GB2117013A - Aftertreatment of cationic dyed textiles - Google Patents

Abstract

A process for dyeing a mixed wool/acrylic fibre substrate with cationic dyestuffs, comprises the step of after-treating the dyed substrate with a liquor containing a cationic fixing agent and a levelling/retarding agent haying affinity for wool dyestuffs. The fixing agent may be a condensation product of formaldehyde with an amino or imino group containing compound, which may be in salt form or a condensation product of a dicyanodiamide and formaldehyde in the presence of ammonium chloride. Examples of such agents include ethoxylated fatty amine or polyamine optionally quaternized, a quaternized ethoxylated fatty acid amido-amine, or a sulphate salt of a condensate of fatty amino alkyl amines or of a fatty amido alkyl amine with 1-200 mols. propylene oxide and 1-100 mols. ethylene oxide.

Description

SPECIFICATION Improvements in or relating to organic compounds The present invention relates to a process for dyeing mixed wool/acrylic fibre goods with cationic dystuffs, more particularly together with wool dyestuffs.

When dyeing blends of wool and acrylic fibres, particular polyacrylonitrile fibres, the cationic dyes used for the acrylic component tend to stain the wool component. This cationic staining on the wool has poor wet fastnesses.

It has been found that the wet fastnesses of the cationic dye staining on the wool component can be improved when the dyed substrate is aftertreated with a liquor containing a cationic fixing agent and a levelling/retarding agent.

More particularly, the present invention provides a process for dyeing a mixed wool/acrylic fibre substrate with cationic dyestuffs, comprising the step of after-treating the dyed substrate with a liquor containing a cationic fixing agent and a levelling/retarding agent having affinity for wool dyestuffs.

Suitable cationic fixing agents are those commonly used in paper and textile aftertreatments and include A) condensation products of formaldehyde with an amino- or imino-group-containing compound, for example, urea, thiourea, cyanamide, dicyanodiamide, diacyanodiamidine, guanidine, biguanide, biuret, melamine, aliphatic amines, and aromatic amines. Such condensation products are preferably in salt form. Examples of such compounds are described inGerman Patent No.

671,704 and British Patent 1,193,294; B) salts of condensation products of chloroparaffins with a polyethyleneimine such as one obtained from ethylene chloride and ammonia; C) salts of long chain unsaturated fatty acid residue-containing polyamines such as an ammonium salt of oleoyldiethylethylenediamine: D) long chain alkyl pyridinium compounds such as salts of cetyl and dodecylpyridinium, and E) acid- condensation products of a urea derivative with alkanolamines such as ethanolamines.

Preferred cationic fixing agents are those of type A, particularly the condensates of the aminoor imino-group containing compound or compounds and formaldehyde, optionally in the presence of an ammonium donor (e.g. urea or an ammonium salt of a mineral acid capable of splitting off ammonia).

More preferred cationic fixing agents are the condensation products of dicyanodiamide and formaldehyde in the presence of ammonium chloride; they may be formed under acid to neutral conditions by heating 7 to 1 parts by weight ammonium chloride, 8 to 25 parts dicyanodiamide with deionised water and reacting the whole with 30 to 40 parts of a 40% formaldehyde solution.

Suitable amounts of cationic fixing agent in the after-treatment liquor are 0.5 to 6%, preforably 1 to 4%, more preferably 1 to 3%, especially 2% by weight based on the weight of the substrate.

Suitable levelling-retarding agent having affinity for wool dyestuffs include known surfactant compounds commonly used as dyeing assistants, e.g. for the dyeing of wool. Preferred levelling/retarding agents are those having, in addition to their affinity for wool dyestuffs, a cationic or amphoteric character. Examples of cationic agents include addition products of alkylene oxide, e.g. ethylene oxide, propylene oxide, butylene oxide and/or styrene oxide, preferably ethylene oxide, to fatty monoamines or polyamines, fatty acid amido-alkylene-amines and bis-( 1 -hydroxy-3-alkoxy-propyl)amines, the fatty chain being saturated or unsaturated. Such compounds may optionally be quaternized.More preferred cationic levelling/retarding agents having affinity for wool dyes are ethoxylated fatty amines or polyamines, optionally quaternized, such as stearylamine, behenylamine, oleylamine or oleyl-, cetyl-, stearyl- or behenyl-amino-ethylamine or -propylamine, and quaternized ethoxylated fatty acid amido-alkylene-amines such as behenamido or stearamido-propyl-di-n-butyl-benzyl ammonium chlorise. In such compounds, the ethoxylated chain may contain from 5 to 200 ethyleneoxy units.

