The stability of disperse red/reactive-red dye inks

Abstract

CI disperse red 896 was used as a representative disperse red dye to investigate the stability of inkjet printing colour paste. Various additives were added to the dye in different mass fractions to study the thermal stability and freeze–thaw stability of the ink in terms of average particle size, viscosity, and surface tension. The centrifugal stability of the colour paste and ink was characterised by their specific absorbance. When grinding the colour paste, use of a defoamer can improve the grinding efficiency, without affecting the stability of the paste. The most stable ink prepared from the colour paste contained 20–35 wt% paste. Ethylene glycol and glycerol were combined and their amounts controlled respectively at 6–14 wt%. The triethanolamine content was <1 wt% when the fatty alcohol polyoxyethylene ether content was 0.2 wt%. The sodium dodecyl sulphate content should be less than 0.15 wt%, and that of polyvinylpyrrolidone-K30 should be <0.7 wt%.