EP0146955A2 - Fast-to-sizing dyeing process for dyeings - Google Patents

Abstract

Process for the simultaneous one-bath sizing and dyeing of cellulose fibre materials with vat, sulphur vat and sulphur dyes by impregnating the cellulose fibre materials with a combined sizing-dyeing liquor which in addition to customary liquor constituents additionally contains as fastness-improving agent a reaction product of polyethyleneimine with a bifunctional alkylating agent.

Description

The present invention relates to a process for simultaneous sizing and dyeing of cellulose fiber material with vat, sulfur vat and sulfur dyes, in which the fastness of the dyeing, in particular wet fastness, can be considerably improved by adding an auxiliary agent.

In principle, colored textile fabrics can be produced in two ways, either by subjecting undyed textile fabrics to a textile dyeing process or a textile printing process, or by processing colored fiber materials into colored textile fabrics by optionally controlled weaving or knitting processes. Both manufacturing options can be used by special design of the methods for generating special effects. For example, the known denim products are produced by weaving a dyed warp yarn with undyed weft yarns.

• 1. Färben der Fasermaterialien wie Fäden oder Garne,
• 2. Schlichten der Fasermaterialien und
• 3. Verweben oder Verstricken der gefärbten und geschlichteten Fasermaterialien zu textilen Flächengebilden. Das Färben der Fasermaterialien kann nach dem Stand der Technik beispielsweise direkt auf dem Kettbaum erfolgen, wobei der gesamte Kettbaum in einem speziellen Färbeaggregat mit der Farbflotte behandelt wird. Es ist jedoch auch bekannt, daß bei Anfallen großer Metragen der Färbeprozeß kontinuierlich laufen kann. In diesem Fall werden die Garne, soweit es sich um Zellulosefasermaterial^-handelt, mit Schwefel- oder Küpenfarbstoffen oder auch beispielsweise mit Indigo auf einer Kontinuemaschine gefärbt und in der Regel auch noch im Färbeaggregat veredelt, d. h. gespült, oxidiert, gewaschen und getrocknet und daran anschließend sofort der Schlichtemaschine zugeführt.

The production of colored textile fabrics by processing colored fiber materials essentially comprises three process steps according to the prior art:

• 1. dyeing the fiber materials such as threads or yarns,
• 2. Finishing the fiber materials and
• 3. Weaving or knitting the dyed and sized fiber materials into textile fabrics. According to the prior art, the fiber materials can be dyed directly on the warp beam, the entire warp beam being treated with the dye liquor in a special dyeing unit. However, it is also known that the dyeing process can run continuously when large amounts are generated. In this case the yarns in so far as it is cellulosic fibrous material ^- is dyed with sulfur or vat dyes or else, for example, Indigo on a Kontinuemaschine and typically upgraded still in the dyeing machine, that is rinsed, oxidised, washed and dried, and thereafter immediately fed to the sizing machine .

It is known from normal dyeing processes to improve the fastness of dyeings by aftertreatment with fastness-improving agents. It would also be desirable to be able to use authenticity-improving aftertreatment agents for fast-running continuous processes in which additional washing cycles lead to a considerable increase in costs. Japanese Patent 53-44589, for example, meets this need. There, a method is proposed in which a cellulose fiber material pre-dyed with indigo is fed to a sizing liquor which, in addition to the usual sizing agents, also contains authenticity-improving agents which are intended to improve the wet fastness of the yarn dyeing. According to this publication, reaction products of polyamides obtained from saturated or unsaturated dibasic carboxylic acids with 3 to 10 carbon atoms and polyalkylene polyamine, of alkylene polyamines or polyalkylene polyamines, of diallylamine, vinyl copolymers or of polyethyleneimines with epihalohydrins are used as authenticity-improving agents.

To rationalize the manufacturing process of colored textile fabrics by processing pre-dyed yarns or threads, it has also become known to carry out the process of sizing and dyeing simultaneously and in one bath. In this case, treatment liquors are used that contain dye and sizing agent at the same time. Schwe are preferably used as dyes for this known process fur dyes, but also vat dyes. It goes without saying that the sulfur and vat dyes are added to the size dyeing liquors in the form of the water-soluble leuco forms. Under ^W single-bath "is to be understood here that in the known processes, sizing agents and coloring agents act on the fiber material at the same time. Single-bathing does not mean that dyeing and sizing must be carried out in a single trough, rather the usual sizing units have several troughs which are in the They are usually separated from one another by shorter or longer air passages, and the usual machines are designed in such a way that drinking troughs can be installed in different numbers in the manner of a modular system.

