EP1348800B1 - Use of alkyl benzoates as leveling agents for the dyeing of polyester fibrous materials - Google Patents

Abstract

Use is claimed as a leveling agent in textile dyeing of an agent containing 30-85 wt.% of a 1-20C alkyl benzoate.

Description

The invention relates to the use of C ₁ -C ₂₀ alkyl benzoate as a leveling agent, in particular a migrating agent, in the dyeing of polyester fiber materials.

When dyeing polyester fiber materials in particular, such as polyethylene terephthalate (PET), disperse dyes are usually added to the dye bath (dyeing aids) added to e.g. to promote an even distribution of the dyes in textiles (Leveling agent). Leveling agent that prevents the migration of the dyes in or on the textiles support are referred to as migrants. Leveling agents are generally to formulations containing nonionic and anionic dispersants, nonionic, contain emulsifying surfactants and swelling substances.

Through the use of nonionic and anionic dispersants Dye deposits on the goods avoided. The emulsifying non-ionic surfactants are both for the emulsification of the water-insoluble product components and for the even pulling of the dyes on the fiber responsible. Have great importance the swelling substances especially with regard to migration, diffusion acceleration, Migration effect, synchronization effect and affinity differences.

The swelling substances used include methyl cresotate, methyl salicylic acid, Alkyl phthalates, N-alkylphthalimides, methyl benzoates and benzoates used with di- or polyhydric alcohols. The latter benzoic acid esters are described for example in DE 32 46 383 A1 and US-A-4,516,979. In doing so aliphatic dialcohols, glycerol and pentaerythritol used as polyhydric alcohols. However, the aforementioned products have the serious disadvantages that they either are potentially teratogenic (phthalic acid esters) or smell-intensive or not very effective.

When accelerating fibers, dye accelerators are often used as aids. These are also referred to as carriers in the specialist literature. For example, C ₄ -C ₁₂ alkyl benzoates are used as carriers; they are mentioned, for example, in the aforementioned DE 32 46 383 A1 and US-A-4,516,979. Such carriers and the aforementioned leveling agents are used for completely different purposes in the dyeing of textiles. No conclusions can therefore be drawn that carriers can also be used as leveling agents.

The present invention is based on the object, one as a leveling agent, in particular as a migrating agent to provide a suitable composition which does not have the aforementioned disadvantages of known leveling agents.

According to the invention, this is achieved by using C ₁ -C ₂₀ -alkyl benzoate as leveling agent, in particular migrating agent, comprising 30% by weight to 85% by weight, in particular 40% by weight to 65% by weight, based on the agent, C ₁ -C ₂₀ alkyl benzoate. A particularly preferred C ₁ -C ₂₀ alkyl benzoate is butyl benzoate, which has proven to be very effective, in particular with regard to the migrating action.

The present invention is based on the completely surprising finding that the C ₁ -C ₂₀ alkyl benzoates, in particular butyl benzoate, which have hitherto been used for a completely different purpose, namely as a carrier, contrary to expectations, have the strongest leveling and migrating action - especially below Consideration of the price-performance ratio - show all previously known products above 125 ° C, especially 125 ° C to 135 ° C.

Carriers are dye accelerators with the aim of allowing more dye to be absorbed onto the fiber. In the case of polyesters, these act in the range between 95 ° C and 115 ° C, in which the There is a need for such an effect. Carriers have in this temperature range your optimum effect. At temperatures above 125 ° C there is no longer any carrier effect given and no longer asked.

In contrast, C ₁ -C ₂₀ alkyl benzoates hardly act as carriers in the high-temperature dyeing of polyesters (temperatures 125 ° C to 135 ° C) but have excellent leveling properties in this high-temperature range, especially with regard to migration.

A substance that works well both as a carrier at 95 ° C to 115 ° C and as a leveling agent could be used at 125 ° C to 135 ° C, was previously unknown.

