EP0226982B1 - Process for dyeing wool - Google Patents

Abstract

1. A process for the level dyeing of wool or of the wool portion of fiber blends by the exhaust dyeing technique by applying an aqueous liquor of dyes which exhaust under strongly acidic conditions to the fiber material at a pH between 2 and 3 with heating, which comprises combining acid dyes which exhaust under strongly acidic conditions and reactive dyes with one another to form trichromatic recipes by replacing acid dyes of inadequate fastness by reactive dyes of the same or similar shade.

Description

The present invention relates to a process for the level dyeing of wool or the wool portion of fiber blends using the exhaust dyeing technique, in which aqueous liquors of dyes which are drawn under strongly acidic conditions are brought to action on the dye material with heating at pH values between 2 and 3.

The dyeing of wool from an aqueous medium with acid dyes at pH values from 2 to 3 is well known. This pH value is usually generated by adding strong acids to the dyebath, e.g. of sulfuric acid or formic acid. The dyes used in practice generally give a fastness level on the dyed textile material, which is sufficient for woolen piece goods, but is not sufficient for sliver, yarn or flake. The leveling behavior of the dyes applied in this way, on the other hand, is good and normally presents no difficulties.

However, wool dyeings with the ranges of such acidic dyes in trichromatic dyeing, and especially in the red and blue range of the color spectrum, often have weaknesses in terms of the wet fastness properties that compel the dye to have more genuine components with the to avoid the desired shade, which in turn brings complications with regard to the dyeing.

Likewise, dyeing wool with reactive dyes is now familiar to the person skilled in the art. This class of dyes is dyed on wool taking a variety of precautions at pH values in the range of 5.5 to 6.5. The said restrictive measures, e.g. Maintaining temperature levels, dyeing processes with very long heating times of the liquor etc. primarily serve to achieve level dyeings, because this is usually the problem with dyeing wool with a reactive dyeing machine. This results in dyeings with a very high level of fastness under these weakly acidic conditions.

The drawing card S 8126 "° Remazolan dyes on wool" from Farbwerke Hoechst AG from 1963 describes the dyeing of woolen articles with reactive dyes of the vinylsulfone type even from strongly acidic liquors, but the dyeing process explained there has not yet developed removes the prejudice that level stains can only be obtained if extended heating times are observed. However, the fastness properties of such dyeings produced in a strongly acidic environment are somewhat lower than the standard according to the working technique mentioned above for weakly acidic pH values.

The object of the invention in question was therefore to develop a dyeing process for wool, which allows the dyer to obtain trichromatic dyeings while maintaining excellent levelness under strongly acidic conditions, but with an increased fastness level, and which enables the fastness weaknesses in switch off the range of strongly acidic acid dyes without having to change the dyeing process.

The object set out above is achieved according to the invention by combining strongly acidic acid dyes and reactive dyes with one another in trichromatic recipes, acid dyes which are insufficient in the fastness properties being replaced by reactive dyes having the same or a similar shade.

However, the principle underlying the novel dyeing process must have seemed completely absurd to the expert, because on the one hand he is familiar with the good leveling behavior of the strongly acidic acid dyes - which is why he likes to use them for piece goods of wool - but on the other hand he knows about the leveling difficulties when dyeing wool with reactive dyes.

According to the invention, however, it has now been found that reactive dyes - especially of the type of vinyl sulfone compounds - allow level dyeings on wool at pH values of 2 to 3, the known, otherwise high level of fastness of dyeings with reactive dyes suffering only insignificant losses here . This unpredictable knowledge led to the combination of dyes from the two different dye classes in trichromatic recipes in order to achieve better wet fastness properties of the intended wool dyeings on this basis, without having to accept the risk of an uneven product appearance.

Now in GB-A-960 269, which deals with the uniform dyeing of wool / acrylic fiber mixtures from an acidic medium with reactive dyes in the presence of cationic auxiliaries, is mentioned that in special cases the tone-on-tone dyeing of both Fiber types can be influenced favorably by the use of whale dyes, so that they meet the required light and wet fastness properties. Nowhere in the GB-PS is there any mention of the replacement of strongly acidic acid dyes by reactive dyes.

