Process and agent for the one-bath reoxidizing and soaping of dyeings with vat or sulfur vat dyes with hypochlorite-releasing compounds and anionic detergents
AssigneeHoechst Aktiengesellschaft
InventorHeinrich O. Bernhardt
Life of this patent
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Abstract
The alkaline reoxidation of vat and sulfur vat dyes by means of hydrogen peroxide is difficult to control and to keep constant. By using agents which split off hypochlorite in the heat, for example sodium N-chloro-p-toluenesulfonamide, at pH values above 8 it is possible according to the invention even to reoxidize reliably combinations of these dyes having different oxidation behaviors. At the same time it became possible to combine the necessary soaping process with reoxidation.
Claims13
In a process for reoxidizing dyeings with vat and/or sulfur dyes which have been applied beforehand in reduced form to a textile material which contains cellulose fibers and have been fixed thereon, from an alkaline medium, wherein the textile material which has been treated with the above dyes alone or in combination with one another is exposed - for the dye development - to the oxidizing action of an aqueous solution of an oxidizing agent or mixture thereof selected from an N-chlorinated aryl- or alkylaryl-sulfonamide and N-chlorinated isocyanuric acid, at pH values above 8 and at a temperature between 15.degree. C. and the boiling point of the liquor, the improvement which comprises effecting the first soaping process of the fixed dyeing at the same time as the oxidation in the same bath, said liquor containingg anionic surfactants in addition to the oxidizing agent or mixture, under the above temperature and pH conditions.
The oxidizing and aftersoaping agent as claimed in claim 11, wherein for oxidation the sodium salts of N-chloro-p-toluenesulfonmaide, N-chlorobenzenesulfonamide, 1-chlorosulfamoyl-3-carboxylbenzene or N-chloro-o-toluenesulfonamide or dichloroisocyanuric acid are provided individually or in mixture with one another.
A process for the one-bath reoxidizing and scaping of a previously applied dyeing which is in a reduced form of a vat and/or sulfur dye previously applied from an alkaline medium and fixed on a textile material containing cellulosic fibers, siad process comprising;
- in a bath containing a reoxidizing agent and a soaping medium, developing said reduced form by exposing said textile material, on which said dyeing is fixed, to the oxidizing action of an aqueous solution of a reoxidizing agent which splits off hypochlorite when heated above 15.degree. C. but below the boiling point of the bath at a pH value >8, and
- at the same time, in the same bath, effecting a soaping step with the aid of the soaping medium, which medium comprises an anionic, hypochlorite-resistant surfactant.
Dependencies are inferred from the claim text.