Anionic colouration of acrylic fibre. Part II: Printing with reactive, acid and direct dyes

Modified acrylic fibre was obtained and printed with vinyl sulphone (CI Reactive Blue 238), chlorotriazine (CI Reactive Red 24), α-bromoacrylamide (CI Reactive Red 84), CI Acid Green 25 and CI Direct Blue 78. Two thickening agents namely sodium alginate and Meypro gum were used in the printing paste formulation. Compared with the prints obtained from modified acrylics, those of blank samples appeared almost colourless. Atmospheric steaming at 100 °C for 20–30 min achieved the fixation of the prints and the maximum colour strength was obtained at pH 4–5. The fixation of the dye molecules with the modified acrylic fibres was investigated to show mainly ionic and covalent bonds for the case of reactive dyes, whereas for acid and direct dyes it was mainly due to ionic bonds. The colour strength and the extent of dye fixation of the prints obtained using sodium alginate as the thickening agent was generally better than those obtained using Meypro gum. The prints displayed excellent to good fastness properties.