For dyeing wool fibers or the wool content of fiber mixtures according to the present process, the chemical dyes listed in the Color Index, 3rd edition 1971 and supplements 1975 under the name "CI Acid Dyes" are used as acid dyes, with the restriction that according to the invention only those representatives of this dye category are considered useful for whose application the dyeing method 3 listed under the heading "The Dyeing of Wool" in volume 1, page 1001 is recommended. This applies to those dyes that are dyed using sulfuric acid.

As reactive dyes for the implementation of the invention come the organic known in the Color Index, 3rd edition 1971 and additions 1975 under the generic term "CI Reactive Dyes" Dyes into consideration which are able to form a covalent bond with fibers containing OH groups and / or NH groups. These are primarily dyes which contain at least one group which is reactive with hydroxyl or amino groups in the fiber material with a polyamide structure, a precursor for this or a substituent which is reactive with the constituents of the fiber molecule mentioned.

Preferably, dyes of the vinyl sulfone type are used for the present process, with which the fiber reacts via an addition mechanism via the vinyl sulfone form of the dye. In addition to the vinylsulfone residue itself as the group reactive with the textile material of wool, such dyes as precursors of this characteristic group can have the β-sulfatoethysulfone group, the β-chloroethylsulfone group or the ß-dialkylamino-ethylsulfone group, which during the dyeing process with the intermediate formation of the vinylsulfone - Form react with the fiber.

The conversion products of such known sulfonyl reactive dyes with e.g. Methyl taurine in which the reactive group is temporarily masked.

Reactive dyes with other reactive systems can only be used for the new process after an extremely strict selection, because only individual dyes from such ranges can be dyed regardless of the strongly acidic application conditions on wool.

It is all the more surprising that dyes which, in addition to a reactive residue of the vinylsulfone type or a reactive group described above as a precursor thereof, additionally have one or more groups which react with the wool according to the substitution mechanism, e.g. a monochlorotriazinyl or monofluorotriazinyl group, on wool articles according to the process give dyeings with excellent levelness and very high fastness properties.

Particularly suitable as the basic body of the chromophoric system of these organic dyes with reactive groups are those from the series of the azo, anthraquinone and phthalocyanine compounds, the azo and phthalocyanine dyes being both metal-free and metal-containing.

Reactive dyes of the type defined above often have more than one sulfonic acid group (except in the reactive grouping of the dye) in the molecule, which can be distributed arbitrarily over the chromophore, but are preferably bound to its armature radicals.

On the basis of the new process, the dyer is thus given the opportunity to use his dye store even better by combining conventional acid dyes with reactive dyes, without being forced to abandon the dyeing process introduced so far due to the shortcomings in trichromatic behavior To suffer loss of authenticity.

Sulfuric acid is expediently used as the acid for adjusting the pH from 2 to 3 in the dyeing according to the invention. Amounts of 3 to 5% of 96% H ₂ S0 ₄ , based on the wool weight, are required for this.

The pull-out dyeing method according to the invention mainly comes to ordinary, i.e. wool that has not been pretreated with an anti-felt finish or fiber mixes constructed in this way. In general, it is used for dyeing piece goods, where the leveling of the dyeings is particularly important. However, the higher authenticity level of the dyeings that can be achieved also allows this dyeing technique to be used for a different presentation of the wool in special cases.

There are two options for implementing the new procedure:

In the first mode of operation, the pull-out liquor is prepared at 50 ° C with all ingredients, such as the two types of dye, auxiliary materials and also the required acid. After a lead time of approx. 10 minutes together with the dye, the bath is now heated to the dyeing temperature (95 ° to 110 ° C.) within 30 to 50 minutes and the goods are then dyed for 60 to 90 minutes under these temperature conditions. The resulting dye is then cooled by adding cold water to the dyeing tank, then rinsed clear and dried.

