GB1575948A

GB1575948A - Process for dyeing wool

Info

Publication number: GB1575948A
Application number: GB3373077A
Authority: GB
Original assignee: Hoechst AG
Current assignee: Hoechst AG
Priority date: 1976-08-11
Filing date: 1977-08-11
Publication date: 1980-10-01
Also published as: FR2361498B1; DE2635989C2; DE2635989B1; JPS5324491A; IT1086501B; FR2361498A1; BE857704A

Description

(54) PROCESS FOR DYEING WOOL (71) We, HOECHST AKTIEN GESELLSCHAFT, a body corporate organised according to the laws of the Federal Republic of Germany, of 6230 Frankfurt/ Main 80, Postfach 80 03 20, Federal Republic of Germanyj do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The technical information paper D 1293, published by ICI, discloses a process for dyeing wool by a pad-cold dwell method using reactive dyestuffs, according to the recommendation of the IWS (Inrernational Wool Secretariat). Furthermore, metal com- plex dyestuffs may also be used in the padcold-dwell process for dyeing wool according to P.D.Report No. 136, entitled "Further Development of the Pad-Batch-Process", which was published in April 1971 by this Secretariat.

In this known process the dyestuff fixation on the wool fibres is made possible by the addition of urea to the padding liquor in an amount of 300 g/l. The so-called "cold-dwell process", which has been reported in detail in the journal "Textilveredlung" 7 (1972), No.

1, pages 24 to 27, and disclosed in German Auslegeschrift No. 1,287,558, is based on a similar dyeing technique.

This method of dyeing of wool is generally considered to be a fibre-preserving method.

Hitherto, however, this process has not been used in practice on a large scale, because the efficiency of the dyestuffs and correspondingly the colour yield of the dyeings is not satisfactory. Moreover, some damage to' the woollen material, in spite of the use of the cold-dwelling procedure, cannot be prevented since extremely high amounts of urea must be used.

The present invention provides a process for dyeing flat textile material comprising wool fibres or a mixture of wool and synthetic fibres, which comprises padding the material with an aqueous liquor containing a reactive dyestuff and from 80 to 120 g/l of urea and having a temperature in the range of from 60 to 800C, batching up the padded material without intermediate drying, if desired or required with the application of heat to raise the temperature of the moist material to dwelling temperature, and allowing the batched up material to dwell in this state at a temperature in the range of from 750 to 85"C, generally for a period of at least from 20 minutes, preferably from 20 minutes to 4 hours, for fixation of the dyestuff.

In the process of the invention the reactive dyestuff is generally dissolved with sodium carbonate, in an amount of about 1/10 of the dyestuff weight, by boiling in water for a short time to form the padding liquor. The pH of the padding liquor is usually adjusted to a value in the range of from 5 to 6.5 by the addition of acetic acid, and the liquor may then be used for padding. The padding liquor may contain one or more auxiliaries which assist a uniform wetting of the textile material made of wool or prevent the so-called frosting effect on the wool fibres. These auxiliaries, however, do not have any influence on the dyestuff fixation. The fixation is promoted solely by the addition of urea and by adequate temperature and dwelling conditions.

In this semi-continuous process according to the invention fixation is carried out without steaming and without any further application of heat energy, but simply by allowing the padded material to dwell at a temperature in the range of from 75" to 85 C. The batchedup goods are advantageously rotated slowly during the dwelling process.

The colour intensity which may be attained on woollen material in the process of the invention is very high, and nearly reaches that obtained in an exhaustion process. It must be taken into consideration, however, that reactive dyestuffs are nearly completely exhausted in the exhaustion process, whereas in the process of the invention the dyestuff yield obtained amounts to about 90 /O of that obtained in the exhaustion process. In known pad-dwell processes only medium colour yields could be obtained. In the process of the invention extremely deep shades having very good fastness properties can be obtained with a normal dyestuff feed and, morover, the dyeing process is very simple technically and does not require considerable expenditure on apparatus.

Dyeings of deep colour intensity can be obtained by the process of the invention without using any of the conventional textile auxiliaries or additives which are, for example, used in the process described in Belgian Patent Specification No. 607,179.

