Ciba-geigy Corporation

Josef Navratil

Heinz Abel

A process is described for dyeing hydrophobic fibre material with unfinished disperse dyes from an aqueous liquor, which comprises dissolving one or more such dyes in water at a temperature of 50.degree. to 150.degree. C. by means of a surfactant or surfactant mixture with a hydrotroping or solubilizing action on disperse dyes, bringing the dye solution together with the substrate in a dyeing apparatus, then heating the dyeing liquor to the dyeing temperature and completing the dyeing at that temperature and then removing the substrate and restoring the exhausted dyeing liquor to the original composition by adding water, surfactant and dye and using it again for dyeing.

Process for dyeing hydrophobic fibre material from aqueous bath

The invention relates to a process for dyeing hydrophobic fibre material under HT conditions with unformulated disperse dyes from an aqueous liquor, which process comprises dissolving one or more such dyes in water, in the temperature range from 70.degree. to 100.degree. C., with a surfactant or mixture of surfactants which has a hydrotropic action on disperse dyes, feeding the dye solution into a dyeing apparatus which contains water heated to 70.degree. to 100.degree. C. and substrate, and subsequently heating the dye liquor to dyeing temperature, or dissolving the dye at a temperature of over 100.degree. C. under pressure by means of the surfactant or mixture of surfactants which has a hydrotropic action on the dye, feeding the solution into a closed dyeing apparatus which contains water heated to 100.degree. to 150.degree. C. and substrate, and, in both cases, carrying out dyeing in the temperature range from 120.degree. to 150.degree. C. with constant circulation of the dye liquor. The advantage of this process is that disperse dyes can be used direct for dyeing e.g. polyester without complicated grinding and formulation procedures.

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Basel, Switzerland

Josef Navratil