High temperature dyeing of polyester and polyester-containing textile materials in alkaline medium

Abstract

The present invention relates to a process for the HT dyeing of polyester or polyester-containing textile materials at pH 8 to pH 11, characterized in that one or more monoazo dyes are used of the general formula I ##STR1## where X.sup.1 to X.sup.4, Y.sup.1 to R.sup.4 and R are each as defined in claim 1.

Description

The present invention relates to a process for the HT dyeing of polyester or polyester-containing textile materials.

In general, the HT dyeing of polyester or polyester-containing textile materials with disperse dyes from an aqueous dyebath within the temperature range from 120 to 140.degree. C. is carried out at a pH of 4 to 6, since a higher pH would destroy all or some of the disperse dye; colour strength is lost and shifts in hue occur, and the dyeings are not reproducible. Normally, then, polyester fibre, in a separate operation prior to dyeing, is subjected to an alkaline rinse treatment in order to remove auxiliaries which are used in weaving or spinning the fibres. These auxiliaries are for example oiling or sizing agents, the presence of which would make level dyeing of the polyester fibre difficult or impossible. The alkaline treatment is also carried out in order that oligomers on the polyester fibre, which have emerged from the inside of the fibre in the course of the dyeing process and make the dyeing appear unlevel, may be destroyed and kept in the aqueous dyeing liquor.

This alkaline rinse treatment is advantageously carried out at elevated temperature. To save time and energy and in order to reduce the number of machines required for the two processes, alkaline pretreatment and dyeing, it has always been an objective to combine the two processes in a single-bath rinsing and dyeing process. However, to achieve this objective it is necessary to develop processes which give reproducible dyeings in an aqueous dyebath at pH 8 to pH 11.

Polyester-cellulose and polyester-polyamide blend fabrics are in general dyed with disperse and reactive dyes respectively from an aqueous dyebath in two dyeing operations. As mentioned above, the disperse dyes are applied to the polyester portion at pH 4 to 6, while the reactive dyes are applied to the cellulose or polyamide portion at a pH between pH 11 and 13. Again it has been a past objective to develop a single-bath application process for the two dye classes. To this end, a search has been on for reactive dyes which dye even at a pH between 8 and 11, and here too it was necessary to have processes which ensure that under these conditions the polyester portion can be reproducibly dyed with disperse dyes.

To remedy the defects of prior art processes, German Offenlegungsschrift 3,938,631 describes a method whereby disperse dyes are dyed at a pH between pH 8 and 10 in the presence of at least one, optionally nitrogen-substituted amino acid and/or an alkali metal salt of an optionally nitrogen-substituted amino acid.

It has now been found, surprisingly, that it is possible to obtain reproducible dyeings at pH values between 8 and 11 even without the amino acid and amino acid derivative dyeing assistants described in German Offenlegungsschrift 3,938,631 if dyes of the general formula I are used.

The invention accordingly provides a process for the HT dyeing of polyester or polyester-containing textile materials at pH 8 to pH 11, characterised in that one or more monoazo dyes are used of the general formula I ##STR2## where X.sup.1 is hydrogen, chlorine, bromine, nitro or alkylsulphonyl of 1 to 4 carbon atoms,

X.sup.2 is hydrogen, chlorine or bromine, X.sup.3 is hydrogen, chlorine, bromine, nitro or alkylsulphonyl of 1 to 4 carbon atoms, X.sup.4 is hydrogen, chlorine or bromine, Y.sup.1 is hydrogen or methyl, Y.sup.2 is hydrogen, Y.sup.3 is hydrogen, Y.sup.4 is hydrogen, alkyl of 1 to 4 carbon atoms or alkoxy of 1 to 4 carbon atoms, and R is hydrogen, allyl or alkyl of 1 to 6 carbon atoms which may be substituted by alkoxy of 1 to 4 carbon atoms, and Y.sup.1, instead of denoting hydrogen or methyl, and Y.sup.2, instead of denoting hydrogen, may also be combined with the benzene ring to which they are attached to form a naphthyl radical and Y.sup.2 and Y.sup.3, instead of each denoting hydrogen, may together form a direct bond.

