Identification of Newer Types of Reactive Dyes on Cellulosic

FRANK JORDINSON and RONALD LOCKWOOD

Dyeing and Finishing Section Department of' Textile Industries Huddersfield Polytechnic Huddersfield HDl 3DH

The reactive systems and chromogens present in further types of reactive dye are briefly discussed. Dyeings, or prints, on cotton of selected dyes in each range, including more black reuctive dyes, have been tested to distinguish between the various types of reactive dye. Special attention is paid to methods of detecting the presence of metals in reactive dyeings.

This is the final paper in a series dealing with the identification of reactive dyeings on cellulosic fibres. The tendency noted in our last paper [ l ] for developments in reactive dyes to take the form of modifying existing reactive systems to give dyes suitable for particular dyeing or printing processes has con- tinued. Some firms market the same dye under two different names to indicate its suitability for application by more than one specific technique in dyeing or printing. Also, a number of reactive dyes have been withdrawn as part of a policy of rationalisation leading to the production of dye ranges broadly intended for:

(a) Exhaust dyeing methods (with hot or warm fixation) (b) Continuous dyeing processes and printing, also with hot or

warm fixation.

As might be expected these newer ranges of reactive dyes follow the previously noted pattern of behaviour when dyeings or prints on cotton are subjected to a systematic scheme of identification.

This paper describes the results of a further detailed study of the identification of metals in dyeings of reactive dyes. The testing methods already described [ l ] were used on new ranges (see below), and were extended to all available dyeings (or prints) previously examined, where the presence of a metal was either known or suspected. We also used special metal-ion test papers [ 2 ] for supplementing or corroborating infor- mation gained by using the usual reagents for detecting chromium, copper, cobalt and nickel. When the test papers were used, exactly the same procedure was followed for ashing the dyed sample and obtaining a test solution as that described previously [ I ] . One portion of each extract was tested with the reagent solutions and another portion with the metal-ion test papers. Detailed instructions for using the specific metal-ion test papers are as follows:

Chronziunz (Cr04 '-) - Make the test solution alkaline with an excess of aqueous 10% sodium hydroxide solution. Dip the

Fibres - IV

test paper partly into the liquid for a few seconds, and then immerse in dilute nitric acid. If chromium is present, the paper becomes violet, the colour deepening on immersion in the nitric acid. In the absence of chromium, the paper may become violet but the colour disappears immediately on immersion in the nitric acid.

Copper (Cu") - Dip the test paper partly into the test solution, acidified with hydrochloric acid. Remove, dry in air for a few minutes and then immerse in a 10% aqueous solution of sodium (or ammonium) fluoride (NaF). In the presence of copper, the paper turns an intense reddish violet immediately, and the colour deepens on exposure to the air. In the absence of copper, the paper becomes white or almost white after immersion for a few minutes in the fluoride solution.

Cobalt (Co") - Dip the test paper partly into the test solution, acidified with mineral acid. Remove and expose the paper to ammonia fumes until the colour that first appears has disappeared, and then wave vigorously in the air for several minutes. I f cobalt is present the paper becomes blue or greenish blue, but in the absence of cobalt it remains almost colourless or yellow.

Nickel (Ni") - Make a small portion of the test solution alkaline with aqueous ammonia and filter. Immerse the test paper in the filtrate, remove after 1-2 s and expose to the air. In the presence of nickel the paper becomes pink-violet. In the absence of nickel the paper remains white. (NB. As a general instruction, when using all metal-ion test papers, where the acidity of the solution obtained with hydrochloric or nitric acid is not specified as weak or strong, take it to be about 10%

The results of the tests for metals are shown in Table 1. I t should be emphasised that the amounts of metal present in reactive dyeings on cellulosic fibres are extremely small; that freshly prepared solutions of Analar reagents should be used for testing; and that any colorations obtained using these reagents should be checked against blanks using distilled water in place of the solutions from the reactive-dyed samples.

Our experience with the metal-ion test papers was incon- clusive, although in the main the results supported those obtained using the specific reagents. With chromium, and to a less extent with copper, confusion arose because with some dyeings, when the appropriate coloration (on the test paper) indicated the presence of a metal, this coloration largely or completely disappeared when the paper was immersed in the final solution, i.e. nitric acid for chromium or alkali fluoride for copper. This would suggest absence of metal. Judging from the results with dyeings known to contain chromium or copper (from information in the Colour Index [3j or from positive results obtained using the specific reagents), we conclude that initial development of an intense coloration on the test paper for chromium or copper should be taken as indicating the presence of these metals, i.e. any loss of colour when the paper is immersed in the final reagent should be

wt/vol.)