Tlle colour intensity obtained is surprising and was not to be expected at all. Moreover, the dyeing method is remarkably easy and economic. Furthermore, no levelling agents have to be used.

According to the process of the invention textile material made of wool or mixtures thereof, in any suitable processing form, can be dyed very fast and deep shades, especially without any damage to the fibre, because the amounts of urea of from 80 to 120 g/l are such that damage to the fibre by urea cannot take place. The damage to the woollen fibre which is caused at urea amounts of 300 g/l in the known process is clearly demonstratable: Urea is a more or less efficient solvent for all proteins, the dissolving effect of which is higher the more the fibre properties of the woollen material have been detrimentally effected in a preceding treatment. Moreover, the complicated mechanism of a partial transformation of urea into isocyanate must be taken into consideration, since it also has a detrimental effect on the woollen fibre.

Reactive dyestuffs which may be used in the process of the invention are any of the known organic dyestuffs which are known by this term. These include mainly those dyestuffs which contain at least one group capable of reacting with polyhydroxy or polyamide fibres, a precursor to this group, or a substituent capable of reacting with polyhydroxy or polyamide fibres. As basic structures of the organic dyestuffs that may be used in the process there may be mentioned, in particular, those of the azo, anthraquinone or phthalocyanine series; the azo or phthalocyanine dyestuffs may be free from- metal or may contain metal.As examples of reactive groups, or precursors which form such reactive groups in an alkaline medium, there may be mentioned epoxy groups, the ethylene imide group, the vinyl group in the vinyl-sulfone group or in an acrylic acid radical, the p-sulfatoethyl sulfone group or the ss-chloroethyl surfone group. For the process of the invention derivatives of the tetrafluorocyclobutyl series, for example of tetrafluorocyclobutyl acrylic acid, may also be used. As reactive substituents there may be mentioned those substituents which can be split off easily to leave an electrophilic radical. Examples of such substituents are halogen atoms in quinoxaline, triazine, pyrimidine, phthalazine and pyridazone ring systems. Use may also be made of dyestuffs which contain two or more different reactive groups.

As dyestuffs for carrying out the process of the invention there may be used alternatively a dyestuff as indicated above which has previously been reacted with methyl taurine.

In this case the reactive group of the dyestuff is temporarily masked by methyl taurine.

Dyestuffs of this type are known to be suitable for dyeing wool, but only in the exhaustion process at boiling temperature or in continuous processes at a fixation temperature of from 1000 to 1200C. A process of this kind is disclosed, for example, in German Auslegeschrift No. 2,340,044.

The dyestuff efficiency in the process of the invention is optimal. The colour intensity is not improved by doubling or tripling the quantity of urea. An amount of urea of 300 g/l in the padding liquor yields the same shade and the same colour intensity as a urea amount of 100 g/l, provided that the dyeing method according to the invention is used. The use of the lower quantity of urea, however, has the advantage that the wool is not damaged while the colour intensity remains the same.

Dwelling periods of differing lengths according to the colour depth desired are advantageously applied to assure that the process is as economic as possible. Generally light shades require a dwelling period of from 20 to 60 minutes, medium shades a period of from 1 to 2 hours, and deep shades a period of from 1 to 4 hours. Navy blue shades generally require relatively long dwelling periods.

If desired a thickener may be added to the padding liquor to assist the obtention of a uniform dyestuff application.

The following Examples illustrate the invention: EXAMPLE 1.

30 g of the dyestuff of the formula

and 3 g of sodium carbonate were thoroughly dissolved in about 400 ml of hot water by boiling for half a minute. After cooling to about 700 C, 100 g of urea, in solid form, were added to the solution obtained, and also 10 g of a completely etherified non-ionic product prepared from locust bean flour (in the form of a stock solution). After complete dissolution of these additives the pH of the solution was adjusted to about 5 by adding acetic acid and the volume of the liquor was made up to 1000 ml.

A woollen fabric was padded with the liquor obtained, which had a temperature of about 65 C, with a liquor pick-up of 100% (calculated on the weight of the goods).