Furthermore, the C ₁ -C ₂₀ -alkylbenzoates have proven to be the strongest known leveling agents of the migrating type in the range from 125 ° C. to 135 ° C.

C ₁ -C ₂₀ alkyl benzoates cause the dye to penetrate the fiber very well and very quickly and to diffuse within the fiber (migration). The result is a very good dye yield (diffusion acceleration) and, due to the increased intrafibrillary dye migration (migration effect), an excellent level coloring.

Furthermore, the synchronous diffusion will already take place during the heating and absorption phase of disperse dyes, also with different diffusion coefficients (Synchronizing effect), which benefits a level coloring.

When using C ₁ -C ₂₀ -alkyl benzoates with pronounced swelling and thus migration-promoting properties, it is particularly possible to subsequently compensate for extremely unevenly colored areas, to a certain extent by blind dyeing using the product.

Another special feature of C ₁ -C ₂₀ alkyl benzoates is the compensation or at least the weakening of material-related, ie fiber-morphology-related staining differences (affinity differences), even with large molecular weight and so-called "high energy" dyes.

Finally, the solvent character of the C ₁ -C ₂₀ -alkyl benzoates, in particular in combination with the emulsifying effect of non-ionic surfactants, also enables the raw dyeing of various processing states without separate additives.

In a preferred embodiment of the leveling agent, it also has at least one compound selected from swelling substance, non-ionic Emulsifier, anionic emulsifier and adjusting agent.

The compounds previously used for this purpose can be used as the swelling substance. The amount of the swelling substance can be 5% by weight to 70% by weight, in particular 5% by weight up to 60 wt .-%, very particularly 20 wt .-% to 40 wt .-%, based on the means according to the invention.

In a preferred embodiment, the agent has as the swelling substance an ester of C ₁ -C ₄ alkyl, C ₁ -C ₄ alkoxy, halogen such as F, Cl or Br, OH, NH ₂ and / or NO ₂ or substituted unsubstituted benzoic acid and C ₂ -C ₁₂ diol. This results in a particularly good effectiveness of the agent according to the invention with regard to the leveling and migrating effect.

If a substituted benzoic acid is used, it can contain 1 or more, e.g. 2 or 3, the have the aforementioned substituents. These can be in the o-, p- and m-positions, based on the Carboxyl group.

The alcohol component of the aforementioned benzoic acid ester is a C ₂ -C ₁₂ diol. These are aliphatic or alicyclic compounds that contain two hydroxyl groups in the molecule. For the purposes of the present invention, diols also include ether alcohols, that is to say compounds having two hydroxyl groups and additionally having 1 or more ether function (s). Examples of the C ₂ -C ₁₂ diols are glycol, diethylene glycol, propylene glycol, dipropylene glycol and butanediol. Diethylene glycol is particularly preferred because it achieves a particularly good effectiveness of the agent with regard to its properties as a leveling agent.

The degree of esterification of the benzoic acid ester is advantageously 1.0-2.0 mol of acid per Molecule diol. As a result, a particularly high aromatic content is obtained in a favorable manner, which is beneficial to the effectiveness of the agent as a leveling agent effect. Furthermore, there is, if at all, only a very small residual free content Acid is present, which minimizes the hazards caused by the caustic acid become.

In another preferred embodiment, the swelling substance is an ester of C ₁ -C ₄ alkyl, C ₁ -C ₄ alkoxy, halogen, such as F, Cl or Br, OH, NH ₂ and / or NO ₂ substituted or unsubstituted Benzoic acid and with C ₁ -C ₄ alkyl, C ₁ -C ₄ alkoxy, halogen, such as F, Cl or Br, NH ₂ and / or NO ₂ substituted or unsubstituted phenol, with 0.5 to 6 mol of alkylene oxide per Mol OH group of the phenol is implemented. These have a particularly favorable effect on the leveling and migrating effects.

