Rapid and environmental-friendly continuous gel-dyeing of polyacrylonitrile fiber with cationic dyes

A novel and environmental-friendly continuous gel-dyeing technique for polyacrylonitrile (PAN) fiber was designed and developed. The gel-dyeing was carried out at the gel stage during PAN fiber production. The dyeing process can be completed in 20 s under a low temperature of 50 degrees C without a large amount of water. After the dyeing, the dyed gel fiber was further drawn and crystallized. The cationic dye molecules were trapped inside the fibers. All three cationic dyes used could obtain excellent dye uptake and color yields with Integ values over 50 after dyeing for 20 s at 50 degrees C. The obtained color was uniform. All fastness of the samples, including fastness to rubbing, fastness to washing (60 degrees C) and fastness to perspiration, reached 4-5 grade. Compared with traditional dyeing techniques, the new continuous geldyeing technique is obviously much faster, more efficient and eco-friendly. This dyeing method greatly saves water, energy and time. It is of great significance to the clean production of the dyeing process of PAN fibers. (c) 2020 Elsevier Ltd. All rights reserved.