Thereafter the treated goods were batchedup on a roller; this batching-up process was carried out while supplying heat to raise the temperature of the batched-up goods to about 80 C without drying the goods. After dwelling for 4 hours at this temperature, the textile goods were washed out for 15 minutes with the addition of 2 ml/l of aqueous ammonia of 20% strength at a temperature of 80 C, and rinsed. There was obtained a deep, fast red dyeing.

EXAMPLES 2 to 9.

The basic process of Example 1 was carried out using the dyestuffs indicated in the following Table and with the quantity, temperature and time values stated. The shade of the resulting dyeings is indicated.

Example padding dwelling dwelling shade of No. quantity dyestuff temp. temp. time the dyeing 2 15 g/l 65 C 78 C 1 hour orange

120 g/l urea 3 30 g/l 70 C 82 C 4 hours scarlet

120 g/l urea Example padding dwelling dwelling shade of No. quantity dyestuff temp. temp. time the dyeing 4 30 g/l 75 C 80 C 4 hours scarlet

120 g/l urea 5 10 g/l 70 C 78 C 3 hours red

100 g/l urea Example padding dwelling dwelling shade of No. quantity dyestuff temp. temp. time the dyeing 6 35 g/l 70 C 80 C 4 hours yellow

120 g/l urea 7 5 g/l 65 C 80 C 2 hours light-blue

80 g/l urea Exampe padding dwelling dwelling shade of No. quantity dyestuff temp. temp. time the dyeing 8 36 g/l 65 C 78 C 4 hours blue

100 g/l urea 9 24 g/l 75 C 80 C 4 hours red

90 g/l ures WHAT WE CLAIM IS:1.A process for dyeing a flat textile material comprising wool fibres or a mixture of wool and synthetic fibres, which comprises padding the material with an aqueous liquor containing a reactive dyestuff and from 80 to 120 g/l of urea and having a temperature in the range of from 60 to 80 C, batchingup the padded material without intermediate drying, and allowing the batched-up material to dwell at a temperature in the range of from 75 to 85 C for fixation of the dyestuff.

2. A process as claimed in claim 1, wherein the batched-up material is allowed to dwell for a period of at least 20 minutes.

3. A process as claimed in claim 2, wherein the batched-up material is allowed to dwell for a period of from 20 minutes to 4 hours.

4. A process as claimed in any one of claims 1 to 3, wherein the padding liquor has a pH in the range of from 5 to 6.5.

5. A process as claimed in any one of claims 1 to 4, wherein the batched-up material is slowly rotated during dwelling.

6. A process as claimed in any one of claims 1 to 5, wherein the reactive dyestuff

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Claims

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Exampe padding dwelling dwelling shade of No. quantity dyestuff temp. temp. time the dyeing 8 36 g/l 65 C 78 C 4 hours blue

100 g/l urea 9 24 g/l 75 C 80 C 4 hours red

90 g/l ures WHAT WE CLAIM IS:1. A process for dyeing a flat textile material comprising wool fibres or a mixture of wool and synthetic fibres, which comprises padding the material with an aqueous liquor containing a reactive dyestuff and from 80 to 120 g/l of urea and having a temperature in the range of from 60 to 80 C, batchingup the padded material without intermediate drying, and allowing the batched-up material to dwell at a temperature in the range of from 75 to 85 C for fixation of the dyestuff.
2. A process as claimed in claim 1, wherein the batched-up material is allowed to dwell for a period of at least 20 minutes.
3. A process as claimed in claim 2, wherein the batched-up material is allowed to dwell for a period of from 20 minutes to 4 hours.
4. A process as claimed in any one of claims 1 to 3, wherein the padding liquor has a pH in the range of from 5 to 6.5.
5. A process as claimed in any one of claims 1 to 4, wherein the batched-up material is slowly rotated during dwelling.
6. A process as claimed in any one of claims 1 to 5, wherein the reactive dyestuff

is an azo, metallized azo, anthraquinone, phthalocyanine or metallized phthalocyanine dyestuff.
7. A process as claimed in claim 1, conducted substantially as described herein.
8. A process as claimed in claim 1, conducted substantially as described in any one of the Examples.
9. A textile material comprising wool fibres or a mixture of wool and synthetic fibres, whenever dyed by a process as claimed in any one of claims 1 to 5.