For this ester, the unsubstituted or substituted one defined above is used Benzoic acid used. Alcohol component of this ester is that by the implementation of Phenols with alkylene oxide available compound. This reacts to this implementation Alkylene oxide with OH groups of the phenol, whereby new ones based on the alkylene oxide OH groups arise. The benzoic acid is bound to these. The phenol can 1 or more, for example contain 2 or 3, OH groups. In the case of several OH groups the phenol can either only 1 OH group or all OH groups with the alkylene oxide have been implemented. The phenol can be unsubstituted or as above be substituted. One or more, e.g. 2 or 3, have substituents. The Substituents can be in the o-, p- and m-positions, based on the OH group.

The phenol was substituted with the unsubstituted or substituted before the ester formation Benzoic acid is carried out, reacted with 0.5-6 moles of alkylene oxide per mole of OH group of the phenol. An alkylene oxide is understood to mean oxiranes, i.e. saturated tripartite, a Heterocyclic compounds containing oxygen atoms. You can use 2 to 6 Have carbon atoms. Examples of the alkylene oxides are ethylene oxide (EO), propylene oxide and butylene oxide. Mixtures of 2 or more alkylene oxides can also be used Reaction with the phenol can be used.

As stated above, the phenol is 0.5-6 moles derived from an alkylene oxide Units per mole of OH occupied. 0.5-1.5 mol of alkylene oxide are particularly preferred, in particular 1.2 moles of alkylene oxide. These amounts of alkylene oxide make it particularly good Preserved effectiveness of the agent as a leveling agent. In particular points the agent has a high aromatic content, which makes it particularly advantageous Interaction with polyester threads is achieved.

The degree of esterification of the benzoic acid ester is advantageously 0.3-1.0 preferred embodiment, particularly preferably 0.5-0.8, mol of acid per molecule of alcohol. This degree of esterification makes a high proportion of aromatics and therefore a special one good effectiveness of the agent as a leveling agent achieved. Furthermore, the residual free acid content is minimized, which is due to the corrosive properties of a Acid resulting hazards can also be reduced.

The esters present in the agent according to the invention can be prepared in a conventional manner are, for example by reacting the alcohol components with the benzoic acid components, for example by acid catalysis at elevated temperatures, e.g. 120-130 ° C.

In a preferred embodiment, the agent as the swelling substance can be the reaction product of a substituted by C ₁ -C ₄ alkyl, C ₁ -C ₄ alkoxy, halogen, such as F, Cl or Br, OH, NH ₂ and / or NO ₂ include unsubstituted phenol, which is reacted with 0.5 to 6 moles of alkylene oxide per mole of OH group of the phenol, as already explained in more detail above. This connection results in a particularly good effectiveness of the agent in a favorable manner.

The agent can be in addition to the ingredients described above nonionic emulsifiers, anionic emulsifiers, adjusting agents or mixtures of several of these substances. Fatty acid ethoxylates can be used as the nonionic emulsifier and / or ethoxylated vegetable or animal fats or oils are used. Both Fatty acid ethoxylates are unsaturated fatty acids with chain lengths C12-C22, occupied by for example 4-12 moles of alkylene oxide, especially ethylene oxide, are preferred. A special one preferred representative of which is oleic acid with 4-8 moles of ethylene oxide. With the oils a ethoxylated castor oil, coated with 30-60 mol ethylene oxide, preferably used. Through this Particularly good emulsification is achieved. As an anionic emulsifier come C1-C20 alkylbenzenesulfonic acids, especially dodecylbenzenesulfonic acid, and / or phosphated fatty alcohol ethoxylates (C6-C16 alkyl chain length, 2-12 mol ethylene oxide) conveniently used. A very good emulsification is achieved by this. Will one C1-C20 alkylbenzenesulfonic acid used, the amount is, for example, 1-5% by weight, based on the composition. The acidic anionic emulsifiers can with conventional bases, for example alkali hydroxide and / or alkanolamines, in particular monoethanolamine, neutralized (pH about 7). Through this neutralization is a particularly safe and easy handling of the agent according to the invention possible.

