DE1252169B - Process for the oxidation of a sulfur dye on the goods - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

D 06 ρ

German class: 8m- 8/03

Number: 1252169

File number: P 35653IV c / 8 m

Filing date: December 10, 1964

Opened on: October 19, 1967

The invention relates to the oxidation of sulfur dyes.

Sulfur dyes generally prove to be less expensive than in many applications Vat dyes and are used extensively to make cotton goods, such as fabrics, in a Variety of tints to color, ranging from light green and blue to black. When dyeing will generally a pre-washed cotton fabric with a solution of the dye in its reduced Impregnated form, the impregnated goods are briefly steamed to prevent the dye from penetrating into the Reinforce fibers by washing excess dye away and then passing the dye through Oxidation on the goods made real.

The oxidation of reduced sulfur dyes on the goods is usually effected commercially, by briefly treating in a sodium dichromate solution acidified with acetic acid. Such Dichromate-acetic acid solutions provide dyed goods with good "light and wash fastness and wet and dry abrasion resistance, but are nevertheless deficient in various respects. The remaining Chromium salts, which are present in the dyed goods even after thorough washing, lead to a hard grip of the goods and result in strong friction with overheating and burning of needles the processing of the dyed goods on sewing machines operating at high speed, and the Oxidation waste solution is problematic in terms of its disposal.

The aqueous hydrogen peroxide could not be used as an acceptable substitute for the conventional Dichromate-acetic acid-oxidizing solutions, as many of the sulfur dyes, especially the black sulfur dyes, the oxidation of which presents the greatest difficulties while the oxidation of the commonly used aqueous hydrogen peroxide solutions from the goods are dissolved out, so that the color intensity of the treated goods is anything but satisfactory.

The present invention provides a process for the oxidation of a sulfur dye on a product, which is characterized in that the oxidation is carried out with an aqueous hydrogen peroxide solution with a pH of 5 to "9, 0.1 to 0.5 ° o and 0.5 ° ₀ contains / hydrogen peroxide at least / a water soluble salt of magnesium, calcium, strontium or barium, which is compatible with hydrogen peroxide, wherein all parts are by weight.

The oxidation can, because it takes place quickly (one process for the oxidation of a sulfur dye on the goods

Applicant:

E. I. du Pont de Nemours and Company,

Wilmington, Del. (V. St. A.)

Representative:

Dr.-Ing. W. Abitz and Dr. D. Morf,

Patent Attorneys, Munich 27, Pienzenauer Str. 28

Named as inventor:

Albert Fredenburgh Chadwick,

Wilmington, Del .;

Hugh David Terhune, Greensboro, N. C.

(V. St. A.)

Claimed priority:

V. St. v. America December 19, 1963

(331930),

dated June 5, 1964 (373 105) - -

requires only about _^1/2 to 2 minutes at room temperature), easily be carried out continuously, the residence time required by that obtained in the solution is carried out in continuous form, the present dye-impregnated product is continuously at such a speed through the peroxide solution. When carrying out such continuous work, devices known per se can be used in an effective manner, with which a strand of goods is alternately guided over and under guide rollers which are arranged alternately over and immersed in a treatment liquor. Continuous operation is preferred, but the oxidation can, of course, also be carried out batchwise, if desired.

In the present invention, transfer of the dye from the fabric to the solution during the oxidation is prevented, with the result that fully colored fabrics are obtained. In this regard, a concentration of the salt in the peroxide solution of at least about 0.5% is preferred, since much lower concentrations are generally not entirely practical. At concentrations up to 7 ° / ₀

709 678/399

3 4

effective treatment is generally obtained. here the goods at ¹ room temperature with about the

Higher concentrations can be used, equal the amount by weight of the solution of the reduced one

but do not compensate for the additional costs - dye, the impregnated goods dampen, for example

the added benefit. A concentration range 1 minute and then squeezes it onto a liquor

from about 1 to 5%, based on the weight of the 5 content, which corresponds approximately to the weight of the goods.