The aforementioned method has certain disadvantages compared to the following variant, so that the latter will generally be preferred. These disadvantages are primarily the longer dyeing time (2 to 2 1/2 hours). In addition, carbonized wool must be neutralized before the dyeing process, which in turn means more time and more chemicals.

In the second process variant, the dye bath is set at 50 ° C with both types of dyestuff and auxiliaries, but without the sulfuric acid required for dye fixation, and the liquor - as quickly as the machine allows it - drives to the dyeing temperature (95 ° to 110 ° C) and then metered in the acid of the liquor under fixing conditions for the dyes over a longer period (20 to 40 minutes) in linear or progressive amounts, the time of metering being included in the total dyeing time of 60 to 90 minutes. There are very wide limits to the type of metering, and the relevant measures can be carried out discontinuously in portions and also continuously in terms of quantity in accordance with a predetermined time schedule. The dyed goods are then cooled, rinsed and dried.

This second process variant results in a significant reduction in dyeing time (only 80 to 120 minutes in total). The authenticity level of the dyeings as well as their loss (levelness) are completely preserved. It should be particularly emphasized that for the dyeing treatment according to this variant too carbonized wool is suitable, which does not have to be subjected to prior neutralization, so that the total time saved in this special case is even greater.

The following examples are not intended to restrict the claimed method in any way, especially not with regard to the dye combinations used, but merely serve to illustrate the procedure according to the present invention. The percentages contained in these exemplary embodiments relate to the weight of the objects designated in this way and, in the case of wool, are calculated on the dry state of the color material. The reactive dyes mentioned are used in commercial form and quality.

Dyes, which are conversion products of sulfonyl reactive dyes with N-methyl taurine, are present in the structure represented by the respective formula after being dissolved correctly.

Example 1 (process variant 1)

• 0,17% des Farbstoffes Acid Yellow 17 mit der C.I.-Nr. 18965 (1),
• 0,4% eines durch Umwandlung aus dem entsprechenden Farbstoff vom Vinylsulfon-Typ mit N-Methyltaurin erhaltenen roten Reaktivfarbstoffes der Formel ll
  
• 0,3% eines durch Umwandlung aus dem entsprechenden Farbstoff vom Vinylsulfon-Typ mit N-Methyltaurin erhaltenen blauen Reaktivfarbstoffes der Formel lll
  
• 10% Glaubersalz,
• 0,5% eines Hilfsmittelgemisches aus dem Umsetzungsprodukt von 1 Mol Stearylamin mit 12 Mol Ethylenoxid, versetzt mit Triisobutyulphosphat als Entschäumer, und
• 4% Schwefelsäure (96%ig).

50 kg of a wool fabric that has not been pretreated with an anti-felt finish are dyed at a liquor ratio of 1:15 with an aqueous liquor which has been prepared by adding the following ingredients to water at 50 ° C.

• 0.17% of the dye Acid Yellow 17 with the CI no. 18965 (1),
• 0.4% of a red reactive dye of the formula II obtained by conversion from the corresponding dye of the vinylsulfone type with N-methyl taurine
  
• 0.3% of a blue reactive dye of the formula III obtained by conversion from the corresponding dye of the vinylsulfone type with N-methyl taurine
  
• 10% Glauber's salt,
• 0.5% of an auxiliary mixture from the reaction product of 1 mol of stearylamine with 12 mol of ethylene oxide, mixed with triisobutyulphosphate as a defoamer, and
• 4% sulfuric acid (96%).

After the usual advance of the liquor loaded with the dyed material of about 10 minutes, the bath temperature is now raised to 98 ° C. within 40 minutes and the goods are then dyed for 80 minutes under these temperature conditions. Then the colored wool is cooled by adding cold water to the bath and the latter is then rinsed clear with further water.

After drying you get a very level and real dyeing of the wool fabric in a sand tone.

