Levelling assistants are usually surface-active textile dyeing auxiliaries which have the task of thoroughly wetting the fibre/fibre mixture to be dyed, of promoting penetration of the fibres and of preventing too rapid a strike of the dyes, which can lead to unlevelness, during the dyeing process. Suitable levelling assistants are, inter alia, oil sulphonates, fatty alcohol sulphonates, fatty acid condensation products, alkyl and alkylaryl polyglycol ethers and, generally, surface-active substances.

Unlevelnesses are caused by: high and varying affinity of the dye on the fibre high and varying affinity of the fibre for the dye uneven distribution of the dye solution on the fabric temperature differences on the fabric Inadequate levelness can be avoided by suitable dyeing techniques (including improvement of the diffusion of the solution within the fabric, pH control) and by means of levelling assistants.

Levelling assistants primarily reduce the rate of dyeing, increase the rate of dye migration within the fabric and improve the compatibility of the dyes.

Levelling assistants can also have other effects which have no direct influence on the dye-fibre interactions, but nevertheless have a positive effect on the dyeing.

These include the improvement of the solubility or the dispersion stability of the dye.

Levelling assistants can exert two or more of the abovementioned effects at the same time.

Levelling assistants can be divided into two groups, those which have an affinity to the fibre, or those which have an affinity towards the dye.

Levelling assistants which have an affinity towards the dyes form an addition compound with the dye, the stability of which is dependent on the concentration and normally decreases with increasing temperature.

The dye distribution equilibrium between the dye in solution and the dye in the fibre is therefore shifted to the dye in solution. The increased dye concentration in the dye solution permits areas of the fabric which have been dyed in a non-level manner to be evened out as a result of dye migration.

Effective levelling assistants have an affinity towards the dye which is sufficient to reduce the rate of absorption or to increase the rate of migration. Differences in the absorption behaviour of different dyes can also be evened out, so that the dyes in a dye mixture strike uniformly.

Assistants with an affinity for dyes can also be used to even out materials which have already been dyed.

Assistants with an affinity towards fibres are absorbed onto the fibre in competition with the dye. This competition reaction reduces the rate of absorption and promotes the rate of migration.

Important dye-affinitive types of levelling assistants for wool are nonionic surfactants or weakly cationic, ethoxylated compounds.

Important fibre-affinitive types of levelling assistants for wool are anionic compounds.

Important dye-affinitive types of levelling assistants for polyamides are nonionic surfactants, cationic compounds or ethoxylated compounds.

Important fibre-affinitive types of levelling assistants for polyamides are cationic compounds.

Levelling assistants are preferably bought, stored and used in an aqueous composition. This presents certain problems particularly for storage. One such problem is creaming, i. e. inhomogeneties in the composition arise, which hinders use without prior treatment.

The aim of the present invention is to provide a process which permits level dyeing or printing with an assistant characterized by excellent storage stability.

Claimed is a process for dyeing or printing natural and synthetic polyamides or polyamide-containing compounds, characterized in that an assistant is used which comprises a compound of the formula (I)

in which n is 12-22, the sum a + b +1 is between 20 and 50, preferably between 30 and 40, m is 2 or 3, particularly preferably 3, o is 2-5, more preferably 2 or 3, particularly preferably 2, or mixtures thereof.

Also claimed is an assistant for dyeing or printing natural and synthetic polyamides or polyamide-containing materials which comprises a compound of the formula (I) or a mixture thereof.

A preferred assistant has the composition 20-60% of a compound of the formula (I) or a mixture thereof and 80-40% of water.

Compounds or mixtures of the formula (I) are prepared by sulphation of an amino-C2-6-alkyl- (C, 2-22) amine ethoxylate, preferably amino-C2 3-alkyl-(C, 8 22) amine ethoxylate having an average degree of ethoxylation of 20-50, preferably 30- 40, with an excess of sulphamic acid with the addition of a solubilizer, preferably 1-methyl-2-pyrrolidone.

Instead of 1-methyl-2-pyrrolidone, it is possible to use urea or dimethylformamide in particular.

Also claimed is the preparation of a storage-stable composition which comprises a compound according to formula (I) or mixtures thereof, characterized in that amino-C2-6-a) ky)- (Ci2-22) amine ethoxylate, preferably amino-C2. 3-alkyl-(C, 8 22) amine ethoxylate having an average degree of ethoxylation of 20-50, preferably 30- 40, is converted by sulphation with an excess of sulphamic acid with the addition of a solubilizer, and is diluted with water.

The examples below serve to illustrate the invention. Unless stated otherwise, the percentages are by weight, and the degrees are given in Celsius.

