AUTEX Research Journal, Vol. 3, No2, June 2003 © AUTEX

http://www.autexrj.org/No2-2003/0055.pdf

NOVEL REACTIVE RED DYES Edyta Matyjas, Edward Rybicki Technical University of Lodz Department of Textile Finishing Zeromskiego 116, 90-534 Lodz, Poland Abstract

Dyes with two monochlorotriazine or with two monochlorotriazine and two vinylsulphone reactive groups have been investigated for establishing an enhancement of the dyeability of cotton fabrics. The effect of the diamine bridge linking two chromophore systems on the degree of dye exhaustion from the dyebath and dye bonding with the cellulose fibre was examined. The excellent water solubility of these dyes make them useful in the exhaustion method of dyeing. The kind of diamine used as a bridging group has a significant influence on exhaustion and fixation values. The application of diamine, which assures the chemically linear structure of the dye, affects the increase in the amount of the dye fixed on the fibres. Apart from the derivatives of ethylene-1,2-diamine and phenylene-1,2-diamine, the remaining dyes are characterised by a very high degree of dye exhaustion from the dyebath. The dyes examined can be successfully used for dyeing cellulose fibres by the exhaustion process.

Keywords

fibre-reactive dyes, bi-functional reactive dyes, bridging group, cellulosics fabrics, dyeing, exhaustion, fixation

Introduction Commercially reactive dyes were used for the first time over [[35 years ago]]. Their structure is attributed to chemical bonding between suitable groups in the dye molecule and hydroxyl groups in the cellulose fibre. Before the introduction of reactive dyes, cotton was often dyed with direct, vat, sulphur and azoic dyes. For about four decades before the use of reactive dyes, these dyes remained the only feasible method of achieving dyeings of high fastness to wash cellulose textiles. The characteristic structural features of a typical reactive dyes molecule are: the reactive system, enabling the dyes to form covalent bonds between the dye and the

substrate, the chromophoric grouping, contributing to the colour and much to the substantivity for

cellulose, a bridging group that links the reactive system to the chromophore, and solubilising groups.

The reactive grouping is attached directly to the chromophore, and most reactive systems contain a heterocyclic ring which contributes to substantivity for cellulose. The nature of the bridging group and other substituents on the heterocyclic ring greatly influences the reactivity and other dyeing characteristics of reactive dyes. Many reagents can be used as a reactive system, but only a few have met the requirements to become commercially established in a significant segment of the market. The chlorotrazinyl and vinylsulphone groups have been firmly established as the main reactive system for cellulose. Dye manufacturers have for a long time recognised the need to improve the fixation levels of reactive dyes. As a result some of the reactive dyes with more than one reactive group in the dye molecule have been investigated. Reactive systems are often classified according to the number of reactive groups contained in the dye molecule, as mono-, bi- and poly-functional reactive systems. Experimental We examined the three series of bi-functional reactive dyes based on 1-amine-8-hydroxynephthalene-3,6-disulphonic acid, with either a monochlorotriazine reactive system or with monochlorotriazine and

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vinylsulphone groups lying on the opposite site of the dye chromophore, linked by a diamine unit and disposed between the triazine rings. The structure of the obtained dyes is shown by the general formula:

Dw

N

NN NH

NOH

NA

SO3NaNaO3S

ClN

NNNH

NOH

NA

NaO3S SO3Na

Cl

Figure 1. The general formula of reactive dyes where: A – the active component;

A-1 orthanilic acid A-2 anthranilic acid A-3 4-(β-ethylsulphate)sulphonylaniline

Dw – diamines;

Dw-1 phenylene-1,2-diamine Dw-2 phenylene-1,3-diamine Dw-3 phenylene-1,4-diamine Dw-4 diaminestilbene-2,2'-disulphonic acid Dw-5 4,4'-diaminebenzoanilide Dw-6 ethylene-1,2-diamine

The dyes were subjected to spectrophotometric analysis and assessment of the λmax in an acetone-water 2:1 solution and a 25% pyridine solution by means of a Spekol 11 spectrophotometer, made by Carl-Zeiss Jena, Germany. The dye concentration in solution was 25 mg/dm3.The content of the salt in the dyes was determined by potentiometric titration. The structure of the dyes and the results of spectrophotometric measurements are listed in Table 1: Table 1. Dyes structures, dye content and spectrophotometric properties of dyes

dye structure λmax, nm dye

diazo component diamine dye content, %

acetone:water (2:1) 25% pyridine

R-1 A-1 Dw-1 72.3 542 540 R-2 A-1 Dw-2 56.1 542 540 R-3 A-1 Dw-3 58.0 542 540 R-4 A-1 Dw-4 62.1 542 540 R-5 A-1 Dw-5 36.7 542 540 R-6 A-2 Dw-1 34.0 520 550 R-7 A-2 Dw-2 38.3 550 550 R-8 A-2 Dw-3 31.9 550 550 R-9 A-2 Dw-4 54.5 550 550 R-10 A-2 Dw-5 43.4 550 550 R-11 A-2 Dw-6 47.5 550 550 R-12 A-3 Dw-1 33.9 520 520 R-13 A-3 Dw-2 34.4 518 521 R-14 A-3 Dw-3 36.1 522 524 R-15 A-3 Dw-4 44.1 520 524 R-16 A-3 Dw-5 40.6 522 522 R-17 A-3 Dw-6 29.9 518 522