A preferred process according to the present invention is characterised in that there is or are used one or more monoazo dyes of the general formula Ia ##STR3## where X.sup.1 is chlorine, bromine, nitro or alkylsulphonyl of 1 to 4 carbon atoms,

X.sup.3 is chlorine, bromine, nitro or alkylsulphonyl of 1 to 4 carbon atoms, X.sup.4 is hydrogen, chlorine or bromine, and Y.sup.4 is hydrogen, alkyl of 1 to 4 carbon atoms or alkoxy of 1 to 4 carbon atoms, although X.sup.1 and X.sup.3 must not both be alkylsulphonyl of 1 to 4 carbon atoms.

A preferred process according to the present invention also includes a process where there is or are used one or more monoazo dyes of the general formula Ib ##STR4## where X.sup.1 is hydrogen, chlorine, bromine, nitro or alkylsulphonyl of 1 to 4 carbon atoms,

X.sup.2 is hydrogen, chlorine or bromine, X.sup.3 is chlorine, bromine, nitro or alkylsulphonyl of 1 to 4 carbon atoms, X.sup.4 is hydrogen, chlorine or bromine, and R is hydrogen, allyl or alkyl of 1 to 6 carbon atoms which may be substituted by alkoxy of 1 to 4 carbon atoms, although X.sup.1 and X.sup.3 must not both be alkylsulphonyl of 1 to 4 carbon atoms.

Finally, preference is also given to a dyeing process where there is or are used one or more monoazo dyes of the general formula Ic ##STR5## where X.sup.1 is hydrogen, chlorine, bromine, nitro or alkylsulphonyl of 1 to 4 carbon atoms,

X.sup.2 is hydrogen, chlorine or bromine, X.sup.3 is nitro, chlorine, bromine or alkylsulphonyl of 1 to 4 carbon atoms, X.sup.4 is hydrogen, chlorine or bromine, Y.sup.1 is hydrogen or methyl, and R is hydrogen, allyl or alkyl of 1 to 6 carbon atoms which may be substituted by alkoxy of 1 to 4 carbon atoms, although X.sup.1 and X.sup.3 must not both be alkylsulphonyl of 1 to 4 carbon atoms.

A preferred radical X.sup.2 in the dyes of the general formula I is hydrogen. Preferred radicals X.sup.3 are nitro and alkylsulphonyl of 1 to 4 carbon atoms or else chlorine and bromine when at the same time X.sup.1 is nitro or methylsulphonyl, although, when X.sup.1 is methylsulphonyl, X.sup.3 must not at the same time be alkylsulphonyl of 1 to 4 carbon atoms, and vice versa. Preferred radicals R are hydrogen, allyl or alkyl of 1 to 4 carbon atoms.

Particularly preferred dyes of the general formula Ia are those where X.sup.1 is nitro or methylsulphonyl, X.sup.3 is nitro or alkylsulphonyl of 1 to 4 carbon atoms and Y.sup.4 is hydrogen, methyl, ethyl, methoxy or ethoxy, either X.sup.1 or X.sup.3 being nitro. Very particularly preferred dyes of the general formula Ia are those where X.sup.1 is nitro, X.sup.3 is nitro, X.sup.4 is hydrogen, chlorine or bromine, and Y.sup.4 is hydrogen.

Particularly preferred dyes of the general formula Ib are those where X.sup.1 is chlorine, bromine, nitro or methylsulphonyl, X.sup.2 is hydrogen, X.sup.3 is nitro or alkylsulphonyl of 1 to 4 carbon atoms, X.sup.4 is hydrogen, and R is alkyl of 1 to 4 carbon atoms, although, when X.sup.1 is methylsulphonyl, X.sup.3 must not at the same time be alkylsulphonyl of 1 to 4 carbon atoms, and vice versa. A particularly preferred dye of the general formula Ib is the dye in which X.sup.1 is chlorine, X.sup.3 is nitro and X.sup.2, X.sup.3 and R are each hydrogen.

Particularly preferred dyes of the general formula Ic are those where X.sup.1 is chlorine, bromine, nitro or methylsulphonyl, X.sup.2 is hydrogen, X.sup.3 is nitro or alkylsulphonyl of 1 to 4 carbon atoms, X.sup.4 is hydrogen, chlorine or bromine, Y.sup.1 is hydrogen or methyl, and R is allyl or alkyl of 1 to 4 carbon atoms and in particular hydrogen, although, when X.sup.1 is methylsulphonyl, X.sup.3 must not at the same time be alkylsulphonyl of 1 to 4 carbon atoms, and vice versa.