JSDC February 1974 55

TABLE 1

Presence of Metals

Yellows Oranges Reds Violets Blues

Greens Browns Blacks

Copper

98t 4, 7, 1st 7, 11,18, 21, 23, 48, 637, 71t, 83, 84, 92, 106t, 113t, 1161 2,13t

9, 10, 22t, 31

Chromium

221 47t

Cobalt Nickel

48

62

4

(a) The figures are the appropriate C.I. Reactive Numbers (b) *Both chromium and cobalt are present in C.I. Reactive Black 1 (c) In every case the metal was indicated by using the appropriate

specific reagents. Those dyes marked t also gave a positive result with the test papers

ignored. Very few dyeings were examined which contained cobalt or nickel, and again the specific reagents for these metals proved to be more sensitive and more reliable than the metal-ion test papers.

Four more ranges of reactive dyes have been examined using dyeings on cotton and following the same general procedure as that described earlier [4]. As before, these dyeings were approximately 111 depth except for the blacks, which were approximately 2/ 1.

Sumifix Dyes These interesting dyes are manufactured by the Sumitomo Chemical Co. Ltd, Osaka, Japan. The chromogens are listed in the Colour Zndex and for a few dyes the reactive system is given as vinyl sulphone. The reactive system in many of the other dyes is probably vinyl sulphonyl also, but the chemical

TABLE 2

Behaviour of Sumifur Dyes*

Test Yellow R Brilliant (C.I. Reactive Yellow FlOG Yellow 77) (C.I. Reactive (monoazo) Yellow 78)

(aminoketone)

Boil for 2 min in 5% NaOH (Clayton) Much LC Complete LC

(GS 1)

4

Hoechst solvents test 4 Acid cross-dyeing Very slight LC Very slight LC

(GS 4-5) (GS 4-5) Very slight SW N o SW (GS 4-5) (GS 5)

1;ormosul G Permanently Unaffected (Clayton) decolorised

Acid stannous As above As above chloride (FH)

Alkaline dithionite ( 'Ihumm and Benz)

Brilliant Scarlet R

structures of the Sumifix dyes are different from those of the Renlazol (FH) dyes [5]. The chromogens in the 20 dyed samples received were either azo or anthraquinone except for Sumifix Brilliant Yellow F 10G (C.I. Reactive Yellow 78), which is an aminoketone.

Dyeings on cotton of six of these dyes were tested and the results are given in Table 2.

All the dyeings were completely resistant to the Hoechst solvents and, like other vinyl sulphone dyes, were also fast to cross-dyeing. The resistance to boiling sodium hydroxide (2 min), however, was distinctly poor and longer treatment (10 min) caused complete removal of dye.

Procion H-E Dyes At present (1973) this i8 a small range, believed to be bis-monochlorotriazinyl dyes, i.e. having two cyanuric chloride residues with one chlorine atom in each. The dyes are highly substantive to cellulose and are, therefore, suitable for exhaust dyeing techniques. Three Procion H-E dyes, each based on the azo chromophore, were tested (see Table 3).

The dyeings showed marked variations in resistance to the tests employed. The yellow had the highest resistance to the Hoechst solvents and to acid cross-dyeing but, in the sodium hydroxide test, the red was much more resistant than the yellow or blue.

Levafur E-A Dyes I t is 13 years since Bayer marketed the original Levafix E dyes (1961), for application to cellulosic fibres by exhaust methods or by cold pad-batch processes. The Levafix E-A dyes were recently introduced as general-purpose reactive dyes, which may be used along with other ranges (Levafix E, P, or P-A dyes) in various techniques for dyeing cellulosic fibres. Their reactive system is not stated in the Colour Index, nor, except in a few cases, are the chromogens. As some Levafix E-A dyes listed as azo dyes were duplicated by another dye manu- facturer it was decided to include only one such dyeing (C.1.

Brilliant Brilliant Brilliant Red 7BF Violet B Blue BB

(C.I. Reactive (C.I. Reactive (C.I. -Reactive (C.I. Reactive Red 113) Red 114) Violet 22) Blue 101) (monoazo) (monoazo) (anthraquinone) (anthraquinone)

Orange-brown Much LC Much LC Much LC in the alkali (GS 1) (GS 1-2) (GS 1-2) much LC (GS 1-2) No staining of white cotton * Completely resistant (No LC) Very slight LC (GS 4-5) (GS 5) Slight SW No SW (GS 4) (GS 5) Permanently Permanently decolorised decolorised

Slowly decolorised As above No change with persulphate

No LC but bluer N o LC but much redder (GS 5) No SW (CS 5 ) Permanently decolorised