The very economical process of size dyeing, ie the simultaneous application of size and dye to the fiber material, also leads to very satisfactory dyeing results when using naphthol AS dyes, ie to dyeings with high fastness properties. When using sulfur dyes, on the other hand, the fastnesses obtained by this known process are by no means optimal; this also applies to the use of vat dyes. A particularly sensible Shortages in relatively low wet fastness properties, especially at higher loads, such as in the wash 95 ⁰ C and at the Sodakochechtheit. In order to be able to compensate for this disadvantage in a conventional manner, it would be necessary to subject the dyeing to thorough washing, but this would have the consequence in the size dyeing process that the size applied is also removed. The usual post-treatment of the dyed yarns by post-washing is thus ruled out, and the only way to achieve a satisfactory improvement in the authenticity of the manufactured goods was to obtain the sheet-like textile material obtained after the fiber materials had been woven or knitted together Subsequent cleaning. However, such an obligatory subsequent cleaning of the manufactured textile materials causes additional costs, which largely consume the savings achieved by the finishing dyeing process.

Surprisingly, it has now been found that it is possible to considerably improve the hitherto unsatisfactory fastness properties of size-dyed cellulose fiber materials by adding special authenticity-improving aids to the size-dyeing liquors in addition to size and dye. The present invention thus relates to a process for simultaneous single-bath sizing and dyeing of cellulose materials with vat, sulfur vat and sulfur dyes, in which the fastness of the dyeing, in particular critical wet fastness properties, is considerably improved by adding an auxiliary to the size-dyeing liquor.

The auxiliaries to be used according to the invention are generally added to the size dyeing liquors in amounts of 20 to 80 g per liter, preferably 30 to 60 g per liter. 4th

A higher addition of the auxiliaries is possible, but is generally not necessary, since the desired improvements in authenticity can already be achieved with the stated amounts. Higher additions are therefore uneconomical. Less than the specified additional quantities may also be sufficient in individual cases, e.g. if very light shades are colored or if there are not quite as high demands on the improvement of authenticity.

The mechanical features of the process and the apparatus used to carry out the process correspond to the known sizing or staining processes drive and the units used for this. _S o the thread material to be processed is passed in sequence through the existing troughs of the unit, then dried and fed to the stock of the processing machine. Between the impregnating troughs of the staining unit, more or less long air passages are normally switched on, the length of which is dimensioned in a known manner so that the fixing time required for the dye used is achieved. The drying of the yarn impregnated in the impregnation troughs is carried out by supplying heat, generally by means of contact heat over drying rollers, and generally leads to the dyeing process being completed and the dye being completely fixed on the substrate. The process according to the invention is now carried out in the known manner described above, it being particularly advantageous if, instead of the 3 watering troughs which are common in most units, a fourth watering trough is additionally switched on. The impregnation troughs are loaded with the sizing dye liquor in a conventional manner, the concentration of the sizing agent in the liquor being determined by the amount of the size coat required for the further processing process and the fiber quality, and the dye concentration for a given liquor intake, which is normally between 100 and 200% lies after the desired color depth. As a rule, the liquors contain 20 to 80 g per liter of sizing agent and 10 to 250 g per liter of the dye. It is advisable here to select the dye concentration in the first impregnation trough somewhat higher than in the following ones and to set the concentration of the sizing agent in the last troughs higher than in the previous ones. When using 4 drinking troughs, it is advantageous to work in the 4th drinking trough without the addition of colorants. Suitable sizing agents for the process according to the invention are all products which are customarily used, such as, for example, starch and starch derivatives, sizing agents based on carboxymethyl cellulose, vinyl homo- or copolymers, acrylate copolymers or water-soluble polyesters. The agents which are particularly suitable for cellulose materials are preferably used, in particular those based on starch and starch derivatives, carboxymethyl cellulose. Starch and starch derivatives are particularly preferred as sizing agents for the process according to the invention.

Suitable dyes for the process according to the invention are: sulfur dyes, for example the dyes specified in the "Color Index", third edition, volume 3, pages 3653-3717, the so-called sulfur vat dyes which can be found in the color index in the group of vat dyes are, for example, the hydron blue types (Vat Blue 42, 43 and 47), and vat dyes, which can be found in the "Color Index", third edition, volume 3, pages 3727-3837.

