DE4306589A1 - Process for dyeing synthetic fibres and fibres dyed by the process - Google Patents

Abstract

The invention relates to a process for dyeing synthetic fibres, especially polyacrylonitrile fibres in a blend with wool fibres, using customary dyes and dyeing assistants in the dyeing liquor. The process is characterised by the use, as a boiling deterioration inhibitor, of a chlorate salt which is soluble in the dyeing liquor and acceptable from a waste water treatment technology and dyeing technology point of view.

Description

The invention relates to the dyeing of synthetic fibers and ins especially the dyeing of acrylic fibers mixed with wool fibers.

When dyeing fibers or fiber mixtures, be it in the form of Threads or as already woven or knitted fabrics dyes are often used in the dyeing process before Destruction must be protected. Such destruction will also known as overcooking. For this purpose, serve as ver anti-boil designated coloring aid, it are mildly oxidizing substances that are reducing capable of oxidizing active substances in the dyeing liquor. For example, without the addition of overcooking inhibitors with acrylic dyes often a reductive destruction Reduction of the color depth and the color tone on the goods. Such destruction causing agents in staining brisk or in the substrate to be colored z. B. be:

• - Humic acids used in the preparation of the dye liquor Water;
• - Use heavy metal ions in the dye liquor detergent or in the dye liquor deten fabrics;
• - reducing functional groups in the coloring substrate, e.g. B. the SH groups in the wool.

So far, either chrome (VI) salts or aromatic nitro compounds used, for. B. the Boil-off inhibitor with the product name Lyoprint RG®. However, the use of these known compounds is  problematic in terms of wastewater since chromium (VI) salts are extremely high are toxic and the use of aromatic nitrover bonds appear ecologically questionable.

The object of the present invention is therefore an improved one Dyeing process using anti-scaling agents, which only have a medium oxidation potential to color substrate and Dyes not attack, which have the exclusion of Heavy metals, especially chromium (VI) salts, allow which the so-called AOX value of the waste water, d. H. the value of adsorbable organic halogen compounds in waste water, not significantly increase and if possible during the dyeing process largely too ecologically and wastewater-friendly Connections are cleared down.

The method according to the invention serves to achieve this object of the aforementioned type, which is characterized by that one dissolves in the dyeing liquor as a preventive agent sewage technology and dyeing technology acceptable Chlorate salt used.

This is one of the chlorate salts that is acceptable from a wastewater point of view Chlorate to understand that none harmful to wastewater Introduces heavy metals into the dyeing liquor. Under dyeing acceptable chlorate salt is understood to mean a chlorate salt which does not introduce any cations into the dyeing liquor that precedes the dyeing adversely affect gear.

As cations of the chlorate salts soluble in the dye liquor are therefore advantageously common alkali or Alkaline earth ions selected, for cost reasons Alkali chlorates, especially sodium chlorate, are preferred is.

An advantage of using chlorate salts is that  their effect as a boil-off prevention with increasing temp rature increased.

Another advantage of using chlorate salts is theirs Handling with reasonable security effort.

Surprisingly, it was also found that the one set of soluble sodium chlorate in the dye liquor no Er increase in the AOX value, but on the contrary the AOX Value in some cases even compared to without chlorate addition or other additives carried out dyeing operations was set. It was also surprising that chlorate, which as strong oxidizing agent is considered in the dye liquor does not cause oxidative destruction of the dyes, but that their coloring power and the color depth and hue of the colored ten goods is retained. It is believed that the chlorate its oxidative and thus protective we in the dyeing liquor kung unfolded only when the temperature rises, so that this oxidative effect does not destroy the dyes leads.

The chlorate present in the dye liquor is pre-dyed gang, probably through different transition stages, to im Wastewater harmless at the concentrations present Degraded sodium chloride.

It is believed that the protective effect of chlorate in Dyeing goods containing wool fibers, d. H. Threads or Textiles, is based on the fact that the HS and -S-S groups of the in the amino acids cysteine, methionine and Lanthionine, with the -S-S groups participating in the dyeing process are broken down wisely to amino acids containing SH groups, is based on the fact that these HS groups are oxidized so that they no longer have a reducing effect and oppose them dyes used, especially cationic acrylic paints fabrics, behave indifferently.  

In experiments, fibers were made from a mixture of 40% wool and 60% polyacrylonitrile with the color 1613 wine red (internal Color code) dyed in the usual way, 5.4 kg of fibers in 40 l dyeing liquor, consisting of 2% acetic acid, 0.2% astrazon yellow GLE 200%, 1.325% Maxilon red GRL 150% and astrazon blue BRL 200% with an addition of 0.1% sodium chlorate, based on Goods weight, were dyed at 102 ° C for 30 min. The aftertreatment with acetic acid and ammonia was carried out in well-known way.

The AOX value of the used dye liquor was 4.9 mg / l. There was no sodium chlorate in the used dye liquor can be demonstrated in the analysis with KJ / starch.

When repeating the same dyeing process, but without addition of sodium chlorate, on the other hand, had an AOX value of 6.5 mg / l.

With the addition of sodium chlorate to the dyeing liquor Coloring process carried out were the color depth and hue of the dyed goods much better than in the dyeing process without the addition of sodium chlorate.

Claims (4)

1. A process for dyeing synthetic fibers, in particular polyacrylonitrile fibers in a mixture with wool fibers, using a set of customary dyes and dyeing aids in the dyeing liquor, characterized in that a chlorate salt which is soluble in the dyeing liquor and which is acceptable in terms of wastewater treatment and dyeing technology is used. 2. The method according to claim 1, characterized in that one used as chlorate sodium chlorate. 3. The method according to claim 1 or 2, characterized in that the chlorate salt in a concentration of 0.01 to 1 wt .-% chlorate ions, based on the weight of the goods coloring fibers. 4. Dyed plastic fibers, especially mixtures of Polyacrylonitrile fibers with wool fibers, or hereby provided substances, characterized in that under Ver application of a soluble, wastewater technology and dyeing nisch acceptable chlorate salt dyed in the dye liquor have been.