Synthesis and application to cellulose of reactive dye precursor of anti-bacterial N-halamine

To achieve textile dyeing and functional finishing in one process, a bleach-resistant reactive dye precursor to anti-bacterial N-halamine was synthesised by reacting a type of dichlorotriazine reactive dye with 4-amino-2,2,6,6-tetramethylpiperidine. The synthesised compound, which can be transformed to an N-halamine molecule by exposure to dilute bleach solution, was used to dye cotton fabrics. After exposure to a dilute sodium hypochlorite solution, dyed cotton fabrics showed excellent anti-bacterial properties against Staphylococcus aureus and Escherichia coli O157:H7, facilitating a ca. 6-log reduction in bacteria within a short period of contact. Compared with the dichlorotriazine reactive dye, the reactive dye precursor demonstrated comparable dyeing properties including exhaustion and fixation values. No differences in rub fastness, wash fastness or bleach fastness were detected between fabrics dyed with, respectively, dichlorotriazine reactive dye and the reactive dye precursor to N-halamine.