US2520080A

US2520080A - Dyeing basic nitrogenous fibers by the metachrome process with chromable azo dyes having nitrogen free substituents ortho to the azo group

Info

Publication number: US2520080A
Application number: US761983A
Authority: US
Inventors: Chester A Amick; Willard H Watkins; Henry E Millson
Original assignee: American Cyanamid Co
Current assignee: Wyeth Holdings LLC
Priority date: 1947-07-18
Filing date: 1947-07-18
Publication date: 1950-08-22
Anticipated expiration: 1967-08-22

Description

Aug. 22, 1950 c. A. AMICK ETAL 2,520,080 DYEING BASIC NITROGENOUS FIBERS BY THE METACHROME PROCESS WITH CHROMABLE AZO DYES HAVING NITROGEN FREE SUBSTITUENTS ORIHO TO THE AZO GROUP 4 Sheets-Sheet 2.

Filed July 18, 1947 CONTROL By HEN/F) LSD/V,

ATTORNEY Aug. 22, 1950 Filed July 18, 1947 c. A. AMICK ETAL 2,520,080 DYEING BASIC NITROGENOUS FIBERS BY THE METACHROME PROCESS WITH CHROMABLE AZO DYES HAVING NITROGEN FREE SUBSTITUENTS ORTHO TO THE AZO GROUP 4 Sheets-Sheet 5 CONT/POL.

r ATTORNEY Aug. 22, 1950 c. A. AMICK ETAL 2,520,030

DYEING BASIC NITROGENOUS FIBERS BY THE METACHROME PROCESS WITH CHROMABLE AZO DYES HAVING NITROGEN FREE SUBSTITUENTS ORTHO TO THE AZO GROUP Filed July 18, 1947 4 Sheets-Sheet 4 GOA 714 04 .20

Patented Aug. 22, 1950 DYEING BASIC NITROGENOUS FIBERS BY. THE METACHROME. PROCESS WITH 'CHR'OMABL'E A'ZO DYES HAVING. N ITRJO- GEN' SUBSTETUENTS ORTHO TO THE AZO GROUP Chester A. Amick and WillardIH..Watkins-,.Bound Brook, andHenry- E. Millson, Plainfield, NHL. assignors to- American *Cyanamid Company, New York, N. 1 a corporation-of Maine Application July 18, 1947, Serial No. 761,983

15 Claims.

This invention relates to improvements in the metachrome dyeing processwith chromable azo dyes having nitrogen freev metallizable groups ortho tovtlie. azozgroupz In: the past, fibers such: as Wool, silk, synthetic fibers of. similar: type. from: casein, polyamides and thelikehaveabeen dyedby the metachrome process in which the dyestuif and a mordant containing a chromium compound have been present in the dyebath. In the dyeing procedure the dye is. affixed to-thefiber and is metallized. There have" been many. disadvantages to the metachrome dyeing process. For example, dye penetration has sometimes been: inadequate because of. premature reaction withthe chromium in the mordant; Thus dyes which donotpenetrate all of the fibers or are destroyed during thedyeing operation, particularly in the case of heavy shades, have been considered unsuitable for use in the metachrome process and have required resort to a process starting out with the preformed metallized dye or with a top or bottom chome process. Azo dyestuffs having only hydroxyl groups ortho to the azo group have not given as good results in the metachrome process and'have been considered'less suitable for dyeing by that process.

Numerous attempts have been made to increase the penetration ofthe dyes and obtain stronger dyeings. One of the earlier attempts involved the use of cationic surface active agents; This process, however, did not achieve practical success because although greatly increased penetration sometimes resulted there was reaction between the surface active agent and the colored constituents of thedye' bath to produce a colored precipitate; scum orflocs. These-larger colored aggregates" oftencaused serious spots or-flocs in the" dyeing and precluded practical use of this method. The next development which was practica'llyuseful involved'the addition to-the metachrome dyebat-h' of both cationic and nonionic surface activeagents, the latter serving to keep the reaction products of the cationic agent and colored constituents in fined dispersion. This process forms the-subject matter of the application of Millson and Royer, Serial No.- 420;504'; filed November 26, 194-1, now abandoned.

