Cationic dyes are special dyes for polyacrylonitrile fibers. Cationic dyes usually use zinc chloride to precipitate and precipitate double salts in the manufacturing process. The content of zinc in commercial products is very high, generally 15% to 20%. ETAD clearly stipulates that zinc is one of the heavy metals to be controlled in dyes. Therefore, the development of environmentally friendly cationic dyes is mainly caused by zinc in dyes. Through technological transformation, the new manufacturing technology no longer uses zinc chloride, but instead uses other environmentally and ecologically harmful precipitants, so that the cationic dyes produced meet environmentally friendly dye requirements, such as Viocryl Red GRLS from D&G Dyes, UK. ZF 200%, Viocryl Navy FBL ZF, Viocryl Black FL ZF 200%, etc. are all zinc-free cationic dyes.
Problems with environmentally friendly dyes There are many misconceptions among manufacturers, especially dye users, that azo dyes are not environmentally friendly dyes. This is actually not the case. Instead, azo dyes containing 22 dye intermediates that have carcinogenic components or cleave carcinogenic substances are non-environmentally friendly dyes.