Effect of reactive dyes upon the uptake and antibacterial action of poly(hexamethylene biguanide) on cotton. Part 1: Effect of bis(monochlorotriazinyl) dyes

Poly(hexamethylene biguanide) (PHMB) is of interest as a bactericide for fabrics. It has affinity for cotton by reaction with the cellulosic carboxylate groups. In this study, the capacity of undyed cotton to absorb PHMB has been determined and compared with cotton dyed with anionic bis(monochlorotriazinyl) reactive dyes. When cotton is dyed with these dyes the absorption of PHMB increases, the dye providing sulphonic acid sites with which the PHMB can react. The reacted PHMB and the percentage fixation of reactive dye were determined and from this the concentration of sulphonic acid on the dyed fibre. In the case of cotton dyed with Procion Yellow H‐E4R, the dye increased the absorption of PHMB to approximately 1.45 mequiv. of biguanide per sulphonic acid group. For Procion Red H‐E3B and Navy H‐ER the figures were 1.18 and 1.00, respectively.