US3802835A

US3802835A - Alcohol-ammonia dye solution and dyeing therewith

Info

Publication number: US3802835A
Application number: US00277771A
Authority: US
Inventors: H Prieto
Original assignee: North American Mills Inc
Current assignee: North American Mills Inc
Priority date: 1972-08-03
Filing date: 1972-08-03
Publication date: 1974-04-09
Anticipated expiration: 1991-04-09

Abstract

A dye system in which materials are bathed in a dyebath formed of a dye dissolved in a substantially anhydrous liquid ammonia. A mono-hydroxy lower alkyl alcohol is added as a leveling agent and to improve hand.

Description

United States Patent Prieto Apr. 9, 1974 ALCOHOL-AMMONIA DYE SOLUTION [56] References Cited AND DYEING THEREWITH UNITED STATES PATENTS [75] Inventor: Humberto Prieto, Gastonia, NC. 3,666,398 5/1972 Tramyek 8/82 [73] Asstgnee: 2232522 3 2 Mills? Primary Examiner-Donald Levy Attorney, Agent, or FirmSchiller & Pandiscio [22] Filed: Aug. 3, 19 72 I 211 App]. No.2 277,771 [571 ABSTRACT A dye system in which materials are bathed in a dyebath formed of a dye dissolved in a substantially anhy- [52] U5. Cl 88//l8 A,88/g337,88//l4743, drous liquid ammonia A mono hydroxy lower alkyl [51] Int Cl DMD D06p U38 alcohol is added as a leveling agent and to improve I hand Field of Search .Q 8/82 173, 37, 44, l A

18 Claims, No Drawings ALCOHOL-AMMONIA DYE SOLUTION AND DYEING THEREWITH This invention relates to systems of dyeing or coloring materials and more particularly to new methods of dyeing materials such as proteinaceous, cellulosic and synthetic fibers and sheets.

Dyes are usually applied to fibrous material from aqueous solution, and generally require imbibition periods of many minutes even with heated solutions. Ad-

ditionally, various dyes capable of dyeing one type of fiber in aqueous solution are ineffective for other types of fiber. A usual classification of dyestuffs is according to their use, and typically will include direct, disperse, naphthol, reactive and sulfur dyes.

' Direct dyes are water-soluble dyes that exhaust onto cellulosic fibers from a salt bath without mordanting. Chemically nearly all direct dyes are azo products with one or more sulfonic radicals, and most contain a plurality of the azo groups. They are used on cotton, rayon, silk and wool but are not ordinarily considered suitable for dyeing cellulose acetate.

Disperse dyes are colored organic dyes that although relatively insoluble can be dispersed in water in particulate form. These dyes typically are not useful on cotton or viscose rayon, but the particles have an affinity for and thus dye cellulose acetate well.

Naphthol dyes are water-insoluble azo dyes usually formed on or in a fiber by a two-step process in which a diazotized organic amine is combined in aqueous solution with naphthol previously impregnated into the textile material. These are primarily used to dye cotton, rayon, silk and nylon.

Dyes with chemically reactive groups which can react with a substrate material to bind themselves chemically to the substrate are known as reactive dyes. Usually, special conditions or operations are required to use such dyes.

Sulfur dyes are normally insoluble substances brought into water-soluble form for dyeing by treatment with hot alkali solution containing Na s. These are generally used for coloring cotton and, to a limited extent, on silk and rayon because the hand of the latter is adversely affected. Because of severe damage from the alkaline sulfur bath, these dyes are not used on wool.

