EP0226198B1 - Process for isothermic quick-dyeing of wool - Google Patents

Abstract

The dyeing of wool with reactive dyes in a strongly acid medium (containing sulfuric acid) requires no longer acceptable, long heating-up times (50-60 minutes) in order to obtain level dyeings. It has now been found, according to the invention, that by rapidly heating up the dyebath which contains the dyes of the vinylsulfonyl type and also all the ingredients, except the acid, to the dyeing temperature together with the material to be dyed and then metering in the sulfuric acid under isothermal conditions at the dyeing temperature it is possible to obtain very level and very fast dyeings in a significantly shorter overall dyeing time. Carbonized wool can be dyed without prior neutralization.

Description

The present invention relates to a process for the level dyeing of wool or the wool portion of fiber mixtures according to the pull-out dyeing technique in a strongly acidic medium with aqueous liquors of reactive dyes which have at least one group in their molecule which, under fixing conditions with the fiber via the vinyl sulfone form nucleophilic addition occurs in reaction.

The dyeing of wool with reactive dyes is well known in practice. As a rule, the textile material is treated with aqueous solutions of these dyes at temperatures of 98 ° C. to 106 ° C. and, depending on the desired depth of color, at precisely staggered pH values between 4.5 and 6.5 in order to achieve level and true dyeings .

In addition, in the sample card S 8126 " ^O Remazolan dyes on wool" from Farbwerke Hoechst AG a process is described according to which reactive dyes of the vinylsulfone type in the form of the β-sulfatoethylsulfone derivatives are extracted from strongly acidic liquors at pH values of 2 to 3 (adjusted with sulfuric acid) on wool items. This procedure is characterized by a very slow heating of the dyebath from the initial temperature of 50 ° C to the actual dyeing temperature of 98 ° to 100 ° C and a subsequent long dyeing time of 60 to 90 minutes at the dyeing temperature. In total, pure dyeing times of 2 to 2 1/2 hours are expected for the implementation of this dyeing technique. Here one started from the idea that level dyeings can only be obtained if extended heating times are taken into account.

The fastness properties of such reactive dyeings on wool which can be achieved by the conventional method in a strongly acidic environment are comparable to those produced with weakly acid-absorbing wool dyes and are absolutely acceptable and customary for normal wool articles. Disruptive to this known dyeing process for wool, however, are the long dyeing times required for this and the sometimes not sufficient levelness of the dyeings with the reactive dyes.

All of the above-mentioned dyeing methods according to the prior art have the prerequisite that reactive dye and acid (fixing aid) are present from the start side by side in the pull-out bath that has already been filled with the woolen dye, the actual fixing process occurring under the interaction between the reactive dye and the wool fiber is controlled solely by increasing the liquor temperature.

The object of the invention in question was therefore to develop a rapid dyeing process for wool with reactive dyes by the exhaust method, which, in addition to good levelness of the dyeings, has sufficient fastness properties thereof with a significant reduction in the total treatment time for the dye material compared to the working methods of the same type previously introduced for dyeing leaves.

The object set out above is achieved according to the invention in that the reactive dyes of the vinylsulfone type and, if appropriate, all other ingredients, but no pull-out liquor containing the acid or acid-releasing agent required for fixing the dyes together with the dyestuff as quickly as possible and all at once Dyeing temperature in the range of 95 ° to 110 ° C heated that after reaching the same while maintaining appropriate isothermal conditions for dye fixation, the heated dye bath then sulfuric acid - distributed over a longer period of time - is added and the wool at pH values between 2 and 3 colors.

"As soon as possible" in connection with the characteristic of this invention means according to the performance of the dyeing machines used. Modern machines allow heating times between 10 and 15 minutes. "In one go" is intended to express that the actual dyeing operation takes place without passing through graduated temperature conditions during the fixing process of the dyes. "Isothermal conditions" is understood to mean that the temperature of the liquor and the goods is kept constant during the treatment step of adding the acid and the subsequent dyeing time.

The metering of the acid over a longer period of time to the dye liquor based on fixing conditions for the dye can be carried out quantitatively both linearly and progressively, but the time at which the bath temperature is kept constant in the course of the acid inflow is included in the total dyeing time and consequently, the latter is not extended in accordance with the procedure. The pure dosing time can be from 10 to 45 minutes, which advantageously shortens the total dyeing time (including dosing time) to a maximum of 70 minutes.

