Dye-Fiber Bond Stabilities of Some Reactive Dyes with Wool

Abstract

Wool was dyed with seven reactive dyes having the same chromophoric group (1-amino-4-anilino-anthraquinone-2-sulfonic acid) but different reactive groups and then thoroughly extracted so that all noncovalently bound dye was removed. The wool was treated with buffer solutions in the pH range of 1.6-10.6 at 70°C. The hydrolysis rate of the dye-fiber bonds was estimated by colorimetric measurement of the buffer solution.Reactive dyes containing the α-bromoacrylamide or the difluoromonochloropyrimidyl system gave the highest fixation on wool, whereas those containing a mono-or di-chloro-s-triazine, trichloropyrimidine, or vinylsulfone group gave lower values. Poor fixation was obtained with the β-hydroxyethylsulfone sulfuric acid ester and the β-hydroxyethylsulfonamide reactive group. Since only 2-10% dye-fiber bond hydrolysis was observed after 24 hr at 70°C, it must be concluded that the dye-fiber bond stability of all the reactive groups now available is sufficient for wool dyeing. The washfastness of reactively dyed wool is, therefore, not dependent on the nature or stability of the dye-fiber bond but on the fixation ratio, (i.e., the fraction of covalently bonded dye relative to all dye on the fiber) obtained during dyeing.

Dyeing method and properties of polymaleic acid dyes on cotton

“…If only physical adsorption occurred between the dyes and cotton, the dyes could easily be washed away through colour stripping. However, if chemical bonds were formed, the dyes could not be stripped from the fibres . Results given in Figure show that, for dyeing with a curing process, the reduction in K / S was less than 5% for DMF stripping at 100 °C, and hardly any colour was stripped off for water at 90 °C even in a 4 h period.…”

Dye‐Fibre Bond Stabilities of Some Reactive Dyes on Silk

“…For dyeings with dyes 1, 2, 3,4, 5, 7,8, 10 and 11, buffer solutions were prepared as described previously [4,10,121.…”

Fixation Processes in Dyeing

“…A range of Verofut (BAY) dyes for wool which make use of 5-chloro-2,4-difluoropyrimidine as the reactive group has been described [25] ; the bromoacrylamido reactive Lanasol (CGY) dyes, from which bromine is released during dyeing in proportion to the degree of furation on the fibre, have been described by Mausezahl [27] who has also tabulated the reactive-dye structures used in the dyeing of wool to date. Zollinger et al [28] have studied the stabilities of bonds between wool and seven different reactive groups attached to identical chromogens. By extraction of the non-covalently bonded dye from.…”