The usual dyeing systems and the types of fibers for which a dye is particularly useful have heretofore been largely limited to dyeing from aqueous solution. While dyeing from aqueous solution systems may provide reaorganic solvents currently used may be undesirable from a standpoint of safety, and produce poisonou sonably satisfactory dyeings from a standpoint of color tone and dye levelness, such systems have the disadvantage in usually requiring relatively long imbibition times, e.g., typically from about 30 minutes-l0 hours or more. As a result, the dye vats, etc., must be relatively large thus increasing capital investment. Furthermore, such systems normally require relatively high dyebath temperatures which may often approach the boiling point of water. Such increases utility costs of operating the system. An additional disadvantage of aqueous systems is pollution from disposal of spent dyeing solutions.

in a few limited instances, dyes had been applied from organic solvents systems such as alcohols or aromatics and the like. However, such systems may require solvent recovery both from an economic standpoint and to avoid pollution. Furthermore, some of the gases or may be flammable.

One current system of dyeing involves dyeing from liquid ammonia solution according to the method disclosed by Tratnyek, U.S. Pat. No. 3,666,398. With this method imbibition time is radically less as compared to dyeing from aqueous systems. Also, in this method dyeing is accomplished at low temperatures, and does not involve the use of costly solvent. On the other hand, in

the Tratnyek method dyeings may occasionally be unlevel and coarsen the fiber. The unlevelness is believed to be attributed at least in part to the very high speed at which dyeing occurs in the liquid ammonia dyebath. In any event, whatever the cause of the unlevelness, it poses a problem in the commercial exploitation of the Tratnyek method except in cases where dye levelness is not required.

It is thus a primary object of the present invention to provide a novel dyebath for dyeing substrate materials. Another object of the invention is to provide a novel method of leveling dyeings with dyestuffs applied from liquid ammonia solution. A more specific object is to provide a novel method of improving the levelness of dyeings made according to the Tratnyek U.S. Pat. No. 3,666,389 and to improve the hand of fabric so dyed.

To effect the foregoing and other objects, the present invention generally contemplates the use of a monohydroxy lower alkyl alcohol in a dye system comprising a dyestuff dissolved in substantially anhydrous liquid ammonia.

Other objects of the invention will in part be obvious and will in part appear hereinafter. The invention accordingly comprises the processes involving the several steps and the relation of one or more of such steps with respect to each of the others, and the products possessing the features, properties and relation of elements which are all exemplified in the following detailed disclosure and the scope of the application of which will be indicated in the claims.

In the following detailed description of the present invention, the term liquid ammonia refers to aminonia (NI-l in itsliquid state, i.e., which boils at about -33,.4C. at 760 Hg. pressure, and not to a solution of ammonium hydroxide. However, it will be appreciated that water can be mixed with liquid ammonia in surprisingly large amounts without the water becoming frozen. Even when approximately equal quantities of liquid ammonia and water are mixed, there remains an appreciable quantity of the liquid ammonia in the mixture so long as the mixture is maintained at equilibrium conditions below the boiling point of the liquid ammoma.

As used herein the term mono-hydroxy lower alkyl alcohol refers to aliphatic alcohols having from one to three carbon atoms, i.e., methanol, ethanol, and the propanols (n-propanol and iso-propanol).

Generally, a mixture of liquid ammonia and the mono-hydroxy lower alkyl alcohol isprepared by adding the alcohol to liquid ammonia, preferably in the proportion of from about 17 to percent by volume of alcohol to ammonia. The alcohol preferably is chilled prior to addition of the liquid ammonia mixing so as to minimize loss of liquid ammonia by vaporization.

Thereafter, a dyestuff is dissolved in the liquid ammonia-alcohol mixture to form a dyebath. Alternatively, at least a part of the dyestuff may be dissolved in the liquid ammonia prior to admixture with the alcohol, and the remainder of the dyestuff, if any, is subsequently dissolved in the liquid ammonia-alcohol mixture. Another procedure is to dissolveat least a part of the dyestuff in the alcohol, and admixing with the liquid ammonia, and the remainder of the dyestuff, if any, is subsequently dissolved in the liquid ammonia. The latter procedure can obviously only be used with dyestuffs which are soluble in the selected alcohol.