It was later found by Boyer and Amick (application Seria'l'No. 542,445, filed June 27jl944, now Eat'ent' 2-;4341-78) that if thecationicagent was 2. colloidize'd, either alone or in conjunction with the chromable color or-the mordant, increased penetration and level dyeing could be obtained without. the presence of a-nonionic surface active agent.

In our earlier application, ,Ser'. No; 750,886., filed May 27, 1947, We have: described and claimed a metachrome process inwhich the colloidized cationic surface active agent is associated with the-other features. The first is the presencelofa salt of an alkaline earth metal such'asmagnesium sulfate and secondly a procedure in which the dye bath initially has'a pH sufiiciently high so that rapid chromation is prevented or retarded and the pH is, then progressively lowered: until final cromation results.

According to the present invention we have found that with certain chromable azo dyes, namely those which do not have a nitrogen containing group ortho to the azo. group, a marked increase in color strength is obtained if the, alkaline earth metal salt and initial high pH followed by a reduced pH is used without any cationic surface active agent. The alkaline earth metal salt in the present case as in the earlier application above referred to must of course have an anion which does not form complexes with chromium containing salts. The increase in strength is marked and there is no problem of scum formation. It is thus possible to obtain strengths which do not compare unfavorably with those obtained by the process of the copending application above referred to without requiring any cationic agent and hence encountering no problem of colored scum or floc formation.

It is not known why marked increase in strength is obtainable with th particular chromable azo dyes of the present invention without any cationic surface active agent. Many chromable colors of other types do not show any in? crease in strength unless a cationic surface active agent is used. It is not known whether the mechanism of dyeing with these particular azo dyes is different than that which occurs with some other chromable colors or whether theim proved result without a cationic surface active agent is due to other factors- It is, therefore,.not desired to limit the present invention to any theory of dyeing mechanism.

The invention will be described in. conjunction 3 with the specific examples and in connection with the drawings in which:

Figs. 1 to 9 are pairs of curves drawn by a recording spectrophotometer showing dyeing strengths with and without the presence of various alkaline earth metal salts. The parts are by weight.

Example 1 A dye bath was prepared comprising 2% of the dye having Color Index 203, 10% ammonium sulfate and 1% potassium bichromate in 400 ml. of distilled water. A -gram woolen piece or skein, pre-wet with distilled water, is entered into the dye bath which is gradually heated to the boil in about 30 minutes. The bath is then boiled for about 30 minutes, after which the volume of water is replenished and 2% acetic acid is added. Boiling is continued for another 30 minutes, the water volume again replenished and 4% of 28% acetic acid is added. Boiling is again continued for about 30 minutes after which the dyed wool is removed from the bath, rinsed in distilled water, squeezed and dried. During th dyeing the wool is turned intermittently to insure uniform dyeing. All percentages are based on the weight of the wool. This is the control dyeing and the procedure used is one that is often recom-- mended for dyeing chromable colors by the metachrome process.

A second dye bath is prepared comprising 2% of the dye having Color Index 203, 2% ammonium hydroxide, 340% magnesium sulfate containing 7 molecules of water of crystallization and 0.6% potassium bichromate in 400 m1. of distilled water. A 5-gram wool sample is entered into this bath and dyed as above. The color value of the wool sample dyed by this procedure is 322% compared to 100% for th control, both measurements being made on a recording spectrophotometer as shown in Fig. 1.

Example 2 The procedure of Example 1 is repeated exactly except calcium nitrate is substituted for the magnesium sulfate of Example 1. As will be seen from Fig. 2 the value of the dyeing made from the bath containing the calcium nitrate was 187%,,

compared to 100% for the control.

Ezcample 3 The procedure of Example 1 is repeated exactly except the magnesium sulfate is replaced with barium chloride. As Will be seen from Fig. 3, the color value of this dyeing is 321%, compared to 100% for the control dyeing.

Example 4 The procedure of Example 1 is repeated exactly except the magnesium sulfate is replaced by strontium salicylate. The color value for the dyeing of the wool made in this bath as obtained by the G. E. recording spectrophotometer is 226% as will be seen in Fig, 4. This compares with 100% for the control dyeing.