Examples of the adjusting agents are lower glycols or alcohols, such as ethylene glycol, diethylene glycol, Triethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, butyl diglycol, diacetone alcohol, Hexylene glycol, isopropanol, 4-hydroxy-4-methyl-2-pentanone or a mixture of 2 or several of these connections. By means of the positioning means, the cloudy products become clear, which is advantageous in terms of acceptance by buyers of such leveling agents.

The amount of the nonionic emulsifiers can be 5% by weight to 40% by weight, in particular approximately 25% by weight, based on the agent according to the invention. The anionic emulsifier can be present in an amount of 1% by weight to 7% by weight, based on the agent, available. 1% by weight to 12% by weight, in particular 3 % By weight to 7% by weight, based on the composition.

The rest of the agent can form water.

The agent can be produced in a particularly simple manner by the individual components are put together. This merging can be done under Stirring take place, whereby a good mixing of the components is achieved.

The agent is ideal as a leveling agent, especially a migration agent. It can contain the dye bath in amounts of 0.25 g / l to 2.0 g / l, preferably 0.5 to 1.0 g / l Ausegalisierbad in amounts of 0.5 g / l to 3.0 g / l, preferably 1.0-2.0 g / l, are added. These quantities make it particularly good in terms of economy Effectiveness of the agent as dyeing aid achieved.

The agent is ideal as a dyeing aid for Dyeing polyester, preferably polyethylene terephthalate. This is particularly good Means for high temperature dyeing of polyester fibers can be used. Such high temperature dyeing can e.g. at temperatures above 100 ° C, e.g. 125 ° C to 135 ° C, e.g. in an autoclave.

The agent can be particularly advantageous in various problem cases Dyeing of PET fiber materials and their blends with other fibers where other PET leveling agents fail or are ineffective.

• Färben unkritischer PET-Materialien jeglicher Aufmachung/Bearbeitungsform mit geringen Egalisiermittelmengen;
• Egalfärben kritischer Aufmachungsformen/Bearbeitungszustände von PET-Fasaern, wie dicht gepackte Garn- und Stückbaumwickelkörper, hoch gedrehte und oder gereckte Zwirne/Stick- und Nähgarne sowie andere technische Garne;
• Ausgleich von durch Texturier-, Verstreckungs- und Thermofixierungsschwankung verursachten kristallinitätsbedingten bzw. affinitätsbedingten Differenzen im PET-Fasermaterial jeglichen Bearbeitungszustandes und jeglicher Aufmachungsform;
• gutes nachträgliches Ausegalisieren ungleichmäßiger Färbungen von PET (allein oder in Mischung mit anderen Fasern), unabhängig von Aufmachungsform und Bearbeitungszustand, und
• simultanes Färben und Waschen von PET-Garn, Masche, Garment und Flocke, bei denen präparationsbedingte Ölauflagen vorliegen, die normalerweise ein vorgängiges Waschen oder die Mitverwendung eines separaten Wasch- und Emulgiermittels im Färbebad erfordern würden.

In particular, this composition can be used in the following processes:

• Coloring of non-critical PET materials of any make-up / processing form with small amounts of leveling agent;
• No matter the color of critical packaging / processing states of PET fibers, such as tightly packed yarn and piece tree bobbins, twisted and / or stretched threads / embroidery and sewing threads and other technical yarns;
• Compensation for differences in crystallization or affinity in the PET fiber material caused by texturing, stretching and heat setting fluctuations in any processing condition and any form of presentation;
• good subsequent leveling out of uneven colorations of PET (alone or in a mixture with other fibers), regardless of the form of presentation and processing condition, and
• Simultaneous dyeing and washing of PET yarn, stitch, garment and flake, in which there are preparation-related oil layers that would normally require prior washing or the use of a separate washing and emulsifying agent in the dye bath.