The usable dyes include those dyes which are soluble in liquid ammonia, such as direct, disperse, napthol, reactive, and sulfur types. Vat'dyes do not appear to be soluble in liquid ammonia, hence, are considered among the substances not included in the invention. The dyebaths of the present invention are effective for dyeing a wide range of materials to which they are applied, for example, cotton, silk, wool, viscose, rayon, acetate, triacetate, acrylic, modacrylic, nylon, polyester, and other natural and synthetic materials. As is now known, certain materials that are not considered dyeable by a particular dye in aqueous or organic solvents, unexpectedly proved to be quite dyeable by that dye in a liquid ammonia dye bath and are equally dyeable in a liquid ammonia-mono-hydroxy lower alkyl alcohol dyebath. For example, direct dyes and reactive dyes, in liquid ammonia, with or without alcohol color triacetate deeply'. Further, in both liquid and ammonia and liquid ammonia-alcohol dye baths, dyeing is generally completed in about 20 seconds or less, although application of the same dye with conventional aqueous systems employs much longer imbibition times and much higher dyebath temperatures.

The depth of shade achieved in the present invention as in the use of liquid ammonia dye baths appears to de pend primarily on the concentration of the dyestuff in the liquid ammonia-mono-hydroxy lower alkyl alcohol solution, and not on dwell time of the fibers in the dyebath. Imbibition periods greater than about 20 seconds do not normally materially improve coloration.

That the addition of the mono-hydroxy lower alkyl alcohol to the dyestuff-liquid ammonia systems of Tratnyek is responsible for the unique consequences achieved is quite clear inasmuch as dyebaths prepared from the same dye dissolved in'substantially anhydrous liquid ammonia by itself, or the alcohol by itself (i.e., with dyestuffs which are soluble in the alcohol), failed to provide comparable results.

The following examples, illustrative of the principles of the present invention, are based upon application of a bath of a dyestuff dissolved in substantially anhydrous liquid ammonia containing a mono-hydroxy lower alkyl alcohol, to a number of different materials as follows: (1) bleached 80 X 80 cotton print cloth; (2) bleached mercerized 80 X 80 cotton print cloth; (3) spun viscose rayon print cloth (high wet modulus); (4) spun triacetate cloth and (5) a multifiber test fabric consisting of cloth bands of the following sequence of fibers identified generically, and in some instances by trade name: dull acetate; acrylic (Acrilan 1956); triacetate (Arnel dull); raw cotton; acrylic (Creslan 61), polyester (Dacron 54); polyester (Dacron 64); nylon (nylon 60); acrylic (Orlon 75); silk; modacrylic (Verel A); viscose; and wool. r

Generally in the following examples, in order to compare the leveling effect of adding a mono-hydroxy lower alkyl alcohol to a liquid ammonia bath, each dye was applied to fabric by two different methods: from a liquid ammonia bath, and from a liquid ammonia bath containing a mono-hydroxy lower alkyl alcohol. Both the liquid ammonia and the liquid ammonia-monohydroxy lower alkyl alcohol solution were substantially anhydrous. Dye concentrations in the solutions were as indicated with a total fabric-to-liquor ratio of about 20 to l in all cases.

The basic procedure was to submerge all swatches of fabric in the dye solution for 20 seconds for ammonia or ammonia-alcohol dyeings. Excess ammonia and alcohol was allowed to evaporate from the treated fabrics at room temperature (about 20C) before drying in an oven at 120130C for about 1 to 2 minutes. The dyed fabrics were then usually rinsed or washed in warm water. Rinsing the fabrics was continued until excess dye was removed from the fabrics or until rinse water showed little or no coloring. The fabrics were then dried by ironing.

EXAMPLE I Dye: Sirius Red F3B (Bayer) (C.I. N. 35780) (C.l. Direct Red v) 7 The Colour Index describes thisdye as an polyazo type used for dyeing cotton, silk and'wool. It may also be used for direct printing on these fibers.

Anhydrous ammonia application Prepare the dyebath by dissolving 2 gms. of dye in ml. anhydrous ammonia.

