DE253155C - - Google Patents

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- M 253155 CLASS Sn. GROUP

HIRSCH POMERANZ in MÜLHAUSEN i.Els.

Patented in the German Empire on April 25, 1912.

The production of white and colored etchings on indigo dyeings can except by Use of. Oxidation etching, to which include the well-known chromate, chlorate, and nitrate etches that carry the dye through Destroy oxidation, also take place by means of reduction.

These so-called reduction etchings are based on adding the indigo dye to the fiber

ίο vat, d. H. to reduce and indigo white by subsequent treatment with dilute alkalis in which the indigo white is soluble, remove the leuco product formed from the fiber.

The etching of this type is primarily the hydrosulfite etch, which is durable Fprmaldehyde hydrosulfite (or sulfoxylate formaldehyde) is printed on the dyed fabric and then steamed. By the action of the hydrosulfite, the indigo turns to Indig white reduced and this when passing through a hot, weakly alkaline bath of detached from the fiber. An otherwise easy re-oxidation of the indigo white to the To prevent bluish dye even before its removal from the fiber, hydrosulfite compounds are used expediently those substances are added that convert the resulting indigenous white into an air-resistant compound, but the alkaline ones. Passage does not resist and is therefore removed from the same. Among other things, this purpose is fulfilled by a dimethylbenzylphenylammonium chloride sulfonic acid, while the dimethylbenzylphenylammonium chloride even in the presence of zinc white with the indigo white introduced a permanent yellow connection, which as colored dots on indigo Can be used.

This hydrosulfite etch is the only reduction etch that has been used in practice. Other reducing agents have also been tried or patented, such as * z. B. glucose and caustic soda; furthermore, the tin salt rates and the zinc dust rates have also been tested without arriving at any practical results. Either colored reduction products are produced, or the alkaline etches, such as glucose and alkali, or the alkaline tin oxide products do not produce a completely pure white, since the re-oxidation of the indigo white produced is difficult to avoid, especially in the presence of caustic alkali.

So it is the formaldehyde hydrosulfite the only reduction rates that have been used up to now delivers safe, satisfactory result; it also has the before the oxidation etching Advantage of not attacking the fiber, while in the case of the former, the weakening of the fiber occurs more or less reliably due to the formation of oxycellulose.

The subject of the present invention now forms a new process to indigo to be etched white and colored on the reduction path; not only is it cheaper than that up now common hydrosulfite process, but is also particularly suitable for Colored etching with indanthrene colors and other vat colors.

The new process consists of etching indigo blue using iron oxide hydrate and Caustic soda. ,

It is known that iron oxide hydrate reduces indigo blue in the presence of water or alkali to indigo white. The dyeing process by means of the so-called Vitriol cup. If you print a thickened iron oxide salt on fabric dyed with vat blue on. and if this happens through caustic soda, iron oxide hydrate is first deposited on the printed areas,

ίο which sticks to the fiber; Further This Oxydul now has a reducing effect on the indigo, reducing it to indigo white, that of the latige detached and thus from the fiber Will get removed.

A re-coloring of the etched areas by the indigo white dissolved in an alkaline bath does not take place; on the one hand because of the temperature and the concentration do not allow the bath to be stained; on the other hand, this also has an effect on the etched one Protecting places in place with iron oxide until the fabric has left the stripping bath.

After the etched dye is completely removed, the iron oxide will through Acid removed from the fiber. The caustic power of the iron oxide hydrate can be as in the formaldehyde hydrosulfite process, by adding aithraquinone in the presence Reinforce small amounts of tin oxide. An addition of zinc chloride to the iron oxide sulfide

"Solution favors the etching, since the zinc salt when treated with lye in the moment of

Etching zinc hydroxide supplies, at the same time, however, larger amounts of iron vitriol in the

To solve etching paint. ,

This salt is the most useful because of its cheapness and sufficient shelf life Iron oxide salt; but other salts can also be used for the etching process.

will.

The present process also allows colored etching with indanthrene and other vat dyes can be achieved if an indanthrene dye and the necessary amount of tin oxide compound are added to the etching color. the The dyes are then fixed in a known manner during the alkaline passage, and in this way it is possible to obtain both white and colored etchings without a Steaming is necessary. In this respect too

The new etching process is superior to the hydrosulfurization process and to the chromate or chromate process. Nitrate etching process accordingly.

Example i.
White etchings on vat blue.

The fabric dyed with indigo is printed with the following etching, depending on the depth of the color: 150 to 100 g British gum, 420 to . ^. 180 g water, 150 to 200 g zinc chloride solution 55 ° Be. are boiled and dissolved in it 250 to 400 g of iron vitriol; then, after cooling, 20 to 40 g tin salt and 40 to 80 g anthraquinone paste 30 percent are added. ·.

After printing, the fabric is dried in a 70 to 80 ° C sodium hydroxide bath at 15 to 20 ° Be. pulled through for ¹ Z ₂ to ι minute; Then a second hot, weakly alkaline bath or soap bath is given for complete purification, rinsed in cold water and acidified from 40 to 50 g of sulfuric acid per liter in an approximately 50 ° warm sulfuric acid bath.

Example 2.
Light blue etchings on an indigo background.

Discharge ink. On the one hand, boil 150 g British gum with 360 g water and add to it 200 to 250 g iron vitriol. To better dissolve the salt, the color can be used if necessary another 50 g of aluminum chloride 22 ° Be. 40 g tin oxide paste 50 percent are added. On the other hand, 100 g of indanthrene blue RS (B.A. S.F.) i. T. with 30 g British gum and 50 g of water thickened.

The first batch is added in portions to the second with stirring. the further treatment of the printed material is carried out as in example 1.

Claims (1)

Patent claim: Process for the etching of vat blue dyed substance by reduction, characterized in that the fabric printed with iron oxide salts by a hot alkaline bath is drawn through, in which the reduction is carried out at the same time of the dye and its detachment from the fiber takes place.