The process according to the invention is distinguished from known finishing dyeing processes in that, in addition to the usual size and coloring agents mentioned per se, it also contains special authenticity-improving agents in the soaking liquors. These agents are contained in the liquors in an amount of 20 to 80 g per liter, preferably 30 to 60 g per liter. If several troughs are used, the specified concentrations represent mean values for all troughs, whereby the difference in the concentration of the aid can be set in the individual troughs. The concentration of the auxiliary is expediently kept somewhat lower in the baths which have higher dye concentrations and a somewhat higher concentration of auxiliary is used in baths which have lower dye concentrations. The auxiliary concentrations in the first bath are preferably set between 0 and 20 g per liter, those in the last bath in the range of 20 to 80 g per liter. The fleets are supplemented with make-up fleets that contain 50% more quantities.

Reaction products of polyethyleneimine with bifunctional alkylating agents are used as auxiliaries to be used according to the invention.

worin X ein Rest der Formel

a und b unabhängig voneinander Zahlen von 0 bis 600 sind, wobei die Summe a + b eine Zahl von 50 bis 600 und c eine Zahl von 0 bis 50 ist.The polyethyleneimine required to produce the fastness improver to be used according to the invention corresponds to formula I.

wherein X is a radical of the formula

a and b are independently numbers from 0 to 600, the sum a + b being a number from 50 to 600 and c being a number from 0 to 50.

In dieser Formel bedeutet A den Rest eines alkylierenden Agens und Z entweder eine direkte Bindung oder ein zweiwertiges Brückenglied.This means that the polyethyleneimine used is a molecule in which there are -NH ₂ -, = NH- and optionally -N = units which are linked to one another by ethylene groups. In total, the polyethyleneimine contains about 50 to 600 ethyleneimine units. In conventional commercial products, primary, secondary and tertiary nitrogen functions are in a numerical ratio of about 1: 2: 1. 4 In principle, all known bifunctional alkylating agents can be used for the reaction with the ethyleneimine of the formula I. Such known bifunctional alkylating agents correspond to formula II

In this formula, A is the residue of an alkylating agent and Z is either a direct bond or a divalent bridge member.

bedeutet und Z, sofern es keine direkte Bindung ist, für einen zweiwertigen geradkettigen oder verzweigten Rest der Formel III

worin n eine Zahl von 1 bis 4 ist, einen zweiwertigen Rest der Formel IV

worin m die Zahlen 1 oder 2 bedeutet und D für -O-, -S-, -NH-, -CO-, -SO-, -SO₂- oder für Phenylen steht.Particularly suitable for the reaction with the polyethyleneimines to give auxiliaries to be used according to the invention are those bifunctional alkylating agents of the formula II in which A is a group of the formula -CH ₂ -Y, in which Y is a substituent which can be split off as an anion, in particular chlorine, bromine, iodine or -OH, or a group which can be split off as an anion, in particular the sulfato group or a sulfonyloxy group, especially phenylsulfonyloxy or p-tolylsulfonyloxy, or the epoxy group

means and Z, if it is not a direct bond, for a divalent straight-chain or branched radical of the formula III

wherein n is a number from 1 to 4, a divalent radical of the formula IV

wherein m represents the numbers 1 or 2 and D represents -O-, -S-, -NH-, -CO-, -SO-, -SO ₂ - or phenylene.

Preferred for the reaction with polyethyleneimine to auxiliaries to be used according to the invention are those bifunctional alkylating agents in which A are groups of the formula CH ₂ -Y which are linked to one another via a bridge member of the formula IV, or those in which one of the radicals A is a group of Formula is CH ₂ -Y, which is bonded directly to an epoxy group.

Examples of such bifunctional alkylating agents are epichlorohydrin, glycid, 1,3-dichloropropan-2-ol, β, β'-dichloro-diethyl ether, β, β'-dichloro-diethylamine, β, β'-dichloro-diethyl sulfide, β , β'-dichloro-diethylsulfoxide, β, β'-dichloro-diethylsulfone, β, β'-disulfatoethyl ether, β, β'-diphenylsulfonyloxyethyl ether, meta- or para-diepoxyethylbenzene, meta- or para-diepoxypropylbenzene, diepoxybutane, diepoxy-2 -methylbutane, diepoxypropylamine. To produce the aftertreatment agents to be used according to the invention, the polyethyleneimine and the bifunctional alkylating agent are reacted with one another in a weight ratio of from 100: 0.01 to 100: 2.0, preferably from 100: 0.1 to 100: 1.0.

