Process for dyeing cellulosic fiber materials with vat dyes: dosing continuously over time interval
AssigneeCiba-Geigy Corporation
InventorPeter J. Horn
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Abstract
There is disclosed a process for dyeing cellulosic fibre materials with vat dyes, which comprises adding to the dyebath all or some of the auxiliary chemicals required for the dyeing process, and subsequently, after a pretratment time, adding the vat dye or its leuco form with the aid of a metering device to the dyebath, and dyeing the fiber materials by optionally increasing the temperature of the dyebath. Level dyeings are obtained with the novel process, the cellulosic material having a perfectly level appearance as well as good light- and wetfastness properties.
Claims9
A process for dyeing cellulosic fiber materials with a vat dye, which comprises
- adding to a dyeing bath all or some of the alkaline compounds or alkali donors and reducing agents, and further auxiliary chemicals, required for the dyeing process,
- pretreating the fiber material at temperatures of 20.degree. to 100.degree. C. in said dyeing bath,
- subsequently adding the vat dye or its leuco compound continuously over an interval of time to the dyeing bath at temperatures of 20.degree. to 100.degree. C., and
- thereafter dyeing the fiber material at temperatures of 20.degree. to 110.degree. C.
Dependencies are inferred from the claim text.