Saturate the fabrics (1 1.0 gms. total) in the dyebath for 20 seconds. Remove fabrics from dyebath and allow excess ammonia to evaporate at 20C. Finish drying at l35C for about 2 minutes. Rinse in. warm water and iron dry as above.

Anhydrous ammonia alcohol application 10 percent solution of isopropanol in ammonia is prepared by slowly adding liquid anhydrous ammonia (42C) to 100 ml. anhydrous isopropanol (0C) to make 1,000 ml. solution. The resulting solution is observed to be colorless. No separation of alcohol and ammonia is observed. Temperature of solution---37C.

Prepare dyebathby dissolving 2 gms. of dye in 100 ml. of the ammonia-alcohol mixture.

Saturate the fabrics (12.1 gms. total) in the dyebath for about 20 seconds. Remove fabrics from dyebath and dry the fabrics at 20C to remove excess ammonia and alcohol before final drying at C. for about 2 minutes. Rinse as before and iron dry.

Application of dyestuff from anhydrous ammonia and from ammonia-alcohol mixture produce intense coloration of dull acetate, triacetate, viscose and silk. Cottons are dyed in a lighter shade. The dyeing of cottons and rayons with this technique does not produce as deep a coloration as that obtained in conventional dyeing. However, triacetate which is uncolored by the conventional technique, can be highly colored using the anhydrous ammonia dyebath. Unleveled dyeing is observed on many of the'fabrics dyed from ammonia only. Dye levelness is particularly poor on the cottons and rayons.

Dye levelness on dyeings from the ammonia-alcohol mixture is comparable to dyeings made by the conventional aqueous techniques.

EXAMPLE u The purpose of this example is to see if dyeing levelness varies with the ratio of alcohol-to-ammonia.

Following the procedure described in Example 1, mixtures are prepared of the following amounts of isopropanol in substantially anhydrous liquid ammonia (all percentages by volume percent):

A. 1 percent isopropanol in liquid ammonia;

B. 2 percent isopropanol in liquid ammonia;

C. 5 percent isopropanol in liquid ammonia;

D. 30 percent isopropanol in liquid ammonia;

E. 50 percent isopropanol in liquid ammonia.

Swatches of fabric dyed from ammonia, and from the ammonia-alcohol mixture are compared for hand. The fabrics dyed from the ammonia-alcohol mixture will be found to have improved hand over the fabrics dyed from ammonia only.

In each case the alcohol and the liquid ammonia appear to be completely miscible with each other and no separation is observed.

Prepare dyebaths by dissolving gram portions of Direct Red 80 dye in solutions A E.

Saturate samples of the fabrics in the dyebaths for about 20 seconds. Remove the fabrics from the dyebath and dry the fabrics at 20C to remove excess solvent before final drying at 135C for about 2 minutes. Rinse and wash with detergent as before. Iron dry.

Results By comparing swatches with those obtained in Example I, one sees that the presence of various amounts of isopropanol in the liquid ammonia solvent appears to improve dyeing levelness and hand as compared with dyeings made by application from liquid ammonia only. Increasing the amount of isopropanol up to about percent by volume does appear to increase levelness. Beyond 10 percent by volume little difference is seen in dyeing levelness.

EXAMPLE III The purpose of this Example is to see if other alcohols will improve dyeing levelness and hand of dyeings from liquid ammonia.

Following the procedure described in Example 1, mixtures are prepared with 10 percent volume amounts of the following alcohols in substantially anhydrous liquid ammonia:

A. 10 percent methanol in liquid ammonia;

B. 10 percent ethanol in liquid ammonia;

C. 10 percent n-propanol in liquid ammonia;

D. 10 percent rn-butanol in liquid ammonia;

E. 10 percent sec-butanol in liquid ammonia;

F. 10 percent tert-butanol in liquid ammonia;

G. 10 percent benzyl alcohol in liquid ammonia.

In the case of methanol, ethanol, and'n-propanol, the alcohol and the liquid ammonia appeared to be completely miscible with each other and no separation was observed. There is a slight amount of sizzling observed when the liquid ammonia is added to the methanol and to the ethanol.

