Hoechst Aktiengesellschaft

Bernd Durl

Sienling Ong

Kurt Brozat

Johannes Bos

Wolfgang Richter

Peter Raffel

In the conventional discharge printing on polyamide fiber materials using acid dyes, above all, the very low wet and light fastness properties of the designs obtained in this manner are frequently an obstacle to the wide expansion of this interesting technique in practice. Applying this known patterning method for wool or nylon to resist prints made with reactive dyes being distinguished by better fastness level, does not always produce satisfactory white resist effects when, for example, sulfite compounds as the resist agent and reactive dyes having esterified .beta.-hydroxyethylsulfonyl groups as the reactive radical are taken into consideration; colored effects having a bright hue are not even possible at all in various cases. It has now been found that, using sulfite compounds and reactive dyes of the vinylsulfonyl type, the above mentioned difficulties can be remedied when, instead of the ester derivatives of said dyestuffs, according to this invention such dyes which have been converted before they are applied into the free vinylsulfonyl form, are brought to interaction with the preprinted resist agent to become immediately and completely desactivated and thus resulting unobjectionable resist effects at the respective places of the textile material.

Process for producing white and colored resists on polyamide fiber

Vinylsulfonyl dyes, if padded from acidic liquors, produce on wool merely dyeings having a poor yield and only moderate fastness properties if the pad-beam method is used. It has been found according to the invention that padding from weakly alkaline liquor (pH 7-9) with sodium bicarbonate as fixing alkali and subsequent batching (6-24 hours) of the material produces good coloristic results especially on wools with a low-felting or non-felting finish.

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Kelkheim, Germany

Bernd Durl