US2628883A - Continuous chrome mordanting and dyeing of wool - Google Patents

Description

Feb. 17, 1953 J. N. 'DALTON ETAL 2,628,383

CONTINUOUS CHROME MORDANTING AND DYEING OF WOOL Filed Nov. 23, 1949 lA/l/E/V 7'055' JO NMDALTOM Jam/PP 11511055 ATToR/vEV contrasted which have become available, such as the meta- Patented Feb. 17, 1953 UNITED STATES PATENT OFFICE CONTINUOUS CHROME MORDANTING AND DYEING F WOOL John N. Dalton, Providence, R. I., and John P. Ploubides, Lawrence, Mass., assignors to Pacific Mills, Lawrence, Mass, a corporation of Massachusetts Application November 23, 1949, Serial No. 129,146

2 Claims. (Cl. 8-99) "and scouring which characterizes the bottom chrome method, but at a cost which is much less than the cost of mordanting by the conventional bottom chrome methods.

It is well known that the old bottom chrome method, i. e., application of the mordant in a separate bath before the cloth is dyed gives a superior quality dyeing. This method. however, has the disadvantage of much higher cost as with other mordanting methods chrome and top chrome methods, with the result that the older bottom chrome method has almost entirely gone out of use. However, with these more recent methods, dyeings of inferior quality are often obtained due to a poor penetration and lack of solidity of color, which is caused by formation of a chrome-dye complex in the bath.

This invention has as an object to provide a process for mordanting wool piece goods which will be comparable, in the quality of the resulting dyeings, with the conventional bottom chrome method but yet will be less time-contrivalent chromium compound by passing the cloth from the padinto a hot acid bath to thoroughly soak the impregnated cloth with the acid solution, alternately and repeatedly exposing the cloth to steam and immersing it in the acid bath, then exposing the cloth, still wet with acid solution, for a substantial timeinterval to an atmosphere of steam and finally at least partially neutralizing the acid by running the cloth through a mild'alkaline bath or thoroughly washing it with water, all as the cloth is maintained continuously in motionv We have vfound that this treatment leaves the cloth in condition to be immediately dyed with a mor- 'dant acid dye. g V

One feature of our invention is the processing of the cloth as it is kept in continuous motion through the equipment by first padding it with a Wetting agent along with the unreduced mordant and thereafter thoroughly soaking it with acid before and after repeated exposure of the cloth to steam.

The accompanying drawing is a schematic illustration of representative apparatus in which our process can be carried out.

Referring to the drawing, the undyed cloth 2, in open width suitably prepared for mordanting and dyeing, is supplied to a conventional pad mangle which preferably is a three-bowl padder, the trough e of which is filled with an aqueous solution at F. to 212 F. containing a wetting agent and about 0.25% to 1.0% of its weight of sodium bichromate or other suitable mordanting agent. Several pieces of goods may be sewed together end-to-end to form a long length of cloth to be supplied to the padder. On entering the padder, the cloth is first immersed in the liquid bath by its passage about the roller 8, then is squeezed in the nip of rolls l0 and I2, again immersed in the liquid by its passage about a set of rollers I4 and finally led out of the bath over the guide roller l6 and through the nip of rolls l8 and I0, where its final liquid content is determined by the setting of the rolls.

From the pad mangle the cloth passes without interruption of its movement into a steam "box 251 where the operation of reducing the chromium compound to a trivalent chromium compound is carried out by soaking the cloth with ahot acid liquid and alternately immersing it in this liquid and steaming it, followed by substantial exposure to steam. The lower part of the steam box 26 is divided into three approximately equal sized, open- topped compartments 22, 24 and 26 by lowpartitions 2B and 3B. The cloth is led through the steam box 25 over a series of upper guide rolls 32 and a series of lower guide rolls 34 as shown.

Compartment 22 is filled with an acid solution maintained at a temperature in the range F. to 212 F. by steam which enters the compartment at any suitable point below the liquid level therein, as from steam supply pipe 2|.

On entering the steam box 26 the cloth is immediately led downwardly about guide roll 36 to immerse it in the acid solution in compartment 22, with which solution the Web of cloth is 'immediately soaked in its passage about guide roll 3 36 and the first of the series of lower guide rolls 34.

The cloth then passes alternately over an upper guide roll 32 and under a lower guide roll 34 so that it is alternately and repeatedly immersed in the acid liquid in compartment 22 and exposed to the steam atmosphere in the upper part of the steam box provided by steam from steam supply pipe 2!.

The cloth next passes in the same manner through compartment 24, which contains steam at atmospheric pressure but no liquid, so that the cloth is exposed to a steam atmosphere for a substantial period of time.

Next the cloth passes through compartment 26 which contains water which operates as a liquid seal and finally, the cloth emerges from steam box at 38 and is passed between the squeeze rolls 40.

The traveling cloth then passes over guide rolls 42 and through wash boxes Ml, 48 in which its acidity is reduced by washing with water. Desirably the water in the first wash box 44 may contain a mild alkali, such as diammonium phosphate, to accelerate the neutralization of the liquid content of the cloth.

The cloth on leaving the first wash box is passed through a pair of squeeze rolls 43 into the wash box 46, is given a final squeeze at 50 as it leaves box 06, and is then collected in any suitable manner at 52 as by passing it into a scray. The cloth then may be taken directly to the dye vat for dyeing.

The following examples of particular process conditions and particular dyestuffs are given as illustrative of the invention.

