DE2511535C2 - PROCESS FOR CONTINUOUS FIXING OF HYDRO-SOLUBLE SULFUR DYES ON CELLULOSE FIBERS - Google Patents

Description

Na ₂ S,
corresponds to where χ is a number from 2 to 5.

Water-soluble sulfur dyes (C. L: Solubilized Sulfur Dyes) have been known for a long time and are in the Practice very well established for dyeing cellulose fibers

In the production of these dyes one starts from the water-insoluble sulfur dyes (C1: Sulphur Dyes), which are converted into their water-soluble leuco form (-SH) with reducing agents (hydrogen donors) transformed and then with sulphites to derivatives of thiosulphuric acid

FS-SO ₃ Na

60

implemented. These so-called Buntesalz dyes are essentially free of reducing agents, soluble in water, not spontaneously reoxidizable with atmospheric oxygen and therefore stable in aqueous solution.

In this form, they show no affinity for cellulose fibers, and the practically neutral liquors result in no swelling on cellulose fibers, which has advantages with regard to the equality of ends in pad dyeings and the coloration result.

If this colored salt form (on the fiber or in the Rotte) exposed to the action of reducing agents (preferably Alkalisufklen), so in the alkaline Medium restored the above-mentioned leuco form. This SH form has an affinity for cellulose fiber. The final and complete fixation takes place after a steaming process by reoxidation (mostly in acidic medium), in which the original disulfide form (- S - S -) is re-formed.

For continuous dyeing of cellulose material A number of processes are known with water-soluble sulfur dyes:

Single-bath pad steam process

The dissolved dye is padded with the reducing agents (alkali metal sulfides such as sodium hydrogen sulfide and sodium carbonate) cold to the tissue and without intermediate drying immediately for about 40 seconds at 110 ⁰ C in a steamer with air-free saturated steam damped The (mostly acidic) oxidation and the usual rinsing and Washing operations are carried out on a wide washing machine. Since the dye and reducing agent have already reacted with each other and the sulfhydryl form of the dye has an affinity for the fiber, in some cases it is necessary to dilute the batch (first chassis filling) by about 20% and use a chassis to achieve colorations with the same ends to block the smallest possible volume.

Two-bath pad steam process

The hot solution of the dye is padded onto the fabric without a reducing agent and this in the hot flue is dried. The textile material is then placed on the chemical pad with the solution padded with the alkaline reducing agent, steamed immediately and treated further as with the one-bath process

A weakening of the approach is not necessary However, the reducing agent solution occasionally receives an addition to the dye liquor when it is first used. to prevent any detachment in the chassis of the chemical pad. One achieves With this method, the ends are identical and colored through.

In both cases, a steaming process is required for fixation. Although the two-bath process has advantages offers compared to the single bath process, especially with regard to the product image, this is because of its simpler way of working preferred.

Block thermosetting process

In this method, the dye is padded as an aqueous solution in the presence of urea and a specific Fixierhilfsmittels to the fabric at about 3O ⁰ C, dried at 100 to 102 ° C and finally thenmofixiert 60 seconds at about 160 ⁰ C with dry heat. The post-treatment is carried out in the broad state by rinsing, reoxidation is not necessary.

The advantage of this process is that the fabric looks good even with uneven woven fabrics. It However, only medium depths of color can be achieved with this, the coloring of regenerated celluloses is not possible recommended, the dyeing process can be combined with a finishing process. Instead of

A thermal treatment occurs here during the steaming process with dry heat.