With a linear dosage of the acidic fixative, the same amount of acid is introduced into the dye bath per unit of time. This can be done by introducing the sulfuric acid, usually diluted with water, either discontinuously in the same portions and at the same time intervals, or by continuously flowing it in the same amount per unit of time.

A progressive dosing of the acidic fixative brings an increasing amount of acid into the dye bath per unit of time as the dosing time progresses, which can also be done manually. Heuer dosing devices do this type of dosing automatically, so that then only the desired slope of the progression according to a predetermined mathematical function, e.g. B. linear. exponentially or in the manner of a parabolic function that needs to be set.

The amount of sulfuric acid to be introduced - like the dyeing time - depends on the desired depth of dyeing. If you charge 96% sulfuric acid, 3 to 5% of the wool weight is required. However, the concentrated acid in the claimed process is expediently diluted with water. On the one hand, this reduces the dangers of handling the acid, on the other hand allows a staggered, more even dosage.

The dyeing method according to the present invention mainly comes down to ordinary, i.e. H. wool that has not been pretreated with an anti-felt finish or fiber mixes constructed in this way. In this context, wool is understood to mean that in any processing state, that is to say as a flake, sliver, yarn, piece goods or also in the form of finished parts. It should be particularly emphasized that carbonized wool is also suitable for the dyeing treatment according to the invention, which need not be neutralized before dyeing. With all other dyeing processes for wool, this is a prerequisite for level dyeing failure. This time can also be saved in the new method, so that the total time saved is even greater.

Even felt-free or low-felt finished wool can be dyed no matter by the dyeing technique according to this invention, but in general the achievable wet fastness properties are not sufficient for this article, so that the claimed process will only arouse interest in exceptional cases.

For dyeing wool fibers or the wool content of fiber mixtures according to the present method, the organic dyes known from this generic term of the vinyl sulfone type are considered as reactive dyes, with which the fiber reacts via an addition mechanism via the vinyl sulfone form of the dye. This class of dyes is referred to in the Color Index, 3rd edition 1971 and additions in 1975 as "C.I. Reactive Dyes" and comprises chemical compounds with dye character which are able to form a covalent bond with fibers containing OH groups and / or NH groups. In addition to the vinylsulfonyl radical itself, as the group which is reactive in such dyes with hydroxyl or amino groups in the fiber material with a polyamide structure, in this respect there are predominantly precursors of this characteristic grouping, in particular the β-sulfatoethylsulfone group, the β-chloroethylsulfone group or the Belong to β-dialkylamino-ethylsulfone group, which react with the fiber during the dyeing process with the intermediate formation of the vinylsulfone form.

The conversion products of such known sulfonyl reactive dyes with z. B. methyl taurine, in which the reactive group is temporarily present in masked form.

Surprisingly, however, dyes which, in addition to a reactive radical of the vinylsulfone type or a reactive grouping already described as a precursor thereof, additionally result in a grouping which reacts with the wool according to the substitution mechanism, for. B. a monochlorotriazinyl or monofluorotriazinyl group, very level dyeings with even better fastness properties.

Particularly suitable as the base of the chromophoric system of these organic dyes are those from the series of the azo, anthraquinone and phthalocyanine compounds, it being possible for the azo and phthalocyanine dyes to be 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 as desired over the chromophore, but are preferably bound to its aromatic radicals.

The process itself is basically carried out as follows, whereby the type of metering can be given a wide range of variation, as can already be seen from the metering times mentioned. In general, the acid is added diluted, which allows a better dosage gradation:

The aqueous dyebath is prepared with all the ingredients, such as dye, auxiliary agents and any chemicals, except for the acid required, and is driven together with the dyestuff, as quickly as the machine allows, to the dyeing temperature which is dependent on the fiber material. In the course of the heating-up phase, a time saving of 10 to 40 minutes is achieved compared to conventional working methods. Immediately after reaching this dyeing temperature, the metered addition of the required acid is started. It can be taken in portions according to a certain schedule, such as. B. in the following example 1, or continuously according to a predetermined mathematical function (linear or z. B. exponential or in the manner of a parabolic function) with a dosing device, for example according to the principle as it is in the European patent application EP-A2- 0 126 042 is explained. Devices of this type have been on the market recently.

The bath temperature is kept constant during the acid addition and for a certain time afterwards. After the intended dyeing time, the dyeing is completed as usual for wool.

