GB2225794A

GB2225794A - Vattable sulfur dye compositions

Info

Publication number: GB2225794A
Application number: GB8927649A
Authority: GB
Inventors: Rudolf Klein; Ullrich Saalfrank
Original assignee: Hoechst AG
Current assignee: Hoechst AG
Priority date: 1988-12-09
Filing date: 1989-12-07
Publication date: 1990-06-13
Also published as: DE3841481A1; GB8927649D0

Description

1 "Dyeing with sulfur dyes" The present invention relates to the dyeing of

textiles with sulfur dyes and, in particular, to processes for increasing the number of possible shades obtainable in the dyeing with sulfur dyes of textiles which consist of or contain cellulose fibers.

It is known to dye cellulose f iber textiles, or the cellulose fiber portion of blend textiles, in a continuous manner with dyes which are frequently referred to as sulfur vat dyes but which in the COLOUR INDEX are sometimes classed as vat dyes, sometimes as sulfur dyes. They have been so classified in accordance with the different application techniques recommended in the art for the dye classes in question. Nonetheless, these dyes occupy a special position within the class of C.I. Vat Dyes in that, although obtainable by the methods for C.I. Sulfur Dyes, they are applied in the same way as C.I. Vat Dyes; that is, unlike sulfur dyes, they are converted into the soluble leuco form by reduction with sodium hydroxide solution and hydrosulfite (sodium dithionite), i.e. in the same way as vat dyes, whereas sulfur dyes are usually vatted with sodium sulfide (Na, S).

For use in continuous dyeing processes, these dyes, like normal vat dyes, are prepared in a special form which ensures the fine division of the unvatted, insoluble dyes in the padding liquors of this field and their rapid, uniform reduction during the fixation step,, and hence ensures the levelness of the dyeing.

Unfortunately, the range of such sulfur vat dyes is restricted to a few shades in the blue, blackish blue and brown region. It would thus constitute an advance in the art if sulfur vat dyes, which compared with the fairly large amounts of sodium sulfide necessary for sulfur dyes 1 is are vattable by the ecologically safer combination of sodium hydroxide solution and hydrosulfite, could be more widely used.

It is also known to dye the abovementioned substrates in a continuous method with stabilized, solubilized sulfur dyes ("C.I. Solubilized Sulfur Dyes"). These dyes are chrmophores which,by introducton of a Bunte salt group (a thiosulfato group) into the reduced sulfur dye, have been watersolubilized and thus stabilized. These water-soluble compounds are therefore ideal for padding, i.e. continuous dyeing. They are customarily converted by the action of sodium sulfide during the fixation step back into the original sulfur dyes and become fixed as the latter in the fiber.

The use of such soluble sulfur dyes under the reducing action of sodium hydroxide /hydrosul f ite has only been found possible, and so disclosed, with a few products from the range of the C.I. Solubilized Sulfur Dyes. It is also known to dye the abovementioned substrates in a continuous manner with C.I. Sulfur Dyes. For this purpose, these sulfur dyes, like sulfur vat dyes, are specially worked up and usually marketed and used together with the necessary reducing agents.

It is an object of the present invention to increase the previously limited shade possibilities of the range of conventional sulfur vat dyes in order to make them suitable in this respect for wider applications. Ideally, the existing methods of dyeing this class of compounds should be changed as little as possible and their fastness level should not be reduced, so that, with the same method of dyeing,, a wider choice of colors becomes available for the articles usually dyed with these dyes.

This object is achieved according to the invention by combining sulfur vat dyes from the class of the C.I. Vat Dyes or C.I. Sulfur Dyes with selected water-solubilized sulfur dyes of the type of the C.I. Solubilized Sulfur Dyes; that is, by using them together as a heterogeneous mixture in the same padding mixture of a continuous dyeing process. in this padding liquor, the sulfur vat dyes are present as formulated, insoluble products in aqueous dispersion and the C.I. Solubilized Sulfur Dyes are present in aqueous solution.

The present invention provides a process for increasing the number of possible shades obtainable in the continuous dyeing with sulfur dyes of textiles which consist of or contain cellulose fibers, which comprises combining waterdispersed sulfur vat dyes from the class of the C.I. Vat Dyes or C.I. Sulfur Dyes with water-solubilized sulfur dyes of the type of the C.I. Solubilized Sulfur Dyes, padding this heterogeneous mixture onto the substrate from the same padding liquor, and fixing the dyes on the fiber, preferably without the presence of sulfide, by reducing with sodium hydroxide solution and hydrosulfite, then steaming and subsequently oxidizing.

The invention further provides a method of dyeing a textile material which contains cellulose fibres, comprising applying to the textile material an aqueous mixture including a sulfur vat dye and a water-solublized sulfur dye that is capable of being converted by alkali hydroxide solution and hydrosulfite into the water- soluble leuco form of the corresponding sulfur dye.

