DE570556C - Process for the production of black colorations on the vegetable fiber by means of Kuepen dyes - Google Patents

Description

Process for the production of black colorations on the vegetable Fiber by means of vat dyes It has been found that valuable black dyeings can be obtained on vegetable fibers, such as cotton, viscose rayon, etc., using vat dyes can be obtained if mixtures of dibenzanthrone and the nitration products are used for dyeing of the dibenzanthrone used. The black colorations obtained have practically good chlorine fastness, which was all the less foreseeable than those with the aforementioned Nitration products available on cotton when exposed to green from chlorine, as is well known, show a blatant turn to black. If you use namely when setting directly black-coloring mixtures in addition to the nitration products of dibenzanthrone as a violet dye z. B. dichloroisodibenzanthrone, so show When chlorinated, these mixtures show such a noticeable change to dark blue that they are practically unusable.

The mixtures mentioned can be prepared in such a way that one dibenzanthrone with its nitration products obtainable by the process of patent specification 185222 mixes, or because: ß one treats dibenzanthrone with nitrating agents so that only partial nitration occurs. By changes in the ratio of the components or the concentration of the nitric acid used in the nitration or des Solvent or suspending agent in which the partial nitration of dibenzanthrone is carried out, you can get more or less reddish bluish black or more greenish black Achieve nuances.

Those are particularly valuable in terms of shade and chlorine fastness Products that contain between about 55 to 90 parts of pure dibenzanthrone to 45 to 10 parts contain nitrated dibenzanthrone. If necessary, small amounts can also be more suitable Setting dyes are added.

If impure dyes are used, the ratio may shift considerably; z. For example, 10 parts of inverted dibenzanthrone with 40 parts of crude dibenzanthrone nitrated in dilute sulfuric acid give a product which immediately gives valuable black colorations. Example i 87 parts of pure dibenzanthrone, obtainable e.g. B. by umküpen the crude dye obtained in the potash melting of benzanthrone, filtering the vat and blowing out the hydro-compound or by fusing benzanthrone with potash in aniline suspension according to patent 290 079, 13 parts of the nitration product of dibenzanthrone, which is commercially available under the name Anthragrün B, are added mixed. About 7 percent dyeing of the product on cotton is a reddish blue-black with excellent chlorine fastness. If 67 parts of pure dibenzanthrone and 33 parts of the cited nitration product of dibenzanthrone are mixed in place of the quantitative ratio given above, a less reddish-tinged black is obtained which is likewise good in fastness to chlorine.

If the raw dibenzanthrone is used instead of the pure dibenzanthrone, then it must be used you naturally use a correspondingly larger amount to achieve the same shade.

Example .2 100 parts of pure dibenzanthrone are suspended in 600 parts of nitrobenzene. Then, at 30 %, parts of a nitric acid of 82 percent are added. The reaction mixture is kept at 65 ' for 2 hours and distilled, for. B. the nitrobenzene with steam. The remaining dye gives black shades of good chlorine fastness in 6 percent dyeing on cotton.

The filtration can also be carried out in other solvents or diluents, z. B. 96 percent or 8 percent sulfuric acid.

Claims (1)

PATENT CLAIM: Process for the production of black colorations the vegetable fiber by means of vat dyes, characterized in that one for coloring, mixtures of dibenzanthrone and the nitration products of dibenzanthrone used.