The dyes of the general formula I are known and described for example in DE-22 12 755 and in DE-31 63 272.

The HT process according to the invention is preferably carried out in a dyeing autoclave.

The polyesters to be dyed by the process according to the invention are in particular those based on polyethylene glycol terephthalates. Polyester-containing textile materials are blends of polyester and polyamides, in particular polyester/cellulose blend fabrics.

The process according to the invention is carried out with the dyes or dye mixtures in a state of fine division. The dyes are finely divided in a conventional manner by suspending the as-synthesised dye in a liquid medium, preferably water, together with dispersants and subjecting the mixture to the action of shearing forces, which mechanically comminutes the dye particles originally present to such an extent as to produce an optimum specific surface area and keep dye sedimentation to a minimum. The particle sizes of the dyes are in general between 0.5 and 5 .mu.m, preferably about 1 .mu.m.

The dispersants used in the grinding process can be nonionic or anionic. Nonionic dispersants are for example reaction products of alkylene oxides, e.g. ethylene oxide or propylene oxide, with alkylatable compounds, for example fatty alcohols, fatty amines, fatty acids, phenols, alkylphenols and carboxamides. Anionic dispersants are for example ligninsulphonates, alkyl- or alkylarylsulphonates or alkyl-aryl-polyglycol ether sulphonates.

The dye preparations thus obtained should be pourable for most application methods. The dye and dispersant content is therefore limited in these cases. In general, the dispersions are adjusted to a dye content of up to 50% by weight and a dispersant content of up to about 25%. For economic reasons, the dye content is usually not less than 15% by weight.

The dispersions may contain further auxiliaries, for example those which act as oxidising agents, such as sodium m-nitrobenzenesulphonate, or fungicides, e.g. sodium o-phenylphenolate and sodium pentachlorophenolate.

For certain applications it is preferable to have pulverulent formulations. These powders contain the dye or the dye mixture, dispersants and other auxiliaries, for example wetting, oxidising, preserving and dustproofing agents.

A preferred method for preparing pulverulent dye preparations consists in stripping the above-described liquid dye dispersions of the liquid, for example by vacuum drying, freeze drying, drying on drum dryers, but preferably by spray drying.

To prepare dyeing liquors, the necessary amounts of dye formulations prepared as described above are diluted with the dyeing medium, preferably water, to such an extent as to produce for the dyeing a liquor ratio of from 5:1 to 50:1. The liquors are in general additionally admixed with further dyeing auxiliaries, such as dispersing, wetting and fixing auxiliaries.

The necessary dyeing liquor pH is set before or else during the dyeing by addition of bases such as alkali metal hydroxides, e.g. aqueous sodium hydroxide solution, alkali metal bicarbonates, e.g. sodium bicarbonate, or alkali metal carbonates, e.g. sodium carbonate. A preferred pH is pH 9 to 10.

To minimise pH fluctuations, it is preferable to add buffer substances as described for example in JSDC, 77 (1979), p. 47, or JSDC 79 (1981), p. 115. Particularly suitable buffer substances are those which have the greatest buffering effect in the pH range between 9 and 11. Suitable buffer systems are for example acetic acid/sodium pyrophosphate, boric acid/borax, sodium dihydrogenphosphate/disodium hydrogenphosphate, phosphoric acid/succinic acid/boric acid or combinations of organic phosphorus compounds with polycarboxylic acids. The amount of buffer system used is in general between 0.5 and 10 g/l.

The inventive concept will now be more particularly illustrated by reference to examples.

EXAMPLE 1

1.5 g of a 20% strength liquid preparation of the dye of the formula II ##STR6## are applied in a dyeing autoclave in a dyeing liquor consisting of 2 1 of water, 2 g of a dyeing auxiliary based on a formaldehyde condensation product and 5 g of a buffer substance comprising a mixture of an organic phosphorus compound and a polycarboxylic acid to 100 g of polyethylene terephthalate fabric at 130.degree. C. in the course of 45 min after the pH of the dyeing liquor has been adjusted to 9 with aqueous sodium hydroxide solution. Then the dyeing is rinsed, reduction cleared, rinsed and dried. This produces an orange dyeing.