In addition the invention provides a composition for dyeing a textile material that contains cellulose fibers, comprising an aqueous mixture containing a sulfur vat dye and a water- solubilized sulfur dye selected from the C.I. Solubilized Sulfur Dyes.

is By the inclusion of C.I. Solubilized Sulfur Dyes the claimed process makes it possible to extend the shade range of the coloristically limited sulfur vat dyes into previously inaccessible regions, for example olive shades. Conversely, at the same time, C.I. Solubilized Sulfur Dyes can be shaded by means of sulfur vat dyes.

Of the sulfur vat dyes, the following are of particular interest for the process according to the invention:

C.I. Vat Blue 43 C.I. Sulfur Blue 13 C.I. Sulfur Brown 96 = C.I. No. 53630 = C.I. No. 53450 = C.I. No. 53228 Of the soluble sulfur dyes, the following are of particular interest for the process according to the invention:

C.I. Solubilized Sulfur Brown 21 C.I. Solubilized Sulfur Brown 46 C.I. Solubilized Sulfur Brown 51 = C.I. No. 53066 = C.I. No. 53016 = C.I. No. 53328 Other recommendations (with a lower color yield) for the combination shade dyeings, in question are the following:

C.I. Solubilized Sulfur Yellow 20 C.I. Solubilized Sulfur Yellow 19 C.I. Solubilized Sulfur Brown 10 C.I. No. 53056 The dyeing methods themselves may be carried out similarly to the sulfide- free procedure otherwise customary for sulfur vat dyes, i.e. in one or two baths with.

- reduction by mans of sodium hydroxide solution and hydrosulfite. The combinations of sulfur vat dyes and soluble sulfur dyes applied in the vatted state n-ey be fixed on the cellulose fiber material by steaming and subsequent 30 oxidation.

- 5 The invention will now be further described, by way of example only, with relevance to the accompanying drawing, which shows the amounts of alkali and reducing agent required as a function of dye concentration.

As mentioned above, the water-insoluble sulfur vat dyes are marketed and used in a f inely disperse form par ticularly suitable for continuous dyeing. in what fol lows, and especially in the Working Examples explained below, the sulfur vat dyes are in this commercial, formulated form.

One-bath pad-steam method:

First, the water-solubilized sulfur dyes are dissolved in warm or hot water at 50"C, and the sulfur vat dyes are sprinkled into this solution at about 30'C and dispersed therein by stirring.

The padding liquor thus prepared in general, besides wetting agents, also contains the alkalis and reducing agents required for the reduction, i.e. in the present case sodium hydroxide solution and hydrosulfite. The amounts thereof may be found in the relevant dyeing methods for sulfur vat dyes and in the drawing, since they depend on the particular dye concentrations used and on the liquor pick-up. The cloth, then, Is padded with this liquor in the cold state or at temperatures of up to 30'C, and the textile material thus treated is then steamed in saturated steam at 1010 to 1060C for 40 to 60 seconds by passing through a steamer.

After passing through the water lock of the steamer -outlet, the dyeing is finalized by first being cold rinsed with water in 3 to 4 compartments of a washer and then oxidized in 2 subsequent compartments. rinsed again with hot water (SO'C) and cold water, and if necessary soured off.

f- Two-bath pad-steam method:

The padding liquor is basically made up in the same way as for the onebath pad-steam method, except that it may have added to it, if necessary, a migration inhibitor to inhibit dye migration during the intermediary drying.

The cloth is then padded in the same way as in the one-bath process, and this padded cloth is then dried at 1000 to 1300C.

Thereafter the padded cloth is overpadded at 200 to 300C with the necessary reducing agents and a further 20 to 30 cm3/1 of the original dye liquor, and then steamed without intermediary drying at 101' to 1OCC for 40 to 60 seconds. The aftertreatment of the dyeing is the same as for the one-bath pad-steam method.

The Examples which follow further illustrate the process. The liquor pickups in % are based on the weight of dry f iber.

Example 1

A batch of mercerized cotton twill is to be dyed in an olive shade:

The padding liquor for this purpose is prepared at 250C by dissolving g of the dye C.I. Solubilized Sulfur Brown 21 (C.I. No. 53066) in water, dispersing in this solution g of the dye C.I. Sulfur Blue 13 (C.I. No. 53450) and additionally mixing this batch with g/l of a polyacrylate-based migration inhibitor and 5 g/l of an alkali- resistant wetting agent.

This liquor is used to pad the fabric to a wet pick-up of 80 %,, and the fabric is then dried at 1100C.