Comparison 1

• 0,17% des Farbstoffes Acid Red 42 mit der C.I.Nr. 17070

und erhöht die Menge des Farbstoffes I auf 0,25%, so erhält man bei sonst gleicher Färbeweise eine im Farbton ähnliche, ebenfalls egale Färbung, die jedoch durch Ausbluten des roten Säurefarbstoffes, in den Naßechtheitseigenschaften (DIN 54013 und DIN 54020) um 1 bis 1 1/2 Echtheitsnoten schlechter ist als die erfindungsgemäße Färbung.If you replace the dye II (red reactive dye) in the above recipe

• 0.17% of the Acid Red 42 dye with the CINr. 17070

and increases the amount of dye I to 0.25%, so with otherwise identical dyeing, a similar, equally level dyeing is obtained, but this is due to bleeding out of the red acid dye in the wet fastness properties (DIN 54013 and DIN 54020) by 1 to 1 1/2 authenticity marks are worse than the coloring according to the invention.

Comparison 2

• 0,15% des Farbstoffes Acid Blue 40 mit der C.1.-Nr. 62125

und färbt sonst gleich in Weise wie dort beschrieben, dann erhält man eine egale, im Farbton ähnliche Färbung, die jedoch durch Ausbluten des blauen Säurefarbstoffes in den Naßechtheitseigenschaften (DIN 54013 und DIN 54020) um 1 bis 1 1/2 Noten schlechter ist als die erfindungsgemäße Färbung.In the above recipe, replace dye III (blue reactive dye)

• 0.15% of the Acid Blue 40 dye with the C.1.-Nr. 62125

and otherwise dyes in the same way as described there, you get a level, similar coloration, but due to the bleeding of the blue acid dye in the wet fastness properties (DIN 54013 and DIN 54020) 1 to 1 1/2 grades worse than that coloring according to the invention.

Example 2 (process variant 2)

• 0,2% des Farbstoffes Acid Yellow 17 mit der C.1.-Nr. 18965,
• 0,3% des Farbstoffes Reactive Orange 16 mit der C.1.-Nr. 17757,
• 0,2% des Farbstoffes Acid Blue 41 mit der C.L-Nr. 62130,
• 10% Glaubersalz, und
• 0,5% des Hilfsmittelgemisches gemäß Beispiel 1.

To dye 20 kg of a woolen fabric that had been carbonized beforehand but has not yet been neutralized, by drawing out at a liquor ratio of 1:20, an aqueous liquor of 50 ° C. is used with:

• 0.2% of the dye Acid Yellow 17 with the C.1.-Nr. 18965,
• 0.3% of the dye Reactive Orange 16 with the C.1.-Nr. 17757,
• 0.2% of the dye Acid Blue 41 with the CL no. 62130,
• 10% Glauber's salt, and
• 0.5% of the auxiliary mixture according to Example 1.

• 4% Schwefelsäure (96%ig),

mittels Wasser verdünnt, kontinuierlich sowie bei Einhaltung einer pro Zeiteinheit mengenmäßig 40%igen Progression während eines Zeitraumes von 30 Minuten zuzudosieren. Im Verlauf des Dosiervorganges und danach weitere 30 Minuten wird das Ausziehbad am Kochen gehalten. Danach kühlt man Flotte samt Ware ab, spült letztere mit Wasser und stellt die gefärbte Wolle wie üblich fertig.After placing the goods in this dyebath, the latter is now heated as quickly as possible - modern equipment allows a heating up time of 10 minutes - to boiling temperature and begins immediately after reaching the same liquor under fixation conditions using an ADC 100 metering device from ADCON AB , Boras / Sweden

• 4% sulfuric acid (96%),

diluted with water, metered in continuously and in compliance with a 40% progression per unit of time over a period of 30 minutes. In the course of the dosing process and then for a further 30 minutes, the pull-out bath is kept boiling. Then you cool the liquor and the goods, rinse the latter with water and finish the dyed wool as usual.

A very level sand dyeing of the wool with good fastness properties is obtained.