As far as the dyeing result achieved according to the invention is concerned, it was surprising to the person skilled in the art that level dyeings with a high level of fastness can be obtained in a short time on wool under the strongly acidic dyeing conditions with reactive dyes, it had previously been assumed that with decreasing pH -Value the level of authenticity of wool dyeings with reactive dyes drops sharply. The good coloration of z. B. Felting is a special feature of the new process. Also to be emphasized are the excellent surface and fiber levelness of the dyeings.

The authenticity level of wool articles dyed according to the process, which is already at the level of real acid dyes after the dyeing process has been completed, can be further improved by ammonia aftertreatment of the dyeing at pH 8 to 8.5 and 80 ° C. for 10 minutes.

The following examples are not intended to restrict the claimed process in any way, especially not with regard to the reactive dyes 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 are in the case of wool to the dry state of the color material calculated. 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 in accordance with the regulations.

example

• 3 % des Reaktivfarbstoffes mit der Formel
  
• 1 % eines durch Umwandlung aus dem entsprechenden Farbstoff vom Vinylsulfon-Typ mit N-Methyltaurin erhaltenen Reaktivfarbstoffes der Formel
  
• 1,5 % eines Hilfsmittelgemisches aus dem Umsetzungsprodukt von 1 Mol Stearylamin mit 12 Mol Ethylenoxid, versetzt mit Triisobutylphosphat als Entschäumer, und
• 10 % Glaubersalz.

To dye 80 kg of a knitted wool fabric that has not been pretreated with an anti-felt finish using the pull-out technique at a liquor ratio of 1:10, an aqueous bath of 40 ° C. with the following ingredients is prepared in a dyeing machine:

• 3% of the reactive dye with the formula
  
• 1% of a reactive dye of the formula obtained by conversion from the corresponding dye of the vinyl sulfone type with N-methyl taurine
  
• 1.5% of an auxiliary mixture from the reaction product of 1 mol of stearylamine with 12 mol of ethylene oxide, mixed with triisobutyl phosphate as a defoamer, and
• 10% Glauber's salt.

• 4 % Schwefelsäure (96 %-ig),

was einem Flüssigkeitsvolumen von 3,2 I entspricht. Diese Dosierung soll nach gleichen Zeitabständen portionsweise, aber mengenmäßig progressiv vorgenommen werden. Dazu verdünnt man die Säure durch Eingießen in kaltes Wasser auf ein Volumen von 15 l und setzt von dieser Lösung nach jeweils 7 Minuten die folgenden Mengen im Einklang mit der unten angegebenen Staffelung zu:

The wheel loaded with the colored material is now brought into circulation and heated to the dyeing temperature of 100 ° C. within 10 minutes. Immediately after reaching this temperature, the total addition is started.

• 4% sulfuric acid (96%),

which corresponds to a liquid volume of 3.2 I. This dosing should be carried out in portions, but progressively, in equal quantities. To this end, the acid is diluted to a volume of 15 l by pouring it into cold water and the following amounts of this solution are added after 7 minutes in accordance with the staggering given below:

During this measure, the temperature of the bath is kept constant at 100 ° C. The acid introduced has therefore been preheated to about the dyeing temperature.

After the addition of acid, which has led to a pH of the bath of 2.3, has ended, the goods are further dyed for a further 30 minutes at the same temperature. Then the extracted liquor, including the dyed wool, is cooled, the latter rinsed with water and finished as usual.

A brilliant red dyeing of the knitted fabric with good general fastness properties is obtained. Contrary to expectations, the levelness of the coloring is very good, the coloring is excellent.

Example 2

• Dazu wird das Farbgut in eine wäßrige Flotte von 40° C eingebracht, die als Bestandteile
• 3 % des Farbstoffes Reactive Blue 19 mit der C.I. Nr. 61200,
• 1 % des Reaktivfarbstoffes der Formel
  
• 1,5 % des Hilfsmittelgemisches gemäß Beispiel 1, und
• 10 % Glaubersalz

enthält, worauf man dieses Färbebad in Zirkulation versetzt und es innerhalb von 10 Minuten auf die Färbetemperatur von 100°C erhitzt. Dann werden der unter Fixierbedingungen befindlichen Flotte über ein Dosiergerät vom Typ ADC 100 der Firma ADCON AB, Boräs/Schweden