Solution, is particularly preferred. 'This moist, dye-impregnated product is made before

All of the oxidation experiments can be freshly prepared in the practice of the invention. as

water-soluble salts of the above-mentioned metals are blackened sulfur dyes of the trade

apply, as far as they are compared to hydrogen peroxide, those of the commercially available as »Sulfur Black, Color Index

are inert or compatible with it, e.g. both io No. 1 «known type (reaction products of 2,4-di-

Conditions of use no catalysis of a ceric nitrophenol and sodium polysulphide) used.

Settlement of the peroxide result or not under It has been shown that hydrogen peroxide solution

use of the peroxide react. Examples of suitable genes similar to those used in the following examples

Salts are the acetates, chlorides and nitrates of the same with the modification that they are not a salt

Magnesium, calcium, strontium and barium and 15 of the above metals are not effective

magnesium sulfate. Of these, the oxidation of the dye-impregnated goods will result,

four nitrates and the magnesium sulfate are preferred, but rather substantial amounts of the dye

taking the magnesium sulfate in view of its dissolving and transferring into the solutions, causing in

Overall effectiveness and its relatively low cost in each case the treated goods shade variations

is particularly preferred. The chlorides are effective (bronzing) or have poor color intensity

sam, but result in a chlorine ion introduction that has a fact. The following examples show the effective

Can cause corrosion of metal equipment. speed with which such defects are caused by the presence of the

Therefore, when carrying out the invention, metal salts are used in the peroxide solution when using the

in e.g. steel apparatuses generally eliminated with a solution under appropriate conditions

not a chloride metal salt. Examples of 25 will be.

Salts with hydrogen peroxide in the application. -I ₁

Eligibility conditions are not compatible and therefore not an example

Permanganates, sulfites and iodides are suitable. A sample of a dye-impregnated product that

of the above metals. . freshly prepared in the above manner

In order to work effectively, the 30 should travel at such a speed (about 0.9 m / min.

Concentration of hydrogen peroxide (H ₂ O ₂ ) in the = 1 yard / min.) By means of a peroxide oxidation solution

Oxidation solution amount to at least 0.1%, resulting in a dwell time in the solution

rcnd concentrations above about 0.5% avoided by one minute, and then rinsed with water,

should be, because with them the peroxide a tendency with the aqueous peroxide solution 0.18% H ₂ O ₂ and

shows adversely affecting the dye. 35 contains 0.5% CaCl ₂ and has a pH value of 3.5 (without

Concentrations of 0.15 to 0.4%, based on the setting). The color intensity of the accruing

Weight of the solution are preferred. the colored (oxidized) goods is considerable

The peroxide solution should have a pH value of 5 to worse than a corresponding sample of about 9. In the case of a dye-impregnated product exceeding about pH 5, which has a conventional acidity, no effective oxidation is obtained, 40 borrowed 1% sodium containing 1% acetic acid has been oxidized at an alkali dichromate solution exceeding about pH 9.
did not have the required amount of metal salt in solution if the same peroxide solution can be kept in stock. The previous setting of its pH value to 6.1 or 8.6 pH value of the peroxide solution is preferably 6 to 8. When an onset occurs, the color intensity and the authenticity of the pH value are necessary to keep it in To bring the active, treated goods essentially in the same area, one can use the same area as that of the goods usually oxidized with the conventional amounts of dichromate for the acetic acid solution,
add soluble acids or alkalis used,. .
whereby the use of substances such as the sodium example 2
silicates which cause precipitation of the metal cation of the 50 The procedure of Example 1 will tend to be avoided with use salt. Hydrochloric, nitric, sulfuric and acetic acid and a content of 0.18% of H ₂ O ₂ and of 2.0% are suitable sauces for a peroxide solution with a pH of 7.5 exact choice of some of the CaCl _{2 used} essentially repeated. The color intensity of the metal salt is influenced, and suitable alkalis are the same as the alkali hydroxide and ammonium hydroxide, and the authenticity of the treated goods. 55 essential of those one with the conventional

The oxidation of the dye with the peroxide-dichromate-acetic acid solution obtained goods,

solution is preferably used at a temperature of If the CaCl ₂ content is reduced to 3.0 or 5.0%

about 16 to 60 ° C (about 60 to 140 ⁰ F). increased, similar results are obtained.