Example 3

• Dazu werden in einem wäßrigen Bad von 50°C
• 1 % des Farbstoffes Acid Brown 248 mit der C.1.-Nr. 10402,
• 1 % des Reaktivfarbstoffes der Formel
  
• 0,8% des Farbstoffes Acid Blue 41 mit der C.l.-Nr. 62130,
• 10% Glaubersalz, und
• 0,5 des Hilfsmittelgemisches gemäß Beispiel 1

in Lösung gebracht. Man heizt dann diese Flotte zusammen mit der eingebrachten Ware im Verflauf von 10 Minuten auf 100°C auf und dosiert sofort nach Erreichen dieser Temperatur

• 5% Schwefelsäure (96%ig)

zu. Der Dosierungsvorgang wird hierbei manuell so vorgenommen, daß die Säure in 20 I kaltes Wasser eingegossen wird und vom Gesamtvolumen dieser verdünnten Säure alle 5 Minuten portionsweise lineare Mengen von jeweils 4 I (beim letzten Mal der gesamte Rest) dem Färbebad zugesetzt werden. Nach Beendigung des Säurezusatzes wird die Wolle noch 40 Minuten bi 100°C weitergefärbt, das Farbgut sodann abgekühlt, mit Wasser gespült und fertiggestellt.20 kg of a normal wool crepe fabric are to be dyed on the tree dyeing machine by pulling out at a liquor ratio of 1:10:

• This is done in an aqueous bath at 50 ° C
• 1% of the dye Acid Brown 248 with the C.1.-Nr. 10402,
• 1% of the reactive dye of the formula
  
• 0.8% of the dye Acid Blue 41 with the Cl no. 62130,
• 10% Glauber's salt, and
• 0.5 of the auxiliary mixture according to Example 1

brought into solution. This liquor is then heated together with the introduced goods in the course of 10 minutes to 100 ° C. and metered in immediately after this temperature has been reached

• 5% sulfuric acid (96%)

to. The metering process is carried out manually in such a way that the acid is poured into 20 l of cold water and linear amounts of 4 l each (in the last time the rest) of the total volume of this dilute acid are added to the dyebath every 5 minutes. After the acid addition has ended, the wool is further dyed at 100 ° C. for 40 minutes, the dyed material is then cooled, rinsed with water and finished.

You get a level, real brown color.

Claims (6)

1. A process for the level dyeing of wool or of the wool portion of fiber blends by the exhaust dyeing technique by applying an aqueous liquor of dyes which exhaust under strongly acidic conditions to the fiber material at a pH between 2 and 3 with heating, which comprises combining acid dyes which exhaust under strongly acidic conditions and reactive dyes with one another to form trichromatic recipes by replacing acid dyes of inadequate fastness by reactive dyes of the same or similar shade.

2. The process as claimed in claim 1, wherein the wool is dyed using dye combinations with reactive dyes which contain in their molecule at least one grouping which, under fixing conditions, reacts with the fiber via the vinylsulfonyl form by nucleophilic addition.

3. The process as claimed in claim 1 and 2, wherein the wool is dyed using dye combinations with reactive dyes which, in addition to a reactive group of the vinylsulfonyl type, have at least one monochlorotriazinyl or monofluorotriazinyl group.

4. The process as claimed in one or more of claims 1 to 3, wherein the exhaust liquor which contains such dye combinations and possibly all the other ingredients, but no acid or acid-donating agent required for fixing the dyes, is heated up together with the material to be dyed to the dyeing temperature within the range from 95° to 110°C as rapidly as possible and in one step, then, on reaching said dyeing temperature and while maintaining appropriate isothermal conditions for dye fixation, the hot dyebath has added to it sulfuric acid in portions over a prolonged period, and the wool is dyed in the indicated strongly acid pH range.

5. The process as claimed in one or more of claims 1 to 4, wherein wool which has not been pretreated with an antifelting finish is dyed.

6. The process as claimed in claim 1 and claim 4, wherein carbonized wool which has not been subjected to prior neutralization is dyed.