The present invention is illustrated by the following examples, without them however, restrict it.

Preparation Examples Production example 1:

60 Teile Butylbenzoat

25 Teile eines ethoxylierten Rizinusöls, belegt mit 40 Mol EO

2 Teile Dodecylbenzolsulfonsäure

7 Teile Butyldigylcol

3 Teile 4-Hydroxy-4-methyl-2-pentanon

3 Teile Monoethanolamin zur pH-Wert Einstellung (- pH 7)

100 Teile

Man erhält ein leicht gelbliches, klares Produkt.The following product is produced by mixing in a beaker:

60 parts of butyl benzoate

25 parts of an ethoxylated castor oil, coated with 40 moles of EO

2 parts of dodecylbenzenesulfonic acid

7 parts butyl digylcol

3 parts of 4-hydroxy-4-methyl-2-pentanone

3 parts monoethanolamine for pH adjustment (- pH 7)

100 parts

A slightly yellowish, clear product is obtained.

Production example 2:

65 Teile Butylbenzoat

25 Teile eines ethoxylierten Rizinusöls, belegt mit 40 Mol EO

2 Teile Dodecylbenzolsulfonsäure

7 Teile Dipropylenglycol

1 Teil Monoethanolamin zur pH-Wert Einstellung (pH - 7)

100 Teile

Man erhält ein leicht gelbliches, klares Produkt.The following product is produced by mixing in a beaker:

65 parts of butyl benzoate

25 parts of an ethoxylated castor oil, coated with 40 moles of EO

2 parts of dodecylbenzenesulfonic acid

7 parts of dipropylene glycol

1 part of monoethanolamine for pH adjustment (pH - 7)

100 parts

A slightly yellowish, clear product is obtained.

Production example 3:

40 Teile Butylbenzoat

20 Teile eines ethoxylierten Phenols (durchschnittlicher Belegungsgrad 1 Mol EO)

20 Teile eines ethoxylierten Rizinusöls, belegt mit 40 Mol EO

2 Teile Dodecylbenzolsulfonsäure

5 Teile eines ethoxylierten, phosphatierten C₆-Fettalkohols (mit 6 Mol EO)

1 Teile Monoethanolamin zur pH-Wert Einstellung (pH - 7)

12 Teile Wasser

100 Teile

Man erhält ein leicht gelbliches, klares Produkt.The following product is produced by mixing in a beaker.

40 parts of butyl benzoate

20 parts of an ethoxylated phenol (average occupancy 1 mol EO)

20 parts of an ethoxylated castor oil, coated with 40 mol EO

2 parts of dodecylbenzenesulfonic acid

5 parts of an ethoxylated, phosphated C ₆ fatty alcohol (with 6 mol EO)

1 part monoethanolamine for pH adjustment (pH - 7)

12 parts of water

100 parts

A slightly yellowish, clear product is obtained.

Production example 4:

30 Teile Butylbenzoat

30 Teile eines ethoxylierten Phenols (durchschnittlicher Belegungsgrad 1 Mol EO), mit Benzoesäure verestert.

25 Teile eines ethoxylierten Rizinusöls, belegt mit 40 Mol EO

2 Teile Dodecylbenzolsulfonsäure

7 Teile Butyldigylcol

3 Teile 4-Hydroxy-4-methyl-2-pentanon

1 Teil Monoethanolamin zur pH-Wert Einstellung (pH - 7)

2 Teile Wasser

100 Teile

Man erhält ein leicht gelbliches, klares Produkt.The following product is produced by mixing in a beaker.

30 parts of butyl benzoate

30 parts of an ethoxylated phenol (average occupancy 1 mol EO), esterified with benzoic acid.

25 parts of an ethoxylated castor oil, coated with 40 moles of EO

2 parts of dodecylbenzenesulfonic acid

7 parts butyl digylcol

3 parts of 4-hydroxy-4-methyl-2-pentanone

1 part of monoethanolamine for pH adjustment (pH - 7)

2 parts water

100 parts

A slightly yellowish, clear product is obtained.