The dyeing is repeated, except that the buffer substance used is 4 g of sodium acetate and the pH of the dyeing liquor is adjusted to 4.5 with acetic acid. The resulting orange dyeing serves as a reference material for a colorimetric comparison with the pH 9 dyeing. On this basis the colorimetric values of the pH 9 dyeing are: colour strength: 101.6%, .DELTA.H 0.02, .DELTA.C-0.33; that is, the two dyeings are virtually identical in hue and there has been virtually no decomposition of the dye at pH 9.

EXAMPLE 2

Replacing the dye of the formula II in Example 1 with 4 g of a 10% strength liquid preparation of the dye of the formula III ##STR7## buffering the dyeing liquor with a mixture of 3.6 ml of phosphoric acid, 4 g of succinic acid and 4 g of boric acid, and adjusting the dyeing liquor pH to 10 with aqueous sodium hydroxide solution likewise results in a dark brown dyeing. Compared with a dyeing carried out at pH 4.5 it has the following colorimetric values: colour strength: 101.9%, .DELTA.H-0.59, .DELTA.C 0.02. Again, there has been virtually no decomposition of the dye at the elevated pH.

EXAMPLE 3

Replacing the dye of the formula II in Example 1 with 3 g of a 10% strength liquid preparation of the dye of the formula IV ##STR8## and dyeing at pH 9.5 gives a yellowish brown dyeing which, compared with the dyeing obtained at pH 4.5, has the following colorimetric values: colour strength: 102%, .DELTA.H-0.16, .DELTA.C 0.1 and is thus likewise virtually identical in hue.

The tables which follow give further dyes which can be used in the process according to the invention.

TABLE 1______________________________________ ##STR9## Colour on poly-X.sup.1 X.sup.2 X.sup.3 X.sup.4 R Y.sup.4 ester______________________________________NO.sub.2 H NO.sub.2 H H CH.sub.3 bluish brownNO.sub.2 H NO.sub.2 H H OC.sub.2 H.sub.5 blackish brownNO.sub.2 H NO.sub.2 H H iC.sub.3 H.sub.7 greyNO.sub.2 H NO.sub.2 H CH.sub.3 H dull reddish blueNO.sub.2 H NO.sub.2 Cl H H navyNO.sub.2 H NO.sub.2 Br H H navyNO.sub.2 H NO.sub.2 Br H CH.sub.3 navyNO.sub.2 H NO.sub.2 Cl H OCH.sub.3 blueNO.sub.2 H H H H H dull scarletSO.sub.2 CH.sub.3 H NO.sub.2 H H H dull violetNO.sub.2 H SO.sub.2 nC.sub.4 H.sub.9 H H H dull violetH Cl NO.sub.2 H H H reddish brown______________________________________ TABLE 2__________________________________________________________________________ ##STR10## Colour on poly-X.sup.1 X.sup.2 X.sup.3 X.sup.4 Y.sup.1 Y.sup.2 R ester__________________________________________________________________________Cl H H Cl H H H yellowish brownCl H H Br H H H yellowish brownBr H H Br CH.sub.3 H H reddish brownCl H H Cl CH.sub.3 H H reddish brownCl H H Cl H H C.sub.2 H.sub.5 dull scarletBr H H Br H H CH.sub.2 CHCH.sub.2 reddish brownBr H H Cl H CH.sub.3 H yellowish brownNO.sub.2 H NO.sub.2 H H H H dull redSO.sub.2 CH.sub.3 H NO.sub.2 H CH.sub.3 H H scarletNO.sub.2 H Cl H H H H yellowish brownCl H NO.sub.2 H H H H orangeNO.sub.2 H NO.sub.2 Cl H H CH.sub.3 bordeauxSO.sub.2 CH.sub.3 H NO.sub.2 Br H H H bordeauxH Cl NO.sub.2 Cl H H H orangeH NO.sub.2 H H CH.sub.3 H H yellowish brownBr H NO.sub.2 Br H H (CH.sub.2).sub.2 OC.sub.2 H.sub.5 reddish brownCl H SO.sub.2 C.sub.2 H.sub.5 H H H H orangeCl H NO.sub.2 H CH.sub.3 H H redH H NO.sub.2 H CH.sub.3 H H scarlet__________________________________________________________________________ TABLE 3______________________________________ ##STR11## (Ib) Colour on poly-X.sup.1 X.sup.2 X.sup.3 X.sup.4 R ester______________________________________Cl H NO.sub.2 H C.sub.2 H.sub.5 orangeCl H NO.sub.2 H CH.sub.2 CHCH.sub.2 orangeH H NO.sub.2 H H yellowish orangeH Cl NO.sub.2 Cl H orangeNO.sub.2 H NO.sub.2 H H reddish brownNO.sub.2 H NO.sub.2 H nC.sub.4 H.sub.9 reddish brownNO.sub.2 H Cl H H yellowish orangeSO.sub.2 CH.sub.3 H NO.sub.2 H H orangeNO.sub.2 H SO.sub.2 C.sub.3 H.sub.7 H C.sub.2 H.sub.5 dull orangeH Cl NO.sub.2 H H yellowish orangeNO.sub.2 H NO.sub.2 Br CH.sub.3 dull red______________________________________

