US2515922A - Dyeing with 3, 4-thiolanedithione - Google Patents

Description

Patented July 18, 1950 UNITED STATES DYEIN G WITH 3,4-THIOLANEDITHIONE Philip D. Caesar, Champaign, 111., assignor to Socony-Vacuum i! Company, Incorporated, a

corporation of New York Application November 8, 1947, Serial No. 784,927

No Drawing.

Claims.

This invention relates to, a method of dyeing fabrics and, more particularly, is directed to a fabric dyed witha new sulfur-containing dye.

In. co-pendlng application Serial Number 721,453, filed January 10, 1947, h e is described a. new .orga-no-sulfur compound and a method for synthesizing the same. This compound is char-- acterized by the empirical formula CrHiSs and a boiling point. of 12 0-l 25 C. at a pressureof 2 millimeters of mercury. More recent investiga.- tions have shown this compound to be 3,4-thio lanedithione, having the following structure:

1 s=o o=s It has now been discovered that the above compound is an excellent dye, capable of imparting a characteristic color to articles treated therewith under the conditions hereinafter set forth.

In accordance with the present invention, it has been found that alkaline solutions of 3,4-thiolanedithione are colored deep purple and that materials immersed therein, exposed to an oxidizing atmosphere and dried, are dyed a fast, characteristic reddish-brown color.

The process of this invention is particularly applicable for dyeing fabrics of animal origin, such as wool and silk. It is, however, within the purview of the present invention to dye other fabrics, including those of cellulosic nature, such as cotton or linen. While the dye described herein will generally be employed for coloring tex tiles of the various types, it is also contemplated that 3,4-thiolanedithione can be used to color leather, leather substitutes, paper, cellophane, paints, inks, shoe polishes and other materials where color is considered to be a desirable 'attribute. As is well recognized, dyeing is a varied and complex art. The technique employed is dependent on the particular substance being 001- ored, and in treating each of the above mentioned materials, it is to be realized that the particular procedural steps involved in each instance will vary with the class of material being dyed.

In the case of wool and silk, which consist of proteinoid fibers, it has been found that direct immersion of the material into an alkaline solution of 3,4-thiolanedithione, removal of the material from said solution, and subjection of the treated material to an oxidizing atmosphere gives, after drying, a finished, fast-colored reddishbrown fabric. In the case of cotton, linen and other fibers of vegetable origin, it is a necessary prerequisite to immersion of the material in the 2 3,4.-thiolanedithione bath that it firstbe treated with a chemical fixingagent such as Turkey-red oil, tannic acid fixed on the fiber with tartar emetic, and others in order to. insure a final fast color.

Preparation of the dye bath is effected? in accordance with the provisions of the present invention by dissolving 3,4-thiolanedith-ione in hot alkali. The particular alkali employed: will generally be governed by economic factors and usually will be a hydroxide of an alkali or alkaline earth metal, suitably sodium, potassium or calcium hydroxide. The dissolution process can begreatly increased by the addition to the alkaline solution of a reducing agent such as zinc dust or sodium hydrosulfite. Accordingly, the dissolution bath is preferably one of alkaline-reducing agent;

The fabric to be dyed is immersed in the alkaline solution generally at a moderatel-y'elevated' temperature of between about 50 F. and-about 250 F. Higher temperatures, as a rule, are detrimental; After dyeing, the material must be-sufirciently oxidized tofully developthe color; To" bring about the desired oxidation, the fabric, after" removal from the alkaline bath, is subjected to an oxidizing atmosphere of air or'other oxygencontaining gas, or the oxidizing atmosphere may consist of a separate bath of a mild oxidant such as aqueous solutions of sodium bichromate or sodium perborate, into which th fabric, after treatment in the alkaline reducing bath of 3,4- thiolanedithione, is immediately conducted. The fabric, after treatment with an oxidant, is dried to give the final dyed product. If desired,

after the oxidation step but prior to drying, the

cloth may be treated with various improving agents such as formaldehyde and the like.

The process of this invention may be either carried out batchwise or in continuous fashion. In the latter operation, a sheet of the fabric tov be dyed is continuously immersed in an alkaline solution of the 3,4-thiolanedithione, removed therefrom, and passed through an oxidizing medium which may either be a separate bath of a mild oxidant or an oxygen-containing gas and, if necessary, thereafter continuously passed through a drying area and removed by winding on cylinders or other suitable means.

The following specific examples will further serve to illustrate the method of the present invention:

Example I Twenty parts by weight of 3,4-thiolanedithione were dissolved in parts by weight of an aqueone solution of 20 per cent sodium hydroxide maintained at a temperature of 212 F. over a period of about 6 hours to give a deep purple solution. A piece of wool fabric was immersed in this solution, removed therefrom and then immersed in a bath containing a mild oxidant consisting of an aqueous solution of per cent by weight ofsodium bichromate. The fabric, after removal from the oxidant bath, was dried and was found to have a fast, reddish-brown color which, when exposed to sunlight over a period of 2 weeks, still remained fast.

Example II Twenty parts by weight of 3,4-thiolanedithione were dissolved in an aqueous alkaline reducing solution containing parts by weight of sodium hydroxide and 20 parts by weight of sodium hydrosulfite maintained at a temperature of 212 F. for a period of two hours to give a deep purple solution. A piece of wool fabric was immersed in this solution, removed therefrom and then immersed in a bath containing a mild oxidant consisting of an aqueous solution of 5 per cent by weight of sodium bichromate. The fabric, after removal from the oxidant bath, was dried and was found to have a fast reddish-brown color which, when exposed to sunlight over a period of 2 weeks, still-remained fast.

Example III Twenty parts by weight of 3,4-thiolanedithione were dissolved in an aqueous alkaline reducing solution containing 20 parts by weight of sodium hydroxide and 50 parts by weight of zinc dust maintained at a temperature of 212 F. for a period of two hours to give a deep purple solution. A piece of wool fabric was immersed in this solution, removed therefrom and then immersed in a bath containing a mild oxidant consisting of an aqueous solution of 5 per cent by weight of sodium bichromate. The fabric, after removal from the oxidant bath, was dried and was foundto have a fast, reddish-brown color which, when exposed to sunlight over a period of 2 weeks, still remained fast.

From the above examples, it will be seen that 3,4-thiolanedithione is an excellent, fast dyestufi. It will be understood that the above embodiments are to be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

I claim:

1. A method for dyeing a fabric, comprising immersing the same in an alkaline solution of 3,4- thiolanedithione, removing the treated fabric from said solution and subjecting the fabric to an oxidizing atmosphere.

2. A method for dyeing a fabric, comprising immersing the same in an alkaline solution of 3,4- thiolanedithione, removing the treated fabric from said solution and subjecting the treated fabric to the oxidizing action of air.

3. A method for dyeing a fabric, comprising immersing the same in an alkaline solution of 3,4- thiolanedithione, removing the treated fabric from said solution and immediately thereafter immersing the fabric in an oxidant bath, removing the fabric from said bath and drying.

4. A method for dyeing a fabric consisting of proteinoid fibers, comprising immersing the same in an alkaline solution of 3,4-thiolanedithione,

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

UNITED STATES PATENTS Name Date Homolka July 21. 1908 Number

Claims (1)

1. A METHOD FOR DYEING A FABRIC, COMPRISING IMMERSING THE SAME IN AN ALKALINE SOLUTION OF 3,4THIOLANEDITHIONE, REMOVING THE TREATED FABRIC FROM SAID SOLUTION AND SUBJECTING THE FABRIC TO AN OXIDIZING ATMOSPHERE.