Hoechst Aktiengesellschaft

Karl-Heinz Rostermundt

Hans-Ulrich Von Der Eltz

Klaus Turschmann

Joachim W Lehmann

Trichromatic dyeings with acid dyes which exhaust from strongly acidic liquors have weaknesses with respect to wet fastness, which are due to insufficiently fast components (blue, red). It has been found, according to the invention, that by replacing the insufficiently fast acid dyes by reactive dyes of the vinylsulfonyl type and retaining the method of dyeing under strongly acidic conditions the wet fastness level of the exhaust dyeings can be improved while the levelness obtained remains as good.

Process for dyeing wool

The dyeing of wool with reactive dyes in a strongly acid medium (containing sulfuric acid) requires no longer acceptable, long heating-up times (50-60 minutes) in order to obtain level dyeings. It has now been found, according to the invention, that by rapidly heating up the dyebath which contains the dyes of the vinylsulfonyl type and also all the ingredients, except the acid, to the dyeing temperature together with the material to be dyed and then metering in the sulfuric acid under isothermal conditions at the dyeing temperature it is possible to obtain very level and very fast dyeings in a significantly shorter overall dyeing time. Carbonized wool can be dyed without prior neutralization.

Isothermal rapid-dyeing process for wool with vinyl sulfone type

The level dyeing of wool with reactive dyes and simultaneous endeavors to shorten the dyeing process appear to be incompatible. It has now been found, according to the invention, that in the course of the exhaustion process it is possible through metered addition of the acid required for fixation over a prolonged period to the dyebath which is already at the dyeing temperature and contains no acidic fixing agent to obtain a shortening in the total treatment time while at the same time safeguarding the levelness of the dyeings.

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Eschborn, Germany

Karl-Heinz Rostermundt