DIFFUSION OF ACID DYES IN NYLON 6 FILM DYED BY THE FOAM DYEING METHOD

Abstract

Authors have developed a laboratory scale foam dyeing apparatus in which textiles are dyed in foams with blow ratio of 200-300. Diffusion of purified acid dyes (C. I. Acid Red 134 and Green 25) in nylon 6 film from the foam phase was studied by this apparatus with the cylindrical film-roll method. The concentration-distance profiles of the acid dyes in nylon 6 film were analyzed in terms of contribution of ionic sorption (Langmuir type sorption) and non-ionic one (Henry's dissolution). The profiles were compared with these determined by the diffusion from bulk solution, particularly with respect to the contributions of non-ionic sorption and ionic one.
The results were:
1) Diffusion of C. I. Acid Red 134 (dibasic dye with large hydrophobic moiety) in nylon 6 film in the foam dyeing is characterized by smaller contribution of the non-ionic sorption than that in ordinary dip dyeing even if “overdyeing” occurs. The non-ionically absorbed dye on the film bleeded easily in water.
2) Both increase in surfactant concentration and decrease in dye concentration affected non-ionic sorption even in foam dyeing; therefore, interaction between dye and surfactant in foam film is similar to that in bulk liquid.
3) There was only a slight difference between the diffusion behavior of C. I. Acid Green 25 (dibasic dye with moderate hydrophobic moiety) in nylon 6 film in the foam dyeing and that in the dip dyeing.