Process for dyeing polyamides using controlled addition of dye

摘要

The invention relates to a process for the dyeing of a fibre article which contains polyamide polymer fibres with an anionic dye and dyed products manufactured using this process. The process includes immersion of the article in a dyeing bath of liquid solvent for the anionic dye. The liquid solvent and the article are heated to a temperature at least equal to the transition temperature for dyeing the polyamide polymer fibre. The anionic dye is added to the dyeing bath in the form of a miscible liquid concentrate at a rate of dye addition during the period of controlled dye addition. At least part of the dye is added when the solvent and the article are at a temperature equal to at least the dyeing transition temperature. Stirring of the bath during the time for which dye is added and when the solvent and article are at a temperature equal to at least the dyeing transition temperature is brought about by mixing the dye concentrate with the solvent in the bath to form a dilute dye solution and providing a flow of dilute dye solution in relation to the article to cause the dye to be transported in relation to the article. The stirring also causes essentially uniform transport of the anionic dye to the article in the medium. The rate of addition of the dye is adjusted at least when the solvent and the article are at a temperature equal to at least the dyeing transition temperature so that the rate of addition of the dye constitutes the primary control over the rate of absorption of the dye by the article.