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Dye application Bleached cotton fabric was used in the dyeing experiments after washing in an aqueous solution of 2 ml/dm3 non-ionic detergent (Precolor Jet). The fabrics were rinsed several times in water and dried at room temperature. The fabric samples were dyed in a BFA-12 Mathis Labomat laboratory dyeing machine manufactured and granted us by Warner Mathis AG Textile Machines, Switzerland, in a dyebath containing 1% (o.w.f.) dye and a 10:1 liquor ratio. The dyebath contained 40 g of NaCI and 10 g of Na2CO3 per 1 dm3 of the dyebath. All fabrics were wetted out in cold water before the dyeing process was carrying out. The dyed samples were dried at room temperature. The temperature course of the dyeing process is shown in Figure 2.

Figure 2. Temperature course of the dyeing process Determination of dye exhaustion and fixation The extent of exhaustion achieved for a 1% dyeing on cotton fibres was determined using spectroscopic analysis of the dye bath before and after dyeing at different times. The calibration curve for each dye was determined by measuring the absorbance of the dye solution of known concentrations. The changes in absorbance versus concentration for each dye in an acetone:water 2:1 solution, as well as in 25% pyridine solution. were plotted. The percentage of dyebath exhaustion achieved for each dye was calculated from the following formula:

%cccE 100

1

21 ⋅−

= (1)

where: E- the degree of dye exhaustion from the dyebath, in percent,

1c , 2c - the concentration of the dye before and after dyeing, respectively. The absorbed but unfixed dye on the cellulose fibres was removed by repeated extraction with a 25% pyridine solution. Next, the fabric was rinsed in water and dried at room temperature. This allowed us to determine the degree of dye fixed on the fibre. The dye fixation ratio was estimated using two methods: − the difference between the quantity of dye in fibre and that dissolved in the pyridine solution was

used to determine the degree of dye fixation ratio. The percentage dye fixation ratio for each dye was calculated from the following formula:

%ccT 100

2

1 ⋅= (2)

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where: T- the fixation ratio determined by method 1, in percent,

1c , 2c - the concentration of the dye after and before extraction respectively. − the reflectance values of each dyed sample were measured before and after extraction in a

pyridine solution with a Macbet Colour Eye 3000 spectrophotometer, a product of a division of the Kollmorgen Corporation, Newburgh, USA. The percentage dye fixation ratio for each dye was calculated using the following formula:

( )( ) %

S/KS/KT S/K 100

2

1 ⋅= (3)

where: TKIS - the fixation ratio determined by method 2, in percent,

( )1/ SK , ( )2/ SK - the colour strength values of dyed samples after and before extraction respectively.

From the result of the dye exhaustion and fixation ratio, the fixation yield was calculated for all dyeings by the given formula:

%ETF100

⋅= (4)

where: F - the fixation yield, in percent, E, T - the degrees of dye exhaustion and dye fixation ratio respectively, in percent. Primary exhaustion - the percentage of the dye absorbed onto the fibre before the addition of sodium carbonate, relative to the amount of the dye used for experiment; Secondary exhaustion - the percentage of the dye absorbed or chemically bound to the fibre at the end of the dyeing process but before extraction with pyridine solution, relative to the amount of the dye used for experiment; Fixation ratio - the percentage of the dye chemically bound to cellulose at the end of the dyeing process, relative to secondary exhaustion; Fixation yield - the percentage of dye chemically bound to cellulose at the end of the dyeing process, relative to the amount of dye used for the experiment. The results of dye exhaustion and fixation values were shown in Table 2.

Table 2. Degrees of dye exhaustion from the dyebath and the dye fixation ratio and the fixation yield

Degree of exhaustion, % Fixation ratio, % Dye Primary

exhaustion, % Secondary

exhaustion, % Method I Method II

Fixation yield, %

R-1 21.9 41.3 83.8 77.4 34.6 R-2 53.9 86.9 64.2 73.4 55.4 R-3 76.2 86.3 63.9 68.9 55.1 R-4 53.9 78.9 81.6 82.1 70.9 R-5 32.5 60.1 76.4 76.6 67.5 R-6 44.3 50.9 59.8 52.6 30.3 R-7 87.9 94.9 76.8 76.9 72.8 R-8 79.0 91.5 91.8 92.2 77.6 R-9 79.6 84.5 64.3 69.7 54.3 R-10 67.5 72.3 97.0 64.8 48.4 R-11 60.6 64.4 58.1 87.2 37.4 R-12 39.5 72.3 94.8 94.6 68.5 R-13 53.2 81.4 94.6 95.8 76.9 R-14 34.7 66.2 90.4 91.8 59.9 R-15 41.3 66.9 95.4 97.2 63.8 R-16 35.6 54.4 92.3 91.3 50.2 R-17 21.7 44.6 89.4 86.5 39.9

where:

for dyes delivered from orthanilic acid for dyes delivered from 4-(β-ethylsulphate)sulphonylaniline for dyes delivered from anthranilic acid

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Figure 3 shows the plot of primary and secondary exhaustion degree from the dyebath. The plot of the fixation values of the dyes is shown in Figure 4.