Preferred amphoteric levelling/retarding agents having affinity for wool dyes include: - the reaction product of ethoxylated fatty amines or polyamines with hydroxyethanesulphonic acid; - the reaction product of fatty-amino-alkylamines or -polyamines or fatty-amido-alkylamines or -polyamines with alkylene oxide (e.g.

ethylene, propylene and/or butyleneoxide) and a sulphating agent such as sulphuric acid, sulphuric chlorhydrine or sulphamic acid; - polyethyleneglycol dicarboxylic acid diester wherein one acid moiety is a saturated or unsaturated hydrocarbon residue with at least 4 carbon atoms and the second acid moiety is (C1~3) alkyl; and - polyethyleneglycol ether of polycondensates of formaldehyde with phenol derivatives such as octyl-, nonyl- or dodecyl-phenol.

More preferred amphoteric levelling/retarding agents are sulphate salts of condensates of fattyamino-alkyl-amines or fatty amido-alkyl-amines such as behenylamino or behenylamino-3propylamine, tallow-amino-, or tallow-amido-3propylamine, with propylene and ethylene oxide, preferably with 1 to 100 mols of ethylene oxide and 1 to 200 mols of propylene oxide.

The after-treatment liquor suitably contains from 20 to 60% by weight of the levelling/retarding agent based on the cationic fixing agent, preferably from 25 to 55%.

The after-treatment may be carried out by known methods for example by padding, spraying, treatment in an aqueous bath or by a continuous dipping process. Preferably the treatment is carried out in an aqueous bath. The after-treatment time may vary between 5 and 60 minutes, preferably the treatment time is approximately from 20 to 30 minutes. The bath temperature may be between room temperature and 800 C, preferably from 20 and 500 C. The treatment is carried out at a pH from 5 to 9, preferably 7 to 8.

In addition to the cationic fixing agent and the levelling/retarding agent, the after-treatment liquor may contain further additives, e.g.

solubilising agents such as ethylene glycol, urea, dispersing agents, and the like.

Suitable substrates include those comprising wool, particularly shrinkproofed wook or descaled wool, together with acrylonitrile homopolymers or copolymers, preferably polyacrylonitrile homopolymers. Preferred substrates are blends of shrinkproofed wool and polyacrylonitrile in the known ratios.

Anti-shrink treatments for wool are known and may be e.g. a treatment by chlorination under acid, neutral or alkaline conditions (followed in the latter by an acid shock treatment) and/or a treatment with resin, for example from an aqueous emulsion or an organic solvent solution, e.g. a resin based of a polyurethane containing free isocyanate groups. Preferably the wool component of the mixed substrate has been subjected to those treatments which are applied to wool intended for the IWS "Superwash" label, e.g. the Hercosett-process, Kroy-process and the like.

The process of the invention is particularly preferred for dyeing polyacrylonitrile blended with Hercosett shrinkproofed wool.

Suitable cationic dyestuffs are those known from the Colour Index and may be eg. Basic Yellow 84, Yellow 82, Orange 57, Orange 58, Bordeaux Red 14, Red 54, Red 104, Red 22, Red 59, Blue 120, Blue 77 and Blue 3.

According to a preferred embodiment of the invention, after the dyeing of the acrylic component, the substrate is further dyed (or printed), i.e. the wool component is dyed before the after-treatment with the cationic fixing agent and the levelling/retarding agent is effected.

The dyeing of the wool component may be carried out with dyestuffs known for wool dyeing, preferably reactive, acid milling or metal complex dyestuffs. Preferred acid milling dyestuffs are those having molecular weights of at least 800.

The preferred metal-complex dyestuffs are those which contain water-solubilising groups such as sulpho, carboxylic acid, aminosulphonyl and alkylsulphonyl groups, preferably at least one sulpho group. Further preferred metal complex dyestuffs are the 1:2 chromium or cobalt complexes, particularly of azo or azomethine dyestuffs.

The wool component of the mixed substrate is dyed (or printed) in accordance with known methods, e.g. in a single or two-bath process. The wool dyeing step may comprise a subsequent rinsing step.

The process according to the present invention gives dyeings with improved wet-fastnesses.

The following Examples further serve to illustrate the invention. In the Examples all parts are by weight and all temperatures in degrees Centigrade.

EXAMPLE 1 100 Parts mixed yarn comprising 50% polyacrylonitrile and 50% Hercosett shrinkproofed wool ("Superwash" finish consisting of an acid pre-chlorination followed by an after-treatment of the pre-chlorinated wool with a polyamide epichlorhydrin resin) are introduced in 2,000 parts of a dye-bath containing, per 1000 parts; 0.6 parts of the dyestuff C.l. Basic Blue 77, and 1 part sodium acetate.