Example 5 Example 7 The procedure of Example 1 is repeated exactly except the dye is made by coupling diazotized 2-amino-4-nitrophenol to 4-sulfo beta naphthol. The color value of the wool dyed in the magnesium sulfate bath is 120% compared to for the control dyeing as will be seen in Fig. '7.

Example 8 The procedure of Example 1 is repeated exactly except the dye having Color Index 652 is used instead of the dye having Color Index 203. The color value of the wool dyed in the bath containing the magnesium sulfate is about 133% compared to 100% for the control as will be seen in Fig. 8.

Example 9 The procedure of Example 1 is repeated exactly except the dyeings are made on synthetic protein fiber from casein instead of wool. If the color value of the control dyeing is 100%, then th color value of the dyeing made from the dye bath containing the ammoniacal solution of magnesium salt is about 111%.

Example 10 The procedure of the preceding example is repeated exactly except the material dyed is silk instead of synthetic protein fiber from casein. If the color value of the control dyeing is 100% then the value of the dyeing obtained from the dye bath containing the ammonia and magnesium salt is about Example 11 'The procedure of the preceding example is repeated except the dyeings are made on nylon instead of silk. If the color value of the control dyeing is 100%, the value of the dyeing made from the dyebath containing the ammonia and magnesium sulfate is about 196 The comparison curves drawn by a recording spectrophotometer appear in Figure 9.

We claim:

1. A method of dyeing which comprises subjecting substantially unmetallized basic nitrogenous fibers to the action of a dye bath formed by mixing a chromable azo dye having nitrogen-free groups ortho to the azo group, a soluble alkaline earth metal salt the anion of which does not form complexes with chromium containing salts, a soluble chromium containing compound, water, and sufiicient alkali to make the bath alkaline and to cause said dye to react with said alkaline earth metal salt to form an alkaline earth metal complex of said dye and insufiicient to materially damage said fibers, partially dyeing said fibers from said complex at an elevated temperature, gradually lowering the pH of said bath to a point where decomposition of said complex and chromation of the dye take place, and completing the dyeing at said lowered pH.

2. A method of dyeing which comprises subjecting substantially unmetallized basic nitrogenous fibers to the action of a dye bath formed by mixing a chromable azo dye having nitrogen-free groups ortho to the azo group, magnesium sulfate, a soluble chromium containing compound, water, and sufiicient alkali to make the bath alkaline and to cause said dye to react with said alkaline earth metal salt to form an alkaline earth metal complex of said dye and insuflicient to materially damage said fibers, partially dyeing said fibers from said complex at an elevated temperature, gradually lowering the pH of said bath to a point where decomposition of said complex and chromation of the dye take place, and completing the dyeing at said lowered pH.

3. A method of dyeing which comprises subjecting wool fibers to the action of a dye bath formed by mixing a chromable azo dye having nitrogen-free groups ortho to the azo group, a soluble alkaline earth metal salt the anion of which does not form complexes with chromium containing salts, a soluble chromium containing compound, water, and sufiicient alkali to make the bath alkaline and to cause said dye to react with said alkaline earth metal salt to form an alkaline earth metal complex of said dye and insuflicient to materially damage said fibers, partially dyeing said fibers from said complex at an elevated temperature, gradually lowering the pH of said bath to a point where decomposition of said complex and chromation of the dye take place, and completing the dyeing at said lowered pH.

4. A method of dyeing which comprises subjecting wool fibers to the action of a dye bath formed by mixing a chromable azo dye having nitrogen-free groups ortho to the azo group, magnesium sulfate, a soluble chromium containing compound, water, and sufiicient alkali to make the bath alkaline and to cause said dye to react with said alkaline earth metal salt to form an alkaline earth metal complex of said dye and insufiicient to materially damage said fibers, partially dyeing said fibers from said complex at an elevated temperature, gradually lowering the pH of said bath to a point where decomposition of said complex and chromation of the dye take place, and completing the dyeing at said lowered pH.