Figure 3. Plot of the primary and secondary exhaustion degree from dyebath

Figure 4. Plot of fixation ratio and fixation yield Results and Discussion The derivatives of 1-amine-8-hydroxynaphtalene-3,6-disulphonic acid are red dyes which showed high water solubility due to the presence of many sulphonic groups (from 6 to 8) and their symmetric arrangement in the dye molecule. Their excellent solubility in water makes it possible to carry out the application process with the low liquor ratio of 1:10 using 40 g of NaCI per 1 dm3 of the dyebath. With

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an increased molecule size of the dyes examined, an increasing substantivity to cellulose fibres was observed. The kind of active compound used in chromophoric grouping has a great influence on exhaustion and fixation values. The bi-functional reactive dyes (the derivatives of anthranilic acid (R-6 - R-11)) show the highest secondary exhaustion degree from the dyebath. As expected, the derivatives of 4-(β-ethylsulphate)sulphonylaniline dyes showed the lowest secondary exhaustion degree values due to the presence of vinylsulphone reactive groups in the dye molecule. Despite the low exhaustion from the dyebath, these dyes (R-12 to R-17) showed the highest fixation ratio, starting from 89% for derivative of ethylene-1,3-diamine to 95% for derivative of diaminestilbene-2,2'-disulphonic acid. The kind of diamines used as bridging groups influences the dyeing characteristics of the dyes examined. Among the derivatives of phenylenediamine, the highest degree of exhaustion and fixation values were shown by the derivatives of phelylene-1,3-diamine. The derivatives of ethylene-1,2-diamine showed the lowest degree of exhaustion and fixation values, which can be explained by spherical hindering or changes in reactivity. Application of those amines that ensure the linear chemical structure of the dye molecule causes an increase in the degree of exhaustion and fixation values. The results obtained show that the kind of diamine used as a bridging group and the kind of active compound affect the degree of exhaustion and consequently the degree of dye fixed on cellulose fibres. Acknowledgements The authors would like to express their gratitude to Dr. K Blus of the Department of Dyes, Technical University of Lodz, for synthesis of the reactive red dyes used in this work. References [1] J. Shore, Cellulosics Dyeing, ‘CHAPTER 4: Dyeing with reactive dyes’, Society of Dyers

and Colourists, Manchester 1995. [2] BASF Aktiengesellschaft, US Patent 6180765 B1, January 2001. [3] Dystar Textilfarben GmbH & Co., US Patent 6090163, July 2000. [4] BASF Aktiengesellschaft, US Patent 6359121 B1, March 2002. [5] Everlight USA Inc., US Patent 6068667, May 2000. [6] BASF Aktiengesellschaft, US Patent 6159250, December 2000. [7] E. Matyjas, E. Rybicki, Application of the bi-functional reactive dyes in periodical method

of dyeing. (Zastosowanie dwufunkcyjnych barwników reaktywnych w okresowych sposobach barwienia), IV Scientific Conference of the Faculty of Textiles (IV Konferencja Naukowa Wydziału Włókienniczego), Lodz 2001.

[8] A Łukoś , W. Ornaf, Reactive Dyes (Barwniki reaktywne), WPL Warsaw 1966. [9] W. Czajkowski, Reactive dyes for cellulose fibres. (Barwniki reaktywne do włókien

celulozowych), XVIII Training Seminar of Colourists (XVIII Seminarium Szkoleniowe Kolorystów), Szczyrk 2002.

[10] J. Kraska , B. Łandwijt, The Influence of chemical structure of the chromophoric grouping and diamines on the properties of the triazine reactive dyes. (Wpływ budowy chemicznej układu barwnego i dwuamin nawłaściwości dwureaktywnych barwników triazynowych), Textile Review (Przegląd Włókienniczy), (1979); 33: No.9, 507-510.

[11] J. Mielicki, On the conformity of dyes. (O zgodności barwników), XVIII Training Seminar of Colourists (XV Seminarium Szkoleniowe Kolorystów)., Szczyrk 2002.

[12] J. Mielicki, Outline of Colour Knowledge. (Zarys wiadomości o barwie), Foundation of Development of Polish Colourists (Fundacja Rozwoju Polskich Kolorystów) 1997.