Example 1: 100 parts of an aminopropyl (arachidyl/behenyl) amine ethoxylate having an average degree of ethoxylation of 35 are heated to 75°C with stirring in a sulphonation flask fitted with reflux condenser. After 20 parts of sulphamic acid and 2 parts of dimethylformamide have been added, the mixture is heated to 110°C under a nitrogen atmosphere and stirred for a further 12 hours at this temperature. Following cooling to 60°C, 180 parts of demineralized water are added.

This gives a pale brown, clear solution comprising about 40% of a sulphated ethoxylated amine.

Example 2: The process is as described under Example 1, but instead of 2 parts of dimethylformamide, 2 parts of N-methylpyrrolidone are used.

Example 3: 0.5 part of sodium hydroxide is added to 50 parts of a poly (propyleneamino)- C16/C18-alkylamine, as described, for example, under CAS No. 68-911-79-5.

After the mixture has been heated to 170°C under a nitrogen atmosphere, 100 parts of ethylene oxide are then added. Following cooling to 110°C, 35 parts of urea and 35 parts of sulphamic acid are added, and the mixture is stirred for a further 12 hours at constant temperature. After cooling to 60°C, 330 parts of water are added to the mixture.

This gives a pale brown, clear solution comprising about 40% of a sulphated ethoxylated polyamine.

Application Example A A dyebath consisting of 2000 parts of water 100 parts of wool 1.0 part of the assistants according to the invention consisting of 40% of the formula (I) and 60% of water 1.5 parts of a dye mixture consisting of 85 parts of the dye C. I. Acid Red 404 and 15.0 parts of the dye C. I. Acid Red 399 and 2.0 parts of sodium acetate is adjusted to pH 4.8 using acetic acid and heated to 100°C over the course of 30 minutes. Dyeing takes place at this temperature for 30 minutes. Then, 0.8 part of an anionic naphthalenesulphonic acid/formaldehyde condensation product is slowly added to the dyebath over the course of 15 minutes. The dyeing is then cooled to 60°C, rinsed and dried.

The resulting wool dyeing has an even appearance, excellent penetration and good manufacturing and performance fastnesses.

Application Example B A dyebath consisting of 2000 parts of water 100 parts of wool 5 parts of Glauber salt, calcine 0.5 part of the assistants according to the invention consisting of 40% of the formula (I) and 60% of water 0.7 part of the dye C. I. Acid Orange 67 1.0 part of the dye C. I. Acid Red 336 and 0.5 part of the dye C. I. Acid Blue 126 is adjusted to pH 5.0 using acetic acid and heated to 100°C over the course of 30 minutes. Dyeing is carried out at this temperature for 30 minutes. Then, 0.5 part of an anionic naphthalenesulphonic acid/formaldehyde condensation product added to the dyebath over the course of 15 minutes, and dyeing is carried out for a further 5 minutes at the boiling temperature. The dyeing is then cooled to 60°C, rinsed and dried.

The resulting wool dyeing has an even appearance, good penetration and good manufacturing and performance fastnesses.

Application Example C A dyebath consisting of 2000 parts of water 100 parts of wool 10 parts of Glauber salt, calcined 0.5 part of the assistants according to the invention consisting of 40% of the formula (I) and 60% of water 0.7 part of the dye C. I. Acid Orange 67 1.0 part of the dye C. I. Acid Red 336 and 0.5 part of the dye C. I. Acid Blue 126 is adjusted to pH 4.5 using acetic acid and heated to 80°C. Dyeing is carried out at this temperature for 30 minutes. Then, 0.5 part of an anionic naphthalenesulphonic acid/formaldehyde condensation product is added to the dyebath, and dyeing is continued for a further 30 minutes. The dyeing is then cooled to 60°C, rinsed and dried.

This gives a brown level wool dyeing with good performance fastnesses and good penetration.

Application Example D 100 parts of polyamide 6 knit are introduced, at 40°C, into a dyebath consisting of 2000 parts of water 0.81 part of the dye C. I. Acid Orange 127 0.13 part of the dye C. I. Acid Red 336 and 0.10 part of the dye C. I. Acid Blue 350 100 parts of wool 2.0 parts of the assistants according to the invention consisting of 40% of the formula (I) and 60% of water.

The dyebath is heated to 98°C over the course of 30 minutes. Following a migration phase of 30 minutes at 98°C, 0.5 part of an anionic naphthalenesulphonic acid/formaldehyde condensation product is metered into the dyebath over the course of 20 minutes. After further dyeing at 98°C over the course of 10 minutes, the dyebath is cooled to 80°C over the course of 20 minutes, and the knit is rinsed and dried.

This gives an orange coloration with good penetration of the fibre intersections coupled with complete bath exhaustion.