Crosslinking a hydroxyethylsulphonyl dye on cotton to achieve covalent fixation in a long-liquor process

A heterobifunctional dichlorotriazine and vinylsulphone (DCT-VS)] reactive crosslinker, 2,4-dichloro-6-{ρ-(2'-sulphatoethyl)sulphonyl]phenylamino}-1,3,5-triazine (DC-SES) was synthesised and coapplied with nicotinic acid to covalently fix hydrolysed Cl Reactive Black 5 (HBB) (hydroxyethylsulphonyl dye) to cotton in a long-liquor process. It is suggested that a very active quaternised nicotinic acid ammonium salt of DC-SES was generated in situ , which reacts readily with HBB and cellulose leading to dye fixation. Further dye fixation can be obtained by the addition of alkali at 60 °C; the final fixation value from this system is very good. Application of this system as an aftertreatment in the conventional Cl Reactive Black 5 dyeing bath, results in 10–15% higher exhaustion and fixation values compared to the usual dyeing procedure.