• 2,4 I Schwefelsäure (96 %-ig),

mittels Wasser auf ein Volumen von 20 I verdünnt, kontinuierlich sowie bei Einhaltung einer pro Zeiteinheit mengenmäßig 50 %-igen Progression während eines Zeitraumes von 45 Minuten zugesetzt.60 kg of a fabric made of carbonized but subsequently not neutralized wool are dyed in a tree dyeing machine by drawing out at a liquor ratio of 1:15 as follows:

• For this purpose, the dyestuff is introduced into an aqueous liquor at 40 ° C., which are used as components
• 3% of the dye Reactive Blue 19 with CI No. 61200,
• 1% of the reactive dye of the formula
  
• 1.5% of the auxiliary mixture according to Example 1, and
• 10% Glauber's salt

contains, whereupon this dye bath is circulated and heated to the dyeing temperature of 100 ° C. within 10 minutes. Then the fleet under fixation conditions is fed via an ADC 100 dosing device from ADCON AB, Boräs / Sweden

• 2.4 I sulfuric acid (96%),

diluted to a volume of 20 l with water, added continuously and with a 50% progression per unit of time over a period of 45 minutes.

After a further 20 minutes of dyeing at 100 ° C, the dyeing is complete. Then you cool the liquor and goods, rinse the latter with water and finish the dyed wool as usual.

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

Example 3

• Für diese Aufgabe wird ein wäßriges Färbebad von 60° C mit
• 5 % des Farbstoffes Reactive Black 5 mit der C.l.-Nr. 20505
• 0,5 % des Reaktivfarbstoffes der Formel
  
• 0,5 % des Reaktivfarbstoffes der Formel
  
• 1 % des Hilfsmittelgemisches gemäß Beispiel 1, und
• 10 % Glaubersalz

beschickt und zusammen mit der eingebrachten Ware im Verlauf von 15 minuten auf die Färbetemperatur von 106°C aufgeheizt. Dann beginnt man manuell mit der Säuredosierung, portionsweise in linearen Mengen nach jeweils gleichen Zeitabständen, in die unter Fixierbedingungen stehende Flotte. Dazu werden

• 5,2 Schwefelsäure (96 %-ig),

mittels Wasser auf ein Volumen von 10 I verdünnt und von dieser Lösung, welche man zweckmäßig vorwärmt, wird alle 3 Minuten jeweils 1 I dem Bad zugegeben. Nach dem letzten Säurezusatz färbt man die Ware noch weitere 20 Minuten bei der angegebenen Temperatur, und kühlt Bad samt Farbgut dann ab, spült die gefärbte Wolle mit Wasser und stellt diese wie üblich fertig.120 kg of a wool yarn that has not been finished with felt are opened on X-bobbins by dyeing them out at a liquor ratio of 1:15 to dye them real black.

• For this task, an aqueous dye bath of 60 ° C is used
• 5% of the dye Reactive Black 5 with the Cl no. 20505
• 0.5% of the reactive dye of the formula
  
• 0.5% of the reactive dye of the formula
  
• 1% of the auxiliary mixture according to Example 1, and
• 10% Glauber's salt

loaded and heated together with the goods brought to the dyeing temperature of 106 ° C over 15 minutes. Then one begins manually with the acid metering, in portions in linear amounts after the same time intervals, into the liquor under fixation conditions. To do this

• 5.2 sulfuric acid (96%),

diluted to a volume of 10 l with water and 1 l of this solution, which is appropriately preheated, is added to the bath every 3 minutes. After the last addition of acid, the goods are dyed for a further 20 minutes at the specified temperature, and then the bath and dye are cooled, the dyed wool is rinsed with water and finished as usual.

The desired real and level black dyeing of the yarn is obtained. The color of the coils is excellent.

Example 4

• Man beschickt dazu eine wäßrige Flotte von 50°C mit
• 0,5 % eines durch Umwandlung aus dem entsprechenden Farbstoff vom Vinylsulfon-Typ mit N-Methyltaurin erhaltenen Reaktivfarbstoffes der Formel
  
• 0,5 % eines durch Umwandlung aus dem entsprechenden Farbstoff von Vinylsulfon-Typ mit N-Methyltaurin erhaltenen Reaktivfarbstoffes der Formel
  
• 0,5 % eines durch Umwandlung aus dem entsprechenden Farbstoff vom Vinylsulfon-Typ mit N-Methyltaurin erhaltenen Reaktivfarbstoffes der Formel
  