It can be assumed that this reaction involves the installation of crosslinking bridging links between the polyethyleneimine chains. An external indication of this is that the viscosity of the aqueous solutions increases significantly when the non-crosslinked polyethyleneimine is transferred to the product crosslinked by the bifunctional alkylating agent. In principle, the polyethyleneimine can be reacted with the bifunctional alkylating agents without a solvent. In view of the better possibility of controlling the reaction and the more favorable heat dissipation, it is expedient to carry out the reaction in the presence of an inert solvent. Both organic solvents in which the reactants are soluble, such as, for example, lower alcohols, and in particular water, are suitable for this. The reaction can be carried out in the temperature range between -10 and about 100 ° C. It is particularly advantageous to carry out in the vicinity of normal room temperature, i.e. in the area between 15 and 45 ° C. This results in a reaction process with good control options, very good product quality and the lowest possible energy consumption. The reaction is essentially completed in about 1 to 2 hours.

In order to obtain auxiliaries to be used according to the invention which have particularly narrow-tolerance specifications, ie in order to achieve particularly good reproducibility of the production process, it is advantageous to after the main reaction, the reaction mixture at a defined pH between 9 and 10 for several hours, usually 2 to 6 hours, at an elevated temperature, advantageously between 60 and 100 ° C.

The use according to the invention of the aftertreatment agents thus produced leads to a considerable improvement in the wet fastness of the size dyeings. In addition, the process according to the invention results in improved sizing of the yarn through better film formation of the sizing agent. Finally, an increased weaving efficiency can also be determined.

In addition to the veined or reduced dyes, the known sizing agents and the authenticity-improving aids to be used according to the invention, the sizing dye liquors can also contain other auxiliaries and additives as are known from customary dyeing processes. In particular, it is advantageous to add known wetting and dispersing agents to the liquors in the usual concentrations. If necessary, reducing agents can also be added, which prevent reoxidation of the linked dyes.

The sulfur, sulfur vat or vat dyes are added to the size dye liquors in their reduced and thus water-soluble form. Concentrated aqueous solutions of the sulfur, sulfur vat and vat dyes made water-soluble by reduction are referred to below as stock vats, in particular in the exemplary embodiments. The production of these stumps is known in principle. It is carried out by heating aqueous dispersions of the per se water-insoluble sulfur, sulfur vat or vat dyes with reducing agents, and in the case of vat and sulfur vat dyes as a rule sodium hyposulfite ("Hydrosul fit ") and in the case of sulfur dyes sodium sulfide.

The following exemplary embodiments serve to illustrate the size dyeing process according to the invention and show the considerable improvement in the wet fastness properties of the dyeings obtained. Furthermore, the attached manufacturing examples illustrate the manufacture of the auxiliaries to be used according to the invention.

Example 1 _:

• Trog 1: 50 Gewichtsteile Hydron-Blau-Flotte 50 Gewichtsteile Schlichteflotte enthaltend 40 g/l modifizierte Stärke. Zum Flottenausgleich wird abgequetscht. Flottenaufnahme im Trog 1: 120 - 130 %.
• Trog 2: 25 Gewichtsteile der Hydron-Blau-Flotte 75 Gewichtsteile Schlichteflotte enthaltend 40 g/1 modifizierte Stärke 40 g/l Produkt des Beispiels 5. Flottenaufnahme im Trog 2: 120 - 130 %.
• Trog 3: Schlichteflotte enthaltend 40 g/1 modifizierte Stärke 60 g/1 Produkt des Beispiels 5. Flottenaufnahme im Trog 3: 100 - 120 %.

A cotton warp yarn is treated on a sizing machine with 3 troughs as follows:

• Trough 1: 50 parts by weight of hydron blue liquor 50 parts by weight of sizing liquor containing 40 g / l of modified starch. Squeeze to compensate for the fleet. Fleet intake in the trough 1: 120 - 130%.
• Trough 2: 25 parts by weight of the hydron blue liquor 75 parts by weight of sizing liquor containing 40 g / 1 modified starch 40 g / l product of Example 5.
• Trough 3: size liquor containing 40 g / 1 modified starch 60 g / 1 product of Example 5. Picking up liquor in the trough 3: 100-120%.