Slowly decolorised N o change with persulphate Pink. Pale purple on rinsing

No LC (GS-5)

N o SW (GS 5 )

Yellow-brown Greyish-blue with persulphate Purple then yellow Pale blue with persulphate Green. Blue on rinsing

*GS = Grey Scale LC = Loss of colour SW = Staining of wool

56 JSDC February 1974

TABLE 3

Behaviour of Procion H-E Dyes*

Test Yellow H-E3G Red H-E3B Blue H-E6R (C.I. Reactive Yellow 81) (am) (azo) (azo)

(C.I. Reactive Red 120) (C.I. Reactive Blue 108)

Boil for 2 min in 5% NaOH (Clayton) No staining of

Much LC (GS 2)

white cotton

Hoechst solvents test N o LC ( G S 5) Acid cross-dyeing Slight LC (GS 4) test (Bode) SW (GS 3-4) Formosul G (Clayton) Permanently

decolorised

Acid stannous As above chloride (EH)

Some LC (GS 3-4B) Colour yellower Slight staining of in the alkali white cotton No staining of white cotton Some LC (GS 3-4) Some LC (GS 3) SW (2-3) SW (GS 2) Pale yellow Permanently Pale orange brown decolorised with persulphate Permanently As above decolorised

Much LC (GS 1-2G)

Slight LC (GS 4G) Some LC (GS 3-4R)

*GS = Grey Scale LC = Loss of colour SW = Staining of wool

TABLE 4

Behaviour of Levafix E-A Dyes" w

Test

Boil for 2 min in 5% NaOH (Clayton)

Orange E-3GA Turquoise Blue (C.I. Reactive E-BA Orange 64) (C.I. Reactive (azo) Blue 11 6)

LC (GS 3-4Y) Slight LC Colour is (GS 4R) purple in the alkali

Hoechst solvents test Acid cross-dyeing test (Bode)

Formosul G (Clay ton)

Acid stannous chloride (FH)

- Slight LC (GS 4D) Slight LC (GS 4D) S W (GS 4) Decolorised Yellow with persulphate As above

Alkaline dithionite (Thumm and Benz) Conc. HNO, and acid stannous chloride (E'H)

Very slight LC (GS 4-5R) Some LC (GS 3G) No SW (GS 5)

Blue-grey Bright green with persulphate Navy blue then almost decolorised Bright green with persulphate Purple. Original colour on rinsing Bright green then purple

*GS = Grey Scale LC = Loss of colour SW = Staining of wool

Reactive Orange 64) out of the six dyeings on cotton chosen for testing. The remaining five dyeings were blues or greens, but, as all six dyeings behaved similarly in the various tests, they may be taken as typical representatives of the Levafix E-A range. The results are shown In Table 4.

With one exception (C.I. Reactive Green 16) the dyeings were reasonably fast to acid cross-dyeing and to boiling 5% sodium hydroxide. This supports the claim of the makers that Levafut E-A dyes have very good wet-fastness properties. They are certainly faster to boiling alkali than Levafix E dyes; also to acid cross-dyeing with respect both to staining on to white wool and to loss in depth. Attention is drawn to the behaviour after chemical reduction of two Levafix E-A dyeings, viz. Turquoise Blue E-BA (C.I. Reactive Blue 116) and Brilliant Green E-5BA (C.l. Reactive Green 21). These are phthalo- cyanine dyes but the intensity of the bright green which develops on re-oxidation with persulphate is very unusual. All

Brilliant Blue Navy Blue Brilliant Green E-BRA E-4RA E-5 BA (C.I. Reactive (C.I. Reactive (C.I. Reactive Blue 114) Violet 23) (azo) Green 21)

Very slight LC Slight LC Very slight LC (GS 4-5R) (GS 4G) (GS 4-5)

Redder in alkali

No staining of white cotton Very slight LC Some LC Slight LC ( G S 4-5) (GS 3-4G) (GS 4G) Slight LC (GS 4) Very slight LC Very slight LC Some SW ( G S 3) (GS 4-5) (GS 4-5G)

SW (GS 3-4) Nu SW (GS 5) Orange brown Permanently Pale green Greyish blue decolorised Bright green with persulphate with persulphate Brown then yellow As above Blue with almost decolorised persulphate Bright green with

Olive green Purple. Original Blue on rinsing Yellowish brown Bright green N o change with then purple stannous chloride

b

Navy blue then

persulphate

colour on rinsing

Dark Green E-3BLA (C.I. Reactive Green 16)

Much LC (GS 1-2) Slight staining of white cotton (greenish blue)

Slight LC (GS 4R)

Much SW (GS 2)

Dull purple Pale grey green with persulphate Purple then almost decolorised No change with persulpha te Red. Purple on rinsing Yellowish brown then pale green

LC (GS 2-3R)

other phthalocyanine reactive dyeings when so treated give a pale greenish blue.