Claims

1. Process for the HT dyeing of polyester of polyester containing textile materials at pH 8 to pH 11, characterised in that one or more monoazo dyes are used of the general formula I ##STR12## where X.sup.1 is hydrogen, chlorine, bromine, nitro or alkylsulphonyl of 1 to 4 carbon atoms,

X.sup.2 is hydrogen, chlorine or bromine,

X.sup.3 is hydrogen, chlorine, bromine, nitro or alkylsulphonyl of 1 to 4 carbon atoms,

X.sup.4 is hydrogen, chlorine or bromine,

Y.sup.1 is hydrogen or methyl

Y.sup.2 is hydrogen,

Y.sup.3 is hydrogen,

Y.sup.4 is hydrogen, alkyl of 1 to 4 carbon atoms or alkoxy of 1 to 4 carbon atoms, and

R is hydrogen, allyl or alkyl of 1 to 6 carbon atoms which is optionally substituted by alkoxy of 1 to 4 carbon atoms,

and Y.sup.1, instead of denoting hydrogen or methyl, and Y.sup.2, instead of denoting hydrogen, are optionally combined with the benzene ring to which they are attached to form a naphthyl radical and Y.sup.2 and Y.sup.3, instead of each denoting hydrogen, optionally together form a direct bond.

2. Process according to claim 1, characterised in that in the general formula I X.sup.2 is hydrogen, X.sup.3 is nitro or alkylsulphonyl of 1 to 4 carbon atoms or else chlorine or bromine when at the same time X.sup.1 is nitro or methylsulphonyl, and R is hydrogen, allyl or alkyl of 1 to 4 carbon atoms, although, when X.sup.1 is methylsulphonyl, X.sup.3 must not at the same time be alkylsulphonyl of 1 to 4 carbon atoms, and vice versa.

3. Process according to claim 1, characterised in that one or more monoazo dyes are used of the general formula Ia ##STR13## where X.sup.1 is chlorine, bromine, nitro or alkylsulphonyl of 1 to 4 carbon atoms,

X.sup.3 is chlorine, bromine, nitro or alkylsulphonyl of 1 to 4 carbon atoms,

X.sup.4 is hydrogen, chlorine or bromine, and

Y.sup.4 is hydrogen, alkyl of 1 to 4 carbon atoms or alkoxy of 1 to 4 carbon atoms, although X.sup.1 and X.sup.3 must not both be alkylsulphonyl of 1 to 4 carbon atoms.

4. Process according to claim 3, characterised in that in the general formula Ia

X.sup.1 is nitro, X.sup.3 is nitro, X.sup.4 is hydrogen, chlorine or bromine, and

Y.sup.4 is hydrogen.