• 1,5 % des Hilfsmittelgemisches gemäß Beispiel 1, und
• 10 % Glaubersalz,

heizt das Bad innerhalb von 15 Minuten auf die Färbetemperatur von 106°C auf und beginnt sofort mit der kontinuierlichen, programmgesteuerten Säuredosierung mit der Maßgabe, daß unter den genannten Temperaturbedingungen zu dieser Flotte

• 3 I Schwefelsäure (96 %-ig),

mittels Wasser auf ein Volumen von 30 I verdünnt, bei Einhaltung einer pro Zeiteinheit mengenmäßig 60 %- igen Progression während einer Zeitdauer von 45 Minuten zugesetzt werden.200 kg of a normal wool comb are dyed in the packing system by pulling them out at a liquor ratio of 1: 8:

• An aqueous liquor of 50 ° C. is charged with
• 0.5% of a reactive dye of the formula obtained by conversion from the corresponding dye of the vinyl sulfone type with N-methyl taurine
  
• 0.5% of a reactive dye of the formula obtained by conversion from the corresponding vinyl sulfone type dye with N-methyl taurine
  
• 0.5% of a reactive dye of the formula obtained by conversion from the corresponding dye of the vinyl sulfone type with N-methyl taurine
  
• 1.5% of the auxiliary mixture according to Example 1, and
• 10% Glauber's salt,

heats the bath to the dyeing temperature of 106 ° C within 15 minutes and immediately begins with the continuous, program-controlled acid metering with the proviso that under the temperature conditions mentioned to this liquor

• 3 l of sulfuric acid (96%),

diluted with water to a volume of 30 l, with 60% progression per unit of time being maintained over a period of 45 minutes.

After the metering is complete, the goods are further dyed at 106 ° C. for 10 minutes, then cooled together with the liquor, rinsed with water and finished as usual for wool.

You get a very level, brown ridge.

Example 5

• Dazu werden in einem wäßrigen Bad von 50° C
• 4 % des Reaktivfarbstoffes der Formel
  
• 0,5 % eines durch Umwandlung aus dem entsprechenden Farbstoff vom Vinylsulfon-Typ mit H-Methyltaurin erhaltenen Reaktivfarbstoffes der Formel
  
• 0,25 % des Reaktivfarbstoffes der Formel
  
• 1,5, des Hilfsmittelgemisches gemäß Beispiel 1, und
• 10 % Glaubersalz

in Lösung gebracht. Man treibt nun die Temperatur dieser Flotte im Verlauf von 10 Minuten auf 98°C (Kochtemperatur bei gegebener Höhenlage) und dosiert dann mittels eines Gerätes vom Typ ADC 100 der Firma ADCON AB, Boräs/Schweden

• 3 I Schwefelsäure (96 %-ig)

mit Wasser auf eine Volumen von 30 l verdünnt, unter Einhaltung einer pro Zeitenheit mengenmäßig 60 %- igen Progression während einer Zeitdauer von 30 Minuten bei gleichbleibender Temperatur kontinuierlich in das Färbebad ein.60 kg of a carbonized but not neutralized wool crepe fabric should be dyed by drawing out at a liquor ratio of 1:20:

• This is done in an aqueous bath at 50 ° C
• 4% of the reactive dye of the formula
  
• 0.5% of a reactive dye of the formula obtained by conversion from the corresponding dye of the vinyl sulfone type with H-methyl taurine
  
• 0.25% of the reactive dye of the formula
  
• 1.5, of the auxiliary mixture according to Example 1, and
• 10% Glauber's salt

brought into solution. The temperature of this liquor is then raised to 98 ° C. in the course of 10 minutes (cooking temperature at a given altitude) and then metered in using an ADC 100 device from ADCON AB, Boräs / Sweden

• 3 I sulfuric acid (96%)

diluted with water to a volume of 30 l, while maintaining a progression of 60% by quantity for a period of 30 minutes at a constant temperature in the dye bath.

After a further 30 minutes of dyeing at 98 ° C., the liquor is cooled by adding cold water, rinsed clear and then the dyed goods can be removed from the dyeing kettle.

A dark blue (navy) dyeing of the fabric is obtained with excellent levelness and a very nice product appearance.