Drimarene R Dyes These comprise one of the specialist ranges of highly reactive dyes developed by Sandoz and are intended for continuous dyeing processes and for printing. The range is extensive and embraces the usual chromogens, e.g. azo, metallised azo, anthraquinone and phthalocyanine, as mentioned in the Colour Index. The reactive system is not stated but it is identical with that of some modern Levafix dyes (P-A and E-A), as many members of these ranges have the same C.I. generic names as Drimarene R dyes.

Six dyeings on cotton were tested (see Table 5). Except for C.I. Reactive Red 119, the dyeings showed good resistance to boiling sodium hydroxide. They were not completely resistant to the Hoechst solvents and the fastness to acid

JSDC February 1974 57

TABLE 5

Behaviour of Drimarene R Dyes*

Boil for 2 min in 5% NaOH (Clayton)

Hoechst solvents test Acid cross-dyeing test (Bode) k’ormosul G (Clayton )

Acid stannous chloride (FH)

Yellow R-GL Orange R-GL (C.I. Reactive (C.I. Reactive Yellow 83) Orange 62) (azo) (monoazo)

N o LC (GS 5) No LC but redder (GS SR) -

Slight LC LC (GS 3R) (GS 4) Some LC (GS 3-4) Slight SW (GS 4) Permanently Decolorised (slowly) decolorised (slowly) Pale

Some LC (GS 3-4) Some SW (GS 3)

orange brown with persulphate

Orange brown with persulphate

As above Decolorised

Alkaline dithionite (Thumm and Benz)

Conc. HNO, and acid stannous chloride (FH)

* G S = Grey Scale LC = Loss of colour SW = Staining of wool

cross-dyeing varied appreciably.

Brilliant Red Brilliant Blue Turquoise R-B Blue R-3GL R-ZGL R-RL (C.I. Reactive (C.I. Reactive (C.I. Reactive (C.I. Reactive Blue 106) Blue 1 1 3) (monoazo Red 119) Blue 103) (phthalocyanine) metallised) (monoazo) (anthraquinone)

LC (GS 2-3) Very slight LC Slight LC Slight LC Duller and (GS 4-5) (GS 4) (GS 4R) browner No staining of white cot ton LC (GS 3-4) LC (GS 3-4) LC (GS 2-3) LC (GS 3 -4R)

.)

Some LC (GS 3-4) Some SW (GS 3) Y eWow No change with persulphate

Almost decolorised Pink with persulphate

Table 6 summarises the behaviour of the four ranges of reactive dyes (a) with boiling 5% sodium hydroxide, (b) with Hoechst solvents and (c) in acid cross-dyeing.

Identification of Black Reactive Dyeings Five more black reactive dyeings (or prints) on cotton have been examined and differentiated by the detailed procedure given in Part 11 [6]. The results (Tables 7 and 8) placed two blacks in Table 7, one in Section A and one in Section B. Of the remaining blacks, one (Sumifix Grey MG) fell into Table 8A and the others in Table 8B.

NB. The numbering of Table 7 (A and B) and Table 8 (A and U ) corresponds exactly to that used in the relevant tables in Part 11 [ 61 and Part 111 [ 1 ] .

The results of the present tests and those reported earlier [ 1, 61 can be sunimarised as follows:

Table Number of dyes

7A 3 7 8 7 XA 6 8B 20

Driniarene Black K-2BL was originally listed as C.I. Reactive Black 35 but was later changed to C.1. Reactive Black 34, which appears in Table 7B as Levafix Black P-3GL. These two dyes. although very similar, are not identical. In the nitric acid \pot tirig t e s ~ 111t.y gave distinctly different results, viz. a redder spot with i f i t Levafix dye and a greener spot with the I)rintarenc dye .

TABLE 6

Much LC (GS 2) Some SW (GS 3) Yellow Dull purple with persulphate

Reddish brown then yellow Grey blue with persulphate Green Grey blue on rinsing

Slight LC (GS 4G) Much LC ( G S 2-3R; No SW (GS 5 ) Much SW ( G S 2 -3 ) Purple then Almost decolorised

Faint brown bluish grey Pale greenish blue with persulphate with persulphate Purple then almost decolorised Green blue with persulpha te Purple Original colour on rinsing Bright green

As above

then purple

Behaviour of Dyeings in Three Tests

Range Boiling 5% Hoechst Acid cross- NaOH solvents test dyeing test

Sumifix Not resistant Resistant Resistant Procion H-E Not resistant Variable Variable

(Staining of white wool) Variable Levafix E-A Resistant Resistant

(except dark (except navy (white wool stained - green) blue) except turquoise

and green)

stained - except turquoise)

Drimarene R Resistant Variable Variable (white wool

Conclusions The results of extensive tests for metals in reactive dyeings suggest that the metal-ion test papers which were tried are not as sensitive as the usual specific reagents.