In the case of the butanols, a slight degree of separation can be noted in some instances. With-benzyl alcohol, two discrete layers are observed,'indicating little or no solubility of benzyl alcohol and liquid ammonia in each other.

Prepare dyebaths by dissolving 2 gramportion-of Direct Red 80 dye in 100 ml each of mixtures A G. Dye appears to be fully dissolved homogeneously throughout mixtures A F. Dye appears to dissolve only in the larger layer, i.e., in the liquid ammonia of mixture G.

Saturate samples of the fabrics in the dyebaths for about seconds. Remove sample of the fabrics from the dyebaths and ammonia and alcohol before final drying at 135C for about 2 minutes. Rinse and wash with detergent as before. Iron dry.

Results By comparing swatches with those obtained in Example I, one sees that dyeings made with solutions A C have substantially improved levelness over the dyeing applications from liquid ammonia only. Dyeings made with solution mixtures D F have slightly improved levelness comparable to dyeing applications from liquid ammonia only, and dyeings from mixture G is substantially as unlevel as dyeings from liquid ammonia'only. Hand improves with dyeings from mixtures A C as compared with dyeings from liquid ammonia only.

EXAMPLE IV The purpose of this example is to see if addition of a glycol will improve hand and levelness of dyeings from anhydrous liquid ammonia.

Following the procedures described in Example I, mixtures are prepared with the following amounts of ethylene glycol in anhydrous liquid ammonia (all percentages by volume percent):

A '1 percent ethylene glycol in liquid ammonia;

B. 2 percent ethylene glycol in liquid ammonia;

C. 3 percent ethylene glycol in liquid ammonia;

D. 10 percent ethylene glycol in liquid ammonia.

I In each case the ethylene glycol and the liquid ammonia appear to be completely miscible with each other and no separation into layers is observed.

Prepare dyebaths by dissolving 2 grams of Direct Red dye in ml. portions of each of solutions A D.

Saturate samples of the fabrics in the dyebaths for about 20 seconds. Remove the samples from the dyebaths and dry the fabrics at 20C to remove excess solvent before fmal drying at C for about 2 minutes. Rinse and wash with detergent as before. Iron dry.

Results By comparing swatches with those obtained in Example I, one sees that the dyeings made with solutions containing ethylene glycol have about the same hand and unlevelness as dyeings made from liquid ammonia only.

EXAMPLE v percent solution of ethanol in ammonia is prepared by' slowly adding liquid anhydrous ammonia (42C) to 100 ml. anhydrous ethanol (0C) to make 1,000 m1. solution. The resulting solution is observed to be colorless. No separation of alcohol and ammonia is observed. Temperature of solution 40C.

saturated in the dyebath for seconds and then drained and air dried at 20C to remove excess ammonia. Final drying is at 135 140C for several minutes. Finally, the fabrics are washed and ironed dry as before.

From an anhydrous ammonia dyebath and from anhydrous ammonia-methanol mixture, Disperse Blue 7 dyes acetate, triacetate, and silk in dark shades. Medium shades are obtained for nylon and viscose; dacrons, cottons, and rayons are not lightly colored. Unleveled dy'eings are observed on many of thefabrics dyed from liquid ammonia solution. Dyeings from the ammonia-alcohol mixture is observed to be substantially level and has improved hand as compared to dyeings from liquid ammonia only.