Das Garn läuft mit einer Geschwindigkeit von ca. 30 m/min, die Flottentemperaturen betragen im Trog 1: 80°C, im Trog 2: 80°C und im Trog 3: 80°C.The hydron blue fleet used has the following composition:

The yarn runs at a speed of approx. 30 m / min, the liquor temperatures are 1: 80 ° C in the trough, 2: 80 ° C in the trough and 3: 80 ° C in the trough.

Air ducts of approx. 20 seconds duration are switched on between the troughs. After leaving the last trough, the goods are dried.

Im Vergleich zu einem Garn, das ohne den erfindungsgemäßen Zusatz geschlichtet und gefärbt wurde, zeigt das erfindungsgemäß behandelte Garn außerdem eine verbesserte Beschlichtung des Garnes durch bessere Filmbildung des Schlichtemittels und einen gesteigerten Webnutzeffekt.The yarn thus sized shows a significant improvement in wet fastness compared to a yarn which was size-dyed without the addition of the product of Example 5, but otherwise under the same conditions.

Compared to a yarn that was sized and dyed without the additive according to the invention, the yarn treated according to the invention also shows an improved size of the yarn due to better film formation of the size and an increased weaving effect.

• 1. Waschabteil: kalt spülen + 30 ml/1 CH₃C COOH 60%ig,
• 2. Waschabteil: 40°C spülen,
• 3. Waschabteil: 40°C nachoxidieren mit Peroxid
• 4. Waschabteil: Seifen bei 80°C mit 1-3 g/l Tensid Typ Nonylphenol
• 5. Waschabteil: Seifen bei 80°C mit 1-3 g/1 Tensid, Typ Nonylphenol
• 6. Waschabteil: kalt spülen

It is advantageous to rewash the fabrics produced in this way in a wide washing machine. You work as follows:

• 1st washing compartment: rinse cold + 30 ml / 1 CH ₃ C COOH 60%,
• 2nd washing compartment: rinse at 40 ° C,
• 3. Wash compartment: reoxidize at 40 ° C with peroxide
• 4. Wash compartment: Soaps at 80 ° C with 1-3 g / l nonylphenol surfactant
• 5. Wash compartment: soaps at 80 ° C with 1-3 g / 1 surfactant, type nonylphenol
• 6. Wash compartment: rinse cold

This step improves the fastness of the dye again.

Example 2:

• Trog 1: 50 Gewichtsteile der Cassulfon Marineblau B-Flotte 50 Gewichtsteile Schlichteflotte enthaltend 40 g/l modifizierte Stärke. Flottenaufnahme im Trog 1: 140 - 160 %.
• Trog 2: 25 Gewichtsteile der Cassulfon Marineblau B-Blotte 75 Gewichtsteile Schlichteflotte enthaltend 40 g/l modifizierte Stärke 20 g/1 Produkt des Beispiels 5. Flottenaufnahme im Trog 2: 120 - 130 %.
• Trog 3: 25 Gewichtsteile der Cassulfon Marineblau B-Flotte 75 Gewichtsteile Schlichteflotte enthaltend 40 g/1 modifiziertte Stärke 40 g/l Produkt des Beispiels 5. Flottenaufnahme im Trog 3: 120 - 130 %.
• Trog 4: Schlichteflotte enthaltend 40 g/1 modifizierte Stärke 60 g/1 Produkt des Beispiels 5. Flottenaufnahme im Trog 4: 100 - 120 %.

On a sizing machine with 4 troughs, a cotton warp yarn is treated as follows:

• Trough 1: 50 parts by weight of the Cassulfon Navy Blue B-Fleet 50 parts by weight of sizing liquor containing 40 g / l modified starch. Fleet intake in the trough 1: 140-160%.
• Trough 2: 25 parts by weight of the Cassulfon navy blue B blot 75 parts by weight of size liquor containing 40 g / l modified starch 20 g / 1 product of Example 5. Picking up liquor in the trough 2: 120-130%.
• Trough 3: 25 parts by weight of the Cassulfon navy blue B liquor 75 parts by weight of sizing liquor containing 40 g / 1 modified starch 40 g / l Product of Example 5. Fleet absorption in trough 3: 120-130%.
• Trough 4: size liquor containing 40 g / 1 modified starch 60 g / 1 product of Example 5. Picking up liquor in the trough 4: 100-120%.