Four more ranges of reactive dyes have been examined and five more black reactive dyes have been differentiated. The Hoechst solvents test, together with Bode’s acid cross-dyeing test [4] and the boiling sodium hydroxide test [7], continued to provide useful information. However, the newer ranges of reactive dyes did not withstand the Hoechst solvents as well as the earlier types, which, except for a few phthalocyanine dyes, were completely resistant. The Hoechst confirmatory test for reactive phthalocyanine dyeings [4] was reliable for some dyeings but unreliable for others. The Thumm and Benz test [8] distinguished between phthalocyanine and anthraquinone reactive dyeings. In the latter case, as stated by Thumm and Benz, more severe reduction caused irreversible decomposition and the original colour could not be restored by oxidising agents.

58 JSDC February 1974

TABLE 7

Black Reactive Dyes Withstanding* Zmin Boil in 5% NaOH Commercial C.I. Chromogen Metal found Conc. nitric acid Conc. sulphuric Reduction Conc. name Reactive specific test spotting acid steep test (acid hydrochloric

Black reagent paper pattern stain on on stannous acid spotting filter extract dilution chloride) pa per

( A ) Dyes that show little or no staining of wool in the acid cross-dyeing test (Bode), i.e. rating 4, 4-5 , or 5 on Grey Scale for Assessing Staining Reacna Grey 2 8 Monoazo Cr Cr Violet Grey Pale Unchanged Slowly Violet C-BR (metal- brownish in tone decolorised

(B) Dyes that show definite staining of wool in the acid cross-dyeing test (Bode), i.e. rating d 4 on Grey Scale for Assessing Staining

complex) violet

Azo None None Redder Violet Reddish Greenish Levafix Black 34 P-3GL in tone violet blue

*Effect on pattern rating d 4 on Grey Scale for Assessing Change in Colour

TABLE 8

Black Reactive Dyes not Withstanding* 2-min Boil in 5% NaOH Commercial C.I. Chromogen Metal found Conc. nitric acid Conc. sulphuric name Reactive specific test spotting acid steep

Black reagent paper pattern stain on on filter extract dilution paper

Brown then Redder decolorised in tone

Reduction Conc. test (acid hydrochloric stannous acid spotting chloride)

(A) Dyes that 8how little or no staining of wool in the acid cross-dyeing test (Bode), i.e. rating 4, 4-5, or 5 on Grey Scale for Assessing Staining

Sumifix 30 Monoazo None None Greenish None Violet Faint Redder then Bright Grey MG brown with purple decolorised purple

purple rim

(B) Dyes that show definite staining of wool in the acid cross-dyeing test (Bode), i.e. rating < 4 on Grey Scale for Assessing Staining

Reacna 29 Monoazo Cr Cr Pale Black (metal- yellowish C-BK complex) brown Levafix Grey 33 Azo Cr Cr Bluish P-KL red

*Effect on pattern rating < 4 on Grey Scale for Assessing Change in Colour

We thank those organisations that supplied dyeings or prints of reactive dyes for this work.

(MS. received 23 May 1973; revised MS. received 8 August I 9 73)

References

1. 2.

Jordinson and Lockwood, J.S.D.C., 88 (1972) 117. J . T. Baker Test Papers for Ions (J. T. Baker Chemical Co., Phillipsburg, New Jersey, U.S.A.) distributed by Linton Products, Hysol, Harlow, Essex.

Pale Blue Faint Slowly Slightly yellowish violet decolorised redder brown Purple Bluish Faint Redder then Dull

grey violet decolorised purple

3.

4. 5. 6. 7.

8.

‘Colour Index’ (Bradford: Society of Dyers and Colour- ists, 3rd edn, 197 1). Jordinson and Lockwood, J.S.D.C., 84 (1968) 205. Sumitomo Chemical Co., private communication. Jordinson and Lockwood, J.S.D.C., 86 (1970) 524. Clayton, ‘Identification of Dyes on Textile Fibres’ (Bradford: Society of Dyers and Colourists, 2nd revised edn, 1963). Thumm and Benz, Amer. Dyestuff Rep., 55 (1966) 15.

JSDC February 1974 59