Application of heterobifunctional reactive dyes on silk

Abstract

The behaviour of heterobifunctional reactive dyes, containing a monochlorotriazine and a vinyl sulphone group, on silk has been investigated. Maximum exhaustion and fixation were obtained in a neutral medium at 90d̀ C. The addition of sodium sulphate was found to promote the exhaustion of reactive dyes at pH values above the isoelectric point of silk. A reduction in the solubility of dyed silk indicated that crosslinks were formed with bifunctional reactive dyes.

Dyeing and finishing of lyocell union fabrics: an industrial study

“…This was also observed in a similar study on silk/viscose union fabrics [14]. The reactive dyeing of silk has been studied extensively [20] and the results of these studies show that exhaustion and fixation of reactive dyes takes place best under neutral conditions. Under alkaline conditions, the reactive dye uptake on silk is low as compared with the neutral medium.…”

“…For lyocell/silk fabrics, although the silk was dyed with acid dyes so that the dyeing sites were occupied, there was probably some amount of acid dye desorption, and those dyeing sites were occupied by the reactive dyes, which gives rise to the staining effect. Although maximum exhaustion and fixation with reactive dyes on silk takes place under neutral conditions [20], the presence of electrolytes in alkaline conditions does result in dye fixation.…”

Dyeing of silk with bifunctional reactive dyes: the relationship between exhaustion and fixation

“…Complete hydrolysis in alkaline media renders both vinyl sulphone and monochlorotriazine groups inactive, while the former can specifically be inactivated by reaction with either sodium sulphite [3] or sodium bisulphite [4] in alkali. Sodium bisulphite is a fairly strong nucleophile and can react with the reactive dyes.…”

“…Work on the use of solvents for improved dyeing of wool and acrylic fibres has been reported [4,5]. Improved dyeability is achieved through the swelling and or plasticising action of the solvents, either by opening up the fibre s t r u m or by making the chain molecules highly mobile at the dyeing temperature [3].…”

Influence of Eri silk fibre on the physical characteristics and dyeing properties of Eri silk/cotton blended yarn

“…Bleaching of Eri silk was studied using H 2 O 2 but, for the blended yarn of Eri silk and other fibres, an optimal bleaching method should be studied. Moreover, there have also been a few papers published regarding the relationship of the structure and dyeing properties of silk fibres after dyeing with acid dyes [9,11,12] or reactive dyes [13,14]. To our knowledge, no article has been reported about the dyeing properties of the blends of wild silk with cotton.…”