Lower and higher temperatures, e.g. up to.

77 ⁰ C (170 ° F) or above, are applicable, should be 60 B e 1 s ρ 1 e 1 3

but not worth it. The procedure of example 1 is carried out with the

In the following examples, several meter changes are repeated, using a peroxide solution (several yards) of a 10.2 cm strip with a pH of 8.1, which is used in place of the washed, unbleached 2.7 mm -Cotton twill calcium chloride contains 1% magnesium sulphate (MgSO ₄ ) (3 yards) according to the conventional working method, keeps it fresh. The color intensity of the treated goods is similar to a freshly made 10% solution of a product that has been oxidized essentially to that of a black sulfur dichromate-acetic acid solution, impregnated with commercial dyes. You impregnate and the absorption capacity of the goods is the same

superior to the comparison sample (determined according to AATC 79-1954T).

Example 4

Example 3 is repeated with the modification that the pH of the peroxide solution is 5.3. The color intensity of the treated article is in borrowed Wesent _T equal to that of an oxidized with the conventional dichromate-acetic acid solution product, and its absorptivity is superior to that of the comparative sample.

Example 5

Example 4 is repeated with the modification that the peroxide solution contains 0.35% H ₂ O ₂ . The color intensity of the treated fabric is essentially the same as that of a fabric oxidized with the conventional dichromate-acetic acid solution.

Example 6

The procedure of Example 1 is repeated with the modification that a peroxide solution with a pH of 5.4 is used which contains 2% strontium nitrate [Sr (NOa) ₂ ] instead of calcium chloride. The treated color has a good absorption capacity and a good color intensity, but has a somewhat reddish hue.

Example 7

The procedure of Example 1 is repeated with the modification that a peroxide solution with a pH of 5.4 is used which contains _{2% BaCl 2} · 2H _{2 O instead of calcium chloride.} The treated goods have good absorption capacity and good color intensity, but have a somewhat reddish hue.

In a series of experiments similar to that in Example 3, peroxide solutions are used which contain magnesium sulfate (MgSO ₄ ) in concentrations of 0.049, 0.123 and 0.49%. The resulting, treated product samples show a poor color intensity and appear gray when compared with the product oxidized according to Example 3 or with a product oxidized with the conventional dichromate-acetic acid solution. The procedure of Example 3 is then repeated with the modification that 2% sodium sulfate (Na ₂ SO ₄ ) is used instead of the magnesium sulfate in the peroxide solution. The treated goods show a very bad one. Color intensity and appears gray.

In all of the above examples, the samples treated with peroxide solutions are simpler Rinse a soft handle while treated with the conventional dichromate-acetic acid solution In comparison, samples show a clearly hard handle. The one with peroxide solutions according to the invention treated, colored samples also have a good color intensity and a good light and Washfastness and color rub-off wet and dry resistance and are opposed in these relationships dyed goods that have been oxidized with the conventional dichromate-acetic acid oxidation solution are advantageous. An extraction of dye from the goods by the peroxide solutions in their

Extra use does not occur or only to a very limited extent.

All concentration figures in the description ■ expressed as a percentage relate, if not otherwise stated, based on weight.

25th

Claims (2)

Patent claims: 1. A method for oxidizing sulfur dyes on the fiber, characterized in that that the oxidation with 0.1 to 0.5 weight percent aqueous hydrogen peroxide solution, the at least 0.5 percent by weight of a non-decomposing hydrogen peroxide contains water-soluble magnesium, calcium, strontium or barium salts at pH values of 5 until 9 is carried out. 2. The method according to claim 1, characterized in that the water-soluble salt is magnesium sulfate is used. Considered publications:
German Patent No. 110 367;
Chemisches Zentralblatt, 1939, I, p. 1451 (USSR Patent No. 52,728). 709 678/399 10.67 © Bundesdruckerei Berlin