The invention relates to an economical continuous process for dyeing cellulosic fibers in sheet form with water-soluble Schwefelfarbstof- s fen, wherein the good absorbent textile material is first warm on a padder with a relatively low wet pick-up with a 40 to 50 ⁰ C aqueous solution is padded, the contains one or more water-soluble sulfur dyes (Solubilized Sulfur ι ο Dyes) and 20 to 30% by weight of the amount of sodium sulphide empirically determined as sulphide requirement for a complete reduction of the dye in question (in the SH form) without intermediate drying on a Chemikaüenioulard with significantly higher flotia uptake with a hot (preferably near the boiling point) aqueous solution pods the further 30 to 20% by weight of the amount of sodium sulphide measured as the specific sulphide requirement (see above) amount applied in both padding processes Sodium sulphide does not need to exceed a value of 50% by weight of the known sulphide requirement. This second liquor also contains an addition of sodium polysulphide as an aqueous solution. To convert the dyes applied to the fiber into their water-insoluble Dtsulfidform, instead of a steaming operation, the textile web is ventilated for at least 10 seconds, preferably 30 to 40 seconds (corresponding to about 15 m), expediently at room temperature, and the goods are then passed through the wide washing machine with rinsing and oxidation process, as is customary for pad dyeing with sulfur dyes

In the context of the process according to the invention, the sodium polysulfide used is compounds of the formula

Na ₂ S,

into consideration, wherein χ is a number from 2 to 5. It is the second padding liquor in amounts corresponding to 8 to 10% of the weight of the goods, expediently in the form of a aqueous, 15% solution added

As an additive to the chemical liquor, the sodium polysulphide has the purpose of spontaneous oxidation of the To prevent the sulfhydryl form of the dye during the passage of air through the oxygen in the air and thereby allow complete diffusion into the fiber and fixation of the dye.

However, the sodium polysulphide acts as a redox buffer, of the _so highly negative redox potential (low rH-value) of the sulfur atrium by its own positive potential something printed result, the Spontanoxydation of the leuco dye is reacted with oxygen on the duration of the air passage prevents The redox capacitance with respect to the dye is increased rt.

This effect of the sodium polysulfide in this Direction is new and surprising.

Compared to the conventional staining methods of the state of the art, the process offers the following &, Advantages:

Simplified way of working.
Time and energy savings by eliminating intermediate drying and the steaming or dry heat setting process. 6s

Very good dye penetration and levelness, smooth appearance, even deep dyeings with full Dye yield possible.

Lower amounts of reducing agent (50% of the prescribed amounts), this also reduces wastewater pollution
A sufficient difference in the liquor uptake on the two padding pads, the dye padding and the chemical padding, is a necessary prerequisite for this process. The liquor absorption ties chemical foulards must always be higher than that of the dye foulards.

In the amount of the liquor that the goods after the first pad can still be added to the second pad, it must be for the padded Dye necessary residual amount of chemicals can be accommodated.

But since the solubility (at room temperature) of the mainly used sulfides, sodium hydrogen sulfide and sodium sulfide crystal is very good, even with small differences in the uptake of the liquor Fixations are carried out by the method according to the invention.

The liquor recordings are not only from the adjustable pressure of the padder rollers, but also depends on the quality of the goods and must therefore be determined as precisely as possible on a case-by-case basis.

The chemical concentration is calculated according to the following general scheme:

It means:

A = amount of dye in% of the weight of the goods,
B - liquor pick-up on the dye padder in%

the weight of the goods
C = liquor pick-up on the chemical pad in% of the weight of the goods

F = ratio sulphide / dye (specific sulphide requirement, equivalence factor. Compared to the information in the information documents on the specific sulphide requirement of the individual dyes, this factor is reduced by half for this process).

We are looking for:
χ = batch concentration of the dye in g / l

1000/1

B / l,

y = batch concentration of the sulfide in g / l or cmVl
1000 A-F

y =

g / l or cnrVl

and when using sodium hydrogen sulfide (solution, commercially available)
ζ = batch concentration soda lime. in g / l

but at least 4 g / l soda lime.

The sulphide requirement expresses how many parts (with a safety excess) sodium sulphide per part of the water-soluble sulfur dye are required to convert this specific dye into by reduction transfer its fiber-affine SH form. These are experimentally determined values that higher than a theoretical equivalent.