Production example 5:

30 Teile Butylbenzoat

30 Teile Umsetzungsproduktes bestehend aus 1 Mol Diethylenglycol und 2 Mol Benzoesäure

25 Teile eines ethoxylierten Rizinusöls, belegt mit 40 Mol EO

2 Teile Dodecylbenzolsulfonsäure

7 Teile Butyldigylcol

3 Teile 4-Hydroxy-4-methyl-2-pentanon

1 Teil Monoethanolamin zur pH-Wert Einstellung (pH ∼ 7)

2 Teile Wasser

100 Teile

Man erhält ein leicht gelbliches, klares Produkt.The following product is produced by mixing in a beaker.

30 parts of butyl benzoate

30 parts of the reaction product consisting of 1 mole of diethylene glycol and 2 moles of benzoic acid

25 parts of an ethoxylated castor oil, coated with 40 moles of EO

2 parts of dodecylbenzenesulfonic acid

7 parts butyl digylcol

3 parts of 4-hydroxy-4-methyl-2-pentanone

1 part of monoethanolamine for pH adjustment (pH ∼ 7)

2 parts water

100 parts

A slightly yellowish, clear product is obtained.

Application examples: Example 6:

100 parts of a polyester lining fabric wound on perforated material carriers, previously desized, in a tree dyeing machine with a cold liquor that is 0.2 Parts of a deaerator based on emulsified polydimethylsiloxane in 800 parts Permutite water contains treated for 5 min.

1,2 Teile einer Dispersfarbstofftrichromie, bestehend aus

48 Teile Foron Gelbbraun SE-RL

22 Teile Foron Rot SE-RL

30 Teile Foron Blau SE-RL

The liquor is then heated to 50 ° C. with a maximum gradient and 0.9 parts of the agent according to the invention according to Example 1, 1.0 part of a liquid dispersant based on dodecylbenzenesulfonate and naphthalene methanesulfonate polycondensate and 1.0 part of sodium acetate are added there. The pH is then adjusted to 4.5 with acetic acid (60%) and the dye is added after a further 10 min at 50 ° C.:

1.2 parts of a disperse dye trichrome consisting of

48 parts of Foron Yellow Brown SE-RL

22 parts Foron Red SE-RL

30 parts of Foron Blau SE-RL

After a further 10 min at 50 ° C at 2 ° C / min to 100 ° C and at 1.5 ° C / min to 130 ° C heated up, stayed there for 40 min and cooled to 80 ° C. at 2 ° C./min.

The mixture is then drained off and reductively cleaned, as is known to the person skilled in the art, to obtain in this way a perfectly level and genuine coloring.

Is used instead of the product according to Example 1
0.8 parts of the product according to Example 2
you get comparably good results.

Example 7:

100 parts with the dyes Dianix Yellow HF-4G (0.15 part), Dianix Red HF-G (0.2 parts) and Dianix Blue HF-2G (0.07 parts) previously cloudy in a medium shade Circular knitwear made of polyester (PES) -Gam is on an aerodynamic Piece dyeing machine with a liquor which according to 1.0 parts of the agent according to the invention Example 1 and 1.0 part of a wrinkle inhibitor based on polyacrylamide solution in 500 parts Contains water emulsified with 0.5 ° dH, added. After heating at 3 ° C / min to 135 ° C, it stays there for 30 min and then with 2 Cooled to 100 ° C / min and further to 75 ° C at 1.5 ° C / min.

In this way, one obtains a perfect leveling out of the originally cloudy Coloring without significant change in color.

Is used instead of the product according to Example 1
1.0 parts of the product according to Example 2
you get comparably good results.