Example 6

• Man setzt dafür durch Lösen in Wasser von 50°C ein wäßriges Bad enthaltend
• 1,5 % des Reaktivfarbstoffes der Formel
  
• 10 % Glaubersalz und
• 1,5 % des Hilfsmittelgemisches gemäß Beispiel 1

an und heizt es innerhalb von 10 Minuten auf 106°C auf. Sofort nach Erreichen dieser Färbetemperatur beginnt man mit dem dosierten Zusatz von

• 2,8 I Schwefelsäure (96 %-ig)

die vorher in 15 I kaltes Wasser eingegossen worden waren, in der Art, daß mittels einer Dosiervorrichtung bei Einhaltung einer pro Zeiteinheit mengenmäßig 50 %-igen Progression in insgesamt 20 Minuten die verdünnte Säure kontinuierlich der Färbeflotte zudosiert wird.In a jet dyeing machine, 70 kg of a normal wool crepe fabric with a liquor ratio of 1: 8 are to be dyed using the pull-out method.

• To do this, an aqueous bath containing water is used by dissolving in water at 50.degree
• 1.5% of the reactive dye of the formula
  
• 10% Glauber's salt and
• 1.5% of the auxiliary mixture according to Example 1

and heats it up to 106 ° C within 10 minutes. Immediately after this dyeing temperature has been reached, the metered addition of

• 2.8 l sulfuric acid (96%)

which had previously been poured into 15 l of cold water, in such a way that the diluted acid is metered continuously into the dyeing liquor in a total of 20 minutes by means of a metering device while observing a 50% progression per unit of time.

The fabric is then dyed for a further 30 minutes at 106 ° C., the liquor and the goods are then cooled, the latter is rinsed with water and the dyed goods are finally finished in the customary manner.

A brilliant orange dyeing of the wool with a high level of fastness is obtained.

Example 7

• 2 % des Reaktivfarbstoffes der Formel
  
  ersetzt und sonst genauso wie im Beispiel 6 verfahren, dann erhält man eine brillante Gelbfärbung der Wolle mit sehr guten Echtheitseigenschaften, die ohne Nachbehandlung dem Standard einer unter den herkömmlichen Bedingungen erzeugten Reaktivfärbung entsprechen.

If the dyeing operation according to the instructions of Example 6 is carried out, the dye used there is here

• 2% of the reactive dye of the formula
  
  replaced and otherwise the same procedure as in Example 6, then you get a brilliant yellow color of the wool with very good fastness properties, which correspond to the standard of a reactive dyeing produced under the conventional conditions without aftertreatment.

Claims (10)

1. A process for the level dyeing of wool or of the wool portion of fiber blends by the exhaust dyeing technique in a strongly acidic medium with aqueous liquors of reactive dyes which have in their molecule at least one grouping which, under fixing conditions, reacts with the fiber via the vinylsulfonyl form by nucleophilic addition, which comprises heating the exhaust liquor which contains such dyes of the vinylsulfonyl type and possibly all the other ingredients, but no acid or acid-donating agents required for fixing the dyes, together with the material to be dyed to the dyeing temperature within the range from 95° C to 110° C as rapidly as possible and in one step, then, on reaching the dyeing temperature and while maintaining appropriate isothermal conditions for dye fixation, adding sulfuric acid to the hot dyebath a little at a time over a prolonged period, and, dyeing the wool at pH values between 2 and 3.

2. The process as claimed in claim 1, wherein the addition of all the acid is effected discontinuously in equal portions at constant intervals.

3. The process as claimed in claim 1, wherein the addition of all the acid is effected continuously in the same amount per unit time.

4. The process as claimed in claim 1, wherein the addition of all the acid is effected discontinuously in increasing amounts at constant intervals.

5. The process as claimed in claim 1, wherein the addition of all the acid is effected continuously in an increasing amount in accordance with a certain schedule corresponding to a mathematical function.

6. The process as claimed in one or more of claims 1 to 5, wherein the addition of all the acid is effected within a period of 10 to 45 minutes.

7. The process as claimed in one or more of claims 1 to 6, wherein the treatment time of the wool at the dyeing temperature amounts to a total between 60 and 70 minutes.

8. The process as claimed in one or more of claims 1 to 7, wherein the wool is dyed with reactive dyes which, in addition to a reactive group of the vinylsulfonyl type, contain at least one monochlorotriazinyl or monofluorotriazinyl group.

9. The process as claimed in one or more of claims 1 to 8, wherein wool which has not been pretreated with an antifelting finish is dyed.

10. The process as claimed in claim 9, wherein carbonized wool which has not been subjected to prior neutralization is dyed.