Thermodynamic Behavior on the Binding of the Polymers and Acid Dyes in Inkjet Ink for Textiles

摘要

To formulate inkjet ink for textiles,not only dyes or pigments but also additives are needed and the types and amounts of additives are the most important factors. In the present study,the interaction between the three acid dyes (C. I. Acid Red 88,13,and 27) and additives such as water-soluble polymer,poly (vinylpyrrolidone) (PVP),were investigated. To elucidate the effects of the additives,the binding constants of the dyes with the polymers,Kbind,the visible absorption spectra of aqueous dye solutions in the absence and presence of PVP were measured at 15,25,35 and 45℃. To discuss the thermodynamic behavior on the binding of the polymers and the dyes,the thermodynamic parameters △Hbind and ⊿Sbind,were estimated. The binding constants,Kbind,of the acid dyes with PVP were dependent on the dye structure and the molecular weight of PVP. The ⊿Hbind values for all the dyes were negative,showing that the binding processes are exothermic. The absolute values of ⊿Hbind decreased in the order of R-1 > R-2 > R-3,which is comparable to the order of the number of sulfonate groups. The increase of PVP molecular weight made the thermodynamic process to be less enthalpic and more entropic.