Such guide values (factors) for water-soluble sulfur dyes of the thiosulfonic acid type

(FS-SO ₃ H)

are generally used in practice and are listed in the literature

As an example of such figures in the case of commercially available water-soluble sulfur dyes is on the sample card C 669a »Hydrosol and Hydrosol light dyes on pieces of cotton as well Cotton and viscose filament yarn «from Cassella Farbwerke Mainkur AG, Frankfurt (Main) -Fechenheim referenced, the following compilation in extracts is taken from:

Specific sulphide requirement: Na ₂ S or NaHS, depending on the respective dye

χ parts dye - factor F = y parts sulfide
Table: »Sulphide requirement«

C. 1. No. Solubilized Sulfur Factor F 53121 Yellow 2 1 53066 Brown 21 2 53056 Brown 10 1.5 53326 Brown 60 13th 53328 Brown 51 2 53001 Brown 1 1 53286 Brown 16 1 53321 Brown 52 1 53271 Brown 15 1.5 53724 Brown 12 03 53723 Red 6 1 5344 t Blue 7 1.5 53471 Blue 10 0.75 53481 Blue 2 0.75 53481 Green 2 0.75 53573 Green 3 03 53006 Green 9 2 53186 Black I 2 - Green 19 1 _ Red 11 2 _ Blue 11 1

Attention is drawn to the corresponding tables from other dye manufacturers.

example

Em cotton body is ^{padded at 40 0} C, a liquor pick-up of 60% (of the fabric weight) and a fabric speed of 30 m per minute on a padder with an aqueous liquor which contains per liter:

65 g / l Solubilized Sulfur Green 9, C I. Nr. 53006,
15 g / l Solubilized Sulfur Brown 16,

CL No. 53286,
13 g / l Solubilized Sulfur Brown 51,

C 1st no. 53328,
3 g / l of an anionic wetting agent based on

Alkanesulfonate and
25 g / l sulfur sodium conc. (corresponds to 30% of the

Total Na ₂ S requirement).

The textile material is then dried without intermediate drying on the chemical foulard with a liquor pick-up of 80% (of the weight of the goods) and at 95 ° C the aqueous chemical fleet, which contains per liter:

90 g / l sulfur sodium conc. (corresponds to 20% of the

Na ₂ S requirement) and
40 g / l of a 15% strength aqueous solution of a

Sodium polysulfide with average Sulfur content of 2 to 5 atoms each

Molecule.

The first chassis filling of the chemical padding contains an addition of 50 cm ³ / l of the above-mentioned dyestuff padding liquor.

The goods treated in this way then passed an air passage of 15 m (corresponds to 20 to 40 seconds) which does not spontaneously oxidize the leuco compounds, and is then put on the washing machine in the same usual way as sulfur coloring by rinsing, oxidizing and rinsing further and post-treated.

You get a level and very well colored product in a full olive shade, the depth of which is the corresponds to the amount of dye used, i.e. it the dyes used are completely fixed.

Claims (3)

Patent claims: 1. A process for the continuous dyeing of cellulose fibers in web form with water-soluble sulfur dyes by a padding process without subsequent steaming for dye fixation, characterized in that the textile material is first used on a padder at a relatively low liquor pick-up and a temperature of 40 to 50 ^° C an aqueous solution that contains one or more water-soluble sulfur dyes (Solubilized Sulfur Dyes) as well as 20 to 30 wt treated goods then without intermediate drying on a chemical padding with a significantly higher liquor pick-up with a hot aqueous liquor padding the further 30 to 20% by weight of the amount of sodium sulfide measured as the specific sulfide requirement (see above), although the amount of sodium sulfide applied in both padding processes a A value of together 50% by weight of the known sulfide requirement does not need to be exceeded and an aqueous sodium polysulfide solution has been added, the textile web is subjected to an air flow of at least 10 seconds and finally - as is usual for block dyeings with sulfur dyeings - dyeing by rinsing, oxidizing and completing another rinse on the wide washer to form the water-insoluble disulfide form of the dyes on the fiber 2. The method according to claim 1, characterized in that the second padding liquor is 8 to 10% of the weight of an aqueous, approximately 15% strength solution of sodium polysulfide is added 3. The method according to claims 1 and 2, characterized in that the sodium polysulfide of formula