The yarn runs at a speed of 30 m / min, the liquor temperatures are 1: 80 ° C in the trough, 2: 85 ° C in the trough, 3: 85 ° C in the trough and 4: 85 ° C in the trough.

Recipe for the Cassulfon dye liquor: 200 g / l Cassulfon Navy Blue B are dissolved in cold water and stirred into a bath containing 1 ml / l NaOH 38 ° Be 5 ml / l Stabilisal S fl 5 ml / l sulfhydrate F 150.

Between the troughs 1, 2 and 3, air passages of 20 seconds each are switched on. The working speed can be about 30 m / min. After leaving the size-dyeing apparatus, the material to be dyed is dried and later washed and oxidized as woven goods, as described on page 13, line 7 ff.

In den obigen Beispielen kann die als Schlichte eingesetzte modifizierte Stärke auch durch Kunststoffschlichten, wie z.B. alkalilösliche PVA-Schlichte, ersetzt werden, wobei ähnliche Ergebnisse erzielt werden. Die Echtheiten können noch weiter verbessert werden, wenn nach dem Abweben nochmals eine oxidative Wäsche erfolgt.The following fastness results:

In the above examples, the modified starch used as the size can also be replaced by plastic sizes, such as, for example, alkali-soluble PVA size, with similar results being achieved. The fastness properties can be further improved if an oxidative wash is carried out again after weaving.

The following examples illustrate the production of the authenticity-enhancing aids to be used according to the invention.

Example 5:

332 ml of drinking water and 220 g (5.1 mol) of polyethyleneimine in the form of a 50% aqueous solution with an average molecular weight of 3000-5000 at 20-30 ° C. are placed in a 1 liter four-necked flask and at this temperature by adding 0 , 11 g of epichlorohydrin crosslinked. After 40 minutes, the solution is concentrated by adding H ₂ SO ₄ . adjusted to a pH of 9.5 and reheated at 90 ° C for 4 hours.

The solution is then adjusted to a concentration of 24% by adding water.

K values (measured in a 1% aqueous solution): polyethyleneimine (starting material): 39 x 10 ³ product: 50 x 10 ³ .

The examples in the following tables can be prepared in an analogous manner and used as fastness-improving aids in finishing dyeing.

Claims (9)

1. Process for simultaneous single-bath sizing and dyeing of cellulose fiber materials with vat, sulfur vat and sulfur dyes by impregnating the cellulose fiber materials with a sizing dye liquor, which, in addition to conventional sizing agents, the reduced, water-soluble forms of sulfur, sulfur vat or vat dyes and, if appropriate contains other known auxiliaries, characterized in that the size dyeing liquor additionally contains an authenticity-improving agent. 2. The method according to claim 1, characterized in that the wash dye liquor used contains the fastness-improving agent in an amount of 20 to 80 g per liter. 3. Process according to claims 1 and 2, characterized in that the sizing dye liquor used contains, as an authenticity-improving agent, a reaction product of polyethyleneimine with a bifunctional alkylating agent. 4. Process according to claims 1 to 3, characterized in that a reaction product of polyethyleneimine with epichlorohydrin, 1,3-dichloropropan-2-ol or mixtures thereof is used as the authenticity-improving agent. 5. Process according to claims 1 to 4, characterized in that a reaction product of polyethyleneimine with a bifunctional alkylating agent in a reactant weight ratio of 100: 0.01 to 100: 2 is used as an authenticity-improving agent. 6. Process according to claims 1 to 5, characterized in that a reaction product of polyethyleneimine with a bifunctional alkylating agent in a reactant weight ratio of 100: 0.1 to 100: 1.0 is used as the fastness-improving agent. 7. sizing dye liquor which, in addition to conventional sizing agents, contains the reduced, water-soluble forms of sulfur, sulfur vat or vat dyes and any known auxiliaries, characterized in that it additionally contains an authenticity-improving agent. 8. staining dye liquor according to claim 7, characterized in that it contains the fastness-improving agent in an amount of 20 to 80 g per liter. 9. sizing dye liquor according to claims 7 and 8, characterized in that the sizing dye liquor used contains, as a fastness-improving agent, a reaction product of polyethyleneimine with a functional alkylating agent.