EXAMPLE Vl Dye: Napthol AS Supra (C.l. Azoic Coupling Component 2) (General Aniline and Film Corp.) Fast Scarlet Salt GGN (C.I. Azoic Diazo Component 3) (General Aniline and Film Corp.) Naphthol dyeing requires ,two' components, the naphthol dye and the developer, to obtain coloring. v

The Color Index describes the Azoic Coupling Component 2 (CI. No. 27505) as 3-hydroxy-2- naphthanilide. It is sparingly soluble in alcohol and insoluble in water. The Azoic Diazo Component 3 bears the Colour index No. 37010. i

1 Anhydrous ammonia application Dyeing from a completely anhydrous ammonia system could not be done because the developer was insoluble in the ammonia. However, dyeing was achieved in a two-step process in which the naphthol is dissolved in anhydrous ammonia and the developer in an aqueous solution.

Naphthol AS (.2 grns.) was dissolved in anhydrous ammonia (280 ml.). The fabrics l4.0 gms. total) were saturated in solution and then allowed .to dry at room temperature. Then the fabrics were. treated in the developer solution and finished as previously described.

. AnhydrousAmmonia Alcohol Application 10 percent solution of isopropanol in ammonia is prepared following the procedure of Example 1. Dyeing is then achieved in a two-step process in which the napthol is dissolved in anhydrous ammonia-alcohol mixture, and the developer in an aqueous solution.

Naphthol AS (4.4 gms.) is dissolved in anhydrous ammonia-alcohol mixture (300 ml.). The fabrics 14.7 gms. total) are saturated in solution and then allowed to dry at room temperature. Then the fabrics are treatedin the developer solution and finished as earlier described. I

Using anhydrous ammonia as the solvent for one dye component and water for the other,'intense dyeings of cotton and silk are obtained and particularly brilliant dyeing of myrrh. Triacetate is not dyed by this technique. Unleveled dyeings can be observed however on many of the fabrics dyed from liquid ammonia solution. Dyeings from ammonia-alcohol mixture will be somewhat less deep in shade but substantially level. Hand is to be improved from dyeings with ammonia-alcohol mixture as compared with dyeings from ammonia only,

particularly for silk and rayon.

EXAMPLE vn Dye: Procion Brilliant Blue MRS (lCl) (C.l. Reactive Blue 4) This dye is identified in the Reactive Dye Chart in I Textile World, August 1964 as having the following structure:

Anhydrous Ammonia Application Prepare dyebath with 3.6 gms. of dye in 240 ml. of anhydrous ammonia. Saturate the fabrics l2.l gms. total) in the dyebath for 20 seconds. Remove fabrics from dyebath, dry off the excess ammonia at 20C before final drying at C for about 1 minute. Rinse, and iron as before.

Anhydrous ammonia-alcohol mixture application 10 percent solution of isopropanolin ammonia is prepared following the procedure of Example 1. Prepare dyebath from dye and ammonia-alcohol mixture. Saturate the fabrics (12.4 gms. total) in the dyebath for 20 seconds. Remove fabrics from dyebath, dry off the excess ammonia and alcohol at 20C before final drying at 120C for about one minute. Rinse and iron as before.

Results With both anhydrous ammonia and with anhydrous ammonia-alcohol solution, deep dyeing of acetate, triacetate, and silk is obtained. Cottons and rayons are lightly dyed.

Levelness of dyeings made from the ammoniaalcohol mixture will appear superior'to levelness of dyeing from ammonia only. Hand improves by dyeing from ammonia-alcohol mixture as contrasted with ammonia only.

EXAMPLE Vlll Dye: Dykolite Brilliant Orange 36 (Southern Dyestuff Company) (Sulfur Dye) No Color Index information is available for this dyestuff. The manufacturer describes it as a thiocondensate dye for cellulosic fibers. It is prereduced and is supplied as a powder soluble in water.

Dykolite Brilliant Orange 30 has the following structure according to the article Dykolite Dyestuffs for Cellulosic Fibers, Weston and Griffith, Textile Chemist and Colorists, 1, No. 22, pp. 67-82, in one isomeric form:

Anhydrous ammonia application One-step: To simplify the dyeing process, the dyestuff and fixative are placed in the same bath.