Example I One out of worsted gabardine yards in -length and 65" wide was continuously chrome mordanted by our process employing sodium bichromate and 0.5% of an alkylarylpolyether in the initial impregnating bath and 2% hydroxyacetic acid as the reducing solution. The material was allowed to remain within the chamber for 1 to 1 /2 minutes, and was then neutralized to a pH of 5.7 in a continuous open width washer with tap Water. The material was then dyed with the following color combination:

Color Index No., Pro- A comparable sample of the same gabardine material was mordanted by the conventional 'bottom chrome method, that is by boiling it in a kettle containing a bath of sodium bichromate and then dyed with the same color combination. The dyeing of the cloth mordanted by the process of Example I was of superior quality, having as good levelness and color solidity as the sample mordanted by the conventional bottom chrome method.

fulling and to scouring as compared with the sample mordanted by the conventional bottom chrome method. In the dyeing of the sample -mordanted by our process, 10% greater exhaus- In addition the sample mordanted by our process showed increased fastness both to tion was obtained than in the dyeing of the conventional sample.

Example II The procedure of Example I was repeated, with two identical samples of cloth, employing as the dyestufi:

Color Index No., or

Dye Vendor Amount Per Cent Eriochrome Blue Black R 0. Acid Alizarine Violet N. Anthraquinone Violet 3R Xvlene Milling Blue FF Metomega Chrome Grey GL. Wool Fast Blue Color Index No. 202. Color Index No. 169. Color Index No. 1080. Sandoz.

Do. Color Index No. 833.

' sults as to processing speed and quality of the dyeing are obtained by the use as a wetting agent of an alkylarylpolyether alcohol which may be present in the pad mangle in an amount of the order of about 0.5% by weight of the entire solution.

As the acid for reducing the chrome, we prefer hydroxyacetic acid because it contributes to the effectiveness and speed of our continuous process by virtue of its high reducing power in proportion to its acid value, permitting rapid passage of the cloth with rap-id reduction of the chrome without significant deleterious efiects on the wool substance due to acidity.

The pressure of the steam to which the cloth is exposed as it is alternatively immersed and steamed, and also during the final steaming treatment in compartment 24 is not a critical aspect of our process. Most conveniently, steam at atmospheric pressure can be employed and at this pressure is highly effective.

For best results the reducing bath should have a pH in the range 2-3.

The strength of the neutralizing alkali solution employed and the size and number of the wash boxes are so selected with respect to the other variable factors of our process, particularly the speed of travel of the cloth, that the cloth at completion is at a pH in the range 5.5 to 6.0.

We claim:

1. The method of mordanting wool cloth to prepare it for dyeing with a mordant dyestufi which consists essentially in continuously'immersing the undyed and unmordanted cloth in, and squeezing it to completely saturate it with, a hot aqueous solution consisting essentially of about 0.5% of the weight of the solution of an alkyl-arylpolyether alcohol and 0.25% to 1.0% of the weight of the solution of a water-soluble chromium compound selected from the class consisting of sodium bichromate and potassium bichromate, continuously reducing the chromium compound to a trivalent chromium compound by passing the wet impregnated cloth into a hot acid bath consisting essentially of between 0.5% and 6.0% of the weight of the bath of hydroxyacetic acid, thereafter continuously and repeatedly exposing the traveling cloth to steam at atmospheric pressure and immersing it in said acid bath, exposing the traveling cloth to thereafter dyeing the wool with a mordant dye stufi.

2. The method of mordanting wool cloth to prepare it for dyeing with 'a mordant dyestuff which consists essentially in continuously im-' mersing the undyed and unmordanted cloth in, and squeezing it to completely saturate it with, an aqueous solution at a temperature in the range 70 F. to 212 F. and consisting essentially of about 0.5% of the weight of the solution of an 'alkylarylpolyether alcohol and 0.25% to 1.0% of the weight of the solution of sodium bichro: mate, continuously reducing the sodium bichromate to a. trivalent chromium compound by pass; ing the wet impregnated cloth into a hot acid bath at a pH of about 2 to 3, said bath con} taining between 0.5% and 6.0% of the weight of the bath of hydroxyacetic acid, thereafter continuously and repeatedly exposing the traveling cloth to steam at atmospheric pressure and immersing it in said acid bath, exposing the traveling cloth to steam at atmospheric pressure, continuously passing the cloth through an alkaline neutralizing bath to raise its pH to about 5.5 to 6.0, and thereafter dyeing the wool with a mordant dyestufi.

JOHN N. DALTON. JOHN P. PLOUBIDES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 254,713 Simpson Mar. '7, 1882 1,492,051 Telen Apr. 29, 1924 1,970,578 Schoeller Aug. 21, 1934 2,106,634 Greiser Jan. 25, 1938 2,222,285 Ellner Nov. 19, 1940' FOREIGN PATENTS Number Country Date 8,874 Great Britain 1900 9,286 Great Britain 1886

Claims (1)

1. THE METHOD OF MORDANTING WOOL CLOTH TO PREPARE IT FOR DYEING WITH A MORDANT DYESTUFF WHICH CONSISTS ESSENTIALLY IN CONTINUOUSLY IMMERSING THE UNDYED AND UNMORDANTED CLOTH IN, AND SQUEEZING IT TO COMPLETELY SATURATE IT WITH, A HOT AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF ABOUT 0.5% OF THE WEIGHT OF THE SOLUTION OF ANALKYLARYLPOLYETHER ALCOHOL AND 0.25% TO 1.0% THE WEIGHT OF THE SOLUTION OF A WATER-SOLUBLE CHROMINUM COMPOUND SELECTED FROM THE CLASS CONSISTING OF SODIUM BICHROMATE AND POTASSIUM BICHROMATE, CONTINUOUSLY REDUCING THE CHROMIUM COMPOUND TO A TRIVALENT CHAROMIUM COMPOUND BY PASSING THE WET IMPREGNATED CLOTH INTO A HOT ACID BATH CONSISTING ESSENTIALLY OF BETWEEN 0.5% AND 6.0% OF THE WEIGHT OF THE BATH

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