Light-Fast Dyeing of Synthetic Polyamide Fibers: Anionic Dye, Oxazolo-Anilide and a Copper Complex

The present invention relates to dyed polyamide fibres having good fastness and stability to heat and light.

Good light fastness of fibres dyed with metallised acid dyes and good stability to heat and light can be obtained by treating the fibres with copper compounds. However, for certain end uses, e.g. automobile fabrics, a very high degree of fastness to light (of the dyes) and stability to light is desired.

To obtain polyamide dyeings with good light fastness and polyamide that has a good stability to light, there is provided according to the invention a process for dyeing polyamide comprising, applying to the polyamide,

a) one or more oxanilide U.V. absorbers (hereinafter defined as component a);

b) one or more copper salts and/or complexes, (hereinafter defined as component b); and

c) one or more metal-free acid dyes and/or metal complex dyes [preferably 1:2 metal complex dyes] (hereinafter defined as component c) optionally together with one or more dyeing assistants.

Preferably component b) is copper complex of a complexing agent having K.sub.MA -value of 1.5 to 20.

Preferably K.sub.MA is 1.5 to 8.

Preferably the total amount of components a) and b) present is 0.2 to 2.0% based on the weight of polyamide present.

Preferred metal complex dyes are the metallised acid dyes (preferably 1:2 metal complex dyes).

Preferred copper salts and complexes are those selected from a copper complex of .alpha.-hydroxy-C.sub.2-6 alkylene carboxylic acids, preferably those copper complexes of citric acid, gluconic acid, tartaric acid, glycollic acid and saccharic acid.

Preferred oxanilides are compounds of formula I ##STR1## in which R.sub.1 and R.sub.2 independently are selected from hydrogen, C.sub.1-12 alkyl, C.sub.1-12 alkoxy, C.sub.1-12 alkylthio, phenoxy or phenylthio; (preferably provided that R.sub.1 and R.sub.2 may not both be selected from alkylthio, phenoxy and phenylthio);

R.sub.3 is hydrogen or C.sub.1-8 alkyl; (preferably hydrogen); and

R is hydrogen or C.sub.1-12 alkyl or C.sub.1-12 alkoxy.

Preferred compounds of formula I are those of formula Ia ##STR2## in which R.sub.1a is ethoxy or methoxy;

R.sub.2a is hydrogen or C.sub.1-4 alkyl (more preferably R.sub.2a is R.sub.2a, where R.sub.2a, is hydrogen or tertiary butyl); and

R.sub.a is hydrogen or C.sub.1-4 alkyl (more preferably R.sub.a is R.sub.a, where R.sub.a, is methyl or ethyl).

Preferably R.sub.a, when C.sub.1-4 alkyl, is in an ortho position to the --NH bridging group.

Preferably R.sub.1a is in a position ortho to the --NH bridging group.

Preferably R.sub.2a, when C.sub.1-4 alkyl, is meta to the --NH bridging group and ortho to R.sub.1a.

Oxanilides of formula I are described in British Published Patent Application No. 2,085,001A and British Patent 1,234,128, the contents of which are incorporated herein by reference along with the contents of corresponding U.S. Pat. Nos. 4,412,024 and 3,906,041.

The stability constant K.sub.MA of a complexing agent with copper is described in Organic Sequestering Agents-Chaberek and Martell-John Wiley & Sons (1959) pages 297-343. These pages are incorporated herein by reference.

Preferably where a metal and complexing agent have more than one K.sub.MA -value, the K.sub.MA -value referred to in this Specification is that for the metal and the complexing agent in a medium at pH from 4 to 5.5 (preferably at a temperature of 20.degree. to 40.degree. C.).

Dyeing assistants generally used with acid dyes, such as ethoxylated alkylene diamines, for example N-behenyl-1,3-propylene-diamine 105 ethyleneoxide or ethoxylated alkylene monoamines or sulphated ethoxylated alkylene amines can be used in a process according to the invention.

Preferably component c is applied by exhaust dyeing or pad steam continuous dyeing, more preferably by exhaust dyeing in a bath having a liquor to goods ratio of 2:1 to 60:1 at an elevated temperature.

Preferably components a) and b) are applied together as an after-treatment by padding, or at the same time as the dye in the dyebath by exhaustion or by pad-steam continuous dyeing.

Preferably the temperature of an exhaust dyeing according to the invention is from 60.degree. to 135.degree. C.

Preferably the pH of the dyeing is acid, more preferably 4.0 to 7.0.

Further, according to the invention, there is provided an aqueous dispersion comprising

a) 90-20% of one or more oxanilides; and

b) 10 to 80% of one or more copper salts and/or complexes of a complexing agent having a K.sub.MA -value of 1.5 to 20, based on the total combined weights of components a) and b).

Preferred dispersions are those containing between 20 and 40%, more preferably about 30% total combined components a) and b), based on the total weight of the dispersion.