5. Process according to claim 1, characterised in that one or more monoazo dyes are used of the general formula Ib ##STR14## where X.sup.1 is hydrogen, chlorine, bromine, nitro or alkylsulphonyl of 1 to 4 carbon atoms,

X.sup.2 is hydrogen, chlorine or bromine,

X.sup.3 is chlorine, bromine, nitro or alkylsulphonyl of 1 to 4 carbon atoms,

X.sup.4 is hydrogen, chlorine or bromine, and

R is hydrogen, allyl or alkyl of 1 to 6 carbon atoms which is optionally substituted by alkoxy of 1 to 4 carbon atoms,

although X.sup.1 and X.sup.3 must not both be alkylsulphonyl of 1 to 4 carbon atoms.

6. Process according to claim 5, characterised in that in the general formula Ib X.sup.1 is chlorine, X.sup.3 is nitro, and X.sup.2, X.sup.3 and R are each hydrogen.

7. Process according to claim 1, characterised in that one or more monoazo dyes are used of the general formula Ic ##STR15## where X.sup.1 is hydrogen, chlorine, bromine, nitro or alkylsulphonyl of 1 to 4 carbon atoms,

X.sup.2 is hydrogen, chlorine or bromine,

X.sup.3 is chlorine, bromine, nitro or alkylsulphonyl of 1 to 4 carbon atoms,

X.sup.4 is hydrogen, chlorine or bromine,

Y.sup.1 is hydrogen or methyl, and

R is hydrogen, allyl or alkyl of 1 to 6 carbon atoms which is optionally substituted by alkoxy of 1 to 4 carbon atoms,

although X.sup.1 and X.sup.3 must not both be alkylsulphonyl of 1 to 4 carbon atoms.

8. Process according to claim 7, characterised in that in the general formula Ic

X.sup.1 is chlorine, bromine, nitro or methylsulphonyl,

X.sup.2 is hydrogen,

X.sup.3 is nitro or alkylsulphonyl of 1 to 4 carbon atoms,

X.sup.4 is hydrogen, chlorine or bromine,

Y.sup.1 is hydrogen or methyl, and

R is allyl or alkyl of 1 to 4 carbon atoms or hydrogen,

although, when X.sup.1 is methylsulphonyl, X.sup.3 must not at the same time be alkylsulphonyl of 1 to 4 carbon atoms, or vice versa.

9. Process according to claim 1, characterised in that the dyeing is carried out at pH 9 to pH 10.

10. Process according to claim 1 characterised in that the dyeing is carried out in the presence of one or more buffer substances which have a buffering effect in the particular pH range used.

11. The process according to claim 3, wherein X.sup.1 is nitro or methylsulphonyl, X.sup.3 is nitro or alkylsulphonyl of 1 to 4 carbon atoms and Y.sup.4 is hydrogen, ethyl, methoxy or ethoxy with the proviso that either X.sup.1 or X.sup.3 is nitro.

12. The process according to claim 5, wherein X.sup.1 is chlorine, bromine, nitro or methylsulphonyl, X.sup.2 is hydrogen, X.sup.3 is nitro or alkylsulphonyl of 1 to 4 carbon atoms, X.sup.4 is hydrogen and R is alkyl of 1 to 4 carbon atoms although, when X.sup.1 methylsulphonyl, X.sup.3 must not at the same time by alkylsulphonyl of 1 to 4 carbon atoms.

13. The process according to claim 1, wherein the HT process is carried out in a dyeing autoclave.

14. The process according to claim 1, wherein the polyesters to be dyed are those based on polyethylene glycol terephthalates.

15. The process according to claim 1, wherein the dyes have a particle size in general between 0.5 to 5 .mu.m.

16. The process according to claim 1, wherein the dyes have a particle size in general about 1 .mu.m.

17. The process as claimed in claim 1, wherein the dyes are finely divided by suspending the dye or the dye mixture in a liquid medium.

18. The process according to claim 17, wherein said liquid medium is water or water mixed with dispersants.

19. The process according to claim 18, wherein said dispersants are nonionic or anionic.

20. The process according to claim 17, wherein the nonionic dispersants are reaction products of ethylene oxide or propylene oxide with fatty alcohols, fatty amines, fatty acids, phenols, alkylphenols or carboxamides and the anionic dispersants are selected from the group consisting of ligninsulphonates, alkylarylsulphonates and alkyl-aryl-polyglycol ether sulphonates.