The dyebath is prepared by dissolving 4.7 gms. of dye and 1.2 gms. of Dykoset F-4O (the insolubilizing agent for the dye) in about 315 ml. of anhydrous ammonia to make a 1.5 percent solution of dye. All fabrics (15.6 gms. total) are saturated for about 20 seconds in the dyebath. Air dry the ammonia from the fabrics at 20C. Briefly wash the fabrics in warm water and iron dry.

Anhydrous ammonia application Two step: In

' order to see if better coloring of fabric could be obtained from two step processing, dye is placed in one bath of anhydrous ammonia, and insolubilizer in another, and the fabrics are treated sequentially in each.

The dyebath is prepared by dissolving 3.8 gms. of the dye in 248 ml. of anhydrous ammonia (1.5 percent solution of dye), and the insolubilizing bath by dissolving 1.0 gm. of Dykoset F-40 in 248 ml. of anhydrous ammonia. A total of 12.4 gms. of fabric is first saturated in the dyebath for seconds. The excess ammmonia is allowed to evaporate in air and then the fabrics are saturated for a few seconds in the insolubilizing bath. Excess ammonia is evaporated in air at about 20C, followed by a quick oven dry at l35-l40C. The fabrics are rinsed and washed as before and then ironed dry.

Anhydrous ammonia-alcohol application Prepare 10 percent mixture of isopropanol is ammonia as before. Prepare dyebath with 3.6 gms. of dye in 250 ml. of ammonia-alcohol solution. The dye does not appear completely soluble. Saturate the fabrics (12.2 gms. total) in the dyebath for 20 seconds. Dry off the excess ammonia-alcohol at 20C before final drying at 120C for about 1 minute. Wash and iron as before.

Results Application of dyestuff from anhydrous ammonia and from anhydrous ammonia-alcohol mixture, either as a one step or two step process, produces similar results whereby intense color is imparted to acetate, triacetateand silk. Cottons and rayons are lightly colored. Color will not be removed in dry cleaning.

Dyeings with anhydrous ammonia will be somewhat unleveled, particularly dyeings of the acetates and silk and the fiber felt coarse. Dyeing from the ammoniaalcohol mixture will be observed to be substantially level and provide better hand.

EXAMPLE IX The purpose of this example is to show how depth of shade varies with concentration of dye in anhydrous ammonia-alcohol mixture as it does from an ordinary ammonia dyebath. Direct Blue 67 (Pyrazol Fast Brilliant Blue A) is used as the dye for this study. The following dyebaths are prepared (percent in vol. percent).

1 gm. dye in 300 ml. 10 percent isopropanol in liquid ammonia 2 gms. dye in 300 ml. 10 percent isopropanol in liquid ammonia 4 gms. dye in 300 ml. 10 percent isopropanol in liquid ammonia Each fabric to be dyed is saturated for 20 seconds in I the dyebath. The fabrics are dried in air at 20C to remove excess ammonia and isopropanol, and finally EXAMPLE X The purpose of this example is to show how depth of shade varies with length of time in the dyebath. Direct Blue 67 (Pyrazole Fast Brilliant Blue A) again is selected as the dye for this study. For each time interval, a'dyebath is prepared with 1 gram of dye in 300 ml. of 10 percent isopropanol in anhydrous ammonia. Fabric is saturated in the dyebaths for the following times: 2 seconds, 20 seconds, 1 minute and 5 minutes. Excess ammonia and alcohol are evaporated from fabrics at 20C before oven drying for 2 minutes at C. The fabrics are then washed in hot waterand ironed dry.

Results After 20 seconds, depth of shade does not appear to increase with increased time in the dyebath. Fabric treated for only 1 second appears lighter in shade than fabric treated 20 seconds. Therefore, dye pickup on the fiber seems to occur between 1 and 20 seconds as it does in dyeing from an alcohol free ammonia dye bath.

