritical carbon dioxide dyeing has many advantages such as less dyeing time, good dyeing effect and less pollution. Dye solubilities in supercritical carbon dioxide are important to the dye uptake on the fabric and the addition of cosolvent in the supercritical carbon dioxide can improve the dyeing effect. A flow-type dyeing apparatus was employed to dye terylene fabric with disperse red 54 in supercritical carbon dioxide with and without ethanol or water as cosolvent at temperature rage from 70 to 120℃and pressure from 14 to 24 MPa.The results revealed that dyeing for 60 min can ensure the dyeing equilibrium on the terylene fabric. In pure supercritical carbon dioxide dyeing system, the dye uptake increased with temperature and pressure, the maximum uptake appeared at 22 MPa when the temperature was high, but the changes in dye uptake were not obvious with pressure when the temperature was relatively low.The dye uptake was found significantly affected by the cosolvent. The addition of cosolvent would greatly enhance the dye uptake at low temperature and ethanol was more effective than water. The cosolvent effect on dye uptake decreased with increasing temperature. When the temperature was relatively high, adding ethanol would't help to increase the dye uptake. Moreover adding water would even lead to a decrease in dye uptake at the same condition.The partition coefficients of disperse red 54 between the fabric and supercritical carbon dioxide rose with the increase of temperature or pressure and also increased with the addition of cosolvent at low temperature. But the presence of cosolvent favours the dye partition towards the fluid phase and lead to the big decrease of the partition coefficients at higher temperature.The"film roll method"was used to study the behavior of dye permeating terylene fabric in supercritical carbon dioxide with and without cosolvent. The homogenous reaction and diffusion model was employed to study the dye duffusion in the terylene fabric. The results indicated that the dyeing and diffusion rate of dye both increased with increasing temperature and the increase of dyeing rate was bigger than that of diffusion rate, which led to a week diffusion in the fabric.The diffusion was effectively enhanced by the presence of cosolvent.