5. A method of dyeing which comprises subjecting wool fibers to the action of a dye bath formed by mixing a chromable azo dye having nitrogen-free groups ortho to the azo group, a soluble alkaline earth metal salt the anion of which does not form complexes with chromium containing salts, a soluble chromium containing compound, water, and suflicient alkali to make the bath alkaline, but with a pH not greater than 9.5, and to cause said dye to react with said alkaline earth metal salt to form an alkaline earth metal complex of said dye and insufilcient to materially damage said fibers, partially dyeing said fibers from said complex at an elevated temperature, gradually lowering the pH of said bath to a point where decomposition of said complex and chromation of the dye take place, and completing the dyeing at said lowered pH.

6. A method of dyeing which comprises subjecting wool fibers to the action of a dye bath formed by mixing a chromable azo dye having nitrogen-free groups ortho to the azo group, magnesium sulfate, a soluble chromium containing compound, water, and suificient alkali to make the bath alkaline, but with a pH not greater than 9.5, and to cause said dye to react with said alkaline earth metal salt to form an alkaline earth metal complex of said dye and insufiicient to materially damage said fibers, partially dyeing said fibers from said complex at an elevated temperature, gradually lowering the of said bath to a point where decomposition of said compleX and chromation of the dye take place, and completing the dyeing at said lowered pH.

'7. A method according to claim 5 in which the azo dyestufi has the formula I SOaH 8. A method according to claim 5 in which the azo dye is dye No. 203 of the color index.

9. A method according to claim 5 in which the azo dye is dye No. 652 of the color index.

10. A method according to claim 1 in which the pH of the dye bath is lowered by the addition of successive small portions of acid.

11. A method according to claim 2 in which the pH of the dye bath is lowered by the addition of successive small portions of acid.

12. A method according to claim 3 in which the pH of the dye bath is lowered by the additions of successive small portions of acid.

13. A method according to claim 4 in which the pH of the dye bath is lowered by the additions of successive small portions of acid.

14. A method according to claim 5 in which the pH of the dye bath is lowered by additions of successive small portions of acid.

15. A method according to claim 6 in which the pH of the dye bath is lowered by the additions of successive small portions of acid.

CHESTER A. AMICK. WILLARD H. WATKINS. HENRY E. MILLSON.

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

OTHER REFERENCES Application of Dyestuffs, by J. M. Matthews, published in New York by John Wiley & Sons, 1920, pages 356-358.

Metachrome Method of Dyeing, by C. H. A. Schmitt, article in Amer. Dyes. Rep. for June 26,

1939, pages P336-P341.

Theory and Practice of Wool Dyeing, by C. L. Bird, published 1947 in London by Society of Dyers and Colourists, pages 87, 88.

Application of Coal Tar Dyestuffs, by C. M. Whittaker, published 1919 in London by Bailliere, Tindall and Cox, pages 59, 60, 61.

Claims

1. A METHOD OF DYEING WHICH COMPRISES SUBJECTING SUBSTANTIALLY UNMETALLIZED BASIC NITROGENOUS FIBERS TO THE ACTION OF A DYE BATH FORMED BY MIXING A CHROMABLE AZO DYE HAVING NITROGEN-FREE GROUPS ORTHO TO THE AZO GROUP, A SOLUBLE ALKALINE EARTH METAL SALT THE ANION OF WHICH DOES NOT FORM COMPLEXES WITH CHROMIUM CONTAINING SALTS, A SOLUBLE CHROMIUM CONTAINING COMPOUND, WATER, AND SUFFICIENT ALKALI TO MAKE THE BATH ALKALINE AND TO CAUSE SAID DYE TO REACT WITH SAID ALKALINE EARTH METAL SALT TO FORM AN ALKALINE EARTH METAL COMPLEX OF SAID DYE AND INSUFFICIENT TO MATERIALLY DAMAGE SAID FIBERS PARTIALLY DYEING SAID FIBERS FROM SAID COMPLEX AT AN ELEVATED TEMPERATURE, GRADUALLY LOWERING THE PH OF SAID BATH TO A POINT WHERE DECOMPOSITION OF SAID COMPLEX AND CHROMATION OF THE DYE TAKE PLACE, AND COMPLETING THE DYEING AT SAID LOWERED PH.