Example 8:

100 parts of a not pre-washed, stretched PES sewing thread with known (DSC-proven) Differences in drawing and consequently high risk of irregularity with a fleet containing 0.1 part of a deaerator based on Triisobutylphosphate formulation, 1.0 parts of a penetration enhancer based on a Acrylic copolymer solution, 0.5 parts of an acid buffer based on a citric acid, Formic acid and naphthalene methanesulfonate polycondensate mixture and 1.5 parts of the inventive composition according to Example 1 in 950 parts of water at 40 ° C with 2 ° dH, added.

After 10 minutes at 40 ° C., 2.1 parts of a dye trichrome are contained
25 parts of Terasil Yellow 4 G
50 parts of Terasil Red 5 G
25 parts Terasil Blau 3 RL-02 150%
added and after a further 10 min stay at 40 ° C within 25 min to 90 ° C, within 45 min to 130 ° C. There is a stay of 60 minutes.

The completion including cooling, reductive post-cleaning and post-aging, especially in The person skilled in the art is familiar with regard to minimizing oligomers and does not need any further details here Explanation.

This application gives you a perfectly colored through and no matter what color PES sewing thread. The original preparation pads are eliminated.

Is used instead of the product according to Example 1
1.5 parts of the product according to Example 2
you get comparably good results.

Example 9:

100 pieces of a PES microfibre fabric are knitted on a circular storage jet added to a liquor containing 1.5 parts of a lubricant based on a mixture Acrylic copolymer and ethoxylated caproclactam and 1.0 parts of a dispersant based Naphthalene methanesulfonate, 0.4 part of the inventive agent according to Example 1, 1.0 part a sequestering agent based on hydroxyethane diphosphonic acid, 1.0 part of sodium acetate and 0.6 parts of acetic acid 60% in 1400 parts of water containing 7 ° dH, added at 25 ° C.

After heating to 50 ° C., 0.8 parts of disperse dye trichrome are contained
37 parts foron yellow-brown RD-2RS 58 parts foron brilliant red RD-BR 05 parts foron blue RD-GLF,
added and heated up to 130 ° C at 2 ° C / min. It is left there for 30 minutes and, after cooling to 80 ° C. at 2 ° C./min, is reductively cleaned in the dye bath for 10 minutes using a specific sulfinic acid derivative.

This quick dyeing process gives a perfectly level and true dyeing.

Is used instead of the product according to Example 1
0.4 parts of the product according to Example 2
you get comparably good results.

Claims (6)

1. Use of a C₁-C₂₀-alkyl benzoate as a levelling agent for the dyeing of polyester fibre materials in a composition comprising 30% by weight to 85% by weight of the C₁-C₂₀-alkyl benzoate, based on the composition.
2. Use according to Claim 1 wherein the alkyl benzoate is butyl benzoate.
3. Use according to one of the preceding claims wherein the composition also contains at least one compound selected from a swelling substance, a nonionic emulsifier, an anionic emulsifier and an extender.
4. Use according to Claim 3 wherein the swelling substance comprises an ester of benzoic acid substituted by C₁-C₄-alkyl, C₁-C₄-alkoxy, halogen, OH, NH₂ and/or NO₂, or unsubstituted benzoic acid, with a C₂-C₁₂-diol.
5. Use according to Claim 3 wherein the swelling substance comprises an ester of benzoic acid substituted by C₁-C₄-alkyl, C₁-C₄-alkoxy, halogen, OH, NH₂ and/or NO₂, or unsubstituted benzoic acid, with phenol substituted by C₁-C₄-alkyl, C₁-C₄-alkoxy, halogen, NH₂ and/or NO₂, or unsubstituted phenol, which is reacted with 0.5 to 6 moles of alkylene oxide per mole of phenolic OH groups.
6. Use according to Claim 3 wherein the swelling substance comprises the reaction product of phenol substituted by C₁-C₄-alkyl, C₁-C₄-alkoxy, halogen, NH₂ and/or NO₂, or unsubstituted phenol, which is reacted with 0.5 to 6 moles of alkylene oxide per mole of phenolic OH groups.