As'appears clearly from the foregoing, dyeing from a liquid ammonia dyebath which contains an aliphatic lower alcohol offers all of the advantagesof a novel rapid method of dyeing at low temperatures achieved by the Tratnyek process with the further advantages improved levelness and hand.

Since certain changes may be made in the above systems without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description shall be interpreted in an illustrative and not in a limiting sense.

What is claimed is:

1. A dyebath comprising in combination: a

a body of liquid ammonia having a monohydroxy lower alkyl alcohol dissolved therein, and

a dyestuff soluble in liquid ammonia, dissolved in said body.

2. A dyebath asdefined in claim 1 wherein said alcohol is selected from the group consisting of methanol, ethanol, n-propanol and isopropanol.

3. A dyebath as defined in claim 1 wherein said dye stuff is selected from the group consisting of direct, disperse, naphthol, reactive and sulfur dyes.

4. A dyebath as defined in claim 1 wherein said alcohol is isopropanol.

5. A dyebath as defined in claim 1 wherein said alcoho] is n-propanol.

6. A dyebath as defined in claim 1 wherein said alcohol is ethanol.

7. A dyestuff as defined in claim 1 wherein said alcohol is methanol.

8. In a method of dyeing organic materials by applying to said materials a dyebath of liquid ammonia having a dyestuff dissolved therein, the improvement comprising adding a mono-hydroxy lower alkyl alcohol to said dyebath.

9. In a method as defined in claim 8 wherein said mono-hydroxy lower alkyl alcohol is selected from the stuff is selected from the group consisting of direct, disperse, naphthol, reactive and sulfur dyes.

14. Method as defined in claim 11 wherein said dyestuff is direct dye.

15. Method as defined in claim 11 wherein said dyestuff is a disperse dye.

16. Method as defined in claim 11 wherein said dyestuff is a naphthol dye.

17. Method as defined in claim 11 wherein said dyestuff is a reactive dye.

18. Method as defined in claim 11 wherein said dyestuff is a sulfur dye.

Claims

2. A dyebath as defined in claim 1 wherein said alcohol is selected from the group consisting of methanol, ethanol, n-propanol and isopropanol.
3. A dyebath as defined in claim 1 wherein said dyestuff is selected from the group consisting of direct, disperse, naphthol, reactive and sulfur dyes.
4. A dyebath as defined in claim 1 wherein said alcohol is isopropanol.
5. A dyebath as defined in claim 1 wherein said alcohol is n-propanol.
6. A dyebath as defined in claim 1 wherein said alcohol is ethanol.
7. A dyestuff as defined in claim 1 wherein said alcohol is methanol.
8. In a method of dyeing organic materials by applying to said materials a dyebath of liquid ammonia having a dyestuff dissolved therein, the improvement comprising adding a mono-hydroxy lower alkyl alcohol to said dyebath.
9. In a method as defined in claim 8 wherein said mono-hydroxy lower alkyl alcohol is selected from the group consisting of methanol, ethanol, n-propanol and isopropanol.
10. In a method as defined in claim 8 wherein said mono-hydroxy lower alkyl alcohol is isopropanol.
11. A method of dyeing organic materials from a dyebath comprising the steps of dissolving a dyestuff in a solvent of liquid ammonia to form said dyebath and adding thereto a mono-hydroxy lower alkyl alcohol.
12. Method as defined in claim 11 wherein said mono-hydroxy lower alkyl alcohol is admixed with said ammonia prior to dissolving said dyestuff in said ammonia.
13. Method as defined in claim 11 wherein said dyestuff is selected from the group consisting of direct, disperse, naphthol, reactive and sulfur dyes.
14. Method as defined in claim 11 wherein said dyestuff is direct dye.
15. Method as defined in claim 11 wherein said dyestuff is a disperse dye.
16. Method as defined in claim 11 wherein said dyestuff is a naphthol dye.
17. Method as defined in claim 11 wherein said dyestuff is a reactive dye.
18. Method as defined in claim 11 wherein said dyestuff is a sulfur dye.