The dyebath is adjusted to pH 4.5 with formic acid, heated to 50 , brought to boiling point over the course of 45 minutes and left for 30 to 45 minutes at boiling temperature. After rinsing, the dyed yarn is subsequently treated in an aqueous bath of the following composition: 1.8% by weight based on the weight of the substrate of a commercially available cationic fixing agent based on a condensation product obtained by heating 8 to 25 parts dicyanodiamide with 7 to 15 parts ammonium chloride in 60 parts of deionised water and reacting the whole with 40 parts formaldehyde 40%, as described in German Patent 671,704 Example 2), and 0.8% by weight of a commercially available levelling/retarding agent based on ethoxylated stearylamine hydrochloride (40 mols ethyleneoxide per mol stearylamine) at pH 7.5 for 20 minutes at 500.The treated yarn is then rinsed and dried.

EXAMPLE 2 100 Parts of a mixed polyacylonitrile and Hercoset shrinkproofed wool yarn as disclosed in Example 1, are introduced in 2000 parts of a bath containing 3 parts of a commercially available anti-precipitating agent, 2 parts sodium acetate and acetic acid to adjust the pH to 5. The bath is heated to 600 and, after a treatment for 1 5 minutes at 600, 1 part of the dyestuff C.l. Acid Yellow 235 is added to the bath. The dyebath is then brought to 850 over the course of 20 minutes and left circulating for 20 minutes. After addition of acetic acid to adjust the bath to pH 5, 0.6 parts of the dyestuff C.S. Basic Blue 77 are added. The bath is left circulating for 10 minutes and then heated to 980. After dyeing at boiling temperature for 60 minutes, the bath is cooled to 50 and the yarn is rinsed.

The dyed yarn is subsequently treated in a bath containing 2,000 parts of water, 1.9 parts of the cationic fixing agent of Example 1 and 0.6 parts of the levelling/retarding agent of Example 1. After a treatment for 5 minutes at 200, the bath is heated to 500 and maintained for 1 5 minutes at this temperature. The treated yarn is then rinsed and dried. A dyed yarn with good wet fastnesses is obtained.

Claims (14)

1. A process for dyeing a mixed wool/acrylic fibre substrate with cationic dyestuffs, comprising the step of after-treating the dyed substrate with a liquor containing a cationic fixing agent and a levelling/retarding agent having affinity for wool dyestuffs.

2. A process according to Claim 1, in which the cationic fixing agent is a condensation product of formaldehyde with an amino- or imino-groupcontaining compound, optionally in salt form.

3. A process according to Claim 2, in which the cationic fixing agent is a condensation product of dicyanodiamine and formaldehyde in the presence of ammonium chloride.

4. A process according to any one of the preceding claims, in which the after-treatment liquor contains from 0.6 to 6% by weight of cationic fixing agent based on the weight of the substrate.

5. A process according to any one of the preceding claims, in which the levelling/retarding agent having affinity for wool dyestuffs is cationic or amphoteric.

6. A process according to Claim 5, in which the levelling/retarding agent is an ethoxylated fatty amine or polyamine optionally quaternized, a quaternized ethoxylated fatty acid amido-amine, or a sulphate salt of a condensate of fatty-aminoalkyl-amines or of fatty-amido-alkyl-amines with 1 to 200 mols propylene oxide and 1 to 100 mols ethylene oxide.

7. A process according to Claim 6, in which the levelling/retarding agent is a fatty amine or polyamine ethoxylated with 5 to 200 mols ethylene oxide and optionally quaternized.

8. A process according to any one of the preceding claims, in which the aftertreatment liquor contains from 20 to 60% by weight of the levelling/retarding agent based on the cationic fixing agent.

9. A process according to Claim 8, in which aftertreatment liquor contains from 25 to 55% by weight of the levelling/retarding agent based on the cationic fixing agent.

10. A process according to any one of the preceding claims, in which the aftertreatment is carried out at a temperature from 20 to 500C for 5 to 60 minutes.

11. A process according to any one of the preceding claims, in which the aftertreatment step is carried out on a substrate the wool and acrylic components of which have both been dyed.

12. A process according to Claim 11, in which the wool component has been dyed with a reactive, acid milling or metal complex dyestuff.

13. A process according to any one of the preceding claims, in which the substrate comprises shrinkproofed wool and polyacrylonitrile homopolymer.

14. A process according to any one of the preceding claim substantially as hereinbefore described with reference to any one of Examples 1 and 2.

1 5. Dyed wool/acrylic fibre blends whenever obtained by a process according to any one of Claims 1 to 14.