Preferably in a dispersion according to the invention 1 to 5%, more preferably about 3% of a dispersing agent, more preferably a formaldehyde naphthalene sulphonic acid condensate dispersing agent is present.

The invention will now be illustrated by the following Examples in which all percentages are by weight of substrate tested except where otherwise indicated and all temperatures are in .degree.C. The dispersions of U.V. absorber contain 3% formaldehyde naphthalene sulphonic acid condensate dispersing agent.

The following mixtures of dyes were made up:

Dye Mix 1:

1.0% of C.I. Acid Blue 80.

Dye Mix 2:

4.0% C.I. Acid Blue 280-

0.65% C.I. Acid Green 40-

Dye Mix 3:

0.14% C.I. Acid Orange 80-

0.03% C.I. Acid Red 404

0.04% C.I. Acid Black 222.

Dye Mix 4:

0.072% C.I. Acid Orange 80-

0.068% C.I. Acid Blue 193

0.04% C.I. Acid Black 222.

A 5 g sample of a nylon yarn is dyed at 100.degree. for 45 minutes in a dyebath at pH 5.5 at a liquor to goods ratio of 20:1 containing:

1% ammonium sulphate

0.5% of a commercially available behenyl-1,3propylene diamine ethoxylate; and

Dye Mix 3.

The dyed material is then padded to 67% of its weight with a 3% solution to leave on the fabric 2% (or 4.5% solution to leave 3%) by weight of the following dispersion (defined in this Example as "The Dispersion")

64% of a commercially available dispersion (30% actives) of the compound of formula 1a: ##STR3## 26.75% Gluconic acid (50%) 4.75% Cupric Chloride; and

4.50% Sodium Acetate.

"The Dispersion" is made up at pH 4.2 by dissolving the cupric chloride in gluconic acid, adding the sodium acetate which is allowed to dissolve. The dispersion of the compound of formula Ia is then added. After padding, the material is dried at 100.degree. C. and heat set for 30 seconds at 180.degree. C. Alternatively the material may be padded with dye solution containing the Dispersion and steamed for 15 minutes at atmospheric pressure followed by rinsing and drying.

Dyeings having good light fastness and fibres having good stability to light result. Further dyeings can be repeated using 2% and 3% of the Dispersion by weight of polyamide added to the bath.

The dyeings are then compared in the following light test with the dyed nylon yarn that has not been treated with the dispersion.

The dyed yarn shows the following strength loss after exposure to a HANAU SUNTEST machine for 72 hours as follows:

The loss in yarn strength shows the degree of improved stability to light of nylon yarns.

Similar results can be achieved by substituting one of Dye Mixes 1, 2 and 4 for Dye Mix 3 in the Example above.

Improvements in light fastness can be illustrated by the following results by comparison to the Grey Scale.

(a) Jaguar Test--72 hours exposure in the Hanau "Suntest" machine. (This machine has no temperature or humidity control).

(b) General Motors Test--Atlas Ci65 machine using a Borosilicate glass filter. The machine operates on alternate light and dark cycles (3.8 hours light, 1 hour dark). During the light cycle the air temperature is 65.degree. C. at 50% R.H. with a black panel temperature at 89.degree. C. During dark cycles air temperature 38.degree. C., RH 100%, the test is run until 220K. Joules radiation energy are used (about 1 week).

Example 1 is repeated using, instead of the Dispersion, Dispersion A as follows:

68.5% of the compound of formula 1a

25% gluconic acid (50%)

1.5% cupric chloride dihydrate; and

5% sodium acetate

Dye mixes 1, 3 and 4 are used and the following results occur under Test a) the Jaguar Test:

Example 1 is repeated using, instead of "The Dispersion" of Example 1, one of the dispersions below together with Dye Mix 3.

Dispersion:

64% of a dispersion in water of the compound of formula 1a

4.75% of cupric chloride

14% of citric acid;

the balance being made up with water to 100%.

Dispersion:

64% of a dispersion in water of the compound of formula 1a

4.75% of cupric chloride; and

10% of tartaric acid

the balance being made up with water to 100%.

Dispersion:

64% of a dispersion in water of the compound of formula 1a

4.75% of cupric chloride; and

7.5% of glycollic acid (70%)

the balance being made up with water to 100%.

Dispersion:

64% of a dispersion in water of the compound of formula 1a

4.75% of cupric chloride; and

15% of glycollic acid (70,)

the balance being made up with water to 100%.

Examples 2 to 5 can be repeated using any one of Dye Mixes 1, 2 or 4 in place of Dye Mix 3.

Examples 1 to 5 can be repeated using instead of the dispersion of the compound of formula 1a, the same % of a dispersion of the compound of formula 5a ##STR4##

Nylon with good stability to light as well as good light fastness properties result.