The pretreated fabric is then overpadded with a 250C aqueous liquor containing 66 cm3/1 of 32.5 % strength sodium hydroxide solution, 60 g/1 of hydrosulfite (commercial) and g/1 of calcined sodium carbonate, again to an 80 % wet pick-up. then steamed at 1030C for 50 seconds in a continuous steamer,, emerging from the steamer through a water lock maintained at a constant temperature of not more than WC, and finally overflowrinsed with cold water in 3 compartments of a subsequent washer.

The dye mixture is oxidized on the fabric In two subsequent compartments of the washer at 7CC with an aqueous bath containing 2 - 4 c=311 of hydrogen peroxide (35 % strength), 3 cmll of acetic acid (60 % strength) and 3 g/1 of sodium acetate x 3 H20.

The dyeing is then rinsed at 70"C with water and finalized by a subsequent cold rinse, again with water.

The result obtained is a deep olive dyeing on the twill.

Example 2

To dye a mercerized cotton twill, g/1 of the dye C.I. Solubilized Sulfur Brown 51 (C.I. No. 53328) are dissolved in 500C water, g/1 of the dye C.I. Vat Blue 43 (C.I. No. 53630) are sprinkled into this aqueous solution with stirring, and at 250C the resulting bath is then admixed with g/1 of an alkali-resistant wetting agent, 52 cm3/1 of 32.5 % strength sodium hydroxide solution, 48 g/1 of technical grade hydrosulfite and g/1 of sodium carbonate.

This liquor is then padded onto the fabric at room temperature to an 80 % wet pick-up. Thereafter the fabric is introduced into a continuous steamer, where it is steamed at 1040C in saturated steam for 60 seconds to fix the dye, and is finally removed from the steamer through the water lock at not more than 30"C. The subsequent aftertreatment of the fabric thus dyed is carried out as described in Example 1.

The result obtained is an anthracite dyeing on the cotton f abric.

j HOE 88/F 355

Claims

Claims:

A process for increasing the number of possible shades obtainable in the continuous dyeing with sulfur dyes of textiles which consist of or contain cellulose fibers, which comprises combining water-dispersed sulfur vat dyes from the class of the C.I. Vat Dyes or C.I. Sulfur Dyes with water-solubilized sulfur dyes of the type of the C.I. Solubilized Sulfur Dyes, padding this heterogeneous mixture onto the substrate from the same padding liquor, and fixing the dyes on the fiber by reducing with sodium hydroxide solution and hydrosulfite, then steaming and subsequently oxidizing.

2. The process as claimed in claim 1, wherein said dye combination is dyed by the one-bath pad-steam method.

3. The process as claimed in claim 1, wherein said dye combination is dyed by the two-bath pad-steam method.

4. The process as claimed in one or more of claims 1 to 3, wherein the sulfur vat dyes used in said dye combinations are liquid or pulverulent, dispersible preparations of:

C.I. Vat Blue 43 = C.I. No. 53630 C.I. Sulfur Blue 13 = C.I. No. 53450 C.I. Sulfur Brown 96 = C.I. No. 53228 The process as claimed in one or more of claims 1 to 3, wherein the stabilized, water-soluble sulfur dyes (Bunte salts of the reduced form thereof/leuco form) used in said dye combinations are C.I. Solubilized Sulfur Brown 21 C.I. Solubilized Sulfur Brown 46 C.I. Solubilized Sulfur Brown 51 C.I. Solubilized Sulfur Yellow 20 C.I. Solubilized Sulfur Yellow 19 C.I. Solubilized Sulfur Brown 10 = C.I. No. 53066 = C.I. No. 53016 = C.I. No. 53328 = C.I. No. 53056 - 10 6. The process as claimed in any one of claims 1 to 5, wherein substantially no sulfide is present in the reduction step.

7. A method of dyeing a textile material which contains cellulose fibres, comprising applying to the textile material an aqueous mixture including a sulfur vat dye and a water- solubilized sulfur dye that is capable of being converted by alkali hydroxide solution and hydrosulfite into the water-soluble leuco form of the corresponding sulfur dye.

8. A composition for dyeing a textile material that contains cellulose fibers, comprising an aqueous mixture containing a sulfur vat dye and a water-solubilized sulfur dye selected from the C.I. Solubilized Sulfur Dyes.

9. A method of dyeing a textile material containing cellulose fibers, comprising applying to the textile material a composition according to claim 8, and subsequently fixing the dyes on the fibers.

10. A method of dyeing a textile material substantially as described in Example 1 or Example 2 herein.

publishedlMstThePatentOffice. State House. 66,71 High Holborn.London WCIR4TP_ Further copies maybe obtainedfrom. The PatentOffice S21es Branct. St Mary Cray. Orpington. Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent. Cor.. 1'87