Study on Diffusion of Disperse Red 54 within Terylene Fabric in Supercritical Carbon Dioxide

Supercritical CO2 dyeing is a green dyeing process, while the diffusion of disperse dyes in terylene fabric is one of the most important factors in this technology. In order to study the diffusion of disperse dyes in terylene fabric in the presence of supercritical CO2, diffusion experiments was carried out using the film roll method in a flow-type dyeing apparatus under 70~110 ℃ and 16~24 MPa. The results indicate that the terylene fabric is dyed immediately and a widely-used model for dye diffusion immerged in water or supercritical CO2 is not suitable to describe the dye diffusion in terylene fabric. A homogenous reaction and diffusion model was successfully employed to analyse the diffusion process. It is found that the ratio of dyeing rate and diffusion coefficient increases with temperature, but when the pressure increases, the ratio of dyeing rate increases in the beginning and then decreases.